Knee-ankle joint integrated active prosthesis and control method thereof

Abstract

The present invention relates to an active prosthesis with an integrated knee-ankle joint and a control method thereof. The active prosthesis comprises a knee joint, an ankle joint, a prosthesis support rod, a foot plate, a coaxially arranged knee joint drive source and an ankle joint drive source, wherein the knee joint drive source and the ankle joint drive source are arranged at the end of the prosthesis support rod away from the foot plate, wherein: the knee joint drive source is arranged at the rotation center of the knee joint, and the knee joint drive source drives the knee joint to rotate relative to the prosthesis support rod; the ankle joint drive source is combined with the ankle joint and the prosthesis support rod through a prosthesis connecting rod to form a four-bar structure, and the ankle joint drive source drives the ankle joint to rotate relative to the prosthesis support rod through the prosthesis connecting rod. The knee joint power unit and the ankle joint power unit of the present invention are coaxially arranged at the original knee joint position closer to the end of the patient's residual limb, and no power unit is arranged on the prosthesis support rod, so that the prosthesis support rod is lighter in weight and has a lower moment of inertia, thereby reducing the impact on the dynamic performance of the motion control system.

Description

Technical Field

[0001] The present invention relates to the technical field of prostheses, and in particular to an active prosthesis integrating a knee and ankle joint and a control method thereof. Background Art

[0002] Existing prosthetic joint mechanisms can be categorized as active, passive, and hybrid, depending on whether they provide a power source. Most traditional prosthetic limbs are passive. Passive prostheses lack any power source, requiring the user to provide the driving force to propel the prosthesis. This places a strain on the patient and makes walking and movement difficult. For disabled individuals, walking with these prostheses consumes 20% to 30% more energy than for healthy individuals, and movement between the healthy and affected limbs exhibits significant asymmetry. Hybrid and active knee-ankle prostheses utilize various power sources, such as motors, hydraulic cylinders, and reducers, to provide the speed and torque required for various human movements. However, these prostheses also present challenges such as complex mechanisms, heavy weight, high control difficulty, and high cost. Furthermore, most prostheses consist of a single knee or ankle joint, and few can achieve controller-controlled coordinated movement of the knee and ankle joints.

[0003] Existing active-passive hybrid and active knee-ankle prostheses generally use a motor + ball screw to provide power to the knee and ankle joints respectively, or use a reducer or a motor + ball screw + hydraulic cylinder to power the knee joint, and then use a passive form of elastic carbon fiber material and hydraulic damping to power the ankle joint. Both types of prostheses have the problems of complex structure, heavy weight, and high control difficulty. Moreover, no matter which form is adopted, an active or passive drive source needs to be set at the position of the ankle joint. In this way, when the amplitude of movement changes greatly, the moment of inertia is large. The moment of inertia is a parameter that directly affects the dynamic performance of the motion control system. The large amplitude of the moment of inertia has a greater impact on the dynamic performance of the motion control system. Summary of the Invention

[0004] To this end, the technical problem to be solved by the present invention is to overcome the shortcomings of the existing knee-ankle integrated prosthesis, such as complex structure, heavy weight and large moment of inertia, and to provide a knee-ankle integrated active prosthesis and a control method thereof, wherein the knee joint power unit and the ankle joint power unit are coaxially arranged at the original knee joint position closer to the patient's residual limb end, and no power unit is arranged on the prosthesis support rod, so that the prosthesis support rod is lighter and has a lower moment of inertia, thereby reducing the impact on the dynamic performance of the motion control system.

[0005] To solve the above technical problems, the present invention provides an integrated knee-ankle active prosthesis, comprising a knee joint, an ankle joint, a prosthesis support rod disposed between the knee joint and the ankle joint, and a foot plate connected to the ankle joint, and further comprising: a coaxially disposed knee joint drive source and an ankle joint drive source, wherein the knee joint drive source and the ankle joint drive source are disposed at the end of the prosthesis support rod away from the foot plate, wherein:

[0006] The knee joint driving source is arranged at the rotation center of the knee joint, and the knee joint driving source drives the knee joint to rotate relative to the prosthesis support rod;

[0007] The ankle joint driving source is combined with the ankle joint and the prosthetic limb support rod to form a four-bar structure. The ankle joint driving source drives the ankle joint to rotate relative to the prosthetic limb support rod through the four-bar structure.

