This paper proposes a method that combines LQG control design and structure preserving model reduction for the reduced order control of Infinite Dimensional Port Hamiltonian Systems (IDPHS). For that purpose the weighting operators used in LQG control design are chosen such that the resulting dynamic controller is passive and the closed-loop system equivalent to control by interconnection. The method of Petrov-Galerkin is then used to approximate the balanced realization of the IDPHS by a finite dimensional port Hamiltonian system and to provide the associated reduced order LQG controller. The main advantages of the proposed method are that, first, both control and reduction are driven by closed-loop performances and that, second, due to the passivity properties of the controller the closed-loop stability is guaranteed when the finite dimensional controller is applied to the infinite dimensional system.

This paper deals with the modeling and control problem of a Hydraulically Amplified Self-healing Electrostatic (HASEL) actuator based on the port-Hamiltonian framework. A nonlinear spring-damper system is used to approximate the mechanical deformation of the actuator due to the motion of the fluid while a nonlinear capacitance is used to approximate the electric behavior of the system. The actuator position control strategy is investigated based on the Interconnection Damping Assignment-Passivity Based Control (IDA-PBC) method, with further Integral Actions (IA) added to cope with load uncertainties. The proposed model and control laws are validated on an experimental benchmark. The experimental tests demonstrate that the proposed model is accurate up to 94% of fitness. The controllers allow assigning the actuator position with ramp and sinusoidal references with the relative error less than 5%. At last, the robustness of the proposed IDA-PBC controller with IA has been shown with the experimental result for the unknown load disturbance rejection.