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Piezoceramic Transducers Selection Method for High Power Ultrasonic Devices

100%
Kluk P., Milewski A.
Acta Physica Polonica A
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2015
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vol. 127
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issue 3
719-722
EN
A universal method for selecting piezoceramic transducers used in high power ultrasonic devices such as ultrasonic welding and cutting systems has been presented. The key element of such systems is a high power ultrasonic sandwich transducer consisting of a stack of piezoceramic transducers mounted between two masses. Because of relatively large dispersion of piezoceramic transducer parameters between production lots, they must be selected in order to obtain a high quality and long-life sandwich transducer. Presented selection method consists of three stages. First, the parametric identification of the Butterworth-Van Dyke equivalent circuit model is performed based on piezoceramic transducer electrical impedance measurements. Next, the electrical impedance frequency samples are estimated using the identified Butterworth-Van Dyke model. Finally, the k-means clustering algorithm is used to select the best fitted piezoceramic transducer sets.
2
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Efficiency Measurements of Ultrasonic Generator for Welding

100%
Kardyś W., Milewski A.
Acta Physica Polonica A
|
2015
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vol. 128
|
issue 3
456-460
EN
The paper presents results of theoretical analysis as well as practical measurements of efficiency in ultrasonic welding system with main focus on ultrasonic generator. Through analysis and tests were performed using 3 kW 20 kHz Sonic Blaster ultrasonic generator manufactured by ITR. Special equipment was used to perform accurate measurements of input and output power of such generator since an output signal of the ultrasonic generator has high voltage amplitude up to 3 kV and frequency of 20 kHz. Artificial load able to dissipate up to 6 kW of continuous power was designed to simulate ultrasonic transducer. Power measurements were performed on the mains supply of the generator using accurate true RMS power meter and load side measurements were performed using specially built power metering system able to measure high voltage 20 kHz signals based on calibrated high voltage resistive divider and high frequency current transducer.
3
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Structure Optimization of Phase-Coded Sounding Signals

100%
Szczegielniak D., Milewski A.
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|
issue 1
164-167
EN
Pulse compression with a small sidelobe level is one of challenges in designing of modern radar, sonar or ultrasound imaging systems. It may be performed by means of matched filter, that is by correlating the received sounding signal with a stored replica of the transmitted signal. The advantage of the pulse compression method is the increase of the average transmission power while retaining the range resolution corresponding to a short pulse. Phase coding is one of the early techniques for pulse compression of radar signals. Polyphase sequences, which have low sidelobe levels, ensure an easily detectable peak in the output of a matched filter, in other words an easy detection of a received sounding signal. In this paper, an evolutionary algorithm combined with a local optimizer is used to search for polyphase codes with a small sidelobe level of an aperiodic autocorrelation function. The evolutionary algorithm is based on a floating-point representation and the Gaussian mutation is used to produce offspring for the next generation. The self-adaptation mechanism is used to control the mutation operator during the evolutionary process. This research demonstrates that optimization methods can effectively find polyphase sequences with low autocorrelation and seems to be very promising for the future research in area of computer optimization for polyphase codes synthesis.
4
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Structure Optimization of Coded Polyphase Signals with the Enhanced Tolerance to the Doppler Frequency Shift

81%
Szczegielniak D., Milewski A., Szczegielniak M.
Acta Physica Polonica A
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2015
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vol. 128
|
issue 3
452-455
EN
The aim of this research was to verify if It is possible to solve the synthesis problem of polyphase codes efficiently with an acceptable quality in the context of radar applications - with the greatest possible effectiveness of the recognition of such signals in the presence of the noise and occurrence of the Doppler effect. The received results confirmed that the implemented optimization algorithm can search polyphase sequences successfully with a low level of sidelobes and an enhanced tolerance to the Doppler effect. Applying optimization methods allows to form ambiguity function in a measure in the assumed optimization range which seems to be encouraging for future examinations in the field of the computer optimization for the coded radar signals synthesis.
5
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Universal Ultrasonic Generator for Welding

81%
Kardyś W., Milewski A., Kogut P., Kluk P.
Acta Physica Polonica A
|
2013
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vol. 124
|
issue 3
456-458
EN
The paper presents design and parameters of a multifunction ultrasonic generator manufactured by Tele and Radio Research Institute. Efficient usage of ultrasonic welding and cutting technology depends on the ability to precisely control process parameters and tune those parameters to suit particular needs. Ultrasonic generator is responsible for such control and tuning. Presented design incorporates powerful 32 bit Cortex M4 microcontroller with floating point unit which allows using modern signal processing methods to calculate parameters of ultrasonic stack in real time. Calculated parameters, especially impedance of the stack are used to estimate load level and identify phases of the welding process such as melting of the welded material. Precise control of the output signal is possible due to innovative design of the direct digital signal synthesis unit implemented in programmable logic device (CPLD). Resonant inverter topology of the generator front end ensures high electrical efficiency of the device. Designed generator is equipped with various communication interfaces such as USB host and slave, Ethernet, Bluetooth, CAN and RS485. Multiple digital inputs and outputs together with load cell interface, 4-20 mA receiver and 0-10 V analog input enable the generator to monitor and control entire ultrasonic welding system without the need of a PLC unit.
6
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New Multimode Sonotrodes Models Designed for Rotary Ultrasonic Welding Systems

71%
Kogut P., Milewski A., Kardyś W., Kluk P., Gawryś P.
Acta Physica Polonica A
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2013
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vol. 124
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issue 3
474-478
EN
The paper presents methods of designing sonotrodes, working in varied mechanical vibration modes in high power application regime such as rotary ultrasonic welding systems. The aim of the sonotrode design process is to optimize its shape to achieve the best energy efficiency for a given welding process. Sonotrode geometry influences the power transferred to the welded element because it determines the vibration amplitude distribution in the sonotrode. The most popular applications use sonotrodes designed for axial vibration. Conducted research have shown that the optimal displacement and strain distribution is achieved for sonotrodes working in various vibration modes such as axial, transverse, radial or their compositions. In the paper examples of multimode sonotrode models for various rotary ultrasonic welding technologies have been presented.
7
Content available remote

Measurement System for Parameter Estimation and Diagnostic of Ultrasonic Transducers

71%
Kluk P., Milewski A., Kardyś W., Kogut P., Michalski P.
Acta Physica Polonica A
|
2013
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vol. 124
|
issue 3
468-470
EN
The paper presents an architecture and design of measurement system and methods for parameter estimation and diagnostic of ultrasonic transducers used in ultrasonic welding and cutting systems manufactured by Tele and Radio Research Institute. The key element of the ultrasonic welding and cutting system is a high power ultrasonic transducer implemented as a sandwich transducer consisting of a stack of piezoelectric ceramic rings mounted between two masses. High quality welding and cutting demand predetermined frequency characteristic of transducer impedance. Also important are: high energy efficiency, high coupling coefficient, low dielectric loss, and the optimal radiation pattern. In order to manufacture high quality and long-life transducers the piezoelectric rings must be selected and the sandwich transducers diagnosed on the basis of their measured parameters. Presented measurement system takes advantage of the virtual instrument technique in the NI LabVIEW environment. It uses Agilent U2761A Function Generator, U2531A Data Acquisition Unit, and the linear amplifier to measure impedance frequency characteristic in the frequency range of 10 kHz to 100 kHz. Moreover, the system can measure the vibration amplitude in the range of 1 μm up to 100 μm, using an optical sensor, and the temperature of the transducer using a pyrometer sensor.
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