Rotational Motion Platform for Emulating Spacecraft Attitude Control

Abstract

This research develops and evaluates a robotic rotational motion platform to test lunar-landing-like attitude, sensing and control. The platform is equipped with thrusters, sensors, and computer control and is restricted to orientation maneuvers. The platform is mass balanced and suspended on a bearing that accommodates 60 degrees of excursion in roll, pitch and yaw. The platform operates in a controlled indoor environment where one spotlight represents the sun, another represents earth and a pattern on the floor represents a star field. Sensor fusion and control are accomplished and motion is commanded. The robot follows intended attitude trajectories with high fidelity. Fused sensor data exhibits superior pose estimation beyond what is possible with any single sensor. This platform emulates the actuation capabilities of spacecraft, such as Apollo 11 landers, CLEMENTINE lunar orbiter and the Space X Dragon, which use attitude thrusters as a means for attitude control. This research illustrates that a propulsive roll, pitch, yaw platform with scaled mass properties of a lunar lander can emulate attitude trajectories required for cruise, entry, descent and landing on the moon.