[0008] In one embodiment of the present invention, a support assembly is further included, on which the knee joint drive source and the ankle joint drive source are both mounted, and the support assembly includes:

[0009] A supporting shell having a partition plate, with a knee joint drive source accommodating groove and an ankle joint drive source accommodating groove respectively provided on both sides of the partition plate;

[0010] A knee joint simply supported beam is provided on the side of the support shell, and the knee joint simply supported beam cooperates with the support shell to form a knee joint simply supported structure supporting the knee joint drive source;

[0011] An ankle joint simply supported beam is arranged on the other side of the support shell corresponding to the knee joint simply supported beam. The ankle joint simply supported beam cooperates with the support shell to form an ankle joint simply supported structure supporting the ankle joint driving source.

[0012] In one embodiment of the present invention, the knee joint drive source, the knee joint drive source and the ankle joint drive source are all electromagnetic drive structures, and the knee joint drive source and the ankle joint drive source each include a rotating magnetic steel sheet array, an electromagnetic coil, a gear disk, an eccentric structure, a drive output part, a fixing frame, a drive circuit board, and a control circuit board.

[0013] In one embodiment of the present invention, it also includes a coil power supply and a circuit board power supply, wherein the coil power supply respectively powers the electromagnetic coils in the knee joint drive source and the ankle joint drive source; the circuit board power supply respectively powers the drive circuit boards in the knee joint drive source and the ankle joint drive source.

[0014] In one embodiment of the present invention, a hollow wiring structure is further included, and the circuit wiring between the coil power supply and the circuit board power supply and the knee joint drive source and the ankle joint drive source all passes through the hollow wiring structure.

[0015] To solve the above technical problems, the present invention also provides a control method for an integrated active prosthesis of a knee and ankle joint, comprising the following steps:

[0016] Step S1, arranging a plurality of pressure sensors in an array on the plane where the bottom of the foot plate contacts the ground;

[0017] Step S2: Calculate the position of the plantar pressure center based on the positions and detected values ​​of the multiple pressure sensor groups to determine the current walking state of the foot;

[0018] Step S3: performing kinematic and dynamic analysis based on the walking state of the foot to determine the rotation angle, angular velocity, and angular acceleration of the knee and ankle joints in the current walking state;

[0019] Step S4: Calculate the joint control torque of the knee joint and ankle joint in the next walking state based on the angle, angular velocity and angular acceleration, and transmit the joint control torque to the drive circuit board to control the prosthesis to walk.

[0020] In one embodiment of the present invention, according to the actual walking situation, the walking state of the foot is divided into three walking support periods: heel touching the ground, whole foot flat, and toes touching the ground. In step S1, multiple groups of pressure sensors are divided into three areas: hindfoot, midfoot and forefoot according to the walking support period.

[0021] In one embodiment of the present invention, in step S2, the state of normal walking is first simulated to obtain the walking state of the foot during normal walking, through the process of the heel touching the ground, the whole foot flattening, and the toes touching the ground, and the triggering positions and detection thresholds of the pressure sensors in the three areas of the hindfoot, midfoot and forefoot are used to determine the moving trajectory of the plantar pressure center. During the control process, the triggering positions and detection values ​​of multiple groups of pressure sensors obtained by real-time detection are compared with the triggering positions and detection thresholds of the pressure sensors obtained during simulation to determine the walking state of the foot.

[0022] In one embodiment of the present invention, in step S3, a kinematic and dynamic model is established based on the correspondence between the movement morphology of the knee joint and ankle joint in the prosthesis and the walking state of the human body, so as to obtain the angle, angular velocity and angular acceleration of the rotation of the knee joint and ankle joint in the current walking state.

