CIMAR Research
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Transcript of CIMAR Research
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CIMAR Research
Carl CraneCenter for Intelligent Machines and RoboticsUniversity of Florida
30 April 2012
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Center for Intelligent Machines and RoboticsCollege of Engineering
Topics
• Autonomous ground vehicles– static obstacles, DARPA Grand Challenge– urban environment, DARPA Urban Challenge– autonomous convoy operations– automated range clearance
• Mechanisms– force & position control– variable stiffness suspensions– tensegrity mechanisms applied to wave energy harvesting
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World Modeling (traversability grid)• 60 m 60 m grid with• grid resolution of 0.5 m 0.5 m
DARPA Grand Challenge
Problem Statement• given: a 225 km path defined by a series of waypoints
• navigate the entire path as quickly as possible
ladar
monocular vision ladar• sensors– pose
• Starfire GPS• Smiths Aerospace IMU
– obstacles• bumper height ladar
– terrain• two stationary ladar• image processing
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Center for Intelligent Machines and RoboticsCollege of Engineering 4
Grand Challenge Technical Challenges
1. off-line path planning
2. detection of static obstacles
3. environment data represen-tation and sensor integration
4. localization
5. interprocess communication and coordination of multiple threads on multiple computers
6. reconciliation of differences in estimated global pose, a priori data, and sensed information
7. fault tolerance
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Problem Statement• given: a road network data file and a mission file
• visit the waypoints listed in the Mission Data File while obeying traffic laws
• sensors– pose
• Novatel & Garmin GPS• GE Aerospace IMU
– obstacles & terrain• 6 Sick ladars• 2 long range ladars
– lane detection• 6 Bluefox cameras
Situation Assessment Specialist 1
Behavior Specialist 1
Smart Arbiter
Decision Broker
Intelligence Element
Receding Horizon
Controller
Primitive Driver
Control Element
Ladar 1Ladar 1
Ladar 1Ladar 1
Ladar 1Ladar 1 Camera 1 IMU GPS 1
Sensor Element
High Level Planner
Local World Model
Planning Element
FIN
DIN
GS
EVA
LUAT
EB
EHAV
IOR
S
SELECTBEHAVIOR
DARPA Urban Challenge
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Center for Intelligent Machines and RoboticsCollege of Engineering 6
New Technical Challenges
1. pavement (road) detection and lane detection2. detection and classification of dynamic objects3. reconciliation of differences in estimated global pose, a priori data,
and sensed information4. determination of appropriate behavior mode5. smooth transition of vehicle control between behavior modes
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Problem Statement• develop convoy with human operated lead vehicle and
robotic following vehicles
• implement the system without any use of GPS or radio communications between vehicles
• two approaches to measure distance and angle to lead vehicle
– tether based (Autonomous Solutions, Inc.)
– vision based (UF)• control algorithm guides
follower along relativepath of leader
Autonomous Convoy Operations
• tether approach • vision approach– infrared emitters attached to back of
leader vehicle– panning camera mounted on follower– measures distance and angle to leader
(exact same data as obtained by tether)
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Problem Statement• automate the four steps of range clearance
• vegetation removal• surface clearance• mapping of subsurface objects• digging and removal of subsurface objects
• ladar based modeling of environment
Automated Range Clearance
• objects classified as– ground– vegetation– tree
• time study conducted in Wyoming which compares manned performance to teleoperation to autonomous operation
tree
ground
vegetation
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Center for Intelligent Machines and RoboticsCollege of Engineering
Topics
• Autonomous ground vehicles– static obstacles, DARPA Grand Challenge– urban environment, DARPA Urban Challenge– autonomous convoy operations– automated range clearance
• Mechanisms– force & position control– variable stiffness suspensions– tensegrity mechanisms applied to wave energy harvesting
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Problem Statement• simultaneously control the twists of freedom and the
wrenches of constraint for a body that is in contact with its environment
Approach• utilize a screw theory based approach whereby the
compliance matrix K is computed and used to relate a change in the contact wrench, , to the change in relative pose (twist), , as
• twists that correct wrench errors are added to twists that allow motion
• passive compliant mechanism attached to end of industrial robot
Simultaneous Force and Position Control
• active planar platform with compliance used to manipulate heavy loads
• device being applied to problem of attaching ordnance to a plane
• object must be maneuvered while limiting the contact force with the plane
w
ˆDˆ w K D
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Problem Statement• Develop a suspension system that isolates a car body
from road disturbances by mechanically adjusting it’s effective stiffness
Approach• utilize a recently
designed variablestiffness springmechanism
• variable stiffness spring mechanism– effective spring stiffness varies as the pivot bar is
moved left and right
Variable Stiffness Suspensions
• suspension designed for automobiles • passing over speed bump at 40 mph
0 10 20 30 40 50 60 70 80 90-5
0
5
Rid
e C
omfo
rt
0 10 20 30 40 50 60 70 80 90-0.1
0
0.1D
efle
ctio
n
0 10 20 30 40 50 60 70 80 90-0.02
0
0.02
Roa
d H
oldi
ng
Distance (m)
TPSPassive VSSActive VSS
TPSPassive VSSActive VSS
TPSPassive VSSActive VSS
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Problem Statement• recover electrical energy from ocean
Possible Approaches• Ocean Waves
• Ocean Tides
• Ocean Currents
• Thermal Gradients
• Salinity Gradients
• tensegrity– combination of elements in tension and compression– introduced by Snelson and Fuller in 1950’s– have been applied to architecture
Tensegrity Mechanisms used for Wave Energy Harvesting
• water particle motion • energy harvester concept