Document Type : Original Article
Authors
1
Professor, Automotive Technology Department, Faculty of Technology and Education, Helwan University, Cairo, Egypt.
2
Teaching Assistant, Automotive Technology Department, Faculty of Industrial Education, Sohag University, Sohag, Egypt.
3
Associate professor, Production Technology, Faculty of technology and Education, Helwan University, Cairo, Egypt.
Abstract
A novel automatic braking system is designed in this research to decrease vehicles accidents caused by obstacles. A safer automatic braking system that can handle less driver attention to the driving is developed. The proposed system is operated by means of three parts; the sensing part, the control unit, and the actuator used. A proper hydraulic mechanism is used to operate and control the braking system automatically, this system can operate the brake pedal according to the control unit signals. The system senses the distance between obstacles and the vehicle using an ultrasonic sensor, then an electric pump provides a fluid flow and pressure value through the use of two solenoid valves which control the direction of brake fluid in the hydraulic braking system. In case the driver does not push the brake pedal manually in the right time, the system automatically stops the vehicle without the driver input. A vehicle model was developed and simulated. Braking distance, time analysis, vehicle, wheel and wheel slip models were produced mathematically, and the vehicle dynamics were simulated in SimMechanics. The open loop dynamics gave a far slip ratio value from the desired value. Reversely, in the closed loop dynamics simulation the slip ratio value followed the reference signal in an accepted manner. The system was experimentally assisted in terms of braking time, and the performance was acceptable. The errors between the measured and theoretical braking time and the theoretical braking time were nearly one and two percent.
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