Revised semi-empirical aerodynamic estimation for modelling flight dynamics of an airship

Modelling of dynamics of an airship is essential in the prediction of the flight characteristics, stability analysis and the design of control laws for autonomous operation. In the dynamics model that was proposed by Ashraf and Choudhry [1], deviations were observed between the simulation results and the validation data since the lengths and areas associated with the calculation of aerodynamic coefficients were not normalised. This paper documents the revisions proposed to the incorporation of semi-empirical aerodynamic estimation technique in the dynamics modelling of an airship as well as the normalisation of aerodynamic coefficients. Simulations are performed on the revised airship dynamics model and are compared with the simulation results of preceding models. A satisfactory agreement is seen between the revised model and the validation data, both in terms of magnitude and trends.