Analysis of geometrically nonlinear anisotropic membranes: application to pneumatic muscle actuators

Pneumatic muscle actuators are effective devices to generate tension forces by converting pneumatic energy into mechanical energy. They are currently being used in parachute systems for soft-landing and steering control applications. Therefore, the simulation of their nonlinear structural dynamic behavior is necessary for a complete evaluation of these parachute systems. In this paper, the working principles of pneumatic muscle actuators are reviewed; the application of pneumatic muscle actuators in parachute systems for soft-landing and steering control is described; and a new finite element model for pneumatic muscle actuators is presented. Geometrically nonlinear anisotropic membrane elements are used in this model to simulate the nonlinear structural dynamic behavior of pneumatic muscle actuators, which is different from previous approaches. A quasi-static pneumatic muscle actuator model is analyzed for validation and two dynamic applications of pneumatic muscle actuators in parachute systems are also presented.