Abstract
The improvement of safety of Powered Two Wheelers (PTWs) is one of the most important issues of light transport. So far automatic systems for the improvement of safety have been introduced only in some top class motorcycles. One of the reasons of this retard is the need of expensive and sometimes risky tests. The interaction between the rider and the safety device is very important in PTWs, because the rider’s feeling of the vehicle influences the riding style and the movements of rider’s body strongly influence the dynamic response of the system. Therefore, the numerical simulation of the PTWs with a rider model does not give satisfactory results in terms of man-vehicle interaction. Nowadays the development of virtual reality techniques makes it possible to perform man-in-the-loop simulations, with the possibility of predicting man-vehicle interaction.
This paper deals with a research program aimed to develop a traction control system making use of motorcycle riding simulator SafeBike.
SafeBike simulator has been recently developed by Motorcycle Dynamics Research Group of Padova University. It consists of a mock motorcycle with 5 controlled axes, a sensor system that monitors the rider’s actions and some devices for the generation of the virtual environment (wide screen, scenarios, engine noise reproduction). In the framework of this research some traction control systems have been implemented in the software that simulates the motorcycle.
The first step has been the implementation of the simple traction control (STC). With this control scheme the throttle valve is automatically closed if the longitudinal slip of the rear wheel exceeds a fixed threshold, the level of closure is proportional to the slip. The STC has been tested by means of the simulator in a virtual straight path 1000 m long starting from a standing start. Results show the validity of virtual testing and point out that STC, when the adherence is lower than 0.5-0.6, gives significant advantages in terms of elapsed time, end speed and reduction in motorcycle oscillations.
To improve further the performance, several solutions have been devised and tested by means of the simulator. This process has led to the definition of an Advanced Traction Control (AdvTC). In this control scheme a comparison is made between a slip target and the actual slip and a reference torque is calculated that make it possible to reach the slip target. The engine torque is cut only if it is larger than the reference torque
Keywords: simulator, motorcycle, traction control, safety, man-in–the-loop..