基于阻尼力调节的城轨车辆复合结构车身减振控制系统设计

为了降低车身振动给城轨车辆复合结构产生的危害,利用阻尼力调节技术优化设计城轨车辆复合结构车身减振控制系统。在考虑城轨车辆复合组成结构和工作方式的情况下,构建城轨车辆复合结构模型。在该模型下,结合城轨车辆的运行环境,模拟城轨车身在不同场景下的振动过程。利用安装的车身运行传感器,获取城轨车辆的实时运行数据,提取城轨车身振动特征,计算车身阻尼力调节量的理论值。采用可调阻尼器作为执行元件,执行可调阻尼力调节任务,在系统减振控制器的支持下,实现城轨车辆复合结构车身减振控制功能。通过系统测试得出结论：应用基于阻尼力调节的城轨车辆复合结构车身减振控制系统后,车身振动频率和振动幅值得到明显降低。     

上海A型地铁车辆弹性车体与转向架耦合振动分析

基于上海A型地铁车辆弹性车体有限元模型,建立弹性车体的刚柔耦合动力学模型,用其研究车体垂向弹性对运行平稳性的影响,分析弹性车体与转向架的耦合振动,探究车体弹性共振的机理.结果表明,在车体刚度低的情况下,该型地铁车辆车体弹性对车辆运行平稳性影响较大;车体的弹性共振并非由车体与转向架耦合振动引起,在车辆悬挂及车体的设计过程中应当考虑几何滤波现象引发车体弹性共振对车辆平稳性的影响。     

基于模糊神经网络的二自由度主动悬架滑模控制系统设计

主动悬架滑模控制系统受到行驶路面影响,车体震动加速度功率谱密度与实际密度不一致,导致系统控制效果不佳,提出基于模糊神经网络的二自由度主动悬架滑模控制系统设计;基于二自由度硬件结构,在主动悬架液压伺服系统中安装蓄能器,减小空间内存;采用磁流变阻尼器,调整电流大小控制阻尼;设计自适应减振座椅悬架并计算阻尼值,实现了主动悬架的控制;考虑路面不规则度,构建二自由度主动悬架滑模控制模型,依据牛顿定律计算悬架弹性元件受力;采用模糊控制规则校正控制误差,采用模糊神经网络设计主动悬架滑膜控制方案,经迭代处理得到满足优化要求的解,实现滑膜控制;由试验结果可知,车体震动加速度功率谱密度与实际密度一致,从最初的0 ms^(-2)到最终的1.5 ms^(-2),具有良好控制效果,确保乘车的舒适性。     

基于遥测技术的新型传感器柔性结构振动优化控制方法

为了提高新型传感器柔性结构振动抑制能力,提出基于遥测技术的新型传感器柔性结构振动优化控制方法。在速度坐标系、体坐标系下构建新型传感器柔性结构的振动动力学模型,采用卡尔曼滤波方法实现对新型传感器柔性结构振动参数的融合调节和小扰动抑制。采用气弹模态参数识别方法,进行新型传感器柔性结构的振动模态参数识别,提取新型传感器柔性结构振动特征量,采用遥测技术进行新型传感器柔性结构振动惯性参数识别,结合状态反馈调节方法进行稳定性控制,实现新型传感器柔性结构振动优化控制。仿真结果表明,采用该方法进行新型传感器柔性结构振动优化控制的自适应性较好,具有很好的振动抑制和控制能力。     

Active vibration control of large space flexible slewing truss using cable actuator with input saturation

This paper proposes a composite approach to implementing attitude tracking and active vibration control of a large space flexible truss system. The system dynamic model is based on Hamilton's principle and discretized using the finite difference method. A nonlinear attitude controller for position tracking is developed based on the input‐output linearization of the discretized system, which can effectively improve system performance compared with a traditional proportional‐differential feedback controller. A taut cable actuator scheme is presented to suppress tip vibration because the mechanical model is a large large‐span spatial structure; furthermore, because the cable has the feature of unilateral input saturation constraint, which can provide only a pulling force, a nonlinear quadratic regulator controller is developed by introducing a piecewise nonquadratic cost function to suppress the vibration of the flexible structure. To investigate the factors that influence the damping effects of the cable, the parametrically excited instability of a cable under 2 supports is analyzed. Simulation results illustrate that the proposed attitude controller can implement the task of position tracking, and the vibration suppression control law is shown to be optimal for functional performance with input saturation.     

