Crane Motion Research Articles

The Impact of the FLC Controller’s Settings on the Precision of the Positioning of a Payload Transferred by a Mobile Crane

Abstract The paper presents a model of a control system of the slewing motion of a mobile crane in which the FLC controller was used, and then selected results of the numerical simulations of this model were presented. The influence of this controller’s settings on the precision with which the payload is positioned after it has been transferred to a target point for different angles of rotation of the jib, different lengths of the rope and different input signals of the controller was investigated.

Automating motion trajectory Of crane-lifted loads

Crane Lifting Path Planning (CLPP) is an important task, especially in congested construction sites. This activity becomes extremely complex since, as the project advances, new (and sometimes unpredicted) constraints may occur. These constraints force lift engineers to explore the possibility of alternative paths for the objects still to be moved. Under severe time constraints, manual analysis of such paths is practically impossible, which makes it necessary to rely on computer implementations in order to avoid project delays. From a mathematical standpoint, if the crane payload trajectory is to be defined analytically, the polar coordinate system,(r, θ), is naturally the most suitable. As a result, this paper proposes an algorithm for CLPP in which the path is represented as a piece-wise continuous function where each portion is defined either by constant radius (rotation of the load) or a constant angle (translation of the load). In other words, rather than forcing a crane to adapt to un-natural rectilinear trajectories as obtained by traditional path searching procedures, it is the trajectory that is adapted to the crane motion. In fact, even though (mathematically) a precise balance between the rates of rotation and translation of the jib (or boom) will make the payload follow any continuous path (regardless of its complexity), the coupling between the rotations and translations increases the difficulty of the lifting activity. However, a crane lifting path in which these motions are uncoupled will lead to less stringent requirements in terms of controlling the balance between rotations and translations.

The Motion Characteristics and Pressure Analysis of Drive System of Monorail Crane

This article mainly on monorail crane motion characteristics of three different kinds of drive systems and pressure analysis of I-steel. The motion characteristics figure of hydraulic step cylinder drive system, friction wheel drive system, rack-and-pinion drive system are done by Solidworks Motion module. The I-steel pressure analysis of different drive systems is done by the Ansys Workbench module. By analyzing and comparing the figures, the rack-and-pinion drive system has a superior property in both motion characteristics and pressure of I-steel.

Anti-Sway Control Schemes of a Boom Crane Using Command Shaping Techniques

This paper presents investigations into the applications and performance of command shaping techniques for control of payload sway of a boom crane based on filtering and the input shaping technique. The mathematical dynamic model describing the motion of the boom crane is developed using the Lagrange-Euler's equation. The dynamic characteristics of the system are studied and analysed using the Matlab Simulink in time and frequency domains. Command shaping techniques based on filtering and the input shaping techniques are then developed and used to control the payload sway of the boom crane. The performance of the control techniques are studied in terms of the level of sway reduction, time response and robustness. Finally, a comparative assessment of the effectiveness of the control schemes for sway control of a boom crane is presented and discussed.

Spherical Pendulum Small Oscillations for Slewing Crane Motion

The present paper focuses on the Lagrange mechanics-based description of small oscillations of a spherical pendulum with a uniformly rotating suspension center. The analytical solution of the natural frequencies' problem has been derived for the case of uniform rotation of a crane boom. The payload paths have been found in the inertial reference frame fixed on earth and in the noninertial reference frame, which is connected with the rotating crane boom. The numerical amplitude-frequency characteristics of the relative payload motion have been found. The mechanical interpretation of the terms in Lagrange equations has been outlined. The analytical expression and numerical estimation for cable tension force have been proposed. The numerical computational results, which correlate very accurately with the experimental observations, have been shown.

Trolley and Hoisting Motion Planning of Cranes Using Linear Programming

A new numerical method to obtain a suboptimal solution of the minimum-time anti-swing motion planning problem for cranes based on the use of linear programming is proposed. Both the trolley and the hoisting motions are the problem unknowns. A classical kinematical nonlinear model for which the trolley acceleration and the hoisting speed are the control variables is used. The crane motion equations are discretized in time assuming that the control variables are piecewise constant. Inequality constraints on state and control variables are included in order to represent physical bounds associated to the electromechanical driving system. Equality constraints are added in to represent the requirement that both the load and the trolley be at rest at the end points of the trolley path. The proposed algorithm consists in the repetition of two steps: (i) an approximation of the hoisting motion is fixed and a corresponding suboptimal trolley motion is computed; (ii) first-order corrections on both the hoisting and the trolley motions are computed based on a linearized model of the system. In spite of the nonlinear dynamics, both steps are reduced to solving Linear Programming problems. A convergence proof of the algorithm is presented. The ease of both the formulation and the solution of the problem contrasts with the traditional two-point boundary value problem associated to the Pontryagin’s minimum principle.

