Ariable stiffness exoskeleton simulation method, system, and computer program product

Abstract

This disclosure provides a simulation method for a variable stiffness exoskeleton, executed by a processor. The simulation method includes: (a) receiving multiple user joint motion parameters and dynamic load information input by a model input module; (b) establishing a mathematical simulation model of the variable stiffness mechanism using a variable stiffness mechanism modeling module based on the information, and analyzing the deformation state of the bending or flexible components of the variable stiffness mechanism; (c) simulating and predicting the output torque and energy consumption of the variable stiffness mechanism after deformation using an energy conversion efficiency simulation module based on the mathematical simulation model; and (d) generating optimized control parameters for driving the actuators of the exoskeleton based on the simulated output torque and energy consumption using a control parameter generation module.

Claims

1. A simulation method for a variable stiffness exoskeleton, executed by a processor, comprising the following steps: Step (a): receiving a plurality of user joint motion parameters and dynamic load information input by a model input module; Step (b): based on the information, establishing a mathematical simulation model of a variable stiffness mechanism through a variable stiffness mechanism modeling module, and analyzing the deformation state of a bending member or a flexible element of the variable stiffness mechanism; Step (c): based on the mathematical simulation model, simulating and predicting an output torque and an energy consumption of the variable stiffness mechanism after the deformation state through an energy conversion efficiency simulation module; and Step (d): based on the simulated output torque and energy consumption, generating a set of optimized control parameters through a control parameter generation module for driving a actuator of the exoskeleton.

2. A simulation method for a variable stiffness exoskeleton as described in claim 1, wherein, Step (c) further includes a feasibility verification step, in which the energy conversion efficiency simulation module determines whether the output torque is stable and whether the energy consumption is lower than a preset threshold. If the determination result is negative, it is fed back to step (b), whereby the variable stiffness mechanism modeling module adjusts a geometric parameter or a boundary condition of the variable stiffness mechanism in the mathematical simulation model, and the simulation of step (c) is repeated until the determination result is positive.

3. A simulation method for a variable stiffness exoskeleton as described in claim 1, wherein, In step (b), the variable stiffness mechanism modeling module establishes the mathematical simulation model based on a virtual work principle; wherein, the variable stiffness mechanism includes a cam mechanism, the deformation path of the bending member or the flexible element is defined by a profile curve of the cam mechanism, the profile curve is determined by a plurality of control points, and the variable stiffness mechanism modeling module analyzes the deformation state by adjusting the position of these control points.

4. A simulation method for a variable stiffness exoskeleton as described in claim 1, wherein, Step (b) further includes outputting a design specification corresponding to the variable stiffness mechanism, the design specification including at least one of the geometrical parameters of the bending element or the flexible element, the material mechanical properties, and the cam profile curve data; the geometrical parameters including at least a width and a height, and the material mechanical properties including at least a Young's coefficient and a yield strength.

5. A simulation method for a variable stiffness exoskeleton as described in claim 1, wherein, In step (c), the energy conversion efficiency simulation module performs a finite element analysis on the mathematical simulation model to generate a stress distribution cloud map. The energy conversion efficiency simulation module compares a maximum stress value in the stress distribution cloud map with a material yield strength, and compares a simulated stiffness characteristic curve with a design target, as a basis for verifying whether the variable stiffness mechanism is qualified.

6. A simulation method for a variable stiffness exoskeleton as described in claim 1, wherein, The exoskeleton includes the actuator, the variable stiffness mechanism, and an exoskeleton link; the actuator is a motor, the variable stiffness mechanism includes a cam and at least one flexible member, the motor is configured to drive the cam to rotate, thereby changing one of the preloads or a bending path of the flexible member, thereby adjusting one of the equivalent stiffnesses of the variable stiffness mechanism; the exoskeleton link is coupled to the variable stiffness mechanism.

7. A simulation method for a variable stiffness exoskeleton as described in claim 5, wherein, The exoskeleton is a modular configuration selected from the following groups or combinations thereof: a hip joint module, a right knee joint module, and a left knee joint module; the variable stiffness mechanism modeling module establishes the corresponding mathematical simulation model based on the design objectives and task parameters corresponding to the selected modular configuration.

8. A simulation method for a variable stiffness exoskeleton as described in claim 1, wherein, The optimized control parameters generated in step (d) form a mathematical lookup table or a function model. The optimized control parameters define the mapping relationship between the joint motion parameters and a drive signal of the actuator, which includes a current value or a duty cycle.

9. A simulation system for a variable stiffness exoskeleton, comprising: a model input module for receiving a plurality of user joint motion parameters and dynamic load information; a variable stiffness mechanism modeling module coupled to the model input module for establishing a mathematical simulation model of a variable stiffness mechanism based on the information, and analyzing the deformation state of a bending member or a flexible element of the variable stiffness mechanism; an energy conversion efficiency simulation module coupled to the variable stiffness mechanism modeling module for simulating and predicting an output torque and an energy consumption of the variable stiffness mechanism after deformation based on the mathematical simulation model; and a control parameter generation module coupled to the energy conversion efficiency simulation module for generating a set of optimized control parameters based on the simulated output torque and energy consumption to drive an actuator of the exoskeleton.

10. A program product comprising instructions that, when executed by a processor, cause the processor to perform a simulation method for a variable stiffness exoskeleton, the method comprising the following steps: step (a): receiving a plurality of user joint motion parameters and dynamic load information; step (b): based on the information, establishing a mathematical simulation model of a variable stiffness mechanism and analyzing a deformation state of a bending member or a flexible element of the variable stiffness mechanism; step (c): based on the mathematical simulation model, simulating and predicting an output torque and an energy consumption of the variable stiffness mechanism after the deformation state; and step (d): based on the simulated output torque and energy consumption, generating a set of optimized control parameters for driving an actuator of the exoskeleton.

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