Designing feedforward command shapers with multi-objective genetic optimisation for vibration control of a single-link flexible manipulator

This paper presents investigations into the design of a command-shaping technique using multi-objective genetic optimisation process for vibration control of a single-link flexible manipulator. Conventional design of a command shaper requires a priori knowledge of natural frequencies and associated damping ratios of the system, which may not be available for complex flexible systems. Moreover, command shaping in principle causes delay in system's response while it reduces system vibration and in this manner the amount of vibration reduction and the rise time conflict one another. Furthermore, system performance objectives, such as, reduced overshoot, rise time, settling time, and end-point vibration are found in conflict with one another due to the construction and mode of operation of a flexible manipulator. Conventional methods can hardly provide a solution, for a designer-oriented formulation, satisfying several objectives and associated goals as demanded by a practical application due to the competing nature of those objectives. In such cases, multi-objective optimisation can provide a wide range of solutions, which trade-off these conflicting objectives so as to satisfy associated goals. A multi-modal command shaper consists of impulses of different amplitudes at different time locations, which are convolved with one another and then with the desired reference and then used as reference (for closed loop) or applied to system (for open loop) with the view to reduce vibration of the system, mainly at dominant modes. Multi-objective optimisation technique is used to determine a set of solutions for the amplitudes and corresponding time locations of impulses of a multi-modal command shaper. The effectiveness of the proposed technique is assessed both in the time domain and the frequency domain. Moreover, a comparative assessment of the performance of the technique with the system response with unshaped bang–bang input is presented.     

On topology optimization of damping layer in shell structures under harmonic excitations

This paper investigates the optimal distribution of damping material in vibrating structures subject to harmonic excitations by using topology optimization method. Therein, the design objective is to minimize the structural vibration level at specified positions by distributing a given amount of damping material. An artificial damping material model that has a similar form as in the SIMP approach is suggested and the relative densities of the damping material are taken as design variables. The vibration equation of the structure has a non-proportional damping matrix. A system reduction procedure is first performed by using the eigenmodes of the undamped system. The complex mode superposition method in the state space, which can deal with the non-proportional damping, is then employed to calculate the steady-state response of the vibrating structure. In this context, an adjoint variable scheme for the response sensitivity analysis is developed. Numerical examples are presented for illustrating validity and efficiency of this approach. Impacts of the excitation frequency as well as the damping coefficients on topology optimization results are also discussed.     

挠性飞行器时间燃料优化姿态机动控制的振动抑制

研究了使用反作用推力作为执行机械的姿态控制系统,针对挠性飞行器姿态机动控制,给出了命令整形时间燃料优化设计方法,在机动过程中,挠性振动对机动时间、燃料消耗和机动精度具有很大的影响,文中给出了挠性振动抑制手段,使机动完成的同时,振动得到有效抑制,由于振动频率和振动阻尼不易精确参数化,所以考虑挠性振动掏设计方法对振动频率和振动阻尼的鲁棒性设计问题,最后通过仿真验证了方法的可行性和有效性。     

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     

FLEXIBLE SPACECRAFT VIBRATION SUPPRESSION USING PWPF MODULATED INPUT COMPONENT COMMAND AND SLIDING MODE CONTROL

This paper presents a dual‐stage control system design method for the rotational maneuver and vibration stabilization of a spacecraft with flexible appendages. In this design approach, attitude control system and vibration suppression were designed separately using lower order model. The design of attitude controller was based on sliding mode control (SMC) theory leading to a discontinuous control law. This controller accomplishes asymptotic attitude maneuvering in the closed‐loop system and is insensitive to the interaction of elastic modes and uncertainty in the system. The shaped command input controller based on component synthesis vibration suppression (CSVS) method is designed for reduction of flexible mode vibration, which only requires information about natural frequency and damping of the closed system. Additionally, to extend the CSVS method to the system with on‐off actuators, pulse‐width pulse‐frequency (PWPF) modulation is employed to control the thruster firing and integrated with the CSVS method. Simulation results have been proven the potential of this technique to control flexible spacecraft.     

