Force control method and system for single-leg supporting hydraulic power-assisted exoskeleton and exoskeleton

Abstract

The invention relates to a force control method and system for a single-leg-supported hydraulic power-assisted exoskeleton and the exoskeleton. The force control method for the single-leg-supported hydraulic power-assisted exoskeleton comprises the following steps that 1, the sampling period of the real-time controller is initialized; step 2, acquiring state data of the exoskeleton; 3, the motion states of the left leg foot and the right leg foot are judged respectively, and state data are corrected in real time according to the motion states; and 4, establishing a physical model of the single-leg-supported hydraulic power-assisted exoskeleton. According to the invention, a multi-input multi-output adaptive robust control algorithm is utilized, a cascade force control method is adopted, and an upper layer controller and a lower layer controller are designed. The hydraulic system adopts a parallel pump-valve coordination electro-hydraulic system scheme, a pump control part and a valve control part which operate independently are constructed, the pump control part provides main flow, the valve control part provides micro flow, and the energy efficiency level of the exoskeleton electro-hydraulic system is improved on the premise that precision is not lost.

Description

Technical Field

[0001] The present invention relates to the field of robot control technology, and in particular to a force control method for a single-leg supported hydraulically powered exoskeleton, a high-precision and high-efficiency control system for a single-leg supported hydraulically powered exoskeleton, and a lower limb hydraulically powered exoskeleton. Background Art

[0002] A wearable lower-limb assistive exoskeleton robot is an intelligent, integrated human-machine device that mimics the structure of the human lower limb, enhancing the wearer's physical abilities, including walking endurance, walking speed, and load-bearing capacity. It plays a vital role in disaster relief, construction operations, and improving individual combat capabilities. The exoskeleton-to-human combination can adapt to unstructured environments, possessing exceptional flexibility and the ability to perform complex tasks unmatched by purely mechanical devices. Hydraulic actuators, due to their high power-to-weight ratio and ability to output sufficient force, are ideally suited for compact, heavy-duty systems like lower-limb assistive exoskeletons.

[0003] In a power-assisted exoskeleton system, reducing human-machine forces allows the exoskeleton to accurately track human movement, allowing the wearer to effortlessly carry heavy loads. Therefore, designing a high-precision human-machine force control algorithm is crucial for achieving the exoskeleton's power-assisted functionality. On the other hand, the energy supply system for a lower-limb power-assisted exoskeleton must be portable, and energy sources are very limited. To ensure a long operating time, system energy efficiency is also crucial. Achieving both high-precision and high-efficiency control of a lower-limb hydraulic power-assisted exoskeleton is a key technology for improving exoskeleton performance.

[0004] Achieving high-precision, high-energy-efficiency control of a hydraulic exoskeleton requires addressing two key issues. The first is the design of a high-precision, high-efficiency electro-hydraulic system for the hydraulic exoskeleton. Conventional electro-hydraulic systems for lower-limb hydraulic-assisted exoskeletons often utilize valve-controlled systems. This suffers from throttling and overflow losses, resulting in low energy efficiency. The second challenge is designing a corresponding high-precision, high-energy-efficiency control algorithm for the exoskeleton based on the selected electro-hydraulic system. When walking, a lower-limb exoskeleton can adopt two gaits: single-leg support and double-leg support, depending on the contact between the foot and the ground. In the single-leg support mode, one leg supports while the other swings. The coupling between the joints of the swinging and supporting legs complicates controller design. Furthermore, existing control methods for hydraulic-assisted exoskeletons focus on addressing the inherent high-order nonlinearities and modeling uncertainties inherent in hydraulic exoskeleton systems. These methods only achieve high-precision force control without considering energy consumption, resulting in high system energy consumption. Summary of the Invention

[0005] Based on this, it is necessary to provide a force control method, system and exoskeleton for a single-leg supporting hydraulically assisted exoskeleton to address the problem that the joints of the swinging leg and the supporting leg of the lower limb exoskeleton are coupled with each other in the single-leg supporting state, and the existing controller design is difficult to accurately control and consumes a lot of energy.

[0006] In a first aspect, the present invention provides a force control method for a single-leg support hydraulically assisted exoskeleton, which is used to control the hydraulically assisted exoskeleton in a single-leg support state. The hydraulically assisted exoskeleton includes: a left leg and a right leg with identical structures, each of which is provided with three hydraulic cylinders for controlling the rotation of the corresponding ankle joint, knee joint, and hip joint. The method includes the following steps:

[0007] Step 1: Obtain the state data of the exoskeleton in the single-leg support state, and judge the movement state of the left leg and the right leg respectively, so as to judge the swing leg and the supporting leg of the exoskeleton, and correct the state data in real time according to the movement state.

[0008] Step 2: Establish a physical model of the exoskeleton in the single-leg support state, and construct the upper-layer controller and the lower-layer controller based on the physical model.

[0009] Step 3: Based on the upper and lower controllers, the control voltages of the variable speed pumps and servo valves used to drive the hydraulic cylinders of the joints in the exoskeleton in the single-leg support state are obtained.

[0010] Step 4: Generate a corresponding current signal based on the control voltage to control the corresponding variable speed pump and servo valve, thereby controlling the pressure at both ends of the hydraulic cylinder, realizing the movement of the hydraulic cylinder and driving the rotation of each joint in the single-leg support state of the exoskeleton.

[0011] In a second aspect, the present invention also proposes a high-precision, high-energy-efficiency control system for a single-leg support hydraulically assisted exoskeleton, which utilizes the force control method for the single-leg support hydraulically assisted exoskeleton described in the first aspect. The high-precision, high-energy-efficiency control system for a single-leg support hydraulically assisted exoskeleton includes a data acquisition module, a model building module, a signal generation module, and a tracking control module.

[0012] Among them, the data acquisition module is used to obtain the state data of the exoskeleton in the single-leg support state, and to determine the movement state of the left and right leg feet respectively, thereby determining the swing leg and support leg of the exoskeleton, and to correct the state data in real time according to the movement state. The model establishment module is used to establish a physical model of the exoskeleton in the single-leg support state, and to construct an upper-level controller and a lower-level controller based on the physical model. The signal generation module is used to obtain the control voltage of the variable speed pump and servo valve used to drive the hydraulic cylinder of each joint in the exoskeleton in the single-leg support state based on the upper-level controller and the lower-level controller, and then generate the corresponding current signal. The tracking control module is used to control the corresponding variable speed pump and servo valve based on the current signal, and then control the pressure at both ends of the hydraulic cylinder, realize the movement of the hydraulic cylinder and drive the rotation of each joint in the exoskeleton in the single-leg support state.

[0013] In a third aspect, the present invention further provides a lower limb hydraulically assisted exoskeleton, which is controlled using the force control method of the single-leg support hydraulically assisted exoskeleton described in the first aspect. The lower limb hydraulically assisted exoskeleton includes: a backboard, a left bottom plate, a right bottom plate, a left thigh rod, a right thigh rod, a left calf rod, a right calf rod, a left footboard, a right footboard, a left hip joint hydraulic cylinder, a right hip joint hydraulic cylinder, a left knee joint hydraulic cylinder, a right knee joint hydraulic cylinder, a left ankle joint hydraulic cylinder, a right ankle joint hydraulic cylinder, multiple variable speed pumps, a switch valve and a servo valve, multiple sensors, and a real-time controller.

[0014] Among them, the left bottom plate and the right bottom plate are both connected to the bottom of the back plate; the left thigh rod and the right thigh rod are rotatably connected to the bottom of the left bottom plate and the right bottom plate respectively; the left calf rod and the right calf rod are rotatably connected to the end of the left thigh rod and the right thigh rod away from the back plate respectively; the left foot plate and the right foot plate are rotatably connected to the end of the left calf rod and the right calf rod away from the back plate respectively; the left leg hip joint hydraulic cylinder and the right leg hip joint hydraulic cylinder are respectively used to drive the back plate and the left thigh rod to rotate relative to each other, and the back plate and the right thigh rod to rotate relative to each other; the left leg knee joint hydraulic cylinder and the right leg knee joint hydraulic cylinder are respectively used to drive the left thigh rod and the left calf rod to rotate relative to each other The left leg ankle joint hydraulic cylinder and the right leg ankle joint hydraulic cylinder are used to drive the left calf rod and the left footboard to rotate relative to each other, and the right calf rod and the right footboard to rotate relative to each other; multiple variable speed pumps, switch valves and servo valves are used to drive the right leg ankle joint hydraulic cylinder, the right leg knee joint hydraulic cylinder, the right leg hip joint hydraulic cylinder, the left leg ankle joint hydraulic cylinder, the left leg knee joint hydraulic cylinder and the left leg hip joint hydraulic cylinder to move; multiple sensors are used to collect status data of the exoskeleton; the real-time controller is used to output the hydraulic cylinder control quantity according to the status data, and control the operating status of each hydraulic cylinder according to the hydraulic cylinder control quantity.

