Lesson 8 · Several fleets and who may go where

Real plants rarely run one kind of vehicle. A fleet is a group of identical AGVs with its own size, speed and battery, and stations can be reserved to some fleets. You will add a slower, bigger fleet for Line 2's heavy pallets and keep the two kinds of work apart.

Time
30 min
Start from
the checkpoint of lesson 7
You will learn
  • define a second fleet with its own shape, size, battery and motion
  • give a fleet its own starting bay, off the main flow
  • restrict stations to fleets and check that the restriction works

Open your project from lesson 7, or its checkpoint.

What a fleet is

A fleet bundles everything that is the same for a group of vehicles: name, shape, size, battery and, if you want, motion. Between fleets these may differ; within a fleet they never do. AGVs are numbered in fleet order: with three platforms and one heavy truck, AGVs 1 to 3 are platforms and AGV 4 is the truck.

SettingRestarts the run?
name, shape (how it is drawn)no
count, size, battery, clearance, scanners, motionyes

Add the heavy fleet

  1. Rename the first fleet. In Simulate, open the Vehicles tab. One card is the fleet you have been using. Change its name to Platforms. Names are free text and shown in station properties, placement messages and results.
  2. Add a fleet. Click Add fleet. A second card appears, with a preview of the vehicle in its true proportions. Name it Heavy, set Type to Forklift AGV, AGV count to 1, Length to 2400 and Width to 1200 (millimetres).
  3. Choose its battery. Set the battery to lead-acid. Autonomy (8 h) and charge time (8 h) appear when the battery model is on; you will switch it on in the next lesson.
  4. Slow it down. On its card set Straight speed to 60 cm/s and Curve speed to 30; open Advanced settings and set Acceleration to 30 and Deceleration to 50. Every fleet has its own speeds; a speed set on a path still wins.
Note

Advanced settings also holds a safety clearance added on every side of the vehicle and the ranges of the front and rear scanners. The traffic model protects the vehicle's real rectangle plus that clearance, so a bigger body or margin makes it keep more distance, and in tight places it can make it block others. Leave them at their defaults here.

A bay of its own

The new fleet needs a starting station, and the Network tab and the Fleet step both say so until it has one. Rather than put it on the loop, where a parked vehicle is an obstacle for everyone behind it, give it a short bay off the main flow.

  1. Draw the bay. In Draw choose Path (4), click on the bottom side at (−7 500, −6 000) and then (−7 500, −9 000): a 3 m branch below the loop.
  2. Place the charger. Choose Station (7) and click near (−7 500, −8 500). Name it Charge heavy and tick Charger.

Who may use which station

With two fleets, every station that has a role shows a list, Permitted fleets, in its properties. By default every fleet may use every station. Untick a fleet and it can no longer pick up, drop off, charge, park or start there; it may still drive through. At least one fleet always stays ticked.

  1. Reserve Line 2 to the heavy fleet. Select Line 2, and in Permitted fleets untick Platforms. Only Heavy may now load or unload there.
  2. Reserve the charger. Select Charge heavy and untick Platforms: the platforms cannot start or park in the bay.
  3. Keep the heavy fleet off Line 1. Select Line 1 and untick Heavy, so that the slow truck does not take Line 1's work away from the platforms.

Behind the scenes the rule is simple: an order goes only to a vehicle whose fleet is permitted at both its pickup and its drop-off. Goods in is open to both fleets; Line 1 takes platforms only; Line 2, and the transport from Line 2 to Repack, take the heavy truck only. An order that no placed fleet can serve stays queued, with the reason shown in the Movements dock.

Tip

The placement order is also a rule: the fleet with the fewest permitted starting stations is placed first, so a fleet with a reserved charger always finds it free.

Run and check

  1. Look at the scenario. In the Scenario tab, Fleet now reads 4/4 AGV · 2 fleets: all four vehicles found a starting station. The three platforms start on the loop's chargers and the truck in its bay.
  2. Run one hour and watch the dock. Start the simulation at 10× and open Movements. Orders to Line 1 are always taken by AGVs 1 to 3, orders to and from Line 2 always by AGV 4. In Fleet usage each bar is labelled with its AGV and fleet.
What you should see
  • Four vehicles in two colours of body size, throughput close to the previous lesson's, and no platform ever seen at Line 2.
Try it yourself
  1. Open Goods in and untick Platforms there, then run. Line 1 orders now find no fleet permitted at both their pickup and their drop-off, so they queue, and the Movements dock says exactly that. Restore the tick afterwards.
  2. Raise the heavy fleet to 2 vehicles. The step reads 4/5 AGV: why? Add the starting station that is missing and check it again.
  3. Read Fleets for the VNA option on the same card; you will use it in lesson 10.

Checkpoint

Goods inLine 1Line 2Charge 1Charge 2Charge 3RepackCharge heavy
The plan at the end of this lesson: the plant with a heavy-fleet bay below the bottom side

It contains: 10 paths · 8 stations · 1 traffic zone · 4 AGVs · 2 fleets · 13 workflow blocks.

Download the checkpoint (aurora-08-fleets.en.sim)

Open it with Project›Import project. It replaces the project you have open, so save yours first (or open it in a new browser tab). Anything you do from here on is a copy: the checkpoint file itself never changes. Use it to continue from here if you skipped a lesson, or to compare your own project with the expected one.