吊重防摇控制的起重机快速对位关键技术研究

起重机的小车和吊重之间一般采用柔性钢绳联结，由于大、小车和吊重存在惯性，小车或大车的运行使吊重产生摇摆，不利于起重机快速对位。一般吊重防摇的被动控制较主动控制容易实现。吊重防摇、减摇的型式一般有机械式、液压油缸式、钢丝绳索式、机械电子式和智能电子式，文中的研究重点在液压油缸式和智能电子式减摇系统。对起重机吊重系统的动力学分析是解决起重机快速对位问题的基础。文中由桥式起重机建立了起重机吊重系统动力学方程，并在线性简化的基础上得出吊重二自由度摆角模型。仿真结果表明：吊重的起升绳长和大、小车运行的加(减)速度是影响吊重摆角的主要因素，其中大、小车运行加(减)速度对摆角的影响较绳长对摆角的影响显著：起重机的大车和小车运行对吊重摇摆的影响效果是相同的。液压油缸式减摇系统在集装箱起重机中应用较多，为了能更好地为液压减摇系统的工程设计提供理论依据和指导，文中根据液压减摇系统的结构特点和小车吊重系统的运动特点对液压油缸式减摇系统在工程适用范围内建立了动力学方程，对减摇系统进行了动力学分析，模拟实际工况进行了动态仿真，结果表明：吊重摆角按指数形式衰减，影响减摇系统减摇效果的因素有减摇系统的结构参数、起升质量、起升绳长和起升速度。对于具体的液压减摇系统，在最佳结构参数载荷比范围或匹配起升质量时，可以得到良好的减摇效果。一般通过相应的传感器实时采集小车位置和速度、吊重摆角和摆角角速度以及小车驱动力等状态变量信息，并提供给防摇控制系统。考虑到吊重摆角等变量现场测量的难度和成本，文中针对电压控制小车驱动电机的小车吊重动力学系统，通过设置全状态观测器或降维观测器对相关变量进行现场观测，即重构状态变量空间，从而将相关变量的估计信息提供给防摇控制系统。通过采集小车位置信息可以设置全状态观测器对包括小车位置在内的所有状态变量进行观测：通过采集小车位置和速度信息可以设置降维观测器对吊重摆角、摆角角速度和驱动力进行观测。观测器的相应状态变量的观测时间与小车吊重系统动力学参数、观测器的极点和相应状态变量的初始值有关。在给定系统动力学参数和相应状态变量的初始条件下可以绘制观测器极点与对应状态变量的观测时间关系曲线，为了使观测器精确重构状态变量空间并具有良好的动态特性，可以将观测器的极点配置在复平面负实轴上和该曲线的平缓变化区域。由小车吊重开环系统动力学特性和开环系统的极点在复平面的分布形态，开环系统本身是不稳定的。通过引入状态反馈增益调节器构成闭环控制系统，其中状态变量信息由传感器现场采集或观测器观测所得。采用极点配置法(极点位移法)，通过考虑控制系统复平面上一对闭环主导极点，控制系统的其余极点可以配置在离这对主导极点左侧较远处，用类似二阶系统性能分析方法获得反馈控制器的增益调节参数，通过调节参数配置反馈控制系统的极点为期望极点，从而使吊重的摆动能在小车的目标位置和期望时间衰减为零。当反馈控制系统引入状态观测器时，要求观测器对状态变量的观测速度比反馈控制器对状态变量的调节速度快。文中进行了观测器和反馈控制器的设计，仿真结果表明在小车目标位置、指定调节误差范围内吊重摆角能在期望的时间衰减为零，各状态变量均有良好的动态响应特性，说明了观测器和控制器设计的合理性和有效性。起重机现代智能电子吊重防摇控制系统的物理实现须建立在现代电子电路设计基础上。文中对起重机快速对位的实现提出基于控制器局域网(CAN)总线形式的数字信号处理(DSP)控制系统，合理设计了CAN总线控制系统的智能节点电路，对吊重摆角的三角形测量方法给出了具体实施方案。这些关键技术的解决是吊重防摇控制理论和方法进一步物理实现的前期工作。
活动房
Generally, the trolley of overhead cranes or gantry cranes and the load are connected by the flexible wire rope. The operation of the trolley or the crane causes the load’s sway because of the inertia of the trolley, crane and load. Load’s sway is not favorable to the crane’s fast contraposition. Passive control of the load’s anti-sway is often easier than the active control. The kinds of the load’s anti-sway usually include mechanical system, hydraulic system, wire rope system, mechanical electronic system and intelligent electronic system. Research emphasis of this thesis is on the hydraulic and the intelligent electronic anti-sway system. Dynamic analysis for the crane-load or the trolley-load system is the foundation for solving the problem of the crane’s fast contraposition. The crane-load system’s dynamic equations were constructed for the overhead cranes, and the two-degree-of-freedom angle model was derived based on linear simplification for the system’s dynamic equations. Dynamic simulation results show that load’s hoist rope length and the acceleration of the crane or the trolley are the main influencing factors for the load’s swing angle, and the acceleration has greater effect on the swing angle than the rope length, and the effect of the crane’s running and the effect of the trolley’s running on the load’s swing angle are identical.Hydraulic anti-sway system has extensive application in the container cranes. In order to provide theoretic foundation and guidance for the engineering design of the hydraulic anti-sway system, in this thesis, the dynamic equations were constructed in the field of engineering application on the base of the characteristic of the anti-sway system’s structure and the trolley-load system’s dynamics. Then dynamic characteristic was analyzed for the hydraulic anti-sway system. Dynamic simulation according to the container cranes shows that the load’s swing angle may be attenuated to zero according to the index form, and the anti-sway system’s structure parameter, hoist load mass, hoist rope length and hoist velocity can affect the anti-sway effect. For the concrete hydraulic anti-sway system, there exists better anti-sway effect when the anti-sway