FR3162155A1 - Method for controlling an exoskeleton to assist with walking activity - Google Patents

Abstract

One aspect of the invention relates to a method (100) for controlling a user's walking assistance exoskeleton, the method (100) comprising the steps of: measuring (110) the acceleration and angular velocity of the user's lumbar region using a six-axis inertial measurement unit, and the angle and rotational speed of hip actuators; determining (120), from the measurements, a phase of a walking activity cycle, a period of the walking activity, and the slope of the terrain on which the walking activity is performed; modulating (130) the intensity of the current supplied by the energy source as a function of the determined phase of the walking activity cycle, the determined period of the walking activity, and the determined slope of the terrain; and applying (140) the modulated current to the hip actuators. Figure to be published with the abbreviation: Figure 1

Description

Method for controlling an exoskeleton to assist with walking activity TECHNICAL FIELD OF THE INVENTION

The technical field of the invention is that of exoskeletons to assist in a walking activity.

The present invention relates in particular to a method of controlling an exoskeleton for assistance with walking activity.

TECHNOLOGICAL BACKGROUND OF THE INVENTION

An exoskeleton is a device attached to one or more limbs of a user's human body to restore their mobility or increase their physical capabilities.

Exoskeletons can assist a user in various tasks such as carrying heavy loads, walking, running, hiking, etc. Numerous applications are possible, including in the medical, industrial, sports, and military fields.

Depending on their intended applications, exoskeletons differ greatly. Thus, it is possible to divide exoskeletons into two main categories.

The first category concerns passive exoskeletons. Passive exoskeletons are not motorized. They incorporate materials and equipment that store and release energy during the user's movement. The term "user" refers to the person wearing the exoskeleton. This person can be a man or a woman of any age. Passive exoskeletons are often used for ergonomic purposes, to prevent repetitive strain injuries, or to assist in lifting tools or equipment. Thus, passive exoskeletons, such as the one disclosed in patent application WO2014109799A1, are primarily intended to assist able-bodied individuals in performing repetitive and/or potentially traumatic tasks. These passive exoskeletons do not require a control mechanism since the forces exerted by the exoskeleton on the user are generated in response to the user's movements.

A second category of exoskeletons concerns active exoskeletons. Active exoskeletons rely on systems, called actuators, such as motors, hydraulic or pneumatic systems, capable of increasing human force or reducing the body's energy consumption during movement. An active exoskeleton consists of one or more actuators, which could be an electric motor, for example. The actuator actively increases the power of the human body. Active exoskeletons designed to assist with walking actively participate in the flexion and/or extension of the user's hips. These exoskeletons may, for example, include an actuator located near each of the user's hips and generate torque around the flexion/extension axis of each hip.

Active exoskeletons for assisting walking require the implementation of a control method, for example, to control the intensity of the assistance provided by the hip actuators, i.e., the intensity of the torque generated by each hip actuator around the flexion/extension axis of each of these hips. US patent application US2021401324A1, for example, discloses a control method for an active exoskeleton for assisting walking based, in particular, on the recognition of a limb movement pattern using a machine learning method.

In this context, an improved control system is needed. Enhanced comfort and better adaptation to user and terrain characteristics when using the exoskeleton controlled by this system are particularly important.

The invention offers a solution to the problems mentioned above by adapting the assistance provided by the hip actuators according to three parameters: the duration of the walking activity, the phase of a walking activity cycle, and the slope of the terrain on which the walking activity is performed. These three parameters are predetermined using measurements taken at the exoskeleton's hip actuators, as well as measurements taken by a six-axis inertial measurement unit designed to be placed in the user's lumbar region.

• une source d’énergie électrique adaptée pour fournir un courant électrique,
• un premier et un second actionneurs de hanche adaptés pour assister une flexion et/ou une extension respectivement d’une première et une seconde hanches de l’utilisateur, une intensité d’assistance étant dépendante d’une intensité du courant électrique appliqué aux premier et second actionneurs,
• une centrale inertielle à six axes destinée à être placée au niveau d’une zone lombaire de l’utilisateur et adaptée pour mesurer une accélération et une vitesse angulaire de la zone lombaire de l’utilisateur,
• un processeur configuré pour mettre en œuvre le procédé,

One aspect of the invention relates to a method for controlling a user's walking assistance exoskeleton, the exoskeleton comprising:

• a suitable source of electrical energy to provide an electric current,
• a first and a second hip actuator adapted to assist flexion and/or extension respectively of a first and a second hip of the user, the intensity of assistance being dependent on the intensity of the electrical current applied to the first and second actuators,
• a six-axis inertial measurement unit designed to be placed in the user's lumbar region and adapted to measure acceleration and angular velocity of the user's lumbar region,
• a processor configured to implement the process,

• mesure :
  • d’une accélération et d’une vitesse angulaire de la zone lombaire de l’utilisateur par la centrale inertielle à six axes, et
  • d’un angle et d’une vitesse de rotation des premier et second actionneurs, la vitesse de rotation des premier et second actionneurs étant positive lors d’une flexion des hanches de l’utilisateur,
• détermination, à partir des mesures :
  • d’une phase d’un cycle de l’activité pédestre parmi au moins un ensemble de phases du cycle de l’activité pédestre, le au moins un cycle de l’activité pédestre étant défini pour la première hanche de l’utilisateur,
  • d’une période de l’activité pédestre parmi :
    • un début d’activité pédestre,
    • un milieu d’activité pédestre, et
    • une fin d’activité pédestre, et
  • d’une pente d’un terrain sur lequel l’activité pédestre est réalisée, la pente du terrain étant négative lors d’une descente et positive lors d’une montée,
• modulation de l’intensité du courant fourni par la source d’énergie en fonction de la phase déterminée du cycle de l’activité pédestre, de la période déterminée de l’activité pédestre et de la pente déterminée du terrain, et
• application du courant modulé aux premier et second actionneurs de hanche.

the process comprising the following steps:

• measure :
  • of the acceleration and angular velocity of the user's lumbar region by the six-axis inertial measurement unit, and
  • of an angle and a rotational speed of the first and second actuators, the rotational speed of the first and second actuators being positive during a flexion of the user's hips,
• determination, based on the measurements:
  • of a phase of a walking activity cycle from among at least one set of phases of the walking activity cycle, the at least one walking activity cycle being defined for the user's first hip,
  • from a period of pedestrian activity among:
    • a start of walking activity,
    • an environment conducive to pedestrian activity, and
    • the end of the walking activity, and
  • of a slope of terrain on which pedestrian activity is carried out, the slope of the terrain being negative during a descent and positive during an ascent,
• modulation of the current intensity supplied by the energy source according to the determined phase of the pedestrian activity cycle, the determined period of the pedestrian activity, and the determined slope of the terrain, and
• application of modulated current to the first and second hip actuators.

The control method according to the invention thus allows adaptation to the user's characteristics, particularly the characteristics of their walking activity. Furthermore, the control method allows for adjustment of the intensity of assistance provided at the start and end of the walking activity. The control method according to the invention also allows adaptation to the characteristics of the terrain on which the walking activity is performed, notably by taking into account the slope of the terrain. Thus, the user comfort of the exoskeleton is improved thanks to the control method according to the invention.

