Patent ID: 7142968

Claim:
In a hitch control system having a hitch mounted on a vehicle, a hydraulic actuator for moving the hitch, a hitch position sensor, a valve for controlling flow of hydraulic fluid to the actuator and an electronic hitch control unit for supplying valve control signals to the valve, a method of determining a hitch raise rate calibration value, the method comprising: applying a first estimated control signal S 1 to the valve to cause the hitch to raise; determining a first hitch velocity V 1 as the hitch moves in response to the first control signal; applying a second estimated control signal S 2 to the valve; determining a second hitch velocity V 2 as the hitch moves in response to the second control signal; and calculating the raise rate calibration value as a function of the first and second estimated control signals, the first and second hitch velocities, and a desired hitch raise rate.