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arXiv · 2002.01591

Reachable Sets for Safe, Real-Time Manipulator Trajectory Design

Patrick Holmes·Shreyas Kousik·Bohao Zhang·Daphna Raz·Corina Barbalata·Matthew Johnson-Roberson·Ram Vasudevan
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Abstract

For robotic arms to operate in arbitrary environments, especially near people, it is critical to certify the safety of their motion planning algorithms. However, there is often a trade-off between safety and real-time performance; one can either carefully design safe plans, or rapidly generate potentially-unsafe plans. This work presents a receding-horizon, real-time trajectory planner with safety guarantees, called ARMTD (Autonomous Reachability-based Manipulator Trajectory Design). The method first computes (offline) a reachable set of parameterized trajectories for each joint of an arm. Each trajectory includes a fail-safe maneuver (braking to a stop). At runtime, in each receding-horizon planning iteration, ARMTD constructs a parameterized reachable set of the full arm in workspace and intersects it with obstacles to generate sub-differentiable, provably-conservative collision-avoidance constraints on the trajectory parameters. ARMTD then performs trajectory optimization over the parameters, subject to these constraints. On a 6 degree-of-freedom arm, ARMTD outperforms CHOMP in simulation, never crashes, and completes a variety of real-time planning tasks on hardware.

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Patrick Holmes, Shreyas Kousik, Bohao Zhang, Daphna Raz, Corina Barbalata, Matthew Johnson-Roberson, Ram Vasudevan. 2020-02-05. Reachable Sets for Safe, Real-Time Manipulator Trajectory Design. https://arxiv.org/abs/2002.01591

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