An AMR speed rating is not a fleet throughput plan

Maximum speed answers a narrower question

A mobile robot's maximum travel speed does not establish how many loads a fleet can deliver in a shift. Productive capacity also depends on demand timing, loaded and empty routes, acceleration and deceleration, traffic, docking, load transfer, charging, blocked paths, endpoint availability and recovery.

The buyer's requirement should therefore begin with material flow: what must move, between which endpoints, by when and with what lateness or shortage consequence. Vehicle speed is one input to that system requirement—not the output being purchased.

Define demand by route and time window

An hourly average can hide the period that actually determines fleet size. If a batch of movements is required in one production burst, spreading that demand across the whole shift produces a different question and an optimistic answer.

• Name every origin, destination, load type, handling unit and required transfer interface.
• State deliveries, loads or material quantity by route and time window, including start-up, breaks, changeovers, peaks and end-of-shift work.
• Define the service rule: due time, maximum wait, priority, allowed backlog and consequence of a missed movement.
• Separate confirmed demand from forecasts and design allowances, and keep the source and review date for each input.
• Record upstream and downstream capacity, because an unavailable machine, door, lift, conveyor or hand-off point can hold a robot and change the fleet requirement.

Build the complete mission clock

OTTO by Rockwell Automation says its fleet estimates consider average speed, docking time, driving distance, charging, throughput distribution, traffic rules and an efficiency factor. It also says attachment type, approach angle, congestion, doors and intersections can alter the estimate. This is useful manufacturer guidance about estimation inputs, not independently verified proof that an OTTO fleet or another system will achieve a buyer's target.

• Dispatch and queue time before the robot can begin the mission.
• Empty travel to pickup and loaded travel to delivery using the permitted route and direction.
• Waiting at intersections, doors, lifts, crossings, shared aisles and controlled zones.
• Approach, alignment, docking, load transfer, confirmation and departure at both endpoints.
• Charging, inspection, cleaning, planned service and the operating allowance for routine recovery or reassignment.

Use the routed system, not straight-line distance

VDMA's Layout Interchange Format represents a mobile-robot layout as nodes, edges and stations, with vehicle restrictions and information used in deadlock handling. The guideline is non-binding and does not provide a universal throughput formula, but its system model illustrates why a calculation should use the actual route graph, permitted vehicle classes, directions and station relationships rather than a ruler line across a drawing.

ISO 3691-4:2023 defines a driverless-truck system as including the truck, control system, guidance means and power system, and says operating-zone condition significantly affects safe operation. ISO's public page says this edition is expected to be replaced by a draft now under development. That safety scope does not calculate throughput, but it reinforces that route and operating-zone assumptions cannot be detached from the configured system or altered only to make a capacity model look better.

• Record usable aisle and doorway widths, one-way rules, passing points and speed or access restrictions by route segment.
• Model shared resources and their capacity: endpoints, buffers, doors, lifts, intersections, chargers and manual hand-off areas.
• Include loaded geometry, stability limits and attachment behaviour where these change routes, speed, docking or transfer time.
• State the traffic priority and deadlock rules, including what happens when a preferred route or destination is unavailable.

Make charging part of the capacity plan

A runtime maximum is not productive shift coverage. The estimate should identify the exact vehicle, battery and charger configuration; expected energy use by mission and load state; charge thresholds and policy; charger locations and capacities; travel and queue time to charge; and the response to a missed dock, unavailable charger or degraded battery.

MiR currently claims that its MiR250 can operate for up to 13 hours with maximum payload and up to 17 hours 30 minutes with no payload, with a charging ratio of up to 1:16. MiR also states that specifications can vary with local conditions and application setup. OTTO publishes different 10%–90% charge times for its named models and says charge speed influences fleet size, charger count and floor-space use. These are manufacturer claims for particular products and stated conditions, not independent proof of productive duty or charger capacity at a buyer's site.

Require an inspectable fleet estimate

A3's current R15.08 catalogue separates requirements for the industrial mobile robot, system integration and day-to-day use. Those are safety scopes, not throughput guarantees. A capacity model or trial must not be presented as completing the applicable risk assessment or proving compliance.

• Identify the model, software, attachments, payload states, fleet count, charger count, layout and interface versions used.
• List every demand, route, speed, dwell, traffic, charging, availability and recovery assumption with its source, date and owner.
• Show which hard constraints pass, fail or remain unverified; extra capacity cannot compensate for a failed safety, load, geometry or integration gate.
• Keep hand calculation, simulation, supplier estimate, trial observation and production observation as different evidence types.
• Show sensitivity to peaks, longer dwell, congestion, charger or endpoint loss and other assumptions that materially change the recommended fleet.

Validate the peak, degraded and recovery cases

Before acceptance, freeze the fleet, software, maps, traffic rules, endpoints, attachments, interfaces, chargers, load set and measurement method. Exercise representative peak demand and variation, then introduce agreed degraded cases such as a blocked route, occupied destination, failed transfer, unavailable charger, network loss and manual recovery. Record queue time, mission time, completed and late movements, charger and endpoint contention, interventions, rejected missions and every test deviation.

Recalculate and retest affected cases after a material change to demand, layout, load, vehicle, attachment, software, route rules, charger, endpoint, door or lift interface, operating hours or recovery method. Preserve the earlier result as evidence for the old configuration rather than carrying its conclusion forward.

Keep every claim inside its evidence boundary

VDMA, ISO and A3 are authoritative for the published scopes and status cited here, but none verifies a named fleet estimate or deployment. OTTO and MiR are authoritative for their own published product claims and guidance; those statements remain manufacturer evidence until the proposed configuration is tested under the buyer's conditions.

RobotAtom records demand, assumptions, configuration, source dates, evidence type, unknowns and required validation. It does not certify fleet throughput, safety, suitability or regulatory compliance. Qualified operations, integration, engineering and safety owners must decide what applies and whether the evidence is sufficient for the actual application.