Figure 1: Acceleration, Traction and Retarder settings in Haul Infinity
The settings in the acceleration section limit the max change in speed the truck can experience. With the above settings for the max acceleration, we allow the truck to change its speed by 1.5 km/h per second. The other settings subsequently determine the limit for deceleration (loaded and unloaded). The settings should not be changed from these default settings.
Traction:
Coefficient of traction: friction value between the road and the tyres of the truck
Braking reliance on traction: standard value 0.7 – this means that you leave a safety margin of 30% based on the maximum force that can be applied before your tyres start to skid. If you increase this value, it will lead to the truck being able to descent (and be able to brake without skidding) roads with bigger gradients (steeper roads). By setting this value to 0.7 (70%) we are not going to the maximum limit of physics, but rather stay conservative in our assumptions of what is happening between the tyres and the road (remember the road in the mine is not uniform)
Retarder:
Use retarder speed limit: this should be ticked ON. It will prevent the truck from exceeding the speed from which the retarder is able to bring the truck to a stop on a descent.
Max use of retarder: 0.7
Imagine you have a truck driving down a ramp and you would need 30,000 kgf to bring the truck to a complete stop. Looking at the retarder curve below this would be physically (based on the specifications of the truck) possible when the truck drives around 32 km/h. If you now only want to use 70% of your available retarder force (safety margin), you will have to slow the truck down to ~23 km/h. This will now be the speed the truck will traverse the segment.
Figure 2: Typical retarder curve of a truck
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