Taylor‐based adaptive sliding mode control method for robot manipulators

• Published in: IET control theory & applications Vol. 17; no. 9; pp. 1105 - 1115
• Main Authors: Fateh, Alireza, Momeni, Hamidreza, Masouleh, Mehdi Tale
• Format: Journal Article
• Language: English
• Published: Stevenage John Wiley & Sons, Inc 01.06.2023; Wiley
• Subjects: Adaptive control; adaptive estimation; Approximation; Attenuation; Boundary layers; chattering attenuation; Control methods; Design; Invariants; Manipulators; Methods; Robot arms; Robot control; Robots; Robust control; Sliding mode control; Taylor series; Uncertainty; Upper bounds
• ISSN: 1751-8644; 1751-8652
• DOI: 10.1049/cth2.12438

This paper develops a novel Taylor‐based adaptive sliding mode control method (ASMC) for robot manipulators. In the first new scheme, sliding mode control (SMC) is effectively enhanced using the Taylor expansion for achieving a less conservative sign‐function gain that enables chattering attenuation. After that, a new Taylor‐based adaptive SMC scheme is proposed without prior knowledge of the upper bound of uncertainty and the Taylor expansion coefficients. Then, a new Taylor‐based boundary layer ASMC scheme is proposed for chattering attenuation. As a fact, no chattering is expected to be observed as long as the sliding surface remains an invariant set. However, the sliding surface will not be an invariant set unless the sign‐function is precisely determined on the sliding surface. It is verified that the sign‐function cannot be precisely determined on the sliding surface due to the presence of uncertainty, hence, the chattering phenomenon. In the new Taylor‐based boundary layer ASMC scheme, the conventional ASMC is modified by removing the sign‐function in the vicinity of the sliding surface and using the Taylor expansion to estimate and compensate for the uncertainty. Compared to a time‐delay ASMC applied to a robot manipulator, the Taylor‐based ASMC scheme exhibits a less conservative sign‐function gain resulting in chattering attenuation. A novel Taylor‐based adaptive sliding mode control (ASMC) method for robot manipulators is presented. The ASMC is effectively enhanced using the Taylor expansion for achieving a less conservative sliding gain that enables chattering attenuation.