Applied Mass Properties Identification Method to the Cal Poly's Spacecraft Simulator

Author

Long H. Dam, California Polytechnic State University, San Luis ObispoFollow

DOI: https://doi.org/10.15368/theses.2014.25
Available at: https://digitalcommons.calpoly.edu/theses/1175

Date of Award

4-2014

Degree Name

MS in Aerospace Engineering

Department/Program

Aerospace Engineering

Advisor

Eric Mehiel

Abstract

The Cal Poly Spacecraft Simulator is currently being developed for future testing and verifying theoretical control applications. This paper details the effort to balance the platform and remove undesired external torque from the system using System Identification technique developed by Patrick Healy. Since the relationship between the input and output of the system is linear, the least square method is proposed to identify the mass properties and location of center of mass of the system. The tests use four sine wave generators that are out of phase with different amplitudes as the inputs to excite various structural modes of the system. The outputs, angular rates of the platform, are measured by the newly implemented LN-200 Inertial Measurement Unit that helps reducing the measurement noise. Two test cases of 90^o yaw rotations with the identified inertia were performed and validated against the computer simulation model; and the result shows that the test cases trajectories followed closely with the computer simulation model.