Model reference control of a laser beam steering system for laser communication applications

2001 ◽  
Author(s):  
Mounir Bouzoubaa ◽  
Vladimir V. Nikulin ◽  
Victor A. Skormin ◽  
Timothy E. Busch
Keyword(s):  
Laser Beam ◽  
Beam Steering ◽  
Steering System ◽  
Laser Communication ◽  
Model Reference ◽  
Model Reference Control

Disturbance Rejection by Optimal Feedback Control in a Laser Beam Steering System

2004 ◽  
Author(s):  
Pawel K. Orzechowski ◽  
Steve Gibson ◽  
Tsu-Chin Tsao
Keyword(s):  
Control System ◽  
Laser Beam ◽  
Disturbance Rejection ◽  
Beam Steering ◽  
Control Design ◽  
Steering System ◽  
Optimal Feedback Control ◽  
Stochastic Disturbances ◽  
Linear Quadratic ◽  
Position Sensing

This paper presents an optimal control design and experimental implementation for pointing and disturbance rejection in a laser steam steering system. The linear quadratic Gaussian (LQG) controller, which includes a stochastic disturbance model, as well as integral action, was designed and implemented to compensate for disturbances due to atmospheric turbulence in the optical path and mechanical vibration of the laser and optical components. The control design also considers the situation where the stochastic disturbances applied to the two beam axes are correlated and renders a multi-input-multi-output (2-by-2) output feedback controller. The experimental system consists of a two-axis tilt mirror driven by piezo-electric actuators for controlling the laser beam, a second actuated tilt mirror to generate disturbances, a position sensing device that senses the location of the beam on a target plane, and a real time computer for digital control. System identification is used to determine a state space model of the beam steering system for use in control system design. Experimental results are presented to demonstrate the effectiveness of the LQG optimal disturbance rejection for the prescribed stochastic disturbances.

Four Wheel Steering System for Vehicle Handling Improvement: A Robust Model Reference Control Using the Sliding Mode

1996 ◽  
Vol 210 (4) ◽  
pp. 335-346 ◽  
Author(s):  
P I Ro ◽  
H Kim
Keyword(s):  
Sliding Mode Control ◽  
Sliding Mode ◽  
Direct Method ◽  
Steering System ◽  
Slip Angle ◽  
Model Reference ◽  
Vehicle Handling ◽  
Yaw Rate ◽  
Mode Control ◽  
Model Reference Control

In this paper a MIMO model reference control scheme incorporating the sliding mode control theory for a vehicle four wheel steering system is proposed and evaluated for a class of continuous-time non-linear dynamics with uncertainties. By the Lyapunov direct method, the algorithm is proven to be globally stable, with tracking errors converging to the neighbourhood of zero. The sliding mode four wheel steering (SM4WS) not only improves the directional stability and responsiveness but also provides good disturbance rejection for unexpected side wind. The SM4WS results in a faster vehicle response than conventional two wheel steering (2WS) without suspension and tyre modification. The linear three degree-of-freedom vehicle handling model is used to investigate vehicle handling performances. In simulation of the J-turn, the yaw rate overshoot reduction of a typical mid-size car improved by 30 per cent compared to a 2WS case. Although the lateral deviation of SM4WS is almost the same as that of 2WS the yaw rate reduction was approximately 20 per cent of that of a 2WS system. The simulation of the J-turn manoeuvre shows that the proposed scheme gives faster yaw rate response and smaller slide-slip angle than the 2WS case. When the rear tyre pressure is lower than normal, the car has less understeer and is worse in directional responsiveness, while SM4WS is insensitive to such parameter variations because of the robustness characteristics of the sliding mode control.

Note: High capacity digital laser beam steering system

2011 ◽  
Vol 82 (11) ◽  
pp. 116101 ◽  
Author(s):  
D. Hebert ◽  
P. Cantu ◽  
C. Washington ◽  
O. Ajala ◽  
M. Feldman
Keyword(s):  
Laser Beam ◽  
Beam Steering ◽  
High Capacity ◽  
Steering System
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