• Journal of KSNVE
• /
• v.7 no.6
• /
• pp.1007-1013
• /
• 1997

This paper presents active vibration control scheme of multi-mode forced vibration using piezocetamic sensors and actuators. The control scheme adopted is the Positive Position Feedback (PPF) control. Among various vibration control techniques. PPF control technique makes use of generalized displacement measurements to accomplish the vibration suppression. Two independent controllers are implemented to control the first and the second modes of the beam under external excitation. Experimental results for various damping ratios and feedback gains of the PPF controllers are compared with respect to the contorl efficiency. The results indicate that steady state vibration under wide band excitation can be controlled effectively when multiple sets of PZT sensors and actuators were used with PPF control technique.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 1997.04a
• /
• pp.407-412
• /
• 1997

There has been a recent surge of research interest on the smart structure. This paper presents active vibration control scheme of multi-mode forced vibration using piezoceramic sensors/actuators. The control scheme adopted is the Positive Position Feedback control. Among various vibration control techniques, PPF control technique makes use of generalized displacement measurements to accomplish vibration suppression. Two independent controllers are implemented to control the first and the second modes of the beam under external excitation. Experimental results for various damping ratio and feedback gains of the PPF controllers are compared with respect to the control efficiency. The results indicate that steady state vibration under wideband excitation can be controlled effectively when multiple sets of PZT sensors/actuators were used with PPF control technique.

• 제어로봇시스템학회:학술대회논문집
• /
• 2003.10a
• /
• pp.1392-1397
• /
• 2003

This paper deals with a control technique of eliminating the transient vibration of a twin-drive geared mechanical system. This technique is based on a model-based control in order to establish the damping effect at the driven machine part. The control model is composed of reduced-order electrical and mechanical parts. This control model estimates a load speed converted to the motor shaft. The difference between the estimated load speed and the motor speed is calculated dynamically and it is added to the velocity command to suppress the transient vibration generated at the load. This control technique is applied to a twin-drive geared system with backlash. In the previous work, the performance of this control method is examined by simulations. In this paper, the effectiveness of this control technique is verified by experiments. The settling time of the residual vibration generated at the loading inertia can be shortened down to about 1/2 of the uncompensated vibration level.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.13 no.5
• /
• pp.348-356
• /
• 2003

Active vibration control algorithms for the compensator and proto-type testing system have been developed for the suppression of vibrations from the reciprocating engines. At first, the developed algorithm determines optimal control vibration phases by detecting vibration responses of the engine without and with compensator, and then performs the continuous optimal control functions by tracking the change of the vibration frequency and phase. This algorithm is comparatively simple. robust for the external excitations and needless of supplementary operation since the control process is serially carried out. To validate the performance of compensator and algorithm, testing system including excitation device are constructed and tested, and the reductions of vibration levels are observed over than 80 % of the uncontrolled levels at various frequency ranges.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2004.10a
• /
• pp.282-285
• /
• 2004

The main purpose of this study is the vibration suppression of rotating composite blade containing distributed piezoelectric sensors and actuators. The blade is modeled by thin-walled, single cell composite beam including the warping function, centrifugal force, Coriolis acceleration and piezoelectric effect. Further, the numerical study is performed m ing finite element method. The vibration of composite rotor is suppressed by piezocomposite actuators and PVDF sensors that are embedded between composite layers. A velocity feedback control algorithm coupling the direct and converse piezoelectric effect is used to actively control the' dynamic response of an integrated structure through a closed control loop. Responses of the rotating blade are investigated. Newmark time integration method is used to calculate the time response of the model. In the numerical simulation, the effect of parameters such as rotating speed, fiber orientation of the blade and size of actuators are studied in detail.

• Earthquakes and Structures
• /
• v.7 no.6
• /
• pp.1025-1044
• /
• 2014

In this paper, a systematic technique is proposed for the optimal placement and design of nonlinear dampers for building structures. The concept of Output Frequency Response Function (OFRF) is applied to analytically represent the output frequency response of a building frame where nonlinear viscous dampers are fitted for suppression of vibration during earthquakes. An effective algorithm is derived using the analytical representation to optimally determine the locations and parameters of the nonlinear dampers. Various numerical examples are provided to verify the effectiveness of the optimal designs. A comparison of the vibration suppression performance with that of the frame structure under a random or uniform damping allocation is also made to demonstrate the advantages of the new designs over traditional solutions.

• Journal of Institute of Control, Robotics and Systems
• /
• v.14 no.6
• /
• pp.564-572
• /
• 2008

The performance of the direct adaptive time-delay command shaping filter depends on the select time-delay. In the previously introduced direct adaptive command shaping filter, however, the time-delay value is fixed and only the magnitudes of the impulses are learned. In this paper, the authors introduce a new scheme to adapt the time-delay which is to be used in conjunction with the direct adaptive command shaping for the improved vibration suppression in flexible motion system. In order to formulate the time-delay adaptation scheme, the authors have analyzed the effect of the time-delay value on the performance of the direct adaptive command shaping filter. By modifying the direct adaptation formula based on the analysis result the authors have established a set of equations to adapt the time-delay toward the optimal value. Simulation results show the effectiveness of the proposed time-delay adaptation approach for the improved vibration suppression.

• Proceedings of the KSME Conference
• /
• 2000.04a
• /
• pp.499-504
• /
• 2000

Since large space structures(LSS) such as a space station, a solar power station satellite, etc., are theoretically distributed parameter and infinite-dimensional system, they have to be modeled into large finite-dimensional systems for control system design. Besides, there are fundamental problems in active vibration control of the large flexible structures. For example, a modeled large finite-dimensional system must be controlled with a much smaller dimensional controller. This causes the spillover phenomenon which degrades the control performances and reduces the stability margin. Furthermore, it may destabilize the entire feedback control system. In this paper, we proposed a novel control method for spillover suppression in the control of large flexible structures by using eigenstructure assignment. Its effectiveness in spillover suppression is investigated and verified by the numerical experiments using an example of the simply supported flexible beam which is modeled to have four controlled modes and eight uncontrolled modes.

• 제어로봇시스템학회:학술대회논문집
• /
• 2002.10a
• /
• pp.50.2-50
• /
• 2002

1. Introduction 2. Reduced-Order Model of Robot System 3. Model-Based Control 4. Simulation Results 5. Experimental Results and Considerations 6. Conclusions

• Journal of Astronomy and Space Sciences
• /
• v.14 no.2
• /
• pp.367-374
• /
• 1997

Slewing maneuver and vibration suppression control of flexible spacecraft model by Lyapunov stability theory are considered. The specific model considered in this paper consists of a rigid hub with an elastic appendage attached to the central hub and tip mass. Attitude control to point and stabilize single axis using reaction wheel type device is tested. To control all flexible modes is so critical to designing an active control law. We therefore considered an direct output feeback control design by using Lyapunov stability theory. It is shown that the ouput feedback control law design with proposed configuration gives satisfactory result in slewing performance and vibration suppression control.