Abstract: 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.

Abstract: 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.

Abstract: 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.