Development of 3-DOF Inchworm Mechanism for Flexible, Compact, Low-Inertia, and Omnidirectional Precise Positioning: Dynamical Analysis and Improvement of the Maximum Velocity Within No Slip of Electromagnets

In this paper, we describe the dynamical analysis and improvement of the maximum velocity within no slip of electromagnets for a 3-DOF inchworm mobile mechanism. The mechanism consists of four “Moonie” piezoelectric actuators and a pair of electromagnets and moves like an inchworm with less than 10-nm resolution. We calculate the dynamical relationship among 3-DOF motion, four piezoelectric displacements, drive frequency, magnetic force, mass of electromagnets, and spring constants of mechanical amplifiers. We also calculate the maximum velocity with no slip of electromagnets because the no-slip condition is significant for positioning repeatability. In several experiments, we have checked the theoretical validity and positioning repeatability. The design procedure, basic performance, and chip-mounting applications are also discussed for cultivating flexible, compact, low-inertia, and omnidirectional precise positioning technology.