• la modulation de l’intensité du courant appliqué aux premier et second actionneurs de hanche est en outre effectué en fonction d’un niveau d’assistance déterminé par l’utilisateur,
• l’activité pédestre est une activité parmi :
  • une marche,
  • une marche nordique,
  • une randonnée,
  • une course,
  • une marche en raquettes,
  • un ski de randonnée, et
• le au moins un cycle de l’activité pédestre comprend un cycle générique avec l’ensemble des phases du cycle générique comprenant :
  • une phase de flexion débutant lorsque la flexion de la première hanche débute et se terminant lorsque l’extension de la première hanche débute,
  • une phase d’extension débutant lorsque l’extension de la première hanche débute et se terminant lorsque la flexion de la première hanche débute, et
• la détermination de la phase du cycle générique parmi l’ensemble des phases du cycle de l’activité pédestre comprend :
  • une détection d’une entrée dans la phase de flexion lorsque la vitesse angulaire du premier actionneur est nulle après avoir été négative, et
  • une détection d’une entrée dans la phase d’extension lorsque la vitesse angulaire du premier actionneur est nulle après avoir été positive,
• l’activité pédestre est une marche, et
• la pente du terrain est nulle ou positive, et
• le au moins un cycle de l’activité pédestre comprend un premier cycle de marche avec le premier cycle de marche comprenant un ensemble de phases comprenant :
  • une phase de début d’oscillation débutant lorsqu’un pied d’une première jambe comprenant la première hanche n’est plus en contact avec le terrain après avoir été en contact avec le terrain et se terminant lorsque la première jambe et une seconde jambe comprenant la seconde hanche se croisent dans un plan sagittal de l’utilisateur,
  • une phase de milieu d’oscillation débutant lorsque la première jambe et la seconde jambe se croisent dans le plan sagittal de l’utilisateur et se terminant lorsqu’un genou de la première jambe débute la descente vers le terrain,
  • une phase de fin d’oscillation débutant lorsque le genou de la première jambe débute la descente vers le terrain et se terminant à un contact entre le pied de la première jambe et le terrain,
  • une phase de début d’appui débutant au contact entre le pied de la première jambe et le terrain et se terminant lorsque la première jambe et la seconde jambe se croisent dans le plan sagittal de l’utilisateur,
  • une phase de milieu d’appui débutant lorsque la première jambe et la seconde jambe se croisent dans le plan sagittal de l’utilisateur et se terminant lorsque le pied de la première jambe n’est plus en contact avec le terrain après avoir été en contact avec le terrain,
• la détermination de la phase du premier cycle de marche parmi l’ensemble des phases du premier cycle de marche comprend :
  • une détection d’une entrée dans la phase de de début d’oscillation lorsque la vitesse angulaire du premier actionneur est nulle après avoir été négative,
  • une détection d’une entrée dans la phase de milieu d’oscillation lorsque :
    • l’angle du premier actionneur est plus grand que l’angle du second actionneur après avoir été plus petit, et
    • la vitesse de rotation du premier actionneur est supérieure à une vitesse de rotation seuil prédéterminée,
  • une détection d’une entrée dans la phase de fin d’oscillation lorsque la vitesse angulaire du premier actionneur est nulle après avoir été positive,
  • une détection d’une entrée dans la phase de début d’appui lorsque :
    • un impact avec le terrain est détecté, et
    • une durée depuis la détection de l’entrée en phase de fin d’oscillation est supérieure à une première durée prédéterminée, et
  • une détection d’une entrée dans la phase de milieu d’appui lorsque l’angle du second actionneur est plus grand que l’angle du premier actionneur après avoir été plus petit,
• l’activité pédestre est une marche, et
• la pente du terrain est négative, et
• le au moins un cycle de l’activité pédestre comprend un second cycle de marche avec le second cycle de marche comprenant un ensemble de phases comprenant :
  • une phase de début d’oscillation en descente débutant lorsque le pied de la première jambe n’est plus en contact avec le terrain après avoir été en contact avec le terrain et se terminant lorsque la première jambe et la seconde jambe se croisent dans le plan sagittal de l’utilisateur,
  • une phase d’oscillation en descente débutant lorsque la première jambe et la seconde jambe se croisent dans le plan sagittal de l’utilisateur et se terminant au contact entre le pied de la première jambe et le terrain,
  • une phase de début d’appui en descente débutant au contact entre le pied de la première jambe et le terrain et se terminant lorsque la première jambe et la seconde jambe se croisent dans le plan sagittal de l’utilisateur,
  • une phase d’appui en descente débutant lorsque la première jambe et la seconde jambe se croisent dans le plan sagittal de l’utilisateur et se terminant lorsque le pied de la première jambe n’est plus en contact avec le terrain après avoir été en contact avec le terrain, et
• la détermination de la phase du second cycle de marche parmi l’ensemble des phases du second cycle de marche comprend :
  • une détection d’une entrée dans la phase de début d’oscillation en descente lorsque :
    • un impact avec le terrain est détecté pour un membre inférieur comprenant la seconde hanche, et
    • une durée depuis la détection de l’entrée en phase de début d’appui est supérieure à une deuxième durée prédéterminée,
  • une détection d’une entrée dans la phase d’oscillation en descente lorsque :
    • la vitesse angulaire du second actionneur est nulle après avoir été positive, et
    • la vitesse angulaire du premier actionneur est positive,
  • une détection d’une entrée dans la phase de début d’appui en descente lorsque :
    • un impact avec le terrain est détecté pour un membre inférieur comprenant la première hanche, et
    • une durée depuis la détection de l’entrée en phase de début d’oscillation est supérieure à une troisième durée prédéterminée, et
  • une détection d’une entrée dans la phase d’appui en descente lorsque :
    • la vitesse angulaire du premier actionneur est nulle après avoir été positive, et
    • la vitesse angulaire du second actionneur est positive,
• la détermination de la pente du terrain est effectuée en tenant compte de l’angle du premier actionneur lors de l’entrée dans la phase de début d’appui,
• la modulation d’intensité comprend en outre une augmentation de l’intensité du courant appliquée aux premier et second actionneurs lorsque la pente déterminée augmente,
• la modulation de l’intensité du courant appliqué aux premier et second actionneurs en fonction de la phase déterminée du cycle de l’activité pédestre comprend la modulation de l’intensité du courant appliqué aux premier et second actionneurs en fonction de :
  • la détermination du cycle de l’activité pédestre en cours parmi :
    • le cycle générique,
    • le premier cycle de marche,
    • le second cycle de marche, et
  • la détermination d’une entrée dans la au moins une phase du cycle détecté,
• la détermination de la période de l’activité pédestre comprend :
  • une détection d’une entrée dans la période de début d’activité pédestre lorsqu’une donnée d’accélération mesurée par la centrale inertielle à six axes est supérieure à une première donnée d’accélération horizontale prédéterminée,
  • une détection d’une entrée dans la période de milieu d’activité pédestre lorsqu’une durée depuis la détection de l’entrée dans la période de début d’activité pédestre est supérieure à une quatrième durée prédéterminée, et
  • une détection d’une entrée dans la période de fin d’activité pédestre lorsque la donnée d’accélération horizontale calculée est inférieure à une seconde donnée d’accélération horizontale prédéterminée,
• la modulation de l’intensité du courant appliqué aux premier et second actionneurs en fonction de la période déterminée de l’activité pédestre comprend :
  • lorsque l’entrée dans la période de début d’activité pédestre est détectée, une augmentation d’un facteur de régulation de l’intensité modulée du courant appliqué aux premier et second actionneurs, l’augmentation du facteur de régulation étant effectuée en un premier temps prédéterminé et débutant à une valeur nulle et terminant à une valeur égale à 1,
  • lorsque l’entrée dans la période de milieu d’activité pédestre est détectée, le facteur de régulation est maintenu à la valeur égale à 1, et
  • lorsque l’entrée dans la période de fin d’activité pédestre est détectée, une diminution du facteur de régulation de l’intensité modulée du courant appliqué aux premier et second actionneurs, la diminution du facteur de régulation étant effectuée en un second temps prédéterminé et débutant à la valeur égale à 1 et terminant à la valeur nulle.

