Apparatus and method for improving dynamic characteristics of a fine- positioning mechanism in a magnetic head/disk tester

摘要

An improved fine positioning mechanism in a magnetic head/disk tester includes a primary position actuator and a primary body that supports a read/write head to be tested, and an auxiliary body and auxiliary actuator. Both actuators operate contemporaneously and in mutually opposite directions. The masses of both bodies and the stiffnesses of both actuators are selected so that a ratio of the stiffness of the actuator to the mass of the body in the primary system is equal to a ratio of the stiffness of the actuator to the mass in the auxiliary system. In addition, the masses of both bodies and the expansion coefficients of both actuators are selected so that a product of the mass of the body with the expansion coefficient of the actuator in the primary system is equal to a product of the mass of the body with the expansion coefficient of the actuator in the auxiliary system. In this manner, forces operating on both bodies are equal in magnitude and opposite in direction and therefore counterbalance each other when the same control voltage is applied to both actuators. This, in turn, eliminates or reduces vibrations in the slide supporting the actuators and therefore the head-positioning settling time is significantly reduced.