Most assembly tasks in industry require the manipulator end effectors to come into contact with the work piece. Hence force sensing and feedback can be used to ensure contact between two mating parts, and can be used to monitor the forces of interaction to ensure that they are within a safe limit. As demand for advanced contact control increases, a growth of interest in force regulation and impact control has resulted....[ Read more ]

Most assembly tasks in industry require the manipulator end effectors to come into contact with the work piece. Hence force sensing and feedback can be used to ensure contact between two mating parts, and can be used to monitor the forces of interaction to ensure that they are within a safe limit. As demand for advanced contact control increases, a growth of interest in force regulation and impact control has resulted.

Force control technology has not been commonly practiced in the current generation of die and wire bonding machines. To regulate the impact force, one has to rely on an accurate position control and low bonding movement. This limits the performance and productivity of the bonding machines. To improve this situation, a force feedback control becomes necessary.

Force feedback control has several advantages over the accurate position control in most die and bonding machines:

(1) Regulation of impact force with even wide variations in die size.

(2) Maintenance of constant contact forces to any desirable levels after impact.

(3) Substantially reducing oscillation period to enhance the bonding rate.

To verify and analysis the force control technology, force control has been implemented on an industrial vertical wire bonding machine.

This study has investigated different force feedback controllers. These included linear controller, adaptive controller and hybrid position-force controller. The results of the experiments show that force control can stabilize the end-effectors more effective than pure position control.