Method, system and equipment for controlling preset performance of upper limb exoskeleton system and medium

Abstract

The invention provides an upper limb exoskeleton system preset performance control method, system and device and a medium, and belongs to the technical field of exoskeleton control, and the method comprises the following steps: obtaining the angle and control torque of a wrist joint of a two-degree-of-freedom upper limb exoskeleton system, and building a kinetic model of the two-degree-of-freedom upper limb exoskeleton system, constructing a state space expression according to the dynamic model; setting constraint boundaries of the angle of the wrist joint at different moments, and constructing a control obstacle function according to the constraint boundaries; acquiring a reference trajectory of an expected joint angle and an angular velocity of the two-degree-of-freedom upper limb exoskeleton system, designing a sliding mode surface according to a reference trajectory tracking error, and designing a switching controller based on the sliding mode surface and a control obstacle function; and inputting the reference trajectory and the switching controller into the state space expression to obtain angles, angular velocities, angle errors and angular velocity errors of the wrist joint of the upper limb exoskeleton system at different moments. The invention can provide control precision.

Description

Technical Field

[0001] The present invention belongs to the field of exoskeleton control technology, and specifically relates to a method, system, device and medium for controlling preset performance of an upper limb exoskeleton system. Background Art

[0002] An upper-limb exoskeleton system is a wearable mechanical device that acts as a force support to assist humans in completing strenuous physical tasks. It also serves as a medical rehabilitation device, assisting disabled individuals in rehabilitation training. It holds significant practical value in military and medical fields. The basic operating principle of an upper-limb exoskeleton system is to provide specific torques to specific joints based on the desired movement. This allows for real-time adjustment of the position and angle of each joint in the exoskeleton robot, enabling rapid and accurate tracking of arm movements. The exoskeleton system and the wearer form a typical human-robot collaborative system characterized by multivariable, nonlinear, and uncertain characteristics, making it susceptible to mechanical and sensor errors, as well as external interference. To ensure synchronized movement between the human body and the robot, the exoskeleton system must be designed not only to conform to human ergonomics but also to provide accurate tracking capabilities to ensure the wearer's comfort and safety.

[0003] Preset performance control refers to a control strategy that aims to improve system safety and stability by constraining the system's state to maintain it within predetermined, safe boundaries. Traditional preset performance control uses the Lyapunov function, which can only ensure that the initial state of the joint is within the bounds of the constraints, but cannot guarantee that it will remain within the constraints during the system's evolution (especially during long-term operation). In other words, the system may violate these boundaries in certain situations, resulting in safety risks. Summary of the Invention

[0004] In order to overcome the above-mentioned deficiencies in the prior art, the present invention provides a method for controlling preset performance of an upper limb exoskeleton system, comprising the following steps:

[0005] Obtain the angle and control torque of the wrist joint of the two-degree-of-freedom upper limb exoskeleton system, establish a dynamic model of the two-degree-of-freedom upper limb exoskeleton system based on the angle and control torque of the wrist joint, and construct a state space expression based on the dynamic model;

[0006] Based on the dynamic model, setting constraint boundaries of the wrist joint angle at different times, and constructing a control obstacle function according to the constraint boundaries;

[0007] Obtaining reference trajectories of desired joint angles and angular velocities of a two-degree-of-freedom upper limb exoskeleton system, designing a sliding surface based on tracking errors of the reference trajectories of desired joint angles and angular velocities, and designing a synovial controller based on the sliding surface and a control obstacle function;

[0008] The reference trajectory of the desired joint angle and angular velocity of the two-degree-of-freedom upper limb exoskeleton system and the synovial controller are input into the state space expression to obtain the angle, angular velocity, angle error and angular velocity error of the wrist joint of the upper limb exoskeleton system at different times. The preset performance of the upper limb exoskeleton system is controlled by the angle, angular velocity, angle error and angular velocity error of the wrist joint of the upper limb exoskeleton system at different times.

