Papers by Keyword: Active Vibration Control

Abstract: Blanking noise and blanking vibration are causes of pollution. At the same time, blanking vibration disturbs the high precision of a press work product, and shortens the life expectancy of the press machine and the press die. Recently, the use of a servo press has been developed to improve these problems, using low speed blanking and pulse vibration banking. However, these methods lengthen the blanking time, so it is necessary to control the servo press properly in the case of blanking. In this study, we describe a principle for the reduction of blanking vibration when using a servo press, and we propose an active vibration control method for the reduction of blanking vibration. We used a crank servo press of 450kN in an experiment, which has a pulse motion of 10Hz. We conducted a simulation and an experiment of blanking using an active vibration control method, which we named “counter pulse blanking.” We confirmed that counter pulse blanking is effective in reducing vibration as a result of the simulation and the experiment.

Abstract: A cable-net reflector is fist introduced and then the state space representation is derived based on the finite element model. Modal analysis is carried out for the purpose of vibration control in modal space. The first several natural frequencies and vibration modes are obtained to analyze the vibration characteristics. The optimal control theory based on LQR with full state feedback is used for the control problem. Numerical simulations of the impulse disturbance response and the frequency response are implemented. Also, the contrast between the uncontrolled and controlled cases is illustrated. The theoretical results confirm the effectiveness of the proposed active control strategy for the vibration suppress of the cable-net reflector.

Abstract: An active noise-canceling casing is very attractive for reduction of sound generated bydevices. Such casing can provide good noise reduction for low frequencies, where a passive barrierwould be too thick for practical use. The classical active noise control approach, where the goal is tominimize the sound pressure level around multiple microphones outside the casing can be used. However,it requires placing external microphones, what makes the overall technical solution not acceptedfor many applications. The active vibration control, where the goal is to minimize vibrations of allplates, requires only sensors on the plates. However, in this solution, in turn, noise reduction resultsare worse. This paper presents employment of the idea of the virtual microphone-based approach toimprove results from the system based on vibration sensors only, which are used to estimate acousticpressure at specific locations in the acoustic field. By using a two-stage structure, the system is tunedto reconstruct the same vibrations of the plates, which were present when the acoustic pressure wereminimized directly in the square sense. A laboratory active noise-canceling casing used for experimentsis made of 5 actively controlled aluminum plates mounted on a steel frame. It is passivelyisolated from the floor. On each plate, three electrodynamical actuators are installed. The controlsystem is experimentally verified and obtained results are reported.

Abstract: This paper presents a method for the active noise and vibration control (ANC/AVC) of harmonically related nonstationary disturbances using varying-sampling-time linear parameter-varying (LPV) controller. The frequencies are assumed to be known and varying within given ranges and they are multiples of one fundamental frequency.

Abstract: The idea of active casing is an approach to reduce device and machinery noise by controlling vibration of casing walls. The sound insulation efficiency of this technique for a single-plate casing was confirmed by the authors in previous publications. However, under specific circumstances, a dedicated double-panel structure can yield even higher noise reduction. The aim of this paper is to propose and evaluate by means of laboratory experiments the performance of a double-panel casing in comparison with a single-panel casing. An adaptive control strategy based on the Least Mean Square (LMS) algorithm is used to update control filter parameters. A low-frequency noise in the range up to 250 Hz is considered. Obtained results are reported, discussed, and conclusions for future research are drawn.

Abstract: In this study we investigated the dynamical behavior of aircraft wings and using piezoelectric actuation we implemented active vibration control. The aircraft wing is modeled as a thin-walled composite beam having a cross section of diamond shaped. The dynamic response of the beam under varying proportional and velocity feedback gain parameters is obtained and shown to be enhanced with optimal control procedure, minimizing the control effort and response.

Abstract: Experimental studies are conducted on active vibration control using self-tuning proportional integral derivative and self-tuning proportional iterative learning algorithm control schemes to suppress vibration on a flexible beam via real-time computer control. An experimental rig is developed to investigate controller performance when a change in the dynamic behavior of the flexible beam system occurs. The performance of the self-tuning control schemes is validated experimentally and compared with that of conventional control schemes through the use of an iterative learning algorithm. Experimental results clearly reveal the effectiveness and robustness of the self-tuning control schemes over conventional control schemes.

Abstract: This paper investigates the effectiveness of piezostack actuator in attenuating the frequency dependent excited vibration of a suspended handle. A shaker is used to produce a base excitation to the suspended handle and a piezostack actuator is used to generate the vibration cancellation for the handle. The investigation covers vibration operating frequency from 50 to 500 Hz. This study also looked at the initial performance of piezostack actuator for the AVC system. A PID controller is design to generate the counter voltage for the piezostack actuator to attenuate the vibration of the handle. The results show that the highest vibration attenuation of the suspended handle occurred at operating frequency of 450 Hz with 90 % of vibration attenuation and the lowest at 50 Hz with 2.4 % of vibration attenuation.

Abstract: Piezoelectric smart structure is chosen as the piezoelectric material sensing and driving elements, and control system combine to form a structure with identification, analysis, judgment, action, and other functions. The active vibration control for structures is an important research direction.

Abstract: According to the actuating requirement of active isolation platform, magnetic circuit and moving coil structure of non-contact installing type of voice coil actuator was designed, and the magnetic filed of the working gap was simulated. A programmable current supply used for driving the voice coil actuator was designed and the circuit was simulated. Output force performance of the designed voice coil actuator driving by programmable current supply was tested. The test results indicate that the designed voice coil actuating system has excellent output force performance at low frequency band with good linearity and low noise and waviness. The measured output force coefficient of the voice coil actuator matches with the designed value, and the designed actuating system can meet the requirement of active isolation platform.