CN103040586A - External skeleton robot for exercising lower limbs and exercise control method thereof - Google Patents

Abstract

The invention relates to an exoskeleton robot used for lower limb exercise training and a motion control method thereof. The robot consists of four parts: a supporting balance frame, an exoskeleton mechanical leg, a treadmill and a control system. The motion control method provides two modes, namely passive walking movement and active walking movement mode: in the passive walking movement mode, the control robot drives the operator to complete a specific movement or move with the correct physiological gait trajectory; in the active walking movement mode, The robot suppresses the limited abnormal movement of the operator, directly corrects or generates the gait training trajectory expected by the operator through an adaptive controller, and indirectly realizes the purpose of the robot providing auxiliary force and resistance for walking motion. The invention can improve the movement ability of human limbs, assist people to carry out walking movement, and reduce the movement intensity of people under the condition of bearing weight or walking for a long time.

Description

Exoskeleton robot and its motion control method for lower limb exercise training

technical field

The invention relates to an exoskeleton robot used for lower limb exercise training and a motion control method thereof. An exoskeleton robot device mainly used for human lower limb motion information detection and lower limb motion assistance.

Background technique

With the advancement of science and technology, the improvement of living standards and the increasing pace of life, people are enjoying the convenience brought by various high-tech tools while ignoring the necessity of physical exercise. More and more young people His physical fitness continued to decline. On the other hand, our country, like many countries in the world, is entering an aging society, and the proportion of elderly people with limited mobility is also increasing. Therefore, it is very necessary to research and develop a booster device that improves the motor function of human limbs, helps people to perform lower limb exercise training, and enhances physical fitness.

The lower extremity exoskeleton robot is a device similar to the human exoskeleton. It can be worn by the operator to drive the human hip joints, knee joints and ankle joints to move in line with human walking. This walking assist mechanism not only has a simple Mechanical assist function, and can help users maintain walking balance.

At present, many researchers at home and abroad are carrying out research work on lower limb exoskeleton robots, but these exoskeleton mechanical legs have relatively few types of training movements, limited range of motion, and small range of motion. Most of them ignore the active movement intention of the operator's lower limbs. Lack of real-time feedback of motion information, the stability, safety and realism of operation need to be improved. the

Contents of the invention

The purpose of the present invention is to address the deficiencies in the prior art, provide an exoskeleton robot for lower limb exercise training and its motion control method, improve the movement ability of human body limbs, and introduce the operator's active movement intention, which enhances the operator's ability to exercise. Active participation, more complete and more realistic realization of the lower limbs assist walking movement.

In order to achieve the above-mentioned purpose, the research and design of the present invention are as follows: the lower extremity exoskeleton robot for improving the movement ability of human limbs includes four parts: a support balance frame, an exoskeleton mechanical leg, a treadmill and a control system. The lower end of the support balance frame is fixed to the treadmill, and the exoskeleton mechanical legs are fixed in the middle of the support balance frame. Sports Training.

The exoskeleton mechanical leg is composed of 2 exoskeleton mechanical legs, each mechanical leg has 3 rotational degrees of freedom, and the hip joint, knee joint, and ankle joint each have 1 degree of freedom, all of which are connected by rotation, which can simulate human walking The rotation of the three joints in the sagittal plane realizes the movement of three degrees of freedom. A linear driver for driving the mechanical leg and an angle sensor for measuring the joint rotation angle are installed at each joint, and a Vila pressure sensor is installed behind the linear driver to detect the driving force provided by the driver.

