Structural Damage Detection Using Inner Product Vector and Low Pass Filter Technique

2012 ◽  
Vol 204-208 ◽  
pp. 2942-2946 ◽  
Author(s):  
Le Wang ◽  
Zhi Chun Yang

The inner product vector (IPV) was proposed in our previous research as a damage detection algorithm which uses cross correlation functions between vibration responses under band pass white noise excitation. It was verified that the IPV of a structure is a weighted summation of the mode shapes of the structure and the weighing factors for each modes are different. Structural damage detection examples in our previous research shown that the damage location can be correctly detected if the bandwidth of the band pass white noise excitation only covers the fundamental natural frequency of the structure. However, the bandwidth of the band pass white noise excitation may cover first several natural frequencies of the structure in practice. This paper just investigates the damage detection method using IPV under the situation when the bandwidth of the band pass white noise excitation may cover first several natural frequencies of the structure, i.e. the hybrid method using IPV and low pass filter technique. Firstly, the theory of IPVs and the damage detection method using IPV are reviewed shortly. Then, the hybrid method using IPV and low pass filter technique is introduced. Finally, experimental damage detection example of a shear frame structure is presented to illustrate the method proposed in this paper.

Author(s):  
R S Sharp

The article is about steering control of cars by drivers, concentrating on following the lateral profile of the roadway, which is presumed visible ahead of the car. It builds on previously published work, in which it was shown how the driver's preview of the roadway can be combined with the linear dynamics of a simple car to yield a problem of discrete-time optimal-linear-control-theory form. In that work, it was shown how an optimal ‘driver’ of a linear car can convert the path preview sample values, modelled as deriving from a Gaussian white-noise process, into steering wheel displacement commands to cause the car to follow the previewed path with an attractive compromise between precision and ease. Recognizing that real roadway excitation is not so rich in high frequencies as white-noise, a low-pass filter is added to the system. The white-noise sample values are filtered before being seen by the driver. Numerical results are used to show that the optimal preview control is unaltered by the inclusion of the low-pass filter, whereas the feedback control is affected diminishingly as the preview increases. Then, using the established theoretical basis, new results are generated to show time-invariant optimal preview controls for cars and drivers with different layouts and priorities. Tight and loose controls, representing different balances between tracking accuracy and control effort, are calculated and illustrated through simulation. A new performance criterion with handling qualities implications is set up, involving the minimization of the preview distance required. The sensitivities of this distance to variations in the car design parameters are calculated. The influence of additional rear wheel steering is studied from the viewpoint of the preview distance required and the form of the optimal preview gain sequence. Path-following simulations are used to illustrate relatively high-authority and relatively low-authority control strategies, showing manoeuvring well in advance of a turn under appropriate circumstances. The results yield new insights into driver steering control behaviour and vehicle design optimization. The article concludes with a discussion of research in progress aimed at a further improved understanding of how drivers control their vehicles.


2009 ◽  
Vol 18 (07) ◽  
pp. 1287-1308 ◽  
Author(s):  
EMAN A. SOLIMAN ◽  
SOLIMAN A. MAHMOUD

This paper presents different novel CMOS realizations for the differential difference operational floating amplifier (DDOFA). The DDOFA was first introduced in Ref. 1 and was used to realize different analog circuits like integrators, filters and variable gain amplifiers. New CMOS realizations for the DDOFA are introduced in this literature. Furthermore the DDOFA is modified to realize a fully differential current conveyor (FDCC). Novel CMOS realizations of the FDCC are presented. The FDCC is used to realize second-order band pass–low-pass filter. Performance comparisons between the different realizations of the DDOFA and FDCC are given in this literature. PSPICE simulations of the overall proposed circuits are given using 0.25 μm CMOS Technology from TMSC MOSIS model and dual supply voltages of ±1.5 V.


