空间柔性天线展开臂的半主动振动控制研究

大型柔性天线展开臂结构由于其尺寸大,阻尼和刚度小,其振动呈现明显的低频特性,且很难在短时间内迅速衰减,从而影响天线工作性能。传统的被动控制大都采用阻尼材料,通过增加阻尼的方法来进行控制,这种控制方法对低频柔性结构的控制效果是有限的。因此研究带负载的复合材料柔性展开臂结构的振动抑制问题,提出用压电元件粘贴在展开臂结构表面作为传感器和驱动器,用基于同步开关阻尼技术的自适应半主动振动控制方法控制压电驱动器,从而对展开臂结构实现振动控制。完成了展开臂模型的建立和仿真分析,建立了展开臂结构的开关阻尼半主动控制试验平台,设计并制作了控制电路,针对需要控制的结构一阶弯曲模态进行压电元件的合理布设。对不同激励下的振动进行了展开臂结构的控制试验,试验结果显示该方法对带负载柔性天线展开臂结构的振动具有良好的抑制效果,对于初始位移为100 mm的瞬态激励振动工况,受控系统等效阻尼比由0.6%增加至4.03%;对于稳态振幅为50 mm的稳态振动工况,系统控制后结构端部振动幅值降低至10 mm,稳态振动幅值降低了16.843 dB。在大型柔性结构中具有非常好的应用前景。     

基于车载导航的半主动悬架路况协调控制

难以获得路况信息是影响半主动悬架控制性能的重要因素。进行了依据车载导航系统探测和记忆路况信息,半主动悬架据此信息提前切换到相应控制策略或阻尼的初步研究。设计了半车天棚控制器,在随机路面采用天棚控制,当导航仪探测到前方障碍时,则提前通知悬架控制器切换到小阻尼状态,从而降低振动的峰值,提高行驶的平顺性。仿真计算证明了这种思路的有效性。研制了车载导航系统并设计了路况等级探测和记忆查找的策略,实车试验取得了和仿真相近的效果。     

机械臂与环境交互的位置/力切换抑制振动方法

当机械臂执行位置/力的混合跟踪任务时，位置控制一般用于机械臂的自由运动阶段，力控制一般用于约束运动阶段。这种位置/力切换的控制结构既能实现与环境接触前对机械臂位置的精确控制，也能保证接触后对期望控制力的准确跟踪。由于开关系统本身存在的切换不稳定性，机械臂在以一定的速度与环境接触时，机械臂执行器会在环境表面振动甚至弹跳。针对此问题，提出了一种半主动阻尼阻抗学习方法，该方法主要包含两部分：基于位置/力切换控制的半主动阻尼控制器；基于一种逆秩拟牛顿法（broyden fletcher goldfarb shanno，简称BFGS）的阻抗学习算法，根据学习到的环境参数调节半主动阻尼，实现机械臂在接触面的振动抑制和平稳过渡。在仿真及实验中，应用提出的方法让机械臂与不同环境交互，结果表明：该方法能很好地抑制接触过渡阶段的超调力，并防止机械臂在切换过程中的振动，实现了柔顺接触和平稳过渡。     

Fuzzy-PID切换控制在磁流变半主动悬置系统中的应用

建立了一种新型动力总成磁流变悬置的动力学模型,并对其进行动态特性试验。通过数值拟合方法对试验数据进行拟合,得到了电流与可控阻尼力的关系式,为磁流变悬置的控制应用提供了理论模型。考虑车辆悬架系统的等效刚度和阻尼,建立了磁流变半主动悬置系统模型。设计了磁流变半主动悬置Fuzzy-PID切换控制系统,对不同工况下磁流变半主动悬置系统的隔振特性进行了仿真研究,结果表明应用Fuzzy-PID切换控制的磁流变半主动悬置系统具有良好的隔振效果。     

高速列车弹性车体垂向振动控制

建立包含车体弹性的高速列车单车刚柔耦合动力学模型.针对车体垂向振动,分别在一系悬挂和二系悬挂系统中采用半主动控制策略,研究控制策略对车辆运行平稳性的影响.结果表明,二系天棚阻尼半主动控制与二系阻尼连续可调型半主动控制均能有效降低车体低频处的刚性振动,相对而言,前者对于低频振动抑制效果更佳,但对较高频率的弹性振动无明显作...     