[0009] Preferably, the wrist joint includes a wrist internal and external rotation joint and a wrist flexion and extension joint.

[0010] Preferably, the kinetic model is as follows:

[0011]

[0012] where θ = [θ1, θ2] T is the exoskeleton joint angle vector, and θ1 and θ2 are the angles of the wrist internal and external rotation joints and wrist flexion-extension joints, respectively; and Represent the joint angular velocity and angular acceleration vector of the upper limb exoskeleton respectively; M(θ)∈R 2×2 is a positive definite symmetric inertia matrix; is the centrifugal force and Coriolis force matrix; G(θ)∈R 2×1 represents the gravity vector; τ=[τ1,τ2] T represents the control torque vector, τ1 and τ2 represent the control torques of the wrist internal and external rotation joints and wrist flexion and extension joint actuators of the upper limb exoskeleton, respectively; τ ex Represents the external lumped disturbance vector of the exoskeleton system.

[0013] Preferably, the state space expression is as follows:

[0014]

[0015] Where x1 = θ, u=M -1 (x1)τ is the actual control input, d=-M -1 (x1)τ ex is the external aggregate interference.

[0016] Preferably, the control barrier function is as follows:

[0017] h1(t,e1)=||e1(t)||+p1(t), h2(t,e1)=p2(t)-||e1(t)||;

[0018] Where e1(t) is the angle tracking error, and p1(t) and p2(t) are predefined smoothing performance functions.

[0019] Preferably, the sliding mode controller is as follows:

[0020]

[0021] Where c1,η is a constant greater than zero, e1 is the angle tracking error, e2 is the angular velocity tracking error, and are the expected angular velocity trajectories of the wrist internal and external rotation joints and the wrist flexion and extension joints, D is the upper bound of the external disturbance, s is the sliding surface, and f = -M -1 (x1)[C(x1,x2)x2+G(x1)], x1=θ, l1 and l2 are positive constants to be designed, h1 is the control obstacle function, p1 is the predefined smooth performance function, sign(s) is the sign function, and χ0, χ1, and χ2 are all defined region sets.

[0022] The present invention also provides an upper limb exoskeleton system preset performance control system, comprising:

[0023] A state space expression acquisition module is used to obtain the angle and control torque of the wrist joint of the two-degree-of-freedom upper limb exoskeleton system, establish a dynamic model of the two-degree-of-freedom upper limb exoskeleton system based on the angle and control torque of the wrist joint, and construct a state space expression based on the dynamic model;

[0024] A control obstacle function construction module is used to set the constraint boundaries of the wrist joint angle at different times based on the dynamic model, and construct a control obstacle function according to the constraint boundaries;

[0025] a sliding mode controller design module for obtaining a reference trajectory of desired joint angles and angular velocities of a two-degree-of-freedom upper limb exoskeleton system, designing a sliding mode surface based on a tracking error of the reference trajectory of desired joint angles and angular velocities, and designing a sliding mode controller based on the sliding mode surface and a control obstacle function;

[0026] The control module is used to input the reference trajectory of the desired joint angle and angular velocity of the two-degree-of-freedom upper limb exoskeleton system and the synovial controller into the state space expression, obtain the angle, angular velocity, angle error and angular velocity error of the wrist joint of the upper limb exoskeleton system at different times, and control the preset performance of the upper limb exoskeleton system through the angle, angular velocity, angle error and angular velocity error of the wrist joint of the upper limb exoskeleton system at different times.

[0027] The present invention also provides a computer device comprising a memory and a processor; the memory stores a computer program, and the processor is used to run the computer program in the memory to execute the preset performance control method of the upper limb exoskeleton system.

[0028] The present invention also provides a computer-readable storage medium, which stores a computer program. The computer program is suitable for being loaded by a processor to execute the preset performance control method of the upper limb exoskeleton system.

