This paper investigates the path tracking problem for an electric vehicle which has four electromechanical wheel systems under normal and faulty conditions. With considering wheel slip constraints and certain actuator faults, a passive fault-tolerant controller based on variable structure control is developed to maintain the system stability and guarantee the acceptable tracking performance. Th...

An approach to estimate the tire{road friction during normal drive using only the wheel slip, that is, the relative diierence in wheel velocities, is presented. The driver can be informed about the maximal friction force and be alarmed for sudden changes. Friction related parameters are estimated using only signals from standard sensors in a modern car, and the physical relation between these p...

A wheeled ground robot was designed and built for better understanding of the challenges involved in utilization of accelerometerbased intelligent tires for mobility improvements. Since robot traction forces depend on the surface type and the friction associated with the tire-road interaction, the measured acceleration signals were used for terrain classification and surface characterization. T...

In this paper, two control approaches are presented for exploration rovers traversing sandy-sloped terrain. One of the proposed controls is a model-based feed-forward control using a characteristic diagram, called a Thrust-cornering characteristic diagram. It consists of various characteristic curves of wheel forces for varied wheel slip conditions. An appropriate steering maneuver for slope tr...

This paper presents analytical models to investigate the steering maneuvers of planetary exploration rovers on loose soil. The models are based on wheel-soil interaction mechanics, or terramechanics, with which the traction and disturbance forces of a wheel are evaluated for various slip conditions. These traction forces are decomposed into the longitudinal and lateral directions of the wheel. ...

This application note focuses on a design based on National Semiconductor’s patented NeuFuz based neural-fuzzy technology to arrive at a slip control scheme implemented on National Semiconductor’s low-cost COP8TM microcontroller. NeuFuz technology allows for the automated generation of a fuzzy logic control engine based on training data. In this case, the training data was taken from the well k...

This paper, proposes a methodology to implement a suitable nonsingular terminal sliding mode controller associated with the output feedback control to achieve a successful trajectory tracking of a non-holonomic wheeled mobile robot in presence of longitudinal and lateral slip accompanied. This implementation offers a relatively faster and high precision tracking performance. We investigate this...

This paper deals with the kinematic analysis of a wheeled mobile robot (WMR) moving on uneven terrain. It is known in literature that a wheeled mobile robot, with a fixed length axle and wheels modeled as thin disk, will undergo slip when it negotiates an uneven terrain. To overcome slip, variable length axle (VLA) has been proposed in literature. In this paper, we model the wheels as a torus a...