Sim-to-Real Transfer for Muscle-Actuated Robots via Generalized Actuator Networks

Fuente: arXiv
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Auteurs principaux: Schneider, Jan, Mahajan, Mridul, Chen, Le, Guist, Simon, Schölkopf, Bernhard, Posner, Ingmar, Büchler, Dieter
Format: Preprint
Publié: 2026
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author Schneider, Jan
Mahajan, Mridul
Chen, Le
Guist, Simon
Schölkopf, Bernhard
Posner, Ingmar
Büchler, Dieter
author_facet Schneider, Jan
Mahajan, Mridul
Chen, Le
Guist, Simon
Schölkopf, Bernhard
Posner, Ingmar
Büchler, Dieter
contents Tendon drives paired with soft muscle actuation enable faster and safer robots while potentially accelerating skill acquisition. Still, these systems are rarely used in practice due to inherent nonlinearities, friction, and hysteresis, which complicate modeling and control. So far, these challenges have hindered policy transfer from simulation to real systems. To bridge this gap, we propose a sim-to-real pipeline that learns a neural network model of this complex actuation and leverages established rigid body simulation for the arm dynamics and interactions with the environment. Our method, called Generalized Actuator Network (GenAN), enables actuation model identification across a wide range of robots by learning directly from joint position trajectories rather than requiring torque sensors. Using GenAN on PAMY2, a tendon-driven robot powered by pneumatic artificial muscles, we successfully deploy dynamic but precise goal-reaching, ball-in-a-cup, and table tennis policies, trained entirely in simulation. To the best of our knowledge, this result constitutes the first successful sim-to-real transfer for a four-degrees-of-freedom muscle-actuated robot arm.
format Preprint
id arxiv_https___arxiv_org_abs_2604_09487
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Sim-to-Real Transfer for Muscle-Actuated Robots via Generalized Actuator Networks
Schneider, Jan
Mahajan, Mridul
Chen, Le
Guist, Simon
Schölkopf, Bernhard
Posner, Ingmar
Büchler, Dieter
Robotics
Machine Learning
Tendon drives paired with soft muscle actuation enable faster and safer robots while potentially accelerating skill acquisition. Still, these systems are rarely used in practice due to inherent nonlinearities, friction, and hysteresis, which complicate modeling and control. So far, these challenges have hindered policy transfer from simulation to real systems. To bridge this gap, we propose a sim-to-real pipeline that learns a neural network model of this complex actuation and leverages established rigid body simulation for the arm dynamics and interactions with the environment. Our method, called Generalized Actuator Network (GenAN), enables actuation model identification across a wide range of robots by learning directly from joint position trajectories rather than requiring torque sensors. Using GenAN on PAMY2, a tendon-driven robot powered by pneumatic artificial muscles, we successfully deploy dynamic but precise goal-reaching, ball-in-a-cup, and table tennis policies, trained entirely in simulation. To the best of our knowledge, this result constitutes the first successful sim-to-real transfer for a four-degrees-of-freedom muscle-actuated robot arm.
title Sim-to-Real Transfer for Muscle-Actuated Robots via Generalized Actuator Networks
topic Robotics
Machine Learning
url https://arxiv.org/abs/2604.09487