[0029] The upper limb exoskeleton system preset performance control method provided by the present invention has the following beneficial effects:

[0030] The present invention is based on a constructed dynamic model that can set constraint boundaries for the angle of the wrist joint at different times, and can construct a control obstacle function based on the constraint boundaries; a sliding surface can be designed through the reference trajectory tracking error of the expected joint angle and angular velocity, and a synovial controller is designed based on the sliding surface and the control obstacle function. The synovial controller designed by the sliding surface and the control obstacle function can enable the upper limb exoskeleton system to converge to the safety set even when it is outside the safety set during operation; in addition, the sliding mode controller can enable the system state to converge to zero over time after converging to the safety set, thereby solving the safety problem of the upper limb exoskeleton system during movement. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] To more clearly illustrate the embodiments of the present invention and its design, the following briefly introduces the drawings required for this embodiment. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be derived from these drawings without inventive effort.

[0032] Figure 1 It is the motion trajectory diagram and structural diagram of the two-degree-of-freedom upper limb exoskeleton system; Figure 1 (a) is a schematic diagram of the structure of a two-degree-of-freedom upper limb exoskeleton system; Figure 1 (b) Schematic diagram of the motion trajectory analysis of each joint position of the two-degree-of-freedom upper limb exoskeleton system;

[0033] Figure 2 This is a control block diagram of a sliding mode control strategy based on a control barrier function according to an embodiment of the control strategy of the present invention;

[0034] Figure 3 A flowchart of the steps of an embodiment of the control strategy of the present invention;

[0035] Figure 4 is the simulation result of the control strategy of the present invention, where: Figure 4 (a) is the tracking trajectory curve of the elbow joint of the two-degree-of-freedom upper limb exoskeleton system. Figure 4 (b) is the tracking trajectory curve of the wrist joint;

[0036] Figure 5 is the simulation result of the angular velocity tracking error of the present invention, Figure 5(a) is the simulation diagram of wrist joint angle tracking error. Figure 5 (b) is the simulation diagram of angular velocity tracking error;

[0037] Figure 6 is the simulation result of the angle tracking error of the present invention, Figure 6 (a) is the changing curve of the designed control obstacle function, Figure 6 (b) is the simulation result of the angle norm error of the two constrained joints;

[0038] Figure 7 (a) is the simulation result diagram of wrist joint angle constraint. Figure 7 (b) is the simulation result diagram of elbow joint angle constraint;

[0039] Figure 8 This is the control input simulation result diagram;

[0040] Figure 9 This is the phase plane simulation result diagram of the two joint angles and angular velocity states changing with time.

[0041] Description of reference numerals:

[0042] 1-First joint motor; 2-First gear; 3-Second gear; 4-First joint right-angle connecting rod; 5-Z-type connecting rod; 6-Second joint motor; 7-Handle. DETAILED DESCRIPTION

[0043] In order to enable those skilled in the art to better understand the technical solution of the present invention and to be able to implement it, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments. The following embodiments are only used to more clearly illustrate the technical solution of the present invention and are not intended to limit the scope of protection of the present invention.

[0044] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the technical solutions of the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0045] In addition, the terms "first", "second", etc. are used for descriptive purposes only and are not to be understood as indicating or implying relative importance. In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meaning of the above terms in the present invention can be understood according to the specific circumstances. In the description of the present invention, unless otherwise specified, "plurality" means two or more, which will not be described in detail here.

