1. Gardell G. Gefke, Craig R. Carignan, Brian J. Roberts, and J. Corde Lane University of Maryland Space Systems Laboratory http://www.ssl.umd.edu/ Ranger Telerobotic Shuttle Experiment: Status Report Intelligent Systems and Advanced Manufacturing Conference Telemanipulators and Telepresence Technologies VIII 28 October 2001

2. Space Systems Laboratory University of Maryland Ranger Robotics Program: Status Report 2 Space Systems Laboratory 25 years of experience in space systems research A part of the Aerospace Engineering Department at University of Maryland People –4 full time faculty –12 research and technical staff –18 graduate students –28 undergraduate students Facilities –Neutral Buoyancy Research Facility (25 ft deep x 50 ft in diameter) »About 150 tests a year »Only neutral buoyancy facility dedicated to basic research and only one in world located on a university campus »Fabrication capabilities include rapid prototype machine, CNC mill and lathe for prototype and flight hardware –Class 100,000 controlled work area for flight integration Basic tenet is to involve students in every aspect of research

3. Space Systems Laboratory University of Maryland Ranger Robotics Program: Status Report 3 What are the Unknowns in Space Robotics? Ground Control? Capabilities and Limitations? Multi-arm Control and Operations? Flexible Connections to Work Site? Interaction with Non- robot Compatible Interfaces? Effects and Mitigation of Time Delays? Control Station Design? Human Workload Issues? Utility of Interchangeable End Effectors? Manipulator Design? Hazard Detection and Avoidance? Development, Production, and Operating Costs? Ground-based Simulation Technologies?

4. Space Systems Laboratory University of Maryland Ranger Robotics Program: Status Report 4 “Ranger” Class Satellite Servicers Ranger Telerobotic Flight eXperiment (RTFX) –Free-flight satellite servicer designed in 1993; neutral buoyancy vehicle operational since 1995 –Robotic prototype testbed for satellite inspection, maintenance, refueling, and orbit adjustment –Demonstrated robotic tasks in neutral buoyancy »Robotic compatible ORU replacement »Complete end-to-end connect and disconnect of electrical connector »Adaptive control for free-flight operation and station keeping »Two-arm coordinated motion »Coordinated multi-location control »Night operations With potential Shuttle launch opportunity, RTFX evolved into Ranger Telerobotic Shuttle eXperiment in 1996

5. Space Systems Laboratory University of Maryland Ranger Robotics Program: Status Report 5 Demonstration of dexterous robotic on-orbit satellite servicing –Robot attached to a Spacelab pallet within the cargo bay of the orbiter –Task ranging from simple calibration to complex dexterous operations not originally intended for robotic servicing –Uses interchangeable end effectors designed for different tasks –Controlled from orbiter and from the ground A joint project between NASA’s Office of Space Science (Code S) and the University of Maryland Space Systems Laboratory Key team members –UMD - project management, robot, task elements, ground control station –Payload Systems, Inc. - safety, payload integration, flight control station –Veridian - system engineering and integration, environmental testing –NASA/JSC - environmental testing Ranger Telerobotic Shuttle eXperiment (RTSX)

6. Space Systems Laboratory University of Maryland Ranger Robotics Program: Status Report 6 Ranger’s Place in Space Robotics How the Operator Interacts with the Robot How the Robot Interacts with the Worksite

7. Space Systems Laboratory University of Maryland Ranger Robotics Program: Status Report 7 Robot Characteristics Body –Internal: main computers and power distribution –External: end effector storage and anchor for launch restraints Head = 12  cube Four manipulators –Two dexterous manipulators (5.5  in diameter; 48  long) »8 DOF (R-P-R-P-R-P-Y-R) »30 lb of force and 30 ft-lbf of torque at end point –Video manipulator (55  long) »7 DOF (R-P-R-P-R-P-R) »Stereo video camera at distal end –Positioning leg (75  long) »6 DOF (R-P-R-P-R-P) »25 lb of force and 200 ft-lbf of torque; can withstand 250 lbf at full extension while braked ~1500 lbs weight; 14 length from base on SLP to outstretched arm tip

