SAT tests and AGV fleet scaling: from pilot to full deployment

The pilot has confirmed that the system works in one area — now it needs to be rolled out across the whole shop floor and formally accepted. This stage completes the implementation project: it covers controlled scaling of the fleet and AGV SAT tests (Site Acceptance Test), i.e. acceptance testing of performance, integration and safety carried out at the customer's site. It is the eighth, penultimate step of the step-by-step AGV implementation methodology — it follows the pilot and crew training and precedes routine operation. Below we show what really changes with a larger fleet, what the acceptance report looks like and where scaling most often falls down.

AGV fleet scaling: from pilot to full deployment

Scaling means extending the operation of the AGVs and AMRs to all planned areas and shifts. If two vehicles worked on one shift in the pilot, the target may be a full fleet working around the clock. The key rule: do not do it in one leap. Expand the system in stages — first add vehicles on one shift in all zones, then start the second shift, closely observing the fleet's behaviour at every step. Some problems only emerge at a larger scale, and a gradual transition does not paralyse the whole of production at once.

The advantage of a well-designed AGV system is precisely its ease of expansion — adding more vehicles or routes is usually simpler than with traditional, permanently installed conveying systems. This flexibility comes with a condition, however: the infrastructure, navigation and task assignment logic must be designed from the outset for the target number of vehicles, not just the number in the pilot.

What changes with a larger fleet

Going from two vehicles to more than a dozen is not the same work repeated several times. As fleet density increases, three areas of risk grow non-linearly:

• Traffic at intersections. With two vehicles, meeting on a narrow section is rare; with more than a dozen, traffic conflicts at junctions become an everyday occurrence. This is exactly where congestion appears that the single-area pilot did not show — two AGVs blocking each other's path can hold up a whole chain of subsequent missions.
• Task priorities. With a small fleet, almost every order can be handled immediately. Under full load, the system has to decide which missions are more urgent, how to arrange the queue and what to do when orders arrive faster than the vehicles can complete them. Poorly chosen assignment rules lead to situations where one line waits while vehicles circle around another.
• Battery charging. A single vehicle goes to the station when there happen to be no orders. More than a dozen vehicles working on all shifts need a planned charging rhythm so that it does not turn out at peak hours that half the fleet is sitting at the chargers. The number and location of stations and the chosen strategy — opportunistic or cyclical charging — determine the real availability of the fleet.

That is why scaling is carried out "in plain sight" of the team and the supplier: every added vehicle or shift is an opportunity to check whether the system still maintains the planned cycle times at the new traffic density. The goal is a smooth transition from pilot mode to normal operation, without a sudden jump in the number of stoppages.

AGV SAT tests — performance, integration and safety

Once the fleet is operating at the target scale, a formal Site Acceptance Test is carried out together with the supplier or the AGV and AMR system integrator. This is the moment to verify whether the delivered system meets all the requirements set out in the contract and the design. SAT is divided into four blocks, which are best worked through according to a checklist agreed in advance.

Functional tests. Each type of transport mission is performed several times and the system's behaviour is checked under various conditions — with an occupied drop-off station, with an obstacle on the route, after a sudden vehicle stop. The aim is to confirm that the system copes not only with the ideal scenario but also with everyday disruptions.

Performance tests. These measure whether the system achieves the agreed parameters: whether the fleet completes the planned number of transport runs within an hour, and whether the response time to an order stays within the agreed limit. If specific KPIs have been defined in the contract, this is the moment to compare them with reality under full load.

Integration tests. All interfaces are verified — whether orders from the WMS are always correctly received by the AGV system and whether data on completed transport runs is returned to the higher-level systems. The acceptance condition is strict: no "manual workarounds", everything must work automatically.

Safety tests. Emergency situations are triggered deliberately. A person or a truck appears on the route — will the scanners stop the AGV? The safety button is pressed — do all the vehicles stop? Connectivity is lost — does the system switch to a safe state? Every element of the safety system must work as documented, without exception.

Acceptance report and end-user acceptance

Technical tests are not everything. Operators and warehouse staff — the people who will use the AGVs every day — need to be involved in assessing the system. The question is simple: does the system allow them to do their work the way they expected? Their acceptance is as important as the green boxes on the checklist, because it determines whether the crew will trust the new fleet rather than work around it.

Once all tests have been passed successfully and the last defects have been remedied, the official acceptance takes place. It is worth drawing up an acceptance report in which both parties confirm that the requirements have been met or record minor open points to be addressed later. This document formally closes the implementation project and marks the point from which the system moves into normal operation and responsibility for day-to-day running passes to the plant's team.

Typical scaling pitfalls

Most problems at this stage stem from the same recurring mistakes. It is worth knowing them in advance:

• Big-bang rollout. Launching the full fleet on all shifts at once instead of in stages. When a problem arises at high traffic density, it immediately affects the whole of production.
• Charging infrastructure planned for the pilot. The number of stations that was enough for two vehicles becomes a bottleneck as the fleet grows and work runs on all shifts.
• Priority rules not tested under load. Assignment logic that worked without queues breaks down when orders arrive faster than the vehicles can complete them.
• SAT treated as a formality. Skipping deliberate emergency tests or operator acceptance backfires later — most often in the form of workarounds and a lack of trust in the system.
• No acceptance report. Without written agreements, it is difficult to settle later what was within the scope of supply and what is a change going beyond the contract.

Summary — scaling and acceptance step by step

Full deployment comes down to a few orderly steps:

1. Expand the fleet in stages — further zones, then further shifts — observing the system as traffic density increases.
2. At the larger scale, verify three areas of risk: intersections, task priorities and the charging rhythm.
3. Carry out SAT in four blocks: functional, performance, integration and safety tests, according to the checklist in the contract.
4. Involve operators and warehouse staff in the assessment — without their acceptance, sign-off is incomplete.
5. Draw up an acceptance report with any open points and formally close the project.

Well-executed scaling limits risk at every stage, and a thorough SAT provides hard proof that the system delivers what you paid for. Signing the acceptance report marks the start of the fleet's real work — and the final step of the methodology: operation, maintenance and continuous improvement.

How does SAT differ from pilot testing?

The pilot checks whether the concept works on a narrow slice of the process and allows the system to be fine-tuned in practice. SAT is the formal acceptance of the entire system at the target scale, assessed against the requirements set out in the contract — it covers functional, performance, integration and safety tests, and its outcome is confirmed by an acceptance report. The pilot is for learning; SAT is for settling the delivery.

Why not launch the entire fleet at once?

Because some problems — conflicts at intersections, task queues, a shortage of charging stations — only emerge at high traffic density, which the single-area pilot did not show. Adding vehicles and shifts gradually makes it possible to catch these problems locally, without stopping the whole of production.

What should an AGV acceptance report contain?

Confirmation that the requirements of the contract and the design have been met, the results of the SAT tests (functional, performance, integration and safety), end-user acceptance and a list of any open points to be addressed later. It is the document that formally closes the implementation project and marks the start of the operating phase.

Sources

• Myzer — How to successfully implement AGVs in your factory: a comprehensive educational guide (acceptance tests, scaling, transition to continuous operation)