Transcript Ranger Telerobotics Program

Ranger Telerobotics Program
Brian Roberts
University of Maryland
Space Systems Laboratory
http://www.ssl.umd.edu/
On-Orbit Servicing Workshop
14 November 2001
Space Systems Laboratory
• 25 years of experience in space systems research
• Focus is to develop and test complete systems capable
of performing complex space tasks end-to-end
• People
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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 maximize involvement of students in
every level of research activities
Space Systems Laboratory
University of Maryland
SSL Assets for On-Orbit Servicing
• Development and testing of
multiple complete robotic
systems capable of performing
complex space tasks end-toend:
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• Expertise:
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Docking
Assembly
Inspection
Maintenance
• Facility for evaluating systems
in a simulated 6 degree-offreedom (DOF) microgravity
environment
Autonomous control of multiple robotic systems
Design of dexterous robotic manipulators
Adaptive control techniques for vehicle dynamics
Use of interchangeable end effectors
Investigation of satellite missions benefiting most from robotic servicing
Space Systems Laboratory
University of Maryland
What are the Unknowns in Space Robotics?
Human Workload
Issues?
Flexible Connections
to Work Site?
Capabilities and
Limitations?
Multi-arm Control and
Operations?
Control Station
Design?
Manipulator
Design?
Interaction with Nonrobot Compatible
Interfaces?
Hazard Detection and
Avoidance?
Utility of
Interchangeable
End Effectors?
Ground-based
Simulation
Technologies?
Ground Control?
Development,
Production, and
Operating Costs?
Effects and Mitigation
of Time Delays?
Space Systems Laboratory
University of Maryland
Multimode Proximity Operations Device (MPOD)
• System to evaluate
controls associated
with robotic docking
• Full 6 DOF mobility
base
• Full state feedback
through an on-board
sensor suite,
including an
acoustic-based
sensor system
• Probe-drogue docking system
• Operational since 1986
• Achievements:
– Autonomous approach and docking
– Maneuvering and berthing of large masses
– Application of nonlinear adaptive neural network control system
Space Systems Laboratory
University of Maryland
Supplemental Camera and Maneuvering Platform
• Supplemental Camera and
Maneuvering Platform
(SCAMP) is a free-flying
camera platform
– 6 DOF mobility base
– Stereo video and close-up color
cameras
• Originally used to observe
neutral buoyancy
operations
• Evolved to evaluate
robotic inspection
• Operational since 1992
• Achievements:
– Used routinely to observe robotic and non-robotic neutral buoyancy
operations
– Demonstrated visual survey and inspection
Space Systems Laboratory
University of Maryland
SCAMP Space Simulation Vehicle (SSV)
• Continuation of SCAMP’s
evolution into a high fidelity
neutral buoyancy simulation of
6 DOF space flight dynamics
– Uses onboard sensors (3-axis gyros,
accelerometers, magnetometers, and
a 3-D acoustic positioning system) to
accurately calculate its position,
attitude, and translational and
rotational velocities
– Robot is positioned to a specified
location, determined by a
mathematical computer simulation
• Operational since 1997
• Achievements:
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Cancellation of water drag effects for flight dynamics
Model-referenced vehicle flight control
Adaptive control of unknown docked payloads
Autonomous docking
Different methods of trajectory planning are being investigated
Space Systems Laboratory
University of Maryland
Beam Assembly Teleoperator (BAT)
• Free-flying robotic system to demonstrate assembly of an
existing space structure not robot friendly:
– 6 DOF mobility base
– 5 DOF dexterous assembly manipulator
– Two pairs of stereo monochrome video
cameras
– Non-articulated grappling arm for grasping the
structure under assembly
– Specialized manipulator for performing the
coarse alignment task for the long struts of the
truss assembly
• Operational since 1984
• Achievements:
– Combination of simple 1 DOF arm with dexterous 5 DOF manipulator
proved to be a useful approach for assembly of a tetrahedral structure
– Demonstrated utility of small dexterous manipulator to augment larger,
less dexterous manipulator
– Assisted in the change out of spacecraft batteries of Hubble Space
Telescope
Space Systems Laboratory
University of Maryland
“Ranger” Class 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 Laboratory
University of Maryland
Ranger Telerobotic Shuttle eXperiment (RTSX)
