Study on Design and Control of a Head Positioning Mechanism for High Servo Band Width

(A)高共振定位机构的设计本研究提出了基于同相振型概念的高共振定位机构。制作了定位机构的样机，并对其特性进行了实验研究。样机的最低振型为同相振动，其固有频率大于8.5 kHz。(B)定位机构的控制针对定位机构的简单模型设计了几种类型的H^∞控制器。利用这些模型研究了残余量和第二振型的固有频率对伺服带宽的影响。讨论了获得高控制伺服带宽的条件。在此基础上，设计了定位机构的H^∞控制器。仿真结果表明，该磁头定位系统的伺服带宽约为4 kHz。

(a)Design of High Resonance Positioning MechanismHigh resonance positioning mechanism based on the in-phase vibration mode concept has been proposed in this study. Prototype of proposed positioning mechanism was manufactured and its characteristics were investigated experimentally. The lowest vibration mode of the prototype was in-phase and its natural frequency was larger than 8.5kHz.(b)Control of Proposed positioning MechanismSome types of H^∞ controller have been designed for simple models of a positioning mechanism. Effects of magnitude of residue and natural frequency of the second vibration mode on the servo bandwidth have been investigated using these models. Conditions for high control servo bandwidth are discussed. Considering the conditions, a H^∞ controller has been designed for the proposed positioning mechanism. It was shown by simulation that the servo bandwidth of the head positioning system is about 4kHz.