• 한국산업융합학회 논문집
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• 제22권2호
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• pp.137-146
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• 2019

This study proposed a new technique to control of mobile robot based on voice command for (Human-Robot Cooperative operation in manufacturing precess). High performance voice recognition and control system was designed In this paper for smart factory. robust voice recognition is essential for a robot to communicate with people. One of the main problems with voice recognition robots is that robots inevitably effects real environment including with noises. The noise is captured with strong power by the microphones, because the noise sources are closed to the microphones. The signal-to-noise ratio of input voice becomes quite low. However, it is possible to estimate the noise by using information on the robot's own motions and postures, because a type of motion/gesture produces almost the same pattern of noise every time it is performed. In this paper, we describe an robust voice recognition system which can robustly recognize voice by adults and students in noisy environments. It is illustrated by experiments the voice recognition performance of mobile robot placed in a real noisy environment.

• Smart Structures and Systems
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• 제8권1호
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• pp.39-52
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• 2011

We are developing a biomimetic robot based on the Sea Lamprey. The robot consists of a cylindrical electronics bay propelled by an undulatory body axis. Shape memory alloy (SMA) actuators generate propagating flexion waves in five undulatory segments of a polyurethane strip. The behavior of the robot is controlled by an electronic nervous system (ENS) composed of networks of discrete-time map-based neurons and synapses that execute on a digital signal processing chip. Motor neuron action potentials gate power transistors that apply current to the SMA actuators. The ENS consists of a set of segmental central pattern generators (CPGs), modulated by layered command and coordinating neuron networks, that integrate input from exteroceptive sensors including a compass, accelerometers, inclinometers and a short baseline sonar array (SBA). The CPGs instantiate the 3-element hemi-segmental network model established from physiological studies. Anterior and posterior propagating pathways between CPGs mediate intersegmental coordination to generate flexion waves for forward and backward swimming. The command network mediates layered exteroceptive reflexes for homing, primary orientation, and impediment compensation. The SBA allows homing on a sonar beacon by indicating deviations in azimuth and inclination. Inclinometers actuate a bending segment between the hull and undulator to allow climb and dive. Accelerometers can distinguish collisions from impediment to allow compensatory reflexes. Modulatory commands mediate speed control and turning. A SBA communications interface is being developed to allow supervised reactive autonomy.

• 한국통신학회논문지
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• 제30권4A호
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• pp.271-281
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• 2005

본 논문에서는 무선 인터페이스에서 최저의 간섭 레벨을 유지하고 요구된 QoS를 제공하기 위해 사용되는 SIR(signal-to-Interference Ratio) 기반의 폐루프 전력 제어 알고리즘 대신 Soft Symbol을 이용한 Soft Symbol 알고리즘과 함께 병렬 알고리즘을 적용한 폐루프 전력 제어에 대한 연구를 하였다. SIR 기반 알고리즘과 Soft Symbol 기반 알고리즘을 이용한 전력 제어에 대한 성능 평가를 하여 Soft Symbol 기반 알고리즘을 이용한 전력 제어 성능이 향상 되었고, 병렬 알고리즘을 이용한 폐루프 전력 제어에서는 SIR 기반의 전력 제어보다 $15\sim20\%$의 우수한 성능을 보였다.

• 한국항공우주학회지
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• 제37권4호
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• pp.413-418
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• 2009

소형위성 관제용 S대역 프로토타입 트랜스폰더를 상용 부품을 활용하여 설계하였으며, 확장성까지 고려하여 QPSK 변복조 기능을 FPGA를 사용하여 구현하였다. 제작된 트랜스 폰더는 RF Front End, RF 변조기, RF 복조기, 그리고 변복조기로 구성된다. 측정결과 트랜스폰더의 수신 비트오율(이하 BER)은 -105 dBm의 입력전력에서 $1.1{\times}10^{-6}$으로 나타났다. 이러한 방식의 트랜스폰더는 개발기간을 단축할 수 있으며 크기와 무게를 줄일 수 있는 장점이 있다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권3호
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• pp.1377-1399
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• 2020

