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Flex pivots introduce very low coulomb and viscous friction coupling making possible a -40 dB/dec roll-off in the position closed loop (mass stabilization) . This roll-off, beginning at about 2 Hz, increase possible the increase in stabilization from the outer to the inner set. However, special attention must be given to the effects of the relatively large spring rate coupling associated with flex pivots. For the system considered, the flex pivot gimbal resonance limits the minimum bandwidth to 3.5 Hz using conventional derivative control. This paper discusses a positive feedback solution implementing band limited derivative control to compensate for the flex pivot resonance while minimizing the bandwidth to 2.0 Hz for an additional 11 dB of attenuation above 3 Hz. Trade-off studies are discussed and a closed form solution is presented which solves for the compensator parameters as a function of flex pivot stiffness, plant characteristics, and desired bandwidth. Three examples are presented. |
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Control systems
Electroluminescence
Actuators
Signal attenuation
Image sensors
Sensors
