A technology of mechanically classifying a switching operation between a traveling mode and a special moving mode is provided to prevent a mode switching misoperation. A traveling mode switching mechanism of a four-wheel independent steering type vehicle includes a shift gate which is disposed by forming a moving path of a shift lever, and grouping a traveling mode and a special moving mode. Additionally, a mode switching differentiation devices differentiates a mode switching operation of a driver by configuring so that an operation of the shift lever switched between the traveling mode and the special moving mode is physically different from an operation of the shift lever switched between the traveling modes or between the special moving modes.

Techniques for diagnosing and disambiguating a bias in one or more axels of a bidirectional four-wheel drive vehicle. In some examples, the diagnostics system may diagnose and disambiguate the bias in the two axles by collecting data related to the movement of the vehicle while the vehicle traverses a zero curvature path in a forward direction. The diagnostics system may then determine a bias in an axle acting as the rear axle based on the collected data. The bias in the axle acting as the front axle may then be determined based on the collected data and the bias in the rear axle.

A hydraulic auxiliary axle steering control system is provided. In detail, there is provided a hydraulic auxiliary axle steering control system that can perform quick, precise, and safe control by changing an auxiliary axle steering control angle in accordance with a vehicle speed to problems with instability of driving, wear of tires, and a turning radius when a vehicle is driven at a low speed.

An apparatus including a command front wheel angle acquirer to acquire a command front wheel angle, a four-wheel target angle calculator to calculate a turning radius, which is a distance from a center of rotation when a vehicle is turning to a center of gravity in a Bicycle model, using the model in a state in which a front wheel angle of the model is simulated as the command front wheel angle, to calculate a rotation angle at the center of gravity of the model on the basis of a ratio of rotation angles of front and rear wheels of the vehicle calculated from a state parameter of the vehicle, and to calculate a target angle of each of the four wheels on the basis of the turning radius and the rotation angle, and a controller to independently control steering of the four wheels using the calculated each target angle.

The invention relates to a method for compensating a stick-slip effect in the case of a recirculating ball steering system (20) having a steering housing (22), in which a steering piston (24) is supported between a first working chamber (34) and a second working chamber (36), wherein the steering piston (24) has a toothed region (26) on the steering-piston outer wall of the steering position, with which toothed region teeth (28) of a segment shaft (30) mesh, the steering piston (24) can he moved along a longitudinal axis X-X, the working chambers (34, 36) are connected to a control valve (39) by means of pressure-medium lines in order to provide steering assistance, the control valve (39) is connected to a processor unit (40), by means of which valves of the control valve (39) can be actuated, and the processor unit (40) is connected to a sensor (42), which determines rotation of the steering column both in a first direction of rotation and in a second, opposite direction of rotation. When a rotational motion of the steering column in a first direction occurs and thereafter the rotational motion in said direction nearly or completely stops, the valves of the control valve (39) are opened by the processor unit (40) in such a way that the pressure in the working chamber (34, 36) of the steering piston (24) facing away from the direction of motion of the steering piston (24) is reduced and immediately thereafter the pressure in the same working chamber (34, 36) is increased again.

Methods, apparatus and systems are provided for steering a vehicle, for example, during autonomous operation. One exemplary method involves operating a locking system associated with a first set of one or more wheels of the vehicle to lock an angle of the wheel(s) and detecting a steering adjustment condition based on the angle during subsequent operation of the vehicle. In response to the steering adjustment condition, the locking system is operated in an intermediate mode, and then thereafter operated to relock the angle of the wheel(s) based on monitoring the angle of the wheel(s) during operation in the intermediate mode.

A method of controlling rear wheel steering in a vehicle including determining a stability state of the vehicle from a plurality of vehicle sensor inputs, determining a target vehicle performance based on the stability state of the vehicle, and determining a target rear angle of rear vehicle wheels based on a difference between a target vehicle characteristic and a model vehicle characteristic, wherein the target vehicle performance promotes agility and stability to a target model at different times based on the stability state of the vehicle.

An apparatus (104) and a method (800) for controlling steering of rear wheels (103) of a vehicle (100) are disclosed. The apparatus (104) comprises a control means (105) configured to receive a first signal indicative of a front wheel steering angle and a second signal indicative of a selected mode selected from at least a first mode and a second mode. The control means is also configured to determine a proposed rear wheel steering angle in dependence on the first signal and the second signal and to provide an output signal configured to cause steering of rear wheels (103) at the proposed rear wheel steering angle.

An apparatus for four-wheel independent steering. The apparatus may include: a rear wheel angle computation unit configured to compute a rear wheel angle (δ.sub.r) resulting by multiplying a front wheel angle (δ.sub.f) by a predetermined front/rear wheel angle ratio (Kss) corresponding to a vehicle speed (V); a gain computation unit configured to compute a gain (A) corresponding to a steering angle acceleration and the vehicle speed and then to output a final rear wheel angle (δ.sub.r) resulting by multiplying the rear wheel angle (δ.sub.r) computed by the rear wheel angle computation unit by the computed gain (A); and a control unit configured to perform rear wheel steering control based on the front wheel angle (δ.sub.f) and the final rear wheel angle (δ.sub.r).

A pedestrian truck (50) steered with a tiller (56) is operable in a first mode where a controllable front wheel (64) is aligned generally parallel with a front-rear centre line of the truck, or a second mode where the wheel is generally perpendicular to the front-rear centre line. A steering controller can operate in either a normal steering mode to steer the rear steerable wheel (52) in the same sense (clockwise or anticlockwise) as the tiller is rotated and in an alternate steering mode to steer the rear steerable wheel in the opposite sense to the rotation of the tiller. A steering mode selector is provided which automatically engages the alternate steering mode when the truck is in the second mode of operation and either (i) the tiller is positioned on the same side of the centre line as the controllable front wheel and the drive direction is such that the tiller leads the truck (FIGS. 12-14), or (ii) the tiller is positioned on the same side of the centre line as the castor front wheel (58) and the drive direction is such that the tiller trails the truck (FIGS. 4, 5).