CN102755229B - Six-legged stair climbing wheelchair - Google Patents

Abstract

A hexapod stair climbing wheelchair system belongs to the field of service robots for helping the elderly and the disabled. It includes a wheelchair, 3 front legs of the chair, 3 legs of the back of the chair, and a power controller box; the power controller box is installed under the seat of the wheelchair, and has a built-in power supply and controller; the 3 front legs of the chair They are evenly arranged on the left, middle and right sides of the power controller box close to the front side of the wheelchair, and consist of hip joints, thighs, knee joints, lower legs, ankle joints and feet. Telescopic joints; the three chair back side legs are evenly arranged on the back side of the power controller box close to the wheelchair, and are composed of hip joints, thighs, knee joints, calves, ankle joints and feet; the invention ensures that the wheelchair The seat is always in a horizontal state during the entire stair climbing process, ensuring the comfort and safety of the occupant, and can also walk on rough and uneven roads conveniently.

Description

A hexapod stair climbing wheelchair

Technical field:

The invention relates to a wheelchair for helping the elderly and the disabled, in particular to a wheelchair capable of climbing stairs and crossing obstacles, and belongs to the field of service robots for helping the elderly and the disabled.

Background technique:

At present, known commonly used wheelchair devices adopt the form of wheeled movement, which can only walk on flat ground, but cannot cross obstacles such as steps and thresholds, let alone climb stairs, so the range of activities of wheelchair users is greatly restricted. At present, there are four special wheelchair devices with stair climbing ability: wheel set type, crawler type, track type and legged type (walking type). The wheel-set wheelchair (such as IBOT3000 in the United States) adopts a star-shaped wheel mechanism and can climb stairs and climb over curbs. The limitation of crawler wheelchairs is that the crawler walks on the stairs through the crawlers. The disadvantage is that the crawlers are easy to damage the stairs when climbing the stairs and anti-skid measures are required, so its application is limited; the track type needs to install a special track mechanism on the stairs. Due to the track mechanism It cannot be freely moved to different occasions with the wheelchair, and its application is also limited; legged wheelchairs such as Thehybrid all-terrain wheelchair researched by the University of Pennsylvania in the United States add two legs to the wheelchair, which can climb steps and overcome obstacles , but in the process of climbing steps and overcoming obstacles, the seat tilts seriously, causing great discomfort to the occupants.

Invention content:

In order to overcome the limitations of the existing stair climbing wheelchairs on the stair structure and the dependence on special facilities, this application provides a new stair climbing wheelchair scheme, which does not impose restrictions on the stair structure and does not depend on other special facilities. The facilities can not only ensure the safety of the occupants during the stair climbing process, but also ensure the comfort of the occupants during the stair climbing process.

The technical solution adopted by the present application to solve its technical problems is: 3 chair front side legs and 3 chair back side legs are provided with a total of 6 mechanical legs under the seat of an ordinary wheelchair, and each mechanical leg includes hip joints, thighs, Knee joints, lower legs, ankle joints and feet, the hip joints are connected upwards to the wheelchair and installed in the power controller box through thrust bearings, the hip joints are downwards connected to the thighs, the thighs and lower legs are connected through the knee joints, and the lower legs and feet are passed through The ankle joint is connected, and the hip joint and knee joint are driven by servo motors to realize the rotation of the thigh around the hip joint and the rotation of the lower leg around the knee joint. The intersection point is offset to the direction of the leg bend, so that the chair front leg and the chair back leg can be folded at the knee joint, and at the same time, the hip joint of the chair back leg bends a certain distance to the chair back side longitudinally, so that the chair front leg and the chair back leg The side legs of the chair back can be respectively folded and retracted to the bottom of the power controller box and the rear of the chair back.

The hexapod stair climbing wheelchair has two motion modes of wheel type and leg type: in the flat environment, the 3 front legs of the chair and the 3 legs of the back of the chair are respectively folded back to the bottom of the power controller box and the chair On the rear of the back, the system adopts the wheeled movement mode; in the environment that needs to climb stairs and cross obstacles, stretch out the folded 6 mechanical legs and adopt the walking movement mode.

