  The standard quadrotor is one of the most popular and widely used aerial
vehicle of recent decades, offering great maneuverability with mechanical
simplicity. However, the under-actuation characteristic limits its
applications, especially when it comes to generating desired wrench with six
degrees of freedom (DOF). Therefore, existing work often compromises between
mechanical complexity and the controllable DOF of the aerial system. To take
advantage of the mechanical simplicity of a standard quadrotor, we propose a
modular aerial system, IdentiQuad, that combines only homogeneous
quadrotor-based modules. Each IdentiQuad can be operated alone like a standard
quadrotor, but at the same time allows task-specific assembly, increasing the
controllable DOF of the system. Each module is interchangeable within its
assembly. We also propose a general controller for different configurations of
assemblies, capable of tolerating rotor failures and balancing the energy
consumption of each module. The functionality and robustness of the system and
its controller are validated using physics-based simulations for different
assembly configurations.
