Geometrical Parameter Identification of a Hybrid Redundant Robot by Utilizing Differential Evolution

Y. Wang, H. Wu, and H. Handroos (Finland)


Identification, Calibration, Differential Evolution, Hybridredundant robot


In this paper, a hybrid serial-parallel redundant robot IWR (Intersector Welding Robot) is presented. In practical application, the geometrical errors caused by the manufacturing and assembly processes are inevitable and have to be compensated or suppressed to a certain value to meet the required accuracy of the robot. However, it is still very difficult and even impossible to measure the geometrical errors of the corresponding joints and link lengths after the structure has been assembled. Therefore, calibration and identification of these unknown and unmeasurable parameters are absolutely necessary to improve the systematic accuracy. This paper presents a calibration method for identifying the unknown geometrical error parameters by using Differential Evolution (DE) algorithm. The DE algorithm is able to search all the possible solutions within the solution set and guarantee the fast convergence to the best global solutions. Based on the inverse kinematic error model of the robot, simulation is conducted by introducing random geometric errors and measurement poses which represent the related real physical behaviours. The validity and effectiveness of the DE algorithm for the proposed application is also examined.

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