Simulation of an Electric Quarry with Automated Transporter Scheduling

Sammanfattning: An electric site project is being developed by Volvo Construction Equipment with the goal to transform the quarry and aggregate industry by reducing carbon emissions by up to 95 % and total ownership cost up to 25 %. The goal is achieved by using electrical autonomous vehicles as the work force. In an effort to reduce lead times, from design to reality, the objective of this thesis was to develop a logical architecture of a quarry using the Systems Modelling Language. The logical model contains all the essential elements existent in a quarry and describes core behavior to reflect the requirements needed in an electric site. The value of the logical model lies in its ability to aid the development process, complementing it with an executable simulation further show-cases that value. The simulation was used to analyze the performance of the electrical autonomous transporter HX02 that is instructed by an algorithm for optimal routing and scheduling. The algorithm incorporates traffic to reduce congestion at vertices with high level of activity. Its robustness is evaluated by varying the number of transporters and the weight on the traffic cost in the cost function. It was found that applying the traffic cost helped reduce the congestion significantly and increased production, but at the cost of more battery usage. The effect of incorporating traffic was most noticeable when there were more than 10 transporters operational. But when the weight on the traffic cost was too large, the production declined instead. The observed time complexity of the algorithm was O(n2), which was feasible due to a small input size n.