| 1. |
- Duarte, Robson A., et al.
(author)
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Calibration and Validation of a Cone Crusher Model with Industrial Data
- 2021
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In: Minerals. - : MDPI. - 2075-163X. ; 11:11
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Journal article (peer-reviewed)abstract
- This paper reports the calibration and validation of a cone crusher model using industrial data. Usually, there are three calibration parameters in the condensed breakage function; by contrast, in this work, every entry of the lower triangular breakage function matrix is considered a calibration parameter. The calibration problem is cast as an optimization problem based on the least squares method. The results show that the calibrated model is able to fit the validation datasets closely, as seen from the low values of the objective function. Another significant advantage of the proposed approach is that the model can be calibrated on data that are usually available from industrial operation; no additional laboratory tests are required. Calibration and validation tests on datasets collected from two different mines show that the calibrated model is a strong candidate for use in various dynamic simulation applications, such as control system design, equipment sizing, operator training, and optimization of crushing circuits.
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| 2. |
- de Souza, Leonardo C. O., et al.
(author)
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Performance Analysis of a Silo-SlideGate-Feeder System to Regulate the Ore Flow by DEM Simulation
- 2022
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In: Journal of Control, Automation and Electrical Systems. - : Springer. - 2195-3880 .- 2195-3899. ; 33:4, s. 1310-1318
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Journal article (peer-reviewed)abstract
- Severe variability of fresh feed ore flowrate in a crushing circuit may cause some operational damages. Related issues include conveyor belt and sieves overload, interlocked crushers, early equipment wear, and silos overflow. Usually, the speed of feeders is used to control the ore output from silos; however, it is ineffective in regulating the height of material carried by the feeder. The introduction of a slide gate in the primary silo of the crushing circuit is an alternative to increase the degree of freedom for controlling the fresh ore flowrate. This paper presents a numerical simulation using a discrete element method (DEM) applied in a silo-gate-feeder system. The simulated model is based on parameters from a Vale’s iron ore beneficiation plant located in Serra Leste Mine, city of Curionópolis, Brazil. The simulation was carried out using the software Siemens Star CCM+ ®. Three scenarios were evaluated, such as changes in the slide gate aperture. The results show that regulating the feeder speed simultaneously with the gate aperture provides a novel control strategy to reduce variability in fresh ore flowrate. The best simulation result reduced in about 11% the variability flowrate compared with the case with no slide gate.
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| 3. |
- Euzébio, Thiago A. M., et al.
(author)
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Decentralized PID controller tuning based on nonlinear optimization to minimize the disturbance effects in coupled loops
- 2021
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In: IEEE Access. - : IEEE. - 2169-3536. ; 9, s. 156857-156867
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Journal article (peer-reviewed)abstract
- Decentralized proportional-integral-derivative (PID) control systems are widely used for multiple-input multiple-output (MIMO) control problems. However, decentralized controllers cannot suppress the plant interactions in multivariable systems, which are addressed in the controller tuning phase. In this paper, a decentralized PID tuning method is proposed in order to minimize the undesirable effects of the coupling between the inputs and outputs of the closed-loop system. For this purpose, the PID parameter tuning method solves a nonlinear optimization problem. This optimization problem is formulated with the criteria of the performance, robustness and multivariable stability of the closed-loop system. A single design parameter is required to specify the trade-off between performance and robustness. Simulation studies are conducted to demonstrate the effectiveness of the proposed method. The performance is compared to that of alternative tuning techniques from the literature. Results show that the proposed approach is a feasible candidate for industrial application, as it is simple to implement and capable of addressing robustness and stability concerns of plant operators.
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| 4. |
- Yamashita, Andre S., et al.
(author)
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A review of modeling and control strategies for cone crushers in the mineral processing and quarrying industries
- 2021
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In: Minerals Engineering. - : Elsevier. - 0892-6875 .- 1872-9444. ; 170
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Research review (peer-reviewed)abstract
- Run-of-mine ore is usually too large to be useful for construction or metallurgy. Large particles must be reduced to specific sizes to either comply with aggregate sizing regulations, or facilitate mineral liberation; therefore, in the aggregates and mineral processing industries, run-of-mine ore is broken in crushing circuits by cone crushers. Here, we review the cone crusher literature, focusing on the modeling and control of crushing circuits. A total of 61 works published in the primary literature, ranging from 1972 to 2020, are classified and discussed with respect to the model formulation—i.e., population balance models, empirical models, or data-driven models—and control strategy—i.e., proportional-integral-derivative, model predictive control, expert system, or model-free control. The data are summarized in a table that makes locating a particular formulation or strategy quick and easy. The discussion of the current state of the art of crushing circuit modeling and control technologies consolidates the results available in the literature, as well as the challenges that we must overcome to increase crushing performance through control and optimization. The discussion of future trends brings attention to the discrete element method, model based control, plant-wide and mine-to-mill optimization, and machine learning applications for data acquisition and process optimization.
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| 5. |
- Yamashita, Andre S., et al.
(author)
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Multiobjective tuning technique for MPC in grinding circuits
- 2023
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In: IEEE Access. - : Institute of Electrical and Electronics Engineers (IEEE). - 2169-3536. ; 11, s. 43041-43054
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Journal article (peer-reviewed)abstract
- We investigate the control challenges in grinding circuits—slow dynamics, long dead times, variable coupling— and the controller tuning challenge, that is, the difficulty in translating operating goals into tuning goals and closed-loop performance. A tuning algorithm for DMC (dynamic matrix control), suitable for the mineral processing industry, is proposed. The tuning problem is posed as a multiobjective optimization problem, in which the tuning goals are directly related to the desired closed-loop performance of process variables. The problem is solved using a compromise optimization, which minimizes the Euclidian distance between a feasible solution and the Utopia solution. Three case studies are presented, which validate the tuning algorithm for DMC in linear and non-linear grinding circuit models. The closed-loop performance obtained with the proposed tuning algorithm is compared to the one obtained through a benchmark tuning technique from the literature. The proposed tuning method has the following features: i) it shapes the closed-loop response according to the goal definitions for linear systems; ii) it requires tailored initial guesses and search spaces to converge to a stabilizing solution in non-linear applications; and iii) it allows the user to specify the desired closed-loop performance behavior in the tuning procedure, allowing the implementation of an adequate controller for each situation.
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