摘要
火电厂灰库内壁粉尘粘壁、板结、搭桥等现象严重影响火电机组的安全运营,因此须对灰库内壁积灰进行定期全域清理。针对现有灰库清理机器人作业区间有限及因机械臂伸缩比不足、刚度不大导致的清理效果不佳等问题,通过设计引入往复绳排驱动机构和多级嵌套箱型臂体,设计了大刚度、伸缩比为1∶7的机械臂整体结构,研制出一款面向灰库内壁全方位清理的高效作业机器人。基于机械臂级联臂体本征结构和内外耦合作用力系深度分析,结合Castigliano第二定理和线弹性原理,建立了在复杂交变载荷作用下变长度机械臂整体刚度模型。综合考虑在极端工况下机械臂应力分布特征,通过周期性拓扑优化低应力区各离散子域孔洞形状,提出了在严苛质量约束下机械臂全域刚度优化方法。机械臂性能仿真和测试实验表明:优化后机械臂质量大幅减小,且具备理想的伸缩区间和刚度特性;机械臂末端偏移量的测试值与仿真值存在一定偏差,系机械臂加工和装配误差所致。研究结果为灰库清理机器人的结构设计和刚度优化提供了重要参考。
The phenomena of dust sticking, hardening and bridging on the inner wall of ash silo in thermal power plant seriously affect the safe operation of thermal power units, so it is necessary to clean the ash on the inner wall of ash silo regularly. In view of the limited working range of the existing ash silo cleaning robot and the poor cleaning effect caused by the insufficient telescopic ratio and low stiffness of its mechanical arms, reciprocating rope row drive mechanism and multi-level nested boxtype arm body was introduced into the design of the overall structure of the mechanical arm with large stiffness and telescopic ratio of 1: 7. Therefore, an efficient working robot for the all-round cleaning of the inner wall of the ash silo was developed. Based on the depth analysis of the intrinsic structure of the cascade arm and the internal and external coupling force system of the mechanical arm combined with Castigliano’s second theorem and the principle of linear elasticity, an overall stiffness model of the variable length mechanical arm under complex alternating loads was established. Considering the stress distribution characteristics of the mechanical arm under extreme working conditions, through the periodic topology optimization of hole shape of each discrete sub region in the low stress region, a global stiffness optimization method of the mechanical arm under severe mass constraint was proposed.The performance simulation and test results showed that the mass of the mechanical arm was greatly reduced after optimization, and the mechanical arm had ideal telescopic interval and stiffness characteristics. There was a certain deviation between the simulation value and test value of the end offset of the mechanical arm, which was caused by the machining and assembly errors of the mechanical arm. The research results provide an important reference for the structural design and stiffness optimization of ash silo cleaning robot.
作者
张嘉宁
张明路
李满宏
张坦
ZHANG Jia-ning;ZHANG Ming-lu;LI Man-hong;ZHANG Tan(School of Mechanical Engineering,Hebei University of Technology,Tianjin 300401,China)
出处
《工程设计学报》
CSCD
北大核心
2022年第4期430-437,共8页
Chinese Journal of Engineering Design
基金
国家重点研发计划资助项目(2018YFB1309401)。
关键词
伸缩机械臂
结构设计
刚度优化
灰库清理
telescopic mechanical arm
structural design
stiffness optimization
ash silo cleaning
