Motion and Vibration Control of a Flexible Transportation System Used Piezoelectric Films as Sensor for Vibration Detection

Author(s):  
Masato Nishikiori ◽  
Toru Watanabe ◽  
Kazuto Seto

This paper deals with motion and multi-modes of vibration control of a flexible transportation system. In order to reduce a settling time from one position to another one, the vibration control is remarkably important on the transportation system. Since transportation system moves long distance, no limit in the measuring range of the sensor is required. For the purpose, piezoelectric films pasted on flexible structures are used as the point sensor to detect vibrations. To control the first two vibration modes, the reduced-order physical modeling method proposed by authors is applied and the control system is designed by LQ control approach. Control experiments demonstrate that the settling time is well shortening by controlling many-modes of vibration in addition to motion.

Author(s):  
Kazuto Seto ◽  
Susumu Kondo ◽  
Katsuhiko Ezure

Abstract This paper examines the vibration control of a flexible structure using a hybrid dynamic absorber. A new method for modeling flexible structures with distributed parameters using a reduced-order model with lumped parameters is specified. Both prevention of spillover and physical correspondence at the modeling points are taken into consideration. Due to restrictions of controller design it is necessary to employ reduced-order models of flexible structures when using LQ control theory to control vibration. By ignoring higher mode orders model reduction may invite vibration instability called spillover. In order to prevent spillover nodes of higher-order vibration modes are selected as modeling points. The effectiveness of this method is demonstrated by applying vibration control to a flexible tower-like structure. In addition the robustness of the control system is tested by placing the sensors and absorbers at points different from those selected by the model.


Author(s):  
Sourav Kundu ◽  
Kentaro Kamagata ◽  
Shigeru Sugino ◽  
Takeshi Minowa ◽  
Kazuto Seto

Abstract A Genetic Algorithm (GA) based approach for solution of optimal control design of flexible structures is presented in this paper. The method for modeling flexible structures with distributed parameters as reduced-order models with lumped parameters, which has been developed previously, is employed. Due to some restrictions on controller design it is necessary to make a reduced-order model of the structure. Once the model is established the design of flexible structures is considered as a feedback search procedure where a new solution is assigned some fitness value for the GA and the algorithm iterates till some satisfactory design solution is achieved. We propose a pole assignment method to determine the evaluation (fitness) function to be used by the GA to find optimal damping ratios in passive elements. This paper demonstrates the first results of a genetic algorithm approach to solution of the vibration control problem for practical control applications to flexible tower-like structures.


Author(s):  
Kazuto Seto ◽  
Yoshihiro Toba ◽  
Fumio Doi

Abstract In order to realize living comfort of tall buildings by reducing the vibration of higher floors by strong winds, this paper proposes a new method of vibration control for flexible structures with a large scale. The higher a tall building the lower its natural frequency. Since obtaining sufficient force to control the lower frequency vibrations of tall buildings is a difficult task, controlling the vibration of ultra-tall buildings using active dynamic absorbers is nearly impossible. This problem can be overcome by placing actuators between a pair of two or three ultra-tall buildings and using the vibrational force of each building to offset the vibrational movement of its paired mate. Therefore, it is able to obtain enough control force under the low frequency when the proposed method is used. In this paper, a reduced-order model expressed by 2DOF system under taking into consideration for preventing spillover instability is applied to control each flexible structure. The LQ control theory is applied to the design of such a control system. The effectiveness of this method is demonstrated theoretically as well as experimentally.


Author(s):  
Keisuke Takemoto ◽  
Masato Mori ◽  
Toru Watanabe ◽  
Kazuto Seto

This paper shows a lumped modeling approach and a motion and vibration control method for a transportation system. The modeling approach is made on the premise that motion influences vibration, but that vibration doesn’t influence motion. To obtain well suppressed vibration and a robustness for the system, LQI control is adopted. It is shown that this theory has superior robustness for in motion and vibration control with variations of the parameters [1]. The control effectiveness is demonstrated through simulation experiments. The vibration modes that occur accordingly become flexible might cause a spillover instability problem. Thus, the purpose of the research is to control such vibration and motion using the modeling method presented by Seto, called the “reduced order physical modeling method” [2]. Computer simulation and control experiments are carried out and the effectiveness of the procedures presented is investigated.


Author(s):  
Ehsan Omidi ◽  
S. Nima Mahmoodi

This paper discusses the concept of a new methodology for active vibration control of flexible structures using consensus control of network systems. In the new approach, collocated actuation/sensingpatches communicate with one another through a network with certain directed topology. A virtual leader is assigned to enforce the vibration amplitude at the place of each agent to zero. Since the modal states of the system are not available for the vibration control task, individual optimal observers are designed for each agent first. After describing the controller and examining the stability of the system, controller performance is verified using a clamped-clamped thin aluminum beam. According to the obtained numerical results, the new control approach successfully suppresses the vibration amplitudes, while the consensus design ensures that all agents are synchronized during the performance.


1994 ◽  
Vol 6 (4) ◽  
pp. 292-297
Author(s):  
Kazuto Seto ◽  
◽  
Katsuhiko Ezure ◽  

This paper proposes an experimental study on the arrangements between the setting points of an actuator and sensor for the vibration control of a flexible structure, when a vibration controller is mounted at an arbitrary position on the structure. The important vibration mode of the structure to be controlled is its first mode, because it is excited most sensitively by strong winds. It is therefore necessary to make a reduced-order model represented by a one-degree-of-freedom system at an arbitrary location, in consideration of preventing spillover instability. In this paper, non-observability is used for making the reduced-order model, and the LQ control theory is used for controller design. For controlling vibration, a reduced-order model is constructed at the setting point of a hybrid dynamic absorber, and a displacement sensor is set at the vibration node of the second vibration mode. Then, the setting point of the sensor is changed to compare control effects by means of this model. It is demonstrated experimentally that a hybrid dynamic absorber, designed by this method, is capable of controlling vibration well without causing spillover instability. In addition, it is considered that the setting point of the sensor influences the robustness of the control system.


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