Experimental validation of L₁ adaptive control: The Rohrs counterexample in flight

This paper presents flight-test results that examine the performance and robustness properties of an L₁ control augmentation loop implemented onboard a small unmanned aerial vehicle. The framework used for in-flight control evaluation is based on the Rohrs counterexample, a benchmark problem presented in the early 1980s, to show the limitations of adaptive controllers developed at that time. Hardware-in-the-loop simulations and flight-test results confirm the abilityofthe L₁ flight control systemtomaintain stability and predictable performance ofthe closed-loop adaptive system in the presence of general (artificially injected) unmodeled dynamics. The results demonstrate the advantages of L₁ control as a robust adaptive control architecture with the potential of facilitating the transition of adaptive control into advanced flight control systems.