Control of a two-DOF parallel robot with unknown parameters using a novel robust adaptive approach

Saeed Ansari Rad; Mehran Ghafarian Tamizi; Amin Mirfakhar; Mehdi Tale Masouleh; Ahmad Kalhor

doi:10.1016/j.isatra.2021.02.001

Control of a two-DOF parallel robot with unknown parameters using a novel robust adaptive approach

ISA Trans. 2021 Nov:117:70-84. doi: 10.1016/j.isatra.2021.02.001. Epub 2021 Feb 22.

Authors

Saeed Ansari Rad¹, Mehran Ghafarian Tamizi², Amin Mirfakhar³, Mehdi Tale Masouleh⁴, Ahmad Kalhor⁵

Affiliations

¹ Human and Robotic Interaction Laboratory, School of Electrical and Computer Engineering, University of Tehran, Tehran, Iran. Electronic address: Saeedansari71@ut.ac.ir.
² Human and Robotic Interaction Laboratory, School of Electrical and Computer Engineering, University of Tehran, Tehran, Iran. Electronic address: mehran.ghafarian@ut.ac.ir.
³ University of Science and Technology, Tehran, Iran. Electronic address: mirfakhar_amin@mecheng.iust.ac.ir.
⁴ Human and Robotic Interaction Laboratory, School of Electrical and Computer Engineering, University of Tehran, Tehran, Iran. Electronic address: m.t.masouleh@ut.ac.ir.
⁵ Human and Robotic Interaction Laboratory, School of Electrical and Computer Engineering, University of Tehran, Tehran, Iran. Electronic address: akalhor@ut.ac.ir.

PMID: 33653512
DOI: 10.1016/j.isatra.2021.02.001

Abstract

Model-based methods lose their performance in confronting with model uncertainties and disturbances. Accordingly, some degrees of adaptation to the involved conditions are required. In this paper, a novel robust adaptive scheme is proposed which guarantees the simultaneous identification and control of a system in the presence of external disturbances. Thereafter, the suggested algorithm is implemented on a 2-DOf spherical parallel robot as a stabilizer device. By identifying unknown parameters of Jacobian matrix, the relative identification error is obtained as 0.0207. Applying external excitations to the base, the ratio of end-effector to base orientation is acquired as 0.091, demonstrating proper stabilization in comparison with other two well-known methods. The proposed structure also reveals a reliable performance in tracking desired paths for the end-effector Euler angles.

Keywords: 2-DOF spherical parallel robot; Exponentially decay algorithm; Jacobian matrix; Robust adaptive control; Simultaneous identification and control.