• Journal of Power Electronics
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• v.18 no.4
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• pp.1099-1110
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• 2018

In this paper, a loss minimization control method for interior permanent magnet synchronous motors is presented with considering self-saturation and cross saturation. According to variation of the d-axis and q-axis inductances by different values of the d-axis and q-axis components of currents, it is necessary to consider self-saturation and cross saturation in the loss minimization control method. In addition, the iron loss resistance variation due to frequency variation is considered in the condition of loss minimization. Furthermore, the loss minimization control method is compared with maximum torque per ampere (MTPA), unity power factor (UPF) and $i_d=0$ control methods. Experimental results verify the performance and proper dynamic response of the loss minimization control method with considering self-saturation and cross saturation.

• Journal of Ocean Engineering and Technology
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• v.16 no.4
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• pp.61-69
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• 2002

In the actual control systems, there exist many kinds of restrictions or nonlinearities. However, due to the nonlinearities in actuators and sensors, the designed controller may not be applicable in some practical situations. One such nonlinearity is amplitude saturation in actuators. Although sometimes it may be ignored, in other cases failure to consider actuator saturation may severely degrade closed-loop system performance and even lead to instability. On the other hand, limiting the controller gain to avoid saturation sacrifices control effort and may lead to loss of performance. Consequently, in some cases, the actuator saturation must be explicitly taken into account to ensure desired performance. However, in this paper, an anti-windup control system design method is introduced to suppress the windup due to the amplitude saturation of the actuator. The proposed control system has very simple design process and guarantees the good control performance. The validity of the proposed control system will be shown by comparing with the results of a reported paper.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.9
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• pp.768-776
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• 2000

A robust high-speed motion controller is proposed. The proposed controller consists of the proximate time optimal servomechai는 (PTOD) for high-speed motion, disturbance observer (DOB) for robustness, friction compensator, and saturation handling element, In the proposed controller, DOB basically provides the chance to apply PTOS to non-double integrator systems by drastically reducing disturbances as well as unwanted signals due to difference between real system and the double integrator model. But, in DOB-based systems, if control input is saturated due to control input PTOS and/or DOB, overall system stability cannot be guaranteed. To solve this problem, ribust stability, when the control input is saturated. Eventually, a simple saturation handling element is inserted to maintain internal stability of overall system. Also, we explain the our two saturation handling methods, Additional Saturation Element (ASE_ and Self Adjusting Saturation (SAS), are the equivalent solutions of the saturation problem to maintain internal stability. The stability and performance of the proposed controller are verified through numerical simulations and experiments using a precision linear motor system.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.10
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• pp.894-902
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• 2000

This paper proposes a force reflection control method with a speed saturation compensation scheme for the slave manipulators having a speed saturation due to the high reduction ratio joints. When speed saturation is generated, the proposed force reflection control method not only shows an anti-windup feature in controlling the slave manipulator but also makes the master manipulator move slowly using the force reflection caused by saturation. In this way, the position of the slave manipulator tracks the reference position regardless of speed saturation. The experimental results show that the proposed control method provides excellent performance.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.3 s.108
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• pp.298-306
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• 2006

In our previous paper, we developed a robust saturation controller for the linear time-invariant (LTI) system involving both actuator's saturation and structured real parameter uncertainties. This controller can only guarantee the closed-loop robust stability of the system in the presence of actuator's saturation. But we cannot analytically make any comment on control performance of this controller. In this paper, we suggest a method to use linear matrix inequality (LMI) optimization problem which can analytically explain control performance of this robust saturation controller only in nominal system. The availability of design method using LMI optimization problem for this robust saturation controller is verified through a numerical example for the building with an active mass damper (AMD) system.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.49 no.10
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• pp.572-581
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• 2000

When the manipulator consisting of high ratio gear reducers at its joints is used as the slave manipulator in teleoperated systems, its dynamic characteristics is much slower than that of the master manipulator and it is likely to encounter the saturation in the input magnitude. The control input saturation generates an windup phenomenon that the system stability and position tracking performance of the slave manipulator are to be deteriorated. This paper proposes an force reflecting control scheme and its design method which compensates the control input saturation with absolute stability. The proposed scheme is shown to give a stable force reflection while compensating for control input saturation effectively.

• Smart Structures and Systems
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• v.8 no.5
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• pp.449-470
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• 2011

During the last thirty years many structural control concepts have been proposed for the reduction of the structural response caused by earthquake excitations. Their research and implementation in practice have shown that seismic control of structures has a lot of potential but also many limitations. In this paper the importance of two practical issues, time delay and saturation effect, on the performance of controlled structures, is discussed. Their influence, both separately and in interaction, on the response of structures controlled by a modified pole placement algorithm is investigated. Characteristic buildings controlled by this algorithm and subjected to dynamic loads, such as harmonic signals and actual seismic events, are analyzed for a range of levels of time delay and saturation capacity of the control devices. The response reduction surfaces for the combined influence of time delay and force saturation of the controlled buildings are obtained. Conclusions regarding the choice of the control system and the desired properties of the control devices are drawn.

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.2 s.48
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• pp.83-90
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• 2006

In active vibration control of building, controller design considering both control input saturation of controller and parameter uncertainties of building is needed. In our previous research, we proposed a robust saturation controller which guarantees robust stability and control performance of the uncertain linear time-invariant system in the presence of control input saturation. In this paper, the availability of the robust saturation controller for the building with an active mass damper (AMD) system is verified through experimental tests. Experimental tests are carried oui using a two-story building model with a hydraulic-type AMD.

• Korean Chemical Engineering Research
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• v.58 no.3
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• pp.390-395
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• 2020

For some processes with saturations, economical operating points are on the saturation edges. Traditional feedback controllers cannot be used to regulate such processes on the saturation edges because there are abrupt dynamics changes and no feedback information at saturations. Optimization-based methods such as the model predictive control can treat this control problem without difficulty when the saturation levels and dynamics are known and not varying. Otherwise, an adaptation scheme to track the saturation levels and dynamics should be included. Here, for very simple methods to treat this control problem, two control methods based on the recent slope seeking method and the relay feedback method are proposed. Their performances are evaluated with simulations applying them to a second order liquid level system with saturation. Simulations show that these proposed control methods can find and maintain operating point of the saturation edge under 5% relative error.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.425-425
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• 2000

The heavy duty power manipulate generally has high ratio gear reducers at its joints. When it is used as a slave manipulator in the teleoperation system, therefore, the control input saturates frequently and its tracking performance and stability ate also likely to be deteriorated. This paper proposes a force reflecting control scheme for the manipulator with control input saturation. A series of experiments are shown to give excellent tracking performance with force reflection regardless of control input saturation.