Behavior cloning (BC) is a widely used approach in imitation learning where a robot learns a control policy by observing an expert supervisor. However the learned policy can make errors and might lead to safety violations which limits their utility in safety-critical robotics applications. While prior works have tried improving a BC policy via additional real or synthetic action labels adversarial training or runtime filtering none of them explicitly focus on reducing the BC policy's safety violations during training time. We propose SAFE-GIL a design-time method to learn safety-aware behavior cloning policies. SAFE-GIL deliberately injects adversarial disturbance in the system during data collection to guide the expert towards safety-critical states. This disturbance injection simulates potential policy errors that the system might encounter during the test time. By ensuring that training more closely replicates expert behavior in safety-critical states our approach results in safer policies despite policy errors during the test time. We further develop a reachability-based method to compute this adversarial disturbance. We compare SAFE-GIL with various behavior cloning techniques and online safety-filtering methods in three domains autonomous ground navigation aircraft taxiing and aerial navigation on a quadrotor testbed. Our method demonstrates a significant reduction in safety failures particularly in low data regimes where the likelihood of learning errors and therefore safety violations is higher. See our website here: https://y-u-c.github.io/safegil/.

Robot swarms can be tasked with a variety of automated sensing and inspection applications in aerial, aquatic, and surface environments. In this paper, we study a simplified two-outcome surface inspection task. We task a group of robots to inspect and collectively classify a 2D surface section based on a binary pattern projected on the surface. We use a decentralized Bayesian decision-making algorithm and deploy a swarm of 3-cm sized wheeled robots to inspect a randomized black and white tiled surface section of size 1m×1m in simulation. We first describe the model parameters that characterize our simulated environment, the robot swarm, and the inspection algorithm. We then employ a noise-resistant heuristic optimization scheme based on the Particle Swarm Optimization (PSO) using a fitness evaluation that combines the swarm’s classification decision accuracy and decision time. We use our fitness measure definition to asses the optimized parameters through 100 randomized simulations that vary surface pattern and initial robot poses. The optimized algorithm parameters show up to 55% improvement in median of fitness evaluations against an empirically chosen parameter set.