Vibration suppression of a rotationally periodic structure using an adaptive/PPF control law

2002 ◽  
Author(s):  
Mark J. Keller ◽  
Gregory S. Agnes
Keyword(s):  
Periodic Structure ◽  
Vibration Suppression ◽  
Control Law ◽  
Rotationally Periodic Structure

Excitation of Rotationally Periodic Structures

1979 ◽  
Vol 46 (4) ◽  
pp. 878-882 ◽  
Author(s):  
S. J. Wildheim
Keyword(s):  
Periodic Structure ◽  
Periodic Structures ◽  
Resonance Condition ◽  
Forced Response ◽  
Closed Ring ◽  
Additional Resonance ◽  
Rotationally Symmetric ◽  
Deformation Patterns ◽  
Frequency Diagram ◽  
Rotationally Periodic Structure

A rotationally periodic structure consists of a finite number of identical substructures forming a closed ring. The vibrational behavior of such structures is considered, especially the forced response due to a rotating force. It is known that for a rotationally symmetric structure, excited by a rotating force, resonance for the n nodal diameters mode is obtained when the corresponding natural frequency is ωn = nΩ, where Ω is the angular velocity of the force. This resonance condition also holds for a rotationally periodic structure. But then additional resonance possibilities exist, given by ωn = (kN ± n)Ω, where N is the number of substructures and k = 0, 1, 2,… These resonance conditions give a zigzag line in the nodal diameters versus frequency diagram, which here is introduced as the ZZENF diagram. The deformation patterns at the resonances are both forward and backward traveling waves.

Friction Control for Vibration Suppression

1999 ◽  
Author(s):  
L. Gaul ◽  
R. Nitsche
Keyword(s):  
Normal Force ◽  
Vibration Suppression ◽  
Piezoelectric Element ◽  
Friction Model ◽  
Space Structures ◽  
Control Law ◽  
Large Space ◽  
Normal Contact ◽  
Friction Control ◽  
Frictional Interface

Abstract Friction damping in bolted joint connections of large space structures turned out to be a major source of damping (Gaul and Bohlen, 1987). For vibration suppression, the joints are designed such that the normal force in a frictional interface is controlled which improves damping performance. The use of active control to vary the normal contact force in a joint by means of a piezoelectric element is explored. A model consisting of two elastic beams connected by a single active joint is considered. A friction model with velocity dependent dynamics is used to describe the friction phenomena. A control law for friction dampers which maximizes energy dissipation instantaneously by controlling the normal force at the friction interface is proposed. The effect of displacement- and velocity-induced friction dynamics is considered for the design of the control law. We arrive at a dynamic controller which prevents frictional energy stored as potential energy in a bristle model from being returned to the system.

Active Control of Flexible Riser Vibration by Boundary Control Based on LQR Controller

2019 ◽  
Author(s):  
Jinxin Yu ◽  
Weimin Chen
Keyword(s):  
Boundary Control ◽  
Vibration Suppression ◽  
Lateral Displacement ◽  
Open Loop ◽  
Loop System ◽  
Ocean Current ◽  
Control Law ◽  
Flexible Riser ◽  
Linear Quadratic ◽  
Rotational Angle

Abstract The lateral displacement and the rotational angle of marine riser are likely to get larger as it is in stronger ocean current and, particularly, undergoes the consequences such as vortex-induced vibration or collisions between individual risers. The riser vibration with large amplitude value will lead to fatigue or coating damage of the structural body. In this study, the active vibration control, in terms of its angle and the displacement reductions, of a flexible riser under time-varying distributed load are considered using boundary control. The governing equations of the structural dynamics involving the control system of a flexible riser are built. The riser is modeled as an Euler-Bernoulli beam under the actions of ocean loads and the feedback controller. A torque actuator is introduced at the upper riser boundary, and the control law is employed to generate the required signal for riser angle control and displacement reduction. The feed-back control law is designed in state space, and the optimization of the control law is implemented based on the LQR approach. The linear quadratic regulator is used to determine the gain matrix, which can calculate the boundary control law by solving the Recatti equation. Based on the numerical simulations, the responses of the open-loop system and closed-loop system are presented and compared. The effectiveness of the vibration suppression of the flexible riser is examined.

