Flexible hip joint power-assisted exoskeleton and control method thereof

Abstract

This invention relates to a flexible hip joint assistive exoskeleton and its control method. The exoskeleton includes a posterior drive unit, a right anterior drive unit, a left anterior drive unit, a left posterior Bowden line, a right posterior Bowden line, a left knee joint flexible binding structure, a right knee joint flexible binding structure, a flexible bionic vest, a left anterior flexible band, and a right anterior flexible band. The left posterior Bowden line connects the posterior drive unit and the left knee joint flexible binding structure, and the right posterior Bowden line connects the posterior drive unit and the right knee joint flexible binding structure. The posterior drive unit controls the tightening and releasing of the two Bowden lines. The left anterior flexible band connects the left anterior drive unit and the left knee joint flexible binding structure, and the right anterior flexible band connects the right anterior drive unit and the right knee joint flexible binding structure. The two anterior drive units control the tightening and releasing of their respective flexible bands. Through the cooperation of the flexible bands and Bowden lines, the exoskeleton assists in hip joint flexion and extension. The method controls the exoskeleton through dual-layer sensing technology. The upper layer of sensing uses multi-sensor data to identify the timing of exoskeleton assistance, while the lower layer of control uses a dual-modal switching control strategy to achieve coordinated control of the tightening and releasing of Bowden lines or flexible belts.

Description

Technical Field

[0001] This invention belongs to the field of lower limb assistive exoskeleton technology, specifically a flexible hip joint assistive exoskeleton and its control method. Technical Background

[0002] Lower limb assistive exoskeletons can be divided into rigid exoskeletons and flexible exoskeletons. Rigid exoskeletons can assist hip and knee joint movement while also providing support and weight-bearing, transferring the weight of supported objects to the ground and reducing the wearer's load. However, rigid exoskeletons have drawbacks such as difficulty in aligning the joint center with the human body's joint center and poor flexibility, resulting in greater human-machine interaction forces and affecting wearing comfort. Flexible exoskeletons, on the other hand, have gained more attention because they overcome the shortcomings of rigid exoskeletons, providing assistance to the wearer while offering good wearing comfort.

[0003] In recent years, researchers have conducted in-depth studies on flexible exoskeletons, exoskeleton-assisted phase recognition, and human motion pattern recognition. Kyushu University in Japan has developed a flexible lower limb exoskeleton made of flexible materials that does not restrict the wearer's joint movement. It uses an integrated gyroscope to detect hip joint angles, thereby determining the assistance stage and magnitude. However, this lower limb exoskeleton can only assist hip flexion, neglecting hip extension and failing to assist in hip extension. Furthermore, most existing lower limb exoskeletons only assist in a single stage of hip flexion or extension.

[0004] In summary, this invention designs a flexible hip joint assistive exoskeleton that can provide assistance to the wearer during both hip flexion and extension phases, and is comfortable to wear without restricting the body's freedom of movement. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the technical problem this invention aims to solve is to provide a flexible hip joint-assisted exoskeleton and its control method.

[0006] The technical solution adopted by the present invention to solve the aforementioned technical problem is as follows:

[0007] This invention provides a flexible hip joint assistive exoskeleton, characterized in that the exoskeleton includes a rear drive unit, a right anterior drive unit, a left anterior drive unit, a left rear Bowden line, a right rear Bowden line, a left knee joint flexible binding structure, a right knee joint flexible binding structure, a flexible bionic vest, a left anterior flexible band, and a right anterior flexible band; wherein, the rear drive unit is located on the rear side of the flexible bionic vest, the left rear Bowden line and the right rear Bowden line are both connected to the rear drive unit, the left rear Bowden line is also connected to the left knee joint flexible binding structure, and the right rear Bowden line... The knee brace is also connected to the flexible binding structure of the right knee joint; the right front drive unit and the left front drive unit are symmetrically installed on the front of the flexible bionic vest, the left front flexible band is connected to the left front drive unit and the flexible binding structure of the left knee joint, and the right front flexible band is connected to the right front drive unit and the flexible binding structure of the right knee joint; the rear drive unit controls the tightening and releasing of the left rear Bowden line and the right rear Bowden line, and the two front drive units control the tightening and releasing of their respective flexible bands. Through the cooperation of the flexible bands and Bowden lines, the hip joint flexion and extension are assisted.

