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.     

基于输入整形策略的船上回转吊车防摆控制

为了解决船上吊车的防摆问题,实现负载快速准确的定位,建立了系统的空间三维数学模型,提出了基于输入整形的前馈开环消摆控制策略。对定摆长条件下系统控制输入设计了ZVD(Zero Vibration and Derivative)输入整形器;基于输入整形器灵敏度曲线,利用矢量求和的方法设计了对称3峰的EI(Extra Insensitive)输入整形器,解决了在绳长变化时吊车系统防摆的控制问题;指出了输入整形对海浪影响的抑制作用。仿真结果验证了输入整形对于船上吊车防摆控制的有效性。     

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.     

带有完整约束的双吊车系统输入整形控制

作为一种重要的物料运输工具,桥式吊车在各类工业场景中发挥着举足轻重的作用.然而随着负载体积/质量的增大,很多时候不得不使用两台吊车来协同运送负载.目前对于这类双吊车系统的防摆研究仍然较少.本文针对这一情况,率先提出了一种输入整形控制方法.具体来说,首先分析了双吊车系统中存在的完整约束,通过对系统模型的合理简化,在不失准确性的情况下获得了台车位移与负载姿态角之间的近似动力学关系.在此基础上,求取出系统真实的振荡周期并设计出了合适的输入整形器.该整形器能够在不影响台车定位的情况下,充分抑制负载的摆动,并且对系统参数不确定性具有良好的鲁棒性.仿真和实验结果也证明了这一点.     

基于嵌套饱和方法的吊车系统非线性控制

针对吊车系统定位和防摆的控制要求,提出了一种基于嵌套饱和方法的非线性控制策略。对吊车系统动力学方程进行部分反馈线性化,并通过坐标变换将其转化为便于控制器设计的严格前馈级联规范型;在此基础上利用嵌套饱和非线性控制方法设计了吊车定位防摆控制器。仿真结果表明,该方法在较小的控制力作用下实现了吊车系统的定位和防摆,并且对于吊车系统参数的变化具有很强的鲁棒性。     

欠驱动桥式吊车消摆跟踪控制

对于桥式吊车系统而言,其控制目标是将货物快速、精确、摆动尽可能小地运送到目标位置.为此,本文提出了一种新型的轨迹跟踪控制策略,可在保证负载快速平稳运送的同时,有效地抑制并消除整个过程中负载的摆动.具体而言,通过对吊车动力学模型进行一系列的变换,设计了一种新颖的跟踪控制器,并对闭环系统信号的有界性与收敛性进行了理论分析.与调节控制方法相比,本文方法可保证台车的平滑启动与运行;此外,本方法放宽了已有轨迹跟踪控制方法对参考轨迹的约束条件,更具实用性与一般性.实验结果表明,本文设计的控制器能取得优于已有方法的控制效果,并对外界干扰具有很强的鲁棒性.     

吊车卷绳圈数计数电路

为配合吊车防摆系统在吊绳变化较大时切换控制参数设计了吊车卷绳圈数计数电路，并进行了安装，调试，对电路及结果进行了分析。因为吊车的卷绳可以放长和缩短，所以，带动卷绳的转动可正转和反转，我们设计的是可逆计数器，为保证安全和吊车运动时吊绳保持适当的长度，当卷绳转数超过计数器计数范围时，能够自动返回零转并重新计数，实验结果表明，此电路能很好的实现吊车卷绳正反转圈数的计数。     

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。     

吊车系统无线网络监控的可行性研究

针对武钢三炼钢吊车系统智能调速装置故障记录手段匮乏及系统分析效率低的问题,介绍无线网络监控系统的应用优势,并根据吊车系统的现状对监控系统应用的可行性进行分析。     

吊车防摆最优调节器设计

本文对吊车在吊装货物时如何消除货物的摆动进行了研究,提出了利用最优状态调节器进行消摆的方案,并进行了计算机仿真和在吊车模型上的实时控制实验,结果表明,该方法具有很好的消摆效果和较强的鲁棒性。     

