Hardware-in-the-Loop Testing
Hardware-in-the-loop testing runs real control hardware against a simulated plant, validating the twin and controllers before the machine exists.
Real controllers, simulated plant
Hardware-in-the-loop, HIL, testing connects real control and estimation hardware to a high-fidelity simulation of the plant that runs in real time. The controller cannot tell it is talking to a simulation rather than the real machine. This lets engineers exercise the actual control and twin software, on the actual hardware, against realistic and even dangerous scenarios, long before a physical plant is available.
Why it matters for a machine not yet built
For a plant under design, HIL is the closest thing to operating experience. It validates that the real-time twin meets its deadlines on real hardware, that control strategies behave, and that failure responses work, all without risking a machine that does not yet exist. It turns the design-phase simulation into a genuine test bed for the software that will one day run the plant.
The fidelity requirement
- The plant simulation must run in real time to interact with real hardware
- It must be faithful enough that the controller's behavior transfers to the real machine
- It must reproduce sensor characteristics, including noise and latency
- It must be able to inject faults and off-normal conditions on demand
The honesty boundary
HIL validates the control and estimation system against a model, not against reality. Its results are only as trustworthy as the plant model, and it cannot substitute for validation on the real machine. It reduces risk and matures the software; it does not prove the physics. Keeping that boundary clear prevents overclaiming.
In the Kronos program
HIL testing exercises the twin-in-the-loop control for both the Hyperion breeder and the burner against their high-fidelity plant models on representative real-time hardware. This is where timing, failure behavior, and control strategies are hardened ahead of construction, beginning in the second quarter of 2027, and ahead of first tritium for the first breeder near 2030. See twin-in-the-loop control and operator training simulators.