# Sr. Mechatronics Engineer - Actuation & Drivetrain at 9 Mothers Sr. Mechatronics Engineer - Actuation & Drivetrain at 9 Mothers in Austin. On-site, full-time, paying $150k–$200k. Posted October 28, 2026. - Company: 9 Mothers - Location: Austin - Workplace: On-site - Job type: Full-time - Pay: $150k–$200k - Experience: 10+ years - Posted: 2026-10-28 - Apply: https://jobs.ashbyhq.com/9-mothers/1ea85050-cd71-422e-9ac5-f7d6adf0e4da/application - Source: https://jobmagic.ai/jobs/sr-mechatronics-engineer-actuation-drivetrain-9-mothers-9beycm ## Requirements - Experience: 10+ years in mechatronics or motion-system engineering with a track record of shipping servo-driven products — ideally pan-tilt units, gimbals, turrets, robotic joints or vehicle-mounted systems. ## Description **Location**: Onsite — Austin, TX **Employment Type**: Direct Hire, Full‑Time **Job Title**: Senior Mechatronics Engineer - Actuation & Drivetrain **About 9 Mothers** The modern battlefield has changed. Cheap, autonomous suicide drones have turned the tactical advantage upside down, and the world is looking for a solution. At 9 Mothers, we aren’t just "innovating"—we are building the shield. Backed by top-tier investors, we develop AI powered machines designed to intercept and neutralize Group 1/sUAS threats in real-time. Our flagship product is a low-power, counter-drone system built for the edge—on vehicles, at bases, or in a soldier's pack. **Why 9 Mothers?** While others build for "awareness" or "long-term research," we build for the immediate survival of those in harm’s way. We are a team of hackers, engineers, and mission-driven builders who value field-ready capability over polished slide decks. If you want to see your code or hardware in the field next month—not next year—this is your playground. **Position Summary** EDDA is only as good as its actuators, and we're hiring the person who owns them. You will be our servo wizard: the single owner of every motor, actuator, gearbox and solenoid in the product, from the first torque and inertia calculation through supplier selection, bench characterization, control-loop tuning, abuse testing and production release. You are as fluent in gearbox design — backlash, torsional stiffness, efficiency, lubrication, lifetime — as you are inside the current loop of the servo driving it. And you have lived with motion systems that get rained on, dropped, fired next to and bounced across a field on the back of a truck. **What You'll Own** Everything in the product that converts electrons into motion is yours — the parts, the suppliers, the test data and the tuning. - **Motors and actuators:** BLDC/PMSM and frameless torque motors, steppers where they earn their place, linear actuators — every axis that moves EDDA's azimuth, elevation and auxiliary mechanisms. - **Gearboxes and drivetrain:** planetary, strain-wave (harmonic), cycloidal, worm and belt stages; the direct-drive-versus-geared call on each axis; bearing arrangements, preload, backlash and the stiffness budget that sets achievable control bandwidth. - **Solenoids and discrete actuators:** latches, safeties, indexing and release mechanisms — the fast, simple actuators that must work every time, in the cold, after being dropped. - **Motor drives and tuning:** drive selection or specification, commutation and feedback (encoders, resolvers, Hall sensors), current/velocity/position loop tuning, feedforward and filtering. - **Characterization and test:** dynamometer and bench rigs, thermal derating, torque ripple and cogging, efficiency maps, endurance and abuse testing, and the acceptance tests production runs on every unit. - **The actuation supply chain:** vendor qualification, custom motor and gearbox specifications, second sources, cost-down and the lead times that production depends on. **Essential Duties** - **Size and select:** turn slew-rate, acceleration, pointing-accuracy and duty-cycle requirements into torque, speed, reflected-inertia and thermal budgets; pick or specify the motor, gear ratio and drive that meet them with margin — and show the math. - **Design the drivetrain:** own the mechanical path from rotor to load — gear stages, couplings, shafts, bearings, preload, lubrication and seals — and the stiffness and backlash budget that determines how hard the loops can be pushed. - **Characterize everything:** build the rigs and run the tests — torque constant, back-EMF, inductance, cogging and ripple, friction and stiction, efficiency, thermal rise, backlash and lost motion — so tuning starts from a measured plant, not a datasheet. - **Tune the loops:** commission and tune current, velocity and position loops (PID, feedforward, notch filters, observers) for aggressive high-bandwidth tracking without exciting structural modes or cooking the motor. - **Engineer for abuse:** design and qualify actuation for shock and vibration from vehicle mounts and weapon