Real Time systems

1. Adaptive Cruise
Control
BY
Shomik Mullick (1RV09IT040)
Siddharth D.C. (1RV09IT043)
Varun R. Athreya (1RV09IT065)
Dept. of Instrumentation Technology 1

2. Introduction
 The concept of assisting driver in longitudinal
vehicle control to avoid collisions is adaptive
cruise control.
 When switched on, this device takes up the task
of the task of accelerating or braking to
maintain a constant speed.
 An „Adaptive Cruise Control‟ (ACC) system
developed as the next generation assisted the
driver to keep a safe distance from the vehicle
in front.
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3. Principle
 ACC works by detecting the distance and speed
of the vehicles ahead by using radar system.
 The time taken by the transmission and
reception is the key of the distance
measurement.
 The shift in frequency of the reflected beam by
Doppler Effect is measured to know the speed.
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4. Principle
 Depending on this speed, the brake and
throttle controls are done to keep the vehicle
in a safe position with respect to the other.
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5. Constituents
 Inputs: Radar Beam
Delay Interval
Throttle position sensor
Brake Status
Speed calculated using speedometer
• Signals: ACC ON
Brake event(manual control)
Safe /Unsafe distance notification
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6. Constituents
 Outputs : Alarms
Flashed Messages
Brake Control(Output to the
pedal system for applying emergency brake)
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8. Sensor
 RADAR –
It is an electromagnetic system for the detection
and location of vehicles.
 It is operated by radiating energy into space and
detecting the echo signal reflected from an
object (target) .
 The reflected energy is not only indicative of the
presence but on comparison with the
transmitted signal, other information of the
target can be obtained.
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9. Sensor
 The currently used „Pulse Doppler RADAR‟ uses
the principle of 'Doppler effect‟ in determining
the velocity of the target
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10. Pulse Doppler Radar
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11. Fusion Sensor
 The new sensor system introduced by Fujitsu Ltd.
and Honda
 This includes millimetre wave radar linked to a
stereo camera with a 40 degree viewing angle
 These two parts work together to track the car
from the non-moving objects.
 Radar‟s target is the car‟s rear bumper, the
stereo camera is constantly captures all objects
in its field of view
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12. Fusion Sensor
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13. Fusion Sensor
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14. Fusion Sensor
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15. Controller Action
 1. Speed control- If there is no vehicle presently
in front, then the speed is controlled about a set
point just as in conventional cruise control
 2. Headway control- In order to keep a safe
distance between the vehicle s, the headway
control is required.
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16. Controller Action
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17. Motorola ACC
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18. Motorola ACC
 The sensor data such as Radar information, that from camera
and an IR sensor are processed.
 It is a throttle controller or an engine speed controller.
 It consists of
1. SRAM (1MB to10 MB)
2. FLASH 1MB
3. EEPROM (4KB to 32 KB)
4. Real time clock
5. 4 x UART interfaces
6. 3 X CAN interfaces
7. 64-bit floating point unit.
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19. Motorola ACC
 The MPC 565 can be programmed to
generate the control signals
 The throttle valve is actuated and the air
intake is controlled so the requirement of fuel
for the right proportion with the air also
increases.
 So more fuel is injected and engine speed is
changed.
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20. Motorola ACC
 HC12-
 The HC12 is a breaking controller which
receives data from the wheel speed sensors and
from the DSP module.
 It generates the braking control signal
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21. Motorola ACC
 CAN (Control Area Network) BUS-
• CAN BUS is the network established between
controllers
• It is a 2-wire, half-duplex, high speed network
for high speed high speed applications with
short messages
 It offers high speed communication rate up to
1Mbits per second and allows real time control.
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22. Motorola ACC
 Each module in the ACC connected to the CAN
is called „a node‟. All are acting as transceivers
 The actuator used for throttle control is a
solenoid actuator. The signal through the coil can
push or pull the plunger.
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23. Advantages
 The driver is relieved from the task of careful
acceleration, deceleration and braking in
congested traffics.
 A highly responsive traffic system that adjusts
itself to avoid accidents can be developed.
 Since the breaking and acceleration are done in
a systematic way, the fuel efficiency of the
vehicle is increased.
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24. Disadvantages
 A cheap version is not yet realized.
 A high market penetration is required if a
society of intelligent vehicles is to be formed.
 Encourages the driver to become careless. It can
lead to severe accidents if the system is
malfunctioning.
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25. Vehicles using ACC
Porsche Panamera
Volkswagen Passat
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26. References
 Willie D. Jones, “Keeping cars from crashing.”
IEEE Spectrum September2001.
 P.Venhovens, K. Naab and B. Adiprasto, “Stop And
Go Cruise Control”,
 International Journal of Automotive Technology,
Vol.1, No.2, 2000.
 Martin D. Adams, “Co axial range Measurement-
Current trends for Mobile
 Robotic Applications”, IEEE Sensors journal, Vol.2,
no.1 Feb.2002.
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