Electric power steering: An overview of dynamics equation and how it's developed for large vehicle

Development of steering system has begun with manual steering, hydraulic power steering, and electric power steering. At present, the market trend shows that electric power steering is preferred compared to the other two steering systems, namely manual steering and hydraulic power steering. Electric power steering was chosen because of its light operation and ease in the control system. Although for large vehicles each tends to use hydraulic power steering. In this paper, we will explain about the existing dynamic motion equation models in electric power steering. Electric power steering uses a motor booster as a driver assist in driving the steering rod. The booster motor position on the electric power steering is in the steering column or on the steering rack. The booster position of the motor will affect the shape of the overall dynamic motion of the electric power steering system. Initially, research on the dynamic equation of the electric power steering system only involved the inertial component and the stiffness of the steering wheel and column steering components. In the next study, it has developed involving elements of damping and also forces of the wheels and roads. The components included in this movement are also increasing, namely, rack and pinion, tie rod, and drag link. This element is due to the more accurate calculation of the torque needed by the motor booster and its control system. In large cars, the difference between city cars is the distance from the steering rod, which is 2380 mm or almost 2-4 times that of the city car, so the similarity of the motion will also be different. Stiffness equation is needed for the drag link mechanism structure, which involves more stems combined between truss and frame. This mechanism is what distinguishes it later with the equation of the dynamic motion of the electric power steering system with the city car and its kind.