• Journal of Biosystems Engineering
• /
• v.31 no.1 s.114
• /
• pp.9-15
• /
• 2006

Draft control is key technique in plow control system for automation of implement control system. To make the consistent draft force is an essential factor for preventing the reduction of working efficiency by tractor's slip and also improving the working efficiency. Therefore, the purpose of this study is to develop the draft sensor for draft control of plow and evaluate the usability of the algorithm of draft control system using proportional control valve. The developed draft control system could extract the draft force very well regardless of draft condition, change of setting draft force and response time in the response characteristic test. The maximum draft force at 3-Point linkage was 10,000 N and the deviation of the control system was 125.8 N in steady state condition. The developed control system worked very well with regard to the change of draft force in field and even in soil condition with soil reaction. The results of experiment showed the characteristics of response was sufficient to be used as the implement draft control system for tractor using proportional valve.

• Journal of Biosystems Engineering
• /
• v.14 no.4
• /
• pp.229-241
• /
• 1989

The purposes of this study were to develop an electronic-hydraulic draft control system for tractor implements, to investigate the control performance of the system and the possibility of adaptation to the conventional tractor. Experiments were carried out to investigate the responses of the system to the step and sinusoidal inputs in draft control. The effects of control mode, hydraulic flow rate, reference deadband, and proportional constant on control performance of the system were investigated. Moreover, the effects of filtering signals from draft sensor were also investigated. The following conclusions were derived from the study; 1. In draft control, there were hunting problems in controlling the implement without filtering the draft signals. Filtering was performed by a control program of electronic controller and the control performance and stability of the system were improved significantly. 2. For the draft control system operated on on-off control mode, draft was controlled within ${\pm}27-{\pm}55kg_f$ to the reference draft when the hydraulic flow rates were 5-15 l/min. For the draft control system operated on PWM control, draft was controlled within ${\pm}27kg_f$ to the reference draft regardless of hydraulic flow rates. 3. In the frequency responses of the draft control system, control performance on PWM control mode was not better than on on-off control mode because of characteristics of hydraulic valve and drafe sensor. As the hydraulic flow rates increased for the system operated on on-off control mode, the corner frequency of amplitude attenuation increased, but the corner frequency of phase-angle change remained nearly the same. But, the system was unstable beyond the frequency of 3.1 rad/s. 4. The electronic-hydraulic hitch control system developed in this study showed superior control performance, stability and convenience compared to conventional mechanical-hydraulic hitch control system. It is considered to be a superior replacement for the conventional mechanical-hydraulic hitch control system.

• Agricultural and Biosystems Engineering
• /
• v.5 no.1
• /
• pp.10-20
• /
• 2004

Precision agriculture aims to minimize costs and environmental damage caused by agriculture and to maximize crop yield and profitability, based on information collected at within-field locations. In this process, quantification of soil physical properties, including soil strength, would be useful. To quantify and manage variability in soil strength, there is need for a strength sensor that can take measurements continuously while traveling across the field. In this paper, preliminary analyses were conducted using two datasets available with current technology, (1) cone penetrometer readings collected at different compaction levels and for different soil textures and (2) tillage draft (TD) collected from an entire field. The objective was to provide information useful for design of an on-the-go soil strength profile sensor and for interpretation of sensor test results. Analysis of cone index (CI) profiles led to the selection of a 0.5-m design sensing depth, 10-MPa maximum expected soil strength, and 0.1-MPa sensing resolution. Compaction level, depth, texture, and water content of the soil all affected CI. The effects of these interacting factors on data obtained with the soil strength sensor should be investigated through experiments. Spatial analyses of CI and TD indicated that the on-the-go soil strength sensor should acquire high spatial-resolution, high-frequency ($\ge$ 4 Hz) measurements to capture within-field spatial variability.

• Journal of Sensor Science and Technology
• /
• v.31 no.1
• /
• pp.64-68
• /
• 2022

Herein, we propose a LoRaWAN-based small draft system that can measure the ocean current flow (speed, direction, and distance) in real time at the request of the Coast Guard to develop a device that can promptly find survivors at sea. This system has been implemented and verified in the early stages of rescue after maritime vessel accidents, which are frequent. GPS signals often transmit considerable errors, so correction algorithms using the improved triangulation method algorithm are required to accurately indicate the direction of currents in real time. This paper is structured in the following manner. The introduction section elucidates rescue activities in the case of a maritime accident. Chapter 2 explains the characteristics and main parameters of the GPS surveying technique and LoRaWAN communication, which are related studies. It explains and expands on the critical distance error correction algorithm for GPS signals and its improvement. Chapter 3 discusses the design and analysis of small draft buoys. Chapter 4 presents the testing and validation of the implemented system in both onshore and offshore environments. Finally, Section 5 concludes the study with the expected impact and effects in the future.

