Senior Actuation Engineer (Humanoid Joints)

At Mentee Robotics, we are redefining humanoid automation with an AI-first approach - combining perception, reasoning, and dexterous manipulation into fully autonomous systems that continuously learn and adapt.   We are now expanding with a new robotics Engineering Center in China, working hand-in-hand with our engineering teams in headquarters. Its mission: to rapidly develop our next-generation full-size humanoid and bring it to life - a walking, working platform that becomes the foundation of our next generation of products. This is a small, senior, hands-on team where speed of iteration is the core value.   We are looking for two Senior Actuation Engineers to design the joints of our humanoid - the single hardest hardware problem on the robot. You will own actuator modules end to end: motor selection, gear reduction, thermal design, sensing integration, and packaging - and you will cover the surrounding mechanical design (limbs, structure) as a secondary duty. Who you are • An actuator specialist first, a general mechanical engineer second • A first-principles thinker who questions assumptions and iterates fast • Hands-on in the lab: you build, instrument, and break your own designs • Comfortable with ambiguity and rapidly changing requirements Responsibilities岗位职责 • Design high torque-density actuator modules for legs, waist, and arms: quasi-direct-drive architectures with planetary reduction - motor selection/specification, gear design, bearings, sealing, and packaging • Own the torque, speed, thermal, and mass budgets per joint, aligned with the system DOF and mass targets • Drive quasi-direct-drive vs. high-reduction trade-offs together with the motion control team • Integrate sensing into the joint: encoders, temperature, and torque estimation provisions • Design the surrounding structure - limbs, torso frame, brackets - optimized for fast fabrication (machined plates, printed parts) • Own designs from concept through fabrication: CAD, tolerance analysis, DFM for prototype quantities, and supplier follow-up • Run joint-level dyno and life testing with the V&V engineer; iterate based on data • Work daily with electrical and embedded teams on the motor controller integration Requirements任职要求 • B.Sc. or M.Sc. in Mechanical Engineering or Mechatronics • 8+ years designing electromechanical actuation systems: BLDC motors with planetary reduction, ideally in quasi-direct-drive (QDD) configurations • Deep understanding of motor physics: torque constants, saturation, thermal limits, and their impact on transmission choice • Strong CAD skills (SolidWorks/NX/Creo) and proven concept-to-hardware track record • Experience with structural design, materials selection, and prototype fabrication methods • Hands-on lab and test experience with rotating machinery Advantages加分项 • Experience designing humanoid or quadruped joint modules • Experience with gear design and gear suppliers or custom motor winding specification • Deep experience with proprioceptive actuation and back drivability optimization • Thermal simulation and FEA experience • Comfortable communicating technical topics in English with international teams