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Performance Settings |
Performance Settings
To access this dialog:
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Select a haul truck item in the Scheduling Setupdialog. Activate the Performance tab.
The Performance panel is used to select a performance model type. The contents of the Model Settings group will change based on the selected model type.
This panel is provided as part of Haul
Trucks settings.
The following groups of controls are available on this panel, accessible using one of the radio buttons on the left.
- Linear: select this option to define a linear model type.
- Rimpull and Retardation: select this option to define a Rimpull and Retardation model type.
Gradients, Speeds and Stopping Distances
The vehicle speeds are entered with reference to a specified gradient, this is typically the ramp gradient used in the mine and will be in the range 8 to 10%. The reference gradient should include the Rolling Resistance (RR), which is typically around 2% for a well maintained haul route. For example, if the ramp gradient is 8% (8m vertical lift per 100m horizontal distance) and RR is 2% then the reference gradient is 10%.
The vehicle speeds are given for the reference gradient for loaded and empty, for up, down and flat gradient scenarios. This allows for all possible combinations of haul route configuration.
The speed on any other gradient can be calculated as a linear function of the speed difference on the flat (loaded or empty) and the speed on the reference gradient (loaded or empty). This is a reasonable linear approximation of the Rimpull Pull or Retardation curves for most haul trucks.
Acceleration distance at the start of each road segment is calculated from the Vehicle Specifications and Vehicle Performance curves. This means that if a vehicle is travelling at a constant speed when entering a new road segment and the effective gradient changes then the accelerating or decelerating force can be computed. This is used to determine the acceleration or deceleration distance and time. The terminal speed for the new road segment will depend on:
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The length of the road segment relative to the acceleration distance
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The vehicle performance characteristics (speed vs effective gradient)
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The effective gradient of the road segment
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The maximum speed allowed on the road segment
At the end of each haul route the vehicle will slow down at the dumping point or at the loader. This distance is entered by the user as “Stopping Distance” and this distance is added to the total length of the haul. This can be seen by inspecting the haul route log .
Sourcing Rimpull and Retardation Model Parameters
Rimpull and Retardation data is supplied by haul truck manufacturers; please refer to their data tables for the relevant modeling parameters if you wish to use this option.
Defining and Using Stopping Distance
Stopping distance is the distance the truck takes to de-accelerate at the end of the outward journey to the Destination and on the inward journey to the Loader.
In the case of the outward journey this distance is added to the route length and represents the turnaround distance when dumping. Similarly a turnaround distance is also added to the inward journey.
Acceleration or de-acceleration distance (AccelDist)
is computed in ISTS
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Less than the maximum speed (Vmax) if VStart < Vmax
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Greater than the maximum speed (Vmax) if VStart > Vmax
Where:
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Vmax is the minimum of the theoretical speed (calculated from the vehicle performance settings, effective gradient) and the maximum allowable speed for the road segment.
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VStart is the vehicle speed at the start of a road segment, which will be equal to Vend for the previous road segment or zero if this is the first segment of a road.
How Distance is Computed
Distance is computed between two Nodes that define a road or the distance between two points of a road string that connect the two Nodes.
Therefore, when digitising roads with short segment lengths that are less than the de-acceleration distance, it is quite feasible that the calculated terminal speed (Vend) will be greater than the specified maximum speed for the road segment. This is a limitation of the methodology, which could be overcome by having a “look ahead” function to start slowing the truck down before reaching the start node of the road segment.
This potential over-speed can be compensated for by limiting the speed on the approach segment.
Defining Linear Model Parameters
To access this group:
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Select a haul truck item in the Scheduling Data Setup dialog. Activate the Performance tab. Select the Linear radio button.
Field Details:
Rel Effective Gradient (%): enter a value (%) for the relative gradient.
Max Effective Gradient (%): enter a value (%) for the maximum effective gradient.
Minimum Speed (km/h): enter a value (km/hr) for the minimum truck speed.
Speed Loaded (km/h) - Up(+): enter a value (km/hr) for the uphill loaded truck speed.
Speed Loaded (km/h) - Down(-): enter a value (km/hr) for the downhill loaded truck speed.
Speed Loaded (km/h) - Flat: enter a value (km/hr) for the flat loaded truck speed.
Speed Empty (km/h) - Up(+): enter a value (km/hr) for the uphill empty truck speed.
Speed Empty (km/h) - Down(-): enter a value (km/hr) for the downhill empty truck speed.
Speed Empty (km/h) - Flat: enter a value (km/hr) for the flat empty truck speed.
Stopping Distance (m): enter a value (m) for the truck stopping distance.
Defining Rimpull and Retardation Model Settings
To access this dialog:
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Select a haul truck item in the Scheduling Data Setup dialog. Activate the Performance tab. Select the Rimpull and Retardation radio button.
Field Details:
Loaded grid:
Effective Gradient (%): enter a value (%) for an effective gradient when the truck is loaded.
Speed (km/hr): enter a speed value (km/hr) for the loaded truck.
Rimpull (kg x 1000): enter a Rimpull value (kg x 1000) for a loaded truck.
Empty grid:
Effective Gradient (%): enter a value (%) for an effective gradient when the truck is empty.
Speed (km/hr): enter a value (km/hr) for an empty truck speed.
Rimpull (kg x 1000): enter a Rimpull value (kg x 1000) for an empty truck.
Stopping Distance (m): enter a value (m) for the truck stopping distance.
Graph Type: select
Speed vs Rimpull or Gradient
vs Speed to change the type of graph displayed in the right-hand
pane.
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You need to define all Rimpull and Retardation parameters before applying changes. |
