Robust Active Vibration Control of a Bandsaw Blade

1999 ◽  
Vol 122 (1) ◽  
pp. 69-76 ◽  
Author(s):  
Christopher J. Damaren ◽  
Lan Le-Ngoc
Keyword(s):  
Analytical Study ◽  
Active Vibration Control ◽  
State Space Model ◽  
Time Varying ◽  
Axial Motion ◽  
Exogenous Disturbances ◽  
Active Vibration ◽  
And Performance ◽  
Rate Sensor ◽  
Gyroscopic Effects

An analytical study of a vibrating bandsaw blade is presented. The blade is modeled as a plate translating over simply-supporting guides. Gyroscopic effects due to the blade’s axial motion as well as in-plane forces resulting from tensioning and the influence of the cutting force are included in the model. The latter is modeled as a nonconservative follower force on the cutting edge of the blade and shown to be destabilizing. A state-space model is developed which includes the effects of time-varying cutting forces and exogenous disturbances. Feedback control via a collocated force actuator/rate sensor is introduced and recent advances in robust control theory are used develop controllers which achieve robust stability and performance with respect to the time-varying model. [S0739-3717(00)01101-6]

Gain-Scheduled ℋ∞-Control for Active Vibration Isolation of a Gyroscopic Rotor

2015 ◽  
Author(s):  
Fabian B. Becker ◽  
Martin A. Sehr ◽  
Stephan Rinderknecht
Keyword(s):  
Degrees Of Freedom ◽  
Vibration Isolation ◽  
Linear Time ◽  
Displacement Sensors ◽  
Active Vibration ◽  
And Performance ◽  
Gyroscopic Effects ◽  
Gain Scheduled ◽  
Active Vibration Isolation

This paper deals with active vibration isolation of unbalance-induced oscillations in rotors using gain-scheduled H∞-controller via active bearings. Rotating machines are often exposed to gyroscopic effects, which occur due to bending deformations of rotors and the consequent tilting of rotor disks. The underlying gyroscopic moments are proportional to the rotational speed and couple the rotor’s radial degrees of freedom. Accordingly, linear time-varying models are well suited to describe the system dynamics in dependence on changing rotational speeds. In this paper, we design gain-scheduled H∞-controllers guaranteeing both robust stability and performance within a predefined range of operating speeds. The paper is based on a rotor test rig with two unbalance-induced resonances in its operating range. The rotor has two discs and is supported by one active and one passive bearing. The active support consists of two piezoelectric stack actuators and two collocated piezoelectric load washers. In addition, the rig is equipped with four inductive displacement sensors located at the discs. Closed-loop performance is assessed via isolation of unbalance-induced vibrations using both simulation and experimental data. This contribution is the next step on our path to achieving the long-term objective of combined vibration attenuation and isolation.

Robust Kalman-Filter-Based Frequency-Shaping Optimal Active Vibration Control of Uncertain Flexible Mechanical Systems with Nonlinear Actuators

2003 ◽  
Vol 9 (6) ◽  
pp. 623-644 ◽  
Author(s):  
Shinn-Horng Chen
Keyword(s):  
Vibration Control ◽  
Active Vibration Control ◽  
Time Varying ◽  
Time Varying Parameter ◽  
Robust Kalman Filter ◽  
Parameter Perturbations ◽  
Actuator Nonlinearities ◽  
Active Vibration ◽  
Control Methodology ◽  
Flexible Mechanical System

In this paper, we present a time-domain control methodology, called the robust Kalman-filter-based frequency-shaping optimal feedback (KFBFSOF) control method. Using this method, we treat the active vibration control (or active vibration suppression) problem of flexible mechanical systems under simultaneously high-frequency unmodeled dynamics, residual modes, linear time-varying parameter perturbations in both the controlled and residual parts, noises (input noise and measurement noise), noise uncertainties and actuator nonlinearities. Two robust stability conditions are proposed for the flexible mechanical system, which is controlled by a KFBFSOF controller and subject to mode truncation, noise uncertainties, actuator nonlinearities and linear structured time-varying parameter perturbations simultaneously. The advantage of the presented KFBFSOF control methodology is that it can make the controlled closed-loop system have both good robustness at high frequencies and good performance at low frequencies. Besides, the proposed robust stability criteria guarantee that the designed KFBFSOF controller can make the controlled flexible mechanical system avoid the possibilities of instability induced by both spillover and time-varying parameter perturbations. Two examples are given to illustrate the application of the presented control methodology to the active vibration control problems of a simply-supported flexible beam and of a flexible rotor system.

scholarly journals Semi-active vibration control of high-speed rotor system with electrorheological bearing fluid

2018 ◽  
Vol 211 ◽  
pp. 14008
Author(s):  
Rajasekhara Reddy Mutra ◽  
J Srinivas
Keyword(s):  
Electric Field ◽  
External Electric Field ◽  
High Speed ◽  
Active Vibration Control ◽  
Electrorheological Fluid ◽  
Carrier Fluid ◽  
Active Particles ◽  
Active Vibration ◽  
Gyroscopic Effects

Present work focuses on the use of electrorheological fluid (ERF) as a lubricant in the high speed turbocharger rotor supported on floating ring bearings. The rotor is analysed by finite element modelling with gyroscopic effects and bearing forces. The ERF contains one carrier fluid and active particles that react to external electric field, which induces a yield stress in the fluid increasing its viscosity. In order to control the rotor vibration amplitudes, the dynamic changes in the fluid viscosities at the inner and outer films of bearing are employed with external electric field. A case study of automotive turbocharger rotor is considered and the effect of semi-active control is illustrated on the dynamic response of the system.

scholarly journals Adaptive Feedforward Compensating Self-Sensing Method for Active Flutter Suppression

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3447 ◽  
Author(s):  
Yizhe Wang ◽  
Zhiwei Xu
Keyword(s):  
Vibration Control ◽  
Bridge Circuit ◽  
Active Vibration Control ◽  
Local Strain ◽  
The Self ◽  
Negative Effects ◽  
Active Vibration ◽  
And Performance ◽  
The Time Domain ◽  
Application Fields

A single piezoelectric patch can be used as both a sensor and an actuator by means of the self-sensing piezoelectric actuator, and the function of self-sensing shows several advantages in many application fields. However, some problems exist in practical application. First, a capacitance bridge circuit is set up to realize the function of self-sensing, but the precise matching of the capacitance of the bridge circuit is hard to obtain due to the standardization of electric components and variations of environmental conditions. Second, a local strain is induced by the self-sensing actuator that is not related to the global vibration of the structure, which would affect the performance of applications, especially in active vibration control. The above problems can be tackled by the feedforward compensation method that is proposed in this paper. A configured piezoelectric self-sensing circuit is improved by a feedforward compensation tunnel, and a gain of compensation voltage is adjusted by the time domain and frequency domain’s steepest descent algorithms to alleviate the capacitance mismatching and local strain problems. The effectiveness of the method is verified in the experiment of the active vibration control in a wind tunnel, and the control performance of compensated self-sensing actuation is compared to the performance with capacitance mismatching and local strain. It is found that the above problems have negative effects on the stability and performance of the vibration control and can be significantly eliminated by the proposed method.

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