• 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
Space Systems Laboratory
University of Maryland
Ranger’s Place in Space Robotics
How the Robot Interacts with the Worksite
How the Operator Interacts with the Robot
Locally
Teleoperated
Specialized
Robotic
Interfaces
SRMS/SSRMS
MFD/SPDM
AERCam
Any EVACompatible
Interface
Any HumanCompatible
Interface
Remote
(Ground)
Teleoperated
Supervisory/
Autonomous
Control
ETS-VII
ROTEX
Sojourner
Ranger TSX
Robonaut
Space Systems Laboratory
University of Maryland
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)
~1500 lbs weight; 14 length from base on SLP
» 25 lb of force and 200 ft-lbf
to outstretched arm tip
of torque; can withstand
250 lbf at full extension
while braked
Space Systems Laboratory
University of Maryland
Task Suite
• 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)
• Robotic ORU task
– Remote Power Controller
Module insertion/removal
• Robotic assistance
of EVA
– Articulating Portable
Foot Restraint
setup/tear down
• Non-robotic ORU
task
– HST Electronics
Control Unit
insertion/removal
Space Systems Laboratory
University of Maryland
End Effectors
Bare Bolt Drive
Right Angle Drive
Microconical
End Effector
Tether Loop
Gripper
EVA Handrail
Gripper
SPAR Gripper
Space Systems Laboratory
University of Maryland
Operating Modalities
• Flight Control Station
(FCS)
– Single console
– Selectable time delay
» No time delay
» Induced time delay
Video Displays (3)
Keyboard, Monitor,
Graphics Display
2x3 DOF
Hand Controllers
CPU (Silicon
Graphics O2)
• 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)
Space Systems Laboratory
University of Maryland
Ranger Neutral Buoyancy Vehicles
• 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:
– Refining hardware
– Modifying control algorithms and developing
advanced scripts
– Verifying boundary management and computer
control of hazards
– Correlating space and neutral buoyancy operations
– Supporting development, verification, operational,
and scientific objectives of the RTSX mission
– Flight crew training
• An articulated non-powered mock-up is used for
hardware refinement and contingency EVA training
Space Systems Laboratory
University of Maryland
Graphical Simulation
Task Simulation
GUI Development
Worksite Analysis
Space Systems Laboratory
University of Maryland
Simulation Correlation Strategy
EVA/EVR
Correlation
Simulation
Correlation
All On-Orbit
Operations Performed
Pre/Post Flight with
RTSX Neutral
Buoyancy Vehicle for
Flight/NB Simulation
Correlation
Simulation
Correlation
EVA/EVR
Correlation
Space Systems Laboratory
University of Maryland
Arm Evolution
Roboticus Dexterus
Roboticus Videus
Roboticus Grapplus
BAT Dexterous Arm (5 DOF)
ca. 1984
BAT Tilt & Pan Unit (2 DOF)
ca. 1984
BAT Grapple Arm (0 DOF)
ca. 1984
Ranger Dexterous Arm Mark 1 (7 DOF)
ca. 1994
Ranger Dexterous Arm Mark 2 (8 DOF)
ca. 1996
Ranger Grapple Arm (7 DOF)
ca. 1996
Ranger Video Arm (7 DOF)
ca. 1996
Ranger Positioning Leg (6 DOF)
ca. 1998
Space Systems Laboratory
University of Maryland
Program Status
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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: Mock-up began operation (62 hours of
underwater test time on 45 separate dives to date)
October 2001: Prototype positioning leg pitch joint and
Mark 2 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 Laboratory
University of Maryland
SSL Assets for On-Orbit Servicing
• Development and testing of
multiple complete robotic
systems capable of performing
complex space tasks end-toend:
–
–
–
–
Docking: MPOD and Ranger TFX
Assembly: BAT and Ranger
Inspection: SCAMP
Maintenance: Ranger
• Facility for evaluating systems
in a simulated 6 DOF
microgravity environment
• Expertise:
–
–
–
–
–
Autonomous control of multiple robotic systems
Design of dexterous robotic manipulators
Adaptive control techniques for vehicle dynamics
Use of interchangeable end effectors
Investigation of satellite missions benefiting most from robotic servicing
Space Systems Laboratory
University of Maryland
Backup Slides
Space Systems Laboratory
University of Maryland
Robot Stowed Configuration
Space Systems Laboratory
University of Maryland
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 Laboratory
University of Maryland
Results of a Successful Ranger TSX Mission
Demonstration of Dexterous
Robotic Capabilities
Precursor for Low-Cost
Free-Flying Servicing Vehicles
Understanding of Human Factors
Pathfinder for Flight
of Complex Telerobot Control
Testing of Advanced Robotics
Lead-in to Cooperative
EVA/Robotic Work Sites
Dexterous Robotics for
Advanced Space Science
Space Systems Laboratory
University of Maryland