Non-functional requirements and their impact on AGV based systems

Abstract

The use of Automated Guided Vehicles (AGVs) has grown rapidly in recent years. The global market was valued at 3.81 billion USD in 2021 and is expected to grow at a compound annual rate of 10.2% between 2022 and 2030. The efficiency of these systems in warehouses and production facilities are impacted by the choice of nonfunctional requirements (NFRs).

This study is based on a mixed-method approach to assess the impact that these NFRs have on system throughput, and whether the results differentiate based on the layout and the fleet size of the system. An interview study and a literature review were conducted to ascertain what the most essential requirements are for those systems. The results show that requirements regarding safety and robustness are the most imperative for the industry.

A simulation tool was created during the study which utilizes a modification of the A∗ algorithm, based on both space and time. The tool was used to create two different layouts, used to represent different warehouse scenarios. A smaller layout (75m x 75m) and a larger layout (150m x 150m) was created. The identified NFRs were then independently varied and compared to a base case.

The results show that the identified NFRs have a profound effect on system throughput. It was established that the impact of the different NFRs generally are amplified in the smaller layout. Decreasing the fleet size leads to a larger, relative decrease in throughput for the smaller layout due to increased congestion. Increasing the fleet size has diminishing returns until the system is at max capacity and a further increase in the number of agents only leads to more congestion, lowering the throughput.