半主动振动控制系统中的模拟开关控制电路

在压电振动控制方法中,针对主、被动振动控制中的不足,同时为了降低系统功耗、减小振动控制系统体积,介绍了一种基于同步开关阻尼技术的半主动振动控制方法。由运算放大器构成模拟开关控制电路,利用简单的相位延迟方法,实现对输入信号的极值判断,从而实现对开关电路的控制。     

汽车半主动悬架的多目标优化设计

提出了一种多目标优化设计汽车半主动悬架的方法，以车身加速度和轮胎动力的积分作为优化设计目标，选择阻尼系数、半主动阻尼控制逻辑、采样频率作为优化参数，利用德国宇航院(DLR)开发的控制系统的分析设计软件(ANDECS)对二类半主动阻尼器(即开关型和连续型)进行了研究，以一个受半正弦波激励的四分之一汽车模型为例比较各类被动、半主动和主动悬架的减振效果，证实本设计算法的减振效果。     

基于模糊逻辑推理的风机塔筒半主动控制

采用基于模糊逻辑推理的半主动控制技术对风机塔筒进行风致振动控制,通过对塔筒结构实时的动力响应进行模糊逻辑推理,利用半主动控制算法调节调频质量阻尼器(Tuned Mass Damper,TMD)的阻尼系数,输出不同的阻尼力,对塔筒结构进行振动控制。通过Simulink软件进行半主动模糊控制系统仿真,结果表明,基于模糊逻辑推理的半主动控制比传统被动控制的控制效果更好,可以大幅降低塔筒结构顶端的位移响应。     

汽车原地换挡时半主动液压阻尼拉杆设计方法

为减小自动档汽车在原地换挡时由于变速箱的扭矩扰动产生的冲击与振动,提出了汽车原地换挡时半主动液压阻尼拉杆（hydraulic damping strut,简称HDS）的设计分析方法。首先,对原地换挡的冲击与振动机理进行了理论分析;其次,构建了汽车原地换挡时的动态响应评价指标,建立了包含半主动液压阻尼拉杆的整车13自由度（degrees of freedom,简称DOFs）动力学模型,根据力分担的方法对半主动HDS的动态特性参数进行了优化分析;最后,采用整车13自由度动力学模型对汽车原地换挡时加半主动HDS和不加半主动HDS时的动态响应评价指标进了分析,并通过试验对座椅导轨的加速度进行了测试。研究结果表明,加入半主动HDS减小了汽车原地换挡时的冲击与振动。     

基于模糊控制的高速列车半主动减振器研究

装有被动减振器的列车在时速大于200km的高速运行条件下，振动性能恶化。采用半主动减振器后，通过对减振阻尼系数的实时调整，可改善高速列车运行时的动力学性能。采用高速开关阀来控制的半主动减振器，运用模糊控制策略动态地确定车辆运行时的阻尼值，并通过PWM控制方式实现阻尼的调节。这种新型减振器具有减振力调节方便，控制实时性好，结构相对简单的优点。     

Semi-active vibration control using piezoelectric actuators in smart structures

The piezoelectric materials, as the most widely used functional materials in smart structures, have many outstanding advantages for sensors and actuators, especially in vibration control, because of their excellent mechanical-electrical coupling characteristics and frequency response characteristics. Semi-active vibration control based on state switching and pulse switching has been receiving much attention over the past decade because of several advantages. Compared with standard passive piezoelectric damping, these new semi-passive techniques offer higher robustness. Compared with active damping systems, their implementation does not require any sophisticated signal processing systems or any bulky power amplifier. In this review article, the principles of the semi-active control methods based on switched shunt circuit, including state-switched method, synchronized switch damping techniques, and active control theorybased switching techniques, and their recent developments are introduced. Moreover, the future directions of research in semi-active control are also summarized.     

