Whole-body End-Effector Pose Tracking

Fuente: arXiv
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Main Authors: Portela, Tifanny, Cramariuc, Andrei, Mittal, Mayank, Hutter, Marco
Format: Preprint
Published: 2024
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author Portela, Tifanny
Cramariuc, Andrei
Mittal, Mayank
Hutter, Marco
author_facet Portela, Tifanny
Cramariuc, Andrei
Mittal, Mayank
Hutter, Marco
contents Combining manipulation with the mobility of legged robots is essential for a wide range of robotic applications. However, integrating an arm with a mobile base significantly increases the system's complexity, making precise end-effector control challenging. Existing model-based approaches are often constrained by their modeling assumptions, leading to limited robustness. Meanwhile, recent Reinforcement Learning (RL) implementations restrict the arm's workspace to be in front of the robot or track only the position to obtain decent tracking accuracy. In this work, we address these limitations by introducing a whole-body RL formulation for end-effector pose tracking in a large workspace on rough, unstructured terrains. Our proposed method involves a terrain-aware sampling strategy for the robot's initial configuration and end-effector pose commands, as well as a game-based curriculum to extend the robot's operating range. We validate our approach on the ANYmal quadrupedal robot with a six DoF robotic arm. Through our experiments, we show that the learned controller achieves precise command tracking over a large workspace and adapts across varying terrains such as stairs and slopes. On deployment, it achieves a pose-tracking error of 2.64 cm and 3.64 degrees, outperforming existing competitive baselines.
format Preprint
id arxiv_https___arxiv_org_abs_2409_16048
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Whole-body End-Effector Pose Tracking
Portela, Tifanny
Cramariuc, Andrei
Mittal, Mayank
Hutter, Marco
Robotics
Artificial Intelligence
Machine Learning
Systems and Control
Combining manipulation with the mobility of legged robots is essential for a wide range of robotic applications. However, integrating an arm with a mobile base significantly increases the system's complexity, making precise end-effector control challenging. Existing model-based approaches are often constrained by their modeling assumptions, leading to limited robustness. Meanwhile, recent Reinforcement Learning (RL) implementations restrict the arm's workspace to be in front of the robot or track only the position to obtain decent tracking accuracy. In this work, we address these limitations by introducing a whole-body RL formulation for end-effector pose tracking in a large workspace on rough, unstructured terrains. Our proposed method involves a terrain-aware sampling strategy for the robot's initial configuration and end-effector pose commands, as well as a game-based curriculum to extend the robot's operating range. We validate our approach on the ANYmal quadrupedal robot with a six DoF robotic arm. Through our experiments, we show that the learned controller achieves precise command tracking over a large workspace and adapts across varying terrains such as stairs and slopes. On deployment, it achieves a pose-tracking error of 2.64 cm and 3.64 degrees, outperforming existing competitive baselines.
title Whole-body End-Effector Pose Tracking
topic Robotics
Artificial Intelligence
Machine Learning
Systems and Control
url https://arxiv.org/abs/2409.16048