A flat ground walking cooperative control method of a hip-knee integrated intelligent artificial limb

Abstract

The application discloses a flat ground walking cooperative control method of hip-knee integrated intelligent artificial limbs and relates to the technical field of rehabilitation robot control. The method comprises the following steps: cooperative active assistance of hip and knee joints; cooperative compliant control of the hip and knee joints; the cooperative active assistance of the hip and knee joints comprises the following steps: gait phase division, the whole gait cycle is divided into a standing period, a pre-swing period and a swing period; tracking control of the maximum flexion swing angle of the hip joint under different walking speeds is provided when entering the pre-swing period; flexion compensation control of the maximum limit angle of the knee joint is provided after the pre-swing period ends; the cooperative compliant control of the hip and knee joints comprises the following steps: through joint damping regulation, different flexion damping torques are provided in the support period, the pre-swing period and the swing period. The application can ensure that the artificial limb can complete the stable walking task in cooperation with the amputee by imitating the mechanical impedance characteristics of the lower limbs and adapting to different speeds, and can effectively reduce the energy consumption of the artificial limb and save the walking energy of the human body.

Description

Technical Field

[0001] This invention relates to the field of rehabilitation robot control technology, and in particular to a method for coordinated control of hip and knee integrated intelligent prosthesis for walking on flat ground. Background Technology

[0002] Hundreds of thousands of people worldwide undergo lower limb amputations each year due to traffic accidents, workplace injuries, joint infections, bone tumors, and vascular disease complications. Current statistics indicate approximately 36 million people worldwide have lower limb amputations, of which about 2.2% are hip amputees. Hip amputations are considered high-level amputations, involving the loss of three joints on one leg, which significantly impacts daily activities and psychological well-being. Wearing a lower limb prosthesis can effectively mitigate these adverse effects.

[0003] However, traditional hip and knee prostheses are mostly biomimetic hydraulic damping systems, such as the patent "Control Method of Passive Prosthetic Knee Joint with Adjustable Damping" applied for by Ottobock Industries in 2007 and the patent "Artificial Lower Limb Hip Joint" applied for in 2001. These types of prostheses cannot provide power, so patients need to expend nearly twice the physical strength of normal people to complete walking. Furthermore, traditional lower limb prostheses are often unable to handle movement tasks in complex road conditions, thus greatly limiting their walking mobility.

[0004] Patents such as CN110169850B ("Control Method for Passive Hydraulic Knee Prosthesis"), CN111358602A ("A Hybrid Active-Passive Hydraulic Knee Prosthesis and Its Control Method and Application"), CN103750927B ("Adaptive Iterative Learning Control Method for Knee Joint of Lower Limb Prosthesis"), and CN107802384A ("A Control System and Control Method for Active Hip Joint Amputation Prosthesis") provide design schemes for control systems and control methods for independent joints of the lower limb. However, for hip amputees, there is currently no intelligent prosthesis that can achieve joint control of the hip and knee joints. Healthy individuals often require coordinated control of the hip and knee joints to achieve efficient weight transfer, especially on rough terrain. The coordinated cooperation of the hip and knee joints is the foundation for safe and stable walking. Due to the lack of coordination between the hip and knee joints, people who have undergone hip amputation are more prone to abnormal gait when walking, which leads to them expending more energy and increasing their risk of falling, thus limiting their daily activities.

[0005] Therefore, those skilled in the art are dedicated to developing a collaborative control method for flat walking of a hip-knee integrated intelligent prosthesis, which can improve the stable walking ability of hip amputees when wearing prostheses and reduce the power consumption of prosthesis operation and the energy consumption of amputees walking. Summary of the Invention

[0006] In view of the above-mentioned deficiencies of the prior art, the technical problem to be solved by the present invention is that when hip amputees walk on flat ground, the prosthetic hip and knee joints lack coordinated linkage control and the prosthesis lacks coordinated cooperation with the healthy leg.

[0007] To achieve the above objectives, the present invention provides a method for coordinated control of hip and knee integrated intelligent prosthesis for walking on flat ground, characterized in that the method includes: coordinated active assistance of hip and knee joints; and coordinated compliant control of hip and knee joints.

[0008] The coordinated active assistance of the hip and knee joints includes: gait phase segmentation, which divides the entire gait cycle into the stance phase, pre-swing phase, and swing phase; and coordinating the control of the hip and knee joints through phases of different gait cycles.

