Docs Fleet and the model

The throughput model

The whole model is four lines of arithmetic. Here they are, with a worked example and the assumptions stated plainly.

1 min read5 sections

#Inputs

Input	Where it comes from
Travel distance, m	Typed, or derived from the plan as the straight-line distance from the dock centroid to the racking centroid.
Rated speed, mm/s	The machine profile's `speed_mms`.
Handling time, s	Typed. Time to pick up and put down at each end of a trip.
Moves required	Typed. The demand — moves per shift the site must handle.
Hours per shift, days per year	Typed.
Units and shifts	From the fleet.

#The arithmetic

text

cycle_s        = (2 × distance_m × 1000) ÷ speed_mms + handling_s
moves_per_hour = 3600 ÷ cycle_s
capacity_shift = moves_per_hour × units × hours_per_shift
capacity_day   = capacity_shift × shifts

#Worked example

A counterbalance truck rated at 1600 mm/s, 96 m from dock to racking, 18 s handling, 12 units on two 8-hour shifts.

text

cycle          = (2 × 96 × 1000) ÷ 1600 + 18  = 120 + 18  = 138 s
moves per hour = 3600 ÷ 138                    = 26.1
per shift      = 26.1 × 12 units × 8 h         = 2 504
per day        = 2 504 × 2 shifts              = 5 009

If the demand is 4 000 moves a day, the fleet meets it with about 20 per cent headroom. If it is 6 000, it does not, and the page says so.

#Assumptions, stated

Steady flow. Every unit is always either travelling or handling. No waiting.
No congestion. Units do not queue at docks, block each other in aisles, or wait at intersections.
No downtime. No charging, no battery swaps, no breakdowns, no operator breaks.
Straight-line distance. The derived distance is centroid to centroid, not a routed path.

Because of these, the result is an upper bound. Real throughput is lower, sometimes substantially. Treat the model as the ceiling, and treat telemetry as the truth.

#When to use something else

If the answer to your question genuinely depends on dynamics — dock queueing at peak, charging strategy, interactions between fifty machines — take the figures from this page to a discrete-event simulation tool. That is what they are for, and Auddomate will not pretend otherwise.