A controller provided in a bulldozer maintains the engagement of an inside steering clutch over a predetermined period beginning from a switching start point at which switching starts, when switching from a slow turn mode to a pivot turn mode, and when switching from the pivot turn mode to the slow turn mode, maintains the braking of an inside steering brake over a predetermined period beginning from a switching start point at which the switching starts.

A utility vehicle having operator selectable onboard and remote controls also includes a prime mover and a power generating device driven thereby, first and second electric wheel motors, and a drive controller in communication with the wheel motors to control the output thereof and in communication with the onboard controls. A radio control receiver is in communication with the drive controller and with a radio control transmitter having steering and speed controls. The vehicle includes a control mode switch having a first position where the drive controller receives steering and speed control inputs from the onboard controls, and a second position where the drive controller receives steering and speed control inputs from the radio control transmitter.

In one embodiment, a wheelchair includes a drive wheel, a motor coupled to the drive wheel, and a user input device. The motor, in one embodiment, is configured to rotate the drive wheel. The user input device may be configured to send a signal for controlling a motor parameter. The wheelchair, in one embodiment, includes a caster wheel and a castor sensor configured to sense a caster angle. In one embodiment, a controller is configured to receive the signal for controlling the motor parameter and a signal from the caster sensor and to determine a first turn rate parameter of the wheelchair based upon the received signal from each of the input device and the caster sensor.

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.

In an electric power steering device including a controller, which is configured to carry out feedback control for a motor including independent two coil winding groups and being configured to rotate a steering mechanism of a vehicle, when one of the two groups recovers from a failure that has occurred in the one group while control is continued solely by another group due to the failure, the controller resumes cooperative control by the two groups, and when starting the cooperative control, sets target current values of the one group and the another group to values different from a final target current value based on an actual current value or a target current value of the another group at a time of the recovery, to thereby output respective control amounts for the cooperative control.

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.

A zero turn radius vehicle with a single steered wheel may include a pair of power transfer mechanisms driving a pair of wheels, an operator control mechanism for controlling the steering, speed and direction of the vehicle and a controller in communication with the control mechanism. A steerable wheel is located adjacent the front of the vehicle frame, on a first side of the vehicle frame and an electric actuator is connected to the controller for steering the front steerable wheel. A second, non-steerable front caster wheel is located on a second side of the vehicle frame. A damper is connected to the non-steered wheel to dampen rotation of the non-steered wheel about a non-steered wheel pivot axis The controller controls the pair of power transfer mechanisms and the electric actuator based on operator input.

A smart steering control system a paving or texturing machine receives path elements corresponding to current and future positions of the machine. By comparing the current and future elements, an expected completion time is derived for exiting the current position and entering the future position; the smart steering control system synchronizes adjustments of the machine's steerable tracks from the current path to the future path. The smart steering control system functions as a virtual tie rod, preventing damage, enhancing the traction control and pulling power of the machine, and preserving the operating life of its components.