The control of articulated soft robots, i.e. robots with flexible joints and rigid links, presents a challenge due to their in- trinsic elastic elements and nonlinear force-deflection dependency. This letter first proposes a discrete-time delayed unknown input- state observer based on a nominal robot model that reconstructs the total torque disturbance vector, resulting from the imperfect knowledge of the elastic torque characteristic, external torques, and other model uncertainties. Then, it introduces a robust controller, that actively compensates for the estimated uncertainty and allows bounded stability for the tracking of independent link position and joint stiffness reference signals. The convergence of the disturbance estimator and the overall system’s stability in closed loop is proven analytically, while the effectiveness of the proposed control design is first evaluated in simulations with respect to large uncertainty conditions, and then demonstrated through experiments on a real multi-degree-of-freedom articulated soft robot.

Pedone S., Trumic M., Jovanovic K., & Fagiolini A. (2022). Robust and Decoupled Position and Stiffness Control for Electrically-Driven Articulated Soft Robots. IEEE ROBOTICS AND AUTOMATION LETTERS, 7(4), 9059-9066 [10.1109/LRA.2022.3188903].

Robust and Decoupled Position and Stiffness Control for Electrically-Driven Articulated Soft Robots

Pedone S.;Trumic M.;Fagiolini A.
2022

Abstract

The control of articulated soft robots, i.e. robots with flexible joints and rigid links, presents a challenge due to their in- trinsic elastic elements and nonlinear force-deflection dependency. This letter first proposes a discrete-time delayed unknown input- state observer based on a nominal robot model that reconstructs the total torque disturbance vector, resulting from the imperfect knowledge of the elastic torque characteristic, external torques, and other model uncertainties. Then, it introduces a robust controller, that actively compensates for the estimated uncertainty and allows bounded stability for the tracking of independent link position and joint stiffness reference signals. The convergence of the disturbance estimator and the overall system’s stability in closed loop is proven analytically, while the effectiveness of the proposed control design is first evaluated in simulations with respect to large uncertainty conditions, and then demonstrated through experiments on a real multi-degree-of-freedom articulated soft robot.
Settore ING-INF/04 - Automatica
Pedone S., Trumic M., Jovanovic K., & Fagiolini A. (2022). Robust and Decoupled Position and Stiffness Control for Electrically-Driven Articulated Soft Robots. IEEE ROBOTICS AND AUTOMATION LETTERS, 7(4), 9059-9066 [10.1109/LRA.2022.3188903].
File in questo prodotto:
File Dimensione Formato  
C06_RAL22_Robust_Control_of_ASR.pdf

non disponibili

Tipologia: Versione Editoriale
Dimensione 1.73 MB
Formato Adobe PDF
1.73 MB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/10447/566205
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 0
  • ???jsp.display-item.citation.isi??? ND
social impact