Command Shaping Slewing Motions for Tower Cranes

2010 ◽  
Vol 132 (1) ◽  
Author(s):  
Jason Lawrence ◽  
William Singhose
Keyword(s):  
Nonlinear Dynamics ◽  
Rotational Motion ◽  
Effective Control ◽  
Input Shaping ◽  
Residual Vibration ◽  
Command Shaping ◽  
Tower Crane ◽  
Control Scheme ◽  
Point To Point ◽  
Gantry Cranes

Input shaping has been shown to be a practical and effective control scheme for reducing payload swing on industrial bridge and gantry cranes. However, when applied to tower cranes, standard input shapers will have degraded performance due to the nonlinear dynamics of rotational motion. To alleviate this problem, two new command generators for tower cranes are developed for a point-to-point slewing motion. It is shown that standard shaping techniques greatly reduce oscillation and the new tower crane command generators cause even less residual vibration. Simulations and experiments verify the results.

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.

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.

An Input Shaping Control Scheme with Application on Overhead Cranes

2019 ◽  
Vol 20 (5) ◽  
pp. 561-573 ◽  
Author(s):  
Khalid Alghanim ◽  
Abdullah Mohammed ◽  
Masood Taheri Andani
Keyword(s):  
Optimization Technique ◽  
Sensitivity Analyses ◽  
Input Shaping ◽  
Residual Vibration ◽  
System Sensitivity ◽  
Cable Length ◽  
Control Scheme ◽  
Input Acceleration ◽  
Input Shaping Control ◽  
Continuous Range

AbstractA new optimization technique is developed to generate a step-input acceleration function for an input shaping harmonic system. This approach is integrated into an overhead crane model for a rest-to-rest maneuver with standard and nonstandard maneuver settings. The proposed method guarantees the satisfaction of the system constraints and desired final conditions, while it minimizes the system sensitivity to crane cable-length variations. The minimal system sensitivity is achieved through an optimization algorithm that provides zero vibration and a minimum integral of system sensitivity over a continuous range of crane cable length. Numerical simulations are conducted to demonstrate the feasibility of the proposed shaper in eliminating the residual vibration at the end of a programmed maneuver. Sensitivity analyses are also performed to verify the robustness of the new shaper. In comparison to the previous shapers, the new methodology is significantly less sensitive and can effectively handle different arbitrary maneuver times.

New Command Shaping Methods for Reduced Vibration of a Suspended Payload With Constrained Trolley Motion

2007 ◽  
Author(s):  
Aaron R. Enes ◽  
Timothy Y. Hsu ◽  
Angela A. Sodemann
Keyword(s):  
System Modeling ◽  
Small Scale ◽  
Residual Vibration ◽  
Conveyor System ◽  
Command Shaping ◽  
Common Task ◽  
Modeling Errors ◽  
Point To Point ◽  
Manufacturing Environments ◽  
Command Signal

In manufacturing environments, a common task is to quickly move a suspended payload point-to-point along a fixed overhead conveyor track without inducing significant payload vibration. Recent research in command shaping has shown remarkably effective ways to reduce the swing of a suspended payload providing the motion of the trolley is not constrained. However, the development of a command shaper where the trajectory of the trolley is constrained to follow a fixed curvilinear path has not been explored. This paper will present the development of a simple feedforward command shaper for fast, low vibration, point-to-point movement of a payload suspended from a trolley constrained to follow a fixed generalized path. The command shaping method involves modifying the command signal by convolving it with a series of impulses. Prior work has suggested command shaping to be very effective for fast, low-vibration movement of flexible systems. In this paper, command shaping methods are applied to an overhead conveyor system constrained to move along a fixed curvilinear path. Two new command shapers are presented for canceling payload vibration induced by motion of the trolley along the path. The designed Tangential Vibration (TV) shaper reduces payload vibrations induced by tangential accelerations of the trolley along the path, while the Centripetal-Tangential Vibration (CTV) shaper reduces vibrations induced by both tangential and centripetal accelerations. A key result of this study is that a command shaper having at least three impulses is required to yield zero residual vibration for motion along a curvilinear path. A simple pendulum payload attached to an actual small-scale overhead trolley following a constrained path is used to evaluate the performance of the designed command shapers. It is shown that the designed shapers significantly reduce payload swing compared to unshaped performance. An experimental sensitivity analysis shows the designed shapers are robust to system modeling errors and variations in path parameters.

Model Reference Control With Command Shaping for a Micro-Electromagnetic Actuator With Input Constraints

2019 ◽  
Author(s):  
Gerald Eaglin ◽  
Joshua Vaughan
Keyword(s):  
Reference Model ◽  
Electromagnetic Actuator ◽  
Input Shaping ◽  
Input Constraints ◽  
Residual Vibration ◽  
Model Reference ◽  
Command Shaping ◽  
Model Reference Control ◽  
Limiting Property ◽  
Nonlinear Plants

Abstract Model Reference Control is used to force a system to track the response of an assigned reference model, where the reference model is often designed to reflect the desired properties of the system. If a linear reference model is used, Model Reference Control has a linearizing effect for nonlinear plants, allowing it to be cascaded with linear controllers. Model Reference Control has been used to force nonlinear flexible systems to behave linearly such that input shaping can be used to limit residual vibration. However, when a system encounters saturation limits, the vibration limiting property of input shaping is degraded. This paper proposes Model Reference Control with an adaptive input shaping method to account for saturation by modifying the input shaper after saturation has been encountered. Simulations are presented to illustrate the effectiveness of this method in canceling residual vibration for a nonlinear electromagnetic actuator subject to input constraints.