According to the different wishes of the operator, the control method of this lower extremity exoskeleton robot for improving the movement ability of human limbs implements two working modes: passive walking movement and active walking movement:

In the passive walking movement mode, the robot is controlled to suppress all abnormal movements of the operator, and drives the operator to complete a specific movement or move with a correct physiological gait trajectory. The operator does not need to use force by himself, and completely passively follows the robot to do walking movements;

In the active walking mode, the robot restrains the limited abnormal movement of the operator, and detects the joint driving force generated by the operator acting on the robot during the movement in real time, and then uses the inverse dynamics model to extract the human-computer interaction torque to judge the operator's lower limbs. The active movement intention of the operator, and use the impedance controller to convert the interactive torque into the correction amount of the gait trajectory, directly correct or generate the gait trajectory expected by the operator through the adaptive controller, and indirectly realize the walking assist force and resistance provided by the robot. The purpose is to enhance the operator's initiative.

The idea of the present invention is to use the lower limb exoskeleton robot to improve the movement ability of the lower limbs of the human body. According to the needs of the human body for assisted walking, it is divided into a passive walking movement mode in which the mechanical legs provide all the auxiliary force and an active walking movement mode in which the mechanical leg provides part of the auxiliary force. In passive mode, the mechanical legs provide all the strength and load-bearing capacity required for human walking, and drive the operator to walk on the treadmill with a standard physiological gait trajectory or complete specific movements. At this time, the position servo control method based on PD feedback is adopted. Effectively realize the tracking control of gait trajectory. In the active walking mode, taking into account the operator's initiative, the human-computer interaction torque is detected and extracted through the force sensor, and the impedance control model of the human-computer interaction torque and the deviation from the predetermined joint trajectory is established to realize the active training mode. impedance control. Impedance control is always based on a fixed reference trajectory, which can only produce deviations based on this trajectory, and it is difficult to adapt to the adjustment of different individual gait trajectories; because for some people, such as the elderly who partially or completely lose the ability to walk, it may be due to The incoordination of muscle strength caused by lower limb muscle spasm and muscle tension will make the change of human-computer interaction torque too large or too small, and the trajectory deviation calculated by the impedance control model will also be too large or too small. The dynamic trajectory will not completely conform to the physiological laws, which will inevitably affect the comfort of walking, and may even cause harm to the body. Therefore, a gait trajectory adaptive control algorithm is proposed, considering the operator's active participation intention from the overall effect.

The exoskeleton robot motion control method for lower limb exercise training is characterized in that the walking motion is divided into passive and active modes according to different needs of the human body, and in the active walking mode, impedance control or automatic mode can be selected according to the type of operator. Adaptive control method, the specific implementation process is as follows:

1. In the passive walking movement mode, the operator walks on the treadmill with a standard physiological gait trajectory or completes specific movements under the full drive of the exoskeleton mechanical legs, and detects the angles and angular velocities of each joint during walking in real time as The feedback signal adopts the position servo control method based on PD feedback to drive the mechanical legs to drive the operator to realize walking motion.

2. In the active walking movement mode, it is a typical double closed-loop control system model, the inner loop is a position control loop based on PD feedback, and the outer loop is a position-based impedance control force loop; during the walking movement, the joint driver is used The post-installed tension and pressure sensors collect in real time the driving force of each joint generated under the active force of the operator's lower limbs, and then combine the robot's inverse dynamics model to calculate and extract the human-computer interaction torque of each joint, thereby obtaining the operator's lower limb movement Intention: Use the impedance controller to convert the human-computer interaction torque of each joint into the position, velocity and acceleration correction of the corresponding gait trajectory to generate the gait trajectory expected by the operator; or use the first n Fourier series expansion Fit and calculate the correct physiological gait trajectory of each joint, determine its initial expression, and then parameterize the gait trajectory of each joint. Each joint uses 3 trajectory parameters to represent the scaling factor of the joint angle amplitude to realize the training stride Adjustment of the gait cycle; the adjustment factor of the gait cycle; the offset of the joint angle, which can change the flexion and extension of the hip joint, the flexion of the knee joint, and the plantar flexion and flexion of the ankle joint. Then the objective function is established by the best square approximation method of the Euclidean norm of each joint trajectory deviation, and the objective function is used to iteratively solve the joint angle trajectory parameters in each gait cycle range with the corresponding trajectory parameter initial value , from the overall effect to fit and calculate the parameterized gait trajectory, and then generate the trajectory expected by the operator, and input it into the position controller of the inner ring of the robot joint, and control the servo drive of each joint to achieve the desired trajectory output, thereby driving the robot Continuously adjust the walking trajectory according to the operator's active movement intention, indirectly realize the purpose of the robot to provide walking assistance force and resistance, and enhance the operator's initiative.

