• International Journal of Fuzzy Logic and Intelligent Systems
• /
• v.3 no.2
• /
• pp.166-172
• /
• 2003

The dynamics of the DDWMR depends on the velocity difference of the two driving wheels. And which is known as a type of non-holonomic equation. By this reason, the treatment of DDWMR had become difficult and conservative. In this paper, the differential-driving wheeled mobile robot is considered. The Takaki-Surgeno fuzzy model and a control method for DDWMR is presented. The suggested controller has three control elements. The first element is fuzzy state feedback designed for eliminating the dependence of time-varying parameter. The second element is weighting controller which is designed for good frequency response. The third controller is PI-controller which is designed for good command following and robustness with un-modeled dynamics. In order for achieving the performance objective, the design of controller is based on the loop-shaping algorithm.

• Proceedings of the KSME Conference
• /
• 2004.04a
• /
• pp.858-863
• /
• 2004

In this study, the new prosthetic hand which can perform sensory feedback is developed. Although the continuous development of current prosthetic hands, they have some drawbacks. The drawbacks are the low grasping capabilities, the lack of sensory information given to the user, and so on. Despite the improvement of the function of fingers, the sensory information problem still remains undeveloped. By using differential gear and underactuated mechanical design, it can be solved with the minimum additional weight. And it will be applied to all of the prosthetic hands.

• Journal of the Korean Institute of Telematics and Electronics C
• /
• v.34C no.6
• /
• pp.51-57
• /
• 1997

Low-voltage, low-power gm-C filter utilizing newly dveloped operational transconductance amplifier (OTA) is described in this paper. The OTA has only two MOS transistors in saturation region between $V_{DD}$ and GND, and thus low voltage operation is possible. To improve the linearity, the OTA is made differential. Common mode feedback, essential in differential circuit, requires no additional implemented in $0.8\mu\textrm{m}$ CMOS process, and the center frequency can be controlled from 15MHz with 3.0V single power supply.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.28 no.10
• /
• pp.832-835
• /
• 2017

In this paper, V-band differential low noise amplifier(LNA) using 65-nm CMOS process for high speed wireless data communication is presented. The LNA is composed of 3-stage common-source differential amplifiers with neutralization of feedback capacitances using MOS capacitors and impedance matching utilizing transformers. The fabricated LNA has a peak gain of 23 dB at 63 GHz and 3 dB bandwidth of 6 GHz. The chip area of LNA is $0.3mm^2$ and the LNA consumes 32 mW DC power from 1.2 V supply voltage.

• Journal of Power Electronics
• /
• v.16 no.5
• /
• pp.1629-1638
• /
• 2016

Differential power processing (DPP) systems are among the most effective architectures for photovoltaic (PV) power systems because they are highly efficient as a result of their distributed local maximum power point tracking ability, which allows the fractional processing of the total generated power. However, DPP systems require a high-efficiency, high step-up/down bidirectional converter with broad operating ranges and galvanic isolation. This study proposes a single, magnetic, high-efficiency, high step-up/down bidirectional DC-DC converter. The proposed converter is composed of a bidirectional flyback and a bidirectional isolated switched-capacitor cell, which are competitively cheap. The output terminals of the flyback converter and switched-capacitor cell are connected in series to obtain the voltage step-up. In the reverse power flow, the converter reciprocally operates with high efficiency across a broad operating range because it uses hard switching instead of soft switching. The proposed topology achieves a genuine on-off interleaved energy transfer at the transformer core and windings, thus providing an excellent utilization ratio. The dynamic characteristics of the converter are analyzed for the controller design. Finally, a 240 W hardware prototype is constructed to demonstrate the operation of the bidirectional converter under a current feedback control loop. To improve the efficiency of a PV system, the maximum power point tracking method is applied to the proposed converter.

• Journal of Power Electronics
• /
• v.18 no.1
• /
• pp.92-102
• /
• 2018

A sliding mode control (SMC) for servo motors based on the differential evolution (DE) algorithm, called DE-SMC, is proposed in this study. The parameters of SMC should be designed exactly to improve the robustness, realize the precision positioning, and reduce the steady-state speed error of the servo drive. The main parameters of SMC are optimized using the DE algorithm according to the speed feedback information of the servo motor. The most significant influence factor of the DE algorithm is optimization iteration. A suitable iteration can be achieved by the tested optimization process profile of the main parameters of SMC. Once the parameters of SMC are optimized under a convergent iteration, the system realizes the given performance indices within the shortest time. The experiment indicates that the robustness of the system is improved, and the dynamic and steady performance achieves the given performance indices under a convergent iteration when motor parameters mismatch and load disturbance is added. Moreover, the suitable iteration effectively mitigates the low-speed crawling phenomenon in the system. The correctness and effectiveness of DE-SMC are verified through the experiment.

• ETRI Journal
• /
• v.29 no.6
• /
• pp.835-837
• /
• 2007

A multi-bit sigma-delta modulator architecture is described for low-distortion performance and a high-speed operation. The proposed architecture uses both a delayed code and a delayed differential code of analog-to-digital converter in the feedback path, thereby suppressing signal components in the integrators and relaxing the timing requirement of the analog-to-digital converter and the scrambler logic. Implemented by a 0.13 ${\mu}m$ CMOS process, the sigma-delta modulator achieves high linearity. The measured spurious-free dynamic range is 89.1 dB for -6 dBFS input signal.

• 제어로봇시스템학회:학술대회논문집
• /
• 1992.10b
• /
• pp.219-224
• /
• 1992

This paper deals with the linear quadratic optimal regulator problem for descriptor systems without performing a preliminary transformation for a descriptor system. We derive a generalized Riccati differential equation (GRDE) based on the two-point boundary value problem for a Hamiltonian equation. We then obtain an optimal feedback control and the optimal cost in terms of the solution of GRE. A simple example is included.

• Proceedings of the IEEK Conference
• /
• 2003.07a
• /
• pp.617-620
• /
• 2003

In this paper, a monolithic VCO has been designed for Wireless Local Area Network(WLAN) applications. The differential form VCO is constructed using positive feedback with capacitor and phase shift for low phase noise performance. The VCO shows the phase noise of -92.725 dBc/Hz at an offset frequency of 10KHz and the tunning range of 5.822~6.154GHz.

• 한국디지털정책학회:학술대회논문집
• /
• 2003.12a
• /
• pp.403-415
• /
• 2003

This study is performed to examine the relationships between trust and antecedents in cyberspace. Trust is the major control system in cyberspace. Different time, different spaces, different cultures, indistinct boundaries, flexible structure, separation of information from matters, cybernetics, difficulty of control are differential characteristics between cyberspace and physical space. Providing fit information, use of effective electronic channels, previous trust management, feedback system about output, flexible culture, self-regulation, off-line meeting, providing information about tasks and roles, ability, and justice are supposed to have effects on trust in cyberspace. By electronic mediated systems, the company will have more business opportunity. But trust will be conditional factors of expanding business in cyberspace.