Pulse Width Modulated Control for the Dynamic Tracking of Wheeled Mobile Robots
This paper considers the control of differentially driven wheeled mobile robots through the use of a dynamic model that includes all the significant uncertainties such as external forces and tire slip in both the lateral and longitudinal directions. The influences of these uncertainties on the robot dynamics are analyzed and the matching condition for Pulse Width Modulated (PWM) control is studied. It is proven that position tracking control using the PWM method is invariant to both the external forces and tire slip. Combined position and orientation tracking control is also invariant if the desired orientation is tangent to the desired path or if the derivative of lateral slip is negligible. A multivariable PWM tracking control algorithm is developed that guarantees robustness to the influences of the uncertainties. Through experiments with a high load wheeled mobile robot developed for automating highway maintenance and construction tasks, the developed control is shown to be highly accurate, globally stable and robust to disturbances.
KeywordsMobile Robot Matching Condition Tracking Control Pulse Width Modulate Variable Structure Control
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