A walking type piezoelectric actuator based on the parasitic motion of obliquely assembled PZT stacks

In order to decrease the backward motion and improve the motion efficiency, a walking type piezoelectric actuator has been proposed with two 'legs' based on the parasitic motion of obliquely assembled PZT stacks. The structure and motion principle of the proposed walking type piezoelectric actuator are described, and its experiment system is set up. Experimental results indicate the proposed piezoelectric actuator could reduce the backward motion effectively. The minimum backward rate α= 2.26% is achieved under the condition of the phase difference θ= 180°, the input voltage U= 120 V and the input frequency f= 1 Hz; the minimum stepping displacement is 0.24 μm under the condition of U= 5 V, f= 1 Hz and θ= 180°; the maximum speed Vmax is 2472 μm s−1 under the condition of U =120 V and θ= 180°; the maximum vertical load force FVmax = 6850 g under the condition of U = 120 V, f = 1 Hz and θ = 180°. Furthermore, a dynamic model of the whole walking type piezoelectric actuator is established, and it has been employed to simulate the motion of the proposed walking type piezoelectric actuator. Simulation results present a great agreement of experimental results. This study shows a novel idea for the design of piezoelectric actuators to eliminate the influence of backward motion and improve the output efficiency of the actuator.