Comments on "Structure design of two types of sliding-mode controllers for a class of under-actuated mechanical systems"

TL;DR

This paper critically examines two sliding-mode controllers for under-actuated mechanical systems, demonstrating through counterexamples and simulations that they fail to achieve stabilization, thus questioning their effectiveness.

Contribution

It provides a critical analysis showing the limitations of existing sliding-mode controllers for certain under-actuated systems, highlighting the need for improved control strategies.

Findings

The controllers fail to stabilize the systems in counterexamples.

Simulation results confirm the controllers' inadequacy.

Theoretical analysis explains the failure modes.

Abstract

In this note, it is shown by counterexamples, theoretical analysis and simulation tests that the two types of sliding-mode controllers presented in the paper [1] fail to solve the stabilization problem of a class of under-actuated mechanical systems.