Predictor Based Control Strategy for Wheeled Mobile Robots Subject to Transport Delay

Abstract

A Smith-type predictor compensator has been proposed for two types of wheeled mobile robots subject to either an input or a bilateral time-delay. Using the exact discrete-time posture kinematic model of the mobile robots, the predictor's structure allows to implement noncausal control laws whose design is based on the delay free system. Numerical simulations show that the mobile robots will track a delayed version of the reference trajectory. Many possible improvements to the proposed prediction-control scheme are possible. As noted by (Michiels and Niculescu, 2007), most of the work regarding the Smith predictor focuses on its robustness and its disturbance rejection characteristics. These issues are definitely relevant in the context of mobile robotics and should therefore be followed closely. For example, an adaptive algorithm that compensates for mismatch in the time-delay model would significantly improve the system's performance. A further extension of this work to robotic manipulators is also a possibility. In this case, issues such as the reflection of the contact and the driving forces has to be considered.