混合型加减速前瞻规划的多节NURBS曲线插补策略

Strategy of Hybrid Acc/Dec Look-ahead Planning Interpolation for Multi-block NURBS Curves

为满足复杂型面零件的高速高精加工要求,将造型功能强大的NURBS曲线插补方法作为指定加工曲线的路径给定。为解决伺服系统中指令的不连续及起始速度(或加速度)超越伺服电机的极限,导致实际机械系统无法跟上所给命令的问题,采用了混合多节NURBS曲线前加减速前瞻运动规划。该方法在汲取了传统方法与直接卷积方法两者优点的同时,有效地规避了传统方法中无法降低转角误差和直接卷积方法中加工时间过长的缺点。仿真结果表明,所提出的策略能够使整个插补过程具有高度的柔性和连续性,进而能够满足高速高精加工的要求。

NURBS curve interpolator was proposed as specified demand path for complex profile parts in high speed and high accuracy machining. In order to solve the instruction uncontinuity in the servo system and the starting speed （or acceleration） beyond the servo motor＇s limit, resulting in mechanical system cannot keep up with the given command, the hybrid multi-blocks NURBS curve look-ahead approach before acc/dec was adopted. The proposed approach combined the advantages of conventional approach and direct digital convolution and effectively avoided the unachievable reduction on corner errors in conventional method and the long machining time cost on the direct convolution method simultaneously. The simulation results show that the proposed strategy can make the whole interpolation process more flexible and continuous, and it can satisfy the requirements of high speed and high precision simultaneously.