Overhead cranes fuzzy control design with deadzone compensation

This article proposes a simple but effective way to control 3D overhead crane. The proposed method uses PID control at the start for rapid transportation and fuzzy control with deadzone compensation when the crane is close to the goal for precise positioning and moving the load smoothly. Only the remaining distance and projection of swing angle are applied to design the fuzzy controller. No plant information of crane is necessary in this approach. Therefore, the proposed method greatly reduces the computational efforts. Several experiments illustrated the encouraging effectiveness of the proposed method through a scaled 3D crane model. The nonlinear disturbance, such as abrupt collision, is also taken into account to check the robustness of the proposed method.     

A practical fuzzy controllers scheme of overhead crane

This paper presents fuzzy-based design for the control of overhead crane.Instead of analyzing the complex nonlinear crane system,the proposed approach uses simple but effective way to control the crane.There are twin fuzzy controllers which deal with the feedback information,the position of trolley crane and the swing angle of load,to suppress the sway and accelerate the speed when the crane transports the heavy load.This approach simplifies the designing procedure of crane controller;besides,the twin controller method reduces the rule number when fulfilling the fuzzy system.Finally,experimental results through the crane model demonstrate the effectiveness of the scheme.     

A practical fuzzy controllers scheme of overhead crane

1IntroductionThe overhead crane systemis widely usedinindustryformoving heavy cargos .Thus anti_sway and position controlhave become the requirements as a core technology forautomated crane systemthat are capable of flexible spatialautomatic conveyance .The purpose of crane control is to reduce the swing ofthe load while movingthe trolleyto the desired position asfast as possible .However ,the overhead crane has seriousproblems :the crane acceleration,required for motion,always induces undesir…     

适于长距离运输的分段吊车模糊控制

针对长距离吊车运输系统的特征,提出了分段切换因子模糊控制方法.该方法使用两个子模糊控制器分别用于抗摆和定位控制,并运用实值遗传算法选取模糊控制器的分段切换因子.仿真结果表明:该方法保证了定位精度并能有效地抑制超调,在加速阶段、运输阶段和减速阶段能够使载荷摆角最小,并且能够在目标位置进行消摆控制,其性能优于传统二次型最优控制.     

Inverse motion planning method for overhead crane systems with state constraints

The trajectory planning problem with state constraints of overhead crane systems is considered in this paper. A new method, that is, an inverse motion planning method, is proposed. On this basis, a new trajectory planner is designed. The payload swing angle trajectory is designed first, and then by substituting it into the dynamic equations, the trolley trajectory is derived. For any transportation tasks, the adjustable parameter of the planner is computed by solving the state constraints such that the system states; that is, the trolley acceleration, trolley speed, and payload swing angle will not exceed their predefined constraints. Several experimental tests are conducted to verify the swing elimination performance of the proposed method.     

An Enhanced Coupling Nonlinear Tracking Controller for Underactuated 3D Overhead Crane Systems

An enhanced coupling nonlinear tracking control method for an underactuated 3D overhead crane systems is set forth in the present paper. The proposed tracking controller guarantees a smooth start for the trolley and solves the problem of the payload swing angle amplitude increasing as the transferring distance gets longer for the regulation control methods. Different from existing tracking control methods, the presented control approach has an improved transient performance. More specifically, by taking the operation experience, mathematical analysis of the overhead crane system, physical constraints, and operational efficiency into consideration, we first select two desired trajectories for the trolley. Then, a new storage function is constructed by the introduction of two new composite signals, which increases the coupling behaviour between the trolley movement and payload swing. Next, a novel tracking control strategy is designed according to the derivation form of the aforementioned storage function. Lyapunov techniques and Barbalat's Lemma are used to demonstrate the stability of the closed‐loop system without any approximation manipulations to the original nonlinear dynamics. Finally, some simulation and experiments are used to demonstrate the superior transient performance and strong robustness with respect to different cable lengths, payload masses, destinations, and external disturbances of the enhanced coupling nonlinear tracking control scheme.     

Novel Approach for Adaptive Tracking Control of a 3-D Overhead Crane System

Traditionally, overhead crane systems are operated by humans. However, automatic operation would reduce both the risk and the personnel costs. From the engineering viewpoint, the most important issues in crane motion are high positioning accuracy, short transportation time, small sway angle, and high safety. Hence, stabilization control is particularly concerned. In this paper, a novel adaptive control scheme including both the cart motion dynamics and the swing angle dynamics is designed to ensure the stability of the closed-loop system. No system parameters are needed, and accurate position tracking as well as minimal swing is achieved. The stability of the closed-loop system is proved via Lyapunov theory. Simulation studies and experiments are performed to demonstrate the validity of the proposed control scheme.     

起重机模糊神经网络防摇摆控制仿真研究

起重机起重过程中吊物摇摆系统模型的复杂性,非线性,时变性导致传统PID控制在此过程中存在控制效果不理想,控制参数难以整定等问题。利用模糊控制不依赖精确数学建模,以及神经网络的自学习性等优点。提出一种将起重机传统PID控制与模糊神经网络相结合的控制方法。通过仿真对比发现改进后的控制方法能够有效降低系统稳定的调节时间,吊装货物的摆幅也得到减少。     

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。     

基于逆系统方法的内模控制在吊车消摆运动中的应用

针对非线性、欠驱动的桥式吊车水平运动系统，先运用非线性逆系统方法将其转化为伪线性系统，然后按照线性系统理论设计内模控制器来控制吊车的水平定位．同时设计了一个角度反馈控制器来确保摆角迅速衰减．最后和常规PID、模糊控制做了比较．实验结果表明，本方案能保证定位无静差、摆角迅速衰减，同时具有良好的抗干扰能力和较强的鲁棒性，控制效果优于PID和模糊控制．     

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.     

