System allowing adhesion force change of road vehicle

Abstract

Bringing the car into a skid is realised by the adhesion force decrease. This can be reached either by a coefficient of adhesion decrease or decrease of a radial reaction on the vehicle's wheel. For the purpose to the vehicle's behaviour change according to stability we chose the way of radial reaction change. To decrease the adhesion force transferred by the vehicle's wheels, the required part of radial reaction of a particular vehicle's wheel was transferred to the road, out of the vehicle's wheels, using additional auxiliary wheels. The auxiliary wheel units are connected to suspension arms. The article contains individual currently used ways for the adhesion force change and the unique way in the form of the system SlideWheel designed by the authors. The system SlideWheel, which was designed by the authors of this article, consists of three circuits. The first circuit is the mechanical part of the wheel unit, the second one is designed in the form of a hydraulic system and the third circuit is an electrical system used to control the wheel unit's lift through the hydraulic system. The system was designed to be used for experimental measurement purposes in education in order to experimentally simulate oversteer or understeer of the vehicle. The real measured data from a particular drive test are stated and evaluated in the conclusion. The measurement is implemented on a special experimental vehicle equipped with the SlideWheel system. Based on the experimental measurements, we have come to the conclusion that using the SW system, it is possible to change the adhesion force of a road vehicle.The paper deals with a new system for radial reaction change of vehicle wheels. This system has minimal added weight to the vehicle. At the same time, none of the components exceeds the ground plan of the vehicle. With the newly created system, it is possible to reduce radial reactions on any car wheel. The measured results are consistent with the vehicle's ride on sliding surfaces.

Modification of the Adhesive Force by Changing the Radial Reaction on Vehicle Wheels

“…The simulation of the adhesive conditions is carried out in order to bring the car to a limit state at a "safe" speed. The limit state is skidding of the vehicle [3]. Safe speed is the speed at which there is no risk of injury to persons in the vehicle or serious damage to the vehicle and other equipment in the event of an accident [9].…”

“…This is precisely the factor that will change significantly for the electric installation. Heavy batteries, which are most often placed in place of the original fuel tank and that occupy a larger part of the luggage compartment of the car [1][2][3], have a major influence on the change. This moves the center of gravity of the car closer to the rear axle [3] and makes the vehicle more susceptible to oversteer in terms of vehicle stability.…”

Optimization of device allowing variation of adhesion force for road vehicle testing at safe speed

“…As an accessory for simulating adhesion conditions, the car can be supplemented with an auxiliary frame with supporting wheel units. It is similar to a commercially available device called SkidCar [7]. Since the cross bars extend over the width of the car, i.e.…”

“…The current form of the frame was designed so that its construction was as simple as possible in production and the weight was not considered in the actual design. Thus, it is clear that the entire Alternative SkidCar (ASC) system [6][7][8] is oversized in terms of strength and, above all, material. Design proposals for optimizing the frame have already taken place.…”

“…Depending on the lifting of the supporting wheels, the car is raised and thus the radial reaction transmitted by the car wheels is reduced. Since it is an additional device, it is desirable that this device affects the parameters as little as possible, ideally not at all [6][7][8].…”