A technique for inversely identifying joint stiffnesses of robot arms via two-way TubeNets

IF 1.1 4区工程技术 Q3 ENGINEERING, MULTIDISCIPLINARY

Inverse Problems in Science and Engineering Pub Date : 2021-09-02 DOI:10.1080/17415977.2021.1967344

Shuyong Duan, Li Wang, Fang Wang, Xu Han, Guirong Liu

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引用次数: 1

Abstract

Joint stiffnesses of robot arms play a critical role in the control of the posture and movement of the arm tip. This work develops a systematic approach for inverse real-time quantitative identification of the stiffnesses of joints for robotic arms using the TubeNet proposed by Liu. To start with, a finite element (FE) model for a six-axis tandem robot arm is established. Experiments are then conducted to measure the first few lowest natural frequencies of the robot arm to be compared with numerical results for the validation of the FE model. Using the validated FEM model, sensitivity analyses of the joint stiffnesses to the natural frequencies are carried out to ensure sufficient sensitivity for inverse analyses and a neural network data set is established. The selection of appropriate TubeNet layers and activation functions is exposited. Subsequently, the direct-weights-inversion (DWI) formulae for the TubeNet is adopted to inversely compute the joint stiffnesses explicitly in real time. The predicated joint stiffness using the currently proposed DWI formulae of the TubeNet is accurate with the maximum root-mean-square of test errors less than 0.0020 N·m/rad.

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基于双向管阵的机械臂关节刚度反识别技术

机械臂的关节刚度对机械臂末端的姿态和运动的控制起着至关重要的作用。本工作开发了一种系统的方法，利用Liu提出的TubeNet对机械臂关节刚度进行逆实时定量识别。首先，建立了六轴串联机械臂的有限元模型。然后进行实验，测量机器人手臂的前几个最低固有频率，并与数值结果进行比较，以验证有限元模型。利用验证的有限元模型，进行了关节刚度对固有频率的敏感性分析，以保证反分析的灵敏度，并建立了神经网络数据集。介绍了如何选择合适的TubeNet层和激活函数。随后，采用TubeNet的直接权值反演(DWI)公式，实时显式反求节点刚度。使用目前提出的TubeNet DWI公式预测关节刚度是准确的，测试误差的最大均方根小于0.0020 N·m/rad。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Inverse Problems in Science and Engineering 工程技术-工程：综合

自引率

0.00%

发文量

审稿时长

6 months

期刊介绍： Inverse Problems in Science and Engineering provides an international forum for the discussion of conceptual ideas and methods for the practical solution of applied inverse problems. The Journal aims to address the needs of practising engineers, mathematicians and researchers and to serve as a focal point for the quick communication of ideas. Papers must provide several non-trivial examples of practical applications. Multidisciplinary applied papers are particularly welcome. Topics include: -Shape design: determination of shape, size and location of domains (shape identification or optimization in acoustics, aerodynamics, electromagnets, etc; detection of voids and cracks). -Material properties: determination of physical properties of media. -Boundary values/initial values: identification of the proper boundary conditions and/or initial conditions (tomographic problems involving X-rays, ultrasonics, optics, thermal sources etc; determination of thermal, stress/strain, electromagnetic, fluid flow etc. boundary conditions on inaccessible boundaries; determination of initial chemical composition, etc.). -Forces and sources: determination of the unknown external forces or inputs acting on a domain (structural dynamic modification and reconstruction) and internal concentrated and distributed sources/sinks (sources of heat, noise, electromagnetic radiation, etc.). -Governing equations: inference of analytic forms of partial and/or integral equations governing the variation of measured field quantities.