Sr. Mechatronics Engineer - Actuation & Drivetrain

The role

You will own all components that convert electrons into motion, including motors, actuators, gearboxes, and solenoids. You will handle everything from torque calculations and supplier selection to control-loop tuning and abuse testing.

What you will do

• Size and select motors, gear ratios, and drives based on requirements
• Design the mechanical drivetrain including gear stages, couplings, and bearings
• Build test rigs and run characterization tests like torque constant and efficiency
• Commission and tune current, velocity, and position loops
• Design and qualify actuation for shock, vibration, dust, mud, water, and temperature extremes
• Qualify vendors and manage the actuation supply chain
• Act as technical interface between mechanical, electrical, firmware, and robotics teams
• Document derating curves, tuning procedures, and acceptance tests

Required qualifications

• 10+ years in mechatronics or motion-system engineering
• Track record of shipping servo-driven products
• Hands-on selection, commissioning and tuning of BLDC/PMSM servo systems
• Working command of planetary, strain-wave, cycloidal and worm drives
• Ability to build test rigs and run dynamometer, thermal, efficiency and endurance tests
• Proficiency with scopes, current probes, DAQ and Python or MATLAB
• Design mechanical paths in CAD (SolidWorks or similar) with tolerance analysis
• Programming in C/C++ or Python to configure drives and automate tests
• Experience specifying custom motors or gearboxes with vendors
• U.S. citizenship
• Ability to pass a background check

Nice to have

• Harsh-environment qualification (MIL-STD-810, IP-rated, EMI/EMC, thermal cycling)
• Weapon-mounted, recoil-loaded or vehicle-mounted motion systems
• Custom motor design and electromagnetic FEA
• Solenoid and voice-coil design
• Structural dynamics and modal analysis
• Advanced control (model-predictive, adaptive or disturbance-observer)
• Experience with CAN, EtherCAT, ROS 2/DDS or specific drive ecosystems
• Production experience (DFM, incoming inspection, acceptance-test procedures)
• Security clearance or the ability to obtain one
• Building robots, racing drones or rebuilding machinery on own time

Benefits

• Meaningful Early Equity
• Direct Roadmap Influence
• Mission-Critical Work
• The Builder's Playground lab
• 100% Employer-Paid Premiums for medical, dental, and vision
• 50% coverage of healthcare premiums for dependents
• Unlimited PTO
• Zero Red Tape
• Relocation Assistance

Before you apply

• U.S. citizenship required
• Ability to pass a background check

About the company

9 Mothers develops AI powered machines designed to intercept and neutralize Group 1/sUAS threats in real-time. They build low-power, counter-drone systems for vehicles, bases, or soldiers' packs.