A Symmetrical Hybrid Driving Waveform for a Linear Piezoelectric Stick-Slip Actuator

A symmetrical hybrid driving waveform (SHDW) is proposed in this paper, which includes a symmetrical saw-tooth driving waveform and a sinusoidal friction regulation waveform, and the sinusoidal friction regulation waveform is applied to the shrinkage period of the symmetrical saw-tooth driving waveform. In other words, the proposed SHDW can be achieved when the waveform symmetry of the hybrid driving method is 50%. The SHDW can effectively drive the designed symmetrical linear piezoelectric stick-slip actuator, and the motion direction is also easily regulated. The excitation principle of the actuator excited by the SHDW is explained in detail. A prototype is fabricated and the experimental investigations of the actuator characteristics are carried on. The higher velocity and the larger driving capacity are realized using by the SHDW relative to the asymmetrical hybrid driving waveform. Testing results show that the prototype excited by the SHDW can obtain the peak no-load speeds of 0.41 and 0.39 mm/s in the forward and reverse directions when the saw-tooth driving waveform voltage is 10 $\text{V}_{\text {p-p}}$ for 800 Hz and the sinusoidal friction regulation waveform voltage is 2 $\text{V}_{\text {p-p}}$ for 39 kHz. The step efficiencies can reach 92% and 90%. The driving capacities can reach 10.52 and 9.85 [(mm/s)g/mW] with the load of 70 g under the locking force of 0.1 N. The actuator excited by the SHDW will make it ideal for miniature information technology devices.