Design of an adaptive stator for bundled piezo-walk motors

Bundled piezoelectric motors combine several actuators to achieve high output power. However, mutual interference between the actuators leads to reduction in working efficiency. This work presents an adaptive stator that can reduce the mutual interference in bundled piezowalk motors. The stator consists of leaf springs for improving motor contact condition and proof masses that serve as an inertial body for maintaining high output force. Parameters of the proof masses and leaf springs are analyzed, and the working zone of the stator is discussed. A prototype of a linear motor with the designed adaptive stator is fabricated and tested. The maximum speed of a six-leg motor is 103 mm/s, and the stall force is approximately 1.2 N, driven with sinusoidal waveforms of 25V_pp at 30 kHz. Mutual interference between actuators is reduced remarkably with the adaptive stator. A comparison of six- and four-leg motors proves that motor performance has a linear relationship with the number of actuators, thereby indicating the potential of increasing output capability with additional actuators.