adaptive cruise control by gurulingesh r. 03329008 kanwal rekhi school of information technology...

Adaptive Cruise Control

by

Gurulingesh R.

03329008

Kanwal Rekhi School of Information Technology

Indian Institute of Technology Bombay

Overview

• Motivation

• Adaptive Cruise Controller: An Example– Functional Model– Task Model

• Architecture

• Future Work

• References

Motivation

Motivation (Cont…)

– Partitioning of system into TT and ET domains

– Process Mapping

– Optimization of parameters corresponding to communication protocol.• Sequence and Slots of TDMA (TTC)• Priorities of Messages (ETC)

– Schedulability

Adaptive Cruise Control

• Adaptive Cruise Control:

– automatically adjusts vehicle speed to maintain a driver-selected safe distance from the vehicle ahead in the same lane.

– It then returns to the set speed when traffic clears.

• Requirements:

– The speed should be kept close to the SET speed, if there is no vehicle ahead.

– Timegap should be maintained at x sec.

Requirements (cont…)

– Detect the manual intervention by Driver.– Indicate thru UI, the action being taken by

ACC.– Should be activated above xkmph.– Velocity changes should be smooth in the

speed control mode to make the ride comfortable.

– Etc…

Functions Identified• Computing Current speed of our vehicle

• Leading Vehicle related Task

• Controlling Speed of our Vehicle

• Controlling the Throttle

• Controlling the Brake

• Detecting Manual Intervention

• UI to the Driver

• Periodicity of Tasks

• Hard, Firm; Periodic, Aperiodic…

Components Needed• Sensors:

– Four Wheel Sensors– Brake Pedal Sensor– Accelerator Pedal Senor– IR Sensor– Throttle position Sensor– Brake Actuator position Sensor

• Actuators:– Brake Actuator– Throttle Actuator

g

a

b

Wheel S

IR S

f

Speed Set

Throttle S

Brake S

c

d

e

Throttle A

Brake A

Curr_Thr Pos

Curr_Br Pos

Precedence Graph showing communication relation

Src: Prof. Shashikant's Control System Lec-1 in DEP Mode

ACC System Design

(desired vehicle speed)(desired vehicle speed)

Control I/PControl I/PPhysical Physical ProcessProcess

SensorsSensors

ActuatorsActuators

AdaptiveAdaptive

Cruise Cont.Cruise Cont.

Reference InputReference Input

Actual outputActual output

Sensor NoiseSensor Noise

Actuator NoiseActuator Noise

Sensed O/PSensed O/P

DesiredDesired

Control I/PControl I/P

DisturbancesDisturbances(accelerator pedal (throttle) position, brake pedal position)(accelerator pedal (throttle) position, brake pedal position)

(wheel speed sensor)(wheel speed sensor)

(air drag, grade,(air drag, grade,

friction etc)friction etc)

(vehicle speed)(vehicle speed)

Block Diagram

Block Diagram (cont…)

• Three Control Loops:– Outer loop does the entire process of

deciding whether to accelerate or decelerate or to maintain the same speed.

– Two Inner loops are special actuation loops that control the throttle and brake control systems

Task Graph

ACC Control Algorithm

• Algorithm will mainly have three features:– maintain the speed set by the driver if there

is no leading vehicle.– to adjust the speed of the vehicle

appropriately to maintain the desired safe distance from leading vehicle

– to switch back and forth between above two modes according to the situation.

Flow Chart

Flow Chart

(cont…)

State

Diagram

Src: Prof. Shashikant's Control System Lec-1 in DEP Mode

Process Model

Physical Physical ProcessProcess

Actual OutputActual Output

Control I/PControl I/P

DisturbancesDisturbances

EE 1/M1/MGG 1/R1/Rww

Physical Positioning of the Components

Wheel SpeedSensor FR

Wheel SpeedSensor FL

Wheel SpeedSensor RL

Wheel SpeedSensor RR

Brake RLActuator

Brake RRActuator

Brake FLActuator

Brake FRActuator

Brake Pedal Sensors

Accelerator Pedal Sensors

Radar/Sensor/Camera

NODE-FL

NODE-RR

NODE-FR

NODE-RL

NODE -OBSTACLE

DETECTION

MAIN-NODE

velRR-Sensor

RR-Actuator

velFR-Sensor

FR-Actuator

velRL-Sensor

RL-Actuator

velFL-Sensor

FL-Actuator

Brake-Pedal-Sensor

Accelerator-Pedal-Sensor

Future Work

• Classifying tasks as TT and/or ET and as Soft, Hard or Firm.

• Writing Algorithm

• Allocation of Tasks

• Schedulability

• One or two similar application if time permits

Some of the References• Paul pop et. al. “Design Optimization of Multi-Cluster Embedded

Systems for Real-Time Applications”, Date’04, Paris, France, February 16-20, 2004, pp. 1028-1033 .

• Jakob Axelsson, “A case Study in Heterogeneous Implementation of Automotive Real-Time Systems”, 6th International Workshop on Hardware/Software CoDesign, Seattle, March 15-18, 1998.

• Krithi Ramamritham, “Allocation and Scheduling of Precedence-Related Periodic Tasks”, IEEE Transaction in Parallel and Distributed Systems, 1995, pp. 412-420.

• Cecilia Ekelin, Jan jonsson, “Real Time System Constraints: Where do they Come From and where do they Go?”, In Proceedings of the Int’l Workshop on Real Time Constarints, Oct. 16, 1999, USA, pp. 53-57.

• Kristina Ahlström, Jan Torin, “Design Method for Conceptual Design of By-Wire Control: Two Case Studies”, 7th Int’l conference on Engineering of Complex Computer Systems, June 11-13, 2001.