The motion control method of the exoskeleton robot used for the exercise training of the lower limbs of the present invention adopts two motion modes, passive and active walking modes, and obtains the active motion intention of the operator in the walking motion through specific motion functions, so as to drive the robot to completely drive Or assist the operator's lower limbs to realize walking motion. On the basis of better realization of passive movement, the control method introduces the operator's active movement intention, enhances the active participation of the operator, and realizes the lower limb assisted walking movement more completely and realistically.

According to above-mentioned invention research and design, the present invention adopts following technical scheme:

An exoskeleton robot for lower limb exercise training, including a support balance frame, an exoskeleton mechanical leg, a treadmill and a control system. It is characterized in that: the lower end of the supporting balance frame is fixedly connected with the treadmill; the exoskeleton mechanical leg is fixed in the middle of the supporting balance frame, and the sole of the foot is in contact with the running belt of the treadmill; the control system is connected with the treadmill and the exoskeleton mechanical Legs: The user wears the exoskeleton mechanical legs and performs exercise training on the treadmill through the control of the control system.

There are two exoskeleton mechanical legs, and each mechanical leg includes three joints of hip joint, knee joint and ankle joint, and each joint has 1 degree of freedom, all of which are rotationally connected; at each joint A linear driver and an angle sensor are installed, and a Wela pressure sensor is installed behind the linear driver.

The control system includes an industrial computer, a data acquisition card, a motion control card, a man-machine interface, a serial port, a signal processing circuit, a servo driver and a drive circuit; a limit switch, a force sensor and an angle encoding in the mechanical legs of the exoskeleton The device sends the signal to the signal processing circuit, and the processed data is transmitted through the data acquisition card and the industrial computer; the serial port is at the head of the treadmill, and the treadmill instruction and the speed of the treadmill are transmitted through the serial port and the industrial computer; the servo of the linear drive The control value and the motor encoder signal are connected to the motion control card through the servo driver and the drive circuit, and then the signal generated by the motion control card is connected to the industrial computer. The man-machine interface is displayed on the industrial computer.

An exoskeleton robot motion control method for lower limb exercise training, using the above-mentioned robot for exercise training, characterized in that the lower limb exercise training includes two working modes of passive walking movement and active walking movement according to the different wishes of the operator .

The above-mentioned control method, the control steps are as follows: When the industrial computer sends a command signal according to the control program realized by VC programming, and outputs the servo control value to the drive circuit through the motion control card, the servo drive can receive the command and control the linear drive to realize mechanical control. The legs drive the operator to walk; at the same time, the industrial computer sends instructions through the serial port to realize the synchronous and coordinated movement of the treadmill; the industrial computer collects the signals of the angle encoder, force sensor and limit switch in real time through the data acquisition card, and feeds back to the In the controller of the dynamic trajectory, the trajectory control in different modes is realized, and the current walking speed, cycle, training time, joint angle and human-computer interaction force information are displayed on the man-machine interface.

In the above control method, under the passive walking movement mode, the operator walks on the treadmill with a standard physiological gait trajectory or completes specific movements under the full drive of the exoskeleton mechanical legs, and detects the angles of each joint during walking in real time. The angular velocity is used as the feedback signal, and the position servo control method based on PD feedback is used to drive the mechanical legs to drive the operator to realize walking motion.

