Warm-Starting Collision-Free Model Predictive Control With Object-Centric Diffusion

TL;DR

This paper introduces a hybrid approach combining diffusion models, object-centric scene representations, and collision-aware MPC to enable fast, reliable collision-free motion planning in cluttered environments, demonstrated on benchmarks and real robots.

Contribution

It presents a novel method that integrates diffusion-based warm-starting with object-centric scene encoding and collision-aware MPC for efficient motion planning.

Findings

Higher success rates in benchmark tasks

Lower latency compared to sampling-based planners

Reliable and safe execution on real robot

Abstract

Acting in cluttered environments requires predicting and avoiding collisions while still achieving precise control. Conventional optimization-based controllers can enforce physical constraints, but they struggle to produce feasible solutions quickly when many obstacles are present. Diffusion models can generate diverse trajectories around obstacles, yet prior approaches lacked a general and efficient way to condition them on scene structure. In this paper, we show that combining diffusion-based warm-starting conditioned with a latent object-centric representation of the scene and with a collision-aware model predictive controller (MPC) yields reliable and efficient motion generation under strict time limits. Our approach conditions a diffusion transformer on the system state, task, and surroundings, using an object-centric slot attention mechanism to provide a compact obstacle representation suitable for control. The sampled trajectories are refined by an optimal control problem that enforces rigid-body dynamics and signed-distance collision constraints, producing feasible motions in real time. On benchmark tasks, this hybrid method achieved markedly higher success rates and lower latency than sampling-based planners or either component alone. Real-robot experiments with a torque-controlled Panda confirm reliable and safe execution with MPC.