Efficient Multi-Robot Motion Planning with Precomputed Translation-Invariant Edge Bundles

Himanshu Gupta, Paul Motter, Aritra Chakrabarty, Rishabh Sodani, Srikrishna Bangalore Raghu,
Alessandro Roncone, Bradley Hayes, Zachary Sunberg
University of Colorado Boulder

Abstract

Solving multi-robot motion planning (MRMP) requires generating collision-free kinodynamically feasible trajectories for multiple interacting robots. We introduce Kinodynamic Translation-Invariant Edge Bundles or KiTE-Extend, a planner-agnostic action selection mechanism for sampling-based kinodynamic motion planning. KiTE-Extend uses a library of trajectory segments computed offline to guide action selection during online planning, improving the ability of existing planners to identify feasible motion segments without altering state propagation, collision checking, or cost evaluation, and without changing their theoretical guarantees. While KiTE-Extend can modestly improve single-agent planners, its benefits are most clear in the multi-agent setting, where it is able to explore more effectively and significantly improve planning through the dense spatiotemporal constraints introduced by robot-robot interaction. Through experiments on multiple kinodynamic systems and environments, we show that KiTE-Extend reduces planning time and improves scalability across the three most common MRMP paradigms: centralized, prioritized, and conflict-based.

KiTE-Extend ranks edge-bundle candidates and skips invalid motions near a static obstacle KiTE-Extend selects a safe edge-bundle candidate under dynamic agent collision constraints

Fig. 2 from the paper. KiTE-Extend ranks precomputed dynamically feasible trajectory segments by endpoint distance to the sampled state and tries them in order. Left: invalid edges are skipped when they collide with static obstacles. Right: under agent collision constraints, the same mechanism selects a safe alternative, including low-velocity or wait-like motions when needed.

Key idea

Turn local expansion into retrieval and ranking.

Sampling-based kinodynamic planners spend much of their time trying local control rollouts that collide, violate constraints, or make little progress. KiTE-Extend keeps the planner unchanged, but replaces naive random action selection with reusable candidate motions computed offline.

1
Precompute feasible edges Generate short dynamically feasible trajectory segments once per robot model from translation-normalized start states.
2
Retrieve local candidates At each tree expansion, query edge bundles whose translation-invariant state components match the current node.
3
Rank, propagate, validate Try candidates that make progress toward the sampled target, re-propagate them online, and fall back to random expansion when needed.

At a glance

What KiTE-Extend contributes

  • Planner-agnostic action selection. KiTE-Extend plugs into sampling-based kinodynamic planners at the local expansion step.
  • Offline reuse without discretizing the search space. Edge bundles guide expansion, but planning remains continuous and sampling-based.
  • Guarantee-preserving fallback. Candidate edges are validated online, and random expansion remains available to preserve exploration.
  • Multi-robot impact. The same primitive improves centralized RRT, prioritized RRT, and conflict-based search across several robot models.

Results summary

Faster planning, better scalability, shorter trajectories.

Experiments use 100 trials per setting with a 300 second runtime budget, comparing baseline planners against their KiTE-Extend variants for unicycle, second-order car, and double-integrator systems.

4.2x Mean computation-time reduction for pRRT+KiTE across representative settings with comparable success rates.
40-60% Lower total path duration for cRRT+KiTE on trials where both baseline and KiTE variants succeed.
20-30% Lower total path duration for pRRT+KiTE and KCBS+KiTE in evaluated settings.
5-10 s Approximate one-time edge-bundle generation cost per kinodynamic system, excluded from online runtimes.
KiTE-Extend is especially useful in MRMP because robot-robot constraints make repeated low-level expansion expensive. KCBS benefits strongly because every high-level conflict update can trigger low-level replanning.

Where it helps

One expansion primitive, three MRMP paradigms.

Centralized RRT KiTE-Extend mainly improves feasibility and scalability by making productive joint-state expansions more likely as team size grows.
Prioritized RRT KiTE-Extend reduces per-agent planning time and path duration, while priority ordering still determines some hard failures.
KCBS KiTE-Extend accelerates repeated low-level replanning and naturally proposes wait-like or recovery motions under spatiotemporal constraints.

Video comparisons

Baseline planners vs. KiTE-Extend variants.

Each row compares the baseline planner with the corresponding KiTE-Extend variant for the same environment. All videos autoplay muted at 2x speed.

pRRT comparison: 30 robots, Swap environment

pRRT baseline
pRRT + KiTE-Extend

KCBS comparison: 18 robots, Small Cluttered environment

KCBS baseline
KCBS + KiTE-Extend

KCBS comparison: 30 robots, Large Cluttered environment

KCBS baseline
KCBS + KiTE-Extend

KCBS comparison: 30 robots, Large Cluttered 3D environment

KCBS baseline
KCBS + KiTE-Extend

BibTeX

@article{gupta2026kiteextend,
  title={Efficient Multi-Robot Motion Planning with Precomputed Translation-Invariant Edge Bundles},
  author={Gupta, Himanshu and Motter, Paul and Chakrabarty, Aritra and Sodani, Rishabh and Raghu, Srikrishna Bangalore and Roncone, Alessandro and Hayes, Bradley and Sunberg, Zachary},
  year={2026}
}

Paper

Read the full paper