Pressure Control with On-Off Valves of Pleated Pneumatic Artificial Muscles in a Modular One-Dimensional Rotational Joint

The power to weight ratio of the actuators is an important design factor for running robots. In this regard pleated pneumatic artificial muscles are excellent actuators. Another advantage is that they can actuate a joint directly, avoiding the additional weight of a gearbox. Obviously the weight of the pressure control valves has to be taken into consideration as well. For this application, standard pressure regulating valves are rather heavy and slow. An intelligently controlled array of fast switching on-off valves was tested as an alternative. Ways to decrease the opening and closing times of these valves are discussed in this paper. Simulations and experimental results will be compared. The design of a modular rotational joint with an antagonistic set-up of two pleated pneumatic artificial muscles will be presented.