Non-circular Gear-Five-bar Mechanism Exoskeleton Rehabilitation Device for Knee Joint Rehabilitation

Abstract

The invention discloses a non-circular gear-five-bar mechanism exoskeleton rehabilitation device for knee joint rehabilitation, which comprises two exoskeleton mechanisms; the exoskeleton mechanism comprises a servo motor and a non-circular gear-five-bar mechanism; the non-circular gear-five-bar mechanism comprises a first non-circular gear, a second non-circular gear, a five-bar mechanism and a foot pedal; the five-bar mechanism comprises a crank, a transmission shaft, a first connecting rod, a connecting rod, a second connecting rod and a calf fixing plate. The invention drives the first non-circular gear by a servo motor, then drives the second non-circular gear, and realizes the motion trajectories of four pose points at the fixed position of the second connecting rod and the calf fixing plate through the variable-speed and variable-amplitude motion of the two non-circular gears meshing, so that the calf fixing plate drives the calf to make a reciprocating motion of first contracting and then flexing and extending relative to the thigh, and the knee joint reciprocates on a motion trajectory that is completely consistent with the shape of the four pose points and translates a certain distance, ensuring that the knee joint is trained according to the motion trajectory curve and posture angle change of a normal person's knee joint, and the rehabilitation effect is good.

Description

Technical Field

[0001] The invention belongs to the technical field of medical devices, and in particular relates to a non-circular gear-five-bar mechanism exoskeleton rehabilitation device for knee joint rehabilitation. Background Art

[0002] Stroke is also known as apoplexy or acute cerebrovascular disease. There are about 1.5 million new cases of stroke in China each year, and 85% of the patients suffer from hemiplegia. Medical research shows that stroke patients can restore limb motor function through scientific and reasonable rehabilitation training. Traditional rehabilitation training mainly relies on the highly skilled experience and skills of rehabilitation physicians and one-on-one manual training. It is difficult to achieve high-intensity, targeted and repetitive rehabilitation training requirements. The cost of rehabilitation training is also quite high, and the rehabilitation stage in the rehabilitation treatment process is relatively vague. Therefore, patients can use lower limb exoskeleton rehabilitation institutions to reduce the workload of rehabilitation physicians and reduce the cost of rehabilitation training. Through standardized repetitive exercises, they can exercise the lower limb muscles, stimulate the nervous system to control limb walking, and thus restore the motor function of the lower limbs.

[0003] As the largest and most complex joint in the human body, the knee joint is the primary functional component of the lower limbs. It supports standing when walking and provides power for movements such as going up and down stairs, standing up and squatting. Most of the existing human lower limb knee joint rehabilitation institutions are exoskeleton rehabilitation training robots. During the rehabilitation training process, usually only the flexion and extension rotation angle training of the knee joint is considered, and the gait of the human lower limb during normal walking is not considered. In addition, it has high requirements for human-computer information interaction and motion control. For this reason, such rehabilitation institutions are often expensive and cannot be widely popularized to individuals. Therefore, it is necessary to propose an exoskeleton rehabilitation device that can promote knee joint recovery and effectively improve the walking ability and daily activity ability of stroke patients, which has a knee joint motion trajectory and motion posture pattern that is closer to that of normal people during rehabilitation training. Summary of the invention

[0004] The purpose of the present invention is to provide a non-circular gear-five-bar mechanism exoskeleton rehabilitation device for knee joint rehabilitation in view of the shortcomings of existing lower limb knee joint rehabilitation mechanisms.

[0005] The present invention includes an outer frame and an exoskeleton mechanism; two exoskeleton mechanisms are symmetrically arranged on both sides of the outer frame. The exoskeleton mechanism includes a support frame, a servo motor, and a non-circular gear-five-bar mechanism; the support frame is fixed to the outer frame; the servo motor is fixed to the support frame and is controlled by a controller; the non-circular gear-five-bar mechanism includes a first non-circular gear, a second non-circular gear, a five-bar mechanism, and a foot pedal; the five-bar mechanism includes a crank, a transmission shaft, a first connecting rod, a connecting rod with a fixed end, a second connecting rod, and a calf fixing plate; the two transmission shafts are respectively supported on a spherical plain bearing with a housing, and both spherical plain bearings with housings are fixed to the support frame; one of the transmission shafts is connected to the output shaft of the servo motor through a coupling, and this transmission shaft is fixed to both the first non-circular gear and one end of the crank; the other transmission shaft is fixed to both the second non-circular gear and one end of the connecting rod with a fixed end, and the second non-circular gear meshes with the first non-circular gear; the other end of the crank is hinged to one end of the first connecting rod, and the other end of the first connecting rod is hinged to the triangular second connecting rod at the first angular position; the other end of the connecting rod with a fixed end is hinged to the second connecting rod at the second angular position; the second connecting rod is fixed to the upper end of the calf fixing plate at the third angular position; the lower end of the calf fixing plate is hinged to the foot pedal.

