Multi-robots Formation Control Based On Null-space-based Method

Multi-robot system is a complex intelligent system and researchers pay more and more attention to it. It is able to finish so much work which single robot is disable to. It has the advantage of high stability, efficiency and low cost etc.. Multi-robot formation is an important problem in the study of multi-robot system and it can improve the coordination and efficiency of multi-robot. The main work of this thesis is to utilize the Null-Space-Based multi-robot control method in the multi-robot formation problem. Main contents are as follows:First, the history and current situation of multi-robot research is analyzed and muti-robot research development is summarized briefly. Regarding the characteristics and requirements of robot soccer competition, a behavior-based multi-robot control method, the Null-Space-Based method, is introduced.Second, on the basis of detailed analysis and research for Null-Space-Based method, regarding the single NuBot soccer robot platform, the kinematic formula in a class of omni-directional motion platform based on Null-Space-Based method is deduced, and the NSB mothod is extended to three-dimension space from the original two-dimension space. The task function of each sub-behavior, by using Null-Space-Based method is deduced to perform integrated multi-task, and a final overall output function is derived. The simulation experiments on NuBot simulation platform show that multi-task coordination works well by using Null-Space-Based method when a single robot need to perform multiple tasks at the same time and the low-level tasks can be implemented at the same time without affecting the quality and effectiveness of the implementation of high-level tasks. Null-Space-Based method can resolve the conflict between multiple tasks very well.Third, on the basis of single robot Null-Space-Based method, the formation problem of several omni-directional motion platforms is studied, and the original centralized system is converted into a distributed system and the theory scope application space of NSB method also is expanded. On the NuBot simulation experiment platform, the simulation experiments of multiple robots formating, maintaining formation as well as avoiding obstacle in formation etc. are performed. The experimental results show that multi-robot formation can be realized well, the formation is very stable, and the original formation can be maintained while resisting the interference from obstacles.Finally, a simple summary on the content of this theis is presented, and the future study on the multi-robot formation also is proposed.