Time-Optimal Negative Input Shapers

1997 ◽  
Vol 119 (2) ◽  
pp. 198-205 ◽  
Author(s):  
W. E. Singhose ◽  
W. P. Seering ◽  
Neil C. Singer
Keyword(s):  
Rise Time ◽  
The Other ◽  
High Mode ◽  
Piezo Actuator ◽  
Input Shaping ◽  
Residual Vibration ◽  
Dc Motors ◽  
Mode Excitation ◽  
Time Optimal ◽  
Computer Controlled

Input shaping reduces residual vibration in computer controlled machines by convolving a sequence of impulses with a desired system command. The resulting shaped input is then used to drive the system. The impulse sequence has traditionally contained only positively valued impulses. However, when the impulses are allowed to have negative amplitudes, the rise time can be improved. Unfortunately, excitation of unmodeled high modes and overcurrenting of the actuators may accompany the improved rise time. Solutions to the problem of high-mode excitation and overcurrenting are presented. Furthermore, a simple look-up method is presented that facilitates the design of negative input shapers. The performance of negative shapers is evaluated experimentally on two systems; one driven by a piezo actuator and the other equipped with DC motors.

Robust Negative Input Shapers for Vibration Suppression

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Joshua Vaughan ◽  
Aika Yano ◽  
William Singhose
Keyword(s):  
Rise Time ◽  
Vibration Suppression ◽  
Control Method ◽  
High Mode ◽  
Input Shaping ◽  
Bridge Crane ◽  
Modeling Errors ◽  
Parameter Variations ◽  
Mode Excitation ◽  
Theoretical Predictions

Input shaping is a control method that limits motion-induced oscillation in vibratory systems by intelligently shaping the reference command. As with any control method, the robustness of input shaping to parameter variations and modeling errors is an important consideration. For input shaping, there exists a fundamental compromise between robustness to such errors and system rise time. For all types of shapers, greater robustness requires a longer duration shaper, which degrades rise time. However, if a shaper is allowed to contain negative impulses, then the shaper duration may be shortened with only a small cost of robustness and possible high-mode excitation. This paper presents a thorough analysis of the compromise between shaper duration, robustness, and possible high-mode excitation for several negative input-shaping methods. In addition, a formulation for specified negative amplitude, specified insensitivity shapers is presented. These shapers provide a continuous spectrum of solutions for the duration/robustness/high-mode excitation trade-off. Experimental results from a portable bridge crane verify the theoretical predictions.

Comparison of Polynomial Cam Profiles and Input Shaping for Driving Flexible Systems

2012 ◽  
Vol 134 (12) ◽  
Author(s):  
Brice Pridgen ◽  
William Singhose
Keyword(s):  
Rise Time ◽  
Laplace Transforms ◽  
Experimental Results ◽  
Input Shaping ◽  
Flexible Systems ◽  
Residual Vibration ◽  
Alternative Method ◽  
Cam Follower ◽  
Low Pass ◽  
Polynomial Profiles

Polynomial profiles can be used as reference commands to limit induced vibration in flexible systems. Due to their ease of design and low-pass filtering effects, polynomial profiles are often found in cam-follower systems. Polynomial profiles have also been used as smooth reference commands for automated machines. However, despite extensive work to develop and improve such profiles, inherent tradeoffs still exist between induced vibration, rise time, and ease of design. Input shaping is an alternative method for generating motion commands that reduce residual vibration. This paper compares polynomial profiles to input-shaped commands for the application of reducing vibration in flexible systems. Analyses using Laplace transforms reveal that input shapers suppress vibration at regularly spaced frequencies. However, polynomial profiles do not share this property. Simulations and experimental results show that input shaping improves rise time and reduces residual vibration in comparison to polynomial profiles.

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.

Computer-Controlled Hrem Alignment Using Automated Diffractogram Analysis

1990 ◽  
Vol 48 (1) ◽  
pp. 532-533
Author(s):  
G.Y. Fan ◽  
O.L. Krivanek
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
The Other ◽  
Full Information ◽  
Resolution Electron ◽  
Skilled Operator ◽  
Automatic Alignment ◽  
High Resolution Electron Microscope ◽  
Computer Controlled ◽  
Recorded Image

Full alignment of a high resolution electron microscope (HREM) requires five parameters to be optimized: the illumination angle (beam tilt) x and y, defocus, and astigmatism magnitude and orientation. Because neither voltage nor current centering lead to the correct illumination angle, all the adjustments must be done on the basis of observing contrast changes in a recorded image. The full alignment can be carried out by a computer which is connected to a suitable image pick-up device and is able to control the microscope, sometimes with greater precision and speed than even a skilled operator can achieve. Two approaches to computer-controlled (automatic) alignment have been investigated. The first is based on measuring the dependence of the overall contrast in the image of a thin amorphous specimen on the relevant parameters, the other on measuring the image shift. Here we report on our progress in developing a new method, which makes use of the full information contained in a computed diffractogram.

