PS Agent Idle Percentage
Truck matching within APS uses Theoretical No Minimum, which means that the number of trucks assigned to an individual route is not fixed to an integer and can be less than 1. This is a requirement as it means trucks become a linear variable instead of an integer variable - which means the solve time for a single instant is a fraction of a second instead of more than a minute (and consider that there are usually 2000+ individual solutions calculated in a two-week schedule run). Users can specify a minimum Agent Rate to minimise having less than one truck on a route.
Before the trucks get assigned, each Agent has a maximum productive rate at which they can operate and a minimum if the option has been enabled. Based on period objectives, the optimiser will determine the Productive Rate at which an Agent will operate whilst also ensuring the number of trucks available is not exceeded. The instantaneous trucking requirements for an Agent is equal to its production rate divided by the truck productive rate.
Instantaneous Trucks = Loader Production Rate / Truck Production Rate
Haulage Result.Truck Production Rate.Wtph = (Haulage Result.Truck Payload / Haulage Result.Times.Total) * 60
Haulage Result.Times.Total = SpotAtLoader + TruckLoadTime + LoadedTravelTime + SpotAtDump + DumpTime + UnloadedTravelTime + TKPHDelay + QueueDespite the Loader Production Rate being set in the APS Calendar. Alastri recommends ensuring the rate specified in HI closely matches this value. Mismatched rates can result in incorrect truck numbers being reported.
Idle Percentage
When the optimiser decides to run a digger at a reduced rate, this reduces the number of trucks assigned to the Agent. In reality, a reduced number of trucks under a dig unit results in a percentage of time where the digger sits idle. In APS, the idle percentage is factored into the productive dig rate resulting in idle percentage always being reported as 0. If the idle percentage is required to be calculated, it can be done by calculating the Productive Rate's reduction percentage over the Nominal Rate. This percentage value can then go onto to calculate things like the duration.
