A new approach for the anti-swing control of overhead cranes with high-speed load hoisting

The objective of this study is to design a new anti-swing control scheme for overhead cranes, the performance of which equals or possibly surpasses the performance of a skilled crane operator. In this study, the anti-swing control problem is solved as a trajectory-tracking control problem. An anti-swing trajectory control scheme is designed based on the Lyapunov stability theorem, and then extended to an adaptive scheme to cope with parametric uncertainties, in which sufficient damping of load swing is achieved by modifying the reference trajectory of the trolley. The proposed control consists of a feed forward control and a non-linear PID control with gravity compensation, which guarantees asymptotic stability while keeping all internal signals bounded. The proposed control, allowing high-speed load hoisting, also guarantees accurate control of trolley position and rope length with optimum damping. In summary, the proposed control realizes a typical crane operation in practice, maintains its control performance in the presence of parametric uncertainties, and has a simple structure for easy implementation and gain tuning. The performance of the proposed control is shown with computer simulations.     

小车吊重系统摆振动力学模型及仿真

认识和掌握吊重摆振的动力学特性,是研究起重机防摇控制方案的前提条件.为了准确分析吊重摆振的动力学规律和影响因素,采用理论分析和动态仿真的方式对吊重摆振特性进行了研究.文中根据起重机小车-吊重系统的三维动力学模型建立了吊重摆振的二自由度摆角动力学模型,通过线性简化从模型中找出了影响摆角大小的主要因素--吊重绳长和运行加(减)速度,并以此动力学模型进行了起重机在多种工况下的动态仿真.通过仿真分析得到了小车加速度和吊重绳长对吊重摆振角度、频率和摆角速度的影响规律.     

Nonlinear Anti-swing Control of Underactuated Tower Crane Based on Improved Energy Function

The control system of tower crane exhibits strong nonlinearity in the process of control execution, which is prone to the problems of inaccurate positioning control of the payload and difficult anti-swing control. Aiming at the problems, this paper proposes a control law based on improved energy coupling analysis for suppressing the payload swing in the tower cranes. A three-dimensional dynamic model of tower crane system with considering friction is established, and an improved energy coupling signal is designed. The coupling relationship of trolley movement and payload swing, jib rotation and payload swing are considered, then a nonlinear anti-swing controller is established in order to reduce the swing. The closed-loop stability of the system with the controller is verified by the Lyapunov method and LaSalle invariance principle, simulations and experimental analyses are performed to verify the controller performance. The control performance of the controller is compared with other classic and typical current control methods, and the proposed controller outperformed other controllers. The anti-swing controller proposed in this paper has accurate positioning, and can achieve precise control when the payload is transported, reaching the set target position in a little time and eliminating residual swing angle. Meanwhile the proposed controller has a good control robustness, which can restore stability in around a very short time when the rope length and payload mass of the system’s inherent property are changed and external interference is added. In addition, when different target position parameters are uncertain, the proposed control law has good robust performance.

     

A new design approach for the anti-swing trajectory control of overhead cranes with high-speed hoisting

This paper proposes a new approach for the design of anti-swing control of overhead cranes. An anti-swing trajectory control scheme is designed based on the trolley and load-hoisting dynamics, and then extended to an adaptive scheme. The load-swing dynamics is controlled by employing a sliding surface that couples the load-swing dynamics with trolley motion. The number of degrees of freedom of the trolley and load-hoisting dynamics is the same as that of the control inputs; therefore, the control problem is reduced to finding a coupled sliding surface that stabilizes the crane control system, based on the load-swing dynamics. In this study, the Lyapunov stability theorem is used as a mathematical design tool. The proposed control guarantees asymptotic stability of the anti-swing trajectory control while keeping all internal signals bounded. The coupled sliding surface allows a direct control of the damping of load swing. In addition, the proposed control provides clear gain-tuning criteria for easy application. Finally, the proposed control realizes an anti-swing control along a typical anti-swing trajectory in practice, with high-speed load hoisting. The validity of the theoretical results is shown by computer simulation.     

