An Intuitive, Aggressive Control Architecture for an Unmanned Helicopter in Near-Hover Flight

Control system design for unmanned helicopters has become a widely studied topic, resulting in numerous design techniques with varying qualities. Many control designs rely on precise knowledge of the highly non-linear system dynamics inherent in a helicopter, and resulting techniques suffer from gain margin issues associated with the effect of the designed control laws on the variable system modes. A robust and heuristically defined control system structure is proposed that can be theoretically designed and empirically tuned in the field based on observed responses. The design is implemented as successively closed loops with four tiers to ensure stability and ease of design. The control architecture presented illustrates a theoretically robust system that, when used with analytic models and low control gains, provides implicit system controllability and stability open to optimization by means of various control techniques. The structure is intended and designed for outdoor operation in near-hover flight, and practical results are given for tests completed in an outdoor environment.