[0009] The phase-coordinated control of the hip and knee joints through different time-phase cycles includes: providing tracking control of the maximum flexion swing angle of the hip joint at different walking speeds during the pre-swing phase; and providing flexion compensation control of the maximum limit angle of the knee joint after the pre-swing phase.

[0010] The coordinated compliance control of the hip and knee joints includes providing different flexion damping torques during the support, pre-swing, and swing phases through joint damping adjustment.

[0011] Furthermore, the gait phase division includes: obtaining pelvic pose information through a posture sensor, using the temporal features of the pelvic pose information as input to a temporal convolutional network, determining the current gait phase of the finite state machine, and using this as the basis for switching control modes adopted by the prosthetic hip and knee joint controller.

[0012] Furthermore, the estimation of walking speed includes: solving for attitude estimation in a global coordinate system using data from the attitude sensor, and then calculating the transfer speed of the centroid, which reflects the walking speed of the human body.

[0013] Furthermore, the tracking control of the maximum flexion swing angle of the hip joint at different walking speeds during the pre-swing period includes: when the hip joint is in the active assistance phase of the pre-swing period, the hip joint drive motor is connected to the hip joint drive gear through the hip joint synchronization belt to provide the active torque required for raising the thigh when entering the pre-swing period. Based on the walking speed-maximum hip joint swing angle knowledge base, the maximum swing angle of the hip joint of the healthy leg corresponding to a specific walking speed is input, and the PD controller is used to realize the tracking of the position loop of the hip joint drive motor.

[0014] Furthermore, the flexion compensation control that provides the maximum limit angle of the knee joint after the pre-swing period includes: during the flexion phase after the pre-swing period, the knee joint drive motor provides active torque output, and the PD controller controls the knee joint flexion angle to approach the maximum limit angle, thereby realizing the compensation control of the prosthetic knee joint flexion.

[0015] Furthermore, the joint damping control includes: adjusting the opening of a rotary valve through a rotary motor in the hip joint variable damping hydraulic mechanism and the knee joint hydraulic-spring integrated variable mechanical resistance mechanism, thereby adjusting the pressure in the upper and lower oil chambers of the hip and knee joint hydraulic cylinders; changing the resistance of the hydraulic cylinder by adjusting the opening of the cylinder body and the external connection, causing a change in the damping magnitude of the hip and knee prosthetic joints to provide different flexion damping torques; during the support phase, adjusting the valve opening through the rotary motor to de-connect the hydraulic cylinder body with the outside; during the pre-swing and swing phases, adjusting the valve opening through the rotary motor to reach a preset value to connect the hydraulic cylinder body with the outside.

[0016] Furthermore, the preset value is obtained by searching the gait-damping mapping knowledge base to match the valve opening size corresponding to different gait speeds. If there is no corresponding relationship for the current gait speed in the gait-damping mapping knowledge base, the valve opening corresponding to the closest gait speed is used for adjustment, so that the prosthesis can adapt to the change in gait speed by changing the swing period duration.

[0017] Furthermore, the walking speed-maximum hip joint swing angle knowledge base is a knowledge base established during the rehabilitation training phase of amputees by recording the maximum swing angle of the unaffected leg of the prosthesis wearer at different walking speeds, thereby enabling the prosthesis hip joint to adapt to different walking speeds.

[0018] Furthermore, the walking speed-damping mapping knowledge base is established during the rehabilitation training phase of amputees by recording the valve opening during the hydraulic cylinder swinging and flexing process corresponding to the inherent walking habits of prosthese wearers at different walking speeds. This knowledge base establishes the mapping relationship between the two, enabling the prosthesis to adapt to different walking speeds.

[0019] Furthermore, the attitude sensor is embedded in the prosthesis socket waist belt connector near the amputee's center of gravity during transfer.

[0020] In the task of walking on flat ground with the assistance of the prosthesis and the unaffected leg of the amputee, the present invention activates the active drive motor of the hip joint during the hip flexion phase of the pre-swing period to increase the range of motion of the hip joint of the prosthesis, and activates the active drive motor of the knee joint during the knee flexion phase at the end of the pre-swing period to assist in stepping, thereby realizing active coordinated assistance of the two joints of the prosthesis. The invention coordinates the coordinated movement of the hip and knee joints based on the changing law of the mechanical impedance characteristics of the prosthesis joints during flat ground walking.

