• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 2003.09a
• /
• pp.443-446
• /
• 2003

Conventional disturbance rejection methods have to derive the inverse model of a system. However, the inverse model of n nonholonomic system is not unique, because an inverse it changes depending on initial conditions and desired values. A kind of internal model control (IMC) using feedback error learning is discussed for the motion control of nonholonomic mobile robots in this paper, The present method is different from a conventional IMC whose control system consists of an inverse model, a direct model and a filter. The present disturbance rejection method need not use a direct model, where the remaining two elements are composed of the same inverse model based on neural networks.

• Journal of the Korean Society for Industrial and Applied Mathematics
• /
• v.8 no.1
• /
• pp.11-30
• /
• 2004

Access Control is one of essential branches to provide system's security. Depending on what standards we apply, in general, there are Role-based access control, History-based access control. The first is based on subject's role, The later is based on subject's history. In fact, RBAC has been implemented, we are using it by purchasing some orders through the internet. But, HBAC is so complex that there will occur some errors on the system. This is more and more when HBAC is used with other access controls. So HBAC's formalization and model which are general enough to encompass a range of policies in using more than one access control model within a given system are important. To simplify these, we design the mathematical model called non-access structure. This Non-access structure contains to historical access list. If it is given subjects and objects, we look into subject grouping and object relation, and then we design Non-access structure. Then we can determine the permission based on history without conflict.

• 제어로봇시스템학회:학술대회논문집
• /
• 1998.10a
• /
• pp.468-473
• /
• 1998

A mathematical model was developed for a continuous re-actor in which free radical polymerization of methyl methacrylate (MMA) occurred. Elementary reactions considered in this study were initiation, propagation, termination, and chain transfers to monomer and solvent. The reactor model took into account the density change of the reactor contents and the gel effect. A control system was designed for a continuous reactor using extended Kalman filter (EKF) based non-linear model predictive controller (NLMPC) to control the conversion and the weight average molecular weight of the polymer product. Control input variables were the jacket inlet temperature and the feed flow rate. For the purpose of validation of the control strategy, on-line digital control experiments were conducted with densitometer and viscometer for the measurement of the polymer properties. Despite the com-plex and nonlinear features of the polymerization reaction system, the EKF based NLMPC performed quite satisfactorily for the property control of the continuous polymerization reactor.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.20 no.1
• /
• pp.95-105
• /
• 2012

The selective catalytic reduction (SCR) system is a highly-effective aftertreatment device for NOx reduction of diesel engines. Generally, the ammonia ($NH_3$) was generated from reaction mechanism of SCR in the SCR system using the liquid urea as the reluctant. Therefore, the precise urea dosing control is a very important key for NOx and $NH_3$ slip reduction in the SCR system. This paper investigated NOx and $NH_3$ emission characteristics of urea-SCR dosing system based on model-based control algorithm in order to reduce NOx. In the map-based control algorithm, target amount of urea solution was determined by mass flow rate of exhaust gas obtained from engine rpm, torque and $O_2$ for feed-back control NOx concentration should be measured by NOx sensor. Moreover, this algorithm can not estimate $NH_3$ absorbed on the catalyst. Hence, the urea injection can be too rich or too lean. In this study, the model-based control algorithm was developed and evaluated on the numerical model describing physical and chemical phenomena in SCR system. One channel thermo-fluid model coupled with finely tuned chemical reaction model was applied to this control algorithm. The vehicle test was carried out by using map-based and model-based control algorithms in the NEDC mode in order to evaluate the performance of the model based control algorithm.

• 제어로봇시스템학회:학술대회논문집
• /
• 1996.10b
• /
• pp.156-159
• /
• 1996

An adaptive predictive control for steam-reforming plant which consist of a steam-gas reformer and a waste heat steam-boiler was studied by using MIMO bilinear model. The simulation experiments of the process identification were performed by using linear and bilinear models. From the simulation results it was found that the bilinear model represented the dynamic behavior of a steam-reforming plant very well. ARMA model was used in the process identification and the adaptive predictive control. To verify the performance and effectiveness of the adaptive predictive controller proposed in this study the simulation results of steam-reforming plant control based on bilinear model were compared to those of linear model. The simulation results showed that the adaptive predictive controller based on bilinear model provides better performance than those of linear model.

