Abstract: In some applications, a piston of a hydraulic actuator may move at high speeds, and large undesired forces may be generated if the piston reaches an end-stop of the hydraulic actuator at a high speed. The undesired forces may, for example, cause mechanical damage in the hydraulic actuator. A controller may receive information indicative of the piston reaching a first position at a first threshold distance from the end-stop, and, in response, may modify a signal to a valve assembly controlling flow of hydraulic fluid to and from the hydraulic actuator. Further, the controller may receive information indicative of the piston reaching a second position at a second threshold distance closer to the end-stop of the hydraulic actuator, and, in response, the controller may further modify the signal to the valve assembly so as to apply a force on the piston in a away from the end-stop.

Abstract: The present invention is directed to a method and apparatus for reducing off-track writes in a data storage device. In one embodiment, a command is received to perform a write operation using a write head at a first location on a disk surface. A determination is made as to whether to perform or inhibit the write operation using an equation having a tunable acceleration coefficient. The equation is used to predict a position error signal (PES) value for a write head at a servo sector that immediately circumferentially follows the first location (i.e., there are no intervening servo sectors between the servo sector and the first location). If the predicted PES value is outside of (e.g., greater than or less than) a predetermined threshold, an off-track write is likely to occur and the write operation is inhibited.