Simple rotary crane dynamics modeling and open-loop control for residual load sway suppression by only horizontal boom motion

To suppress two-dimensional load sway caused by the horizontal boom motion of a rotary crane, both horizontal and vertical boom motions are generally used. However, it would be more energy efficient and safer if a control scheme using only horizontal boom motion could be developed, eliminating the need for any boom vertical motion. In addition, if we can suppress load sway without the need to measure it, cost reduction of sensors can be achieved. Furthermore, the use of simple velocity trajectory patterns such as a trapezoidal velocity pattern and an S-curve acceleration/deceleration pattern, which are widely used in industrial automation systems, may provide cost-effective implementation of controllers. This paper presents a simple model of rotary crane dynamics that includes only significant centrifugal and Coriolis force terms. This simple model allows analytical solutions of the differential equations of the model to be derived. Thus, S-curve trajectory that considers residual vibration suppression without sensing it, using only horizontal boom motion, can be generated by solving only algebraic equations numerically. The effectiveness of the proposed method is demonstrated by numerical simulations and experimental results.

Анализ динамики механизма передвижения мостового крана с частотным управлением привода

Анализ динамики механизма передвижения мостового крана с частотным управлением привода

Simmechanics Visualization of Experimental Model Overhead Crane, Its Linearization And Rerence Tracking-Lqr Control

Overhead Crane experimental model using Simmechanic Visualization is presented for the robust antisway LQR control. First, 1D translational motion of overhead crane is designed with exact lab model measurements and features. Second, linear least square system identification with 7 past inputs/outputs is applied on collected simulation data to produce more predicted models. Third, minimize root mean square error and identified the best fit model with lowest RMSE. Finally, Linear Quadratic Regulator (LQR) and Reference tracking with pre-compensator have been implemented to minimize load swing and perform fast track on trolley positioning.

Partial feedback linearization control of a three-dimensional overhead crane

Based on partial feedback linearization, an improved nonlinear controller is analyzed and designed for the three-dimensional motion of an overhead crane. Three control inputs composed of bridge moving, trolley travelling, and cargo hoisting forces are used to drive five state variables consisting of bridge motion, trolley movement, cargo hoisting displacement, and two cargo swing angles. The control scheme is constituted by linearly combining two components that are separately obtained from the nonlinear feedback of actuated and un-actuated states. To verify the quality of the control process, both numerical simulation and experimental study are carried out. The proposed controller asymptotically stabilizes all system states.

Tip-Over Stability Analysis of Mobile Boom Cranes With Swinging Payloads

Mobile boom cranes are used throughout the world to perform important and dangerous manipulation tasks. The usefulness of these cranes is greatly improved if they can utilize their mobile base when they lift and transfer a payload. However, crane motion induces payload swing. The tip-over stability is degraded by the payload oscillations. This paper presents a process for conducting a stability analysis of such cranes. As a first step, a static stability analysis is conducted to provide basic insights into the effects of the payload weight and crane configuration. Then, a semi-dynamic method is used to account for payload swing. The results of a full-dynamic stability analysis using a multibody simulation of a boom crane are then compared to the outcomes of the simpler approaches. The comparison reveals that the simple semi-dynamic analysis provides good approximations for the tip-over stability properties. The results of the stability analyses are verified by experiments. The analysis in this paper provides useful guidance for the practical tip-over stability analysis of mobile boom cranes and motivates the need to control payload oscillation.

Non-Collision Path Planning of a Payload in Crane Operating Space

The problem of ensuring the safe and efficient cranes operations in automated manufacturing processes involves the automation of the operating workspace identification, non-collision and time-optimal path planning, and real-time following a payload along the determined path by crane motion mechanisms with expected precision. The paper describes the stereo vision based system used for identification of workspace of the laboratory scaled overhead travelling crane. The time-optimal trajectory of a payload is determined by using the A-star graph searching algorithm, and next real-time trucking by PLC-based crane control system.

