Optimal Control for Lunar Tumbling Robot

JOOEE is a cube-shaped lunar robot with a simple yet robust design. JOOEE ishermetically sealed from its environment with no external actuators. Instead, JOOEE spins three internal orthogonal flywheels to accumulate angular momentum and uses a solenoid brake at each wheel to transfer the angular momentum to the body. This procedure allows JOOEE to jump and hop along the lunar surface. The sudden transfer in angular momentum during braking causes discontinuities in JOOEE’s dynamics that are best described using a hybrid control framework. Due to the irregular methods of locomotion, the limited resources on the lunar surface, and the unique mission objectives, optimal control profiles are desired to minimize performance metrics such as time, energy, and impact velocity during different maneuvers. This paper details the development of an optimization tool that can handle JOOEE’s dynamics including the design of a hybrid control framework, dynamics modeling and discretization, optimization cost functions and constraints, model validation, and code acceleration techniques.