时变质量梁系统的振动主动控制研究

为了保证机械臂运动的高精度、准定位,采用主动控制技术降低结构的干扰振动是一项迫切而紧急的任务。该文以含变质量构件的弹性梁系统为对象,开展变质量弹性结构的振动特性研究和振动主动控制研究。使用模态叠加法推导了粘贴有压电片的变质量-柔性梁组合结构的控制方程,通过仿真获得变质量弹性梁系统的振动特性和运动规律。然后设计反馈控制器对质量增大系统和质量减小系统进行了振动主动控制,并采用时频分析技术分析了控制效果。仿真结果表明,变化的质量在引起系统振动频率改变的同时,还引起了一个附加的阻尼。在变质量时变系统的共振频率区间,通过反馈控制可有效抑制结构的振动。     

压电膜在振动控制中的应用及有限元分析

介绍了压电现象的基本原理及其在柔性结构主动减振中的应用，回顾了以往有限元法用于柔性结构振动主动控制分析的主要研究工作，提出了今后需要解决的问题。     

柔性梁振动主动控制的压电控制技术研究

采用压电陶瓷片作为传感器和地器对柔性梁振动传感和控制。分析了振动感和能量消耗控制方法的原理,并根据实际情况对传感信号进行了必要的处理以保证控制的稳定性和有效性,从实验结果来看,达到了比较明显的减振效果,为今后深入研究太空机敏柔性结构的振动主动控制奠定了良好的基础。     

基于ARX模型的压电智能结构振动预测控制

采用预测控制法对压电智能结构的振动主动控制进行了实验研究，通过实验方法建立了系统的ARX模型，并在此基础上设计了预测控制器对结构进行振动主动控制。实验结果验证了该方法在压电智能结构振动主动控制中的可行性和有效性。     

应用相敏光放大克服光孤子传输系统中Gordon-Haus限制的研究

通过计算机系统仿真研究了应用相敏光放大器(PSA)作为在线放大器的光孤子传输系统，并与相应的掺铒光纤放大器(EDFA)光孤子系统作了比较。仿真了平均孤子和动态孤子两种传输方案．研究结果表明，由于PSA不存在ASE噪声，应用PSA作为在线放大器可以克服光孤子系统中的Gordon-Haus限制．对平均孤子，在没有附加其它的孤子控制技术的情况下，PSA系统孤子的稳定传输距离得到极大的延长．对动态孤子，PSA亦表现出良好的抑制脉冲展宽效果，但脉冲的幅度经长距离传输后显著下降．     

压电减振机敏柔性板上的布片位置优化研究

将Ｄ优化法推广应用于二维悬臂机敏柔性板上的压电传感／执行器的位置优化研究中,并用实验证明了该方法的合理性,为进一步深入开展机敏柔性板的振动主动控制奠定了良好的基础。     

环境温度变化压电智能骨料信号稳定性试验研究

研究了压电智能骨料在环境温度变化时的信号稳定性问题,并明确其变化规律及分析原因,为基于压电智能骨料的混凝土结构健康监测奠定基础。将预先埋设压电智能骨料的小尺寸素混凝土梁置入恒温试验箱中,改变箱内温度并记录不同温度下的压电智能骨料信号能量值,利用试验数据拟合出信号能量值与温度之间的关系。试验结果表明,压电智能骨料信号幅值受温度影响变化明显且表现出明显的非线性变化规律及符合压电材料机电耦合系数随温度变化的规律,其原因是由于压电陶瓷材料本身弹性常数随温度变化,并在宏观上体现为机电耦合系数的变化。     

Integral resonant damping for high-bandwidth control of piezoceramic stack actuators with asymmetric hysteresis nonlinearity

This paper presents a novel control scheme for high-bandwidth control of piezoceramic stack actuators (PSAs). For this purpose, we first characterize and compensate for the asymmetric hysteresis nonlinearity of the PSA. A linear integral resonant controller is then designed as a means for damping the resonant modes of the dynamic system with the hysteresis compensation. Finally, a tracking controller and feedforward input are developed to minimize the tracking errors and improve the closed-loop tracking bandwidth. To verify the effectiveness and efficiency of the proposed control scheme, a PSA-actuated positioning platform is built and comparative experiments are conducted. Experimental results demonstrate that the proposed controller achieves robust broadband nanopositioning of the PSA by improving the tracking bandwidth from 22 Hz (with an integral controller) to 657 Hz.     

