scholarly journals Vibration Reduction of Axially-extending Cantilever Beams under Gravity Using Command Shaping

2016 ◽  
Vol 12 (12) ◽  
pp. 1196-1203
Author(s):  
Seong-Wook Hong ◽  
Seon-Woong Kwon ◽  
William E. Singhose
Keyword(s):  
Vibration Reduction ◽  
Cantilever Beams ◽  
Command Shaping

Friction-Compensating Command Shaping for Vibration Reduction

2004 ◽  
Vol 127 (4) ◽  
pp. 307-314 ◽  
Author(s):  
Jason Lawrence ◽  
William Singhose ◽  
Keith Hekman
Keyword(s):  
Steady State ◽  
Coulomb Friction ◽  
Vibration Reduction ◽  
Input Shaping ◽  
Residual Vibration ◽  
Command Shaping ◽  
Point Motion ◽  
Common Operation ◽  
Point To Point ◽  
Theoretical Developments

Fast and accurate point-to-point motion is a common operation for industrial machines, but vibration will frequently corrupt such motion. This paper develops commands that can move machines without vibration, even in the presence of Coulomb friction. Previous studies have shown that input shaping can be used on linear systems to produce point-to-point motion with no residual vibration. This paper extends command-shaping theory to nonlinear systems, specifically systems with Coulomb friction. This idea is applied to a PD-controlled mass with Coulomb friction to ground. The theoretical developments are experimentally verified on a solder cell machine. The results show that the new commands allow the proportional gain to be increased, resulting in reduced rise time, settling time, and steady-state error.

scholarly journals Adaptive Damping of a Double-Beam Structure Based on Magnetorheological Elastomer

2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Tomasz Szmidt ◽  
Dominik Pisarski ◽  
Robert Konowrocki ◽  
Stefan Awietjan ◽  
Anna Boczkowska
Keyword(s):  
Mathematical Modeling ◽  
Magnetic Field ◽  
Vibration Reduction ◽  
Free Vibrations ◽  
Semiactive Control ◽  
Cantilever Beams ◽  
Magnetorheological Elastomer ◽  
Beam Structure ◽  
Magnetorheological Elastomers ◽  
Double Beam

A method of vibration reduction based on activation of an MRE block that couples twin cantilever beams at their free ends is investigated. Four types of magnetorheological elastomers have been manufactured, and their rheological properties in a range of magnetic field intensities are established. Free vibrations of several double-beam structures with controllable damping members made of these MREs are investigated, and a method of semiactive control of such structures is proposed. The effects of compression of the elastomers and alignment of the magnets used to activate them are reported. The mathematical modeling of the system is verified experimentally.

Reference Command Shaping Using Specified-Negative-Amplitude Input Shapers for Vibration Reduction

2004 ◽  
Vol 126 (1) ◽  
pp. 210-214 ◽  
Author(s):  
William Singhose ◽  
Erika Ooten Biediger ◽  
Ye-Hwa Chen ◽  
Bart Mills
Keyword(s):  
Rise Time ◽  
Vibration Reduction ◽  
Input Shaping ◽  
Case Scenario ◽  
Worst Case ◽  
Performance Gap ◽  
Command Shaping ◽  
Mode Excitation ◽  
New Type ◽  
Command Signals

Residual vibrations can be greatly reduced by using specially-shaped reference command signals. Input shaping is one such technique that reduces vibration by convolving a sequence of impulses with any desired reference command. Several types of useful impulse sequences have been developed. Most of these have contained only positively valued impulses. However, rise time can be improved by using some negative impulses in the sequence. Unfortunately, the use of negative impulses can excite unmodeled high modes. A new type of impulse sequence containing negative impulses is proposed. These sequences are designed to fill the performance gap between all-positive impulse sequences and the negative sequences previously developed. A proof governing the worst case scenario provides an upper bound on high-mode excitation. The resulting class of impulse sequences allows the designer to make a precise trade off between rise time and vibration reduction.

On the Use of Robust Command Shaping for Vibration Reduction During Remote Handling of Large Components in Tokamak Devices

2018 ◽  
Author(s):  
Stanislao Grazioso ◽  
Giuseppe Di Gironimo
Keyword(s):  
Power Reactor ◽  
Control Strategies ◽  
Vibration Reduction ◽  
Fusion Reactors ◽  
Dynamic Simulations ◽  
Command Shaping ◽  
Main Motivation ◽  
Remote Handling ◽  
Reference Motion ◽  
Control Framework

This paper proposes to use robust command shaping methods for reducing the vibrations during remote handling of in-vessel components. The need of deriving efficient vibration control strategies for a safe transportation of large and heavy pay-loads during maintenance procedures in nuclear fusion reactors is the main motivation behind this work. The approach shapes the reference motion command to the component such that the vibratory modes of the system are canceled. We perform the dynamic simulations of a large in-vessel component of the DEMOnstrating fusion power reactor during a remote handling operation. The simulations shows that the method is a possible solution to reduce the vibrations induced by the motion, in both the transient and residual phases. The benefits introduced by command shaping make the method promising towards building control framework for remote handling of in-vessel components in various tokamak devices.

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