The paper presents a theoretical framework for the detection and first-level preliminary identification of potential defects on aero-structure components while employing ultrasonic guided wave based structural health monitoring strategies, systems and tools. In particular, we focus our study on ground inspection using laser-Doppler scan of surface velocity field, which can also be partly reconstructed or monitored using point sensors and actuators on-board structurally integrated. Using direct wave field data, we first question the detectability of potential defects of unknown location, size, and detailed features. Defects could be manufacturing defects or variations, which may be acceptable from design and qualification standpoint; however, those may cause significant background signal artifacts in differentiating structure progressive damage or sudden failure like impact-induced damage and fracture.
The evaluation of aircraft characteristics through flight test maneuvers is fundamental to aviation safety and understanding flight attributes. This research project proposes a comprehensive methodology to detect and analyze aircraft maneuvers using full flight data, combining signal processing and machine learning techniques. Leveraging the Wavelet Transform, we unveil intricate temporal details within flight data, uncovering critical time-frequency insights essential for aviation safety. The integration of Long Short-Term Memory (LSTM) models enhances our ability to capture temporal dependencies, surpassing the capabilities of machine learning in isolation. These extracted maneuvers not only aid in safety but also find practical applications in system identification, air-data calibration, and performance analysis, significantly reducing pre-processing time for analysts.
In recent years, the presence of electric buses within public transportation company fleets has significantly increased. To ensure optimal fleet management, it is necessary to analyze vehicle consumption in relation to their operational conditions. This study proposes an analysis of the energy consumption of a full-electric battery bus. Energy consumption was monitored using data made available on the vehicle's CAN network, including data from the main battery and major utilities such as the traction motor, the air conditioning system (both cooling and heating), power steering, main battery chiller, and low-voltage system utilities (lights, ventilation fans, doors opening, etc.). The parameters monitored during the experimentation included the vehicle's position and, consequently, the road gradient, instantaneous vehicle speed, internal and external temperature, vehicle load (to monitor consumption under various load conditions), and the involvement of different drivers.
To ensure adequate visibility without creating excessive glare, vehicle headlights are designed to use a specific source of illumination. The optical designs of headlights gather the luminous flux produced by the light source to produce a useful beam pattern that meets the relevant requirements and standards for vehicle forward lighting. With the advent of solid state, light emitting diode sources for general illumination, an increasing number of LED replacement headlight bulb products has emerged over the past decade. In most cases, these LED replacement bulbs are not permitted for legal use on public roadways, but some countries have begun to permit specific LED replacement bulbs to be used legally on the road for specific makes, models and production years of certain vehicles. If they can be demonstrated to produce a beam pattern that meets the photometric requirements for a legal headlight, they are permitted to be used legally for on-road use.
Recently, with the advancement of autonomous driving technology, the function of external lamps has been changed. Previously, the focus was on the visibility of drivers, but with the advancement of autonomous driving technology, the concept of autonomous driving systems has been developed. Accordingly, the trend of automotive lamp lighting systems has been developed in terms of design, e-HMI (exterior-human machine interface), It is developing in accordance with three major fields such as sensor connection. Therefore, this paper will cover the prior development of road content projection headlamps that enable e-HMI implementation to reflect these new trends. Since the technology is mass-produced and sold by several manufacturers, our company also needs to quickly develop and apply the technology in advance. Only four types of symbols are allowed in European law.
A time domain analysis method of ride comfort and energy dissipation characteristics is proposed for automotive vibration PID control. A two degree of freedom single wheel model for automotive vibration control is established, and the conventional vibration response variables for ride comfort evaluation and the energy consumption vibration response variables for energy dissipation characteristics evaluation are determined. The PID control parameters were tuned using the differential evolution algorithm, and to improve the algorithm's adaptive ability, an adaptive operator was introduced in this article, so that the mutation factor of the differential evolution algorithm can change with the number of iterations. Based on PID control and its parameter tuning, a time-domain solution method for two types of vibration response varaibles, their root mean square values and the average power of energy consumption vibration of automotive vibration PID control is proposed.
Water content estimation is a key problem for studying the PEM fuel cell. When several hundred fuel cells are connected in serial and their active surface area is enlarged for sufficient power, the difference between cells becomes significant with respect to voltage and water content. The voltage of each cell is measurable by the cell voltage monitor (CVM) while it is difficult to estimate water content of the individual. Resistance of the polymer electrolyte membrane is monotonically related to its water content, so that the new online high frequency resistance (HFR) measurement technique is investigated to identify the uniformity of water content between cells and analyze its sensitivity to operating conditions in this paper. Firstly, the accuracy of the proposed technique is experimentally validated to be comparable to that of a commercialized electrochemical impedance spectroscopy (EIS) measurement equipment.
Verification and validation (V&V) of autonomous vehicles (AVs) is a challenging task. AVs must be thoroughly tested, and their safe functionality must be ensured in complex traffic situations and evolving scenarios (including critical cases and rare but safety-relevant events). Furthermore, AVs must mitigate risks and hazards that result from functional insufficiencies, in the absence of technical system failures as described in Safety of the Intended Functionality (SOTIF) standard. SOTIF analysis includes iterative identification of driving scenarios that are not only unsafe, but also unknown. However, identifying SOTIF's unknown-unsafe scenarios is an open challenge. In this paper we propose a systematic approach for identification of unknown-unsafe scenarios, using an optimization method. The proposed approach consists of three main steps including data collection, feature extraction and optimization towards unknown unsafe scenarios.
Recently, fuel cell stacks have been applied to various fields, and the importance of thermal energy management is increasing along with the increase in required power and heat dissipation. In particular, research and development is underway to improve various performance due to FCEV characteristics with a lower cooling temperature than ICE. Therefore, it is essential to develop a new cooling system to overcome these limitations. This study is a prior study to develop the evaporative cooling system by using water as a by-product of the stacks, and aims to identify the effects of variables affecting the performance. The commercial codes were used to simulate the quantitative sprayed area for actual evaluations. The sprayed area was chosen as a key indicator of cooling performance from the viewpoint of evaporation rate, which is well known to be proportional to the evaporation effect on the surface of the fin.