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Soft robot shape estimation with IMUs leveraging PCC kinematics for drift filtering

Stella, F. (author), Della Santina, C. (author), Hughes, Josie (author)

The control possibilities for soft robots have long been hindered by the need for reliable methods to estimate their configuration. Inertial measurement units (IMUs) can solve this challenge, but they are affected by well-known drift issues. This letter proposes a method to eliminate this limitation by leveraging the Piecewise Constant...

journal article 2024

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Neural Autoencoder-Based Structure-Preserving Model Order Reduction and Control Design for High-Dimensional Physical Systems

Lepri, M. (author), Bacciu, Davide (author), Della Santina, C. (author)

This letter concerns control-oriented and structure-preserving learning of low-dimensional approximations of high-dimensional physical systems, with a focus on mechanical systems. We investigate the integration of neural autoencoders in model order reduction, while at the same time preserving Hamiltonian or Lagrangian structures. We focus on...

journal article 2024

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Input Decoupling of Lagrangian Systems via Coordinate Transformation: General Characterization and its Application to Soft Robotics

Pustina, P. (author), Della Santina, C. (author), Boyer, Frederic (author), De Luca, Alessandro (author), Renda, Federico (author)

Suitable representations of dynamical systems can simplify their analysis and control. On this line of thought, this article aims to answer the following question: Can a transformation of the generalized coordinates under which the actuators directly perform work on a subset of the configuration variables be found? We not only show that the...

journal article 2024

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Physics-Informed Neural Networks to Model and Control Robots: A Theoretical and Experimental Investigation

Liu, J. (author), Borja, Pablo (author), Della Santina, C. (author)

This work concerns the application of physics-informed neural networks to the modeling and control of complex robotic systems. Achieving this goal requires extending physics-informed neural networks to handle nonconservative effects. These learned models are proposed to combine with model-based controllers originally developed with first...

journal article 2024

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Model and Control of R-Soft Inverted Pendulum

Caradonna, Daniele (author), Pierallini, M. (author), Della Santina, C. (author), Angelini, Franco (author), Bicchi, Antonio (author)

Soft robots enable safe and robust operations in unstructured environments. However, the nonlinearities of their continuum structure complicate the accomplishment of classic robotic tasks, such as pick and place. In this work, we propose the R-Soft Inverted Pendulum, a Soft Inverted Pendulum (SIP) actuated only by a revolute joint at the base...

journal article 2024

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Model-Based Control for Soft Robots With System Uncertainties and Input Saturation

Shao, X. (author), Pustina, P. (author), Stölzle, Maximilian (author), Sun, Guanghui (author), De Luca, Alessandro (author), Wu, Ligang (author), Della Santina, C. (author)

Model-based strategies are a promising solution to the grand challenge of equipping continuum soft robots with motor intelligence. However, finite-dimensional models of these systems are inherently inaccurate, thus posing pressing robustness concerns. Moreover, the actuation space of soft robots is usually limited. This article aims at solving...

journal article 2024

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P-satI-D Shape Regulation of Soft Robots

Pustina, P. (author), Borja, Pablo (author), Della Santina, C. (author), De Luca, Alessandro (author)

Soft robots are intrinsically underactuated mechanical systems that operate under uncertainties and disturbances. In these conditions, this letter proposes two versions of PID-like control laws with a saturated integral action for the particularly challenging shape regulation task. The closed-loop system is asymptotically stabilized and...

journal article 2023

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Does enforcing glenohumeral joint stability matter?: A new rapid muscle redundancy solver highlights the importance of non-superficial shoulder muscles

Belli, I. (author), Joshi, S.D. (author), Prendergast, J.M. (author), Beck, I.L.Y. (author), Della Santina, C. (author), Peternel, L. (author), Seth, A. (author)

The complexity of the human shoulder girdle enables the large mobility of the upper extremity, but also introduces instability of the glenohumeral (GH) joint. Shoulder movements are generated by coordinating large superficial and deeper stabilizing muscles spanning numerous degrees-of-freedom. How shoulder muscles are coordinated to stabilize...

journal article 2023

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Embodying Quasi-Passive Modal Trotting and Pronking in a Sagittal Elastic Quadruped

Calzolari, Davide (author), Della Santina, C. (author), Giordano, Alessandro M. (author), Schmidt, Annika (author), Albu-Schaffer, Alin (author)

Animals rely on the elasticity of their tendons and muscles to execute robust and efficient locomotion patterns for a vast and continuous range of velocities. Replicating such capabilities in artificial systems is a long-lasting challenge in robotics. By taking advantage of a pitch dynamics decoupling spring potential, this work aims to...

journal article 2023

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On the stability of the soft pendulum with affine curvature: open-loop, collocated closed-loop, and switching control

Trumic, Maja (author), Della Santina, C. (author), Jovanovic, Kosta (author), Fagiolini, Adriano (author)

This letter investigates the stability properties of the soft inverted pendulum with affine curvature - a template model for nonlinear control of underactuated soft robots. We look at how changes in physical parameters affect stability and equilibrium. We give conditions under which zero dynamics corresponding to a collocated choice of the...

journal article 2023

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How can LLMs transform the robotic design process?

