车身顶棚振动独立模态控制研究

针对乘用车结构振动和噪声问题,对嵌入压电传感器和致动器的汽车顶棚进行了振动主动控制研究;对压电平板进行数学建模,通过有限元分析某国产乘用车车身顶棚模态振型,合理选择传感器和致动器增益,作为最小化振动响应这一目标函数的参数;控制器的设计应用了独立模态空间控制法,将压电传感器和致动器及独立模态空间控制法(IMSC)组成的控制系统应用于汽车顶棚振动主动控制,实验结果表明,即使当控制回路被电磁噪声干扰时,控制前后系统的振级相差可达到30%左右,取得了有效的振动抑制效果。     

基于压电陶瓷执行器的车削振动控制系统研究

针对车削加工时振动对加工精度的影响,设计了一种车削振动主动控制系统,系统控制器采用基于人工免疫系统的改进型反馈控制器,执行器采用压电陶瓷材料设计制作,建立压电陶瓷执行器和专用刀架传递函数模型,在Matlab环境下进行建模仿真,当振动频率在50～150Hz时仿真结果表明该控制系统能抑制振幅97%以上;另外进行了现场试验,以普通45#钢为车削工件,车削深度为0.07mm,在正常转速下对车削振动进行主动控制,结果证明设计的车削振动控制系统能抑制车削振动幅度37%以上。     

智能结构的压电片位置优化及主动控制研究

采用压电陶瓷作为作动器,对柔性结构的作动器位置进行了优化设计并对其进行了振动主动控制研究.首先分析了压电结构振动主动控制的原理和方法;采用基于作动器的模态影响矩阵对压电片进行了优化布置,使压电片配置在控制效能最优的位置.在存在噪声和干扰的情况下对智能结构进行控制,采用LQG/LTR和H∞方法对结构进行控制,并对二者的控制效果作了比较.结果显示在加入噪声和干扰后,进行适当的处理,采用LQG/LTR和H∞方法都能达到很好的控制效果,只是鲁棒性有差别.     

移动质量激励悬臂梁振动主动控制系统

利用压电材料的正逆压电效应,实现了移动质量激励悬臂梁振动主动控制;建立了压电元传感方程和作动方程,进一步将其转化为状态空间模型中的状态方程和输出方程;设计了基于线性二次型最优控制(LQR)策略的振动主动控制器,以TMS320VC33 DSP芯片为核心组建了相应的硬件电路。实验结果表明:采用压电自感作动器可很好地抑制移动质量激励引起的悬臂梁振动。     

智能太阳翼有限元建模与振动控制研究

采用空间梁单元和矩形层板单元建立了表面粘贴压电片太阳翼的机电耦合有限元模型．其中,太阳翼与星体之间的连接架、太阳翼基板间连接铰链按空间梁单元处理;不含压电片的太阳翼基板按普通层板单元处理,而含有压电片的基板按压电层板单元处理．推导了多点约束关系式处理空间梁单元和板单元公共节点自由度不协调的问题．利用速度负反馈和线性二次最优调节器设计控制系统,编制有限元分析程序,进行了动力学特性计算和振动控制数值仿真．结果表明,压电传感／作动器的引入对太阳翼振动频率具有重要影响;利用压电传感／作动器和最优控制系统能够有效抑制太阳翼的振动．     

车身结构与车内空腔流固耦合系统的模态分析

为研究汽车的振动噪声特性,利用ANSYS软件采用板壳、梁和流体单元建立某车身结构及车内空腔的有限元模型,其中,将车身结构作为弹性体,乘员室内的空气作为流体.通过对车身结构、车内空腔流体及车身与车内空腔流体的耦合结构进行模态分析,并对比计算结果,得到它们之间的相互关系,有利于整车振动和噪声特性的研究.     

电磁反力作动器控制系统设计

开发了一种采用电磁作动器的SPWM振动主动控制系统。简单介绍了电磁作动器的数学模型,通过仿真分析与试验分析了解了作动器的作动特性。阐述了SPWM的调制原理与频谱分析。对某中型货车发动机振动主动控制系统进行了控制规律研究,并应用单片机技术对控制系统进行了减振试验验证。结果表明发动机振动衰减明显,该振动主动控制系统的设计是可行的。     

基于声灵敏度的车身拓扑优化

为探讨板件结构对车内噪声的影响,建立某商务车的白车身有限元模型,分析其模态和车身声灵敏度,确定对汽车低频振动和噪声影响较大的板件;结合变密度法在整车环境下对板件进行减振降噪的拓扑优化,根据拓扑优化结果对板件进行结构修改. 优化后的车身声灵敏度曲线与原车身声灵敏度曲线相比,低频范围内的峰值都有不同程度的降低,表明结合整车动态响应的汽车板件结构拓扑优化可以有效降低车内低频振动噪声.     

