A Low-Cost Force Sensor for Electromechanical Actuation Systems

In this paper, a new method to interface with a piezoelectric sensor for quasi-static force measurement is proposed. Using the so-called digital charge amplifier (DCA), the output signal from the sensor is sampled and integrated using digital techniques that include a drift compensation algorithm. The algorithm continually monitors the sensor output and estimates bias errors that will cause the output to drift. Analytical and simulation results are used to show that the DCA yields a sensor response that is free of drift and has a better low frequency response compared to drift-free analog techniques. Hardware results are used to validate the practicality of the approach.