Crane Model Research Articles

Adaptive neural network hierarchical sliding mode control for six degrees of freedom overhead crane

AbstractThis paper presents an effective control method for three‐dimensional (3D) overhead cranes with six degrees of freedom (DOF). Two payload swings and an axial payload oscillation should be minimized besides driving the bridge, trolley, and hoisting drum to bring the payload to the desired position in space. First, a novel 3D‐6DOF crane model is developed, where the sixth degree of freedom is axial cargo oscillation that has never been considered in previous studies. A controller is then designed using the hierarchical sliding mode control method. Moreover, a radial basis function neural network (RBFNN) is used to approximate the system's unknown dynamic model accurately. According to the Lyapunov principle, a control law and an updated law for the neural network's weight matrices are designed to ensure the stability of the closed‐loop system. Simulation results on Matlab software show the proposed approach's effectiveness, such as smaller swing, minor axial oscillation, and precise position as desired.

Intelligent Control of industrial gantry crane model "3D Crane"

3D Crane represent Laboratory model of industrial gantry cranes which are widely used in industry. In this work, a dynamic model of 3D Crane is presented and tow artificial intelligence techniques were synthetized and applied to the model : Fuzzy Logic Control (FLC) and Adaptive Neural Fuzzy Inference System (ANFIS); the purpose of the control is the minimization of swing angles with continued reference trajectory in the three axes. A robustness test against external disturbance of the implemented controls was also apply. The results of the applied techniques are discussed.

Settling Time Optimization of a Critically Damped System with Input Shaping for Vibration Suppression Control

The input shaping technique is widely used as feedforward control for vibration suppression of flexible dynamic systems. The main disadvantage of the input shaping technique is the increasing system time response since the input shaper contains time delay parts. However, with the same reference input, the actuator effort in the case of using an input shaper is smaller than the one in the case without an input shaper. Thus, it is possible to decrease the system response time by designing the feedback controller to maximize the actuator effort. This paper proposes a design approach to design the Proportional-Derivative (PD) controller for position control of the actuator so that the settling time of the flexible system with input shaper is minimized. The actuator system with a PD controller is equivalent to a critically damped system, and the condition for the controller gains is established. In addition, the settling time and actuator effort with shaped step input are calculated. The controller gains can be determined by solving the settling time optimization problem with the actuator effort constraint. The effectiveness of the proposed approach is verified via experiments with an overhead crane model.

Neural network-based time optimal trajectory planning method for rotary cranes with obstacle avoidance

In this paper, an improved trajectory planning method is proposed, which can effectively avoid obstacles on the path and control the swing of the load during the transportation of a rotating crane within a certain range. The complex dynamics model of the rotary crane is first analyzed, and then the system constraint equations are established to ensure the transient performance during the boom motion. And an optimal time trajectory is obtained by the dichotomy method. Then, the trajectories for different obstacles, different starting positions and different final positions are generated by combining with a neural network method to achieve different control requirements. Finally, to confirm the superiority of the proposed method, it is verified by a hardware experimental platform.

Controller Design for Affine Nonlinear System Based on Constructing Optimization T–S Fuzzy Model and Disturbance Reconstruction

Affine nonlinear systems are special kinds of nonlinear systems, and they can represent many practical systems. Dealing with affine nonlinear system based on T–S fuzzy model has drawn much attention in the literature recently. In this article, a robust control method is proposed for affine nonlinear system with disturbance based on T–S fuzzy model. First, an optimization T–S fuzzy model is constructed focusing on optimizing the parameters of the weight functions by using differential evolution algorithm. Second, in order to reconstruct the disturbance, an interval observer is designed for the affine nonlinear system, and then a novelty disturbance reconstruction method based on the interval observer is developed. The disturbance reconstruction value can asymptotically approach the actual disturbance value, and furthermore, it decouples the control input. Third, by taking the optimization T–S fuzzy model as design model and by introducing the reconstruction of disturbance into controller, a feedback robust controller with disturbance compensation is designed to stabilize the affine nonlinear system. Finally, a simulation example of the crane model is given and some comparisons are provided to verify the effectiveness and show the advantages of the proposed method.

