Actuator Limit Controller

摘要

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.

主权项

1. A method comprising:
receiving, at a controller, a command for moving a piston of a hydraulic actuator at a given speed in a given direction, wherein the hydraulic actuator includes a first chamber and a second chamber, and wherein a valve assembly couples a source of pressurized hydraulic fluid to the first chamber and couples the second chamber to a return line; based on the command, the controller providing a signal to operate the valve assembly to provide the pressurized hydraulic fluid to the first chamber and allow hydraulic fluid in the second chamber to flow from the second chamber to the return line so as to cause motion of the piston at the given speed in the given direction; receiving position information indicative of the piston reaching a first position at a first threshold distance from an end-stop of the hydraulic actuator; in response, the controller modifying the signal to the valve assembly so as to reduce a speed of the piston; receiving position 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 further modifying the signal to the valve assembly to cause the hydraulic fluid in the second chamber to apply a force on the piston in a direction away from the end-stop.