An active truss element and control law for vibration suppression

1995 ◽  
Vol 4 (4) ◽  
pp. 264-269 ◽  
Author(s):  
J E Bobrow ◽  
F Jabbari ◽  
Kiem Thai
Keyword(s):  
Vibration Suppression ◽  
Control Law ◽  
Truss Element ◽  
And Control

scholarly journals Active Vibration Suppression of Smart Cantilever Beam with Sliding Mode Observer Using Two Piezoelectric Patches

2017 ◽  
Vol 13 (1) ◽  
pp. 50-65
Author(s):  
Shibly A. AL-Samarraie ◽  
Mohsin N. Hamzah ◽  
Imad A. Abdulsahib
Keyword(s):  
Cantilever Beam ◽  
Vibration Suppression ◽  
Sliding Mode ◽  
Control Design ◽  
Sliding Mode Observer ◽  
Reduced Order Model ◽  
Control Law ◽  
Order Model ◽  
Reduced Order ◽  
Tip Displacement

This paper presents a vibration suppression control design of cantilever beam using two piezoelectric ‎patches. One patch was used as ‎an actuator element, while the other was used as a sensor. The controller design was designed via the balance realization reduction method to elect the reduced order model that is most controllable and observable. ‎the sliding mode observer was designed to estimate six states from the reduced order model but three states are only used in the control law. Estimating a number of states larger than that used is in order to increase the estimation accuracy. Moreover, the state ‎estimation error is proved bounded. An ‎optimal LQR controller is designed then using the ‎estimated states with the sliding mode observer, to ‎suppress the vibration of a smart cantilever ‎beam via the piezoelectric elements. The control spillover problem was avoided, by deriving an avoidance ‎condition, to ensure the ‎asymptotic stability for the proposed vibration ‎control design. ‎The numerical simulations were achieved to ‎test the vibration attenuation ability of the ‎proposed optimal control. For 15 mm initial tip ‎displacement, the piezoelectric actuator found ‎able to reduce the tip displacement to about 0.1 ‎mm after 4s, while it was 1.5 mm in the ‎open loop case.  The current experimental results showed a good performance of the proposed LQR control law and the sliding mode observer, as well a good agreement with theoretical results.

Design and performance comparison of interconnection and damping assignment passivity-based control for vibration suppression in active suspension systems

2020 ◽  
pp. 107754632093374
Author(s):  
Pramod Sistla ◽  
Sheron Figarado ◽  
Krishnan Chemmangat ◽  
Narayan Suresh Manjarekar ◽  
Gangadharan Kallu Valappil
Keyword(s):  
Vibration Suppression ◽  
Sliding Mode ◽  
Active Suspension ◽  
Control Law ◽  
Linear Quadratic ◽  
Scaled Model ◽  
Suspension Systems ◽  
Active Suspension Systems ◽  
Special Cases ◽  
Passivity Based Control

This study presents the design of interconnection and damping assignment passivity-based control for active suspension systems. It is well known that interconnection and damping assignment passivity-based control’s design methodology is based on the physical properties of the system where the kinetic and potential energy profiles are shaped, and asymptotic stability is achieved by damping injection. Based on the choice of control variables, special cases of the control law are derived, and tuning of the control law with the physical meaning of the variables is demonstrated along with their simulation results. The proposed control law is experimentally validated on a scaled model of a quarter-car active suspension system with different road profiles, varying load conditions, and noise and delay in the sensor measurements and actuator respectively. The results are compared with that of an uncontrolled system with linear quadratic regulator and sliding mode control.

scholarly journals Semi-Active Pulse-Switching Vibration Suppression Using Sliding Time Window

2013 ◽  
Vol 2013 ◽  
pp. 1-7
Author(s):  
S. Mohammadi ◽  
S. Hatam ◽  
A. Khodayari
Keyword(s):  
Vibration Suppression ◽  
Time Window ◽  
Random Excitation ◽  
Local Extremum ◽  
Control Technique ◽  
Control Law ◽  
Voltage Level ◽  
Switching Sequence ◽  
Pulse Switching ◽  
Random Samples

The performance of pulse-switching vibration control technique is investigated using a new method for switching sequence, in order to enhance the vibration damping. The control law in this method which was developed in the field of piezoelectric damping is based on triggering the inverting switch on each extremum of the produced voltage (or displacement); however, its efficiency in the case of random excitation is arguable because of the local extremum detection process. The new proposed method for switching sequence is only based on the fact that the triggering voltage level was determined using windowed statistical examination of the deflection signal. Results for a cantilever beam excited by different excitation forces, such as stationary and nonstationary random samples, and pulse forces are presented. A significant decrease in vibration energy and also the robustness of this method are demonstrated.

Vibration Suppression of Yarns via Sliding-Mode Control

2011 ◽  
Vol 464 ◽  
pp. 268-271
Author(s):  
Hong Lin ◽  
Zhi Hua Feng ◽  
Xiang Jun Lan
Keyword(s):  
Numerical Simulation ◽  
Finite Difference ◽  
Convergence Rate ◽  
Sliding Mode Control ◽  
Transverse Vibration ◽  
Vibration Suppression ◽  
Sliding Mode ◽  
Control Law ◽  
Mode Control ◽  
Moving Speed

In this paper, a dynamic model of yarn in sizing machines is proposed. The fluxion in moving speed is taken into consideration. By sliding-mode control, the transverse vibration control of the yarns is studied and the control law based on varied tensions is designed. Numerical simulation are carried out using the finite difference approach and results show that the convergence rate of spacing errors of the yarn is fast and the transverse vibration can be well reduced.

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