Discrete-time differentiators: design and comparative analysis

This work deals with the problem of online differentiation of noisy signals. In this context, several types of differentiators including linear, sliding-mode based, adaptive, Kalman, and ALIEN differentiators are studied through mathematical analysis and numerical experiments. To resolve the drawbacks of the exact differentiators, new implicit and semi-implicit discretization schemes are proposed in this work to suppress the digital chattering caused by the wrong time-discretization of set-valued functions as well as providing some useful properties, e.g., finite-time convergence, invariant sliding-surface, exactness. A complete comparative analysis is presented in the manuscript to investigate the behavior of the discrete-time differentiators in the presence of several types of noises, including white noise, sinusoidal noise, and bell-shaped noise. Many details such as quantization effect and realistic sampling times are taken into account to provide useful information based on practical conditions. Many comments are provided to help the engineers to tune the parameters of the differentiators

Simultaneous fault detection algorithm for grid-connected photovoltaic plants

In this work, the authors present a new algorithm for detecting faults in grid-connected photovoltaic (GCPV) plant. There are few instances of statistical tools being deployed in the analysis of photovoltaic (PV) measured data. The main focus of this study is, therefore, to outline a PV fault detection algorithm that can diagnose faults on the DC side of the examined GCPV system based on the t-test statistical analysis method. For a given set of operational conditions, solar irradiance and module temperature, a number of attributes such as voltage and power ratio of the PV strings are measured using virtual instrumentation (VI) LabVIEW software. The results obtained indicate that the fault detection algorithm can detect accurately different types of faults such as, faulty PV module, faulty PV String, faulty Bypass diode and faulty maximum power point tracking unit. The proposed PV fault detection algorithm has been validated using 1.98 kWp PV plant installed at the University of Huddersfield, UK

Discrete-time differentiators in closed-loop control systems: experiments on electro-pneumatic system and rotary inverted pendulum

This paper is dedicated to the experimental analysis of discrete-time differentiators implemented in closed-loop control systems. To this end, two laboratory setups, namely an electro-pneumatic system and a rotary inverted pendulum have been used to implement 25 different differentiators. Since the selected laboratory setups behave differently in the case of dynamic response and noise characteristics, it is expected that the results remain valid for a wide range of control applications. The validity of several theoretical results, which have been already reported in the literature using mathematical analysis and numerical simulations, has been investigated, and several comments are provided to allow one to select an appropriate differentiation scheme in practical closed-loop control systems

Modeling and control of overhead cranes: a tutorial overview and perspectives

International audienceThis article presents a complete review of the modeling and control schemes for overhead cranes operating in 2D and 3D spaces published to date. The modeling schemes including the pendulum-like models with rigid and flexible links are reviewed and their key characteristics are studied. Subsequently, an overview of the control methods developed for such models is presented. Afterward, a new simulation-oriented model enabling to capture both cables' dynamic and global nonlinearities caused by the pendulation is developed, and different control methods that exist in the literature are evaluated and compared based on this model using numerical experiments. In the end, several research gaps are identified to be considered in future works

Comparison of control methods for 2D industrial cranes

International audienceThis paper aims to review and compare some methods used to control 2D overhead cranes. The properties of the controllers are categorized based on their structure, feedback type (open-loop, collocated, and noncollocated), and their stability (local, global, regulation and tracking). Subsequently, a new model is used to describe the system's behavior more accurately. The model consists of a pendulum with a large number of links attached to a cart, allowing to study global nonlinearities as well as cables' flexibility and vibration, simultaneously. The controllers are then studied by extensive numerical simulations under the regulation and tracking scenarios

Comparison of control methods for 2D industrial cranes

This paper aims to review and compare some methods used to control 2D overhead cranes. The properties of the controllers are categorized based on their structure, feedback type (open-loop, collocated, and noncollocated), and their stability (local, global, regulation and tracking). Subsequently, a new model is used to describe the system's behavior more accurately. The model consists of a pendulum with a large number of links attached to a cart, allowing to study global nonlinearities as well as cables' flexibility and vibration, simultaneously. The controllers are then studied by extensive numerical simulations under the regulation and tracking scenarios

Comparison of control methods for 2D industrial cranes

International audienceThis paper aims to review and compare some methods used to control 2D overhead cranes. The properties of the controllers are categorized based on their structure, feedback type (open-loop, collocated, and noncollocated), and their stability (local, global, regulation and tracking). Subsequently, a new model is used to describe the system's behavior more accurately. The model consists of a pendulum with a large number of links attached to a cart, allowing to study global nonlinearities as well as cables' flexibility and vibration, simultaneously. The controllers are then studied by extensive numerical simulations under the regulation and tracking scenarios