Simulated productivity of one- and two-armed tree planting machines

To increase mechanized planting, planting machine productivity must increase in order to improve cost-efficiency. To determine if excavators with two crane arms could potentially help to increase planting machine productivity under Nordic clearcut conditions, we modelled one-armed and semi-automated two-armed excavators with one- and two-headed planting devices. Using a recently developed tool for discrete-event simulation, these machine models then mounded and planted seedlings on terrain models with moraine soil having various frequencies of obstacles (stumps, roots and stones). Compared to if the two heads were mounted pairwise on only one arm, the results showed that productivity did not increase if two planting heads were attached individually to two separate crane arms. But productivity did increase if the planting machine had four planting heads mounted pairwise on two separate arms. However, despite assuming automated mounding and crane motion between planting spots, the two-armed, four-headed model never achieved high enough productivity levels to make it more cost-efficient than one-armed machines. The simulations illustrate that our terrain models generate realistic root architecture and boulder content distributions in moraine soil, while our machine models functionally describe mechanized planting work. Based on our assumptions, we conclude that further development work on two-armed excavator-based planting machines for Nordic clearcut conditions is not warranted. Our simulations reveal that increasing the number of planting heads per crane arm rather than number of crane arms per base machine offers the greatest potential to raise the productivity of intermittently advancing planting machines.

Proposal of a Simple Trajectory Generation Method Using Power Series (Its Application to Residual Vibration Suppression of Mechanical Systems)

As described in this paper, we specifically examine a point-to-point (PTP) motion task of mechanical systems and present a simple trajectory generation method for suppressing the residual vibrations. In the proposed method, a PTP motion trajectory is generated by giving the output of a power series of time as the input of a cycloidal function. The generated trajectory depends on the coefficients of the power series. To cancel unwanted vibration, the coefficients are tuned by metaheuristic algorithms. The residual vibrations of mechanical systems can be suppressed by driving along the obtained trajectory, that is, the proposed vibration control method is a feedforward control technique. We deal with the PTP motion of an overhead crane with load hoisting, and demonstrate the effectiveness of the proposed method through numerical simulations. Furthermore, the proposed method is also applied to simultaneously minimize the residual vibration and the operating energy in a single-link flexible manipulator. The results obtained from this application consolidate the validity of our approach.

C14 機械システムの残留振動抑制を目的とした簡便な軌道計画法の提案(M-OS7-1:精密・情報・産業機器の制御,M-OS7 精密・情報・産業機器の制御,「海を越え,国を越え,世代を超えて!」)

As described in this paper, we specifically examine a point-to-point (PTP) motion task of mechanical systems and present a simple trajectory generation method for suppressing the residual vibrations. In the proposed method, a PTP motion trajectory is generated by giving the output of a power series of time as the input of a cycloidal function. The generated trajectory depends on the coefficients of the power series. To cancel unwanted vibration, the coefficients are tuned by metaheuristic algorithms. The residual vibrations of mechanical systems can be suppressed by driving along the obtained trajectory, that is, the proposed vibration control method is a feedforward control technique. We deal with the PTP motion of an overhead crane with load hoisting, and demonstrate the effectiveness of the proposed method through numerical simulations. Furthermore, the proposed method is also applied to simultaneously minimize the residual vibration and the operating energy in a single-link flexible manipulator. The results obtained from this application consolidate the validity of our approach.

Motion Planning Method for Two Stacker Cranes in an Automated Storage and Retrieval System

In this paper, a motion planning method for two stacker cranes in an Automated Storage and Retrieval System (AS/RS) is proposed. For the cranes to operate cooperatively, they must perform tasks while avoiding collisions. In addition, the requirements, which include fast operation and short calculation time, must be satisfied, along with a specific mechanical constraint on the motion of the stacker cranes. For these problems, an approach is proposed in which a motion is generated on two levels. On the first, collision is avoided by using constraint on trajectories. A trajectory generated on this level ensures the shortest travel time. If a collision cannot be avoided on the first level, the system shifts to the second, in which heuristics are used for collision avoidance. The proposal is for highspeed heuristics based on a binary search. The effectiveness of the proposed algorithm is shown through simulations. The simulation results indicate that, in a layout of 60 racks in the horizontal direction and 10 in the vertical direction under standard task conditions, the method has an efficiency of 1.91 with respect to a single crane system and 1.66 seconds for the motion planning of one task when a computer with a 3.0 GHz CPU is used.

