We present a new application of model checking which achieves real-time multi-step planning and obstacle avoidance on a real autonomous robot. We have developed a small, purpose-built model checking algorithm which generates plans in situ based on "core" knowledge and attention as found in biological agents. This is achieved in real-time using no pre-computed data on a low-powered device. Our approach is based on chaining temporary control systems which are spawned to counteract disturbances in the local environment that disrupt an autonomous agent from its preferred action (or resting state). A novel discretization of 2D LiDAR data sensitive to bounded variations in the local environment is used. Multi-step planning using model checking by forward depth-first search is applied to cul-de-sac and playground scenarios. Both empirical results and informal proofs of two fundamental properties of our approach demonstrate that model checking can be used to create efficient multi-step plans for local obstacle avoidance, improving on the performance of a reactive agent which can only plan one step. Our approach is an instructional case study for the development of safe, reliable and explainable planning in the context of autonomous vehicles.

In their paper Model Checking for Closed-Loop Robot Reactive Planning, Christopher Chandler, Bernd Porr, Alice Miller and Giulia Lafratta show how model checking can be used to create multi-step plans for a differential drive wheeled robot so that it can avoid immediate danger. In this interview, Christopher tells us about model checking and how it is used in the context of autonomous robotic systems. We also find out more about the team's approach and the implementation of their method. Two major barriers for widespread adoption of autonomous driving are safety and public trust. While trust is notoriously difficult to define, it is generally accepted that transparency is essential for human interactions with safety-critical autonomous systems.