硬盘两级伺服磁头定位系统的鲁棒控制

Robust control of a dual-stage HDD head positioning servo system

为实现更快捷和精确的硬盘磁头定位,在硬盘固有的音圈电机上附加一个压电微激励器,从而构成了硬盘两级伺服磁头定位系统。在控制系统的设计中,利用了压电微激励器的频率特性来估计其位移输出,进而估计音圈电机的输出位移;对音圈电机的控制设计采用了一种积分增强的鲁棒完美跟踪(RPT)控制技术,实现快速、平稳和无静差的定点跟踪;微激励器环路的控制采用定值比例及滤波器,使得合并的位移输出能更快地跟踪目标磁道。仿真和实验结果验证了设计的有效性。

To provide faster and finer positioning of the read/write （R/W） head onto a target track, an additional piezoelectric microactuator （MA） is mounted on top of the existing voice-coil-motor （VCM） actuator, resulting in a so-called dual-stage hard disk drive （HDD） servo system. In the design of control system, the frequency characteristics of the piezoelectric microactuator are utilized to estimate its displacement and accordingly the displacement of the VCM. Then the controller for VCM is designed using an integral-enhanced robust and perfect tracking （RPT） control technology, which is capable of fast and smooth set-point tracking without static error. The microactuator is controlled through a simple static gain together with an appropriately designed filter. As a synergy effect, the dual stage servo system is able to perform faster tracking. Simulation and experimental results verify the effectiveness of this design.