Active Vibration Control for the Closed Loop Flexible Mechanisms Combined the Feedback and Feed-Forward Strategy: Part 2 — Control Design and Simulation

2000 ◽  
Author(s):  
Zhang Xianmin ◽  
Chao Changjian
Keyword(s):  
Equations Of Motion ◽  
Active Vibration Control ◽  
Elastic Vibration ◽  
Linkage Mechanism ◽  
Control Laws ◽  
Feed Forward ◽  
Feed Forward Control ◽  
Active Vibration ◽  
Four Bar Linkage ◽  
Flexible Mechanisms

Abstract On the basis of the complex mode theory and the equations of motion of the flexible mechanisms developed in part 1, a hybrid independent modal controller is presented, which is composed of state feedback and disturbance feed-forward control laws. As an illustrative example, the strategy is used to control the elastic vibration response of a four-bar linkage mechanism. The imitative computational result shows that the vibration is efficiently suppressed.

Active Vibration Control for the Closed Loop Flexible Mechanisms Combined the Feedback and Feed-Forward Strategy: Part 1 — Modelling

2000 ◽  
Author(s):  
Zhang Xianmin ◽  
Chao Changjian
Keyword(s):  
Variational Approach ◽  
High Speed ◽  
Closed Loop ◽  
Equations Of Motion ◽  
Active Vibration Control ◽  
Active Vibration ◽  
Flexible Mechanism ◽  
Elastodynamic Response ◽  
Coupling Terms ◽  
Flexible Mechanisms

Abstract A methodology for suppressing the elastodynamic response of high speed closed loop flexible mechanisms with piezoelectric actuators and sensors are developed. In this part, a mixed variational approach with Hamilton’s principle is developed to derive the equations of motion for the closed loop flexible mechanism systems which describes the motion of the mechanisms and the behavior of the piezoelectric apparatus. This model includes both the rigid-body and the elastic motion coupling terms and the elasto-dynamics and piezoelectricity coupling terms as well as the effects of the actuators and sensors upon the mass and stiffness of the system.

Active Vibration Control of Smart Hull Structure Using Piezoelectric Composite Actuators

2008 ◽  
Vol 47-50 ◽  
pp. 137-140 ◽  
Author(s):  
Jung Woo Sohn ◽  
Seung Bok Choi
Keyword(s):  
Vibration Control ◽  
Fiber Composite ◽  
Equations Of Motion ◽  
Active Vibration Control ◽  
Piezoelectric Composite ◽  
Governing Equations ◽  
Linear Quadratic ◽  
Element Analysis ◽  
Hull Structure ◽  
Active Vibration

In this paper, active vibration control performance of the smart hull structure with Macro-Fiber Composite (MFC) is evaluated. The governing equations of motion of the hull structure with MFC actuators are derived based on the classical Donnell-Mushtari shell theory. Subsequently, modal characteristics are investigated and compared with the results obtained from finite element analysis and experiment. The governing equations of vibration control system are then established and expressed in the state space form. Linear Quadratic Gaussian (LQG) control algorithm is designed in order to effectively and actively control the imposed vibration. The controller is experimentally realized and control performances are evaluated.

Active Vibration Control Based on Self-Sensing for Unknown Target Structures by Direct Velocity Feedback With Adaptive Feed-Forward Cancellation

2013 ◽  
Author(s):  
Shota Yabui ◽  
Itsuro Kajiwara ◽  
Ryohei Okita
Keyword(s):  
Control System ◽  
Vibration Control ◽  
Control Method ◽  
Active Vibration Control ◽  
Mechanical Resonance ◽  
Velocity Feedback ◽  
Feed Forward ◽  
Periodic Disturbance ◽  
Active Vibration ◽  
The Voice

This paper presents active vibration control based on self-sensing for unknown target structures by direct velocity feedback (DVFB) with enhanced adaptive feed-forward cancellation (AFC). AFC is known as an adaptive control method, and the adaptive algorithm can estimate a periodic disturbance. In a previous study, an enhanced AFC was developed to compensate for a non-periodic disturbance. An active vibration control based on self-sensing by DVFB can suppress mechanical resonance by using relative velocity between the voice coil actuator and a target structure. In this study, the enhanced AFC was applied to compensate disturbance for the self-sensing vibration control system. The simulation results showed the vibration control system with DVFB and enhanced AFC could suppress mechanical resonance and compensate disturbances.

scholarly journals Experimental Study of Active Vibration Control of Planar 3-RRR Flexible Parallel Robots Mechanism