[0021] The hip joint active drive motor in the integrated hip and knee intelligent prosthesis provides active torque to lift the thigh during the pre-swing phase of hip flexion when walking on flat ground, and adjusts the magnitude of active torque by matching different walking speeds. During the standing phase, the locking hydraulic valve enables the variable damping hydraulic mechanism to provide a larger damping torque to ensure stability, while during the swing phase, the variable damping hydraulic mechanism provides a smaller damping torque, and the damping torque is adjusted by the gait-damping mapping knowledge base to adapt to different walking speeds. The variable stiffness spring mechanism enhances the flexibility of the linkage mechanism to ensure the biomimetic nature of the prosthesis's movement.

[0022] The active drive motor of the knee joint in the integrated hip-knee intelligent prosthesis provides active torque to the knee joint flexion stage at the end of the pre-swing phase when the prosthesis is walking on flat ground, reaching the maximum limit angle to cooperate with the hip joint to complete the step. During the standing phase, the locking hydraulic valve enables the variable damping hydraulic mechanism to provide a larger damping torque to ensure stability, while during the swing phase, the variable damping hydraulic mechanism provides a smaller damping torque. The damping torque is adjusted by the gait-damping mapping knowledge base to adapt to different walking speeds. The variable stiffness spring mechanism enhances the flexibility of the linkage mechanism to ensure the biomimetic nature of the prosthesis's movement.

[0023] Compared with the prior art, the present invention has at least the following beneficial technical effects:

[0024] In addition to providing an active assist control mode that coordinates the hip and knee joints, this invention can also achieve biomimetic coordinated compliant control through a variable damping hydraulic mechanism and a variable stiffness spring mechanism in the hip and knee joints. The biomimetic regulation mechanism of the prosthesis's mechanical impedance characteristics introduced in this invention can ensure that the prosthesis can counteract the additional forces and external interference it experiences during walking, and enhance the prosthesis's adaptability to different walking speeds through a pre-built gait knowledge base, thereby ensuring that the prosthesis can cooperate with amputees to complete stable walking tasks.

[0025] Since it does not require active assistance throughout the gait cycle, but relies solely on the lower-power adjustable motors in the variable stiffness and variable damping mechanisms to provide compliant control in a fixed pattern, the control method adopted can effectively reduce prosthesis energy consumption and save human walking energy while improving the walking performance of the prosthesis in conjunction with the amputee's healthy leg.

[0026] The following will further explain the concept, specific structure, and technical effects of the present invention in conjunction with the accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the overall control scheme module of a preferred embodiment of the present invention;

[0028] Figure 2This is a schematic diagram of the left side structure of a preferred embodiment of the hip-knee integrated intelligent prosthesis of the present invention;

[0029] Figure 3 This is a schematic diagram of the right side structure of a preferred embodiment of the hip-knee integrated intelligent prosthesis of the present invention;

[0030] Figure 4 This is a block diagram of a control system for coordinated active assistance of the hip and knee joints according to a preferred embodiment of the present invention;

[0031] Figure 5 This is a block diagram of a control system for coordinated compliance control of the hip and knee joints, according to a preferred embodiment of the present invention.

[0032] Among them, 1-hip joint drive gear; 2-hip joint timing belt; 3-hip joint drive motor; 4-hip joint variable damping hydraulic mechanism; 5-hip joint variable stiffness spring mechanism; 6-knee joint drive motor; 7-four-bar linkage; 8-knee joint hydraulic-spring integrated variable mechanical impedance mechanism; 9-main control board; 10-attitude sensor. Detailed Implementation

[0033] The following description, with reference to the accompanying drawings, illustrates several preferred embodiments of the present invention to make its technical content clearer and easier to understand. The present invention can be embodied in many different forms, and the scope of protection of the present invention is not limited to the embodiments mentioned herein.

[0034] In the accompanying drawings, components with the same structure are indicated by the same numerical designation, and components with similar structures or functions are indicated by similar numerical designations. The dimensions and thicknesses of each component shown in the drawings are arbitrary, and the present invention does not limit the dimensions and thicknesses of each component. To make the illustrations clearer, the thickness of some components has been appropriately exaggerated in the drawings.

