In the prediction of active vibration isolation performance, control force requirements were ignored in previous work. This may limit the realization of theoretically predicted isolation performance if control force of large magnitude cannot be supplied by actuators. The behavior of a feed-forward active isolation system subjected to actuator output constraints is investigated. Distributed parameter models are developed to analyze the system response, and to produce a transfer matrix for the design of an integrated passive-active isolation system. Cost functions comprising a combination of the vibration transmission energy and the sum of the squared control forces are proposed. The example system considered is a rigid body connected to a simply supported plate via two passive-active isolation mounts. Vertical and transverse forces as well as a rotational moment are applied at the rigid body, and resonances excited in elastic mounts and the supporting plate are analyzed. The overall isolation performance is evaluated by numerical simulation. The simulation results are then compared with those obtained using unconstrained control strategies. In addition, the effects of waves in elastic mounts are analyzed. It is shown that the control strategies which rely on unconstrained actuator outputs may give substantial power transmission reductions over a wide frequency range, but also require large control force amplitudes to control excited vibration modes of the system. Expected power transmission reductions for modified control strategies that incorporate constrained actuator outputs are considerably less than typical reductions with unconstrained actuator outputs. In the frequency range in which rigid body modes are present, the control strategies can only achieve 5–10 dB power transmission reduction, when control forces are constrained to be the same order of the magnitude as the primary vertical force. The resonances of the elastic mounts result in a notable increase of power transmission in high frequency range and cannot be attenuated by active control. The investigation provides a guideline for design and evaluation of active vibration isolation systems.

The trend of high speed and light weight of the modern machines brings about some tremendously serious vibration and noise,so vibration isolation and noise reduction of flexible systems in high frequency range is a very important issue that must be considered in mechanical designs.The flexibility of vibrating systems being sufficiently taken into account,a generalized dynamics model and its mathematical description of fully flexible isolation systems with flexible machine and flexible base(FMFB),which are subjected to multi-excitations and supported by multi-mounts,is presented,by the sub-structural mobility synthesis and the transfer matrix approach.This model not only can readily degenerate to rigid machine and rigid base(RMRB),rigid machine and flexible base(RMFB),and flexible machine and rigid base(FMRB) isolation systems,etc.,but also it can be used to analyze the passive and active isolation.In accordance with the combination of subsystems,the formulation of transmissibility and power flow of different systems is performed.The couple and transmission characteristics of various isolation systems are investigated,and some valuable results are obtained to give some important guidance for isolation designs.

For estimating the vibration transmission accurately and performing vibration control efficiently in isolation systems, a novel general model is presented to predict the power flow transmitted into the complicate flexible bases of laminated beams. In the model, the laminated beam bases are simulated by the first-order shear deformation laminated plate theory, which is relatively simple and economic but accurate in predicting the vibration solutions of flexible isolation systems with laminated beam bases in comparison with classical laminated beam theories and higher order theories. On the basis of the presented model, substructure technique and variational principle are employed to obtain the governing equation of the isolation system and the power flow solution. Then, the vibration characteristics of the flexible isolation systems with laminated bases are investigated. Several numerical examples are given to show the validity and efficiency of the presented model. It is concluded that the presented model is the extension of the classical one and it can obtain more accurate power flow solutions.

To estimate the power flow transmission from the vibrating internal combustion engines to the complex elastic foundation accurately, a general analytical model is presented by extending the classical one. In the proposed model, the Mindlin plate, instead of the classical thin plate based on Kirchihnff's hypothesis, is used to model the elastic isolation foundations. Substructure technique and variational principle are employed to derive the governing equation and solve the power flow transmitted into the thick or orthotropic beam foundations with different configurations. Comparative study on the transmission characteristics of the power flow of the general isolation systems with the classical cases is conducted. Numerical simulation shows that the presented model is valid and it can obtain more accurate power flow solutions than the classical one.

