Autonomous · Port equipment

Straddle carrier

Picks a box off the ground, carries it anywhere, stacks it four high.

Phase 5 · 2031+Concept design
Moves / hour
40
one move every 90 s
Per lift
1 × 40 ft
Gross weight
≈ 72 t
Metal content
≈ 88%
I · Blueprint
Side elevation, live systems
3 high40 ft03060710.3 m overall length15.7 m overall height (1-over-3)0205080910Access ladder041213Motor cables (hidden)0111Hoist ropesSpreaderCarried box, 1-over-3Row stacked 3 high40 ft box under girder (hidden)SECTION A–A · LOOKING FORWARD4.87 m3.47 m clear15.7 mSensor podsTop cross girderLeg frameSill & wheel forkPLAN · ALL-WHEEL STEER10.3 m4.87 mSill beams, 4 wheels eachTurning radius 9.3 m outside · 3.6 m insideBattery · converters · hoist drumHub-motor wheelDETAIL B · IN-WHEEL HUB MOTOR, DIRECT DRIVESteering cylinderKing pin, steeredTyreRim, turns with rotorRotor & magnetsStator windingsAxle & bearings (fixed)Air gapDriven wheel, hub motor (4)Steered wheel, not drivenSteering cylinders & tie rods
01Hub motors, 4 × 130 kW on 4 of 8 wheels, all 8 steeredDrive
02Portal leg frames — 1-over-3 stackingStructure
03Top-lift spreader & 40 ft containerHandling
04Battery module, 533 kWh, 350 kW chargingPower
05Sensor pods — lidar, radar, visionStructure
06Hoist motor 250 kW, gearbox & rope drumsHandling
07Hoist ropes & girder sheavesHandling
08Top girder & machinery houseStructure
09Front-top sensor cabStructure
10Sill beams & wheel forksStructure
11Steering cylinders & tie rodsDrive
12Frequency convertersPower
13Automated charging inletPower
II · Power & drivetrain

Four hub motors, every wheel steered.

Four of the eight wheels carry their own hub motor and every wheel steers, so the carrier can steer in any direction and keep moving if one drive faults.

Battery, inverters and hub motors — rotating view
The battery and both inverters ride in the top frame with the hoist winch; the DC bus runs down the legs to four driven wheels that each carry a 130 kW direct-drive hub motor; all eight wheels steer independently. The ropes pay out from the winch to the headblock between the legs.
01Battery pack — 533 kWh, 16 modules, liquid-cooled
02Traction inverters — 2, one per pair of wheels
03Charger & DC-DC — 350 kW port on the frame
04Hoist winch — 250 kW motor and drum, 24 m/min at 40 t
05Ropes & headblock — 60 t, 1 × 40 ft
06Legs — DC bus and steering actuators inside
07Hub-motor wheels — 4 × 130 kW direct drive, 24 km/h
08Wheel steering — all 8 wheels to ±90°
Driven wheel & hub motor
Wheels8, 4 driven, all steered to ±90°
Hub motors4 × 130 kW, direct drive, outer rotor
TyreØ 1.33 m, 96 rpm at 24 km/h
Torque12.9 kN·m per driven wheel
Regeneration75–80% of braking energy to the DC bus
Naked drivetrain — energy to motion
III · How it is put together

Built in blocks, joined, then brought to life.

Blocks are fabricated in parallel, joined in sequence, and the power module and autonomy core go in last. The loop below replays the build order.

POWER MODULE
I
Structural members fabricated
II
Frame erected & aligned
III
Drive & power package installed
IV
Sensors & autonomy calibrated
V
Commissioned on the terminal
IV · Specification

Concept specification.

Design specification for the autonomous straddle carrier.

Stacking
1-over-3
Safe working load
60 t
Containers per lift
1 × 40 ft
Moves per hour
40 · one move every 90 s
Gross weight
≈ 72 t
Metal content
≈ 88% steel
Battery
533 kWh · 6.5 hr per charge
Consumption
≈ 70 kWh / hr at 40 moves / hr
Top speed
24 km / h
Traction
4 × 130 kW direct-drive hub motors
Steering
All 8 wheels, ±90°
Hoist drive
1 × 250 kW
Hoist speed
24 m/min at 40 t · 18 at 60 t · 48 empty
Charging
350 kW, 90 min to full
Installed power
≈ 0.8 MW
Crew
0 · no cab
Onboard compute
Two AI modules: the carrier drives among people; a certified controller holds the safe envelope
Modules2 AI modules (spreader and box landing; travel path and people) + 1 certified safety controller
CPU32 cores (2 × 16) + 4 lockstep real-time cores per module
AI throughput10,000 TOPS total (2 × 5,000, INT8 / FP4 sparse)
Memory2 × 128 GB LPDDR6, 600 GB/s per module
Power draw200 W compute; ≈ 0.4 kW with 12 cameras, 4 lidars and 4 radars — 0.6% of the carrier’s ≈ 70 kW average draw
Process node2 nm-class SoC; safety controller on a mature 16 nm node, 15-year supply. Compute is a line-replaceable unit, swapped at mid-life of the carrier’s 20 years
RedundancyEvery sensor is wired to both modules. Module 1 is primary for the spreader and box landing and hot standby for the travel path; module 2 is primary for the travel path and people and hot standby for the spreader. Module 2 runs a different people-and-obstacle model, so the two paths never share a blind spot. Either one alone runs the carrier at reduced speed.
SafetyThe SIL 3 controller has its own sensors: encoders on every wheel and wheel angle, hoist encoders and load cells, limit switches on the hoist and spreader, and safety-rated lidar and radar at all four corners. A software fault can never drive the carrier outside its certified safe envelope.
Sensors12 cameras on automotive Ethernet through camera aggregation switches, 4 lidars at the corners, 4 radars, box-edge cameras on the spreader, wheel-angle and hoist encoders
LinkPrivate 5G; every move assigned by The Brain, position reported at 10 Hz; braking decided aboard in ≤ 100 ms; drive current loops closed every 1 ms
A straddle carrier is 15.7 m tall, moves at 24 km/h and works where trucks and people are. Both modules see every sensor; each runs its own zone and holds the other’s state warm. Commands pass from the machine agent through the certified safety channel to the drives, and no path goes around it. A software fault can never drive the carrier outside its certified safe envelope. The Brain assigns every move and re-plans routes each second, so carriers never queue at the same stack.
Today vs IC
Power, drive and speed: today’s straddle carriers beside the IC design
Today · 4-high straddle carrierIC design
Operation1 driver per carrier; automated fleets run driverless inside fenced areas with remote exception handlingNo cab and no driver. Exceptions go to the terminal’s remote desk
PowerDiesel-electric at 20–21 L/h or hybrid at 12–13.5 L/h; electric versions carry 533 kWh (453 usable) and run 5–10 h533 kWh pack, 6.5 hr per charge, 350 kW charging; no genset
Energy per move≈ 2.5–6 kWh≈ 1.75 kWh (≈ 70 kWh/hr at 40 moves)
DriveDiesel-electric or battery to 4 hub-motor wheels4 × 130 kW direct-drive hub motors, all 8 wheels steered to ±90°
Speeds≈ 24 km/h (4-high); hoist 24 m/min empty, 20 at 40 t, 16 at 50 t24 km/h; hoist 48 m/min empty, 24 at 40 t, 18 at 60 t
Weight69–72 t≈ 72 t
The IC column is the design shown on this page. Sources for the Today column are listed in BUILD_NOTES.md.
Runs on The Brain
Every movement of this machine is planned by The Brain’s orchestration layer, mirrored in the port’s digital twin, and re-planned the moment reality drifts.
See how it works →