A Continuous Modulated Wave-Form Command Shaping for Damped Overhead Cranes

2011 ◽  
Author(s):  
Khaled A. Alhazza ◽  
Asmahan H. Al-Shehaima ◽  
Ziyad N. Masoud
Keyword(s):  
Control Strategy ◽  
Damping Ratio ◽  
Harmonic Oscillators ◽  
Wave Form ◽  
Double Step ◽  
Command Shaping ◽  
Overhead Cranes ◽  
Input Shaper ◽  
Displacement Profile ◽  
System Properties

A new command-shaping control strategy for oscillation reduction of damped harmonic oscillators is derived and implemented on damped overhead cranes. The effect of damping on the shaper frequency and duration is investigated. The performance of the proposed simper is simulated numerically and compared with the classical double-step input-shaper for different system properties. It was shown that, the proposed wave-form command profiles are capable of eliminating the travel and residual oscillations for systems with different damping ratio. Further, unlike traditional impulse and step command shapers, the proposed command profiles have smoother intermediate acceleration, velocity, and displacement profile.

A Novel Wave-Form Command-Shaping Control With Application on Overhead Cranes

2010 ◽  
Author(s):  
Khaled A. Alhazza ◽  
Ziyad N. Masoud
Keyword(s):  
Harmonic Oscillator ◽  
Control Strategy ◽  
Wave Form ◽  
Overhead Crane ◽  
Command Shaping ◽  
Overhead Cranes ◽  
Simple Harmonic Oscillator

In this work, a novel continuous command-shaping control strategy for a simple harmonic oscillator is proposed and implemented on an overhead crane model. A Wave-Form (WF) acceleration command profile is derived analytically, and its performance is validated numerically. To enhance the performance of the proposed command-shaping control strategy, a Modulated Wave-Form (MWF) acceleration command profile is derived. It was determined that the proposed Wave-Form and Modulated Wave-Form command profiles are capable of eliminating the travel and residual oscillations. Furthermore, unlike traditional impulse and step command-shaping, the proposed command profiles have smoother intermediate acceleration, velocity, and displacement profiles.

Command Shaping Control of a Vertically Rotating Flexible Beam

2019 ◽  
Author(s):  
Khaled A. Alhazza
Keyword(s):  
Initial Conditions ◽  
Equation Of Motion ◽  
Wave Form ◽  
Flexible Beam ◽  
Beam Length ◽  
Rotating Beam ◽  
Double Step ◽  
Higher Modes ◽  
Command Shaping ◽  
System Equation

Abstract Vertically rotating flexible beam under the effect of gravity adds some challenges to the existing input- and command shaping techniques. Classical shapers usually have zero initial conditions while vertically rotating beam may have initial or final deflections. These conditions may introduce large residual vibrations at the end of rest-to-rest maneuvers. Furthermore, the system contains some nonlinearities that may reduce the effectiveness of classical input- and command-shapers. In this work, a waveform command shaping profile is used initially and then optimized to reduce rest-to-rest residual vibrations of a vertically rotating flexible beam. The system equation of motion is determined, discretized, and then linearized to find an initial command shaper. The parameters of the proposed command shaper is then optimized to find a better performance. Only the first mode is considered in this work since higher modes usually have negligible amplitudes. To show the importance of the proposed work, comparisons between the uncontrolled shaper, double step shaper, smooth wave form command shaping, and the optimized command shaping are performed. The proposed technique is tested numerically using two cases, with different maximum velocities, flexible beam length, and acceleration times. Results show that the effectiveness of the proposed technique in reducing residual vibrations in rest-to-rest maneuvers.

A Smooth Wave-Form Command Shaping Control

2013 ◽  
Author(s):  
Khaled A. Alhazza ◽  
Ziyad N. Masoud ◽  
Nehal Alotaibi
Keyword(s):  
Experimental Results ◽  
Harmonic Oscillators ◽  
Wave Form ◽  
Overhead Crane ◽  
Scaled Model ◽  
Smoothing Techniques ◽  
Command Shaping ◽  
Shaping Technique ◽  
Multi Mode ◽  
Smooth Acceleration

To avoid excitation of higher modes of flexible and multi-mode systems, it is important to eliminate sudden and jerky inputs. To achieve this goal, researchers tend to use different smoothing techniques to reduce the effect of the command roughness. In this work, a new smooth command-shaping technique for oscillation reduction of simple harmonic oscillators is proposed. A continuous smooth wave-form acceleration command-shaper is proposed. The shaper parameters are tuned to eliminate residual vibrations in rest-to-rest maneuvers. The performance of the proposed shaper is determined analytically, simulated numerically, and validated experimentally on a scaled model of an overhead crane. Results obtained show that the proposed smooth wave-form shaper is capable of eliminating travel and residual oscillations. Furthermore, unlike traditional step command shapers, the proposed command profiles have completely smooth acceleration, velocity, and displacement profiles. Experimental results demonstrate the ability of our proposed smooth wave-form commands to eliminate residual vibrations at the end of rest-to-rest maneuvers.

