采用全联热-机械有限元模型计算盘式制动器尖叫声的预测工具 (A Predictive Tool to Evaluate Disk Brake Squeal Using A Fully Coupled Thermo--Mechanical Finite Element Model)

This paper presents a new integrated approach to the analysis of brake squeal modelling．It focuses on developing a validated thermo—mechanical finite element model by taking full account of the effect of thermal loading on the structural response of the brake．An integrated study involving time—dependent non—linear contact and a fully coupled transient thermal analysis are carried out to provide the contact and temperature distribution within the brake before executing an instability study using the complex eigenvalue technique．The results，in turn demonstrate the fugitive nature of brake squeal through the system eigenvalues that are extracted throughout the braking period. (摘要: 本文提出一个制动器尖叫模拟的新的综合方法, 它集中开发采用全考虑制动器结构响应热.负荷的影响的正确的热-机械有限元模型. 该综合研究包括实现与时间有关的非线性接触和全联.瞬态热分析, 在进行不稳定研究前, 采用复杂固有值技术, 提供在制动器内的接触和温度分布. 其结果依次通过制动全部系统固有值证实制动尖叫性质的变化.

Development of Vehicle Blind Spot System for Passenger Car

Blind spot of a passenger car is an area around the vehicle that cannot be seen while looking either forward or through side or rear view mirror. In this paper, a blind spot system known as ZRT Vehicle Blind Spot System (ZRT-VBSS) has been developed using Arduino and ultrasonic sensors to overcome the problem. The system is capable to detect a moving vehicle in blind spot area under three main condition of which static, dynamic speed operation at 60 and 100 km/h and also overtake position. The results from the experimental investigation show that ZRT-VBSS is capable to perform at various operating condition that make it reliable to provide solution for driver to overcome the blind spot phenomenon

An Information-Theoretic Measure For Face Recognition: Comparison With Structural Similarity

Automatic recognition of people faces is a challenging problem that has received significant attention from signal processing researchers in recent years. This is due to its several applications in different fields, including security and forensic analysis. Despite this attention, face recognition is still one among the most challenging problems. Up to this moment, there is no technique that provides a reliable solution to all situations. In this paper a novel technique for face recognition is presented. This technique, which is called ISSIM, is derived from our recently published information - theoretic similarity measure HSSIM, which was based on joint histogram. Face recognition with ISSIM is still based on joint histogram of a test image and a database images. Performance evaluation was performed on MATLAB using part of the well-known AT&T image database that consists of 49 face images, from which seven subjects are chosen, and for each subject seven views (poses) are chosen with different facial expressions. The goal of this paper is to present a simplified approach for face recognition that may work in real-time environments. Performance of our information - theoretic face recognition method (ISSIM) has been demonstrated experimentally and is shown to outperform the well-known, statistical-based method (SSIM)

A NEW METHOD IN THE IDENTIFICATION OF NOISE AND VIBRATION CHARACTERISTICS OF AUTOMOTIVE DISK BRAKES IN THE LOW FREQUENCY DOMAIN

Noise and vibration characterization is an important benchmark to reduce brake noise.Brake noise and vibration measurement is commonly done on an actual vehicle or on a brake dynamometer. A full scale brake dynamometer takes into account the attached mass which resembles the mass of a quarter scale vehicle. This paper proposes a testing method which eliminates the need for attached masses. This is achieved through the scaling of the brake system parameters to accommodate the loss of mass and produce similar conditions to those in actual braking. The measurement of noise and vibration is measured simultaneously and an FFT is performed to identify the frequencies of noise and vibration. An experimental modal analysis (EMA)is done to obtain the frequencies which the brake system tends to produce as a validation to the proposed method. It is shown that through this method the noise and vibration characteristics of the brake system and the unstable frequencies can be identified

An information-theoretic image quality measure: Comparison with statistical similarity