[0035] like Figure 1 The diagram shown is a schematic representation of the overall control scheme module of a preferred embodiment of the present invention. The control method for walking on flat ground includes:

[0036] Step 1: Coordinated active assistance from the hip and knee joints;

[0037] Step 2: Coordinated and compliant control of the hip and knee joints.

[0038] The coordinated control of the hip and knee joints is achieved by matching the gait phase of the prosthesis as the controller input of the independent joint active drive motor in the active mode of the integrated hip and knee prosthesis, and then combining the variation pattern of mechanical impedance of healthy people walking on flat ground under different gait phases as the basis for adjusting the motor in the independent joint variable mechanical impedance mechanism in the passive mode of the integrated hip and knee prosthesis, so as to achieve the purpose of coordinated control.

[0039] The hip and knee joint assistance requirements of integrated hip-knee prostheses are as follows:

[0040] (1) During the pre-swing period, the prosthetic hip joint needs to provide active assistance to achieve efficient transfer of the amputee's center of gravity.

[0041] (2) After the pre-swing period, the prosthetic knee joint needs to provide active assistance to achieve effective control of the prosthetic step.

[0042] The mechanical impedance characteristics of the hip and knee joints in an integrated hip-knee prosthesis are as follows:

[0043] (1) In the standing phase, the hip and knee joints of the prosthesis need to provide sufficiently high damping torque to ensure walking stability;

[0044] (2) During the swing phase, it is necessary to enhance the flexibility of the prosthesis, that is, the hip and knee joints of the prosthesis need to provide a lower intensity of damping torque and allow the prosthesis to adapt to different walking speeds;

[0045] (3) Throughout the gait cycle, the flexibility of the linkage mechanism needs to be enhanced by the variable stiffness mechanism of the hip and knee joints to ensure the bionic nature of the prosthesis movement.

[0046] like Figure 2 , Figure 3 The diagram shows the left and right side structures of the integrated hip and knee smart prosthesis of this embodiment. The integrated hip and knee prosthesis is a hybrid active and passive drive type prosthesis. The components related to motion control mainly include a hip joint drive gear 1, a hip joint timing belt 2, a hip joint drive motor 3, a hip joint variable damping hydraulic mechanism 4, a hip joint variable stiffness spring mechanism 5, a knee joint drive motor 6, a four-bar linkage 7, a knee joint hydraulic-spring integrated variable mechanical impedance mechanism 8, a main control board 9, and a posture sensor 10.

[0047] When the amputee is in a flat walking mode, during the pre-swing phase of the gait cycle, the hip joint drive motor 3 needs to be turned on via the main control board 9 during the active hip joint assistance period. After the pre-swing phase, the knee joint drive motor 6 needs to be turned on via the main control board 9 during the active knee joint assistance period. During other periods, the hip joint drive motor 3 and the knee joint drive motor 6 remain off, while the variable damping hydraulic mechanism 4 of the hip joint and the variable damping adjustment motor in the integrated hydraulic-spring variable mechanical impedance mechanism 8 of the knee joint remain on, and the variable stiffness adjustment motor in the variable stiffness spring mechanism 5 of the hip joint and the integrated hydraulic-spring variable mechanical impedance mechanism 8 of the knee joint remains off.

[0048] In this embodiment, the hip joint drive motor 3 provides active assistance to the hip joint of the prosthesis when the prosthesis enters the pre-swing period, and the knee joint drive motor 6 provides auxiliary assistance to the knee joint of the prosthesis after the pre-swing period ends. At the same time, the compliant and coordinated control is achieved by relying on the impedance characteristics of the hip joint variable damping hydraulic mechanism 4, the hip joint variable stiffness spring mechanism 5, and the knee joint hydraulic-spring integrated variable mechanical impedance mechanism 8. This method mainly focuses on controlling the variable damping hydraulic mechanism of the hip joint variable damping hydraulic mechanism 4 and the knee joint hydraulic-spring integrated variable mechanical impedance mechanism 8, while the variable stiffness spring, as a joint energy transfer buffer component, enhances the flexibility of the linkage mechanism to ensure the biomimetic nature of the prosthesis movement.

[0049] In this embodiment, the posture sensor 10 is embedded in the prosthesis socket waist belt connector near the amputee's center of mass transfer position, which can realize gait phase segmentation and walking speed estimation.

