Adaptive Cruise Control Modified

7/29/2019 Adaptive Cruise Control Modified

http://slidepdf.com/reader/full/adaptive-cruise-control-modified 1/26

By

Archana devi



Overview

Introduction

Components

Design

Implementation

Results and Observations

Further Work References

Demo/Video



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



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



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



Overview

Introduction

Components

Design Implementation





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



Overview

Introduction

Components






Functionality and Data Flow



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



Solution to mode-change

How many?

Two: Safety-Critical(SC), Non-Safety Critical(NC)

When to switch?

Finish task execution.

Schedulability

Static checking.



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



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)



Solution to Data Repository

How many levels

Example:

First-Level: Raw data from radar, wheel sensor, etc…

Second-Level: Host Velocity, Lead Distance, etc…



Solution to Data Repository…

• When to update

First-Level: Continous

Second-Level: On-Demand based on R(d)



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



Overview

Introduction

Components






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



Follower Version-2

Front view Side View

• UDM

• Range: 2m, Accuracy: ± 1cm, Sampling Rate: 10 per sec

• Shaft Encoder

• Resolution: 0.4cm



Overview

Introduction

Components






Results & Observations

• Cruise Control Operation

• Set speed = 35 m/s2

• Open-loop lower controller

•Shaft encoder

error



Results & Observations…

• Constant Leading Distance• LeadDist = 63 cm

• Timegap = 1.8 s




• Linear Increase-Decrease• Timegap = 1.5 s




• Two-Level Repository

• Tested for UDM_RD Task

•Lead Dist = 69 cm



Overview

Introduction

Components



conclusion

Adaptive Cruise Control Modified

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