Determination of the forces present in an electrostatic micromotor

A detailed knowledge of the distribution of forces in a micromechanical system such as a micromotor is of great value at the design stage of such devices. It is preferable to analyse these forces using simulations of the system before the design is built and tested, since the cost of fabrication of micromechanical systems is high. This paper presents results of three dimensional simulations of a practical design of a high aspect ratio micromotor. The analysis of the electrostatic fields in the micromotor geometry gives detailed profiles of the forces acting on the various microstructures. These results indicate high localisation of forces in certain areas of the micromotor. An example is given of the application of the force analysis results in the prediction of frictional effects on the rotor caused by the axial force exerted on it