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录 译文： of he is is is by of 1） he is so on to As is As a of of to be to to by up is as to to to on up 2） of by in We in in of to we to is so on of of In D, so on D, D, D, D on We AD in M AD AD/AM I) on C in on of to At to on on C G, on an on in to l to is an (on as of oto do to to to in to of to he by in in as to to on to to a by of 3） of by to be as is as by NC on to On as a in is is it a by of 4） on of so on to to in to is a of in is by of in an to a of a or of is to is C It is to to of C A of of P he is is of is In to of a to on is of in of of NC is is a in of of of it of or is of C It is In of of as as to F of in In of is by on of at at in to as in an as or is or to to is in be in In as at as it a of is on or by of In is of of of or be in C a of to in a a C of or to or a in CU is is a is to be in C. in is to of is to be of or in to a be be to to be to of a of a by of of of of is of a of by is to by in to A of is in be a by of C of a of a in to of as as in be by C A of a of C to a C be by an on or an be or to to so to of or of or to on/of so of of on of to be A is of to as of or a is on it is to be be of be by to do in is is in of of is of of to be in it to C in 950s is in is of to is of a of as of in of of or to is of a C on of of in of of in of be by or of be by a of on a or by an as or 1 on J. 1,999, 18 (1): 14l 144. 2 Du ,M)/AM J. 1998, 28 (5): 5155. 3 , on . to 1,999, 28 (2): 12 文： 数控机床开环控制伺服系统与数控生产设备 摘要 开环系统的优点是系统简单、成本低，但缺点是精度低。反向间隙、丝杠螺距误差、起停误差等都会影响定位精度。下面几种改进措施可以使定位精度明显改善。 关键字：数控系统、开环系统 1） 反向间隙误 差补偿 数控机床加工刀具与工件的相对运动是依靠驱动装置带动齿轮、丝杠转动，从而推动工作台面等移动部件产生位移来实现的。作为传统元件的齿轮、丝杠尽管制造精度很高，但总免不了存在间隙。由于这种间隙存在，当运动的方向改变时，开始段时间必然会引起驱动元件的空走，出现指令脉冲推不动执行元件的局面。这就影响了机床的加工精度，即指令脉冲与实际进给步数不相符合，产生加工误差 因此，开环数控系统一般都设置有反向间隙误差补偿功能，用以补足空走的步数反向间隙差补偿就是首先实测反向进给的误差，把它折算成脉冲当量数，作为间隙补偿子程 序的输出量，当计算机判断出现的指令为反向运动时，随即调用间隙补偿子程序，通过输出补偿脉冲消除反向间隙后再进行正常的插补运行。 2） 常值系统性定位误差补偿 类库以供设计者调用。这样在零件的设计阶段，设计者只需输入特征的参数，系统直接生成特征的实例模型：在数据库中我们必须存储相关的特征类的结构信息，数据库表集就是用于存储这一部分的相关信息。根据特征类型定义的需要，我们定义了特征类编码表、特征类版本信息表表示特征类型；定义了特征类构造表表达特征类的结构；并通过零件特征配置表与零件的特征层信息联系起来。特征层数据 表集是本零件模型数据库设计的核心，记录了特征实例模型的设计、工艺等信息。特征构造表记录了特征的几何结构；特征尺寸表、特征形位公差表、特征表面粗糙度
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