The three front legs of the chair are evenly arranged on the front side of the power controller box close to the wheelchair, and the three chair back side legs are evenly arranged on the back side of the power controller box close to the wheelchair; There are two crawling gaits, slow crawling gait and fast triangular gait, as follows:

The slow crawling gait: only one leg is taken at a time, and the next leg is taken after this leg hits the ground, and at least 5 legs touch the ground at all times; the step sequence for going up stairs is: the back side of the middle chair Leg—right chair back leg—left chair back leg—center of gravity forward—right chair front leg—left chair front leg—middle chair front leg;

The fast triangular gait: the left and right legs on the back of the chair and the middle leg on the front of the chair form a group, the middle leg on the back of the chair and the left and right legs on the front of the chair form a group, and the three legs in the same group Step at the same time, this set of legs lands and then the next set of legs, the two sets of legs step alternately, always have at least 3 legs touching the ground;

Whether using a slow crawling gait or a fast triangular gait, the distance from the center of gravity of the hexapod stair climbing wheelchair to the support polygon boundary of the mechanical leg is at least approximately equal to the leftmost leg of the hexapod stair climbing wheelchair and 1/4 of the distance between the rightmost legs.

The thighs and calves of the three mechanical legs on the front side of the chair contain telescopic joints. The telescopic joints are composed of a movable part and a fixed part. The fixed part of the telescopic joint of the thigh is connected to the hip joint through stud nuts, and the movable part is connected to the knee joint through stud nuts. Connection, the fixed part of the telescopic joint of the calf is connected with the knee joint through stud nuts, and the movable part is connected with the ankle joint through stud nuts. During the climbing process of stairs, the front side of the wheelchair is in front, and the occupant is moving forward and down. Stairs; the back of the chair is at the front, and for the occupants, it is going up the stairs backwards. At this time, the position of the front legs of the wheelchair on the stairs is about 2-3 steps lower than that of the legs of the back of the chair. , the wheelchair adjusts the telescopic length of the telescopic joints of the front leg of the chair according to the stair step height difference between the front leg of the chair and the leg of the back of the chair, so that the leg of the front of the chair is longer than the leg of the back of the chair, and the leg of the front of the chair is longer than the leg of the chair back. The extra length of the side legs of the chair back is equal to the height difference between the front legs of the chair and the legs of the back of the chair on the stairs, so that the seat of the wheelchair is always kept in a horizontal state during the stair climbing process, ensuring the comfort and comfort of the passengers. safety.

The 6 mechanical legs are evenly arranged on the front side of the chair and the back side of the chair on the left, middle and right sides, so whether it is a slow crawling gait (6 legs move in sequence, only one leg at a time), or a fast triangular step state (3 legs separated from each other form a group, and the 3 legs in the same group move at the same time), it can ensure that the center of gravity of the wheelchair is always within the support polygon of the mechanical legs, and the system has a good stability margin and will not overturn , so as to ensure the safety of the occupants. The ankle joint of the mechanical leg is not driven by a motor, and the joint bearing is installed. The foot can rotate a certain angle around the axis perpendicular to the forward direction and the axis parallel to the forward direction at the ankle joint, so that the wheelchair can adapt to unevenness. It is convenient to use the walking motion mode to walk on the potholes.

The telescopic joints of the thighs and calves of the three mechanical legs on the front side of the chair are realized by the ball screw nut mechanism. The ball screw adopts the "fixed-free" installation method, and the fixed end is connected by a two-way passive self-locking bearing and a servo motor drive assembly. , the nut mechanism is connected with the movable part of the telescopic leg. The shape of the movable part of the telescopic leg is a square prism. There are 4 rows of rolling guide blocks on the four sides of the prism. The fixed part of the telescopic leg is a hollow regular square prism. There is a row of guide grooves on each of the 4 planes. The movable part is set inside the fixed part and slides in the guide groove of the fixed part through the rolling guide block, so that the telescopic part of the mechanical leg can be freely expanded and contracted under the drive of the servo motor. Adjusting the length of the mechanical legs can also prevent the ball screw from rotating reversely under stress, thereby ensuring the safety of the system while realizing the telescopic function of the mechanical legs.

The hip joints of the front legs of the chair and the legs of the back of the chair are upwardly installed in the power controller box through thrust bearings, and driven by a servo motor, so that the legs of the front of the chair and the legs of the back of the chair can rotate around the vertical axis, thereby Realize the steering operation of the hexapod stair climbing wheelchair system.

The ankle joints of the front and back legs of the chair are equipped with joint bearings, and an under-actuated scheme without motor drive is adopted. Since the axes of the joint bearings can deflect, the feet of the six mechanical legs can rotate around the ankle joints. The left and right direction axis can be pitched up and down by 20°, and it can also be tilted by 15° around the front and rear direction axis, so that the front side legs and the back side legs of the chair can adapt to uneven ground, and it is convenient to use walking on potholes. Sport mode for walking.

