Weight optimisation of brush-type wound-field direct current motors

Weight optimised direct current motors have been used lately as actuators for micro-robotics and biomedical equipment. Many techniques have been used in developing permanent magnet and wound-field motors, such as numerical analysis, selecting adequate magnetic material, finite element analysis and optimisation models. Yet, published articles reveal problems with wound-field motors: for example nonproportional geometry, saturated magnetic core, weak output torque and high temperature rise. A mathematical model is introduced in this paper for developing a new design method to overcome these problems. A 900 W DC motor is optimised separately and concurrently with a proportional, integral and derivative (PID) controller, as an example for illustrating the proposed method.