Experimental parameters identification of a flexible rotor system equipped with smart magneto-rheological bearing

Magnetorheological (MR) fluid is one of the most effective smart fluids with controllable rheological and viscoelastic properties that is used in semi-active vibration control of systems and structures. MR squeeze-film dampers (MRSFDs) are categorized among smart bearings with variable stiffness and damping properties, which enable vibration mitigation of rotary systems. In this aspect, precise modeling of the rotor systems equipped with MRSFDs and identifying their parameters are of paramount importance for analyzing the vibration behavior of the system and developing control strategies. The present study aims to present the analytical tools and algorithms for identifying the parameters of flexible rotor systems equipped with MRSFDs. For this purpose, a rotor-bearing system test setup including a flexible rotor, two ball bearings, an MRSFD, and an unbalanced disk is designed and fabricated, and its governing equations of motions are derived using finite element (FE) methods. The parameters of the flexible rotor system, as well as the stiffness and damping coefficients of the bearings and nonlinear damping forces of the MRSFD, are then identified using the developed algorithm and the harmonic responses of the system as its input. The procedure is then validated by comparing the results of the FE model with identified parameters with those measured experimentally. It is shown that the developed algorithm and FE model are capable of accurately identifying the parameters of the flexible rotor-bearing system equipped with an MRSFD.     

Intelligent optimal control of single-link flexible robot arm

This paper addresses the design and properties of an intelligent optimal control for a nonlinear flexible robot arm that is driven by a permanent-magnet synchronous servo motor. First, the dynamic model of a flexible robot arm system with a tip mass is introduced. When the tip mass of the flexible robot arm is a rigid body, not only bending vibration but also torsional vibration are occurred. In this paper, the vibration states of the nonlinear system are assumed to he unmeasurable, i.e., only the actuator position can be acquired to feed into a suitable control system for stabilizing the vibration states indirectly. Then, an intelligent optimal control system is proposed to control the motor-mechanism coupling system for periodic motion. In the intelligent optimal control system a fuzzy neural network controller is used to learn a nonlinear function in the optimal control law, and a robust controller is designed to compensate the approximation error. Moreover, a simple adaptive algorithm is proposed to adjust the uncertain bound in the robust controller avoiding the chattering phenomena. The control laws of the intelligent optimal control system are derived in the sense of optimal control technique and Lyapunov stability analysis, so that system-tracking stability can be guaranteed in the closed-loop system. In addition, numerical simulation and experimental results are given to verify the effectiveness of the proposed control scheme.     

Tailoring Pressure Sensitive Adhesives with H6XDI-PEG Diacrylate for Strong Adhesive Strength and Rapid Strain Recovery

The development of flexible electronic technology has led to convenient devices, including foldable displays, wearable, e-skin, and medical devices, increasing the need for flexible adhesives that can quickly recover their shape while connecting the components of the device. Conventional pressure sensitive adhesives (PSAs) can improve recoverability via crosslinking, but often have poor adhesive strength. In this study, new types of urethane-based crosslinkers are synthesized using m-xylylene diisocyanate (XDI) or 1,3-bis(isocyanatomethyl)cyclohexane (H₆XDI) as a hard segment, and poly(ethylene glycol) (PEG) group as a soft segment. The PSA with the synthesized H₆XDI-PEG diacrylate (HPD) demonstrates a significantly improved recoverability compared to XDI-PEG diacrylate and a conventional crosslinker 1,6-hexanediol diacrylate (HDDA) while maintaining high adhesion strength (≈25.5 N 25 mm⁻¹). The excellent recovery property of the PSA crosslinked with HPD is further confirmed by 100k folding tests and 10k multi-directional stretching tests exhibiting high folding and stretching stability. PSA with HPD also shows high optical transmittance (> 90%) even after 20% straining, suggesting its applicability in fields that simultaneously require high flexibility, recoverability, and optical clarity such as foldable displays.     

Active vibration control of a flexible one-link manipulator using a multivariable predictive controller

This article presents a new application of model-based predictive controller (MPC) for vibration suppression of a flexible one-link manipulator using piezoceramic actuators. Simulation and experimental studies were conducted to investigate the applicability of the MPC strategy to control vibration of the flexible structure having multiple inputs and multiple outputs (MIMO). The performance of the proposed technique was assessed in terms of level of vibration reduction. The results demonstrated that the proposed predictive control strategy is well suited for multivariable control of vibration suppression on flexible structures.     

Sol—Gel法制备Li2B4O7薄膜

用Ｓｏｌ－Ｇｅｌ法在以单晶Ｓｉ（１１１）为基底材料上制备出了Ｌｉ２Ｂ４Ｏ７薄膜，对其工艺过程进行了研究，讨论了主要控制参数的作用。     

Integration of VLSI circuits and mechanics for vibration control of flexible structures

The approach to modeling and control of smart flexible structures presented in this paper is based on the concept that an intelligent structure requires an internal knowledge of self to act intelligently. This knowledge can be acquired from local analog models of substructure dynamics and can be used in model-based controller designs. The key to this approach is the synergistic integration of analog VLSI circuit models and control with the sensing and actuation which are then to be embedded into the mechanical structure. This paper presents the motivation, development, and test results of analog VLSI circuit models for use in model-based control of smart flexible structures. Furthermore, control applications for these VLSI circuits are developed and simulation results are presented in which the VLSI circuits are used in adaptive vibration control of a simple mass-spring system.     

