• Transactions on Control, Automation and Systems Engineering
• /
• v.2 no.2
• /
• pp.98-103
• /
• 2000

This paper is concerned with a delay-dependent sliding mode scheme for the robust stabilization of input-delay systems with bounded unknown uncertainties. A sliding surface based ona predictor is proposed to minimize the effect of the input delay. Then, a robust control law is derived to ensure the existence of a sliding mode on the surface. In input-delay systems, uncertainties given during te delayed time are not directly controlled by the switching control because of causality prolem of them. They can influence the stability of the system in the sliding mode. Hence, a delay-dependent stability analysis for reduced order dynamics is employed to estimate maximum delay bound such that the system is globally asymptotically stable in the sliding mode. A numerical example is given to illustrate the design procedure.

• Journal of Advanced Marine Engineering and Technology
• /
• v.25 no.2
• /
• pp.321-330
• /
• 2001

Magnetic bearing system is frequently used for high-speed rotating machines because of its frictionless property. But the magnetic bearing system needs feedback controller for stabilization. This paper presents a robust controller design by using linear matrix inequality for magnetic bearing system which shows the control performance and robust stability under the physical parameter perturbations. To the end, the validity of the designed controller is investigated through computer simulation.

• Transactions on Control, Automation and Systems Engineering
• /
• v.3 no.3
• /
• pp.164-169
• /
• 2001

This paper considers the problem of robust stabilization and disturbance attenuation for a class of uncertain singularly perturbed systems with norm-bounded nonlinear uncertainties. It is shown that the state feedback gain matrices can be determined to guarantee the stability of the closed-loop system for all $\varepsilon$$\in$(0, $\infty$). Based on this key result and some standard Riccati inequality approaches for robust control of singularly perturbed systems, a constructive design procedure is developed.

• Journal of the Institute of Convergence Signal Processing
• /
• v.2 no.3
• /
• pp.57-64
• /
• 2001

This paper propose a robust control method to achieve a desired system performance in spite of system uncertainty and disturbance uncertainty. The procedures of the robust controller based on QFT(Quantitative Feedback Theory) make template, bound and loop shaping which are considered by system parameter variations and performance specifications. To prove the efficiency, the designed controller is applied for an inverted pendulum which is so sensitive to the parameter variation and has a highly nonlinear and unstable characteristics. It is shown that the simulation and experimental results from the proposed controller are efficient in robustness of parameter variation and disturbance.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.19 no.4
• /
• pp.464-469
• /
• 2009

This paper discusses a robust observer-based output-feedback stabilization of an uncertain Takagi-Sugeno (T-S) fuzzy system in a network. In the networked control system, the input delay occurs inevitably and it is expressed by the Markovian stochastic process. To design robust sampled-data observer-based output-feedback controller, we discretize the T-S fuzzy system and represent as a jump system. Stochastic robust stabilization condition is formulated in terms of linear matrix inequalities.

• 제어로봇시스템학회:학술대회논문집
• /
• 1996.10b
• /
• pp.1197-1200
• /
• 1996

This paper is concerned with the design of robust state feedback controller for a class of linear time-delay systems with norm-bounded nonlinear uncertainties. Under the proposed delay-independent criterion, asymptotic stability for the system is investigated using the conventional Lyapunov method. Moreover, the robust controller can be obtained by solving the linear matrix inequality which is equivalent to the suggested conditions.

• 제어로봇시스템학회:학술대회논문집
• /
• 1992.10a
• /
• pp.742-746
• /
• 1992

This paper proposes a new linear robust state feedback controller for the linear discrete time systems which have uncertainties in the state and input matrices. The uncertainties need not satisfy the matching conditions, but only their bounds are needed to be known. The proposed controller is derived from the linear quadratic game problem, which solution is obtained via the modified algebraic Riccati equation. The controller guarantees the robust performance bound. The bound of the solution and the condition of the uncertainties, which can stabilize the uncertain system are explored.

• Proceedings of the KIEE Conference
• /
• 2000.07d
• /
• pp.2293-2295
• /
• 2000

This paper describes the synthesis of robust decentralized controllers for uncertain large-scale discrete-time systems with time-delays in subsystem interconnections. Based on the Lyapunov method, a sufficient condition for robust stability, is derived in terms of a linear matrix inequality(LMI). The solutions of the LMI can be easily obtained using various efficient convex optimization techniques. A numerical example is given to illustrate the proposed method.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.26 no.2
• /
• pp.127-134
• /
• 2016

This paper presents a robust control of a reaction wheel inverted pendulum. To this end, a mathematical model is derived using physical laws, and then parameters in the model are identified as well. Based on the model, a robust position control is designed, which consists of two parts: swing-up control using passivity and robust stabilization control using LMI (Linear Matrix Inequality). When the pendulum starts to move, the swing-up control is applied. If the position of the pendulum is near the desired upright position, the control is switched to the robust stabilization control. This robust control is employed in order to deal with the uncertainties in the inertia of the pendulum dynamics. The performance of the proposed control scheme is validated not only simulation but also real experiment.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.58 no.1
• /
• pp.160-167
• /
• 2009

In this paper, we apply the robust disturbance observer (DOB) to a SPM-based data storage (SDS) system. In the SDS system, coupling dynamics and parameter uncertainties are obstacles to the precision tracking control. Although the DOB is known to be an effective method to reject disturbances, there has been no systematic design approach to how to design DOB parameters. In this paper, the robust DOB is formulated based on the robust stabilization of normalized coprime factor plant description and the $H{\infty}$ loop shaping method. From the simulation and experimental results. the improved robustness and performance are obtained by the proposed robust DOB.