- 學位論文
具傾角控制光學讀寫頭之Mu合成控制分析
Mu-synthesis analysis in the optical pickup head with tilting control system
摘要
在高畫質及高容量的DVD技術中，極重要的便是加強其光學讀寫頭的循軌讀片性能。除了傳統的聚焦及循軌控制外，近代光學頭已具備了傾角補償能力來針對外界的干擾做為補償，如光碟片的徑向傾角…等。本論文描述了光學讀寫頭三個自由度的動態系統模型，且當傾角致動器作用時，傾斜角度會導致非線性動態行為，且系統的耦合效應就會出現，因此系統就變得極難控制。而傳統的伺服控制系統幾近於使用獨立分開的控制迴路設計，且通常會忽略系統之間的耦合效應。本文旨在建立一模擬系統，其可表示出系統動態不確定性，並將不確定性結構化，以用較方便的μ合成控制器設計來完成光碟機系統的強靭控制性能。模擬結果也證明了用μ理論求得的控制器能夠在極大的外界干擾下仍能夠正常工作，而原控制器並無法達成。此一完整的系統設計期望能提供給研究者來實行。
並列摘要
Recent advancement in the high-definition digital versatile disk technique has imposed stringent demand on the optical pickup head tracking performance. In addition to focus and tracking control, the optical pickup head comes with tilt compensation capability is also becoming popular to compensate for the disk radial tilt. This thesis describes the dynamic modeling of the three degree-of-freedom optical pickup head actuator. The tilting angle in the pickup head system resulted in highly nonlinear dynamic behavior and the coupling effect will appear when tilt actuator actions, therefore, the system becomes very difficult to control. The conventional servo design approaches had been using separate control loops, and had often neglected the coupling effect. This thesis proposes a formulation to express the change in the dynamic behavior by some structured system uncertainties. The popular Mu-controller synthesis technique can then help to design a robust tracking controller. The simulation result shows that the proposed controller capable to operate under very extreme disturbances while the conventional controller can’t achieve. The systematic design procedure is also straight forward for the practice engineers to carry out.