| With the extensive coverage of urbanization,railway transportation has been developing towards frequent traffic,high speed and heavy load,which has intensified the formation of diseases such as wave abrasion and fatigue crack on the surface and inside of rail.Many years of practice at home and abroad show that rail grinding maintenance technology can not only improve the service life of rail and reduce operating costs,but also improve the transport stability of the train,which promotes the emergence of a variety of rail grinding equipment.Based on this,this paper implements the use industrial robot technology,a 4-DOF rail grinding robot,focusing on robot polishing work "dislocation"problem,based on the overall dynamics analysis,this paper proposes a Π type gantry structure retrofit scheme,and through the weighted sum of NSGAII algorithm to optimize the structure of main parts and components,Finally,the overall system stiffness is improved,and the operation "dislocation" is greatly reduced,so as to improve the stability of the grinding robot operation,and ensure the grinding accuracy and quality.This paper mainly completes the following research work:Firstly,the overall technical route of rail grinding robot is determined according to the actual grinding demand.Then,the mechanism configuration of the robot was analyzed according to the actual situation,the movement model was established,and the effective working space of the rail grinding robot was studied.The contact rate of the grinding wheel face was 88.6%,which met the requirement of the full coverage of rail grinding at least 70.56%.Finally,the modular design method is adopted to complete the preliminary 3D model design of the grinding robot.Then,the dynamic characteristics of 4-DOF rail grinding robot are analyzed based on virtual prototype technology.The joint kinematics simulation of MATLAB and VREP verifies the running state of each motion axis and whether there is interference between each module in the process of grinding robot operation,and verifies the rationality of grinding robot mechanism design.SW and ANSYS WB carried out rigid-flexible coupling dynamic simulation on the grinding robot,and analyzed the operation performance of the robot when grinding rail.Second,in the overall dynamics modeling of robots and polishing the car,on the basis of introduction of grinding sine wave as incentive disturbance,theoretical analysis of the vibration characteristics of grinding robot,analysis of the grinding robot appear "knife"phenomenon,the basic principles of reasonably come to the robot system stiffness can effectively guarantee the orbit plane wave in grinding capacity.Based on this analysis,this paper deals with the structure of the robot Π type gantry structure modification,and through the weighted sum of NSGAⅡ algorithm to optimize the Π model of main components of gantry,eventually improve the overall system stiffness,polishing operations "let the sword" is from the initial design of 4 mm to 1.42 mm,up to 71.35%of the decline,Thus,the stability of grinding robot operation is improved.Finally,the experimental platform of rail grinding robot is built and the experimental research of grinding is completed.Roughness test,profile quality test,smoothness test and system operation frequency test were carried out before and after grinding the rail.Experimental results show that the optimized rail grinding robot after polishing,got significant improvement on the surface of the rail irregularity degree,all measurement point roughness under Ra6.3,profile GQI values are in more than 80 points,finish homework frequency also avoids the high frequency range,effectively restrain the resonance,the polishing effect is to verify the effectiveness of the model optimization,Ensure the safe and smooth operation of trains.Through the analysis of grinding data,the mapping relationship among grinding quantity,grinding Angle and grinding power is obtained qualitatively,which provides a basis for the compilation of grinding mode. |
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