Robot Movement¶

How robots navigate through the warehouse.

Movement Model¶

Edge-Based Travel¶

Robots move along edges between nodes:

[Node A] ──── edge (6m) ────> [Node B]
   │                              │
   t=0                         t=4s

At speed 1.5 m/s: 6m / 1.5 = 4 seconds

Speed¶

Constant speed during travel:

robots:
  speed_m_s: 1.5

Travel Time Calculation¶

travel_time = edge_length / robot_speed

Pathfinding¶

Shortest Path¶

Default: Find path with minimum total distance.

A ──3── B ──2── C
│               │
4               3
│               │
D ──────5────── E

Shortest A→E: A→B→C→E (8m)
Not: A→D→E (9m)

A* Algorithm¶

Efficient pathfinding using heuristic:

f(n) = g(n) + h(n)

Where:

g(n): Actual distance from start
h(n): Estimated distance to goal (Euclidean)

Congestion-Aware Routing¶

Optional: Avoid congested areas:

routing:
  policy: congestion_aware
  congestion_weight: 1.5

Cost becomes:

cost = distance + weight × congestion_score

Movement Events¶

Timeline¶

t=0:   Robot at Node A, assigned task at Node D
t=0:   Path calculated: A → B → C → D
t=0:   Start moving on edge A→B
t=3:   Arrive at Node B
t=3:   Start moving on edge B→C
t=5:   Arrive at Node C
t=5:   Start moving on edge C→D
t=9:   Arrive at Node D (destination)

Event Types¶

Event	Description
`StartEdgeTraversal`	Begin moving on edge
`EndEdgeTraversal`	Arrive at destination node
`PathBlocked`	Cannot proceed (congestion)
`PathRerouted`	Alternative route taken

Traffic Interaction¶

Waiting for Access¶

When next node/edge is occupied:

Robot waits at current node
Monitors for availability
Proceeds when clear

Rerouting¶

When path is blocked and rerouting enabled:

Detect blockage
Calculate alternative path
Resume movement on new path

Speed Variations¶

Constant Speed (Default)¶

robots:
  speed_m_s: 1.5

All robots same speed, always.

Speed Distribution¶

Variable speeds across fleet:

robots:
  speed_m_s:
    distribution: normal
    mean: 1.5
    stddev: 0.2

Loaded vs. Unloaded¶

Different speeds when carrying items:

robots:
  speed_m_s: 1.5
  loaded_speed_m_s: 1.2

Turn Handling¶

Simplified Model¶

Turns are instantaneous (no turn time).

Turn Costs (Optional)¶

Add time penalty for turns:

routing:
  turn_penalty_s: 0.5

Affects path selection - may prefer straighter routes.

Example Movement Trace¶

[10:00:00.000] Robot R1: Assigned task T1, destination N15
[10:00:00.001] Robot R1: Path calculated [N1→N5→N10→N15], distance 12.0m
[10:00:00.002] Robot R1: Starting edge N1→N5 (length 4.0m)
[10:00:02.668] Robot R1: Arrived at N5
[10:00:02.669] Robot R1: Starting edge N5→N10 (length 4.0m)
[10:00:05.336] Robot R1: Arrived at N10
[10:00:05.337] Robot R1: Starting edge N10→N15 (length 4.0m)
[10:00:08.004] Robot R1: Arrived at N15 (destination reached)

Performance Factors¶

Travel Efficiency¶

Path quality: Shorter paths = faster completion
Congestion: Waiting time reduces efficiency
Layout: Well-designed maps minimize travel

Bottleneck Identification¶

Look for:

High-traffic edges
Frequently blocked nodes
Long average wait times