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1.
针对汽车理论中尚无整车质量分配系数研究的缺憾,考虑垂向和侧向路面激励的复合影响,以14个自由度整车传统物理模型为背景,对簧载质量进行空间动力学分析,借助4个轮系方位与簧载质量质心处的运动学关系,研究车体垂直、侧向、俯仰角、侧倾角和横摆角这五种运动,进而推导得到整车悬架与4个1/4悬架系统间的动力耦合定量关系,发展与完善汽车质量分配系数理论,并为今后汽车悬架系统振动控制、转向与操纵系统平稳性的研究提供新的视角与思路。 相似文献
2.
In this paper, the effects of second-order difference-frequency wave forces on the global motion of an offshore wind turbine system with a large displacement under the survival condition are studied. In this case, the hydrodynamic force is the main force because the blades are feathered to reduce the lifting force. The first-order hydrodynamic forces are calculated by WADAM, while the second-order wave forces are calculated by a customized MATLAB module. Then the hydrodynamic coefficients are transferred to the wind turbine analytical code FAST. Through the comparisons of dynamic responses between the first- and second-order numerical models, it is found that the second-order wave forces significantly influence the motion of floating wind turbine under the survival condition. Moreover, neglecting the second-order force significantly underestimates the tension forces in the mooring lines. 相似文献
3.
船舶在海上航行时,不可避免会受到海风、海浪、海流的环境干扰,会产生艏摇、横摇等现象,影响船舶的适应性,产生诸多不利影响。针对船舶的横摇减摇控制系统的数学模型,在考虑系统的非线性和参数不确定性的情况下,利用李雅普诺夫稳定性理论推导使系统渐近稳定的充分条件,设计鲁棒控制器,用MATLAB软件进行求解和仿真,验证方法的可行性。 相似文献
4.
甘乃峰 《鞍山师范学院学报》2015,(6):1-6
研究了套代数框架下具有内部环结构控制器的线性系统鲁棒镇定问题。首先,介绍了一种新型的控制器———具有内部环结构控制器以及它的等价形式———典范或对偶典范控制器;其次,给出了系统具有扰动情况下鲁棒镇定的几个充分条件;最后,得出相应的结论。 相似文献
5.
为了对变桨距控制器及其执行机构进行研发和测试,提出一种数字物理混合的综合实验平台解决方案.将风电场风况、风力机、发电机等外部环境采用数字模型仿真,变桨距控制器及执行机构采用物理真机运行,结合计算机辅助设计技术,完成软硬件间的数据采集与转换,实现嵌入式变桨距控制器综合实验平台的数字物理混合设计.仿真结果表明,该平台可靠性高,稳定性好,成本低,能够解决变桨距控制器的实验室开发与研究. 相似文献
6.
Numerical simulation and experimental tests were carried out to examine the hydrodynamic behaviors of a double-column floating system of gravity cage under wave conditions. A floating system of gravity cage can be treated as a small-sized floating structure when compared with the wavelengths. The main problem in calculating the wave loads on the small-sized floating structure is to obtain the reasonable force coefficients, which may differ from a submerged structure. In this paper, the floating system of gravity cage is simplified to a 2D problem, where the floating system is set symmetrically under wave conditions. The motion equations were deduced under wave conditions and a specific method was proposed to resolve the problem of wave forces acting on a small-sized floating system of gravity cage at water surface. Results of the numerical method were compared with those from model tests and the hydrodynamic coefficients Cn and Cr were studied. It is found that Cn ranges from 0.6 to 1.0 while Cr is between 0.4 and 0.6 in this study. The results are useful for research on the hydrodynamic behavior of the deep-water gravity sea cages. 相似文献
7.
研究了Lorenz系统的混沌控制问题,利用线性反馈控制方法设计了一种基于状态变量的线性反馈控制器,通过变量x,y的相互作用实现了不稳定平衡点的稳定控制,并用李雅普诺夫方法证明了在混沌控制器作用下,控制系统的稳定性.数值仿真结果验证了混沌控制器的有效性和鲁棒性. 相似文献
8.
