Transient Response Problems

Transient factors imposed on the vehicle from various sources may initiate structural responses which can interact with the control system. Thrust transients. Thrust transients e.g., engine ignition, engine shutdown, and uneven burning can create significant loads or vibration levels. These can cause overall or local response of the vehicle resulting in structural feedback to the control system see ref. 26 . For instance, unsynchronized burnout of pairs of solid propellant engines, such as used...

Structural Feedback Problems

Cantilever Beam With Three Bending Modes

The most common structural feedback problems are those in which either gross vehicle or local body oscillations are reinforced by the control system. Sensor location. Improper sensor location can result in structural feedback problems. An idealized representation of a beam-like space vehicle deflected in its fundamental bending mode is shown in figure 3. Typically, an angular motion sensor, such as a rate gyro, senses structural pitch deflections. When these deflections are added to rigid-body...