Stella, F. (author), Della Santina, C. (author), Hughes, Josie (author)

We show that large language models (LLMs), such as ChatGPT, can guide the robot design process, on both the conceptual and technical level, and we propose new human–AI co-design strategies and their societal implications.

journal article 2023

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Robotic Monitoring of Habitats: the Natural Intelligence Approach

Angelini, Franco (author), Angelini, Pierangela (author), Angiolini, Claudia (author), Bagella, Simonetta (author), Caccianiga, Marco (author), Della Santina, C. (author), Gigante, Daniela (author), Hutter, Marco (author), Nanayakkara, Thrishantha (author)

In this paper, we first discuss the challenges related to habitat monitoring and review possible robotic solutions. Then, we propose a framework to perform terrestrial habitat monitoring exploiting the mobility of legged robotic systems. The idea is to provide the robot with the Natural Intelligence introduced as the combination of the...

journal article 2023

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Model-Based Control of Soft Robots: A Survey of the State of the Art and Open Challenges

Della Santina, C. (author), Duriez, Christian (author), Rus, Daniela (author)

From a functional standpoint, classic robots are not at all similar to biological systems. If compared with rigid robots, animals' bodies look overly redundant, imprecise, and weak. Nevertheless, animals can still perform a vast range of activities with unmatched effectiveness. Many studies in biomechanics have pointed to the elastic and...

journal article 2023

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A Provably Stable Iterative Learning Controller for Continuum Soft Robots

Pierallini, M. (author), Stella, F. (author), Angelini, Franco (author), Deutschmann, Bastian (author), Hughes, Josie (author), Bicchi, Antonio (author), Garabini, Manolo (author), Della Santina, C. (author)

Fully exploiting soft robots' capabilities requires devising strategies that can accurately control their movements with the limited amount of control sources available. This task is challenging for reasons including the hard-to-model dynamics, the system's underactuation, and the need of using a prominent feedforward control action to...

journal article 2023

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Forecasting infections with spatio-temporal graph neural networks: a case study of the Dutch SARS-CoV-2 spread

Croft, V.M. (author), van Iersel, Senna C. J. L. (author), Della Santina, C. (author)

The spread of an epidemic over a population is influenced by a multitude of factors having both spatial and temporal nature, which are hard to completely capture using first principle methods. This paper concerns regional forecasting of SARS-Cov-2 infections 1 week ahead using machine learning. We especially focus on the Dutch case study for...

journal article 2023

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Robust Jumping with an Articulated Soft Quadruped via Trajectory Optimization and Iterative Learning

Ding, J. (author), Sels, Mees A.van Loben (author), Angelini, Franco (author), Kober, J. (author), Della Santina, C. (author)

Quadrupeds deployed in real-world scenarios need to be robust to unmodelled dynamic effects. In this work, we aim to increase the robustness of quadrupedal periodic forward jumping (i.e., pronking) by unifying cutting-edge model-based trajectory optimization and iterative learning control. Using a reduced-order soft anchor model, the...

journal article 2023

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Experimental Closed-Loop Excitation of Nonlinear Normal Modes on an Elastic Industrial Robot

Bjelonic, Filip (author), Sachtler, Arne (author), Albu-Schaffer, Alin (author), Della Santina, C. (author)

Adding elastic elements to the mechanical structure should enable robots to perform efficient oscillatory tasks. Still, even characterizing natural oscillations in nonlinear systems is a challenge in itself, which nonlinear modal theory promises to solve. Therein eigenmanifolds generalize eigenspaces to mechanical systems with non-Euclidean...

journal article 2022

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On the Role of Coupled Damping and Gyroscopic Forces in the Stability and Performance of Mechanical Systems

Borja Rosales, L.P. (author), Della Santina, C. (author), Dabiri, A. (author)

Damping injection is a well-studied tool in nonlinear control theory to stabilize and shape the transient of mechanical systems. Interestingly, the injection of coupled damping yielding gyroscopic forces has received far less attention. This letter aims to fill this gap for gyroscopic forces that couple actuated and unactuated coordinates. First...

journal article 2022

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Controlling Maneuverability of a Bio-Inspired Swimming Robot Through Morphological Transformation: Morphology Driven Control of a Swimming Robot

Junge, Kai (author), Obayashi, Nana (author), Stella, F. (author), Della Santina, C. (author), Hughes, Josie (author)

Biology provides many examples of how body adaption can be used to achieve a change in functionality. The feather star, an underwater crinoid that uses feather arms to locomote and feed, is one such system; it releases its arms to distract prey and vary its maneuverability to help escape predators. Using this crinoid as inspiration, we develop a...

journal article 2022

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Learning 3D Shape Proprioception for Continuum Soft Robots with Multiple Magnetic Sensors

Baaij, T.A. (author), Klein Holkenborg, Marn (author), Stölzle, Maximilian (author), van der Tuin, Daan (author), Naaktgeboren, Jonatan (author), Babuska, R. (author), Della Santina, C. (author)

Sensing the shape of continuum soft robots without obstructing their movements and modifying their natural softness requires innovative solutions. This letter proposes to use magnetic sensors fully integrated into the robot to achieve proprioception. Magnetic sensors are compact, sensitive, and easy to integrate into a soft robot. We also...

journal article 2022