| 1. |
- Bhadani, Kanishk, 1991, et al.
(author)
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Applied Calibration and Validation Method of Dynamic Process Simulation for Crushing Plants
- 2021
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In: Minerals. - : MDPI AG. - 2075-163X. ; 11:9
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Journal article (peer-reviewed)abstract
- There is a need within the production industry for digitalization and the development of meaningful functionality for production operation. One such industry is aggregate production, characterized by continuous production operation, where the digital transformation can bring operational adaptability to customer demand. Dynamic process simulations have the ability to capture the change in production performance of aggregate production over time. However, there is a need to develop cost-efficient methodologies to integrate calibrations and validation of models. This paper presents a method of integrating an experimental and data-driven approach for calibration and validation for crushing plant equipment and a process model. The method uses an error minimization optimization formulation to calibrate the equipment models, followed by the validation of the process model. The paper discusses various details such as experimental calibration procedure, applied error functions, optimization problem formulation, and the future development needed to completely realize the procedure for industrial use. The validated simulation model can be used for performing process planning and process optimization activities for the crushing plant's operation.
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| 2. |
- Gröndahl, Albin, 1994, et al.
(author)
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Impact of Feeding Position on Power Draw and Size Reduction in a Cone Crusher
- 2017
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In: The 15th European Symposium on Comminution and Classification.
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Conference paper (other academic/artistic)abstract
- The power draw of cone crushers, used in comminution and aggregates production, is in most cases monitored with too low sampling rate in comparison to the operating speed. This does not give adequate information on the actual operation mode and performance of the crusher during a full rotation of the eccentric motion of the mantle, leaving variance in the power draw unnoticed. This investigation has utilized a high speed measurement system for power draw on a lab scale cone crusher in order to identify an induced miss alignment in the feed, which is a common operation phenomenon, and the consequences of it. The results show that variations in the feeding alignment can be diagnosed and identified using only power draw measurements and that there are possibilities to use the approach for future control systems to improve fatigue life, operating efficiency, production yield and liberation in comminution processes.
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| 3. |
- Asbjörnsson, Gauti, 1985, et al.
(author)
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A Training Simulator for Crushing Plant Operators
- 2012
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In: XXVI International Mineral Processing Congress (IMPC 2012: Innovative Processing for Sustainable Growth; New Delhi; India; 24 September 2012 through 28 September 2012). - 9788190171434 ; , s. 2164-2171
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Conference paper (peer-reviewed)abstract
- Crushing plants are widely used around the world as a pre-processing step in the mineral and mining industries and as standalone processing plants in the aggregates industry. Despite automation and different advanced model predictive control a lot of the process is still managed by operators. The operators affect a lot of the performance. The numbers of the improvement they can achieve are at least as big as the advanced control algorithms’, today. Therefore it is also important to train the operators so they know how to behave in different situations. Models for crushers and other production units have been developed during the years and the latest add is the different units’ dynamic behavior being brought in, which gives the crushing plants dynamic time dependant performance. This can be used as a simulator for operators training. By connecting a Human Machine Interface (HMI) to a dynamic simulator with the models incorporated, a training environment for operators can be achieved. In this paper a dynamic crushing plant simulator implemented in MATLAB/SIMULINK has been connected to an HMI via a PLC. The HMI is placed in a control room at the university and complemented with monitors showing sequences from the process connected to the simulations, thus creating a realistic control room for training. In the created training environment the operators can be trained under realistic conditions. Simple training scenarios and how they could be simulated are discussed. Apart from the increased level of knowledge and experience among the operators, the time is an important factor. While a real crushing plant is still being built, the operators to be can already be trained, saving a lot of the commissioning time.
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| 4. |
- Asbjörnsson, Gauti, 1985, et al.
