US Patent 9387880 Multi-axis caster angle control system of an extendable wheel assembly

A wheel assembly for vehicle includes a wheel, at least one lower suspension link and one upper part, the wheel being arranged to rotate at 360°, to steer the vehicle around a pivot line, a projection of the pivot line onto a vertical projection plane including a vertical axis passing through a contact point between the wheel and ground defining a caster angle (α) with the vertical axis. The wheel assembly includes a at least one screw arranged to adjust the caster angle (α) such that the position of the upper part is moveable relative to the vehicle along a first degree of freedom and a second degree of freedom.