Nonlinear observer-based optimal control of an active transfemoral prosthesis

Abstract

This paper designs a joint controller/observer framework using a state dependent Riccati equation (SDRE) approach for an active transfemoral prosthesis system. An integral state control technique is utilized to design a tracking controller for a robot/prosthesis system. This framework promises a systematic flexible design using which multiple design specifications such as robustness, state estimation, and control optimality are achieved without the need for model linearization. Performance of the proposed approach is demonstrated through simulation studies, which show improvements versus a robust adaptive impedance controller and an extended Kalman filter-based state estimation method. Numerical results confirm the benefits of our method over the above-mentioned approaches with regard to control optimality and state estimation. 摘要本文使用状态依赖的Riccati 方程(SDRE)方法为主动经股假体系统设计联合控制器/观察器框架。 利用积分状态控制技术来设计机器人/假体系统的跟踪控制器。该框架保证了系统灵活设计, 通过该设 计, 可以实现多种设计参数优化, 例如鲁棒性、状态估计和控制最佳性, 而无需模型线性化。仿真研 究证明了该方法的性能, 较鲁棒的自适应阻抗控制器和基于扩展卡尔曼滤波器的状态估计方法有所改 进。数值结果证实了本方法在控制最优性和状态估计方面优于上述方法。