A great deal of stabilization criteria has been obtained from study of stabilizing interconnected systems. The results obtained are usually based on continuous systems by state feedback. In this paper, decentralized impulsive control is presented to stabilize a class of uncertain interconnected systems based on Lyapunov theory. The system under consideration involves parameter uncertainties and unknown nonlinear interactions among subsystems. Some new criteria of stabilization under impulsive control are established. Two numerical examples are offered to prove the effectiveness and practicality of the proposed method. 相似文献
9.
INTRODUCTIONWiththedevelopmentofscienceandtech-nology,thestructuresofcontrolsystemsaregettingmoreandmorecomplicated.Thiskindofsystemhasthecharacteristicoflargedimension,andin-terconnectionamongsubsystems.Generally,thiskindofsystemiscalledinterconnectedlargesystem.Thestudyofinterconnectedsystemsismotivatedbyquiteanumberofpracticalapplicationsrangingfrompowernetworks,transportation,aerospace,economics,management,andsoon.Thestrategiestocontrolinterconnectedsystemsaredividedintotwokinds:centr… 相似文献
10.
Wang Liedong 《大连大学学报》1993,(1)
本文以四边形 Mindlin 板元作 Hourglass 控制的稳定性方法,可有效地消除不适的运动模式和不产生自锁。本文将控制 Hourglass 模式的稳定矩阵方法应用到三维非线性动力响应问题中,算例表明动力响应解的 Hourglass 模式振荡得到了明显改善.但这个解还不令人十分满意,尚未彻底控制 Hourglass 模式振荡,还有待进一步研究. 相似文献
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12.
Nomenclaturex,y,x ·, y·-displacement and velocity of rotor-x,-y,x-·,-y·-displacement and velocity of rotor , di mension less¨x,¨y-acceleration of rotor¨-x,¨-y-acceleration of rotor ,di mensionlessω-rotating speed of rotor-ω-rotating speed of rotor ,di mensionlessx,y,z-Cartesian coordinates-x,-y,-z-Cartesian coordinates ,di mensionless2m-mass of rotorg-acceleration of gravityG-weight of rotor ,di mensionlesse=e2x e2y-mass eccentricity of rotorex,ey-mass eccentricity of rotor in thexan… 相似文献
13.
提出一种稳健性极点配置自适应控制算法，该算法由精选一优化ＩＶ参数估计器和稳健性极点配置控制器构成．算法的稳健特性在于当系统存在未建模动力学及不可测量有界噪声时，被控对象的输出能被镇定． 相似文献
14.
To improve the processing efficiency and the quality of orbital milling hole of aerospace Al-alloy, the big-pitch influence on cutting force and hole quality was studied experimentally. First, a program based on horizontal lathe was proposed based on kinematics analysis of orbital milling. Then, the cutting force at different stages and the hole quality with different pitches were measured. Results show that the axial force and radial force increase with the pitch amplification during orbital milling. However, the axial force in the orbital milling hole is about 8—10 times smaller than that in the conventional drilling. The diameter error of milling hole is 48—93 μm, and the surface roughness of milling hole is 1.2—1.7 μm. Finally, an orbital milling device with big pitch was designed. 相似文献
15.
根据电烤炉炉温的控制特点,针对温控系统的大纯滞后性,采用了带Sm ith预估器的数字PID控制器设计方案,对控制算法和控制软件进行了设计.并应用仿真技术,选择适当的调节参数,使系统达到了满意的控制效果. 相似文献
16.
