Position/Force Control of a 1-DoF Set-up Powered by Pneumatic Muscles

A one-degree-of-freedom set-up driven by pneumatic muscles was designed and built in order to research the applicability of pneumatic artificial muscles in industrial applications, especially in wearable robots such as exoskeletons. The experimental set-up is very non-linear and very difficult to control properly. This paper describes the control of this mechatronic system’s interaction with its environment, controlling both its position and the force exerted against it by the implementation of bioinspired algorithms. Specifically, two different variations of the Compliance Control have been adapted for their application in the experimental device powered by pneumatic muscles. It is worthy of mention that an estimator has been developed in order to close the inner torque and pressure loops without the use of any torque or force sensor. Finally, the article concludes by presenting the experimental results obtained and the most outstanding conclusions of the study as a whole.