[0046] Example

[0047] The structural diagram and motion trajectory analysis diagram of the upper limb exoskeleton system of the present invention are as follows: Figure 1 As shown, Figure 1 (a) is a schematic diagram of the structure of a two-degree-of-freedom upper limb exoskeleton system; Figure 1 (b) is a schematic diagram of the motion trajectory analysis of each joint position of the two-degree-of-freedom upper limb exoskeleton system; Figure 1 As shown in (a), the wrist internal and external rotation joint includes a first joint motor 1, a first gear 2 and a second gear 3, a bearing, and a Z-shaped connecting rod 5. The connecting rod fixed on the first joint motor 1 is fastened to the slider of the forearm telescopic mechanism by means of bolts and nuts; the first gear 2 nested on the first joint motor 1 is engaged with the second gear 3 on the lower side of the bearing; the first joint right-angle connecting rod 4 with a groove is fixed to the side of the outer shell in the middle of the annular ring of the bearing; the wrist flexion and extension joint part includes a second joint motor 6, a Z-shaped connecting rod 5 and a handle 7; the Z-shaped connecting rod 5 fixed on the second joint motor 6 is locked with the first joint right-angle connecting rod 4 fixed on the upper side of the annular outer shell of the bearing by means of bolts and nuts; the tail end of the second joint motor 6 is connected to the handle 7 through the Z-shaped connecting rod 5; the second joint motor 6 drives the handle 7 to rotate. As shown Figure 1 As shown in (b), the inter-joint links (a, b, c, e in the figure) have uniform texture, and their center of mass p 11 、p 12 、p 21 、p 22 The cylinders M1 and M2 in the figure represent the wrist internal and external rotation drive units and the wrist flexion and extension drive units, respectively. Their masses act evenly on the links. l1 is the longitudinal distance from the center of M1 to the center of M2, l2 is the distance from the center of M2 to the end of the exoskeleton, d1 is the transverse distance from the center of M1 to the center of M2, and d2 is the length of the end handle. The positions of the wrist internal and external rotation joints and the wrist flexion and extension joints are shown in Figure 1 S1 and S2 in (b).

[0048] In this embodiment, based on the above-mentioned upper limb exoskeleton system, the upper limb exoskeleton system preset performance control method of the present invention includes the following steps:

[0049] Step 1: Obtain the angle and control torque of the wrist joint of the two-degree-of-freedom upper limb exoskeleton system, establish a dynamic model of the two-degree-of-freedom upper limb exoskeleton system based on the angle and control torque of the wrist joint, and construct a state space expression based on the dynamic model.

[0050] Step 2: Based on the dynamic model, set the constraint boundaries of the wrist joint angle at different times, and construct a control obstacle function based on the constraint boundaries.

[0051] Step 3: Obtain the reference trajectory of the desired joint angle and angular velocity of the two-degree-of-freedom upper limb exoskeleton system, design a sliding surface according to the tracking error of the reference trajectory of the desired joint angle and angular velocity, and design a synovial controller based on the sliding surface and the control obstacle function.

[0052] Step 4: Input the reference trajectory of the desired joint angle and angular velocity of the two-degree-of-freedom upper limb exoskeleton system and the switching controller into the state space expression to obtain the angle, angular velocity, angle error, and angular velocity error of the wrist joint of the upper limb exoskeleton system at different times. The preset performance of the upper limb exoskeleton system is controlled by the angle, angular velocity, angle error, and angular velocity error of the wrist joint of the upper limb exoskeleton system at different times.

[0053] The stability and convergence of the sliding mode controller designed in step 3 are proved by the Lyapunov comprehensive energy function method; and it is proved that the controller designed based on the control barrier function can make the 0-superlevel set a forward invariant set.

[0054] Step 5: Verify the effectiveness of the control strategy through MATLAB / Simulink model.

[0055] The dynamic model of the two-degree-of-freedom upper limb exoskeleton system described in step 1 is:

[0056]

[0057] where θ = [θ1, θ2] T is the exoskeleton joint angle vector, and θ1 and θ2 are the angles of the wrist internal and external rotation joints and wrist flexion-extension joints, respectively; and Represent the joint angular velocity and angular acceleration vector of the upper limb exoskeleton respectively; M(θ)∈R 2×2 is a positive definite symmetric inertia matrix; is the centrifugal force and Coriolis force matrix; G(θ)∈R 2×1 represents the gravity vector; τ=[τ1,τ2] Trepresents the control torque vector, and τ1 and τ2 represent the upper limb exoskeleton wrist joint actuator control torque, τ ex Represents the external lumped disturbance vector of the exoskeleton system.

