Quadrotor Attitude Control using Incremental Nonlinear Dynamics Inversion
Given the large flight envelope of vertical take-off and landing vehicles, and the nonlinear nature of multirotor aircraft, especially in aggressive maneuvering, nonlinear control strategies are often considered. Yet, most available solutions are model dependent and thus require a precise knowledge of the system dynamics, including the hard to model aerodynamics. This paper proposes a sensor-based approach to the problem. It considers a recent strategy based on incremental control and Nonlinear Dynamics Inversion (NDI), the Incremental Nonlinear Dynamics Inversion (INDI), to solve the attitude control problem of quadrotors. The INDI general formulation is presented, and then applied considering the attitude stabilization of a quadrotor. In order to apply the INDI solution to this case study, a linear predictor for the angular acceleration is provided. Simulation results demonstrate the robustness of this sensor-based approach to model-parameter uncertainties and wind disturbances. An analysis is also done regarding the tuning of INDI parameters and its sensitivity to the chosen sampling time.
Stabilization and Altitude Control of an Indoor Low-Cost Quadrotor: Design and Experimental Results
Included in the Quadr-ANT project, this work builds on previous developments towards an indoor low cost Arduino-based quad rotor, capable of stabilized flight with altitude control. A simulator with experimentally identified parameters allows to test and tune the developed Kalman estimators and LQR controllers for altitude and attitude stabilization. The validated solutions were implemented on the onboard Arduino and demonstrated on experimental flights of the quad rotor prototype. The steps and data required to build a realistic quad rotor simulator are provided.
Knocking in an Internal-Combustion Engine
The question remains open of the relation between the phenomena of knocking in the engine and the explosion wave. The solution of this problem is the object of this paper. The tests were conducted on an aircraft engine with a pyrex glass window in the cylinder head. Photographs were then taken of various combinations of fuels and conditions.