Vibration Reduction Using Multi-Hump Input Shapers

1997 ◽  
Vol 119 (2) ◽  
pp. 320-326 ◽  
Author(s):  
W. E. Singhose ◽  
L. J. Porter ◽  
T. D. Tuttle ◽  
N. C. Singer
Keyword(s):  
Parameter Uncertainty ◽  
Control Experiment ◽  
Space Shuttle ◽  
Vibration Reduction ◽  
Input Shaping ◽  
Input Shaper ◽  
Shaping Process ◽  
Modeling Errors ◽  
System Input ◽  
Computer Controlled

Input shaping is a method for reducing residual vibrations in computer-controlled machines. Vibration is eliminated by convolving an input shaper, which is a sequence of impulses, with a desired system command to produce a shaped input. The shaped input then becomes the command to the system. Requiring the vibration reduction to be robust to modeling errors and system nonlinearities is critical to the success of the shaping process on any real system, Input shapers can be made very insensitive to parameter uncertainty; however, increasing robustness usually increases system delays. A design process is presented that generates input shapers with insensitivity-to-time-delay ratios that are much larger than traditionally designed input shapers. The advantages of the new shapers are demonstrated with computer simulations and their performance is verified with experimental results from the MIT Middeck Active Control Experiment, which was performed on board the Space Shuttle Endeavor.

A Simple Procedure for Modifying High-Speed Cam Profiles for Vibration Reduction

2004 ◽  
Vol 126 (6) ◽  
pp. 1105-1108 ◽  
Author(s):  
Ulf Andresen ◽  
William Singhose
Keyword(s):  
Real Time ◽  
High Speed ◽  
Simple Procedure ◽  
Vibration Reduction ◽  
Operating Costs ◽  
Input Shaping ◽  
Cam Design ◽  
Experimental Apparatus ◽  
Cam Follower ◽  
Computer Controlled

Unwanted vibration in cam-follower systems causes increased forces, noise, wear, and operating costs. This paper investigates the use of input shaping on cam profiles to reduce vibration. Input shaping is a real-time command modification algorithm developed for computer-controlled machines. In order to apply the concept to cam design, some modifications to the algorithm must be made. To test the validity of high-speed input-shaped cam profiles, an experimental apparatus was constructed with variable operating speeds and follower dynamics. The experimental results demonstrate the effectiveness of the proposed solution.

Parametrization of all Three Impulse Zero Vibration Input Shapers

2010 ◽  
Vol 164 ◽  
pp. 271-277
Author(s):  
Miloš Schlegel ◽  
Lukáš Bláha
Keyword(s):  
Vibration Reduction ◽  
Input Shaping ◽  
Simple Method ◽  
Input Shaper ◽  
Command Signal

Input shaping has been demonstrated to be a simple method of reducing vibration in many types of controlled machines. The method is implemented by convolving a command signal with an impulse sequence of input shaper to produce a shaped input that is then used to command the system. Designing the input shaper involves determining the amplitudes and timing of the impulses such that the resulting shaped commands lead to desired levels of vibration reduction. Up to now, to the best knowledge of the authors, it is known only few special types of input shapers (ZV, ZVD, ZVDk, EI, SI,...). This paper presents two general approaches for parametrization of all three impulse zero vibration input shapers.

Robust Input Shaper Control Design for Parameter Variations in Flexible Structures

1999 ◽  
Vol 122 (1) ◽  
pp. 63-70 ◽  
Author(s):  
Lucy Y. Pao ◽  
Mark A. Lau
Keyword(s):  
Design Method ◽  
Structural Parameters ◽  
Flexible Structures ◽  
Control Design ◽  
Input Shaping ◽  
Input Shaper ◽  
Modeling Errors ◽  
Parameter Variations ◽  
Damped Systems ◽  
Parameter Values

Input shaping has been shown to yield good performance in the control of flexible structures while being insensitive to modeling errors. However, previous studies do not take into account the distributions of the parameter variations. We develop a new input shaping method that allows the ranges of system parameter values to be weighted according to the expected modeling errors. Comparisons with previously proposed input shaper designs are presented to illustrate the qualities of the new input shaper design method. These new shapers will be shown to have better robustness under uncertainty in structural parameters and shorter shaper lengths for lightly damped systems. [S0022-0434(00)02201-2]

Experimental evaluation of time-varying impulse shaping with a two-link flexible manipulator

Robotica ◽  
1996 ◽  
Vol 14 (3) ◽  
pp. 339-345 ◽  
Author(s):  
Jung-Keun Cho ◽  
Youn-Sik Park
Keyword(s):  
Vibration Reduction ◽  
Vertical Plane ◽  
Joint Stiffness ◽  
Flexible Manipulator ◽  
Input Shaping ◽  
Time Varying ◽  
Modal Properties ◽  
Revolute Joints ◽  
Point Motion ◽  
Point To Point