[0006] Preferably, it further includes a backrest assembly; the backrest assembly includes a wearable strap and a lumbar support; the lumbar support is fixed to the outer frame; the wearable strap is fixed to the lumbar support.

[0007] Preferably, the support frame includes a column and a mounting plate; the mounting plate is fixed to the column; the servo motor is fixed to the mounting plate through a servo motor mounting bracket; the spherical plain bearing with a housing is fixed to the column.

[0008] Preferably, a leg flexible strap is fixed to the inner side of the calf fixing plate.

[0009] Preferably, a foot flexible strap is fixed to the top surface of the foot pedal.

[0010] Preferably, the motion trajectory of the four pose points at the fixed position of the second connecting rod and the calf fixing plate is designed. The design process is as follows: Four pose points of the knee joint center during human walking are captured by a data acquisition system, denoted as points P1, P2, P3, and P4 respectively. Curve fitting is performed through these four pose points to obtain the motion trajectory of the four pose points at the fixed position of the second connecting rod and the calf fixing plate.

[0011] More preferably, when the fixed position of the second connecting rod and the calf fixing plate moves along the motion trajectory of the four pose points to the extreme position point P1, the calf flexes and extends relative to the thigh, and the calf fixing plate is in an upright state; when the fixed position of the second connecting rod and the calf fixing plate moves along the motion trajectory of the four pose points to the extreme position point P4, it is the extreme position where the calf contracts relative to the thigh, and the included angle between the calf fixing plate and the upright state is 40°.

[0012] More preferably, after one exoskeleton mechanism moves a set number of times, the other exoskeleton mechanism moves the set number of times; the two exoskeleton mechanisms move alternately several times.

[0013] The beneficial effects of the present invention are as follows:

[0014] 1. The non-circular gear-five-bar mechanism of the present invention is a planar mechanism with a single degree of freedom, which can meet the requirements of the movement trajectory and posture of the human knee joint, is more in line with the human gait standard, and has the advantages of simple structure, easy control, and good economy.

[0015] 2. The present invention can be in two modes: unilateral training (the two exoskeleton mechanisms move alternately) and bilateral simultaneous training (the two exoskeleton mechanisms move simultaneously) according to the rehabilitation situation of the patient; unilateral rehabilitation training is adopted in the early stage of rehabilitation training, and when the patient recovers to a certain stage, bilateral training is adopted to achieve better rehabilitation effects.

[0016] 3. During the rehabilitation training of the present invention, the backrest assembly fixedly supports the upper body of the human body, reduces the load borne by the legs, ensures safety during the rehabilitation training, and avoids the risk of the patient falling during the rehabilitation training; the waist support in the backrest assembly is used to support the waist of the person and reduce the large amplitude of the waist during training.

[0017] 4. During the knee joint rehabilitation training of the present invention, the non-circular gear one is driven by a servo motor, and then the non-circular gear two is driven. Through the variable speed and variable amplitude movement of the two meshing non-circular gears, the movement trajectory of the four pose points at the fixed position of the connecting rod two and the calf fixing plate in the five-bar mechanism is realized. Thus, the calf fixing plate drives the calf to make a reciprocating movement of first contracting and then stretching and bending relative to the thigh, and the knee joint center reciprocates on a movement trajectory that is exactly the same as the shape of the four pose points and is translated a certain distance, ensuring that the knee joint is trained according to the knee joint movement trajectory curve and posture angle change of a normal person. The training process perfectly conforms to ergonomics and has good rehabilitation effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic diagram of the overall structure of the present invention;

[0019] Figure 2 is a schematic diagram of the structure of the backrest assembly of the present invention;

[0020] Figure 3 is a schematic diagram of the structure of the exoskeleton mechanism of the present invention;

[0021] Figure 4 is a schematic diagram of the structure of the support frame of the present invention;

[0022] Figure 5 is a schematic diagram of the structure of the non-circular gear-five-bar mechanism of the present invention;

[0023] Figure 6 This is a schematic structural diagram of the five-bar mechanism in the present invention;

