Energy-Efficient Motion Planner for Legged Robots

Fuente: arXiv
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Main Authors: Schperberg, Alexander, Menner, Marcel, Di Cairano, Stefano
Format: Preprint
Published: 2025
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author Schperberg, Alexander
Menner, Marcel
Di Cairano, Stefano
author_facet Schperberg, Alexander
Menner, Marcel
Di Cairano, Stefano
contents We propose an online motion planner for legged robot locomotion with the primary objective of achieving energy efficiency. The conceptual idea is to leverage a placement set of footstep positions based on the robot's body position to determine when and how to execute steps. In particular, the proposed planner uses virtual placement sets beneath the hip joints of the legs and executes a step when the foot is outside of such placement set. Furthermore, we propose a parameter design framework that considers both energy-efficiency and robustness measures to optimize the gait by changing the shape of the placement set along with other parameters, such as step height and swing time, as a function of walking speed. We show that the planner produces trajectories that have a low Cost of Transport (CoT) and high robustness measure, and evaluate our approach against model-free Reinforcement Learning (RL) and motion imitation using biological dog motion priors as the reference. Overall, within low to medium velocity range, we show a 50.4% improvement in CoT and improved robustness over model-free RL, our best performing baseline. Finally, we show ability to handle slippery surfaces, gait transitions, and disturbances in simulation and hardware with the Unitree A1 robot.
format Preprint
id arxiv_https___arxiv_org_abs_2503_06050
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Energy-Efficient Motion Planner for Legged Robots
Schperberg, Alexander
Menner, Marcel
Di Cairano, Stefano
Robotics
Systems and Control
We propose an online motion planner for legged robot locomotion with the primary objective of achieving energy efficiency. The conceptual idea is to leverage a placement set of footstep positions based on the robot's body position to determine when and how to execute steps. In particular, the proposed planner uses virtual placement sets beneath the hip joints of the legs and executes a step when the foot is outside of such placement set. Furthermore, we propose a parameter design framework that considers both energy-efficiency and robustness measures to optimize the gait by changing the shape of the placement set along with other parameters, such as step height and swing time, as a function of walking speed. We show that the planner produces trajectories that have a low Cost of Transport (CoT) and high robustness measure, and evaluate our approach against model-free Reinforcement Learning (RL) and motion imitation using biological dog motion priors as the reference. Overall, within low to medium velocity range, we show a 50.4% improvement in CoT and improved robustness over model-free RL, our best performing baseline. Finally, we show ability to handle slippery surfaces, gait transitions, and disturbances in simulation and hardware with the Unitree A1 robot.
title Energy-Efficient Motion Planner for Legged Robots
topic Robotics
Systems and Control
url https://arxiv.org/abs/2503.06050