(author)
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An On-line Training Simulator Built on Dynamic Simulations of Crushing Plants
- 2013
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In: IFAC Proceedings Volumes (IFAC-PapersOnline). - 2405-8963. - 9783902823427 ; 15:1, s. 218-223
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Conference paper (peer-reviewed)abstract
- Crushing plants are widely used around the world as a pre-processing step in the mineral and mining industries or as standalone processing plants for final products in the aggregates industry. Despite automation and different types of advanced model predictive control, many the processes are still managed by operators. The skill of the operators influences the process performance and thus production yield. Therefore, it is important to train the operators so they know how to behave in different situations and to make them able to operate the process in the best possible way. Different types of models for crushers and other production units have been developed during the years and the latest improvement is the addition of dynamic behavior which gives the crushing plants a time dependent behavior and performance. This can be used as a simulator for operators training. By connecting an Internet based Human Machine Interface (WebHMI) to a dynamic simulator with the models incorporated, an on-line training environment for operators can be achieved. In this paper, a dynamic crushing plant simulator implemented in MATLAB/SIMULINK has been connected to a WebHMI. The WebHMI is accessible via the Internet, thus creating a realistic control room for operators’ training. In the created training environment, the operators can be trained under realistic conditions. Simple training scenarios and how they could be simulated are discussed. Apart from the increased level of knowledge and experience among the operators, the time aspect is an important factor. While a real crushing plant is still being built, the operators to be can already be trained, saving a lot of the commissioning and ramp up time.
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| 5. |
- Asbjörnsson, Gauti, 1985, et al.
(author)
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Application of Design of Experiments (DoE) in Evaluating Crusher Circuit Performance
- 2023
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Conference paper (other academic/artistic)abstract
- The configuration and the interaction between the crushers and screens enable aggregate producers to produce products that are in accordance with the applicable product certification. However, the performance of the system is seldom optimized for the given conditions and market demand. This paper aims to describe the experimental work and the results of quantifying the crusher and screen performance by applying design of experiments in a full-scale tertiary crushing process of an aggregate production plant with both standard belt-cut sampling as well with continuous processes monitoring. The research output is able to demonstrate that there exists an interaction effect between the crusher closed side setting and eccentric speed that previously has not been identified with traditional methods. The quantification of interaction between crusher and screen individual performance to the process performance have been demonstrated with both belt-cut samples and continuous process monitoring.
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| 6. |
- Asbjörnsson, Gauti, 1985, et al.
(author)
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Application of the Hilbert Transform for Diagnostic and Control in Crushing
- 2020
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In: Minerals Engineering. - : Elsevier BV. - 0892-6875. ; 147
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Journal article (peer-reviewed)abstract
- The performance of a crusher is an essential element in achieving efficient production of aggregates or metals. The process performance depends on the design and configuration of each process equipment, the configuration of the plant, the design of the control and physical properties of the incoming feed. Crushers, however, do not operate in an ideal condition, and as a result, the crusher’ structure, electrical drive and hydraulic system will experience an uneven load during operation. This paper aims to adapt a Hilbert transform to characterise the pressure variations in actual crushers during operation and to set up potential strategies for quantifying the variation. Two applications are also proposed for how this could be used in operation to compensate for the disturbances from unwanted loading conditions that affect the crusher performance.
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| 7. |
- Asbjörnsson, Gauti, 1985, et al.
(author)
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Comminution process modelling from a sustainability perspective
- 2018
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In: 11th International Comminution Symposium (Comminution '18). - 9781510883789
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Conference paper (peer-reviewed)abstract
- Mining is one of the largest industries in the world and contributes largely to the environmental emissions as well as gross domestic product growth for many countries. The demand for sustainability in the industry is continuously increasing with efforts such life cycle assessment, circular economy and even fairtrade to improve the entire supply chain from different perspectives. The process of comminution is subjected to different conditions and will influence the performance of the process and utilization of resources. In this paper the aim is to simulate comminution circuit from an operational perspective with dynamic simulations to evaluate process performance and environmental impacts and to compare it to a cradle-to-gate process. By integrating the environmental impacts into the dynamic process simulations, a higher simulation fidelity can be achieved to provide an extended operational and environmental perspective to the process assessment.
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| 8. |
- Asbjörnsson, Gauti, 1985, et al.