Vibration Control of a Composite Beam Using Self-sensing Semi-active Approach

Structural vibration control was an active research area for the past twenty years because of their potential applications in aerospace structures,civil structures,naval structures,etc.Semi-active vibration control methods based on piezoelectric actuators and synchronized switch damping on inductance(SSDI) techniques attract the attention of many researchers recently due to their advantages over passive and active methods.In the SSDI method,a switch shunt circuit is connected to the piezoelectric patch to shift the phase and amplify the magnitude of the voltage on the piezoelectric patch.The most important issue in SSDI method is to control the switching actions synchronously with the maximum vibration displacement or maximum strain.Hence,usually a displacement sensor is used to measure the vibration displacement or a collocated piezoelectric sensor is needed to measure the strain of the structure near the piezoelectric actuator.A self-sensing SSDI approach is proposed and applied to the vibration control of a composite beam,which avoids using a separate sensor.In the self-sensing technique,the same piezoelectric element functions as both a sensor and an actuator so that the total number of required piezoelectric elements can be reduced.One problem in the self-sensing actuator,which is the same as that in the traditional collocated piezoelectric sensors,is the noise generated in the sensor signal by the impact of voltage inversion,which may cause extra switching actions and deteriorate control performance.In order to prevent the shunt circuit from over-frequent on-and-off actions,a simple switch control algorithm is proposed.The results of control experiments show that the self-sensing SSDI approach combined with the improved switch control algorithm can effectively suppress over-frequent switching actions and gives good control performance by reducing the vibration amplitude by 45%,about 50% improvement from the traditional SSDI with a separate piezoelectric element and a classical switch.     

Effect of boundary (support) conditions on piezoelectric damping in the case of SSDI vibration control technique

Piezoelectric transducers in conjunction with appropriate electric networks can be used as a mechanical energy dissipation device. If a piezoelectric element is attached to a structure, it is strained as the structure deforms and converts a portion of the vibration energy into electrical energy that can be dissipated through a shunt network in the form of heating. These vibration control devices experienced a great development in recent years, due to their performances and advantages compared with active techniques. One of them is the synchronized switch damping (SSD) and derived techniques, which were developed in the field of piezoelectric damping, and which lead to a very good trade-off between the simplicity, the required power supply and their performances. This technique consists in a non-linear processing of the piezoelectric voltage, which induces an increase in electromechanical energy conversion. The control law consists in triggering the inverting switch on each extremum of voltage (or displacement). In this study, the proposed method for the switching sequence is based on the statistical evaluation of structural deflection. The purpose of this paper is to present an experimental study of the synchronized switch damping on inductance (SSDI) control technique sensitivity to the system boundary conditions. It is observed that the fundamental natural frequency greatly depends on these conditions. The effect of these constraints is distributed all over the system and significantly affects the results.     

车辆电动静液压作动器的半主动悬架时滞补偿控制

为了改善车辆行驶的平顺性和操纵稳定性,设计了一种基于电动静液压作动器（EHA）的车辆半主动悬架结构。进行了EHA作动器的性能试验分析,建立了EHA半主动悬架的键合图模型,计算了EHA半主动悬架系统的临界时滞,分析了时滞对EHA半主动悬架幅频特性和减振性能的影响,设计了Smith预估时滞补偿控制器,进行了EHA模糊控制半主动悬架的时滞补偿仿真分析。结果表明,EHA半主动悬架具有较好的阻尼可控性;然而随着时滞的增大,悬架系统会出现“轮跳”现象;在Smith时滞预估补偿控制下,EHA半主动悬架的簧载质量加速度减小约30%,轮胎动载荷减小约20%。     

馈能磁流变半主动悬架模糊滑模控制

为优化悬架减振性能和馈能性能,提出了一种馈能磁流变减振器结构,并设计了相应的半主动悬架模糊滑模控制策略。建立了磁流变减振器力学模型和馈能模型,以及相应的二自由度半主动悬架系统数学模型。针对半主动悬架系统的不确定性,基于混合天地棚阻尼控制系统,设计了滑模变结构控制器。使用饱和函数缓解系统抖振,并运用模糊控制优化滑模控制器。用谐波叠加法生成路面激励输入,分别对被动悬架、基于混合天地棚阻尼控制的半主动悬架以及基于模糊滑模控制的半主动悬架进行对比仿真。结果表明：基于模糊滑模控制的半主动悬架减振性能更好,能耗更小,且有良好的馈能性能,验证了馈能磁流变减振器结构的可行性和模糊滑模控制策略的有效性。     