The above control method becomes a typical double-closed-loop control system model in the active walking movement mode. The inner loop is a position control loop based on PD feedback, and the outer loop is a position-based impedance control force loop; The tension and pressure sensor installed behind the driver collects in real time the driving force of each joint generated under the active force of the operator's lower limbs, and then combines the inverse dynamics model of the robot to calculate and extract the human-computer interaction torque of each joint, thereby obtaining the operator's lower limbs. Motion intention; use the impedance controller to convert the human-computer interaction torque of each joint into the position, velocity and acceleration correction of the corresponding gait trajectory, and generate the gait trajectory expected by the operator; then generate the trajectory expected by the operator and input it to In the position controller of the inner ring of the robot joints, the servo motors of each joint are controlled to achieve the desired trajectory output, thereby driving the robot to continuously adjust the walking trajectory according to the operator's active movement intention, and indirectly realizing the purpose of the robot providing walking assistance and resistance. Enhance operator initiative.

Compared with the prior art, the present invention has the following obvious outstanding substantive features and significant advantages:

The automated lower extremity exoskeleton robot is used to simulate the structure of human legs, assist people in walking, and reduce the exercise intensity of people in the case of weight-bearing or long-term walking. Two exercise modes are provided. In the passive mode, the gait cycle, stride, and exercise time of the assisted walking movement can be adjusted manually or automatically, which improves the automation of the assisted walking movement; the impedance parameter can be adjusted to adapt to the operator Different individual characteristics and exercise requirements; parameterization of gait trajectory, easy to realize online adjustment of gait trajectory in active training mode; control method introduces the operator's active movement intention, and can display and record assist walking in real time through VC programming Information such as speed, time, cycle, joint trajectory, driving force, and human-computer interaction torque can help the operator understand his walking state.

Description of drawings

Figure 1 is a schematic diagram of the lower extremity exoskeleton robot system;

Figure 2 is a structural diagram of the exoskeleton mechanical leg;

Fig. 3 is a schematic structural diagram of the control system;

Fig. 4 is a schematic diagram of the man-machine interface of the present invention;

Fig. 5 is a block diagram of the control principle of the present invention.

Detailed ways

Preferred embodiments of the present invention are described as follows in conjunction with the accompanying drawings:

Embodiment one:

Referring to Figures 1 and 2, a lower limb exoskeleton robot for lower limb exercise training consists of a supporting balance frame (1), exoskeleton mechanical legs (2), treadmill (3) and a control system. It is characterized in that: the lower end of the supporting balance frame (1) is fixedly connected with the treadmill, the exoskeleton mechanical leg (2) is fixed in the middle of the supporting balance frame (1), the soles of the feet are in contact with the running belt of the treadmill (3), and the user wears it Put on the exoskeleton mechanical leg (2), and perform exercise training on the treadmill (3) through the control of the control system.

Embodiment two:

This embodiment is basically the same as Embodiment 1, and the special features are as follows:

The exoskeleton mechanical leg (2) (see Figure 2) has three degrees of freedom of hip joint flexion/extension, knee joint flexion/extension, and ankle joint plantarflexion/dorsiflexion, which can simulate human walking in the sagittal plane. The rotation of the three joints realizes the movement of three degrees of freedom, and a ball screw linear drive (4) is installed at each joint to drive the movement of each joint of the orthosis. The walking lower extremity exoskeleton robot system provides the operator with single-joint motion and walking motion of each joint. The (6) angle sensors 6 installed at the hip, knee, and ankle joints are used to measure the joint angle during movement, and the (6) tension and pressure sensors (5) installed behind each linear actuator are used to detect the actuator (4) The driving force provided, both kinds of information are used to detect the walking motion state and applied in different motion modes.

