Rule-based control of a mobile robot for the push-a-box operation

To make a mobile robot do some meaningful job was the motivation to start the research work described. The authors define the problem and derived the equations of motion for a robot and a pushed box. The authors take the rule-based control scheme as a fundamental tool for control. The authors have analyzed the equations of motion and found that the situation is similar to the problem of an inverted pendulum popular in the usual automatic control theory. In normal situations the stability is more urgent than to follow a trajectory. By this observation the authors have introduced a hierarchical structure in rules. That is, the rules to maintain the angle between the robot and its box small is applied first. Other rules are considered only when the angle is sufficiently small. The authors adopt crisp rules, which means that they divide a given variable into intervals, and in each interval they have different set of rules. The total number of rules used in the experiments is 120