基于并联机构的立柱试验加载装置运动与力传递性能分析

Analysis of Motion and Force Transmission Performance of Column Test Loading Device Based on Parallel Mechanism

针对目前立柱试验台加载装置力传递差、承载力低、运动形式单一的问题,通过对新国标GB25974.2试验内容的分析,提出了一种以并联机构为主体结构的“2T+1T2R”串并混联加载装置。其中以RPU-UPU-PU并联机构作为加载装置的主体结构,借助T&T角与螺旋理论建立起该并联机构的输入传递指数、输出传递指数与局部传递指数的数学模型;利用Matlab绘制出RPU-UPU-PU并联机构的性能图谱。结果证明了所提出的1T2R并联机构具备新国标试验所需的运动姿态与力传递性能,可作为立柱试验加载装置的执行机构,并且偏置后的末端执行器具有更好的定向能力。

A“2T+1T2R”series parallel hybrid loading device with parallel mechanism as the main structure is proposed based on the analysis of the test content of the new national standard GB25974.2,in response to the problems of poor force transmission,low bearing capacity and single motion form of the current column test bench loading device.The RPU-UPU-PU parallel mechanism is used as the main structure of the loading device,and a mathematical model of the input transfer index,output transfer index,and local transfer index of the parallel mechanism is established using T&T angle and screw theory.The performance graph of the RPU-UPU-PU parallel mechanism is drawn using Matlab.The results have proven that the proposed 1T2R parallel mechanism has the required motion posture and force transfer performance for the new national standard test,and can be used as an actuator for the column test loading device.Moreover,the offset end effector has better directional ability.