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7/29/2019 Adaptive Cruise Control Modified
http://slidepdf.com/reader/full/adaptive-cruise-control-modified 1/26
By
Archana devi
7/29/2019 Adaptive Cruise Control Modified
http://slidepdf.com/reader/full/adaptive-cruise-control-modified 2/26
Overview
Introduction
Components
Design
Implementation
Results and Observations
Further Work References
Demo/Video
7/29/2019 Adaptive Cruise Control Modified
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Goals of the Project
Study the ACC application and to identify
Components
Algorithms
Real-Time Issues
Real-Time approach to Design
Setup a basic platform
7/29/2019 Adaptive Cruise Control Modified
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Introduction to ACC
• Extension of Cruise Control.
• Operates either in
• Distance Control state
• Speed Control state
Des_Dist = Hos t_Vel * Timegap + ∆ where
Host_Vel is Host Vehicle velocity
TimeGap is set by the driver
∆ for additional safety
7/29/2019 Adaptive Cruise Control Modified
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Requirements
Functional: Detect leading vehicle.
Maintain desired speed.
Maintain desired timegap.
Communicate actions to User Interface
Non-Functional (timing constraints):
Response Time
Data update rate and so on…
ISO Limitations:
mean dec ≤ 3.0 m/s2 (over 2 s),
acceleration ≤ 2 m/s2
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Overview
Introduction
Components
Design Implementation
Results and Observations
Further Work References
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Components of ACC
Sensors:Four Wheel Sensors, Brake Pedal Sensor, Throttle Pedal Senor, Radar …
Actuators:
Brake Actuator, Throttle Actuator.
Controllers:
High level & Low level controller.
Communication Medium
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Overview
Introduction
Components
Design Implementation
Results and Observations
Further Work References
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Functionality and Data Flow
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Issues
With mode-changes: How many modes
When to switch mode
Schedulability
What triggers mode change Chattering
With Data Repository
How many levels When to update
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Solution to mode-change
How many?
Two: Safety-Critical(SC), Non-Safety Critical(NC)
When to switch?
Finish task execution.
Schedulability
Static checking.
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Solution to mode-change…
What triggers mode
change?LeadDist RoD Mode
FAR DECR-FAST SC
FAR INCR-FAST NC
FAR DECR-SLOW NC
FAR INCR-SLOW NC
CLOSE ---- SC
FOLLOW ---- RETAINLeadDist & RoD
LeadDist OR
RoD OR
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Solution to mode-change…
Chattering
In SC Mode:
(Safe_Dist + < Curr_Dist ≤ Follow_Dist - ) ||
(Follow_Dist + < Curr_Dist ≤ Radar_Dist && RoD = DECR -FAST) ||
(Follow_Dist - < Curr_Dist ≤ Follow_Dist + && Curr_Mode = SC)
In NC Mode:
(Follow_Dist + < Curr_Dist ≤ Radar_Dist && RoD ≠ DECR -FAST) ||
(Follow_Dist - < Curr_Dist ≤ Follow_Dist + && Curr_Mode = NC)
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Solution to Data Repository
How many levels
Example:
First-Level: Raw data from radar, wheel sensor, etc…
Second-Level: Host Velocity, Lead Distance, etc…
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Solution to Data Repository…
• When to update
First-Level: Continous
Second-Level: On-Demand based on R(d)
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Scheduling
Mode-Change approach
All Tasks are identified in advance.
All tasks are periodic.
RMS
Data Repository approach
Aperiodic tasks. Guarantee to aperiodic tasks.
CBS
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Overview
Introduction
Components
Design Implementation
Results and Observations
Further Work References
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Implementation
Hardware
Ultra-sonic Distance Meter (UDM)
○ Purpose: leading vehicle distance
○ Range: 1.3m
○ Accuracy: ± 2.5cm○ Sampling Rate: 1 per sec
Shaft Encoder (ENC)
○ Purpose: Host Velocity
○ Resolution: 1 cm per step
Communication (PC Robot)
○ Printer PortVer – 1: Leader and Follower
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Follower Version-2
Front view Side View
• UDM
• Range: 2m, Accuracy: ± 1cm, Sampling Rate: 10 per sec
• Shaft Encoder
• Resolution: 0.4cm
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Overview
Introduction
Components
Design Implementation
Results and Observations
Further Work References
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Results & Observations
• Cruise Control Operation
• Set speed = 35 m/s2
• Open-loop lower controller
•Shaft encoder
error
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Results & Observations…
• Constant Leading Distance• LeadDist = 63 cm
• Timegap = 1.8 s
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Results & Observations…
• Linear Increase-Decrease• Timegap = 1.5 s
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Results & Observations…
• Two-Level Repository
• Tested for UDM_RD Task
•Lead Dist = 69 cm
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Overview
Introduction
Components
Design Implementation
Results and Observations
conclusion
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