## Body
- Platform: humanoid, bipedal
- Mass: 38 kg (with 4.1 kWh pack)
- Degrees of freedom: 23 — 7 per arm, 6 per leg, 3 neck
- End effector: 3-finger parallel gripper, 60 N grip, 30 Hz tactile array
- Frame: right-handed, X forward, Y left, Z up, origin at pelvis
- Envelope: 1.42 m standing, 0.78 m folded, shoulder width 0.46 m

## Sensors
| Sensor | Rate | Resolution | Range | Mounting | Noise | Latency |
|---|---|---|---|---|---|---|
| Head RGB-D | 30 Hz | 1280x720 | 0.3-4.0 m | head_link, +90 mm Z | 5 mm at 2 m (measured) | 42 ms (measured) |
| IMU | 400 Hz | 16-bit | +/-16 g, +/-2000 deg/s | pelvis | 0.02 g rms | 3 ms |
| Joint encoders | 1000 Hz | 0.01 deg | absolute, 23 joints | each joint | none | 1 ms |
| Force-torque | 200 Hz | 200 N / 20 Nm | 6-axis | wrists, ankles | 0.4 N rms | 6 ms |
| Battery | 1 Hz | 0.1 V | 0-100% | torso | n/a | 1 s |

## Actuators
- Legs: series-elastic, 120 Nm peak, 45 Nm continuous
- Arms: quasi-direct-drive, 34 Nm peak
- Control mode: position, 1 kHz bus
- End-to-end latency: 18 ms (measured)
- Thermal: derate from 65 C winding, cut off at 80 C
- Backlash: 0.3 deg at the wrist

## Limits
- Payload: 3 kg sustained, 6 kg peak for 30 s maximum
- Speed: 0.4 m/s near people, 1.2 m/s otherwise
- Duty cycle: 40 min active, 25 min charge, 10 min thermal recovery
- Environment: -5 C to 40 C, indoor, dry floor
- Prohibited: stair descent with payload above 2 kg; operation on wet flooring

## Safety envelope
- E-stop: hardware, cuts actuator bus power in under 20 ms; software cannot re-enable
- Human proximity: 0.6 m standoff; reduced to 0.2 m only in handover mode
- Handover mode: gripper force below 20 N, speed below 0.1 m/s, operator in view
- Autonomy ceiling: no operation with a human inside the swept volume
- Failure behaviour: hold position on watchdog loss, controlled sit on bus loss
- Never: disable the E-stop; override a standoff; descend stairs loaded
- Last verified: 2026-10-28

## Control interface
- Observation: 50 Hz — 23 joint positions, 23 joint velocities, IMU quaternion, IMU rates, depth frame at 224x224, gripper state, previous action
- Action: 20 Hz — 23 normalized target positions in [-1, 1], clipped
- Episode: 60 s maximum, reset on any fault
- dtype: float32

## Simulation
- Model: assets/robot.xml (MuJoCo), matched to hardware within 2 mm on link lengths and 3% on mass
- Twin: Isaac Lab for RL training; MuJoCo is the reference for sim2real checks
- Randomisation: friction 0.8-1.1, latency 12-24 ms, mass +/-5%
- Known gap: contact is over-stiff on soft flooring; expect 3-5 cm foot slip on carpet