[0008] Furthermore, the left front drive unit includes a left front drive box, a drum motor support, a drive gear, a driven gear, a drum, and a drum motor; the drum motor support is mounted on the bottom plate of the left front drive box, the drum and the drum motor are both mounted on the drum motor support, the drive gear is connected to the drum motor, the driven gear is connected to the shaft at one end of the drum, the driven gear meshes with the drive gear, and the drum is used to wind the left front flexible belt.

[0009] Furthermore, the rear drive unit includes a rear drive box, a motor mounting bracket, a first motor, a second motor, a second reel, and a first reel. The motor mounting bracket is mounted on the bottom plate of the rear drive box, the first motor and the second motor are mounted on the motor mounting bracket, the first reel is connected to the first motor, the second reel is connected to the second motor, the first reel is used to wind the left rear Bowden wire, and the second reel is used to wind the right rear Bowden wire.

[0010] Furthermore, the flexible binding structure for the left knee joint includes two rotatably connected flexible binding members, one of which is worn on the lower part of the human thigh and the other of which is worn on the upper part of the human calf.

[0011] The present invention also provides a control method for the above-mentioned flexible hip joint-assisted exoskeleton, comprising the following:

[0012] The system collects the angles, angular velocities, and angular accelerations of the left and right knee joints during human walking. This data is then standardized and input into a walking state recognizer to identify the human walking state. If the recognition result is flat ground walking, the standardized sample is input into an assist phase recognizer to identify the assist phase. Using the left leg as a reference, if the assist phase recognizer indicates hip flexion, the left anterior flexible band enters the assist phase, and the left posterior Bowden line enters the non-assist phase. If the assist phase recognizer indicates hip extension, the left anterior flexible band enters the non-assist phase, and the left posterior Bowden line enters the assist phase.

[0013] During the left front flexible belt assist phase, the speed deviation is obtained based on the desired speed and actual speed of the drum motor of the left front drive unit. The speed controller converts the speed deviation into a first current through PD control. Simultaneously, a feedforward current is obtained based on the desired equivalent torque at the hip joint and the desired speed of the drum motor of the left front drive unit. The feedforward current is added to the first current to obtain the input current of the drum motor of the left front drive unit, which then controls the drum motor of the left front drive unit to tighten the left front flexible belt. The feedforward current I is expressed as:

[0014]

[0015] Where ζ is the friction correction coefficient, T d R is the expected equivalent torque at the hip joint. i Let be the drum radius of the left front drive unit at time i, Z1 and Z2 be the number of teeth of the driving gear and driven gear of the left front drive unit, respectively, and K be the number of teeth of the driving gear and driven gear of the left front drive unit. M Let L1 be the torque constant of the drum motor of the left front drive unit, L1 be the length of a human thigh, J0 be the rotor inertia of the drum motor of the left front drive unit, and J1 and J2 be the rotational inertia of the driving gear and driven gear of the left front drive unit, respectively. ω is the acceleration of the drum motor of the left front drive unit, B is the viscous friction coefficient of the drum motor of the left front drive unit, and ω is the desired speed of the drum motor of the left front drive unit.

[0016] During the non-assisted phase of the left front flexible belt, the rotor position deviation is obtained from the desired rotor angle and the actual rotor angle of the left front drive unit drum motor. The linear active disturbance rejection controller converts the rotor position deviation into the input current of the left front drive unit drum motor, and then controls the drum motor of the left front drive unit to release the left front flexible belt.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] 1. This invention designs a novel flexible hip joint assistive exoskeleton. It utilizes Bowden wires and flexible straps to connect a flexible bionic vest and a flexible knee joint binding structure. The tightening and releasing of the flexible straps and Bowden wires provide assistance for hip flexion and extension. Only the flexible bionic vest and the flexible knee joint binding structure are worn by the user, and both are made of flexible materials to ensure wearing comfort. Most of the exoskeleton's structure is located in the lower part of the flexible bionic vest, thus concentrating most of the exoskeleton's weight near the wearer's center of gravity, making the wearer more comfortable. The overall structure is lightweight and does not hinder lower limb movement. The total weight is only about 4kg (including the battery), and it can be worn independently.

