Veltink P H, Chizeck H J, Crago P E, el-Bialy A
Department of Electrical Engineering, University of Twente, Enschede, The Netherlands.
IEEE Trans Biomed Eng. 1992 Apr;39(4):368-80. doi: 10.1109/10.126609.
Designs of both open- and closed-loop controllers of electrically stimulated muscle that explicitly depend on a nonlinear mathematical model of muscle input-output properties are presented and evaluated. The muscle model consists of three factors: a muscle activation dynamics factor, an angle-torque relationship factor, and an angular velocity torque relationship factor. These factors are multiplied to relate output torque to input stimulation and joint angle. An experimental method for the determination of the parameters of this model was designed, implemented, and evaluated. An open-loop nonlinear compensator, based upon this model, was tested in an animal model. Its performance in the control of joint angle in the presence of a known load was compared with a PID controller, and with a combination of the PID controller and the nonlinear compensator. The performance of the nonlinear compensator appeared to be strongly dependent on modeling errors. Its performance was roughly equivalent to that of the PID controller alone: somewhat better when the model was accurate, and somewhat worse when it was inaccurate. Combining the nonlinear open loop compensator with the PID feedback controller improved performance when the model was accurate.
本文提出并评估了明确依赖于肌肉输入-输出特性非线性数学模型的电刺激肌肉开环和闭环控制器设计。肌肉模型由三个因素组成：肌肉激活动力学因素、角度-扭矩关系因素和角速度-扭矩关系因素。这些因素相乘，以将输出扭矩与输入刺激和关节角度相关联。设计、实施并评估了一种用于确定该模型参数的实验方法。基于该模型的开环非线性补偿器在动物模型中进行了测试。将其在已知负载下控制关节角度的性能与PID控制器以及PID控制器与非线性补偿器的组合进行了比较。非线性补偿器的性能似乎强烈依赖于建模误差。其性能大致等同于单独的PID控制器：模型准确时性能稍好，模型不准确时性能稍差。当模型准确时，将非线性开环补偿器与PID反馈控制器相结合可提高性能。
