• Energy Research

Intelligent tire concept constitutes one of the approaches to increase the accuracy of active safety systems in vehicle technology. The possibility of detecting tire–road interactions instantaneously has made these systems one of the most important research areas in automotive engineering. This study introduces the use of cost-effective flex and polyvinylidene fluoride strain sensors to estimate some dynamic tire features in free-rolling and real working conditions. The proposed solution combines a microcontroller-based readout circuit for the two sensors with a wireless data transmission system. A suitable prototype was realized and first experimental tests were conducted, in the laboratory as well as on the road. The energy consumption of the wireless monitoring system was optimized. Simulated and experimental results validate the proposed solution.

AbstractThis paper presents an activity concerning the development of a control strategy for power-assisted electric bicycles, also called pedelecs. A common assistance algorithm available on commercial pedelecs consists in providing predefined constant assistance electric power. This approach is lack of flexibility with respect to environmental condition and generally does not provide a good driving comfort. The proposed control method has been designed to minimize the tracking error between the actual bike velocity and the desired one, in the presence of external disturbances. The assistance electric motor torque consists of a feedforward torque integrated with a feedback one. The feedforward contribution is a nonlinear torque based on the pedelec model. The feedback action has the function to compensate the tracking error due to model uncertainties and unknown disturbances. The performance of the methodology has been evaluated applying the controller to an innovative pedelec prototype. To this aim, a mathematical model of the vehicle has been developed. Different human torque models have been implemented in order to study the influence of the rider on the pedelec dynamics. The results of a comparative analysis between the proposed algorithm and a common assistance method have demonstrated that the proposed controller provides improvements in terms of riding comfort and energy utilization.

Abstract This paper describes the methodologies to appraise the power requests and environmental analysis of an electrically assisted bicycle under real driving conditions, also containing regulations and technical-science-related aspects. For this purpose, in this study, the on-road test program of an electrically assisted bicycle was executed in the urban area of Naples on different test tracks, so a general assessment about its driving behavior under several driving conditions was performed. The power requirements in different typical riding situations were estimated by a procedure based on the experimental kinematic parameters that characterize the driving dynamics collected during the real-life applications. An environmental analysis was also performed, with a methodology that takes into account the environmental assessment of a moped by measuring the experimental moped exhaust emissions of the regulated pollutants. Starting from the results acquired during the different test samples, besides, an assessment of the electric traction offered by this pedelec on the driving comfort was evaluated for different riding situations.

AbstractThe paper describes a performance and environmental analysis of an innovative e-bike by means of a dynamic model equipped with a suitable control for the management of the assisted drive of the e-bike.The main advantage of this approach consists of the opportunity to simulate different tracks, e-bikes characterized by different parameters (total mass, wheels moment of inertia) and different control strategies.The authors have also conducted an environmental analysis of the studied vehicle, particularly comparing the e-bike with a thermal moped, in terms of environmental impact.

This paper presents the design of an energy harvesting interface for multiple piezoelectric elements. The latter is targeted to be integrated in an air spring to convert the mechanical energy in electrical one usable to power a wireless sensor node. Modelling of the energy harvesting electronic circuit has been performed to optimize the management of the multiple signals provided by the piezoelectric elements in function of a variable electrical load. An experimental activity has been conducted to validate the circuit design and the tests results demonstrate a good agreement with the numerical ones, confirming the effectiveness of the proposed interface.

A new model of power-assisted bicycle has been designed, set up and tested. The main innovative solutions for the pedelec prototype are described in the present paper: the electric motor position; the new mechanical transmission; the low cost measurement system of the driving torque; the special test rig. Differently from a common approach, in which the electric motor is located on one of the three hubs of the bicycle, the idea of the pedelec prototype consists of an electrical motor in the central position that, by means of a bevel gear, transmits the torque on the central hub. The other innovative solution is represented by the motion transmission from the motor to the pedal shaft, achieved by two different gearboxes: the first one is a planetary gearbox and the second one is a simple bevel gear. The pedelec prototype contains also a new low cost measurement system of the driving torque based on a strain gauge load cell located on one side of the rear wheel, between the hub and the frame. Moreover, a commercial cycling simulator has been suitably modified in order to properly install the different sensors for the measurement of the performance of the pedelec. The test rig is able to reproduce an aforethought route or paths acquired during road tests, to measure the performance of the e-bike in terms of instantaneous power and speed. The experimental test rig can simulate the resistant torque of a predetermined track and it aims to test and to optimize the control strategy available on the electronic control unit. The authors have also conducted an environmental analysis of the developed pedelec, in particular comparing the e-bike with a thermal moped, in terms of environmental impact.