Evaluation of Cycling Safety and Comfort in Bad Weather and Surface Conditions Using an Instrumented Bicycle

Understanding how vulnerable road users (cyclists and pedestrians) behave enables the construction of better roadways with adapted geometric and surface design which leads to improve cycling safety and comfort. This study examines the behavior of cyclists using an instrumented city bicycle that allows collecting exact data about bicycle dynamics, trajectory, and speed, as well as essential information to study the behavior of the cyclists, their reaction to the different features of the road surface and geometric design, and their interaction with other road users such as pedestrians, vehicles and other cyclists. 22 cyclists participated in an experiment following a predetermined route in Stockholm, Sweden. The route consisted of a circuit with different types of cycling facilities in order to study the different interactions (cyclist-car and cyclist-pedestrian), the circuit was divided into 3 zones: the first is mixed traffic, the second is a separate cycling lane and the third is shared pedestrian-cycling path. The results show significant data to evaluate cycling safety and comfort in snowy weather conditions and the perception-reaction behavior of cyclists; accordingly, the infrastructure-related risks were evaluated from subjective and objective points of view. In this paper, we propose a new concept to evaluate cycling behavior. This concept allows us to evaluate cyclists’ behavior through the calculation of Behavioral Risk Indicator (BRI) based on different risk factors owing to weather, road and traffic conditions, interaction with other road users and reaction to infrastructure drawbacks. The applications of the proposed concept allow us to evaluate the risks caused by multiple traffic factors and infrastructural drawbacks and study cyclist–bicycle–road interactions and their influences on cycling safety. In addition, the concept provides a new foundation for establishing cycling safety measures that could be applied to improve the infrastructure and reduce traffic accidents in order to attract more people to ride bicycles

Kinematic Optimization of Energy Extraction Efficiency for Flapping Airfoil by using Response Surface Method and Genetic Algorithm

In this paper, numerical simulations have been performed to study the performance of a single fully activated flapping wing serving as energy harvester. The aims of the paper are predicting and maximizing the energy extraction efficiency by using optimization methodology. The metamodeling and the genetic algorithms are applied in order to find the optimal configuration improving the efficiency. A response surface method (RSM) based on Box–Behnken experimental design and genetic algorithm has been chosen to solve this problem. Three optimization factors have been manipulated, i.e. the dimensionless heaving amplitude h0, the pitching amplitude θ0 and the flapping frequency f. The ANSYS FLUENT 14 commercial software has been used to compute the governing flow equations at a Reynolds number of 1100, while the flapping movement combined from heaving and pitching of the NACA0015 foil has been carried out by using an in house user-defined function (UDF). A maximum predicted efficiency of 34.02% has been obtained with high accuracy of optimal kinematic factors of dimensionless heaving amplitude around the chord, high pitching amplitude and low flapping frequency of 0.304 hertz. Results have also showed that the interaction effect between optimization factors is important and the quadratic effect of the frequency is strong confirming the great potential of the applied optimization methodology

Deductive verification of distributed groupware systems

Abstract. Distributed groupware systems consist of a group of users manipulating a shared object (like a text document, a filesystem, etc). Operational Transformation (OT) algorithms are applied for achieving convergence in these systems. However, the design of such algorithms is a difficult and error-prone activity, since building the correct operations for maintaining good convergence properties of the local copies requires examining a large number of situations. In this paper, we present the modelling and deductive verification of OT algorithms with algebraic specifications. We show that many OT algorithms in the literature do not satisfy convergence properties unlike what was stated by their authors.

Development and validation of a powertrain model for low-cost driving simulators

The presented low-cost driving simulator designed and built in LEPSiS (Laboratory for road Operations, Perception, Simulators and Simulations) is specialized in the reproduction of the yaw angle. In order to simulate the vehicle behaviour in real time, a vehicle model has been written in Matlab/Simulink. The algorithm has been developed into independent sub-models to allow for easy replacement and upgrades. During the present research, the upgraded sub-models are the ones concerning the powertrain of the vehicle: starting from the driver commands up to the torque on the transmission shaft. The simulated vehicle and the instrumented vehicle owned by the laboratory are both a Peugeot 406. The control of the movements actually reproduced by the simulator is carried out by means of sensors, placed under the driver seat. A triaxial accelerometer, a triaxial gyrometer and a laser distance-meter have been installed. They are controlled by a MicroAutoBox data acquisition system. Results from the model have been validated using a simulator software, Prosper/Callas by Oktal, on which a virtual model of the Peugeot 406 has been created. In order to compare the outputs, the same manoeuvres performed on the driving simulator have been reproduced on Prosper

Development and validation of a powertrain model for low-cost driving simulators

The presented low-cost driving simulator designed and built in LEPSiS (Laboratory for road Operations, Perception, Simulators and Simulations) is specialized in the reproduction of the yaw angle. In order to simulate the vehicle behaviour in real time, a vehicle model has been written in Matlab/Simulink. The algorithm has been developed into independent sub-models to allow for easy replacement and upgrades. During the present research, the upgraded sub-models are the ones concerning the powertrain of the vehicle: starting from the driver commands up to the torque on the transmission shaft. The simulated vehicle and the instrumented vehicle owned by the laboratory are both a Peugeot 406. The control ofthe movements actually reproduced by the simulator is carried out by means of sensors, placed under the driver seat. A triaxial accelerometer, a triaxial gyrometer and a laser distance-meter have been installed. They are controlled by a MicroAutoBox data acquisition system. Results from the model have been validated using a simulator software, Prosper/Callas by Oktal, on which a virtual model of the Peugeot 406 has been created. In order to compare the outputs, the same manoeuvres performed on the driving simulator have been reproduced on Prosper

Adaptive Observers and Estimation of the Road Profile

ABSTRACT In this paper, we present an adaptive observer to estimate the unknown parameters of a vehicle. The system unknown inputs, representing the road profile variations, are estimated using sliding mode observers. First, we present some results related to the validation of a full car modelization, by means of comparisons between simulations results and experimental measurements (coming from a Peugeot 406 as a test car). Because, we don't know exactly pneumatic parameters and because these parameters can be changed, an other sliding mode observer is developed to estimate the longitudinal forces (which depend on these parameters) acting on the wheels. The estimated Road Profile is compared to the measured one coming from the LPA (longitudinal profile analyser ) in order to test the robustness of our approach

Effects of Wing-Cuff on NACA 23015 Aerodynamic Performances

The main subject of this work is the numerical study control of flow separation on a NACA 23015 airfoil by using wing cuff. This last is a leading edge modification done to the wing. The modification consists of a slight extension of the chord on the outboard section of the wings. Different numerical cases are considered for the baseline and modified airfoil NACA 23015 according at different angle of incidence. The turbulence is modeled by two equations k-epsilon model. The results of this numerical investigation showed several benefits of the wing cuff compared with a conventional airfoil and an agreement is observed between the experimental data and the present study. The most intriguing result of this research is the capability for wing cuff to perform short take-offs and landings