Abstract: Disclosed is a work vehicle coordinating system configured to carry out a ground work by a main work vehicle and an un-manned controlled sub work vehicle that follows up the main work vehicle. This system includes a main-vehicle position detection module, a sub-vehicle position detection module, a main-vehicle traveling path calculation section, a turning detection unit, a work traveling target calculation section, a turn traveling target calculation section, and a steering control section.

Abstract: Disclosed is a work vehicle coordinating system configured to carry out a ground work by a main work vehicle and an un-manned controlled sub work vehicle that follows up the main work vehicle. This system includes a main-vehicle position detection module, a sub-vehicle position detection module, a main-vehicle traveling path calculation section, a turning detection unit, a work traveling target calculation section, a turn traveling target calculation section, and a steering control section.

Abstract: A turn control system for a four wheel drive vehicle which includes an accelerating transmission for driving the right and left steerable wheels at a greater average velocity than the right and left non-steerable wheels. A steering device and a switching device are interlocked such that a change speed device is operable in the accelerating transmission when the steerable wheels are steered in excess of a predetermined angle. An inner one of the steerable wheels with respect to a turning circle has a maximum steering angle .beta.1 which is set to form the following expression:secant .beta.1>Kwhere K is a ratio of the greater average peripheral velocity of the right and left steerable wheels when driven by the accelerating transmission with respect to the peripheral velocity of the right and left non-steerable wheels.