HIGH-ACCURACY DEFLECTION MEASUREMENT OF A PIEZOELECTRIC BEAM MULTILAYER ACTUATOR WITH AN INTEGRATED CAPACITIVE STRAIN SENSOR

摘要

To use piezoelectric bending actuators in various applications of automation systems the accurate control of the beam deflection is necessary. However the influence of hysteresis, nonlinearities, drift and external forces have to be compensated. We have developed a piezoelectric multilayer ceramic bender system with integrated capacitive strain sensor and high-accuracy electronic circuit. Using the information of the strain on the surface of the actuator beam we detect the bending deflection, independant of external forces, thus e.g. the control of the air flow in microvalves is possible. Significant results are: (1) An optimal sensor position on the actuator to detect deflection and external load; (2) The first measurements have shown the functionality of the integrated sensor in combination with a high-accuracy electronic.