The use of virtual prototyping to rehearse the sequence of construction work involving mobile cranes

PurposeRehearsing practical site operations is without doubt one of the most effective methods for minimising planning mistakes, because of the learning that takes place during the rehearsal activity. However, real rehearsal is not a practical solution for on‐site construction activities, as it not only involves a considerable amount of cost but can also have adverse environmental implications. One approach to overcoming this is by the use of virtual rehearsals. The purpose of this paper is to investigate an approach to simulation of the motion of cranes in order to test the feasibility of associated construction sequencing and generate construction schedules for review and visualisation.Design/methodology/approachThe paper describes a system involving two technologies, virtual prototyping (VP) and four‐dimensional (4D) simulation, to assist construction planners in testing the sequence of construction activities when mobile cranes are involved. The system consists of five modules, comprising input, database, equipment, process and output, and is capable of detecting potential collisions. A real‐world trial is described in which the system was tested and validated.FindingsFeedback from the planners involved in the trial indicated that they found the system to be useful in its present form and that they would welcome its further development into a fully automated platform for validating construction sequencing decisions.Research limitations/implicationsThe tool has the potential to provide a cost‐effective means of improving construction planning. However, it is limited at present to the specific case of crane movement under special consideration.Originality/valueThis paper presents a large‐scale, real life case of applying VP technology in planning construction processes and activities.

Minimum‐time anti‐swing motion planning of cranes using linear programming

SUMMARYA novel method to solve the minimum‐time anti‐swing motion planning problem for cranes based on the use of linear programming is proposed. It is shown that its solution can be obtained by solving a sequence of fixed‐time maximum‐range linear programming problems. A convergence proof is presented. A classical kinematical model for which the trolley acceleration is the control variable is used. The crane motion equations are discretized in time assuming that the control variable is piecewise constant. Inequality constraints on both trolley speed and acceleration are included to represent physical bounds associated to the electromechanical driving system. The load and the trolley are required to be at rest both at the initial and at the final times. The load cable length as a function of time is assumed given. The ease of both the formulation and the solution of the problem is in contrast with the traditional two‐point boundary value problem associated to the Pontryagin's minimum principle. Copyright © 2012 John Wiley & Sons, Ltd.

Improving lifting motion planning and re-planning of cranes with consideration for safety and efficiency

Safe and efficient operation of cranes requires not only good planning, but also sufficient and appropriate support in real time. Due to the dynamic nature of construction sites, unexpected changes in site layout may create new obstacles for the crane that can result in collisions and accidents. Previous research on construction equipment motion planning focuses on off-line support, which considers static environment or predictable obstacles. These plans may not fit the reality when the environment has any change. In this case on-site safety and efficiency can be affected. In this research, a motion planning algorithm is proposed to efficiently generate safe and smooth paths for crane motions while taking into account engineering constraints and the path quality. Path smoothness is taken into account to provide a realistic path for cranes and to reduce unnecessary movements. A dynamic motion planning algorithm is proposed to ensure safety during the execution stage by quickly re-planning and avoiding collisions. In addition, an anytime algorithm is proposed to search for better solutions during a given time period by improving path smoothness and by reducing path execution time. The proposed algorithms are compared with other available algorithms to evaluate their performance in terms of planning and re-planning time and the cost of the path. Based on the literature review, this is the first time that dual-tree RRT algorithms have been applied to crane motion planning.

1P1-I10 LMIによる固有振動数変動を考慮した旋回クレーンのロバスト制御(生産システム・生産機器メカトロニクス)

Because natural frequency of the rope-load oscillation system affects the stability and performance of the crane control system, the controller design should consider robustness with respect to rope length. If the control system considers the effect of rope length variance, the crane's motion can be controlled without a sensor system for measuring it. This paper presents a control method based on linear matrix inequality (LMI) optimization for achieving robustness with respect to rope length variance. Simulation results demonstrate the effectiveness of the proposed method.