一种优化轨迹段间衔接速度的自适应前瞻控制

An Adaptive Look-ahead Control Algorithm Using Optimized Transition Velocity between Two Trajectory Segments

为实现数控系统中轨迹段的高速高精加工,提出一种优化轨迹段间衔接速度的自适应前瞻控制算法。在传统轨迹段间速度衔接模型的基础上,该前瞻算法增加了非对称S曲线加减速控制的轨迹长度约束,并根据相邻两段轨迹的长度变化,自适应规划出轨迹段间的最优衔接速度。通过自主开发的x-y数控系统平台进行验证,综合加工性能试验的加工精度可以达到?0.6 mm,加工效率提高9.8%。结果表明所提出的自适应前瞻算法可避免回溯计算转接点速度时计算量显著增加这一问题,并在加工过程中减少大量微小轨迹段的进给轴频繁启停,从而使相邻轨迹段间衔接速度平滑性、加工效率和加工精度方面相对于传统前瞻算法都有明显提高。

To realize a high-speed and a high-precision machining in the CNC system, an adaptive look-ahead control algorithm is proposed, which optimizes the transition velocity between trajectory segments. This algorithm adds the asymmetric S-curve acceleration and deceleration control as the path length constraint, which is based on the traditional velocity transition modes between trajectory segments. And it can adaptively make a plan for the optimal velocity between trajectory segments according to the changes of adjacent trajectory two segments length. An x-y CNC system rig of independent development is used to verify this algorithm. Experimental results show that the machining precision of the comprehensive processing can reach ＆#177;0.6 millimeter and its productivity is enhanced by 9.8%. It indicates that the proposed algorithm can avoid the problem of significant increase calculation when control system back to calculate the transition velocity. It also can reduce frequently start and stop of feed shaft during the process of a large number of tiny trajectory segments. Compared with the traditional look-ahead algorithm, the proposed algorithm can significantly improve the smoothness of transition velocity between the adjacent trajectory segments, the machining efficiency and precision.