Community Research and Development Information Service - CORDIS

The development of advanced micromotors

For various applications very small motors or actuators are required. Due to different loads the speed and torque capabilities may vary between broad limits. The size of the motor/actuator should be as small as possible (eg, in the region of millimetres and submillimetres). Only with advanced materials (high energy permanent magnets, thin layer technology), can integrated microcomputer control and latest design considerations such micromotors and microactuators be achieved. The main objective of the project is, taking into account the recent developments of improved neodymium iron boron materials and biocompatible materials and microelectronic fabrication techniques and micromechanical fabrication techniques, to make research type millimetre and submillimetre mircomotors/actuators, using electromagnetic and electrostatic principles. In order to make these microdevices of practical use in the foreseeable future, we investigate certain fundamental problems, such as micromechanical properties, mechanical handling and loading, design procedures, assembly strategies, friction and wear of microdevices.

Miniature electric motors with dimensions measured in microns have been manufactured. Scaling analysis shows that as size is reduced electrostatic designs become advantageous. Manufacturing methods for micromotors use processes similar to those of the microelectronic industry where batch processing is an obvious advantage.
The electrostatic micromotors were based on the principal of capacitive induction whereby a voltage on the stator induces a potential on a conducting rotor which then moves to minimize its potential energy.
An analysis has been conducted of the electrostatic field distribution for selected geometries using a 3-dimensional finite element software package.
A novel design has been analysed consisting of a double stator with a rotor between the upper and lower stator sections. Brushless direct current (DC) micromotors of the disc type with etched planar windings have also been built and minilinear actuators have been investigated.

Techniques for generating both 2-dimensional and 3-dimensional finite element models automatically have been developed and by combining the equivalent circuit technique with the automatic model builders an optimization of both 6/8-pole and 6/4-pole configurations of the radial flux motor and the axial flux motor has been achieved.

Reported by

Technische Universitaet Berlin
Echsteinufer 11
1000 Berlin 10
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