[0015] The beneficial effects of the present invention are:

[0016] 1. The present invention utilizes a multi-input multi-output adaptive robust control algorithm and adopts a cascade force control method to design upper and lower layer controllers. The hydraulic system adopts a parallel pump-valve coordinated electro-hydraulic system solution to construct an independently operated pump control part and valve control part, so that the pump control part provides the main flow and the valve control part provides a small flow. Under the premise of not losing accuracy, the energy efficiency level of the exoskeleton electro-hydraulic system is improved. In the lower layer controller, the rodless cavity of the hydraulic cylinder adopts position tracking control, and the rod cavity of the hydraulic cylinder adopts pressure tracking control, so that the pressure of one cavity of the hydraulic cylinder is always in the minimum pressure state. This solves the technical problem of high energy consumption of the existing lower limb exoskeleton control method when the exoskeleton is in a single-leg support state. It not only realizes the good following and assistance of the hydraulically assisted exoskeleton supporting leg and the swinging leg to the human movement during single-leg support, improves the control accuracy, but also reduces the energy consumption of the system, achieves a longer endurance time, and has a strong application value.

[0017] 2. The lower limb hydraulic power-assisted exoskeleton of the present invention has the advantages of small size, light weight, flexible layout, and compact structure. It also has the characteristics of being able to output large force or torque, sensitive movement response, and easy control.

[0018] 3. The sensor system of the present invention mainly comprises a back force sensor and rotary encoders for each joint to achieve more effective and reliable human-computer interaction.

[0019] 4. The present invention fully considers the wearer's control over the exoskeleton, reduces the use of hydraulic cylinder flow and energy consumption, is effective and reliable in human-machine interaction, and has the characteristics of rapid response to human movement intentions.

[0020] 5. This invention incorporates the exoskeleton wearer as a participant in system control. Within the walking plane, the wearer ensures forward and backward balance of the entire system, preventing the exoskeleton from falling. Furthermore, the control method of this invention utilizes a cascade control strategy, designing upper and lower-level controllers to achieve trajectory planning and tracking for the lower-limb assist exoskeleton. This control method is simple to implement, easy to implement in engineering, and offers flexible control. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 This is a schematic diagram of the three-dimensional structure of the hydraulically assisted exoskeleton;

[0023] Figure 2Coordinate the schematic diagram of the electro-hydraulic system for parallel pumps and valves;

[0024] Figure 3 A control flow chart of the force control method for a single-leg support hydraulically assisted exoskeleton;

[0025] Figure 4 A step-by-step diagram of the force control method for a single-leg support hydraulically assisted exoskeleton.

[0026] In the figure: right footboard 1, right ankle joint hydraulic cylinder 2, right adjusting rod 3, right calf rod 4, right thigh rod 5, right hip joint hydraulic cylinder 6, right four-bar mechanism 7, right base plate 8, left footboard 9, left adjusting rod 10, left ankle joint hydraulic cylinder 11, left calf rod 12, left knee joint hydraulic cylinder 13, right knee joint hydraulic cylinder 14, left thigh rod 15, left hip joint hydraulic cylinder 16, left four-bar mechanism 17, left base plate 18, back plate 19, switch valve 20, electro-hydraulic servo valve 21, back strap 22. DETAILED DESCRIPTION

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0028] It should be noted that when a component is referred to as being "mounted on" another component, it may be directly on the other component or there may be a central component. When a component is considered to be "set on" another component, it may be directly set on the other component or there may be a central component. When a component is considered to be "fixed to" another component, it may be directly fixed to the other component or there may be a central component.

[0029] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used herein in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "or / and" as used herein includes any and all combinations of one or more of the associated listed items.

[0031] This embodiment provides a lower limb hydraulic power-assisted exoskeleton. Figure 1 The lower limb hydraulic power-assisted exoskeleton includes: a right footplate 1, a right ankle joint hydraulic cylinder 2, a right adjustment rod 3, a right calf rod 4, a right thigh rod 5, a right hip joint hydraulic cylinder 6, a right four-bar mechanism 7, a right bottom plate 8, a left footplate 9, a left adjustment rod 10, a left ankle joint hydraulic cylinder 11, a left calf rod 12, a left knee joint hydraulic cylinder 13, a right knee joint hydraulic cylinder 14, a left thigh rod 15, a left hip joint hydraulic cylinder 16, a left four-bar mechanism 17, a left bottom plate 18, a back plate 19, a variable speed pump, a switch valve 20, an electro-hydraulic servo valve 21, multiple sensors and a real-time controller.

[0032] The back plate 19 is fixedly connected to a back strap 22, and the left and right thigh rods 5 are each fixedly connected to a leg strap ( Figure 1Not shown). The left and right base plates 8 are fixedly connected to the lower end of the back plate 19. The right base plate 8 is rotatably connected to the top end of the right thigh rod, and the right leg hip joint hydraulic cylinder 6 is connected between the right base plate 8 and the driving rod of the four-bar mechanism, which is used to drive the back plate 19 and the right thigh rod 5 to rotate relative to each other. The lower end of the right thigh rod 5 is rotatably connected to the upper end of the right calf rod 4, and the right leg knee joint hydraulic cylinder 14 is connected between the right thigh rod 5 and the right calf rod 4, which is used to rotate relative to each other. The right calf rod 4 is movably connected to the right calf adjustment rod for adjusting the length of the calf. The lower end of the right calf adjustment rod is rotatably connected to the upper end of the right foot plate 1, and the right leg ankle joint hydraulic cylinder 2 is connected between the right calf rod 4 and the right foot plate 1, which is used to rotate relative to each other. Correspondingly, the connections of the rods of the left leg are analogous to those of the right leg. The upper rear end of the back panel 19 houses the servo valves for the right leg joints and the on / off valve 20 for the variable speed pump (not shown). The lower rear end of the back panel 19 houses the servo valves for the left leg joints and the on / off valve 20 for the variable speed pump. The exoskeleton is worn by tying the back straps 22 to the back and the thigh straps to the thighs. Both the back straps 22 and the thigh straps are elastic, allowing the wearer to quickly remove the exoskeleton in the event of a malfunction, thus preventing damage to the wearer in an emergency. The connection between the right footplate 1 and the right calf adjustment rod is defined as the right ankle joint, the connection between the left footplate 9 and the left calf adjustment rod is defined as the left ankle joint, the connection between the right calf rod 4 and the right thigh rod 5 is defined as the right knee joint, the connection between the left calf rod 12 and the left thigh rod 15 is defined as the left knee joint, the connection between the right thigh rod 5 and the right base plate 8 is defined as the right hip joint, and the connection between the left thigh rod 15 and the left base plate 18 is defined as the left hip joint. The right footplate 1, right adjustment rod 3, right calf rod 4, right thigh rod 5, right four-bar linkage 7, and right base plate 8 collectively constitute the right leg and foot, while the left footplate 9, left adjustment rod 10, left calf rod 12, left thigh rod 15, left four-bar linkage 17, and left base plate 18 collectively constitute the left leg and foot. The connection between the back plate 19 and the wearer is defined as the back of the exoskeleton.

[0033] The variable speed pump, on-off valve 20, and electro-hydraulic servo valve 21 are respectively connected to the right ankle joint hydraulic cylinder 2, right knee joint hydraulic cylinder 14, right hip joint hydraulic cylinder 6, left ankle joint hydraulic cylinder 11, left knee joint hydraulic cylinder 13, and left hip joint hydraulic cylinder 16, controlling the operating status of the right ankle joint hydraulic cylinder 2, right knee joint hydraulic cylinder 14, right hip joint hydraulic cylinder 6, left ankle joint hydraulic cylinder 11, left knee joint hydraulic cylinder 13, and left hip joint hydraulic cylinder 16. Multiple sensors are installed at different locations on the exoskeleton to collect status data of the hydraulically assisted exoskeleton. These sensors include back force sensors, foot force sensors, exoskeleton actual angle sensors, ankle joint hydraulic cylinder actual pressure sensors, knee joint hydraulic cylinder actual pressure sensors, hip joint hydraulic cylinder actual pressure sensors, and foot support force sensors. The back force sensor is installed on the backboard 19 to detect back force. The foot force sensor is installed on the footboard to detect foot force. The exoskeleton's actual angle sensors are installed at each joint of the exoskeleton to obtain the actual angles of each joint. Ankle joint hydraulic cylinder actual pressure sensors are installed at the left and right ankle joints to obtain the actual pressures of the right ankle joint hydraulic cylinder 2 and the left ankle joint hydraulic cylinder 11. Knee joint hydraulic cylinder actual pressure sensors are installed at the left and right knee joints to obtain the actual pressures of the right knee joint hydraulic cylinder 14 and the left knee joint hydraulic cylinder 13. Hip joint hydraulic cylinder actual pressure sensors are installed at the right and left hip joints to obtain the actual pressures of the right hip joint hydraulic cylinder 6 and the left hip joint hydraulic cylinder 16. Foot support force sensors are installed on the right footboard 1 and the left footboard 9 to obtain the right foot support force and the left foot support force. The real-time controller is used to output the hydraulic cylinder control value based on the status data and control the operating status of each hydraulic cylinder based on the hydraulic cylinder control value. The controller includes an upper-level controller and a lower-level controller. The upper-level controller is used to output the predicted trajectory of human motion, and the lower-level controller is used to output control signals for the variable speed pump and servo valve, and to control the operating state of the hydraulic cylinder according to the control signals to achieve energy-saving and precise tracking of the exoskeleton.

