Experimental implementation of a motion-compensated force control in a hydraulic workbench for flight actuators

The paper deals with the design and the experimental implementation of the force control in a hydraulic workbench for flight actuators, to be used for hardware-in-the-loop simulations of modern Fly-By-Wire Flight Control Systems. A basic problem affecting the plant performances is that the force response is sensitive to the flight actuator movements. Simulation results show that a suitable solution can be obtained including a compensation feedback based on the flight actuator acceleration, but sensor nonlinearities can induce relevant disturbances during experiments. In the paper, the model-inverting controller and the acceleration feedback are combined with a Kalman filter for compensating the accelerometer bias, and the performance of the closed-loop force-controlled plant is characterised by performing successive sessions of experiments, up to the simulation of the flight actuator dynamics during a typical flight manoeuvre.