Passive height stability and trajectory repeatability of a quadrotor maneuvering in ground effect with regulated voltage bus

Passively stable aerodynamic systems are able to regulate their flight without need for additional sensing or actuation. Passive rotorsurface interaction provides a mechanism for repelling a rotorcraft away from the ground and surrounding objects. However, the vertical dynamics of a helicopter are very sensitive to battery voltage, which makes developing these systems more challenging. There is a need to maintain a constant motor bus voltage so that the response of the system is consistent. We employ a step-down buck regulator to maintain a constant voltage for the entire drive system of a miniature quadrotor. This allows us to better study the power efficiency of a quadrotor in ground effect, demonstrate robust passive height stability and determine the influence of voltage variability on trajectory repeatability.