Reducing Overshoot in Human-Operated Flexible Systems

2010 ◽  
Vol 133 (1) ◽  
Author(s):  
Joshua Vaughan ◽  
Paul Jurek ◽  
William Singhose
Keyword(s):  
Additional Constraint ◽  
Task Completion ◽  
Input Shaping ◽  
Bridge Crane ◽  
New Class ◽  
Input Shaper ◽  
Theoretical Predictions ◽  
Acceleration And Deceleration ◽  
Improved Performance ◽  
Performance Results

Input shaping accomplishes vibration reduction by slightly increasing the acceleration and deceleration periods of the command. The increase in the deceleration period can lead to system overshoot. This paper presents a new class of reduced-overtravel input shapers that are designed to reduce shaper-induced overtravel from human-operator commands. During the development of these new shapers, an expression for shaper-induced overtravel is introduced. This expression is used as an additional constraint in the input-shaper design process to generate the reduced-overtravel shapers. Experiments from a portable bridge crane verify the theoretical predictions of improved performance. Results from a study of eight industrial bridge crane operators indicate that utilizing the new reduced-overtravel input shapers dramatically reduces task completion time, while also improving positioning accuracy.

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.

Input Shaping Control of Double-Pendulum Bridge Crane Oscillations

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
William Singhose ◽  
Dooroo Kim ◽  
Michael Kenison
Keyword(s):  
Single Mode ◽  
Input Shaping ◽  
Double Pendulum ◽  
Bridge Crane ◽  
Efficient Operation ◽  
Input Shaper ◽  
Large Amplitude Oscillation ◽  
Control Research ◽  
Pendulum Dynamics ◽  
Input Shaping Control

Large amplitude oscillation of crane payloads is detrimental to safe and efficient operation. Under certain conditions, the problem is compounded when the payload creates a double-pendulum effect. Most crane control research to date has focused on single-pendulum dynamics. Several researchers have shown that single-mode oscillations can be greatly reduced by properly shaping the inputs to the crane motors. This paper builds on those previous developments to create a method for suppressing double-pendulum payload oscillations. The input shaping controller is designed to have robustness to changes in the two operating frequencies. Experiments performed on a portable bridge crane are used to verify the effectiveness of this method and the robustness of the input shaper.

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.

Operator Testing on Dual-Hoist Cranes Moving Triangular Payloads

2015 ◽  
Author(s):  
Caroline Rhee ◽  
Alexander S. Miller ◽  
William Singhose
Keyword(s):  
Completion Time ◽  
Operating Conditions ◽  
Task Completion ◽  
Input Shaping ◽  
Bridge Crane ◽  
Complex Dynamic ◽  
Safety Hazards ◽  
Operator Training ◽  
Oscillation Control ◽  
Time Required

Certain heavy-lifting applications require the coordinated movement of multiple cranes. Such tasks dramatically increase the complexity of crane operation, especially when the payload has a non-uniform shape. Therefore, controlling such a complex dynamic system requires skilled operators. However, even with extensive operator training, manipulating a crane with a large payload is difficult and presents serious safety hazards. This paper studies the dynamic behavior of a dual-hoist bridge crane moving triangular payloads. Test subjects used a wireless controller to move a dual-hoist crane with a triangular payload. They drove the payload through an obstacle course under various operating conditions. The time required to complete the course and the operator effort were recorded. Test runs were completed with and without input-shaping oscillation control. The result shows that using input-shaping oscillation control significantly reduces not only the task completion time but also the number of button pushes.

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.

Damping and Bandgap Characteristics of a Viscoelastic Tensegrity Damper

2021 ◽  
pp. 1-47
Author(s):  
Mohamed Raafat ◽  
Amr Baz
Keyword(s):  
Mathematical Model ◽  
Material Characterization ◽  
Structural Vibrations ◽  
New Class ◽  
Structural Applications ◽  
Theoretical Predictions ◽  
Specific Frequency ◽  
The Mathematical Model ◽  
Theory And Experiments

Abstract A theoretical and experimental investigation of a new class of a tensegrity-based structural damper is presented. The damper is not only capable of attenuating undesirable structural vibrations, as all conventional dampers, but also capable of completely blocking the transmission of vibration over specific frequency bands by virtue of its periodicity. Such dual functionality distinguishes the tensegrity damper over its counterparts of existing structural dampers. Particular emphasis is placed here in presenting the concept and developing the mathematical model of the dynamics of a unit cell the damper. The model is then coupled with a Floquet-Bloch analysis in order to identify the bandgap characteristics of the damper. The predictions of the mathematical model are validated experimentally using a prototype of the damper which is built using 3D printing. A comprehensive material characterization of the damper is performed followed by a detailed extraction of the static and dynamic behavior of the damper in order to validate the theoretical predictions. Close agreement is observed between theory and experiments. The developed theoretical and experimental techniques provide invaluable means for the design of this new class of dampers particularly for critical structural applications.

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.

TASK COMPLEXITY, LANGUAGE-RELATED EPISODES, AND PRODUCTION OF L2 SPANISH VOWELS

2016 ◽  
Vol 39 (2) ◽  
pp. 347-380 ◽  
Author(s):  
Megan Solon ◽  
Avizia Y. Long ◽  
Laura Gurzynski-Weiss
Keyword(s):  
Statistical Difference ◽  
Task Complexity ◽  
Task Completion ◽  
Complex Task ◽  
Vowel Production ◽  
Complex Tasks ◽  
Information Gap ◽  
Theoretical Predictions ◽  
L2 Spanish ◽  
L2 Pronunciation

This study tests the theoretical predictions regarding effects of increasing task complexity (Robinson, 2001a, 2001b, 2007, 2010; Robinson & Gilabert, 2007) for second language (L2) pronunciation. Specifically, we examine whether more complex tasks (a) lead to greater incidence of pronunciation-focused language-related episodes (LREs) and (b) positively impact accuracy of phonetic form during task completion. Seventeen dyads of intermediate L2 Spanish learners completed simple (+few elements) and complex (-few elements) information-gap map tasks in which the pronunciation of Spanish vowels was made task essential through the inclusion of minimal pair street names (e.g.,Calle Copa“Copa Street” andCalle Capa“Capa Street”). Results revealed no statistical difference in learner-produced pronunciation-related LREs in the simple and complex tasks. Vowel production, however, moved in a targetlike direction for one of five segments (/e/) during the complex task. Results therefore point to some benefits of task complexity manipulations for L2 pronunciation.

Crane Operation Using Hand-Motion and Machine Vision

2009 ◽  
Author(s):  
Kelvin Chen Chih Peng ◽  
William Singhose ◽  
Jonathan Fonseca
Keyword(s):  
Experimental Data ◽  
Image Processing ◽  
Motion Control ◽  
Processing System ◽  
Bridge Crane ◽  
Hand Motion ◽  
Input Shaper ◽  
Control Interface ◽  
New Type ◽  
Human Operators

Payload oscillation inherent to all cranes makes it challenging for human operators to manipulate payloads quickly, accurately, and safely. A new type of crane control interface that allows an operator to drive a crane by moving his or her hand freely in space has been implemented on an industrial bridge crane. An image processing system tracks the movement of a glove worn on the operator’s hand and its position is then used to drive the crane. Matlab simulations of the crane dynamics and hand-motion control were compared with actual experimental data. The results show that a combination of aggressive PD gains and an input shaper is able to generate the desired characteristics of fast payload response and low residual oscillations.

Sign in / Sign up

Export Citation Format

Share Document