Active vibration control

About: Active vibration control is a research topic. Over the lifetime, 6770 publications have been published within this topic receiving 76599 citations. The topic is also known as: active vibration damping.

Neural Network Based Hysteresis Compensation of Piezoelectric Stack Actuator Driven Active Control of Helicopter Vibration

Abstract: Piezoelectric Stack Actuators (PSAs) have become promising actuators for active control of helicopter fuselage vibration owing to their large output force, rapid response speed, wide working frequency and light weight. However, the hysteresis nonlinearity of PSA has negative influence on the performance of PSA-driven active vibration control. In this paper, to improve the performance of PSA-driven active control of helicopter vibration, the hysteresis nonlinear neural network and hysteresis compensation neural network of PSA have been established based on the Nonlinear Auto Regression eXogenous (NARX) model. The PSA's voltage-displacement relations under two-harmonic actuations were used for training the neural networks of hysteresis nonlinearity and hysteresis compensation. Then the compensation neural network for PSA's hysteresis was integrated into an active control system for helicopter vibration. The results of experimental investigation performed on a scale model of a representative helicopter fuselage floor structure indicate that the neural network based hysteresis compensation of PSA for active control of helicopter vibration can effectively reduce vibration of the scaled frame structure and can reduce more vibration than without compensation.

Vibration control apparatus

Abstract: A vibration control apparatus comprises a vibration member having a surface with a resonance point. A piezoelectric element is adhered to the surface of the vibration member. A drive apparatus is connected to the piezoelectric element via an impedance element for exciting the piezoelectric element with an A.C. signal. A feedback circuit is connected between the piezoelectric element and the drive apparatus. The feedback circuit picks out the components of a voltage on the piezoelectric element caused by a strain of the piezoelectric element and feeds this voltage back to control the drive apparatus. The inventive vibration control apparatus may be incorporated in a gyro to simplify the construction of the gyro.

Coordinate measuring machine with vibration dampening system

Abstract: A vibration dampening system particularly for use in a gantry-type coordinate measuring machine. The vibration dampening system includes a vibration damper in the gantry structure, a vibration damper in the Z-rail, and means in the supports for the base for dampening vibrations, all of which work together cooperatively to damp vibrations in the coordinate measuring machine. The vibration damper in the gantry structure and in the Z-rail each comprises a substantial mass suspended by pads of material having high energy absorbence and a low rebound resilience. The vibration dampening means in the table means includes a layer of material which is highly energy absorbent and has a low rebound resiliency, and which is disposed between two rigid plates positioned between each supporting leg of the table and an underlying floor. The vibration dampening system is tuned to provide maximum energy absorbency at major modes of vibrations in the machine during acceleration and deceleration.

Control of Forced Vibration Using Multi-Electrode Electro-Rheological Fluid Dampers

Abstract: Vibration control of cylindrical, electro-rheological fluid (ERF) dampers were studied. Single- as well as multi-electrode cylindrical ERF dampers were designed, built and tested under a forced vibration motion. Closed-loop, on-line control systems utilizing bang-bang and linear proportional controller were implemented to control the damping capacity of the ERF dampers. In addition, the designs were modified to reduce the required activation voltage. These modifications include increasing the electrode surface area as well as the number of electrodes. The damping ability of the dampers was further enhanced by using two identical dampers in series connection.