2016 ◽  
Vol 2016 ◽  
pp. 1-17 ◽  
Author(s):  
Qinghua Zhang ◽  
Xianmin Zhang ◽  
Junyang Wei
Keyword(s):  
Strain Rate ◽  
Vibration Control ◽  
Active Vibration Control ◽  
Elastic Vibration ◽  
Parallel Robots ◽  
Flexible Link ◽  
Flexible Links ◽  
Rate Feedback ◽  
Active Vibration ◽  
General Motion

An active vibration control experiment of planar 3-RRR flexible parallel robots is implemented in this paper. Considering the direct and inverse piezoelectric effect of PZT material, a general motion equation is established. A strain rate feedback controller is designed based on the established general motion equation. Four control schemes are designed in this experiment: three passive flexible links are controlled at the same time, only passive flexible link 1 is controlled, only passive flexible link 2 is controlled, and only passive flexible link 3 is controlled. The experimental results show that only one flexible link controlled scheme  suppresses elastic vibration and cannot suppress the elastic vibration of the other flexible links, whereas when three passive flexible links are controlled at the same time, they are able to effectively suppress the elastic vibration of all of the flexible links. In general, the experiment verifies that a strain rate feedback controller is able to effectively suppress the elastic vibration of the flexible links of plane 3-RRR flexible parallel robots.

Active Vibration Control Method for Space Mechanical Structure with Piezostacks

2013 ◽  
Vol 198 ◽  
pp. 433-438
Author(s):  
Andrzej Piotr Koszewnik
Keyword(s):  
Control System ◽  
Vibration Control ◽  
Control Method ◽  
Active Vibration Control ◽  
Three Dimensional ◽  
Control Laws ◽  
Distributed Parameters ◽  
Short Period ◽  
Lqr Controller ◽  
Active Vibration

Mechanical structures are spatial, three-dimensional (3D) systems of distributed parameters. They present quite complicated plants, if methods of control systems theory are applied. The design process of the vibration control system for such plants is extremely difficult and requires an extensive heuristic knowledge. The subject of the control system is to eliminate the vibrations of the free end at the plane parallel to the foundation Similar problems are met, when the stabilization of robot arms, antennas, satellite solar batteries or slender skyscrapers is considered. In the paper we have presented the 3D bar structure with sticked parallel two piezo-stacks into bars. Recall piezo-elements are actuators, but sensors are two eddy-current sensors located in near free end the structure in perpendicular directions X and Y. Thus the whole structure is TITO (Two Input Two Output) system. For such system the control law was designed with used LQR controller. Above controller was designed for coupled and decoupled system also. In both case a correct damp and very short period of the vibration were criteria to choose the controller parameters. All investigations were carried out in two steps. In the first step control laws were designed in computer simulation. In the second step these control laws were verified experimentally on the laboratory stand by using DSP. Finally, desired control laws were compared.

Active Vibration Control of Beams By Combining Precompressed Layer Damping and ACLD Treatment: Theory and Experimental Implementation

2011 ◽  
Vol 133 (6) ◽  
Author(s):  
Sanjiv Kumar ◽  
Rakesh Sehgal ◽  
Rajiv Kumar
Keyword(s):  
Equations Of Motion ◽  
Active Vibration Control ◽  
Flexible Structures ◽  
Constrained Layer Damping ◽  
Linear Quadratic ◽  
Active Constrained Layer Damping ◽  
Active Vibration ◽  
Passive Technique ◽  
Failure Conditions ◽  
Passive Constrained Layer Damping

By attaching initially stressed poly vinyl chloride (PVC) layers on the flexible structures, necessary passive damping can be provided. Using passive constrained layers on these PVC layers, the efficiency can be made even better than ordinary passive constrained layer damping (PCLD) treatment. By using stressed PVC layers, a rich performance in case of circuit failure conditions is always available. An active constraining layer further enhances the damping performance of this passive technique. Precompressed layer damping treatment augmented with active constrained layer damping (ACLD) treatment has been suggested, which has many desirable features as compared to existing pretensed layer damping treatment. Such enhancement in damping performance is not possible by conventional ACLD as well as PCLD techniques. The effect of initial strain (compressive or tensile) and other parameters of the PVC layers on the vibration characteristics of flexible structure have been investigated. The Hamilton principle in conjunction with finite element method is used to derive the differential equations of motion. Using proportional feedback controllers, the complex closed loop eigenvalue problem is developed and solved numerically. The effectiveness of the proposed technique has been validated experimentally using a digital linear quadratic Gaussian controller.

