A disturbance observer for robotic assembly of odd form electronic components

The success of robotic assembly for odd form electronic components depends heavily on the ability to monitor and control the insertion force. For this purpose, a joint torque disturbance observer for a SCARA robot is proposed to estimate the external reaction force due to component mis-insertion. Based on the internal model control (IMC) concept, this observer is simple in structure. It is in the form of an integral controller and only requires measurements of joint position and velocity signals. The observed perturbation signal includes the effects due to parametric mismatches as well as external disturbance. Careful trajectory planning and detailed friction modelling are performed to enhance accuracy of the deduced reaction force. Implementation on the SCARA robot for PCB component insertion demonstrated the performance of the proposed disturbance observer