Input-Output Linearization of Longitudinal Flight Dynamics Bypassing Unstable Zero Dynamics                 

Summary

 

The project is a report on a paper published by J. Delgado. Traditional input-output linearization (IOL) methods struggle with systems where the number of outputs exceeds the number of inputs due to unstable zero dynamics. The paper focuses on circumventing these issues within the context of longitudinal flight dynamics of aircraft, where inputs typically include thrust and elevator deflection, and outputs are velocity and flight path angle. The paper extends IOL methods to non-square systems by incorporating additional outputs to eliminate unstable zero dynamics, thus allowing for successful linearization. The approach involves using multi-input, multi-output (MIMO) systems and applying transformations to linearize the input-output relationship, even in the presence of more complex dynamics. ​Here, an additional output, pitch angle, is introduced to the system, resulting in successful linearization and stabilization even in scenarios that typically challenge standard input-output linearization techniques due to having more outputs than inputs. The method is validated using numerical simulations demonstrating trim conditions at various aircraft velocities and trajectory of output state and input over time using MATLAB

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