[0019] 2. To achieve precise assistance for hip flexion and extension, a dual-layer sensing technology is used to control the exoskeleton. In the upper-layer sensing, a data acquisition module collects knee joint data, and the walking state and assistance phase are accurately identified based on the knee joint data, thereby determining the assistance and non-assistance phases of the exoskeleton. This overcomes the high error rate of traditional detection methods based on single features and thresholds. Since the Bowden cable or flexible band has different states in the assistance and non-assistance phases, a dual-modal switching control strategy is used in the lower-layer control to coordinate the tightening and releasing of the Bowden cable or flexible band. Specifically, in the assistance phase, an equivalent torque control strategy is used to tighten the Bowden cable or flexible band to generate tension; in the non-assistance phase, a position control based on linear active disturbance rejection is used to relax the Bowden cable or flexible band. This ensures that the Bowden cable or flexible band does not hinder human movement in the non-assistance phase, thus enabling the exoskeleton to provide effective assistance during both hip flexion and extension phases, reducing the wearer's metabolic rate. The exoskeleton of this invention has a positive effect on elderly people with lower limb muscle weakness who need to walk, improve gait, and prevent falls. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure;

[0021] Figure 2 This is a front view of the overall structure;

[0022] Figure 3 This is an exploded view of the rear drive unit;

[0023] Figure 4 This is a schematic diagram of the control unit.

[0024] Figure 5 This is a schematic diagram of the left front drive unit;

[0025] Figure 6 This is an exploded view of the left front drive unit;

[0026] Figure 7This is a structural diagram of a flexible bionic vest;

[0027] Figure 8 A front view of the flexible bionic vest;

[0028] Figure 9 A schematic diagram of a flexible knee joint binding structure;

[0029] Figure 10 Control flow chart for the support phase;

[0030] Figure 11 This is the control flow chart for the non-assisted phase.

[0031] Reference numerals: 1-Rear drive unit; 2-Right anterior drive unit; 3-Left posterior Bowden line; 4-Right posterior Bowden line; 5-Left knee joint flexible binding structure; 6-Right knee joint flexible binding structure; 7-Data acquisition module; 8-Flexible bionic vest; 9-Left anterior drive unit; 10-Left anterior flexible band; 11-Right anterior flexible band; 12-Control unit;

[0032] 101-Rear drive; 102-Motor mounting bracket; 103-Motor No. 1; 104-Motor No. 2; 105-Spool No. 2; 106-Motor No. 1 drive; 107-Motor No. 2 drive; 108-Spool No. 2; 501-Flexible collar; 502-Lifting lug; 701-Weighing force sensor; 702-IMU inertial sensor; 703-Data acquisition board; 801-Shoulder strap; 802-Waist belt; 803-Inner lining back panel; 901-Left front drive box; 902-Drum motor support; 903-Driving gear; 904-Driven gear; 905-Left front drive unit support frame; 906-Drum; 907-Drum motor; 908-Drum motor drive; 1201-Power management board; 1202-Motor control board; 1203-Processor. Detailed Implementation

[0033] Specific embodiments are given below with reference to the accompanying drawings. These specific embodiments are only used to describe the technical solutions of the present invention in detail, and are not intended to limit the scope of protection of this application.

[0034] This invention provides a flexible hip joint-assisted exoskeleton (hereinafter referred to as exoskeleton, see below) Figures 1-11 The system includes a rear drive unit 1, a right front drive unit 2, a left front drive unit 9, a left rear Bowden line 3, a right rear Bowden line 4, a left knee joint flexible binding structure 5, a right knee joint flexible binding structure 6, a flexible bionic vest 8, a left front flexible band 10, and a right front flexible band 11.

