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引入新支链的冗余驱动方法是目前减少或消除并联机构奇异的有效方法,如何确定所引入支链的结构形式、布置方式和最少支链个数是该冗余驱动方法的核心问题,然而关于这些问题至今尚没有系统的理论和方法。依据螺旋理论系统分析并联机构的约束奇异、驱动奇异和支链奇异三种奇异位形,强调位于工作空间内部的约束奇异和驱动奇异位形是对机构性能影响最为严重的位形,提出一种基于非瞬时支链位形设计的并联机构内部奇异消除方法,以3-RPR型、3-RRR型、4-RPTR型、3-RRRT型和3-RPS型等五种典型的并联机构为例,系统阐述该方法的设计过程。结果表明除了动平台和基平面重合的位形以外,该方法能够消除并联机构的其所有内部奇异位形。该成果为解决冗余驱动方法的关键理论问题提供了参考。 相似文献
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平面三自由度冗余并联机构的驱动奇异性分析 总被引:5,自引:1,他引:5
分析了PRPR-2PRR、PRR-2PRR和4-PRR等三种平面冗余并联机构的驱动奇异位形,通过与平面3-PRR非冗余并联机构的比较,研究了采用不同机构冗余类型消除并联机构奇异位形的方法及其特点,为冗余并联机构的尺度综合、路径规划和控制提供了依据。 相似文献
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《机械科学与技术》2017,(7):998-1004
在Delta机构的基础上提出一种含冗余驱动的三平移并联机构。基于螺旋理论计算了该并联机构的自由度,分析了位置反解,推导出雅可比矩阵,结合Gosselin奇异分析法,对Delta机构的奇异位形进行分析并找出两种新的奇异位形。将Delta机构和冗余驱动并联机构的奇异性进行比较,为了验证理论分析结果,引入可操作度这一运动性能指标,基于数值法对两种机构的奇异性进行比较。理论分析结果表明冗余驱动并联机构可以实现和Delta机构相同的功能,但其第二类奇异位形明显比Delta机构少;数值分析结果表明选取合适的工作空间和机构参数可减少并联机构的奇异位形,同时也验证了理论分析结果的正确性。 相似文献
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提出利用变分的方法对闭环机构的奇异位形进行分类与判定,并揭示相应奇异位形的不同物理意义。变分方法适用于一般闭环机构的奇异位形分析。 相似文献
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奇异位形是并联机构的固有性质,机器人应该避免在奇异位形附近区域工作。提出一种Tri-cept机器人奇异位形分布的可视化方法。该方法首先分析Tricept机器人雅可比矩阵的构成,结果表明,解析雅可比矩阵行列式为零时,机构处于奇异位形,然后根据可视化途径将Tricept奇异位形的空间分布情况绘制出来。 相似文献
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Although it is common to eliminate the singularity of parallel mechanism by adding the branched chain with actuation redundancy, there is no theory and method for the configuration synthesis of the branched chain with actuation redundancy in parallel mechanism. Branched chains with actuation redundancy are synthesized for eliminating interior singularity of 3-translational and 1- rotational(3T1R) parallel mechanisms. Guided by the discriminance method of hybrid screw group according to Grassmann line geometry, all the possibilities are listed for the occurrence of interior singularities in 3T1R parallel mechanism. Based on the linear relevance of screw system and the principles of eliminating parallel mechanism singularity with actuation redundancy, different types of branched chains with actuation redundancy are synthesized systematically to indicate the layout and the number of the branched chainsinterior with actuation redundancy. A general method is proposed for the configuration synthesis of the branched chains with actuation redundancy of the redundant parallel mechanism, and it builds a solid foundation for the subsequent performance optimization of the redundant actuation parallel mechanism. 相似文献
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An extremely reliable remote control system for subsea blowout preventer stack is developed based on the off-the-shelf triple modular redundancy system. To meet a high reliability requirement, various redundancy techniques such as controller redundancy, bus redundancy and network redundancy are used to design the system hardware architecture. The control logic, human-machine interface graphical design and redundant databases are developed by using the off-the-shelf software. A series of experiments were performed in laboratory to test the subsea blowout preventer stack control system. The results showed that the tested subsea blowout preventer functions could be executed successfully. For the faults of programmable logic controllers, discrete input groups and analog input groups, the control system could give correct alarms in the human-machine interface. 相似文献
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Kenneth Anderson 《ISA transactions》1991,30(4):107-116
Although most control project specifications for modern digital systems include references to redundancy and fault tolerance, little effort usually is expended to analyze the cost additions to the project. Risk assessment applied to a control system most often maximizes reliability without regard to cost, though the additional expense may have no significant justification. On some projects, redundancy is carried to extremes, while other times partial redundancy is added with minimal gain in overall system reliability.
This paper will assist the project engineer in properly analyzing the benefits of redundancy versus the true cost of this capability and the effect this will have on a project. The methodology described attempts to achieve the system's objectives and quantity the requirements that will be placed on system reliability. The emphasis is not on the cost or safety benefits to the process but on the relative cost/benefits associated with different offerings that implement fault tolerant or redundant functions. 相似文献
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In this paper the effect of kinematic redundancy in order to reduce the singularity loci of the direct kinematics and to increase the operational, i.e., singularity-free, workspace is demonstrated. The proposed approach consists of additional prismatic actuators allowing one or more base joints to move linearly. As a result, a selective reconfiguration can be performed in order to avoid singular configurations. Exemplarily, kinematically redundant schemes of four structures, the 3RRR, the 3RPR, the 6UPS, and the 6RUS, are considered. The relationship between the redundancy and the operational workspace is studied and several analysis examples demonstrate the effectiveness of the proposed concept. Furthermore, the additional benefit of an increasing number of redundant actuators is discussed. 相似文献
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故障诊断中多传感器信息冗余性的研究 总被引:5,自引:0,他引:5
从信息论的观点出发,导出了传感器信息融合中的宙余性和互补性的定量描述,分析了传感器冗余性和互补性的特点,并从实际应用出发提出了信息冗余性的质量指标--相关熵的概念,用它来间接评价传感器信息间的冗余性取得了较好的效果。这为设备运行故障诊断技术的深入研究打下了基础,具有工程应用价值。 相似文献
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冗余设计技术与可靠性关系研究 总被引:10,自引:1,他引:10
冗余设计技术是提高产品可靠性水平的有效设计技术之一。但是在什么情况下采用冗余设计,在哪个设计层面采用冗余设计,从目前的所有资料中,未见有明确地分析与探讨。本文做出了冗余设计应从最基层单元做起的论断,并给出了详细的数学证明。 相似文献
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由于火炮控制系统中对交流伺服系统的高可靠性要求,提出了双CPU的冗余控制方案。基于TI公司的一款浮点型DSP,采用两片TMS320F28335为主芯片的硬件冗余方案,运用解析冗余的双CPU故障检测法判别故障并进行故障定位,实现冗余热切换,从而保证了系统工作的连续性。 相似文献