Compiler Comparison

Asimov v0 vs HUMA Kits

Asimov published an open-source lower-body humanoid (12 DOF, ENCOS motors, MuJoCo sim). We ran their specs through our build compiler. It does not compile — and the reasons why tell you everything about what “open source” really means when half the robot is missing.

Compile Status Overview

Asimov v0
DOES NOT COMPILE
4 errors, 3 warnings
12 DOF (lower body only)
No battery, compute, or sensors
ENCOS motors (no verified supplier)
Kit 00 (Sub-$10K)
COMPILES
0 errors, 4 warnings
18 DOF (full body)
$10,198 BOM cost
19.1 kg total mass
Kit 01 (Entry)
COMPILES
0 errors, 5 warnings
22 DOF (full body)
$11,211 BOM cost
28.3 kg total mass
Kit 02 (Mid)
COMPILES
0 errors, 6 warnings
28 DOF (full body)
$20,308 BOM cost
28.2 kg total mass
Kit 03 (Pro)
COMPILES
0 errors, 6 warnings
32 DOF (full body)
$61,652 BOM cost
43.9 kg total mass

Asimov v0 Compile Results

Each check below is what our compiler would produce if Asimov's BOM were submitted. Since their ENCOS motors aren't in our verified parts catalog, we run a virtual compile against their published specifications.

Electrical[error]
No battery pack in BOM
Asimov v0 is lower-body only. No power system is included in the open-source release.
!
Communication[warning]
No motor controller in BOM — CAN bus interface unverified
ENCOS motors use CAN protocol but no controller board or CAN gateway is specified in the v0 release.
!
Mechanical[warning]
Hip pitch rated torque marginal: 40 Nm rated vs 45 Nm required (peak 120 Nm is fine)
For a ~70 kg full humanoid, each hip supports 21 kg at 0.22 m lever. Rated torque (40 Nm) leaves <5% margin for continuous walking.
Mechanical[ok]
Knee torque OK: 75 Nm peak (276% of 27 Nm required)
Mass Budget[error]
Cannot verify mass budget — no upper body, frame, battery, or compute mass
Lower body structural: 15.9 kg + motors: 6.1 kg = 22.0 kg (legs only)
Software[error]
No compute module in BOM
Asimov provides MuJoCo sim + PPO training code but no onboard compute hardware spec. Cannot assess AI capability tier.
!
Availability[warning]
ENCOS motors have no verified supplier URL or public pricing
Estimated lower-body motor cost: $2,200-$5,600 (legs only). ENCOS has no published list prices. Estimates based on comparable Chinese actuator pricing.
Thermal[error]
Hip roll motor (EC-A5013-H17-100) at 31% efficiency — 69% becomes heat
Continuous walking loads hip roll constantly. Without active cooling, thermal shutdown is likely within 15-30 minutes of continuous gait.

Design Flags from Teardown

Beyond compiler checks, our teardown of the Asimov v0 repo surfaced these engineering concerns. Each flag includes the compiler rule we would add to catch it automatically.

errorHip Roll Motor (EC-A5013-H17-100)
31% efficiency — 69% of electrical energy becomes heat
Serious thermal management concern in continuous walking. Will overheat without active cooling.
Compiler rule: Add thermal check: if motor efficiency < 50%, flag as error for continuous-duty joints
!
warningHip Yaw Motor (EC-A3814-H14-107)
Empirical CAN current range ±40A vs datasheet spec ±10A (4x discrepancy)
Either spec sheet is wrong or motor is being driven far beyond rating
Compiler rule: Add spec-vs-measured validation when empirical data is available
!
warningAnkle Roll Joint
Range ±5.7° (±0.1 rad) — barely adequate for terrain adaptation
Limited to flat surfaces. Rough terrain walking will be compromised.
Compiler rule: Add joint range check: ankle roll < ±10° should be warning for outdoor use
i
infoOverall Design
Lower body ONLY — no torso, arms, head, power, compute in v0
Cannot assess full-system compatibility. BOM is partial.
Compiler rule: Compiler should require minimum joint set for 'full humanoid' build
i
infoRepository Activity
Frozen since 2026-01-28. All 10 commits in 2 days. No updates in 3 months.
Community may not get bug fixes or improvements

ENCOS Motor Specifications

Asimov uses ENCOS for all 12 actuators (5 distinct models). These are the specs from their motor_parameters.md file.

