• Journal of the Computational Structural Engineering Institute of Korea
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• v.17 no.4
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• pp.343-350
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• 2004

This study is on control gain estimation of energy dissipation control algorithms. Velocity feedback saturated, bang bang, and energy gain control algorithms are proposed based on the Lyapunov stability theory and their performances are evaluated and compared. Saturation problem is considered in the design of the velocity feedback saturated and energy-gain control algorithms, and chattering problem in bang bang control is solved by using boundary layer. Numerical results show that the proposed control algorithms can dissipate the structural energy induced by wind loads efficiently.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.3 s.120
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• pp.264-273
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• 2007

A smart panel with structural sensors and actuators for minimizing noise radiation or transmission is described in the paper with the concept of active structural acoustical control. The sensors and actuators are both quadratically shaped piezoelectric polyvinylidene fluoride(PVDF) Polymer films to implement a volume velocity sensor and uniform force actuator respectively. They are collocated on either side of the panel to take advantage of direct velocity feedback(DVFB) strategy, which can guarantee a robust stability and high performance as long as the sensor-actuator response is strictly positive real(SPR). However, the measured sensor-actuator response of the panel showed unexpected result with non-SPR property. In the paper, the reason of the non-SPR property is investigated by theoretical analysis, computer simulation and experimental verification. The investigation reveals that the arrangement of collocated piezoelectric PVDF sensor and actuator pair on a panel is not relevant to get a high feedback gain and good performance with DVFB strategy.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.12
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• pp.1256-1263
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• 2004

Output feedback passivation problem is studied when the given system is not minimum-phase or does not have relative degree one. Using a parallel connection with an additional dynamics, the authors provide a dynamic output feedback control law which renders the composite system passive. Sufficient conditions are presented under which the composite system is output feedback passive. As an application of the dynamic passivation scheme, a point-to-point control law for a flexible joint robot is presented when only the position measurements are available. This provides an alternative way of replacing the role of the velocity measurements for the proportional-derivative (PD) feedback law. The performance of the proposed control law is illustrated in the simulation studies of a manipulator with three revolute elastic joints.

• Earthquakes and Structures
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• v.6 no.2
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• pp.217-235
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• 2014

In this paper, different feedback control strategies are presented for active seismic control using proportional-integral-derivative (PID) type controllers. The parameters of PID controller are found by using an numerical algorithm considering time delay, maximum allowed control force and time domain analyses of shear buildings under different earthquake excitations. The numerical algorithm scans combinations of different controller parameters such as proportional gain ($K_p$), integral time ($T_i$) and derivative time ($T_d$) in order to minimize a defined response of the structure. The controllers for displacement, velocity and acceleration feedback control strategies are tuned for structures with active control at the first story and all stories. The performance and robustness of different feedback controls on time and frequency responses of structures are evaluated. All feedback controls are generally robust for the changing properties of the structure, but acceleration feedback control is the best one for efficiency and stability of control system.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2005.04a
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• pp.538-547
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• 2005

This paper presents the shaking table testing method, only using building specimen as an experimental part taking into account the dynamic soil-structure interaction based on the substructure method. The Parmelee's soil stiffness is used as an assumed soil model in here. The proposed methodologies are summarized as: (1) Acceleration feedback method is the one that the shaking table is driven by the motion, corresponding to the acceleration at foundation of the total SSI system. This is found by observing the fed-back accelerations of superstructure and using the interaction force based on the acceleration formulation. (2) Velocity feedback method is the one that the shaking table is driven by the motion, corresponding to the velocity at foundation of the total SSI system. This is found by observing the fed-back accelerations of superstructure and using the interaction force based on the velocity formulation. The applicability of the proposed methodologies to the shaking table test is investigated and experimentally verified in this paper.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.494-497
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• 2005

Direct velocity feedback (DVFB) control with a collocated distributed actuator and point sensor pair is known that it offers a good stability with high performance when the control strategy is applied at the suppression of structural vibration. Also decentralized control method introduced to offer to reduce implementaion effort and malfunction due to failure in sensors and actuators of control system has become an important position in DVFB. In this paper, the decentralized control is compared with centralized control in terms of vibrational velocity reduction in a clamped-clamped beam.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.291-298
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• 2000

This paper describes a theoretical and experimental investigation into an active vibration isolation system in which four electromagnetic actuators are installed in parallel with each of four passive mounts placed between a piece of equipment and a vibrating base structure. Decentralised velocity feedback control is employed, where each actuator is operated independently by feeding back the absolute equipment velocity at the same location. Although one end of each actuator acts at the sensor positions on the equipment, the control system is not collocated because of the reactive forces acting on the flexible base structure, whose dynamics are strongly coupled with the mounted equipment. Isolation of low frequency vibration is considered where the equipment can be modelled as a rigid body and the mounts as lumped parameter springs and dampers. Control mechanisms are discussed, and some experimental and simulation results are reported.

• Transactions on Control, Automation and Systems Engineering
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• v.4 no.1
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• pp.38-42
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• 2002

Conditions are discussed for operating a dissymmetric human master-small (or micro) slave system in best (large position gain-small velocity gain) conditions allowing higher operator dexterity when real effects (joint compliance, link flexion delay and transmission distortion) are taken into account. It is shown that position PD feedback law advantage for ideal case no longer holds, and that more complicated feedback law depending on real effects has to be implemented with adapted transmission line. Drawback is slowdown of master slave interaction, suggesting to use more advanced predictive methods for the master and more intelligent control law for the slave.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.337-341
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• 2003

This paper provides a design method for a dynamic output feedback controller which stabilizes a class of linear time invariant systems. We suppose all the states of the given system is not measurable and only the outputs are used to stabilize the system. The systems considered cannot be stabilized by a static output feedback only. In the scheme we first assume that the given system can be stabilized by a state feedback composed of its output, velocity of the output and its higher order derivative terms. Instead of using the derivatives of the output, however, a dynamic system is constructed systematically which replaces the role of the derivative terms. Then, a high-gain output feedback stabilizes the composite system together with the newly constructed system. The performance of the proposed control law is illustrated in the comparative simulation studies of a numerical example with an observer-based control law.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10a
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• pp.145-148
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• 1990

In this paper, the problem of designing a feedback controller for a robotic manipulator, which is activated by a D.C. motor through a gear train and a flexible shaft or chain, is considered. When the response of the closed loop control system is relatively slow, a satisfactory controller may be designed as a PID controller. As the speed of the control system increases, however, the spring effect of the linkage becomes profound, and as a result, the transient response exhibits a substantial oscillation. To eliminate this oscillation, it is necessary to design the controller based on at least a fourth order system model. This, in turn, requires the feedback of the entire state variables. In practice, however, only the position of the manipulator and the velocity of the motor are readily measurable. The state variable reconstruction method or a state observer cannot be used because of the system nonlinearities such as the Coulomb frictions. In this study, an alternative controller, which is based on delayed feedback of the output variable only, is proposed, and a successful delayed feedback controller is designed and implemented on an actual experimental manipulator.