Minimum impulse limit cycle design to compensate for measurement uncertainties
Edward T. Kubiak, Mikael Martin · Journal of Guidance Control and Dynamics · 1983
A new design was developed for the Space Shuttle transition phase digital autopilot to reduce the impact of large measurement uncertainties in the rate signal during attitude control. The signal source, which was dictated by early computer constraints, is characterized by large quantization, noise, bias, and transport lag that produce a measurement uncertainty larger than the minimum impulse rate change. To insure convergence to a minimum impulse limit cycle, the design employed bias and transport lag compensation and a switching logic with hysteresis, rate deadzone, and walking switching line. The design background, the rate measurement uncertainties, the design solution, and the performance improvement are presented in this paper.