二维桥式起重机的滑模控制

基于滑模控制理论,研究二维桥式起重机的控制器设计问题.首先,考虑小车端受到外界干扰的情况以及利用一些等价变换,得到一个四阶桥式起重机动力学模型;然后,根据得到的动力学方程,分别设计一种比例微分滑模控制器和一种比例微分积分滑模控制器,进而通过构造李雅普诺夫函数的方法证明两种控制器下滑模面的可达性和系统的稳定性;最后,设计1组对比仿真实验和1组在自制的桥式起重机实验平台上的验证性实验.实验结果表明,所设计的两种滑模控制器均可以使桥式起重机达到给定的控制目标.     

Dynamics analysis and fuzzy anti-swing control design of overhead crane system based on Riccati discrete time transfer matrix method

This paper describes an efficient method called Riccati discrete time transfer matrix method of multibody system (MS-RDTTMM) for studying the dynamic modeling and anti-swing control design of a two-dimensional overhead crane system, which consists of a trolley, rope, load, and control subsystem. Regarding the rope as a series of rigid segments connected by hinges, a multibody model of the overhead crane system can be developed easily by using MS-RDTTMM. Then three separate fuzzy logic controllers are designed for positioning and anti-swing control. For improving the performance of the predesigned fuzzy control system, the genetic algorithm based on MS-RDTTMM is presented offline to tune the initial control parameters. Using the recursive transfer formula to describe the system dynamics, instead of the global dynamics equation in ordinary dynamics methods, the matrices involved in this method are always very small, and the computational cost of the dynamic analysis and control system optimization can be greatly reduced. The numerical verification is carried out to show the computational efficiency, numerical stability, and control performance of the proposed method.     

Combined control with sliding mode and partial feedback linearization for 3D overhead cranes

A 3D overhead crane is an underactuated system consisting of five outputs: trolley position, bridge translation, cable length, and two cargo swings. These outputs are controlled by three actuators for cargo hoisting, trolley motion, and bridge traveling. This study proposes the use of a nonlinear controller that performs five tasks concurrently: cargo hoisting, trolley tracking, bridge motion, payload vibration suppression during transport, and cargo swing elimination at the destination. The proposed algorithm is combined with two control components: (i) partial feedback linearization, which is a precursor to controller design, to suppress cargo vibration; and (ii) sliding mode method, which provides robust control in lifting the payload and driving trolley and bridge motions against model imprecision and uncertainty. These two control mechanisms are successfully merged into a combined controller because the kinematic relationships between the state variables are made apparent in the system dynamics. Simulation and experimental results show that the proposed controller asymptotically stabilizes all system responses.Copyright © 2013 John Wiley & Sons, Ltd.     

A pure neural network controller for double‐pendulum crane anti‐sway control: Based on Lyapunov stability theory

Crane systems have been widely applied in logistics due to their efficiency of transportation. The parameters of a crane system may vary from each transport, therefore the anti‐sway controller should be designed to be insensitive to the variation of system parameters. In this paper, we focus on pure neural network adaptive tracking controller design issue that does not require the parameters of crane systems, i.e. the trolley mass, the payload mass, the cable lengths, and etc. The proposed neural network controller only requires the output feedback signals of the trolley, i.e. the position and the velocity, which means no sway measuring equipment is needed. The Lyapunov method is utilized to design the weights update law of neural network, and the robustness of the proposed controller is proved by the Lyapunov stability theory. The results of numerical simulations show that the proposed neural network controller has excellent performance of trolley position tracking and payload anti‐sway controlling.     

起重机吊重系统状态观测器设计与仿真

针对工程实际中起重机吊重摆角和摆角角速度不易直接测量的问题,利用小车位置信息设计了状态观测器,对吊重摆角和摆角角速度信息进行估计。通过引入观测器输出与小车吊重系统输出之间的差值并经过观测器的增益向量调节送至观测器的输入端,合理配置观测器的极点,实现观测器对摆角和摆角角速度稳定、快速估计。仿真研究表明:基于状态估计的吊重摆角信息获取方法可行,观测器能在2s内实现在线观测,而且具有较强的鲁棒性;随着极点的增大,观测器对吊重和绳长的变化具有更宽的适应范围,但极点过大时,估计误差会出现上冲或下冲的现象;观测器对绳长的变化始终比对吊重的变化更敏感。     

