基于NURBS的航空发动机叶片焊接修复的轨迹规划

Trajectory planning of welded repair for aero-engine blades based on NURBS curve

由于航空发动机叶片截面形状复杂,焊接修复精度高,采用基于非均匀有理B样条曲线(non-uniform rational B-spline,NURBS)方法进行轨迹规划.利用NURBS曲线分别表示叶片截面的前缘、尾缘、叶盆和叶背等四部分曲线,经过升阶整合处理,获得统一表达式,从而进行基于NURBS的曲线插补.综合弓高误差、法向加速度和编程进给速度对焊接速度和精度的影响,实现了进给速度的自适应控制.提出了一种分段前瞻控制,简化了前瞻算法,提高了前瞻效率.最后通过仿真试验验证该算法的可行性和焊接精度.结果表明,该算法是可行的,具有良好的焊接精度.

As the complex shape of blades and the high requirement for welding repair of blades,NURBS(non-uniform rational B-spline) is adopted for trajectory planning.The section curves of blades is composed of leading edge,trailing edge,basin side and vacuum side.In order to get an unified expression and simplify the interpolation process,the order of the expression of leading edge and trailing edge must be increased.Then curve interpolation is carried out based on NURBS.Based on chord error,normal acceleration and programmed feed rate,adaptive control of the feed rale is achieved.This paper proposes a segmented look-ahead algorithm to improve the efficiency.Finally,a simulation is given to verify the feasibility and accuracy of this algorithm.