FeatX: Controlled Robot Configuration with Flexible Feature Binding

Abstract

Robotic systems often need to be configured for different dynamic execution environments, hardware, or non-functional properties, such as energy consumption. Configuration options, a.k.a. features, can be used to enable, disable, and calibrate different parts of the system, ranging from whole subsystems over components to lines of code. While configuration mechanisms are abundant in robotics, they are limited in expressiveness, and the configuration files are often distributed over the codebase in different artifacts, challenging the consistent declaration and enforcement of dependencies. In addition, robotic systems require flexibility, since features need to be activated or changed at different times in the lifecycle of the system, which can cause intricate dependencies, especially when they depend on other static or dynamic features. To prevent misconfiguration and undefined behavior, such configuration spaces need to be properly declared and managed. We present FeatX, a model-based configuration technique. It uses and extends feature models, but accounts for the specific needs in robotics. Specifically, it allows declaring features, their dependencies, as well as the allowed binding times and binding modes, while the configurator enforces correct configuration and reconfiguration, considering intricate semantics of such models. We designed the syntax and semantics of the FeatX language and implemented them in the configurator. Our prototype is implemented for ROS2 with a command-line interface (ros2cli). We evaluated it upon realistic (re-)configuration scenarios.