[0034] In this embodiment, the present invention changes the original power system of the ankle joint, knee joint and hip joint, and improves the original power system of each joint into a parallel pump valve coordinated electro-hydraulic system. Figure 2Each parallel pump-valve coordinated electro-hydraulic system includes a parallel coordinated pump control section and a valve control section. The pump control section includes a variable speed pump PS1i and two two-way on-off valves 20SV1i and SV2i that determine the flow direction of the variable speed pump PS1i's outlet. The valve control section includes four two-way electro-hydraulic servo valves 21PV1i, PV2i, PV3i, and PV4i and a hydraulic oil source PS2. The electro-hydraulic servo valves 21PV1i and PV2i control the flow of hydraulic oil from the hydraulic source PS2 to the two chambers of the corresponding hydraulic cylinder, while the electro-hydraulic servo valves 21PV3i and PV4i control the flow of hydraulic oil from the two chambers of the corresponding hydraulic cylinder to the oil tank.

[0035] Of course, the present invention not only improves the power systems of the ankle, knee, and hip joints, but also requires the coordinated movement of the six joints in conjunction with the required single-leg support hydraulic-assisted exoskeleton control method. The single-leg support hydraulic-assisted exoskeleton force control method of the present invention utilizes an adaptive robust control algorithm (ARC) that effectively overcomes the effects of model uncertainty. Its principle is to continuously adjust the system model parameters by designing an adaptive law, perform feedforward compensation on the control model to ensure zero tracking error under static conditions, and design robust feedback to ensure the dynamic characteristics and stability of the single-leg support hydraulic-assisted exoskeleton system. Simultaneously, utilizing a cascaded force control method, an upper-level controller is designed to obtain reference trajectories for the joints of the exoskeleton's support and swing legs. The lower-level rodless cavity position tracking controller, the lower-level rod cavity pressure planner, and the lower-level rod cavity pressure tracking controller implement tracking of the joint reference trajectories and reduce system energy consumption. Furthermore, the flow distribution scheme uses a pump to provide low-frequency flow and a valve to provide high-frequency flow, reducing system energy consumption during single-leg support. The control algorithm is simple to implement, easy to implement in engineering, and flexible to control.

[0036] Based on the above lower limb hydraulic power-assisted exoskeleton, the force control method in the single-leg support state is described in detail below. Figure 3 and Figure 4 The single-leg support hydraulic power-assisted exoskeleton force control method includes the following steps:

[0037] S1: Initialize the real-time controller's sampling period. Rotate the left and right feet to a horizontal position. Rotate the right calf bar 4, right thigh bar 5, left calf bar 12, left thigh bar 15, and backboard 19 to a vertical position. Initialize multiple sensors and zero each sensor value. In this embodiment, the sampling period is set between 10 and 20 ms.

[0038] S2: Determine the motion state of the left and right legs, respectively. The motion state determination method includes: determining whether the left and right legs are exerting pressure on the ground. If so, the left leg, right leg, or both legs are used as the supporting leg; otherwise, the left leg or right leg is used as the swinging leg. During human motion, the left or right leg may be in a supporting state or a swinging state, that is, the left or right leg may be used as a supporting leg or a swinging leg at a given moment. By installing foot pressure sensors on the soles of the human feet or under the exoskeleton footplates, the pressure signals of the human legs are obtained in real time, thereby determining the motion state of the right and left legs of the exoskeleton.

[0039] S3: Build a physical model for the single-leg support hydraulically assisted exoskeleton and convert it into a state equation based on the state data. The physical model includes: a human-machine interface model for the contact points between the user and the exoskeleton back and the swinging leg foot; a kinematic model for the exoskeleton during single-leg support; and a dynamic model for the hydraulic actuator.

[0040] The human-machine interface model between the human and the exoskeleton back and the swinging leg can be expressed as:

[0041]

[0042] Among them, F hm =[F hmub ,F hmf2p ] T is the human-machine force, F hmub =[F hmubx ,F hmuby ,τ hmubz ] T F is the human-machine force at the contact point between the human and the exoskeleton robot’s back, hmubx 、F hmuby , τ hmubz They represent the forces generated by the contact points between the human and the exoskeleton robot in the x, y, and z directions, respectively. hmf2p =[F hmfx ,F hmfy ,τ hmfz ] T is the human-machine force at the contact point between the human and the right foot of the exoskeleton robot, F hmfx ,F hmfy ,τ hmfz They represent the forces generated by the contact point between the human and the right foot of the exoskeleton robot in the x, y, and z directions, respectively, and dτ is F hm Differentiation of the integral variable, K = diag{K ubx ,K uby ,K ubz ,K f2px ,K f2py ,Kf2pz} is the stiffness of the human-machine interface, K ubx ,K uby ,K ubz They represent the human-machine interface stiffness of the contact point between the human and the exoskeleton robot in the x, y, and z directions, respectively, and K f2px ,K f2py ,K f2pz They represent the human-machine interface stiffness of the contact point between the human and the right foot of the exoskeleton robot in the x, y, and z directions, respectively. h =[x hubx ,x huby ,x hubz ,x hf2px ,x hf2py ,x hf2pz ] T is the Cartesian coordinate position of the person at the point of contact between the back and the right foot, x hubx ,x huby ,x hubz Indicates the Cartesian coordinate position of the person at the back contact point in the x, y, and z directions, x hf2px ,x hf2py ,x hf2pz Indicates the Cartesian coordinate position of the person at the right foot contact point in the x, y, and z directions, x e =[x eubx ,x euby ,x eubz ,x ef2px ,x ef2py ,x ef2pz ] T is the Cartesian coordinate position of the exoskeleton at the contact point between the back and the right foot, x eubx ,x euby ,x eubz Indicates the Cartesian coordinate position of the exoskeleton in the x, y, and z directions at the back contact point. ef2px ,x ef2py ,x ef2pz Indicates the Cartesian coordinate position of the exoskeleton in the x, y, and z directions at the right foot contact point. For concentrated interference and modeling uncertainty about the human-machine interface, Indicates the concentrated interference and modeling uncertainty in the x, y, and z directions at the contact point between the human and the exoskeleton back. Represents the concentrated interference and modeling uncertainty in the x, y, and z directions at the contact point between the human and the exoskeleton's right foot.

[0043] Through the integration of human-machine forces Replace F hm , the state equation of the human-machine interface model is obtained as:

[0044]

[0045] In this embodiment, the motion model of the exoskeleton when supporting one leg is:

[0046]

[0047] τ act =[τ1τ2τ3τ4τ5τ6] T ,

[0048] Where M Lsp is the inertia matrix, C Lsp is the centrifugal force and Coriolis force matrix, G Lsp is the gravity matrix, B is the damping matrix, is the centralized modeling error, τ act is the driving torque of the exoskeleton joint, τ1~τ6 are the driving torques of the six exoskeleton joints, τ i represents the driving torque of the i-th exoskeleton joint, F hmub is the human-machine force at the back contact point, F hmf2p is the human-machine force at the back contact point, J ub and J f2p is the Jacobian matrix of the back and right foot joints with the exoskeleton, q = [q1 q2 q3 q4q5 q6] T is the exoskeleton joint angle, q1~q6 are the angles of the six exoskeleton joints respectively, represents the angular velocity of the exoskeleton joints, represents the angular acceleration of the exoskeleton joint, x Li is the displacement of hydraulic cylinder i, is x Li About q i The first-order partial derivative of , q i represents the joint angle of the i-th joint, P 1i and P 2i Indicates the actual pressure of the rodless chamber and the rod chamber in the hydraulic cylinder i, A 1i and A 2i V represents the effective area of the rodless cavity and the rod cavity in the hydraulic cylinder i. 1i =V h1i +A 1i x Li and V 2i =V h2i -A 2i x Li are the chamber volumes of the rodless chamber and the rod chamber in the hydraulic cylinder i, V h1i ,V h2i It is q i =0, the volume of the two chambers of hydraulic cylinder i.

[0049] The dynamic model of the hydraulic actuator can be expressed as:

[0050]

[0051] Q 1i =Q 1vi +Q 1pi , Q 2i =Q 2vi -Q 2pi

[0052] Q 1vi =Q pv1i -Q pv3i , Q 2vi =-Q pv2i +Q pv4i

[0053] x pvji =u pvji ,j=1,2,3,4

[0054] ΔP pv1i =P s -P 1i , ΔP pv2i =P s -P 2i , ΔP pv3i =P 1i -P r , ΔP pv4i =P 2i -P r

[0055] Q 1pi =sw 1i Q pi , Q 2pi =sw 2i Q pi

[0056]

[0057] Q pi =k pi u pi ,i=1,2,…6

[0058] Where, β e Represents the bulk elastic modulus. Q 1i , Q 2i are the oil inlet flow rate of the rodless chamber and the oil outlet flow rate of the rod chamber in the hydraulic cylinder i, and represents the concentrated modeling error and uncertain disturbance in the hydraulic actuator dynamics model, Q 1vi and Q 2viThey represent the oil flow rate from the rodless chamber to the valve control part and the oil flow rate from the rod chamber in the hydraulic cylinder i, respectively. 1pi and Q 2pi They represent the oil flow rate of the rodless chamber and the rod chamber from the pump control part in the hydraulic cylinder i, respectively, and Q pvji represents the flow rate of the jth servo valve corresponding to the hydraulic cylinder i, k qpvji is the flow gain coefficient of the jth servo valve corresponding to the hydraulic cylinder i, x pvji is the valve core displacement of the jth servo valve corresponding to hydraulic cylinder i, P s With P r They are the oil supply pressure of the valve control part and the pressure of the oil tank, ΔP pv1i and ΔP pv2i Respectively represent the oil supply pressure P of the valve control part in the hydraulic cylinder i s The actual pressure of the rodless chamber P 1i And the actual pressure of the rod chamber P 2i Pressure difference, ΔP pv3i and ΔP pv4i They represent the actual pressure P in the rodless chamber of hydraulic cylinder i. 1i And the actual pressure of the rod chamber P 2i With the tank pressure P r The pressure difference, u pvji is the control voltage of the jth servo valve corresponding to hydraulic cylinder i, Q pi represents the output flow of the variable speed pump corresponding to the hydraulic cylinder i, k pi and u pi They represent the flow gain coefficient and control voltage of the variable speed pump corresponding to the hydraulic cylinder i respectively.

