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1.
Taking into account the effect of structural compliance, inverse dynamics of the active over-constrained parallel manipulator 6PUS–UPU with five degrees of freedom is solved in this article. Firstly, the relationship between driving forces and actuated force screws of each limb is derived. Then the coordination of elastic deformation between limbs which consider the effect of gravity and inertia is acquired. Finally the unique solution of driving forces for the active over-constrained parallel manipulator is derived by incorporating the force equilibrium equation of the moving platform. To validate the theoretical derivation, dynamics simulation model of manipulator based on rigid–flexible mixed structure is shown and numerical examples are given. Comparison with the traditional method of dynamics based on pseudo-inverse is also made. Finally, a feasible experimental method, as an effective test to the theoretical calculation, is proposed and applied on the prototype.  相似文献   
2.
This paper is concerned with the coordinative control problem of networked nonlinear multi-agents (NNM) with communication delays. A high-order fully actuated (HOFA) model is introduced to describe the nonlinear multi-agents. Based on this model, a HOFA predictive coordination method is proposed to compensate for the communication delays actively and achieve simultaneous stability and consensus. This method largely simplifies the design of networked nonlinear multi-agents and makes the control performance be same for networked nonlinear multi-agents with and without communication delays. The analysis on the closed-loop systems derives the simultaneous stability and consensus criteria of networked nonlinear multi-agents using the HOFA predictive coordination method. With the presented way of designing HOFA predictive coordination controllers, a simulated example demonstrates the advantages of the proposed method.   相似文献   
3.
【】结合闸门控制设计经验,针对液压式闸门,对不同型式闸门开度测量方法进行了比较,重点介绍了用恒力收带式传感器测量液压式闸门开度的方法,并通过应用案例说明了该方法的有效性和实用性,期望能为今后设计选型提供参考。  相似文献   
4.
Al/KClO_4点火器的输出性能是火工分离装置总体设计的关键参数。为了更准确地描述Al/KClO_4点火器的输出性能,通过修正经典内弹道方程组假设,引入火药力修正系数,建立了改进Al/KClO_4内弹道分析模型。编写Matlab数值求解算法,计算了密闭爆发器内Al/KClO_4点火器压力峰值、压力上升时间和单位面积冲量等参数,结合实验分析了这些参数随药量和空腔容积的变化规律,计算结果与实验结果吻合较好。研究表明,Al/KClO_4点火器产生的压力峰值随药量的增加而增大,随空腔容积的增加而减小,在小容腔(5 m L)范围内,空腔容积增加1倍,压力峰值下降约40%.  相似文献   
5.
介绍了煤气化装置水煤浆气动控制球阀的研究过程,分析了煤气化工况系统的主要技术难点,给出了产品国产化研究的具体解决方案,并对产品结构的设计计算提出了新的思路。  相似文献   
6.
7.
飞翼型飞机主起落架与舱门联动收放机构设计   总被引:1,自引:0,他引:1  
对飞翼型飞机的起落架与舱门联动收放提出了新的设计思想.通过对空间进行分析、布局,应用CATIA进行了运动仿真分析.并对联动收放机构的强度和刚度进行了分析计算.在满足要求的基础上,实现了狭小空间内起落架与舱门的联动收放.  相似文献   
8.
振动台是一种对高层建筑、大型桥梁和基础设施等大型结构进行抗震性能试验的重要设备。为了提高振动台有效载荷,以便进行大尺寸或全尺寸结构试验,振动台通常采用液压驱动冗余并联机构。本文首先根据液压驱动冗余振动台机液作用机理,建立了冗余振动台的整体机液动力学模型,并提出一种适用于液压驱动冗余振动台的自由度控制结构。之后,针对冗余驱动内力耦合问题,采用基于雅克比矩阵伪逆的内力协调控制方法,协调控制各激振器间的出力,减少各个激振器间的内力耦合。最后,通过仿真分析,验证了本文提出的自由度控制和内力协调控制的有效性。  相似文献   
9.
While strategies employing early or late direct-injection of fuel can improve emissions, they also can lead to impingement of liquid-phase fuel on the piston and/or cylinder wall due to low in-cylinder temperatures and densities during the injection event. Previous work has shown that liquid-phase fuel films formed in this way can lead to pronounced degradations in efficiency and emissions. To avoid these problems, a quantitative understanding of fuel-property effects on the liquid penetration length is needed, and this understanding must include conditions where in-cylinder thermodynamic conditions and the injection rate vary with time. This work reports liquid penetration lengths measured in an optical engine under such time-varying conditions. Diagnostics included laser light scattering for measurement of the liquid length and conventional pressure-data acquisition for heat-release analysis. Unsteady liquid penetration was characterized for different injection timings, injection pressures, intake-manifold pressures, and fuel volatilities to gain an understanding of the relative importance of these factors. Fuel volatility was studied by using two fuels, 2,2,4,4,6,8,8-heptamethylnonane (HMN) and 2,2,4-trimethylpentane (TMP), which have very different volatility characteristics. Measured liquid lengths changed as in-cylinder conditions changed, with increasing temperature and density during the compression stroke causing a decrease in liquid length, and decreasing temperature and density during the expansion stroke causing an increase in liquid length. Intake-manifold pressure and fuel volatility were found to be primary factors governing liquid length. Heat loss from the charge gas to the engine and local charge cooling due to fuel vaporization were found to have a secondary influence on liquid length. Injection pressure was found to have little effect.  相似文献   
10.
以固定协调控制下绿信比确定方法及感应控制原理为基础,设计了基于逻辑规则的感应式协调控制下绿信比优化流程,提出了感应协调控制下绿灯时间实时优化方法,确定了最大弹性绿灯时间计算方法。算例表明,该方法具有较好的实用性。  相似文献   
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