Niccolò Baldanzini

Decision logic of an active braking system for powered two wheelers

Powered two-wheeler (PTW) users are exposed to a high risk of accidents leading to severe injuries and fatalities. The trend of PTW accidents has pointed out the need for an intervention on PTW safety with new and effective solutions. One of the possible answers came from the EC-funded Powered two wheeler Integrated Safety (PISa) project which identified the autonomous braking of the vehicle as one of the most promising safety functions for PTWs. The aim of this paper is to report on the design of the decision logic for deploying a PTW autonomous braking system in case of an imminent collision. Rationales and limitations for this pioneering application are given. The feasibility of the autonomous deceleration is demonstrated by an experimental study conducted with the PISa test bike implementing a prototype of the autonomous braking system, named the Active Braking (AB) system.

Analysis of the minimum swerving distance for the development of a motorcycle autonomous braking system

In the recent years the autonomous emergency brake (AEB) was introduced in the automotive field to mitigate the injury severity in case of unavoidable collisions. A crucial element for the activation of the AEB is to establish when the obstacle is no longer avoidable by lateral evasive maneuvers (swerving). In the present paper a model to compute the minimum swerving distance needed by a powered two-wheeler (PTW) to avoid the collision against a fixed obstacle, named last-second swerving model (Lsw), is proposed. The effectiveness of the model was investigated by an experimental campaign involving 12 volunteers riding a scooter equipped with a prototype autonomous emergency braking, named motorcycle autonomous emergency braking system (MAEB). The tests showed the performance of the model in evasive trajectory computation for different riding styles and fixed obstacles.

Design and testing of a MRF rotational damper for vehicle applications

Adaptive dampers are an interesting solution for conjugating the necessity of controllable devices and low power consumption. Magneto-rheological fluids (MRF) can be profitably employed in adaptive dampers because of the significant variation of fluid parameters with magnetic field properties. This paper focuses on the design process of an innovative rotational MR damper specifically created to be placed in the front-wheel suspension of a compact car. The advantages of the rotational damper and the definition of the optimal design are described. The proposed damper significantly reduces several key problems associated with MR devices: the quantity of fluid required, the sedimentation of ferromagnetic particles in the suspension and the abrasion of the seals. In fact, with this solution, low average working pressure, low flow velocity through valves, a wide range of variable damping characteristics, and high durability of the damper can be achieved. Thanks to this innovative component, different new architectures for adaptive suspension systems can be developed to have a planar distribution of the suspension components with a consequent space optimization and size reduction in the vertical direction.

FE modelling of a motorcycle tyre for full-scale crash simulations

In finite-element (FE) simulations of motorcycle crashes, the tyre behaviour is of utmost importance since the front tyre is often the first component involved in the impact. For this reason, a typical approach used in car crashes analysis is not appropriated. In this paper, the state-of-the-art tyre FE models for crash/impact analysis will be presented and discussed. Two alternative tyre modelling approaches for full-scale virtual crash tests of motorcycles will be proposed and tested. A Design Of Experiment (DOE) analysis is performed to identify the main parameters that influence the model behaviour. The results are used to tune the models, based on experimental data. Finally, the models are compared and the one that results in the best compromise in terms of fidelity and computational efficiency is assessed in an additional set of configurations.

Development and validation of an FE model for motorcycle–car crash test simulations

In the development process of new solutions for rider protection, finite element (FE) simulations of motorcycle to car crashes represent a way to reduce costs and time. This paper focuses on the development and validation of an FE virtual environment for complete crash test scenarios and its use to evaluate the head and neck injuries. Models are validated through comparison of numerical and experimental data and, aiming at performing quantitative analyses, a new approach (named injury rating) for injury evaluation is proposed. The virtual environment is applied, as test case, to the simulation of eight crash scenarios selected from the ISO 13232 standard. The results are presented and discussed to demonstrate the potentialities of the approach in designing new rider protective devices.

New HMI Concept for Motorcycles---The Saferider Approach

For more than one decade the European Commission has been focusing on the enhancement of road safety by funding research on Advanced Driver Assistance Systems (ADAS) and Intelligent Vehicle Information Systems (IVIS) in the field of automotive. However, the application of such technologies in Powered-Two-Wheelers (PTW) is currently lacking behind. While in the automotive sector extended knowledge has been generated also on the Human-Machine Interface (HMI) for ADAS and IVIS this does by far not apply for the PTW sector. This paper presents the SAFERIDER (Advanced telematics for enhancing the safety and comfort of motorcycle riders) project outline and focuses on the new HMI concept and haptic interface devices that are developed within the project.