Nonlinear optimal control for the 4-DOF underactuated robotic tower crane

Tower cranes find wide use in construction works, in ports and in several loading and unloading procedures met in industry. A nonlinear optimal control approach is proposed for the dynamic model of the 4-DOF underactuated tower crane. The dynamic model of the robotic crane undergoes approximate linearization around a temporary operating point that is recomputed at each time-step of the control method. The linearization relies on Taylor series expansion and on the associated Jacobian matrices. For the linearized state-space model of the system a stabilizing optimal (H-infinity) feedback controller is designed. To compute the controller’s feedback gains an algebraic Riccati equation is repetitively solved at each iteration of the control algorithm. The stability properties of the control method are proven through Lyapunov analysis. The proposed control approach is advantageous because: (i) unlike the popular computed torque method for robotic manipulators, the new control approach is characterized by optimality and is also applicable when the number of control inputs is not equal to the robot’s number of DOFs, (ii) it achieves fast and accurate tracking of reference setpoints under minimal energy consumption by the robot’s actuators, (iii) unlike the popular Nonlinear Model Predictive Control method, the article’s nonlinear optimal control scheme is of proven global stability and convergence to the optimum.

Modeling and analysis technique of the hoisting system in the monorail crane

The monorail crane system (MCS) is a part of the ITER neutral beam remote handling system (NBRHS) in the neutral beam (NB) cell to lift and transport the components during their remote maintenance. The MCS is composed of four hoisting systems at each corner of the crane trolley, which are driven by two independent hoisting motors and gear chains. As the MCS works in a radiation controlled area where human worker access is strictly forbidden and there are lots of important components inside the NB cell, the structural and dynamic behaviors of the MCS are crucial that need to be verified. This paper describes a modeling and analysis technique of the hoisting system in the monorail crane. The hoisting system includes two drums and one balancer with a payload attached on it. The kinematic and dynamic model of the hoisting system is developed both for a non-extendable rope and for an extendable rope. Differential–Algebraic Equations (DAE) are constructed and its solution technique is described. Free body pendulum response is analyzed to verify the dynamic model and the solution technique. The dynamic equations with the realistic one quarter model of the hoisting unit are developed considering the rope flexibility. Synthesized seismic accelerogram is applied as the excitation forces. The time response of the balancer and the payload is calculated. The result shows that the dynamic model captures the six degree of freedom motion of the balancer and payload well during the seismic events. This methodology is applicable to develop a full multi body dynamic analysis model of the monorail crane.

Comparison of Extrainsensitive Input Shaping and Swing-Angle-Estimation-Based Slew Control Approaches for a Tower Crane

Tower cranes are needed to move heavy objects safely around construction sites. In tower cranes, payload oscillations are a typical problem that can cause safety issues, especially if the crane is not operated by an experienced user. Depending on the system, there are different causes for oscillations, e.g., inertial forces from the crane movement or external forces, such as weather conditions. Hence, the selected control law for input tracking plays an important role to limit the oscillatory motion and to help the crane operator to prevent unwanted operations. In this paper, we study the slew control of a tower crane application from the viewpoint of reducing payload oscillations. Two different approaches are studied: open-loop control based on extrainsensitive input shaping and closed-loop swing angle control, based on the estimation of the hoist cable angle. The proposed control approaches are validated by running the developed control program against a multibody mechanics simulator containing a model of a Liebherr tower crane. The studied control laws are also evaluated using an experimental setup, which consists of a two-axis manipulator, inverters, and a programmable logic controller in which the studied control methods are implemented. The results from the multibody dynamics simulations and from the experimental setup are presented and evaluated from the viewpoint of crane operation.

Optimisation of Dynamic Loads of Rope Systems of Lifting Mechanisms of Bridge Cranes During Cargo Handling

