A Smooth Multimode Waveform Command Shaping Considering the Effect of Hoisting

2016 ◽  
Author(s):  
Khaled A. Alhazza
Keyword(s):  
Equations Of Motion ◽  
Optimization Technique ◽  
Large Body ◽  
Single Mode ◽  
Input Shaping ◽  
Double Pendulum ◽  
Scaled Model ◽  
Command Shaping ◽  
Varying Coefficients ◽  
Time Varying Coefficients

Input shaping and command shaping control techniques are the subject of large body of research in the past several decades. Most of the research is dedicated to time invariant single-mode systems. For a double pendulum hoisting system, hoisting results in a complex system of equations of motion. For rest-to-rest maneuvers, it is a common practice in research to split maneuvers into three consecutive independent stages; hoisting up the payload from an initial position, moving it horizontally, and finally lowering it to a final location. Input shaping is used is the horizontal travel motion stage to eliminate inertia excited vibrations. Although, this approach is effective, significant time penalties are involved due to the split motion approach. Further, traditional input shaping techniques involve significant jerks in the motion commands. To overcome these drawbacks, a new smooth waveform command shaping technique is proposed to enable concurrent hoisting and travel actions. The equations of motion including time varying coefficients are derived and used to determine the coefficients of an optimum waveform shaped command profile. Genetic algorithm optimization technique is used to find the optimal values of the command parameters. The initial values of these parameters are determined assuming a constant cable length. The effectiveness of the shaped command is demonstrated through numerical simulations and experiments on a scaled model of double pendulum using different maneuvers involving simultaneous travel and linear hoisting.

Experimental and Numerical Validation on a Continuous Modulated Wave-Form Command Shaping Control Considering the Effect of Hoisting

2013 ◽  
Author(s):  
Khaled A. Alhazza
Keyword(s):  
Optimization Technique ◽  
Large Body ◽  
Initial Point ◽  
Pattern Search ◽  
Wave Form ◽  
Input Shaping ◽  
Time Varying ◽  
Scaled Model ◽  
Command Shaping ◽  
Cable Length

A large body of research has been dedicated to input-shaping control techniques. Most of the research assumes constant cable length, due to the complexity of the dynamics associated with changing cable length (hoisting). Current techniques tend to split maneuvers into three consecutive stages, raising the payload from an initial point, then moving it horizontally using input-shaping, and finally lowering it to a final location. These techniques are effective, however, they involve significant time penalties. In this work, a new modulated wave-form command shaping technique is proposed to enable concurrent hoisting and travel maneuvers. The time varying ordinary differential equation of motion is derived and used to determine the parameters and frequency of the proposed shaped-command. Assuming linear hoisting, the equation is solved analytically by assuming small changes in the time varying terms. This approach results in some error which can be corrected by using pattern search optimization technique. It is shown that, the proposed method is capable of eliminating the travel and residual oscillations for different maneuvers involving linear hoisting. Performance is simulated numerically and validated experimentally on a scaled model of an overhead crane.

Command-Shaping Control System for Double-Pendulum Gantry Cranes

2011 ◽  
Author(s):  
Ziyad N. Masoud ◽  
Khaled A. Alhazza
Keyword(s):  
Closed Loop ◽  
Single Mode ◽  
Feedback System ◽  
Mode Frequency ◽  
Gantry Crane ◽  
Necessary Condition ◽  
Double Pendulum ◽  
Double Step ◽  
Scaled Model ◽  
Command Shaping

Traditionally, multi-mode command-shaping controllers are tuned to the system frequencies. This work suggests an opposite approach. A frequency-modulation (FM) strategy is developed to tune the system frequencies to match the frequencies eliminated by a single-mode command-shaper. The shaper developed in this work is based on a double-step command-shaping strategy. Using the FM Shaper, a simulated feedback system is used to modulate the closed-loop frequencies of a simulated double-pendulum model to the point where the closed-loop second mode frequency becomes an odd multiple of the closed-loop first mode frequency, which is the necessary condition for a satisfactory performance of a single-mode command-shaper. The double-step command-shaper is based on the closed-loop first mode frequency. The input commands to the plant of the simulated closed-loop system are then used to drive the actual double-pendulum. Performance is validated experimentally on a scaled model of a double-pendulum gantry crane.

