How to model vehicle with TRAILER / without TRAILER?

[Bernd Welter]

The following usecase is quite generic within tour optimization and therefore I would like to describe how to model this:

• We have a fleet with multiple vehicles we can utilize.
• For some of the vehicles we can consider an optional trailer which means:
  • If a trailer is attached to the vehicle it's COSTS and CAPACITIES change.
  • The optimization should check whether a trailer is meaningful or not for a certain vehicle.
• Bonus: some orders may prohibit a trailer vehicle to serve them.

Now here's the proper modeling approach - based on a single vehicle named "TheVehicle4711" (If you get this for a single vehicle you can easily derive how to use this in multiple vehicles):

• Define a so-called Resource "Resource-4711" which is free of costs and limited to maximumVehicles=1:

  Code: Select all

  {
    "id" :"TheVehicle4711",
    "minimumBufferDuration" : 0,
    "constraints" : {
       "maximumVehicles" : 1
    },
    "costs": null,
    "categories" : ["Cat-Res-4711"]
  }
  

• Create two alternative vehicle objects : one with the trailer based properties (higher capacity, higher costs)

  • Code: Select all

    {
      "id" : "vehicle-4711-no-trailer",
      "requiredResourceCategories": [ "Cat-Res-4711" ],
      ...
    }
    

  • Code: Select all

    {
      "id" : "vehicle-4711-with-trailer",
      "requiredResourceCategories": [ "Cat-Res-4711" ],
      ...
      "categories": ["hasTrailer"]
    }
    

• For the bonus requirement: forbid "hasTrailer" vehicles to serve certain orders:
  • use constraints.combinations.orderVehicle:

    Code: Select all

    {
        "combinations": {
          "orderVehicle": [
             "type": "FORBIDDEN_COMBINATION",
             "orderCategory": "no-trailer",
             "vehicleCategory" : "hasTrailer"
          ]      
        }
    }
    

  • Mark the critical orders as "no-trailer" category:

    Code: Select all

    {
       "id" ; "order-23",
       "properties": {
          "categories" : [ "no-trailer" ]
       }   
    }