Position and force self-sensing piezoelectric valve with hysteresis compensation

This paper presents an approach for self-sensing piezoelectric valves. Both displacement and actuation force of piezoelectric valve can be simultaneously estimated from measurements of the charge and driving voltage. Only simple calibration is required before engineering application. The charge is obtained by software integration of the piezoelectric current sampled by DAQ card, which has the advantage of compensating leakage current by pre-estimating the leakage resistance. A PID controller is used to track the displacement, and a feedfoward compensation using Prandtl-Ishlinskii model is taken to compensate the piezoelectric hysteresis. The experimental results show that the controller can track target displacement within 2.03% of error, track force within 1.80% of error, and the maximum hysteresis of actuator is compensated from 27% to 3.75%.