Learning Based Optimal Control for Nonlinear Robotic Systems: Integrating Dynamic Programming, Analytical Rigid Body Models, and Diffusion Policies
Abstract
The convergence of optimal control theory, robotics, and machine learning has produced a new generation of methodologies capable of addressing high dimensional nonlinear dynamical systems. Classical dynamic programming, rooted in the foundational work of Bellman, provides a principled framework for sequential decision making but suffers from the curse of dimensionality. Trajectory optimization methods such as Differential Dynamic Programming and modern numerical techniques enable efficient local optimization but remain sensitive to initialization and model inaccuracies. Concurrently, advances in rigid body dynamics libraries, including the development of analytical derivatives and fast forward and inverse dynamics algorithms, have significantly reduced computational overhead in robot modeling. In parallel, machine learning has introduced nonparametric representations, Gaussian process based dynamic programming, deep neural approximations for stochastic control, and diffusion based policy learning frameworks that challenge conventional paradigms.
This article presents a comprehensive theoretical integration of these traditions. Drawing strictly from the referenced works, it synthesizes trajectory based nonparametric value representation, random state sampling in dynamic programming, Gaussian process control, analytical rigid body dynamics, machine learning assisted model predictive control, diffusion policy learning, and neural approximations of Pontryagin based optimality conditions. The research develops a unified perspective in which analytical physics based modeling and data driven learning are not competing alternatives but complementary layers within a hierarchical optimal control architecture.
The methodology elaborates a conceptual framework combining exact rigid body derivatives from the Pinocchio library with learning based policy representations trained via stochastic optimal control matching and diffusion models. A detailed theoretical comparison between classical feedback control design and modern deep learning approximations is conducted. The results section provides an extensive descriptive analysis of how these combined approaches improve scalability, generalization, and closed loop robustness in robotic manipulators and aerial platforms such as micro quadrotors and lightweight robotic arms.
The discussion critically examines computational complexity, generalization across domains, and the epistemological implications of replacing explicit dynamic programming recursions with learned approximations. The article concludes by outlining a path toward interpretable, scalable, and computationally efficient learning based optimal control for complex robotic systems.