Hydraulic rotary actuator with built-in mechanical position feedback

An actuator assembly comprising:

• a hydraulic pump;
• and
• a rotary actuator comprising:
• a central housing;
• an output shaft that extends through the central housing;
• a vane that is mechanically coupled to the output shaft and divides the central housing into a first chamber and a second chamber;
• and
• a flow control mechanism that is moveable within the central housing and configured to port high pressure to one side of the vane and low pressure to an opposite side of the vane, thereby generating a pressure differential across the chambers;
• wherein the vane rotates within the central housing in response to the pressure differential, and rotation of the vane drives the output shaft;
• and
• wherein the rotary actuator is controlled to control the hydraulic pump to control the flow of hydraulic fluid from the hydraulic pump.

A rotary valve comprising:

• a housing having an interior chamber and a high pressure port and a drain port;
• a control plate rotatable within the housing and coupled to an actuator shaft;
• and an actuator plate rotatable within the housing and coupled to a stepper motor;
• wherein rotational movement of the control plate opens a flow path from the high pressure source, through the actuator plate and to a clockwise chamber of the actuator and movement of the control plate opens a counterclockwise chamber of the actuator to the drain;
• and
• as the actuator plate approaches the position of the control plate, the flow path from high pressure to the actuator chamber is closed.