Microelectromechanical systems (MEMSs) pose unique measurement and control problems compared with conventional ones because of their small size,low cost,and low power consumption.The vibrating gyroscope is one of those MEMS devices that have significant potential in many industry applications.When the MEMS gyroscope system is considered simultaneously with the coupling terms,the exogenous disturbances and the parameter variations,the controller design of this system becomes very challenging.This paper investigates the primary control problem of a perturbed vibrating MEMS gyroscope.A nonlinear robust adaptive control scheme is proposed for the drive axis of a vibrating MEMS gyroscope.By combining the dynamic surface control (DSC) method with the H-infinity disturbance attenuation technique,a simpler systematic design procedure is developed.The derived H-infinity controller has a simplified structure,and it can drive the drive axis to resonance,regulate the output amplitude of the drive axis to a desired value,and attenuate the generalized disturbances.The features of the derived controller are discussed and illustrated by the simulation of a closed-loop system.The analysis and simulation show that the obtained controller possesses good adaptability and robustness to system uncertainties.
为了解决无线传感器网络汇聚节点存在的溢出问题,基于α-稳定分布和令牌桶建立了一种新的接纳控制方法(connection admission control based onα-stable and token bucket,CACαTB)。该方法首先给出了网络演算中服务曲线与到达曲线的定义,然后利用α-稳定分布推导了令牌桶的控制参数,并建立面向分形业务流的接纳控制算法。最后利用NS2进行实验仿真,深入研究了丢包率、带宽利用率、缓冲区、以及分形参数之间的关系。与其他方法相比,结果发现CACαTB具有较好的适应性。
