KINEMATIC ANALYSIS OF THE COMPLEX PLANETARY GEAR TRAIN OVERVIEW

Planetary gear trains represent a special type of gear transmission whose element motion resembles the movement of planets around the Sun. Thanks to their compact design and the ability to achieve high transmission ratios with a relatively low total mass, they have found application in various fields of mechanical engineering. The basic planetary gear train (PGT) consists of two central gears (one with external teeth and the other with internal teeth), planet gears, and a carrier on which the planets are mounted. By connecting the appropriate elements to the input and output shafts, as well as by fixing certain components, different configurations or planetary gear train schemes can be obtained. This is described in the literature [1] and [2]. By adding gears and carriers to the structure of a simple planetary gear train, complex planetary gear trains are formed. Their advantage over simple ones lies in achieving a greater number of different transmission ratios. This has defined the wide application of PGT in automatic transmissions of various passenger and heavy-duty vehicles, as well as buses and construction machinery. To determine the transmission ratios, or the speeds of a multi-stage planetary gear train, it is necessary to understand the kinematics of the coupling between its elements. Considering the complexity of the motion, this represents a very challenging task. In books [1, 2], the most commonly used methods for solving the kinematics of PGT are presented.