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.