No abstract

Autonomous vehicle is gaining popularity in the market worldwide. Most autonomous vehicle are based on electric vehicles since they are easy to control. The torque control of electric vehicles is precise and easy since electric motor torque can be manipulated by controlling the motor current. Furthermore, the load of the vehicle affects the motor torque of an electric vehicle. A higher vehicle load requires high motor torque to propel the vehicle. Often in autonomous vehicle, the vehicle parameters and stability measure are set within a limit based on standard vehicle settings. However, a vehicle loaded with extra mass on either side can offset these parameters affecting the efficiency of the controller. Thus, in this paper the effect of load on vehicle longitudinal and lateral forces is identified. A simulation model of a two rear in-wheel motored electric vehicle is developed. The model is used to analyze the effect of load on vehicle longitudinal and lateral forces. Based on the result, increasing the load on the side of direction of lateral motion increases the lateral force generated. The high lateral force causes the tires to approach the tire friction circle limit. This can affect the automated vehicle performance since the tires are in unstable region.

No abstract

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.

With recent advances in technologies such as those of semiconductors and actuators, easy-to-control compact actuators have been actively applied in various fields such as factory automation and precision machining. In the automobile industry, major manufacturers and venture companies are also concentrating on electric vehicle development. Ultra-compact mobility vehicles, which exhibit an excellent environmental performance and are highly convenient for short-distance movement, are becoming popular. However, owing to cabin space limitations, it is difficult to mount systems such as power steering for assisting steering operations, and such systems are currently not installed in most ultra-compact mobility vehicles. Our research group focused on a steer-by-wire system that does not require a physical connection between the steering wheel and the wheels. Using this system, the steering wheel can be installed without any constraints, and the cabin layout can be easily changed. The reaction torque applied to the steering wheel can be expected to provide an optimum steering feel to each driver by controlling the reaction-force-generating actuator output. Drivers with different heights and arm lengths were then grouped, and arm model calculation and electromyogram measurements obtained during steering operations were used to examine the muscle burden experienced during driving owing to differences in the drivers' physiques.