Reduction of structural weight, costs and complexity of a control system in the active vibration reduction of flexible structures

2014 ◽  
Vol 23 (9) ◽  
pp. 095013 ◽  
Author(s):  
A H Daraji ◽  
J M Hale
Keyword(s):  
Control System ◽  
Vibration Reduction ◽  
Flexible Structures ◽  
Active Vibration

Experiments in Robust Active Vibration Control Design for Slewing Flexible Structures

1999 ◽  
Author(s):  
D. G. Wilson ◽  
G. P. Starr ◽  
G. G. Parker ◽  
R. D. Robinett
Keyword(s):  
Control System ◽  
Vibration Suppression ◽  
Sliding Mode ◽  
Flexible Structures ◽  
Large Angle ◽  
Sensor Data ◽  
Flexible Structure ◽  
Control Effort ◽  
Active Vibration ◽  
Tip Mass

Abstract In this paper we present a hybrid Sliding Mode Control (SMC) and Constant Amplitude Feedback Control (CAFC) architecture for slewing flexible structures. The SMC controller is used to servo the flexible structure and the CAFC is used to suppress residual vibrations of the flexible structure. A single-axis encoder/DC motor/harmonic drive assembly is used for large angle slewing. A graphite/epoxy composite structure with embedded strain sensors/actuators is used for active vibration suppression. The results of this study include the analytical dynamic and control system development with experimental verification. The hybrid control algorithm uses the output sensor data from the encoder and strain sensor along with filters to derive velocity information to compute the control effort for the motor and strain actuators. Near-minimum time maneuvers based on an equivalent rigid structure are used to slew the flexible active structure. The tip mass was varied to evaluate control system robustness. Experimental slewing studies were performed to compare the benefits of using active rather than passive structures. For the active case the experimental results showed a reduction in residual vibration and settling time.

Active vibration control of structures using a leader–follower-based consensus design

2016 ◽  
Vol 24 (1) ◽  
pp. 60-72 ◽  
Author(s):  
Ehsan Omidi ◽  
S Nima Mahmoodi
Keyword(s):  
Control System ◽  
Vibration Control ◽  
Active Vibration Control ◽  
Flexible Structures ◽  
Distributed Parameter ◽  
Arbitrary Form ◽  
Piezoelectric Layers ◽  
Active Vibration ◽  
System States ◽  
Virtual Leader

This paper proposes a new leader–follower-based consensus vibration controller to actively suppress unwanted oscillations in distributed-parameter flexible structures. Actuation and sensing is performed via piezoelectric layers in a collocated sense. The actuator/sensor patches for the vibration control system are considered to collaborate in a network, and follow a virtual leader which is accessible to all agents. Hence, a vibration controller law is defined, to remove disagreement between agents and force the agents to follow the virtual leader. The proposed approach is an observer-based design, in which an optimal consensus state estimator is initially designed. Stability of the closed-loop system is investigated and the optimality conditions of the system are derived. Although the designed vibration controller could be implemented for suppression tasks in different distributed-parameter systems, a flexible clamped-clamped beam is used here for equation derivation and numerical performance verification. According to the results, the optimal observer estimates the system states in a finite time, as expected, and the vibration controller suppresses unwanted oscillations, either in resonant or arbitrary form, to a much lower level; while the disagreement between agents converges to zero. Additionally, suppression performance and robustness of the controller to failure in control system elements is investigated in comparison with a conventional positive position feedback controller, and its superiority is illustrated and discussed.

Analysis of Active Vibration Reduction for Soft Mounted Electrical Machines Based on a Multibody Model

2016 ◽  
Vol 08 (08) ◽  
pp. 1650085 ◽  
Author(s):  
Ulrich Werner
Keyword(s):  
Control System ◽  
Feedback Control ◽  
Active Vibration Control ◽  
Vibration Reduction ◽  
Electrical Machines ◽  
Feedback Control System ◽  
Multibody Model ◽  
Soft Foundation ◽  
Vibration Model ◽  
Active Vibration

The aim of the paper is to analyze active vibration reduction of soft mounted electrical machines by using actuators between the motor feet and a soft foundation based on a multibody model. The actuator forces are inserted directly in the vibration model without using a feedback control system. The goal is to reduce the forced vibrations, which are caused by typical excitations of electrical motors — eccentricity of rotor mass, bent rotor deflection and magnetic eccentricity. Based on the simplified model, the mathematical coherences are derived and a numerical example is shown, where different vibration reduction concepts are analyzed and the necessary actuator forces are calculated. The aim of the paper is to show the capability of using actuators between motor feet and soft foundation, based on a simplified multibody vibration model. For future work, the multibody model has to be implemented into a feedback control system for active vibration control.

