Rigid-flexible coupling dynamic model of a flexible planar parallel robot for modal characteristics research

Lianchao Sheng,Mengbao Fan,Xuefeng Yang,Wei Li,Yuqiao Wang

doi:10.1177/1687814018823469

Lianchao Sheng, Mengbao Fan + Show 3 more

Open Access

https://doi.org/10.1177/1687814018823469

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Abstract

The increasing applications of flexible parallel robots in industrial production have presented the advantages of light weight and high speed, but at the same time, the elastic vibration problem has emerged. By investigating the modal features of flexible parallel robots so as to suppress the elastic vibration, with pinned-pinned as flexible intermediate links boundary conditions, this article analyzes the rigid-flexible coupling dynamic mathematical model of the 3-RRR (3-Rotate-Rotate-Rotate) flexible planar parallel robot with flexible intermediate links. The effect of the extremity concentrated rotation inertia of flexible intermediate links is considered in the mathematical model. Besides, the effect of inertia and coupling force on the dynamic model and the first three-order vibration responses of flexible intermediate links were discussed based on the established model. The corresponding spectrum characteristics were studied using fast Fourier transform. Comparing the frequency characteristics obtained by theoretical model and modal experiment, it was found that the results obtained by the dynamic mathematical model are quite close to the test results. Less dynamic parameters make it convenient to carry out the control program.

Highlights

Compared with the serial robots, parallel robots possess a lot of advantages such as high speed and acceleration, heavy load capacity, low energy consumption, no cumulative error, and precise accuracy, which are widely used in aerospace, precision optical instruments, real-time high-precision measuring instruments, precision machine tools, and other fields.[1,2,3,4]As the society advances, the development of the global mechanical products follow the way of high speed and efficiency as well as light weight with low power consumption
When the flexible parallel robots operate with loads at a high speed, due to the inertia force and other factors, the elastic deformation of the flexible intermediate links (FILs) is prone to occur, resulting in a declining dynamic performance of the robot, the normal work will be affected
The effect of the rotatory inertia caused by FIL ends to the coupling dynamic model and system modal characteristics are investigated based on the established theory model

Summary

Introduction

Compared with the serial robots, parallel robots possess a lot of advantages such as high speed and acceleration, heavy load capacity, low energy consumption, no cumulative error, and precise accuracy, which are widely used in aerospace, precision optical instruments, real-time high-precision measuring instruments, precision machine tools, and other fields.[1,2,3,4]As the society advances, the development of the global mechanical products follow the way of high speed and efficiency as well as light weight with low power consumption. Keywords Flexible parallel robots, assumed mode method, coupling dynamic model, vibration response, spectral characteristics Yu et al.[30] verified the dynamic model of the flexible planar 3-RRR parallel robot through experimental study.

Results

Conclusion