Estimate AMR wheel torque, speed and DC demand for custom drive system design. Adjust the example below, then use the guide to plan component validation.
Straight-line powertrain estimate
Wheel torque · steady / peak
27.8 / 120.6 N·m
Per wheel; 2 driven wheels, 1350 kg gross.
DC current · steady / peak
21.0 / 91.0 A
Whole vehicle traction at 48 V nominal; excludes auxiliaries.
Concept assumptions, not component ratings. Straight travel, equal wheel load and clean dry floor only. Safety, thermal performance and dynamic load transfer remain unvalidated. See formulas and limitations.
Architecture, traction and environment assumptions
Drive Wheel Count
2 — follows topology.
40–95 %; required.
-25–55 °C; required.
Efficiency and tread coefficients are illustrative constants, not measured supplier properties. Duty and ambient are captured for review; they do not establish a thermal rating.
Estimate details and open checks
Wheel speed
143.2 RPM
At 1.5 m/s. Motor RPM needs the selected gear ratio.
Tractive force · steady / peak
556 / 2412 N
Whole vehicle; grade and acceleration assumed simultaneous.
Mechanical power · steady / peak
834 / 3618 W
Whole vehicle at target speed; wheel output, before drivetrain losses.
Static traction ratio
2.32×
Assumed grip / peak demand; no dynamic weight transfer or turning model.
Grade holding allowance
29.8 N·m/wheel
Chosen 1.5× static grade factor; not a motor brake rating or stopping check. Zero grade still needs a parking review.
Illustrative downhill regen
2509 W peak
Assumed 1.2 m/s² stop. Resistor resistance, pulse energy and BMS acceptance require hardware data.
Engineering validation pending
Thermal feasibility, tread lifetime, stopping distance and scanner protective fields are unknown. Obtain the actual torque/time cycle, derating curves, brake response and worst-case floor tests before releasing the design.
Published by AMRDriveUnit. First recorded . Method and source review: every six months, or when cited requirements change. Send corrections through the engineering inquiry form.
Five decisions the estimate can support
Use the tool to establish a concept demand, then close the unknowns below. The focus is complete drive system architecture; mounting details and catalog selection have separate guides.
Separate wheel demand from motor selection
Wheel torque follows force × wheel radius / driven wheels. A motor rating additionally needs reduction ratio, speed, losses and the complete duty trace.
At equal electrical power, doubling voltage halves DC current. With the same wire resistance, cable I²R loss falls to one quarter. Cable mass and inverter efficiency do not follow automatically.
The example static grip ratio compares assumed floor friction and wheel load with demand. It does not model pitch, suspension or lateral forces; confirm the worst loaded wheel on the real route.
A regen peak does not select a resistor or prove a stop. Check pulse energy, repetition, BMS acceptance and the drive manufacturer limits, then test loaded stopping performance.
Confirm product classification and placement date. The transition to Regulation (EU) 2023/1230 does not make this concept tool a conformity assessment.
This is an idealized longitudinal force balance, not an ISO formula or component certification. Let m be payload plus chassis mass in kg; g = 9.80665 m/s²; θ = atan(grade / 100); a = speed / acceleration time; r = wheel diameter in metres / 2; N = driven wheels.
Reproducible sizing equations
Output
Equation
Boundary
Steady force (N)
Fsteady = m × g × cos(θ) × Crr + m × g × sin(θ)
Constant speed on the selected uphill grade
Peak force (N)
Fpeak = Fsteady + 1.10 × m × a
Chosen inertia approximation; constant acceleration and grade together
Wheel torque (N·m)
T = F × r / N
Equal wheel sharing; motor shaft torque needs reduction ratio
Wheel RPM
speed × 60 / (2 × π × r)
No tire compression or slip correction
DC power and current
Pdc = F × speed / η; Idc = Pdc / nominal voltage
η = assumed transmission efficiency × 0.90 motor efficiency; auxiliary loads and voltage sag omitted
Static grip ratio
μ × m × g × cos(θ) × driven share / Fpeak
Fixed assumed friction; no CG transfer, cornering or suspension model
Grade holding allowance
1.5 × m × g × sin(θ) × r / N
Chosen wheel-side allowance; brake location and losses unvalidated
Example downhill stop; 1.2 m/s² is assumed, not a mandated deceleration
The traction flags below 1.05× and 1.35× are internal review thresholds. A higher ratio does not establish safe performance. Inputs outside the supported domain withhold both results and export.
