A controller controls a first drive source and a second drive source based on a rotation speed of a right rear wheel measured by a rotation speed sensor and a rotation speed of a left rear wheel measured by a rotation speed sensor, to thereby independently control a rotation speed of each of a right front wheel and a left front wheel.

Reduction of minimum turning radius of an aerial work platform. Drive motors are provided to driven wheels of the platform respectively, so that the driven wheels can be independently controlled in terms of rotational speed and rotation direction. When the steering angle of steered wheels is at most a first steering angle, constant velocity control is performed, driving both of the driven wheels in the same rotation direction and at the same rotational speed. When the steering angle exceeds the first steering angle and is at most a second steering angle, differential control is performed, reducing the rotational speed of the driven wheel on the inside in the turning direction relative to the driven wheel on the outside in the turning direction. When the steering angle exceeds the second steering angle, counter-rotation control is performed, counter-rotating the driven wheel that is on the inside in the turning direction.

Systems for controlling the speed and direction of vehicles such as tractors, including vehicles that have low to zero turning radius capability. Systems include steering and speed coordination systems that control the direction and speed of rotation of vehicle drive units.

Systems for controlling the speed and direction of vehicles such as tractors, including vehicles that have low to zero turning radius capability. Systems include steering and speed coordination systems that control the direction and speed of rotation of vehicle drive units.

Self-propelled vehicles that include swiveling caster wheels and independent drive wheels are disclosed. The self-propelled vehicles are selectively steered in a caster wheel steering mode or a drive wheel steering mode. The vehicle includes a steering position sensor to measure the position of the steering system. A control unit varies the rotational speed of first and second drive wheels based at least in part of the signal from the steering position sensor.

Self-propelled vehicles that include swiveling caster wheels and independent drive wheels are disclosed. The self-propelled vehicles are selectively steered in a caster wheel steering mode or a drive wheel steering mode. The vehicle includes a steering position sensor to measure the position of the steering system. A control unit varies the rotational speed of first and second drive wheels based at least in part of the signal from the steering position sensor.

An articulated tractor comprises a front frame, a rear frame articulated to the front frame by a central articulation, and a pivotable hitch carried by one of the front frame and the rear frame. The hitch is pivoted during steering. Front wheels are offset from the rear part of the tractor.

A method for modifying a brake application of a combination vehicle comprises receiving a temperature signal of a first brake pad of a first brake assembly and receiving a temperature signal representative of a temperature of a second brake pad of a second brake assembly. The temperatures are compared to a first predetermined temperature. The method will determine if service brakes are being applied by a driver and compare a wheel speed of one axle of the tractor with the wheel speed of a second axle of the tractor of the combination vehicle. The method will determine a brake drag exists in response to both the first and the second brake pad temperature being greater than the first predetermined temperature, the first axle wheel speed being less than the second axle wheel speed and the service brakes not being applied by the driver.

A small radius- or zero radius-turn vehicle that may be steered by differentially-driven rear drive wheels and by at least one electronically-controlled, steerable front wheel. A device, e.g., one or more levers, may be provided that controls both speed and direction of the drive wheels. A sensor may be provided that detects a position of the lever(s). A controller may calculate a steering angle of the front wheel based upon the position, and issue a command to an actuator associated with the front wheel. The actuator may rotate the front wheel to an electronically calculated steering angle in response to the command.

In some embodiments, a vehicle may include a frame having longitudinal axis. The vehicle may include a steering assembly having a steering input and at least one wheel. The steering assembly may be coupled to the frame and configured to steer the vehicle based on input from a steering input. The vehicle may include a first drive wheel and a second drive wheel. The vehicle may include a steering position sensor configured to detect steering input including a position of the steering input and at least one of i) a rate of change of position of steering input and ii) steering position time. The vehicle may include at least one controller configured to process a signal from the steering position sensor and, in response to the processed signal, drive the first drive wheel and the second drive wheel, the first drive wheel being driven independent of the second drive wheel.