The control system includes an industrial computer (14), a data acquisition card (12), a motion control card (13), a man-machine interface (15), a serial port (8), a signal processing circuit (9), and a servo driver (10) and drive circuit (11). Its structure is: the limit switch (7), the force sensor (5) and the angle encoder (6) in the exoskeleton mechanical leg (2) send the signal to the signal processing circuit (9), and the processed data passes through the data The acquisition card (12) and the industrial computer (14) are transmitted; the serial port (8) is at the head of the treadmill (3), and the treadmill instructions and the speed of the treadmill are transmitted through the serial port (8) and the industrial computer (14); the linear drive (4) The servo control value and the motor encoder signal are connected to the motion control card (13) through the servo driver (10) and the drive circuit (11), and then the signal generated by the motion control card (13) is connected to the industrial computer (14) connected. The man-machine interface (15) is displayed on the industrial computer (14).

Embodiment three:

Referring to Fig. 5, an exoskeleton robot motion control method for lower limb exercise training, using the above-mentioned robot for exercise training, is characterized in that: according to the different wishes of the operator, the lower limb exercise training includes passive walking and active walking Sport two working modes.

Embodiment four:

The present embodiment is basically the same as the third embodiment, and the special features are as follows:

The above-mentioned exoskeleton robot motion control method for lower limb exercise training, the control steps are as follows: when the industrial computer (14) sends out an instruction signal according to the control program realized by VC programming, and outputs the servo control amount to the In the driving circuit (11), the servo driver (10) can receive the command and control the linear driver (4) to realize the function of the mechanical leg driving the operator to walk; at the same time, the industrial computer (14) sends the command through the serial port (8) Realize the synchronous and coordinated movement of the treadmill; the industrial computer (14) collects the signals of the angle encoder (6), force sensor (5), limit switch (7) and so on through the data acquisition card (12) in real time, and feeds them back to the gait trajectory In the controller, trajectory control in different modes is realized, and current walking speed, cycle, training time, joint angle, human-computer interaction force and other information are displayed on the man-machine interface (15). See Figure 4 for the man-machine interface.

In the above-mentioned exoskeleton robot motion control method for lower limb exercise training, in the passive walking motion mode, the operator walks on a treadmill with a standard physiological gait trajectory or completes a specific motion under the full drive of the exoskeleton mechanical leg. The angle and angular velocity of each joint during walking are detected in real time as feedback signals, and the position servo control method based on PD feedback is used to drive the mechanical legs to drive the operator to realize walking motion.

The above-mentioned exoskeleton robot motion control method for lower limb exercise training is a typical double closed-loop control system model in the active walking motion mode, the inner loop is a position control loop based on PD feedback, and the outer loop is a position-based impedance Control the force ring; during the walking movement, the tension and pressure sensors installed behind the joint driver are used to collect the driving force of each joint under the active force of the operator's lower limbs in real time, and then combined with the robot's inverse dynamics model to calculate and extract the joints Human-computer interaction torque, so as to obtain the operator's lower limb movement intention; use the impedance controller to convert the human-computer interaction torque of each joint into the corresponding position, speed and acceleration correction of the gait trajectory, and generate the gait trajectory expected by the operator ; and then generate the trajectory expected by the operator, and input it to the position controller of the inner ring of the robot joints, control the servo motors of each joint to achieve the desired trajectory output, so as to drive the robot to continuously adjust the walking trajectory according to the operator's active movement intention, indirectly Realize the purpose of the robot providing walking assistance force and resistance force, and enhance the initiative of the operator.

Claims (7)