Predictive end-point trajectory control of elastic manipulators

This article presents an approach to end-point trajectory control of elastic manipulators based on the nonlinear predictive control theory. Although this approach is applicable to manipulators of general configuration, only planar flexible multi-link manipulators are considered. A predictive control law is derived by minimizing a quadratic function of the trajectory error of the end-points of each link, elastic modes, and control torques. This approach avoids the instability of the zero dynamics encountered in the controller design using feedback linearization and variable structure control techniques for end-point control. Furthermore, the derived predictive controller is robust to uncertainty in the system parameters. Simulation results are presented for a one-link flexible manipulator to show that in the closed-loop system accurate end-point trajectory control and vibration damping can be accomplished. © 1996 John Wiley & Sons, Inc.     

Decentralized sliding mode control for flexible link robots

A technique using augmented sliding mode control for robust, real-time control of flexible multiple link robots is presented. For the purpose of controller design, the n-link, n-joint robot is subdivided into n single joint, single link subsystems. A sliding surface for each subsystem is specified so as to be globally, asymptotically stable. Each sliding surface contains rigid-body angular velocity, angular displacement and flexible body generalized velocities. The flexible body generalized accelerations are treated as disturbances during the controller design. This has the advantage of not requiring explicit equations for the flexible body motion. The result is n single input, single output controllers acting at the n joints of the robot, controlling rigid body angular displacement and providing damping for flexible body modes. Furthermore, the n controllers can be operated in parallel so that compute speed is independent of the number of links, affording real-time, robust, control.     

Robust passivity-based control design for active nonlinear suspension system

In this article, we propose a novel interconnection and damping assignment passivity-based control (IDA-PBC) design for a quarter car nonlinear active suspension system. As an energy shaping method, IDA-PBC is suitable for applying the main concept of skyhook (SH) control. In addition to the damping term, we utilize the characteristics of the energy shaping method to change the sprung and unsprung masses, thereby strengthening the vibration suppression effect. An IDA-PBC-based controller design for an active suspension system, which includes a nonlinear spring, a nonlinear damper, and mass uncertainty, is proposed. Different from most IDA-PBC applications, which tend to control the position or the velocity, our methods focus on transforming a nonlinear suspension system into a desired linear system with ideal aseismatic properties. Unlike a conventional controller using the SH control strategy, we design a virtual vehicle body and an unsprung mass in addition to the damper coefficients. By deriving the port-Hamiltonian form of the suspension system from its dynamics and rewriting it based on the relative coordinates, we obtain a feedback law that only uses the relative displacement and velocity of the suspension system. We derive the conditions for ensuring the global asymptotical stability of the suspension system and propose the guidelines for parameter selection that can guarantee robust stability against parameter uncertainties.     

高耸柔性结构振动模态阻尼比参数识别仿真

针对当前结构振动模态阻尼比参数识别相关方法存在识别率低等问题,结合柔性结构振动形态复杂度高等特点,提出基于ERA的高耸柔性结构振动模态阻尼比参数识别方法。通过标定相机的内外参数,使用两个相机同时对柔性结构的动态进行拍摄生成结构测点图像,采用三维动态重构方法对高耸柔性结构振动情况进行预处理,利用Harris角点检测法确定振动位移,并采集位移数据,得到模态阻尼比参数集合。基于数据采集结果,通过ERA方法对高耸柔性结构振动模态阻尼比参数进行识别。实验结果表明,上述方法具有较强的识别性能、柔性结构振动形态简单的特点。     

Modal disparity enhancement through optimal insertion of nonstructural masses

Stiffness variation can be generated in a structure by the systematic application and removal of tension in cables connecting points in the structure. This strategy has been shown to result in modal disparity, a property of the combined structure and cable system that allows vibration energy to flow from one set of modes to another. This facilitates the design of simplified strategies for modal control of flexible structures using only a few selected modes. For some structures, however, cable tension switching may not result in sufficient modal disparity, and, in such cases, the rate of energy transfer across modes may not be sufficient to ensure rapid vibration suppression. Here, it is shown that such difficulty can be alleviated by the insertion of a few nonstructural masses. A procedure is outlined for determining the optimal location of these masses. Simulation results are presented to illustrate vibration control in a 3-D frame.     