[0035] The flexible bionic vest 8 is worn on the user's upper body. The rear drive unit 1 is installed on the rear side of the flexible bionic vest 8. The upper ends of the left rear Bowden line 3 and the right rear Bowden line 4 are both connected to the rear drive unit 1. The lower end of the left rear Bowden line 3 is connected to the rear side of the left knee joint flexible binding structure 5, and the lower end of the right rear Bowden line 4 is connected to the rear side of the right knee joint flexible binding structure 6. The right front drive unit 2 and the left front drive unit 9 are symmetrically installed on the front side of the flexible bionic vest 8. The upper end of the left front flexible band 10 is connected to the left front drive unit 9, and the lower end of the left front flexible band 10 is connected to the front side of the left knee joint flexible binding structure 5. The upper end of the front flexible band 11 is connected to the right front drive unit 2, and the lower end of the right front flexible band 11 is connected to the front of the right knee joint flexible binding structure 6. The left knee joint flexible binding structure 5 and the right knee joint flexible binding structure 6 are worn on the user's left and right knee joints, respectively. The rear drive unit 1 is used to tighten and release the left rear Bowden line 3 and the right rear Bowden line 4. The left front drive unit 9 is used to tighten and release the left front flexible band 10. The right front drive unit 2 is used to tighten and release the right front flexible band 11. Through the cooperation of the two flexible bands and the two Bowden lines, the flexion and extension of the hip joint are assisted.

[0036] See Figure 3 , 4 The rear drive unit 1 includes a rear drive housing 101, a motor mounting bracket 102, a first motor 103, a second motor 104, a second reel 105, a first motor driver 106, a second motor driver 107, and a first reel 108. The motor mounting bracket 102 is mounted on the base plate of the rear drive housing 101. The first motor 103 and the second motor 104 are embedded in the middle of the motor mounting bracket 102. The first motor 103 is connected to the first reel 108 via a reducer, and the second motor 104 is connected to the second reel 105 via a reducer. The first reel 108 is used to wind the right rear Bowden wire 4, and the second reel 105... Used for winding the left rear side Bowden line 3; the first motor driver 106 is connected to the first motor 103 and the motor control board 1202 of the control unit 12 via wires respectively; the second motor driver 107 is connected to the second motor 104 and the motor control board 1202 of the control unit 12 via wires respectively; the processor 1203 of the control unit 12 sends the identification information to the motor control board 1202 via serial communication; the motor control board 1202 sends PWM signals to the corresponding motor drivers; the motor drivers send signals to the corresponding motors; thereby driving the reel to rotate, realizing the tightening or loosening of the Bowden line; the tightening of the Bowden line assists in hip joint extension.

[0037] The right front drive unit 2 and the left front drive unit 9 are structurally symmetrical. A detailed description will be given using the left front drive unit 9 as an example. (See also...) Figure 5 , 6The left front drive unit 9 includes a left front drive box 901, a drum motor support 902, a drive gear 903, a driven gear 904, a left front drive unit support frame 905, a drum 906, a drum motor 907, and a drum motor driver 908. The left front drive unit support frame 905 is fixedly connected to the lower left part of the front side of the flexible bionic vest 8. The left front drive box 901 is fixed on the left front drive unit support frame 905. Two drum motor support seats 902 are mounted on the base plate of the left front drive box 901. The drum motor 907 is mounted on one of the drum motor support seats 902. The drum motor 907 is connected to the drive gear 903 via a reducer and to the drum motor driver 908 via wires. The motor control board 1202 of the control unit 12 is connected to the 08 and the control unit 12; the rotating shafts at both ends of the drum 906 are rotatably connected to the two drum motor support seats 902. The drum 906 is used to wind the left front flexible belt 10. The driven gear 904 is fixed on the rotating shaft at one end of the drum 906. The driven gear 904 meshes with the driving gear 903; the processor 1203 of the control unit 12 sends an identification signal to the motor control board 1202. The motor control board 1202 sends a PWM signal to the drum motor driver 908. The drum motor driver 908 sends a signal to the drum motor 907 to make the drum motor 907 rotate, thereby driving the drum 906 to rotate, realizing the tightening or releasing of the left front flexible belt 10. Tightening the left front flexible belt 10 assists in hip flexion.

[0038] See Figure 7 , 8 The flexible bionic vest 8 includes shoulder straps 801, a waist belt 802, and an inner back panel 803; one end of each shoulder strap 801 is sewn to the front of the waist belt 802, and the other end is sewn to the upper end of the inner back panel 803; the lower end of the inner back panel 803 is sewn to the rear of the waist belt 802; the outer side of the inner back panel 803 is wrapped with nylon fabric to enhance its stability and improve wearing comfort.