基于超磁致致动器的车削振动主动控制

设计了一种基于模糊PID控制器和超磁致伸缩致动器的车削振动主动控制系统,推导了超磁致伸缩致动器和专用刀架的数学模型,并在Matlab环境下进行建模仿真,当振动频率在50~100Hz时,仿真结果表明该控制系统能抑制振幅达50%以上;在现场车削试验中,以普通45#钢为车削工件,分别在转速1 500r/min、车削深度为0.07mm和转速3 000r/min,车削深度为0.04mm下,对车削振动进行主动控制,结果证明所设计的车削振动控制系统能够抑制振动幅度达30%以上。     

柔性智能结构的振动主动控制仿真和实验研究

基于模态坐标表示的含压电片结构横向振动系统方程,采用独立模态法直接针对系统的高阶模型设计控制律,利用劳斯判据证明由所设计的控制器引起的控制溢出可被有效抑制,极大地降低了由于模型降阶引起的误差。同时,对压电柔性悬臂梁的高阶振动模态进行主动控制仿真模拟和实验研究,结果表明施加主动控制后柔性悬臂梁的模态阻尼显著提高,受控悬臂梁的振动得到了快速抑制。仿真计算和实验结果取得了良好的一致性。研究结果表明,利用压电陶瓷作为驱动元件,采用独立模态控制法实现柔性结构的振动抑制是一种高效的振动主动控制方法,在航天航空等领域中     

压电柔性机械臂的主动振动控制研究

针对柔性机械臂的振动问题,采用压电智能结构作为敏感器和驱动器进行主动控制.首先建立柔性机械臂的实验装置,其次对设计的柔性机械臂系统进行辨识研究,得到系统的前二阶模态频率,再次采用PD控制和PPF控制算法对柔性机械臂进行主动振动控制.实验结果表明,采用压电智能结构可以抑制柔性机械臂的振动,效果明显.     

Vibration Control of a Planar Parallel Manipulator Using Piezoelectric Actuators

This paper presents an active damping control approach applied to piezoelectric actuators attached to flexible linkages of a planar parallel manipulator for the purpose of attenuation of unwanted mechanical vibrations. Lightweight linkages of parallel manipulators deform under high acceleration and deceleration, inducing unwanted vibration of linkages. Such vibration must be damped quickly to reduce settling time of the manipulator platform position and orientation. An integrated control system for a parallel manipulator is proposed to achieve precise path tracking of the platform while damping the undesirable manipulator linkage vibration. The proposed control system consists of a PD feedback control scheme for rigid body motion of the platform, and a linear velocity feedback control scheme applied to piezoelectric actuators to damp unwanted linkage vibrations. In this paper, we apply the proposed vibration suppression algorithm to two different types of piezoelectric actuators and evaluate their respective performances. The two piezoelectric actuators are (i) a PVDF layer applied to the flexible linkage and (ii) PZT actuator segments also applied to the linkage. Simulation results show that both piezoelectric actuators achieve good performance in vibration attenuation of the planar parallel manipulator. The dynamics of the planar parallel platform are selected such that the linkages have considerable flexibility, to better exhibit the effects of the vibration damping control system proposed.     

压电作动器在基于声辐射模态的ASAC中的应用

控制作动器的选取和设计是实现主动结构声学控制的关键一环。利用压电材料的逆压电效应,选择矩形压电片作为控制作动器应用于基于声辐射模态的主动结构声学控制中,提出了基于声辐射模态的压电作动器主动控制策略,并得到了最佳控制电压的获取方法。以简支板为例,通过压电作动器控制效果分析,揭示了压电作动器控制的内在规律;通过与单点力控制效果的比较分析,验证了压电作动器控制策略的优越性。     

Self-learning active vibration control of a flexible plate structure with piezoelectric actuator

In this paper, an active vibration control (AVC) incorporating active piezoelectric actuator and self-learning control for a flexible plate structure is presented. The flexible plate system is first modelled and simulated via a finite difference (FD) method. Then, the validity of the obtained model is investigated by comparing the plate natural frequencies predicted by the model with the reported values obtained from literature. After validating the model, a proportional or P-type iterative learning (IL) algorithm combined with a feedback controller is applied to the plate dynamics via the FD simulation platform. The algorithms were then coded in MATLAB to evaluate the performance of the control system. An optimized value of the learning parameter and an appropriate stopping criterion for the IL algorithm were also proposed. Different types of disturbances were employed to excite the plate system at different excitation points and the controller ability to attenuate the vibration of observation point was investigated. The simulation results clearly demonstrate an effective vibration suppression capability that can be achieved using piezoelectric actuator with the incorporated self-learning feedback controller.     

