A four-wheeled vehicle includes: a frame; two front suspension assemblies and two rear suspension assemblies connected to the frame; two front wheels operatively connected to corresponding ones of the two front suspension assemblies; two rear wheels operatively connected to corresponding ones of the two rear suspension assemblies; a motor connected to the frame; a front differential and a rear differential operatively connecting the motor to the two front wheels and the two rear wheels respectively; and a steering system. The steering system includes a front steering assembly for steering the front wheels and a rear steering assembly for steering the rear wheels. The front steering assembly includes a user-operated steering input device. The rear steering assembly includes an actuator operatively connected to the rear wheels and operable to modify a steering angle thereof. The actuator is mounted to the frame and is disposed completely rearward of the rear differential.

A trailer for towing a power vehicle with a towable frame forming an undercarriage chassis and a tandem wheel assembly positioned under the undercarriage chassis. The tandem wheel assembly having a first wheel assembly, a second wheel assembly and an extension assembly moving the second wheel assembly along a longitudinal axis of the chassis between trailing position and self-propelled position, with the first wheel assembly and the second wheel assembly are positioned to support the undercarriage chassis.

A method of controlling a vehicle includes obtaining a linear representation of a vehicle dynamics model that includes actuator dynamics u integrated with vehicle dynamics x. The actuator dynamics u include a road wheel angle at rear wheels δr and a torque Mz. The method also includes obtaining an objective function based on a function of the vehicle dynamics x and the actuator dynamics u and formulating a cost function to minimize the objective function. The actuator dynamics u including the torque Mz are determined for a next time sample based on minimizing the objective function. The vehicle is controlled to implement the torque Mz.

An on-board electronics system of an aerial work platform moves the wheels between a retracted and extended position by pivoting a respective arm. The method comprises the following successive steps: a) orienting each wheel tangentially to the pivoting path of the corresponding arm, b) moving the wheel by pivotally actuating the corresponding arm, and c) reorienting the wheel so as to enable another translation of the aerial work platform. The steps are performed in different orders between the wheels so that at any time at least one of the following conditions is complied with: —the brake system of at least one wheel is active, —at least one wheel is rotated by a motorised drive, —the orientation of the wheels relative to one another prevents any translation of the aerial work platform (1) on the ground as a result of gravitational force.

A method for steering a four-wheeled vehicle includes: determining a front wheel steering angle; determining a responsive low-speed steering angle of the two rear wheels, the responsive low-speed steering angle being (i) negative when the front wheel steering angle is positive, and (ii) positive when the front wheel steering angle is negative; determining a responsive high-speed steering angle of the two rear wheels, the responsive high-speed steering angle being (i) non-negative when the front wheel steering angle is positive, and (ii) non-positive when the front wheel steering angle is negative; determining a responsive rear wheel steering angle being a sum of the responsive low-speed and high-speed steering angles; and controlling a steering actuator to steer the two rear wheels in accordance with the responsive rear wheel steering angle.

A steering axle drive assembly includes a steering axle having opposite ends, a wheel pivotally connected with each steering axle end, and a control mechanism. The wheels are operated by the control mechanism for rotation about a vertical axis and a horizontal axis. When the axle is connected with a vehicle, the control mechanism controls the steering axle wheels independent of other wheels of the vehicle, such as the main drive wheels, to steer and drive the vehicle from an origin in any direction without passing through the origin. Preferably, a motor or linear actuator controls the rotation of the steering axle wheels. The steering axle drive assembly can be further improved by including an angled axle.

The present invention relates to a wheel arm forklift truck (1), preferably as an automated guided vehicle, comprising a front end (10c) having at least, preferably exactly, two steerable drive rollers (11a, 11b); comprising at least one first wheel arm (10a) which extends in a straight line away from the front end (10c) and is fixedly connected to the front end (10c), wherein the first wheel arm (10a) has at least, preferably exactly, one first roller (12a); and comprising at least one first fork arm (15a) which is located above the first wheel arm (10a) in the vertical direction (Z) and is designed to be raised and lowered in the vertical direction (Z). The wheel arm forklift truck (1) is characterized in that the first roller (12a) of the first wheel arm (10a) is steerable through at least 90°.

The invention relates to a load-carrying vehicle part with a first and a second wheel pair (10, 11), which are suspended in a respective bogie element (20) on each side of a frame member (14), a suspension (15) between each bogie element (20) and the frame member (14) on each side of the vehicle part to manipulate the frame member relative to the respective wheel pairs (10, 11), or support the frame member in a springing manner, each suspension (15) comprises a first and a second rocker arm (26A, 26B), wherein the first rocker arm is located in front of the second rocker arm viewed in the normal forward direction of driving of the vehicle part, that each rocker arm (26A, 26B) with its one end is pivotably in a joint (27, 27) in the frame member (14) and with its other end is pivotably in a joint (28, 28) in the bogie element (20) a first spring leg (25A) and a second spring leg (25B), wherein each spring leg with its one end (30) is articulately fastened to the frame member (14) and with its other end (31) is articulately fastened in a rocker arm (26A, 26B), a motion conversion arrangement (29) capable of converting a rotary motion in a joint (27, 28) for one of the rocker arms (26A, 26B) to a forward and backward translation motion.

A method for steering a gantry crane having wheel assemblies includes the steps of: initiating movement of the gantry crane; and rotating the wheel assemblies wherein the front wheel assemblies rotate in a first rotational direction and the rear wheel assemblies rotate in a second rotational direction. The first rotational direction is opposite to the second rotational direction. First side wheel assemblies rotate at a first rotational speed and second side wheel assemblies rotate at a second rotational speed, such that the gantry crane moves from a linear path to an arcuate path with a turning radius decreasing to substantially zero for rotation about a central axis.

An extendable axle with wheels on a common centerline preferably includes a base housing, a left axle device, a right axle device, a left extension cylinder and a right extension cylinder. The left axle device slides into a left side of the base housing and the right axle device slides into a right side of the base housing. The left axle device preferably includes a base tube, a steering knuckle, a drive motor and a steering cylinder. The steering knuckle is pivotally engaged with an end of the base tube. The drive motor is retained on the steering knuckle. The steering cylinder pivots the steering knuckle. The right axle device is the left axle device rotated 180 degrees. The left extension cylinder extends the left axle device. The right extension cylinder extends the right axle device. The left drive motor and the right drive motor are on the same centerline.