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Striker-125 · Rev D.2
Robot Zero
The league's own Striker-class machine: a 1250 mm twin-track humanoid with two direct-drive arms, a three-axis waist and armour designed to come off in pieces. In build now.
Engineering Status
Every figure on this page is from the Rev D.2 controlled design baseline. They are design targets under staged validation, not measured results from a finished machine — and we would rather publish them honestly labelled than round them into marketing. Numbers move as CAD mass properties, bench testing and instrumented contact tests come in; this page moves with them.
The Concept
A Fast Humanoid
on a Tracked Base
Bipedal walking is a research programme. Fighting is not. Robot Zero puts everything into the half of the machine an audience actually watches.
A compact twin-track base carries a fast humanoid upper body. The visual legs are structural towers that also house the batteries — the biggest centre-of-gravity lever available. Above them sits a three-axis waist and two four-degree-of-freedom arms, all direct drive, no belts anywhere in the striking path.
Look fast. Survive an exchange.
Get back up.
Those three objectives set every number below. The rest is consequence.
Deliberately Excluded
- No bipedal walking, no balance control
- No powered knee or ankle
- No dexterous hands
- No autonomous striking — a human drives every punch
- No exposed metal striking surface
- No critical electronics in the head
Each exclusion buys mass, cost and schedule back for the parts that show up on camera. A machine that walks badly is worse television than one that drives well.
Strike Envelope
Three Punches
A 0.90 kg fist on a 5.50 kg arm. Fist speed is the spectacle target; energy falls out of it. A jab–cross–hook combination completes in 0.55 seconds.
| Strike | Fist speed | Effective mass | Energy | Impulse | Extension | Retraction | Cycle |
|---|---|---|---|---|---|---|---|
| Jab | 8.5 m/s | 1.20 kg | 44 J | 10.2 kg·m/s | 70 ms | 70 ms | 140 ms |
| Cross | 11.0 m/s | 1.46 kg | 89 J | 16.1 kg·m/s | 95 ms | 80 ms | 175 ms |
| Hook | 12.0 m/s | 1.60 kg | 115 J | 19.2 kg·m/s | 140 ms | 90 ms | 230 ms |
Why These Energies
They were not chosen for their own sake. 0.90 kg is the lightest fist that can still carry a load-spreading backplate, a compliant element, a load cell and a bayonet interface. The fist mass set the energy — and the energy landed at two to five times the armour panel fracture threshold, which is the ratio that gives visible damage per hit without a one-shot kill.
Retraction Sells It
The return stroke runs at a higher jerk limit than the extension. It costs nothing in software and roughly doubles apparent hand speed. A spectator cannot see joules; they see hand speed, retraction snap, body rock and panels coming off.
Nothing Rigid Lands
A 15 mm polyurethane compliant element behind a replaceable outer face stretches the contact from roughly 6 ms to 25 ms, cutting peak force by about four times for the same impulse. There is no exposed metal striking surface anywhere on the machine.
Platform
The Numbers
Dimensions & Mass
Mobility & Power
Kinematics
Thirteen Powered
Degrees of Freedom
Two drive, three waist, eight arm. Every arm joint is direct drive — deleting the shoulder and elbow belt stages removed four belts, four tensioners, belt-wear inspection from the pre-round checklist, and belt slip as a failure mode.
| Joint | Count | Range | Peak speed | Drive |
|---|---|---|---|---|
| Shoulder flexion | 2 | −45° to +170° | 11 rad/s | Direct, torso-mounted cartridge |
| Shoulder abduction | 2 | −10° to +100° | 7 rad/s | Direct, torso-mounted cartridge |
| Humeral rotation | 2 | ±120° | 15 rad/s | Direct, upper arm |
| Elbow flexion | 2 | 0° to 155° | 13.5 rad/s | Direct, at the elbow |
| Waist yaw | 1 | ±75° commanded | 10 rad/s | Direct, pelvis yaw ring |
| Waist roll | 1 | ±18° commanded | 2.1 rad/s | Direct, middle gimbal cradle |
| Waist pitch | 1 | −15° to +30° | 2.5 rad/s | Direct, upper gimbal trunnion |
| Track drive | 2 | Continuous | — | Geared, in-pod |
Why Four Arm DOF
Humeral rotation is the non-negotiable one. Without it every punch lies in a single plane and the machine reads as a windscreen wiper. Four gives you jab, cross, hook, uppercut, overhand, high guard, low guard, cross-guard and shell.
