【作者】 李锋；

【导师】 杨铁军；

【作者基本信息】 哈尔滨工程大学 ， 轮机工程， 2024， 博士

【摘要】 船舶机械设备主动减振技术是抑制船用大型机械设备低频振动传递的一种有效手段,经过数十年的发展,已经逐渐走向工程应用。在进行主动减振系统设计时,不论是采用经典还是现代控制理论,都必须获取被控对象的动力学特性,其中从控制器输出到误差传感器输出之间的次级通道的频响特性尤为重要,是控制系统设计的重要依据。对于船舶大型机械设备主动减振系统而言,由于被控对象复杂的结构形式和边界条件,很难通过数学建模得到次级通道的参数模型,通常采用基于输入和输出信号的系统辨识方法获取次级通道的频响特性,但这种辨识方法只有在整个主动减振系统完成设计和安装后才能进行。而主动减振系统设计过程中需要考虑作动器与被控对象的阻抗是否匹配、进行控制系统的仿真和效果评估以优化系统方案设计,均需要次级通道才能方便地进行建模和方案修改。这些在实验室中简单易行的操作对于船舶大型机械设备主动减振系统的安装现场却极其不便。针对上述问题,本文提出一种基于次级通道预辨识的船舶大型机械设备主动减振系统设计方法。该方法通过专门研制的便携式激振设备获得现场被控对象作动器与误差传感器安装位置之间的传递函数,结合安装现场外获得的其他环节(如作动器等)的辨识结果构造出完整的次级通道预辨识模型,最终借助该模型进行主动减振系统设计,优化控制方案,提升控制系统性能,提高现场工作效率。为保证次级通道预辨识结果的准确性,首先对影响各环节频响特性的主要因素进行分析。通过建立包含作动器安装位置原点导纳的动力学模型,对安装基础的影响进行分析,证明辨识过程中可以忽略基础的影响。通过分析输入电压对次级通道各环节的影响,确定不同环节对电压变化的敏感程度,探究电压变化对预辨识结果的影响。通过分析模数和数模转换器的频响特性,得到该环节对于整体次级通道的影响规律,并提出相应的补偿方法,提高预辨识方法的适用性。研制了一种专门用于船舶大型机械设备主动减振系统作动器安装位置到误差传感器安装位置之间结构路径辨识的气动式冲击锤(简称气锤)。通过建立气体做功过程的热-机耦合模型和活塞减速过程的运动模型,研究不同进气压力下活塞到达最大速度所需的行程长度,分析冲击初速度、锤头材质、锤头直径和活塞质量对于冲击结果的影响。对比分析将力传感器布置在活塞上和安装法兰下所测结果的异同,确定力传感器的最优布置方案,并对气锤的可重复性进行验证。以多输入单输出系统描述作动器对被控对象的作用机理,分析作动器底板几何参数、锤击位置和线圈位置等因素对于结构路径的影响,并基于分析结果提出针对线圈上置型作动器结构路径的建模方法,同时验证该方法对于多通道控制系统的可行性。以船舶大型机械设备的主动减振联调台架作为目标系统进行主动减振系统设计。采用预辨识方法得到了系统次级通道的预辨识模型,并与传统的离线辨识模型对比验证了其准确性。基于次级通道的预辨识模型进行主动减振仿真和试验,验证直接将预辨识模型代替实际次级通道模型的主动减振试验的可行性,对比基于次级通道预辨识模型的主动减振仿真结果与实际控制结果,探究将基于预辨识模型仿真得到的控制器权向量作为实际系统控制器初值和直接作为控制器权值的主动减振试验的控制效果,以及验证通过预辨识模型确定次级通道模型的合理阶次的可行性。通过与基于传统离线辨识次级通道的主动减振仿真和试验对比,验证本文提出的基于次级通道预辨识的主动减振系统设计方法的可行性和有效性。更多还原

【Abstract】 Active vibration control(AVC)technology,which has gradually been put into practice after decades of development,is an effective method to reduce the low-frequency vibration transmission of large-scale machinery equipment in marine applications.In the design stage of an AVC system,it is necessary to know the dynamic characteristics of the structure to be controlled regardless of adopting a classical or modern control theory.Frequency response characteristics of the secondary path between the outputs of the controller and error sensor are particularly important,and act as the foundation of an AVC system design.For an AVC system of large-scale marine mechanical equipment,it is difficult to obtain the parametric model of the secondary path through mathematical modeling due to the complex structure and boundary conditions.The system identification method based on input and output signals is more commonly applied,even though it can only be carried out after the whole AVC system has been completed.In the design stage of an AVC system,it is necessary to consider the impedance match between actuators and structure to be controlled,system simulations and performance evaluation.The secondary path model is essential for system modeling and modification.This kind of operations are simple and easy in the laboratory,but extremely inconvenient for an active vibration control system for large marine mechanical equipment on board.To solve the above problems,a design method for the AVC system based on secondary path pre-identification is proposed in this thesis.The transfer function of the structure to be controlled between the actuator and error sensor’s positions is measured by a specially developed portable excitation device,and then combined with the modeling results of rest parts(for example actuators)obtained in the laboratory to construct a complete secondary path model.Finally,the AVC system is designed based on this model to optimize the control strategy,improve the performance of the control system,and raise the experimental work efficiency onsite.To ensure the accuracy of the pre-identification results,the main factors affecting the frequency response characteristics of each part are analyzed firstly.By establishing a dynamic model including the point mobilities of the controlled structure where the actuators are possibly located,the influences of the foundation dynamic behavior on the pre-identification are studied,and the results show that the dynamic of the foundation structure can be ignored in the identification process.The sensitivity of each part to input signal is determined by changing the input signal magnitude,and the influence of the input signal on the pre-identification results is investigated.By analyzing the frequency response characteristics of analog-to-digital and digital-to-analog converters,the influence of these parts on the secondary path are obtained,and the corresponding compensation methods are proposed to improve the applicability of the pre-identification method.A pneumatic impact hammer is specially developed to identify the structural path between the actuator and the error sensor of an AVC system for large-scale marine mechanical equipment.By establishing the thermo-mechanical coupling model of the gas doing work process and the motion model of the piston deceleration process,the stroke required for the piston to reach the maximum speed under different inlet pressures is studied.The influences of the initial impact velocity,material and diameter of the hammer head,and mass of the piston on the impact results are analyzed.By comparing the results measured by the force gauge installed in series with the hammer head and under the flange respectively,the optimal arrangement of the force gauge is determined.Then the repeatability of the pneumatic impact hammer is verified.The actuating mechanism between the actuator and the structure to be controlled is described as a multi-input single-output system,and the influences of the factors,such as geometric parameters of the bottom plate,the excitation position of the hammer,and the installation position of the coil,on the structural path are analyzed.Based on the results,a modeling method for the structural path including the actuator with the coil being installed on its top plate,is proposed.The feasibility of the pre-identification method for the multi-channel AVC system is verified.An AVC system bench for the marine large-scale mechanical equipment in laboratory is assumed as a real ship system on board to be designed.The pre-identification model of secondary path is compared with the traditional off-line identification results to verify its correctness.The active vibration control simulation and experiments are conducted based on the pre-identification secondary path model,including active vibration control simulation and experiment by using the secondary path pre-identification model directly,the active vibration control experiments by adopting the simulation controller vector as the initial value and the final value respectively,and determining a reasonable order of the secondary path model by the pre-identification model.The results are compared with which from the active vibration control simulation and experiments based on the traditional off-line identification model.The comparison shows the feasible and effectiveness of the proposed AVC system design method for large marine mechanical equipment based on the pre-identification model of secondary path.更多还原