整体叶盘高效强力复合铣A轴高精度控制技术研究

A轴单元作为五轴数控机床的关键功能部件,其控制精度直接影响整体叶盘的加工精度和表面质量.针对摩擦、齿隙、参数摄动和测量噪声等非线性干扰对A轴伺服系统控制精度的影响,提出了基于线性二次型最优控制(LQC)和滑模控制(SMC)相结合的鲁棒控制算法(LQSMC).该方法以系统状态空间表达式及LQC为基础,通过引入基于卡尔曼滤波器和控制输入的状态估计,对系统状态空间模型进行改进并定义新的滑模面方程,使得改进后的控制算法在性能上接近LQC并能有效抑制SMC的抖振.仿真分析和实验结果表明,LQSMC算法具有控制精度高、鲁棒性强和抑制干扰能力强等优点,其能有效提高A轴伺服系统的定位精度和跟踪精度,使整体叶盘型面加工精度和表面一致性得到保证,并显著降低了表面粗糙度.

Technology Research on High-precision Control of A-axis in Efficient and Powerful Milling Machine for Blisk Manufacturing

The control precision of the A-axis as a key functional component of a five-axis CNC machine tool directly affects the machining accuracy and surface quality of the blisks to be manufactured on it. Taking into consideration the influences of friction, backlash, parameter perturbation, measurement noise and other nonlinear disturbances on the control precision of an A-axis servo system, a robust control algorithm (LQSMC) based on the integration of linear quadratic optimal control (LQC) and sliding mode control (SMC) is proposed. Based on the system state space expression and LQC, this method improves the system state space model and defines a new sliding mode surface equation by introducing a state estimation based on the Kalman filter and the control input, and the improved control algorithm not only approaches the performance of LQC but also inhibits the chattering of SMC. Simulation analysis and experimental results show that LQSMC possesses high control precision, strong robustness, strong interference suppression ability and other advantages. It can effectively improve the positioning and tracking precision of the A-axis servo system, ensure blade machining precision and surface consistency, and significantly reduce surface roughness.