A Discretized Optimization Strategy for Rest-to-Rest Maneuvers of Overhead Cranes Considering the Effect of Damping

2015 ◽  
Author(s):  
Khaled A. Alghanim ◽  
Khaled A. Alhazza ◽  
Ziyad N. Masoud
Keyword(s):  
Damping Ratio ◽  
Equations Of Motion ◽  
Maximum Velocity ◽  
System Response ◽  
Optimization Strategy ◽  
Time Step ◽  
Natural Period ◽  
Overhead Cranes ◽  
Finite Step ◽  
Acceleration Profile

An optimization strategy to reduce residual vibration of rest-to-rest maneuvers of overhead cranes is proposed. The proposed technique is based on generating shaped acceleration commands for a simple harmonic oscillator with damping included. Furthermore, the proposed technique solves the problem of discrete signal commands that result from using slow digital to analog convertors on real cranes. A discretized acceleration profile is derived analytically using finite step segments. These segments are integrated into a matrix, which is then coupled with a system response matrix through the system’s equations of motion. The resulting input acceleration matrix is then optimized to satisfy rest-to-rest maneuver conditions. The profile designer can control many parameters such as maneuver duration, discrete time step, hoisting speed, damping ratio, maximum velocity and acceleration. Unlike traditional command shapers, the proposed shaped profiles are independent of the natural period of the system, i.e., the acceleration profile duration is designer selectable. Through several examples, the performance of the proposed controller is validated numerically. Results show that the proposed shaping technique can effectively eliminate residual vibrations in rest-to-rest maneuvers of damped single-degree-of-freedom systems.

scholarly journals Payload swing control of a tower crane using a neural network–based input shaper

2020 ◽  
Vol 53 (7-8) ◽  
pp. 1171-1182 ◽  
Author(s):  
SM Fasih ◽  
Z Mohamed ◽  
AR Husain ◽  
L Ramli ◽  
AM Abdullahi ◽  
...  
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Natural Frequency ◽  
Damping Ratio ◽  
Parameter Uncertainties ◽  
Cable Length ◽  
Tower Crane ◽  
Input Shaper ◽  
Average Operating ◽  
Artificial Neural

This paper proposes an input shaping technique for efficient payload swing control of a tower crane with cable length variations. Artificial neural network is utilized to design a zero vibration derivative shaper that can be updated according to different cable lengths as the natural frequency and damping ratio of the system changes. Unlike the conventional input shapers that are designed based on a fixed frequency, the proposed technique can predict and update the optimal shaper parameters according to the new cable length and natural frequency. Performance of the proposed technique is evaluated by conducting experiments on a laboratory tower crane with cable length variations and under simultaneous tangential and radial crane motions. The shaper is shown to be robust and provides low payload oscillation with up to 40% variations in the natural frequency. With a 40% decrease in the natural frequency, the superiority of the artificial neural network–zero vibration derivative shaper is confirmed by achieving at least a 50% reduction in the overall and residual payload oscillations when compared to the robust zero vibration derivative and extra insensitive shapers designed based on the average operating frequency. It is envisaged that the proposed shaper can be further utilized for control of tower cranes with more parameter uncertainties.

Stability Analysis of Bridge Crane Hoists

2014 ◽  
Vol 543-547 ◽  
pp. 111-114
Author(s):  
Yun Yan Song
Keyword(s):  
Control Strategy ◽  
Pid Control ◽  
Single Neuron ◽  
Bridge Crane ◽  
Matlab Simulation ◽  
Factors Affecting ◽  
Overhead Cranes ◽  
Depth Study ◽  
Main Factors ◽  
Single Neuron Pid

Hoist bridge crane swinging phenomenon often occurs during the operation, making the work more difficult, there is a certain danger. To solve this problem, anti-sway system for overhead cranes depth study to identify the main factors affecting heavy lifting swinging; proposed single neuron PID control strategy, while using MATLAB simulation used to verify the reliability of the method.

scholarly journals Positive Position Feedback Control for High-Amplitude Vibration of a Flexible Beam to a Principal Resonance Excitation

2010 ◽  
Vol 17 (2) ◽  
pp. 187-203 ◽  
Author(s):  
Li Jun
Keyword(s):  
Feedback Control ◽  
Control Strategy ◽  
Damping Ratio ◽  
High Amplitude ◽  
Control Technique ◽  
Feedback Gain ◽  
Flexible Beam ◽  
Positive Position Feedback ◽  
Position Feedback ◽  
Amplitude Vibration

The application of active linear absorber based on positive position feedback control strategy to suppress the high-amplitude response of a flexible beam subjected to a primary external excitation is developed and investigated. A mathematical nonlinear model that describes the single-mode dynamic behavior of the beam is considered. The perturbation method of multiple scales is employed to find the general nonlinear response of the system and four first-order differential equations governing the amplitudes and phases of the responses are derived. Then a stability analysis is conducted for the open- and closed-loop responses of the system and the performance of the control strategy is analyzed. A parametric investigation is carried out to investigate the effects of changing the damping ratio of the absorber and the value of the feedback gain as well as the effect of detuning the frequency of the absorber on the responses of the system. It is demonstrated that the positive position feedback control technique is effective in reducing the high-amplitude vibration of the model and the control scheme possesses a wide suppression bandwidth if the absorber's frequency is properly tuned. Finally, the numerical simulations are performed to validate the perturbation solutions.

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