Incremental Nonlinear Fault-Tolerant Control of a Quadrotor With Complete Loss of Two Opposing Rotors

Abstract

In order to further expand the flight envelope of quadrotors under actuator failures, we design a nonlinear sensor-based fault-tolerant controller to stabilize a quadrotor with failure of two opposing rotors in the high-speed flight condition (> 8m/s). The incremental nonlinear dynamic inversion (INDI) approach which excels in handling model uncertainties is adopted to compensate for the significant unknown aerodynamic effects. The internal dynamics of such an underactuated system have been analyzed, and subsequently stabilized by re-defining the control output. The proposed method can be generalized to control a quadrotor under single-rotor-failure and nominal conditions. For validation, flight tests have been carried out in a large-scale open jet wind tunnel. The position of a damaged quadrotor can be controlled in the presence of significant wind disturbances. A linear quadratic regulator (LQR) approach from the literature has been compared to demonstrate the advantages of the proposed nonlinear method in the windy and high-speed flight condition.

Autonomous Quadrotor Flight Despite Rotor Failure With Onboard Vision Sensors: Frames vs. Events

“…The authors of [2] considered the initial spinning phase with varying yaw rate, using a linear parameter varying controller. As the above controllers did not consider aerodynamic effects, the INDI approach was applied in [3] and [4] to render the controller resilient to significant aerodynamic disturbances in high-speed wind-tunnel flight tests.…”

“…Note that this controller is modified from that in [4] to avoid using motor speed measurements unobtainable for some platforms. As a consequence, this controller is less robust against model mismatch caused by, e.g., high-speed induced aerodynamic effects.…”

“…As a consequence, this controller is less robust against model mismatch caused by, e.g., high-speed induced aerodynamic effects. If the rotor speeds are measurable, we refer readers to use the controller proposed in [4] to improve the resilience against aerodynamic disturbances.…”

“…Previous works have achieved autonomous flight of a quadrotor subjected to complete failure of a single rotor [1], [2], and even in high-speed flight conditions where aerodynamic disturbances are apparent [3], [4]. However, these methods rely on external sensors, such as GPS or motion capture systems, for position tracking, which completely eliminate or alleviate the effects of state estimation errors.…”

Incremental Twisting Fault Tolerant Control for Hypersonic Vehicles With Partial Model Knowledge

“…To handle such a dilemma, the incremental nonlinear dynamic inversion (INDI) was proposed in [16] and has attracted much attention for the FTC design in the aerospace community [17,18,19]. Recent flight tests [20,21] have also demonstrated the applicability and efficiency of this method. The main advantage of INDI is that not only the model dependency is reduced, but also the robustness is improved.…”