Motion Analysis of a Vibrational Microrobot With Two Perpendicular Harmonic Actuators and Deriving the Design Parameters in Stick-Slip Mode

In this paper, the stick-slip motion of a microrobot with two perpendicular vibrational actuators is studied. This motion is based on the friction drive principle. To determine the effective parameters in the motion of microrobot, the equations of motion of the microrobot are derived. To simplify the equations for determining the design parameters, the vibrational actuators are modeled with two perpendicular harmonic forces. To study the motion dynamics of the microrobot, its equation of motion is derived in a nondimensional expression by defining the nondimensional effective parameters. The Fourier expansion (F.E.) method is used to analyze the numerical results and it showed some differences between the obtained results and the studies performed by the harmonic balance (H.B.) method. The discussion about motion characteristics of microrobot is done by defining the mean velocity and performance coefficient of the stick-slip motion. Finally, a practical model of this microrobot is designed and fabricated with two piezo-electric actuators, and then, the motion capability of the microrobot is verified by test.