Songsuwankit, Kanoknuch
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Songsuwankit, Kanoknuch
Alternative Name
Songsuwankit, K.
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kanoknuch.so@kmitl.ac.th
17 results
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Item type:Publication, Linear Variable Differential Transformer Signal Conditioning Circuit Based on Phase-Locked LoopThe purpose of this paper is to propose a novel technique for extracting the position signal from an inductive displacement transducer named a linear variable differential transformer (LVDT). In general, the movement of the LVDT core causes its primary inductance change in linear form. The primary winding of the LVDT is used as a time-dependent element for the triangular and square wave generator, which can be called self-oscillation, to generate frequency. The advantage of the proposed technique is that it can measure the displacement using the LVDT without an external oscillator. The change in primary inductance causes the frequency deviation generated by the oscillator. The deviated frequency is captured and converted into a voltage signal using the principle of the phase-locked loop. All the components used in this study are commercially available. The merits of this proposed technique are simple configuration, small size, and low cost. Moreover, the operating range of the LVDT can be extended without the limitation of the nonlinear transfer characteristic. The performance of the proposed technique is discussed in detail and confirmed by experimental implementation. Experimental results show that the maximum error from the proposed technique is about 0.42% and the operating range of the LVDT can be extended to more than 200%. It can be seen that the proposed technique is suitable for embedded measurement in small or micro robots. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Simple LVDT signal to DC converter(2017-02-18); ; A simple technique to produce a linear signal from a displacement transducer, linear variable differential transformer (LVDT), is introduced in this paper. The two-quadrant divider is used to precede the ratio of a different and sum of the two winding signals from the LVDT instead of a four-quadrant divider of a recent approach. The two- quadrant divider is obtained by an operational transcondutance amplifier (OTA) in the form of a voltage-tocurrent converter. The signal from the divider is held by the sample and hold circuit (SHC) controlled by the peak-amplitude finder. As a result, the held signal is achieved without using a low-pass filter. The temperature effect of both OTA and LVDT are compensated. The merit of the proposed technique is that the circuit requires without the low-pass filter. Therefore, the fast response is obtained. The performance of the proposed scheme is confirmed by the experimental results using commercial devices. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Linear range extension for LVDT using analog lookup table(2018-08-13); ; A technique to extend the operating range of the linear variable differential transformer (LVDT) is presented in this article. The realization method is based on the analog lookup table achieved by the ramp signal generator where the frequency of ramp signal is equal to the excitation frequency. Therefore, the resolution of the resulting signal is very high. The output signals of the LVDT are provided to generate the reference signal to synchronize with the ramp signal. The proposed technique can extend the operating range of the LVDT from a normal operating range provided by the specification of the LVDT to maximum stroke range of the LVDT. The circuit of the proposed technique is simple and can be implemented using the commercial devices. The experimental results confirmed that the circuit performance are good agreement with the expected results. The response time of the proposed technique is about two periods of the excitation frequency. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Extension of Linear Operating Range for Linear Variable Differential Transformer Using Its Inverse Transfer CharacteristicAn analog circuit technique to realize an inverse transfer characteristic of a linear variable differential transformer (LVDT) is presented in this paper. Practically, the structure of the LVDT causes a narrow linear operating range compared with its full stroke range. However, a large linear operating range requires a huge structure for the LVDT, making it unsuitable for a small or compact measurement system. The proposed technique can be used in a commercial LVDT to extend the linear operating range to its full stroke range. The technique utilizes an inherent behavior of an operational transconductance amplifier (OTA) to emulate the LVDT transfer characteristic. The LVDT transfer characteristic generated by the OTA is used as a feedback path of the inverting amplifier formed by an operational amplifier (opamp) to realize the inverse transfer characteristic. The residual error due to the OTA behavior is very small and can be neglected without adversely affecting the performance of the proposed technique. All devices used in the proposed scheme are commercially available. The attractive features of the proposed technique are its simple configuration, small size, low cost, and high accuracy. The performance of the proposed technique is discussed in detail and confirmed by its experimental implementation. Measurement results demonstrate that the linear operating range of the commercial LVDT used in this study can be extended by a factor of more than 2.4, and a fullscale percentage error of about 0.068% was obtained. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Temperature Compensation For V/F ConverterIn this article, a method to compensate the temperature effect of voltage to frequency converter (V/F) is presented. Realization technique is based on the use of fre-quency to voltage converter (F/V), which provides the inverse transfer characteristic of V/F converter, in feedback path. The conversion gain of the proposed scheme is identical as a simple V/F converter without effect from feedback con_guration. The frequency derivation due to the change of temperature from 25°C to 60°C can be improved more than 86.4%. Experimental results demonstrated the proposed principle using commercial devices is also included. © 2012 ICIC International. