| The coal mine rescue robot can replace the rescue personnel to enter the mine site for environmental detection and personnel search and rescue,which is of great significance for improving the rescue efficiency and reducing the casualties of the ambulance crew.However,due to the complexity of the post-disaster environment in coal mines,the application of coal mine rescue robots is still not ideal,and all aspects of robotics technology have yet to be broken.Among these,walking ability determines whether the robot can walk smoothly to the disaster area.So,it is very important and urgent to study the related technology of the walking system of the mine rescue robot.However,due to the particularity of coal mine rescue robots,the research on its walking technology must also take into account the explosion-proof design.Only the walking system that satisfies both the walking and explosion-proof requirements can be truly used in coal mine rescue robots.However,explosion-proof design and the walking performance influence each other and restrict each other.How to balance the contradiction between the two aspects,so that the robot walking system not only has good walking ability,but also meets the requirements of explosion-proof performance is the focus and difficulty of this study.In order to put forward the reasonable design requirements for coal mine rescue robots,an in-depth study of the environmental characteristics of coal mines was conducted.Firstly,the working principle of the coal mine rescue robot was described.Based on this principle,the post-disaster environment faced by the robot was analyzed in depth.Five characteristics of the post-disaster environment were proposed,and the structural features of the underground unstructured terrain were extracted.Secondly,according to the results of the environmental analysis,the performance requirements of eight aspects of the robot were proposed,and quantitative indicators for the requirements related to the walking system were emphatically formulated.Finally,the current explosion-proof method was studied,and the iMPact of explosion-proof technology on the performance requirements such as walking was analyzed.Based on the analysis results,the basic design principles of the walking system were proposed.In order to make the walking system suitable for coal mine rescue robots,a performance evaluation index system for tracked walking systems was established.Firstly,from the perspective of actual rescue needs,the performance evaluation index of the walking system of a coal mine rescue robot including four first-level indicators and six secondary indicators was established,and the commonly used comprehensive evaluation methods were analyzed based on the characteristics of the evaluation indicators.Secondly,mathematical models of different performance indicators of five kinds of crawler walking systems were established for the quantitative calculation of indicators to improve the objectivity of the evaluation results.Finally,based on the evaluation index system and performance index calculation results,the five crawler walking systems were evaluated using the network analysis method,and the angle-type tracked walking system was selected as the walking system of the multi-drive coal mine rescue robot.In order to minimize the walking resistance of the walking system to increase the cruising range of the robot,mechanical behavior between the crawler chassis and the ground was studied,and an optimization equation for the parameters of the tracked chassis was established.Firstly,the robot's basic movement turning behavior was used as a physical model,a crawler chassis-ground mechanics model including track and ground frictional resistance and track bulldozing resistance was established.Based on the mechanical model,a track chassis parameter optimization equation was proposed.Secondly,soil mechanics tests were conducted in nine groups of typical coal slime soil to obtain downhole slime soil parameters.Finally,based on the crawler chassis optimization equation and the parameters of slime and soil,the multi-drive coal mine rescue robot crawler chassis' macroparameters were optimized.At the same time,the tracks detailed parameters were also calculated to prevent crawler shedding.In order to reduce the impact of explosion-proof design and increase the walking performance of the crawler chassis,a lightweight design study was conducted on the explosion-proof cabinet.Firstly,the problem of uniform load on the wall of the cabinet was analyzed,and a simple calculation method for the maximum stress of the stiffened wall was proposed.Based on this,a lightweight design equation for the explosion-proof cabinet was established.Secondly,an optimization calculation of the explosion-proof cabinet was carried out based on the design equation.Then the optimal results were solved and a prototype based on the results was tested.Finally,an in-depth analysis of the optimization results was conducted,and the multi-chamber self-reinforced structure and the minimum mass conditions of the explosion-proof cabinet were proposed.In order to reduce the impact of the ground excitation on the robot,the crawler chassis suspension system was studied.First,the existing crawler suspension system was analyzed,and the inclined-angle passive suspension system was selected as the suspension system of the robot.Second,in order to make the selected suspension system have a good obstacle avoidance effect,a dynamic model of the suspension system was established,and the stiffness and damping parameters of the suspension system were optimized based on the dynamic model.Then,the effect of rubber track on ground excitation was studied and the filter effect of track was analyzed.Finally,the simulation analysis and field test of the final crawler chassis vibration reduction effect were carried out.The results showed that the crawler chassis had a good vibration avoidance effect.In order to make the walking system have good dynamic performance,a multi-drive working system was proposed and an adaptive control method was established.Firstly,the iMPact of explosion-proof design on the walking system was further analyzed from the specific data and design theory.Based on the analysis results,a multi-drive cooperative working mode was proposed to meet the double requirements of the robot on speed and torque.Secondly,a two-way clutch based on gravity was developed to realize the mutual conversion between different working modes.Again,in order to solve the problem of switching the working modes,a method of recognizing the road condition by sensing the current of each drive motor was proposed.Finally,simulation analysis,bench tests and prototype field tests were carried out and the tests' results were analyzed.In order to test whether the multi-drive coal mine rescue robot meets the application requirements,a comprehensive robotic experimental study was conducted.Firstly,based on the downhole environment characteristics,seven kinds of robots' walking performance testing platforms including the endurance,braking and heating test platforms were developed,and the individual walking performances of the robot were tested on those test platforms,and the test data were analyzed.Secondly,the comprehensive walking tests were carried out indoors and outdoors,including long-range climbing ability,wading ability,and unstructured terrain adaptability.Finally,field applications were carried out in a coal mine and the National Mine Emergency Rescue Center.Various test results have shown that the multi-drive coal mine rescure robot,in particular the walking system performance,can meet application requirements.After the above research,the multi-drive coal mine rescue robot walking system satisfies the dual requirements of walking and explosion-proof.The coal mine rescue robot based on the multi-drive walking system has obtained the national coal mine safety sign certificate and explosion-proof certificate. |
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