Between which two points?
A latency figure needs a start and an end. Ours starts when the game's telemetry reaches the platform and ends when the actuator moves. Ask every vendor for both points, and compare only figures that share them.
Compare · Method
The specs that decide
fidelity are the ones
almost nobody publishes.
Every motion platform datasheet gives you envelope and payload. Almost none give you transport delay with its measurement boundary, frequency response under load, or what the control-loop number actually refers to. This page is the table we wanted to find and could not: what a comparison of low-latency 6DOF motion systems needs, applied to our own row first.
The method
A number without a
measurement boundary
is not a specification.
"Sub-30 ms end-to-end" and "8 ms" are not comparable unless you know what each was measured between, under what payload, with what software in the chain. So every row below carries a label — VENDOR for a published manufacturer figure, ARK for one of ours, and "not published" where nobody states it at all.
Our own row first
Held to the standard we are asking for.
It would be cheap to demand disclosure from other manufacturers and not give our own. So this is our row for the Portal Development Kit (PDK).
Development Kit: early-access hardware, software in active development.
| Specification | Figure | Basis |
|---|---|---|
| Encoder resolution | 21-bit absolute, 2,097,152 positions per revolution | Published, arithmetic checkable |
| Drive loop, per motor | 8 kHz / 125 µs | ARK — read from the drive firmware timer |
| Control loop | 3.3 kHz, inverse kinematics included | ARK |
| Drive commands | 2.5 kHz or more per drive over CAN at 2 Mbaud, 3.3 kHz preferred | ARK |
| Game to motion | 1 kHz | ARK — a new pose every millisecond; the platform answers in under 1 ms |
| Transport delay | Under 1 ms — game telemetry in, motion out | ARK — boundary stated, which is the point |
| Frequency response under load | 629 Hz, measured, with up to 250 kg on board · each motor reproduces up to 2,000 Hz | Measured on the rig, payload stated |
| Motion envelope | Single-axis limits, all six axes | On the technology page, from the T1 firmware boot banner. |
How we know this
- 8 kHz drive loop, from the firmware timer configuration ARK drive firmware source
- 629 Hz measured on the rig with up to 250 kg on board; up to 2,000 Hz reproducible per motor ARK engineering record, 26 September 2026 · payload boundary stated 27 September 2026
- 3.3 kHz control loop; drive commands at 2.5 kHz or more per drive, 3.3 kHz preferred, with per-command encoder return; 1 kHz game to motion ARK engineering record
- Under 1 ms is the game-to-motion figure, from the game's telemetry reaching the platform to the actuator moving; game to motion runs at 1 kHz ARK rate definitions · /technology/latency/
What to ask any vendor
Four questions, including of us.
These are the questions that separate a specification from a headline.
Under what payload?
Frequency response and acceleration figures measured on an unloaded platform tell you very little about the platform with a person and a cockpit on it.
What does the loop rate refer to?
A command cadence, a servo loop and a cueing-engine tick are all quoted as "control rate". Ask which one, and what the others are.
Is there a published method?
A number with a test method and a report behind it is a specification. A number on its own is a claim.
Keep reading
Latency
Our own transport-delay account, in full.
Academic research
A protocol any lab can run to measure our latency independently.
The engineering
Ten pages, one subject each.
Every build starts with this platform. The PDK + ARK Ecosystem development kit finishes it: racing chassis, wheelbase, wheel, load-cell pedals and button box. Development-kit price for qualified recipients: $8,499.99.
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