Most vehicle transmission systems control the ratio between engine speed and wheel speed using a fixed number of metal gears; the Continuously Variable Transmission (CVT) in currently available vehicles utilize a pair of variable-diameter pulleys connected by a belt or chain that can produce an infinite number of engine/wheel speed ratios for improve fuel consumption, drivability effectively, a...

The next round of planetary missions will require increased autonomy to enable exploration rovers to travel great distances with limited aid from a human operator. For autonomous operations at this scale, localization and terrain modeling become key aspects of onboard rover functionality. Previous Mars rover missions have relied on odometric sensors such as wheel encoders and inertial measureme...

Wheeled mobile robots (WMRs) have a numerous applications and planetary of exploration tasks, all of which require building the suitable dynamic model of the robot. Also, the optimal control model that is intended to guide the robot to accomplish its mission is of a significant need. In addition, it is a certain that achieving a success in the robot controller mission requires an accurate estim...

Six-wheel drive (6WD) articulated dump truck has excellent passing ability and high productivity, but its stability should be improved. A dynamic model of 6WD articulated vehicle with 3 degree-of-freedom (DOF) is established. With the control variables of yaw velocity and side-slip angle at mass center of front body, a feedfoward-feedback control system is designed by linear quadratic regulator...

In this work we study steady-state cornering conditions for a single-track vehicle model without imposing restrictive (i.e., linearized) conditions on the tire slip. For each steadystate cornering condition we calculate the corresponding tire friction forces at the front and rear tires, as well as the required front steering angle and front and rear wheel slip ratios, to maintain constant veloc...

This paper addresses the problem of closing the loop from perception to action selection for unmanned ground vehicles, with a focus on navigating slopes. A new non-parametric learning technique is presented to generate a mobility representation where maximum feasible speed is used as a criterion to classify the world. The inputs to the algorithm are terrain gradients derived from an elevation m...

A common mobile robot design consists of three ‘omniwheels’ arranged at the vertices of an equilateral triangle, with wheel axles aligned with the rays from the center of the triangle to each wheel. Omniwheels, like standard wheels, are driven by the motors in a direction perpendicular to the wheel axle, but unlike standard wheels, can slip in a direction parallel to the axle. Unlike a steered ...

The Mecanum wheel was designed in Sweden in 1975. Using four of these wheels provides omni-directional movement for a vehicle without needing a conventional steering system (Muir & Neumann, 1990; Dickerson & Lapin, 1991; Braunl, 1999; Navy, USA, 2002 and Lunze & Schmid, 2002). The wheel itself consists of a hub carrying a number of free moving rollers angled at 45° about the hub's circumference...

This paper investigates kinetic behavior of a planetary rover with attention to tire-soil traction mechanics and articulated body dynamics, and thereby study the control when the rover travels over natural rough terrain. Experiments are carried out with a rover test bed to observe the physical phenomena of soils and to model the traction mechanics, using the tire slip ratio as a state variable....

Most fielded wheeled mobile robots (WMRs) today use basic 2D kinematic motion models in their planning, control, and estimation systems. On uneven or low traction terrain, or during aggressive maneuvers, higher fidelity models are required which account for suspension articulations, wheel slip, and liftoff. In this paper we present a simple, algorithmic method to construct 3D kinematic models f...