In addition to the characteristics mentioned in the preceding paragraph, the process according to one aspect of the invention may have one or more complementary characteristics from among the following, considered individually or in all technically possible combinations:

• Furthermore, the modulation of the current intensity applied to the first and second hip actuators is carried out according to a level of assistance determined by the user.
• Walking is one activity among:
  • a walk,
  • Nordic walking,
  • a hike,
  • a race,
  • a snowshoe hike,
  • a ski touring ski, and
• at least one cycle of pedestrian activity includes a generic cycle with all the phases of the generic cycle including:
  • a flexion phase beginning when flexion of the first hip begins and ending when extension of the first hip begins,
  • an extension phase beginning when the extension of the first hip begins and ending when the flexion of the first hip begins, and
• Determining the phase of the generic cycle from among all the phases of the pedestrian activity cycle includes:
  • detection of an entry into the bending phase when the angular velocity of the first actuator is zero after having been negative, and
  • detection of an entry into the extension phase when the angular velocity of the first actuator is zero after having been positive,
• Walking is an activity that involves walking, and
• the slope of the terrain is zero or positive, and
• at least one cycle of pedestrian activity includes an initial walking cycle, with the initial walking cycle comprising a set of phases including:
  • an initial oscillation phase beginning when one foot of the first leg, including the first hip, is no longer in contact with the ground after having been in contact with the ground, and ending when the first leg and a second leg, including the second hip, cross in a sagittal plane of the user,
  • a mid-oscillation phase beginning when the first and second legs cross in the user's sagittal plane and ending when one knee of the first leg begins its descent towards the ground,
  • a final phase of the swing beginning when the knee of the first leg starts its descent towards the ground and ending with contact between the foot of the first leg and the ground,
  • a phase of initial support beginning at the contact between the foot of the first leg and the ground and ending when the first leg and the second leg cross in the user's sagittal plane,
  • a mid-support phase beginning when the first and second legs cross in the user's sagittal plane and ending when the foot of the first leg is no longer in contact with the ground after having been in contact with the ground,
• Determining the phase of the first gait cycle from among all the phases of the first gait cycle includes:
  • detection of an entry into the oscillation start phase when the angular velocity of the first actuator is zero after having been negative,
  • detection of an entry into the mid-oscillation phase when:
    • The angle of the first actuator is larger than the angle of the second actuator, after having been smaller, and
    • the rotational speed of the first actuator is greater than a predetermined threshold rotational speed,
  • detection of an entry into the end-of-oscillation phase when the angular velocity of the first actuator is zero after having been positive,
  • detection of an entry into the initial support phase when:
    • An impact with the ground is detected, and
    • a duration since the detection of the entry into the end-of-oscillation phase is greater than a first predetermined duration, and
  • detection of an entry into the mid-support phase when the angle of the second actuator is greater than the angle of the first actuator after having been smaller,
• Walking is an activity that involves walking, and
• the slope of the terrain is negative, and
• at least one cycle of walking activity includes a second walking cycle, with the second walking cycle comprising a set of phases including:
  • a phase of initial downward oscillation beginning when the foot of the first leg is no longer in contact with the ground after having been in contact with the ground and ending when the first leg and the second leg cross in the user's sagittal plane,
  • a downward oscillation phase beginning when the first and second legs cross in the user's sagittal plane and ending at the contact between the foot of the first leg and the ground,
  • a phase of initial support during descent, beginning at the contact between the foot of the first leg and the ground and ending when the first and second legs cross in the user's sagittal plane,
  • a downhill support phase beginning when the first and second legs cross in the user's sagittal plane and ending when the foot of the first leg is no longer in contact with the ground after having been in contact with the ground, and
• Determining the phase of the second gait cycle from among all the phases of the second gait cycle includes:
  • detection of an entry into the onset phase of downward oscillation when:
    • An impact with the ground is detected for a lower limb including the second hip, and
    • a duration since the detection of entry into the initial support phase is greater than a second predetermined duration,
  • detection of an entry into the downward oscillation phase when:
    • the angular velocity of the second actuator is zero after having been positive, and
    • the angular velocity of the first actuator is positive,
  • detection of entry into the initial downhill support phase when:
    • An impact with the ground is detected for a lower limb including the first hip, and
    • a duration since the detection of the entry into the onset phase of oscillation is greater than a third predetermined duration, and
  • detection of entry into the downhill support phase when:
    • the angular velocity of the first actuator is zero after having been positive, and
    • The angular velocity of the second actuator is positive.
• The determination of the terrain slope is carried out taking into account the angle of the first actuator when entering the initial support phase.
• The intensity modulation further includes an increase in the current intensity applied to the first and second actuators as the determined slope increases.
• The modulation of the current intensity applied to the first and second actuators according to the determined phase of the pedestrian activity cycle includes the modulation of the current intensity applied to the first and second actuators according to:
  • determining the current pedestrian activity cycle from among:
    • the generic cycle,
    • the first walking cycle,
    • the second walking cycle, and
  • the determination of an entry into at least one phase of the detected cycle,
• Determining the period of pedestrian activity includes:
  • detection of entry into the period of onset of pedestrian activity when an acceleration data point measured by the six-axis inertial measurement unit is greater than a predetermined initial horizontal acceleration data point,
  • detection of entry into the mid-activity period when the duration since detection of entry into the early activity period exceeds a predetermined fourth duration, and
  • detection of entry into the end-of-pedestrian activity period when the calculated horizontal acceleration data is less than a second predetermined horizontal acceleration data point,
• The modulation of the current intensity applied to the first and second actuators according to the determined period of pedestrian activity includes:
  • When entry into the pedestrian activity start period is detected, an increase in a regulation factor of the modulated current intensity applied to the first and second actuators, the increase in the regulation factor being carried out initially at a predetermined time, starting at a value of zero and ending at a value equal to 1,
  • When entry into the period of mid-pedestrian activity is detected, the regulatory factor is maintained at a value of 1, and
  • when entry into the period of end of pedestrian activity is detected, a decrease in the regulation factor of the modulated intensity of the current applied to the first and second actuators, the decrease in the regulation factor being carried out in a second predetermined time and starting at the value equal to 1 and ending at the value zero.

• une source d’énergie électrique adaptée pour fournir un courant électrique,
• un premier et un second actionneurs de hanche adaptés pour assister une flexion et/ou une extension d’une première et une seconde hanches de l’utilisateur, une intensité d’assistance étant dépendante d’une intensité du courant électrique appliqué aux premier et second actionneurs,
• une centrale inertielle à six axes destinée à être placée au niveau d’une zone lombaire de l’utilisateur et adaptée pour mesurer une accélération et une vitesse angulaire de la zone lombaire de l’utilisateur, et
• un processeur configuré pour mettre en œuvre le procédé selon l’invention.

