A high speed tracking system using adaptive model-following control

In the time optimal control problem, it is important to select a switching point accurately in order to improve tracking speed performance. However, the accurate selection of the switching point is not an easy task because of the damping coefficient variations and modeling uncertainties in actual systems. To relieve the difficulty and inconvenience of this task, adaptive model-following control (AMFC) is implemented. AMFC can make the controlled plant follow as closely as possible a desired reference model whose switching point can be calculated easily and accurately, assuring that the error between the reference model and the real system approaches zero. The AMFC is applied for a tracking actuator of a magneto-optical disk drive (MODD) to improve its slow tracking performance. According to the simulation and experimental results, an average tracking time as small as 20 ms is obtained for a 3.5 in. magneto-optical disk drive.