Motion type analysis of a piezoelectric-actuated vibratory micro-robot in hybrid stick-slip-jump mode

In this paper, the stick-slip-jump motion of a micro-robot with two perpendicular vibratory actuators is studied. A practical model of this micro-robot is designed and fabricated with two Langevin type piezoelectric actuators, which are driven by harmonic voltages. Depending on the amplitude and frequency of the driving voltages of the micro-robot actuators, as well as their phase difference, the type of the motion dynamics and the states of the contact points in the motion (slipping or jumping) are determined. Considering the conditions of the contact points of the micro-robot, the motion is based on the combination of the friction drive principle (stick-slip) and jumping phenomenon. A finite element model of the micro-robot is used to investigate the motion type of the micro-robot in the stick-slip-jump mode. Because there exist various states of motions in the stick-slip-jump mode, the exact analytical study is very complicated. Therefore, in this study, the type of motion (stick-slip-jump) and the condition for the start of the movement have been investigated and determined by the FEM (Finite Element Method) analysis.