[0050] Specifically, one method for gait phase segmentation is as follows: A six-axis IMU embedded in the prosthesis socket's waist belt connector, near the amputee's center of mass transfer, acquires data to detect pelvic motion in three-dimensional space. Then, a real-time sliding window captures the six-axis IMU data and calculates the temporal features of each axis. This data is then input into a temporal convolutional network (TCN) to determine the current gait phase of the finite state machine, which serves as the basis for switching control modes by the prosthetic hip and knee joint controllers. The sliding window length is 200 ms, with a 50% overlap rate. The features are a 24-dimensional matrix composed of the average, standard deviation, maximum, and minimum values ​​calculated from the six-axis data within the sliding window.

[0051] The gait cycle is divided into three phases: the standing phase, the pre-swing phase, and the swing phase.

[0052] Specifically, one method for estimating walking speed is to use data from a six-axis IMU located near the amputee's center of mass to perform attitude estimation in a global coordinate system, and then calculate the transfer speed of the center of mass.

[0053] To achieve the transformation between the body coordinate system and the global coordinate system, we first need to solve for the rotation matrix, as follows:

[0054] Angular velocity ω directly measured by the IMU's three-axis gyroscope b (t)=[ω bx (t),ω by (t),ω bz (t)] T Construct Ω(t):

[0055]

[0056] The rotation matrix representing the pose is solved in real time using the rectangular numerical integration method. Where C(0) represents the initial pose.

[0057] Walking speed is estimated based on attitude estimation.

[0058] Based on the observations of the IMU's triaxial accelerometer at time t, a b (t)=[a bx (t),a by (t),a bz (t)] T This is used to calculate the speed at which the centroid coordinates shift in the global coordinate system, which reflects the walking speed of the human body.

[0059] First, the acceleration in the body coordinate system is transformed to the global coordinate system, which can be expressed by the following formula:

[0060] a g =Ca b

[0061] Then, subtracting gravity from the acceleration and performing rectangular numerical integration on the remaining acceleration yields the centroid transfer velocity in the global coordinate system, which can be expressed as follows:

[0062]

[0063] Among them, v g (0) represents the initial velocity of the device, g g It is the gravitational acceleration vector in the global coordinate system.

[0064] like Figure 4 As shown, one method for implementing coordinated active assistance of the hip and knee joints in step 1 is described below:

[0065] When the hip joint is in the active assist phase of the pre-swing period, the hip joint drive motor 3 is connected to the hip joint drive gear 1 through the hip joint timing belt 2 to provide the active torque required for the hip joint to lift the thigh when entering the pre-swing period. By inputting the maximum swing angle of the hip joint of the healthy leg corresponding to a specific walking speed, the PD controller realizes the tracking of the position loop of the hip joint drive motor 3.

[0066] The gait-maximum hip swing angle knowledge base is a knowledge base established during the rehabilitation training phase of amputees by recording the maximum swing angle of the unaffected leg of the prosthesis wearer at different walking speeds.

[0067] The knee joint drive motor 6 provides active torque output during the flexion phase at the end of the pre-swing period. The PD controller controls the knee joint flexion angle to approach the maximum limit angle, thereby achieving compensatory control of the prosthetic knee joint flexion.

[0068] The PD control law for the active motor drive of the prosthetic hip and knee joints is as follows:

[0069] τ=k p (a t -p t )-k d v t

[0070] Where τ represents the control torque applied to the hip and knee joints of the prosthesis, a t p represents the target tracking angle of the prosthetic hip and knee joints at the current moment. t This indicates the actual measured angles of the hip and knee joints of the prosthesis at the current moment, v t This represents the actual measured joint velocities of the prosthetic hip and knee joints at the current moment, k. p and k d Indicates adjustable gain, k p The value range is 50–500, k d The value is set to 0.5k. p .

[0071] like Figure 5 As shown, a method for implementing coordinated compliant control of the hip and knee joints in step 2 is described below:

[0072] During the support phase, the hip and knee joints provide high damping torque: the valve opening is adjusted by a rotary motor, so that the hydraulic cylinder is no longer connected to the outside.

[0073] During the pre-swing and swing phases, the prosthetic hip and knee joints need to provide a small flexion damping torque: the valve opening is adjusted by a rotary motor to reach a preset value, so that the hydraulic cylinder is connected to the outside.

