Efficiency Estimation and Optimization of Multistage Compound Planetary Gearboxes and Application to the Design of the Active Skin Propulsion of EELS

This paper outlines a novel versatile geometric method for the estimation of the efficiency of multistage compound planetary gearboxes. The approach is based on a virtual pitch point modeling that allows for accurate representation of the gear interaction with forces applied at the pitch point. When this modeling is applied to all gears in a multistage compound planetary gearbox, the gearbox efficiency may be estimated directly from the free body diagram of the compound planets in a simple and easy to implement fashion. The gear design parameters that determine the gearing efficiency are identified and a consistent strategy for maximizing the efficiency of such gearboxes is outlined. Finally, the introduced methods are applied to the design of a three-stage compound planetary gearbox used in a novel snake-like robot.