Modeling and experimental evaluation of the stepping characteristic on a walking-type piezoelectric actuator

Aiming at the suppression of backward motion, a walking-type piezoelectric actuator was developed in this paper. Two walking modes of ellipse-shaped walking and rhombus-shaped walking were discussed. The dynamic models in the x and y direction were established to simulate the stepping characteristics of two walking modes. The simulated results depicted that the actuator was able to achieve stepping displacement free of backward motion. A prototype was fabricated, and a series of experiments were conducted. The experiments indicated that, under two walking modes, there was a backward displacement in each operating cycle due to assembly errors. To suppress backward motion, a solution to compensate for the assembly errors by varying the bias voltage difference between two stators was proposed. After correcting the assembly errors, the backward displacements were almost eliminated and reduced by 71.4% from 0.28 to 0.08 μ m and 68.1% from 0.22 to 0.07 μ m, respectively under the ellipse-shaped walking mode and rhombus-shaped walking mode, which proved the effectiveness of the proposed actuator.