Experimental Eye-in-hand Calibration for Industrial Mobile Manipulators

A mobile manipulator has a wide range of potential applications because of its extended workspace beyond the stationary manipulator reach, and high flexibility and functionality. However, it is a challenging issue to achieve high accuracy required by industrial manufacturing and production. Therefore, calibration is an imperative process industrial mobile manipulators to move frequently and repeatedly in transport and manufacturing tasks. This study presents an eye-in-hand calibration methodology that can ensure the required high accuracy of the mobile manipulators to complete manufacturing tasks. First, we introduce the eye-in-hand calibration method based on the kinematics and apply the method on an industrial mobile manipulator system developed for experimental testing. Next, we present the image processing implemented on the mobile manipulator to locate the position of experimental objects based on the Region growing algorithm and Depth-first search. Finally, the experiments are conducted to validate the proposed calibration technique using the industrial mobile manipulator locating the position of pins as a case study. This proposed calibration method makes the mobile manipulator capable of working in manufacturing factories with high accuracy and low calibration cost.