Modeling and Dynamic Analysis of a Slider-Crank Mechanism With Flexible Coupler and Joint

1991 ◽  
Author(s):  
Junghsen Lieh ◽  
Imtiaz Haque
Keyword(s):  
Dynamic Analysis ◽  
Virtual Work ◽  
Equations Of Motion ◽  
Joint Stiffness ◽  
Mechanism Model ◽  
Double Frequency ◽  
Varying Coefficients ◽  
Matrix Expansion ◽  
Time Varying Coefficients ◽  
Crank Mechanism

Abstract Modeling and dynamic analysis of a slider-crank mechanism with flexible joint and coupler is presented. The equations of motion of the mechanism model are formulated using a virtual work multibody formalism and cast in terms of a minimum set of generalized coordinates through a Jacobian matrix expansion. Numerical results show the influence of time-varying coefficients on the mechanism dynamic behavior due to a repeated task. The results illustrate that the joint motion and coupler deformation are highly coupled. The joint response is dominated by double frequency of input, however, the coupler deformation is influenced by the same frequency as that of excitation. Increase in joint stiffness tends to decrease the variations in coupler deformation.

Nonlinear Marine Structures With Random Excitation

1988 ◽  
Vol 110 (3) ◽  
pp. 246-253 ◽  
Author(s):  
E. R. Jefferys
Keyword(s):  
Narrow Band ◽  
Equations Of Motion ◽  
Random Excitation ◽  
Wave Excitation ◽  
Offshore Structure ◽  
Chaotic Motions ◽  
Varying Coefficients ◽  
Excitation Time ◽  
Vessel Response ◽  
Time Varying Coefficients

Various important types of offshore structure contain significant nonlinearities or time-varying coefficients in their equations of motion. Well-known examples include tension leg platforms, free-hanging risers, single-buoy moorings, ships moored against fenders and vessels constrained by stiffening moorings. When subject to sinusoidal wave excitation, time domain mathematical models of these structures can display large subharmonic or chaotic motions. This paper shows that such behavior is often an artifact of the regularity of the excitation and is usually unlikely to present a significant problem in a random sea. Narrow-band vessel response can, however, generate near-harmonic motions to create conditions in which these instabilities may become important.

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.

Approximate Response of Beam-Type Resonant Biosensors

2018 ◽  
Author(s):  
Pezhman A. Hassanpour
Keyword(s):  
Differential Equation ◽  
Approximate Solution ◽  
Exponential Function ◽  
Multiple Scales ◽  
Method Of Multiple Scales ◽  
Impact Force ◽  
Equations Of Motion ◽  
Varying Coefficients ◽  
Time Varying Coefficients ◽  
The Impact

In this paper, the effect of absorption of antigens to the functionalized surface of a biosensor is modeled using a single degree-of-freedom mass-spring-damper system. The change in the mass of the system due to absorption is modeled with an exponential function. The governing equations of motion is derived considering the change in the mass of the system as well as the impact force due to absorption. It has been demonstrated that this equation is a linear second-order ordinary differential equation with time-varying coefficients. The solution of this differential equation is approximated by expanding the exponential function with a Taylor series and applying the method of multiple scales. The advantage of using the method of multiple scales to derive an approximate solution is in the insight it provides on the effect of each parameter on the response of the system. The free vibration response of the biosensor is derived using the approximate solution under different conditions, namely, with and without viscous damping, with and without considering the impact force, and for different binding rates.

