Modeling and Control Performance Evaluation for Testbed of Asteroid Flyby Observation System

A flyby is a mission that a spacecraft passes a planet or an asteroid in space to acquire fruitful information through observation. In the mission, an imaging system with a tracking device should be stably pointed in the direction of the asteroid to take physically significant images. This paper investigates the feasibility of the flyby mission through the testbed of the tracking device. From the viewpoint of compact size, lightweight, and high-accuracy transmission, a strain wave gearing is used in the actuation system. In this study, a testbed of the tracking mirror-driven system using the strain wave gearing is designed to conduct preliminary tests before the actual mission. For the model-based design and detailed verification in the design stage, an accurate numerical simulator is developed by considering the nonlinearities such as nonlinear friction and angular transmission error in the strain wave gearing. The feasibility of the mission is discussed based on the numerical simulations and experimental results using the testbed and expected tracking trajectory of the mission.