Electric rotary
Robot joints, EV traction, factory servos.
nlt143 research / april 2026
what is an actuatorand how does it work
A first-principles reference for builders, operators, and investors working at the intersection of construction, robotics, and physical AI.
manufacturing is cpu · real estate is storage · transport is network · actuators are the write head
01/ what is an actuator
An actuator is the device that turns a signal into motion.
Every actuator, from a Boeing 787 flap motor to a piezoelectric fuel injector, has the same three ingredients.
1
A power source.
Electrical, hydraulic, pneumatic, chemical, or thermal energy that the device can draw on.
2
A converter.
The element that translates that power into useful mechanical work. The motor, the cylinder, the crystal.
3
A control input.
A signal, often small, that commands position, velocity, force, or torque.
remove any of the three and the device stops being an actuator.
02/ the physics
30% to 95%typical actuator efficiency range
Every actuator is a chain of energy conversions. Each link in the chain has its own efficiency. The product of those efficiencies sets the ceiling.
torque = Kt × current
Brushless DC motor torque constant Kt links current to torque output.
force = (2π × η / L) × torque
Ball screw conversion. L is lead per revolution, η is efficiency.
F_net = mass × acceleration
Newton’s second law. Net force after friction, gravity, payload.
V_back_emf = Ke × angular_velocity
Back-EMF caps the no-load speed at a given supply voltage.
bond graph: energy domains
| domain | effort | flow | power |
|---|---|---|---|
| Electrical | Voltage (V) | Current (A) | V × A |
| Translational | Force (N) | Velocity (m/s) | N × m/s |
| Rotational | Torque (N·m) | Angular velocity (rad/s) | N·m × rad/s |
| Hydraulic | Pressure (Pa) | Flow rate (m³/s) | Pa × m³/s |
| Pneumatic | Pressure (Pa) | Mass flow (kg/s) | Pa × m³/s |
| Thermal | Temperature (K) | Entropy flow (W/K) | T × dS/dt |
03/ anatomy of a representative actuator
A 200 mm electric linear actuator, dissected.
The drawing above shows a typical industrial linear actuator. A brushless DC motor drives a ball screw through a planetary gearbox. The screw rotates inside a non-rotating push tube, which extends and retracts. Clevis ends couple to the load.
actuator spec sheet
Stroke200 mm
Force2.5 kN
Max speed50 mm/s
Lead5 mm/rev
Repeatability±0.05 mm
Cycle life10⁷ cycles
Power350 W peak
Mass1.8 kg
total latency, command to motion, 1 to 5 ms.
04/ the eleven families
Eleven families do all the work.
Practically every actuator in production today belongs to one of these eleven families. The first five do the bulk of the world’s work. The other six fill specialty niches that the first five cannot reach.
Electric linear
Window blinds, hospital beds, satellite solar arrays.
Stepper
3D printers, CNC machines, camera focus rings.
Hydraulic
Excavators, aircraft control surfaces, hydraulic presses.
Pneumatic
Factory pick-and-place, brake systems, soft robotics.
Piezoelectric
Microscope stages, fuel injectors, ultrasonic transducers.
Shape memory alloy
Aerospace deployables, medical stents, micro-grippers.
Electrostatic
MEMS mirrors, micro-pumps, switches in DLP projectors.
Magnetostrictive
Sonar, precision tooling, vibration cancellation.
Dielectric elastomer
Artificial muscles, soft robotics, haptic surfaces.
Pyrotechnic
Airbag deployment, satellite separation bolts, ejector seats.
05/ how to choose
Selection is five questions, in order.
Most actuator misallocations come from skipping question one. Engineers reach for the family they know, then back-fit the load to the device. Reverse the flow.
- 1How much force or torque does the load require, peak and continuous.
- 2How fast must it move, and how often.
- 3How precisely must it stop.
- 4What is the environment.
- 5What is the cost target.
06/ the market
The chokepoint is priced and growing.
Sources cited: Yole Group humanoid actuator forecast, Valuates Reports robotics market sizing, IDTechEx humanoid robotics outlook, Goldman Sachs humanoid TAM analysis.
$150M
2024 humanoid actuator market
$9.86B
2030 base case forecast
80%
compound annual growth rate
humanoid actuator market, 2024 to 2035
$ billions, three scenarioswho is building
Eight humanoid OEMs setting the cadence.
Tesla
OptimusMillions per year by 2030Vertically integrating actuators in-house. Linear and rotary modules custom for the platform.
Figure AI
Figure 02100k units in commercial pilotBMW pilot live. Custom actuator stack with proprietary motor and gearbox pairing.
Apptronik
ApolloMercedes-Benz manufacturing partnerApptronik builds actuators in-house. Series elastic actuators tuned for safe human contact.
Agility Robotics
DigitAmazon, GXO warehouse deploymentsBipedal logistics specialist. Hydraulic legacy roots, now hybrid electric stack.
Unitree
G1, H1Consumer-priced humanoids$16k starting price for G1. Aggressive supply chain leverage out of Hangzhou.
BYD
Internal humanoid programFactory deployment in BYD plantsVertical integration. Actuator supply through existing EV motor production lines.
AgiBot
RAISE A1, A2Mass production targets in ChinaBacked by HongShan, Tencent. Tight integration with domestic actuator supply chain.
UBTECH
Walker S1Industrial pilots with NIO, BYD, FoxconnPublic on the HKEX. Deepest portfolio of automotive humanoid pilots in China.
07/ strategic implications
What this means, by audience.
industrial operators
Treat actuator supply as a strategic input. Single-vendor lock-in is the same exposure as single-source semis was in 2021.
robotics builders
Vertical integration of actuators is now table stakes for cost and IP defensibility. The companies winning own their motors.
capital allocators
The actuator layer is where physical AI economics get decided. Picks and shovels with a longer half-life than the platforms.
policy makers
Domestic actuator capacity is a national security input. China’s humanoid actuator supply chain is two to three years ahead.
construction and infrastructure builders
Actuators are the labor substitution layer. The cost curve through 2030 will reset what is buildable, by whom, at what scale.
08/ downloads
Five companion artifacts.
The full research pack as PDFs. Free, attribution requested. Cite as NLT143 Research, 2026.
PDF8 KB · 3 pages
Actuator Technical Guide
First-principles technical reference. Physics, families, selection, and a representative spec sheet.
download
PDF8 KB · 3 pages
McKinsey-Style Market Analysis
TAM, SAM, SOM. Cost curve through 2030. Supply chain map. Strategic implications by audience.
download
PDF6 KB · 3 pages
Deloitte-Style Strategic Playbook
Capability model, operating model, risk register, build-buy-partner decision tree.
download
PDF14 KB · 13 panels
Executive Briefing
Boardroom-ready. Thirteen panels covering thesis, market, playbook, and the ask.
download
PDF7 KB · 3 pages
Market Model Summary
TAM/SAM/SOM scenarios, BOM share, supplier landscape, unit economics.
download
Manufacturing is CPU.
Real estate is storage.
Transport is network.
Actuators are the write head.
david t phung / nlt143 research / april 2026
davidtphung@nlt143.energyx.com/davidtphung