[0023] In one embodiment of the present invention, in step S4, the relationship between the joint torque and the angle, angular velocity, and angular acceleration variables of the knee and ankle joints during the change from the current state of the prosthesis to the next state can be determined based on the kinematic and dynamic models:

[0024] M(q)q'+C(q,q″)+G(q)=τ+τ d

[0025] Where q, q′ and q″ are angle, angular velocity and angular acceleration respectively;

[0026] τ, τ d is the control torque and disturbance torque;

[0027] M(q) is the inertia matrix of the lower limb prosthesis;

[0028] C(q) is the centrifugal force and the Coriolis force vector;

[0029] G(q) is the gravity vector.

[0030] The above technical solution of the present invention has the following advantages over the prior art:

[0031] The knee-ankle integrated active prosthesis of the present invention coaxially arranges the knee and ankle drive sources at the original knee joint position closer to the end of the patient's residual limb. Only the ankle joint for rotation and the foot plate for walking are arranged at the bottom of the prosthetic support rod, without any other power unit. This concentrates the mass of the entire prosthesis at the knee joint position, making the prosthetic support rod lighter. When controlling the rotation of the prosthetic support rod, its rotational inertia is lower, thereby reducing the impact on the dynamic performance of the motion control system and making the prosthetic support rod easier to control.

[0032] Furthermore, the coaxial arrangement of the knee joint drive source and the ankle joint drive source has another advantage: the rotation centers of the knee joint drive source and the ankle joint drive source are the same, and there is only one rotation center during rotation, and no rotation offset occurs;

[0033] In combination with the above-mentioned integrated active prosthesis of the knee and ankle joint, the present invention also provides a control method for an integrated active prosthesis of the knee and ankle joint, wherein a plurality of groups of pressure sensors are arranged on the contact surface of the footplate with the ground, and the contact position of the footplate with the ground is detected by the plurality of groups of pressure sensors, so as to judge the walking state of the prosthesis in the current state, and perform kinematic and dynamic analysis according to the current walking state of the prosthesis to determine the angle, angular velocity and angular acceleration of the rotation of the knee joint and ankle joint in the current walking state, and calculate the joint control torque of the knee joint and ankle joint in the next walking state according to the angle, angular velocity and angular acceleration, and transmit the joint control torque to the driving circuit board to control the walking of the prosthesis; the relative state of the contact between the footplate and the ground can be detected in real time by the plurality of groups of pressure sensors, and the control torque for driving the rotation of the prosthesis can be determined according to the real-time walking state, so that the control position of the prosthesis is more accurate and can be adjusted in real time according to the road conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments of the present invention in conjunction with the accompanying drawings, wherein

[0035] Figure 1 This is a schematic diagram of the overall structure of the integrated active prosthesis for the knee and ankle joint of the present invention;

[0036] Figure 2 It is a schematic diagram of the exploded structure of the support assembly of the present invention;

[0037] Figure 3 Schematic diagram of the internal structure of the knee joint drive source of the present invention;

[0038] Figure 4 Schematic diagram of the internal structure of the ankle joint drive source of the present invention;

[0039] Figure 5 is a flowchart of the steps of the control method of the integrated active prosthesis of the knee and ankle joint of the present invention;

[0040] Figure 6 It is the movement trajectory of the plantar pressure center of the present invention.

[0041] Explanation of the reference numerals in the specification: 1. knee joint; 2. ankle joint; 3. prosthetic support rod; 4. foot plate; 5. knee joint drive source; 51. knee joint rotating magnetic steel sheet array; 52. knee joint electromagnetic coil; 53. knee joint gear disc; 54. knee joint eccentric structure; 55. knee joint drive output member; 56. knee joint fixation frame; 57. knee joint drive circuit board; 58. coil power supply; 6. ankle joint drive source; 61. ankle joint rotating magnetic steel sheet array; 62. ankle joint electromagnetic coil; 63. ankle joint gear disc; 64. ankle joint eccentric structure; 65. ankle joint drive output member; 66. ankle joint fixation frame; 67. ankle joint drive circuit board; 7. prosthetic connecting rod; 8. support assembly; 81. support shell; 82. knee joint simply supported beam; 83. ankle joint simply supported beam; 84. knee joint end sealing cover; 85. ankle joint end sealing cover; 9. hollow wiring structure. DETAILED DESCRIPTION

[0042] The present invention will be further described below with reference to the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it. However, the embodiments are not intended to limit the present invention.