具有未知干扰的无人机鲁棒滑模飞行控制

研究无人机飞行稳定性控制问题,由于无人机飞行控制系统存在时变外部干扰,飞行过程中升阴比变化激烈,控制稳定性难度较大。利用滑模控制良好的鲁棒能力提出一种神经网络的鲁棒飞行控制方法。因神经网络有良好非线性逼近能力,可对无人机飞行系统中的不确定进行在线逼近,并将神经网络权值误差引入到权值的自适应律中用以改善系统的动态性能。利用神经网络的组合,设计无人机鲁棒滑模飞行控制器。控制器分为两部分,一部分是等效控制器,另一部分是滑模控制器,能有效减小系统的跟踪误差。最后将所设计的鲁棒滑模控制对无人机飞行姿态控制进行仿真。仿真结果表明,新方法能提高无人机的鲁棒飞行控制能力且能实现无人机姿态的精确跟踪和稳定性控制。     

基于能量分析的桥式起重机防摆控制方法

针对欠驱动桥式起重机在自动化驾驶研究中负载升/落吊运动与台车水平位移联动时,负载摆动抑制效果和控制性能不能满足实际工程需要,易造成安全事故的问题,提出一种基于能量分析的桥式起重机联动系统非线性耦合防摆控制器.采用非线性耦合控制方法,构造新型储能函数,设计出非线性耦合防摆控制器.利用LaSalle不变性原理和Lyapunov方法对该闭环反馈系统稳定性进行严格的数学分析.理论推导、仿真与实验结果表明:相比于非线性跟踪控制器和局部反馈线性化控制器,所提非线性耦合防摆控制器具有更佳的控制性能,不仅提高了负载的吊运效率,而且能够有效抑制和快速消除负载摆角;在添加外部扰动的情况下,仍能取得良好的控制效果,具有较强的鲁棒性,为桥式起重机联动系统提供了一种新的防摆控制方法.     

伴有初始负载摆角的桥式起重机能量防摆控制

桥式起重机是一种广泛应用的大型搬运设备,在实际工作过程中,台车运动时会产生伴有初始负载摆角的负载摆动,影响工作效率并带来安全隐患.针对这种情况,设定期望的台车误差轨迹和摆角误差轨迹,将桥式起重机动力学模型转换为误差跟踪动力学模型,提出一种基于能量分析方法的桥式起重机防摆控制策略.通过LaSalle不变性原理和Lyapunov方法对闭环系统的稳定性进行理论分析.仿真与实验结果表明,所提防摆控制方法的控制性能几乎不受初始负载摆角的影响,可以保证桥式起重机在无初始负载摆角和带有初始负载摆角的情况下都能取得良好的控制效果,能够驱动台车准确到达目标位置,有效抑制并快速消除负载摆角,同时对外部扰动具有很强的鲁棒性.     

Application of intelligent sliding mode control with moving sliding surface for overhead cranes

In this paper, neural-based fuzzy logic sliding mode control with moving sliding surface has been designed for supervision of an overhead crane. A mathematical model has been established of the crane, and equations of motion have been obtained. First, the suitable sliding surface coefficient has been determined for the fixed sliding surface in the design of sliding mode control. The sliding surface has been moved by using neural-based fuzzy logic algorithm to eliminate disadvantage of the regular sliding mode control. By application of this control algorithm, the control performance incredibly increased. In the application, during the carriage of the load to a target which was 1 m away by a crane with 3 kg of load and 100 cm of rope length, the parameters of effected controllers were updated and their training was realized. In order to display the insensitiveness of the controller to parametric uncertainty, the value of the load was taken as 8 kg and the length of the rope was taken as 3 m and controls for a different target were realized. MATLAB program was used for numerical solutions, and results were examined graphically. Obtained results displayed the success of the algorithm of neural-based fuzzy logic sliding mode control.     

