Active bearing preload control of a high speed spindle using piezoelectric actuators

This paper will report an active bearing-preload control mechanism using piezoelectric actuators. In order to overcome the problems of nonlinearity, hysteresis and DC drift of the piezo-actuator, a strain gage load cell is integrated into the piezoelectric actuators. Bearing preload is monitored on line by the load cell and then fed back to the piezoactuator. Results of the experiments conducted on a bearing testing stand are also reported. Test results show that the piezo-actuator can control the bearing preload well. The advantages of piezoelectric actuators are compact size, easy control, and precise motion. It can be easily implemented into a spindle without the increasing of the spindle size.