| Trackless rubber-tyred vehicle is one of the important equipment forms of auxiliary transportation system in coal mine.It has comprehensive models,wide uses and strong flexibility.However,the complicated underground working conditions lead to the low efficiency and frequent accidents of the manually-driven trackless rubber-tyred vehicle.With the rapid development of China’s intelligent mine construction process,the auxiliary transportation system has become one of the weaknesses of mine intelligent development.Research on driverless trackless rubber-tyred vehicles can reduce the incidence of accidents and realize mine reduction and efficiency improvement.On the other hand,it can also accelerate the construction of intelligent mine.At present,the road driverless technology is becoming more and more mature,but the research on underground driverless technology is still in its infancy.This paper takes the driverless rubber-tyred vehicle as the research object,and carries out its path planning and path tracking research.The research results have theoretical significance and practical value for guiding the driverless design of the trackless rubber-tyred vehicle.Firstly,the underground transportation conditions and driving rules of the trackless rubber-tyred vehicle were analyzed,and based on this,the meeting strategies of the trackless rubber-tyred vehicle in three meeting scenarios,including single-lane roadway,double-lane roadway and cross roadway,had been formulated.Secondly,the paper analyzed the demand of path planning for driverless trackless rubber-tyred vehicle,and chose the A* algorithm for the global path planning of the driverless trackless rubber-tyred vehicle,aiming at the problem of multiple search nodes and unsmooth path in A* algorithm,it used exponential function weighting method and cubic spline interpolation method to improve it respectively,and the simulation results showed that the search efficiency of the improved A* algorithm is improved and the path planned by improved A* algorithm is smoother,the improved A* algorithm was used to simulate the path planning of the trackless rubber-tyred vehicle when changing the roadway underground.Thirdly,the artificial potential field algorithm was selected for the local path planning of the trackless rubber-tyred vehicle,and the escape force and repulsion correction factors were introduced to solve the local optimal solution and the target unreachable problem of the artificial potential field algorithm,and the relative velocity repulsion potential field of moving obstacles was established.The improved artificial potential field algorithm was used to simulate the path planning of the trackless rubber-tyred in three meeting scenarios,and the meeting strategies were preliminary verified.The scene of the combination of dynamic and static obstacles of trackless rubber-tyred vehicle in complex working conditions was simulated.Then,based on the model predictive control algorithm and the dynamics model of the trackless rubber-tyred vehicle,the LTV-MPC path tracking controller was established,the co-simulation model was established based on Car Sim and Simulink,the path planned by the improved A* algorithm and the double lane change were taken as the reference path,and two simulation conditions were set according to the driving rules of the trackless rubber-tyred vehicle,and the co-simulation test was carried out,the results showed that the deviation of the path is not more than ± 0.12 m and the yaw rate is not more than ± 0.08rad/s under the two conditions.It indicated that LTV-MPC path tracking controller has a stable path tracking performance when the speed of trackless rubber-tyred vehicle changes during turning and obstacle avoidance.Finally,the test model vehicle of driverless rubber-tyred vehicle based on ROS was builted,and the simulation roadway was builted according to the scale of8:1.The path planning of trackless rubber-tyred vehicle without obstacles and the path planning of meeting and avoiding obstacles were simulated.The results showed that the improved A* algorithm and artificial potential field algorithm used in this paper can meet the underground path planning needs of the trackless rubber-tyred vehicle.Furthermore,the planned path was tracked,and the path tracking error of the test model vehicle is less than 0 ± 0.036 m at low speed.Through the above research,this paper explored the meeting strategies,path planning algorithm and path tracking algorithm of the driverless rubber-tyred vehicle which conforms to the underground working conditions,which lays a theoretical and technical support for the design of the driverless rubber-tyred vehicle.There are 83 figures,11 tables and 105 references in this thesis. |
