LiDAR-Based Online Control Barrier Function Synthesis for Safe Navigation in Unknown Environments

This letter presents a novel extension of the control barrier function (CBF) as the low-level safety controller for autonomous mobile robots navigating in unknown environments. The main challenges of implementing CBF in real-world situations arise from the absence of a model or the lack of an exact one for the environment. Additionally, online learning is needed for the robot to maneuver in an unknown environment which leads to dealing with the sampled data set size, memory, and computational complexity. We address these challenges by designing an online non-parametric LiDAR-based safety function using the Gaussian process (GP). It is both efficient in data size and eliminates the requirement to store previous data. Then, a CBF is synthesized using the proposed safety function to rectify the safe control input. The effectiveness of the LiDAR-based CBF synthesis for navigation in unknown environments was validated by conducting experiments on unicycle-type robots.