[0059] The method of converting the physical model into the equation of state includes the following steps:

[0060] x2=q,

[0061] x4=P1=[P 11 P 12 P 13 P 14 P 15 P 16 ] T

[0062] x5=P2=[P 21 P 22 P 23 P 24 P 25 P 26 ] T

[0063] x=[x1T x2 T x3 T x4 T x5 T ] T

[0064] Where x1~x5 represent the state variables defined when the state is converted; P1 and P2 represent the actual pressures of the rodless cavity and rod cavity of the six joint hydraulic cylinders of the exoskeleton, respectively.

[0065] Define the concentrated model uncertainty as:

[0066]

[0067] The centralized model uncertainty is divided into two parts: constant and time-varying function, and we get represents the centralized model uncertainty defined for each model during modeling, Δ i'n and Δ i' Respectively represent The constant part and the time-varying part.

[0068] set up θ q =[β T B θ T Δ 2n T β e Δ 3n T ] T ,θ p2i =[β e Δ 4ni ] T , where K f' =[1 / K ubx 1 / K uby 1 / K ubz 1 / K f2px 1 / K f2py 1 / K f2pz ] T , Δ 1n =[Δ 1ubnx Δ 1ubny Δ 1ubnz Δ 1f2pnx Δ 1f2pny Δ 1f2pnz ] T , β is the system parameter of the double-leg support hydraulic power-assisted exoskeleton, B θ =[B1 B2 B3 B4 B5 B6] T is the system damping of the exoskeleton, Δ 2n =[Δ2n1 Δ 2n2 Δ 2n3 Δ 2n4 Δ 2n5 Δ 2n6 ] T , Δ 3n =[Δ 3n1 Δ 3n2 Δ 3n3 Δ 3n4 Δ 3n5 Δ 3n6 ] T , Δ 4n =[Δ 4n1 Δ 4n2 Δ 4n3 Δ 4n4 Δ 4n5 Δ 4n6 ] T .

[0069] The state equation of the physical model of the single-leg support hydraulic power-assisted exoskeleton is:

[0070]

[0071] Where, h represents the force arm between the hydraulic cylinder of each joint and the joint, A1=diag{A 11 ,A 12 ,A 13 ,A 14 ,A 15 ,A 16}, A2=diag{A 21 ,A 22 ,A 23 ,A 24 ,A 25 ,A 26}, A1 represents the piston area of the rodless cavity of the hydraulic cylinder of each joint of the exoskeleton, A2 represents the piston area of the rod cavity of the hydraulic cylinder of each joint of the exoskeleton, F L =A1P1-A2P2,Q v =N1Q1+N2Q2, Q v =[Q 11 A 11 / V 11 +Q 21 A 21 / V 21 ,Q 12 A 12 / V 12 +Q 22 A 22 / V 22 ,Q 13 A 13 / V 13+Q 23 A 23 / V 23 ,Q 14 A 14 / V 14 +Q 24 A 24 / V 24 ,Q 15 A 15 / V 15 +Q 25 A 25 / V<0OO0277>,Q 16 A 16 / V 16 +Q 26 A 26 / V 26 T ,Q1 = [Q 11 ,Q 12 ,Q 13 ,Q 14 ,Q 15 ,Q 16 T ,Q2 = [Q 21 ,Q 22 ,Q 23 ,Q 24 ,Q 25 ,Q 26 T ,N1 = diag{A 11 / V 11 ,A 12 / V 12 ,A[[ID=8I]] 13 / V 13 ,A 14 / V 14 ,A 15 / V 15 ,A 16 / V 16},N2 = diag{A 21 / V 21 ,A 22 / V 22 [[ID=IO4]],A 23 / V 23 ,A<OO00317> / V 24 ,A 25 / V 25 ,A 26 / V 26}, Q v 、q v 、N1、N2 all represent user - defined variables.​​​

[0072] S4: Obtain the back force and swing leg foot force at the contact points between the exoskeleton back and the swing leg foot. Using these back force and swing leg foot forces as input, the upper-level controller obtains the reference trajectories of the exoskeleton's supporting and swing legs.

[0073] The control method of the upper controller includes the following steps:

[0074] According to the state equation, the first tracking error z1 is z1=x1-x 1d , where x 1d is the integration of the desired human-machine force on the back and right foot in the x, y, and z directions, which is zero; e As a virtual control input, x e Design control law x m This makes the first tracking error z1 of the human-machine force quickly approach zero.

[0075] Let x m =x ma +x ms +x msn , where x m represents the desired exoskeleton end position at the contact point between the human and the exoskeleton, x ma represents the model compensation term, x ms =K1z1, and By x ma After parameter linearization, x ms represents the linear robust feedback term, x msn Denotes the nonlinear robust feedback term, K1=diag{K 11 ,K 12 ,K 13 ,K 14 ,K 15 ,K 16} is the linear feedback gain, is θ F The estimated value is taken as And the estimated values range from: in is the parameter θ F Estimated value of In this embodiment, the minimum value of is the parameter θ F Estimated value of In this embodiment, the maximum value of In this embodiment, the estimated value In the upper controller, the adaptive law It is found that Γ1 is a positive definite gain matrix. In this embodiment, Γ1=diag{0,0,0,0,0,0,2,2,2,2,2,2} is taken. The mapping function is:

[0076]

[0077] Where, i is the independent variable, θ Fmaxi ,θ Fmini are θ F The maximum and minimum values of the i-th element. msn satisfy:

[0078]

[0079] in, is an estimate Subtract the actual value θ F , ε1 is a threshold value and is any non-negative number. In this example, ε1 = 1, x msn =[000000] T .

[0080] According to the design of x m , and the inverse kinematics model of the single-leg support hydraulic assisted exoskeleton to obtain the desired angle q of the exoskeleton joint m =[q m1 q m2 q m3 q m4 q m5 q m6 ] T :

[0081] q m =invkine(x m )

[0082] Where invkine stands for inverse kinematics. m is the desired joint angle obtained by the exoskeleton. When q = q m When , the human-machine interaction force can be zero or bounded, so q m is considered as the human’s movement intention. According to the expected angle q of the exoskeleton joint mi , i = 1, 2, ..., 6, and smoothed by a fourth-order filter to obtain the reference angle, reference angular velocity, reference angular acceleration and reference angular jerk of each joint of the exoskeleton; wherein the state equation of the fourth-order filter is as follows:

[0083]

[0084] i=1,2,…,6

[0085] Where, Represent the filtered reference angle, reference angular velocity, reference angular acceleration and reference angular jerk respectively, from q mi to η 1i The transfer function is:

[0086]

[0087] Through the above transfer function, we can obtain q mi Converted into the required smooth reference rotation angle η of each joint of the exoskeleton 1i ; Wherein, a1, a2, a3 and a4 are coefficients in the transfer function, which are obtained by pole configuration. In this embodiment, the closed-loop pole is set to 20 radians per second, and the values of a1, a2, a3 and a4 are a1 = 80, a2 = 2400, a3 = 32000, and a4 = 160000 respectively. In practice, it is not limited to this. The reference angle of the joint in the single-leg support state can be obtained Reference angular velocity and the reference angular acceleration

[0088] S5: Obtain the actual angle values of each joint of the exoskeleton's supporting and swinging legs. Using the actual angles and reference angles as input, the lower-level rodless cavity position tracking controller obtains the desired driving force and rodless cavity flow rate of each hydraulic cylinder in the exoskeleton's supporting and swinging legs. The control method of the lower-level rodless cavity position tracking controller includes the following steps:

[0089] Assume the second tracking error in Represent the reference angles of the six joints of the exoskeleton. Define a transformation equation:

[0090]

[0091] K2 is any non-negative number. In this embodiment, K2=diag{40,40,40,40,40}. is the first-order derivative of z2, q r Represents the intermediate variables defined to generate the desired angular velocity and angular acceleration for each joint. q r The first derivative of , z3 is the third tracking error. K 2i Represents the i-th element of K2. Represents the estimated reference angular velocity of the joint in the single-leg support state.

[0092] Let Bx3 = YB B θ , Where β is the model parameter of the mechanical structure, B θ =[B1 B2 B3 B4 B5 B6] T Y is the matrix of joint damping coefficients. B1, B2, B3, B4, B5, and B6 represent the damping coefficients of the ankle joint of the supporting leg, the knee joint of the supporting leg, the hip joint of the supporting leg, the hip joint of the swinging leg, the knee joint of the swinging leg, and the ankle joint of the swinging leg, respectively. B The diagonal matrix represents the actual angular velocity of each joint, and f0 and Y represent the terms obtained by linearizing the parameters on the left side of the equal sign in the formula.

