Caterpillar Inc.

Stephen R Olson

William James Tate

Giles Kent Sorrells

Craig L Koehrsen

Karl W Kleimenhagen

Automatic vehicle speed retarding control through actuation of wheel

An electronic control is provided for controlling the drive speed of a supplemental drive relative to an engine driven main drive of a vehicle. A fluid pump driven by the engine provides pressurized fluid flow. The supplemental drive is driven by the pressurized fluid. A main drive sensor senses the speed of the main drive and responsively produces a main drive speed signal. A command knob is provided for selecting a desired speed relationship between the main and supplemental drives. A knob sensor senses the position of the command knob and responsively produces a modifier signal. A modifier circuit receives the main drive speed and modifier signals and responsively produces a modified main drive speed signal. A supplemental drive sensor senses the speed of the supplemental drive and responsively produces a supplemental drive speed signal. A processor produces an error signal responsive to a difference between received modified main and supplemental drive speed signals. The processor produces a first signal responsive to a product of the error signal and a preselected constant, produces a second signal responsive to an integral of the error signal, produces a third signal responsive to a derivative of the error signal and produces a pump control signal in response to a sum of the first, second, and third signals. An actuator receives the pump control signal and responsively adjusts the pump output.

Supplemental front wheel drive control system

Supplemental front wheel drive control system and method

An electronic control is provided for a vehicle having an engine, a main drive driven by the engine, a fluid pump driven by the engine for providing pressurized fluid, and a supplemental drive driven by the pressurized fluid. The electronic control includes a main drive sensor for sensing the speed of the main drive and responsively producing a main drive speed signal. A vehicle speed sensor senses the speed of the vehicle relative to the ground and produces a vehicle ground speed signal. A pressure sensor senses the pressure of the pressurized fluid supplied to the supplemental drive by the pump and responsively produces an actual pressure signal. A processor receives the main drive speed, vehicle ground speed, and actual pressure signals, produces a slip ratio signal responsive to a ratio of the main drive speed and vehicle ground speed signals, produces a desired pressure signal responsive to the slip ratio signal, produces an error signal responsive to a difference between the desired and actual pressure signals, and controls the fluid pressure in the supplemental drive in response to the error signal.

Method and apparatus for controlling a supplemental vehicle drive in

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Peoria, IL, United States of America

Stephen R Olson