Abstract: A method and apparatus are disclosed for controlling the cross slope angle cut by the blade of an articulated frame motorgrader being steered through a turn, operated in a straight frame mode, in a crabbed steering position and/or traveling in a non-horizontal plane. The blade angle is sensed and controlled such that the sensed blade angle is maintained substantially equal to a calculated blade angle. In a first embodiment, the blade angle calculation is performed using the equation: tan BS=(sin .tau.')(tan R)+(cos .tau.')(tan CS) where BS is the required blade slope angle of said blade relative to horizontal; .tau.' is a rotational angle of the blade with respect to the blade's direction of travel projected into horizontal; R is an angle between the blade's direction of travel and horizontal; and CS is the desired cross slope angle which is entered by an operator of the motorgrader. In a further embodiment, the blade angle calculation is performed using the equation: tan BS=(sin .tau.")(tan R')+(cos .tau.

Abstract: A method and apparatus are disclosed for controlling the cross slope angle cut by the blade of an articulated frame motorgrader operated in the crabbed steering mode wherein the articulation angle of the motorgrader frame is sensed and used to calculate the blade angle relative to horizontal required to maintain a desired cross slope angle. The blade angle is sensed and controlled such that the sensed blade angle is maintained substantially equal to the calculated blade angle.

Abstract: A method and apparatus are provided for controlling the working depth of a bucket for an excavating machine having an outreach boom which is pivotally attached at one end to the machine, a downreach boom pivotally attached to the opposite end of the outreach boom, a digging bucket pivotally attached to the end of the downreach boom opposite to that to which the outreach boom is attached, and hydraulic power cylinders for moving the pivotally interconnected elements. A laser beam is projected at a reference height and a beam sensor mounted on the outreach boom of the machine detects the beam by means of a plurality of individual sensor locations. The angular orientation of the downreach boom relative to vertical is detected and a microprocessor controller connected to the beam sensor and the angle sensor repetitively defines, as a function of the angular orientation of the downreach boom, one of the plurality of individual sensor locations as an on-grade sensor location.