[0024] Figure 7 This is a motion attitude sketch of the crank, connecting rod one, rocker, and connecting rod two when the connecting rod two in the five-bar mechanism of the present invention and the fixed position of the calf fixing plate move along the motion trajectories of the four pose points to points P1, P2, P3, and P4;

[0025] Figure 8 This is a schematic diagram of the motion trajectories of the four pose points realized at the fixed position of the connecting rod two and the calf fixing plate in the five-bar mechanism of the present invention;

[0026] Figure 9 This is a schematic diagram of the attitude of the calf fixing plate at two extreme positions at the fixed position of the connecting rod two and the calf fixing plate in the present invention. Detailed implementation manners

[0027] The present invention will be further described below with reference to the accompanying drawings.

[0028] As Figure 1 shown, a non-circular gear-five-bar mechanism exoskeleton rehabilitation device for knee joint rehabilitation includes an outer frame 2 and an exoskeleton mechanism 3; the two exoskeleton mechanisms 3 are symmetrically arranged on both sides of the outer frame 2.

[0029] As Figure 3 、 Figure 4 、 Figure 5 and Figure 6As shown in the figure, the exoskeleton mechanism 3 includes a support frame 6, a servo motor 7, and a non-circular gear-five-bar mechanism 10; the support frame 6 is fixed to the outer frame 2; the servo motor 7 is fixed to the support frame 6 through a servo motor mounting bracket 8; the servo motor 7 is controlled by a controller; the non-circular gear-five-bar mechanism 10 includes a first non-circular gear 14, a second non-circular gear 15, a five-bar mechanism 16, and a foot pedal 17; the five-bar mechanism 16 includes a crank 18, a transmission shaft 19, a first connecting rod 20, a connecting rod 22, a second connecting rod 23, and a calf fixing plate 24; the two transmission shafts 19 are respectively supported on a spherical roller bearing with housing 21, and the two spherical roller bearings with housing 21 are both fixed to the support frame 6; one of the transmission shafts 19 is connected to the output shaft of the servo motor 7 through a coupling 9, and this transmission shaft 19 is fixed to both the first non-circular gear 14 and one end of the crank 18, so that the first non-circular gear 14 and the crank 18 rotate synchronously with this transmission shaft 19; the other transmission shaft 19 is fixed to both the second non-circular gear 15 and one end of the connecting rod 22, and the second non-circular gear 15 meshes with the first non-circular gear 14, so that the connecting rod 22 and this transmission shaft 19 rotate synchronously with the second non-circular gear 15; the other end of the crank 18 is hinged to one end of the first connecting rod 20, and the other end of the first connecting rod 20 is hinged to the triangular second connecting rod 23 at the first angular position; the other end of the connecting rod 22 is hinged to the second connecting rod 23 at the second angular position; the second connecting rod 23 is fixed to the upper end of the calf fixing plate 24 at the third angular position; through the transmission of the first non-circular gear 14 and the second non-circular gear 15, the crank 18 and the connecting rod 22 can rotate in opposite directions, with variable speed and variable amplitude, so that the second connecting rod 23 drives the calf fixing plate 24 to move in a predetermined designed posture; the lower end of the calf fixing plate 24 is hinged to the foot pedal 17.

[0030] As a preferred embodiment, as Figure 2 shown, it further includes a backrest assembly 1; the backrest assembly 1 includes a wearing strap 4 and a waist support 5; the waist support 5 is fixed to the outer frame 2; the wearing strap 4 is fixed to the waist support 5; the waist support 5 is used to support a person's waist and reduce the large amplitude of shaking of the waist during training.

[0031] As a preferred embodiment, as Figure 4 shown, the support frame 6 includes a column 12 and a mounting plate 13; the mounting plate 13 is fixed to the column 12; the servo motor mounting bracket 8 is fixed to the mounting plate 13; the spherical roller bearing with housing 21 is fixed to the column 12.

[0032] As a preferred embodiment, as Figure 3 shown, a leg flexible strap 11 is fixed to the inner side of the calf fixing plate 24, which is used to fix a person's calf and prevent the calf from moving during training, so as not to achieve the expected rehabilitation effect or even worsen the condition.

[0033] As a preferred embodiment, as Figure 5As shown, a foot flexible strap is fixed to the top surface of the foot pedal 17 for fixing the human foot sole.

