Analysis and Experiments on the Force Capabilities of Centripetal-Force-Actuated Microrobotic Platforms

This paper studies the capabilities of a microrobotic platform, driven by vibrating motors, to generate and impart micromanipulation forces of desired type and magnitude. First, an analysis is carried out on the nature of the actuation forces of the motion mechanism of the platform. The results demonstrate that the oscillating nature of these forces does not allow their direct use for micromanipulations. Consequently, further analysis is conducted to identify the conditions, under which the platform´s actuation forces can be exploited for micromanipulations. To this end, a dynamic model of a single-dimensional pushing operation is developed, comprising the dynamics of the platform, the manipulator and the object. It is demonstrated by simulation that the forces imparted on the manipulated object depend on the physical parameters of the platform-manipulator system. Accordingly, a set of nonlinear equations involving platform-manipulator system parameters, is formulated that describes the conditions for developing micromanipulation forces of appropriate type and magnitude. The solution of this set of equations yields a range of parameter values, which are used as guidelines in the design and construction of a manipulator that is capable of applying smooth and controllable forces to manipulated objects. Using the parameter values suggested by the developed analysis, a needle type manipulator, appropriate for force feedback applications, is designed, built, and mounted on an experimental prototype of the microrobotic platform. Using this manipulator, experiments demonstrate the force capabilities of the microrobotic platform and verified the analytical and simulation results.