膝-踝-趾动力型假肢解耦控制研究

Decoupling control of knee-ankle-toe active transfemoral prosthesis

针对膝-踝-趾动力型假肢系统的强耦合性,导致系统控制效果不理想等问题,本文设计控制法则分解法解耦器对系统进行解耦,降低耦合度,提高控制效果。利用拉格朗日方程建立了膝-踝-趾动力型假肢系统支撑末期的动力学模型,此模型的耦合度为1.22,耦合性较强,需要进行解耦;基于控制法则分解法设计模型解耦器,以此简化假肢系统,将耦合度强的系统简化为膝、踝、趾独立控制的模型;基于自适应迭代学习设计控制器,对解耦前后三自由度假肢系统的各关节进行控制。结果表明:此解耦器可以将假肢模型简化为3个单输入、单输出的系统,同时降低关节间的耦合度,加快系统的收敛速度,与解耦前的控制效果相比,解耦后系统收敛误差明显减小。本文为多关节假肢系统提供了模型简化方法,为实物样机控制提供理论验证。

As the knee-ankle-toe dynamic prosthesis system has strong coupling,the control effect of this system is not ideal.A decoupler of the control law decomposition method is proposed to reduce the coupling degree and im-prove the control effect.First,the dynamics model of the knee-ankle-toe transfemoral prosthesis system is estab-lished using the Lagrange equation.This model has strong coupling,with a coupling degree of 1.22 and needs de-coupling.Therefore,a model decoupler is designed using the control law decomposition method to simplify the prosthesis system,transforming a strong coupling system to independent control models of knee,ankle,and toe.Finally,based on adaptive iterative learning,a controller is designed to control the joints of the 3-DOF prosthesis system before and after decoupling.The results reveal that the decoupler can simplify the prosthesis model into three single-input and single-output systems,which simultaneously reduce the coupling between joints and acceler-ate the convergence rate of the system.Compared with the control effect before decoupling,the convergence error of the system is obviously reduced after decoupling,providing a method for simplifying the model for a multi-joint prosthesis system and theoretical verification for physically controlling the prototype control.