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.

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.

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.

A Frequency-Modulation Command-Shaping Strategy for Multi-Mode Systems

2013 ◽  
Author(s):  
Ziyad N. Masoud ◽  
Khaled A. Alhazza
Keyword(s):  
Frequency Modulation ◽  
Closed Loop ◽  
Single Mode ◽  
Mode Frequency ◽  
Loop System ◽  
Loop Model ◽  
Closed Loop System ◽  
Command Shaping ◽  
Scaled Models ◽  
Multi Mode

Single-mode shaped commands can be implemented for oscillations control of multi-mode systems provided that all frequencies of the system are odd-multiples of the shaped command frequency. This criterion is utilized in this work to develop a command shaping strategy for multi-mode systems. A frequency-modulation command shaper is derived based on the use of a single-mode command-shaping technique. The proposed strategy is based on deriving a closed-loop model of a multi-mode system with its modal frequencies modulated so that higher mode frequencies are odd-multiples of the first mode frequency. A single-mode double-step primary command-shaper with a design frequency equal to the first mode frequency of the closed-loop system is then used. The input command to the plant of the closed-loop system is used as shaped commands for the multi-mode system. Numerical simulations are used to demonstrate the performance of the proposed strategy along with experiments on scaled models of a triple, quadruple, and quintuple-pendulums.

A Hybrid Command-Shaping Control System for Highly Accelerated Double-Pendulum Gantry Cranes

2009 ◽  
Author(s):  
Ziyad N. Masoud ◽  
Khalid A. Alhazza ◽  
Majed A. Majeed ◽  
Eiyad A. Abu-Nada
Keyword(s):  
Control Systems ◽  
Degrees Of Freedom ◽  
Gantry Crane ◽  
System Control ◽  
Double Pendulum ◽  
Pendulum System ◽  
Command Shaping ◽  
Simple Pendulum ◽  
Time Optimal ◽  
Gantry Cranes

A gantry cranes is generally modeled as a simple-pendulum with a point mass attached to the end of a massless rigid link. Numerous control systems have been developed to reduce payload oscillations in order to improve safety and positioning accuracy of crane operations. However, large-size payloads transforms the crane model from a simple-pendulum system to a double-pendulum system. Control systems that consider only one mode of oscillations of a double-pendulum may excite large oscillations in the other mode. In multi-degrees-of-freedom systems, command-shaping controllers designed for the first mode may eliminate oscillations of higher modes provided that their frequencies are odd integer multiples of the first mode frequency. In this work, a hybrid command-shaping controller is designed to generate acceleration commands to suppress travel and residual oscillations of a highly accelerated double-pendulum gantry crane. It is shown that the suggested hybrid command-shaper is capable of minimizing oscillations of both modes of a scaled experimental double-pendulum model of a gantry crane. Results show that the hybrid command-shaper produces a reduction of 95% in residual oscillations in both modes of the double-pendulum over the time-optimal rigid-body commands.

scholarly journals Trapping of waves by a submerged elliptical torus

2002 ◽  
Vol 456 ◽  
pp. 277-293 ◽  
Author(s):  
M. McIVER ◽  
R. PORTER
Keyword(s):  
Fluid Velocity ◽  
Three Dimensional ◽  
Mode Frequency ◽  
The Body ◽  
Necessary Condition ◽  
Numerical Evidence ◽  
Side Condition ◽  
Trapped Mode ◽  
Specific Geometry ◽  
The Time Domain

An investigation is made into the trapping of surface gravity waves by totally submerged three-dimensional obstacles and strong numerical evidence of the existence of trapped modes is presented. The specific geometry considered is a submerged elliptical torus. The depth of submergence of the torus and the aspect ratio of its cross-section are held fixed and a search for a trapped mode is made in the parameter space formed by varying the radius of the torus and the frequency. A plane wave approximation to the location of the mode in this space is derived and an integral equation and a side condition for the exact trapped mode are obtained. Each of these conditions is satisfied on a different line in the plane and the point at which the lines cross corresponds to a trapped mode. Although it is not possible to locate this point exactly, because of numerical error, existence of the mode may be inferred with confidence as small changes in the numerical results do not alter the fact that the lines cross.If the torus makes small vertical oscillations, it is customary to try to express the fluid velocity as the gradient of the so-called heave potential, which is assumed to have the same time dependence as the body oscillations. A necessary condition for the existence of this potential at the trapped mode frequency is derived and numerical evidence is cited which shows that this condition is not satisfied for an elliptical torus. Calculations of the heave potential for such a torus are made over a range of frequencies, and it is shown that the force coefficients behave in a singular fashion in the vicinity of the trapped mode frequency. An analysis of the time domain problem for a torus which is forced to make small vertical oscillations at the trapped mode frequency shows that the potential contains a term which represents a growing oscillation.