Demand calculation: Mass + grade + acceleration → Whole-vehicle tractive force → Wheel torque + speed demand.Electrical interpretation: Mechanical traction power → Divide by assumed efficiency → Divide by nominal bus voltage.
Choose the motion topology before detailed sizing
Engineering comparison, not measured odometry or payload rankings. The tool covers straight travel on conventional wheels only.
Choose the motion topology before detailed sizing
Architecture
Useful capability
Cost or mismatch to investigate
Differential, 2 driven wheels
Straight travel and spot rotation
No direct lateral travel; pivot scrub and castor drag excluded
Dual swerve, 2 driven wheels
Steered translation in different directions
Steering actuator power, cable routing and calibration excluded
Quad swerve, 4 driven wheels
Distributed driven contacts
More controlled axes; uneven loading can defeat equal sharing
Steered trike, 1 driven wheel
Simple steering architecture
Turning envelope and available driven load constrain the mission
Mecanum, 4 driven wheels
Lateral travel without steering axes
Roller vector forces need a different model; calculator output is withheld
Kinematic comparison and declared model boundary; no universal payload band is asserted.
Compare transmission and motor envelopes
Tool efficiencies are illustrative inputs for comparison, not guaranteed performance of a gearbox family.
Compare transmission and motor envelopes
Concept option
Efficiency assumed here
Evidence required before selection
Planetary
0.92
Ratio, torque-speed map, backlash, bearing load and mounting drawing
Cycloidal
0.86
Load-dependent efficiency, starting drag, shock limits and lubrication
Hypoid
0.89
Drive/backdrive losses, mounting orientation and thermal dissipation
Direct drive path
0.96 path × 0.90 motor
No reduction advantage; verify continuous torque and hub thermal path
AMRDriveUnit concept assumptions. Missing supplier test curves remain unknown; no shock rating or packaging dimension is inferred.
Compare DC voltage at equal electrical power
Worked comparison at 2,400 W electrical traction demand; current = power / voltage. Actual demand varies with efficiency and battery voltage.
Compare DC voltage at equal electrical power
Nominal bus
Ideal current at 2,400 W
Cable loss for the same R, relative to 24 V
24 V
100 A
1.00×
48 V
50 A
0.25×
96 V
25 A
0.0625×
Algebraic comparison, not a cable-sizing table. Select wiring, protection and voltage ratings from actual limits; nominal voltage alone does not establish electrical safety.
Replace assumed grip with route measurements
The model uses fixed illustrative (Crr, friction μ) pairs: NDI PU (0.012, 0.65), standard PU (0.018, 0.55), ESD PU (0.016, 0.58), soft PU (0.024, 0.72). These are not certified material properties.
Replace assumed grip with route measurements
Operating condition
Why the estimate may fail
Minimum next step
Clean, dry, straight indoor route
Actual wheel and floor may differ from the example
Measure drawbar drag and grip at representative loads
Wet, dusty, oily or worn floor
Assumed dry friction is inapplicable
Measure a lower-bound coefficient; derate acceleration and grade
Uneven floor or changing payload
Static driven load share misses wheel unloading
Measure individual contact loads through the route
Freezer, outdoor or towed trailers
Cold drag, environment and trailer forces are excluded
Use a route-specific model and supplier qualification
Model limitations and proposed measurements. A ratio above 1 does not verify safe traction.
Close thermal and mechanical unknowns
The calculator captures duty and ambient conditions for handoff. It has no winding temperature, RMS load spectrum or fatigue-life model.