system has the matching hoist load or the optimal ratio range of the structure parameter to the hoist load.The state variables information including the trolley’s position and velocity, the load’s swing angle and swing angle velocity and the trolley’s driving force are often collected by corresponding sensors, then these information is provided to the anti-sway control system .But considering the difficulty and cost of site measurement for variables such as the load’s swing angle, in this thesis, for the trolley-load’s dynamic system drove by the DC motor, the corresponding variables can be observed through setting a full-state observer or a reduced dimension observer, and that is to reconstruct the state variable space. Then corresponding variables’ estimated information may be provided to the anti-sway control system. The full-state observer was designed to observe all variables including the trolley’s position through collecting the trolley’s position information. The reduced dimension observer was designed to observe the load’s swing angle, swing angle velocity and driving force through collecting the trolley’s position and velocity information. The dynamic parameters of the trolley-load’s system, the observer’s pole location and the initial value of the corresponding state variable can affect the corresponding state variable’s observation time. The curves of observation time vs. observer’s pole location can be plotted when the system’s dynamic parameters and the corresponding state variable’s initial value are determinate. In order to reconstruct the state variables precisely, the observer’s pole is placed on the negative real-axis in the complex plane and in the flat range on the curves.The trolley-load open-loop system is unstable according to the dynamic characteristic of the trolley-load open-loop system and the open-loop system’s pole location in the complex plane, the closed-loop control system is constructed through introducing the state feedback gain regulator. The state variables information is offered through collecting with site sensors and observing with the observer. Considering a pair of closed-loop dominant poles in this control system’s complex plan, the other poles of this control system may be distantly placed in the left side of the dominant poles based on pole placement (pole displacement) method. The gain adjusting parameter of the feedback controller is achieved with the analysis way of similar 2nd-order system. The feedback control system’s poles expected are placed with the adjusting parameter, and the load’s swing may be attenuated to zero at the target position and the expected adjusting time. When the state observer is introduced into the feedback control system, the observer’s observing state variables must be faster than the feedback controller’s adjusting state variables. In this thesis, the observer and feedback controller were designed. Simulation results show that the load’s swing angle may be attenuated to zero at the trolley’s expected position and adjusting time in the adjusting error range, and the anti-sway control system has favorable stability and dynamic characteristic. So the design of the observer and feedback controller is reasonable and effective.Physical realization of the cranes’ modern intelligent electronic anti-sway control system must be based on the modern design of electronic circuit. In this thesis, the DSP anti-sway control system based on CAN bus structure was reasonably designed, and the concrete implementation scheme for the load’s swing angle’s measurement with triangle method was expounded. These key technologies’s solving are the preparatory work on the physical implementations for these anti-sway control theory and method.