Gardell G. Gefke, Craig R. Carignan, Brian J. Roberts, and J. Corde Lane University of Maryland...
Transcript of Gardell G. Gefke, Craig R. Carignan, Brian J. Roberts, and J. Corde Lane University of Maryland...
Gardell G. Gefke, Craig R. Carignan, Brian J. Roberts, and J. Corde Lane
University of MarylandSpace Systems Laboratoryhttp://www.ssl.umd.edu/
Ranger Telerobotic Shuttle Experiment: Status Report
Intelligent Systems and Advanced Manufacturing ConferenceTelemanipulators and Telepresence Technologies VIII
28 October 2001
Space Systems LaboratoryUniversity of Maryland
Ranger Robotics Program: Status Report2
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
Space Systems LaboratoryUniversity of Maryland
Ranger Robotics Program: Status Report3
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 InterchangeableEnd Effectors?
ManipulatorDesign?
Hazard Detection and Avoidance?
Development, Production, and Operating Costs?Ground-based
Simulation Technologies?
Space Systems LaboratoryUniversity of Maryland
Ranger Robotics Program: Status Report4
“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
Space Systems LaboratoryUniversity of Maryland
Ranger Robotics Program: Status Report5
• 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)
Space Systems LaboratoryUniversity of Maryland
Ranger Robotics Program: Status Report6
LocallyTeleoperated
Remote(Ground)
Teleoperated
Supervisory/Autonomous
Control
SpecializedRobotic
Interfaces
SRMS/SSRMSMFD/SPDMAERCam
ETS-VIIROTEX
Sojourner
Any EVA-Compatible
InterfaceRanger TSX
Any Human-Compatible
InterfaceRobonaut
Ranger’s Place in Space RoboticsHow the Operator Interacts with the Robot
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Space Systems LaboratoryUniversity of Maryland
Ranger Robotics Program: Status Report7
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
Space Systems LaboratoryUniversity of Maryland
Ranger Robotics Program: Status Report8
Robot Stowed Configuration
Space Systems LaboratoryUniversity of Maryland
Ranger Robotics Program: Status Report9
• 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
Space Systems LaboratoryUniversity of Maryland
Ranger Robotics Program: Status Report10
End Effectors
Microconical End Effector
Bare Bolt Drive
EVA Handrail Gripper
Tether Loop Gripper SPAR Gripper
Right Angle Drive
Space Systems LaboratoryUniversity of Maryland
Ranger Robotics Program: Status Report11
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)
Space Systems LaboratoryUniversity of Maryland
Ranger Robotics Program: Status Report12
• 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
Space Systems LaboratoryUniversity of Maryland
Ranger Robotics Program: Status Report13
Graphical Simulation
Task Simulation
Worksite Analysis
GUI Development
Space Systems LaboratoryUniversity of Maryland
Ranger Robotics Program: Status Report14
Simulation Correlation Strategy
SimulationCorrelation
EVA/EVRCorrelation
SimulationCorrelation
EVA/EVRCorrelation
All On-OrbitOperations Performed
Pre/Post Flight withRTSX Neutral
Buoyancy Vehicle for Flight/NB Simulation
Correlation
All On-OrbitOperations Performed
Pre/Post Flight withRTSX Neutral
Buoyancy Vehicle for Flight/NB Simulation
Correlation
Space Systems LaboratoryUniversity of Maryland
Ranger Robotics Program: Status Report15
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
Space Systems LaboratoryUniversity of Maryland
Ranger Robotics Program: Status Report16
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
Space Systems LaboratoryUniversity of Maryland
Ranger Robotics Program: Status Report17
Results of a Successful Ranger TSX Mission
Demonstration of DexterousRobotic Capabilities
Pathfinder for FlightTesting of Advanced Robotics
Dexterous Robotics forAdvanced Space Science
Precursor for Low-CostFree-Flying Servicing Vehicles
Understanding of Human Factorsof Complex Telerobot Control
Lead-in to CooperativeEVA/Robotic Work Sites