On the effect of testing uncertainties in the homologation tests of motorcycle helmets according to ECE 22.05

Industrial products designed for a specific task need to prove their capability to fulfil their design goal through experimental homologation procedures. Homologation standards define the necessary steps for these experimental tests in a very detailed manner but still are not entirely capable of accounting for any imprecisions in the definition of the testing procedure and variability in its carrying out. This paper addresses the issue of testing uncertainties that are related to the homologation standard ECE 22.05 for motorcycle helmets. Finite Element simulations are performed in the framework of an uncertainty analysis based on fuzzy-valued testing parameters, which are an adequate and very practicable method to represent the homologation uncertainties. Through the uncertainty analysis, large uncertainties are found for the relevant homologation quantities. They are entirely in agreement with the homologation standards. Moreover, the most important testing parameters are identified and recommendations for improving the homologation standards are formulated.

Real-time estimation of road–tyre adherence for motorcycles

Improving braking skills of a rider supported by a real-time training device embedded in the motorcycle represents a possible strategy to deal with safety issues associated with the use of powered two wheelers. A challenging aspect of the braking trainer system is the evaluation of the adherence between tyre and road surface on each wheel. This paper presents a possible method to evaluate the current and maximum adherence during a braking manoeuvre. The proposed approach was positively validated through multi-body simulations and experimental data acquired in naturalistic riding conditions.

Stochastic BEM for the Vibroacoustic Analysis of Three-Dimensional Structures

Nowadays, extending the NVH prediction reliability to the whole frequency range is an attractive goal of vibroacoustics. Deterministic methodologies are well established for the low-frequency range, but, decreasing the wavelength, energy-based methods are necessary. In such a range, a crucial role is played by small perturbations which highly influence the response sensitivity. Moreover, taking into account these variations allows to make the product design more robust and even quicker. Introducing geometrical uncertainties within the classic BEM formulation allows to obtain the so-called stochastic BEM. As a result, the solution shows deterministic behaviour at low frequencies; decreasing the wavelength, the effect of the uncertainties smooths the response. Consequently, it is possible to obtain an averaged trend over the whole frequency range which asymptotically tends to the deterministic one. In this paper, we deal with three-dimensional acoustic SBEM. First, the formulation and its basic assumptions are presented. Secondly, they are applied to academic cases to show its potentialities in predicting vibroacoustic behaviour over a wide frequency range.

Optimization of the Global Static and Dynamic Performance of a Vehicle Body by Means of Response Surface Models

Concept FE models of the vehicle structure are often used to optimize it in terms of static and dynamic stiffness, as they are parametric and computationally inexpensive. On the other hand they introduce modeling errors with respect to their detailed FE equivalents due to the simplifications made. Even worse, the link between the concept and the detailed FE model can be sometimes lost after optimization.The aim of this paper is to present and validate an alternative optimization approach that uses the detailed FE model of the vehicle body-in-white instead of its concept representation. Structural modifications of this model were applied in two different ways — by local joint modifications and by using mesh morphing techniques. The first choice was motivated by the strong influence of the structural joints on the global vehicle performance. For this type of modification the plate thicknesses of the most influent car body joints were changed. In the second case the overall car dimensions were modified.The drawback of using detailed FE models of the vehicle body is that they can be times bigger than their concept counterparts and can thus require considerably more time for structural analysis. To make the approach proposed in this work a feasible alternative for optimization in the concept phase response surface models were introduced. With them the global static and dynamic performance of the body-in-white was represented by means of approximating polynomials. Optimization on such mathematical models is fast, so the choice of the optimization algorithm is not limited only among local-search strategies.In the current study Genetic Algorithm was used to increase the chances for finding better design alternatives. Two different optimization problems were defined and solved. Their final solutions were presented and compared in terms of structural modifications and resulting responses. The approach in this paper can be successfully used in the concept phase as it is fast and reliable and at the same time it avoids the problems typical for concept models.Copyright