[0093] (5.1) F L As a virtual control input, F L Design control law F Ld This makes the second tracking error z2 approach zero quickly.

[0094] Let F Ld =F Lda +F Lds +F Ldsn ,in, It represents the model compensation term. Lds =-h -1 K3z3, which represents the linear robust feedback term. F Ldsn K3 is the linear feedback gain, and in this embodiment, its value is K3=diag{130,130,130,130,40}. They are β, B θ , Δ 2n An estimated value of θ q =[β T B θ T Δ 2n T β e Δ 3n T ] T , which represents the defined concentrated parameter. In this embodiment, θ q The initial value is is the centralized parameter θ q Estimated value of The minimum value of . In this embodiment, the values are: For the parameter θ q Estimated value of The maximum value of . In this embodiment, the values are: θ qmaxi ,θ qmini are θ q The maximum and minimum values of the i-th element, estimated value In the lower layer rodless cavity position tracking controller, the adaptive law τ4 is obtained by step (5.3), Γ2 is a positive definite gain matrix. In this embodiment, it is selected as Γ2=diag{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, The mapping function is:

[0095]

[0096] Where, i is the independent variable, for The i-th parameter of . Let φ3=[-Y -Y B I 6×6 0 6×1 0 6×6 ] T . F Ldsn satisfy:

[0097]

[0098] Where, is an estimate Subtract the actual value θ q , ε2 is a threshold value and is any non-negative number; in this example, ε2 = 1, F Ldsn =[0 0 0 0 0 0] T .

[0099] (5.2) Design an adaptive robust observer to estimate the joint rotation angular velocity and angular acceleration.

[0100] Assume that the observation error e o1 = x2-y, where y is the estimated value of the exoskeleton joint angle. Define a transformation equation:

[0101]

[0102] Among them, e 02 K represents the observation error of the angular velocity of each joint of the exoskeleton. o1 is the positive feedback gain matrix. In this example, take K o1=[40 40 40 40 40 40] T , is the estimated value of the joint angular velocity, the estimated value of the joint angular acceleration Designed to:

[0103]

[0104] Where, and is the estimated value of each matrix, and the estimated value is calculated using another set of parameter estimates K o2 is the linear positive definite feedback gain matrix. In this example, K o2 =[130 130 130 130130 130] T , K o2s is the nonlinear positive definite feedback gain matrix. In this example, K o2s =[0 0 0 0 0 0] T , T os is the observer error adaptive robust feedback term. Let θ q Estimated value of In this example, the initial value The range of estimated values that can be obtained is: make φ o =[-Y o -Y Bo I 6×6 0 6×1 0 6×6 ] T .Y B0 、φ o Denotes the defined variable extraction and transformation respectively. In the adaptive robust observer, the adaptive law We get, where Γ o is a positive definite gain matrix, which is selected as Γ in this embodiment. o =diag{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, The mapping function is:

[0105]

[0106] Where, i is the independent variable,

[0107] The following two conditions are met:

[0108]

[0109] Where, is an estimate Subtract the actual value θ q , ε o is a threshold value and is any non-negative number. In this embodiment, ε is selected o =1, select T os =[0 0 0 0 0 0] T .

[0110] Defining the fourth tracking error in, That is, in the control law F Ld Chinese replace To calculate

[0111] (5.3) Design the desired flow rate Q of the rodless cavity 1m , so that the actual driving force of the hydraulic cylinder F L Ability to track the desired driving force of the hydraulic cylinder estimated in step (5.2) The fourth tracking error Rapidly approaches zero.

[0112] Let Q 1m =Q 1ma +Q 1ms +Q 1msn .Q 1ma , Q 1ms , Q 1msn They represent the model compensation term, linear robust feedback term, and nonlinear robust feedback term respectively. φ 4c =[0 6×16 0 6×6 0 6×6 N2α 2p -q v I 6×6 ] T , α 2p From S7, K4>0 is the linear feedback gain. In this example, K4=[13013013013013040] T φ4=[0 6×16 0 6×6 0 6×6 Q1 1ma +N2α 2p -q v I 6×6 ]T , Q 1msn The following two conditions must be met:

[0113]

[0114] Where, is an estimate Subtract the actual value θ q , ε3 is a threshold value and is any non-negative number; in this embodiment, ε3=1 is selected, and Q is selected. 1msn =[000000] T .

[0115] S6: The expected driving force of the hydraulic cylinders of the supporting leg and the swinging leg in the hydraulic power-assisted exoskeleton during single-leg support obtained in S5 is used as the input of the lower-layer rod cavity pressure planner. The output of the lower-layer rod cavity pressure planner is the expected rod cavity pressure of the hydraulic cylinders of the supporting leg and the swinging leg in the hydraulic power-assisted exoskeleton. The design of the lower-layer rod cavity pressure planner includes the following steps:

[0116] Considering that good control design can ensure that the system error is within a small range, the adaptive model compensation term F Lda Can basically characterize the expected driving force F of the joint hydraulic cylinder Ld In order to obtain a more continuous and smooth rod chamber pressure and avoid the negative influence of noise, the motion reference trajectory is used instead of the measurement signal of the state quantity. Then the expected compensation driving force F of the joint hydraulic cylinder is Ldad =[F Ldad1 F Ldad2 F Ldad3 F Ldad4 F Ldad5 F Ldad6 ] T .

[0117] The desired pressure P of the rod chamber of the i-th hydraulic cylinder 2di Designed to:

[0118]

[0119] Where, P c is the set minimum working pressure. In this example, P c =0.1×10 6 Pa. The derivative of the desired pressure in the rod chamber of the i-th hydraulic cylinder Designed to:

[0120]

[0121] S7: Obtain the actual rod cavity pressure value through the rod cavity pressure sensor of each joint hydraulic cylinder of the supporting leg and the swinging leg; Based on the expected rod cavity pressure of each joint hydraulic cylinder of the supporting leg and the swinging leg in the hydraulic power-assisted exoskeleton during single-leg support obtained in S6, the expected rod cavity pressure and the actual rod cavity pressure are used as inputs of the lower-level rod cavity pressure tracking controller, which outputs the expected rod cavity flow rate of each joint. In this example, the lower-level rod cavity pressure tracking controller method includes the following steps:

[0122] Define the fifth tracking error z 5i =p 2i -p 2di , Q 2i As a virtual control input, Q 2i Design control law α 2pi So that the fifth tracking error z 5i =p 2i -p 2di Rapidly approaches zero;

[0123] Let α 2pi =α 2pai +α 2ps1i +α 2ps2i ,in α 2p =[α 2p1 α 2p2 α 2p3 α 2p4 α 2p5 α 2p6 ] T , K p2i >0 is the linear feedback gain. In this example, take K p21 =K p22 =K p23 =K p24 =K p25 =K p26 =130; They are β e , Δ 4ni The estimated value of θ p2i =[β e Δ 4ni ] T , is θ p2i The estimated value of is in the range of: in is the parameter θ p2i Estimated value of The minimum value of is the parameter θ p2i Estimated value of The maximum value of . Let Estimated value In the lower pressure tracking controller, the adaptive law Get, Γ p2i is a positive definite gain matrix, The mapping function is:

[0124]

[0125] Where, i is the independent variable. Nonlinear robust feedback term α 2ps2i The following two conditions must be met:

[0126]

[0127] in, is an estimate Subtract the actual value θ p2i , ε p2i is a threshold value and is any non-negative number. In this embodiment, ε is selected p2i =1, select α 2ps2i =0.

[0128] S8: The desired rodless flow rate of the hydraulic cylinders in the support and swing leg joints of the hydraulically assisted exoskeleton obtained in S5 and the desired rod-type flow rate of the hydraulic cylinders in the support and swing leg joints of the hydraulically assisted exoskeleton obtained in S7 are used as inputs to the pump-valve flow distribution module. The output of the pump-valve flow distribution module is the control voltage of the electro-hydraulic servo valve 21 of each hydraulic cylinder and the control voltage of the variable speed pump. The pump-valve flow distribution module includes the following steps:

[0129] (8.1) Determine the control voltage u of the variable speed pump corresponding to hydraulic cylinder i pi .

[0130] Step 1: Determine whether the pump provides flow to the rodless chamber of the hydraulic cylinder or to the rod chamber of the hydraulic cylinder.

[0131] If Q 1mi >0,α 2pi ≥0, then sw 1i =1,sw 2i = 0. Among them, Q 1mi and α 2pi It represents the expected flow rate of the rodless chamber and the expected flow rate of the rod chamber of the i-th hydraulic cylinder.

[0132] If Q 1mi >0,α 2pi <0, and if |Q 1madi |≥|α 2padi |, then sw 1i =1,sw 2i =0.

[0133] If Q 1mi >0,α 2pi <0, and if |Q 1madi |<|α 2padi |, then sw 1i =0, sw 2i =1.

[0134] If Q 1mi ≤0,α 2pi ≥0, then sw 1i =0, sw 2i =0.

[0135] If Q 1mi ≤0,α 2pi <0, then sw 1i =0, sw 2i =1.

