Sr. Mechatronics Engineer - Actuation & Drivetrain

9 Mothers • Austin, TX

12d • $150,000 - $200,000 • Onsite

About The Position

9 Mothers develops AI-powered machines designed to intercept and neutralize Group 1/sUAS threats in real time. Its flagship product, EDDA, is a low-power counter-drone system designed for use on vehicles, at bases, or in a soldier’s pack. The company emphasizes field-ready capability and rapid development.

The Senior Mechatronics Engineer will own the product’s motion-producing hardware, including motors, actuators, gearboxes, solenoids, motor drives, suppliers, test data, and tuning. The role covers the complete process from torque and inertia calculations, component and supplier selection, drivetrain design, characterization, and control-loop tuning through abuse testing and production release. The engineer will work across mechanical, electrical, firmware, and robotics teams to deliver reliable, high-performance actuation for demanding field environments.

Requirements

• 10+ years of experience in mechatronics or motion-system engineering and a track record of shipping servo-driven products; ideally pan-tilt units, gimbals, turrets, robotic joints, or vehicle-mounted systems.
• Hands-on selection, commissioning, and tuning of BLDC/PMSM servo systems, including field-oriented control, current/velocity/position loops, encoder and resolver feedback, drive configuration, and diagnosing instability, resonance, and thermal limits.
• Working knowledge of planetary, strain-wave, cycloidal, and worm drives, including ratio selection, efficiency, backlash, torsional stiffness, lubrication, and lifetime, and judgment about when direct drive is preferable.
• Experience building test rigs and conducting dynamometer, thermal, efficiency, and endurance tests.
• Comfort using oscilloscopes, current probes, DAQ, and Python or MATLAB to extract plant parameters from test data.
• Ability to design and detail a mechanical drivetrain from rotor to load, including bearings, shafts, couplings, seals, and preload, using CAD such as SolidWorks or similar and tolerance analysis.
• Programming ability in C/C++ or Python to configure drives, automate tests, and prototype control code; comfortable reading motor-control firmware.
• Experience specifying custom motors or gearboxes with vendors and managing qualification, second-sourcing, and cost-down.
• Hands-on approach to building, testing, measuring, troubleshooting, and repairing hardware.
• U.S. citizenship and ability to pass a background check.

Nice To Haves

• Harsh-environment qualification experience, including MIL-STD-810 shock and vibration, IP-rated sealing, EMI/EMC, and thermal cycling.
• Experience with weapon-mounted, recoil-loaded, or vehicle-mounted motion systems.
• Custom motor design experience with frameless, outer-rotor, or slotless motors and magnetics, and electromagnetic FEA tools such as Ansys Maxwell, JMAG, or FEMM.
• Solenoid and voice-coil design experience, including force-stroke-thermal trade-offs, PWM hold, and fast actuation.
• Structural dynamics experience, including modal analysis, designing control around structural modes, and stabilization on a moving platform.
• Advanced control experience, such as model-predictive, adaptive, or disturbance-observer control.
• Experience with CAN, EtherCAT, or ROS 2/DDS and drives such as ODrive, moteus, Elmo, Copley, or Kollmorgen.
• Production experience with DFM, incoming inspection, and actuator acceptance-test procedures.
• Security clearance or ability to obtain one.
• Personal experience building robots, racing drones, or rebuilding machinery.

Responsibilities

• Translate slew-rate, acceleration, pointing-accuracy, and duty-cycle requirements into torque, speed, reflected-inertia, and thermal budgets; select or specify motors, gear ratios, and drives with appropriate margins.
• Design and own the mechanical drivetrain from rotor to load, including gear stages, couplings, shafts, bearings, preload, lubrication, seals, stiffness, and backlash.
• Build characterization rigs and test motors and actuators for torque constant, back-EMF, inductance, cogging, torque ripple, friction, stiction, efficiency, thermal rise, backlash, and lost motion.
• Commission and tune current, velocity, and position control loops, including PID, feedforward, notch filters, and observers, for high-bandwidth tracking while avoiding structural resonance and overheating.
• Design and qualify actuation systems for shock, vibration, dust, mud, water, salt, EMI, and temperature extremes; perform failure analysis on returned hardware and drive corrective revisions.
• Qualify vendors; write motor, gearbox, and solenoid specifications; manage second sources and lead times; and drive production cost reductions.
• Serve as the technical interface among mechanical, electrical, firmware, and robotics teams on motion-related systems, and diagnose issues at the hardware-software boundary.
• Document derating curves, tuning procedures, acceptance tests, and drawings for production and field teams.
• Select and manage motors and actuators for EDDA’s azimuth, elevation, and auxiliary mechanisms, including BLDC/PMSM and frameless torque motors, steppers, and linear actuators.
• Select and assess gearbox and drivetrain options, including planetary, strain-wave, cycloidal, worm, and belt stages, and make direct-drive-versus-geared decisions.
• Specify or select motor drives and feedback systems, including commutation, encoders, resolvers, and Hall sensors.
• Characterize components through dynamometer and bench testing, including thermal derating, endurance, abuse testing, and production acceptance testing.

Benefits

• Meaningful early equity.
• Direct influence on the product roadmap and technology trajectory.
• Mission-critical work countering real-world threats.
• Brand-new lab optimized for rapid prototyping, equipped with NVIDIA Jetsons, high-end scopes, and 3-D printers.
• Employer pays 100% of the employee’s medical, dental, and vision insurance premiums and 50% of healthcare premiums for dependents.
• Unlimited PTO.
• Autonomy to make technical decisions and direct access to the founders.
• Onsite Austin team and collaboration culture.
• Relocation assistance.

What This Job Offers

• Job Type: Full-time
• Career Level: Senior
• Education Level: No Education Listed