An improved parameter identification method of redundant manipulator

Shi-Ping Liu,Yan Fu,Zi-Yan Ma,Jun-Feng Cao,Jin-Liang Chen,Shi-Qi Li

doi:10.1177/17298814211002118

Abstract

To achieve more accurate simulation and control in the use of the manipulator, it is necessary to establish an accurate dynamic model of the redundant manipulator. The research of this article focuses on the dynamic parameter identification method of the redundant manipulator. In the study, the spinor theory is applied to the Newton–Euler dynamic equation, the Coulomb + viscous friction model is adopted, and the minimum parameter set is obtained by linearization derivation. The parameter identification of the manipulator is realized using the method of offline identification of the measured current, and the coefficient of the excitation trajectory is optimized using the nonlinear optimization function. Finally, the parameter set with high accuracy is obtained, and the motion trajectory of each joint can be obtained. The scheme has high accuracy and can meet the needs of practical application. To verify the accuracy and reliability of this method, we have carried out experiments on a service robot “Walker” and obtained the desired results.

Highlights

The identification of the dynamic parameters of the manipulator mainly involves the methods of estimating structural, inertial, and friction parameters, which are the basis of the research on the manipulator
From the perspective of determining dynamic parameters, existing research on the identification of dynamic parameters is divided into online identification and offline identification, while in terms of torque measurement, it is divided into current measurement identification and torque
The larger the condition number of the matrix is, the more sensitive the matrix calculation is to small disturbance, that is, in the dynamic parameter identification, the larger the condition number of W matrix, the smaller error of joint torque measurement ! will be, which will lead to the inaccurate identification of dynamic parameters

Summary

Introduction

The identification of the dynamic parameters of the manipulator mainly involves the methods of estimating structural, inertial, and friction parameters, which are the basis of the research on the manipulator. Liu et al.[22] proposed to identify inertial parameters based on force measurement and obtained the dynamic parameters of the manipulator through calculation. In the identification of the dynamic parameters of the manipulator, the structural parameters and inertial parameters of the joints need to be considered while considering the friction model. Since some parameters have no effect on robot dynamics, other parameters show linear proportional relationship, matrix HS is listed as zero, correlation is listed as linear, so HS is a singular matrix with multiple solutions To solve this problem, the parameters are usually eliminated and recombined into the basic parameter vector b, which is expressed as b 1⁄4 db þ Kddd (13). B^ is the required minimum parameter set

Introduction of experiment hardware

Design and optimization of excitation trajectory

Conclusions