The beneficial effect of this application is that the system adopts the wheeled motion mode on the flat road surface, retains the original motion function of the wheelchair, and adopts the walking motion mode in the environment of steps and stairs, which is not limited by the structure of the stairs and does not depend on special special facilities. During the stair climbing process, the seat is always maintained in a horizontal state, which can ensure the safety and comfort of the occupants, and the system also has good adaptability on uneven ground.

Description of drawings:

The application will be further described below in conjunction with the accompanying drawings and embodiments.

Fig. 1 is that a hexapod stair climbing wheelchair adopts a walking motion state to start climbing stairs.

Fig. 2 is that the hexapod stair climbing wheelchair adopts the wheeled motion state to walk on level ground.

Fig. 3 is a schematic diagram of the structure and folding of the mechanical leg, and the thigh and shank of the side leg of the chair back have no telescopic joints.

Fig. 4 is the specific structure of the telescoping joint of the front leg of the chair and the shank.

Fig. 5 is the direction of movement of the hexapod stairs climbing wheelchair front leg and chair back side leg rotation and telescopic joint.

Fig. 6 shows that the hexapod stair climbing wheelchair keeps the seat in a horizontal state on the stairs through telescopic legs.

Fig. 7 is the motion direction of the hexapod stair climbing wheelchair going up and down between two floors of stairs.

Figure 8 shows the position of the center of gravity and the supporting polygon when the hexapod climbs a wheelchair and walks fast (triangular gait).

Figure 9 shows the position of the center of gravity and the support polygon when the hexapod stair climbing wheelchair walks slowly (crawling gait).

In the figure 1. Chair back, 2. Chair back side legs, 3. Power controller box, 4. Rear wheel, 5. Chair front side leg, 6. Front wheel, 7. Footboard, 8. Seat, 9. Armrest , 10. The longitudinal axis of the hip joint, 11. The hip joint, 12. The ankle joint, 13. The foot, 14. The calf telescopic joint of the chair front leg, 15. The knee joint, 16. The thigh telescopic joint of the chair front leg, 19. Gear box, 20. gear set, 21. servo motor, 22. two-way passive self-locking bearing, 23. ball screw fixed shaft end, 24. ball screw, 25. ball screw nut, 26. telescopic leg fixed part side Plate, 27. rolling guide block column, 28. movable part of telescopic leg, 29. calf of chair back side leg, 30. chair back side leg thigh, 31. longitudinal axis of hip joint of chair back side leg, 32. thrust bearing.

Detailed ways:

In Fig. 1, 6 mechanical legs are evenly distributed under the seat of the wheelchair on the front side of the chair and the back side of the chair on the left, middle and right sides. As shown in Figure 3, the structure of the mechanical leg is similar to that of a human leg. It is divided into a longitudinal axis of the hip joint 10, a hip joint 11, a thigh 30, a knee joint 15, a calf 29, an ankle joint 12, a foot 13, and a hip joint 11. The bottom is connected with the thigh 30 , the thigh 30 is connected with the lower leg 29 through the knee joint 15 , and the lower leg 29 is connected with the foot 13 through the ankle joint 12 . The vertical axis 10 of the hip joint is installed upwards in the power controller box 3 through the thrust bearing 32, and is driven by a servo motor so that the front leg 5 of the chair and the leg 2 of the back of the chair can rotate around the vertical axis, thereby realizing the hexapod stair climber. Steering operation of climbing wheelchair system. The direction of the mechanical legs is opposite to that of the wheelchair, so when going up the stairs, the back of the wheelchair is in front, and the occupant is going up the stairs backwards; when going down the stairs, the front side of the wheelchair is in front, and the occupant is walking backwards. Yan is going down the stairs. A power controller box 3 is arranged under the seat 8, and the hip joint longitudinal axis 10 of the mechanical leg is fixed in the power controller box 3 through a pair of thrust ball bearings and driven by a servo motor, so that the whole mechanical leg circles The shown z-axis turns to change the forward direction of the wheelchair to realize turning motion.

