复杂约束下的五轴数控系统自适应速度规划

Adaptive Velocity Planning under Complex Constraints for 5-axis CNC Systems

为充分发挥五轴机床的运动性能,提升机床的加工效率,提出一种复杂约束下的自适应速度规划方法。以弓高误差、刀具的进给运动和驱动轴的运动性能为约束,建立基于时间最优的五轴机床速度规划模型;在位移-速度坐标系中,采用二阶B样条对速度曲线进行描述,有效降低了优化变量的维度,提高了速度曲线的求解效率;采用具有连续一阶导数的罚函数对模型去约束化,并以BFGS算法为基础设计了具有鲁棒性的速度曲线求解策略。仿真表明,所提出的算法可适用于形状复杂的加工路径,算法计算高效,规划得到的速度曲线能满足各项约束并提高加工效率。采用S形试件进行实际加工测试,进一步验证了算法的有效性。

To maximize the property of five-axis CNC machine tool and improve it efficiency without impairment of precision, an adaptive velocity planning algorithm under complex constraints is proposed. Taken confined chord error, tangential movement of cutter and driving performance of axis into consideration, a time-optimal velocity planning model is established;expressing velocity profile with second-order B-spline in the displacement-velocity coordinate system to reduce the dimension of the optimization variables and improve efficiency of the model solving;A penalty function with continuous first-derivative is conducted to remove constraints of the model;a robust solution strategy for solving the model is designed based on BFGS algorithm. As shown in simulation, the proposed algorithm is advanced in dealing with complex tool paths efficiently. velocity profiles derive from the algorithm satisfy various of constraints well and increase processing efficiency markedly. The practice machining of S-shaped specimen further validates effectiveness of the algorithm.