ETD

Archivio digitale delle tesi discusse presso l'Università di Pisa

Tesi etd-06012021-193558


Tipo di tesi
Tesi di dottorato di ricerca
Autore
MENGACCI, RICCARDO
URN
etd-06012021-193558
Titolo
DESIGN AND METHODS FOR COMPLIANT CONTROL OF ARTICULATED SOFT ROBOTS
Settore scientifico disciplinare
ING-INF/04
Corso di studi
INGEGNERIA DELL'INFORMAZIONE
Relatori
tutor Prof. Bicchi, Antonio
tutor Prof. Garabini, Manolo
tutor Dott. Catalano, Manuel Giuseppe
Parole chiave
  • compliant systems
  • variable stiffness actuators
  • Articulated soft robots
Data inizio appello
08/06/2021
Consultabilità
Non consultabile
Data di rilascio
08/06/2024
Riassunto
Nowadays, we are observing the growth of a new generation of robots, able to
safely collaborate and cohabit with people, interacting with them and with unstructured
environments. These robots are characterized by having lightweight
structures and by presenting a gentle way of interacting with the external world.
To face the challenges posed by the human/environment-robot interaction, novel
control methods and robotic structure designs have been presented in the past years.
The key idea was the introduction of force/impedance modulation. From one side,
actively through impedance controllers, adopted e.g., in collaborative robots of modern
industries, and from the other side by inserting passive compliant elements in the
robot’s structure, leading to soft robotics.
Both these two approaches allow us to set the robot to be "soft" or to be "stiff" w.r.t.
the environment. However, a good planning strategy is needed since different tasks may
require different impedance behaviors to be achieved. Besides this, the complexity of
compliant robots, derived mainly by the presence of non-linear elastic mechanisms,
increases the difficulty in modeling the system. This makes the use of classical modelbased
control methods less robust. Moreover, the elastic behavior of the system may be
altered if a high-gain feedback is used to compensate for the lack of a good model, and
the energy stored within the elastic elements, as well as possible interactions with the
environment, may lead to oscillatory behaviors. For these reasons, new control strategies
that account for the presence of the elastic dynamics should also be developed.
Motivated by this, in this thesis, I present advanced control concepts that allow
achieving the desired link trajectory for soft robots, while simultaneously enabling the
impedance selection, thus preserving their elastic behavior. Furthermore, I propose
methods for planning the trajectory and also the impedance behavior needed to achieve
specific task requirements of these robots. Finally, I present a novel design for the
elastic mechanism that allows improving the range of applicability and overcoming the
limitations of the current implementation. These novel approaches are validated, in this
thesis, through numerical simulations and experimental tests on impedance-controlled
robots and robotic platforms with either variable and fixed stiffness actuators.
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