In Fig. 3, the large and small legs of the chair front side legs 5 also have telescopic joints. The structure of the telescopic joints is shown in Fig. 4. The telescopic joints are composed of movable parts and fixed parts. Joint 11 is connected, and movable part is connected with knee joint 15 by stud nut, and the fixed part of chair front side leg calf telescopic joint 14 is connected with knee joint 15 by stud nut, and movable part is connected with ankle joint 12 by stud nut. The telescopic joint is realized by a ball screw nut mechanism. The ball screw 24 adopts a "fixed-free" installation method. The fixed shaft end 23 of the ball screw is driven by a bidirectional passive self-locking bearing 22, a servo motor 21, and a reduction gear set 20. connect. The fixed shaft end 23 of the ball screw is installed together with the gear box 19 and the fixed part of the telescopic leg through the bearing. The telescopic leg fixing part is fixed into a hollow regular quadrangular prism by 4 identical side plates 26 by screws, and 1 row of guide grooves is respectively arranged on 4 planes of its inner surface. The ball screw nut 25 is connected with the movable part 28 of the telescopic leg. The profile of the movable part 28 of the telescopic leg is a regular square prism. Four rows of rolling guide blocks 27 are arranged on the four sides of the prism. The movable part 28 of the telescopic leg is enclosed within the fixed part and The rolling guide block 27 slides in the guide groove of the side plate 26 of the fixed part. The telescoping joint of the mechanical leg is upwardly connected with the telescoping joint of the upper mechanical part thigh and the hip joint 11 through the gear box 19, and the telescoping joint 14 of the lower leg of the chair front side is connected with the knee joint 15 and fixed by a screw nut. The movable part 28 of the mechanical leg telescopic joint is connected downward with the movable part of the lower mechanical part thigh telescopic joint and the knee joint 15, and the movable part of the lower leg telescopic joint 14 of the chair front side is connected with the ankle joint 12 and fixed by a screw nut. In this way, the telescopic joint of the mechanical leg can be freely stretched and contracted under the drive of the servo motor 21 to adjust the length of the mechanical leg, and can prevent the ball screw 24 from rotating in reverse under a stressed state, so that the telescopic function of the mechanical leg can be realized. Ensure system security.

Whether it is the chair front side leg 5 or the chair back side leg 2, the ankle joint 12 is equipped with joint bearings, and an underactuated scheme without motor drive is adopted. Since the axis of the joint bearing can deflect within a certain angle range, Therefore, the foot 13 can be pitched up and down by 20° around the left and right direction axis at the ankle joint 12, and can also be tilted by 15° left and right around the front and rear direction axis. Therefore, the wheelchair can adapt to uneven ground, and can also be used on potholes. Conveniently walk with walking motion mode.

As shown in Figure 3, the centers of the knee joints 15 of the chair front side legs 5 and the chair back side legs 2 are all biased to the leg bending direction at the intersection of the thigh and the shank for a certain distance, so that the chair front side legs 5 and the chair back side The leg 2 can be folded at the knee joint 15, and at the same time, the longitudinal axis 31 of the hip joint of the leg on the back of the chair is bent for a certain distance to the back of the chair, so that the leg 5 on the front side of the chair and the leg 2 on the back side of the chair can be folded back into the power controller box 3 and behind the back of the chair, the hexapod stair climbing wheelchair system thus has two modes of motion, wheeled and legged. In the embodiment shown in Figure 2, when the wheelchair is in a flat environment, as shown in Figure 5, the telescopic joints of the large and small legs of the front leg 5 of the chair are retracted, the thigh rotates counterclockwise around the hip joint 11, and the calf rotates around the knee joint 15 Turn clockwise, fold the front side leg 5 of the chair under the power controller box 3; The legs 2 are folded behind the back 1 of the chair. The wheelchair lands on the ground through the rear wheels 4 and the front wheels 6, and adopts a wheeled motion state.

