尖轨端面复杂廓形机器人铣削轨迹规划方法  

Trajectory Planning for Robot Milling of Complex Profiles on Switch Rail Tip Surface

作　　者：吴志伟 樊文刚[1,2] 李江 张峻瑞[1,2] 吴昌昕 刘弋 WU Zhiwei;FAN Wengang;LI Jiang;ZHANG Junrui;WU Changxin;LIU Yi(School of Mechanical and Electronic Control Engineering,Beijing Jiaotong University,Beijing 100044,China;Key Laboratory of Vehicle Advanced Manufacturing,Measuring and Control Technology,Ministry of Education,Beijing Jiaotong University,Beijing 100044,China)

机构地区：[1]北京交通大学机械与电子控制工程学院,北京100044 [2]北京交通大学载运工具先进制造与测控技术教育部重点实验室,北京100044

出　　处：《中国铁道科学》2024年第3期12-25,共14页China Railway Science

基　　金：中央高校基本科研业务费重点资助项目(2023JBZY020);北京交通大学科技成果转化培育项目(M21ZZ200010)。

摘　　要：铁路道岔尖轨数控成型铣削后的打磨抛光目前普遍由人工完成,存在效率低、质量一致性差和漏打磨等问题,难以满足尖轨高效高质加工需求。而将工业机器人铣削技术应用到打磨抛光工序中虽可提升尖轨制造自动化水平,但尖轨端面廓形的复杂多变以及机器人存在的弱刚性又导致其加工轨迹平滑度难以得到保障。为此,需要对尖轨端面复杂廓形机器人铣削轨迹规划方法进行创新。首先,基于MD-H参数法建立机器人运动学模型并分析其运动特性;然后,采用三次NURBS曲线对尖轨端面廓形进行参数化描述,以铣削作业法向刚度性能指标作为优化目标,建立轨迹点姿态优化模型;同时,考虑机器人关节连续性约束,建立机器人铣削轨迹姿态规划模型;在此基础上,基于S型曲线算法实现机器人铣削速度规划;最后,通过仿真和试验进行验证。结果表明:该方法能够有效控制机器人的运动轨迹,解决了外凸夹角区域的“过切”和“跳刀”问题,加工后尖轨端面廓形更为平滑,能满足尖轨制造要求。The grinding and polishing of the switch rail after CNC shaping and milling in railway turnout is currently conducted manually,resulting in issues such as low efficiency,poor quality consistency,and missed grinding,which hinder meeting the requirements for efficient and high-quality processing of switch rail.While the integration of industrial robot milling technology into the grinding and polishing process can enhance the automation level of switch rail manufacturing,the complexity and variability of the switch rail tip profile and the weak rigidity of robots pose challenges in ensuring the smoothness of the machining trajectory.Therefore,it is imperative to innovate the trajectory planning method of the robot with complex profile on switch rail tip surfaces.Firstly,a kinematics model of robot is established based on MD-H parameter method and its motion characteristics are analyzed.Then,the tip profile of the switch rail is parameterized by cubic NURBS curve.An optimization model for trajectory point pose is developed,with the normal stiffness performance index of the milling operation as the optimization objective.Meanwhile,considering the constraints of robot joint continuity,a pose planning model for robot milling trajectory attitude is established.On this basis,the robot’s milling speed is planned using an S-shaped curve algorithm.Finally,simulation and experiments are conducted for verification.The results show that this method can effectively control the trajectory of the robot,address the issue of“over-cutting”and“tool jumping”in the convex-included angle area through the inserted transition curve,and achieve a smoother tip profile of the switch rail after processing,meeting the manufacturing requirements of the switch rail.

关 键 词：铁路道岔 尖轨 工业机器人 铣削技术 轨迹规划 NURBS曲线 

分 类 号：U213.6[交通运输工程—道路与铁道工程]