Another aspect of the invention relates to an exoskeleton for assisting a user with walking, comprising:

• a suitable source of electrical energy to provide an electric current,
• a first and a second hip actuator adapted to assist flexion and/or extension of the user's first and second hips, the intensity of assistance being dependent on the intensity of the electrical current applied to the first and second actuators,
• a six-axis inertial measurement unit designed to be placed in the user's lumbar region and adapted to measure acceleration and angular velocity in that region, and
• a processor configured to implement the process according to the invention.

The invention and its various applications will be better understood by reading the following description and examining the accompanying figures.

BRIEF DESCRIPTION OF THE FIGURES

• LaFIG. 1est un schéma synoptique illustrant les étapes d'un exemple du procédé de commande d’un exosquelette à une activité pédestre selon l'invention.
• Les figures 2, 5 et 12 sont des exemples de machine à états finis 200 compatibles avec le procédé selon l’invention.
• Les figures 3 et 4 sont des schémas synoptiques illustrant les phases d’exemples de cycles de marche compatibles avec le procédé selon l’invention.
• Les figures 6 à 11 sont des exemples de modulation de l’intensité du courant appliqué aux actionneurs compatibles avec le procédé selon l’invention.

The figures are presented for illustrative purposes only and are in no way limiting to the invention.

• There FIG. 1 is a synoptic diagram illustrating the steps of an example of the method for controlling an exoskeleton for pedestrian activity according to the invention.
• Figures 2, 5 and 12 are examples of finite state machines 200 compatible with the process according to the invention.
• Figures 3 and 4 are synoptic diagrams illustrating the phases of example walking cycles compatible with the process according to the invention.
• Figures 6 to 11 are examples of modulation of the intensity of the current applied to actuators compatible with the method according to the invention.

DETAILED DESCRIPTION

Unless otherwise specified, the same element appearing on different figures has a unique reference.

There FIG. 1 is a synoptic diagram illustrating the steps of an example of process 100 according to the invention.

Process 100 can be implemented by a processor, a microprocessor, or a microcontroller. A microcontroller is a compact integrated circuit designed to manage a specific operation within an integrated system. A typical microcontroller includes a processor, memory, and input/output (I/O) peripherals on a single chip. For example, Process 100 can be implemented by a processor within a walking assistance exoskeleton. The exoskeleton includes an electronic circuit (in one or more parts) equipped with at least one non-volatile memory and a processor for performing logic operations. It may also include one or more other memory types, such as random access memory (RAM) or other types like flash or microSD, and one or more additional processors. The exoskeleton also includes an electrical power source, such as a battery, adapted to supply an electrical current. This electrical current is supplied to two hip actuators. A first and a second hip actuator are adapted to assist flexion and/or extension of the user's first and second hips, respectively. In other words, the first hip actuator, for example, the left hip actuator, assists flexion and/or extension of the left hip, while the second hip actuator, for example, the right hip actuator, assists flexion and/or extension of the right hip. The intensity of the assistance provided by each hip actuator depends on the intensity of the electrical current applied to the first and second actuators. Thus, by modulating the intensity of the electrical current applied to the first and second actuators, the intensity of the assistance provided by the hip actuators is also modulated. The exoskeleton also includes a six-axis inertial measurement unit (IMU) designed to be placed in the user's lumbar region and adapted to measure the acceleration and angular velocity of the user's lumbar region. The term "lumbar zone" in this application refers to the area in the user's lower back. This zone encompasses the five lumbar vertebrae and surrounding muscle groups. The lumbar zone is also commonly referred to as the lumbar region. Optionally, the exoskeleton may include two six-axis inertial measurement units (IMUs) to be placed at each hip actuator. These IMUs are designed to measure the acceleration and orientation of each of the user's hips. The term "hip" in this application refers to the hip joint. Therefore, the hip in this application is a ball-and-socket joint, or ball-and-socket joint, structured around the round head of the femur and the acetabulum, which is part of the pelvis. The hip allows, in particular, flexion and extension movements. Hip flexion allows the femur to be raised towards the abdomen, or the torso to be brought towards the femur. Hip extension allows the femur to be moved away from the abdomen, or the torso to be moved away from the femur. In this application, the rotational speed of the hip actuators is positive during hip flexion and therefore negative during hip extension.

By "processor-driven," we mean that the steps, or virtually all of them, are executed by at least one processor or similar system. Thus, some steps are performed by the computer, possibly fully automatically or semi-automatically. In some examples, the triggering of at least some of the process steps can be achieved through user-computer interaction. The level of user-computer interaction required may depend on the intended level of automation and be balanced against the need to implement the user's requirements. In some examples, this level may be user-defined and/or predefined.

• une marche,
• une marche nordique, i.e. une pratique de marche avec des bâtons en pleine nature,
• une randonnée,
• une course,
• une marche en raquettes,
• un ski de randonnée,

Method 100 is a method for controlling an exoskeleton to assist a user in a walking activity. The walking activity performed by the user can be one of the following:

• a walk,
• Nordic walking, i.e., a form of walking with poles in nature,
• a hike,
• a race,
• a snowshoe hike,
• a ski touring ski,

The walking activity can be carried out outdoors, on terrain with one or more slopes. A slope is the incline of the terrain and can be defined as a difference in height in meters over a route, divided by the length of the route in meters. In this application, the slope is negative when descending the route and positive when ascending it.

The first step, 110, of process 100 involves measuring various data. Specifically, step 110 provides a measurement of the acceleration, along three axes and expressed in meters per second squared, and the angular velocity, also expressed in meters per second, of the user's lumbar region. These measurements are performed by the inertial measurement unit (IMU) designed to be placed in the user's lumbar region. It should be noted that from these measurements, it is possible to calculate the orientation, along three axes and expressed in a global coordinate system, of the user's lumbar region. When optional IMUs are used, measurements of the user's hip acceleration and orientation are also taken by these optional IMUs. It is also possible to measure the current applied to each actuator to ensure they are functioning correctly. Optionally, step 110 can also provide a measurement of the current applied to each of the actuators and/or a measurement of the angle and speed of rotation of each of the hip actuators.

All of these measurements can be carried out at a frequency between 100 and 1000 hertz, preferably between 800 and 850 hertz.

• l’activité pédestre en cours, et
• le terrain sur lequel l’activité pédestre est réalisée.

A second step 120 of process 100 includes the determination of several pieces of information concerning:

• the ongoing walking activity, and
• the terrain on which the walking activity takes place.

• Un état 210 de veille,
• Un état 220 de démarrage progressif,
• Un état 230 d’arrêt progressif,
• Un état 240 de marche,
• Un état 250 de transition entre la marche et la marche en descente,
• Un état 260 de marche en descente, et
• Un état 270 de transition entre la marche en descente et la marche.

This information is determined from the measurements taken in step 110. This determined information can, for example, be used to implement a finite state machine to control the exoskeleton. FIG. 2 is an example of a finite state machine 200 compatible with process 100. This finite state machine comprises 7 states:

• A state of alert 210,
• A state 220 of gradual start-up,
• A state 230 of gradual shutdown,
• A 240-day operating condition,
• A 250 transitional state between walking and downhill walking,
• A state of 260 walking downhill, and
• A 270 transitional state between downhill walking and walking.

