Skip to content
Physical AIby Santi

06Reference framework

A common language for robotics beyond the factory

Four axes to classify any non-industrial robotic system (humanoids, quadrupeds, autonomous vehicles and drones) by technology maturity, operational safety and return on investment.

Last reviewed: 2026-11Methodology & sources →

01 · Scope & overview

Robotics for places nobody designed for robots

The framework covers platforms that operate outside controlled industrial settings: extreme dynamics, unstructured infrastructure and hostile or changing conditions. We classify progress across four physical forms.

  • HUM

    Humanoids

    Bipedal systems with dexterous manipulation, built to use tools and infrastructure designed for humans.

    4 in the explorer

  • QDR

    Quadrupeds

    Articulated legged platforms with high traction and stability on uneven terrain, stairs and rock.

    5 in the explorer

  • UGV

    Ground vehicles

    Wheeled or tracked systems for cargo transport, logistics and long-range inspection.

    4 in the explorer

  • UAV

    Drones & aerial robots

    Rotary or fixed wing for monitoring, vertical inspection, express logistics and swarms.

    5 in the explorer

02 · Strategic objectives

From the vendor catalog to the operational need

Close the operational gap

Connect what robotics vendors can do with what operations actually need.

Business needsTech capabilities
24/7 inspection without exposing staffL4 autonomy + auto-docking
Operate without GPS coverageVisual / LiDAR SLAM
Cover large areasFleet or swarm coordination
See through smoke and darknessThermal + radar fusion

Standardize the criteria

A shared vocabulary to assess any platform with three questions:

01
Maturity
Which autonomy level does it sustain, and in which operational domain?
02
Safety
When and how does a human step in, and what happens if the link is lost?
03
ROI
When does it pay back against manual operation, including total cost of ownership?

The four axes

Every robot is described by four coordinates

They are categorical and independent dimensions: a drone can have high autonomy and no coordination, and a humanoid can have rich perception and teleoperated control.

Axis 1 · Autonomy & decision making

Six levels, from teleoperation to distributed autonomy

The level describes the typical operational autonomy in real deployments, not the brochure maximum. Select a level to see which platforms in the explorer sit there today.

This 0–5 scale is a framework adapted by this site for non-industrial robotics. It draws on the SAE J3016 levels of driving automation and the ODD concept, but it is not an official standard and does not replace certification.[ANSI Blog, 2021][ISO, 2021]

L4

High autonomy

Operates continuously without human intervention inside a bounded operational design domain (ODD).

◆ Human roleManages the fleet and the ODD

Key: the operational design domain (ODD)

Level 4 only makes sense within an explicit ODD: geography, weather, lighting, obstacle types and speeds. The same robot can be L4 in a known substation and L2 on new terrain.[Fraunhofer IKS]

Axis 2 · Networking & multi-robot coordination

From the isolated robot to swarm intelligence

The communication topology determines scale, resilience and what happens when a node fails.

  • Standalone

    5 platforms

    No inter-robot communication; each unit operates in isolation.

    • No network dependency
    • Scale = number of operators
    • Isolated failure
  • Coordinated

    13 platforms

    Shares state and telemetry through a base station or central server.

    • Base station or cloud
    • Central fleet planning
    • Single point of failure
  • Collaborative swarm

    0 platforms

    Decentralized decisions over a peer-to-peer mesh; tasks are allocated by each node's capability and position.

    • Peer-to-peer mesh / MANET
    • Dynamic task allocation
    • Graceful degradation
Go deeper into resilient swarms →

Axis 3 · Perception & environment observation

No sensor sees everything: fusion is the key

Every modality has a blind spot. Mature platforms combine several to keep localizing and detecting in darkness, fog, dust or without GNSS.

  • 3D LiDAR

    10/18
    + Adds:
    Precise 3D geometry, day and night
    − Limit:
    Cost; degraded by dense fog and rain
  • Stereo cameras / VIO

    6/18
    + Adds:
    Lightweight, the basis of GPS-free VIO
    − Limit:
    Needs light and texture
  • RGB-D depth cameras

    5/18
    + Adds:
    Dense depth at short range
    − Limit:
    Short range, sunlight-sensitive
  • RGB cameras

    11/18
    + Adds:
    Rich semantics for vision models
    − Limit:
    No direct depth; fails in darkness
  • Thermal / infrared

    7/18
    + Adds:
    Sees heat: people, leaks, hot spots
    − Limit:
    Low resolution, no color or texture
  • mmWave radar

    2/18
    + Adds:
    Sees through fog, dust and smoke; measures velocity
    − Limit:
    Low angular resolution
  • GNSS / RTK

    9/18
    + Adds:
    Centimeter global position with RTK
    − Limit:
    Useless underground or under jamming
  • IMU

    18/18
    + Adds:
    High-rate motion, always available
    − Limit:
    Drift grows without corrections
  • 2D LiDAR

