Patent ID: 7857085

Claim:
A vehicle comprising four or more wheels, at least two of which are driven wheels and at least two of which is steerable, where the axes of rotation of all wheels lie substantially in the same horizontal plane, and where the steerable wheels are turnable about substantially vertical axes by means of hydraulic or electric actuators, where the speed of each driven wheel is controlled by means of a speed-correcting differential which is close-coupled to each driven wheel, where the first input to the said differential is from an engine via a main gear box and a series of right angle drives, and the second input to the said speed correcting differential is provided by means of a speed correcting electric or hydraulic motor which is close coupled to the said differential, where the speed of each driven wheel is determined by the speed of the first input, which will be the same for all driven wheels, and the speed and direction of rotation of the speed correcting electric or hydraulic motor, where the speeds of the driven wheels are independently and positively controlled so that they tend to produce a single centre of curvature for the path of the vehicle, and where all the wheel angles are positively controlled to produce a single driver-selected centre of curvature for the path of the vehicle, and where the driven wheel speeds and all the wheel angles are integrated so that the first centre of curvature is made identical to the second centre of curvature which is selected by the driver.