The information determined in step 120 allows us to move from a first state to a second state. The possibility of moving from a first state to a second state is illustrated on the FIG. 2 indicated by an arrow. The standby state 210 can be the initial state, that is to say the state in which the exoskeleton is when it is put into operation.

During this step 120, the phase of a walking activity cycle is determined. It is worth noting that several sets of walking activity phases can be managed in parallel by process 100. For example, the different sets of phases in a walking activity cycle may depend on the type of walking activity or the characteristics of the terrain on which the walking activity is performed. It is also worth noting that this step can determine a phase of a cycle for several sets of cycles. Thus, this step can consist of simultaneously determining a first phase for one set of cycle phases and a second phase for a second set of cycle phases. The phases of a walking activity cycle are determined for a lower limb of the user. In one example, the phases of the first walking activity cycle are determined for the user's first lower limb from measurements 110, and the phases of the second walking activity cycle are determined for the user's second lower limb, also from measurements 110. In another example, the phases of the first walking activity cycle are determined for the user's first lower limb from measurements 110, and the phases of the second cycle are determined from the phases of the first walking activity cycle. Thus, method 100 makes it possible to determine the phases of a walking activity cycle for at least one lower limb or hip of the user, referred to as the first hip.

In an example consistent with the previous examples, a first walking activity cycle is a generic cycle. This walking activity cycle can be used for any type of walking activity. This generic cycle comprises two phases. The first phase of the generic cycle is a flexion phase. The flexion phase begins when the flexion of the first hip starts and ends when the flexion of the first hip is complete, or equivalently, when the extension of the first hip begins. The entry into the flexion phase can be detected using data measured by the first actuator. For example, the flexion phase can be considered to begin when the angular velocity of the first actuator is zero or positive after having been negative. The second phase of the generic cycle is an extension phase. The extension phase begins when the extension of the first hip starts and ends when the extension of the first hip is complete, or equivalently, when the flexion of the first hip begins. The detection of entry into the extension phase can be performed using data measured by the first actuator. For example, the extension phase can be considered to begin when the angular velocity of the first actuator is zero or negative after having been positive.

In an example consistent with the previous examples, two additional walking activity cycles can be used. These two walking activity cycles, called first and second walking cycles, are particularly suitable when the walking activity is a walk or a hike, but could potentially also be adapted to other types of walking activities.

A first walking cycle corresponds to walking on flat terrain or uphill, that is, when the slope is zero or positive. An example of the first walking cycle is illustrated in the FIG. 3 with a synoptic diagram comprising 5 phases labeled 310 to 350 on the FIG. 3 .

The first phase of the first gait cycle is the onset of oscillation. This phase is considered the first phase of the first gait cycle. It begins when the foot of the first leg (i.e., the leg with the first hip) is no longer in contact with the ground, specifically the toes of the first leg, after having been in contact with the ground. The onset of oscillation ends when the first leg and the second leg (i.e., the leg with the second hip) cross in the user's sagittal plane, after the first leg has been in front of the second leg in the user's sagittal plane. This event generally corresponds to the knee of the flying leg (i.e., the first leg) passing in front of the knee of the supporting leg (i.e., the second leg). Entry into the oscillation start phase is detected when the angular velocity of the first actuator is zero or positive after having been negative.

• l’angle du premier actionneur est plus grand que l’angle du second actionneur après avoir été plus petit, et
• la vitesse de rotation du premier actionneur est supérieure à une vitesse de rotation seuil prédéterminée, par exemple supérieure à une vitesse de rotation de 5 degrés par seconde.

A second phase 320 of the first gait cycle is a mid-swing phase. The mid-swing phase begins when the first and second legs cross in the user's sagittal plane. The mid-swing phase ends when one knee of the first leg begins its descent toward the ground. Furthermore, when the gait cycle is disturbed by the terrain or modified by the user, the mid-swing phase may sometimes end with the first leg's foot making contact with the ground. In this case, the end-swing phase is absent from the gait cycle. Entry into the mid-swing phase is detected when:

• The angle of the first actuator is larger than the angle of the second actuator, after having been smaller, and
• the rotation speed of the first actuator is greater than a predetermined threshold rotation speed, for example greater than a rotation speed of 5 degrees per second.

A third phase 330 of the first gait cycle is the end-swing phase. The end-swing phase begins when the knee of the first leg starts its descent toward the ground. The end-swing phase ends upon contact between the foot of the first leg and the ground. Entry into the end-swing phase is detected when the angular velocity of the first actuator is zero or negative after having been positive.

• un impact avec le terrain, par exemple entre le talon du membre inférieur comprenant la première hanche de l’utilisateur et le terrain, est détecté, et
• une durée depuis la détection de l’entrée en phase de fin d’oscillation est supérieure à une première durée prédéterminée, par exemple supérieure à une durée de 500 millisecondes.

A fourth phase (340) of the first gait cycle is the initiation of stance. The initiation of stance begins upon contact between the foot of the first leg and the ground. The initiation of stance ends when the first and second legs cross in the user's sagittal plane, after the first leg has been behind the second leg in the user's sagittal plane. Entry into the initiation of stance is detected when:

• An impact with the ground, for example between the heel of the lower limb including the user's first hip and the ground, is detected, and
• a duration since the detection of the entry into the end-of-oscillation phase is greater than a first predetermined duration, for example greater than a duration of 500 milliseconds.

It is worth noting that the impact with the ground can be detected during the final phase of the oscillation, but also potentially during the mid-oscillation phase. Furthermore, alternatively, the second condition for entering the initial support phase could be the time elapsed since the detection of the entry into the mid-oscillation phase, rather than the final phase.

A fifth phase, 350, of the first gait cycle is the mid-stance phase. The mid-stance phase begins when the first and second legs cross in the user's sagittal plane, after the first leg has been behind the second leg in the user's sagittal plane. The mid-stance phase ends when the foot of the first leg is no longer in contact with the ground after having been in contact with the ground. Entry into the mid-stance phase is detected when the angle of the second actuator is greater than the angle of the first actuator, after having been smaller.

These five phases follow one another to form the first walking cycle. In other words, when these five phases 310 to 350 are determined successively, a complete first walking cycle is determined.

The second walking cycle corresponds to walking downhill, that is, when the slope is negative. An example of the second walking cycle is illustrated in the FIG. 4 with a synoptic diagram comprising 4 phases labeled 410 to 440 on the FIG. 4 .

• un impact avec le terrain est détecté pour un membre inférieur comprenant la seconde hanche, par exemple entre le talon du membre inférieur comprenant la seconde hanche et le terrain, et
• une durée depuis la détection de l’entrée en phase de début d’appui est supérieure à une deuxième durée prédéterminée, par exemple supérieure à une durée de 100 millisecondes.

The first phase 410 of the second gait cycle is a downhill sway initiation phase. The downhill sway initiation phase is considered the first phase of the second gait cycle. The downhill sway initiation phase begins when the foot of the first leg is no longer in contact with the ground after having been in contact with the ground. The downhill sway initiation phase ends when the first and second legs cross in the user's sagittal plane, after the first leg has been in front of the second leg in the user's sagittal plane. Entry into the downhill sway initiation phase is detected when:

• An impact with the ground is detected for a lower limb including the second hip, for example between the heel of the lower limb including the second hip and the ground, and
• a duration since the detection of the entry into the start-of-support phase is greater than a second predetermined duration, for example greater than a duration of 100 milliseconds.

