Lightweight design and verification of space harmonic drive

• A novel lightweight design method for harmonic drive has been proposed with a lightweight of 38 %. • This lightweight design approach reduces stress on the flexspline and improves the life of the reducer. • This lightweight design approach improves the stiffness and reduces backlash . As the key component of space mechanism, the lightweight design of harmonic drive can significantly reduce the inertia of mechanism and enhance the payload. It is of great significance to the development of space equipment. In this paper, a novel lightweight design method for harmonic drive has been proposed. The structure and gear tooth profile of the harmonic reducer is designed based on modified polyether ether ketone (PEEK). The meshing forces and stresses of the PEEK rigid wheel harmonic drive (PRWHD) are analyzed considering the effect of assembly preload force. The transmission efficiency model of PRWHD is developed for variable speed and load. The PRWHD is manufactured and the weight of the PRWHD is reduced by 38 %. The flexspline stress can be reduced by 68.67 % and the torsional stiffness of the reducer is increased by 40 %. The influence of the preload force on the transmission performance is more obvious at smaller loads. Compared to steel rigid wheel harmonic drive, the transmission efficiency of the PRWHD remains virtually unchanged. PRWHD has a higher number of meshed teeth, and it shows a significant advantage in terms of performance. PRWHD will have great potential to be used in space mechanisms in the future.