Abstract: A controller for a voice coil actuator includes sensors that are connected with the actuator probe to monitor both the linear and angular position of the probe, as well as the axial and rotational forces on the probe. Using predetermined instructions, the probe can be controlled in either an open loop mode or in a closed loop feedback mode, for either static or dynamic operations. For static operations, the axial and rotational forces on the probe can be controlled by referencing set values for the forces which are to be applied to/by the probe. For dynamic operations, in addition to the axial and rotational forces on the probe, the linear and angular movements of the probe can be controlled. In the closed loop mode, linear and angular positions, velocities, and accelerations can be used for control.

Abstract: A method and device for moving a probe assembly into soft contact with a work surface includes initially placing the probe into an approach position. Advancement of the probe along a substantially perpendicular path toward the work surface is then controlled by applying a restraining force on the probe. This resisting force is decreased until the weight of the probe assembly just overcomes the static friction forces that are acting on the probe. After the static friction forces are overcome, the probe advances along a path toward the work surface. By monitoring this advancement, soft contact of the probe with the work surface can be determined when the velocity of the probe changes to zero. First, the position of the probe can be monitored to advance the probe along the path through a known travel distance. Second, the velocity of probe advancement can be monitored to indicate soft contact when velocity changes to zero.