• Journal of the Korean Institute of Intelligent Systems
• /
• v.26 no.2
• /
• pp.135-140
• /
• 2016

Corrective controllers enable fault diagnosis and tolerance for various faults in asynchronous sequential circuits without resort to redesign. In this paper, we propose a static corrective controller in order to decrease the size of the controller. Compared with dynamic controllers, static controllers can be made using only combinational circuits, as they need no inner states. We address the existence condition and design procedures for static corrective controllers that overcome state transition faults. To show the validity and advantage, the proposed controller is applied to an SEU error counter implemented on FPGA.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.22 no.1
• /
• pp.20-28
• /
• 2014

This paper presents static output feedback LQ and $H_{\infty}$ controllers for rollover prevention. Linear quadratic static output feedback controllers have been proposed for rollover prevention in such a way to minimize the lateral acceleration and the roll angle. Rollover prevention capability can be enhanced if $H_{\infty}$ controller is designed. To avoid full-state measurement for feedback requirement or sensitiveness of an observer to nonlinear model error, static output feedback is adopted. To design static output feedback controllers, Kosut's method is adopted because it is simple to calculate. Differential braking and active anti-roll bar are adopted as actuators that generate yaw and roll moments, respectively. The proposed method is shown to be effective in preventing rollover through the simulations on nonlinear multi-body dynamic simulation software, CarSim.

• International Journal of Control, Automation, and Systems
• /
• v.6 no.4
• /
• pp.495-505
• /
• 2008

This paper describes modeling Voltage Sourced Inverter (VSI) type Flexible AC Transmission System (FACTS) controllers and control methods for power system dynamic stability studies. The considered FACTS controllers are the Static Compensator (STATCOM), the Static Synchronous Series Compensator (SSSC), and the Unified Power Flow Controller (UPFC). In this paper, these FACTS controllers are derived in the current injection model, and it is applied to the linear and nonlinear analysis algorithm for power system dynamics studies. The parameters of the FACTS controllers are set to damp the inter-area oscillations, and the supplementary damping controllers and its control schemes are proposed to increase damping abilities of the FACTS controllers. For these works, the linear analysis for each FACTS controller with or without damping controller is executed, and the dynamic characteristics of each FACTS controller are analyzed. The results are verified by the nonlinear analysis using the time-domain simulation.

• International Journal of Control, Automation, and Systems
• /
• v.5 no.3
• /
• pp.349-354
• /
• 2007

This paper considers the problem of designing static output feedback controllers for nonlinear systems represented by Takagi-Sugeno (T-S) fuzzy models. Based on linear matrix inequality technique, a new method is developed for designing fuzzy stabilizing controllers via static output feedback. Furthermore, the result is also extended to $H_{\infty}$ control. Examples are given to illustrate the effectiveness of the proposed methods.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1992.10a
• /
• pp.192-197
• /
• 1992

The position error in multi-axis machine tools are due to many elements, such as the static friction, servo lag, a nonlinear disturbance, the gain mismatch between multi-axis controllers. In the work, modeling for the plant was carried out through the velocity response by the step input signal. Digital PI controllers, LQ optimal controllers and feedforward controllers are designed for a high tracking performance based on the model. The results of experimentation showed that the controllers worked properly.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1996.04a
• /
• pp.398-402
• /
• 1996

This paper addresses the design and the gait control of quadruped walking robot. First, we concern the mechanical and electronical(control system) hardware of walking robot, and the second is the results of experiments. The walking robot is the most suitable form to substitute fot human being. So walking robot is worthy of research. The quadruped walking robot and control system is the simplest type of walking robot, therefore we designed a small seale robot for realization of static gait. The robot is designed commpactly and its legs are constructed parallel link type and able to move freely in space. Control system consists of one upper level controller and four lower level controllers. The upper level controller plans the walking path and commands the low level controllers to follow the planned path. The main function of low level cotrollers is control of motors. Total number of motors is twealve and they operate four legs. And robot is ordered to walk and realize static wave gait.

• Journal of Energy Engineering
• /
• v.5 no.1
• /
• pp.72-79
• /
• 1996

The effect of controllers-Exciter, Power System Stabilizer, and Static Var Compensator-in one machine infinite bus system is investigated in this paper. The structure of generator state matrix with controllers is represented, while the Static Var Compensator is installed in generator terminal bus. Eigen-value analysis is performed and the effects of controllers to the dominant eigenvalue in one machine infinite bus system are represented by first order eigenvalue sensitivity coefficients while the operating conditions of the system are varied. Optimization of controller parameters using first order eigenvalue sensitivity coefficients is performed by the Simplex Method. It is proved that exciter control is the most efficient method to improve stability of the system and the effect of Static Var Compensator is small, in the case of one machine infinite bus system.

• Journal of Institute of Control, Robotics and Systems
• /
• v.11 no.9
• /
• pp.750-754
• /
• 2005

This paper deals with the design problem of multivariable PID controllers guaranteeing the closed-loop system stability and a prescribed $H_\infty$ norm bound constraint. We reduce the problem to the static output feedback stabilization problem. We derive a necessary and sufficient condition f3r the existence of PID controllers and we give an explicit formula of PID controllers. We also give an existence condition of PID controllers guaranteeing a prescribed decay rate. Finally, we give an LMI-based design algorithm, together with a numerical design example.

• Journal of Institute of Control, Robotics and Systems
• /
• v.20 no.7
• /
• pp.701-705
• /
• 2014

This article presents a comparison among several yaw and roll motion controllers for vehicle rollover prevention. In the previous research, yaw and roll motion controllers can be independently designed for rollover prevention. Following this idea, several yaw and roll motion controllers are designed and compared in terms of rollover prevention. For the yaw motion control, PID, LQR, SMC (Sliding Mode Control) and TDC (Time-Delay Control) are adopted. For the roll motion control, LQR, LQ SOF (Static Output Feedback) control, PID, and SMC are adopted. To compare the performance of each controller, simulation is performed on a vehicle simulation package, CarSim$^{(R)}$. From simulation, TDC and LQ SOF are the best for yaw and roll motion control, respectively.

• International Journal of Control, Automation, and Systems
• /
• v.6 no.1
• /
• pp.24-34
• /
• 2008

A novel neural network model, termed the standard neural network model (SNNM), similar to the nominal model in linear robust control theory, is suggested to facilitate the synthesis of controllers for delayed (or non-delayed) nonlinear systems composed of neural networks. The model is composed of a linear dynamic system and a bounded static delayed (or non-delayed) nonlinear operator. Based on the global asymptotic stability analysis of SNNMs, Static state-feedback controller and dynamic output feedback controller are designed for the SNNMs to stabilize the closed-loop systems, respectively. The control design equations are shown to be a set of linear matrix inequalities (LMIs) which can be easily solved by various convex optimization algorithms to determine the control signals. Most neural-network-based nonlinear systems with time delays or without time delays can be transformed into the SNNMs for controller synthesis in a unified way. Two application examples are given where the SNNMs are employed to synthesize the feedback stabilizing controllers for an SISO nonlinear system modeled by the neural network, and for a chaotic neural network, respectively. Through these examples, it is demonstrated that the SNNM not only makes controller synthesis of neural-network-based systems much easier, but also provides a new approach to the synthesis of the controllers for the other type of nonlinear systems.