• 제어로봇시스템학회:학술대회논문집
• /
• 1997.10a
• /
• pp.207-210
• /
• 1997

In this paper, a hierarchical fuzzy controller for stabilization of the inverted pendulum system is proposed. The facility of this hierarchical fuzzy controller which has a swing-up control mode and a stabilization one, moves a pendulum in an initial natural stable equilibrium point and a cart in arbitrary position to an unstable equilibrium point and a center of rail. Specially, the virtual equilibrium point (.PHI.$_{VEq}$ ) which describes functionally considers the interactive dynamics between a position of cart and a angle of inverted pendulum is introduced. And comparing with the convention optimal controller, the proposed hierarchical fuzzy inference made substantially the inverted pendulum system robust and stable.e.

• Journal of Institute of Control, Robotics and Systems
• /
• v.8 no.1
• /
• pp.67-73
• /
• 2002

This paper presents the development of development of stabilization and tracking algorithms for a shipboard satellite antenna system. In order to stabilize the satellite antenna system designed in the previous work, a model for each control axis is derived and its parameters are estimated using a genetic algorithm, and the state feedback controller is designed based on the linearized model. Then a tracking algorithm is derived to overcome some drawbacks of the step tracking. The proposed algorithm searches for the best position using gradient-based formulae and signal intensities measured according to a search pattern. The effectiveness of both the stabilization and tracking algorithms is demonstrated through experiment using real-world data.

• 전기의세계
• /
• v.31 no.1
• /
• pp.59-67
• /
• 1982

This paper suggests easy stabilization methods for linear time-varying systems with delay in the state. While existing methods employ the function space concept, the methods introduced in this paper transform the delay systems into the non-delay systems so that the well known methods for finite dimensional systems can be utilized. Particularly the intervalwise predictor is introduced and shown to satisfy an ordinary system. Control laws stabilizing the non-delay systems satisfied by this predictor will be shown to at least pointwise stabilize the delay systems with the additional strong possibility of true stabilization. In order to combine two steps of the predictor method, first transformation and then stabilization, an intervalwise regulator problem is suggested whose optimal control laws incorporate the intervalwise predictor as an integral part and also at least pointwise stabilize the delay systems. Since the above mentioned methods render the periodic feedback gains for time invariant systems the pointwise predictor and regulator are introduced in order to obtain the constant feedback gains, with additional stability properties. The control laws given in this paper are perhaps simplest and easiest to implement.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.66 no.1
• /
• pp.127-136
• /
• 2017

This paper investigates improved stability and stabilization criteria for sampled-data control systems. By using a suitable and newly constructed augmented Lyapunov-Krasovskii functional and some recent mathematic techniques such as auxiliary function-based integral inequalities, sufficient conditions for stability and stabilization conditions are derived within the framework of linear matrix inequalities(LMI) form. The superiority and validity of the proposed results are illustrated by three numerical examples.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.21 no.4
• /
• pp.508-519
• /
• 2018

This paper concerns on stabilization control of a gyro-stabilized 2-axes gimbal system which is mounted on a moving vehicles such as automobiles, armored vehicles, ships, flying vehicles, etc. A target image acquisition system is attached on the inner gimbal, and the gimbal systems are required to retain high stabilization accuracy in the absolute coordinate in order to provide fine target image while vehicle is moving. The stabilization control performance is hardly depended upon disturbance rejection ability of control, and disturbance feedforward compensation is effective because feedforward compensation reduce the amount of disturbance before the disturbance disturbs the systems. This paper suggests an experimental method which can estimate system parameters and disturbance torques by using 3-axes accelerometer mounted on the inner gimbal. Furthermore, a simple disturbance identification method which can be applied to any slanted base conditions has been suggested to identify mass unbalance vector and friction torques of each gimbal simultaneously. By using the estimated parameters, a feedforward compensation has been applied to the gyro-stabilized 2-axes gimbal system. The experimental results showed that the feedforward compensation based on the identification method suggested is effective to improve stabilization performances.

• PNF and Movement
• /
• v.22 no.2
• /
• pp.201-211
• /
• 2024

Purpose: This study aimed to evaluate the effects of trunk stabilization exercises using a Reformer on trunk control, balance ability, and gait function in chronic stroke patients. Methods: The participants were 24 chronic stroke patients, randomly divided into two groups: trunk stabilization exercise using the Reformer group (TS-R, n = 12) and general trunk stabilization exercise group (GT-E, n = 12). Assessment methods included the Trunk Impairment Scale for trunk control, the AMTI force platform for static balance, the Timed Up and Go test for dynamic balance, and the Dynamic Gait Index for gait function. Assessments were conducted before and after the intervention. The intervention for the TS-R group consisted of bridging exercises using a Reformer, while the GT-E group performed bridging exercises on a mat. All interventions were performed for 17 minutes per session, five times a week, for a total of 20 sessions over four weeks. Statistical analysis was performed using repeated-measures ANOVA to analyze the interaction between groups and time. Results: The results of the repeated measures ANOVA indicated a significant interaction between the groups and time. The TS-R group showed statistically significant differences in all variables before and after the intervention. In contrast, the GT-E group did not show statistically significant differences in any variables before and after the intervention. Conclusion: The findings of this study suggest that trunk stabilization exercises using a reformer are effective in improving trunk control, balance ability, and gait function in chronic stroke patients.

• International Journal of Control, Automation, and Systems
• /
• v.4 no.6
• /
• pp.682-688
• /
• 2006

This paper deals with the delay-dependent and rate-independent stabilization of systems with multiple unknown time-varying delays and time-varying structured uncertainties. All the linear matrix inequalities based conditions are derived by employing free-weighting matrices to express the relationships between the terms in the Leibniz-Newton formula. The criteria do not require any tuning parameters. Numerical examples demonstrate the validity of the method.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.39 no.8
• /
• pp.792-804
• /
• 1990

This paper describes an efficient optimization algorithm by calculating sensitivity function for power system stabilization. In power system, the dynamic performance of exciter, governor etc. following a disturbance can be presented by a nonlinear differential equation. Since a nonlinear equation can be linearized for small disturbances, the state equation is expressed by a system matrix with system parameters. The objective function for power system operation will be related to the system parameter and the initial state at the optimal control condition for control or stabilization. The object function sensitivity to the system parameter can be considered to be effective in selecting the optimal parameter of the system.

• International Journal of Control, Automation, and Systems
• /
• v.1 no.4
• /
• pp.515-519
• /
• 2003

This paper proposes a new image sequence stabilization (ISS) scheme based on filtering of absolute frame positions. The proposed ISS scheme removes undesired motion effects in real-time, while preserving desired gross camera displacements. The well-known finite impulse response (FIR) filter is adopted for filtering. The proposed ISS scheme provides a filtered position and velocity with fine inherent properties. It is demonstrated that the filtered position is not affected by the constant velocity. It is also shown that the filtered velocity is separated from the position. Via numerical simulations, the performance of the proposed scheme is shown to be superior to the existing Kalman filtering scheme.

• Journal of the Optical Society of Korea
• /
• v.2 no.1
• /
• pp.34-37
• /
• 1998

We present a novel method for the stabilization of the Sagnac current sensor with active twist control. The sensor output was improved more than 8 times by employing the proposed stabilization method. Stability within $\pm$1.7% was demonstrated between 36$^{\circ}C$ and 62$^{\circ}C$.