Multi-stage micro rockets for robotic insects

One of the main challenges for sustained flight of current aerial micro robots is the low energy density available from common power sources. In this paper we propose solid rocket fuel powered micro thrusters as a high energy density actuation method for aerial micro robots. In a multi stage configuration these thrusters can be used for intermittent flight which can decrease the energetic cost of locomotion. In particular we focus on the fabrication method and characterization of multi-stage micro thrusters with a diameter of 3mm and 6.4mm. We demonstrate a sustained and repeatable thrust force of up to 35mN for a duration of up to 42s and a multi-stage designs with a time delay of up to 4.7s between the propulsion phases. Furthermore, we present a take-off trajectory of a 10cm rocket glider with an integrated micro thruster as propulsion mechanism showing that the technologies developed can be used to successfully power micro robots in flight. Future work will focus on control and flight dynamics of micro thruster powered gliders. Wider applications of similar thrusters can include other robotic applications where low weight and high force is important such as for jumping or running robots.