自适应逆控制在振动试验装置中的应用

发布时间：2018-04-09 07:50

本文选题：多轴电液振动台　切入点：时域波形复现　出处：《哈尔滨工业大学》2017年硕士论文

【摘要】：多轴电液振动台作为一种基础的力学环境模拟实验设备,通过复现期望的加速度波形,从而在实验室中模拟真实的振动环境,进而研究试件的疲劳寿命和可靠性,被广泛应用于土木、交通、军工、航空航天和精密仪器等行业。在工程技术领域,提高这种设备的时域波形复现精度成为研究的热点。自适应逆控制作为一种先进的控制策略,被认为是多轴电液振动台控制领域的发展方向。本文在哈尔滨工业大学电液伺服仿真与试验系统研究所承担的国家自然科学基金资助项目“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”(51205077)支持下,对基于自适应逆控制的多轴电液振动台控制策略进行深入研究。本文首先研究多轴电液振动台的伺服控制系统,其组成以三状态控制策略为核心,结合自由度独立控制器和压力镇定控制器;在考虑液压执行机构流量非线性的基础上建模并推导三状态控制策略的参数整定规则。仿真结果验证了这种振动控制系统可以拓展振动台加速度闭环传函的频宽并提高系统稳定性。但这种伺服控制系统存在时域波形复现精度不高和参数整定复杂繁琐的缺陷。在前述伺服控制系统的基础上,本文采用了基于自适应逆控制的振动控制策略以提高时域波形复现的精度。本文首先分析自适应逆控制的组成及其核心——自适应滤波算法;从离线和在线两个方面给出了自适应逆控制在工程中应用的形式,并归纳应用时的技术难点。针对该算法时域传函辨识环节中存在的最优阶数确定难题,本文采用一种变阶数NLMS自适应滤波算法离线辨识最优阶数。针对离线自适应逆控制受传函辨识精度限制存在较大误差的问题,本文采用基于BP神经网络的自适应滤波算法进行改进。仿真分析验证了该算法以及提出的改进措施可以有效地提高时域波形复现的精度。基于三状态控制策略的伺服控制系统,采用三状态前馈补偿振动台位置闭环传函的传递特性,补偿效果不佳且参数整定复杂。本文基于离线自适应逆控制算法设计电液振动台位置闭环逆传函以代替三状态前馈。这种改进的三状态控制策略不仅减少了一半待整定参数,而且优化了系统的传递特性。在该策略的基础上,本文结合X-滤波在线自适应逆控制提出一种综合自适应逆控制策略,既有较少的待整定参数,又进一步提高了时域波形复现的精度。仿真结果证明了本文研究工作的有效性。本文在多轴电液振动台上通过实验与分析比较验证了研究工作的先进性。
[Abstract]:As a basic mechanical environment simulation experimental equipment, the multi-axis electro-hydraulic shaking table simulates the real vibration environment in the laboratory by reproducing the desired acceleration waveform, and then studies the fatigue life and reliability of the specimen.Widely used in civil engineering, transportation, military industry, aerospace and precision instruments and other industries.In the field of engineering technology, improving the accuracy of time-domain waveform reproduction of this equipment has become a hot spot.As an advanced control strategy, adaptive inverse control is considered as the development direction of multi-axis electro-hydraulic shaking table control field.This paper is supported by the Research Institute of Electro-hydraulic Servo Simulation and Test system of Harbin University of Technology (Harbin University of Technology), which is supported by the National Natural Science Foundation of China, "study on the Mechanism of Internal Force Coupling and its suppression method of Ultra-redundant parallel driving Seismic Simulation Station" 51205077.The control strategy of multi-axis electro-hydraulic shaking table based on adaptive inverse control is studied.In this paper, the servo control system of the multi-axis electro-hydraulic vibration table is studied. The three-state control strategy is the core of the servo control system, which combines the independent controller with the degree of freedom and the pressure stabilization controller.On the basis of considering the nonlinear flow of hydraulic actuator, the parameter tuning rules of three state control strategy are deduced.The simulation results show that the vibration control system can extend the frequency width of the closed-loop function of vibration table acceleration and improve the stability of the system.However, this servo control system has some shortcomings such as low precision of waveform reproduction in time domain and complicated parameter tuning.On the basis of the servo control system mentioned above, the vibration control strategy based on adaptive inverse control is adopted to improve the precision of waveform reproduction in time domain.In this paper, the composition of adaptive inverse control and its kernel, adaptive filtering algorithm, are analyzed firstly, the application forms of adaptive inverse control in engineering are presented from both offline and online aspects, and the technical difficulties in application are summarized.In order to solve the problem of determining the optimal order in the identification of time-domain function, a variable order NLMS adaptive filtering algorithm is used to identify the optimal order off-line in this paper.In order to solve the problem that the accuracy of off-line adaptive inverse control is limited by the function identification, the adaptive filtering algorithm based on BP neural network is improved in this paper.The simulation results show that the proposed algorithm and the improved measures can effectively improve the accuracy of time domain waveform reproduction.The servo control system based on three-state control strategy uses three-state feedforward compensation to compensate the transfer characteristic of the position closed-loop function of the shaking table. The compensation effect is not good and the parameter tuning is complex.In this paper, an off-line adaptive inverse control algorithm is used to design a closed-loop inverse function for the position of an electro-hydraulic shaking table instead of a three-state feedforward.The improved three-state control strategy not only reduces the parameters to be adjusted by half, but also optimizes the transfer characteristics of the system.On the basis of this strategy, an integrated adaptive inverse control strategy based on X- filtering online adaptive inverse control is proposed, which not only has less parameters to be adjusted, but also improves the precision of waveform reproduction in time domain.The simulation results show the effectiveness of the research work in this paper.In this paper, the advanced nature of the research is verified by experiment and analysis on the multi-axis electrohydraulic vibration table.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB53;TP273

【参考文献】