Control Strategies for APACTS Micro-Macro-Manipulator Integration
Richard J. Norcross
The Carderock Division of the Naval Surface Warfare Center is developing the Automated Paint Application, Containment, and Treatment System (APACTS). APACTS will apply anti-corrosive and anti-fouling paints to ship hulls in an environmentally sound manner. To provide accurate motion over very large surfaces, the APACTS motion system employs a self-propelled base carrying a long reach macro-manipulator, which in turn carries a quick response micro-manipulator to maneuver the paint nozzle and containment device. The manipulators run separate but coordinated trajectories whose combination is the path of the paint nozzle. Based on feedback from sensors and the operator's observations, the controller shifts the path to keep the paint nozzle at the appropriate position relative to the surface being painted. The micro- and macro-manipulator trajectories must adapt to the ship hull and ensure the micro-manipulator does not exceed its operating volume. This report compares strategies for correcting the paint nozzle position. These strategies include; direct modification of the macro-manipulator trajectory, modification of the micro-manipulator trajectory during various portions of its trajectory cycle, and alterations to the micro-manipulator trajectory. The experiments discussed in this report show that the best results occurred when the micro-manipulator trajectory shifts immediately upon error detection during the upstroke and the macro-manipulator trajectory modifies to keep the micro-manipulator centered. The results further indicate an extended period on the upstroke prior to painting enhances overall system accuracy.
Control Strategies for APACTS Micro-Macro-Manipulator Integration, NIST Interagency/Internal Report (NISTIR), National Institute of Standards and Technology, Gaithersburg, MD, [online], https://doi.org/10.6028/NIST.IR.6873
(Accessed June 5, 2023)