The Omnirotor Platform: A Versatile, Multi-Modal, Coaxial, All-Terrain Vehicle.

Mobile and aerial robots offer many potential applications, including warehouse logistics, surveillance, cinematography, and search and rescue. However, most such robots are task-specific and generally lack the versatility to tackle multiple scenarios, terrains, and unstructured, dynamic environments. This paper presents the Omnirotor platform, a versatile, multi-modal, coaxial, tilt-rotor, all-terrain vehicle that combines an Unmanned Aerial Vehicle (UAV) and an Unmanned Ground Vehicle (UGV) into a hybrid, all-terrain vehicle. The Omnirotor has two locomotion modes of operation (aerial and ground vehicle) and five operational configurations, as it can fly both in the Normal and Inverted configurations and drive on the ground in the Normal and Inverted configurations. It can also recover from any non-operational state to its Normal, upside-down configuration. Moreover, in addition to the locomotion modes, the continuous omnidirectional thrust vectoring enables the Omnirotor platform to perform complex manipulation of objects. This work introduces the concept and discusses in detail the design, development, and experimental validation of the Omnirotor platform. In particular, it discusses the modeling and control schemes required by the different operation modes and configurations. It experimentally validates the platform's capabilities with experiments focusing on traversing challenging environments and unstructured, uneven terrains (e.g., a public park). Finally, the platform's ground, pushing-based manipulation capabilities are demonstrated through the execution of a puzzle-solving experiment where the solved puzzle serves as a landing platform for the all-terrain vehicle. The versatility of the Omnirotor offers exciting prospects for use in challenging search-and-rescue scenarios, surveillance, and aerial and ground manipulation applications.