Electromagnetic wobble micromotor for microrobots actuation

Abstract

A key point for microrobots is represented by the actuation system, which enables them to move and manipulate objects, if required. In the field of mechatronic medical micro-instruments a micromotor could be used for the actuation of endoscopes lenses and in powered laparoscopic tools, for examples micro-grippers or micro-scissors, drug delivery micro-pumps and endoscopic intra-corporeal autonomous capsules. The size range of interest goes from centimetres down to hundreds of microns. Scaling down the overall dimensions of robots, traditional actuators are no longer feasible and it becomes essential to employ innovative systems. In this paper the optimization of an existing wobble micromotor is presented and its implementation as microactuator for biomedical devices has been demonstrated. The Finite Element Method (FEM) analysis has been applied on a variable reluctance wobble motor ( Φ 5 mm × 5 mm) in order to evaluate all the electric and magnetic quantities necessary for the optimization of the micromotor geometry and performances and to compute its electromechanical characteristic. Thanks to its small size, the micromotor has been assembled inside swallowable modules, both in single and in twin configuration. Motor's simple structure and low cost opens a very wide market where the actuator could be commercialized, as for example consumer electronics, mechatronic medical micro-instruments, robotics, micromanipulators, dosing systems and mobile robots.