Experiment Verification of Seismic Isolation Device Having Charging Function

2017 ◽  
Author(s):  
Takashi Yamaguchi ◽  
Hayato Nakakoji ◽  
Nanako Miura ◽  
Akira Sone
Keyword(s):  
Control System ◽  
Vibration Control ◽  
Control Systems ◽  
Seismic Isolation ◽  
Active Vibration Control ◽  
Vibration Reduction ◽  
Large Earthquake ◽  
Energy Regeneration ◽  
Active Vibration ◽  
Isolation Device

In late years, many base isolated structures are planned as seismic design, because they suppress vibration response significantly against large earthquake. In addition, to achieve greater safety, semi-active or active vibration control system is installed in the structures as. Semi-active and active vibration control systems are more effective to large earthquake than passive one vibration control system in terms of vibration reduction. However semi-active and active vibration control systems cannot operate as required when external power supply is cut off. To solve the problem of energy consumption, we propose a self-powered active seismic isolation device which achieves active control system using regenerated vibration energy. This device doesn’t require external energy to produce control force. The purpose of this paper is to propose the seismic isolation device having charging function and verified its performance by experiment. In our previous research[1], we proposed the new model and optimized the control system and passive elements such as spring coefficients and damping coefficients using genetic algorithm. As a result, we proposed the model which is superior to the previous model in terms of vibration reduction and energy regeneration. In this study, we conducted an experiment and show its results. As a results, we confirmed the vibration reduction and energy regeneration of the seismic isolation device having charging function.

New Methodology for Optimal Placement of Piezoelectric Sensor/Actuator Pairs for Active Vibration Control of Flexible Structures

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Ali H. Daraji ◽  
Jack M. Hale ◽  
Jianqiao Ye
Keyword(s):  
Vibration Reduction ◽  
Flexible Structures ◽  
Optimal Solution ◽  
Computational Effort ◽  
Optimization Techniques ◽  
Optimal Placement ◽  
Simplified Approach ◽  
Average Percentage ◽  
Sensor Actuator ◽  
Active Vibration

This paper describes a computationally efficient method to determine optimal locations of sensor/actuator (s/a) pairs for active vibration reduction of a flexible structure. Previous studies have tackled this problem using heuristic optimization techniques achieved with numerous combinations of s/a locations and converging on a suboptimal or optimal solution after multithousands of generations. This is computationally expensive and directly proportional to the number of sensors, actuators, possible locations on structures, and the number of modes required to be suppressed (control variables). The current work takes a simplified approach of modeling a structure with sensors at all locations, subjecting it to external excitation force or structure base excitation in various modes of interest and noting the locations of n sensors giving the largest average percentage sensor effectiveness. The percentage sensor effectiveness is measured by dividing all sensor output voltage over the maximum for each mode using time and frequency domain analysis. The methodology was implemented for dynamically symmetric and asymmetric structures under external force and structure base excitations to find the optimal distribution based on time and frequency responses analysis. It was found that the optimized sensor locations agreed well with the published results for a cantilever plate, while with very much reduced computational effort and higher effectiveness. Furthermore, it was found that collocated s/a pairs placed in these locations offered very effective active vibration reduction for the structure considered.

scholarly journals Classes of Strongly Stabilizing Bandpass Controllers for Flexible Structures

2012 ◽  
Vol 2012 ◽  
pp. 1-11
Author(s):  
Alberto Cavallo ◽  
Giuseppe De Maria ◽  
Ciro Natale ◽  
Salvatore Pirozzi
Keyword(s):  
Control Strategies ◽  
Vibration Reduction ◽  
Flexible Structures ◽  
Linear Matrix ◽  
Design Strategies ◽  
Control Laws ◽  
Practical Applications ◽  
Strong Stabilization ◽  
Inequality Technique ◽  
Active Vibration

This paper proposes different design strategies of robust controllers for high-order plants. The design is tailored on the structure of the equations resulting from modeling flexible structures by using modal coordinates. Moreover, the control laws have some characteristics which make them specially suited for active vibration reduction, such as strong stabilization property and bandpass frequency shape. The approach is also targeted the case of more sensors than actuators, which is very frequent in practical applications. Indeed, actuators are often rather heavy and bulky, while small and light sensors may be placed more freely. In such cases, sensors can be usefully placed in the locations where the primary force fields act on the structure, so as to provide the controller with a direct information on the disturbance effects in terms of structural vibrations. Eventually, this approach may lead to uncolocated control strategies. The design problem is here solved by resorting to a Linear Matrix Inequality technique, which allows also to select the performance weights based on different design requirements, for example, a suitable bandpass frequency shape. Experimental results are presented for a vibration reduction problem of a stiffened aeronautical panel controlled by piezoelectric actuators.

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