Actuator design using biomimicry methods and a pneumatic muscle system

An empirical and theoretical study is conducted on a special actuator termed “pneumatic muscle” (PM) being used in a force control system framework. Such an actuator has similarities to biological systems and has many advantages (extremely high power/weight, power/volume and power/energy ratios). However, due to its inherent nonlinearities, this actuator suffers from poor position and force control. The study described here accomplishes three main goals. (1) A force control system is developed within an open and closed loop framework to emulate how biological systems work in an agonist–antagonist framework. (2) The PM used in the study has such strength that it excites the frame dynamics. This undesired dynamic response is then effectively cancelled using an impedance model control scheme. (3) The PM is demonstrated to both change length yet still produce force in a controlled manner.