Tracking and load sway reduction for double‐pendulum rotary cranes using adaptive nonlinear control approach

Because of the existence of rotational boom motion, the load sway characteristics is more complex. In particular, when the sway presents double‐pendulum phenomenon, the design of the controller is more challenging. Furthermore, the uncertain parameters and external disturbances in crane system make it difficult for traditional control methods to obtain satisfactory control performance. Hence, this paper presents an adaptive nonlinear controller based on the dynamic model of double‐pendulum rotary crane. Unlike a traditional method, the proposed one does not need to linearize the crane system for controller design; therefore, the control performance can be guaranteed even if the system states are far away from the equilibrium point. By using Lyapunov technique and LaSalle's invariance theorem, it is strictly proved that the whole control system is asymptotically stable at the equilibrium point. The effectiveness of the presented controller is demonstrated via comparative simulations.     

ICT支持的塔吊安全管理框架——回顾与展望

塔吊是建筑工程中使用频率最高的垂直运输工具.由于塔吊的运行风险较高,提高其安全管理水平成为业界亟待解决的问题.近年来,信息与通信技术(ICT)逐渐被应用于塔吊安全管理,但目前该领域的应用多为单点开发且智能化水平偏低,未能很好地满足现有的塔吊安全管理需求.通过查阅近十几年的塔吊安全管理领域的相关文献,将国内外学者对塔吊安...     

Review of Antiswing Control of Shipboard Cranes

Shipboard cranes are extensively utilized in numerous fields such as cargo transferring and offshore engineering. The control of shipboard cranes, especially the antiswing control of payloads, has attracted much research attention due to their typical underactuation characteristics and complicated dynamics. Through comparisons of the traditional land-fixed cranes, a brief review on modeling and dynamics analysis is presented to illustrate the tremendous challenges and difficulties in controller design for shipboard cranes. A comprehensive review and brief analysis of shipboard crane control strategies are further presented. Some future research directions are also put forward for reference. It is expected that the paper will be useful for improving existing control schemes and generating novel control approaches for shipboard crane systems.      

基于伪谱法的双摆吊车时间最优消摆轨迹规划策略

在工业生产过程中,桥式吊车系统经常会体现出双摆系统的特性,导致更多欠驱动状态量的出现,增大控制难度.基于此,论文提出了一种针对双摆桥式吊车系统的时间最优轨迹规划方法,可以得到全局时间最优且具有消摆能力的轨迹.具体而言,为方便地构造以时间为代价函数的优化问题,首先对系统运动学模型进行相应的变换;在此基础上,考虑包括两级摆角及台车速度和加速度上限值在内的多种约束,构造出相应的优化问题;然后,利用高斯伪谱法(Gauss-pseudospectral method, GPM)将该带约束的优化问题转化为更易于求解的非线性规划问题,且在转化过程中,可以非常方便地考虑轨迹约束.求解该非线性规划问题,即可得到时间最优的台车轨迹.不同于已有的大多数方法,该方法可获得全局时间最优的结果.最后,通过仿真与实验结果验证了这种时间最优轨迹规划方法具有满意的控制性能.     

Kinematic coupling-based trajectory planning for rotary crane system with double-pendulum effects and output constraints

When the payload is too large or the hook mass cannot be ignored, the double-pendulum phenomenon may happen in rotary cranes practical applications. The increase in dynamic complexity makes it more difficult to fast and accurate positioning while suppressing swing during cargo transportation. Moreover, output constraints should be considered in actual crane systems. In this paper, a novel kinematic coupling-based trajectory planning method is proposed for double-pendulum rotary cranes with the constraints on angular acceleration and velocity of the boom. The proposed trajectory consists of two parts: a positioning reference component and a swing-eliminating component. The positioning reference trajectory takes into account the physical constraints of the actuator. The swing-eliminating trajectory is designed based on the kinematic coupling relationship among the boom luffing, the hook swing and the payload swing. Lyapunov techniques and Barbalat lemma are used for stability analysis. Numerical simulation and real experiments verify the superior control performance and robustness of the proposed control method.     

