Input Shaping Control of Double-Pendulum Bridge Crane Oscillations

Author(s):  
William Singhose ◽  
Dooroo Kim ◽  
Michael Kenison

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.

Author(s):  
Raymond Manning ◽  
Jeffrey Clement ◽  
Dooroo Kim ◽  
William Singhose

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.


Author(s):  
Ehsan Maleki ◽  
William Singhose

Boom cranes are used for numerous material-handling and manufacturing processes in factories, shipyards, and construction sites. All cranes lift their payloads by hoisting them up using overhead suspension cables. Boom cranes move payloads by slewing their base about a vertical axis, luffing their boom in and out from the base, and changing the length of the suspension cable. These motions induce payload oscillation. The problem of payload oscillation becomes more challenging when the payload exhibits double-pendulum dynamics that produce two varying frequencies of oscillation. This paper studies the swing dynamics of such cranes. It also applies input shaping to reduce the two-mode oscillatory dynamics. Experiments confirm several of the interesting dynamic effects.


Author(s):  
Ziyad N. Masoud ◽  
Khaled A. Alhazza

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.


Author(s):  
Dooroo Kim ◽  
William Singhose

Oscillation of crane payloads makes it challenging to manipulate payloads quickly, accurately, and safely. The problem is compounded when the payload creates a double-pendulum effect. This paper evaluates an input-shaping control method for reducing double-pendulum oscillations. Human operator performance testing on a 10-ton industrial bridge crane is used to verify the effectiveness and robustness of the method. The tests required the operators to drive the crane numerous times over a period of eight days. Data from these experiments show that human operators perform manipulation tasks much faster and safer with the proposed control scheme. Furthermore, considerably less operator effort is required when input shaping is used to limit the oscillation. These experiments also show that significant learning occurred when operators did not have the aid of input shaping. However, the performance never approached that achieved with input shaping without any training. With input shaping enabled, only moderate learning occurred because operators were able to drive the crane near its theoretical limit during their first tests.


Author(s):  
Jisup Yoon ◽  
William Singhose ◽  
Joshua Vaughan ◽  
Gabriel Ramirez ◽  
Michael Kim ◽  
...  

The natural sway of crane payloads is detrimental to safe and efficient operation. Most crane control research has focused on oscillation induced by motion of the overhead trolley that is perpendicular to the vertical suspension cables. Little consideration has been given to bouncing oscillation in the hoist direction and pitching oscillation with respect to mass center of the payload. These dynamic effects arise in cases when the suspension cables are very long. These oscillations may interfere with the ability of the crane operators to accurately unload the payload at its desired position and orientation. This paper presents a method for generating shaped commands that suppress payload oscillations of bouncing and pitching. Theoretical models are initially used to develop and evaluate the input-shaping control algorithm. Then, experiments performed on a portable tower crane are used to demonstrate the improved response provided by the proposed approach.


Author(s):  
Minghui Xia ◽  
Xiaokai Wang ◽  
Qingxiang Wu ◽  
Lin Hua

In the assembly workshops of some heavy special equipment, the bridge cranes for payload lifting often needs to be located frequently. However, the locating position is often determined by the operator, which is random and results in significant payload oscillation and difficulties in trolley positioning. Furthermore, in practice, the bridge crane always exhibits more complicated double-pendulum dynamics compared with single-pendulum crane. To solve these problems, this paper establishes the double-pendulum model of bridge crane. Derived from the proportional-derivative (PD) control, the single closed-loop is designed based on the hook oscillation during acceleration and transporting; when locating, the double closed-loop is presented by utilizing the position and the hook oscillation. Combining the two control methods, a single and double closed-loop compound anti-sway control (SDCAC) method for the bridge crane is proposed. On this basis, to improve the performance of the SDCAC system, the sequential quadratic optimization (SQP) method is adopted to optimize PD parameters. Besides, a novel bumpless transfer control method is proposed to realize the smooth transition between the two control modes. Finally, the simulations and experiments are conducted. The results demonstrate the effectiveness of the proposed method.


Author(s):  
Ziyad N. Masoud ◽  
Khaled A. Alhazza ◽  
Mohammad A. Nazzal

Bulky rigid robotic arms require significantly large energy-consuming actuators. Lighter flexible robotic manipulators have many advantages over rigid manipulators in terms of cost, energy consumption, and speed. However, their structural flexibility compromises operation precision. This paper presents a multimode frequency-modulation input shaping control strategy for a flexible hanging beam performing rest-to-rest maneuvers. Frequency-modulation input shaping is used to produce shaped acceleration commands to the beam support. Model-based feedback is used to modulate the frequencies of the beam so that all higher mode frequencies become odd-integer multiples of the fundamental frequency of the feedback system. Single-mode input shaping techniques are implemented to eliminate vibrations in all modes of the model-based feedback system, and hence, the flexible beam. Numerical simulations are used to demonstrate the performance effectiveness of the proposed strategy.


Author(s):  
Khaled A. Alhazza

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.


Author(s):  
Joshua Vaughan ◽  
Paul Jurek ◽  
William Singhose

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.


Author(s):  
Robert Mar ◽  
Anurag Goyal ◽  
Vinh Nguyen ◽  
Tianle Yang ◽  
William Singhose

A control system combining input shaping and feedback is applied to a double-pendulum bridge crane subjected to external disturbances. The external disturbances represent naturally occurring forces, such as gusting winds. The proposed control method achieves fast point-to-point response similar to open-loop input-shaping control. It also minimizes transient deflections and disturbance-induced residual swing using the feedback control. Effects of parameters such as the mass ratio of the double-pendulum, suspension length ratio, and the traveled distance were studied via numerical simulation and hardware experiments. The controller effectively suppresses the disturbances and is robust to modeling uncertainties and task variations.


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