A Continuous Robust Antiswing Tracking Control Scheme for Underactuated Crane Systems With Experimental Verification

Disturbances and uncertainties are unfavorable elements that always accompany industrial mechatronic systems including cranes. If not fully considered or properly dealt with, they would badly influence the control system performance and degrade the working efficiency. Though traditional sliding mode control (SMC) methods are powerful to address these issues, they are discontinuous and might bring potential damages to the actuating devices. In addition, most existing methods cannot involve such practical constraints as permitted swing amplitudes, maximum velocity, etc. To resolve these problems, we suggest a novel composite antiswing crane control scheme, which involves time-suboptimal analytical trajectory planning and continuous robust tracking control. More precisely, a new analytical suboptimal trajectory planning algorithm is presented, which can generate analytical swing-free smooth trajectories guaranteeing practical constraints. Then, we design a new nonlinear control law to make the crane follow the planned trajectories with continuous control efforts, ensuring stable asymptotic tracking in the presence of perturbations/uncertainties. As far as we know, this is the first crane control scheme that simultaneously achieves state-constrained time-suboptimal trajectory planning and robust control with continuous control efforts. We implement experiments to examine its practical control performance and robustness as well.