Adaptive cruise control edit1
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Adaptive cruise control (ACC) uses radar and other sensors to detect vehicles ahead and maintain a safe following distance without requiring driver input. It works by detecting the distance and speed of other vehicles using radar and adjusting the vehicle's speed using the brake and throttle to keep a safe distance. Newer ACC systems fuse radar and camera sensors to better track vehicles. The controller processes sensor data and controls the engine or brakes. ACC allows more comfortable driving in traffic while increasing safety and fuel efficiency.
Adaptive cruise control edit1
- 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. Dept. of Instrumentation Technology 2
- 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. Dept. of Instrumentation Technology 3
- 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. Dept. of Instrumentation Technology 4
- 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 Dept. of Instrumentation Technology 5
- 6. Constituents Outputs : Alarms Flashed Messages Brake Control(Output to the pedal system for applying emergency brake) Dept. of Instrumentation Technology 6
- 7. Dept. of Instrumentation Technology 7
- 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. Dept. of Instrumentation Technology 8
- 9. Sensor The currently used „Pulse Doppler RADAR‟ uses the principle of 'Doppler effect‟ in determining the velocity of the target Dept. of Instrumentation Technology 9
- 10. Pulse Doppler Radar Dept. of Instrumentation Technology 10
- 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 Dept. of Instrumentation Technology 11
- 12. Fusion Sensor Dept. of Instrumentation Technology 12
- 13. Fusion Sensor Dept. of Instrumentation Technology 13
- 14. Fusion Sensor Dept. of Instrumentation Technology 14
- 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. Dept. of Instrumentation Technology 15
- 16. Controller Action Dept. of Instrumentation Technology 16
- 17. Motorola ACC Dept. of Instrumentation Technology 17
- 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. Dept. of Instrumentation Technology 18
- 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. Dept. of Instrumentation Technology 19
- 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 Dept. of Instrumentation Technology 20
- 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. Dept. of Instrumentation Technology 21
- 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. Dept. of Instrumentation Technology 22
- 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. Dept. of Instrumentation Technology 23
- 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. Dept. of Instrumentation Technology 24
- 25. Vehicles using ACC Porsche Panamera Volkswagen Passat Dept. of Instrumentation Technology 25
- 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. Dept. of Instrumentation Technology 26
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- 28. Dept. of Instrumentation Technology 28