基于高精度轮廓误差估计的交叉耦合控制  

Cross-coupled Controller Based on High-precision Contouring Error Estimation

作　　者：赵欢[1] 朱利民[1] 丁汉[1] 

机构地区：[1]上海交通大学机械系统与振动国家重点实验室,上海200240

出　　处：《机械工程学报》2014年第3期158-164,共7页Journal of Mechanical Engineering

基　　金：国家高技术研究发展计划(863计划;2012AA041309);国家重点基础研究发展计划(973计划;2011CB706804)资助项目

摘　　要：在交叉耦合控制中,轮廓误差估计公式不仅用于估计轮廓误差大小,而且用于确定交叉耦合系数。估计公式的准确性直接影响轮廓控制精度,传统公式在大曲率位置存在明显估计误差。针对平面自由曲线的轮廓误差估计,研究点-曲线距离函数的微分特性,利用距离函数的Taylor展开提出高精度二阶估计方法,并指出基于密切圆近似的传统二阶方法在象限切换时存在的计算问题,同时对传统公式进行修正。在此基础上设计综合位置闭环反馈和交叉耦合控制器的轮廓跟踪控制器,并结合NURBS曲线进行两轴控制试验。试验结果表明:所提出的二阶方法相比于传统公式轮廓误差估计精度更高;基于所提出的二阶方法和传统公式设计的交叉耦合控制器,前者相比于后者可以显著提高轮廓控制精度。In the contour-following task, the contouring error estimation is not only used to estimate the errors, but also to yield the cross-coupled gains. Thus, it directly determines the accuracy of the contouring control. However, the traditional estimation methods may cause significant error when the curvature is large. For the planar arbitrary curves, the differential properties of the point-to-curve distance function are investigated, and a second-order estimation method based on its Taylor＇s expansion for evaluating contouring errors is developed. The calculation problem for the traditional second-order estimation methods encountered in the case of quadrant converter is presented, and the corresponding computational formulas are corrected. Based on the developed quadratic contouring error estimation method, a contouring controller, which combines the position feedback and the cross-coupled controllers, is developed. A NURBS curve is applied for biaxial experimental validations. The results indicate that： The proposed estimation method has higher accuracy than the traditional ones; the designed cross-coupled controller based on the proposed estimation method improves the contouring accuracy significantly compared with those based on the traditional estimation methods.

关 键 词：轮廓控制 轮廓误差 交叉耦合控制 距离函数 

分 类 号：TP273[自动化与计算机技术—检测技术与自动化装置]