Patent ID: 7251935

Claim:
A hydraulic control system, comprising: a fluid actuator having a first chamber and a second chamber; a first metering valve having a valve element movable between a first position at which pressurized fluid is allowed to flow into the first chamber to facilitate movement of the fluid actuator in a first direction, and a second position at which pressurized fluid is blocked from flowing into the first chamber; a second metering valve having a valve element movable between a first position at which fluid is allowed to flow from the second chamber to facilitate movement of the fluid actuator in the first direction, and a second position at which fluid is blocked from flowing from the second chamber; at least one fluid sensor associated with the fluid actuator and configured to generate a load signal indicative of a load on the fluid actuator; an operator interface device movable to generate a desired velocity signal indicative of an operator-desired velocity of the fluid actuator; and a controller in communication with the first and second metering valves, the at least one fluid sensor, and the operator interface device, the controller configured to move the valve element of the first metering valve to a position between the first and second positions based on the desired velocity signal and to move the valve element of the second metering valve to a position between the first and second positions based on the load signal and a desired pressure in the second chamber.