• 전기학회논문지
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• 제65권11호
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• pp.1907-1912
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• 2016

In fact, in order to obtain good performances and low torque ripple, a high-resolution sensor is needed, which is costly and usually needs a special construction for the machine. So researchers are becoming aware of their cost and are exploring the possibility of cost reduction. Information of rotor position is necessary to drive Linear Switched Reluctance Motor(LSRM). Therefore, linear optical encoder is used to detect a mover position. Normally, since the price of encoder, which is used for linear motor is relatively higher than the one used for rotory motor and the cost of additional equipment increases with the length of motor. This is not always appropriate, considering economical efficiency in case of using the linear optical encoder. As a results, LSRM has a great part for the total cost. Therefore, in this paper, we propose LSRM position detecting modeling with reflective type photo-sensor. Additionally, we have investigated the possibility of the reduced position sensor for LSRM drives with advanced control technique. To certify the overall characteristics of the proposed method, a simulation using PSIM software has been carried out and the informative results are displayed.

• 한국정밀공학회지
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• 제19권11호
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• pp.160-166
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• 2002

In this paper, data acquisition and analysis of a measuring machine for marine engine's cams is discussed. A rotary encoder and linear scale of the machine to measure angular and linear displacement respectively are interfaced to the PC via encoder board with 2 channels. The design and measuring data are interpolated by cubic spline curves to compute the precision error which is defined by the maximum and minimum distances between two curves. The minimum zone fit of ISO is employed to evaluate the geometric deviation. The developed system takes only 5 minutes to measure and analyze while the CMM takes over 1 hours even with a skilled operator.

• 센서학회지
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• 제14권4호
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• pp.219-224
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• 2005

In this paper, a contact-type linear encoder-like capacitive displacement sensor (CLECDS) is proposed. It is based on the linear encoder capacitive displacement sensor that consists of two substrates with a series of conducting grating in identical size and it is used as a contact sensor of which the two substrates assembled faced to each other after coated with thin dielectric film. It was confirmed that the prototype of this sensor has resolution of about 126nm and measuring range of 20 mm in the test.

• 전자공학회논문지S
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• 제34S권9호
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• pp.84-90
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• 1997

We proposed a new bit-rate control algorithm to improve MPEG-2 video software encoder. Bit-rate Control plays an improtant role in picture quality of MPEG-2 encoder. To achieve better encoding performance such as controlling picture quality and using bity properly, we proposed a MPEG-2 bit-rate control algorithm using linear average Step-Size. Using a benchmark Program, we compared our algorithm with MPEG-2 Test Model 5. Our proposed algorithm showed better Bit-Rate Control with respect to used bits, picture quality.

• 전기학회논문지
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• 제61권2호
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• pp.298-302
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• 2012

The linear encoder used in the BLAC driving circuit consists usually analog type sensor, and need signal transform from analog sinusoidal to digital one for application in the PWM algorithm that is used to control motor current. When the motor is driven in low speed, it is required many operations and higher quality DSP to convert the hole sensor signal to digital one with enough resolution. In this paper, the another method to convert that signal with enough resolution without calculation of sine function is proposed. This is very simple and have high resolution even if the motor is driving in low speed. To verify the proposed method, BLAC motor is used, and it is proved that the motor is tracking well the reference step signal in the low speed as well as in the high one.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.984-987
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• 2000

In switched reluctance motor(SRM) drive, it is necessary to synchronize the stator phase excitation with the rotor position. Therefore the rotor position information is an essential. Usually optical encoders or resolvers are used to provide the rotor position information. These sensors are expensive and are not suitable for high speed operation. In the paper, the low cost linear encoder suitable for the practical and stable SRM drive is proposed and the control algorithm to provide the switching signals using the simple digital logic circuit is also presented in this paper. It is verified from the experiments that the proposed encoder and logic controller can be a powerful candidate for the practical low cost SRM drive.

• 융복합기술연구소 논문집
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• 제2권1호
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• pp.43-48
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• 2012

Generally, in-plane position of moving object is measured referring to the reference pattern attached to the object. From optical camera to magnetic reluctance probe, there are many ways detecting a variation of the periodical pattern. In this paper, the various operating principles developed for in-plane positioning are reviewed and compared each other. And, a novel method measuring large rotation as well as x, y linear displacements is suggested, including a detailed description of the overall system layout. It is a modified version of the surface encoder, which is a robust digital measuring method. From the surface encoder, the rotation of an object is measured indirectly through a compensated input of optical servo and independently of linear displacements. So, the operating range can be extended simply by enlarging the reference pattern, without magnifying the decoding units.

• Coupled systems mechanics
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• 제5권2호
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• pp.191-201
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• 2016

Coupled structures are widely seen in civil and mechanical engineering. In coupled structures, monitoring the translational motion of its key components is of great importance. For instance, some coupled arms are equipped with a hydraulic piston to provide the stiffness along the piston axial direction. The piston moves back and forth and a distance sensing system is necessary to make sure that the piston is within its stroke limit. The measured motion data also give us insight into how the coupled structure works and provides information for the design optimization. This paper develops two distance sensing systems for coupled structures. The first system measures distance with ultrasonic sensor. It consists of an ultrasonic sensing module, an Arduino interface board and a control computer. The system is then further upgraded to a three-sensor version, which can measure three different sets of distance data at the same time. The three modules are synchronized by the Arduino interface board as well as the self-developed software. Each ultrasonic sensor transmits high frequency ultrasonic waves from its transmitting unit and evaluates the echo received back by the receiving unit. From the measured time interval between sending the signal and receiving the echo, the distance to an object is determined. The second distance sensing system consists of a wire draw encoder, a data collection board and the control computer. Wire draw encoder is an electromechanical device to monitor linear motion by converting a central shaft rotation into electronic pulses of the encoder. Encoder can measure displacement, velocity and acceleration simultaneously and send the measured data to the control computer via the data acquisition board. From experimental results, it is concluded that both the ultrasonic and the wire draw encoder systems can obtain the linear motion of structures in real-time.

• International Journal of Precision Engineering and Manufacturing
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• 제5권4호
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• pp.21-27
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• 2004

In this paper, data acquisition and analysis of a measuring machine for marine engine's cams are discussed. A rotary encoder and linear scale of the machine to measure angular and linear displacement, respectively, are interfaced to the PC via an encoder board with 2 channels. The design and measuring data are interpolated by cubic spline curves to compute the precision error which is defined by the maximum and minimum distances between two curves. The minimum zone fit of ISO is employed to evaluate the geometric deviation. The developed system takes only 5 minutes to measure and analyze the precision error while the CMM takes over I hours even with a skilled operator.

• International Journal of Precision Engineering and Manufacturing
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• 제9권3호
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• pp.82-84
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• 2008

A surface encoder based on the Half-shaded square pattern (HSSP) is presented. The HSSP working as reference grid is composed of the straight lines which are easy to be fabricated and make measuring time short. Since the periodic cell is separated in ON/OFF by the $45^{\circ}$ straight line, the duration from the starting point of scanning to the first rising edge and the duty cycle of the pulse train vary with respect to the position of the starting point. And the relationship between X and Y position and the duration, and duty cycle is described in the simple linear equation. Therefore, it is possible to measure X and Y position with the measured duration and duty cycle without calculating load. Through the test set-up, the feasibility of the proposed surface encoder was verified. Also the future works for improvement of performance were suggested.