HarmoniKt: a Unifying Middleware for Heterogeneous Robot Fleets

In recent years, companies have increasingly invested in Industry 4.0 research to automate repetitive tasks or activities that may be harmful to humans. For instance, large-scale warehouses, such as those operated by Amazon, rely heavily on mobile robots to streamline logistics operations and ensure worker safety. At the same time, robot manufacturers are releasing more reliable platforms with advanced capabilities, making them suitable for complex industrial tasks. Despite this growing interest and technological progress, significant challenges remain. A key and non-trivial issue lies in the integration of heterogeneous robot fleets: each vendor typically employs proprietary technologies and interfaces, which hinders interoperability and limits the potential of multi-brand deployments.In this work, we introduce HARMONIKT, an extensible middleware that addresses this challenge by introducing an abstraction layer and providing a unified REST API for the control and management of heterogeneous robots. Our solution has been validated in a physical industrial-like environment using a mixed fleet of Boston Dynamics Spot and Mobile Industrial Robots (MiR). Furthermore, we present a comparative analysis showing that the access latency introduced by our middleware is not significantly higher than that of direct robot access, demonstrating the feasibility of unified robot management without compromising performance.