[0043] Example 1

[0044] Reference Figure 1As shown, the knee-ankle joint integrated active prosthesis of the present invention is used to simulate the position from the knee joint to the foot under the thigh, and is used to simulate the walking movement of the human body. It is suitable for rehabilitation use of patients after amputation. Therefore, the knee-ankle joint integrated active prosthesis of this embodiment includes a knee joint 1, an ankle joint 2, a prosthetic support rod 3 and a foot plate 4 required for walking. The prosthetic support rod 3 is arranged between the knee joint 1 and the ankle joint 2, connecting the knee joint 1 and the ankle joint 2 to simulate the calf. The foot plate 4 is connected to the ankle joint 2 and contacts the ground, which can simulate the sole of the foot walking on the ground.

[0045] Specifically, in order to achieve the simulated walking action, it is necessary to control the knee joint 1 and the ankle joint 2 to rotate. At this time, it is necessary to set a knee joint power output source and an ankle joint power output source to respectively drive the knee joint 1 and the ankle joint 2 to rotate. Generally, setting the knee joint power output source and the ankle joint power output source directly connected to the knee joint 1 and the ankle joint 2, and directly driving the joint rotation through the output end of the output source is the simplest and most easily thought of. The existing technology also uses this principle, and sets a knee joint drive source 5 and an ankle joint drive source 6 on the side of the knee joint 1 and the ankle joint 2 to drive the knee joint 1 and the ankle joint 2 to rotate. However, when actually using the simulated walking, it is found that such a setting will have certain problems:

[0046] First, the ankle joint 2 is arranged at the bottom end of the prosthetic support rod. If the ankle joint drive source 6 is arranged at this position, the weight borne by the prosthetic support rod 3 will inevitably increase, which will increase the moment of inertia of the prosthetic support rod 3 when it rotates. On the one hand, it is difficult to control the prosthetic support rod 3, and on the other hand, it also increases the load on the prosthetic support rod 3 and the knee joint drive source 5, affecting their service life.

[0047] Secondly, the knee joint driving source 5 and the ankle joint driving source 6 are set at different rotation centers. During the synchronous rotation process, the center of gravity will inevitably shift.

[0048] In order to solve the above problems, in this embodiment, on the basis of setting the components necessary for simulating walking, it also includes: a coaxially arranged knee joint drive source 5 and an ankle joint drive source 6, the knee joint drive source 5 and the ankle joint drive source 6 are arranged at the end of the prosthesis support rod 3 away from the foot plate 4, the knee joint drive source 5 and the ankle joint drive source 6 are coaxially arranged at the original knee joint position closer to the patient's residual limb end, only the ankle joint 2 for rotation and the foot plate 4 for walking are arranged at the bottom of the prosthesis support rod 3, and no other power unit is set, so that the mass of the entire prosthesis is concentrated at the knee joint 1 position, making the prosthesis support rod 3 lighter. When controlling the rotation of the prosthesis support rod 3, its rotational inertia is lower, thereby reducing the impact on the dynamic performance of the motion control system, making the prosthesis support rod 3 easier to control;

[0049] In addition, the coaxial arrangement of the knee joint drive source 5 and the ankle joint drive source 6 has another advantage: the rotation center of the knee joint drive source 5 and the ankle joint drive source 6 is the same, and there is only one rotation center during rotation, and no rotation offset occurs.

[0050] In combination with the positions of the above-mentioned knee joint drive source 5 and ankle joint drive source 6, in order to enable the knee joint drive source 5 and ankle joint drive source 6 to respectively drive the knee joint 1 and ankle joint 2 to rotate, the knee joint drive source 5 is set at the rotation center of the knee joint 1, and the knee joint drive source 5 drives the knee joint 1 to rotate relative to the prosthesis support rod 3; the ankle joint drive source 6 is combined with the ankle joint 2 and the prosthesis support rod 3 through the prosthesis connecting rod 7 to form a four-bar linkage structure, and the ankle joint drive source 6 drives the ankle joint 2 to rotate relative to the prosthesis support rod 3 through the four-bar linkage structure.

