US Patent 10518770 Hierarchical motion planning for autonomous vehicles

An autonomous vehicle can implement a primary motion planner to continuously determine an first motion plan for the AV, and a secondary motion planner to continuously determine a backup motion plan for the AV. The secondary motion planner can comprise one or more cost metrics that act to diverge the backup motion plan from the first motion plan. A control system of the AV may then analyze a live sensor view generated by a sensor suite of the AV to operate acceleration, braking, and steering systems of the AV along sequential route trajectories selected between the first motion plan and the backup motion plan.