Patent ID: 6473679
Filing Date: 2002-10-29
Classification: B66F

Abstract:
A method for maintaining a constant angular velocity for a boom of a machine comprising the steps of:pre-selecting a desired angular velocity for a boom of a machine; forming a triangle, the first leg comprising a fixed distance A between a pivot point of the boom to the machine and an attachment point of a boom lift cylinder to the boom, the second leg comprising a fixed distance B between the pivot point of the boom to the machine and an attachment point of the boom lift cylinder to the machine, and the third leg comprising a variable distance C between the attachment point of the boom lift cylinder to the boom and the attachment point of the boom lift cylinder to the machine, distance C varying as the boom lift cylinder extends and retracts to lift and lower the boom; determining the length of distances A, B and C at a first point in time; determining at the first point in time the value of the sine of an angle &thgr; formed by the intersection of the first leg and the second leg; calculating at the first point in time a boom gain value by dividing the product of A, B, and the sine of &thgr; by C; calculating a desired boom lift cylinder velocity at the first point in time by taking the product of the boom gain at the first point in time and the pre-selected desired angular velocity; adjusting an actual boom lift cylinder velocity to equal the desired boom lift cylinder velocity, thereby producing an actual angular velocity of the boom that equals the pre-selected desired angular velocity; and repeating the step of determining the length of distances A, B and C at a first point in time through the step of adjusting an actual boom lift cylinder velocity to equal the desired boom lift cylinder velocity, thereby producing an actual angular velocity of the boom that equals the pre-selected desired angular velocity at a second point in time wherein the length of C and therefore the value of the sine of angle &thgr; are different at the second point in time from the first point in time.