A self-driving work vehicle includes: a front wheel unit; a rear wheel unit including a left rear wheel and a right rear wheel; a variable traveling power supply apparatus that supplies rotational drive power to the left rear wheel and the right rear wheel independently; a left operation implement movable along a first path to adjust a rate of the rotational drive power to be supplied to the left rear wheel from the variable traveling power supply apparatus; a right operation implement movable along a second path to adjust a rate of the rotational drive power to be supplied to the right rear wheel from the variable traveling power supply apparatus; a parking brake provided for the variable traveling power supply apparatus; and a controller configured or programmed to cause a parking brake operating module to operate the parking brake.

An agricultural vehicle configured for traveling in a driven-wheel-leading mode and a caster-wheel-leading mode. The agricultural vehicle includes a first driven wheel and a second driven wheel, a caster axle, a first caster wheel and a second caster wheel, and a steering system. The steering system includes a first steering actuator connected in between the caster axle and the first caster wheel, a first sensor connected to the caster axle, and a controller operably connected to the first steering actuator and the first sensor. The controller is configured for actuating the first steering actuator to steer the first caster wheel in the driven-wheel-leading mode and the caster-wheel-leading mode.

A transmission for a vehicle, particularly a skid-steered vehicle, that employs motive power from a prime mover delivered through an input shaft to drive left and right drive shafts at a nominal speed and input power from an electric motor to vary the speed of the left and right drive shafts according to steering commands from a steering control structure. The speed of the left and right drive shafts is directly related to a speed of the input shaft and the nominal speed of the left or right drive shaft is varied upwardly or downwardly by a ratio of the speed of the steering shaft via a speed varying structure. The speed of the left and right drive shafts is simultaneously varied in opposite directions (i.e. upwardly and downwardly) relative to the nominal speed by an equal number of rotations.

A transmission for a vehicle, particularly a skid-steered vehicle, that employs motive power from a prime mover delivered through an input shaft to drive left and right drive shafts at a nominal speed and input power from an electric motor to vary the speed of the left and right drive shafts according to steering commands from a steering control structure. The speed of the left and right drive shafts is directly related to a speed of the input shaft and the nominal speed of the left or right drive shaft is varied upwardly or downwardly by a ratio of the speed of the steering shaft via a speed varying structure. The speed of the left and right drive shafts is simultaneously varied in opposite directions (i.e. upwardly and downwardly) relative to the nominal speed by an equal number of rotations.

A riding lawn care vehicle may include a frame to which at least a first drive wheel and a second drive wheel of the riding lawn care vehicle are attachable, an engine operably coupled to the frame and the first and second drive wheels to provide power to the first and second drive wheels, a steering assembly that includes a first steering lever and a second steering lever, and a work assembly. The first and second steering levers are operably coupled to the first and second drive wheels respectively to facilitate turning of the riding lawn care vehicle based on drive speed control of the first and second drive wheels responsive to positioning of the first and second steering levers. The work assembly is operably coupled to the engine to perform a work function responsive to power received from the engine. Each of the first and second steering levers includes a grip portion. At least one of the first steering lever or the second steering lever includes a control module disposed proximate to and separate from the grip portion. The control module includes a control operator configured to control operation of the engine or the work assembly.

A transmission for a vehicle, particularly a skid-steered vehicle, that employs motive power from a prime mover delivered through an input shaft to drive left and right drive shafts at a nominal speed and input power from an electric motor to vary the speed of the left and right drive shafts according to steering commands from a steering control structure. The speed of the left and right drive shafts is directly related to a speed of the input shaft and the nominal speed of the left or right drive shaft is varied upwardly or downwardly by a ratio of the speed of the steering shaft via a speed varying structure. The speed of the left and right drive shafts is simultaneously varied in opposite directions (i.e. upwardly and downwardly) relative to the nominal speed by an equal number of rotations.

When left and right steering levers are both operated and the operation amount of the left lever is larger than that of the right lever, a controller calculates a correction left operation amount of the left lever according to the operation amount of the right lever, and controls a left steering clutch so as to cause a vehicle body to turn toward the left in accordance with the correction left operation amount. When left and right steering levers are both operated and the operation amount of the right lever is larger than that of the left lever, the controller calculates a correction right operation amount of the right lever according to the operation amount of the left lever, and controls a right steering clutch so as to cause the vehicle body to turn toward the right in accordance with the correction right operation amount.

A transmission for a vehicle, particularly a skid-steered vehicle, that employs motive power from a prime mover delivered through an input shaft to drive left and right drive shafts at a nominal speed and input power from an electric motor to vary the speed of the left and right drive shafts according to steering commands from a steering control structure. The speed of the left and right drive shafts is directly related to a speed of the input shaft and the nominal speed of the left or right drive shaft is varied upwardly or downwardly by a ratio of the speed of the steering shaft via a speed varying structure. The speed of the left and right drive shafts is simultaneously varied in opposite directions (i.e. upwardly and downwardly) relative to the nominal speed by an equal number of rotations.

A bulldozer includes a control unit for controlling left and right steering clutches and left and right steering brakes, thereby executing a turning control of the vehicle. The control unit switches between a clutch control and a brake control on the basis of a differential between an actual turning radius and a target turning radius.

A method for steering a machine while commanded to be in neutral, including: sensing that a transmission is in a neutral setting; applying one or more service brakes into a braking mode; ramping off a steering pump on a hydraulic steering system; sensing a steering command; releasing the one or more service brakes from the braking mode in response to sensing the steering command; and ramping on the steering pump on the hydraulic steering system.