• la vitesse angulaire du second actionneur est nulle ou négative après avoir été positive, et
• la vitesse angulaire du premier actionneur est positive.

A second phase 420 of the second gait cycle is a downhill swing phase. The downhill swing phase begins when the first and second legs cross in the user's sagittal plane, after the first leg has been in front of the second leg in the user's sagittal plane. The downhill swing phase ends upon contact between the foot of the first leg and the ground. Entry into the downhill swing phase is detected when:

• the angular velocity of the second actuator is zero or negative after having been positive, and
• the angular velocity of the first actuator is positive.

• un impact avec le terrain est détecté pour un membre inférieur comprenant la première hanche, et
• une durée depuis la détection de l’entrée en phase de début d’oscillation est supérieure à une troisième durée prédéterminée, par exemple supérieure à une durée de 100 millisecondes.

A third phase 430 of the second gait cycle is a downhill stance initiation phase. The downhill stance initiation phase begins upon contact between the foot of the first leg and the ground. The downhill stance initiation phase ends when the first and second legs cross in the user's sagittal plane, after the first leg has been behind the second leg in the user's sagittal plane. Entry into the downhill stance initiation phase is detected when:

• An impact with the ground is detected for a lower limb including the first hip, and
• a duration since the detection of the entry into the onset phase of oscillation is greater than a third predetermined duration, for example greater than a duration of 100 milliseconds.

• la vitesse angulaire du premier actionneur est nulle ou négative après avoir été positive, et
• la vitesse angulaire du second actionneur est positive.

A fourth phase 440 of the second gait cycle is the initiation of stance. The initiation of stance begins when the first and second legs cross in the user's sagittal plane after the first leg has been behind the second leg in the user's sagittal plane. The initiation of stance ends when the foot of the first leg is no longer in contact with the ground after having been in contact with the ground. Entry into the initiation of stance is detected when:

• the angular velocity of the first actuator is zero or negative after having been positive, and
• the angular velocity of the second actuator is positive.

These four phases follow one another to form the second walking cycle. In other words, when these four phases 410 to 440 are determined successively, a complete second walking cycle is determined.

• un début d’activité pédestre,
• un milieu d’activité pédestre, et
• une fin d’activité pédestre.

Step 2 of Procedure 100 also includes determining a period of pedestrian activity. In this application, the term "period of pedestrian activity" refers to one of the following periods:

• a start of walking activity,
• an environment conducive to pedestrian activity, and
• the end of a walking activity.

In one example, consistent with the preceding examples, the determination of the walking activity period (120) includes the detection of entry into the onset of walking activity. Entry into the onset of walking activity can be detected when an acceleration value measured by the six-axis inertial measurement unit (IMU) exceeds a predetermined initial horizontal acceleration value, for example, a horizontal acceleration of 0.75 meters per second squared. Alternatively, or complementaryly, for the first gait cycle, entry into the onset of walking activity can be detected when entries into the mid-swing and stance phases have been detected.

In an example consistent with the previous examples, the determination of the walking activity period (120) includes the detection of entry into the mid-walking activity period. Entry into the mid-walking activity period can be detected when the time since the detection of entry into the start of the walking activity period is greater than a predetermined fourth duration, for example, greater than 200 milliseconds.

In one example, consistent with the previous examples, the determination of the walking activity period includes the detection of entry into the walking activity end period. Entry into the walking activity end period can be detected when the calculated horizontal acceleration data is less than a predetermined horizontal acceleration data point, for example, less than a horizontal acceleration of 0.75 meters per second squared.

The second step 120 of process 100 finally includes the determination of a slope of a terrain on which the pedestrian activity is carried out.

• la pente du terrain augmente lorsque l’angle du premier actionneur lors de l’entrée dans la phase de début d’appui augmente,
• la pente du terrain diminue lorsque l’angle du premier actionneur lors de l’entrée dans la phase de début d’appui diminue.

In an example consistent with the previous examples, the terrain slope is determined by considering the angle of the first actuator at the start of the support phase. By convention, the angle of the first actuator can be considered minimal, i.e., close to zero degrees, for full extension of the user's first hip, and maximal, i.e., close to 180 degrees, for full flexion of the user's first hip. Following this convention, it is possible, for example, to determine that:

• The slope of the terrain increases when the angle of the first actuator during the initial support phase increases.
• the slope of the terrain decreases when the angle of the first actuator during entry into the initial support phase decreases.

• un second cycle de marche complet est déterminé durant une cinquième durée prédéterminée, par exemple une durée de 1300 millisecondes, et
• l’angle du premier et du second actionneurs de hanche sont supérieurs à un angle prédéterminé, par exemple supérieur à 10 degrés en respectant la convention décrite précédemment.

In an example consistent with the previous examples, the slope of the terrain can also be determined by using the current walking cycle. FIG. 5 is a graph illustrating an example of a finite state machine 500 allowing the determination of whether the current running cycle is the first running cycle, marked 510 on the FIG. 5 , or the second walking cycle, noted 520 on the FIG. 5 The transition from state 510, corresponding to the first operating cycle, to state 520, corresponding to the second operating cycle, may be authorized when:

• a second complete walking cycle is determined during a fifth predetermined duration, for example a duration of 1300 milliseconds, and
• the angle of the first and second hip actuators are greater than a predetermined angle, for example greater than 10 degrees respecting the convention described previously.

• un second cycle de marche complet n’est pas déterminé durant la cinquième durée prédéterminée, par exemple une durée de 1300 millisecondes, et
• l’angle du premier actionneur de hanche est inférieur à un angle prédéterminé, par exemple inférieur à 10 degrés en respectant la convention décrite précédemment.

The transition from state 520, corresponding to the second operating cycle, to state 510, corresponding to the first operating cycle, may be authorized when:

• a second complete walking cycle is not determined during the fifth predetermined duration, for example a duration of 1300 milliseconds, and
• the angle of the first hip actuator is less than a predetermined angle, for example less than 10 degrees, respecting the convention described previously.

Returning to the FIG. 2 The transition from state 210 to state 220 may be permitted when entry into the start of walking activity is detected. The transition from state 220 to state 230, from state 260 to state 230, and from state 240 to state 230 may be permitted when entry into the end of walking activity is detected. The transition from state 220 to state 240 may be permitted when entry into the middle of walking activity is detected. The transition from state 240 to state 250 may be permitted when the second walking cycle is the current walking activity cycle detected. The transition from state 250 to state 260 can be allowed when the duration in state 250 exceeds a predetermined duration, for example, 1.3 seconds. The transition from state 260 to state 270 can be allowed when the first walking cycle is the detected current walking activity cycle. The transition from state 270 to state 240 can be allowed when the duration in state 250 exceeds a predetermined duration, for example, 1000 milliseconds, and preferably 2500 milliseconds.

A third step 130 of process 100 involves modulating the intensity of the current supplied by the energy source. In other words, step 130 involves modifying the intensity of the current applied to the hip actuators. This modulation is therefore performed according to the determined phase of the walking activity cycle, the determined period of the walking activity, and the determined slope of the terrain.

