A method of vehicle straight angle motion relative its axial axis by turning the front wheels and simultaneous braking of the external side wheels is offered. The equation describing the condition of four-wheel drive vehicle crab motion is obtained. The purpose of the research is to determine the law of control of torque on the wheels of the car, the realization of which makes crab motion possible. For realization of the aim, the following challenges were solved:
the torque difference on the driving wheels (the braking torque on the outside wheel) that provides “crab motion" is determined;
an analysis of the operational factors influences and design parameters of the vehicle, on the magnitude of the required torque difference, was conducted.
The angle of rotation of the track wheels determines the direction of vehicle movement, and the torque difference on the driving wheels creates a moment stabilizing the position of the vehicle and ensures the straightness of the trajectory of motion.
The linear velocity at which “crab motion" is possible without creating a torque difference on the driving wheels is determined.
In this research analytical correlations describing the process of the vehicle's “crab motion" at the torque difference created by the brake moment on the external (in relation to the conditional center of rotation) wheel are shown.
The charts of the speed dependence of the vehicle, the difference in torque on the driving wheels at different significances of linear accelerations are created. The graphs of the linear acceleration dependence on the linear speed at different design parameters of the vehicle are also presented.
The obtained results allow further development of the algorithm of control and design of the system which provides the vehicle's “crab motion ".