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在分析传统PID控制策略的基础上,提出了兆瓦级变速变桨型风电机组减载控制策略,考虑变增益和加滤波器控制,并基于风电机组专用软件BLADED的外接口,自主研发外部控制器,分析减载控制策略对整机性能、载荷的影响.结果证明,采用这种控制策略能有效地减小风轮上的载荷,使风电机组的运行更加平稳. 相似文献
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有限单元法在计算电机定、转子运动问题的时候,遇到了困难.运动时,定、转子的相对角度不断的改变,对不同转角的转子要进行多步的电磁场计算.而运动会造成气隙单元发生畸变,造成了有限元法求解运动问题时前处理复杂;由于不需要构成单元,无单元法可从根本上消除由转子位置变化引起的网格扭转变形.可将无单元法同有限元法耦合来求解运动问题,在气隙使用无单元法,在其他区域使用有限元网格.采用径向基点插值型无单元法(RPIM)和有限元(FEM)直接耦合方法来解决定、转子之间相对运动问题.计算结果证明,该耦合方法的计算精度满足要求.将其应用在电机电磁场数值计算中,可解决由于有限元法气隙单元畸变产生的误差. 相似文献
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提出虹吸式屋面雨水排除系统的设计理论,理解雨水斗的排水能力与斗前水深的关系,解释虹吸形成的全过程。通过对虹吸式雨水排除系统和重力式雨水排除系统的比较,指出虹吸式雨水排除系统的优越性。随着虹吸式雨水系统应用技术的不断发展和成熟,虹吸式屋面雨水排除系统作为一种新型的雨水排放系统,将逐步被设计人员和工程建设单位认可和接受。 相似文献
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代谢组学是生物机体在病理生理、遗传、环境或行为的不同刺激下,对机体所产生代谢产物变化的研究,是生物领域研究中一种重要的研究手段,已在植物学、营养学、中药学、微生物学、临床疾病诊断等研究领域得到广泛应用。动物应激一直是畜牧行业关注的热点,许多因素可导致动物应激,常见的应激类型有冷应激、热应激、氧化应激、束缚应激、噪音应激、运输应激,还有不可预知的慢性应激等,这些应激均可对动物机体产生一定危害。目前,代谢组学也已应用于动物应激领域的研究,本文对代谢组学在动物的冷应激、热应激、氧化应激及束缚应激研究中的应用作一综述。 相似文献
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In order to solve kinematic redundancy problems of a hydraulic quadruped walking robot, which include leg dragging, sliding, impingement against the ground, an improved gait planning algorithm for this robot is proposed in this paper. First, the foot trajectory is designated as the improved composite cycloid foot trajectory. Second, the landing angle of each leg of the robot is controlled to satisfy friction cone to improve the stability performance of the robot. Then with the controllable landing angle of quadruped robot and a geometry method, the kinematic equation is derived in this paper. Finally, a gait planning method of quadruped robot is proposed, a dynamic co-simulation is done with ADAMS and MATLAB, and practical experiments are conducted. The validity of the proposed algorithm is confirmed through the co-simulation and experimentation. The results show that the robot can avoid sliding, reduce impingement, and trot stably in trot gait. 相似文献
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Most existing legged robots are developed under laboratory environments and,correspondingly,have good performance of locomotion.The robots‘ability of walking on rough terrain is of great importance but is seldom achieved.Being compliant to external unperceived impacts is crucial since it is unavoidable that the slip,modeling errors and imprecise information of terrain will make planned trajectories to be followed with errors and unpredictable contacts.The impedance control gives an inspiration to realize an active compliance which allows the legged robots to follow reference trajectories and overcome external disturbances.In this paper,a novel impedance force/position control scheme is presented,which is based on Cartesian force measurement of leg's end effector for our hydraulic quadruped robot The simulation verifies the efficiency of the impedance model,and the experimental results at the end demonstrate the feasibility of the proposed control scheme. 相似文献