Abstract: Robot systems are growing in importance and complexity. Ecosystems for robot software, such as the ROS, provide libraries of reusable software components that can be configured and composed into larger systems. To support compositionality, ROS uses late binding and architecture configuration via "launch files" that describe how to initialize the components in a system. However, late binding often leads to systems failing silently due to misconfiguration, for example by misrouting or dropping messages entirely.

In this paper we present ROSDiscover, which statically recovers the run-time architecture of ROS systems to find such architecture misconfiguration bugs. First, ROSDiscover constructs component level architectural models (ports, parameters) from source code. Second, architecture configuration files are analyzed to compose the system from these component models and derive the connections in the system. Finally, the reconstructed architecture is checked against architectural rules described in first-order logic to identify potential misconfigurations.

We present an evaluation of ROSDiscover on real world, off-the-shelf robotic systems, measuring the accuracy, effectiveness, and practicality of our approach. To that end, we collected the first data set of architecture configuration bugs in ROS from popular open-source systems and measure how effective our approach is for detecting configuration bugs in that set.

Abstract: While publish-subscribe systems have good engineering properties, they are difficult to reason about and to test. Model checking such systems is an attractive alternative. However, in practice coming up with an appropriate state model for a pub-sub system can be a difficult and error-prone task. In this paper we address this problem by describing a generic pub-sub model checking framework. The key feature of this framework is a reusable, parameterized state machine model that captures pub-sub runtime event management and dispatch policy. Generation of models for specific pub-sub systems is then handled by a translation tool that accepts as input a set of pub-sub component descriptions together with a set of pub-sub properties, and maps them into the framework where they can be checked using off-the-shelf model checking tools.

Abstract: While implicit invocation (publish-subscribe) systems have good engineering properties, they are difficult to reason about and to test. Model checking such systems is an attractive alternative. However, it is not clear what kinds of state models are best suited for this. In this paper we propose a structural approach, which factors the model checking problem into two parts: behavior specific to a particular implicit invocation system, and reusable runtime infrastructure that handles event-based communication and delivery policies. The reusable portion is itself structured so that alternative runtime mechanisms may be experimented with.