Frequency-Modulation Input Shaping Control of Double-Pendulum Overhead Cranes

2013 ◽  
Vol 136 (2) ◽  
Author(s):  
Ziyad N. Masoud ◽  
Khaled A. Alhazza
Keyword(s):  
Frequency Modulation ◽  
Closed Loop ◽  
Single Mode ◽  
Mode Frequency ◽  
Input Shaping ◽  
Double Pendulum ◽  
Overhead Crane ◽  
Primary Input ◽  
Shaping Technique ◽  
Input Shaper

Traditionally, multimode input shaping controllers are tuned to systems' frequencies. This work suggests an alternative approach. A frequency-modulation (FM) input shaping technique is developed to tune the resonant frequencies of a system to a set of frequencies that can be eliminated by a single-mode primary input shaper. Most of the current input shaping techniques can be used as primary input shapers for the FM input shaping technique. Virtual feedback is used to modulate the closed-loop frequencies of a simulated double-pendulum model of an overhead crane to the point where the closed-loop second mode frequency becomes an odd-multiple of the closed-loop first mode frequency, which is the necessary condition for a satisfactory performance of most single-mode input shapers. The primary input shaper is based on the first mode frequency of the closed-loop system model. The input commands to the plant of the virtual feedback system are then used to drive the physical double-pendulum. Simulations results, using primary zero-vibration (ZV) and zero-vibration-derivative (ZVD) input shapers, are presented. The performance is validated experimentally on a scaled model of a double-pendulum overhead crane.

scholarly journals An Iterative Learning Control Technique for Point-to-Point Maneuvers Applied on an Overhead Crane

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Khaled A. Alhazza ◽  
Abdullah M. Hasan ◽  
Khaled A. Alghanim ◽  
Ziyad N. Masoud
Keyword(s):  
Iterative Learning Control ◽  
Equations Of Motion ◽  
Learning Control ◽  
Iterative Learning ◽  
Control Technique ◽  
Double Pendulum ◽  
Overhead Crane ◽  
Scaled Model ◽  
Low Sensitivity ◽  
Nonlinear Equations Of Motion

An iterative learning control (ILC) strategy is proposed, and implemented on simple pendulum and double pendulum models of an overhead crane undergoing simultaneous traveling and hoisting maneuvers. The approach is based on generating shaped commands using the full nonlinear equations of motion combined with the iterative learning control, to use as acceleration commands to the jib of the crane. These acceleration commands are tuned to eliminate residual oscillations in rest-to-rest maneuvers. The performance of the proposed strategy is tested using an experimental scaled model of an overhead crane with hoisting. The shaped command is derived analytically and validated experimentally. Results obtained showed that the proposed ILC control strategy is capable of eliminating travel and residual oscillations in simple and double pendulum models with hoisting. It is also shown, in all cases, that the proposed approach has a low sensitivity to the initial cable lengths.

Dynamics and Control of Bridge Cranes Transporting Distributed-Mass Payloads

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
Raymond Manning ◽  
Jeffrey Clement ◽  
Dooroo Kim ◽  
William Singhose
Keyword(s):  
Control Method ◽  
Single Mode ◽  
Input Shaping ◽  
Double Pendulum ◽  
Efficient Operation ◽  
Performance Improvements ◽  
Dynamics And Control ◽  
Damped Oscillation ◽  
And Control ◽  
Input Shaping Control

The large-amplitude and lightly-damped oscillation of crane payloads is detrimental to safe and efficient operation. The problem is further complicated when the payload creates a double-pendulum effect. Previous researches have shown that single-mode oscillations can be greatly reduced by properly shaping the inputs to the crane motors. This paper builds on previous developments by thoroughly describing the double-pendulum dynamic effects as a function of payload parameters and the crane configuration. Furthermore, an input-shaping control method is developed to suppress double-pendulum oscillations created by a payload with distributed-mass properties. Experiments performed on a 10-ton industrial bridge crane verify the effectiveness of the method. A critical aspect of the testing was human operator studies, wherein numerous operators utilized the input-shaping controller to perform manipulation tasks. The performance improvements provided by the input-shaping controller, as well as operator learning effects, are reported.

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