Position Control of Dielectric Elastomer Actuators Based on Port-Hamiltonian Framework

This paper deals with position control of an actuator system consisting of a dielectric elastomer membrane biased with a combination of a linear and a bi-stable spring. The highly nonlinear response of dielectric elastomer material, in conjunction with the bi-stable biasing spring, makes the control of the overall system challenging. To systematically address the design of the control system, a novel approach is proposed based on port-Hamiltonian (PH) theory. First, based on a recently developed PH model of the dielectric elastomer material, a PH model of the overall actuator system is obtained. Subsequently, several control laws are designed by means of PH theory, i.e., interconnection and damping assignment passivity-based control (IDA-PBC), and IDA-PBC with integral of non-passive output for robust regulation. The developed control laws are finally compared with a conventional PID, showing improved dynamic performance in the overall actuation range.