• 제어로봇시스템학회:학술대회논문집
• /
• 1998.10a
• /
• pp.100-104
• /
• 1998

This paper describes the real-time implementation of an adaptive controller fur the robotic manipulator. Digital signal processors(DSPs) are special purpose micro-processors that are particularly powerful for intensive numerical computations involving sums and products of variables. TMS320C50 chips are used in implementing real time adaptive control algorithms to provide an enhanced motion for robotic manipulators. In the proposed scheme, adaptation laws are derived from the improved Lyapunov second stability analysis based on the direct adaptive control theory. The adaptive controller consists of an adaptive feedforward controller and feedback controller. The proposed control scheme is simple in structure, fast in computation, and suitable for real-time control. Moreover, this scheme does not require any accurate dynamic modeling, nor values of manipulator parameters and payload. Performance of the adaptive controller is illustrated by simulation and experimental results for a assembling robot.

• International journal of advanced smart convergence
• /
• v.12 no.2
• /
• pp.173-181
• /
• 2023

Data collection is an essential element in the construction and operation of a smart factory. The quality of data collection is greatly influenced by network conditions, and existing wireless network systems for IoT inevitably lose data due to wireless signal strength. This data loss has contributed to increased system instability due to misinformation based on incorrect data. In this study, I designed a distributed MQTT IoT smart sensor and gateway structure that supports wireless multicasting for smooth sensor data collection. Through this, it was possible to derive significant results in the service latency and data loss rate of packets even in a wireless environment, unlike the MQTT QoS-based system. Therefore, through this study, it will be possible to implement a data collection management system optimized for the domestic smart factory manufacturing environment that can prevent data loss and delay due to abnormal data generation and minimize the input of management personnel.

• Journal of the Korean Society for Precision Engineering
• /
• v.12 no.11
• /
• pp.125-131
• /
• 1995

Pneumatic System has been mainly used as main equipment for actuation and control of fluid force in manufacturing industry. For velocity control of piston, meter-out restriction method is used in many cases. In this systems, meter-out restriction method is adopted for analysing the Dynamic Charging and Discharging Process which is Variable Volume Chamber. Experiments has been conducted for different supply pressure condition. As a experimental result, charge side chamber pressure rises to supply pressure rapidily and discharge side chamber pressure decreases. Also, when the air in the cylinder is discharged, tempdrature of air decreases steeply. Restriction of the Cylinder sometimes freeze and it dose not function. The result will be useful for the analysis of pneumatic system.

• International conference on construction engineering and project management
• /
• 2011.02a
• /
• pp.304-310
• /
• 2011

The populations of major cities in Australia are increasing rapidly and facing an acute housing shortage. Traditional apartment procurement techniques involve lengthy lead-times and factory-based, or offsite manufactured (OSM) multi-storey apartment buildings may offer the opportunity to help fulfill the need by significantly reducing build times. Other advantages of OSM may include superior quality, low weight ratios, economies of scale achieved through repetition of prefabricated units, use on infill sites, sustainable design standards and better occupational health and safety. There are also positive labour and training implications, which may help to alleviate an industry-wide shortage of skills through use of semi-skilled labour. Previous uncertainties about the adoption of offsite due to the high capital costs and perception issues were generally based on pre-cast concrete structures, which are quite a different building type in terms of flexibility, construction, delivery and finishes. Identification of drivers and constraints assists in the determination of current industry status, allows for a benchmark to be established and future opportunities and directions for OSM to be determined.

• Journal of the Society of Naval Architects of Korea
• /
• v.45 no.2
• /
• pp.202-212
• /
• 2008

In recent days, global shipbuilding companies have been increasing their productivity or expanding their shipyards for a large amount of orders. Though, few researches about the shipyard layout designs have been studied. This research presents a simulation-based shipyard layout design framework to resolve the problems of the shipyard layout design. The shipyard layout design framework was developed on the basis of systems engineering method. The disciplined system engineering technique was guided by ISO/IEC 15288 during the planning phase of the shipyard layout design framework development. This framework suggests that how efficient and effective shipyard layout design could be got, that can satisfy the stakeholder of the layout. Furthermore, it is recommended that how the proposed shipyard layout should be verified and validated by digital simulation model. It is expected that the framework will contribute to not only the improvement of the existing shipyard but also the construction of the new shipyard.