Calculation method of ship collision force on bridge using artificial neural network 总被引：1，自引：0，他引：1
Ship collision on bridge is a dynamic process featured by high nonlinearity and instantaneity. Calculating ship-bridge collision force typically involves either the use of design-specification-stipulated equivalent static load, or the use of finite element method （FEM） which is more time-consuming and requires supercomputing resources. In this paper, we proposed an alternative approach that combines FEM with artificial neural network （ANN）. The radial basis function neural network （RBFNN） employed for calculating the impact force in consideration of ship-bridge collision mechanics. With ship velocity and mass as the input vectors and ship collision force as the output vector, the neural networks for different network parameters are trained by the learning samples obtained from finite element simulation results. The error analyses of the learning and testing samples show that the proposed RBFNN is accurate enough to calculate ship-bridge collision force. The input-output relationship obtained by the RBFNN is essentially consistent with the typical empirical formulae. Finally, a special toolbox is developed for calculation effi- ciency in application using MATLAB software. 相似文献
17.
The technique of non-stationary oll film force database for hydrodynamic bearing is introduced and its potential applications in nonlinear rotor-dynamics are demonstrated.Through simulations of the locus of the shaft center aided by the database technique,nonlinear stability analysis can be performed and the natural frequency can be obtained as well.The easiness of “assembling” the individual bush forces from the database to form the bearing force.makes it very convenient to evaluate the stability of various types of journal bearings,Examples are demonstrated to show how the database technique makes it possible to get technically abundant simulation results at the expense of very short calculation time. 相似文献
18.
A model-based estimator design and implementation is described in this paper to undertake combined estimation of vehicle states
and tire-road friction coefficients. The estimator is designed based on a vehicle model with three degrees of freedom (3-DOF)
and the dual extended Kalman filter (DEKF) technique is employed. Effectiveness of the estimation is examined and validated
by comparing the outputs of the estimator with the responses of the vehicle model in CarSim in three typical road adhesion
conditions (high-friction, low-friction, and joint-friction roads). Simulation results demonstrate that the DEKF estimator
algorithm designed is able to obtain vehicle states (e.g., yaw rate and roll angle) as well as road friction coefficients
with reasonable accuracy. 相似文献
19.
The focus of this article is on scale score transformations that can be used to stabilize conditional standard errors of measurement (CSEMs). Three transformations for stabilizing the estimated CSEMs are reviewed, including the traditional arcsine transformation, a recently developed general variance stabilization transformation, and a new method proposed in this article involving cubic transformations. Two examples are provided and the three scale score transformations are compared in terms of how well they stabilize CSEMs estimated from compound binomial and item response theory (IRT) models. Advantages of the cubic transformation are demonstrated with respect to CSEM stabilization and other scaling criteria (e.g., scale score distributions that are more symmetric). 相似文献
20.
Collapses of transmission towers were often observed in previous large earthquakes such as the Chi-Chi earthquake in Taiwan
and Wenchuan earthquake in Sichuan, China. These collapses were partially caused by the pulling forces from the transmission
lines generated from out-of-phase responses of the adjacent towers owing to spatially varying earthquake ground motions. In
this paper, a 3D finite element model of the transmission tower-line system is established considering the geometric nonlinearity
of transmission lines. The nonlinear responses of the structural system at a canyon site are analyzed subjected to spatially
varying ground motions. The spatial variations of ground motion associated with the wave passage, coherency loss, and local
site effects are given. The spatially varying ground motions are simulated stochastically based on an empirical coherency
loss function and a filtered Tajimi-Kanai power spectral density function. The site effect is considered by a transfer function
derived from 1D wave propagation theory. Compared with structural responses calculated using the uniform ground motion and
delayed excitations, numerical results indicate that seismic responses of transmission towers and power lines are amplified
when considering spatially varying ground motions including site effects. Each factor of ground motion spatial variations
has a significant effect on the seismic response of the structure, especially for the local site effect. Therefore, neglecting
the earthquake ground motion spatial variations may lead to a substantial underestimation of the response of transmission
tower-line system during strong earthquakes. Each effect of ground motion spatial variations should be incorporated in seismic
analysis of the structural system. 相似文献