[0136] Among them, sw 1i and sw 2i They represent the switch state of the switch valve 20 when the flow of the pump control part in the hydraulic cylinder i enters the rodless chamber of the hydraulic cylinder and the switch state of the switch valve 20 when entering the rod chamber of the hydraulic cylinder, respectively. Q 1madi and α 2padi They represent the expected flow of the low-frequency part of the rodless cavity and the rod cavity of the hydraulic cylinder using the joint reference trajectory of the i-th joint. The joint reference trajectory includes the reference rotation angle after the above filtering. Reference angular velocity and the reference angular acceleration The expected flow rate of the low-frequency part is the value calculated by removing the part directly related to the measurement error from the compensation term of the expected flow model of each joint and replacing the actual trajectory with the joint reference trajectory. Specifically, for the rodless cavity expected flow rate Q 1m =Q 1ma +Q 1ms +Q 1msn , the desired flow rate Q of the low-frequency part required by the rodless cavity pump control part 1mad is the compensation term Q for the above adaptive model 1ma The portion directly related to the measurement error is removed (i.e., the term related to the third tracking error z3, which is directly related to the measurement error and has a higher frequency). The remaining portion is calculated using the joint reference trajectory instead of the actual trajectory. Similarly, the desired low-frequency flow rate required for the rodless chamber pump control can be compared to that of the rodless chamber.

[0137] Step 2: Determine the expected output flow rate Q of the pump pdi .

[0138] 1) Calculate Q 1madi and α2padi .

[0139]

[0140] If Q 1mi Q 1madi ≤0, then Q 1madi =0.

[0141] If α 2pi α 2padi ≤0, then α 2padi =0.

[0142] Among them, Q 1madi It's Q 1mad The i-th element of Q 1madi and α 2padi They represent the expected flow of the low-frequency part of the hydraulic cylinder rodless cavity compensation and the expected flow of the low-frequency part of the hydraulic cylinder rod cavity compensation using the joint reference trajectory of the i-th joint, respectively, di represents the motion reference trajectory of hydraulic cylinder i, Q 1mad =[Q 1mad1 ,Q 1mad2 ,Q 1mad3 ,Q 1mad4 ,Q 1mad5 ,Q 1mad6 ] T , α 2pad =[α 2pad1 ,α 2pad2 ,α 2pad3 ,α 2pad4 ,α 2pad5 ,α 2pad6 ] T . N 1d 、φ 4cd 、N 2d 、x di 、V 1di and V 2di is N1, φ 4c , N2, x Li 、V 1i and V 2i Use the reference single leg joint rotation angle and the angular velocity of the single leg joint It is worth mentioning that the values in the above formulas are calculated using the joint reference trajectory instead of the actual trajectory. The reason for using the joint reference trajectory for calculation is, on the one hand, to avoid the influence of state measurement noise, and on the other hand, to avoid the correlation between the state and the measured quantity, thus the frequency is low. Since the pump can only receive low-frequency signals, the filtered joint reference trajectory is used here.

[0143] 2) Calculate Qpdi .

[0144] Q pdi =sw 1i Q 1madi -sw 2i α 2padi .

[0145] If 0≤Q pdi ≤Q pbound , then Q pdi =0.

[0146] Among them, Q pbound Indicates the minimum boundary flow rate when using a variable speed pump. In this example, Q pbound =1×10 - 6 m 3 / s,Q pdi represents the expected output flow of the variable speed pump corresponding to hydraulic cylinder i.

[0147] Step 3: Calculate the control voltage of the pump.

[0148] The control voltage of the variable speed pump corresponding to the hydraulic cylinder i is u pi =Q pdi / k p . Among them, the flow gain coefficient is k p =8.3×10 -5 m 3 / (s·V).

[0149] (8.2) Determine the control voltage u of the servo valve corresponding to hydraulic cylinder i pv1i ,u pv2i ,u pv3i ,u pv4i .

[0150] Q 1pdi =sw 1i Q pdi , Q 2pdi =sw 2i Q pdi , Q 1vdi =Q 1mi -Q 1pdi , Q 2vdi =α 2pi +Q 2pdi , where Q 1pdi and Q 2pdi

[0151] They represent the expected oil flow rate of the rodless chamber and the rod chamber from the pump control part in the hydraulic cylinder i, respectively, and Q 1vdi and Q 2vdiThey represent the expected oil inlet flow rate of the rodless chamber and the expected oil outlet flow rate of the rod chamber from the valve control part in the hydraulic cylinder i respectively.

[0152] If Q 1vdi >0, then u pv3i =0.

[0153] If Q 1vdi <0, then u pv1i =0,

[0154] If Q 1vdi =0, then u pv1i =0,u pv3i =0.

[0155] If Q 2vdi >0, then u pv2i =0,

[0156] If Q 2vdi <0, then u pv4i =0.

[0157] If Q 2vdi =0, then u pv2i =0,u pv4i =0.

[0158] in,

[0159] In summary, the control input signals of the pump control part and the valve control part can be obtained.

[0160] S9: The control voltage obtained in S8 is converted into a corresponding control current through the amplifier board of each joint's variable speed pump and electro-hydraulic servo valve 21. The operating status of the variable speed pump and electro-hydraulic servo valve 21 is controlled according to the current signal to control the pressure at both ends of the hydraulic cylinder. The combination of the two jointly drives the movement of each hydraulic cylinder, and then drives the rotation of each joint of the double-leg hydraulic power-assisted exoskeleton to realize the follow-up movement of the double-leg hydraulic power-assisted exoskeleton.

[0161] In another embodiment, a high-precision, high-efficiency control system for a single-leg support hydraulically assisted exoskeleton is proposed, which utilizes the force control method described above for a single-leg support hydraulically assisted exoskeleton. This high-precision, high-efficiency control system includes a data acquisition module, an initialization module, a motion state determination module, a model building module, a data processing module, a signal generation module, and a tracking control module.

[0162] The data acquisition module is used to acquire the state data of the exoskeleton. The state data includes characteristic data and motion data. The motion data includes: back force, foot force, actual angle values of each exoskeleton joint, actual pressure of the right leg ankle joint hydraulic cylinder 2, actual pressure of the right leg knee joint hydraulic cylinder 14, actual pressure of the right leg hip joint hydraulic cylinder 6, actual pressure of the left leg ankle joint hydraulic cylinder 11, actual pressure of the left leg knee joint hydraulic cylinder 13, actual pressure of the left leg hip joint hydraulic cylinder 16, left foot support force, and right foot support force. Characteristic data includes: human-machine interface stiffness, waist stiffness, leg and foot stiffness, chamber volume of the hydraulic cylinder, and damping coefficients of each joint. The data acquisition module may include multiple sensors, including a back force sensor, an exoskeleton actual angle sensor, an ankle joint hydraulic cylinder actual pressure sensor, a knee joint hydraulic cylinder actual pressure sensor, a hip joint hydraulic cylinder actual pressure sensor, and a foot support force sensor.

[0163] The initialization module is used to initialize the controller's sampling period, which is set between 10 and 20 milliseconds. It also controls the rotation of the footrest to a horizontal position and the rotation of the first and second rods, as well as the back, to a vertical position. It also initializes multiple sensors and resets each sensor's value to zero.

[0164] The motion state determination module is used to determine the motion state of the left and right legs and to modify the feature data in real time based on the motion state. This motion state determination is achieved through the following strategy: It is used to determine whether the left and right legs are exerting pressure on the ground. If so, the left leg, right leg, or both legs are used as the supporting leg; otherwise, the left or right leg is used as the swing leg.

[0165] The model building module is used to build the physical model of the exoskeleton and convert it into a state equation based on the characteristic data. This physical model includes the human-machine interface model for the contact points between the user and the exoskeleton back and the swinging leg foot, the exoskeleton's motion model during single-leg support, and the dynamics model of the hydraulic actuator.

[0166] The data processing module is used to obtain the reference trajectory of the exoskeleton in the upper controller based on the back force and the swing leg foot force. The back force can be obtained by real-time monitoring using the back force sensor installed on the backboard 19. The swing leg foot force can be obtained by real-time monitoring using the foot force sensor installed on the footboard. The actual angle value can be obtained by real-time monitoring using the exoskeleton actual angle sensor installed at each joint. Based on the reference angle and the actual angle, the desired driving force of the exoskeleton support leg and swing leg hydraulic cylinders and the desired flow rate of the hydraulic cylinder rodless cavity are obtained in the lower rodless cavity position tracking controller. The data processing module is also used to obtain the actual output force of the support leg and swing leg ankle joint hydraulic cylinders in the dynamic model of the hydraulic driver based on the actual pressure of the support leg and swing leg ankle joint hydraulic cylinders, obtain the actual output force of the support leg and swing leg knee joint hydraulic cylinders in the dynamic model of the hydraulic driver based on the actual pressure of the support leg and swing leg knee joint hydraulic cylinders, and obtain the actual output force of the support leg and swing leg hip joint hydraulic cylinders in the dynamic model of the hydraulic driver based on the actual pressure of the support leg and swing leg hip joint hydraulic cylinders. The desired rodless cavity flow rate can be determined based on the desired driving torque of each joint, the actual output force of the hydraulic cylinders for the ankle joint of the supporting leg and the swing leg, the actual output force of the hydraulic cylinders for the knee joint of the supporting leg and the swing leg, and the actual output force of the hydraulic cylinders for the hip joint of the supporting leg and the swing leg. The rodless cavity pressure planner can then be used to plan the rodless cavity pressure based on the hydraulic cylinder output force to obtain the desired rodless cavity pressure. The rodless cavity pressure tracking controller can then track the desired rodless cavity pressure to obtain the desired rodless cavity flow rate.

