Automatic tuning of pneumatic servo actuators

The high power-to-weight ratio and low cost of pneumatic actuators makes them attractive for robotics and automation applications; however, achieving fast, accurate position control with them is difficult. Furthermore, tuning the controller (and/or obtaining process models) requires extensive expertise and time. In this paper, a novel automatic tuning methodology for the accurate position control of pneumatic servo actuators is described. The methodology combines off-line model-based analysis with on-line iteration. Experiments performed on three actuators with distinct open-loop dynamics verified the auto-tuner's effectiveness. The auto-tuning required 1/50 of the time needed for manual tuning and only non-expert supervision. The performance of the auto-tuned actuators is comparable to that achieved by other researchers using more complex and expensive hardware.