冗余多轴振动台耦合特性分析及其控制策略研究

发布时间：2018-03-19 23:08

  本文选题：冗余振动台　切入点：流量非线性补偿　出处：《哈尔滨工业大学》2015年博士论文　论文类型：学位论文

【摘要】：中国是地震多发国家,振动台作为在实验环境中可以实现地震信号模拟的试验设备,广泛的用于高层建筑、桥梁和大型结构件振动试验检测。冗余多轴振动台可以克服小尺寸缩尺模型所带来的试验精度问题,并能评价分析重载大型结构试件的地震破坏机理和结构整体抗震能力。本课题来源于国家自然科学基金项目:“超冗余长行程并联驱动地震模拟台内力耦合机理及其抑制方法研究”以及“超冗余长行程并联驱动地震模拟台模态建模及压力镇定控制机理研究”,对冗余多轴液压振动台的柔性基础耦合、内力耦合和动力学耦合特性进行了深入研究,并提出了相应的解耦控制策略。冗余液压振动台激振器伺服阀的流量非线性将导致加速度波形失真现象,为此,本文建立了液压系统的非线性模型,通过流量压力的非线性方程设计了其非线性逆模型,实现了流量的非线性补偿,仿真结果验证了其有效性。同时,通过基于状态空间的状态反馈设计了自由度的三状态反馈控制器,并对其稳定性进行了分析,给出了理想三阶传递函数所对应的三状态控制参数。当冗余振动台的反力墙柔性较大时,会影响振动台的整体特性,使得振动台的频宽降低。本文建立了柔性基础耦合下液压振动系统的模型,通过等效二自由度系统的模态研究,确定了综合固有频率、液压固有频率和基础固有频率之间的关系,并分析了柔性基础的参数对系统动态特性的影响,改进了常规的三状态前馈控制器。仿真结果表明前馈改进控制可以有效拓展柔性基础耦合时的系统频宽。同时,为了提高高频时正弦信号的跟踪精度,克服传统幅相控制参数设置繁琐的缺点,提出了新的幅相控制策略。在时域内给出了正弦信号的幅值误差、相位误差和零点偏移的辨识公式。结合辨识误差,建立了三个参数的迭代序列,在考虑低频快速性与高频稳定性的基础上,对迭代速率进行了分段处理,并分别给出了辨识和迭代部分有限状态机程序的计算机实现方法。冗余振动台的液压缸数大于控制的自由度数,电液伺服系统间特性不一致会导致系统产生较大的内力耦合。为了分析内力耦合特性,首先建立了单冗余系统在自由度控制下的内力耦合模型,给出了稳态时内力与伺服阀零偏、安装精度、测量误差和平台刚度之间的关系。然后将冗余振动台的平台分别沿水平和垂直方向进行网格划分,建立了其刚柔耦合动力学模型,并对自由度控制下的内力进行了仿真分析。最后根据稳态时内力与伺服阀零偏的关系,提出了静态内力积分补偿控制策略来消除稳态内力。对于动态内力,则在冗余振动台内力耦合空间分析的基础上,通过内力合成矩阵,对合成内力进行闭环反馈补偿,由冗余变形分解矩阵将补偿量分配到各液压伺服阀的输入端,提出了动态压力的均衡控制策略。仿真结果表明所提的内力控制方法能有效降低冗余液压振动台的静态及动态耦合内力,减少内力控制参数。冗余振动台在带负载工作时,由于负载的偏心,各个自由度之间会出现动力学耦合现象。为此,建立了动力学耦合模型,根据动力学耦合模型引入耦合力观测器,经过雅可比矩阵变换,将耦合力分解到各液压缸上,视耦合力为液压系统的干扰力进行控制,并给出了干扰力的顺馈补偿控制策略,提出基于动力学模型下的解耦控制策略。基于动力学模型的解耦控制需要对加速度反馈信号进行微分处理,由于实际控制时加速度反馈信号的噪声较大,在此基础上,提出了模态的解耦控制策略。将液压缸视为液压弹簧,分析了冗余振动台的自由振动模态方程,通过模态矩阵及其逆矩阵,将冗余振动台由自由度空间转到无耦合的模态空间进行控制,从而实现了冗余振动台的模态解耦控制。同时通过对模态矩阵与模态自由度耦合特性之间关系的分析,给出了实验确定模态矩阵的方法。仿真分析显示,与基于动力学模型的解耦控制相比,模态空间解耦控制能更有效的降低冗余振动台自由度间的动力学耦合。基于x PC Target快速控制原型技术开发了用于控制冗余多轴振动台的实验系统,对上述各种耦合特性及解耦算法进行了详细的实验分析和研究。实验结果验证了本文所提出解耦控制策略的先进性和有效性。
[Abstract]:Chinese is an earthquake prone country, shaking table as in the experimental environment can realize the seismic signal simulation test equipment, widely used in high-rise buildings, bridges and vibration test of large structures detection. Redundant multi axis shaking table can overcome the small scale model caused by the test accuracy problem and evaluation analysis of large structure overloading the specimen of earthquake damage the overall seismic mechanism and structure. This subject comes from the National Natural Science Fund Project: "the earthquake simulation platform coupling mechanism and research method as well as the" suppression "super long stroke redundant parallel drive seismic modeling and Simulation Study on the mechanism of modal pressure stabilization control super long stroke" redundant parallel drive, flexible coupling the redundant multi axis hydraulic vibration table, coupling and dynamic coupling characteristics are studied deeply, and put forward the corresponding decoupling control strategy. The flow of nonlinear redundant hydraulic vibration table vibration servo valve will cause acceleration waveform distortion, therefore, this paper establishes a nonlinear model of hydraulic system, nonlinear equation by flow pressure design of the nonlinear inverse model, the nonlinear compensation flow, simulation results verify its effectiveness. At the same time, through the state space. State feedback design of three degrees of freedom based on state feedback controller, and analyzes the stability and control parameters of the three state three order transfer function corresponding to the given. When the redundant shaking table reaction wall flexibility, will affect the overall characteristics of the shaking table, the shaking table to reduce the bandwidth in this paper. The establishment of the hydraulic vibration system of flexible foundation under the coupling model, through the modal analysis of the equivalent of two degree freedom system, determine the comprehensive natural frequency, natural frequency and medium hydraulic The relationship between the basic frequency, and analyzed the influence of parameters of flexible foundation on the dynamic characteristics of the system, improve the state of three conventional feedforward controller. The simulation results show that the system can effectively expand the bandwidth improvement of feedforward control based flexible coupling. At the same time, in order to improve the tracking accuracy