A DISTURBANCE OBSERVER FOR ROBOT MANIPULATORS WITH APPLICATION TO ELECTRONIC COMPONENTS ASSEMBLY

The success of robotic assembly for odd form electronic components dep ends heavily on the ability to monitor and control the insertion force . For this purpose, a joint disturbance observer for robot manipulator s is presented to estimate the reaction force due to component misinse rtion. The derivation is presented in the time domain for a multi-degr ee-of-freedom manipulator without making the SISO linear system assump tion. Based on the Internal Model Control (IMC) concept, this observer is simple in structure. It is in the form of an integral controller a nd only requires measurements of joint position and velocity signals t o be implemented. The observed perturbation signal includes the effect s of model uncertainties as well as reaction force against the environ ment. Careful trajectory planning and detailed friction modeling are p erformed to enhance accuracy of the deduced reaction force. Experiment s conducted on an SCARA robot for the insertion of PCB components demo nstrated the performance of the proposed disturbance observer.