Gradient-Based Trajectory Optimization With Learned Dynamics

Trajectory optimization methods have achieved an exceptional level of performance on real-world robots in recent years. These methods heavily rely on accurate analytical models of the dynamics, yet some aspects of the physical world can only be captured to a limited extent. An alternative approach is to leverage machine learning techniques to learn a differentiable dynamics model of the system from data. In this work, we use trajectory optimization and model learning for performing highly dynamic and complex tasks with robotic systems in absence of accurate analytical models of the dynamics. We show that a neural network can model highly nonlinear behaviors accurately for large time horizons, from data collected in only 25 minutes of interactions on two distinct robots: (i) the Boston Dynamics Spot and an (ii) RC car. Furthermore, we use the gradients of the neural network to perform gradient-based trajectory optimization. In our hardware experiments, we demonstrate that our learned model can represent complex dynamics for both the Spot and Radio-controlled (RC) car, and gives good performance in combination with trajectory optimization methods.

Authors

• Bhavya Sukhija
• Nathanael Köhler
• Miguel Zamora
• Simon Zimmermann
• Sebastian Curi
• Andreas Krause 0001
• Stelian Coros

Keywords

• Analytical models
• Neural networks
• Machine learning
• Data models
• Hardware
• Nonlinear dynamical systems
• Automobiles
• Gradient-based Optimization
• Trajectory Optimization
• Neural Network
• Accuracy Of Model
• Learning Models
• Dynamic Model
• Robotic System
• Complex Systems
• System Dynamics
• Dynamical
• Artificial Neural Network
• Optimal Control
• First-principles
• Recurrent Neural Network
• Multilayer Perceptron
• Goal Of This Work
• Model Predictive Control
• Mobile Robot
• Chain Rule
• Gait Cycle
• Low-level Control
• Robot Dynamics
• Trajectory Optimization Problem
• State Transition Function
• Unknown Environment
• Horizon Length
• Unknown Dynamics
• Feed-forward Network
• Black Box
• Operating Conditions