1. An exoskeleton robot for lower limb exercise training, comprising a support balance frame (1), an exoskeleton mechanical leg (2), a treadmill (3) and a control system, characterized in that: the support balance frame (1 ) is fixedly connected to the treadmill; the exoskeleton mechanical leg (2) is fixed in the middle of the supporting balance frame (1), and its sole is in contact with the running belt of the treadmill (3); the control system is connected to the treadmill (1) and the exoskeleton mechanical leg (2); the user wears the exoskeleton mechanical leg (2), and performs exercise training on the treadmill (3) through the control of the control system. 2. The exoskeleton robot for lower limb exercise training according to claim 1, characterized in that there are two exoskeleton mechanical legs (2), and each mechanical leg includes a hip joint, a knee joint and an ankle Joints Three joints, each joint has 1 degree of freedom, all of which are connected by rotation; a linear drive (4) and an angle sensor (6) are installed at each joint, and a one-dimensional drive (4) is installed behind the linear drive (4) Pull the pressure sensor (5). 3. The exoskeleton robot for lower limb exercise training according to claim 1, characterized in that: the control system includes an industrial computer (14), a data acquisition card (12), a motion control card (13), a human Machine interface (15), serial port (8), signal processing circuit (9), servo driver (10) and drive circuit (11); limit switch (7) and force sensor in the exoskeleton mechanical leg (2) (5) and the angle encoder (6) send the signal into the signal processing circuit (9), and the processed data is transmitted through the data acquisition card (12) and the industrial computer (14); the serial port (8) is connected to the treadmill (3 ), the treadmill command and the treadmill speed are transmitted through the serial port (8) and the industrial computer (14); the servo control amount of the linear driver (4) and the motor encoder signal are passed through the servo driver (10) and the drive circuit ( 11) Connect with the motion control card (13), and then communicate the signal generated by the motion control card (13) with the industrial computer (14); the man-machine interface (15) is displayed on the industrial computer (14). 4. an exoskeleton robot motion control method for lower limbs exercise training, adopting the exoskeleton robot for lower limbs exercise training according to claim 1 to carry out exercise training, it is characterized in that for the different wishes of the operator, the The lower limb exercise training includes two working modes: passive walking movement and active walking movement. 5. The exoskeleton robot motion control method for lower limb exercise training according to claim 4, characterized in that, the control step is as follows: when the industrial computer (14) sends out an instruction signal according to the control program realized by VC programming, and through The motion control card (13) outputs the servo control amount to the drive circuit (11), and the servo drive (10) can receive the instruction to control the linear drive (4) to realize the function of the mechanical legs driving the operator to walk; at the same time, the industrial control The machine (14) sends instructions through the serial port (8) to realize the synchronous and coordinated movement of the treadmill; the industrial computer (14) collects the angle encoder (6), the force sensor (5) and the limit switch ( 7) The signal is fed back to the controller of the gait trajectory to realize the trajectory control in different modes, and displays the current walking speed, cycle, training time, joint angle and human-computer interaction force information on the human-machine interface ( 15) on. 6. The exoskeleton robot motion control method for lower extremity exercise training according to claim 4, characterized in that under the passive walking motion mode, the operator, fully driven by the exoskeleton mechanical leg, walks on the treadmill with a standard physiological The gait trajectory is used to walk or complete a specific movement, and the angle and angular velocity of each joint during the walking process are detected in real time as feedback signals, and the position servo control method based on PD feedback is used to drive the mechanical legs to drive the operator to realize the walking movement. 7. The exoskeleton robot motion control method for lower extremity exercise training according to claim 4, characterized in that under the active walking motion mode, it becomes a typical double closed-loop control system model, and the inner loop is position control based on PD feedback The outer ring is a position-based impedance control force ring; in the process of walking, the tension and pressure sensors installed behind the joint driver are used to collect the driving force of each joint under the active force of the operator's lower limbs in real time, and then combined with the robot's The inverse dynamics model calculates and extracts the human-computer interaction torque of each joint, so as to obtain the operator's lower limb movement intention; uses the impedance controller to convert the human-computer interaction torque of each joint into the position, speed and acceleration correction of the corresponding gait trajectory , to generate the gait trajectory expected by the operator; then generate the trajectory expected by the operator, and input it into the position controller of the inner ring of the robot joint, control the servo motors of each joint to achieve the desired trajectory output, and thus drive the robot according to the operator's initiative The motion intention continuously adjusts the walking trajectory, indirectly realizes the purpose of the robot providing walking assistance force and resistance, and enhances the operator's initiative.

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