Comments on ‘Differentiator application in altitude control for an indoor blimp robot’

Contributions to numerical differentiation using orthogonal polynomials and its application to fault detection and parameter identification

“…Ensuite, 1. INTRODUCTION (1971); Hanke and Scherzer (2001); Kantz and Schreiber (2004)) to a variety of problems in engineering (see, e.g., Diop, Grizzle, Moraal, and Stefanopoulou (1994); Levant (2003); Mboup, Join, and Fliess (2007); Mboup et al (2020); Reger, Sira-Ramírez, and Fliess (2005); Wang, Zheng, Efimov, and Perruquetti (2018)). Estimating derivatives is, however, a challenging and ill-posed problem in the sense that a small error in the measured signal can yield notable errors in the approximated derivatives.…”

An Experimental Investigation of Discretized Homogeneous Differentiators: Pneumatic Actuator Case

“…Some classes of differentiators, including homogeneous, high order sliding mode, high-gain and ALIEN differentiators (e.g. [2], [3]) are discussed and compared in [4], [5] in the framework of indoor small blimp robot's altitude control, but without taking into account the influence of the sampling period. In the last decade, Acary & Brogliato [6] introduced the implicit discretization, whose purpose is to replace the sign function by an implicit projector.…”