Abstract
The aim of the article is to introduce a novel Curve Warning system for motorcycles, which is under development in the SAFERIDER project of the 7th European framework programme. The SAFERIDER project intends to develop advanced rider assistance systems (ARAS) specifically designed for motorcycles. Four warning functions will be developed, among which a Curve Warning. In fact accident analysis indicated that this function has a large potential impact on accident reduction, addressing about 17% of all motorcycle accidents. The project is innovative, since very few on board safety systems exist for motorcycles and almost all are informative only, and quite challenging because PTWs differ from cars in many aspects. Motorcyclists are less prone to accept system that interferes with the motorbike and personal driving style. In addition, motorcycles are intrinsically "unstable" systems and the grip of the tyres is more critical than for cars. In curves, motorcyclists traverse the width of the lanes therefore the knowledge of the optimal trajectory, and the computation of recommendations which accounts for the driver trajectory, is thus mandatory for a system that aims at producing useful and acceptable warnings. ARAS are also technically demanding because, compared to cars, there is much less space to fit sensors and less power source available. In addition motorbikes exhibit large roll angles, which makes it more difficult to estimate the vehicle position in the lane. The Curve Warning function described in this paper addresses the above aspects. It is novel and unique, and based on a holistic approach, which combines road geometry, motorcycle dynamics, rider input and riding styles. The warning strategy is based on the correction of longitudinal dynamics derived from a previewed ideal manoeuvre (reference manoeuvre) continuously computed from the actual state of the PTWs. Warnings are given to the rider via an HMI, which uses a haptic accelerator throttle among the others. In normal driving conditions a fair match between the two is observed and no warning is produced. However, when large differences between actual and ideal accelerations are found the rider is warned to decelerate or brake. As soon as the correct value of deceleration is achieved the warning disappears (which means he will be able to reduce his speed in time to properly negotiate a curve ahead). The article discusses the system HW and SW architecture and the simulator and prototypes integration. It also explains the Curve Warning function concept and implementation showing the first results from riding simulator tests.
KEYWORDS – advanced rider assistance systems, riding simulator, curve warning, optimal preview manoeuvre, motorcycle