[0051] Reference Figure 1 and Figure 2 As shown, in order to coaxially arrange the knee joint drive source 5 and the ankle joint drive source 6 at the end of the prosthesis support rod 3, in this embodiment, a support assembly 8 is also included, and the knee joint drive source 5 and the ankle joint drive source 6 are both installed on the support assembly 8. The support assembly 8 includes: a support shell 81, a knee joint simply supported beam 82, and an ankle joint simply supported beam 83. The support shell 81 has a partition plate, and a knee joint drive source accommodating groove and an ankle joint drive source accommodating groove are respectively provided on both sides of the partition plate. The knee joint drive source 5 is placed in the knee joint drive source accommodating groove, and one side of the knee joint drive source 5 is fixed on On the supporting shell 81, the other side of the knee joint drive source 5 is fixed on the knee joint simply supported beam 82, and the knee joint simply supported beam 82 cooperates with the supporting shell 81 to form a knee joint simply supported structure supporting the knee joint drive source 5; similarly, the ankle joint drive source 6 is placed in the ankle joint drive source accommodating groove, one side of the ankle joint drive source 6 is fixed on the supporting shell 81, and the other side of the ankle joint drive source 6 is fixed on the ankle joint simply supported beam 83, and the ankle joint simply supported beam 83 cooperates with the supporting shell 81 to form an ankle joint simply supported structure supporting the ankle joint drive source 6.

[0052] Specifically, a knee joint end sealing cover 84 and an ankle joint end sealing cover 85 are respectively provided on the outer sides of the knee joint simply supported beam 82 and the ankle joint simply supported beam 83 .

[0053] In this embodiment, a knee joint drive source 5 is provided as a power source for rotating the knee joint 1 of the prosthesis, and power needs to be output according to actual needs. The top end of the knee joint 1 is connected to the thigh part of the amputee, and the knee joint drive source 5 can generate relative rotation under the support of the knee joint simply supported structure.

[0054] Reference Figure 3 As shown, the knee joint driving source 5 includes a knee joint rotating magnetic steel sheet array 51, a knee joint electromagnetic coil 52, a knee joint toothed disc 53, a knee joint eccentric structure 54, a knee joint driving output part 55, a knee joint fixing frame 56, and a knee joint driving circuit board 57. The knee joint driving source 3 serves as a power source for the prosthetic knee joint 1. The driving process is as follows: power is supplied to the knee joint electromagnetic coil 52 and the knee joint driving circuit board 57. After the knee joint electromagnetic coil 52 is energized, an electromagnetic field is generated, causing the knee joint rotating magnetic steel sheet array 51 to rotate. A transmission shaft is provided on the knee joint rotating magnetic steel sheet array 51, and a knee joint eccentric structure 54 is provided on the transmission shaft. A knee joint toothed disc 53 is provided on the outside of the knee joint eccentric structure 54. The electromagnetic coil 52 is energized to drive the knee joint rotating magnetic steel sheet array 51 to rotate, driving the knee joint gear disc 53 to perform eccentric movement; a through hole is provided on the knee joint gear disc 53, and an axial protrusion is provided on the knee joint fixing frame 56. The axial protrusion passes through the through hole on the knee joint gear disc 53, and the axial protrusion cooperates with the through hole to limit the relative rotation of the knee joint gear disc 53 when performing eccentric movement. The knee joint drive output member 55 is sleeved on the outside of the knee joint gear disc 53, and the interior of the knee joint drive output member 55 is provided with a tooth structure that meshes with the knee joint gear disc 53. When the knee joint gear disc 53 performs eccentric movement, it drives the knee joint drive output member 55 meshed with the knee joint gear disc 53 to perform deceleration movement, thereby driving the rotation of the knee joint 1.

