共查询到20条相似文献，搜索用时 46 毫秒
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徐明利 《湖州师范学院学报》2011,33(1)
从NURBS曲线构造原理出发,给出了一般的参数曲线插补基本实现过程.对于参数曲线插补所固有的速度波动广问题,从算法仿真和实验加工两个方面给出了验证.采用常见的CAM软件ProE辅助设计软件,验证了该技术方案的可行性. 相似文献
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李红 《西安铁路职业技术学院学报》2008,(3)
所谓插补就是“数据密化”的过程。在对数控系统输入编程轨迹的特征点坐标后，数控系统根据这些信息运用一定算法，实时地计算出各个中间点的坐标，从而对各坐标轴进行脉冲分配，完成曲线加工。插补不仅应保证精度要求，更应算法简单，满足控制的实时性要求。本文针对非参形式二维曲线及参数形式任意空间曲线，提出了一种基于反馈校正思路的插补算法。 相似文献
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参数曲线的通用插补算法研究 总被引：1，自引：0，他引：1
传统的数控系统能够直接进行插补的曲线一般只有直线和圆弧两种,对于复杂曲线的加工,目前尚无一种通用的高精度算法。本文对参数曲线的插补算法进行研究,提出一种通用的变步长试探修正插补算法,为平面和空间的参数曲线提供了一个统一的插补计算方法。 相似文献
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本文主要对基于B样条类曲线的直接插补算法的曲线段间过渡问题进行了研究和阐述。B样条曲线是有多段曲线拟合而成的,插补计算时段间的平滑过渡是十分重要的,尤其是当采用预估校正的方法来确定参数时更需要注意段间的过渡情况。本文首先叙述了预估校正确定参数的方法,接着着重讨论了基于B样条类曲线插补计算时的段间过渡问题。最后用程序实现了插补算法,并给出了程序的测试结果。 相似文献
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数控车床加工对象是回转面,对于规则曲线所组成的圆柱面、圆锥面、圆弧面、球面等的加工,只要使用普通程序利用直线插补或圆弧插补指令即可完成。但当出现非圆曲线（椭圆、抛物线、双曲线）构成的回转体时,手工常规编程无能为力,采用软件自动编程又受设备和条件的限制时．则可以采用宏程序来编制。 相似文献
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基于逐点比较法的计算原理,改进了插补算法的数学模型,对插补算法进行了优化。经实验证明,改进后的逐点比较法在加工零件时,插补精度有所提高,速度加快,可以获得较高的经济效益。 相似文献
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现代运动控制系统一般都通过插补算法实现各种直线、曲线的运动。插补算法的目的就是为了实现被控对象以给定的速度沿着制定的路线运动。文章先提出了逐点比较法,然后建立了基本的直线插补,引入了速度控制算法,并比较了两种算法的优劣。 相似文献
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Wilfrid Bilodeau 《Interchange》1993,24(3):241-270
Résumé Cet essai évoque les contextes pédagogiques de l'écriture au-delà des formes d'écriture convenues en recherche, et questionne les usages scolaires de l'écriture. J'y suggère d'autres usages inspirés d'une approche qui inverse les rapports usuels entre communication et représentation, entre kinésis et mimésis. Cette approche vise une démystification du pouvoir de l'écriture à représenter le réel, à dominer la communication, et une promotion d'une écriture expressive et métaphorique, favorisant l'appropriation de cette technologie virtuellement libérante.Université Laval 相似文献
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Mother's Day--母亲节 Mother's Day falls on the second Sunday in May every year. This is the occasion we show appreciation to our mothers and to people who have worked so hard to take care of us. Today, I'm sharing thoughts from a friend about mother, love,and the study of English. When we were young students, a teacher touched our heart,and we all miss her very much on this special day in May. 相似文献
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Kate Lorenz 《海外英语》2007,(12):40-41
Whether your preferred destination is the executive suite or simply the nearest exit from your current position, don't let your job take you aimlessly down any path. In fact when it comes to career planning, don't think in terms of "jobs" at all, says corporate transitions expert William Bridges, Ph.D. Instead he suggests building your career plan on "doing the work you're best at for the employers who need it." 相似文献
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正Cognitive developmental theories deal with the processes ofthinking progress,including memory,attention,problem solvingand decision-making,from childhood through adolescence to adult-hood.In this essay I will compare and contrast the developmentaltheories of Piaget and Vygotsky,both of which play an importantroleintheresearchofcognitive development.Piaget's developmental theory is a cognitive developmentaltheory which is mainly about the nature and development of human 相似文献
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《今日中学生》2014,(Z2)
正Clever Bobby Brown was very proud of his young son.Once he was talking to a visitor,telling the man how clever his son was."The boy is only two years old,"he said,"and he knows all animals.He's going to be a great naturalist(生物学家).Here,let me show you."He took a book of natural history from the bookself,placed Bobby 相似文献
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正A We find many kinds of animals on the earth.Some animals,like tigers,and elephants,live in big forests.They are called wild(野生的)animals.Some others,like cows and dogs,live with man and we call them domestic(驯养的)animals.Animals are important to man.Man catches wild animals for fur(毛皮)and meat.Domestic animals give man food,too.They are more important than wild animals.Without them life would be hard. 相似文献
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正It was a beautiful spring morning.There wasn't a cloud in the sky,and the sun was warm but not too hot,so Mr Green was surprised when he saw an old man at the bus stop with a big,strong black umbrella in his hand.Mr Green said to him,"Are you going to have rain today,do you think?""No,"said the old man,"I don't think so."Then are you carrying the umbrella to keep the sun off 相似文献
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《今日中学生》2014,(17)
正AA philosopher(哲学家)who went to call on a sick friend was told at thedoor:"He is alreadydeparted(过世).""Well,tell him I called,"replied the philosopher.BSocrates(苏格拉底)had troubles in his marital(婚姻的)life.Out of ithe gave the youth a piece of advice:"If you get a good wife.you will becomevery happy;if you get a bad one,you will become a philosopher—and thatis good for every man." 相似文献
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