Real-time computer control of a flexible spacecraft emulator

A description is given of a ground-based test facility named Daisy, which was established to study control issues for large flexible spacecraft. The validation of modern algorithms for system identification and shape and attitude control and the development of new control devices can be performed using Daisy. The experimental structure consists of a radial mesh of ribs attached flexibly to a rigid hub. The structure is instrumented with position and rate sensors and controlled by a real-time computer and data acquisition system by means of torque actuators. The more important aspects of these subsystems and their integration are presented along with experimental results for a baseline controller, consisting of a simple integral-derivative feedback control on the position of the hub.<>