Research On Multi-robot Cooperation For Nuclear Radiation Environment Detection

With the widespread application of nuclear technology,nuclear accidents also occur frequently,and each time bring huge losses to society.Therefore,the detection of nuclear radiation environment is of great value to guide the subsequent nuclear accident handling.By using robots for nuclear radiation environment detection tasks,workers can be protected from the effects of nuclear radiation damage.However,the design of the robot often has a threshold of radiation dose that can withstand.It cannot work in a nuclear radiation environment for a long time.In addition,the single robot has poor fault tolerance during the detection process.If a fault occurs,all subsequent tasks will be affected..The multi-robot collaborative work method can improve the efficiency of environment detection and improve the fault tolerance of the system.Based on the actual needs of "Key Technology Research on Nuclear Emergency Disposal Robots",this paper studies how to realize the detection of nuclear radiation environment by multi-robot cooperation.Firstly,the multi-robot collaborative map construction is realized through the method of map merging to improve the efficiency of environment detection.The Cartographer algorithm based on graph optimization theory is used to construct the local map of a single robot to ensure the accuracy of the local map.Afterwards,in order to ensure the real-time nature of the construction of multi-robot collaborative maps,a method based on ORB feature points was used to register the grid map.During the registration process,the rough matching between the feature points was first performed through the Hamming distance,and then in order to reduce false matches The influence of the points on the final solution of the transformation relationship between the grid maps is to remove the mismatched point pairs in the rough matching step through the random sampling consistency algorithm(RANSAC)method to ensure the accuracy of the final global map.Secondly,the implementation principles of the current mainstream multi-robot formation design methods are explained,and the motion model of the differential wheeled robot is deduced in detail.To ensure that the multi-robot can move in an orderly environment,the pilot-follower method is selected.Perform formation design.Through the typical triangle formation,the kinematics models of the leader and the follower are analyzed in the formation process.Based on this,the formation error model is established,and the motion controller of the follower robot is designed on this basis.Then combine the multi-robot formation with the actual nuclear radiation environment detection task,and combine the different amounts of radiation detected by the robots in different positions during the formation process to guide the formation to move to the high-radiation area.And through the radiation data detected during the formation process,the position of the radioactive source is estimated using the Markov Monta Carlo method(MCMC).Finally,the method proposed in this paper is tested and verified through experiments.The results prove that the multi-robot collaborative map construction method proposed in this paper can achieve a better collaborative map construction effect.At the same time,the independent formation method can also maintain high stability during the operation,and can estimate the position of the radioactive source through the MCMC method through the radiation information detected during the formation process.