[0074] Joint damping adjustment is achieved by adjusting the opening of the rotary valve through the rotary motor of the hip joint variable damping hydraulic mechanism 4 and the opening of the rotary valve through the rotary damping hydraulic mechanism of the knee joint hydraulic-spring integrated variable mechanical resistance mechanism 8. This adjusts the pressure of the upper and lower oil chambers of the hip and knee joint hydraulic cylinders. By adjusting the opening of the cylinder body and the external connection, the resistance of the hydraulic cylinder is changed, thereby causing a change in the damping magnitude of the hip and knee prosthetic joints.

[0075] The preset value is achieved by searching the gait-damping mapping knowledge base to match the valve opening size corresponding to different gait speeds. If there is no corresponding relationship for the current gait speed in the knowledge base, the valve opening corresponding to the closest gait speed is used for adjustment, so that the prosthesis can adapt to changes in gait speed by changing the swing period duration.

[0076] The gait-damping mapping knowledge base is a knowledge base established during the rehabilitation training phase of amputees by recording the valve opening during the swinging and flexing process of the hydraulic cylinder corresponding to the inherent walking habits of prosthese users at different walking speeds, which is the absolute operating position of the stepper motor.

[0077] This embodiment introduces a biomimetic control mechanism that incorporates the mechanical impedance characteristics of the prosthesis to match the changing patterns of human walking. This ensures that the prosthesis can counteract the additional forces and external interference it experiences during walking, thereby enabling the prosthesis to assist amputees in completing stable walking tasks.

[0078] By detecting the phase of human gait, active assist control of the hip and knee joints is achieved based on a finite state machine; by adjusting the hydraulic damping of the hip and knee joints to a locked or variable mode, the prosthesis can achieve compliant and coordinated control through the impedance characteristics of the variable damping hydraulic mechanism and variable stiffness spring mechanism of the hip and knee joints; and the prosthesis's adaptability to different walking speeds is provided through a pre-built knowledge base of gait speed-maximum hip joint swing angle and gait speed-damping mapping.

[0079] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A method for coordinated control of hip-knee integrated intelligent prosthesis for walking on flat ground, characterized in that, The method includes: coordinated active assistance of the hip and knee joints; coordinated compliant control of the hip and knee joints; The coordinated active assistance of the hip and knee joints includes: gait phase segmentation, which divides the entire gait cycle into the stance phase, pre-swing phase, and swing phase; and phase coordination of hip and knee joint control through different gait cycles. The phase-coordinated control of the hip and knee joints through different time-phase cycles includes: providing tracking control of the maximum flexion swing angle of the hip joint at different walking speeds during the pre-swing phase; and providing flexion compensation control of the maximum limit angle of the knee joint after the pre-swing phase. The coordinated compliance control of the hip and knee joints includes: providing different flexion damping torques during the support, pre-swing, and swing phases through joint damping adjustment; Throughout the gait cycle, during the pre-swing phase, the main control board activates the hip joint drive motor during the active hip joint assistance phase. After the pre-swing phase, the main control board activates the knee joint drive motor during the active knee joint assistance phase. During other phases, both the hip and knee joint drive motors remain off. Meanwhile, the variable damping adjustment motors in the hip joint variable damping hydraulic mechanism and the knee joint hydraulic-spring integrated variable mechanical impedance mechanism remain on, while the variable stiffness adjustment motors in the hip joint variable stiffness spring mechanism and the knee joint hydraulic-spring integrated variable mechanical impedance mechanism remain off. The hip joint drive motor provides active torque to elevate the thigh during the pre-swing phase of the prosthesis's walking on flat ground, and adjusts the magnitude of the active torque by matching different walking speeds. During the standing phase, the locking hydraulic valve enables the variable damping hydraulic mechanism to provide a larger damping torque to ensure stability, while during the swing phase, the variable damping hydraulic mechanism provides a smaller damping torque, and the damping torque is adjusted by the gait-damping mapping knowledge base to adapt to different walking speeds. The variable stiffness spring mechanism enhances the flexibility of the linkage mechanism to ensure the biomimetic nature of the prosthesis's movements. The knee joint drive motor provides active torque to the knee joint flexion phase at the end of the pre-swing phase when the prosthesis is walking on flat ground, reaching the maximum limit angle to cooperate with the hip joint to complete the step. During the standing phase, the locking hydraulic valve enables the variable damping hydraulic mechanism to provide a larger damping torque to ensure stability, while during the swing phase, the variable damping hydraulic mechanism provides a smaller damping torque. The damping torque is adjusted by the gait-damping mapping knowledge base to adapt to different walking speeds. The variable stiffness spring mechanism enhances the flexibility of the linkage mechanism to ensure the biomimetic nature of the prosthesis's movement. The joint damping control includes: adjusting the opening of a rotary valve through a rotary motor in the hip joint variable damping hydraulic mechanism and the knee joint hydraulic-spring integrated variable mechanical resistance mechanism, thereby adjusting the pressure in the upper and lower oil chambers of the hip and knee joint hydraulic cylinders; changing the resistance of the hydraulic cylinder by adjusting the opening of the cylinder body and the external connection, causing changes in the damping magnitude of the hip and knee prosthetic joints to provide different flexion damping torques; during the support phase, adjusting the valve opening through the rotary motor to de-connect the hydraulic cylinder body to the outside; during the pre-swing and swing phases, adjusting the valve opening through the rotary motor to reach a preset value to connect the hydraulic cylinder body to the outside.