半主动直接输出反馈变结构控制电流变阻尼器减振研究

针对多层结构电流变阻尼器减振系统运动状态难以完全实时测量、扰动存在不确定性、系统参数容易出现摄动以及阻尼器连续可调的特点,提出了半主动直接输出反馈变结构控制策略,根据滑模运动方程稳定的Hurwitz判据选择滑模梯度参数,实现控制与扰动完全解耦;饱和非线性环节使阻尼器阻尼力不超调;阻尼力对主结构做负功控制规则保证主结构最佳减振。仿真分析表明,电流变阻尼器减振控制系统效果明显,不仅对扰动具有自适应性,而且对系统参数摄动也具有很强的鲁棒性。     

A road-adaptive control law for semi-active suspensions

This paper presents a road-adaptive control law for semi-active vehicle suspensions. In semi-active suspensions, damping coefficients are controlled so as to make the actual damper force as close to the desired damper force as possible at any time instance. The proposed control law consists of a road-adaptive sky-hook damping algorithm and a Road Detection Algorithm (RDA). This approach leads to the sprung mass and unsprung mass velocity feedback control law with time varying gains. The gains are tuned by the RDA. To evaluate the performance enhancement brought about by the proposed control law, the performance of a semi-active suspension with the proposed control law is compared to those of the sky-hook controlled semi-active suspension and a passive suspension. The controller has been implemented experimentally on a quarter car test rig and a semi-active damper with a 19 damping rates has been used to generate the desired semi-active force. The proposed control law provides adequate damping for the wheel hop frequency and improved performance compared to that of the sky-hook control law.     

SEMI-ACTIVE CONTROL OF VEHICLE SUSPENSION WITH MAGNETO- RHEOLOGICAL DAMPERS： PART Ⅰ ——CONTROLLER SYNTHESIS AND EVALUATION

A modified skyhook-based semi-active controller is proposed for implementing an asymmetric control suspension design with symmetric magneto-rheological （MR） dampers. The controller is formulated in current form, which is modulated by integrating a continuous modulation and an asymmetric damping force generation algorithms, so as to effectively minimize switching and hysteretic effects from the MR-damper. The proposed controller is implemented with a quarter-vehicle MR-suspension model, and its relative response characteristics are thus evaluated in terms of defined performance measures under varying amplitude harmonic, rounded pulse and random excitations. The sensitivity of the semi-active suspension performance to variations in controller parameters is thoroughly evaluated. The results illustrate that the proposed skyhook-based asymmetric semi-active MR-suspension controller has superior robustness on the system parameter variations, and can achieve desirable multi-objective suspension performance.     

SEMI-ACTIVE CONTROL OF VEHICLE SUSPENSION WITH MAGNETO- RHEOLOGICAL DAMPERS: PART Ⅰ-CONTROLLER SYNTHESIS AND EVALUATION

A modified skyhook-based semi-active controller is proposed for implementing an asymmetric control suspension design with symmetric magneto-rheological (MR) dampers. The controller is formulated in current form, which is modulated by integrating a continuous modulation and an asymmetric damping force generation algorithms, so as to effectively minimize switching and hysteretic effects from the MR-damper. The proposed controller is implemented with a quarter-vehicle MR-suspension model, and its relative response characteristics are thus evaluated in terms of defined performance measures under varying amplitude harmonic, rounded pulse and random excitations. The sensitivity of the semi-active suspension performance to variations in controller parameters is thoroughly evaluated. The results illustrate that the proposed skyhook-based asymmetric semi-active MR-suspension controller has superior robustness on the system parameter variations, and can achieve desirable multi-objective suspension performance.     

双面抛光机上研磨盘振动抑制的半主动控制方法

振动是影响超精密加工质量的关键因素之一,弹簧加压式双面抛光机在抛光过程中的上研磨盘振动现象严重制约了产品的加工精度。为解决这一问题,提出了在弹簧加压装置中加入磁流变阻尼器的方法,通过控制磁流变阻尼器阻尼系数来实现对双面抛光和上研磨盘振动的半主动控制,以达到抑制振动的效果。首先,对改进后的压力加载系统进行了数学建模,得到了抛光过程中上研磨盘的运动方程式;接着,对半主动控制的控制策略进行了设计,得到了其控制算法;最后,在Simulink中对半主动控制策略下的系统进行了仿真分析,并将其仿真结果与未加控制时的系统仿真结果进行了比较分析。比较分析结果表明,所设计的半主动控制方法能够有效抑制双面抛光机上研磨盘的振动现象。