of sinusoidal signal frequency, amplitude and phase control to overcome the traditional parameter setting complicated, put forward a new phase and amplitude control strategy. In the time domain is given the amplitude error of sinusoidal signal, the phase error and the offset identification formula of zero. Combined with the identification error, iterative sequence established three parameters, considering the low speed and high frequency stability, the iteration rate the segmentation processing, and implementation methods are presented for identification and iterative part finite state machine program. The hydraulic cylinder vibration control is greater than the number of redundant freedom The degree of the electro-hydraulic servo system between the characteristics of inconsistency will cause the system to produce force coupling is greater. In order to analyze the coupling characteristics of internal forces, internal force coupling model is established firstly single redundant system in degrees of freedom under the control of steady-state internal force and servo valve zero bias, the installation accuracy, the measurement error and the relationship between the stiffness of the platform. Then redundant shaking table platform respectively along the horizontal and vertical direction mesh, establishes the rigid flexible coupling dynamics model, and the internal force under the control of the degrees of freedom were analyzed. According to the steady state of internal force and servo valve bias, the static force integral compensation control strategy to eliminate steady-state internal force for the dynamic force, based on redundant shaking table coupling space analysis, the internal force of the internal force of matrix synthesis, synthesis of closed-loop feedback compensation by redundant deformation The amount of compensation allocation matrix solution to the input end of each hydraulic servo valve, put forward dynamic pressure balancing control strategy. Simulation results show that the force control method proposed can effectively reduce the static and dynamic coupling force of redundant hydraulic vibration table, reduce the internal force of the control parameters. The redundant shaking table with the load when working, because the load eccentricity, between different degrees of freedom will appear dynamic coupling phenomenon. Therefore, to establish the dynamic coupling model, according to the dynamic coupling coupling force observer, by Jacobi matrix transform, the coupling force is decomposed into various hydraulic cylinders, as the coupling force for the disturbance force of hydraulic system control, feedforward compensation and control strategy given the interference force, put forward decoupling control strategy based on dynamic model. The dynamic model of decoupling control of acceleration feedback signal processing based on differential, by In the actual control of acceleration feedback signal noise, based on the proposed modal decoupling control strategy. The hydraulic cylinder for hydraulic spring, analyzed the free vibration modal equations of redundant shaking table, the modal matrix and its inverse matrix, the redundant vibration table consists of DOF space to space without the coupling mode in order to achieve the decoupling control, modal vibration control redundancy. At the same time through the analysis of the relationship between modal matrix and modal degree of freedom coupling characteristic, method of modal matrix experiments are given. The simulation analysis shows that compared with the decoupling control based on dynamic model, modal space decoupling control can effectively reduce the redundant shaking table the dynamic coupling between degrees of freedom. The X PC Target fast control prototype experimental system for control of redundant multi axis shaking table is developed based on the above The coupling characteristics and decoupling algorithm are analyzed and studied in detail. The experimental results verify the advanced and effective performance of the decoupling control strategy proposed in this paper.

【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：P315.8
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本文编号：1636426