Closed-Loop Input Shaping Control of Vibration in Flexible Structures via Adaptive Sliding Mode Control

2012 ◽  
Vol 19 (2) ◽  
pp. 221-233 ◽  
Author(s):  
Ming-Chang Pai
Keyword(s):  
Closed Loop ◽  
Sliding Mode ◽  
Flexible Structures ◽  
Adaptive Sliding Mode Control ◽  
Input Shaping ◽  
Parameter Uncertainties ◽  
Residual Vibration ◽  
Shaping Technique ◽  
Control Scheme ◽  
Input Shaping Control

Input shaping technique is widely used in reducing or eliminating residual vibration of flexible structures. The exact elimination of the residual vibration via input shaping technique depends on the amplitudes and instants of impulse application. However, systems always have parameter uncertainties which can lead to performance degradation. In this paper, a closed-loop input shaping control scheme is developed for uncertain flexible structures. The algorithm is based on input shaping control and adaptive sliding mode control. The proposed scheme does not need a priori knowledge of upper bounds on the norm of the uncertainties, but estimates them by using the adaptation technique. This scheme guarantees closed-loop system stability, and yields good performance and robustness in the presence of parameter uncertainties and external disturbances as well. Furthermore, it is shown that increasing the robustness to parameter uncertainties does not lengthen the duration of the impulse sequence. Simulation results demonstrate the efficacy of the proposed closed-loop input shaping control scheme.

scholarly journals An Adjustable Zero Vibration Input Shaping Control Scheme for Overhead Crane Systems

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Abdullah Mohammed ◽  
Khalid Alghanim ◽  
Masood Taheri Andani
Keyword(s):  
Sensitivity Analysis ◽  
Control System ◽  
System Performance ◽  
Input Shaping ◽  
Overhead Crane ◽  
Shaping Technique ◽  
Design Flexibility ◽  
Control Scheme ◽  
Point To Point ◽  
Input Shaping Control

This article presents a modified zero vibration (ZV) input shaping technique to address the sensitivity and flexibility limitations of the classic ZV shapers commonly implemented in overhead crane applications. Starting with the classical ZV formulation, new parameters are introduced to optimize the control system performance according to a versatile objective function. The new shaper enhances the design flexibility and operational domain of the shaper, while it inherits the robustness properties and computational efficiency of the ZV scheme. Unlike the original ZV shaper, the proposed shaper allows for the point-to-point maneuver time to be fixed. The sensitivity analysis of the controller confirms that the new shaper effectively reduces the ZV sensitivity to the cable length variations.

Effective Feedforward/Feedback Controller Design With Command Shaping to Reduce Residual Vibration

Manufacturing ◽  
2003 ◽  
Author(s):  
Peter H. Meckl ◽  
Young Joo Shin
Keyword(s):  
Control Strategy ◽  
High Speed ◽  
Controller Design ◽  
High Volume ◽  
Feedback Controller ◽  
Residual Vibration ◽  
Command Shaping ◽  
Minimum Residual ◽  
High Volume Production ◽  
Point To Point

Many manufacturing devices must execute motions as quickly as possible to achieve profitable high-volume production. This paper develops a control strategy that combines feedforward and feedback control with command shaping. First, the feedback controller is designed to increase damping and eliminate steady-state error. Next, the feedforward controller is designed to speed up the transient response. Finally, an appropriate reference profile is generated using command-shaping techniques to ensure fast point-to-point motions with minimum residual vibration. The particular focus of the paper is to understand the interactions between these individual control components. The resulting control strategy is demonstrated on a model of a high-speed semiconductor manufacturing machine.

Quantitative Feedback Input Shaping for Flexible-Joint Robot Manipulator

2016 ◽  
Vol 138 (6) ◽  
Author(s):  
Withit Chatlatanagulchai ◽  
Dumrongsak Kijdech ◽  
Takat Benjalersyarnon ◽  
Supparat Damyot
Keyword(s):  
Reference Model ◽  
Robot Manipulator ◽  
Simple Zero ◽  
Input Shaping ◽  
Residual Vibration ◽  
Flexible Joint ◽  
Input Shaper ◽  
Time Varying Systems ◽  
Shaping System ◽  
Point To Point

Input shaping technique has been applied to flexible-joint robot to suppress its residual vibration from fast point-to-point movement. Input shaping performance deteriorates when the knowledge of the mode parameters of the robot is not accurate. Several robust input shapers were proposed at the expense of longer move time. A novel input shaping system, consisting of a quantitative feedback controller, a feed-forward reference model, and a simple zero-vibration (ZV) input shaper, is proposed in this paper. Advantages over the existing robust input shapers include toleration of substantially larger amount of uncertainty in the mode parameters, shorter move time that does not increase with insensitivity, application to nonlinear and time-varying systems, and suppression of vibration induced by disturbance and noise.

A Multi-Mode Smooth Command Shaper With an Adjustable Maneuver Time

2015 ◽  
Author(s):  
Khaled A. Alhazza ◽  
Ziyad N. Masoud
Keyword(s):  
Resonant Frequency ◽  
Life Time ◽  
Degree Of Freedom ◽  
Input Shaping ◽  
Residual Vibration ◽  
Command Shaping ◽  
Controller Performance ◽  
Multimode System ◽  
Multi Mode

Input shaping and command shaping are important techniques in reducing residual vibrations in rest-to-rest maneuvers. Jerks in these shapers can reduce the life time for the crane motors and electronic boards. In this work, a totally smooth command shaper with an independent adjustable maneuvering time is introduced to eliminate residual vibration in multimode system. The proposed technique is solved analytically and simulated numerically through several examples. Furthermore, the proposed technique requires only the resonant frequency of the system to produce a control profile. The results through several examples show a great controller performance. It is important to mention that the proposed controller can be applied on any discretized multi-degree-of-freedom system.

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