A method of brake steering in a four-wheel drive utility vehicle having a driven front axle carrying at least two front wheels, a driven rear axle carrying at least two rear wheels, a powertrain delivering torque to the front and rear axles via a connecting shaft, a controlled clutch arrangement in the connecting shaft operable to vary the distribution of delivered torque between the front and rear axles, and independently operable service brakes on each of the front and rear wheels. The method comprises, on the vehicle entering a turn, applying the service brakes of the front and rear wheels on the inside of the turn and adjusting the clutch arrangement to adapt the share of the available torque between the front and rear axles. Additional braking force may be applied from independently operable park brakes on the rear wheels in inverse relationship to the level of service brake force applied.

A method of brake steering in a four-wheel drive utility vehicle having a driven front axle carrying at least two front wheels, a driven rear axle carrying at least two rear wheels, a powertrain delivering torque to the front and rear axles via a connecting shaft, a controlled clutch arrangement in the connecting shaft operable to vary the distribution of delivered torque between the front and rear axles, and independently operable service brakes on each of the front and rear wheels. The method comprises, on the vehicle entering a turn, applying the service brakes of the front and rear wheels on the inside of the turn and adjusting the clutch arrangement to adapt the share of the available torque between the front and rear axles. Additional braking force may be applied from independently operable park brakes on the rear wheels in inverse relationship to the level of service brake force applied.

A steering control system for a commercial vehicle having braking and steering systems. The braking system brakes dissymetrically side wheels of the vehicle. The steering system steers the vehicle based on a steering signal. The steering control system includes selection and control modules. The selection module switches between first and second steering modes. The first mode indicates steering of the vehicle by turning vehicle wheels. The second mode indicates steering of the vehicle by generating a braking signal for at least one wheel providing a yaw moment applied to the vehicle. The control module generates the first signal indicating a steering demand in the first mode and a second signal indicating a steering demand in the second mode. The control module provides the first signal to the steering system and the second signal to the braking system to brake the vehicle dissymetrically to steer the vehicle with the yaw moment.

A steering control system for a commercial vehicle having braking and steering systems. The braking system brakes dissymetrically side wheels of the vehicle. The steering system steers the vehicle based on a steering signal. The steering control system includes selection and control modules. The selection module switches between first and second steering modes. The first mode indicates steering of the vehicle by turning vehicle wheels. The second mode indicates steering of the vehicle by generating a braking signal for at least one wheel providing a yaw moment applied to the vehicle. The control module generates the first signal indicating a steering demand in the first mode and a second signal indicating a steering demand in the second mode. The control module provides the first signal to the steering system and the second signal to the braking system to brake the vehicle dissymetrically to steer the vehicle with the yaw moment.

A method of controlling a vehicle during a braking operation includes providing a first and a second brake actuator, a brake input device, a steer input device, and a cross-drive transmission having two outputs and a controller. The method includes detecting a first output speed at the first output and a second output speed at the second output, and receiving a brake input request and a steer input request. The method also includes determining a differential output speed based on the first output speed and the second output speed, and comparing the differential output speed to a first threshold, the brake input request to a second threshold, and the steer input request to a third threshold. The method includes determining the first or the second output is locked during the braking operation, and controlling the first or the second brake actuator based on which output is determined to be locked.

A method of controlling a vehicle during a braking operation includes providing a first and a second brake actuator, a brake input device, a steer input device, and a cross-drive transmission having two outputs and a controller. The method includes detecting a first output speed at the first output and a second output speed at the second output, and receiving a brake input request and a steer input request. The method also includes determining a differential output speed based on the first output speed and the second output speed, and comparing the differential output speed to a first threshold, the brake input request to a second threshold, and the steer input request to a third threshold. The method includes determining the first or the second output is locked during the braking operation, and controlling the first or the second brake actuator based on which output is determined to be locked.

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.

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 steering axle drive assembly includes a steering axle having opposite ends, a wheel pivotally connected with each steering axle end, and a control mechanism. The wheels are operated by the control mechanism for rotation about a vertical axis and a horizontal axis. When the axle is connected with a vehicle, the control mechanism controls the steering axle wheels independent of other wheels of the vehicle, such as the main drive wheels, to steer and drive the vehicle from an origin in any direction without passing through the origin. Preferably, a motor or linear actuator controls the rotation of the steering axle wheels. The steering axle drive assembly can be further improved by including an angled axle.

Systems and methods are provided herein for operating a vehicle in a front dig mode. The front dig mode is engaged in response to determining that speed of the vehicle is below a speed threshold and determining that the amount that at least one of the front wheels of the vehicle is turned exceeds a turn threshold. While operating in the front dig mode, forward torque is provided to the front wheels of the vehicle. Further, resistance is applied to forward rotation of the inner back wheel of the vehicle. Yet further, forward torque is provided to the outer back wheel of the vehicle.