A vehicle includes a rear steering system and a front differential hydraulic drive system. A first front drive control valve is operable to output a defined fluid flow in response to a steering command input. A second front drive control valve is operable to selectively divert a portion of the defined fluid flow output from the first front drive control valve. When the vehicle is operating in a pre-defined condition, a steering controller may control the second front drive control valve to divert a portion of the defined fluid flow from the first front drive control valve to define a reduced fluid flow, which is communicated to the front differential hydraulic drive system, to reduce a steering ratio of the front differential hydraulic drive system relative to the rear steering system, to desensitize steering provided by the front differential hydraulic drive system.

A vehicle includes a rear axle having wheels, friction brakes associated with the wheels, and a driver-actuatable input. A vehicle controller is programmed to, in response to the vehicle being in drift mode and the driver-actuatable input being actuated: command zero torque to the wheels, regardless of a driver-demanded torque, for a duration of time; command engagement of the friction brakes responsive to the duration of time ending; and command torque to the wheels responsive to a speed of the wheels being less than a threshold.

A harvester and a method for harvesting a crop is disclosed. The harvester includes two track drives positioned on opposite ends of a front axle of the harvester, each of the track drives including two main wheels that are arranged successively in the driving direction of the harvester, at least one auxiliary wheel positioned between the main wheels, and at least one track that surrounds the main wheels. The auxiliary wheel can interact with a bottom section of the track so that the forces to be deflected via the particular track drive into ground can be deflected at least proportionately using the auxiliary wheel. To reduce the shearing forces into the ground when the harvester turns, a control unit, depending on the steering angle of the harvester, controls a lifting unit to lift a front main wheel of a particular track drive from its home position to a lifted position.

A harvester and a method for harvesting a crop is disclosed. The harvester includes two track drives positioned on opposite ends of a front axle of the harvester, each of the track drives including two main wheels that are arranged successively in the driving direction of the harvester, at least one auxiliary wheel positioned between the main wheels, and at least one track that surrounds the main wheels. The auxiliary wheel can interact with a bottom section of the track so that the forces to be deflected via the particular track drive into ground can be deflected at least proportionately using the auxiliary wheel. To reduce the shearing forces into the ground when the harvester turns, a control unit, depending on the steering angle of the harvester, controls a lifting unit to lift a front main wheel of a particular track drive from its home position to a lifted position.

A method for executing multi-mode turns with a work vehicle includes transmitting initial steering and braking commands for controlling an operation of a steering actuator(s) and a steering brake(s), respectively, of the work vehicle to initiate execution of a multi-mode turning operation. The method also includes determining allowable steering and braking rates for the work vehicle based at least in part on an actual steering rate and an actual braking rate, respectively, of the work vehicle during execution of the multi-mode turning operation, and determining updated steering and braking commands based at least in part on the allowable steering and braking rates. In addition, the method includes transmitting the updated steering and braking commands to control the operation of the steering actuator(s) and the steering brake(s), respectively, to continue execution of the multi-mode turning operation.

A vehicle control system for reducing turn radius of a vehicle may include electric motors associated with front and rear wheels of the vehicle. The system may further include a plurality of vehicle sensors to receive information including driving surface type, vehicle speed and handwheel position. The system may also include a controller operably coupled to the electric motors and the sensors to control wheel slip during a turn based on the driving surface type, the vehicle speed and the handwheel position.

A hydraulic system for controlling a pair of steerable caster wheels includes a left steering command valve, a right steering command valve, and a rear steering control valve. A supply pressure fluid circuit interconnects a pressure source and the rear steering control valve. A command valve supply fluid circuit interconnects the rear steering control valve with both the right steering command valve and the left steering command valve. A left side steering fluid circuit interconnects a left side actuator and the left steering command valve. A right side steering fluid circuit interconnects a right side actuator and the right steering command valve. A fluidic tie rod fluid circuit interconnects both the left side actuator and the right side actuator with the rear steering control valve. A tank return fluid circuit interconnects the rear steering control valve, the left and right steering command valves, and a tank.

A parking control apparatus, for a vehicle including a plurality of wheels, that includes: a processor that is configured to: individually control the wheels to be braked, released, or driven, and, based on control of the wheels, turn the vehicle about an axis that is perpendicular to ground is disclosed.

A hydraulic control system for steering rear caster wheels of a work machine. The control system has a steering mode that proportionally controls the steering of rear caster wheels while compensating the circuit to keep steering performance independent from the load generated by the rear caster wheels, a no steering mode that maintains the position of the rear caster wheels in the absence of a steering command, and a freewheeling mode that permits the rear caster wheels to rotate freely 360°.

The present concept is a continuously variable speed transmission and steering differential. It includes a laterally extending central drive axle driven by an external power source, two pairs of drive sheaves mounted to drive axles, and a means for transmitting rotational energy from the drive sheaves to the drive axles. There are two extended shift arms spaced apart for controlling the positioning of movable drive sheaves. Narrowing or increasing the gap between shift arms, does the same for the gap between the drive sheaves, increasing or decreasing the gear ration respectively which provides speed control. Shifting the shift arms left or right varies the gear ratio between the left and right pair of sheaves, providing differential speed between the left and right driven axles, which provides steering control.