58 Int. J. Powertrains, Vol. 8, No. 1, 2019 Copyright © 2019 Inderscience Enterprises Ltd. Computerised symbolic planetary transmission modelling for automotive design Christos Spitas* and Andas Amrin School of Engineering, Nazarbayev University, Astana, Kazakhstan Email: cspitas@gmail.com Email: andas.amrin@nu.edu.kz *Corresponding author Amin Amani ASML, Eindhoven, Netherlands Email: amin.amani81@gmail.com Georgios Vasileiou and Vasileios Spitas School of Mechanical Engineering, National Technical University of Athens, Athens, Greece Email: gvasileiou@mail.ntua.gr Email: vspitas@central.ntua.gr Abstract: A method and its computerised implementation are proposed for the modelling of planetary transmission systems. Using a computer symbolic scripting environment, a number of idea class objects and appropriate methods to manipulate them are defined, implementing all the relationships that govern the system kinematics, mechanical efficiency and geometric compatibility. The outcome is a system of equations involving the most pertinent design and performance parameters, which allow a systematic interrogation of the relationships between system design and performance. This method is particularly useful for the synthesis and design of novel automotive planetary transmissions, where very early in the design process an analytical solution to several inverse problems is required, making the proposed computerised symbolic modelling indispensable. Keywords: planetary transmission; symbolic modelling; dynamics; efficiency. Reference to this paper should be made as follows: Spitas, C., Amrin, A., Amani, A., Vasileiou, G. and Spitas, V. (2019) ‘Computerised symbolic planetary transmission modelling for automotive design’, Int. J. Powertrains, Vol. 8, No. 1, pp.58–73. Biographical notes: Christos Spitas is a Professor of Machine Design and leader of the Space Technology Research Group at Nazarbayev University. His field of expertise is smart structures and machine systems.