• Convergence Security Journal
• /
• v.1 no.1
• /
• pp.1-7
• /
• 2001

This paper design a role-based access control model that can resolves the complicated problems of access control requirements. In this paper, we designed an access control model which can control a permission making use up role-based access control, can guard the confidentiality, integrity and availability of information and can control illegal information flow. The designed access control model can protect resources from unauthorized accesses based on the role, multi-level security policies of security level, integrity level and ownership.

• Journal of Power System Engineering
• /
• v.18 no.4
• /
• pp.91-96
• /
• 2014

The application of the recent model-based control schemes for robot manipulators require the solution of problems concerning various aspects, from the mechanical design to the necessity of determining a robot model suitable for control, and of experimentally testing the control performances. For one solution, integration of SolidWorks with Simscape for designing and controlling robot manipulators is presented in this paper. The integration provides a platform for rapid control prototyping of robot manipulators without the need for building real prototypes. Mechanical drawings of a robot are first created using Solidworks and imported into the Simscape, where a robot is represented by connected block diagrams based on the principle of physical modeling. Simulation examples for 7-DOF SAM ARM made by Berrett Technology Inc. are testified to show effectiveness of the presented platform.

• Smart Structures and Systems
• /
• v.14 no.6
• /
• pp.1081-1103
• /
• 2014

Real-time hybrid simulation (RTHS) has emerged as an important tool for testing large and complex structures with a focus on rate-dependent specimen behavior. Due to the real-time constraints, accurate dynamic control of servo-hydraulic actuators is required. These actuators are necessary to realize the desired displacements of the specimen, however they introduce unwanted dynamics into the RTHS loop. Model-based actuator control strategies are based on linearized models of the servo-hydraulic system, where the controller is taken as the model inverse to effectively cancel out the servo-hydraulic dynamics (i.e., model-based feedforward control). An accurate model of a servo-hydraulic system generally contains more poles than zeros, leading to an improper inverse (i.e., more zeros than poles). Rather than introduce additional poles to create a proper inverse controller, the higher order derivatives necessary for implementing the improper inverse can be calculated from available information. The backward-difference method is proposed as an alternative to discretize an improper continuous time model for use as a feedforward controller in RTHS. This method is flexible in that derivatives of any order can be explicitly calculated such that controllers can be developed for models of any order. Using model-based feedforward control with the backward-difference method, accurate actuator control and stable RTHS are demonstrated using a nine-story steel building model implemented with an MR damper.

• Journal of Institute of Control, Robotics and Systems
• /
• v.12 no.3
• /
• pp.227-232
• /
• 2006

In this paper, we propose a systematic method for intelligent digital redesign of a fuzzy-model-based controller for continuous-time nonlinear system which may also contain system uncertainties. The continuous-time uncertain TS fuzzy model is first contructed to represent the uncertain nonlinear system. A parallel distributed compensation(PDC) technique is then used to design a fuzzy-model-based controller for both stabilization. The designed continuous-time controller is then converted to an equivalent discrete-time controller by using a globally intelligent digital redesign method. This new technique is designed by a global matching of state variables between analog control system and digital control system. This new design technique provides a systematic and effective framework for integration of the fuzzy-model-based control theory and the advanced digital redesign technique for nonlinear systems with uncertainties. Finally, Chaotic Lorenz system is used as an illustrative example to show the effectiveness and the feasibility of the developed design method.

• Journal of Drive and Control
• /
• v.12 no.4
• /
• pp.41-47
• /
• 2015

Hydraulic manipulators have been widely used in many different fields due to their high force/torque to inertia ratio. The increased speed of hydraulic manipulators requires solutions to problems ranging from mechanical design to the need to determine a robot model suitable for model-based control. As a solution, this paper presents the integration of SolidWorks with Simscape for designing and controlling hydraulic manipulators. The integration provides a platform for the rapid control prototyping of a hydraulic robot without the need to build actual prototypes. The mechanical drawings of a manipulator are first created using Solidworks and are then imported into Simscape, where the manipulator is represented by connected block diagrams based on the principle of physical modeling. Simulation examples for a 3D manipulator made by KNR SYSTEM INC are verified to show the effectiveness of the presented platform.