Why a Three-Axis Waist
Yaw drives the hook. Pitch gives the body-rock that sells recoil. Roll is the dodge — a slip to the outside that lets a machine make a fight look like a fight rather than a shoving match.
Quick-Change Fists
A keyed three-lug bayonet with a captive shear pin. Five seconds, one person, no tools. All variants held within ±45 g of 0.90 kg, because the fist is three quarters of the jab's effective mass.
Damage
Armour That
Comes Off in Pieces
Twelve frangible zones — two chest, two shoulder cap, two upper arm, two forearm, two hip, one cowl, one spine — over a crush layer over sub-armour. Panels are tuned to fracture between 18 and 22 J, which puts a jab at roughly twice threshold and a hook at nearly six times.
First panels off. Zone LEDs switch from blue to red where they landed.
Clearly damaged. Structure visible through the gaps, mixed amber and red.
Heavily stripped. This is the part of the fight people clip and share.
Fully stripped bodywork — and still fighting at full capability.
Damage Is a Scoring System, Not a Failure Mode
A machine with every panel gone still drives, still punches, still guards. That is deliberate. Armour exists to make damage legible from the back row and on a phone screen, not to decide fights by attrition of function.
Panels release on nylon shear pins onto a short captive hinge with a secondary tether, so a shed panel cannot reach the tracks, the joint envelopes or the cameras. No panel removal ever exposes batteries, live conductors or pinch points.
Lit From Behind
A continuity loop and an addressable LED strip sit behind every zone. Intact panels glow cool blue through the gaps. A broken loop registers the hit and takes that zone amber, then red. A 60 ms white flash fires off the fist load cell on contact.
Service targets, because turnaround between fights is a real constraint: fist 5 s · panel and crush layer 15 s · complete arm 45 s · battery 20 s · track pod 3 min.
Knockdowns
Designed to
Go Down.
Designed to
Get Up.
An aligned simultaneous exchange — throwing a hook while taking a cross on the same side — screens as a knockdown. Earlier revisions treated that as a risk to engineer out. Rev D treats it as a designed-for event.
Engineering it away costs mass and stance width that are better spent elsewhere, and a knockdown a machine recovers from is the single most compelling thing a humanoid combat robot can do. So the requirement became: make it rare, survivable and recoverable.
A machine that goes down,
visibly struggles, rocks itself
up and returns to guard is
worth more than any punch
in the specification.
Five Layers of Recovery
- Anti-tip skids — toe and heel skids integrated into the track silhouette, engaging around 20° of lean, before the static tip threshold
- Fall-tolerant structure — impact-absorbing shoulder caps, cowl and spine hump over sub-armour, all replaceable
- FAULT_RETRACT — both arms pull to a protected pose on detected free-fall, before ground contact
- ARM_BRACE — the arm extends on the falling side, arresting the roll at 61° instead of flat. The difference is a factor of 3.6 in recovery energy
- ARM_PUMP — both arms swing through their full arc and the reaction rocks the body up. Target three to four cycles
The machine must not be able to come to rest beyond 65° in any orientation — a shell-geometry constraint verified in CAD and then physically, with deliberate controlled falls in every orientation. Self-right is operator-initiated rather than automatic, so a marshal can intervene first. After eight pump cycles the sequence aborts and signals for assistance.
Silhouette
It Has to Read
at Thirty Metres
Broad shoulders over a narrow waist — 620 mm over 265 mm. That ratio does most of the work before a single panel is painted.
- Neutral torso pitched 8° forward on the waist axis — a fighter's stance, not a service robot's
- No face. A small angular sensor cowl sits low between the shoulders
- Boots with heels — shin fenders continue the leg-tower line into the pod, and the rear anti-tip skid is styled as the heel
- Matte or satin only, pre-weathered, with asymmetric paint so orientation is instantly readable on camera
- Exposed shoulder cartridge and waist bearing ring — the mechanism is the aesthetic
- Cool blue underglow and panel-gap lighting; a distinct slow pulse while the machine is trying to get up
At 5.5 kg the arms can be built genuinely slim, and a slim arm on a 620 mm shoulder reads athletic where a heavier limb reads industrial. That is a real aesthetic gain out of a mass optimisation, which is usually how the good ones arrive.
Validation Ladder
No stage is skipped and nothing is accepted from a drawing. Analytical screening, then CAD mass properties, then simulation, then coupon tests, then subsystem, then integration — and a simulation that has not been correlated against hardware is never release evidence.
Follow the Build
Every Session
Is on Camera
Robot Zero is being filmed from bare frame to first fight — including the failures, which are the interesting part. Its lower body publishes free as the Striker Reference Chassis.