Safety system of the vehicle can be divided into two main categories; passive and active safety system. The purpose of the passive safety system is to protect the occupant during an accident, while active safety system allows the vehicle to be manoeuvred to avoid any collision. Although active safety system can prevent the accident, in a critical situation such as emergency braking, the dynamic behaviour of the vehicle changes abruptly, and the vehicle becomes unstable. The objective of this study is to analyse the dynamic behaviour of the vehicle during emergency braking with and without anti-lock braking system (ABS). In this study, the dynamic behaviour of the vehicle is observed by the simulation model that has been developed in the MATLAB-Simulink. The analysis vehicle model is Universiti Malaysia Pahang (UMP) test car, model Proton Persona. During braking, when ABS control unit detect the wheel is to lock-up, the hydraulic control unit closed the hydraulic valve to release the brake pad on the wheel. This allows the wheel to spin intermittently during braking. From the simulation results, when ABS is not applied to the vehicle, the front tires were lock-up and the vehicle become skidding. However, when ABS is applied, the speed of all tires decreased gradually and the vehicle is not skidding. The simulation results also show that the stopping distance with ABS is improved 28% compared without ABS.

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In other to analyse the numerical analysis, parameters are very important in the mathematical modelling work. This process will determine the correspondence output between mathematical modelling and real system. In this paper, estimation and calibration method of brushless DC (BLDC) motor parameters that used in Electric Powered Wheelchair (EPW) through experimental and simulation comparison are proposed. The setup of experiment consist of in-wheel BLDC motor with a driver, 36 volt battery, Arduino microcontroller, speed sensor and current measurement tool. Firstly, the initial parameters of motor are estimated by using related equation and fitting curve method. Then, initial estimated parameters are simulated in EPW modelling. Finally, parameters of the BLDC motor is calibrated according to the output speed of modelling and real DC motor using MATLAB-Parameter Estimation tool. Result shows the similarity between the modelling and real EPW output speed is 97.8% similar after calibration. In conclusion, the calibrated parameters are verified to use in modelling and for the further work in control designing of the EPW.

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An anti-lock braking system (ABS) is a basic skid control system that can prevent the tire from locking up. In an emergency braking situation, a high possibility that the skidding phenomenon can occur without ABS. This incident become worse when an emergency braking is applied either on wet or dry surfaces. Although ABS is crucial to prevent the collision, some vehicles still do not have ABS. This study is aimed to analyse the vehicle’s dynamic behaviour during emergency braking on wet and dry surface condition. The experimental vehicle model is a Malaysian sedan car namely Proton Persona. This instrumented car is equipped with sensors,video camera and data acquisition systems to determine the vehicle’s motion. In the experiment,when the vehicle reached a maximum speed of 60 km/h, the driver push the brake pedal firmly until the car stop. From the experimental results, the effect of emergency braking without ABS is clearly seen at the wheel speed. The tire locked up can be observed when emergency braking was applied on the wet surface. However, for the emergency braking on the dry surface, the tire decreased gradually. This finding shows that without ABS, the vehicle is unsafe and accident can occur. The experimental data from this study also can be used as a guideline to a researcher and manufacturer in the development of ABS and safety system of the vehicle