ModelJointGearRatioPeak NmRated WEff.Mass (kg)Qty
EC-A6416-P2-25Hip PitchPlanetary25:112062473%0.8032
EC-A5013-H17-100Hip RollHarmonic (H17)100:19012031%0.642
EC-A3814-H14-107Hip YawHarmonic (H14)107:160134.451%0.42
EC-A4315-P2-36KneePlanetary36:17539774%0.4552
EC-A4310-P2-36Ankle (Pitch + Roll)Planetary36:13615671%0.3844
Total motor mass6.13 kg12
Motor cost estimate: $2,200-$5,600 (legs only). ENCOS has no published list prices. Estimates based on comparable Chinese actuator pricing.

What Our Compiler Catches

Missing subsystems

Asimov v0 has no battery, compute, sensors, or upper body. Our compiler requires a complete BOM — you can't ship half a robot. Three of the seven compile dimensions fail immediately on missing components alone.

3 errors

Thermal budget violations

The hip roll motor runs at 31% efficiency. Our thermal check would flag any motor below 50% efficiency on a continuous-duty joint as an error. In practice this means thermal shutdown during sustained walking without active cooling — which isn't in the BOM either.

1 error

Supplier verification gaps

ENCOS has no public distributor, no published pricing, and no verified supplier URL. Our availability check flags this. You literally cannot order these parts from a known source without contacting the manufacturer directly.

1 warning

Spec-vs-measured discrepancies

The hip yaw motor shows CAN current of +/-40A empirically vs +/-10A in the datasheet — a 4x gap. This either means the spec sheet is wrong or the motor is being driven far beyond its rating. Either way, it's a safety concern.

1 warning

Kit Compile Comparison

Our three kits are complete BOMs — battery, compute, sensors, frame, and full-body actuators. Each passes the compiler.

BuildStatusDOFMassBOM CostErrorsWarnings
Asimov v0FAIL1222.0 kg*~$3,900*43
Kit 00 (Sub-$10K)PASS1819.1 kg$10,19804
Kit 01 (Entry)PASS2228.3 kg$11,21105
Kit 02 (Mid)PASS2828.2 kg$20,30806
Kit 03 (Pro)PASS3243.9 kg$61,65206
* Asimov mass and cost are legs-only estimates. Full-system mass and cost are unknown — the remaining subsystems are not open-sourced.

Asimov Software Stack

The sim and training code is the strongest part of the v0 release. MuJoCo + PPO with terrain curriculum is a proven pipeline.

Physics
MuJoCo (≥3.4.0) + MuJoCo-Warp (≥1.11.0)
RL Framework
RSL-RL-Lib (ETH Zurich)
Task API
mjlab (fork of mujocolab/mjlab — 'Isaac Lab API powered by MuJoCo-Warp')
ML Framework
PyTorch ≥2.7.0
RL Algorithm
PPO, 5,000 iterations, 4,096 parallel environments
Policy Architecture
3-layer MLP (256, 256, 128)
Walking Frequency
1.25 Hz gait cycle gait cycle
Terrain Curriculum
Yes

Repository Metadata

Stars
699
Forks
74
Last Push
2026-01-28
License
CERN-OHL-S-2.0
Frozen since launch. One-shot release, not active dev.

The Point

Publishing a lower-body CAD file and a MuJoCo config is not the same as publishing a buildable robot. A real BOM needs to compile — every electrical, mechanical, thermal, and software dependency must resolve. Asimov v0 fails four of seven compiler dimensions before you even get to the interesting engineering questions.

HUMA kits compile. Every part has a verified supplier URL, every voltage matches, every torque budget is checked, and every compute tier is validated against the target AI capability. That is the difference between a GitHub repo and a buildable humanoid.

Source: github.com/asimovinc/asimov-v0, github.com/asimovinc/asimov-mjlab. Teardown data extracted 2026-04-20. ENCOS motor specs from motor_parameters.md. Cost estimates based on comparable Chinese actuator pricing — ENCOS has no public price list.

HUMA kits compile. Asimov v0 does not.

Every HUMA kit passes 9 compatibility checks before you spend a dollar.