Electronics ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 102
Author(s):  
Noy Citron ◽  
Eldad Holdengreber ◽  
Oz Sorkin ◽  
Shmuel E. Schacham ◽  
Eliyahu Farber

A high-performance S-band down-conversion microstrip mixer, for operation from 77 K to 300 K, is described. The balanced mixer combines a 90 degree hybrid coupler, two Schottky diodes, a band pass filter, and a low pass filter. The coupler phase shift drastically improves noise rejection. The circuit was implemented according to the configuration obtained from extensive simulation results based on electromagnetic analysis. The experimental results agreed well with the simulation results, showing a maximum measured insertion loss of 0.4 dB at 2 GHz. The microstrip mixer can be easily adjusted to different frequency ranges, up to about 50 GHz, through the proper choice of microstrip configuration. This novel S-band cryogenic mixer, implemented without resorting to special components, shows a very high performance at liquid nitrogen temperatures, making this mixer very suitable for high-temperature superconductive applications, such as front-ends.


2020 ◽  
Vol 5 (2) ◽  
pp. 138
Author(s):  
Choirul Huda ◽  
Herman Tolle ◽  
Fitri Utaminingrum

Road damage produces serious problems for the driver such as travel efficiency, vehicle value, and even driver safety. In some cases, road damage causes accidents and ends in death. Currently, road damage detection research extends to grow and present various approaches such as the implementation of an accelerometer sensor. However, the implementations face lacks of accuracy since unable to work in real-time and poor implementation. In the end, the system inadequate to identify damaged roads effectively. Therefore, a comprehensive study was proposed. Firstly, data collection is conducted by applying a low-pass filter to obtain accurate data. The next step is estimating the range value of the accelerometer graph. In the final step, the classification is performed to identify road conditions into smooth, medium and poor. Based on some experiments that have been done, the proposed method accurately recognizes road conditions by 86.67%.


This paper presents a voltage-mode(VM) tunable multifunction inverse filter configuration employing current differencing buffered amplifiers (CDBA). The presented structure utilizes two CDBAs, two/three capacitors and four/five resistors to realize inverse low pass filter (ILPF), inverse high pass filter (IHPF), inverse band pass filter (IBPF), and inverse band reject filter(IBRF) from the same circuit topology by suitable selection(s) of the branch admittances(s). PSPICE simulations have been performed with 0.18µm TSMC CMOS technology to validate the theory. Some sample experimental results have also been provided using off-the-shelf IC AD844 based CDBA.


2014 ◽  
Vol 2014 ◽  
pp. 1-6
Author(s):  
Lanyong Zhang ◽  
Yixuan Du ◽  
Bing Li

Multiple carrier frequency detecting signals are transmitted simultaneously by multiple transmitters in multistatic sonar. The echoes mixed with different carrier frequency in the receiver. The different carrier frequency echoes must be separated from one another before features of echoes are extracted in the receiver. Such a problem can be solved by band-pass and low-pass filters. But the amount of operation by this way is too large for real-time realization. Thus this paper presents the technique of channelized receiver based on multiphase filter and the receiving schemes of echo. The proposed receiver has a smaller amount of operation compared to low-pass filter. At last, the feature extraction technology correlation processing and FDWT are introduced. In order to verify the feasibility of this scheme in multistatic sonar, the extracted features of original echo are contrasted with those of processed echo via simulation. Simulation results show that the proposed receiver provides considerable performance.


2021 ◽  
Author(s):  
Ara Abdulsatar Assim Assim

This paper demonstrates the design and implementation of an inductorless analog band-pass filter (BPF). Band-pass filters are widely used in communication systems, wireless transceivers and audio systems, they only pass signals within a desired frequency range. The principles mentioned in this article can be generalized to design any analog filter regardless of its order, approximation and prototype. The design procedure can be broken down into three main parts, first of all, a passive low-pass filter (LPF) is implemented, then the passive LPF is converted into a passive BPF. Finally, the passive BPF is transformed into an active BPF by adding operational amplifiers. The active BPF is then modified into two different topologies, the first in which the inductors are replaced with simulated- inductors (gyrators), while in the second topology, less operational amplifiers are used. <br>


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