In the embodiment shown in Figure 7, considering the parallelogram structural characteristics of the space between the two stairs, and the structure of the wheelchair and the sitting posture of the person, the front is low and the rear is high, so the wheelchair adopts forward movement during the stair climbing process. The way of going down the stairs and going backwards up the stairs, that is, the occupant of the wheelchair goes down the stairs facing the forward direction, and goes up the stairs with his back facing the forward direction. As shown in Figure 1, when the wheelchair moves to the vicinity of the stairs, contrary to the movement of the rotating joints of the legs shown in Figure 5, the thigh of the front leg 5 of the chair rotates clockwise around the hip joint 11, and the calf rotates counterclockwise around the knee joint 15 Rotate, stretch out the chair front side leg 5 that is folded under the power controller box 3; The chair back side legs 2 behind the back 1 are stretched out. After the 6 mechanical legs land on the ground, the rear wheel 4 and the front wheel 6 leave the ground, and the wheelchair adopts the 6-legged walking motion state, as shown in Figure 1, and starts the stair climbing process. As shown in Figure 1, when the wheelchair is ready to climb the stairs, the front side legs 5 and the back side legs 2 all stand on the same plane, so the telescopic joints of the legs 5 on the front side of the chair are in a retracted state. Along with the stair climbing process, the footholds of the chair front side legs 5 and the chair back side legs 2 are on planes of different heights, and at this moment the large and small leg telescopic joints of the chair front side legs 5 stretch out. As shown in Figure 6, when the wheelchair was in the middle of the stairs, that is, when the footholds of the chair front side legs 5 and the chair back side legs 2 of the wheelchair were all on the stair steps, the stair height difference between the footholds remained Therefore, the telescopic length of the large and small leg telescopic joints of the front side legs 5 of the chair remains unchanged substantially, and only corresponding fine-tuning is made as the tilt angle of the mechanical legs changes forward and backward when the wheelchair moves the center of gravity forward and backward. When the wheelchair climbs to the end of the stairs, that is, when the wheelchair gradually leaves the stairs and reaches the level ground, the height difference between the footholds of the front leg 5 and the back leg 2 gradually becomes smaller, and the height of the front leg 5 gradually decreases. The telescopic joints of the calf are gradually retracted. In this way, by adjusting the extension and retraction length of the telescopic joint, it can be ensured that the wheelchair seat 8 is always in a horizontal state, thereby ensuring the comfort and safety of the occupant. When the wheelchair reaches the level ground, the mechanical legs are retracted in the embodiment shown in Figure 2, and the wheeled motion state is returned.

In the embodiment shown in FIG. 8, the wheelchair walks in a triangular gait. This is a fast walking style. The left and right legs on the back side of the chair and the middle leg on the front side of the chair form a group, and the middle leg on the back side of the chair and the left and right side legs on the front side of the chair form a group, marked as A and B respectively , the 3 legs of the same group step forward at the same time, this group of legs lands and then the next group of legs, always at least 3 legs touch the ground. The operation process is as follows: the legs of group A stand, and the legs of group B step; the legs of group A and B touch the ground at the same time, and the center of gravity of the wheelchair moves forward; the legs of group B stand, and the legs of group A step; Group legs stand, group B legs step...  This cycle goes on and on, so that the wheelchair walks at a faster speed.

In the embodiment shown in Figure 9, the wheelchair walks in a crawling gait. This is a slow walking method. The 6 mechanical legs numbered 1~6 move in sequence. Only one leg is taken at a time, and the next leg is taken after one leg lands. At least 5 legs always touch the ground. The operation process is as follows: the No. 2 leg in the middle of the back of the chair is first stepped out, followed by the No. 1 and No. 3 legs on the back side of the chair, and then the six legs touch the ground at the same time, the center of gravity of the wheelchair moves forward, and then step out in front of the chair in turn. Legs 4 and 6 on the side, and finally step out to leg 5 in the middle of the front of the chair. At this point, a step cycle is completed, and then the next cycle of walking motion is started.

In the embodiment shown in Fig. 8 and Fig. 9, whether it is the crawling gait of slow walking or the triangular gait of fast walking, it can be ensured that the center of gravity of the wheelchair (indicated by G and ★) is always within the support polygon of the mechanical leg The system has a good stability margin and will not overturn, thereby ensuring the safety of the occupants.

Claims (6)

