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We describe a protocol for the use of a control feedback loop incorporating an iterative optimization routine for a range of time-independent adaptive optics applications. These applications are characterized by the quasi steady state of the aberrative effects (>0.1 s) and contrast, for instance, to astronomical applications where the aberrations constantly vary at frequencies above 10 Hz. For optimal performance in such time-independent applications, the control systems typically require specialized tailoring. A typical example of two different types of time-independent adaptive optics applications--an adaptive optic microscope and an adaptive optic laser platform--are detailed and compared. It is shown that implementing a number of minor, but crucial, application-specific modifications to the control system results in an improved efficiency of an already extremely successful technique for aberration compensation. We present a description of the crucial parameters to consider in a search-based adaptive optics system. [c] 2010 Optical Society of America OCIS codes: 010.1080, 180.1790, 140.6810.

We report a double feedback loop for the improvement of the carrier-envelope phase stabilization of a chirped mirror based femtosecond laser oscillator. By combining the control of the Ti:sapphire crystal temperature and the modulation of the pump power, the carrier envelope offset frequency, f CEO, was locked for close to 20 h, which is much longer than the typical phase stabilization time with only pump power modulation. OCIS codes: 320.7090, 320.7100, 320.7160.

The application and validation of a simple closed-loop control scheme which could be used to achieve stable large-amplitude motion of a resonant structure even in presence of jump resonance in frequency response are discribed. The proposed feedback scheme ensures the stability of the motion of the beam much beyond the critical Duffing amplitude and also revealed the correct choise of beam parameters to achieve almost full-gap travel range without incurring electrostatic pull-in.

Byline: Jun-Wu Shi, Xiao-Wei Li, Jian-Wu Zhang Based on modelling and experimental validation of the hydropneumatic spring, a non-linear dynamic model is developed for the active hydropneumatic suspensions of missile launching vehicle. In order to fulfil the special requirements of mobile launching, the non-linear system is transformed into a linear one by means of feedback linearisation (FBL) according to the theory of differential geometry. Furthermore, a PID control approach is applied for the solution to the system of equations. It is indicated by the simulation results that the present non-linear controller combining the FBL with linear control algorithm is characterised with its fairly simple structure and good performance.