• Journal of information and communication convergence engineering
• /
• v.9 no.5
• /
• pp.602-606
• /
• 2011

It is necessary for developing specific application protocol for mobile sensor end nodes and data collection devices that have constrained resources and computing powers. Because of these needs, IETF WG developed CoAP protocol and Internet draft was released, and processing to international standardization of this protocol. Because sensor nodes and information collection devices have restricted resources and computing powers, there are some limitations for applying to this proposed protocol directly. Thus in this paper we shows the implementation of full CoAP protocol for server, works on Linux and CoAP-Lite over telos which works on TinyOS for information collection devices. In this implementation we verified the main activities of CoAP protocol over USN by modifying some hardware with dependent algorithm.

• Convergence Security Journal
• /
• v.12 no.3
• /
• pp.27-34
• /
• 2012

In this paper, using a new low-power consumption method for ZigBee device, which consume low-power using an output power control algorithm through RSSI monitoring as interlocking wireless network using ZigBee which has advantages of a low-power consumption, a low-cost, a compatibility and a draft international standardization enacted by IEEE and ZigBee Alliance, with wired network using built coaxial cable to overcome the disadvantage of the existing wireless sensor network, is proposed. Effectiveness of the output power control algorithm through RSSI monitoring has been verified by experimentation for more optimized low-power consumption.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.52 no.10
• /
• pp.475-483
• /
• 2003

In this paper, dynamic characteristics of the magnetic flux leakage(MFL) type non-destructive testing(NDT) are analyzed. Effects of a sensor speed in MFL PIG system and remanent magnetization of the gas pipeline are analyzed by using 3 dimensional nonlinear finite element analysis including eddy current and hysteresis characteristics. Results show that the speed of the sensor reduces the magnitude of the sensing signals where as the hysteresis of the pipeline distorts the sensing signals.

• Special Issue of the Society of Naval Architects of Korea
• /
• 2006.09a
• /
• pp.112-121
• /
• 2006

The vertical displacement of a ship on the basis of the sea level is an important parameter for its stability and control. To indicate the displacement on operating conditions, "draft marks" are carved on the hull of the ship in various ways. One of the methods is welding. The position, shape and size of the marks are specified on the shipbuilding rules by classification societies to be checked by shipbuilders. In most cases, high-skilled workers do the welding along the drawing for the marks and welding bead becomes the marks. But the inaccuracies due to human errors and high labor cost increase the needs for automating the work process of the draft marks. In the preceding work, an indoor robot was developed for automatic marking system on flat surfaces and the work proved that the robot welding was more effective and accurate than manual welding. However, many parts of the hull structure constructed at the outdoor are cowed shapes, which is beyond the capability of the robot developed for the indoor works on the flat surface. The marking on the curved steel surface requiring the 25m elevations is one of the main challenges to the conventional robots. In the present paper, the robot capable of climbing vertical curved steel surfaces and performing the welding at the marked position by effectively solving the problems mentioned earlier is presented.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2010.10a
• /
• pp.507-509
• /
• 2010

To manage a sensing information such as temperature, humidity efficiently, it's highly recommended suitable application protocol. In this reasons, IETF WG proposed a CoAP protocol, and it's on Internet draft. If it is possible to work on a specific protocol, sensor end nodes and network devices will be managed efficiently. However, end nodes have constrained resources, it is hard to apply a CoAP protocol. In this paper, we analyse a CoAP protocol for USN, and propose a applying method for CoAP over USN nodes.

• Journal of Sensor Science and Technology
• /
• v.25 no.6
• /
• pp.388-393
• /
• 2016

MPEG-V(ISO/IEC 23005) standardizes normative sensory effects metadata and sensory devices command for adapting the sensory effects between the virtual world and the real world. MPEG-V(Virtual) standardization has been carried out by 3DG(Dimensional Graphics) ad-hoc group inside MPEG Working Group(ISO IEC JTC1/SC29/WG11). For the scent effect, one of the sensory effects within MPEG-V, we proposed an olfactory interaction model including electronic nose and scent display to the ad-hoc group. Recently, we proposed types and elements related to the electronic nose as a sensor defined in MPEG-V standard for olfactory interaction. At the 114th MPEG meeting, the types and elements were consequently reflected on MPEG-V CD(Committee Draft) 4th edition. In this paper, we implement an electronic nose system applicable to MPEG-V standard by using MPEG-V schema, encoder, and decoder in order to assess their adequacy.