SUMMARYIn the authors' previous paper,10 an input shaping method was presented to reduce motion-induced vibrations effectively for various classes of flexible systems. In this paper, the effectiveness of the shaping method is experimentally demonstrated with a two-link flexible manipulator systemThe manipulator for experiments includes two revolute joints and two flexible links, and moves on a vertical plane under gravity. An analytic model is developed considering the flexibility of the system and its joint stiffness in order to derive an appropriate estimation of dynamic modal properties. The input shaping method used in this work utilizes time-varying modal properties obtained from the model instead of the conventional input shaping method which employs time-invariant modal properties. A point-to-point motion is tested in order to show the effectivess of the proposed shaping method in vibration reduction during and after a given motion. The given reference trajectories are shaped to suppress the motion induced vibration. The test results demonstrate that the link vibration can be greatly suppressed during and after a motion, and the residual vibration reduction was observed more than 90% by employing this time-varying impulse shaping technique.

scholarly journals Combining Input Shaping and Adaptive Model-Following Control for Vibration Suppression

2021 ◽  
Vol 25 (1) ◽  
pp. 56-63
Author(s):  
Jinhua She ◽  
Lulu Wu ◽  
Zhen-Tao Liu ◽  
◽  
◽  
...  
Keyword(s):  
Vibration Suppression ◽  
Golden Section ◽  
Input Shaping ◽  
Adaptive Model ◽  
Servo Systems ◽  
Elastic Load ◽  
Model Following Control ◽  
Model Following ◽  
Input Shaper ◽  
Precision Motion

Vibration suppression in servo systems is significant in high-precision motion control. This paper describes a vibration-suppression method based on input shaping and adaptive model-following control. First, a zero vibration input shaper is used to suppress the vibration caused by an elastic load to obtain an ideal position output. Then, a configuration that combines input shaping with model-following control is developed to suppress the vibration caused by changes of system parameters. Finally, analyzing the percentage residual vibration reveals that it is effective to employ the sum of squared position error as a criterion. Additionally, a golden-section search is used to adjust the parameters of a compensator in an online fashion to adapt to the changes in the vibration frequency. A comparison with other input shaper methods shows the effectiveness and superiority of the developed method.

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.

scholarly journals Master-Slave Integrated Control for the Transverse Vibration of a Translational Flexible Manipulator Based on Input Shaping and State Feedback

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Jin-yong Ju ◽  
Wei Li ◽  
Yufei Liu ◽  
Chunrui Zhang
Keyword(s):  
State Feedback ◽  
Time Lag ◽  
The State ◽  
Flexible Manipulator ◽  
Input Shaping ◽  
Variable Load ◽  
Input Shaper ◽  
Mode Vibration ◽  
Integrated Controller ◽  
Load Conditions

The problem of the elastic vibration control for a translational flexible manipulator system (TFMS) under variable load conditions is studied. The input shaper can effectively filter out the vibration excitation components for the flexible manipulator in the driving signals, but the adaptability and rapidity of the conventional input shaper are poor because it is essentially an open-loop control mode and there are time-lag links inevitably. Thus, by combining the state feedback with the input shaping, a master-slave integrated controller of the TFMS is proposed. Moreover, in order to solve the time-lag effect of the conventional input shaper, based on the optimal algorithm, a two-mode vibration cascade shaper for the TFMS is designed. Then, under variable load conditions, the control effects of the conventional input shapers, the two-mode vibration cascade shaper, and the combination of the state feedback integral controller (SFIC) with the above shapers are investigated. The results show that the designed master-slave integrated controller has high robustness under variable load conditions and takes good account of the requirements of system response time and overshoot for achieving the goal of nonovershoot under fast response speed. Simulation experiment results verify the effectiveness of the designed controller.

scholarly journals Spacecraft vibration reduction using pulse-width pulse-frequency modulated input shaper

1997 ◽  
Author(s):  
Gangbing Song ◽  
Nick Buck ◽  
Brij Agrawal ◽  
Gangbing Song ◽  
Nick Buck ◽  
...  
Keyword(s):  
Pulse Width ◽  
Vibration Reduction ◽  
Pulse Frequency ◽  
Input Shaper

Reducing Trajectory Tracking Error of Flexible Mobile Robots Using Command Shaping With Error-Limiting Constraints

2017 ◽  
Author(s):  
Gerald Eaglin ◽  
Joshua Vaughan
Keyword(s):  
Mobile Robots ◽  
Trajectory Tracking ◽  
Tracking Error ◽  
Input Shaping ◽  
Flexible Systems ◽  
Command Shaping ◽  
Modeling Errors ◽  
Temporal Tracking ◽  
Point Motion ◽  
Point To Point

The ability to track a trajectory without significant error is a vital requirement for mobile robots. Numerous methods have been proposed to mitigate tracking error. While these trajectory-tracking methods are efficient for rigid systems, many excite unwanted vibration when applied to flexible systems, leading to tracking error. This paper analyzes a modification of input shaping, which has been primarily used to limit residual vibration for point-to-point motion of flexible systems. Standard input shaping is modified using error-limiting constraints to reduce transient tracking error for the duration of the system’s motion. This method is simulated with trajectory inputs constructed using line segments and Catmull-Rom splines. Error-limiting commands are shown to improve both spatial and temporal tracking performance and can be made robust to modeling errors in natural frequency.

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