[0039] See Figure 9 The flexible binding structure 5 for the left knee joint and the flexible binding structure 6 for the right knee joint have the same structure. Taking the flexible binding structure 5 for the left knee joint as an example, the flexible binding structure 5 includes flexible binding members. Two flexible binding members 501 are rotatably connected. One flexible binding member is installed on the lower part of the user's thigh, and the other flexible binding member is installed on the upper part of the user's calf. The flexible binding member includes a flexible collar 501. The flexible collar has lugs 502 on both sides. The lugs 502 of the two flexible binding members are rotatably connected to accommodate the bending of the knee joint.

[0040] The exoskeleton also includes a data acquisition module 7; data acquisition modules 7 are installed at both the right knee joint flexible binding structure 6 and the left knee joint flexible binding structure 5. The data acquisition module 7 includes a weighing force sensor, an IMU inertial sensor, and a data acquisition board. Weighing force sensors are installed on the Bowden line and flexible band on the same side of the human body to measure the tension of the Bowden line and flexible band; the IMU inertial sensor is used to measure the knee joint angle, angular velocity, and angular acceleration. The IMU inertial sensor contains a total of 9 channels; the data acquisition board integrates an STM32F103C8T6 chip, a MAX3485 chip, and a TJA1050 CAN transceiver chip. The STM32F103C8T6 chip receives data collected by the weighing force sensor through the MAX3485 chip, receives data collected by the IMU inertial sensor through UART serial communication, and summarizes the collected data and sends it to the processor 1203 through CAN communication.

[0041] The exoskeleton also includes a control unit 12; the control unit 12 is installed in the rear drive box 101 of the rear drive unit 1, and includes a power management board 1201, a motor control board 1202, and a processor 1203; the power management board 1201 acts as a step-down converter, converting the 22.2V voltage of the battery to 5V to power various electrical components. The power management board 1201 uses a PW2815 chip, and the battery model is ACE 1400mAh 6s 22.245c; the processor 1203 receives data collected by the data acquisition module 7 via CAN communication; the core chip of the motor control board 1202 is an STM32F429IGT6, which is used to receive the identification information sent by the processor 1203, and send PWM signals to the first motor driver 106, the second motor driver 107, and the two drum motor drivers, thereby controlling the rotation of the corresponding motors. The motor driver is an ESCON Module 50 / 5; the processor 1203 is a Jetson, which has strong computing power and can deploy deep learning models to achieve perception and decision-making; the first motor 103, the second motor 104, and the drum motor 907 are all ECX TORQUZ 22L brushless BLDC motors with a diameter of 22mm and a maximum power of 48W; each motor is equipped with a motor encoder for collecting position information, model ENX 22EASY INT1-1024 pulses, 3 channels.

[0042] This invention also provides a control method for a flexible hip joint-assisted exoskeleton. This method employs dual-layer sensing technology. In the top-level sensing layer, multi-sensor data fusion is used to identify the hip joint flexion and extension phases. In the bottom-level control layer, a dual-modal switching control strategy is used to assist hip joint flexion and extension. The method includes the following:

[0043] During human walking, the angle, angular velocity and angular acceleration of the knee joint are collected by the IMU inertial sensors of two data acquisition modules 7. Each IMU inertial sensor contains 9 channels. A total of 18 raw data collected by the two IMU inertial sensors are used as a sample and are standardized according to Equation (1).

[0044]

[0045] Where x and x' represent the data before and after standardization, respectively. σ represents the mean, and σ represents the standard deviation.

[0046] The standardized samples are input into the walking state recognizer to identify the human walking state. If the recognition result is walking on flat ground, the standardized samples are input into the assist phase recognizer to identify the assist phase. Taking the left leg as the reference, if the recognition result is the hip flexion stage, the left anterior flexible band enters the assist phase, and the left posterior Bowden line enters the non-assist phase, causing the left anterior flexible band to tighten and the left posterior Bowden line to release, thus assisting hip flexion. If the recognition result is the hip extension stage, the left anterior flexible band enters the non-assist phase, and the left posterior Bowden line enters the assist phase, causing the left posterior Bowden line to tighten and the left anterior flexible band to release, thus assisting hip extension. The same principle applies to hip joint assist when the right leg is the reference.

