Development of the low backlash planetary gearbox for humanoid robots

Abstract

The low backlash planetary gearbox as a substitute for a harmonic drive in humanoid robotics, is presented in this paper. After analysis of the contemporary designs of the low backlash coaxial toothed gearboxes, a concept of planetary gearbox with taper gears has been chosen. A synthesis of a planetary mechanism which satisfies the prescribed kinematic-dynamic requirements as well as the design limitations has been performed. Based on the obtained results, parameters necessary for the gearbox design have been defined. The proposed solution has been analysed from various points of view. Analysis results show that the proposed solution has low backlash (<4 arcmin), high coefficient of efficiency (about 97%), four times higher load capacity and five times lower price in comparison with the currently available corresponding harmonic drives. Overall dimensions are nearly the same, while the mass of the planetary gearbox is 10% larger than mass of the corresponding harmonic drive.