Command Shaping for Flexible Systems Subject to Constant Acceleration Limits

2008 ◽  
Vol 130 (5) ◽  
Author(s):  
Jon Danielson ◽  
Jason Lawrence ◽  
William Singhose
Keyword(s):  
Effective Means ◽  
Input Shaping ◽  
Constant Force ◽  
Flexible Systems ◽  
Common Occurrence ◽  
Constant Acceleration ◽  
Command Shaping ◽  
Input Shaper ◽  
Drive Systems ◽  
Theoretical Results

Input shaping is an effective means of eliminating vibration in many types of flexible systems. This paper discusses how input shaper performance is affected by a fixed acceleration limit. This type of limit is a common occurrence in many mechanical drive systems because it corresponds to a constant force or torque input. It is shown that some input shapers are not affected by an acceleration limit under certain conditions. A test criterion is developed to determine what types of input shapers are negatively affected, and a method is proposed to compensate for the detrimental effects of the constant acceleration limit. Experimental results from an industrial crane support the main theoretical results.

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.

Input Shaping for Nonlinear Drive Systems

2006 ◽  
Author(s):  
Thomas H. Bradley ◽  
Terry Hall ◽  
Qiulin Xie ◽  
William Singhose ◽  
Jason W. Lawrence
Keyword(s):  
Input Shaping ◽  
Bridge Crane ◽  
Flexible Systems ◽  
Acceleration And Deceleration ◽  
New Type ◽  
Drive Systems ◽  
Input Command

Input shaping is effective at eliminating vibration in many types of flexible systems. This paper discusses how input shaping is affected by actuators with unequal acceleration and deceleration dynamics. It is shown that traditional Unity Magnitude Zero Vibration (UMZV) shapers have degraded performance when used with such actuators. A new type of UMZV shaped input command is developed to compensate for the nonlinearity. Experiments on a portable bridge crane demonstrate the effectiveness of the proposed approach.

Adaptive Input Shaping for Nonlinear Systems: A Case Study

2006 ◽  
Vol 129 (2) ◽  
pp. 219-223 ◽  
Author(s):  
John Stergiopoulos ◽  
Anthony Tzes
Keyword(s):  
System Theory ◽  
Nonlinear Systems ◽  
Input Shaping ◽  
Relative Time ◽  
Pendulum System ◽  
Input Shaper ◽  
Command Input ◽  
Damped Systems ◽  
Theoretical Results

Input shaping is a technique that seeks to reduce residual vibrations of lightly damped systems through modification of the command input to the system. Although several input shaping techniques have been derived primarily from linear system theory, theoretical results are hard to be traced for their application to nonlinear systems. In most of the reported cases, a fixed shaper is designed based on the linearized version around an operating point of the nonlinear system. In this paper, an adaptive form of the input shaper is proposed for a class of nonlinear lightly damped systems. The adaptive shaper adjusts the magnitude and relative time difference between its impulses according to the instant frequency and damping of the linearized systems. The efficacy of the proposed scheme and its comparison to a fixed shaper is investigated through its application to a pendulum system. The adaptive shaper’s parameters vary according to the pendulum’s angle. The illustrative examples indicate the deficiencies of the fixed case and demonstrate the efficacy of the designed controller.

Three-step input shaper for damping tubular step motor vibrations

2007 ◽  
Vol 221 (1) ◽  
pp. 1-9 ◽  
Author(s):  
S S Gürleyük ◽  
R Hacioglu ◽  
Ş Cinal
Keyword(s):  
Experimental Results ◽  
Step Motor ◽  
Input Shaping ◽  
Flexible Systems ◽  
Step Input ◽  
Shaping Technique ◽  
Input Shaper

Input shaping technique is used to improve the performance of many flexible systems. Employing specified train of impulses convolved with a reference command can effectively reduce residual vibrations. Zero vibration, zero vibration derivative and specified insensitive or extra insensitive, and zero vibration derivative-derivative shapers are wellknown types of input shapers. These shapers improve the robustness of the system with respect to modelling errors. In this article, a coherent input shaping scheme with all positive threeimpulse sequences is developed, which is preferable to derivative shaper types. The proposed method is used for damping the tubular step motor vibrations. The method allows generating the impulse amplitudes without additional derivative constraints. The technique is also evaluated by analysing the robustness. Experimental results show the efficiency of the proposed method.

DYNAMICS OF A2 FINGER PULLEY RUPTURE

2007 ◽  
Vol 07 (01) ◽  
pp. 75-87 ◽  
Author(s):  
MING A. TAN ◽  
FRANZ K. FUSS ◽  
GÜNTHER NIEGL
Keyword(s):  
Mechanical Properties ◽  
Mathematical Model ◽  
Initial Rate ◽  
Constant Force ◽  
Common Occurrence ◽  
Pulley System ◽  
Convergence Test ◽  
A2 Pulley ◽  
The Common ◽  
Rupture Mechanism

A mathematical model of the A2 pulley system will enable us to have a better understanding of the mechanics of the pulley-tendon system and provide us with insights of the pulley rupture mechanism. The A2 pulley was modeled based on parallel pulley fibers attached to a phalanx with a tendon passing them. Mechanical properties of the pulleys such as stiffness, strength and friction were included in the model. A convergence test was done to ensure the accuracy of the test. The model managed to show high loads on flexed finger may lead to pulley ruptures. Further studies on the rupture mechanism showed that pulley ruptures are self-propagating when a constant force is applied and the rate of rupture increases, as fewer intact fibers are present to support the load. The initial rate of propagation is much slower and this accelerates as more fibers are ruptured. This explains the common occurrence of partial pulley ruptures.

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.

Sign in / Sign up

Export Citation Format

Share Document