An advanced cargo handling system operating at sea

Mobile Harbor (MH) was recently proposed by KAIST as a novel maritime cargo transfer system that can go out to a container ship anchored in deep water and handle containers at sea. Since the system operates in at-sea conditions with waves and wind, the MH crane should be designed to suppress the swing motion of a spreader and compensate the relative motion between the MH and a container ship. For that purpose, we devised a state-of-the-art crane system equipped with a dual stage trolley, tension controller, and intelligent spreader with 3 degrees of freedom. We also integrated a robust sensing system to measure remote motions in harsh open-sea condition. With these advanced systems, we achieved swing free, position, tilting, and heave control systems for precise and safe cargo transfer. Experimental results with a 1/20 scale MH crane show the feasibility of the proposed system for at-sea cargo transfer.     

倒立摆系统自适应高阶微分反馈控制

利用提取的系统高阶微分信息,提出了自适应高阶微分反馈控制器.某种程度上该控制器不依赖于单输入单输出(SISO)非线性仿射系统的模型.并且分析了闭环系统的稳定性和鲁棒性.通过将摆角方程的位移加速度看作是控制输入,将倒立摆系统转化成相互影响的两个SISO仿射系统,从而用两个串级高阶微分反馈控制器成功地实现了倒立摆系统的镇定与调节.数字仿真表明,控制器对摆的基准模型实现了较为满意的控制,而且该控制方法对非线性摩擦项,对摆长、摆质量、小车质量等参数变化以及外扰动具有强鲁棒性.     

深海起重机系统的实时轨迹规划方法

近年来, 随着海洋资源的不断开发与海洋工程的全球化推进, 深海起重机得到了广泛应用, 其控制问题也引起研究人员的极大关注. 在深海作业环境中, 由于吊运过程受到水流作用力的影响, 负载摆动幅度增大, 系统状态量间非线性耦合关系增强, 使系统控制难度加大. 为此, 本文针对深海起重机系统提出了一种实时轨迹规划方法. 具体而言, 通过分析系统动力学特性和状态变量之间复杂的耦合关系, 提出了一种实时规划轨迹的方法, 并从理论上证明了该方法可在使台车准确快速到达指定位置的同时, 有效抑制负载摆动. 最后, 一系列仿真结果证明了所提方法的良好性能.     

Analysis of the energy‐based swing‐up control for the double pendulum on a cart

Designing and analyzing controllers for mechanical systems with underactuation degree (difference between the number of degrees of freedom and that of inputs) greater than one is a challenging problem. In this paper, for the double pendulum on a cart, which has three degrees of freedom and only one control input, we study an unsolved problem of analyzing the energy‐based swing‐up control which aims at controlling the total mechanical energy of the cart‐double‐pendulum system, the velocity and displacement of the cart. Under the energy‐based controller, we show that for all initial states of the cart‐double‐pendulum system, the velocity and displacement of the cart converge to their desired values. Then, by using a property of the mechanical parameters of the double pendulum, we show that if the convergent value of the total mechanical energy is not equal to the potential energy at the up–up equilibrium point, where two links are in the upright position, then the system remains at the up–down, down–up, and down–down equilibrium points, where two links are in the upright–down, down–upright, and down–down positions, respectively. Moreover, we show that each of these three equilibrium points is strictly unstable in the closed‐loop system by showing that the Jacobian matrix valued at each equilibrium point has at least one eigenvalue in the open right half plane. This shows that for all initial states with the exception of a set of Lebesgue measure zero, the total mechanical energy converges to the potential energy at the up–up equilibrium point. This paper provides insight into the energy‐based control approach to mechanical systems with underactuation degree greater than one. Copyright © 2010 John Wiley & Sons, Ltd.