    0/18
    + Adds:
    Cheap and reliable for indoor planes
    − Limit:
    Single plane: misses high or low obstacles
  • Tactile / haptic sensors

    1/18
    + Adds:
    Force and slip during manipulation
    − Limit:
    Only informs on contact
  • Ultrasonic

    1/18
    + Adds:
    Cheap proximity, transparent surfaces
    − Limit:
    Short range, low precision
  • Acoustic / leak ultrasound

    2/18
    + Adds:
    Gas or air leaks and bearing faults
    − Limit:
    Industrial ambient noise
  • Gas detection

    0/18
    + Adds:
    Hazardous gas concentration
    − Limit:
    Point measurement, needs calibration
  • PTZ zoom camera

    2/18
    + Adds:
    Optical zoom to read gauges from afar
    − Limit:
    Narrow field of view

Sensor fusion & SLAM

Simultaneous localization and mapping (SLAM) lets a robot know where it is without GPS. The typical pipeline has five stages:

  1. 01
    Sensors

    LiDAR, cameras, IMU, wheel or leg odometry

  2. 02
    Front-end

    Feature extraction and visual-inertial (VIO) or LiDAR odometry

  3. 03
    Filter

    Extended or unscented Kalman filter (EKF/UKF) fusing estimates at high rate

  4. 04
    Back-end

    Factor-graph optimization and loop closure to correct drift

  5. 05
    Map + pose

    A consistent 3D map and the robot's position in it

GPS-denied localization

In tunnels, mines, indoors or under interference, GNSS disappears. VIO estimates motion by comparing successive frames with the IMU; LiDAR SLAM aligns point clouds; and loop closure recognizes previously visited places to cancel accumulated drift.

Axis 4 · Control & operation modes

From the FPV pilot to the learned policy

The control mode tells how much of the behavior is written by an engineer, executed by a pilot or learned by a neural network.

◆ Human-dependentLearned / autonomous ●
  1. 01

    FPV piloting

    Low-latency video links (<50 ms) for maneuvers in tight spaces. The pilot is the perception system.

    1/18
  2. 02

    Teleoperation

    The robot stabilizes and protects itself; the human decides every move. The basis of data collection for imitation learning.

    15/18
  3. 03

    Supervised mission

    Recorded or scheduled missions the robot repeats; the operator approves exceptions from a console.

    14/18
  4. 04

    BVLOS fleet

    One operator supervises several units beyond visual line of sight. Requires detect-and-avoid and regulatory authorization.

    4/18
  5. 05

    Learned policy (RL/VLA)

    Networks trained with reinforcement learning or vision-language-action models, often with physics-informed neural networks (PINN) for gait and manipulation.

    8/18

Sim-to-real: train in simulation, deploy in the world

Locomotion policies are trained for millions of steps in parallel simulators with domain randomization (friction, masses, latencies, sensor noise) so they survive reality. The residual gap is closed with field fine-tuning and teleoperation data.

  1. Massive simulation
  2. Domain randomization
  3. Deployment
  4. Field tuning

Putting it to work

How to apply the taxonomy when assessing a vendor

Each axis translates into verifiable questions. Ask for evidence of real operation in a domain similar to yours, not staged demos.

  1. Autonomy

    Question: In which specific operational design domain (ODD) has the claimed level been demonstrated?

    Evidence to request: Real mission logs with human interventions per hour and their causes, under conditions comparable to yours.

  2. Coordination

    Question: What does each robot do if it loses the link to the base station or the cloud?

    Evidence to request: Documented disconnection behavior: which tasks continue, which are suspended and how the mission resumes.

  3. Perception

    Question: Which sensors are in the configuration being offered, not the catalog, and how does it localize without GNSS?

    Evidence to request: Tests with dust, rain, low light or reflections and the localization accuracy achieved at your site.

  4. Control

    Question: Which part of the mission is teleoperated, and how was the learned policy trained and validated?

    Evidence to request: Validation process (simulation and real data), update cadence and how a release is rolled back.

  5. Specifications

    Question: Under which conditions was each figure measured, and what is the runtime with your actual payload?

    Evidence to request: A spec sheet with test conditions (payload, speed, temperature) and a trial with your configuration.

Visualization methodology

Why we don't use radar charts

The axes of this taxonomy are qualitative and non-linear. A radar chart assigns them arbitrary numbers, and the polygon area — what the eye reads — changes with nothing more than the order of the axes.

Same data, different axis order

Order A31%Visual area
Order B43%Visual area

The same robot looks “more capable” in one order than in the other.

What we recommend

Parallel coordinates chart

Draws a continuous profile for each model across vertical axes, revealing design and maturity patterns without forcing a single scalar score.

Open the chart →

Interactive classification matrix

A two-dimensional interface crossing autonomy level with coordination capability to map system architectures.

Open the matrix →

What about the market?

The “tasks × market” automation matrix (use case, robot family, autonomy, sensor fusion and estimated ROI) lives in the ROI calculator.

See the automation matrix →