Close thermal and mechanical unknowns
Unknown
Decision risk
Validation evidence
Motor and inverter continuous rating
A short acceleration peak may dominate repeated-cycle heating
Torque/speed/time trace, loss maps and stabilized temperature test
Tread compound and hub
Load, speed and temperature affect deformation and bonding
Wheel supplier load/speed/temperature data; endurance test
Wheel bearing and axle
Cantilever moment and floor shocks may dominate
Individual bearing loads, geometry and supplier fatigue calculation
Housing-to-chassis thermal path
A sealed housing may reject insufficient heat
Mounting contact, interface resistance and worst-ambient validation
Engineering validation checklist. No generic tread blowout temperature, heat-sink thickness or bearing lifetime is claimed.
Keep braking functions and validation separate
The selected brake plan records intent. It does not establish brake capacity or a safety performance level.
Keep braking functions and validation separate
Function or estimate
What it can tell you
What remains open
Static grade holding allowance
Wheel-side torque using a chosen 1.5× gravity allowance
Actual factor, gearbox backdrive, brake location, wear and parking test
Motor controlled deceleration
Can return energy into the DC link
Available torque under faults, traction, BMS and power loss
STO / safety-related controls
Control safety must be assessed as a system
Stopping sequence, required PL, hardware diagnostics and validation
Scanner protective field
Requires a validated stop and response chain
Worst-case measured stopping distance, sensor tolerances and field configuration
ISO public scope supports a design methodology, not universal PL ratings or response times. Use the relevant truck standard and actual device manuals.
Tool output assumes downhill deceleration at 1.2 m/s² and uses the same illustrative drivetrain efficiency in reverse. It is not a prescribed emergency deceleration.
Use the regen estimate to request hardware data
Required input
Why it matters
Alternative or mitigation
Battery charge acceptance versus state and temperature
The BMS may limit or interrupt returned energy
Validate absorption at full charge and low temperature
Drive clamp voltage and permitted resistor range
An arbitrary resistance can overload the chopper
Follow the selected drive manual; no resistor ohms are recommended here
Stop time, energy and repetition
Peak watts alone do not establish pulse or average rating
Integrate braking power over time and verify cooling/duty limits
Failure and mechanical stopping behavior
A resistor does not establish power-loss stopping
Validate the whole braking architecture on the vehicle
Beckhoff demonstrates the distinction between peak and continuous braking power for a specific axis. Obtain the AMR drive manufacturer data for an actual selection.
Choose customization only when the constraint warrants it
Procurement comparison based on engineering judgment. Price, NRE, MOQ, lead time and savings are quote-dependent and currently unknown.
Choose customization only when the constraint warrants it
Decision dimension
Catalog route
Custom route
Early proof of concept
Useful when an existing envelope and ratings fit
Useful when catalog constraints block the architecture
Mechanical fit
Check adapters, suspension and service access
Specify interfaces, load paths and tolerances before releasing CAD
Engineering cost and schedule
Confirm stock, integration work and test availability
Obtain scoped NRE, prototype milestones and validation responsibilities
Production and service
Check supply continuity and replacement interchangeability
Agree tooling ownership, revision control and lifecycle spares
Decision framework only; no universal BOM saving, mass reduction or delivery promise.
Confirm the legal framework and supply scope
Reviewed 2026-10-25. Confirm the actual product classification and placement date with the responsible supplier and integrator. The tool makes no claim that a selected drive is compliant or that a document has already been issued.
Machinery framework transition
Framework
Where PCM classification applies
What to confirm
Directive 2006/42/EC, before the general transition
Article 13; declaration of incorporation in Annex II 1.B; assembly instructions in Annex VI
Applicability to the supplied assembly and final machine integration responsibilities
Regulation (EU) 2023/1230, generally from 20 January 2027
Article 11; EU declaration of incorporation in Annex V Part B; assembly instructions in Annex XI
Transition provisions, scope, documentation and product placement date
The incorporation route does not demonstrate conformity of the completed robot. Marking obligations under other applicable legislation must be assessed separately; a blanket “no CE” statement is inappropriate.
Illustrative calculations, not customer deployments or measured outcomes. Each uses the same formulas and declared coefficients as the tool. Changing duty or ambient does not create a validated thermal prediction.
