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.

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:

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:

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:

Experience designing humanoid or quadruped joint modules (e.g., at Unitree, Wuji, Fourier, AgiBot)

Experience with gear design and gear suppliers or custom motor winding specification

Deep experience with proprioceptive actuation and backdrivability optimization

Thermal simulation and FEA experience

Comfortable communicating technical topics in English with international teams

Senior Actuation Engineer (Humanoid Joints)