Wind-up AUVs: Combined energy storage and attitude control using control moment gyros

This research develops a system to combine energy storage and attitude control functions in control moment gyros (CMGs) for application onboard autonomous underwater vehicles (AUVs). This is proposed as part of a hybrid energy storage system to allow AUVs to perform their missions with no chemical batteries at all. In previous works, the authors developed an attitude control scheme based on the gyroscopic torques developed by a cluster of four CMGs, which was implemented onboard the test-bed AUV ´IKURA´, and successfully demonstrated full three-dimensional attitude control capabilities. This paper extends the control scheme to overcome interactions between the kinetic energy and angular momentum stored in the CMG flywheels, to allow the energy mechanically stored in the rotation of the flywheels to power the electronics of the robot, while simultaneously controlling its three-dimensional attitude. The control scheme is implemented on a four unit CMG pyramid developed for IKURA and series of land experiments are performed to demonstrate simultaneous energy transfer and attitude control.