Relevance. In this study, considerable attention is devoted to the analysis of dynamic loads that occur in the rope systems of lifting mechanisms of overhead cranes during start-up and braking, and the reduction of these loads.Purpose. To identify the magnitude and nature of changes in dynamic loads in the elements of lifting mechanisms of bridge cranes, a comprehensive dynamic analysis of the lifting mechanism of the bridge crane and its elastic elements (rope systems) was performed.Methods. The dynamic analysis of the above mechanisms and systems was performed on well-grounded mathematical models of bridge-type cranes (single- and double-mass).Results. The analysis of the obtained calculations of mathematical models of the mechanism of lifting the load of bridge cranes demonstrated that the dynamic loads applied to the structural elements and drive mechanisms are oscillatory and comparable to static loads. The analysis of the obtained calculations of mathematical models of the mechanism of lifting the load of bridge cranes demonstrated that the dynamic loads applied to the structural elements and drive mechanisms are oscillatory and comparable to static loads. To minimise the integral functionals, the methods of classical calculus of variations, mathematical physics and differential equations were used to model the dynamics of loading processes of rope systems and drives of bridge cranes, and the terminal (initial and final conditions of movement of such systems) were considered, which allowed solving the optimisation problem unambiguouslyThus, to reduce dynamic loads in structural elements (in particular, in ropes) during transients in such lifting mechanisms of bridge cranes, it is proposed to perform optimisation of the modes of movement of their drive mechanisms. An essential place in such optimisation is occupied by the choice of the optimisation criterion. Among such criteria, integral optimisation criteria were used. As such integral optimisation criteria, the RMS values of the current loads in the elastic elements (ropes) of overhead travelling cranes have been used.Conclusions. Such integral criteria are integral functionalities that usually reflect undesirable properties of machines and their mechanisms, thus, they are subject to minimisation

An Enhanced Coupling Adaptive Sliding Mode Control Method for Casting Cranes Based on Radial Spring Damping

During the transference of a ladle by the casting crane, the antiswing control of the ladle is particularly difficult due to liquid sloshing, so we designed a model based on a radial spring damper. During the ladle swings, the centrifugal force causes the spring damper to move radially, thereby generating a Coriolis force that inhibits the sloshing of the liquid. In addition, a sloshing analysis of the liquid in the ladle is carried out, and a double-pendulum casting crane model based on viscous damping and radial spring damper is established. On the basis of this model, the Enhanced Coupled Adaptive Sliding Mode Control (ECASMC) method is proposed. By introducing an enhanced coupling variable and constructing a new coupling deviation signal, we enhance the relationship among state quantities. Then, a new type of sliding surface is designed based on the enhanced coupling deviation signal, and adaptive technology is used to adjust the sliding mode parameters, which enhances the system's robustness for system parameter variations and external disturbances. Using LaSalle's invariance principle and Lyapunov theorem, we prove that the casting crane system is asymptotically stable near the desired equilibrium point. The simulation results verify the effectiveness and superior control performance of the proposed method even in the presence of uncertainties.

인공지능 머신러닝을 이용한 카트-펜듈럼 이동제어 시스템 성형입력 설계

The tower crane is widely used in construction and transportation engineering. To improve working efficiency and safety, input shaping methods have been applied. Input shaping is a method of reducing residual vibration of flexible systems by convolving a sequence of impulses with unit step command. However, input shaping is based on the linear system theory in which its control performances are degraded, in case of nonlinearity and unmatched dynamics of the control systems. In this paper, a new optimal reference input shape design method based on minimizing cost function is suggested and applied, to a simple cart-pendulum system which is a simplified model of tower cranes. Since pendulum dynamics is nonlinear, analytic solution does not exist. To overcome this problem, in this paper, a machine learning approach is suggested to find optimal reference input shape for the cart position control. The feasibility of the proposed design method is verified through some simulation examples by using MatLab.

ANALYSIS ON ANTI-OVERTURNING STABILITY OF A TRUCK CRANE BASED ON ZERO MOMENT POINT THEORY

Truck crane stability has been a hot research issue. It is a conventional method used to calculate the moments equilibrium when analyzing stability. However, errors can occur because of the lack of dynamic simulation in conventional methods. Hence, to minimize errors, this study utilized the zero moment point (ZMP) theory to calculate the maximum lifting capacity of the truck crane considering the dynamic load, and proposed an anti-overturning detection method based on the theory. First, the model of the truck crane was established and the solution formula of ZMP was obtained. From the Lagrange equation, the dynamic model of payload oscillations was analyzed during crane operations. Second, the ZMP theory was used to analyze the stability of the truck crane and derive the maximum payload. Next, the experiment was conducted to measure the pressure of the four outriggers and their center of pressure (CoP) during hoisting, luffing, and slewing operations were calculated. Compared to stable movement, the CoP would vibrate irregularly, consequently reducing the lifting capacity of unstable motion. Finally, the anti-overturning detection method is proposed based on ZMP and CoP. Results demonstrate that the reduction of lifting capacity is caused by the dynamic load. The payload swing has a larger effect on the maximum lifting capacity than hoisting, luffing, and slewing motions. The maximum payload can decrease with the increase of the swing angle. The proposed method provides a correct judgment on the stability of the truck crane, which can accurately predict the overturning state of the crane and reduce the risk in the operation. Keywords: truck crane, overturning, zero moment point, center of pressure, stability

