Modeling and Simulation of ABS through Different Types of Controllers Using Simulink

The ABS system is an abbreviation of the Anti-lock Brake System. Anti-lock brake system is the most important development in automotive technology for vehicle and traffic safety improvements. This system is used widely to ensure safe braking. Accident investigators have noticed that some of accidents happen and become a matter of concern, due to various human errors. But the most of traffic accidents occur because of faults in any mechanical system in vehicle, and/or bad condition of the roads. Bosch company was the leader in this field. It was the first company that invented and produced this system in 1978, and the brakes were designed in Anti-lock to implement the technique of braking technology automatically without the intervention of the vehicle driver. Through an electro-hydraulic control system, where an electronic control unit works to control the activation or non-activation of the hydraulic control system via the controlling of screw valves based on the signal sent from a number of sensors and switches. As the wheel speed sensors work to determine the speed and slowdown of the wheels. This signal is sent to the electronic control unit, if the wheels are slowing sharply, i.e. about to close, the control unit issues instructions to the hydraulic group. Then hydraulic group will reduce the brake pressure on these tires. And prevent the lock from occurring. When the driver continues to press the brake pedal, the pressure rises again. And this process is repeated several times until the vehicle stops completely. In this thesis, the subsystems and dynamics of ABS will be explained. Then a model of ABS will be created in MATLAB/SIMULINK software. While simulation of ABS model achieved by applying different control strategies as: Bang-bang which acts as on/off, PID and PD controller, with a vehicle speed of 100km/hr moving in straight line. Simulation will analyze the behavior of vehicle under application of ABS and without implementation of ABS mode, through different road types. Keywords: Anti-lock braking system (ABS), locking, slipping, PID controller, PD controller, simulation, vehicle dynamics.