The Robotics Service Bus (RSB) is a message-oriented, event-driven middleware aiming at scalable integration of robotics systems in diverse environments. Being fundamentally a bus architecture, RSB structures heterogeneous systems of service providers and consumers using broadcast communication over a hierarchy of logically unified channels instead of a large number of point-to-point connections. Nevertheless RSB comes with a collection of communication patterns and other tools for structuring communication, but does not require a particular functional or decomposition style.

RSB is implemented as a flexible, lightweight toolkit. Based on previous experiences, the design and implementation try to avoid centralization and complicated dependency structures. Instead, functionality is organized in layers with minimal, clearly stated dependencies. The core library merely supplies the abstractions and machinery for building communication systems subject to varying requirements. This core is implemented in multiple programming languages with implementations trying to be in the spirit of the respective language as much as possible. As a result, RSB is not tied to a particular network transport, serialization mechanism or programming language. In addition, much effort is put into systematic testing and continuous integration.

These conceptual and implementation properties hopefully allow RSB to scale across a wider range of diverse functional requirements, heterogeneous hardware platforms and varying reliability and timing requirements than other robotics middlewares. Additionally, RSB‘s open architecture and project structure and lightweight implementation enable its use with small entry barriers and little framework lock-in.



An event is the basic unit of exchanged data in RSB. Hence, all information required to fully specify and trace the condition it represents need to be present in the event. To fulfill these requirements, our event model consists of the following components:


The payload of an event is a user-defined object of the respective programming language which contains the major information specifying the condition the event represents.

It can be of an arbitrary domain type which reduces the framework lock-in by means of an early transition from framework types to domain objects for technical realization.

A unique ID for each event in an RSB-based system to make events addressable and foster traceability.
Meta Data

Each event is supplemented by meta data.

It consist of the event sender’s ID and several timestamps that

  • specify timing information relevant to the condition represented by the event (user-extensible)
  • make the the processing of the event within RSB traceable.

Besides these framework-supplied items, a key-value store for string-based additional meta data items is available for the client and user-defined timestamps can be added.

Causal Vector
This vector allows to represent the causing events of a given event, as proposed in [Luckham2001PEI]. It facilitates automatic system analysis and debugging.
Destination Scope
Specifies the recipients of the event notification by restricting the visibility of event notifications [Muehl2006-DEB].




See also

Specification for handling of URI in RSB.

URIs or URLs are used in the following situations

  • Specifying how to connect to the bus (i.e. specifying a scope and transport configuration)
  • Naming a thing on the bus