scholarly journals Closed-loop ring resonator topology for bandpass filter applications

2020 ◽  
Vol 17 (3) ◽  
pp. 1422
Author(s):  
Norfishah Ab Wahab ◽  
M. N. Md Tan ◽  
M. N. Hushim
Keyword(s):  
Transmission Lines ◽  
Closed Loop ◽  
Bandpass Filter ◽  
Ring Resonator ◽  
Single Mode ◽  
Ring Structure ◽  
Transmission Zeros ◽  
Quarter Wavelength ◽  
Coupled Lines ◽  
Loop Ring

<p class="Pa41">This paper presents a single mode pseudo-elliptic bandpass resonator based on closed-loop ring topology. The resonator is built from six quarter wavelength transmission lines to form a square closed-loop ring structure. This structure creates transmission zeros at the lower and upper sidebands so that high selectivity bandpass filter response is achieved. The advantage of this topology is that the design is less complex since no perturbation is needed on the ring lines for creation of transmission zeros. Higher-order filters can be constructed by introducing quarter-wavelength coupled-lines, coupled at both input and output of the closed-loop ring resonator. For proof of concept, the filters are designed at 10 GHz up to 3<sup>rd</sup> order, simulated using full-wave electromagnetic simulator on microstrip substrate, <em>FR-4</em> with characteristics given as <em>Ԑr </em>= 4.70, <em>h </em>= 1.499 mm and <em>tan δ </em>= 0.012.  The filters are simulated and responses are found to be agreeable with the proposed idea.</p>

scholarly journals Modeling and energy-based sway reduction control for tower crane systems with double-pendulum and spherical-pendulum effects

2019 ◽  
Vol 53 (1-2) ◽  
pp. 141-150 ◽  
Author(s):  
Menghua Zhang ◽  
Yongfeng Zhang ◽  
Bing Ji ◽  
Changhui Ma ◽  
Xingong Cheng
Keyword(s):  
Closed Loop ◽  
Double Pendulum ◽  
Control Methods ◽  
Spherical Pendulum ◽  
Closed Loop System ◽  
Tower Crane ◽  
Lyapunov Techniques ◽  
Payload Mass ◽  
System States ◽  
Invariance Theorem

As typical underactuated systems, tower crane systems present complicated nonlinear dynamics. For simplicity, the payload swing is traditionally modeled as a single-pendulum in existing works. Actually, when the hook mass is close to the payload mass, or the size of the payload is large, a tower crane may exhibit double-pendulum effects. In addition, existing control methods assume that the hook and the payload only swing in a plane. To tackle the aforementioned practical problems, we establish the dynamical model of the tower cranes with double-pendulum and spherical-pendulum effects. Then, on this basis, an energy-based controller is designed and analyzed using the established dynamic model. To further obtain rapid hook and payload swing suppression and elimination, the swing part is introduced to the energy-based controller. Lyapunov techniques and LaSalle’s invariance theorem are provided to demonstrate the asymptotic stability of the closed-loop system and the convergence of the system states. Simulation results are illustrated to verify the correctness and effectiveness of the designed controller.

DYNAMIC MODELLING OF A DOUBLE-PENDULUM GANTRY CRANE SYSTEM INCORPORATING PAYLOAD

2011 ◽  
Author(s):  
R. M. T. Raja Ismail ◽  
M. A. Ahmad ◽  
M. S. Ramli ◽  
R. Ishak ◽  
M. A. Zawawi ◽  
...  
Keyword(s):  
Dynamic Modelling ◽  
Gantry Crane ◽  
Double Pendulum
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