In an example consistent with the previous examples, the modulation 130 of the current intensity applied to the actuators also depends on a user-defined assistance level. For example, the user can choose a light, moderate, or high assistance level before or during the walking activity.

• le cycle générique,
• le premier cycle de marche, et
• le second cycle de marche.

In an example, consistent with the previous examples, the modulation 130 of the current intensity applied to the actuators according to the determined phase of the pedestrian activity cycle is performed based on the determination of the current pedestrian activity cycle among:

• the generic cycle,
• the first walking cycle, and
• the second walking cycle.

Furthermore, in this example, when the pedestrian activity cycle is determined, the current intensity applied to the actuators can also be modulated based on the detection of an input in at least one phase of the cycle. FIG. 6 Figure 600 illustrates an example of modulating the current intensity applied to the actuators for the first gait cycle. The vertical axis represents the normalized intensity of the assistance provided by the hip actuator. The horizontal axis represents time, normalized to the total time of the first gait cycle. The stance period is noted as 610 on the graph. FIG. 6 with the peak of the support period noted at 620. The oscillation period is noted at 630 on the FIG. 6 with the peak of the oscillation period noted at 640. The FIG. 7 Figure 700 illustrates an example of modulating the current intensity applied to the actuators for the second gait cycle. The vertical axis represents the normalized intensity of the assistance provided by the hip actuator. The horizontal axis represents time, normalized to the total time of the first gait cycle. The stance onset period is noted as 710 on the graph. FIG. 7 The support period is noted as 720 on the FIG. 7 with the peak of the support period noted at 730. The oscillation period is noted at 740 on the FIG. 7 with the peak of the oscillation period noted at 750. The modulation of the current intensity applied to the actuators based on the determination of an input in at least one phase of the detected cycle can, for example, include the time-dependent deformation of a predefined modulation of the current intensity based on the timing of the detected events. For example, compared to the FIG. 7 , when the 720 support period is twice as long relative to the gait cycle as the 720 support period in the graph of the FIG. 7 , the transition from a current intensity equal to -1 to a current intensity of zero does not take place over a period equal to 10% of the operating cycle but over a period equal to 20% of the operating cycle.

In one example, consistent with the previous examples, the modulation 130 of the current intensity applied to the actuators as a function of the determined slope further includes an increase in current intensity as the determined slope increases. FIG. 8 is a graph 800 illustrating five examples of linear increases in the current applied to the actuators, represented by the vertical axis and expressed in amperes, as a function of the hip angle at the beginning of the stance phase, represented by the horizontal axis and expressed in degrees. The choice between these five examples depends, for example, on the level of assistance determined by the user. FIG. 9 Figure 900 illustrates three examples of the non-linear increase in current intensity applied to the actuators, represented by the vertical axis and expressed in amperes, as a function of the hip angle at the beginning of the stance phase, represented by the horizontal axis and expressed in degrees. The choice between these three examples may also depend on the level of assistance determined by the user.

In an example consistent with the previous examples, the modulation 130 of the current intensity applied to the actuators based on the determined period of pedestrian activity includes an increase in a regulation factor of the modulated current intensity applied to the actuators when entry into the pedestrian activity start period is detected. The regulation factor is thus used as a factor for the modulated current intensity applied to the actuators. In other words, when the factor is zero, the current applied to the actuators is zero, and when the factor is equal to 1, the current applied to the actuators is the current modulated according to the other parameters. The increase in the regulation factor is, for example, carried out over a predetermined initial period, for example, 2 seconds. The increase begins at a value of zero and ends at a value of 1. FIG. 10 illustrates an example 1000 of linear increase in the intensity of the current applied to the actuators, represented by the vertical axis and expressed in amperes, as a function of time, represented by the horizontal axis and expressed in seconds, from the detection of entry into the period of onset of pedestrian activity.

In this example, the modulation 130 of the intensity of the current applied to the actuators as a function of the determined period of pedestrian activity also includes maintaining the regulation factor at a value equal to 1 when entry into the mid-period of pedestrian activity is detected and for the entire duration of the mid-period of pedestrian activity.

In this example, the modulation 130 of the current intensity applied to the actuators as a function of the determined period of pedestrian activity finally includes a decrease in the regulation factor of the modulated current intensity applied to the actuators when entry into the end period of pedestrian activity is detected, and for the entire duration of the middle period of pedestrian activity. The decrease in the regulation factor is carried out in a predetermined second step, for example, 0.5 seconds. The decrease in the regulation factor begins at a value of 1 and ends at a value of 0. FIG. 11 is an example 1100 illustrating a linear decrease in the intensity of the current applied to the actuators, represented by the vertical axis and expressed in amperes, as a function of time, represented by the horizontal axis and expressed in seconds, from the detection of entry into the period of end of pedestrian activity.

A fourth step 140 of process 100 involves applying the modulated current to the hip actuators. For example, a first electrical current is modulated for the first actuator using process 100, and a second electrical current is modulated, in parallel, according to the modulation of the first actuator. In another example, two processes 100 are implemented in parallel to control an exoskeleton. Thus, a first electrical current is modulated for the first actuator with the first implementation of process 100, and a second electrical current is modulated for the second actuator with the second implementation of process 100.

There FIG. 12 This is an example of a finite state machine compatible with process 100. State machine 1200 takes as input the measurements performed in step 110 and provides as output a current intensity 1220 to be applied to the hip actuators. These measurements are provided to a module, denoted 1230, comprising finite state machines 200, 300, and 400, and modifying the current intensity according to examples 600 and 700. This module allows the current intensity applied to the actuators to be modulated 130 according to the phase of the detected pedestrian activity cycle 120. Then, the measurements performed in step 110, the modulated current intensity, and the information determined by module 1230 are transmitted to module 1240, which allows the current intensity applied to the actuators to be modulated 130 according to the detected period 120 of the pedestrian activity. This module 1240 modifies the current intensity according to examples 800 or 900. Finally, the measurements taken in step 110, the modulated current intensity, and the information determined by modules 1230 and 1240 are transmitted to module 1250, which modulates the current intensity applied to the actuators according to the detected slope. This module 1240 includes the finite state machine and modifies the current intensity according to examples 1000 and 1100.

Claims (11)

Method (100) for controlling an exoskeleton to assist a user in a walking activity, the exoskeleton comprising:

• a suitable source of electrical energy to provide an electric current,
• a first and a second hip actuator adapted to assist flexion and/or extension respectively of a first and a second hip of the user, the intensity of assistance being dependent on the intensity of the electrical current applied to the first and second actuators,
• a six-axis inertial measurement unit designed to be placed in the user's lumbar region and adapted to measure acceleration and angular velocity of the user's lumbar region,
• a processor configured to implement the process (100),

the process (100) comprising the steps of:

• measurement (110):
  • of the acceleration and angular velocity of the user's lumbar region by the six-axis inertial measurement unit, and
  • of an angle and a rotational speed of the first and second actuators, the rotational speed of the first and second actuators being positive during a flexion of the user's hips,
• determination (120), from measurements (110):
  • of a phase of a walking activity cycle from among at least one set of phases of the walking activity cycle, the at least one walking activity cycle being defined for the user's first hip,
  • from a period of pedestrian activity among:
    • a start of walking activity,
    • an environment conducive to pedestrian activity, and
    • the end of the walking activity, and
  • of a slope of terrain on which pedestrian activity is carried out, the slope of the terrain being negative during a descent and positive during an ascent,
• modulation (130) of the intensity of the current supplied by the energy source as a function of the determined phase of the pedestrian activity cycle, the determined period of the pedestrian activity, and the determined slope of the terrain, and
• application (140) of the modulated current to the first and second hip actuators.