Actual tool execution, captured 25 October 2026. Default pallet example: 1,000 kg payload + 350 kg chassis, 1.5 m/s in 1.2 s, 3% grade, two 200 mm driven wheels, 48 V; planetary efficiency 0.92 × motor efficiency 0.90, NDI PU example, 65% driven load. Continuous duty, holding brake planned, 25 °C. Compact crop of the preset and result; site navigation and floating contact controls are outside the crop. Software evidence only, not measured hardware performance or customer social proof.
Pallet AMR: grade and acceleration together
Inputs: 1000 + 350 kg; 1.5 m/s in 1.2 s; 3% grade; 200 mm wheels; 2 driven wheels; 48 V.
Assumptions: planetary; ndi-vulkollan; 65% static driven load share. All other constants follow the method above.
Steady / peak wheel torque
27.8 / 120.6 N·m
Wheel speed
143.2 RPM
Whole-vehicle DC current, steady / peak
21.0 / 91.0 A
Use the simultaneous grade/acceleration result as a concept demand. Ask for motor torque-speed curves and verify worst-case traction before picking a ratio.
Light AMR: compare 24 V with 48 V
Inputs: 220 + 80 kg; 1.8 m/s in 0.8 s; 2% grade; 160 mm wheels; 2 driven wheels; 24 V.
Assumptions: planetary; standard-pu; 70% static driven load share. All other constants follow the method above.
Steady / peak wheel torque
4.5 / 34.2 N·m
Wheel speed
214.9 RPM
Whole-vehicle DC current, steady / peak
10.1 / 77.4 A
Keeping this same demand and efficiency, changing to 48 V halves estimated bus current. Confirm battery/controller ratings rather than inferring a wire gauge.
Heavy carrier: four driven wheels
Inputs: 2500 + 500 kg; 1 m/s in 1.5 s; 6% grade; 250 mm wheels; 4 driven wheels; 96 V.
Assumptions: cycloidal; high-traction-pu; 85% static driven load share. All other constants follow the method above.
Steady / peak wheel torque
77.1 / 145.8 N·m
Wheel speed
76.4 RPM
Whole-vehicle DC current, steady / peak
33.2 / 62.8 A
Equal load sharing reduces per-wheel demand in this calculation. Measure the least-loaded wheel and add steering demand before accepting a four-module design.
Turn the estimate into a validation plan
Use acceptance criteria agreed for the actual mission and applicable requirements. The following checks define evidence to request, not a ready-made safety approval.
Traction uncertainty: Measure wheel loads + floor grip → Recheck worst route and payload → Set and validate motion limits.Prototype release: Demand + component data → Loaded thermal and braking tests → Resolve open checks before release.
Prototype validation evidence
Decision
Evidence to collect
Mitigation or alternate path
Torque and control sizing
Torque-speed map, current logs and actual acceleration at loaded voltage
Increase ratio, relax acceleration or select a larger drive
Traction and stopping
Worst-case load, floor, grade, brake delay and full stopping tests
Reduce speed/grade demand, change load sharing or brake architecture
Thermal endurance
Representative repeated duty at worst ambient until temperatures stabilize
Derate the cycle, improve heat rejection or select a larger continuous rating
Regen and power failure
DC-link voltage, BMS behavior, pulse energy and loss-of-power behavior
Validate an energy sink and mechanical stopping/holding strategy
Commercial release
Quote, NRE, supplier drawings, documented scope and agreed test ownership
Use a catalog prototype if customization has not earned its schedule/cost
Does the tool calculate motor torque or wheel torque?
Wheel output torque per driven wheel. Motor shaft torque additionally needs the chosen gear ratio and gearbox efficiency; motor speed and the torque-speed envelope must also be checked.
What does steady torque mean here?
Torque to maintain target speed on the selected grade with the example rolling resistance. It is a mission demand, not a verified continuous motor rating.
Can I size a Mecanum system here?
No. Roller vector forces and direction-dependent losses need a separate model. Selecting Mecanum withholds estimates and export; send the mission and motion directions for engineering review.