[0167] The signal generation module is used to generate control voltage signals for the variable speed pumps and servo valves of each joint based on the desired flow rates of the rodless and rod chambers of the hydraulic cylinders of the exoskeleton's support and swing legs. This flow distributor generates corresponding current signals based on the voltage signals from the variable speed pumps and servo valves.

[0168] The tracking control module controls the rotation of the exoskeleton's joints based on current signals, enabling real-time trajectory tracking. The electro-hydraulic servo valve 21 receives current as input and flow as output. The variable-speed pump receives the current signal to drive the motor, while the electro-hydraulic servo valve 21 receives the current to drive the valve core opening. Together, these two control the pressure at each hydraulic cylinder, driving its movement and enabling real-time trajectory tracking of the exoskeleton.

[0169] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0170] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A force control method for a single-leg support hydraulically assisted exoskeleton, characterized in that: The invention is used to control a hydraulically assisted exoskeleton in a single-leg support state. The hydraulically assisted exoskeleton comprises: a left leg and a right leg with identical structures, each of which is provided with three hydraulic cylinders for controlling the rotation of the corresponding ankle joint, knee joint, and hip joint. The invention comprises the following steps: Step 1: Obtain the state data of the exoskeleton in the single-leg support state, and determine the motion state of the left and right legs respectively, thereby determining the swing leg and support leg of the exoskeleton, and correct the state data in real time according to the motion state; Step 2: Establish a physical model of the exoskeleton in the single-leg support state, and construct an upper-layer controller and a lower-layer controller based on the physical model; Step 3: Based on the upper and lower controllers, the control voltages of the variable speed pumps and servo valves used to drive the hydraulic cylinders of the exoskeleton joints in the single-leg support state are obtained; Step 4: Generate a corresponding current signal based on the control voltage to control the corresponding variable speed pump and servo valve, thereby controlling the pressure at both ends of the hydraulic cylinder, realizing the movement of the hydraulic cylinder and driving the rotation of each joint in the single-leg support state of the exoskeleton.

2. The force control method of a single-leg support hydraulic power-assisted exoskeleton according to claim 1, characterized in that: In step 3, the method for obtaining the control voltage includes the following steps: First, the reference trajectory of the exoskeleton support leg and the swing leg is obtained in the upper controller according to the back force and the foot force of the swing leg; then, the expected driving force and the expected flow rate of the rodless cavity of the hydraulic cylinder of each joint of the exoskeleton support leg and the swing leg are obtained in the lower controller according to the reference trajectory; then, the expected pressure of the rod cavity of each joint of the hydraulic cylinder of the exoskeleton support leg and the swing leg is obtained in the lower controller according to the expected driving force of each joint hydraulic cylinder; then, the expected flow rate of the rod cavity of each joint hydraulic cylinder of the exoskeleton support leg and the swing leg is obtained in the lower controller according to the expected pressure of the rod cavity; finally, the control voltage of the variable speed pump and servo valve of each joint of the exoskeleton support leg and the swing leg is obtained in the lower controller according to the expected flow rate of the rodless cavity and the expected flow rate of the rod cavity; The lower-level controller includes: The lower layer rodless cavity position tracking controller is used to calculate the desired driving force of the hydraulic cylinders of each joint of the exoskeleton support leg and the swing leg and the desired flow rate of the rodless cavity; The lower layer has a rod cavity pressure planner, which is used to calculate the desired pressure in the rod cavity of the hydraulic cylinder of each joint of the exoskeleton support leg and swing leg; The lower layer has a rod cavity pressure tracking controller, which is used to calculate the desired flow rate of the rod cavity of the hydraulic cylinder of each joint of the exoskeleton support leg and swing leg; The flow distributor is used to calculate the control voltage of the variable speed pumps and servo valves in each joint of the exoskeleton's supporting and swinging legs.

3. The force control method of a single-leg support hydraulic power-assisted exoskeleton according to claim 2, characterized in that: The method for the lower-layer rodless cavity position tracking controller to calculate the expected driving force of the hydraulic cylinders of each joint of the exoskeleton support leg and the swing leg and the expected flow of the rodless cavity includes the following steps: Assume the second tracking error in Define a transformation equation: Among them, K2 takes any non-negative number, is the first-order derivative of z2, q r Represents the intermediate variables defined when generating the desired angular velocity and angular acceleration of each joint. q r The first derivative of , z3 is the third tracking error; Indicates the reference angle of the joint in the single-leg support state; represents the estimated reference angular velocity of the joint in the single-leg support state; Let Bx3 = Y B B θ , Where β is the model parameter of the mechanical structure, B θ =[B1 B2 B3 B4 B5 B6] T Y is the matrix of joint damping coefficients, where B1, B2, B3, B4, B5, and B6 represent the damping coefficients of the ankle joint of the supporting leg, the knee joint of the supporting leg, the hip joint of the supporting leg, the hip joint of the swinging leg, the knee joint of the swinging leg, and the ankle joint of the swinging leg, respectively; B The diagonal matrix representing the actual angular velocity of each joint, f0 and Y represent the terms obtained by linearizing the parameters on the left side of the equal sign in the formula; F L As a virtual control input, F L Design control law F Ld Make the second tracking error z2 quickly approach zero: Let F Ld =F Lda +F Lds +F Ldsn ,in, F Lds =-h -1 K3z3, K3 is the linear feedback gain, They are β, B θ , Δ 2n The estimated value of the concentration parameter θ is defined q =[β T B θ T Δ 2n T β e Δ 3n T ] T , For the parameter θ q Estimated value of The minimum value of For the parameter θ q Estimated value of The maximum value of θ qmaxi ,θ qmini are θ q The maximum and minimum values of the i-th element, estimated value In the lower rodless cavity position tracking controller, the adaptive law We obtain that Γ2 is a positive definite gain matrix, The mapping function is: Where, i is the independent variable, for The i-th parameter of , let φ3=[-Y -Y B I 6×6 0 6×1 0 6×6 ] T ; Design an adaptive robust observer to estimate the joint rotation angular velocity and angular acceleration: Let the observation error e o1 =x²-y, where y is the estimated value of the exoskeleton joint angle, and a conversion equation is defined: Among them, e 02 represents the observation error of the angular velocity of each joint of the exoskeleton, K o1 is the positive definite feedback gain matrix, is the estimated value of the joint angular velocity, the estimated value of the joint angular acceleration Designed to: Where, and is the estimated value of each matrix, and the estimated value is calculated using another set of parameter estimates K o2 is the linear positive definite feedback gain matrix, K o2s is the nonlinear positive definite feedback gain matrix, T os is the observer error adaptive robust feedback term, let The estimated range is: make φ o =[-Y o -Y Bo I 6×6 0 6×1 0 6×6 ] T ; Estimated value In the adaptive robust observer, the adaptive law We get, where Γ o is a positive definite gain matrix, The mapping function is: Where, i is the independent variable, Defining the fourth tracking error in, In the control law F Ld Chinese replace To calculate Design the expected flow rate Q of the rodless cavity 1m , so that the actual driving force of the hydraulic cylinder F L Ability to track estimated desired hydraulic cylinder actuation force Make the fourth tracking error Rapidly approaches zero; Let Q 1m =Q 1ma +Q 1ms +Q 1msn , φ 4c =[0 6×16 0 6×6 0 6×6 N2α 2p -q v I 6×6 ] T , K4>0 is the linear feedback gain, φ4=[0 6×16 0 6×6 0 6×6 Q1 1ma +N2α 2p -q v I 6×6 ] T , 4. The force control method for a single-leg support hydraulically assisted exoskeleton according to claim 2, characterized in that: The method for the lower-layer rod cavity pressure planner to calculate the expected pressure of the rod cavity of the hydraulic cylinder of each joint of the exoskeleton support leg and swing leg includes the following steps: The motion reference trajectory is used to replace the measurement signal of the state quantity to obtain the expected compensation driving force F of the joint hydraulic cylinder. Ldad =[F Ldad1 F Ldad2 F Ldad3 F Ldad4 F Ldad5 F Ldad6 ] T ; The desired pressure P of the rod chamber of the i-th hydraulic cylinder 2di Designed to: Where, P c is the set minimum working pressure; the derivative of the desired pressure in the rod chamber of the i-th hydraulic cylinder Designed to:

5. The force control method of a single-leg support hydraulic power-assisted exoskeleton according to claim 2, characterized in that: The method for the lower-layer rod cavity pressure tracking controller to calculate the expected flow rate of the rod cavity of the hydraulic cylinder of each joint of the exoskeleton support leg and the swing leg includes the following steps: Define the fifth tracking error z 5i =p 2i -p 2di , Q 2i As a virtual control input, Q 2i Design control law α 2pi So that the fifth tracking error z 5i =p 2i -p 2di Rapidly approaches zero: Let α 2pi =α 2pai +α 2ps1i +α 2ps2i ,in α 2p =[α 2p1 α 2p2 α 2p3 α 2p4 α 2p5 α 2p6 ] T , K p2i >0 is linear feedback gain, They are β e , Δ 4ni The estimated value of θ p2i =[β e Δ 4ni ] T , is θ p2i The estimated value of is in the range of: in is the parameter θ p2i Estimated value of The minimum value of is the parameter θ p2i Estimated value of The maximum value of Estimated value In the lower rod cavity pressure tracking controller, the adaptive law Get, Γ p2i is a positive definite gain matrix, The mapping function is: Where, i is the independent variable.