Study of adaptive control law of overhead crane using its model

Nowadays, cargo cranes are widely used in various areas of industries. Many of cranes use suspended load fastening, which is associated with load swinging during transportation. Load swinging is most often caused by acceleration or deceleration of the crane trolley, less often it occurs due to external disturbances, such as wind. One of the key directions of the development of this kind of cranes is the development of an automated control system that can dampen pendular oscillations of the load. At present, a considerable number of control systems have been developed, but most of them require preset adjustment of specific parameters of the transported load. The task of this study is to develop and debug a control algorithm using a model of an overhead crane of previously developed adaptive control law that can provide fine positioning and damping of load oscillations under the current parametric uncertainty. The study using the pilot plant will allow us to determine and analyze the features of the implementation of the control law before its application for industrial cranes. An adaptive control law is studied using the model of overhead crane under conditions of a current parametric uncertainty of the load and external disturbances. This control method is based on an adaptive control approach with an identifier and an implicit reference model using “simplified” adaptation conditions. A previously developed adaptive control law for an overhead crane is described. An experimental model of an overhead crane is described. An algorithm for adaptive control of an overhead crane model has been developed. The first experimental studies of the proposed control method have been carried out. They confirm its performance in real conditions. The results of experimental tests have shown the effectiveness of the adaptive control law. The system ensures fine motion of the load in a short period of time, dampens the pendular oscillations of the load during acceleration and deceleration of the trolley, as well as during external disturbances. The adaptive control law allows you to move the load to the designated position and dampen the pendular oscillations with minimal preset adjustment of the control system. Since the identification of parameters occurs at the current time, the changes of the parameters of the load and the length of suspension do not affect the quality of control.

Spatial and temporal predictions of whooping crane (Grus americana) habitat along the US Gulf Coast

AbstractThe challenge of conserving viable habitat while simultaneously predicting how land cover may geographically shift with future climate change has put pressure on ecologists and policy‐makers to develop near‐term (several years to a decade) ecological and geospatial predictions. This is particularly relevant for endangered species as ranges adjust to track a changing climate. The whooping crane is vulnerable to these changes, as the overwintering habitat of a small population is susceptible to climate impacts. This study mapped the historical spatial transformation of crane habitat in and around the Aransas National Wildlife Refuge. A time series of ecological niche models was developed to determine the biotic and abiotic factors correlated with crane presence and track how importance has changed over time. The results from the multitemporal models were used to predict areas along the US Gulf Coast where additional unoccupied habitat may be located for crane population expansion and model how the areas may degrade or change as sea levels rise through future climate change scenarios. Findings indicate that the percentage of emergent herbaceous wetland and water are the most important variables influencing crane presence. Sea level rise analysis indicates that potential habitat throughout the Texas–Louisiana Gulf Coast will be impacted considerably by climate change. The lack of large, continuous blocks of usable land cover could limit population expansion and future recovery efforts. However, the findings can help facilitate winter range expansion to accommodate the growing population by identifying additional areas to protect that could be used by the current wild population or experimental populations.

Modeling and observer-based robust controllers for telescopic truck cranes

Strict underactuation, complex structure, shape variation, and elasticity of machine elements cause many challenges in control of telescopic truck cranes. We develop a dynamic model of telescopic boom cranes considering flexibility and damping of load-carrying rope, viscoelasticity of boom-luff cylinder and extension cylinder. Modeling and control are constituted for the complex operation in which three motors including payload hoist, boom elevation, and boom expansion are simultaneously activated. We provide two observer-based robust controllers entitled second-order and fast-terminal sliding mode controls. These controllers work well even when the crane faces parametric variation and disturbance. The control system halves its sensors because of the performance of observer. We analyze and verify the effectiveness of modeling and controllers by applying to a Grove-TMS500 truck crane. Simulation results show the asymptotical convergence of actuated outputs and the stabilization of unactuated ones. The crane responses hold the robustness against winds and parametric uncertainties. The oscillations of crane outputs are due to elastic components such as handling ropes, two hydraulic cylinders for luffing and expanding the boom. The controllers well eliminate these undesirable oscillations.