1. A hexapod stair climbing wheelchair is characterized in that, it is provided with 3 chair front side legs and 3 chair back side legs total 6 mechanical legs under the seat of the wheelchair, and each mechanical leg includes hip joint, Thighs, knee joints, calves, ankles and feet, the hip joints are connected upwards to the wheelchair and installed in the power controller box through thrust bearings, the hip joints are downwards connected to the thighs, thighs and calves are connected through knee joints, calves and feet The hip joint and knee joint are driven by servo motors to realize the rotation of the thigh around the hip joint and the rotation of the lower leg around the knee joint. The knee joint centers of the front leg and the back leg are between the thigh and The intersection point of the lower legs is offset towards the leg bend, so that the front leg and the back leg can be folded at the knee joint, and at the same time, the hip joint of the back leg bends for a certain distance to the back side of the chair, so that the front side of the chair The legs and the side legs of the chair back can be folded and retracted to the bottom of the power controller box and the back of the chair back; The hexapod stair climbing wheelchair has two motion modes of wheel type and leg type: in the flat environment, the 3 front legs of the chair and the 3 legs of the back of the chair are respectively folded back to the bottom of the power controller box and the chair At the rear of the back, the hexapod stair climbing wheelchair adopts the wheeled motion mode; in the environment that needs to climb stairs and cross obstacles, the folded 6 mechanical legs are stretched out, and the walking motion mode is adopted. 2. The hexapod stair climbing wheelchair according to claim 1, characterized in that: the three front legs of the chair are evenly arranged on the front side of the power controller box close to the wheelchair, and the three chair back sides The legs are evenly arranged on the back side of the power controller box near the wheelchair; there are two walking gaits: slow crawling gait and fast triangular gait, as follows: The slow crawling gait: only one leg is taken at a time, and the next leg is taken after this leg hits the ground, and at least 5 legs touch the ground at all times; the step sequence for going up stairs is: the back side of the middle chair Leg—right chair back leg—left chair back leg—center of gravity forward—right chair front leg—left chair front leg—middle chair front leg; The fast triangular gait: the left and right legs on the back of the chair and the middle leg on the front of the chair form a group, the middle leg on the back of the chair and the left and right legs on the front of the chair form a group, and the three legs in the same group Step at the same time, this set of legs lands and then the next set of legs, the two sets of legs step alternately, always have at least 3 legs touching the ground; Regardless of whether a slow crawling gait or a fast triangular gait is used, the distance from the center of gravity of the hexapod stair climbing wheelchair to the support polygon boundary of the mechanical leg is at least equal to the leftmost leg and the most extreme leg of the hexapod stair climbing wheelchair. 1/4 of the distance between the right legs. 3. The hexapod stair climbing wheelchair according to claim 1, characterized in that: the thighs and shanks of the three mechanical legs on the front side of the chair contain telescopic joints, the telescopic joints are composed of movable parts and fixed parts, and the telescopic joints of the thighs The fixed part is connected with the hip joint through the stud nut, the movable part is connected with the knee joint through the stud nut, the telescopic joint of the lower leg is connected with the knee joint through the stud nut, and the movable part is connected with the ankle joint through the stud nut. During the climbing process, the front side of the wheelchair is in front, and the occupant is going forward and down the stairs; the back of the chair is in front, and the occupant is going backward up the stairs, at this time, the front legs of the wheelchair are on the stairs. The position is 2-3 steps lower than the position of the side legs of the chair back on the stairs. The wheelchair adjusts the telescopic length of the telescopic joints of the front legs of the chair according to the stair step height difference between the front legs of the chair and the legs of the back of the chair. Make the front leg of the chair longer than the leg of the back of the chair, and the length of the leg of the front of the chair is equal to the height difference between the legs of the front of the chair and the leg of the back of the chair on the stairs. During the climbing process, always keep the seat of the wheelchair in a horizontal state to ensure the comfort and safety of the occupants. 4. The hexapod stair climbing wheelchair according to claim 1, characterized in that: the telescopic joints of the thighs and shanks of the three mechanical legs on the front side of the chair are realized by a ball screw nut mechanism, and the ball screw adopts a "fixed- "Free" type installation method, the fixed end is connected with the servo motor drive assembly through a two-way passive self-locking bearing, the nut mechanism is connected with the movable part of the telescopic leg, the shape of the movable part of the telescopic leg is a regular square prism, and there are 4 rolling rows on the four sides of the prism The guide rail block, the fixed part of the telescopic leg is a hollow regular prism, and there is a row of guide grooves on each of the 4 planes on its inner surface. Sliding, the telescopic part of the mechanical leg can be freely stretched and retracted under the drive of the servo motor to adjust the length of the mechanical leg, and prevent the ball screw from rotating in reverse under the force, so as to ensure the system's stability while realizing the telescopic function of the mechanical leg. safety. 5. The hexapod stair climbing wheelchair according to claim 1, characterized in that: the hip joints of the front side legs and the back side legs of the chair are installed in the power controller box through thrust bearings upwards, and are driven by servo motors. Drive, so that the chair front side legs and the chair back side legs can rotate around the vertical axis, so as to realize the steering operation of the hexapod stair climbing wheelchair system. 6. The hexapod stair climbing wheelchair according to claim 1, characterized in that: the ankle joints of the front side legs and the back side legs of the chair are equipped with joint bearings, and adopt the under-actuated scheme without motor drive, because The axis of the joint bearing can be deflected, and the feet of the six mechanical legs can be pitched up and down 20° around the left and right axis at the ankle joint, and can also be tilted 15° around the front and rear axis, so that the front legs of the chair and the chair The back and side legs can adapt to uneven ground, and it is convenient to walk in walking motion mode on potholes.