6. The force control method for a single-leg support hydraulically assisted exoskeleton according to claim 2, characterized in that: The method for the flow distributor to calculate the variable speed pumps of each joint of the exoskeleton support leg and the swing leg includes the following steps: S61. Determine whether the variable speed pump provides flow to the rodless chamber or the rod chamber of the hydraulic cylinder: If Q 1mi >0,α 2pi ≥0, then sw 1i =1,sw 2i =0; If Q 1mi >0,α 2pi <0, and if |Q 1madi |≥|α 2padi |, then sw 1i =1,sw 2i =0; If Q 1mi >0,α 2pi <0, and if |Q 1madi |<|α 2padi |, then sw 1i =0, sw 2i =1; If Q 1mi ≤0,α 2pi ≥0, then sw 1i =0, sw 2i =0; If Q 1mi ≤0,α 2pi <0, then sw 1i =0, sw 2i =1; Among them, sw 1i and sw 2i They represent the switch state of the switch valve when the flow of the pump control part in the hydraulic cylinder i enters the rodless chamber of the hydraulic cylinder and the switch state of the switch valve when entering the rod chamber of the hydraulic cylinder, respectively. Q 1madi and α 2padi They represent the expected flow of the low-frequency part of the rodless cavity and rod cavity compensation of the hydraulic cylinder using the joint reference trajectory of the i-th joint respectively; S62. Determine the expected output flow Q of the variable speed pump pdi : First calculate the expected flow Q of the low-frequency part of the hydraulic cylinder rodless cavity compensation using the joint reference trajectory of the i-th joint 1madi and the desired flow rate α of the low-frequency part of the hydraulic cylinder rod cavity compensation 2padi : If Q 1mi Q 1madi ≤0, then Q 1madi =0; If α 2pi α 2padi ≤0, then α 2padi =0; Among them, Q 1madi It's Q 1mad The i-th element, x di represents the motion reference trajectory of hydraulic cylinder i, Q 1mad =[Q 1mad1 ,Q 1mad2 ,Q 1mad3 ,Q 1mad4 ,Q 1mad5 ,Q 1mad6 ] T , α 2pad ＝[α 2pad1 ,α 2pad2 ,α 2pad3 ,α 2pad4 ,α 2pad5 ,α 2pad6 ] T ； Calculate Q again pdi :Q pdi =sw 1i Q 1madi -sw 2i α 2padi ; If 0≤Q pdi ≤Q pbound , then Q pdi =0; Among them, Q pbound Indicates the minimum boundary flow rate when using a variable speed pump, Q pdi represents the expected output flow of the variable speed pump corresponding to hydraulic cylinder i; S63, according to Q pdi Calculate the control voltage u of the variable speed pump pi , the calculation formula is u pi =Q pdi / k p .

7. The force control method for a single-leg support hydraulically assisted exoskeleton according to claim 1, characterized in that: In step 2, the physical model includes the dynamic model of the hydraulic actuator; the dynamic model is: Q 1i =Q 1vi +Q 1pi ,Q 2i =Q 2vi -Q 2pi Q 1vi =Q pv1i -Q pv3i ,Q 2vi =-Q pv2i +Q pv4i ΔP pv1i =P s -P 1i ,ΔP pv2i =P s -P 2i ,ΔP pv3i =P 1i -P r ,ΔP pv4i =P 2i -P r Q 1pi =sw 1i Q pi ,Q 2pi =sw 2i Q pi Q pi =k pi u pi ,i=1,2,…6 Where, β e represents the bulk modulus, Q 1i , Q 2i are the oil inlet flow rate of the rodless chamber and the oil outlet flow rate of the rod chamber in the hydraulic cylinder i, and represents the concentrated modeling error and uncertain disturbance in the hydraulic actuator dynamics model, Q 1vi and Q 2vi They represent the oil flow rate from the rodless chamber to the valve control part and the oil flow rate from the rod chamber in the hydraulic cylinder i, respectively. 1pi and Q 2pi They represent the oil flow rate of the rodless chamber and the rod chamber from the pump control part in the hydraulic cylinder i, respectively, and Q pvji represents the flow rate of the jth servo valve corresponding to the hydraulic cylinder i, k qpvji is the flow gain coefficient of the jth servo valve corresponding to the hydraulic cylinder i, x pvji is the valve core displacement of the jth servo valve corresponding to hydraulic cylinder i, P s With P r They are the oil supply pressure of the valve control part and the pressure of the oil tank, ΔP pv1i and ΔP pv2i Respectively represent the oil supply pressure P of the valve control part in the hydraulic cylinder i s The actual pressure of the rodless chamber P 1i And the actual pressure of the rod chamber P 2i The pressure difference, ΔP pv3i and ΔP pv4i They represent the actual pressure P in the rodless chamber of hydraulic cylinder i. 1i And the actual pressure of the rod chamber P 2i With the tank pressure P r The pressure difference, u pvji is the control voltage of the jth servo valve corresponding to hydraulic cylinder i, Q pi represents the output flow of the variable speed pump corresponding to the hydraulic cylinder i, k pi and u pi They represent the flow gain coefficient and control voltage of the variable speed pump corresponding to the hydraulic cylinder i respectively.

8. The force control method for a single-leg support hydraulically assisted exoskeleton according to claim 2, characterized in that: The method for the flow distributor to calculate the servo valves of each joint of the exoskeleton support leg and the swing leg includes the following steps: Determine the control voltage u of the servo valve corresponding to the hydraulic cylinder i pv1i ,u pv2i ,u pv3i ,u pv4i :Q 1pdi =sw 1i Q pdi , Q 2pdi =sw 2i Q pdi , Q 1vdi =Q 1mi -Q 1pdi , Q 2vdi =α 2pi +Q 2pdi , where Q 1pdi and Q 2pdi They represent the expected oil flow rate of the rodless chamber and the rod chamber from the pump control part in the hydraulic cylinder i, respectively, and Q 1vdi and Q 2vdi They represent the expected oil inlet flow rate of the rodless chamber and the expected oil outlet flow rate of the rod chamber from the valve control part in the hydraulic cylinder i respectively; If Q 1vdi >0, then u pv3i =0; If Q 1vdi <0, then u pv1i =0, If Q 1vdi =0, then u pv1i =0,u pv3i =0; If Q 2vdi >0, then u pv2i =0, If Q 2vdi <0, then u pv4i =0; If Q 2vdi =0, then u pv2i =0,u pv4i =0.

9. A high-precision, high-energy-efficiency control system for a single-leg support hydraulically assisted exoskeleton, comprising: The data acquisition module is used to obtain the state data of the exoskeleton in the single-leg support state, and to determine the movement state of the left and right legs respectively, thereby determining the swing leg and the support leg of the exoskeleton, and to correct the state data in real time according to the movement state; A model building module, which is used to establish a physical model of the exoskeleton in the single-leg support state and construct an upper-layer controller and a lower-layer controller based on the physical model; A signal generation module, which is used to obtain the control voltage of the variable speed pump and servo valve used to drive the hydraulic cylinder of each joint in the exoskeleton in the single-leg support state based on the upper controller and the lower controller, and then generate the corresponding current signal; The tracking control module is also used to control the corresponding variable speed pump and servo valve based on the current signal, thereby controlling the pressure at both ends of the hydraulic cylinder, realizing the movement of the hydraulic cylinder and driving the rotation of each joint in the single-leg support state of the exoskeleton.

10. A hydraulically assisted lower limb exoskeleton, characterized in that: It is controlled using the force control method of a single-leg support hydraulically assisted exoskeleton according to any one of claims 1 to 8; the lower limb hydraulically assisted exoskeleton comprises: Back panel; A left bottom plate and a right bottom plate, which are connected to the bottom of the back plate; A left thigh rod and a right thigh rod are rotatably connected to the bottom of the left bottom plate and the bottom of the right bottom plate respectively; A left calf rod and a right calf rod are rotatably connected to the ends of the left thigh rod and the right thigh rod away from the back plate respectively; The left foot plate and the right foot plate are rotatably connected to the ends of the left calf rod and the right calf rod away from the back plate respectively; The left leg hip joint hydraulic cylinder and the right leg hip joint hydraulic cylinder are used to drive the relative rotation between the back plate and the left thigh rod and the back plate and the right thigh rod respectively; The left leg knee joint hydraulic cylinder and the right leg knee joint hydraulic cylinder are used to drive the left thigh rod and the left shank rod to rotate relative to each other, and the right thigh rod and the right shank rod to rotate relative to each other; The left leg ankle joint hydraulic cylinder and the right leg ankle joint hydraulic cylinder are used to drive the left calf rod and the left foot plate to rotate relative to each other, and the right calf rod and the right foot plate to rotate relative to each other; A plurality of variable speed pumps, switching valves and servo valves, which are used to drive the movement of the right leg ankle joint hydraulic cylinder, the right leg knee joint hydraulic cylinder, the right leg hip joint hydraulic cylinder, the left leg ankle joint hydraulic cylinder, the left leg knee joint hydraulic cylinder and the left leg hip joint hydraulic cylinder; Multiple sensors for collecting status data of the exoskeleton; The real-time controller is used to output the hydraulic cylinder control quantity according to the state data and control the operating state of each hydraulic cylinder according to the hydraulic cylinder control quantity.

Images