[0058] Let x = [x1, x2] T , where x1 = θ, According to the dynamic model of formula (1), the state space expression is:

[0059]

[0060] Where, Control input u=M -1 (x1)τ, external aggregate interference d = -M -1 (x1)τ ex For the convenience of expression, f=-M -1 (x1)[C(x1,x2)x2+G(x1)].

[0061] The reference trajectory of the desired joint angle and angular velocity of the two-DOF upper limb exoskeleton is: d =[θ d1 ,θ d2 ] T ,

[0062]

[0063] Among them, θ d1 and θ d2 They are the expected trajectories of the wrist internal and external rotation joints and the wrist flexion and extension joint angles; and They are the expected angular velocity trajectories of the wrist internal and external rotation joints and the wrist flexion and extension joints. According to the angle tracking error e1 = x1-x d and angular velocity tracking error And considering the exponentially decreasing performance function, it can be expressed as:

[0064]

[0065] where p1(t) and p2(t) are predefined smooth performance functions that specify the desired transient and steady-state performance, which can be uniformly expressed as:

[0066]

[0067] Among them, p i,0 >p i,∞ >0,α i Used to adjust the decay rate of the performance function.

[0068] The sliding mode controller design process is as follows: Design the sliding surface based on the trajectory tracking error:

[0069] s=c1e1+e2; (6)

[0070] Where c1>0, take the derivative of both sides of (6) and substitute equation (2) into it to obtain:

[0071]

[0072] Robust tracking controller τ based on the idea of ​​sliding mode control algorithm r The design is as follows:

[0073]

[0074] In the formula, c1, η are constants greater than zero, e2 is the angular velocity tracking error, and are the expected angular velocity trajectories of the wrist internal and external rotation joints and the wrist flexion and extension joints, D is the upper bound of the external disturbance, s is the sliding surface, and f = -M -1 (x1)[C(x1,x2)x2+G(x1)], x1=θ,

[0075] The control block diagram of the sliding mode control strategy of the upper limb exoskeleton system based on the control obstacle function is as follows: Figure 2 As shown in the flowchart of steps Figure 3 shown.

[0076] The specific process of proving the stability and convergence of the designed sliding mode controller through the Lyapunov energy function is as follows:

[0077] Considering the designed sliding surface, the energy Lyapunov function is constructed:

[0078]

[0079] After taking the derivative of V, we get:

[0080]

[0081] Substituting the sliding mode controller (8) without constraints within the boundary into the equation, we obtain:

[0082]

[0083] Where sign(s) is the sign function.

[0084] Since D is the upper bound of external interference, we can further get This shows that over time the system state will gradually converge to the sliding surface (s=0) and eventually remain at zero. According to the Hurwitz property of the sliding surface, it can be seen that the trajectory tracking errors e1 and e2 converge asymptotically to zero.

[0085] The specific design process of the control barrier function is as follows: Considering the continuous differentiable function h(x), the present invention defines the following set:

[0086]

[0087] in, represents the boundary of the safe set, and Int(C) represents the interior of the safe set. If there exists a controller with Lipschitz conditions such that the set C is a forward invariant set, then the system can guarantee the constraints specified by C.

[0088] Preset performance control is a cutting-edge control method in the field of control. It constrains the limited state within a designable boundary by means of state space transformation. In this paper, the preset performance control method is used to constrain the dynamic and steady-state performance of the tracking error so that the tracking error does not exceed the predetermined boundary function during the convergence process, as shown in Equation (13). In order to achieve the desired tracking constraint in (4), the following two continuously differentiable functions are defined:

[0089]

[0090] In addition, in order to achieve the forward invariance condition of the control barrier function, the following auxiliary states are defined:

[0091]

[0092] Wherein, l1 and l2 are positive constants to be designed. Based on this, the present invention further defines the following super level set:

[0093]

[0094] Combine conditions (13) and (14) with the following conditions:

[0095]

[0096] Among them, l1>0, l2>0.

