A Design & Implementation of Collision Avoidance System

for Automobiles using Embedded System

Need for this System

The industry strategy for automotive safety systems has been evolving over the last 20 years.

Initially, individual passive devices & features such as seatbelts, airbags, knee bolsters, crush zones, etc. was developed for saving lives & minimizing injuries when an accident occurs.

Later, preventive measures such as improving visibility, headlights, windshield wipers, tire traction, etc were included to reduce the probability of getting into an accident.

Now we are at the stage of actively avoiding accidents as well as providing max protection to the vehicle occupants and even pedestrians.

Overview of CAS

In this dissertation, advanced ideas such as pre-crash sensing, ultrasonic sensor is used to sense the object in front of the vehicle & gives the s/g to the micro controller unit.

Based on the signal received from the ultrasonic sensor, the micro controller unit sends a s/g to the braking unit for applying the brake automatically as per braking & throttle control logic fed in to the micro controller unit.

Overview of Embedded System

A typical embedded system has several input, output, memory subsystem.

The memory subsystem stores the instruction that controls the operation of the system.

These instruction comprise to program that the system execute.

The instruction to be carried out is written in any assembly language (or) Embedded C, C++ languages.

Here designing includes requirement analysis this involves a detailed examination of the user needs, the problem to be solved.

Hardware may be custom designed to follow any of the accepted industrial standards.

Microprocessor & Microcontrollers

The terms processor refers to any 3 types of devices known as microprocessors, microcontrollers & 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 PC & high-end workstations. The most common microprocessors are members of Motorola’s 68k-found in older Macintosh computer & the ubiquitous 80X86 families.

A microcontroller is similar to a microprocessor, except that it has been designed specifically for embedded systems.

Microcontroller typically include a CPU, memory & other peripherals in the integrated circuit. Common eg are the 8051, Intel’s 80196 & Motorola’s 68HCxx series.

Hardware & Software Initialization

Working of CAS

Block Schematic diagram of Ultrasonic Sensor

System Details

As per the design an ultrasonic distance measurement sensor has been proposed as obstacle detecting sensor

The inductive sensor, which gives the pulses to the Micro-Controller is the source for vehicle speed measurement

The Rotary potentiometers are used here as the pedal position sensor for both Accelerator as well as Brake

The actuator proposed here is stepper motor for both throttle and brake control

Stepper motor can be rotate as steps so that we can achieve similar to the normal operation of the throttle and brake pedals

Reaction Time & Stopping Distances

In our studies we investigated the effects of luminance, contrast & spatial frequency on reaction time.

As expected, we found that visual reaction time increases with reducing target visibility.

Reaction time varied from 200 ms in optimal conditions, usually encountered during daytime driving (i.e. high contrast, photonic luminance), to about 600 ms in non-optimal conditions experienced during night driving (i.e. low luminance, low contrast)

The "thinking distance" is a component, which includes the visual reaction time, the pedal response & the mechanical action of the brakes.

The "braking distance" is the time taken to decelerate to zero Kmph.

Factors affecting Stopping Distances

Stopping distance of the car will shorten as the mass increases due to friction effect.

Greater speed should mean greater stopping distance.

Aerodynamics will affect the stopping dist because the more aerodynamic the object in this case, the car has less air resistance.

The surface on which the car is to stop on will affect the stopping distance. for example if the road surface is textured, it will require more energy from the car to overcome friction

Gravity would affect the friction between the car & the road therefore it increases the stopping distance

CONCLUSION

Collision avoidance systems are especially useful in bad weather conditions.

The sensors in the car would be capable of detecting the poor conditions & would inform the driver on how to drive in them.

For example, because fog affects visibility, the sensors would recognize this & 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.

Implementing this concept as a project in a more economical way

Implementing another concept of Reverse Breaking System(RBS) along with this project

FUTURE WORK

REFERENCES

S. M. Metev and V. P. Veiko, Laser Assisted Microtechnology, 2nd ed., R. M. Osgood, Jr.Ed. Berlin, Germany: Springer-Verlag, 1998.

J. Breckling, Ed., The Analysis of Directional Time Series: Applications to Wind Speed and Direction, ser. Lecture Notes in Statistics. Berlin, Germany: Springer, 1989, vol. 61.

S. Zhang, C. Zhu, J. K. O. Sin, and P. K. T. Mok, “A novel ultrathin elevated channel low-temperature polySi TFT,” IEEE Electron Device Lett., vol. 20, pp. 569–571, Nov. 1999. (2002) The IEEE website. [Online]. Available: http://www.ieee.org/

M. Shell. (2002) IEEEtran homepage on CTAN. [Online]. Available: http://www.ctan.org/tex-archive/macros/latex/contrib/supported/IEEEtran/

FLEXChip Signal Processor (MC68175/D), Motorola, 1996.(2002) The IEEE website. [Online]. Available: http://www.ieee.org/

M. Shell. (2002) IEEEtran homepage on CTAN. [Online]. Available: http://www.ctan.org/tex-archive/macros/latex/contrib/supported/IEEEtran/

FLEXChip Signal Processor (MC68175/D), Motorola, 1996.“PDCA12-70 data sheet,” Opto Speed SA, Mezzovico, Switzerland.

R. E. Sorace, V. S. Reinhardt, and S. A. Vaughn, “High-speed digital-to-RF converter,” U.S. Patent 5 668 842, Sept. 16, 1997.

THANK YOU!!!

ANY QUERIES???