Development and control of robotic arms for the Naval Postgraduate School Planar Autonomous Docking Simulator (NPADS)

Abstract

This thesis encompasses the development of two robotic arms for integration onto the Naval Postgraduate School (NPS) Planar Autonomous Docking Simulator (NPADS) servicing vehicle. This research effort involved support structure design, fabrication, and construction, off-the-shelf motion control hardware integration, and control algorithm development and testing. The NPADS system is being built as a test platform for spacecraft docking and capture mechanisms designed for autonomous rendezvous and servicing missions. As with the servicing vehicle, the robotic arms utilize a floatation system on an air-bearing granite table to provide a two-dimensional, drag-free environment. DC brushless servo motors serve as shoulder, elbow, and wrist joints allowing planar motion of the two-link arms. A National Instruments (NI) PXI computer and Motion Control card provide system processing and the software to hardware interface. The NI LabVIEW software suite enabled development of manual control code and autonomous control subroutines compatible with the control software of the NPADS main body. A single, wrist-mounted CCD bullet camera provides visual target acquisition for the robotic arm control system. Testing and analysis were completed in the NPS Satellite Servicing Laboratory on a table-based test harness to facilitate initial design iteration.