Power Amplifier Gain Adaptation in Digital Control Systems for Direct Access Storage Devices
Original Publication Date: 1988-May-01
Included in the Prior Art Database: 2005-Feb-15
Digital head positioning servo control systems are used in many disk files to control the motion of the read/write heads. In such systems, power amplifiers are used to produce the voice coil current necessary to move the actuator to which the heads are attached. The digital servo control system can be improved by estimating the power amplifier gain and modifying the control parameters appropriately to reduce the modelling errors, thereby improving the head access time and the off- track errors. Smaller off-track errors lead to lower soft and hard error rates and better file performance. The power amplifier is composed of several discrete analog components, and is therefore subject to component tolerances.