An approach to multibody simulation of pneumo-mechanical systems

This work describes a method for the simulation of multiple pneumatic actuators in a context of multi body mechanical systems. The model of the single actuator is based on elliptical approximation of non-linear pneumatic devices; friction and sticking phenomena are considered as well. Pneumatic devices introduce forces and new state variables into the complete multibody system: we developed a scheme which minimizes the computational effort for the integration process. After many comparisons with data coming from an experimental device, results provided by our simulation engine proved to be reliable and easy to use. Finally, as an example of a complex multibody device with pneumatic actuators, we present the model of a 3DOF parallel robot whose motion is achieved by means of three pneumatic cylinders, each controlled by a 5-3 proportional valve.