• International Journal of Control, Automation, and Systems
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• v.6 no.3
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• pp.394-400
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• 2008

A known nonlinear compensator design approach is adapted to allow design of nonlinear lead and/or lag compensators, and a number of MATLAB functions are developed that automate the compensator design procedure. With this design tool, control engineers would be able to rapidly design nonlinear lead and/or lag compensators. An example of a tutorial nature is presented.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.7
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• pp.575-582
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• 2004

The observer design problem is studied for a class of multi-output nonlinear systems that are not necessarily observable. Generalized nonlinear observer canonical form is introduced for multi-output nonlinear systems to design nonlinear observers. Sufficient conditions are given for a nonlinear system to be transformed by state-space change of coordinates into generalized nonlinear observer canonical form. Based on this canonical from, a sufficient condition is also given for the existence of nonlinear observers. An illustrative example is presented to show the design procedure of the proposed method.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.241-244
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• 1996

This paper discusses the general properties and the design procedures of Internal Model Control(IMC) scheme for nonlinear plants. Also we propose new nonlinear IMC(NIMC) design method using linear IMC. Although all IMC controllers can be thought simple 'inverse controller', its nonlinear realization is not easy. Propose NIMC is composed multiple linear models, IMC controllers, and switching scheme. The advantages of this method are we can use simple linear IMC design method and need not nonlinear modelings.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.633-635
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• 1997

In this paper we present a scheme of adaptive backstepping controller for nonlinear system. Backstepping approach has recently been adopted as a design tool for nonlinear control and especially backstepping with modular design used to seperately design controller and identifier. In the modular design the nonlinear damping term is contained in controller for input-to-state stability (ISS). We compare the ISS controller, which used in general case, with the weak-ISS controller that attenuates the effect of nonlinear damping term and prove their advantages and disadvantages by simulation.

• Proceedings of the IEEK Conference
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• 2001.06c
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• pp.17-20
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• 2001

In this paper, we design a nonlinear adaptive controller using wavelet neural network. The method proposed in this paper performs for a nonlinear system with unknown parameters, identification with using a wavelet neural network, and then a nonlinear adaptive controller is designed with those identified informations. The advantage of the proposed control method is simple to design a controller for unknown nonlinear systems, because we use the identified informations and design parameters are positioned within a negative real part of s-plane. The simulation results showed the effectiveness of proposed controller design method.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.04a
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• pp.392-397
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• 1997

In this paper, design and analysis of anchorage zone in prestressed concrete structure using nonlinear strut and tie model is presented. Nonlinear strut and tie model is an analysis and design model which constructs strut and tie model based on nonlinear analysis considering the nonlinear behavior of concrete. Based on the nonlinear strut and tie model, the analysis and design are performed for the anchorage zone having singular concentric tendons, singular eccentric tendons and multiple tendons, respectively. For verification of the model, comparisons are made with experimental results as well as results by linear strut and tie models. from the comparisons, it is shown that the design of the anchorage zone by the nonlinear model is still economical without loosing the degree of safety and the prediction of the ultimate load by the nonlinear model gives better accuracy than by the linear one.

• Earthquakes and Structures
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• v.15 no.2
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• pp.155-164
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• 2018

Design of structures subjected to blast loads are usually carried out through nonlinear inelastic dynamic analysis followed by imposing acceptance criteria specified in design codes. In addition to comprehensive aspects of inelastic dynamic analyses, particularly in analysis and design of structures subjected to transient loads, they inherently suffer from convergence and computational cost problems. In this research, a strategy is proposed for design of steel moment resisting frames under far range blast loads. This strategy is inspired from performance based seismic design concepts, which is here developed to blast design. For this purpose, an algorithm is presented to calculate the capacity modification factors of frame members in order to simplify design of these structures subjected to blast loading. The present method provides a simplified design procedure in which the linear dynamic analysis is preformed, instead of the time-consuming nonlinear dynamic analysis. Nonlinear and linear analyses are accomplished in order to establish this design procedure, and consequently the final design procedure is proposed as a strategy requiring only linear structural analysis, while acceptance criteria of nonlinear analysis is implicitly satisfied.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.7
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• pp.1295-1301
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• 2010

In this note, a systematic general design of a new robust nonlinear variable structure controller based on state dependent nonlinear form is presented for the control of uncertain affine nonlinear systems with mismatched uncertainties and mismatched disturbance. After an affine uncertain nonlinear system is represented in the form of state dependent nonlinear system, a systematic design of a new robust nonlinear variable structure controller is presented. To be linear in the closed loop resultant dynamics, the nonlinear integral-type sliding surface is applied. A corresponding control input is proposed to satisfy the closed loop exponential stability and the existence condition of the sliding mode on the nonlinear integral-type sliding surface, which will be investigated in Theorem 1. Through a design example and simulation studies, the usefulness of the proposed controller is verified.

• Structural Engineering and Mechanics
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• v.34 no.5
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• pp.581-595
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• 2010

This paper presents topology optimization of geometrically and materially nonlinear structures using a bi-directional evolutionary optimization (BESO) method. To maximum the stiffness of nonlinear structures under prescribed design load, the complementary work is selected as the objective function of the optimization. An optimal design can be obtained by gradually removing inefficient material and adding efficient ones. The proposed method can be applied to a series of geometrically and/or materially nonlinear structures. The results show considerable differences in topologies and stiffness of the optimal designs for linear and nonlinear structures. It is found that the optimal designs for nonlinear structures are much stiffer than those for linear structures when large design loads (which result in significantly nonlinear deformations) are applied.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.675-677
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• 2004

This paper presents a nonlinear controller design for optical disk drive systems to improve anti-shock performance. The nonlinear anti-shock controller is added parallel to the original linear servo control loop. In the previous work, dead-zone nonlinear element is used for nonlinear controller and PID control method is used for linear controller. Although this strategy improves anti-shock performance, it has a narrow stability bound. In this paper, we propose dead-zone with saturation nonlinear element for the nonlinear controller. Since this nonlinear element improves stability margin, we can use higher gain of dead-zone than the controller with dead-zone only. In the linear controller design, we show that lead-lag control has improved stability margin over PID control. Numerical simulation results show that the proposed method can get better performance to the external shock than previously proposed method.