Computer Vision System and Experiment Design for Parabolic Flight Demonstration of Hard Disk Drives as CubeSat Reaction Wheels

Abstract

This thesis presents the design of a parabolic flight experiment and the development of the supporting systems to demonstrate hard disk drives functioning as CubeSat reaction wheels. Commercially available CubeSat reaction wheels are costly due to their precise manufacturing requirements, flywheel balancing, and limited amount of vendors. University-built CubeSat reaction wheels can prove to be failure-prone and time-consuming due to the expertise and machinery needed to manufacture, assemble, and test each unit. Through three years of research and testing, the Human/Robotics/Vehicle Integration and Performance (HRVIP) Laboratory in the UC Davis Center for Spaceflight Research (CSFR) developed a low-cost, reliable, readily available solution to the CubeSat reaction wheel cost versus risk trade-off by repurposing hard disk drives (memory storage devices commonly used in laptops) as CubeSat reaction wheels. Testing the Hard Disk Drive Reaction Wheels (HDD-RWs) in parabolic flights allowed for characterization of their performance in the fully unconstrained free-floating environment of microgravity. The design of the parabolic flight experiment system is presented, herein, with a focus on design for human operation and safety in the dynamic flight environment. Five CubeSat testbeds, each containing HDD-RWs, were developed for testing in the parabolic flights, and a supporting computer vision system was designed utilizing ArUco markers for external attitude determination of the CubeSat testbeds. The measurement accuracy and noise of the computer vision system was characterized on-ground through precise placement of the ArUco markers with a UR5e robot arm. Flight data from the computer vision system was integrated into an Extended Kalman Filter and shown to validate the CubeSat testbed onboard attitude determination method. Through the parabolic flight experiment and data validation with the supporting computer vision system, the Technology Readiness Level of the HDD-RWs was raised from TRL 4 (component and/or breadboard validation in laboratory environment) to TRL 6 (system/subsystem model or prototype demonstration in a relevant environment). HDD-RWs were shown to be a promising alternative to commercial and in-house built CubeSat reaction wheels.