firing, dust, mud, water, salt, EMI and temperature extremes; lead failure analysis when hardware comes back from the range broken, and make sure the next revision doesn't. - **Own the supply chain:** qualify vendors, write motor, gearbox and solenoid specifications, manage second sources and lead times, and drive cost-down for production volumes. - **Bridge the teams:** be the technical interface between mechanical, electrical, firmware and robotics on anything that moves; triage failures at the hardware-software boundary and call whether a problem is mechanical, electrical or control. - **Document and release:** derating curves, tuning procedures, acceptance tests and drawings that production and field teams can execute without you in the room. **Requirements** - **Experience:** 10+ years in mechatronics or motion-system engineering with a track record of shipping servo-driven products — ideally pan-tilt units, gimbals, turrets, robotic joints or vehicle-mounted systems. - **Servo depth:** hands-on selection, commissioning and tuning of BLDC/PMSM servo systems: field-oriented control, current/velocity/position loops, encoder and resolver feedback, drive configuration, and diagnosing instability, resonance and thermal limits on the bench. - **Gearbox fluency:** working command of planetary, strain-wave, cycloidal and worm drives — ratio selection, efficiency, backlash, torsional stiffness, lubrication and lifetime — and a clear sense of when direct drive beats gearing. - **Actuator characterization:** you have built test rigs and run dynamometer, thermal, efficiency and endurance tests; comfortable with scopes, current probes, DAQ and Python or MATLAB to extract plant parameters from data. - **Drivetrain design:** can design and detail the mechanical path from rotor to load — bearings, shafts, couplings, seals, preload — in CAD (SolidWorks or similar) with tolerance analysis. - **Programming:** enough C/C++ or Python to configure drives, automate tests and prototype control code; comfortable reading motor-control firmware. - **Supplier management:** have specified custom motors or gearboxes with vendors and run qualification, second-sourcing and cost-down. - **Hands-on rigor:** you build, break, measure and fix your own hardware. - **Compliance:** U.S. citizenship and the ability to pass a background check. **Nice‑to‑Have** - **Harsh-environment qualification:** MIL-STD-810 shock and vibration, IP-rated sealing, EMI/EMC, thermal cycling — and the scars from hardware that was abused in the field anyway. - **Weapon-mounted, recoil-loaded or vehicle-mounted motion systems.** - **Custom motor design:** frameless, outer-rotor or slotless motors and magnetics; electromagnetic FEA (Ansys Maxwell, JMAG, FEMM). - **Solenoid and voice-coil design:** force-stroke-thermal trade-offs, PWM hold, fast actuation. - **Structural dynamics:** modal analysis and designing control around structural modes; stabilization on a moving platform. - **Advanced control:** model-predictive, adaptive or disturbance-observer control. - **Drive ecosystems:** CAN, EtherCAT, ROS 2/DDS; hands-on time with ODrive, moteus, Elmo, Copley, Kollmorgen or similar drives. - **Production experience:** DFM, incoming inspection and acceptance-test procedures for actuators. - Security clearance or the ability to obtain one. - You build robots, race drones or rebuild machinery on your own time. **Benefits** - **Meaningful Early Equity:** You aren't just an employee; you are a foundational owner. Your contributions directly drive the value of your stake in the company. - **Direct Roadmap Influence:** Forget the bureaucracy of big defense. You will have a seat at the table, directly shaping our product and technology trajectory from day one. - **Mission-Critical Work:** We don't build for "what if." We build systems the Department of War actively needs to counter immediate, real-world threats. - **The Builder's Playground:** Work in a brand-new lab fully optimized for rapid prototyping, equipped with NVIDIA Jetsons, high-end scopes, and 3-D printers. - **100% Employer-Paid Premiums:** We cover 100% of your medical, dental, and vision insurance premiums and cover 50% of healthcare premiums for your dependents. - **Unlimited PTO:** We value results, not clock-watching. Take the time you need to stay sharp and recharge. - **Zero Red Tape:** You report to the founders. You have the autonomy to make technical decisions that would take months of committee approval at a larger firm. - **Austin-Based Culture:** Join an onsite team in Austin, TX, where we prioritize high-bandwidth collaboration and rapid field-testing. - **Relocation Assistance:** We want the best talent in the room. If you aren't in Austin yet, we’ll help you get here, to make your transition to the Silicon Hills seamless. **About the Interview** - Virtual interview (45 min via MS Teams) - Onsite interview in Austin (1.5 hr in-person)