基于高速开关阀的气动人工肌肉轨迹跟踪控制仿真

针对基于高速开关阀的气动人工肌肉位置伺服控制系统的非线性与时变性,设计了基于气动人工肌肉实验模型的PID反馈控制器,实现气动人工肌肉的高精度运动轨迹跟踪控制。首先,通过实验建模得到气动人工肌肉静态特性的实验模型,然后基于理想气体多变方程,建立可有效描述气动人工肌肉动态特性的数学模型,利用Sanville流量公式建立流经高速开关阀阀口的气体流量方程,并采用脉冲信号调制法生成PWM信号,进而控制高速开关阀占空比。在此基础上,借助PID反馈控制器建立气动人工肌肉气压与轨迹跟踪的控制模型,并采用Simulink对所提出的气压和轨迹跟踪控制方法进行数值仿真。结果表明,所建立的控制模型能够精确地跟踪期望气压和运动轨迹,从而验证了控制模型和控制方案的精确性和可行性,为实现气动人工肌肉高精度轨迹跟踪控制提供了有效手段。

Simulation of Tracking Control of Pneumatic Artificial Muscle Based on Fast Switching Valves

Due to the problem of nonlinear and time-varying exists in the model of the pneumatic artificial muscle (PAM) trajectory tracking control system, the modeling of the trajectory tracking control of PAM driven by fast switching valves was detailed in order to enhance the trajectory tracking control accuracy of PAM and reduce the cost of control scheme. A feedback PID controller based on the experimental model of PAM was proposed to achieve its high accuracy trajectory tracking control. The control system was divided into three subsystems, which were pneumatic artificial muscle, fast switching valve and the PWM signal. Firstly, the static model of PAM was established by the isometric experiment, and then the dynamic characteristic model of PAM was developed based on the polytropic equation, in which the air mass flow rate through the fast switching valve was evaluated by using the Sanville equation. The PWM signal that was used to control the fast switching valves was generated referring to the pulse signal modulation method. Sequentially, the pressure and trajectory tracking control models of PAM were derived by means of feedback PID controller, based on which the simulations of pressure and trajectory tracking control were implemented in the environment of Matlab/Simulink. The results indicated that the control model can achieve satisfactory performance and accuracy, which validated the feasibility of the proposed model and control scheme. Thus, it provided an effective approach for high accuracy trajectory tracking control of PAM.