Cooperative material handling between industrial manipulators using structural compliance.

摘要

In this dissertation we proposed and successfully implemented cooperative material handling on two STAUBLI RX130 industrial robots, where the sharing of gravitational and inertia load is controlled to maximize the overall load capacity. We adopt a clamped-compliant configuration between the leader and follower robot(s), where the compliance device on the follower robot serves to control force on the directions of gravity and inertia (load share control) at the same time reduces internal force on the non-force-controlled directions. The follower robot trajectory is pre-shaped (through convolving with a notch filter) to carry its share of load at the same time cancel out motion end vibration, which reduces the impact force on the leader robot mechanism.;We also studied the effect of temporal error during cooperative manipulation and proposed a method to synchronize the controller logical timers (within 1 ms) using serial communication. Our proposal of cooperative material handling can be realized either open loop or closed loop. While the open loop approach is fast and easy to implement, the closed loop approach achieves more accurate load sharing therefore maximizes the overall load capacity.;Our proposal offers a feasible and inexpensive solution to the industrial application of cooperative material handling. It can be readily implemented on commercial robot without ANY modification on robot mechanism or knowledge of system dynamics. The structural compliance guarantees minor internal force during the cooperative manipulation. The force control, trajectory pre-shaping and coordination can be all implemented with standard commands (such as ALTER, READ/WRITE) on industrial controllers.;We have demonstrated to achieve a speed of 0.5m/s of cooperative motion—much faster than existent impedance/hybrid control based approaches. We are confident to increase the speed to almost as fast as the robots can move.