Design of control system for rehabilitation use of pneumatic artificial muscles

Pneumatic artificial muscles (PAM) are actuators having many advantages such as high force to weight ratio, ease of maintenance, low cost, flexible structure. In addition, PAM is especially suitable for rehabilitation devices due to its operating character compliant to human muscle. On the other hand, pneumatic artificial muscles have major drawback that makes difficult to control due to their nonlinear properties. In this thesis, control systems have been analyzed and designed to solve the nonlinear control problem that restricts the use of pneumatic artificial muscle. Based on PID, Fuzzy PID and Sliding Mode Control methods, designs have been made according to the rehabilitation-oriented performance of the pneumatic artificial muscle. The main difference of this study from the literature is that control systems are designed for on/off valves which are more economical and allow the pneumatic artificial muscle to work in compliance, instead of the common proportional valves and pressure regulators. The designs have been experimentally evaluated on the pneumatic artificial muscles, which are included in the PAM control experimental setup and operated with on/off valves. According to the experimental results, the model-free Sugeno type combined fuzzy PID controller has yielded most successful performance as a simple and effective solution for the rehabilitation use of pneumatic artificial muscles (PAM).