Design And Dynamic Research Of Search-and-rescue Robot Used In Underground Coal Mine

China is a big coal producer in the world,but it is also a country with frequent mine accidents.With the increase of accidents and disasters occurring in the explosive environ-ment,rescue activities are more and more essential.The situation of coal mine accident is very dangerous.If rescuers rush into the disaster scene,their lives will be threatened seriously.The rescue robot with coal mine explosion-proof function can replace the res-cuers for going into the disaster scene to carry out environmental detection to avoid rescuers'lives being threatened.The environmental detection which includes real-time monitoring of underground concentrations of explosive gases,ambient temperature,sounds and building damage is the main mission of the robot.The information returned by rescue robot can truly reflect the situation of underground accident scene and provide a scientific basis for helping rescuers formulate a rescue plan to improve the efficiency of rescue response and minimize the casualties of rescuers.In the rescue process,the robot is working in a very dangerous explosion environment.The explosion-proof design of the robot has always been a design problem.Although the mine rescue robot has been researched since the 1980s,there is no strictly explosion-proof rescue robot which is approved by the Safety Approval and Certification Center in China.This paper designs and researches the first robot with a strictly explosion-proof manipulator used for clear obstacles,and which is approved by the Safety Approval and Certification Center in ChinaThrough the research and analysis of the general structure and explosion-proof capabil-ity of other coal mine rescue robots,a modularity coal mine rescue robot with explosive-proof electrical box and explosive-proof motor box is designed and researched in this paper,which is easy to repair and maintain in underground coal mine.The explosive-proof electrical box is designed based on the elastic-plastic theory which can reduce the mass of the box designed based on elastic theory.So far,most robots cannot go forward when they are blocked by obstacles.So,manipu-lators are needed in order for robots to finish rescue missions.However,few robots can meet these requirements,because it is difficult to design an explosive-proof manipulator.This paper introduces a method used for designing manipulators which can work in the explo-sive environment.The manipulator adopted in this design method can drive more than three joints,and only uses two motors.One motor is used to supply power for driving joints and the other is used for switching the power among joints.Both of them can be separated with a manipulator and mounted on a robot chassis with an explosive-proof box.In this way,the load capacity and explosion-proof security of manipulators can be improved.The develop-ment of this design method can provide a reference for designers to develop future rescue robots in explosive environmentsThe rescue robot designed in paper adopts the crawler running.Based on the computa-tional terramechanics,a calculation model of the force between the track and the ground is established.The dynamic characteristics of the robot moving on the ground are studied in detail,including the longitudinal tractive force,lateral resistance force and steering torque.In addition,an inclined load-bearing wheel assembly is designed and researched based on the theory of ride comfort to buffer the impact of obstacles on the robot,and the traveling stabil-ity of the robot in the direction perpendicular to the ground is studied.The spring stiffness and damping parameters of load-bearing wheel assembly are determined by the equivalent mechanics model proposed in paper.By designing the front load-bearing wheel assembly that assists the robot to climb over obstacles,the impact force when climbing obstacles is converted into power for climbing obstacles.A flexible communication method combining wireless Wi-Fi and wired optical fiber is designed for robot.A moving control system including semi-autonomous and manual remote-control mode is established for robot remotely controlling in coal mine environment with autonomous anti-collision,overturning protection and track deduction function.The sensor system is designed to collect videos,sounds and 10 kinds of gas environment param-eters of the explosive environment for rescuers to make rescue plan.The relay communica-tion box for communicating with operate control unit by Wi Fi can be released by the linkage mechanism which is driven by the link of CH₄lift-sensor used for detecting the CH₄in coal mine roadway.The coal mine rescue robot proposed in paper is tested in test center for working perfor-mance,finally it obtains the national coal product safety mark.In addition,an experimental study is conducted on the robot in a real mine roadway environment.Furthermore,the robot is trained and tested by rescuers.