How Axle Data Affects Truck Travel Time in Haul Infinity

Overview

Axle data in Haul Infinity plays a crucial role in calculating road friction forces, tire TKPH (Ton Kilometers Per Hour), and truck travel times. This data provides detailed information about the weight distribution, tire count, and drivetrain connections for each truck axle, which are essential for accurate modeling of haulage operations.

Key Points About Axle Data

1. Axle Attributes:

   • Each row in the axle data table represents one axle on the truck.
   • A “driven” axle is connected to the truck's drivetrain.
   • Each axle has a specific number of tires.
   • Weights are provided for Unloaded (Empty), Loaded (Full), and Payload conditions.

2. Total Weights:

   • Cumulative weights for unloaded and loaded conditions are shown at the bottom of the axle data pane.

3. Purpose:

   • Axle data is used for TKPH calculations and to determine travel times under full and empty conditions.

Best Practices for Axle Data Setup

• Cross-check Values: Verify the axle weights and configurations against the equipment manufacturer’s specifications.
• Account for Modifications: Adjust for any custom tray modifications that could impact axle weights.
• Consistency: Ensure the Truck Payload values in Setup Task > Parameters align with the axle data.

Impact on Travel Time Calculations

The axle data directly influences truck acceleration and deceleration, which affects travel times for unloaded and loaded conditions. If there is a mismatch between the truck payload values in the Model and Setup Task > Parameters, the calculated travel times may not reflect real-world conditions.

Example of Travel Time Calculation

In this example:

• Axle Data in the Model Step:
  • Total Empty Weight: 220 tonnes
  • Total Full Weight: 530 tonnes
  • Payload: 310 tonnes

The truck’s engine and retard forces (via rimpull curves) are used to overcome rolling resistance and manage uphill/downhill travel. For a given route, this results in a calculated travel time of 18.55 minutes.

However, if the actual truck payload at the mine site is 290 tonnes (entered as Maximum Tray Payload or Truck Utilised Payload in Setup Task > Parameters), the calculated travel time will not match the real-world scenario:

 

or:

Adjusting Axle Data

To achieve more accurate travel times:

1. Adjust the axle data to reflect the truck’s actual payload of 290 tonnes

Note: The empty weight of a truck changes only if it undergoes modifications, such as a tray replacement. Any such change will impact the unloaded cycle time.

2. Keep the payload overrides in Setup Task > Parameters consistent.

After making these adjustments:

• The recalculated travel time for the same route is 18.33 minutes.

Importance of Accuracy

Although the difference in travel time appears small in this example (~1.2%), such discrepancies can significantly impact total cycle time and scheduling, especially in mid- and long-term schedules.

Recommendations

• Regularly review and update axle data to align with the latest equipment specifications and operational conditions.
• Conduct validation checks to ensure travel times in the model reflect actual performance on-site.

By maintaining accurate and consistent axle data, Haul Infinity can provide precise calculations for cycle times, enabling more reliable scheduling and operational planning.

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