Active noise control of flexible linkage mechanism with piezoelectric actuators

An active noise control method for flexible linkage mechanism systems with piezoelectric actuators and strain gauge sensors is studied. By employing a set of wave number transformations on the original equations of motion of the flexible linkage mechanisms, a new set of equations of motion is obtained, in which the unknown variables can describe the structural acoustic radiation level of the mechanism system directly. On the basis of the new equations, the active noise control of the flexible linkage mechanism system with piezoelectric actuators is discussed. Firstly, the optimal control forces are determined based on the optimal control theory. Secondly, the controller of the system that consists of the output feedback and the disturbance feed-forward control laws is presented. Simulations show that the method presented in this paper is valid.     

轿车动力总成主动隔振最优控制研究

介绍压电作动器与被动悬置串联组成的轿车动力总成主动悬置系统,分析了隔振系统的数学模型,采用最优控制原理提出了实施方法。     

Optimal design of dynamic absorbers on vibration and noise control of the fuselage

Optimum design of dynamic absorbers for reducing the vibration and the interior noise of an aircraft’s fuselage is studied. Herein, a thin, elastic cylindrical shell is adopted as a simple model of the fuselage. The sound source of the noise in the acoustic field comes from the vibration of the shell. Several dynamic absorbers are then attached to the shell for vibration and noise control. The vibration of the shell and its interior sound pressure, caused by the propellers or the engines are formulated. Optimum design of the absorbers is studied for obtaining the minimum vibration of the fuselage or the minimum noise level in the cylindrical cavity. From the numerical results, the absorbers are found to be effective for vibration and noise control of the fuselage. Some general guidelines on optimum absorber design are also offered in conclusion.     

Self-sensing actuators with passive damping for adaptive vibration control of hard disk drives

A push–pull piezoelectrically actuated devices have been developed for higher bandwidth servo systems as microactuators for fine and fast positioning, while the voice coil motor functions as a large but coarse seeking. However, the current dual-stage actuator design uses piezoelectric patches only and therefore a dual-stage servo system using enhanced active–passive hybrid micro piezoelectric actuators is proposed to improve the existing dual-stage actuators for higher precision and shock resistance, due to the incorporation of passive damping in the design. In this paper, three different configurations of self-sensing actuators (SSAs) incorporating an adaptive mechanism for vibration control of suspensions in dual-stage hard disk drives (HDDs) are investigated. In the piezo-based SSA configuration, the signal sensed due to mechanical deformation is mixed with the control input signal, which would be corrupted due to the variation of the piezoelectric capacitance when a fixed bridge circuit is used. In this study, a self-tuning adaptive compensation is used to combine with the SSA technique to extract the true sensing signal for the vibration control of suspensions in HDDs. An assembled suspension with piezoelectric microactuators is tested to demonstrate the vibration suppression performance of this adaptive structure under an external shock disturbance such as hammer excitation. The experimental results show that the target vibration modes have been suppressed effectively with using the adaptive positive position feedback controller for the enhanced SSAs with passive damping in HDDs.     

采用MFC压电作动器对复合材料悬臂板振动主动控制

针对复合材料层合悬臂板,在其上表面铺设压电纤维复合材料MFC作为作动器,同时在下表面对称铺设压电薄膜(PVDF)作为传感器,应用速度反馈控制方法研究其主动振动控制.运用Hamilton原理和假设模态法推导含多个MFC作动器的复合材料层合板的力电耦合结构运动方程,其中考虑了MFC作动器作为悬臂板附加质量及刚度的影响.基于模态控制力/力矩最大化的原则,将多对MFC作动器/PVDF传感器铺设在层合悬臂板前几个低阶模态应变最大的区域,通过算例得出结构受控前后的时域和频域响应以及各MFC作动器所需的控制电压曲线.讨论复合材料层合板纤维铺设角度不同情况下,作动器MFC铺设位置及压电纤维铺设方向的相应变化.