Expressive Microstructure in Music: A Preliminary Perceptual Assessment of Four Composers' "Pulses"

1989 ◽  
Vol 6 (3) ◽  
pp. 243-273 ◽  
Author(s):  
Bruno H. Repp
Keyword(s):  
Classical Music ◽  
Random Order ◽  
Preliminary Test ◽  
The Other ◽  
Musical Experience ◽  
General Music ◽  
Cyclic Patterns ◽  
Computer Controlled ◽  
Perceptual Assessment ◽  
Essential Prerequisite

According to a provocative theory set forth by Manfred Clynes, there are composer-specific cyclic patterns of (unnotated) musical microstructure that, when discovered and realized by a performer, help to give the music its characteristic expressive quality. Clynes, relying mainly on his own judgment as an experienced musician, has derived such personal "pulses" for several famous composers by imposing time and amplitude perturbations on computer-controlled performances of classical music and modifying them until they converged on some optimal expression. To conduct a preliminary test of the general music lover's appreciation of such "pulsed" performances, two sets of piano pieces by Beethoven, Haydn, Mozart, and Schubert, one in quadruple and the other in triple meter, were selected for this study. Each piece was synthesized with each composer's pulse and also without any pulse. These different versions were presented in random order to listeners of varying musical sophistication for preference judgments relative to the unpulsed version. There were reliable changes in listeners' pulse preferences across different composers' pieces, which affirms one essential prerequisite of Clynes' theory. Moreover, in several instances the "correct" pulse was preferred most, which suggests not only that these pulse patterns indeed capture composer- specific qualities, but also that listeners without extensive musical experience can appreciate them. In other cases, however, listeners' preferences were not as expected, and possible causes for these deviations are discussed.

Effect of Input Shaping on Response of Inertia Plants

2011 ◽  
Vol 121-126 ◽  
pp. 2676-2680
Author(s):  
Ming Xiao Dong ◽  
Rui Chuan Li ◽  
Qin Zu Xu
Keyword(s):  
Control System ◽  
Feedback Control ◽  
Control Systems ◽  
Setting Time ◽  
Input Shaping ◽  
Pd Controller ◽  
Residual Vibration ◽  
Simulation Results ◽  
Analytical Expressions ◽  
Input Shaping Control

A poorly designed control system can lead to excessive residual vibration and long setting time. This paper investigates the effect of input shaping on control efficiency. To perform this investigation, we design a PD controller combined with input shaping for an inertia plant. We then subject it to four standard types of inputs. The responses of the control systems are described by analytical expressions. The performances of PD control and PD combined with input-shaping control are thoroughly analyzed and compared. Simulation results show that PD feedback control enhanced with input shaping minimizes overshoot and setting time.

scholarly journals INPUT SHAPING CONTROL TO REDUCE RESIDUAL VIBRATION OF A FLEXIBLE BEAM

2016 ◽  
Vol 32 (1) ◽  
pp. 75-90 ◽  
Author(s):  
Quoc Chi Nguyen ◽  
Ha Quang Thinh Ngo
Keyword(s):  
Control Algorithms ◽  
Input Shaping ◽  
Flexible Beam ◽  
Residual Vibration ◽  
Motion System ◽  
Damped System ◽  
Input Shaping Control

In this paper, three control algorithms based on input shaping method are developed to suppress the residual vibration of a flexible beam. The flexible beam is modeled as an under-damped system. Three input shapers, ZV, ZVD, and ZVDD, are used to control the flexible beam. The three control algorithms are implemented by using the Mechatrolink-III motion system. The experiments are performed to verify the effectiveness of the three control algorithms.

Input Shaping for Flexible System With Nonlinear Spring and Damper

2017 ◽  
Author(s):  
Withit Chatlatanagulchai ◽  
Ittidej Moonmangmee ◽  
Pisit Intarawirat
Keyword(s):  
Linear System ◽  
Input Shaping ◽  
Destructive Interference ◽  
Impulse Responses ◽  
Residual Vibration ◽  
Energy Principle ◽  
Nonlinear Spring ◽  
Flexible System ◽  
Input Shaper ◽  
Simulation And Experiment

Input shaping suppresses residual vibration by destructive interference of the impulse responses. Because proper destructive interference requires superposition property of the linear system, traditional input shaper only applies to the linear flexible system. In this paper, the work and energy principle is used to derive input shaper for flexible system having nonlinear spring and damper. It was shown via simulation and experiment that this type of shaper performs well with nonlinear systems. Positive, robust, and negative input shapers are discussed.

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