2. The method for coordinated control of hip-knee integrated intelligent prosthesis for walking on flat ground as described in claim 1, characterized in that, The gait phase division includes: obtaining pelvic pose information through a posture sensor, using the temporal features of the pelvic pose information as input to a temporal convolutional network, determining the current gait phase of the finite state machine, and using this as the basis for switching control modes adopted by the prosthetic hip and knee joint controller.

3. The method for coordinated control of hip-knee integrated intelligent prosthesis for walking on flat ground as described in claim 2, characterized in that, The estimation of walking speed includes: solving the attitude estimation in the global coordinate system using the data from the attitude sensor, and calculating the transfer speed of the centroid point based on the attitude estimation, which reflects the walking speed of the human body.

4. The method for coordinated control of hip-knee integrated intelligent prosthesis for walking on flat ground as described in claim 1, characterized in that, The tracking control of the maximum flexion swing angle of the hip joint at different walking speeds during the pre-swing phase includes: when the hip joint is in the active assistance phase of the pre-swing phase, the hip joint drive motor is connected to the hip joint drive gear through the hip joint synchronization belt to provide the active torque required for raising the thigh when entering the pre-swing phase. Based on the walking speed-maximum hip joint swing angle knowledge base, the maximum swing angle of the hip joint of the healthy leg corresponding to a specific walking speed is input, and the PD controller is used to realize the tracking of the position loop of the hip joint drive motor.

5. The method for coordinated control of hip-knee integrated intelligent prosthesis for walking on flat ground as described in claim 1, characterized in that, The flexion compensation control that provides the maximum limit angle of the knee joint after the pre-swing period includes: during the flexion phase after the pre-swing period, the knee joint drive motor provides active torque output, and the PD controller controls the knee joint flexion angle to approach the maximum limit angle, thereby realizing the compensation control of the prosthetic knee joint flexion.

6. The method for coordinated control of hip-knee integrated intelligent prosthesis for walking on flat ground as described in claim 1, characterized in that, The preset value is obtained by searching the gait-damping mapping knowledge base to match the valve opening size corresponding to different gait speeds. If there is no corresponding relationship for the current gait speed in the gait-damping mapping knowledge base, the valve opening corresponding to the closest gait speed is used for adjustment, so that the prosthesis can adapt to the change in gait speed by changing the swing period duration.

7. The method for coordinated control of hip-knee integrated intelligent prosthesis for flat ground walking as described in claim 4, characterized in that, The aforementioned walking speed-maximum hip swing angle knowledge base is a knowledge base established during the rehabilitation training phase of amputees by recording the maximum swing angle of the unaffected leg of the prosthesis wearer at different walking speeds, thus enabling the prosthesis hip joint to adapt to different walking speeds.

8. The method for coordinated control of hip-knee integrated intelligent prosthesis for flat ground walking as described in claim 6, characterized in that, The aforementioned gait-damping mapping knowledge base is established during the rehabilitation training phase of amputees by recording the valve opening during the hydraulic cylinder swinging and flexing process corresponding to the inherent walking habits of prosthese wearers at different walking speeds. This knowledge base establishes the mapping relationship between the two, enabling the prosthesis to adapt to different walking speeds.

9. The method for coordinated control of hip-knee integrated intelligent prosthesis for walking on flat ground as described in claim 2, characterized in that, The attitude sensor is embedded in the prosthesis socket waist belt connector near the amputee's center of gravity during transfer.

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