Feasibility of Large-scale Multi-AGV based Parcel Sortation Systems

Feasibility of Large-scale Multi-AGV based Parcel Sortation Systems

Heemskerk, Coen (TU Delft Mechanical, Maritime and Materials Engineering; TU Delft Transport Engineering and Logistics)

Pang, Y. (mentor)
Schott, D.L. (graduation committee)
Pruijn, J.F.J. (graduation committee)
Engelen, Frank (graduation committee)

Delft University of Technology

Mechanical Engineering

2020-01-21

This report presents insights in the feasibility of large-scale multi-AGV based parcel sortation systems. A simulation model is created to look at the influence of different aspects of such an Automated Guided Vehicles system. The model uses several design parameters and KPIs to determine the level of influence. Important aspects of this research are: the charging process of the AGVs, influence on pick-up points (parcel collection) and drop-off points (parcel destinations) and multiple types of AGVs on the same map. The AGVs will be modelled by an A* algorithm and uses grid-routing (either X or Y -movement at the same time). These kind of AGVs are controlled by a centralized robot control system. The task allocation the AGVs is done by a market- auction-based algorithm.

The first test set consists of a map of 1000m2 to operate at a throughput of at least 1600 parcels/hour. Here the placement of the pick-up points on all sides of the map is more efficient than on either one or two sides. Though the placement of two sides is further used as it is a more probable solution due to the use of large truck-bays and smaller vans in terms of a parcel sortation center. A linearity is found when adding more AGVs to the system. This is in between 5-50 AGVs for the 6 and 8 pick-up points with a ratio of 44.62 parcels/hour per additional AGV. Linearity is decreased due to more queueing and re-routing by congestions to 39.86 parcels/hour per additional AGV for 10 and 12 pick-up points. The charging process reduces the throughput with at least 7.54 % on a 16 hour simulation run. This is with a ratio of 5.71 AGVs per charging point. Using a higher ratio leads to AGVs shutting down due to low battery charge states.

Another test case is analysed with a 3000m2 area and the demand of achieving a throughput of at least 6000 parcels/hour. This is achieved by using 170 AGVs on a width of 75m and a length of 40m area. Even a small analysis is done in the use of 6 kg and 32 kg AGVs on the same working area. From which, a throughput of 1000 parcels/hour is gained by using 15 6 kg AGVs and 25 32 kg AGVs. The throughput is lower compared to using 40 32 kg AGVs: 1400 parcels/hour. Loss in efficiency could be considered compensated by the reduction in terms of AGV purchase costs.

This research has no optimization process, more potential is possible if an optimization is done with a more elaborate/complete (design) plan. This optimization could lead to more efficiency and more insights of an AGV parcel sortation system. Finally the possibilities of multiple types of AGVs on one map can be further investigated, with additional task allocation schemes or a more elaborate research in the pick-up points process.

AGVS
parcel sortation system
multi-type agv
agv charging

http://resolver.tudelft.nl/uuid:256986e8-a5f8-487e-bb82-6929254ad92a

2022-01-22

Student theses

master thesis

© 2020 Coen Heemskerk