Mobility is an important concept for vibration isolation and vibration response characteristics of a structure can be represented essentially by its point mobility on its surface. The analytical expressions of the driving point mobility of a finite long and thin cylindrical shell subjected to combination of multiple excitations are derived based on classical equations of vibration. The potential mechanism governing vibration response of shells is investigated. The results show that coupled mobilities may play an important role in energy input of structure vibration. The formulae of mobilities proposed can be used directly for study on passive and active vibration isolation of supports of thin cylindrical shells.

建立了机器-基础耦合振动状态空间方程，对系统的耦合振动特性与模型降阶进行了研究．给出了状态观测器构造的一般方法，从功率流传递的角度，对模态耦合振动线性二次调节器（LQR）控制效果进行了评估，数值计算表明：机器-基础的耦合振动主要表现为机器Z向模态与基础第一阶弯曲模态的耦合振动．以模态速度为LQR控制指标可有效地衰减共振频率处功率流传递、阶跃响应收敛时间较短．图5表1参7

In aircraft and submarine engineering, a vibrating motor is usually mounted on a flexible foundation. The dynamic coupled characteristic of the motor-foundation is studied in the state space. The model simplification and modal displacement measurement methods are presented. The power flow transmission from the motor to the foundation is then controlled by a linear quadratic regular (LQR). The numerical calculation results show that the power flow transmission is mostly attributed by the motor rigidbody mode and the first bend mode of the foundation. In the low frequency band, the dynamic behavior of the coupled system could be described by a eight order state equation. The power flow transmission in the resonance bands could be reduced effectively with modal velocity being objective index of LQR.

The equipment vibration and noise,which is caused by a machine on the flexible foundation in engineering,is studied on dynamic model of multiple mountings isolation system.The dynamic transfer equations are deduced,which are composed of the machine,isolators and elastic foundation.From the point of view of energy transmission,the aim is to discover influence of different parameter of set,isolators stiffness and foundation stiffness so that reference is provided for industrial design parameters.

The stiffness matrix of a rigid instrument and a flexible foundation dynamic coupled system was derived in vibration mode space. The natural frequencies distribution of the coupled system was studied numerically. The numerical results show that the first frequency of the coupled system is commonly lower than the instrument's mounting frequency. In the low frequency band, the instrument's bounce mode is coupled with the flexible foundation's first bending mode distinctly. In the high frequency band, the flexible foundation's mode is the dominant mode of the coupled system. The model studied in this paper can be considered as an on-board precision instrument vibration isolation model.

Based on mobility matrices of subsystem, the dynamics characteristic of the flexible multidimensional isolation system is investigated; the control effects of different strategies are studied by using the power flow as the appraised target. The studies show that the active control strategies worked in the frequencies domain after the rigid body modes in the multidimensional flexible system, in all strategies put forward in this paper, the total power flow minimum is much more effective, it can decrease the amount and the value of the resonance; the axial power flow minimum nearly have no control effect.

以特性传递矩阵描述复杂机械系统中子结构输入、输出力与速度矢量关系,提出了复杂振源激励、多弹性支承与基础板结构三维耦合隔振系统传递矩阵力学模型.考虑隔振支承多维波动效应,推证了弹性支承耦合振动传递矩阵,为复杂系统功率流特性及隔振器多维驻波效应研究确立了有效途经.数值模拟计算表明,基础板结构的前两阶弯曲共振模态是高频域系统功率流提高的主要原因.振源力矩或垂向激振力诱发的隔振器纵向谐振使系统功率流明显提高;增大基础板厚度,驻波共振峰值提高.

A novel analytical active–passive model of floating rafts, a type of special isolation structures which present high-level vibration isolation and are widely used in large ships and submarines particularly, is developed for the first time. Then the mobility matrices of the subsystems are derived, thereby a general mathematical description of this combined active–passive model is realized. Based on the model, the concepts and relationships of machine control, raft control and full control are extensively discussed. The solution of the power flow transmitted into the foundation is obtained, and power transmission characteristics of the system are investigated under different control types when minimization of total power flow strategy is applied. Through numerical simulations, the control efficiencies of the different control types (machine control, raft control and full control) are compared, illustrating the efficiency of the presented model, obtaining some valuable results, and presenting some general design principles of the active floating raft isolation systems.

