Controls Engineer, R&D

Fluidstack; San Francisco (CA); On-site; USD 210,000 - 260,000; Full time

Job summary

Fluidstack is seeking a hands-on controls engineer to own the machine and test-rig control architecture, implement interlocks, and enable production deployment with site BMS integration. The role emphasizes hardware-in-the-loop validation and fast iteration in a high-intensity R&D environment.

You will work with cutting-edge thermofluids systems and propulsion-like test controls, taking responsibility from design through to production readiness in a fast-growing AI infrastructure company.

Qualifications

• Wrote control logic for rotating machinery.
• Designed interlocks to prevent hardware damage.
• Carried out hardware-in-the-loop testing.
• Tuned control loops on live machinery.
• Delivered clear documentation for control systems.
• Familiar with industrial control platforms (Beckhoff, Siemens, Allen-Bradley, CODESYS).
• Experience with propulsion or vehicle test controls is a plus.

Responsibilities

• Own the control architecture for the machine and test rigs.
• Write safety interlocks and fault handling.
• Deliver capacity control via motor and turbine speed.
• Validate the control system with hardware-in-the-loop.
• Carry controls from test cell to production with site BMS integration.

Skills

Control logic

HIL testing

Loop tuning

Interlocks design

Documentation

Beckhoff

Siemens

Allen-Bradley

CODESYS

Propulsion control

Tools

Beckhoff

Siemens

Allen-Bradley

CODESYS

Job description

About Fluidstack

We exist to make humanity more free. For most of human history, you farmed or you starved. Technology gave people more time for the things they wanted to do, instead of things they had to do. Powerful AI will be the biggest lever for human choice we've ever built - but only if models are aligned with what humanity actually wants. There are groups building AI who don't share these goals. Whoever deploys frontier compute infrastructure fastest will decide whether AI expands human freedom or shrinks it.

We acquire power, design and build data centers, and operate them - with teams spanning hardware and software. Speed and scale are our key differentiators. We're singularly focused on delivering 10 to 100s of GWs of compute faster than anyone else, rethinking every layer of the stack. Come be a part of building civilization-scale infrastructure for AI.

We hire people who care deeply about this problem space. If that is you,

How We Operate

• Be a barrel. Full autonomy. Own things end to end, take on scope without being asked, no permission required to operate outside your core role.
• Insane urgency. We drive everything forward as fast as possible.
• Reason from first principles. Challenge every assumption. Zero analogy thinking, no egos, the best idea wins.
• Love of the game. The frontier of AI is the most interesting problem of our time. We put in long hours at high intensity to push the frontier forward.
• Build something that actually matters. If you're going to spend your time, spend it on something that matters to the world.

The Thermofluids R&D Team

Examples of key problems the team is working on

• Reject 10s of GW of heat, starting now. Fluidstack is targeting 10s of GW of compute over the next two years. Every watt of it becomes heat that has to go somewhere, and no cooling team has ever been asked to open at that scale rather than grow into it.
• Design and build the machines, because nobody can supply them. The merchant compressor market cannot deliver at this rate, and the vendor base behind today’s chillers will not scale to gigawatts. We are taking compressor and chiller design in house, working on machine architectures nobody sells today, and going from blank sheet to production faster than this industry thinks is possible.
• Own every thermofluids problem behind the fleet, not just the chiller. Working fluid and cycle architecture, heat exchangers at a scale that dominates the cost of the plant, two-phase heat transfer at the chip, and thermal energy storage. All of it is open, and whatever this team lands gets built thousands of times.

Role Scope

• Own the control architecture for the machine and the test rigs, spanning the compressor, the motor drive, the expansion turbine and the loop around them.
• Write the safety interlocks and fault handling for a machine whose working fluid can cross its critical point inside the normal operating range, taking the control problem with it.
• Deliver capacity control through motor and turbine speed rather than throttling valves, keeping the process fluid path free of valves at the design point.
• Validate the control system against hardware-in-the-loop before it ever touches the real machine, and prove the interlocks fire.
• Carry the controls out of the test cell and into the production chiller, including integration with site BMS and the wider plant.

What We're Looking For

The below is a starting point. We always make space for exceptional people, so if you don't fit this role exactly, tell us where you would

• You’ve written control logic for rotating machinery and you were in the room the first time it ran.
• You’ve designed interlocks where a fault means destroyed hardware or an injured person, and you can justify every one of them from first principles.
• You’ve run hardware-in-the-loop testing that caught something real before it reached commissioning.
• You’ve tuned loops on a live machine and worked out why the model and the plant disagreed.
• You’ve handed a control system to people who did not write it, with documentation they could actually use at three in the morning.
• Bonus: Propulsion or vehicle test controls (engine sequencing, abort and safing logic). Variable-speed drives and high-speed motor control (VFDs, magnetic bearing controllers). Refrigeration and chiller control (superheat, head pressure, capacity staging). Industrial control platforms (Beckhoff, Siemens, Allen-Bradley, CODESYS). Model-based development and HIL (Simulink, dSPACE, NI VeriStand).

We are committed to pay equity and transparency.

Fluidstack is an Equal Employment Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, national origin, sexual orientation, gender identity, disability and protected veterans’ status, or any other characteristic protected by law. Fluidstack will consider for employment qualified applicants with arrest and conviction records pursuant to applicable law.

Compensation Range: $210K - $260K