龙门吊车系统的动力学建模

针对龙门吊车这一典型的欠驱动机械系统,采用拉格朗日方程的方法建立了其动力学模型。该模型同时考虑了吊车系统水平方向、前后方向和垂直方向上的三维运动以及由这些运动导致的负载摆角变化,且负载在二维空间的摆动角度通过特殊定义的二维平面的摆角进行描述。根据负载摆角的定义方式,取消三维吊车系统动力学模型的一个运动自由度直接将得到广泛研究的二维吊车系统的动力学模型。为了便于进行控制器的设计,还给出了近似条件下的龙门吊车系统的线性化模型。最后,数字仿真实验结果证明了动力学模型的有效性。     

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.     

A novel trajectory planning-based adaptive control method for 3-D overhead cranes

A three-dimensional (3-D) overhead crane is a complicated nonlinear underactuated mechanical system, for which high-speed positioning and anti-sway control are the kernel objective. Existing trajectory-based methods for 3-D overhead cranes focus on combining efficient and smooth trajectories with anti-sway tracking controllers without regard for payload motion; moreover, the exact value of plant parameters is required for accurate compensation during the control process. Motivated by these facts, we present a two-step design tracking strategy which consists of a trajectory planning stage and an adaptive tracking control design stage for 3-D overhead cranes. As shown by Lyapunov techniques and Barbalat's Lemma, the proposed controller guarantees asymptotic swing elimination and trolley positioning result in the presence of system uncertainties including unknown parameters and external disturbances. Simulation results also showed the applicability of the proposed method with good robustness against parameter uncertainties and external disturbances.     

基于状态估计的起重机吊重摆角信息获取方法

针对工程实际应用中桥式起重机或门式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,该差值经过观测器的增益向量调节送至观测器的输入端,将观测器的极点配置在负实轴上,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,观测器具有较 强的鲁棒性;随极点增大,观测器对吊重和绳长变化具有更宽的适应范围,但极点过大时,会出现估计误差上冲或 下冲现象;当极点确定时,观测器对绳长变化比吊重变化敏感．     

一种直接基于摆角约束的欠驱动桥式吊车轨迹规划方法

针对非线性桥式吊车系统,本文提出了一种新颖的基于摆角约束的轨迹规划方法.为了提高运送过程的效率和安全性,论文设计了期望轨迹以实现如下优点: 1)使台车很快到达目标位置; 2)将负载摆角抑制到可接受的范围之内; 3)当负载在目标位置停止时无残余摆动.具体而言,所设计的轨迹由三个阶段构成,每一阶段均根据抗摆和零残余摆角的要求来构造摆角曲线,在此基础上,利用桥式吊车的非线性运动学方程分析得到台车轨迹.论文引入了一种优化机制对运送时间,最大摆角等指标进行折衷考虑.文中通过仿真和实验结果表明了所设计的直接基于摆角约束的轨迹规划方法的性能.     

一种直接基于摆角约束的欠驱动桥式吊车轨迹规划方法（英文）

This paper proposes a novel swing constraint-based trajectory planning method for nonlinear overhead crane systems.To enhance the efficiency and security of the transportation process, some desired trajectories are designed to achieve the following merits: 1) leading the trolley to reach the destination sufficiently fast; 2) keeping the payload swing in an acceptable domain;3) eliminating the residue swing when the trolley stops at the desired position. Specifically, the trajectories are divided into three stages. For each stage, the desired curve of the swing angle is directly constructed in accordance with anti-swing and zero-residual swing requirements, based on which the trolley trajectory is then obtained by analyzing the nonlinear kinematics of the crane system.An optimization mechanism is introduced to make intelligent compromises among the indices of transportation time, maximal swing angle, and so on. Both simulation and experimental results are provided to demonstrate the performance of the proposed direct swing constraint-based trajectory planning method.     

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.     

采用神经网络的双吊车自适应防摆控制

由于工业实践对运输能力提出了更高的要求,双吊车的应用日益广泛.然而其动力学模型非线性很强,因此控制器结构十分复杂.另一方面,大型货物的摆动很难抑制,这给双吊车的自动化带来了巨大的挑战.为了处理以上问题,首先,采用神经网络准确地估计了系统的模型,在此基础上提出了一种自适应防摆控制方法,很好地实现了双吊车系统的防摆控制;然后,采用李雅普诺夫方法,严格地证明了系统在平衡点的渐近稳定性;最后,通过大量的实验结果,验证了该方法具有良好的性能.     

A unified symplectic pseudospectral method for motion planning and tracking control of 3D underactuated overhead cranes

In this paper, a unified symplectic pseudospectral method for motion planning and tracking control of 3D underactuated overhead cranes is proposed. A feasible reference trajectory taking constraints into consideration is first generated offline by the symplectic pseudospectral optimal control method. Then, a trajectory tracking model predictive controller also based on the symplectic pseudospectral method is developed to track the reference trajectory. At each sampling instant, the trajectory tracking controller works by solving an open‐loop optimal control problem where linearized system dynamics is used instead to improve the computational efficiency. Since the symplectic pseudospectral optimal control method is the core algorithm for both offline trajectory planning and online trajectory tracking, constraints on state variables and control inputs can be easily imposed and hence theoretically guaranteed in solutions. By selecting proper weighted matrices on tracking error and control, the developed controller could achieve control objectives in both accurate trolley positioning and fast suppressing of residual swing angles. Simulations for 3D overhead crane systems in the presence of perturbations in initial conditions, an abrupt variation of system parameter, and various external disturbances demonstrate that the developed controller is robust and of excellent control performance.