By applying mobility and modal approach to a familiar vibration isolat ion model of machine in the engineering, the expression of the power flow input into basic beam is obtained. And the equivalent damp of super-elastic effect o f TiNi Shape Memory Alloy is calculated by simulating its cycle curve using experimen t data. According to super-elastic effect of TiNi shape memory alloy, the allo y threads are applied in the model as a kind of equivalent damp material. Differe nt figures are drawn by the simulation in case of SMA thread as damp material as well as using generic damp material equivalent to the damp of SMA thread under diffrent frequencies. From the figu res, the eff ect of vibration isolation is analyzed in case of SMA thread as damp materia l and the superiority of SMA thread as damp material is revealed.

In this paper from the beginning of a kind of familiar vibration isolation model of mechine in the engineering,we work out the expression of the power flow.And we calculate equivalent damp of super-elastic effect of TiNi Shape Memory Alloy through simulating its cycle curve.According to super-elastic effect of TiNi shape memory alloy,we apply the alloy threads to the model as a kind of equivalent damp material.And we analyze the effect of vibration isolation while applying SMA thread as damp material.under different temperature and displacement.

To solve vibration isolation of diesel engines installed on the flexible decks of ships or vessels, the sub-system mobility technique was employed to establish an active-passive combined control model of the floating raft system, and general mathematic description of active-passive control of the floating raft isolation system was given based on mobility matrixes. The concepts of machine control, raft control and full control of floating raft systems etc. were presented, and the inter-relations were discussed. Considering the power flow transmitted into the foundation as the cost function, the power transmission characteristics of active floating raft system were investigated and compared under the different control methods when minimized power flow strategy and minimized axial force strategy were applied respectively, and the general active isolation designing principles of floating raft systems were presented.

The limitation of one-stage isolation system at high frequencies makes people study more complicated structure to improve the isolation effect. Insert ing the medium mass between the vibration source and the base is an effective wa y, which can be easily applied in engineering. The mechanism of power flow tr ansmissi on in this structure is studied by presenting the theoretical model, deriving th e exp ressions of the power flow spectra and plotting its curve. The studies show that the isolation effect at high frequencies can be improved by inserting the inter mediate mass. The system should adopt symmetrical structure from the viewpoint o f vibration control. Furthermore, the medium mass and the base's stiffness can affect the positions of their resonance respectively, which can be used to acqui re wide isolation frequencies range.

采用一种结合Hopfield网络模型的遗传算法,解决了自动化立体仓库中固定货架拣选作业路径优化问题。 在利用Hopfield/Tank神经网络的快速局部搜索能力的同时,又利用了遗传算法的全局寻优特性,有效地获得全 局优化的拣选路径。仿真结果表明,算法能够满足待拣选货位点数目在较大范围内变动的要求。

针对工程中常见的复杂柔性耦合隔振系统,本文对隔振器斜置的情况进行了研究.在充分考虑基础结构的柔性、各支承间的耦合作用的前提下,分析了机器设备-隔振器-柔性基础这一振动隔离系统的动态特性,推导了系统功率流传递表达式,并且结合工程实际对斜置隔振系统的理论模型进行了具体的数值计算,绘制了功率流传递曲线,着重分析了隔振器倾斜角度的变化对输入到基础梁功率流的影响.

A theoretical model of two-dimensional active control for ambulance stretcher suspension is proposed. The shaping filter equations of time domain are developed to provide optimal estimates of the disturbance dynamics. Numerical calculations are carried out to examine the effectiveness of proposed control scheme. It shows that the optimal control with disturbance feed-forwarded provides significant reduction of vertical and pitch vibration transmission compared with the passive stretcher suspension. The relative displacement and resonance peak values of vibration components in the sensitive frequency range of human body are effectively suppressed in comparison with that of the 1-DOF active control stretcher.