On ultrasonic communication through metal structure for machine embedded sensing

Abstract

With the development of machine embedded sensing, wireless communication through metal structures is becoming a critical issue in manufacturing equipment, process monitoring and control. To address it, this paper presents a multi-carrier ultrasonic communication scheme to achieve high-bit data rate for machine embedded sensing through metal structures. To extract the coded information from ultrasonic signal and denoise the signal, a new signal processing method, named multi-scale enveloping symbolic analysis (MuSEnSA), is also formulated by integrating dual-tree complex wavelet packet transform and symbolic analysis. Dual-tree complex wavelet packet transform (DT-CWPT) is firstly investigated by separating multi-carrier signals under noise contamination, given its properties of shift-invariance and flexible time frequency partitioning. A new envelope extraction and threshold setting strategy for selected wavelet coefficients is then introduced to retrieve the coded digital information by taking advantage of symbolic analysis. Numerical and experimental studies are performed to evaluate the effectiveness of the developed signal processing method for injection molding monitoring.

The effects of scaling and bends in a fiber‐optic modalmetric acoustic detector

“…It is assumed that the phase-shift Δϕ is linearly dependent on the effective interaction length 2L s of the fiber 12 as given by Equation (2).…”

“…When the acoustic amplitude to be detected increases, the output should not be distorted or attenuated. A highly sensitive device is useful for detecting very weak signals that may be suitable as a receiver for typical acoustic communications through metallic media, [1][2][3][4][5][6][7][8] where the ultrasound attenuation is very strong. Nevertheless, input signals of large amplitudes will produce distorted outputs that can be deleterious, even for digital communications using on-off key format.…”

“…Most telecommunication channels use electromagnetic carriers in the radio or optical domains. However, some physical media or applications, such as oil pipelines, 1 machine embedded sensing, 2 structural health monitoring, 3 transmission through metallic walls, 4 transmission through solid channels with various shape, material and size to explore the ultrasonic communication feasibility in diverse environments, 5 and metallic cables or pipes, 6,7 do not support the propagation of electromagnetic carriers. As a result, one may exploit acoustic carriers for data communications along short‐links, for example, telemetry of measurements data.…”

Low-Power Ultrasonic Front End for Cargo Container Monitoring

“…Electromagnetic-acoustic transducers (EMATs) [9,14] and piezoelectric transducers (PTs) [15][16][17][18][19][20][21][22][23][24][25][26] are the most popular devices for this approach. The strength of EMATs lies in their capability of non-contact operation.…”