[0055] Reference Figure 4As shown, the ankle joint driving source 6 includes an ankle joint rotating magnetic steel sheet array 61, an ankle joint electromagnetic coil 62, an ankle joint toothed disc 63, an ankle joint eccentric structure 64, an ankle joint driving output part 65, an ankle joint fixing frame 66, and an ankle joint driving circuit board 67. The ankle joint driving source 6 serves as a power source for the prosthetic ankle joint 2. The driving process is as follows: power is supplied to the ankle joint electromagnetic coil 62 and the ankle joint driving circuit board 67. When the ankle joint electromagnetic coil 62 is energized, an electromagnetic field is generated, so that the ankle joint rotating magnetic steel sheet array 61 rotates. A transmission shaft is provided on the ankle joint rotating magnetic steel sheet array 61, and an ankle joint eccentric structure 64 is provided on the transmission shaft. An ankle joint toothed disc 63 is provided on the outside of the ankle joint eccentric structure 64, and an ankle joint electromagnetic coil is provided on the outside of the ankle joint eccentric structure 64. The ring 62 is energized to drive the ankle joint rotating magnetic steel sheet array 61 to rotate, driving the ankle joint gear disc 63 to perform eccentric movement; a through hole is provided on the ankle joint gear disc 63, and an axial protrusion is provided on the ankle joint fixing frame 66. The axial protrusion passes through the through hole on the ankle joint gear disc 63, and the axial protrusion cooperates with the through hole to limit the relative rotation of the ankle joint gear disc 63 when performing eccentric movement. The ankle joint drive output member 65 is sleeved on the outside of the ankle joint gear disc 63, and the interior of the ankle joint drive output member 65 is provided with a tooth structure that meshes with the ankle joint gear disc 63. When the ankle joint gear disc 63 performs eccentric movement, it drives the ankle joint drive output member 65 that meshes with the ankle joint gear disc 63 to perform deceleration movement, thereby driving the rotation of the ankle joint 2 through the four-bar linkage structure.

[0056] Specifically, it also includes a control circuit board that provides control signals for the knee joint drive source 5 and the ankle joint drive source 6. In this embodiment, a coil power supply 58 and a circuit board power supply are also provided. The coil power supply 58 supplies power to the knee joint electromagnetic coil 52 and the ankle joint electromagnetic coil 62 respectively; the circuit board power supply supplies power to the control circuit board, and the control circuit board supplies power to the knee joint drive circuit board 57 and the ankle joint drive circuit board 67 respectively.

[0057] In this embodiment, a unified coil power supply 58 and a circuit board power supply 59 are provided to supply power to the knee joint drive source 5 and the ankle joint drive source 6 respectively. In order to facilitate the internal wiring, increase the overall aesthetics, and reduce the occurrence of accidents, refer to Figure 1 As shown, a hollow wiring structure 9 is also provided, and the circuit wiring between the coil power supply 58 and the circuit board power supply 59 and the knee joint driving source 5 and the ankle joint driving source 6 all pass through the hollow wiring structure 9.

[0058] Example 2

[0059] On the basis of the above embodiment 1, in order to realize the control of the prosthesis of embodiment 1, refer to Figure 5 As shown, this embodiment discloses a control method for an integrated active knee-ankle joint prosthesis, comprising the following steps:

[0060] Step S1, multiple groups of pressure sensors are arranged in an array on the plane where the bottom of the foot plate 4 contacts the ground;

[0061] Specifically, according to the actual walking situation, the walking state of the foot 4 is divided into three walking support periods: heel touching the ground, whole foot flat, and toes touching the ground. According to the walking support period, multiple groups of pressure sensors are divided into three areas: hindfoot, midfoot and forefoot.

