Sr. Mechatronics Engineer - Actuation & Drivetrain

The posting, as 9 Mothers wrote it

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 th

[…]
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)