Experimental Validation of L1 Adaptive Control: The Rohrs Counterexample in Flight

Abstract

This paper presents flight-test results that examine the performance and robustness properties of an L 1 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 ability of the L 1 flight control system to maintain stability and predictable performance of the closed-loop adaptive system in the presence of general (artificially injected) unmodeled dynamics. The results demonstrate the advantages of L 1 control as a robust adaptive control architecture with the potential of facilitating the transition of adaptive control into advanced flight control systems.

A novel application of multivariable &#x2112;<inf>1</inf> adaptive control: From design to real-time implementation on an underwater vehicle

“…This control scheme is able to revisit the failures of other adaptive controllers by maintaining its performance and robustness in situations where the other controllers cannot [15] [16]. The L 1 adaptive controller has been validated through simulations and experiments mainly on aerial vehicles [17] [18], but it was also seen in other applications such as the control of the acrobot [19] and the hysteris in smart materials [20]. The main contribution of this paper is the experimental demonstration of a new application of this controller which concerns depth and pitch control of an underwater vehicle.…”

L1 Adaptive depth and pitch control of an underwater vehicle with real-time experiments

“…This controller can ensure a good performance with zero parameter initialization and without any necessity for a specific excitation. It is worth to note that, to the best knowledge of the authors, this control scheme was mainly applied to aerial vehicles (Dobrokhodov et al, 2010) (Kaminer et al, 2010) and mechatronic systems (Techy et al, 2007) (Fan & Smith, 2008) and has never been applied yet to underwater vehicles. We propose in this paper the theoretical aspects of the de-sign of an L 1 adaptive controller to be applied for the first time on an underwater vehicle.…”

SLUGS UAV: A flexible and versatile hardware/software platform for guidance navigation and control research

“…Currently UAVs are being actively used to conduct research in fault-tolerance [1], adaptive control [2], trajectory tracking [3], path following [4], and cooperative control [5].…”

“…The system monitors the signal coming out of the RC receiver onboard the airplane 2 , and uses this signal to pass the RC signals directly to the control surfaces or allows SLUGS to control them. The failsafe is completely self contained; it does not share power or other components with the SLUGS board, but rather runs off of the critical systems power bus which powers the main motor and the RC servos.…”