How does wheel diameter change the result?
For fixed required force, wheel torque grows with radius. At fixed vehicle speed, wheel RPM falls as diameter grows. Ground clearance, floor joints and the actual tire rolling resistance require separate checks.
Are the tread and gearbox values measured product data?
No. They are explicitly labeled concept assumptions for comparing sensitivity. Replace them with supplier curves and measurements before component selection; no material temperature limit or backlash rating is implied.
Does a favorable traction ratio mean the robot is safe?
No. It only means assumed static grip exceeds the modeled straight-line demand. Dynamic wheel unloading, turns, contamination and local contact differences can invalidate it.
Electrical and thermal
Does 48 V always outperform 24 V?
No. At the same power it halves bus current, and at the same wire resistance cable loss is one quarter. Battery, controller and motor compatibility, voltage excursions, cost and efficiency still need comparison.
Are DC bus current and motor phase current the same?
No. The tool divides whole-vehicle electrical traction power by nominal bus voltage. Phase current depends on torque, motor constants and inverter operation; the tool cannot choose a phase-current limit.
Can the duty setting verify thermal feasibility?
No. It records the intended moving/rest fraction for review. Supply the torque and speed trace, cooling path, losses and temperature limits to validate repeated acceleration and continuous operation.
Does the regen peak select a braking resistor?
No. The selected drive clamp voltage, minimum resistance, current limit, pulse energy, repetition and cooling must be known. Battery absorption and failure behavior are also part of the architecture.
Braking and product scope
Is the 1.5× holding allowance an ISO requirement?
No. It is a chosen concept allowance on static grade torque at the wheel. The final factor and brake rating must follow the application assessment, applicable requirements and supplier data.
Does the page specify a scanner protective field?
No. Field length requires measured worst-case stopping, the full response-time chain and device-specific margins. This page provides neither a certified stopping distance nor a scanner configuration.
Is every drive unit partly completed machinery?
Do not infer classification from a product name or this calculator. Confirm the intended function, supplied assembly and applicable legislation with the responsible supplier and integrator.
When does Regulation (EU) 2023/1230 generally apply?
Its general application date is 20 January 2027, with some provisions applying earlier. Check the placement date, transition provisions and actual product scope. Do not treat a reference to the future framework as a current certification.
Handoff and procurement
What should I send with the exported brief?
Add CAD envelope, actual wheel loads, floor and grade measurements, torque/speed/time duty trace, voltage range, control interface, quantity and validation requirements. Thermal and safety unknowns remain listed in the brief.
What if the calculator or clipboard is unavailable?
Restore example inputs or correct the highlighted fields. For unavailable Mecanum sizing, send your mission profile for review. You can manually select the valid brief, email it, or use the contact RFQ form; without JavaScript the default example and guide remain readable.
Sources, review date and evidence boundaries
Reviewed 2026-10-25. Public standard summaries support their scope only; they are not evidence of clause-specific thresholds or certification of this tool. Numerical coefficients and scenarios are labeled engineering assumptions. No customer field-test evidence is claimed.
ISO 3691-4:2023
Public scope: driverless industrial truck safety and verification. The catalog entry does not substantiate the previous fixed braking, scanner margin or muting numbers. Full requirements must be checked for the application.
Public scope: design and integration methodology for safety-related controls. It does not prescribe a universal required performance level for every application.
For the pre-transition machinery framework, check Article 13, Annex II 1.B and Annex VI when the supplied assembly is partly completed machinery. Confirm scope and placement date for the actual product.
General application from 20 January 2027; some provisions apply earlier. For a product classified as partly completed machinery, consult Article 11, Annex V Part B and Annex XI. A calculator cannot determine classification or demonstrate conformity.
Manufacturer example showing that regenerative peak and continuous power both matter. It is an axis-specific example, not a resistor selection rule for every AMR or an endorsement of this tool.
Copy the concept brief above and paste it into Project Summary on the RFQ form. Add your CAD envelope, duty trace, actual floor conditions and quantity. Ask the engineering team to confirm feasibility, documentation and delivery scope.