[0062] Step S2: Calculate the position of the plantar pressure center based on the positions and detected values ​​of the multiple pressure sensor groups to determine the current walking state of the foot plate 4;

[0063] Specifically, first simulate the state of normal walking, establish a plane rectangular coordinate system when walking normally, place the footboard in the plane rectangular coordinate system, and refer to Figure 6 As shown, when the plantar pressure center COP is 60-100mm in the Y-axis direction, it is judged that the heel is touching the ground; when the plantar pressure center COP is 100-160mm in the Y-axis direction, it is judged that the whole foot is flat; when the plantar pressure center COP is 160-240mm in the Y-axis direction, it is judged that the toes are off the ground. In the process of the walking state of the sole 4 changing from heel touching the ground, whole foot flat, to toes touching the ground, the triggering positions and detection thresholds of the pressure sensors in the three areas of the hindfoot, midfoot and forefoot are detected to determine the moving trajectory of the plantar pressure center COP. In the actual control process, the triggering positions and detection values ​​of multiple groups of pressure sensors obtained by real-time detection are compared with the triggering positions and detection thresholds of the pressure sensors obtained in the simulation to determine the walking state of the sole 4.

[0064] Step S3: Perform kinematic and dynamic analysis based on the walking state of the foot 4. Based on the correspondence between the movement morphology of the knee joint 1 and ankle joint 2 in the prosthesis and the walking state of the human body, establish a kinematic and dynamic model to determine the rotation angle, angular velocity and angular acceleration of the knee joint 1 and ankle joint 2 in the current walking state.

[0065] Step S4: Calculate the joint control torque of the knee joint 1 and the ankle joint 2 in the next walking state based on the angle, angular velocity, and angular acceleration, and transmit the joint control torque to the drive circuit board to control the prosthesis to walk;

[0066] Specifically, the kinematic and dynamic models can determine the relationship between the joint torque and the angle, angular velocity, and angular acceleration variables of the knee joint 1 and ankle joint 2 during the change from the current state to the next state of the prosthesis:

[0067] M(q)q'+C(q,q″)+G(q)=τ+τ d

[0068] Where q, q′ and q″ are angle, angular velocity and angular acceleration respectively;

[0069] τ, τ d is the control torque and disturbance torque;

[0070] M(q) is the inertia matrix of the lower limb prosthesis;

[0071] C(q) is the centrifugal force and the Coriolis force vector;

[0072] G(q) is the gravity vector.

[0073] In this embodiment, multiple groups of pressure sensors are set on the surface where the footplate 4 contacts the ground. The contact position of the footplate 4 and the ground is detected by the multiple groups of pressure sensors, so as to judge the walking state of the prosthesis in the current state. Kinematic and dynamic analysis is then performed based on the current walking state of the prosthesis to determine the angle, angular velocity and angular acceleration of the rotation of the knee joint 1 and the ankle joint 2 in the current walking state. According to the angle, angular velocity and angular acceleration, the joint control torque of the knee joint 1 and the ankle joint 2 in the next walking state is calculated, and the joint control torque is transmitted to the drive circuit board to control the walking of the prosthesis. The relative state of the contact between the footplate 4 and the ground can be detected in real time by the multiple groups of pressure sensors, and the control torque for driving the rotation of the prosthesis is determined according to the real-time walking state, so that the control position of the prosthesis is more accurate and can be adjusted in real time according to the road conditions.

[0074] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. An integrated active prosthesis for the knee and ankle joint, comprising a knee joint, an ankle joint, a prosthetic support rod disposed between the knee joint and the ankle joint, and a foot plate connected to the ankle joint, characterized in that: Also includes: A coaxially arranged knee joint drive source and ankle joint drive source are provided at the end of the prosthetic support rod away from the foot plate, and only the ankle joint for rotation and the foot plate for walking are provided at the bottom of the prosthetic support rod, wherein: The knee joint driving source is arranged at the rotation center of the knee joint, and the knee joint driving source drives the knee joint to rotate relative to the prosthesis support rod; The ankle joint driving source is combined with the ankle joint and the prosthetic limb support rod to form a four-bar structure. The ankle joint driving source drives the ankle joint to rotate relative to the prosthetic limb support rod through the four-bar structure.

2. The integrated active knee-ankle joint prosthesis according to claim 1, characterized in that: It also includes a support assembly, on which the knee joint drive source and the ankle joint drive source are both mounted, and the support assembly includes: A supporting shell having a partition plate, with a knee joint drive source accommodating groove and an ankle joint drive source accommodating groove respectively provided on both sides of the partition plate; A knee joint simply supported beam is provided on the side of the support shell, and the knee joint simply supported beam cooperates with the support shell to form a knee joint simply supported structure supporting the knee joint drive source; An ankle joint simply supported beam is arranged on the other side of the support shell corresponding to the knee joint simply supported beam. The ankle joint simply supported beam cooperates with the support shell to form an ankle joint simply supported structure supporting the ankle joint driving source.

