Oct 14, 2026
In humanoid robotics, planetary gear systems are commonly used in actuators to achieve high reduction ratios within a very compact design envelope. The number of gear teeth and planets determines the phasing configuration of the planetary gear set, which directly influences load distribution and excitation behavior.
In an in-phase configuration, all planet meshes engage with the same meshing phase. This generally promotes uniform load distribution and a lower mesh load factor. However, because the mesh stiffnesses of all planets vary simultaneously, this configuration will probably result in the highest carrier transmission error.
With sequential phasing, the meshing phases are evenly distributed among the planets. As a result, planets in a high mesh stiffness state can compensate for those experiencing lower stiffnesses, helping to reduce carrier transmission error.
In a counter-phase configuration, opposite planets share the same meshing phase. This arrangement can cause the resulting forces acting on the carrier to largely cancel each other, thereby reducing carrier force excitation.
Mixed-phase configurations occur with unequal planet spacing and require more detailed analysis to fully assess their dynamic behavior.
KISSsoft Loaded Tooth Contact Analysis (LTCA) enables these effects to be evaluated in detail, including carrier transmission error, individual planet transmission errors, and load distribution among the planets. This allows engineers to quantify the influence of planetary phasing on transmission behavior and optimize the gear system for the specific actuator requirements.