Experimental Study on the Effect of Emergency Braking without Anti-Lock Braking System to Vehicle Dynamics Behaviour

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 vehicl

Investigation on vehicle dynamic behaviour during emergency braking at different speed

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

Plugging brake system as a hill descend control for electric powered wheelchair: Experimental analysis

The common brake system for the electric powered wheelchair (EPW) is the mechanical brake system. Although the mechanical brake system is compact, the brake performance is depending on the user’s hand grip. During descending on the slope, due to the gravitational force, the possibility of EPW to accelerate is high. In this study, by using the plugging brake system strategy, the hill descend control is proposed to control the speed of EPW. The plugging brake system will maintain the speed of EPW same as the desired speed that set by the user. In this plugging brake control system, the PID control is applied to minimize the error between the actual and desired speed. The experiment is performed on the slope based on the requirement from the American Disability Act (ADA) with maximum angle of 8.1 degrees and the slope length is 5.4 m. From the experimental results, the speed of EPW is maintaining at the desired speed during descending on the slope. These results prove the plugging brake control system is suitable for hill descend contro

The investigation of vehicle dynamic behaviour during braking at different speed

Globally, vehicle accident is one of major causes of injuries and death. To minimise the number of accident, safety features were introduced to the vehicle. The safety features of the vehicle can be divided into two categories; passive safety such as seat belt and active safety like anti-lock brake system (ABS). In this study, the effect of ABS during panic braking is analysed to determine the vehicle dynamic behaviour. The vehicle modelling is developed in the Matlab-Simulink, and the numerical analysis was done in the three initial speeds, low, medium and high speed. The braking force for panic braking is set to 400N, and the effect of ABS to the vehicle dynamic behaviour is observed. From the simulation results, without ABS, the front tires were lock-up and the vehicle become skidding. However, when ABS is applied, the front and rear tires were not lock-up, and the vehicle is stable. This result shows that ABS can prevent the tire to lock-up and improve the safety of the vehicle

Parameters estimation and calibration of bldc motor for electric powered wheelchair

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 EP

Amalan Tidak Berintegriti: Remeh Tapi Salah

Kajian ini merupakan sebuah sorotan kajian mengenai integriti. Integriti merangkumi pelbagai nilai murni termasuk kesopanan, ketepatan, kebolehpercayaan, ketekunan, kemuliaan, kesederhanaan, ketinggian peribadi, jujur, ikhlas, amanah, berpegang pada janji, bercakap benar, dan pelbagai sifat positif lain. Akan tetapi, sesuatu organisasi tidak mampu mencapai kecemerlangan jika berlaku masalah dalaman yang berpunca dari integriti atau jika terdapat pengaruh luar yang tidak diselesaikan berikutan kelemahan institusi itu sendiri. Kebanyakan masalah integriti yang dibangkitkan adalah merujuk kepada hal-hal yang remeh yang sering berkait dengan bidang masing-masing, walau bagaimanapun, ia tetap salah dan perlu diperbetulkan. Oleh itu, terdapat keperluan terhadap mengenal pasti punca kelemahan pembudayaan dan penguatkuasaan integriti dalam sesuatu organisasi, khasnya dalam diri masyarakat. Hasil dari permasalahan yang berbangkit ini, dua kemungkinan telah digariskan yang bertujuan membincangkan faktor isu ini sukar menunjukkan yang ianya akan berakhir. Hasil sorotan kajian mendapati, pengetahuan dan pembudayaan tentang isu integriti dilihat menjadi kelemahan ketara dalam kegagalan pengaplikasian integriti dalam pekerjaan. Oleh itu, kefahaman tentang konsep integriti seorang kakitangan adalah perlu bagi memperlihatkan keselarasan antara kata-kata dengan perlakuan, bertindak bersandarkan kepada prinsip moral, etika dan undang-undang, serta mengutamakan kepentingan umum melebihi kehendak diri dan melakukan kerja dengan komprehensif, holistik dan relevan. Selain itu, budaya organisasi berlandaskan piawai etika yang tinggi harus menjadi penggerak dan pengaruh positif kepada amalan tingkah laku beretika dalam kalangan pekerja