[0047] The control process for flexible bands and Bowden lines is the same in both the assisted and non-assisted phases. Taking the left anterior flexible band as an example, an equivalent torque control strategy is adopted in the assisted phase, based on the expected equivalent torque T at the hip joint. d and actual equivalent moment T r Obtain the equivalent moment deviation T e The admittance controller will adjust the equivalent torque deviation T. e This is converted to the desired speed ω of the drum motor; on the one hand, the motor feedforward model is based on the desired equivalent torque T. d The desired speed ω of the drum motor is used to obtain the feedforward current; on the other hand, the speed deviation Δω is obtained from the desired speed ω and the actual speed ω1 of the drum motor. The speed controller obtains the first current from the speed deviation Δω through PD control; the feedforward current and the first current are added to obtain the input current of the drum motor, so that the drum motor provides a stable speed, drives the left front flexible belt to tighten, and provides assistance for hip flexion.

[0048] The specific process for calculating the feedforward current is as follows: Assuming the tension of the left anterior flexible band is F, and the angle between the left anterior flexible band and the human thigh is α, then the human-machine interaction force generated by the left anterior flexible band is:

[0049] F1=Fsinα(2)

[0050] The actual equivalent torque T generated at the hip joint by the human-machine interaction force r for:

[0051] T r =F1L1(3)

[0052] Where L1 is the length of the human thigh;

[0053] Equivalent moment deviation T e for:

[0054] T e =T d -T r (4)

[0055] The load torque T of the drum motor is calculated based on the tension of the flexible belt. L for:

[0056]

[0057]

[0058] Among them, R i R i-1 Z1 and Z2 are the radii of the drum at times i and i-1, respectively; Z1 and Z2 are the number of teeth of the driving gear and the driven gear, respectively; ζ is the friction correction coefficient; h is the thickness of the flexible belt; ω1 is the actual speed of the drum motor; and t is time.

[0059] The equation of motion for the drum motor is:

[0060]

[0061] Where T is the electromagnetic torque of the drum motor. Let J be the acceleration of the drum motor, B be the viscous friction coefficient of the drum motor, J = J0 + J1 + J2 be the load-reduced moment of inertia of the drum motor, J0 be the rotor moment of inertia of the drum motor, and J1 and J2 be the moments of inertia of the driving gear and the driven gear, respectively.

[0062] From the expected equivalent moment T d Calculate the expected human-computer interaction force F h for:

[0063]

[0064] Substituting equation (8) into equation (5), we can obtain the load torque T of the drum motor. L for:

[0065]

[0066] The relationship between the electromagnetic torque and winding current of the drum motor is as follows:

[0067] T=K M I(10)

[0068] Where I is the winding current of the drum motor, K M is the torque constant of the drum motor;

[0069] Substituting the desired speed ω of the drum motor into equation (7), and combining equations (7) to (10) in parallel, we obtain the winding current of the drum motor, i.e., the feedforward current I:

[0070]

[0071] In the non-assisted stage, a position control strategy based on linear active disturbance rejection is adopted, which is determined by the desired rotor angle θ of the drum motor. i The rotor position deviation Δθ = θ is obtained by combining the actual rotor angle θ. i -θ; The linear active disturbance rejection controller (L_ADRC) obtains the input current of the drum motor based on the rotor position deviation, realizing unobstructed release of the flexible belt on the left front side. i It depends on the amount of contraction of the left anterior flexible band at the previous moment.

[0072] The walking state recognizer and the assist phase recognizer mentioned above are both trained neural network models. The walking state recognizer can recognize states such as standing, walking, turning counterclockwise, turning clockwise, turning counterclockwise and turning clockwise in a flat environment. There are two assist phase recognizers, one for each leg.

[0073] Any aspects not covered in this invention are applicable to existing technologies.