[0034] As a preferred embodiment, as Figure 7 and Figure 8 shown, design the motion trajectory of the four pose points at the fixed position of the connecting rod two 23 and the calf fixing plate 24. The specific design process is as follows: Capture four pose points of the knee joint center during human walking through a data acquisition system, and mark them as points P1, P2, P3, and P4 respectively. Through curve fitting of these four pose points, obtain the motion trajectory of the four pose points at the fixed position of the connecting rod two 23 and the calf fixing plate 24, denoted as curve P1P4. After obtaining the motion trajectory of the four pose points, the pitch curves and tooth profiles of the non-circular gear one 14 and the non-circular gear two 15 can be further designed according to the motion trajectory of the four pose points, so that the finally output motion trajectory at the fixed position of the connecting rod two 23 and the calf fixing plate 24 is close to the motion trajectory of the four pose points.

[0035] The working principle of this non-circular gear-five-bar mechanism exoskeleton rehabilitation device for knee joint rehabilitation in the unilateral training (alternate movement of two exoskeleton mechanisms) mode is as follows:

[0036] 1. Fix the upper body of the patient through the backrest assembly 1, place the feet on the foot pedal 17, and make the calves fit the calf fixing plate 24 and fasten them with the leg flexible strap 11 to ensure safety during training and the correctness of training actions.

[0037] 2. Control the servo motor of an exoskeleton mechanism 3 by the controller to rotate forward and backward at a set speed (which can be 1 r / min); the rotation of the servo motor 7 drives the non-circular gear one 14 and the crank 18 to rotate synchronously, and the crank 18 then drives the connecting rod one 20 to rotate; the non-circular gear two 15 meshes with the non-circular gear one 14 to drive the connecting rod 22 to rotate synchronously; the connecting rod one 20 and the connecting rod 22 drive the two angular positions of the connecting rod two 23 respectively, so that the fixed position of the connecting rod two 23 and the calf fixing plate 24 reciprocates along the motion trajectory of the four pose points, that is, reciprocates along the curve P1P4 of the thick solid line part in Figure 8 (the curve of the thin solid line part is the motion trajectory other than the curve P1P4 when the servo motor rotates a full circle). This motion trajectory is basically the same as the actual motion trajectory of the knee joint center during normal human walking. And during the motion along this motion trajectory, since the connecting rod two 23 is fixed to the calf fixing plate 24, and the calf fixing plate 24 coincides with the posture position of the patient's calf, the calf fixing plate 24 drives the corresponding calf to move, so that the knee joint center can reciprocate on a motion trajectory that is exactly the same as the shape of the four pose points and translated a certain distance, and makes the calf make a movement of first contracting and then flexing and extending relative to the thigh, meeting the training requirements for the knee joint.

[0038] 3. After a set number of repetitions of training one calf, the servo motor in the exoskeleton mechanism 3 corresponding to that calf stops rotating. The servo motor of the other exoskeleton mechanism 3 is controlled by the controller to rotate forward and backward at a set speed, so as to drive the connecting rod two 23 of the exoskeleton mechanism 3 and the connecting position of the calf fixing plate 24 to reciprocate a set number of times along the motion trajectory of the four-position points, driving the corresponding calf to make a reciprocating motion of first contracting and then flexing and extending relative to the thigh a set number of times, and the center of the knee joint makes a reciprocating motion of a set number of times on a motion trajectory that is completely consistent with the motion shape of the four-position points and translated a certain distance. Finally, the servo motor in the exoskeleton mechanism 3 stops rotating.

[0039] 4. Repeat steps 2 and 3. After the two calves are alternately trained to reach a preset number of repetitions, the training ends.

[0040] When the connecting position of the connecting rod two 23 and the calf fixing plate 24 moves along the motion trajectory of the four-position points to points P1, P2, P3, and P4, the postures of the crank 18, the connecting rod one 20, the connecting rod 22, and the connecting rod two 23 are respectively as Figure 7 shown in (a), (b), (c), and (d). Figure 9 It shows the postures of the crank 18, the connecting rod one 20, the connecting rod 22, and the connecting rod two 23 when the connecting position of the connecting rod two 23 and the calf fixing plate 24 moves along the motion trajectory of the four-position points to two limit position points (points P1 and P4). Point P1 corresponds to the limit position of the calf flexing and extending relative to the thigh in a normal gait cycle. At this time, the calf fixing plate 24 is in an upright state. Point P4 corresponds to the limit position of the calf contracting relative to the thigh in a normal gait cycle. At this time, the included angle between the calf fixing plate 24 and the upright state reaches the maximum value (preferably, the maximum value of the included angle can be designed to be 40°).

