Deere + Company

Walter Craig Wright

David V Rotole

Thomas Daryl Bebernes

Thomas A Nichols

Mitchell R Usasz

Eric Ryan Lang

Kyle R Teach

Charles J Bowden

Dale H Killen

Stephen E O'Brien

Eric M Thies

Keith Wayland Gray

Tom Morrison

Keith Craig Gray

A steering system and method is described for a vehicle having steerable front and rear wheels, and a steering input device for receiving manual steering input. Front and rear hydraulic steering devices may be coupled, respectively, to the front and rear wheels. Front and rear valve assemblies may be configured, respectively, to steer the front and rear wheels. In a manual steering mode, the front valve assembly may be disabled with respect to the front steering device, and the front hydraulic steering device may steer the front wheels based upon the manual steering input. In a rear steering assist mode, a rear steering command may be determined based upon the manual steering input, and the rear wheels steered based upon the rear steering command. In an automated steering mode, the front and rear wheels may be automatically steered based upon a target path of travel for the vehicle.

Multi-mode steering control for a vehicle

A steering system and method for a vehicle having steerable front and rear wheels has rear hydraulic steering device that may be coupled to one or more of the rear wheels. A rear valve assembly may hydraulically control the rear hydraulic steering device to steer the rear wheels based upon a rear steering command from a controller. In a manual steering mode, the controller does not determine a rear steering command for the rear valve assembly such that the rear wheels are freely rotatable. In a rear steering assist mode, the controller determines the rear steering command based upon, at least in part, the manual steering input.

Rear steering control for a vehicle

A steering system and method are described for a vehicle having steerable front and rear wheels. A rear hydraulic steering device may be coupled to one or more of the rear wheels. A rear valve assembly may hydraulically control the rear hydraulic steering device to steer the rear wheels based upon a rear steering command. In a rear steering assist mode, the rear steering command may be determined based upon a manual steering input received at a steering input device. In an automated steering mode, the rear steering command may be determined based upon a target path of the agricultural vehicle that is determined independently of the manual steering input.

A method of adjusting a hydraulic drive system includes determining a forward park position value, a reverse park position value, an initial forward position value, and an initial reverse position value of a control device and using these values to calculate a forward buffer value and a reverse buffer value. The forward buffer value and the reverse buffer value are used to determine an adjustment amount for the drive system. The adjustment amount can be used to properly adjust a drive system to avoid system errors.

System and method for calibrating a hydraulic drive system

A pressure control system is described for a vehicle having a hydraulically actuated header. The system may include a hydraulic lifting circuit for raising and lowering the header, a hydraulic float circuit for floating the header, and a drain tank. A lifting circuit control valve may be configured to control drainage of hydraulic fluid from the hydraulic lifting circuit to the drain tank. A float circuit control valve may be configured to control drainage of hydraulic fluid from the hydraulic float circuit to the drain tank. A user interface may be configured to receive one or more inputs to control drainage of hydraulic fluid from the hydraulic circuits. Based upon the one or more inputs, at least one of the control valves may be opened, in order to depressurize, respectively, one of the hydraulic circuits.

Pressure control for hydraulically actuated agricultural headers

A steering system and method are described for a vehicle having steerable wheels, with steering of the wheels controlled, at least in part, by a valve assembly. A ground speed of the vehicle may be determined. Whether a steering command is being provided to a valve assembly may also be determined. An operational pressure at the valve assembly may be determined with a pressure sensor. A threshold pressure may be determined based upon the ground speed and/or whether a steering command is currently being provided. The operational pressure may then be compared with the operational pressure, and steering control with the valve assembly disabled based upon the comparison.

Fault detection for steering control for a vehicle

A four-bar linkage is provided as a mechanical interface for transferring respective outputs from a speed/direction control device and a hydraulic steering cylinder to displacement control arms of a pair of pumps of a dual-path hydrostatic transmission including a pair of motors respectively coupled for driving a pair of front wheels of a vehicle. The hydraulic steering cylinder is fixed and has a piston rod slidably coupled to an input arm of the four-bar linkage in such a way that a rotation speed decrease occurs as the arm and a linked control plate are pivoted from a neutral position, the control plate transferring pivotal movement to effect differential movement of the displacement control arms. This results in the vehicle speed decreasing during a turn.

Steering linkage interface between steering cylinder and ground drive pump displacement control arms

A cylinder position sensing system includes a cylinder housing which slidably receives a rod or shaft element. The cylinder housing has an end piece which slidably receives the shaft element. A first axial groove is formed in the shaft element, and a first magnet member is mounted in the first groove. A second helical groove is formed in the shaft element and is spaced apart from the first groove. A second magnet member is mounted in the second groove. A magnetic field sensor is mounted in the cylinder housing so that the sensor generates an output signal as a function of a relative distance between the first and second magnet members as the second element moves with respect to the first element. Preferably, the shaft element includes a central cylindrical shaft and a hollow cylindrical sleeve mounted over and receiving the shaft. Preferably, the first and second grooves are formed in an inner surface of the sleeve, and the sleeve and the end piece are formed of nonferrous material.

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Pella, IA, United States of America

Walter Craig Wright