[0097] In order to achieve accurate angle tracking, the baseline sliding mode controller τ is modified r (t) A quadratic programming performance control strategy is proposed:

[0098]

[0099] in,

[0100]

[0101] Among them, if there exists u such that C1 and C2 hold, then h1(x) and h2(x) are called control barrier functions, and D is the upper bound of external interference.

[0102] We further use the Karush Kuhn-Tucker condition to solve the explicit form in (17) and consider the following Lagrangian function:

[0103]

[0104] Where λ1 and λ2 are both Lagrange multipliers. According to whether the two performance functions in (17) are valid, the optimized controller can be solved as follows:

[0105]

[0106] in, i is the dimension of e1, sign(s) is the sign function, and R represents the real number space. Here R 2 It refers to the entire two-dimensional space and is a commonly used expression in mathematics. χ0, χ1, and χ2 are the defined sets of regions and are commonly used expressions in mathematics.

[0107] The following method proves that the designed Lipschitz controller based on the control barrier function can make the 0-superlevel set always a forward invariant set:

[0108] According to assumption (16) and if h1(0,e1(0)), h2(0,e1(0)), If ψ1(t,e1(0),e2(0)) are all positive, then (17) can be rewritten as the following two inequalities:

[0109]

[0110] It can be seen that if the previous assumptions and initial conditions are met, the controller u is a non-empty set. And according to (16) we can get

[0111]

[0112] Equation (14) can be further rewritten as:

[0113]

[0114] because The initial values ​​of and ψ1 are both positive, and (14) can ensure that Q 1,1 and Q 1,2It is a forward invariant set. The same analysis shows that when h1(0,e1(0))≥0 and h2(0,e1(0))≥0, the set Q 1,0 and Q 2,0 is also a forward invariant set. Therefore, the set The forward invariance property of is guaranteed, thus satisfying the specified performance constraints.

[0115] The MATLAB / Simulink model in step 5 consists of the system input part (3), the sliding mode controller part (20) based on the control obstacle function, and the controlled object part (2). The input part (3) and (20) are input into the controlled object formula. The controlled object formula is updated over time and outputs four parameters: the joint angle, angular velocity, angle error, and angular velocity error of each joint of the two-degree-of-freedom upper limb exoskeleton system.

[0116] The specific process of verifying the effectiveness of the proposed control strategy using the MATLAB / Simulink model is as follows: First, set the simulation parameters, and the initial system joint angle is set to x1(0) = [1.5, 2] T (rad), the angular velocity of each joint is set to x2(0)=[0,0] T (rad / s), the system disturbance is set to d = [10sin(0.5t), 10sin(0.5t)] T (rad / s). The gain c1 in equation (8) is 20, the parameter η is 50, and the constraint boundary in equation (13) is set to p1(t) = 0.4πe -6t +0.1, p2(t)=0.4πe -6t +0.1. In formula (18), the upper bound of external interference D = [50,50] T (rad / s), parameters l1=2000, l2=50. The simulation time is set to 5s. A sudden interference is added between [3,3.1]s as d e =255(rad / s).

[0117] The simulation results of the tracking control effect of the sliding mode control method of the upper limb exoskeleton system of the present invention are as follows: Figure 4-9 As shown. Figure 4 (a) and Figure 4 From (b), we can see that the proposed control scheme can track the desired trajectory in about 0.3s, and can also track the desired trajectory over time in the case of sudden interference. Figure 5 (a) and (b) of 5 show that the angle steady-state tracking error of wrist internal rotation and external rotation joint and wrist flexion and extension joint finally converges to 10 -4 (rad) range, and the angular velocity steady-state tracking error converges to 10 -2(rad / s) range. Figure 6 The simulation results of (a) show that the controller designed by the present invention can make the 0-super level set that satisfies the control barrier function into a forward invariant set, and it can be seen from the local enlarged diagram that it will not be less than zero in the case of sudden interference. Figure 6 (b) is the simulation result diagram of the error norm constraint. From the local magnified diagram, it can be clearly seen that sudden interference will not cause the state to escape from the safe set, which ensures the security of the system. Figure 7 (a) and (b) show the simulation results of two joint angle error constraints respectively. It can be seen that the proposed scheme can make the state constraints within the safe set in the case of sudden interference. Figure 8 The simulation results of the control input show that when the system is in steady state, the controller input is around 0.05 (n / m). Figure 9 The simulation results of the angle error and angular velocity error changing with time in the phase plane are shown. It can be seen from the figure that the state will gradually converge to a tight set near zero over time, which illustrates the effectiveness and stability of the proposed scheme.

