Global Jitter Control Design for Integrated Opto-mechanical Systems

On an airborne weapon system such as Airborne Laser (ABL), on-board vibrations distributed throughout the beamtrain result in line-of-sight jitter and significant degradation of weapon lethality. Conventional beam control implements several independent cascaded control loops, with local loops operating to reduce jitter in a particular portion of the beam train. Implementation and design are relatively quick, but significant analysis and re-specification of servo parameters is necessary to attain more optimal performance that accounts for stroke and torque constraints and that is tuned for specific disturbance spectra. To more aggressively improve line-of-sight jitter, a global approach to the problem is recommended. The approach is to treat the jitter and beamwalk system as an integrated opto-mechanical structure and to control active mirrors using a regulator-estimator methodology combined with feedforward adaptive filtering. In Phase I a control system using this global approach will be developed and compared to open-loop and conventional control system models. Several metrics will be evaluated including line-of-sight jitter, beamwalk, mirror stroke and control authority, and propagation of noise into jitter. In Phase II, the coordinated global control design will be applied to a high fidelity control system testbed, and details of practical physical implementation will be determined.