# Teardown of Zmotor humanoid robot linear actuator: stator, rotor, and inverted planetary roller screw in a 32 mm body

- Source: Reddit r/robotics
- Published: 2026-10-27T16:43:07.000Z
- RoboHot: https://robohot.news/en/items/d9f5f0m9ul7df8rmc8uwofzll
- Original: https://www.reddit.com/r/robotics/comments/1xgxn9f/teardown_of_a_humanoid_robot_linear_actuator/

## Summary

Someone tore down a linear actuator that Zmotor built for humanoid robots in the Chinese market, integrating a stator, rotor, and inverted planetary roller screw (IPRS) within a 32 mm body. The teardown author is seeking opinions on whether humanoid robot joints should use IPRS or ball screws.