FURTHER INVESTIGATION OF ELASTIC MODE EFFECTS ON CLOSED-LOOP STABILITY OF A WINGED BOOSTER.
Abstract
This report is devoted to a closed-loop analysis of the dynamic interaction of elastic and rigid body modes for a large booster in the ORION class. A variety of possible first and second elastic mode shapes is assumed along with three different sensor locations. Closed-loop dynamics are determined for all combinations of these conditions and for a wide variation in autopilot, actuator, and rate gyro gains. The interaction is shown to be very severe on both the shortperiod and elastic modes. For all cases considered, regardless of the gains used, the real roots corresponding to the first-order actuator and rate gyro time constants were positive, indicating instabilities. It is also shown analytically that there is no combination of actuator, autopilot, and gyro gains which would stabilize the stated system. In addition, the short-period characteristics are very insensitive to orders-of-magnitude variations in system gains. These surprising results mean that conventional sensing and feedback control with single actuation would not be suitable for this vehicle. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1963
- Accession Number
- AD0605156
Entities
People
- Robert L. Swain
Organizations
- Flight Dynamics Laboratory