Experimental verification of an optical beam stabilizing controller

2015 American Control Conference (ACC)

Turner

2015

This paper addresses the question of guaranteeing stability for a switching system. For this work, a switching system consists of a collection of subsystems with known LTI models and a switching signal that determines which subsystem model governs the system's dynamics at any given time. The switching signal may be the result of an operator's choice or a reaction to external events. Previous work has shown that the switching system will be stable if the switching signal is piecewise constant and dwells on each chosen value for some minimum period of time. Morse and Geromel have proposed methods for estimating an upper bound on the minimum dwell time from the realizations of the LTI subsystems. The new approach proposed in this paper utilizes the real Jordan form and produces a much more accurate estimate than Morse while requiring significantly fewer computations than Geromel. Numerical simulation of a switched system derived from an adaptive vibration attenuation controller illustrates the accuracy and computational efficiency of the proposed algorithm.

Section: A Adaptive Vibration Attenuation Applicationmentioning

confidence: 99%

On the computation of dwell time using the real Jordan form

2015 American Control Conference (ACC)

Turner

2015

“…To investigate the effect of the level of cross coupling on the closed-loop poles of the coupled system (2), the characteristic polynomial of this system is written as [4,5,13], the disturbance frequencies are assumed to well below the nominal bandwidth and, therefore, the presence of significant coupling does not invalidate this assumption.…”

Section: Transient Responsementioning

confidence: 99%

“…It is assumed that the disturbance frequencies are significantly smaller than the bandwidth of each FSM axis. The specifications on the control system design are to identify the dominant tonal frequencies and to attenuate the system's response at these frequencies while maintaining a positive noise margin 1 and, thereby, avoiding excessive spillover at high frequency [4,5,13,14].…”

Section: Optical Beam Stabilization Problem Statementmentioning

confidence: 99%

“…The estimates from the 5 th run are clear outliers and are not used in the computations below. To ensure the validity of the approximation in (13), the estimates are computed from the FFT data at the smallest disturbance frequency, 10 Hz.…”

Section: Experimental Verificationmentioning

confidence: 99%

“…In the previous work dealing with cross-coupling [10][11][12], the authors focused on control system design to reduce the effect of cross-coupling on positioning performance. The proposed algorithm provides the same capability and can be incorporated with adaptive (real-time) beam stabilization control [5] or with model-based (off-line) beam stabilization control [13]. In addition, the estimation algorithm can be utilized to estimate the relative orientation between the beam source platform and target platform, providing a useful tool for the calibration of platform-based sensors.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Cross-coupling estimation for optical beam stabilization

2012 American Control Conference (ACC)

Watkins

Thorp

2012

Self Cite

This paper presents a real-time algorithm for estimating the cross-coupling coefficients in a fast-steering mirror that serves as the actuator for an optical beam stabilization system. The algorithm computes the crosscoupling coefficients estimates by comparing the measured beam position with the predicted beam position from the uncoupled system model. This algorithm provides a means for estimating the relative orientation between the beam source platform and target platform as well. The algorithm is verified using experimental data from the United States Naval Academy Directed Energy Laboratory. 1 The noise margin is defined as the difference (in dB) between the largest amplitude of the identified tones and the largest amplitude at the frequencies above the tonal frequencies [5].

An anti-windup scheme for an adaptive ℋ<inf>∞</inf> vibration controller: Development and simulations

Turner

2015 American Control Conference (ACC)

2015

This paper presents a simple nonlinear anti-windup strategy for use in conjunction with a novel type of adaptive robust controller. In the absence of saturation constraints, the adaptive robust controller can provide highly effective disturbance rejection, but this ability is gradually lost as the saturation level is increased. In order to improve the performance of the controller during saturated periods, it is complemented with both a linear anti-windup compensator and a nonlinear modification of this compensator. Simulation results show that both anti-windup compensators are able to assist the adaptive robust controller in preserving vibration reduction levels when saturation is present, but that the nonlinear compensator is able to offer a higher level of vibration attenuation during periods of severe control signal saturation.