8. Space Systems Laboratory University of Maryland Ranger Robotics Program: Status Report 8 Robot Stowed Configuration

9. Space Systems Laboratory University of Maryland Ranger Robotics Program: Status Report 9 Fiduciary tasks –Static force compliance task (spring plate) –Dynamic force-compliant control over complex trajectory (contour task) –High-precision endpoint control (peg-in-hole task) Task Suite Robotic assistance of EVA –Articulating Portable Foot Restraint setup/tear down EVA ORU task –HST Electronics Control Unit insertion/removal Robotic ORU task –Remote Power Controller Module insertion/removal

10. Space Systems Laboratory University of Maryland Ranger Robotics Program: Status Report 10 End Effectors Microconical End Effector Bare Bolt Drive EVA Handrail Gripper Tether Loop Gripper SPAR Gripper Right Angle Drive

11. Space Systems Laboratory University of Maryland Ranger Robotics Program: Status Report 11 Operating Modalities Flight Control Station (FCS) –Single console –Selectable time delay »No time delay »Induced time delay Ground Control Station –Multiple consoles –Communication time delay for all operations –Multiple user interfaces »FCS equivalent interface »Advanced control station interfaces (3-axis joysticks, 3-D position trackers, mechanical mini-masters, and force balls) CPU (Silicon Graphics O2) Keyboard, Monitor, Graphics Display 2x3 DOF Hand Controllers Video Displays (3)

12. Space Systems Laboratory University of Maryland Ranger Robotics Program: Status Report 12 Neutral Buoyancy Vehicle I (RNBV I) –Free-flight prototype vehicle operational since 1995 –Used to simulate RTSX tasks and provide preliminary data until RNBVII becomes operational RNBV II is a fully-functional, powered engineering test unit for the RTSX flight robot. It is used for: Ranger Neutral Buoyancy Vehicles –Supporting development, verification, operational, and scientific objectives of the RTSX mission –Flight crew training –Developing advanced scripts –Refining hardware –Modifying control algorithms –Verifying boundary management and computer control of hazards –Correlating space and neutral buoyancy operations An articulated non-powered mock-up is used for hardware refinement and contingency EVA training

13. Space Systems Laboratory University of Maryland Ranger Robotics Program: Status Report 13 Graphical Simulation Task Simulation Worksite Analysis GUI Development

14. Space Systems Laboratory University of Maryland Ranger Robotics Program: Status Report 14 Simulation Correlation Strategy Simulation Correlation EVA/EVR Correlation Simulation Correlation EVA/EVR Correlation All On-Orbit Operations Performed Pre/Post Flight with RTSX Neutral Buoyancy Vehicle for Flight/NB Simulation Correlation All On-Orbit Operations Performed Pre/Post Flight with RTSX Neutral Buoyancy Vehicle for Flight/NB Simulation Correlation

15. Space Systems Laboratory University of Maryland Ranger Robotics Program: Status Report 15 Computer Control of Hazards Human response is inadequate to respond to the robot’s speed, complex motions, and multiple degrees of freedom Onboard boundary management algorithms keep robot from exceeding safe operational envelope regardless of commanded input

16. Space Systems Laboratory University of Maryland Ranger Robotics Program: Status Report 16 Program Status 1995: RNBV I operations began at the NBRF 1996: Ranger TSX development began June 1999: Ranger TSX critical design review December 1999: Space Shuttle Program Phase 2 Payload Safety Review April 2000: EVA mock-up began operation (62 hours of underwater test time on 45 separate dives to date) October 2001: Prototype positioning leg pitch joint and dexterous arm wrist began testing Today: RNBV II is being integrated; 75% of the flight robot is procured January 2002: RNBV II operations planned to begin Ranger TSX is #1 cargo bay payload for NASA’s Office of Space Science and #2 on Space Shuttle Program’s cargo bay priority list

17. Space Systems Laboratory University of Maryland Ranger Robotics Program: Status Report 17 Results of a Successful Ranger TSX Mission Demonstration of Dexterous Robotic Capabilities Pathfinder for Flight Testing of Advanced Robotics Dexterous Robotics for Advanced Space Science Precursor for Low-Cost Free-Flying Servicing Vehicles Understanding of Human Factors of Complex Telerobot Control Lead-in to Cooperative EVA/Robotic Work Sites