轮式管道机器人过弯动态特性分析
Analysis for Dynamic Characteristics of Wheeled Pipe Robot in Elbow

为了详细地了解管道机器人过弯时的动态特性,设计了一种全驱动轮式管道机器人。基于坐标转换法,分析了机器人过弯时质心与管道中线的相对距离Δx发生变化对机器人运动特性的影响;基于力学虚功原理,分析了机器人过弯时Δx发生变化对机器人受力情况的影响。通过Adams软件对机器人过弯过程中的运动状态和受力情况进行了仿真,经分析发现管道机器人在过弯过程中,Δx先快速增大后略低速减小,在运动特性方面,随着Δx增大,外驱动轮运动速度随之增大,内驱动轮运动速度则有所减小。当内驱动轮速度达到最低时,外驱动轮与内驱动轮的速度之比会发生小幅度波动;在受力情况方面,随着Δx增大,内、外驱动轮与管壁的接触力随之增加,此仿真模型中,在入弯阶段外驱动轮和内驱动轮与管壁接触力大小之比为1.4,出弯阶段此接触力之比约降为0.9。从平稳性角度来看,与入弯和出弯两个阶段相比,过渡阶段在运动和受力上均相对不稳定,故当机器人过弯时,将Δx的变化纳入运动分析方程有利于获得其更加精确的动态特性。
A fully driven wheeled pipe robot is designed to understand the dynamic characteristics of pipe robots over a curve in detail. Influences of the changing distance Δx between the center of mass and the center line of the pipeline on the motion characteristics of the robot are analyzed based on the coordinate transformation method, and the effects of the relative distance on the force on the robot are analyzed based on the principle of mechanical virtual work. The motion state and contact force of the robot are simulated through the ADAMS software. It is found from the analysis that the relative distance increases rapidly at first and then reduces at a lower speed during the cornering process. The motion state has the following characteristic that the speed of the outer drive wheel increases and the speed of the inner drive wheel reduces as Δx increases. When the speed of the inner drive wheel reaches its minimum value, the ratio of the speed of the outer drive wheel to the inner drive wheel has small fluctuation. The contact force between both inner or outer drive wheels and the pipe wall increases as Δx increases. Simulation also shows that the ratio of the contact force between the outer drive wheel and the pipe wall to the contact force between the inner drive wheel and the pipe wall is 1？？4 during entering elbow stage, while this contact force ratio reduces to about 0？？9 during exiting elbow stage. It is found from the standpoint of stability that the transitional period is relatively unstable in both the motion and the stress compared to the two stages of entering and exiting. Therefore, when the cornering process of a pipe robot is analyzed, considering Δx variation in the motion analysis equation will be beneficial to obtain its more accurate dynamic characteristics