Comparison of Calibration Techniques for Piezoelectric Force Sensors
摘要
There is a growing need for a simple, limited-equipment-required calibration method for piezoelectric force sensors. Deadweight or hydraulic techniques are commonly implemented in order to calibrate at multiple force levels over the sensor’s useable measurement range. With high measurement range force sensors, this requires a robust physical setup to safely apply the necessary load, as well as a data acquisition system able to support the piezoelectric sensor under test and the strain gage-based reference load cell. An alternative for small measurement range sensors is the simple-to-setup Gravimetric Drop calibration technique using gravity as a reference, requiring a single channel data acquisition system. However, this technique is limited by the amount of force that can be generated because only a small calibrated mass can be used. With this limitation, the high-range sensor may only be tested over a small percentage of its measurement range, making the technique unsuitable. A third option is to use an Impact Calibration technique similar to that of Modal Hammer Calibration. This technique offers a simple physical setup similar to that of calibrating a modal hammer using a two-channel data acquisition system needing to only support piezoelectric sensors while offering greater force level generation for the calibration of high-range force sensors similar to deadweight or hydraulic calibration systems. This paper compares the results of the Impact Calibration technique to the existing Gravimetric Drop Calibration and deadweight or hydraulic calibration methods.