An enhanced anti-disturbance attitude control law for flexible spacecrafts subject to multiple disturbances

As well-known disturbance rejection methods, active disturbance rejection control and disturbance observer-based control can effectively improve the control performances of complex systems in the presence of disturbances. However, the accurate rejection of multiple disturbances for control systems of practical engineering, for example, the attitude control system of flexible spacecraft, is still a bottleneck problem. In order to further improve the anti-disturbance capability and reduce the conservativeness, this paper proposes a novel enhanced anti-disturbance control law for the attitude control system of flexible spacecraft by combining active disturbance rejection control and disturbance observer-based control in a unified framework. More specifically, the disturbance from flexible vibration is described by an uncertain exogenous system based on the partially known information including elastic damping ratios and modal frequencies. The disturbance observer-based control is utilized to estimate and thereby reject this disturbance. On the other hand, the other disturbances such as external environmental disturbance and complex model nonlinearity are merged into a equivalent disturbance with bounded derivative, which is compensated by using the active disturbance rejection control law. Stability and robustness analysis are carried out for the disturbance observer and extended state observer. Finally, simulation results of low-earth-orbit flexible satellite are presented to verify the effectiveness of proposed methods.     

Computer-aided design integration of a reinforced vibration isolator for electronic equipment’s system basedon experimental investigation

Electronic equipment’s system is always manufactured as a superprecision system. However, it will be used in harsh environment. For example, the computer in moving vehicles will be acted by vibrations. The objective of this paper is to provide a systematic investigation to test and computer-aided design of the vibration isolator for protection of electronic equipment’s system in harsh vibration environment. A micro-oil damping vibration isolator is designed and manufactured through coupling the oil and spring by ingenious tactics. The structure of the oil damping vibration isolator can achieve circulating oil damping function with an inner tube and an outer tube (some orifices are manufactured on upside and underside of the inner tube). The dynamics of the key model machine is systematically investigated. Based on the test, a nonlinear dynamic model for the vibration isolator is presented by analyzing the internal fluid dynamic phenomenon with respect to the vibration isolator. The model considers all the physical parameters of the structure. Comparisons with experimental data confirm the validity of the model. In the other, the model is integrated by introducing normalization measure. The normalization model shows the actual physical characteristics of the oil damping vibration isolator by considering quadratic damping, viscous damping, Coulomb damping, and nonlinear spring forces. An approximate solution is deduced by introducing harmonic transform method and Fourier transform method. Therefore, a parameter-matching optimal model for computer-aided design of the vibration isolator is build based on approximate solution. An example confirms the validity of the computer-aided design integration.

粘弹性阻尼材料在柔性机械手振动控制中应用的实验研究

本文对一实验用柔性机械手进行了粘弹性约束阻尼处理,以减少柔性振动,改善控制系统的稳定性,提高定位精度.文中给出了测量机械手柔性振动的实验方法,对约束阻尼处理前和处理后的机械手进行了柔性振动、残余振动、重复定位精度等实验研究,并做了比较.     

柔怀臂的主极点设置控制

柔性臂控制是一个活跃的研究课题,已经有不少结果,最多用的方法是通过模态分析以控制柔性臂低价振型（一般为首一或二个振型）本文提出了一种“主极点”（ＤｏｍｉｎａｎｔＰｏｌｅｓ）控制器,它可以控制任何数目的低价振型而不失稳定性,该控制器可以方便地转变自适应控制器以应会中模态频率与阻尼系数与实际柔性臂之间的误差,本文用李雅普诺夫理论证明本控制系统的全局稳定性（Ｇｌｏｂａｌｓｔａｂｉｌｉｔｙ）。     

基于车体横移振动的高速列车虚拟复合阻尼天棚控制算法研究

高速列车车体横向随机振动由车体的横移振动、侧滚振动和摇头振动三自由度合成,是影响车体横向运行平稳性的关键;为了改善列车横向运行平稳性,提高半主动控制性能;通过建立某型高速列车动力学模型,对车体横向振动特性进行分析,得出横移振动的加剧是造成车体合成横向振动和横向平稳性恶化的主要原因;通过分析在传统天棚阻尼控制算法下分别以车体合成横向振动为反馈和以横移振动为反馈对车体横向振动的控制效果,得出采用以车体横移振动为反馈的传统天棚阻尼控制算法对车体横向振动的抑制效果更佳;在此基础上,提出一种以车体横移振动为反馈的虚拟复合阻尼天棚控制算法,并进行联合仿真分析;结果表明:相比于被动控制,采用虚拟复合阻尼天棚控制算法后,车体合成横向振动加速度峰值、均方根值和平稳性改善率分别达到了46%、43%和19.5%,均高于采用传统天棚阻尼控制算法;可见,采用虚拟复合阻尼天棚控制算法在抑制车体合成横向振动,改善车体横向平稳性方面控制性能更佳。