S形加减速的嵌套式前瞻快速算法  

A Fast Nested Look-ahead Algorithm with S-shape Acceleration and Deceleration

作　　者：何均[1] 游有鹏[1] 陈浩[1] 王化明[1] 

机构地区：[1]南京航空航天大学江苏省精密与微细制造技术重点实验室,江苏南京210016

出　　处：《航空学报》2010年第4期842-851,共10页Acta Aeronautica et Astronautica Sinica

基　　金：国家自然科学基金(50605031;50975144);江苏省精密与微细制造技术重点实验室开放基金(Z0610-052-06)

摘　　要：前瞻处理功能是现代数控系统的标志性功能之一,前瞻算法设计直接关系到数控机床的加工效率和运动平稳性。针对目前广泛研究的S形加减速前瞻算法复杂、难以满足实时性要求的问题,从工程实现的角度设计了嵌套式自适应前瞻算法。依据S形加减速曲线的对称性建立了速度规划模型,通过对加速度等效曲线逼近提高了模型求解效率,给出了S形速度规划曲线构造和校验两主要运算阶段的解析解。以连续短直线加工为例,给出了完整的嵌套式快速前瞻算法和实例加工验证。实验结果表明,所提出的算法能获得全局最优运动效率,计算量不足传统方法的30%,结果精确,耗时稳定,能满足现代数控系统甚至是高速高精度数控系统对前瞻处理的实时性要求。给出的解析结果对S形加减速模型的求解有通用意义,可适用于连续短直线、二次曲线以及非均匀有理B样条曲线(NURBS)等参数曲线的S形加减速前瞻速度规划。Look-ahead is one of the most significant functions of modern computer numerical control （CNC） systems and look-ahead algorithms are directly related to the machining efficiency and motion stability of a CNC machine tool. For decades,the look-ahead algorithm based on S-shape acceleration and deceleration （Acc/Dec） has been widely adopted,which however is too complex and time-consuming for real-time requirements. This article proposes a nested adaptive look-ahead algorithm to deal with these weaknesses. Based on the jerk symmetry in S-shape Acc/Dec,a velocity planning model is designed,and an approximation algorithm to the equivalent acceleration profile is proposed to improve model solution efficiency. Analytical solutions are given in the two main stages of velocity curve construction and checking. Taking the machining of continuous micro-segments as an example,the complete fast nested look-ahead algorithm with machining verification is provided. Machining results show that global optimal motion efficiency can be obtained with the proposed algorithm,while computation cost is less than 30% that in the traditional method. This algorithm can meet the real-time requirements to look-ahead in modern CNC systems and even in high-speed high-precision CNC systems. The analytical results given in this article are of general significance for the solution of an S-shape Acc/Dec model,and the algorithm should be applicable to look-ahead planning of continuous micro-segments,conic and even parametric curves such as non-uniform rational B-spline （NURBS）.

关 键 词：前瞻算法 速度控制 加减速控制 柔性加减速 数控系统 

分 类 号：TH164[机械工程—机械制造及自动化] TP273.5[自动化与计算机技术—检测技术与自动化装置]