The Trajectory Bundle Method

The Trajectory Bundle Method

We present a unified framework for solving trajectory optimization problems in a derivative-free manner through the use of sequential convex programming. Traditionally, nonconvex optimization problems are solved by forming and solving a sequence of convex optimization problems, where the cost and constraint functions are approximated locally through Taylor series expansions. This presents a challenge for functions where differentiation is expensive or unavailable. In this work, we present a derivative-free approach to form these convex approximations by computing samples of the dynamics, cost, and constraint functions and letting the solver interpolate between them. Our framework includes sample-based trajectory optimization techniques like model-predictive path integral (MPPI) control as a special case and generalizes them to enable features like multiple shooting and general equality and inequality constraints that are traditionally associated with derivative-based sequential convex programming methods. The resulting framework is simple, flexible, and capable of solving a wide variety of practical motion planning and control problems.

Related Papers

2025
September
PDF The Trajectory Bundle Method: Unifying Sequential-Convex Programming and Sampling-Based Trajectory Optimization
Kevin Tracy, John Zhang, Jon Arrizabalaga, Stefan Schaal, Yuval Tassa, Tom Erez, and Zac Manchester
arXiv (In Review)

People

John Zhang
GPU Accelerated Optmization and Control through Contact
Jon Arrizabalaga
Optimization and Control
Zac Manchester
Associate Professor
Last updated: 2025-09-30