• International Journal of Reliability and Applications
• /
• v.2 no.3
• /
• pp.209-240
• /
• 2001

Computer-based simulation and analysis is used extensively in engineering for a variety of tasks. Despite the steady and continuing growth of computing power and speed, the computational cost of complex high-fidelity engineering analyses and simulations limit their use in important areas like design optimization and reliability analysis. Statistical approximation techniques such as design of experiments and response surface methodology are becoming widely used in engineering to minimize the computational expense of running such computer analyses and circumvent many of these limitations. In this paper, we compare and contrast five experimental design types and four approximation model types in terms of their capability to generate accurate approximations for two engineering applications with typical engineering behaviors and a wide range of nonlinearity. The first example involves the analysis of a two-member frame that has three input variables and three responses of interest. The second example simulates the roll-over potential of a semi-tractor-trailer for different combinations of input variables and braking and steering levels. Detailed error analysis reveals that uniform designs provide good sampling for generating accurate approximations using different sample sizes while kriging models provide accurate approximations that are robust for use with a variety of experimental designs and sample sizes.

• Korean Journal of Computational Design and Engineering
• /
• v.21 no.1
• /
• pp.9-19
• /
• 2016

Applying human engineering simulation to analyzing work capability and movements of operators during manufacturing is highly demanded. However, difficulty in modeling digital human required for simulation makes engineers to be reluctant to utilize human simulation for their tasks. This paper addresses such problem on human engineering simulation by developing the technology to automatize human modeling with multiple Kinects at different depths. The Kinects enable us to acquire the movements of digital human which are essential data for implementing human engineering simulation. In this paper, we present a system for modeling automation of digital human. Especially, the system provides a way of generating the digital model of workers' movement and position using multiple Kinects which cannot be generated by single Kinect. Lastly, we verify the effects of the developed system in terms of modeling time and accuracy by applying the system to four different scenarios. In conclusion, the proposed system makes it possible to generate the digital human model easily and reduce costs and time for human engineering simulation.

• Steel and Composite Structures
• /
• v.38 no.5
• /
• pp.583-597
• /
• 2021

This article develops a nonclassical model to analyze bending response of squared perforated microbeams considering the coupled effect of microstructure and surface stress under different loading and boundary conditions, those are not be studied before. The corresponding material and geometrical characteristics of regularly squared perforated beams relative to fully filled beam are obtained analytically. The modified couple stress and the modified Gurtin-Murdoch surface elasticity models are adopted to incorporate the microstructure as well as the surface energy effects. The differential equations of equilibrium including the Poisson's effect are derived based on minimum potential energy. Exact closed form solution is obtained for bending behavior of the proposed model considering the classical and nonclassical boundary conditions for both uniformly distributed and concentrated loads. The proposed model is verified with results available in the literature. Influences of the microstructure length scale parameter, surface energy, beam thickness, boundary and loading conditions on the bending behavior of perforated microbeams are investigated. It is observed that microstructure and surface parameters are vital in investigation of the bending behavior of perforated microbeams. The obtained results are supportive for the design, analysis and manufacturing of perforated nanobeams that commonly used in nanoactuators, nanoswitches, MEMS and NEMS systems.

• Information Systems Review
• /
• v.7 no.2
• /
• pp.117-128
• /
• 2005

This study proposes an integrated monitoring system for data reliability improvement in a steel manufacturing industry. The data obtained from existing steel manufacturing process is not micro data which is gathered at the occurring point, but average value (macro data) which is gathered from the occurring point to ending point. This kind of macro data is not only difficult for a detailed analysis for an error causing factor, but it might cause a fatal influence as well on the quality of produced goods even if the error is within an error tolerance. And during the process of steel production, thousands of data is produced in a second, thus requiring database plan to manage abundant amount of data. Therefore, the following proposed system is capable of collecting as well as analyzing all the data generated from the process of product production. And the system was able to raise the efficiency of the database server by planning the database to handle large capacity data. Also, by applying web-based technology, inquiries and analysis of data with no limit on time and space was possible with PC connected to the intranet. Hence, the system was able to work on effective quality improvement of manufactured products, plus able to raise the reliability of the product. Also, accumulated data from long period of time was used for fundamental material for new controlling model, operation technology, and new product development.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.25 no.5
• /
• pp.338-344
• /
• 2016

Recent trends in transport system for carrying heavy freight are that demands of a high efficiency, economic efficiency, convenience and safety are increased. Conventional transport systems were poor in transport efficiency and economic efficiency. And Safety problems can be caused to products and workers. In order to overcome these problems, an air cushion transport device with a high-pressure air is required. The air cushion transporter is a device for reducing the frictional force of floor surface and lifting the heavy freight by spraying the high-pressure air to the floor. Technology to float and transfer freight using high-pressure air is very convenient and initial cost can be reduced. In this paper, the study on the levitation performance and transport efficiency of air cushion transport system is conducted and verified that air cushion transporter has a significantly higher transport efficiency than conventional heavy handling systems.