Transcript Estie mod magna faccum zzrilit velendit

Navi
Rutgers University
2012 Design Presentation
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Mechanical Design
• Entirely custom chassis
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Designed using SolidWorks
80/20 aluminum framing
0.25” polycarbonate casing
240 lb, including payload
• Brushed DC drive motors
– 80 W, 500 CPR optical encoders
– 5.6 mph maximum speed
– 27% maximum grade
• Actively air cooled by six fans
– 100 cfm airflow through chassis
– Modeled using CFD simulation
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Electrical: Power Distribution
• Optima YellowTop Battery (×2)
– 12 V lead acid batteries (in series)
– 35 A·h capacity
• Low power consumption
– 400 W loaded, 215 W idle
– 2+ hour battery life
• 24 V, 12 V, and 5 V DC buses
– 85%+ efficiency DC-DC regulators
– Isolated grounds limit noise
• Dashboard
– Switches for major components
– Dot matrix display status indicator
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Software Architecture
• Use and contribute to open source software when possible
• Built on the Robot Operating System (ROS) framework
• Three-dimensional Gazebo simulation of driving and sensors
Gazebo
Localization
Planning
Gazebo
Perception
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Gazebo Simulation
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Localization: Sensors
GPS: Novatel ProPak V3
• 2 Hz sample rate
• 15 cm accuracy (1 sigma)
• OmniSTAR HP corrections
Compass: PNI Fieldforce TCM
• 50 Hz sample rate
• 0.3° heading accuracy (RMS)
• 360° tilt correction
Odometry: US Digital Encoders
• 500 CPR, 0.5 mm resolution
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Localization: Extended Kalman Filter
• Fuse sensors to estimate pose
– Odometry: fast, relative pose
– Compass: fast absolute orientation
– GPS: accurate absolute position
• Non-linear “turn-drive-turn” model
(Source: Probabilistic Robotics)
Hardware
Simulation
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Perception: Sensors
Laser: Hokuyo UTM-30LX
• 40 Hz sample rate
• 240° field of view
• 30 m maximum range
Cameras: AVT Manta G-125C (×2)
• 15 FPS, synchronized
• 646 × 482 resolution
• 90° × 65° wide angle lens
• 130° combined field of view
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Perception: Laser Field of View
240°
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Perception: Sensors
Laser: Hokuyo UTM-30LX
• 40 Hz sample rate
• 240° field of view
• 30 m maximum range
Cameras: AVT Manta G-125C (×2)
• 15 FPS, synchronized
• 646 × 482 resolution
• 90° × 65° wide angle lens
• 130° combined field of view
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Perception: Camera Field of View
20 m
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Perception: Line Detection
Original Image
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Color
Transformation
Width Filter
Uses the HSV color space to limit the impact of illumination
Width filter is generated from the calibrated camera matrix
Pipelined with left and right images processed in parallel
Total processing time is 100 ms per image pair
Pipelining allows for a 50% increase in sample rate
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Mapping
Local Costmap: (10 m)2
• 5 cm square cells; high resolution
• Always centered on the robot
 Used by the local planner
Global Costmap: (1000 m)2
• 25 cm square cells; low resolution
• Origin fixed by a GPS coordinate
 Used by the global planner
• Sensors mark and clear observations
• Based on the ROS navigation stack
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Planning
Global Planner (on demand)
• Weighted A* Search
• Inverse of distance for <1 m
• Constant for ≥1 m
Local Planner (20 Hz)
• Dynamic Window Approach
• 10 linear velocity samples
• 15 angular velocity samples
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Questions?
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