Warehouse pick-path routing methods: S-shape, return, midpoint, and largest gap

Aisle network

Create nodes and permitted paths for aisle ends, cross aisles, depot points and constrained segments. Add direction and turn restrictions rather than allowing the model to cross racks or barriers.

• Use measured distances
• Tag one-way segments
• Version layout changes

Pick coordinates

Assign stable aisle, bay, level and position coordinates to every sampled pick. Reconcile unmapped and duplicated locations before comparing routes.

• Keep sequence timestamps
• Retain quantity and handling unit
• Flag inaccessible slots

Representative lists

Select lists across line counts, density, zones, shifts and peaks. Avoid proving a method on only the order family that favors it.

• Stratify the sample
• Include low-density work
• Preserve service classes

Observed execution

Measure walking or driving, pick, search, wait, congestion and exception time. Distance is one driver; observed elapsed and quality outcomes decide whether the route is useful.

• Use comparable operators
• Record overrides
• Check accuracy

S-shape for dense aisle demand

Consider S-shape where entered aisles usually contain picks across their depth and through-travel is permitted. It is simple to teach but can add distance for sparse work.

Return for sparse picks near one end

Consider return routing where picks cluster near the access end or through-travel is impractical. Reversals and shared access need operational review.

Midpoint for two-ended access

Consider midpoint rules where both aisle ends are accessible and splitting the aisle reduces deep entry. Define how lists and workers choose the access end.

Largest gap for variable sparse work

Consider largest-gap logic where lists vary and the system can identify the biggest empty segment reliably. Validate instruction clarity and route stability.