[0118] The present invention also provides an upper limb exoskeleton system preset performance control system, comprising:

[0119] A state space expression acquisition module is used to obtain the angle and control torque of the wrist joint of the two-degree-of-freedom upper limb exoskeleton system, establish a dynamic model of the two-degree-of-freedom upper limb exoskeleton system based on the angle and control torque of the wrist joint, and construct a state space expression based on the dynamic model;

[0120] A control obstacle function construction module is used to set the constraint boundaries of the wrist joint angle at different times and construct a control obstacle function based on the constraint boundaries;

[0121] a sliding mode controller design module for obtaining a reference trajectory of desired joint angles and angular velocities for a two-degree-of-freedom upper limb exoskeleton system, designing a sliding mode surface based on tracking errors of the reference trajectory of desired joint angles and angular velocities, and designing a switching controller based on the sliding mode surface and a control obstacle function;

[0122] The control module is used to input the reference trajectory of the desired joint angle and angular velocity of the two-degree-of-freedom upper limb exoskeleton system and the switching controller into the state space expression, obtain the angle, angular velocity, angle error, and angular velocity error of the wrist joint of the upper limb exoskeleton system at different times, and control the preset performance of the upper limb exoskeleton system through the angle, angular velocity, angle error, and angular velocity error of the wrist joint of the upper limb exoskeleton system at different times.

[0123] The present invention also provides a computer device comprising a memory and a processor; the memory stores a computer program, and the processor is used to run the computer program in the memory to execute a preset performance control method for an upper limb exoskeleton system.

[0124] The present invention also provides a computer-readable storage medium storing a computer program, wherein the computer program is suitable for loading by a processor to execute a preset performance control method for an upper limb exoskeleton system.

[0125] The above-described embodiments are only preferred specific implementation methods of the present invention, and the protection scope of the present invention is not limited thereto. Any simple changes or equivalent replacements of the technical solutions that can be obviously obtained by any technician familiar with the field within the technical scope disclosed in the present invention fall within the protection scope of the present invention.

Claims

1. A method for controlling preset performance of an upper limb exoskeleton system, characterized in that: The steps include: Obtain the angle and control torque of the wrist joint of the two-degree-of-freedom upper limb exoskeleton system, establish a dynamic model of the two-degree-of-freedom upper limb exoskeleton system based on the angle and control torque of the wrist joint, and construct a state space expression based on the dynamic model; Based on the dynamic model, setting constraint boundaries of the wrist joint angle at different times, and constructing a control obstacle function according to the constraint boundaries; Obtaining reference trajectories of desired joint angles and angular velocities of a two-degree-of-freedom upper limb exoskeleton system, designing a sliding surface based on tracking errors of the reference trajectories of desired joint angles and angular velocities, and designing a synovial controller based on the sliding surface and a control obstacle function; The reference trajectory of the desired joint angle and angular velocity of the two-degree-of-freedom upper limb exoskeleton system and the synovial controller are input into the state space expression to obtain the angle, angular velocity, angle error and angular velocity error of the wrist joint of the upper limb exoskeleton system at different times. The preset performance of the upper limb exoskeleton system is controlled by the angle, angular velocity, angle error and angular velocity error of the wrist joint of the upper limb exoskeleton system at different times.

