Abstract
Pneumatic artificial muscles (PAMs) have many advantages for examples, a high power-to-weight ratio and a high degree of safety, in contrast to electric motors. However, their significant nonlinear characteristics limit their positioning accuracies. This paper describes a practical controller design for precision positioning of PAM systems and experimental results of the control system designed using the method. As the first step of this research, a linear motion mechanism with a pair of McKibben PAMs is constructed and its static and dynamic input-output characteristics are examined experimentally. Next, for precision positioning, the practical controller design procedure is discussed and determined based on the characteristics. The proposed controller design procedure can be easily implemented into PAM mechanisms without an exact dynamic model. The experimental results using the designed controller show that the positioning error is lower than 1 μm.