3. The integrated active knee-ankle prosthesis according to claim 1, characterized in that: The knee joint drive source, the knee joint drive source and the ankle joint drive source are all electromagnetic drive structures, and the knee joint drive source and the ankle joint drive source each include a rotating magnetic steel sheet array, an electromagnetic coil, a gear disk, an eccentric structure, a drive output part, a fixing frame, a drive circuit board and a control circuit board.

4. The integrated active knee-ankle joint prosthesis according to claim 3, characterized in that: It also includes a coil power supply and a circuit board power supply, wherein the coil power supply respectively supplies power to the electromagnetic coils in the knee joint drive source and the ankle joint drive source; and the circuit board power supply respectively supplies power to the drive circuit boards in the knee joint drive source and the ankle joint drive source.

5. The integrated active knee-ankle joint prosthesis according to claim 4, characterized in that: It also includes a hollow wiring structure, and the circuit wiring between the coil power supply and the circuit board power supply and the knee joint drive source and the ankle joint drive source all pass through the hollow wiring structure.

6. A control method for an integrated knee-ankle joint active prosthesis, for controlling the integrated knee-ankle joint active prosthesis according to any one of claims 1 to 5, characterized in that: The following steps are involved: Step S1, arranging a plurality of pressure sensors in an array on the plane where the bottom of the foot plate contacts the ground; Step S2: Calculate the position of the plantar pressure center based on the positions and detected values ​​of the multiple pressure sensor groups to determine the current walking state of the foot; Step S3: performing kinematic and dynamic analysis based on the walking state of the foot to determine the rotation angle, angular velocity, and angular acceleration of the knee and ankle joints in the current walking state; Step S4: Calculate the joint control torque of the knee joint and ankle joint in the next walking state based on the angle, angular velocity and angular acceleration, and transmit the joint control torque to the drive circuit board to control the prosthesis to walk.

7. The control method of the integrated knee-ankle active prosthesis according to claim 6, characterized in that: According to the actual walking situation, the walking state of the foot is divided into three walking support periods: heel landing, whole foot flat, and toes landing. In step S1, multiple groups of pressure sensors are divided into three areas: hindfoot, midfoot and forefoot according to the walking support period.

8. The control method of the integrated active knee-ankle joint prosthesis according to claim 7, characterized in that: In step S2, the state of normal walking is first simulated to obtain the positions and detection thresholds of the pressure sensors in the three areas of the hindfoot, midfoot and forefoot during normal walking, during which the walking state of the foot changes from the heel touching the ground, the whole foot flattening, and the toes touching the ground, and the moving trajectory of the plantar pressure center is determined. During the control process, the positions and detection values ​​of multiple groups of pressure sensors triggered by real-time detection are compared with the positions and detection thresholds of the pressure sensors triggered by the simulation to determine the walking state of the foot.

9. The control method of the integrated active knee-ankle joint prosthesis according to claim 6, characterized in that: In step S3, a kinematic and dynamic model is established based on the correspondence between the motion morphology of the knee and ankle joints in the prosthesis and the walking state of the human body, thereby obtaining the rotation angle, angular velocity and angular acceleration of the knee and ankle joints in the current walking state.

10. The control method of the integrated active knee-ankle joint prosthesis according to claim 9, characterized in that: In step S4, the relationship between the joint torque and the angle, angular velocity, and angular acceleration variables of the knee and ankle joints during the change from the current state to the next state of the prosthesis can be determined based on the kinematic and dynamic models: ； Among them, q, q' and q" are angle, angular velocity and angular acceleration respectively; τ, τ d is the control torque and disturbance torque; M(q) is the inertia matrix of the lower limb prosthesis; C(q) is the centrifugal force and the Coriolis force vector; G(q) is the gravity vector.

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