This project presented the design, analysis, control, and implementation of a novel, ultra-lightweight spherical aerial-terrestrial robot (ATR). The design of the ATR is comprised of a micro-quadcopter encased in a 6 inch spherical exoskeleton. The ATR has the ability to y through the air or roll on the ground, for various applications such as inspection, surveillance, mapping, and search and rescue. The developed ATR is currently the smallest quadcopter-based hybrid locomotive robot and is especially suited for urban applications in tight spaces that require a high degree of maneuverability.
The dynamic system model is presented for both modes of locomotion, and then utilized to generate control parameters and inputs to demonstrate hybrid locomotion. Experimental results show that the synthesized ight controller is capable of stabilizing the attitude of the ATR in both modes of locomotion, and input tracking is 1.47 percent RMS error in aerial mode. The ATR is experimentally tested and proves capable in autonomous modes such as throw-to-hover, open loop aerial trajectory tracking, roll-to- y maneuvers, and demonstrates the capability to perform a turn while rolling.
The general deviation from desired paths in both terrestrial and aerial trajectories is likely due to effects not captured by the formulated model such as: aerodynamic effects, motor thrust dynamics and nonlinearities, system compliance, and external disturbances. Results from open-loop trajectory tracking can be improved with the addition of an external localization system used for position feedback control. Then, instead of controlling only the attitude of the ATR, precise position control can be implemented.
This code has a document (124pages) which describes the algorithm in detail.