Vehicle and a method for controlling steering thereof

Vehicle comprising

• a chassis (2),
• at least two first wheels (3) of a first type, which are arranged to support the chassis when resting on the ground and which are each arranged to be rotatable relative to the chassis not only about a first substantially vertical axis (4) extending through said respective wheels (3), but also about a second axis (5) that constitutes an angle greater than 0° but less than 90° relative to both the first substantially vertical axis (4) and a horizontal axis, such that each said wheel has a contact surface against the ground that defines a rolling point (6) which is horizontally displaced from the first substantially vertical axis (4) and upon one revolution of each said wheel, a circle is traced on the ground by said rolling point (6),
• means (8) for individually controlling the alignment of said wheels relative to the chassis by turning about the first axis (4),
• means (18) for individually driving said wheels,
• a regulation device (9) to regulate the movements of the vehicle in a horizontal plane,
• a control device (7) with a calculation unit (11) arranged to produce signals to control said control and drive means via information from the regulation device to achieve the movement as instructed by the regulation device,
• wherein the regulation device is designed with the capability to, on request of a change of the vehicle's direction in a horizontal plane, order a position for a turning point (B) for the vehicle anywhere in the horizontal plane, the control device's calculation unit is designed to calculate instantaneous desired value of respective said first wheel's angular alignment relative to a lengthwise axis of the vehicle corresponding to the location of said turning point as ordered by the regulation device and send signals to the control means to achieve that alignment, and
• said regulation device comprises
• first means (12, 12′) for displacing a steering line (S) gassing through the turning point (B) of the vehicle from one location (S′) to another (S″) in parallel, and
• second means (15, 15′) for simultaneously displacing said turning point (B) along said steering line (S) from one location (B1) to another (B2).