Research project

Safe Learning for Legged Robots

Walking policies must handle changing contacts, terrain, and disturbances. We combine structured control and reduced-order models with learning, then evaluate the resulting behavior in simulation and robot experiments.

Digit simulation used to demonstrate model-informed safe reinforcement learning.
Model-informed safe learning in Digit simulation · October 2026 lab video.
  1. Structure policies with walking models
  2. Learn control behavior in simulation
  3. Evaluate performance and safety conditions

The problem

Learning a locomotion policy must address changing contact dynamics, disturbances, and the gap between training and robot experiments. Safety properties also depend on the model and conditions under which they are derived.

Our approach

We combine structured control policies and reduced-order walking models with reinforcement learning. Work includes cascade motion policies, compact terrain representations, and model-informed step-to-step prediction for safe learning.

Results and experimental setting

  • Learned walking on hardware: The cascade-policy work includes Digit walking experiments, with a linked lab demonstration.
  • Terrain-aware representations: The TCST 2026 journal paper evaluates locomotion in high-fidelity simulation and reports preliminary hardware sensor comparisons.
  • Model-informed safe learning: The 2026 study evaluates full-order Digit in MuJoCo, using step-to-step predictions to inform policy learning and runtime foot-placement filtering.

Safety conditions: The safe-learning certificate applies to the reduced-order model under the paper’s assumptions. Each study identifies its own training, simulation, and hardware evaluation conditions.

Papers and demonstrations

Watch model-informed safe learning and the earlier learned Digit walking experiments.

Explore the original project-goals diagram
Original project-goals diagram connecting inverse reinforcement learning, navigation, stepping, gait policies, and proposed robot transfer.
Illustration of proposed project goals.
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