Researches And Realization On Multi-Robot Parking Task

This paper takes the multi robots parking task as the goal, studies themulti robots' cooperation mechanism being dealed with. It includes threemain parts of contents, that is, a continuous obstacle avoidance strategyunder multi obstacles environment, multi robots' collision avoidance, andthe strategy of distributing and assigning parking points.The sonar ring structure based obstacle avoidance strategy that hasbeen designed in this paper, mainly aims at the situation in witch therobot meets another obstacle when it's in the state of avoiding obstacle. Akind of direction selection rules based on the avoiding sub-behavior statesis designed, to choose the right avoiding direction, with the cooperationof the current obstacle orientation been detected. And the quadrant basedmethod is proposed, to decide the robot's current action, that is, shouldthe robot go to the goal point directly now, or should it continues itsavoiding action along the former obstacle's side, thus reduce theblindness and repetition of obstacle avoiding actions in great limit.In the collision avoidance strategy of multi robots, a model named"No-Traffic-Light-Crossing" is built. In this model, a Pass-Priorityevaluating function is designed, to decide which of the two robots in themodel will gain the pass priority. Task exigent extend, danger extend, andthe distance from robot to the crossing are three factors of the function,and distance is the dominant factor, mainly reflecting the "first come firstpass" rule. While avoiding, the robot which hasn't gotten the pass prioritymainly select the strategy of adjusting velocity, sometimes acts as leavingthe crossing to avoid, to make sure that the other robot of the model willpass the crossing first, and this strategy simulates and reflects the latenttraffic rules in a certain extent. Digraph is used to describe the avoidancerelation of multi-robot system, and the "dead-lock" problem will besolved through stepwise eliminate the cycles of the digraph.On multi-robot parking experiment, this paper supposes all parkingpoints follow the symmetrical distributing principle. Based on it, thestrategy of assigning parking points to get the "Shortest Total PathLength" is realized using the "Hungary Method" of operational research. A "Benefit Matrix" is formed, taking each length of the outside path ofthe inclosing circle from robots to parking points as the elements. Andthen the best assignment is obtained through the "Hungary Method". Bythe way, this part also discusses a "Shortest System Executing Time"based assigning strategy and a strategy considering the scope of seeableview of inclosing circle.