The advantage of modular self-reconfigurable robot systems is their flexibility, but this advantage can only be realized if appropriate configurations (shapes) and behaviors (controlling programs) can be selected for a given task. In this paper, we present an integrated system for addressing high-level tasks with modular robots, and demonstrate that it is capable of accomplishing challenging, multi-part tasks in hardware experiments. The system consists of four tightly integrated components: (1) a high-level mission planner, (2) a large design library spanning a wide set of functionality, (3) a design and simulation tool for populating the library with new configurations and behaviors, and (4) modular robot hardware. This paper builds on earlier work by (in: Robotics: science and systems, 2016), extending the original system to include environmentally adaptive parametric behaviors, which integrate motion planners and feedback controllers with the system.
To take full advantage of the flexibility of a modular robot system, users must be able to create and verify new configurations and behaviors quickly. We present a design framework that facilitates rapid creation of new configurations and behaviors through composition of existing ones, and tools to verify configurations and behaviors as they are being created. New configurations are created by combining existing sub-configurations, for example combining four legs and a body to create a walking robot. Behaviors are associated with each configuration, so that when sub-configurations are composed, their associated behaviors are immediately available for composition as well. We introduce a new motion description language (Series-Parallel Action Graphs) that facilitates the rapid creation of complex behaviors by composition of simpler behaviors. We provide tools that automatically verify configurations and behaviors during the design process, allowing the user to identify problems early and iterate quickly. In addition to verification, users can evaluate their configurations and behaviors in a physics-based simulator.