A Generic Function for Automated Modeling and Feedforward Control of Planetary Gear Sets

Abstract

This paper introduces a generic function for automated modeling and feedforward control of planetary gears (PGs). Given the information on configuration, namely, the internal connection relationship between each PG, location of external torques, location and locking state of each clutch, this function outputs a ready-to-use kinetic model. The derived model can then be converted into numeric form by substituting the symbols in the matrix with real values and used for simulation, analysis or controller design. Since the output of the function is in symbolic form, it provides the theoretically most accurate results. Furthermore, compared to other kinds of automated modeling techniques for PG, the proposed function is: (a) more “straightforward” in a sense that it relies solely on direct matrix formulation and no other methods such as system identification are needed and therefore can be implemented in a single environment such as matlab; (b) more “generic” since it is capable of deriving both full-degrees-of-freedom (DOF) and reduced-DOF models for virtually any configuration regardless of the number, connection, and location of input/output shafts or clutches. By exchanging certain variables in the list of unknowns and knowns, the function can also be used to facilitate the design of feedforward controllers.