Two-Stage Shape Memory Alloy Identification Based on the Hammerstein–Wiener Model

Copaci, Dorin; Moreno, Lourdes; Blanco, María Dolores Valdueza

doi:10.3389/frobt.2019.00083

Cited by 11 publications

(6 citation statements)

References 25 publications

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“…Without the output nonlinearity, the model simplifies to a Hammerstein model, while a linear dynamic system followed by a nonlinear static function is a Wiener model. Hammerstein, Wiener, and HW models have been widely used due to their relative simplicity and capability to describe many nonlinear dynamic systems [20,[24][25][26]. The HW model proposed here is written as follows:…”

Section: Hammerstein-wiener Nonlinear Modelmentioning

confidence: 99%

Hammerstein–Wiener Model Identification for Oil-in-Water Separation Dynamics in a De-Oiling Hydrocyclone System

Jespersen,

Yang,

Hansen

et al. 2023

Energies

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To reduce the environmental impact of offshore oil and gas, the hydrocarbon discharge regulations tend to become more stringent. One way to reduce the oil discharge is to improve the control systems by introducing new oil-in-water (OiW) sensing technologies and advanced control. De-oiling hydrocyclones are commonly used in offshore facilities for produced water treatment (PWT), but obtaining valid control-oriented models of hydrocyclones has proven challenging. Existing control-oriented models are often based on droplet trajectory analysis. While it has been demonstrated that these models can fit steady-state separation efficiency data, the dynamics of these models have either not been validated experimentally or only describe part of the dynamics. In addition to the inlet OiW concentration, they require the droplet size distribution to be measured, which complicates model validation as well as implementation. This work presents an approach to obtain validated nonlinear models of the discharge concentration, separation efficiency, and discharge rate, which do not require the droplet size distribution to be measured. An exhaustive search approach is used to identify control-oriented polynomial-type Hammerstein–Wiener (HW) models of de-oiling hydrocyclones based on concentration measurements from online OiW monitors. To demonstrate the effectiveness of this modeling approach, a PI controller is designed using the Skogestad internal model control (SIMC) tuning rules to control the discharge OiW concentration directly. The identification experiment emulates an offshore PWT system with installed OiW monitors, which is realistic with the legislative incentive to include online OiW discharge measurements. The proposed approach could enable the application of OiW-based control on existing offshore PWT facilities, resulting in improved de-oiling performance and reduced oil discharge.

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Section: Hammerstein-wiener Nonlinear Modelmentioning

confidence: 99%

Hammerstein–Wiener Model Identification for Oil-in-Water Separation Dynamics in a De-Oiling Hydrocyclone System

Jespersen,

Yang,

Hansen

et al. 2023

Energies

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“…Gain values have been found according to the SMA actuator model, presented in [43], available at Matlab/Simulink ® , and connected with the dynamic model of the neck platform (presented in section IV-A). The dynamic model of the neck platform was modified to receive the tendon displacement as a reference.…”

Section: Bpid Controllermentioning

confidence: 99%

SMA-Driven Soft Robotic Neck: Design, Control and Validation

et al. 2020

Self Cite

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Replicating the behavior and movement of living organisms to develop robots which are better adapted to the human natural environment is a major area of interest today. Soft device development is one of the most promising and innovative technological fields to meet this challenge. However, soft technology lacks of suitable actuators, and therefore, development and integration of soft actuators is a priority. This paper presents the development and control of a soft robotic neck which is actuated by a flexible Shape Memory Alloy (SMA)-based actuator. The proposed neck has two degrees of freedom that allow movements of inclination and orientation, thus approaching the actual movement of the human neck. The platform we have developed may be considered a real soft robotic device since, due to its flexible SMAbased actuator, it has much fewer rigid parts compared to similar platforms. Weight and motion noise have also been considerably reduced due to the lack of gear boxes, housing and bearings, which are commonly used in conventional actuators to reduce velocity and increase torque.

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“…Ag is an important element due to its superior and anti-bacterial material and its stability. Hence, Ag is considered the best element incorporated into Ni-Ti-based alloys to produce Ni-Ti-Ag composite material with higher strength compared with Ni-Ti-based alloys and higher anti-bacterial activity [4][5][6][7][8][9][10][11]. The main manufacturing processes used to produce SMAs are the casting method and powder metallurgy method, followed by heat treatment to minimize the internal stresses and improve the properties of the manufactured SMAs [12].…”

Section: Introductionmentioning

confidence: 99%

Microstructural Analysis and Mechanical Characterization of Shape Memory Alloy Ni-Ti-Ag Synthesized by Casting Route

et al. 2022

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The purpose of the current research is to study the microstructure and mechanical properties of Ni-Ti-Ag shape memory alloys prepared by the casting route. Ag (grain size at 1 mm) was incorporated into Ni-Ti alloys at varying percentages of weight (0, 1.5, 3 and 4.5 wt.% Ag) to produce shape memory alloys using a Vacuum Arc Re-melting (VAR) furnace. Microstructural analysis was defined by FESEM microscopy and XRD examinations, while the transformation temperatures of the Ni-Ti-Ag shape memory alloy were determined by DSC examination. On the other hand, determination of mechanical properties was carried out using micro-hardness and compressive tests. The results of this work show that Ag was dispersed homogeneously into the Ni-Ti alloy. Moreover, two primary phases (austenite phase and martensite phase) emerged with few impurities. The results of the XRD examination show that the number of Ag peaks increased with the increase in weight percentage of Ag. The transformation temperature of the austenitic phase was defined as −1.6 °C by DSC. The mechanical characterizations increased with the increase in weight percentages of Ag (1.5, 3 and 4.5 wt.%), and significantly affected the mechanical properties of the Ni-Ti alloy. An improvement in compressive strength (42.478%) was found for the alloy with 3 wt.% Ag, while the micro-hardness results show a slight decrease in micro-hardness (8.858%) for the alloy with 4.5 wt.% Ag.

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Two-Stage Shape Memory Alloy Identification Based on the Hammerstein–Wiener Model

Cited by 11 publications

References 25 publications

Hammerstein–Wiener Model Identification for Oil-in-Water Separation Dynamics in a De-Oiling Hydrocyclone System

Hammerstein–Wiener Model Identification for Oil-in-Water Separation Dynamics in a De-Oiling Hydrocyclone System

SMA-Driven Soft Robotic Neck: Design, Control and Validation

Microstructural Analysis and Mechanical Characterization of Shape Memory Alloy Ni-Ti-Ag Synthesized by Casting Route

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