Method according to claim 1 wherein the modulation (130) of the intensity of the current applied to the first and second hip actuators is further carried out according to a level of assistance determined by the user. A method according to claim 1 or 2, wherein:

• Walking is one activity among:
  • a walk,
  • Nordic walking,
  • a hike,
  • a race,
  • a snowshoe hike,
  • a ski touring ski, and

• at least one cycle of pedestrian activity includes a generic cycle with all the phases of the generic cycle including:
  • a flexion phase beginning when flexion of the first hip begins and ending when extension of the first hip begins,
  • an extension phase beginning when the extension of the first hip begins and ending when the flexion of the first hip begins, and
• the determination (120) of the phase of the generic cycle among all the phases of the pedestrian activity cycle includes:
  • detection of an entry into the bending phase when the angular velocity of the first actuator is zero after having been negative, and
  • detection of an entry into the extension phase when the angular velocity of the first actuator is zero after having been positive.

A method according to any one of the preceding claims, wherein:

• Walking is an activity that involves walking, and
• the slope of the terrain is zero or positive, and
• at least one cycle of pedestrian activity includes an initial walking cycle, with the initial walking cycle comprising a set of phases including:
  • an initial oscillation phase beginning when one foot of the first leg, including the first hip, is no longer in contact with the ground after having been in contact with the ground, and ending when the first leg and a second leg, including the second hip, cross in a sagittal plane of the user,
  • a mid-oscillation phase beginning when the first and second legs cross in the user's sagittal plane and ending when one knee of the first leg begins its descent towards the ground,
  • a final phase of the swing beginning when the knee of the first leg starts its descent towards the ground and ending with contact between the foot of the first leg and the ground,
  • a phase of initial support beginning at the contact between the foot of the first leg and the ground and ending when the first leg and the second leg cross in the user's sagittal plane,
  • a mid-support phase beginning when the first and second legs cross in the user's sagittal plane and ending when the foot of the first leg is no longer in contact with the ground after having been in contact with the ground,
• the determination (120) of the phase of the first walking cycle among all the phases of the first walking cycle includes:
  • detection of an entry into the oscillation start phase when the angular velocity of the first actuator is zero after having been negative,
  • detection of an entry into the mid-oscillation phase when:
    • The angle of the first actuator is larger than the angle of the second actuator, after having been smaller, and
    • the rotational speed of the first actuator is greater than a predetermined threshold rotational speed,
  • detection of an entry into the end-of-oscillation phase when the angular velocity of the first actuator is zero after having been positive,
  • detection of an entry into the initial support phase when:
    • An impact with the ground is detected, and
    • a duration since the detection of the entry into the end-of-oscillation phase is greater than a first predetermined duration, and
  • detection of an entry into the mid-support phase when the angle of the second actuator is greater than the angle of the first actuator after having been smaller.

A method according to any one of claims 1 to 3, wherein:

• Walking is an activity that involves walking, and
• the slope of the terrain is negative, and
• at least one cycle of walking activity includes a second walking cycle, with the second walking cycle comprising a set of phases including:
  • a phase of initial downward oscillation beginning when the foot of the first leg is no longer in contact with the ground after having been in contact with the ground and ending when the first leg and the second leg cross in the user's sagittal plane,
  • a downward oscillation phase beginning when the first and second legs cross in the user's sagittal plane and ending at the contact between the foot of the first leg and the ground,
  • a phase of initial support during descent, beginning at the contact between the foot of the first leg and the ground and ending when the first and second legs cross in the user's sagittal plane,
  • a downhill support phase beginning when the first and second legs cross in the user's sagittal plane and ending when the foot of the first leg is no longer in contact with the ground after having been in contact with the ground, and
• the determination (120) of the phase of the second walking cycle among all the phases of the second walking cycle includes:
  • detection of an entry into the onset phase of downward oscillation when:
    • An impact with the ground is detected for a lower limb including the second hip, and
    • a duration since the detection of entry into the initial support phase is greater than a second predetermined duration,
  • detection of an entry into the downward oscillation phase when:
    • the angular velocity of the second actuator is zero after having been positive, and
    • the angular velocity of the first actuator is positive,
  • detection of entry into the initial downhill support phase when:
    • An impact with the ground is detected for a lower limb including the first hip, and
    • a duration since the detection of the entry into the onset phase of oscillation is greater than a third predetermined duration, and
  • detection of entry into the downhill support phase when:
    • the angular velocity of the first actuator is zero after having been positive, and
    • the angular velocity of the second actuator is positive.

Method according to claims 4 or 5 wherein the determination (120) of the slope of the ground is carried out taking into account the angle of the first actuator when entering the start-up phase of support. Method according to the preceding claim wherein the intensity modulation (130) further comprises an increase in the current intensity applied to the first and second actuators when the determined slope increases. A method according to any one of claims 4 to 7, wherein the modulation (130) of the current intensity applied to the first and second actuators as a function of the determined phase of the pedestrian activity cycle comprises modulating the current intensity applied to the first and second actuators as a function of:

• determining the current pedestrian activity cycle from among:
  • the generic cycle,
  • the first walking cycle,
  • the second walking cycle, and
• the determination of an entry into at least one phase of the detected cycle.

A method according to any one of the preceding claims, wherein the determination (120) of the period of pedestrian activity comprises:

• detection of entry into the period of onset of pedestrian activity when an acceleration data point measured by the six-axis inertial measurement unit is greater than a predetermined initial horizontal acceleration data point,
• detection of entry into the mid-activity period when the duration since detection of entry into the early activity period exceeds a predetermined fourth duration, and
• detection of an entry into the period of end of pedestrian activity when the calculated horizontal acceleration data is less than a second predetermined horizontal acceleration data.

A method according to the preceding claim, wherein the modulation (130) of the current intensity applied to the first and second actuators as a function of the determined period of pedestrian activity comprises:

• When entry into the pedestrian activity start period is detected, an increase in a regulation factor of the modulated current intensity applied to the first and second actuators, the increase in the regulation factor being carried out initially at a predetermined time, starting at a value of zero and ending at a value equal to 1,
• When entry into the period of mid-pedestrian activity is detected, the regulatory factor is maintained at a value of 1, and
• when entry into the period of end of pedestrian activity is detected, a decrease in the regulation factor of the modulated intensity of the current applied to the first and second actuators, the decrease in the regulation factor being carried out in a second predetermined time and starting at the value equal to 1 and ending at the value zero.

Exoskeleton to assist a user with walking activities, comprising:

• a suitable source of electrical energy to provide an electric current,
• a first and a second hip actuator adapted to assist flexion and/or extension of the user's first and second hips, the intensity of assistance being dependent on the intensity of the electrical current applied to the first and second actuators,
• a six-axis inertial measurement unit designed to be placed in the user's lumbar region and adapted to measure acceleration and angular velocity of the user's lumbar region, and
• a processor configured to implement the method according to any one of the preceding claims.