[0041] In the bilateral simultaneous training (the two exoskeleton mechanisms move simultaneously) mode of this non-circular gear-five-bar mechanism exoskeleton rehabilitation device for knee joint rehabilitation, only need to combine steps 2 and 3 into one step, so that the servo motors of the two exoskeleton mechanisms 3 rotate forward and backward at a set speed simultaneously, and when one servo motor starts to rotate forward, the other servo motor starts to rotate backward, and when one servo motor starts to rotate backward, the other servo motor starts to rotate forward.

Claims

1. A non-circular gear-five bar mechanism exoskeleton rehabilitation device for knee joint rehabilitation, comprising an outer frame and an exoskeleton mechanism; two exoskeleton mechanisms are symmetrically arranged on both sides of the outer frame, and are characterized in that: The described exoskeleton mechanism includes a support frame, a servo motor, and a non-circular gear-five-bar mechanism; the support frame is fixed to the outer frame; the servo motor is fixed to the support frame and is controlled by a controller; the non-circular gear-five-bar mechanism includes a first non-circular gear, a second non-circular gear, a five-bar mechanism, and a foot pedal; the five-bar mechanism includes a crank, a transmission shaft, a first connecting rod, a rocker arm, a second connecting rod, and a calf fixing plate; the two transmission shafts are respectively supported on an outboard spherical bearing with pedestal, and both outboard spherical bearings with pedestal are fixed to the support frame; one of the transmission shafts is connected to the output shaft of the servo motor through a coupling, and this transmission shaft is fixed to both the first non-circular gear and one end of the crank; the other transmission shaft is fixed to both the second non-circular gear and one end of the rocker arm, and the second non-circular gear meshes with the first non-circular gear; the other end of the crank is hinged to one end of the first connecting rod, and the other end of the first connecting rod is hinged to the triangular second connecting rod at the first angular position; the other end of the rocker arm is hinged to the second connecting rod at the second angular position; the second connecting rod is fixed to the upper end of the calf fixing plate at the third angular position; the lower end of the calf fixing plate is hinged to the foot pedal.

2. The exoskeleton rehabilitation device with non-circular gear-five-bar mechanism for knee joint rehabilitation according to claim 1, wherein: It further includes a backrest assembly; the backrest assembly includes a wearing strap and a waist support; the waist support is fixed to the outer frame; the wearing strap is fixed to the waist support.

3. The non-circular gear-five bar mechanism exoskeleton rehabilitation device for knee joint rehabilitation according to claim 1, characterized in that: The support frame includes a column and a mounting plate; the mounting plate is fixed to the column; the servo motor is fixed to the mounting plate through a servo motor mounting bracket; the outboard spherical bearing with pedestal is fixed to the column.

4. The exoskeleton rehabilitation device of a non-circular gear-five bar mechanism for knee joint rehabilitation according to claim 1, characterized in that: A leg flexible strap is fixed to the inner side of the calf fixing plate.

5. The exoskeleton rehabilitation device with a non-circular gear-five-bar mechanism for knee joint rehabilitation according to claim 1, characterized in that: A foot flexible strap is fixed to the top surface of the foot pedal.

6. The non-circular gear-five bar mechanism exoskeleton rehabilitation device for knee joint rehabilitation according to any one of claims 1 to 5, characterized in that: Design the motion trajectory of the four pose points at the fixed position of the second connecting rod and the calf fixing plate. The specific design process is as follows: Capture the four pose points of the knee joint center during human walking through a data acquisition system, and record them as points P1, P2, P3, and P4 respectively. Perform curve fitting through these four pose points to obtain the motion trajectory of the four pose points at the fixed position of the second connecting rod and the calf fixing plate.

7. The exoskeleton rehabilitation device with a non-circular gear-five-bar mechanism for knee joint rehabilitation according to claim 6, characterized in that: When the fixed position of the second connecting rod and the calf fixing plate moves along the motion trajectory of the four pose points to the extreme position point P1, the calf flexes and extends relative to the thigh, and the calf fixing plate is in an upright state; when the fixed position of the second connecting rod and the calf fixing plate moves along the motion trajectory of the four pose points to the extreme position point P4, it is the extreme position where the calf contracts relative to the thigh, and the included angle between the calf fixing plate and the upright state is 40°.

8. The exoskeleton rehabilitation device with non-circular gear and five-bar mechanism for knee joint rehabilitation according to claim 7, characterized in that: After one exoskeleton mechanism moves a set number of times, the other exoskeleton mechanism moves a set number of times; the two exoskeleton mechanisms alternate in motion for several times.

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