应用相敏光放大器抑制光孤子互作用的研究

通过计算机系统仿真研究了应用相敏光放大器(PSA)作为在线放大器抑制光孤子传输系统中孤子间的互作用，并与相应的掺铒光纤放大器(EDFA)光孤子系统进行比较。仿真中考虑了平均孤子和动态孤子两种传输方案。结果表明，应用相敏光放大器代替掺铒光纤放大器作为在线放大器能有效地抑制孤子系统中脉冲的展宽和孤子间的互作用。对于平均孤子，在没有附加其他孤子控制措施的情况下，相敏光放大器系统中孤子间互作用得到有效的抑制，孤子对稳定传输距离得到极大的延长。对动态孤子，相敏光放大器亦表现出良好的抑制孤子间互作用的效果，但孤子脉冲的幅度经长距离传输后显著下降。     

压电主动构件在桁架结构振动控制中的应用

压电主动构件是一种集作动和传感于一体的能承载的器件。文章主要针对研制的压电主动构件,通过实验研究其在桁架结构振动控制中的应用。结果表明,这种压电主动构件作为桁架结构的内控制源,可以有效地提高结构的模态阻尼、抑制结构振动。     

Fast and robust control of systems with multiple flexible modes

This paper derives shaped time-optimal servomechanism (STOS) closed-loop control laws using a phase-plane approach to address flexible structures having multiple flexible modes. The STOS control laws for systems having two and three flexible modes are detailed. The flexible modes are addressed by using multimode input shapers to shape the time-optimal control for the rigid body portion of the system. The altered rigid body phase-plane trajectories resulting from this shaping are solved and used to determine an STOS closed-loop controller. Both "convolution" and "simultaneous" method multimode input shapers are considered. We also improve the robustness to modeling errors of the STOS control. The more robust zero vibration and derivative (ZVD) shaper is used. The ZVD shaper consists of more impulses and has a longer time duration than the simpler zero vibration (ZV) shaper which leads to the more robust STOS (RSTOS) control derived from the ZVD shaper having more switches and longer time response than the STOS control derived from the ZV shaper. Simulation results show that using the ZVD shaper in deriving the RSTOS control improves the robustness to modeling errors in frequency and damping of the flexible mode.     

基于主动约束阻尼层的次镜支撑结构设计

为了提高空间望远镜次镜支撑结构的动力学性能,利用主动约束阻尼层对次镜支撑结构进行了设计,主动约束阻尼层在柔性结构表面覆盖阻尼材料和压电陶瓷材料,是对柔性结构进行振动抑制的有效手段。首先建立了主动约束阻尼层的有限元模型,采用比例微分控制算法对压电陶瓷进行闭环控制,分析了阻尼材料厚度和控制增益对支撑结构阻尼特性的影响,结果表明增大阻尼层厚度或增大控制增益能够提高结构阻尼特性,但增大阻尼层厚度同时也会降低压电陶瓷的驱动性能。对空间望远镜整体结构的分析结果显示,覆盖主动约束阻尼层后支撑结构的固有频率会略微降低,但是次镜位置的频率响应明显下降,次镜的面型精度也有提高。     

A three-axis vibration isolation system using modified zero-power controller with parallel mechanism technique

This paper proposes a module-type three-degree-of-freedom vibration isolation system using modified zero-power control. Three vibration isolation modules are connected together using parallel mechanism to control 3-DOF motions. Each module consists of a common base, an individual middle mass and a common isolation table. The base to the middle mass is suspended by positive springs generated by active and passive system, and the middle mass and the isolation table is connected by negative spring realized by active-type modified zero-power control. The developed system could realize zero-compliance to direct disturbances as well as good ground vibration isolation. Furthermore, the isolation table is supported by a weight support mechanism for supporting heavy payloads. In the previous research, a concentrated middle mass with redundant actuators, in the vertical and horizontal directions, were used. Therefore, a vibration isolation system is proposed in this work using modular concept to overcome those drawbacks. Each module is controlled separately by decentralized control technique, and three modules can be used for three-degree-of-freedom of motion control. Therefore, no redundancy of actuator is occurred. Moreover, an improved zero-power controller is presented that can adjust negative stiffness instead of conventional zero-power controller. The results obtained from analytical and experimental studies show that the modular technique is reliable and efficient approach to vibration control, and represents a suitable alternative to the conventional active vibration isolation systems.     

The Transmission Performance of Non-zero Dispersion Shifted Fiber Communication Systems Using In-line Phase-sensitive Amplifiers

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