Claims

1. A flexible hip joint-assisted exoskeleton, characterized in that, The exoskeleton includes a rear drive unit, a right front drive unit, a left front drive unit, a left rear Bowden line, a right rear Bowden line, a left knee joint flexible binding structure, a right knee joint flexible binding structure, a flexible bionic vest, a left front flexible band, and a right front flexible band. The rear drive unit is located at the rear of the flexible bionic vest. The left and right rear Bowden lines are both connected to the rear drive unit. The left rear Bowden line is also connected to the flexible binding structure of the left knee joint, and the right rear Bowden line is also connected to the flexible binding structure of the right knee joint. The right and left front drive units are symmetrically installed at the front of the flexible bionic vest. The left front flexible band is connected to the left front drive unit and the flexible binding structure of the left knee joint, and the right front flexible band is connected to the right front drive unit and the flexible binding structure of the right knee joint. The rear drive unit controls the tightening and releasing of the left and right rear Bowden lines, and the two front drive units control the tightening and releasing of their respective flexible bands. Through the cooperation of the flexible bands and Bowden lines, the hip joint flexion and extension are assisted. The control methods for the aforementioned flexible hip joint-assisted exoskeleton include the following: The system collects the angles, angular velocities, and angular accelerations of the left and right knee joints during human walking. This data is then standardized and input into a walking state recognizer to identify the human walking state. If the recognition result is flat ground walking, the standardized sample is input into an assist phase recognizer to identify the assist phase. Using the left leg as a reference, if the assist phase recognizer indicates hip flexion, the left anterior flexible band enters the assist phase, and the left posterior Bowden line enters the non-assist phase. If the assist phase recognizer indicates hip extension, the left anterior flexible band enters the non-assist phase, and the left posterior Bowden line enters the assist phase. During the left front flexible belt assist phase, the speed deviation is obtained based on the desired and actual speed of the drum motor of the left front drive unit. The speed controller converts the speed deviation into a first current through PD control. Simultaneously, a feedforward current is obtained based on the desired equivalent torque at the hip joint and the desired speed of the drum motor of the left front drive unit. The feedforward current is added to the first current to obtain the input current of the drum motor of the left front drive unit, which then controls the drum motor of the left front drive unit to tighten the left front flexible belt. Represented as: （11） in, This is the friction correction coefficient. The expected equivalent torque at the hip joint. for The drum radius of the left front drive unit at any given time. , These are the number of teeth on the driving gear and driven gear of the left front drive unit, respectively. The torque constant of the drum motor in the left front drive unit is... The length of a human thigh. The moment of inertia of the rotor of the drum motor in the left front drive unit. , These are the moments of inertia of the driving gear and driven gear of the left front drive unit, respectively. The acceleration of the drum motor in the left front drive unit. The coefficient of viscous friction of the drum motor in the left front drive unit. The desired rotational speed of the drum motor in the left front drive unit; During the non-assisted phase of the left front flexible belt, the rotor position deviation is obtained from the desired rotor angle and the actual rotor angle of the left front drive unit drum motor. The linear active disturbance rejection controller converts the rotor position deviation into the input current of the left front drive unit drum motor, and then controls the drum motor of the left front drive unit to release the left front flexible belt.

2. The flexible hip joint-assisted exoskeleton according to claim 1, characterized in that, The left front drive unit includes a left front drive box, a drum motor support, a drive gear, a driven gear, a drum, and a drum motor. The drum motor support is mounted on the bottom plate of the left front drive box. The drum and the drum motor are both mounted on the drum motor support. The drive gear is connected to the drum motor, and the driven gear is connected to the shaft at one end of the drum. The driven gear meshes with the drive gear. The drum is used to wind the left front flexible belt.

3. The flexible hip joint-assisted exoskeleton according to claim 1, characterized in that, The rear drive unit includes a rear drive box, a motor mounting bracket, a first motor, a second motor, a second reel, and a first reel. The motor mounting bracket is mounted on the bottom plate of the rear drive box. The first motor and the second motor are mounted on the motor mounting bracket. The first reel is connected to the first motor, and the second reel is connected to the second motor. The first reel is used to wind the left rear Bowden wire, and the second reel is used to wind the right rear Bowden wire.

4. The flexible hip joint-assisted exoskeleton according to claim 1, characterized in that, The flexible binding structure for the left knee joint includes two rotatably connected flexible binding components, one of which is worn on the lower part of the thigh and the other on the upper part of the calf.

5. The flexible hip joint-assisted exoskeleton according to claim 1, characterized in that, The drum radius of the left front drive unit at any given moment is expressed as: （6） in, for The drum radius of the left front drive unit at any given time. The thickness of the flexible strip on the left front side. This refers to the actual rotational speed of the drum motor in the left front drive unit. For time.

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