Autonomous robots are increasingly deployed for information-gathering tasks in environments that vary across space and time. Planning informative and safe trajectories in such settings is challeng- ing because information decays when regions are not revisited. Most existing planners model infor- mation as static or uniformly decaying, ignoring environments where the decay rate varies spatially; those that model non-uniform decay often overlook how it evolves along the robot’s motion, and almost all treat safety as a soft penalty. In this paper, we address these challenges. We model uncer- tainty in the environment using clarity, a normalized representation of differential entropy from our earlier work that captures how information improves through new measurements and decays over time when regions are not revisited. Building on this, we present Stein Variational Clarity-Aware Informative Planning, a framework that embeds clarity dynamics within trajectory optimization and enforces safety through a low-level filtering mechanism based on our earlier gatekeeper frame- work for safety verification. The planner performs Bayesian inference-based learning via Stein variational inference, refining a distribution over informative trajectories while filtering each nom- inal Stein informative trajectory to ensure safety. Simulations across environments with varying decay rates and obstacles demonstrate consistent safety and reduced information deficits.
We quantify uncertainty using clarity, which evolves over time as the robot gathers measurements and decays when regions are not revisited. Instead of precomputing a static target distribution, we directly couple the robot's motion with the clarity dynamics, enabling the planner to reason about spatiotemporal information evolution. To generate informative motion, we maintain a distribution of candidate trajectories using Stein variational inference, allowing the planner to explore multiple informative strategies in parallel. For safety, each trajectory is evaluated using a gatekeeper safety filter, which certifies whether its execution remains within the safe set and has a valid backup. The robot executes only the informative and safety-verified trajectory, ensuring reliable and adaptive exploration in spatiotemporally evolving environments.
We demonstrate the framework in action on a real quadrotor platform operating in an environment with obstacles. The experiments showcase the planner's ability to generate informative trajectories that adapt to spatiotemporal information evolution while maintaining safety guarantees through the gatekeeper filter.
Simulation results demonstrating the performance across various environments with different decay rates and obstacle configurations.
Target Clarity Field
Decay Field
Target Clarity Field
Decay Field
Target Clarity Field
Decay Field
Target Clarity Field
Decay Field
Target Clarity Field
Decay Field
Target Clarity Field
Decay Field
Target Clarity Field
Decay Field
Target Clarity Field
Decay Field
Target Clarity Field
Decay Field
Target Clarity Field
Decay Field
Target Clarity Field
Decay Field
Target Clarity Field
Decay Field
Target Clarity Field
Decay Field
Target Clarity Field
Decay Field
Target Clarity Field
Decay Field
Target Clarity Field
Decay Field
Target Clarity Field
Decay Field
Target Clarity Field
Decay Field
Target Clarity Field
Decay Field
Target Clarity Field
Decay Field