Motion cueing
What the 20 kHz washout stage is actually doing to the signal, and why a platform cannot simply replay the game.
Low-latency 6DOF Under 1 ms — game
to motion.
Every motion platform quotes a latency and almost none say what it was measured between, so a low-latency 6DOF claim tells you little on its own. Ours, on the Portal Development Kit (PDK), is measured at under 1 millisecond, from the game's telemetry reaching the platform to the actuator beginning to move. The boundary is the important half of that sentence: ask any vendor where their clock starts and where it stops.
The figure
Under 1 ms.
Game telemetry in,
motion out.
That is the number, and that is the boundary. The clock starts when the game's telemetry reaches the platform and stops when the actuator begins to move, and the time between them is under a millisecond. Game to motion runs at 1 kHz, and the motor is moving before the next command lands.
The chain
Where the millisecond goes.
Five rates run inside the platform between the game and the leg.
The filter that decides what you are given and what is returned below perception, smooth rather than stepped between telemetry frames.
A new pose for the platform every millisecond.
Each pose solved into six leg positions.
A new target for each drive, 3.3 kHz preferred.
Each motor closes its own loop on a fresh 21-bit absolute encoder reading every 125 µs.
Yardsticks
Under 1 ms, beside the numbers others publish.
Each figure is its publisher's own, with the two points its clock runs between, where the publisher states them.
| Platform or rule | Latency | Measured between | Source |
|---|---|---|---|
| ARK PDK | under 1 ms | Input to motion: the input reaching the platform, and the motor starting to turn | ARK |
| Qubic System QS-S25 | under 8 ms | “Telemetry input to actual physical motion” | Qubic System's product page, September 2026 |
| FAA limit for a certified helicopter flight training device's motion system | 150 ms | The pilot's control input, and the reaction of the motion, instruments and visuals | 14 CFR Part 60 |
Why it matters
Under 1 ms.
Back to centre, unfelt.
Every rig has to come back to centre before the next move, and the further it goes, the longer the trip back. Measured: under 1 ms game telemetry to motion. What a rider feels is not something ARK can guarantee.
Delay costs presence. In a study presented at IEEE Virtual Reality in 2003, people in a virtual scene with about 50 ms of end-to-end delay reported a stronger sense of being there, and showed a larger change in heart rate, than people at about 90 ms (Meehan, Razzaque, Whitton and Brooks).
Questions
What people ask about latency.
What is the PDK's latency?
Under 1 millisecond, measured from the game's telemetry reaching the platform to the actuator beginning to move. Game to motion runs at 1 kHz, and the actuator is moving before the next command lands.
What does latency mean on a motion platform spec sheet?
On its own, very little. A number without a measurement boundary is not a specification: the same machine can report very different figures depending on where the clock starts and where it stops. So the thing to ask of any latency figure is what it was measured between.
How does under 1 ms compare with other motion platforms?
Qubic System publishes under 8 ms for its QS-S25, from “telemetry input to actual physical motion”. The FAA lets the motion system of a certified helicopter flight training device lag up to 150 ms behind the pilot's control input. The PDK goes from input to motion in under 1 ms, counted from the input reaching the platform.
Keep reading
Closed-loop control
What the loop closes on, and how often — the rates this figure comes from.
Field-oriented control
The 8 kHz loop at the end of the path, and what it closes on.
Every development kit starts with this platform. The PDK + ARK Ecosystem development kit finishes it — racing chassis, wheelbase, wheel, load-cell pedals and button box, $8,499.99 (development-kit price).
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Built in sequence for qualified recipients: ready to ship an estimated 3–6 months from order confirmation; delays of up to 12 months are possible