Robust control with a novel 6-DOF dynamic model of indoor bridge crane for suppressing vertical vibration

Robust control with a novel 6-DOF dynamic model of indoor bridge crane for suppressing vertical vibration

Comparison of Analytical and Numerical Approach in Bridge Crane Solution

A crane bridge is a dominant component of all bridge crane. It is imperative to pay attention on its strength features and go through a strength analysis. The introductory part of this paper points out characteristics of a bridge crane, mainly a crane bridge and materials used to produce the crane bridge, namely S235 structural steel. The paper set out the strength analysis of the main girder of a single girder bridge crane model in the means of comparing analytical and numerical solutions. The calculations take into account the load of the main beam in its centre according to the standard STN 27 0103. The bridge crane model is designed for a 500 kg load carrying capacity. The numerical solu-tions are represented by finite element method (FEM) analysis in Ansys software. The intention is to determine the deformation of the main girder depending on the weight of a load and a hoist, to de-termine the maximum deflection and resulted bending stress. Furthermore, one of the purposes is to create the precise 3D CAD model of the main girder. The 3D CAD software Catia V5 was used to design the bridge crane model. The strength analysis of the main girder of IPE 100 profile was performed by the FEM analysis using the Ansys software and by analytical calculations. The results ob-tained by the computing software Ansys were only slightly smaller in comparison with the analytical calculations. Results obtained by Ansys can be considered as more accurate. It can be concluded, such the designed and strength-checked main girder can be in the future put into a production.

New results on sampled‐data output‐feedback control of linear parameter‐varying systems

AbstractThis article presents a novel sampled‐data static output‐feedback control technique for continuous‐time linear parameter‐varying (LPV) systems. Particularly, the input‐delay approach is introduced to map the sample‐and‐hold dynamics into the continuous‐time domain with delay in the states. This, together with a new parameter‐dependent Lyapunov–Krasovskii functional, results in a bounded real lemma for the underlying closed‐loop LPV systems. Furthermore, application of convex optimization techniques transforms the controller synthesis problem into the feasibility of a group of parameterized matrix inequalities. It is also shown that the convexification procedures allow for controller dependence on time‐varying parameters. Simulation studies are conducted on a case comparison and an overhead crane model to validate the efficacy and less conservatism of the result.

Eccentric-load dynamics and oscillation control of industrial cranes transporting heterogeneous loads

Industrial cranes transporting bulky loads are widely used in many engineering applications. However, heterogeneous loads give rise to eccentricity between the mass center and centroid of the load. Natural frequencies of the swing and twisting under eccentric-load mechanisms differ from those under uniform-load configurations. Therefore, load swing and twisting dynamic models that account for eccentricity are required to adequately understand and accurately control such cranes. Although significant work has been directed at the uniform-load dynamics of industrial cranes, little attention has been focused on the eccentric-load dynamics. This article presents a dynamic model of bridge cranes transporting heterogeneous loads. The frequency analyses of double-pendulum swing and twisting for eccentric loads is described. Additionally, a control method is designed using a simplified spherical pendulum with load-twisting dynamics and eccentric-load dynamics. Simulated and experimental results obtained from a small-scale bridge crane transporting a heterogeneous bar verify the utility of the analytical model and validate the effectiveness and robustness of the proposed control method.

Equivalent Rope Length-Based Trajectory Planning for Double Pendulum Bridge Cranes with Distributed Mass Payloads

The hoisting form in which the payload is hung on the hook by two rigging ropes is widely used in the industry, but it also results in the complex double pendulum dynamic of the bridge crane, making the anti-swing trajectory planning full of challenges. In this paper, based on the concept of the equivalent rope length, an equivalent single pendulum model of the double pendulum bridge crane with the distributed mass payload is established. On this basis, the particle swarm optimization algorithm is adopted to solve the equivalent rope length and calculate the parameters of the anti-swing velocity trajectory based on the phase plane method. To evaluate the effectiveness of the proposed method, experiments with a laboratory double pendulum bridge crane are conducted. Experimental results demonstrate that the residual oscillation angle of the payload of the proposed method is smaller than those of the existing methods, such as the trajectory planning without the equivalent rope length, input shaping and command smoothing.