Experimental demonstration of input preconditioning for residual vibration suppression using low-pass FIR digital filters

2001 ◽  
Author(s):  
D. Economou ◽  
C. Lee ◽  
C. Mavroidis ◽  
I. Antoniadis
Keyword(s):  
Digital Filters ◽  
Vibration Suppression ◽  
Experimental Demonstration ◽  
Residual Vibration ◽  
Low Pass ◽  
Fir Digital Filters ◽  
Residual Vibration Suppression

Maximally Robust Input Preconditioning for Residual Vibration Suppression Using Low-Pass FIR Digital Filters

2000 ◽  
Vol 124 (1) ◽  
pp. 85-97 ◽  
Author(s):  
D. Economou ◽  
C. Mavroidis ◽  
I. Antoniadis ◽  
C. Lee
Keyword(s):  
Digital Filters ◽  
Vibration Suppression ◽  
Least Squares Method ◽  
Finite Impulse Response ◽  
Stop Band ◽  
Cutoff Frequency ◽  
Fir Filters ◽  
Flexible System ◽  
Low Pass ◽  
Fir Digital Filters

A method for suppressing residual vibrations in flexible systems is presented and experimentally demonstrated. The proposed method is based on the preconditioning of the inputs to the system using low-pass Finite Impulse Response (FIR) digital filters. Provided that the cutoff frequency of FIR filters is selected lower than the lowest expected natural frequency of the system and their stop-band is maximized, we show that these filters can be designed to exhibit maximally robust behavior with respect to changes of the system natural frequencies. To perform the proper design of FIR filters for robust vibration suppression, this paper introduces a series of dimensionless performance indexes and the Delay-Error-Order (DEO) curves that represent graphically the delay time introduced by the filter as a function of the remaining residual vibrations, and the filter order. Several classes of FIR filters such as: a) Parks-McClellan; b) Window-based methods (using Chebyshev window); and c) Constrained Least Squares method, are shown to present maximally robust behavior, almost identical to the theoretically predicted. Parallel, they demonstrate excellent vibration suppression while they introduce the minimum possible delay. Further advantages offered by the proposed method, is that no modeling of the flexible system is required, the method can be used in a variety of systems exhibiting vibrations, it is independent of the guidance function and it is simple to implement in practical applications. The results are experimentally verified on a flexible aluminum beam with a significantly varying mass, attached to the end-effector of a robot manipulator. The beam is rotated, using one joint of the manipulator, from an initial to a final position. It is shown that the preconditioned inputs to the flexible system induce very little amount of residual vibrations compared to the inputs with no preconditioning.

Comparison of Robust Residual Vibration Suppression Capabilities of Conventional Digital Filters

2001 ◽  
Author(s):  
D. Economou ◽  
C. Mavroidis ◽  
I. Antoniadis
Keyword(s):  
Digital Filters ◽  
Vibration Suppression ◽  
Design Procedure ◽  
Single Type ◽  
Design Parameters ◽  
Residual Vibration ◽  
Total Delay ◽  
Flexible System ◽  
Different Characteristics ◽  
Residual Vibration Suppression

Abstract Digital filters consist a quite effective robust residual vibration tool, when they are used for preconditioning any excitation function, prior to its application in a flexible system. Since a quite large number of conventional digital filters already exist, each one obtained by a different design procedure and resulting to different characteristics, a systematic comparison of their capabilities is performed. Critical design parameters are addressed, influencing the filter behavior in vibration suppression, such as the total delay introduced by the filter, the permitted residual vibration error, the robustness degree achieved and the necessary computational requirements in their implementation. It is shown, that although mere does not exist a single type of filter, simultaneously conforming to an optimal degree to all the design requirements, a large variety of conventional filters can be effectively used for the several individual residual vibration suppression requirements.

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