AGV fleet sizing
About this app
The AGV exercise to work through: loaded and empty trips, handling and waiting add up to the total working time and from it the number of vehicles. Two platforms simulate single transports and accompanying transport side by side; the calculation shows every step with from-to matrix and formulas, plus the break-even processing time.
With explain mode: an AI tutor walks you through the app, points out what matters in the scene and answers your questions.
The calculation behind the fleet size
The number of automated guided vehicles a system needs follows from the total working time (TWT): the vehicle time per hour for loaded trips, empty trips and handling, plus waiting at machines if the vehicle accompanies the product. Loaded travel comes from a from-to matrix of transports and the distances in the layout. Empty travel depends on the dispatching rule. One vehicle delivers 60 minutes times availability η per hour, so the fleet size is ⌈TWT / (60 min · η)⌉.
What you see
The basis is an exercise with one load/unload station and two machines on a one-way track, and three products with fixed routes and hourly quantities. Two platforms simulate two logics in parallel: in logic A the AGV only takes a product to the next station (single transports); in logic B it accompanies the product through all stations. A six-step worked solution leads from distances via the from-to matrix and empty trips to the vehicle count, always with the current numbers.
Experiments
Logic B saves handling and empty trips but ties up the vehicle during every machining step. Change the processing time per station: the comparison panel shows the break-even point above which logic A pays off and below which logic B needs less vehicle time. Switch the empty-trip estimate between lower bound, random dispatching and “empty = loaded” to see how much the assumption matters. You can also change the one-way network to two-way traffic.
Frequently asked questions
- How do you calculate the number of AGVs needed?
- Add up the vehicle time per hour for loaded trips, empty trips, loading and unloading and any waiting into the total working time. Divide it by the usable time of one vehicle, which is 60 minutes times availability. Round the result up to the next whole number.
- How do you estimate empty travel for an AGV system?
- A lower bound comes from the balance at each station: empty trips are only needed where more vehicles are required than become free. Random dispatching, where the vehicle drives to the pickup point of the next order after each delivery, is more realistic. A conservative estimate sets empty travel equal to loaded travel.
- What is a from-to matrix?
- A from-to matrix lists how often goods are moved between each pair of stations per time unit. Rows are sources, columns are destinations. Combined with the distance matrix it gives the total loaded travel time.
- Do the calculation and the simulation agree?
- Not exactly, and the app shows the difference. In logic A the simulated empty trips are usually shorter than estimated because the nearest AGV takes the job. In logic B waiting times at busy machines are added.
Subject: Technical logistics & intralogistics
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