In search and rescue mission, micro aerial vehicles (MAVs) are typically used to capture image and video from an aerial perspective and transfer the data to the ground station. Because of the power limitation, a cluster of MAVs are required for a large search area, hence an ad-hoc wireless network must be maintained to transfer data more conveniently and fast. However, the unstable link and the intermittent connectivity between the MAVs caused by MAVs' movement may challenge the packet forwarding. This paper proposes a delay tolerant packet forwarding algorithm based on location estimation for MAV networks, called DTN_est algorithm. In the algorithm, ferrying MAVs are used to transmit data between MAVs and the ground station, and the locations of both searching MAVs and ferrying MAVs are estimated to compute the distances between the MAVs and destination. The MAV that is closest to the destination is selected greedy to forward packet. If a MAV cannot find the next hop MAV using the greedy strategy, the packets will be stored and re-forwarded once again in the next time slot. The experiment results show that the proposed DTN_est algorithm outperforms the typical DTN_geo algorithm in terms of packet delivery ratio and average routing hops.

• 한국항공우주학회지
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• 제33권4호
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• pp.100-109
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• 2005

본 논문은 정지궤도 위성의 원격측정명령처리기 성능검증모델의 전자파환경 규격과 시험절차 및 시험결과를 소개한다. 또한 전자파환경시험 동안에 디버깅을 통하여 원격측정 명령처리기에서 발생된 잡음 특성을 평가하였다. 원격측정명령처리기의 전자파양립성 성능은 전력변환기 모듈의 개선을 통해 향상될 수 있다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1994년도 Proceedings of the Korea Automatic Control Conference, 9th (KACC) ; Taejeon, Korea; 17-20 Oct. 1994
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• pp.49-53
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• 1994

Advanced Real-Time Satellite Simulator(ARTSS) has been developed to support the telemetry, tracking and command operations of the ETRI satellite control system and to provide satellite engineers a more powerful and informative satellite simulations tool on the desktop. To provide extensive simulation functions for a communication satellite system in the pre-operational and operational missions, ARTSS uses a geosynchronous orbit(GEO) satellite model consisting of the attitude and orbit control subsystem, the power subsystem, the thermal subsystem, the telemetry, command and ranging subsystem, and the communications payload subsystem. In this paper, the system features and functions are presented and the satellite subsystem models are explained in detail.

• 전력전자학회논문지
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• 제27권6호
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• pp.498-506
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• 2022

This study proposes a design methodology for bidirectional, series-resonant, dual-active bridge (SRDAB) converters. The circuit parameters of the SRDAB converters are designed by considering the output power and efficiency of the converter. The proposed method can be used to design a high-power, high-efficiency SRDAB converter. A voltage controller is employed to manipulate the output voltage of the converter, and the controller gains are selected using the transfer function and frequency response of the controller. Simulation results show that the output power of the designed SRDAB converter is 2 kW per converter module as designed. In addition, the performance of the voltage controller is evaluated using the simulation and experimental results. The output voltage follows the reference voltage within 10 ms under the step change of the reference command. The output voltage also follows the reference voltage under the step load change. The efficiency of the designed SRDAB converter is 95.6%.

• Journal of Power Electronics
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• 제10권6호
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• pp.709-716
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• 2010

MDPS (motor driven power steering) systems have been widely used in vehicles due to their improved fuel efficiency and steering performance when compared to conventional hydraulic steering. However, the reduction of torque ripples and material cost are important issues. A low resolution position sensor for MDPS is one of the candidates for reducing the material costs. However, it may increases the torque ripple due to the current harmonics caused by low resolution encoder signals. In this paper, the torque ripple caused by the quantized rotor position of the low resolution encoder is analyzed. To reduce the torque ripples caused by the quantization of the encoder signals, the rotor position and the speed are estimated by measuring the frequency of the encoder signals. In addition, the compensating q-axis current is added to the current command so that the 6th order torque harmonic is attenuated. The reduction of torque ripples by applying the estimated rotor position and the compensated q-axis current is verified through experimental results.

• 산업공학
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• 제22권3호
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• pp.205-213
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• 2009

Warfare information system is a core factor of future combat operation under NCW(Network centric Warfare) environment. In this paper, we proposed a new MOE(Measure of Effectiveness) that can assess the combat power synergistic effect of warfare information system in the theater-level joint fire operation. This new MOE uses the rule of Newton's second law($F=(m{\Delta}{\upsilon})/{\Delta}t{\Rightarrow}(M{\upsilon}I)/T$). Four factors considered in combat power evaluation are network power(M), movement velocity(v), information superiority(I), command and control time(T). We applied this new MOE to the JFOS-K(Joint Fire Operating System-Korea) to assess its combat power effect and compared with other's effects obtained from different MOE.