Implement weight and center of gravity determination based on hitch cylinder pressure

1. A method for controlling a ground-engaging implement coupled to an agricultural tractor, the method comprising the steps of:

providing a ground-supported agricultural tractor having a three-point hitch movable in upward and downward directions by at least one hydraulic actuating cylinder;

providing a ground-engaging implement attached to the hitch of the tractor;

providing a hitch control apparatus for managing the upward/downward position of the hitch to maintain a desired draft load or position on the tractor, the hitch control apparatus having programming implementing theory and equations to derive implement weight and center of gravity location;

providing an actuating cylinder pressure sensor for measuring hydraulic pressure in the actuating cylinder and communicating a pressure value to the hitch control apparatus;

providing a hitch position sensor for measuring upward/downward position of the hitch and communicating a position value to the hitch control apparatus;

positioning the implement in a first position with no portion of its weight supported by the ground;

generating a first pressure value by the actuating cylinder pressure sensor;

generating a first position value by the hitch position sensor;

communicating the first pressure value and the first position value to the hitch control apparatus;

positioning the implement in a second position;

generating a second pressure value by the actuating cylinder pressure sensor;

generating a second position value by the hitch position sensor;

communicating the second pressure value and the second position value to the hitch control apparatus; and

deriving from the first and second pressure and position values of the hitch, in accordance with the programming of the hitch control apparatus, an implement weight and a location of an implement center of gravity by the hitch control apparatus;

wherein said center of gravity of said implement is derived from the ratio of said first and second generated pressure values.

2. The method of claim 1 , wherein the position value of hitch includes distances between the hitch points and pivotal couplings of lower and upper links of the hitch.

3. The method of claim 1 , wherein said weight of said implement vehicle is derived from hitch dimensions and as a linear function of the pressure value at a hitch position.

4. A method for controlling a ground-engaging implement coupled to an agricultural tractor, the method comprising the steps of:

providing a ground-supported agricultural tractor having a three-point hitch movable in upward and downward directions by at least one hydraulic actuating cylinder;

providing a ground-engaging implement attached to the hitch of the tractor;

providing a hitch control apparatus for managing the upward/downward position of the hitch to maintain a desired draft load or position on the tractor, the hitch control apparatus having programming implementing theory and equations to derive implement weight and center of gravity location;

providing an actuating cylinder pressure sensor for measuring hydraulic pressure in the actuating cylinder and communicating a pressure value to the hitch control apparatus;

providing a hitch position sensor for measuring upward/downward position of the hitch and communicating a position value to the hitch control apparatus;

positioning the implement in a first position with no portion of its weight supported by the ground;

generating a first pressure value by the actuating cylinder pressure sensor;

generating a first position value by the hitch position sensor;

communicating the first pressure value and the first position value to the hitch control apparatus;

positioning the implement in a second position;

generating a second pressure value by the actuating cylinder pressure sensor;

generating a second position value by the hitch position sensor;

communicating the second pressure value and the second position value to the hitch control apparatus; and

deriving from the first and second pressure and position values of the hitch, in accordance with the programming of the hitch control apparatus, an implement weight and a location of an implement center of gravity by the hitch control apparatus;

wherein said weight of said implement vehicle is derived from hitch dimensions and as a linear function of the pressure value at a hitch position.