基于滑模方法的桥式吊车系统的抗摆控制

针对桥式吊车这类欠驱动系统，提出一种基于滑模控制的抗摆方法．该方法将系统状态分成两组。构造出一种双层滑动平面．结合桥式吊车系统数学模型的特点。求取了总的滑模控制量并进一步设计了控制器的参数．采用Lyapunov方法，从理论上证明了各级滑动平面的稳定性．仿真结果验证了该方法对于桥武吊车系统抗摆控制的有效性．     

集成神经网络与自适应算法的分数阶滑模控制

针对被控对象的参数时变和外部扰动问题,本文融合神经网络的万能逼近能力和自适应控制技术,并结合分数阶微积分理论,提出了基于神经网络和自适应控制算法的分数阶滑模控制策略.本文采用等效控制的方法设计滑模控制律,并利用神经网络的万能逼近能力估测控制律的变化,结合自适应控制算法和分数阶微积分理论抑制传统滑模控制系统的抖震,同时根据Lyapunov稳定性理论分析了系统的稳定性,最后给出了实验结果.实验结果表明,本文提出的基于神经网络和自适应控制算法的分数阶滑模控制系统,能保持滑模控制器对系统外部扰动和参数变化鲁棒性的同时,也能有效地抑制抖震,使得系统获得较高的控制性能.     

Adaptive Proportional-Derivative Sliding Mode Control Law With Improved Transient Performance for Underactuated Overhead Crane Systems

In this paper, an adaptive proportional-derivative sliding mode control (APD-SMC) law, is proposed for 2D underactuated overhead crane systems. The proposed controller has the advantages of simple structure, easy to implement of PD control, strong robustness of SMC with respect to external disturbances and uncertain system parameters, and adaptation for unknown system dynamics associated with the feedforward parts. In the proposed APD-SMC law, the PD control part is used to stabilize the controlled system, the SMC part is used to compensate the external disturbances and system uncertainties, and the adaptive control part is utilized to estimate the unknown system parameters. The coupling behavior between the trolley movement and the payload swing is enhanced and, therefore, the transient performance of the proposed controller is improved. The Lyapunov techniques and the LaSalle's invariance theorem are employed in to support the theoretical derivations. Experimental results are provided to validate the superior performance of the proposed control law.      

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

This 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.     

Payload pendulation and position control systems for an offshore container crane with adaptive‐gain sliding mode control

When container ports are not available for heavy ships, the offshore ship‐to‐ship transfer operation is an alternative method to an inland container terminal. This process is performed between a large container ship and a smaller ship, which is equipped with a container crane, called the mobile harbor or the ship‐mounted crane. The sea‐state condition is a crucial factor in open‐sea operations. The presence of waves, wind, and current disturbances excite the pendulum oscillations of the crane's hanging container. In this study, the problem of payload pendulation and container position for an offshore container crane using an adaptive‐gain sliding mode control (SMC) scheme is investigated. The primary control task during the loading and unloading process is to keep the container in the desired region under the harsh oceanic environment. The proposed control architecture incorporates an adaptive‐gain SMC with a compensation part and a prediction mechanism. Therein, a sliding surface is design to combine the desired sway motion of the payload with the desired trolley trajectory. Furthermore, a varying control gain is proposed in the sliding control, obtained by an adaption law that transitions the system into sliding mode. By constructing an appropriate Lyapunov function, we show that the proposed control law ensures the asymptotic stability of the ship‐mounted crane. Numerical simulations are presented to show the effectiveness and robustness of the proposed control system.     

新型框架式起重机的西门子电控系统解决方案

本文主要介绍西门子电控系统在国内首台海工专用框架式起重机上的应用,针对这种非传统起重机存在的控制技术难题提出相应的解决方案。其中介绍了驱动系统的容量校验计算,提出适合框架式起重机大车位置纠偏同步控制方法,应用起升同步及主从力矩控制,对传统起重机防止溜钩的方法进行改进,取得了较高的控制精度和稳定性,充分满足了生产过程的需要。     

绳长时变情况下轮胎式集装箱起重机非线性防摆控制算法

四绳轮胎式集装箱起重机由于自身的动力学特性较为复杂,目前仍缺乏稳定高效的控制手段.为解决港口起重机作业过程中台车定位精准度低、负载易受干扰摆幅大的问题,文章设计了一种面向工业场景的非线性反馈控制器.首先在未进行近似处理的前提下对起重机吊具摆动情况进行了建模分析.在此基础上,通过在控制器中引入摆幅反馈信息,实现了绳长时变...