• Journal of the Institute of Convergence Signal Processing
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• v.24 no.3
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• pp.172-177
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• 2023

In this paper, 2-dimensional backtracking method for ultrasonic signals. Ultrasonic sensors are a common technology used in industrial fields as many studies have been conducted on distance measurement and indoor location tracking using transmission and reception devices in pairs. A method for tracking a signal of an arbitrary ultrasonic transmission device on a 2D plane using only a receiver of an ultrasonic signal is proposed. In order to track the ultrasonic signal, the receiver receives the signal by making at least three. The three receivers may calculate a direction and a distance using a time difference in which the ultrasound reception sound is reached. The existing method of tracking signal sources using ultrasonic waves has a problem of time synchronization of devices because the transceivers must be paired or installed independently for each sensor. In order to solve this problem, the distance of the ultrasonic receiver is minimized, and it is configured as one device. The sensor installed as one device may be processed by one operator, thereby solving the time synchronization problem. To increase time difference accuracy, high-speed 32-bit timers with high time resolution can be used to quickly calculate and track distances and directions.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.3
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• pp.242-247
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• 2008

As an absolute positioning system, iGS is designed based on ultrasonic signals whose speed can be formulated clearly in terms of time and room temperature, which is utilized for a mobile robot localization. The iGS is composed of an RFID receiver and an ultra-sonic transmitter, where an RFID is designated to synchronize the transmitter and receiver of the ultrasonic signal. The traveling time of the ultrasonic signal has been used to calculate the distance between the iGS system and a beacon which is located at a pre-determined location. This paper suggests an effective operation method of iGS to estimate position of the mobile robot working in unstructured environment. To expand recognition range and to improve accuracy of the system, two strategies are proposed: utilization of beacons belonging to neighboring blocks and removal of the environment-reflected ultrasonic signals. As the results, the ubiquitous localization system based on iGS as a pseudo-satellite system has been developed successfully with a low cost, a high update rate, and relatively high precision.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.1209-1213
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• 1991

This paper describes a new method for performance improvement ultrasonic ranging system using V40 controller. Detectable range of ultrasonic ranging system depends on transducer frequency and bandwidth of the receiver, and damping of the transducer, etc. Conventional ranging systems are somewhat inaccurate because they do not have capability of compensating changes in medium condition. The novel ranging system overcomes this disadvantage by placing in the same medium a dummy sensor functioning as a standard calibrating instrument and by providing data processing capability using V40 controller.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.8 s.197
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• pp.41-49
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• 2007

In this paper, we proposed a new ultrasonic distance measurement system with high accuracy and long range. To improve accuracy and enlarge range, the time of flight of ultrasonic is calculated by the period detecting method. In the proposed ultrasonic distance measurement system, the ultrasonic transmitter and receiver are separated but synchronized by RF(Radio frequency) module. The experiment has been implemented from short distance 1m to maximum available distance 30m. And the period detecting method is compared with the conventional threshold level method. Experimental results show the accuracy and range of the distance measurement are improved by this period detecting method.

• Journal of Ocean Engineering and Technology
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• v.22 no.4
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• pp.8-13
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• 2008

In this study, an investigation of shear wave ultrasonic technique was carried out to detect stacking orientation error for CF/Epoxy quasi-isotropy composite laminates. The ultrasonic shear wave is particularly sensitive to ply orientation and layup sequence in tire CF/Epoxy composite laminates. In the manufacturing of composite laminates, it is important that layup errors be detected in samples. In this work, an effect was mack to develop shear wave techniques that can be applied to composite laminates. During testing, the mast significant problem is that the couplant conditions do not remain the same because of its changing viscosity. The design and use of a shear ware transducer would greatly alleviate the couplant problem. A pyramid of aluminum, with isosceles triangle (two 45o angles) sides, was made to generate shear waves, using two longitudinal transducers based on an ultrasonic-polarized mechanism. A signal splitter was connected to the pulser jack on a pulser/receiver and to the longitudinal transducers. The longitudinal transducers were mounted with mineral oil, and the shear transducer was mounted with burnt honey on the bottom as a receiver. The shear wave was generated at a maximum and a minimum based on the ultrasonic-polarized mechanism. Results show it is feasible to measure layup error using shear wave transducers on a stacking of prepregs in composites.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.529-531
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• 2004

For localization, it is very important for an autonomous mobile robot to be able to recognize indoor environment and match an object it detect to an object within a map developed either online or offline. Given the map defining the locations of geometric beacons like wall and comer existing in the robot operation environment, this paper presents a stereo ultrasonic sensor based method that can be conveniently used in recognizing the geometric beacons. The stereo ultrasonic sensor used in the experiment consists of an ultrasonic transmitter and two ultrasonic receivers placed symmetrically about the transmitter. Experiment shows that the proposed method is more efficient in recognizing wall and coner than the conventional method of using multiple number of transmitter-receiver pairs.

• Journal of the Korean Society of Safety
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• v.17 no.1
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• pp.39-44
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• 2002

This paper shows error in the polarization direction on ultrasonic transducers how sensitive the shear ultrasonic waves are to a little misoriented plies according to the angle variation of shear ultrasonic waves $0{\circ},\;45{\circ}$ and $90{\circ}$. Also, it is shown that shear waves, particularly the transmission mode with the transmitter and receiver perpendicular to cach other, have high sensitivity for detecting anomalies in fiber orientation and ply layup sequence that may occur in the manufacturing of composite laminates. Experimental results are agreed with a modeling solutions which was based on decomposition of shear wave polarization vector as it propagates through the composite laminates. This wave appeared considerably to be sensitive to CFRP composites to thickness direction along in-plane fibers.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.10
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• pp.996-1001
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• 2006

This paper proposes an ultrasonic location system based on the spread spectrum principle. Though there are several conventional ultrasonic systems, the proposed system is the first one that combines spread spectrum and amplitude modulation principles. The proposed ultrasonic location system is advantageous in that it can improve positioning accuracy and detection sensitivity by the spread spectrum principle, it simplifies transmitter and receiver circuits, and it is easy to upgrade its performance by modifying only the software functionalities. By several real data experiments, the advantage and performance of the proposed location system is demonstrated.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.54 no.6
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• pp.366-371
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• 2005

For an autonomous mobile robot localization, it is very important for the robot to be able to recognize indoor environment and match a detected object to an object defined within a map developed either online or of offline. Given the map defining the locations of geometric beacons like wall and corner existing in the robot operation environment, this paper presents a stereo ultrasonic sensor based method practically applicable in recognizing the geometric beacons in real-time. The stereo ultrasonic sensor used in the experiment consists of an ultrasonic transmitter and two ultrasonic receivers placed symmetrically about the transmitter Experimental results are provided to demonstrate that the proposed method is more efficient in recognizing wall and coner than the conventional method of using multiple number of transmitter-receiver pairs.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.63-66
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• 2006

This paper proposes an ultrasonic location system based on the spread spectrum principle. Compared with the existing ultrasonic location systems, the proposed system combines the spread spectrum and amplitude modulation principles. As a result, the proposed ultrasonic location system is advantageous in that it can improve positioning accuracy and detection sensitivity by the spread spectrum principle, it simplifies transmitter and receiver circuits by the amplitude modulation, and it is easy to upgrade its performance by the software functionalities. The advantages and performance of the proposed location system are demonstrated by experiments.