Design and analysis of an active gimbal simulator with three degrees-of-freedom for ground testing

Abstract

In this paper, a new active gimbal simulator is developed for testing the attitude determination and control system of satellites. The active gimbal simulator is composed of a rolling joint, a pitching joint, a main support frame, an active yawing joint, and a fixture. The rolling joint enables the active gimbal simulator to be applied to the columnar satellite without the fixture. The contact forces between the rolling joint and the test satellite (or the fixture) can be regulated by the support of the pitching joint. The object attached to the active gimbal simulator is at neutral equilibrium and can maintain balance at an arbitrary attitude. Hence, the object can rotate freely without being affected by its gravity. The active gimbal simulator is an approximately free-to-free suspension or support method. Compared with the traditional gimbals, the active gimbal simulator can be applied to objects of arbitrary shape especially cylinders and the effect of exogenous mass and inertia introduced by the connection mechanism is reduced. The design parameters of the active gimbal simulator are optimized based on the force analysis. A specific prototype was made, and its feasibility was verified by laboratory-based experiments.