We present an information-theoretic approach for structural similarity for assessing gray scale image quality. The structural similarity measure SSIM, proposed in 2004, has been successflly used and verfied. SSIM is based on statistical similarity between the two images. However, SSIM can produce confusing results in some cases where it may give a non-trivial amount of similarity for two different images. Also, SSIM cannot perform well (in detecting similarity or dissimilarity) at low peak signal to noise ratio (PSNR). In this study, we present a novel image similarity measure, HSSIM, by using information - theoretic technique based on joint histogram. The proposed method has been tested under Gaussian noise. Simulation results show that the proposed measure HSSIM outperforms statistical similarity SSIM by ability to detect similarity under very low PSNR. The average difference is about 20dB

A Parallel Study of Vibration Analysis and Acoustic Analysis in Low Frequency Brake Noise

An acoustic analysis in the investigation of brake noise shows the severity of the noise and its characteristics and a vibration analysis shows the excitation of noise that is present in the braking event. In this study, vibration and acoustic analyses were used to study the brake noise which is produced during braking. Vibration and acoustic data were collected simultaneously during braking to identify the braking condition. The data analysis focuses on the low frequency domain. The Fast Fourier method was used to analyse the vibration and acoustic signals. The computation of FFT was done independently and the frequency domains obtained were compared. The parallelism in the analysis was used to identify the acoustic source. The determination of the source will aid in brake noise reduction efforts and reinforce the vibration analysis method as a system identification method for brake noise

An Analytical Model to Identify Brake System Vibration within the Low Frequency Domain

This paper presents the analytical model of a brake system to investigate the low frequency vibration. The purpose of this study is to model and validate brake system vibration. The brake model was developed by applying the theory of sinusoidal traveling waves and wave super positioning. An experimental modal analysis (EMA) of the brake disc has been carried out to obtain the natural frequencies. Wave equations were then formulated based on the experimental data. These waves are super positioned to be shown as a single spatial and temporal function that will provide periodic excitation to the brake pad. The brake pad was modeled as a beam element with distributed friction force. The differential equations were solved using Green's dynamic formulation. The model is capable of predicting vibration behavior of the brake pad for whole range below 1 kHz which has shown strong agreement with the experimental results validated through in-house brake dynamometer. This brake model can serve as a tool to investigate the relationship between braking parameters and other variables within the brake system

Finite Element Analysis on Brake Disc of an Educational All-Terrain-Vehicle

All-terrain vehicle is famously used for various purposes such as in civilian and military.The use of finite element analysis in a preliminary design stage has been demonstrated to be cost and time effective. In this paper, the finite element analysis of a brake disc for All-Terrain-Vehicle (ATV) is demonstrated. Eulerian-Lagrangian method was employed in this work where simple annular ring was used as the disc model. This study is limited to thermal and contact analysis between the disc and brake pad. The results in term of temperature and stresses distribution is obtained and presented. Moreover, the lateral displacement of the disc due to the friction contact is also shown. These results are then used to as a technical guideline in designing brake system for a fully customized ATV

Identification of Intelligent Controls in Developing Anti-Lock Braking System

This paper presents about the development of an Antilock Braking System (ABS) using quarter vehicle model and a control structure is developed to represents an ABS and conventional braking model. Different type of controllers is proposed to develop the ABS model. Antilock braking system (ABS) is an important part in vehicle system to produce additional safety for driver. This system is known as one of the automobile’s active safety. In general, Antilock braking systems have been developed to reduce tendency for wheel lock and improve vehicle control during sudden braking especially on slippery road surfaces. In this paper, to deal with the strong nonlinearity in the design of ABS controller, an intelligent controller has been identified. The controllers such as PID and Fuzzy Logic are proposed to control the stopping distance and longitudinal slip of the wheel. Comparison results between these two controllers generated using Matlab SIMULINK

Design and Development of Amphibious Hybrid Vehicle Body Structure

Amphibious vehicle is a concept of vehicle that can be put forward for the purpose of commercialization, especially in the field of military and rescue operation. This paper present the development process involve in developing the composite bodywork of the Amphibious Hybrid Vehicle (AHV). It involves the process of design followed with the fabrication process. The total design method is used during the selection of the design stage and transformed into 2-dimensional and 3-dimensional form using CATIA V5 software. Upon completion of design, the fabrication process is implemented to complete the bodywork of the amphibious vehicle