Learning Policies of Sim-to-Real and LiDAR-to-mmWave Input Modalities for Collision Avoidance in Subterranean Environments

Abstract

Deep reinforcement learning (RL) have shown remarkable success on a variety of tasks to learn from mistakes. To learn collision-free policies for unmanned vehicles, deep RL has been trained with various data modalities including RGB, depth images, LiDAR point clouds without the use of classic map-localize-plan approaches. However, to operate in constrained passages under subterranean environments, existing methods are suffered from degraded sensing conditions, such as smoke and other obscurants, that impairs observations from camera and LiDAR. We propose sim-to-real, LiDAR-to-mmWave (millimeter wave radar) input modality for deep RL to overcome the challenges. We show that the trained models are generalized from simulation to real world, as well as LiDAR to mmWave transferring, despite the low spatial resolution and noisy inputs. Evaluations are carried out in underground environments, including a basement floor and large-scale testbeds in the Tunnel and Urban Circuits of the DARPA Subterranean Challenge. We provide an open dataset of real-world data for further comparisons.

Video

Datasets

All experiment data were stored in the form of rosbags.

click the link to download compressed bag file.

# Method Robot place Distance (m) Num of stop rosbag Duration (s) rviz
1 DRL-LiDAR husky2 EFB1 162.68 0 26GB 660
2 DRL-LiDAR husky1 EFB1 675.41 0 41GB 2523
3 DRL-LiDAR husky2 EFB1 867.59 1 93GB 3256
4 DRL-LiDAR husky2 EFB1 489.97 0 116GB 3302
5 DRL-LiDAR husky1 EFB1 531.35 0 93GB 2840
6 DRL-LiDAR husky1 EFB1 549.29 0 59GB 1913
7 DRL-LiDAR husky1 EFB1 166.16 0 36GB 1148
8 DRL-LiDAR husky2 EFB1 178.52 0 45GB 1160
9 DRL-mmWave husky1 EFB1 431.58 14 53GB 1852
10 DRL-LiDAR husky1 subt urban circuit - alpha course 277.53 0 136GB 3930