Design of Vibration Absorbers for Step Motions and Step Disturbances

Abstract

Mechanical systems with flexible dynamics often suffer from vibration induced by changes in the reference command or from external disturbances. The technique of adding a vibration absorber has proven useful at eliminating vibrations from external disturbances and rotational imbalances. Traditionally, vibration absorbers have been designed for systems subject to sinusoidal or random excitations. Here the applicability of vibration absorbers to systems with steplike changes in the reference command or similar disturbances is studied. This type of motion is more common in robotic applications. Here absorbers are designed using two methods; the first technique uses a weighting on peak overshoot and settling time to allow tradeoffs between the two performance criteria. The second simpler method utilizes an eigenvalue technique to predict the time constant. Both of these techniques provide the possibility of significant improvement in settling time. The performance of this absorber design strategies is compared with previously proposed vibration absorbers and experimental results verify its utility.

Tuned mass dampers for flight vehicle components subjected to rocket noise

“…Descent sub-gradient method to maximize the minimal damping of modes in a prescribed frequency range for general viscous or hysteretic multi-degree-of-freedom tuned mass systems is reported in [11]. Vibration absorbers to systems with step like changes in disturbances have been reported in [4]. Li and Zhu [7] have studied double TMDs consisting of one larger mass block and one smaller mass block to evolve mass dampers with high effectiveness and robustness for the reduction of undesirable vibrations.…”

Optimal design of vibration absorber using minimax criterion with simplified constraints

“…On the other hand, some of the variables have no obvious physical meaning, the initials of which are hard to be chosen, such as L and Δ (see also Ref. [6], etc.). Therefore, in this investigation, a modified minimax design of damped dynamic vibration absorber for a damped primary system is presented.…”

“…A damped vibration absorber consists of a damper and a spring which are added to the primary mass on one side and attached to the absorber mass on the other side. Since Watts and Frahm [1,2] reported on the first [3][4][5][6][7] and tuning of the vibration absorber [8][9][10][11][12].…”

Optimal apparent damping as a function of the bandwidth of an array of vibration absorbers

“…7 Much of this literature addresses either the response to low single frequency excitations produced by machinery 8 or ocean waves, or the response to time-extended random inputs such as wind or seismic disturbances. 9 There is a limited body of literature concerning the use of DVAs to alter transient response 10 generally and step response [11][12][13][14] specifically.…”