An adaptive anechoic termination for active vibration control

2011 ◽  
Vol 17 (13) ◽  
pp. 2066-2078 ◽  
Author(s):  
E Rustighi ◽  
BR Mace ◽  
NS Ferguson
Keyword(s):  
Adaptive Control ◽  
Active Vibration Control ◽  
Reference Signal ◽  
Flexural Vibration ◽  
Feed Forward ◽  
Reflected Waves ◽  
Resonant Structures ◽  
Propagating Waves ◽  
Active Vibration ◽  
The Cost

The active broadband control of the flexural vibration of a slender structure, in particular a beam, is obtained by the use of an adaptive anechoic termination. The anechoic termination, which absorbs any energy incident upon it, is implemented by applying a force close to one end of the structure. The force is determined by a feed-forward adaptive control that uses estimates of the incident and reflected waves as reference and error signals. Digital filters are implemented to estimate, in real-time, the amplitudes of these waves by filtering the outputs of an array of sensors. The reflected wave is used as the cost function in a filtered-X LMS adaptive control. The use of the propagating waves as reference and error signals also allows the method to be effective for resonant structures, a situation in which conventional approaches fail to be reliable. In order to compare the method with a conventional approach an anechoic termination that uses the primary excitation as reference is also considered. Numerical and experimental results demonstrate the method applied to semi-infinite and finite resonant structures. A broadband reduction of up to 20 dB in the ratio of the reflected and incident powers is demonstrated both numerically and experimentally. The use of the adaptive anechoic termination to reduce the vibration levels in structures is shown to be more effective than other typical feed-forward active control systems. Furthermore, it can be applied to cases where no reference signal, such as the primary excitation, is directly available.

scholarly journals A Parallel Solution Scheme for Inverse Dynamics and its Application in Feed-forward Control of Link Mechanisms

2003 ◽  
Vol 15 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Daigoro Isobe ◽  
◽  
Daisaku Imaizumi ◽  
Youichi Chikugo ◽  
Shunsuke Sato
Keyword(s):  
Inverse Dynamics ◽  
Equations Of Motion ◽  
Open Loop ◽  
Joint Torque ◽  
Entire System ◽  
Two Dimensional ◽  
Feed Forward ◽  
Parallel Solution ◽  
Feed Forward Control ◽  
Solution Scheme

This paper describes a three-dimensional parallel solution scheme for inverse dynamics of link mechanisms, which has already been proposed for the two-dimensional case and applied in several in-plane motions. In this theory, the entire system is subdivided into finite elements and evaluated as a continuum. A single-link structure of a pin joint and a rigid bar is expressed using the Shifted Integration (SI) technique, which is conventionally used in finite element analyses of framed structures. This scheme calculates nodal forces by evaluating equations of motion in a matrix form, and thus information from the entire system can be handled in parallel, which is a very useful characteristic when applied in closed-loop or continuously transforming mechanisms. The obtained nodal forces are then converted into the joint torque in the system. Simple numerical tests on two-dimensional and threedimensional open-loop link mechanisms are carried out for comparison with other schemes. The proposed scheme is implemented in a control system to evaluate the performance in actual control with dynamics compensation, and some control experiments are carried out on an open-loop link mechanism. The results reveal the possibility of using the proposed solution scheme in feed-forward control, independently to the system configuration of link mechanisms.

Simulation Study of Active Vibration Control of Cantilever Beam by Using State and Output Feedback Control Laws

2013 ◽  
Author(s):  
S. M. Khot ◽  
Nitesh P. Yelve ◽  
Raj Nair
Keyword(s):  
Mathematical Model ◽  
Feedback Control ◽  
Vibration Control ◽  
Output Feedback ◽  
Active Vibration Control ◽  
Output Feedback Control ◽  
Full Model ◽  
Control Laws ◽  
Active Vibration ◽  
The Mathematical Model

Undesired noise and vibrations have a detrimental effect in many areas. Hence the control of vibrations has become a relevant technological challenge. Active vibration control of structures using smart materials especially is in vogue. It involves sensing the motion of the structure using sensors, generating a control signal using a controller and applying a control force on the structure using actuators. To design the control system of any vibrating structure, the mathematical model of the system is required. However, it is not possible, to theoretically construct the model of complex structures. On the other hand, it is relatively simpler to model such systems in an Finite Element (FE) environment like ANSYS©. This paper deals with the extraction of the mathematical model of a cantilever beam from its FEA model. This procedure of extraction is applicable to any mechanical system under dynamics study. Then again, the matrices thus formed are usually very large and require a lot of computational time to process. Hence an attempt is made to construct the reduced model of the system which approximates the actual model to the desired extent. In this paper, the full model of the beam is reduced by discarding those modes which do not contribute to the overall response on the basis of their dc gains in MATLAB©. It is found that the frequency and transient responses of the full and reduced models match closely. Hence the reduced model may be used to represent the system instead of the full model with reasonable accuracy. Design of controller is attempted using the theory of state and output feedback control laws. The controller is modeled by calculating the optimal control gain by formulating an algorithm to solve the equations involved. The transient and frequency responses of the controlled full model and reduced models are then plotted. The procedure for designing controller described in this paper may be extended to any real world system.

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