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Low-Cost System for Investigating a Small Motor Fault Classification Based on Current Signal(2025-01-01); ; This research presents low-cost system for motor fault classification. This system uses a microcontroller with built-in ADC and communication capability. The two purposes of this article are to investigate the quality of the system for data acquisition and capability of the system for detecting early motor faults both by microcontroller on the system and personal computer. The embedded software on the system is designed to record current signals from a current sensor, compute FFT-based features and classify the fault based on tinyML method. Data communication between the system and the personal computer can be done by both serial port and TCP socket over Wi-Fi. The performances of the system and the personal computer are compared by the experiment as well as the quality of data recorded from the built-in ADC and a digital oscilloscope. The broken rotor bar and bearing fault in a 2.2kW induction motor are investigated. The classifier used in the experiment is a small feed forward neural network which can be implemented on both the proposed low-cost system and the personal computer. Although the recorded electrical current data by built-in ADC is contaminated with noise, the fault classification on the personal computer yield accuracy up to 90%. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Temperature Compensation for Transformer-type TransducerA novel technique to compensate the temperature effect of a transformer-type transducer is proposed in this paper. The effect of the ambient temperature on the transformer-type transducer is investigated from a primary-winding current. The advantage of the proposed technique is that the temperature effect is compensated without requiring a temperature sensor, making it suitable for applications in robotic and automation systems operated in harsh environments. The primary-winding current of the transducer is generated using a second-generation current conveyor (CCII). The excitation signal of the transformer-type transducer is driven by the CCII and the current flowing through the primary winding is transferred to an output signal of the CCII. The deviation of the primary-winding current due to the temperature effect is evaluated from the output signal of the CCII. The temperature effect on the transducer is manipulated by a closed-loop principle using a subtract-and-sum action instead of a traditional proportional-plusintegral action to eliminate the deviation of the primary-winding current. Therefore, the temperature effect on the transducer is compensated. A linear variable differential transformer (LVDT) is used to demonstrate the proposed technique, whose performance is discussed in detail and confirmed experimentally. All devices used in this experiment are commercially available. Experimental results show that the measured error of the output signal from the LVDT at 70 C can be reduced from 6.2% without temperature compensation to 0.06% by using the proposed technique, which has the advantages of a low cost, simple configuration, and high performance.3 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Electronically adjustable phase shifter using OTAs(2010-12-01); ; First-order phase shifter using operational transconductance amplifiers (OTAs) as active elements is presented in this paper. The corner frequency of the proposed phase shifter can be adjusted by electronic means. The purpose of this paper is emphasized on simple configuration and low cost. The phase response between input and output signals against the operating frequency is varied from 180 to 0 degrees of phase lead. The principle of the proposed circuit is confirmed by simulation and experimental results. To verify the proposed circuit performance, the sinusoidal oscillator is provided for circuit application. ©ICROS.2 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Comparison of Reduced-Length FFT-Based Feature for Induction Motor Fault Classification(2025-01-01); ; This research presents a comparison of FFT-based features which can be used for classifying induction motor faults via neural network. In this paper, the misalignment and rotor bar damage faults are investigated by using stator current as input data only. As the length of the full FFT can include both informative data corresponding to the faults and uninformative data such as noise from environment or electrical supply, only relevant magnitude from FFT bins should be selected and used instead. This paper proposed to use threshold level determined from the magnitude of FFT bins in dataset as a criterion for the selection. From experimental results, an input feature vector created by proposed method can create short input feature vector length to be used by neural network efficiently. The trained neural network performs classification task at 99.98% in accuracy. Comparing to using dimension reduction by PCA, thresholding method needs basic computation, and yields result close to PCA method.3 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Linear-range extension for linear variable differential transformer using triangular signal(2018-12-10); ; This paper presents a linear range extension technique for the linear variable differential transformer (LVDT). The technique is based on a signal conditioning circuit using the analog lookup table, which provides very high resolution of resulting signal. The analog table which is obtained by the triangular signal generator, which has the frequency equal to the excitation frequency. Meanwhile, the referenced signal is obtained by the comparison between the excitation signal and the output signal of LVDT. It is used to synchronize with the triangular signal. The proposed technique is simply circuit configuration and it can be implemented using available commercial devices. The experiment shows that the performances of the proposed circuit can be extended from the normal operating range of LVDT to the maximum stroke range. In addition, the response time of the proposed techniques can be approximated as half period of the excitation signal.2