(author)
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Continuous Assignment Development on Topology Optimization in Engineering Design
- 2022
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Conference paper (other academic/artistic)abstract
- An engineering course assignment needs to be designed as a stimulating and challenging task for actively engaging students. It is typically required to be solved in an iterative approach using lectures, reading materials, software tools and supervision sessions. Assignments allow for a practical application of a theory to enhance the students’ understanding of the topic with active learning activities to gain continuous engagement in the course. In the Engineering Design and Optimization course at the Chalmers University of Technology, there is a good balance of theoretical lectures and practical aspects in the assignments. One of these assignments is called the cantilever beam challenge. The students are given an iterative task of designing a cantilever beam based on their previous engineering know-how in the first iteration and applying Topology Optimization on a defined design space to minimise compliance and mass in the second set of iterations. This paper aims to examine the students’ performance, from the start of the course, concerning the development that has happened regarding the different software solutions and different additive manufacturing techniques, and to provide the students’ opinions on the assignment. Each year, this particular assignment ranks high in the course evaluation due to its framework, competitiveness and instant feedback on the proposed design solutions with computer analysis and physical experiments with 3D printed models. However, the interesting questions are whether more advanced tools and algorithms support students learning and whether the beams’ performance improves.
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| 9. |
- Asbjörnsson, Gauti, 1985
(author)
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Crushing Plant Dynamics
- 2015
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Doctoral thesis (other academic/artistic)abstract
- The performance of a crushing plant is an essential element in achieving efficient production of aggregates or metals. A crushing plant´s operating performance depends on the design and configuration of each individual process unit, the configuration of the plant, the design of the control system, events occurring in the process and the physical properties of the incoming feed. The production process is a continuous process and as such it is also subjected to variations and changes in performance depending on the condition of the process. Crushing plants however, are traditionally simulated with steady-state simulation models which are not capable of predicting these conditions. A different technique is therefore necessary in order to estimate the actual behaviour of the plant with respect to time.Crushing plants are affected by both gradual and discrete changes in the process over time which alters the performance of the entire system, making it dynamic. A dynamic simulation is defined in this thesis as continuous simulations with sets of differential equations with static equations to reproduce the dynamic performance of a system. In this thesis multiple operational issues have been identified in order to achieve adequate process fidelity for simulation purposes. These operational issues have been addressed by introducing methods and models for representing different dynamic aspects of the process. These include: different types of bins to handle misaligned feeding, segregation and different flow behaviour, the use of system identification to measure actuator response to accurately estimate unit response, wear estimation for crushers, mechanistic models for crushers and screens for more accurate estimation of unit dynamics, segmented conveyors that can estimate material flow for conveyors with variable speed drives, parameter selection for optimum process performance, discrete events that occur within the process and different control strategies to capture the process dynamics.Different applications for dynamic simulation have been explored and demonstrated in this thesis. These include: process evaluation, control development, process optimization, operational planning, maintenance scheduling and operator training. Each of these areas puts different constraints on the modelling of crushing plants and the level of fidelity, which is determined by the purpose of the simulation.In conclusion, dynamic simulation of production processes has the ability to provide the user with in-depth understanding about the simulated process, details that are usually not available with static simulations. Multiple factors can affect the performance of a crushing plant, factors that need to be included in the simulation to be able to estimate the actual plant performance.
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| 10. |
- Asbjörnsson, Gauti, 1985, et al.
(author)
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Development of a cognitive supporting operator training environment
- 2014
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In: 27th International Mineral Processing Congress, IMPC 2014, Santiago, Chile, 20-24 October 2014.
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Conference paper (peer-reviewed)abstract
- In aggregate production and mining the operators are responsible for controlling and monitoring the process to maintain high plant throughput and safe operation. Operators have to make different decisions to control the process due to changed demand on the operation from both management and conditions of the process. The quality of the response and the time it takes for an operator to respond to altered demand relies on what information is available and the experience of the operator.In this work a dynamic simulation platform has been developed to be used for operator training. Models for representing production units and process control for plant simulations have been developed and implemented in MATLAB/SIMULINK to simulate time-dependent plant behavior. Stochastic and scheduled events are included using the discrete events simulation toolbox SimEvents. The human-machine interface was developed using the human-machine interface software ICONICS. The operators’ cognitive process, in interpreting the plants semantic, has been studied by observations and with informal interviews with operators. This was done to get information about the daily operation and the problems that occur in the process. By interacting with operators that experience different physical interactions with the process; more qualitative e-learning software for supporting operator training in a dynamic operator environment could be developed. The quality of the operator training environment was evaluated with a usability study that was performed with operators and others within the production.
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