2. The upper limb exoskeleton system preset performance control method according to claim 1, characterized in that: The wrist joints include wrist internal and external rotation joints and wrist flexion and extension joints.

3. The upper limb exoskeleton system preset performance control method according to claim 2, characterized in that: The kinetic model is as follows: where θ = [θ1, θ2] T is the exoskeleton joint angle vector, and θ1 and θ2 are the angles of the wrist internal and external rotation joints and wrist flexion-extension joints, respectively; and Represent the joint angular velocity and angular acceleration vector of the upper limb exoskeleton respectively; M(θ)∈R 2 ×2 is a positive definite symmetric inertia matrix; is the centrifugal force and Coriolis force matrix; G(θ)∈R 2×1 represents the gravity vector; τ=[τ1,τ2] T represents the control torque vector, τ1 and τ2 represent the control torques of the wrist internal and external rotation joints and wrist flexion and extension joint actuators of the upper limb exoskeleton, respectively; τ ex Represents the external lumped disturbance vector of the exoskeleton system.

4. The upper limb exoskeleton system preset performance control method according to claim 3, characterized in that: The state space expression is as follows: Where x1 = θ, u=M -1 (x1)τ is the control input, d=-M -1 (x1)τ ex is the external aggregate interference.

5. The upper limb exoskeleton system preset performance control method according to claim 4, characterized in that: The control barrier function is as follows: h1(t,e1)=||e1(t)||+p1(t), h2(t,e1)=p2(t)-||e1(t)||; Where e1(t) is the angle tracking error, and p1(t) and p2(t) are predefined smoothing performance functions.

6. The upper limb exoskeleton system preset performance control method according to claim 5, characterized in that: The sliding mode controller is as follows: Where c1,η is a constant greater than zero, e1 is the angle tracking error, e2 is the angular velocity tracking error, and are the expected angular velocity trajectories of the wrist internal and external rotation joints and the wrist flexion and extension joints, D is the upper bound of the external disturbance, s is the sliding surface, and f = -M -1 (x1)[C(x1,x2)x2+G(x1)], x1=θ, l1 and l2 are positive constants to be designed, h1 is the control obstacle function, p1 is the predefined smooth performance function, sign(s) is the sign function, and χ0, χ1, and χ2 are all defined region sets.

7. An upper limb exoskeleton system preset performance control system, characterized in that: include: A state space expression acquisition module is used to obtain the angle and control torque of the wrist joint of the two-degree-of-freedom upper limb exoskeleton system, establish a dynamic model of the two-degree-of-freedom upper limb exoskeleton system based on the angle and control torque of the wrist joint, and construct a state space expression based on the dynamic model; A control obstacle function construction module is used to set the constraint boundaries of the wrist joint angle at different times based on the dynamic model, and construct a control obstacle function according to the constraint boundaries; a sliding mode controller design module for obtaining a reference trajectory of desired joint angles and angular velocities of a two-degree-of-freedom upper limb exoskeleton system, designing a sliding mode surface based on a tracking error of the reference trajectory of desired joint angles and angular velocities, and designing a sliding mode controller based on the sliding mode surface and a control obstacle function; The control module is used to input the reference trajectory of the desired joint angle and angular velocity of the two-degree-of-freedom upper limb exoskeleton system and the synovial controller into the state space expression, obtain the angle, angular velocity, angle error and angular velocity error of the wrist joint of the upper limb exoskeleton system at different times, and control the preset performance of the upper limb exoskeleton system through the angle, angular velocity, angle error and angular velocity error of the wrist joint of the upper limb exoskeleton system at different times.

8. A computer device, characterized in that: It includes a memory and a processor; the memory stores a computer program, and the processor is used to run the computer program in the memory to execute the upper limb exoskeleton system preset performance control method according to any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, which is suitable for being loaded by a processor to execute the upper limb exoskeleton system preset performance control method according to any one of claims 1 to 6.

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