25-08-2017, 09:32 PM
A Design & Implementation of Collision Avoidance System (CAS) for Automobiles using Embedded System
Automobiles using Embedded.doc (Size: 1.1 MB / Downloads: 39)
Abstract
The industry strategy for automotive safety systems has been evolving over the last 20 years. Initially, individual passive devices and features such as seatbelts, airbags, knee bolsters, crush zones, etc. was developed for saving lives and minimizing injuries when an accident occurs. Later, preventive measures such as improving visibility, headlights, windshield wipers, tire traction, etc. were deployed to reduce the probability of getting into an accident. Now we are at the stage of actively avoiding accidents as well as providing maximum protection to the vehicle occupants and even pedestrians. Systems that are on the threshold of being deployed or under intense development include collision avoidance systems.
INTRODUCTION
Despite all the advances made, the overriding vision of zero-accident motoring still remains a vision of unachieved. We need to reduce further the number of accident victims, and the use of new driver assistance systems will enable us to make significant progress in this field. Such systems represent the second revolution in active safety after Electronic Stability Program (ESP).
Our new electronic assistance will be systems that can “see” and therefore provide active operating support for drivers. The systems will also be able to see farther and take in a wider spectrum than any human ever could. The goal we have defined is to make vehicles of tomorrow capable of communicating with one another, and hence able to issue warnings to drivers concerning any imminent dangers. As a consequence for the medium term, driver assistance and communication systems will both be featured as integrated vehicle modules to reduce traffic accidents significantly. The top model in our range, the phaeton, is already available with the option of Automatic Distance Control (ADC), which is geared to maintain automatically a minimum distance from the vehicle ahead through system-initiated braking and acceleration.
Microprocessor & Microcontroller:
The terms processor refers to any three types of devices known as microprocessors, microcontrollers and digital signal processors. The name microprocessor is usually reserved for a chip that contains a powerful CPU that has not been designed with any particular computation in mind. These chips are usually the foundation of personal computers and high-end workstations. The most common microprocessors are members of Motorola’s 68k-found in older Macintosh computer – and the ubiquitous 80 x 86 families.
A microcontroller is very much like a microprocessor, except that it has been designed specifically for use in embedded systems. Microcontroller typically include a CPU, memory and other peripherals in the integrated circuit. Common examples are the 8051, Intel’s 80196 and Motorola’s 68HCxx series. PIC 16F876, PIC 18C84.
PROJECT OVERVIEW
This project aims in developing and demonstrating a collision avoidance system that improves safety. The implementation of collision avoidance system (CAS) in vehicle improves highway traffic safety significantly. These electronic systems scan the direct environment of the vehicle, predicting the danger. A wide range of possible CAS was researched and developed, varying from systems which support the driver on one specific driving task (e.g., proper distance keeping, blind spot obstacle warning and lane keeping) up to more advanced systems where the driver’s throttling, and braking tasks are totally controlled in case of predetermined collision.
REACTION TIMES AND STOPPING DISTANCES
In our studies we investigated the effects of luminance, contrast and spatial frequency on reaction time. Of particular interest were the combinations of parameters, which simulate urban night driving conditions that are low luminance, low contrast and low spatial frequencies. As expected, we found that visual reaction time increases with reducing target visibility. Reaction time varied from 200 msec in optimal conditions, usually encountered during daytime driving (i.e. high contrast, photonic luminance), to about 600 msec in non-optimal conditions experienced during night driving (i.e. low luminance, low contrast)
Conclusion
Collision avoidance systems are especially useful in bad weather conditions. The sensors in the car would be capable of detecting the poor conditions and would inform the driver on how to drive in them. For example, because fog affects visibility, the sensors would recognize this and alert the driver of any dangers that lie ahead, like a windy turn or another car, giving the driver enough time to slow down, allowing him to escape from what could have been a bad accident.