• Journal of Wind Energy
• /
• v.2 no.1
• /
• pp.74-81
• /
• 2011

This paper deals with the application of LQ control to the power curve tracking control of wind turbine. However, two more additional tasks are required to apply the LQR theory to wind turbine control. One is the tracking problem instead of regulation, because the wind turbine is controlled as variable speed and variable pitch. The other is LQ integral control., because the rotor speed should be tightly controlled without any steady state error. Starting from the analysis of wind characteristics, design requirement of a wind turbine control system is defined. A design procedure of LQ tracking with integral control is introduced. The performance of LQ tracking system is analyzed and evaluated by numeric simulation.

• Journal of Biosystems Engineering
• /
• v.37 no.4
• /
• pp.225-232
• /
• 2012

Purpose: Accurate monitoring of information from various agricultural vehicles is one of the most important factors for appropriate management strategy of field operations. While there has been a number of study and design on applications of sensors and actuators for data acquisition and control system in tractor, incompatibility between various customized hardware and software has become a major obstacle to the universal deployment in real field operation. International standard for implementation of electronic control unit (ECU) in agricultural vehicles has becoming a mandatory requirement for inter-operation compatibility in the international trade of agricultural vehicle industries. The ISO 11783 standard is basically based upon well known communication technology designated using the controller area network (CAN) bus. While CAN bus could provide 1.0 Mbps of communication speed, the standard only recommended 250 kbps. Methods: This study presents the implementation and evaluation of ISO 11783 for tractor electronic control units (TECU)with a higher transmission rate from multiple ECU than 250 kbps. Throughput and loss rate of the developed prototype were calculated across manipulated bus load for laboratory experimental tests, and the maximum requirement of transmission rate by ISO 11873 was satisfied with lower than 60% of bus load. Results: Field tests with a TECU implemented to process messages from global positioning system (GPS) receiver resulted that the root mean square error of position information was lower than 4 m with 0.5 m/s as a travelling speed. Conclusions: Results of this study represent the utilization of the international standard ISO 11783 to providepractical developments in terms with the inter-operability of TECU.

• Korean Journal of Veterinary Service
• /
• v.36 no.4
• /
• pp.291-296
• /
• 2013

The purpose of this study was to determine food safety practices and procedures based on Hazard Analysis Critical Control Point (HACCP) system and to suggest more effective method of HACCP implementation in meat packaging industry in Korea. We used the non-compliance rate of each evaluation item to compare the weak points of prerequisite requirements and HACCP. The prerequisite items related to facility, equipment, and tools showed inadequate level of requirements or unsanitary conditions for proper HACCP operation. A lack of understanding of sanitation standard operation procedures was identified as a fundamental barrier to HACCP implementation. High rate of non-compliance in HACCP items compared to prerequisite requirements signify that small businesses have potential difficulties of applying HACCP due to lack of technical expertise, financial resources for prerequisite requirements, and available personnel to prepare and operate HACCP plan. Also we suggest to revise and minimize current critical control points (CCPs). Time-temperature control of cold-storage rooms for carcasses and final products could be performed by control points of prerequisite requirements. As the occurrence frequency getting lower, metal detector should be replaced by intensified training of sanitary handling and safety procedure. This will be more effective and preventive measures against physical contaminants including metal particles. In conclusion, control point of prerequisite requirement may replace CCP in the plant with simple processing line and no heating process such as meat packaging industry.

• Journal of Power Electronics
• /
• v.15 no.4
• /
• pp.1105-1118
• /
• 2015

Battery energy storage devices (ESDs) have become more and more commonplace to maintain the stability of islanded power systems. Considering the limitation in inverter capacity and the requirement of flexibility in the ESD, the droop control was implemented in paralleled ESDs for higher capacity and autonomous operation. Under the conventional droop control, state-of-charge (SoC) errors between paralleled ESDs is inevitable in the discharging operation. Thus, some ESDs cease operation earlier than expected. This paper proposes an adaptive accelerating parameter to improve the performance of the SoC error eliminating droop controller under the constraints of a microgrid. The SoC of a battery ESD is employed in the active power droop coefficient, which could eliminate the SoC error during the discharging process. In addition, to expedite the process of SoC error elimination, an adaptive accelerating parameter is dedicated to weaken the adverse effect of the constraints due to the requirement of the system running. Moreover, the stability and feasibility of the proposed control strategy are confirmed by small-signal analysis. The effectiveness of the control scheme is validated by simulation and experiment results.

• 제어로봇시스템학회:학술대회논문집
• /
• 2003.10a
• /
• pp.113-117
• /
• 2003

The digital systems include the noise in power supply, ground and packaging due to a simultaneous switching of signal, signal reflections and distortions on single and multiple transmission lines. The requirement for the controlled impedance on a PCB can be both a critical success factor and a design challenge. So, the invented tool simulates the tracks controlled impedance with the test coupon. It can saves the design time and supports the economical PCB design.

• Proceedings of the KIPE Conference
• /
• 2001.10a
• /
• pp.117-120
• /
• 2001

Resistance spot welding is widely employed in a manufacturing process. In recent years, the requirement for more sophisticated quality control procedures has been in the mass production industries. The requirements for high productivity and good welding qualities have lead to the development of more widely available microprocessor or computer based control. In this study, the inverter-type power source and welding servo gun are developed.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2004.05a
• /
• pp.248-251
• /
• 2004

This study was performed to propose the minimum thickness of RC slab that satisfies constructibility, fatigue safety, and serviceability requirements such as deflection control. Three different minimum thicknesses are calculated using concrete shear and rebar fatigue formulas, and deflection control, respectively, and checked by constructiblity. The maximum of these three minimum thicknesses is proposed as the minimum thickness of RC slab, which shows that the minimum thickness requirement of RC slab from Korean Bridge Design Code can be thinner than now.

• Proceedings of the KIPE Conference
• /
• 2000.07a
• /
• pp.568-571
• /
• 2000

Resistance spot welding is widely employed in a manufacturing process. In recent years the requirement for more sophisticated quality control procedures has been in the mass production industries. The requirements for high productivity and good welding qualities have lead to the development of more widely available microprocessor or computer based control, In this paper the inverter-type power source and welding servo gun are developed.

• 제어로봇시스템학회:학술대회논문집
• /
• 1993.10a
• /
• pp.613-618
• /
• 1993

This paper presents the aircraft autopilot system with a pre-designed gain schedule. It is mainly consisted of the parameter estimation end the autopilot system design. For off-line parameter estimation, leastsquare methods are investigated. The design of a controller is done in frequenced domain using classical control method and it is designed to satisfy the predetermined requirement such as time constant and transient response. Finally, it is compared with a optimal regulator.

• Proceedings of the IEEK Conference
• /
• 1999.06a
• /
• pp.94-97
• /
• 1999

In this paper, a new real-time neural network connection admission controller is proposed. The proposed controller measures traffic flows, cell loss rate and cell delay periodically each classes. The Neural network learns the relation between those measured information and service quality by real-time. Also the proposed controller uses the DWRR multiplexer with buffer dedicated to every traffic source in order to measure the delay that cells experience in buffer. Experimental result shows that the proposed method can control effectively heterogeneous traffic sources with diverse QoS requirement.