Learning Mechatronics Using Digital Live Labs

Practical skills training in laboratories are important elements and learning outcomes in engineering education, where leaners, through exploration, experimentation and reflection engage in inquiry-based learning that stimulate the acquisition of deep conceptual domain knowledge and inquiry skills. Traditional lab environments are very costly to maintain, partly unsafe and often require proximity of instructors and/or students that is in conflict with the Covid-19-driven need for physical/social distancing. In this paper, we describe and evaluate a course in logic control that used online labs both in pure online and in hybrid format. Students reported very high satisfaction with all three formats and achieved similar learning performances. However, qualitative analyses indicate that student learning is deeper and more authentic in the on-campus and hybrid formats compared to the pure online format. Teacher reflections show an overall positive impression of online labs. In conclusion, we recommend the hybrid format as it combines the benefits of online and physical labs, i.e., the flexibility of online laboratory work and realism of hands-on physical laboratory work

Learning Mechatronics Using Digital Live Labs

Practical skills training in laboratories are important elements and learning outcomes in engineering education, where leaners, through exploration, experimentation and reflection engage in inquiry-based learning that stimulate the acquisition of deep conceptual domain knowledge and inquiry skills. Traditional lab environments are very costly to maintain, partly unsafe and often require proximity of instructors and/or students that is in conflict with the Covid-19-driven need for physical/social distancing. In this paper, we describe and evaluate a course in logic control that used online labs both in pure online and in hybrid format. Students reported very high satisfaction with all three formats and achieved similar learning performances. However, qualitative analyses indicate that student learning is deeper and more authentic in the on-campus and hybrid formats compared to the pure online format. Teacher reflections show an overall positive impression of online labs. In conclusion, we recommend the hybrid format as it combines the benefits of online and physical labs, i.e., the flexibility of online laboratory work and realism of hands-on physical laboratory work

Model Reduction for Control of Stirred Tank Reactor Processes

Models of chemical processes have a tendency of being far too complex for controller design. In many cases these models are also too complex for simulation together with other sub-systems, due to long simulation times and numerical problems. Therefore, simplistic models are often used for controller design and simulation with a weak justification of the simplifying assumptions.In this thesis, a systematic method for development and evaluation of simplified models used in closed loop is presented. The method is applied to continuously operated tank reactor systems with a temperature dependent first order, A -> B, exothermic reaction. Both a non-ideally and an ideally stirred tank reactor are described by rigorous models. These detailed models are linearized and used as reference models when the simplified models are investigated. The simplified models are derived by physical approximations applied to the detailed models. Particular focus is on assumptions of constant densities and of constant specific heat capacities as well as on variations in some key parameters.In the evaluation method controllers are developed for the simplified models. The resulting closed loop sensitivity functions are then compared to the sensitivity functions of the original detailed models in closed loop with the same controllers. Measures for these comparisons are suggested and successfully applied on both the non-ideally and on the ideally stirred tank reactor models.A large number of sets of substances have been investigated by means of parameter variations. The evaluation of these sets has resulted in boundaries in the temperature dependent functions for the specific heat capacities and the densities. Within the boundaries the approximation of interest will not particularly affect the behaviour of the closed loop system.A control strategy has also been developed for one of the tank reactor models. The control strategy is based on Quantitative Feedback Theory. The control is attractive since it uses only a small number of linear controllers for a large operating range

Model Reduction for Control of Stirred Tank Reactor Processes

Models of chemical processes have a tendency of being far too complex for controller design. In many cases these models are also too complex for simulation together with other sub-systems, due to long simulation times and numerical problems. Therefore, simplistic models are often used for controller design and simulation with a weak justification of the simplifying assumptions.In this thesis, a systematic method for development and evaluation of simplified models used in closed loop is presented. The method is applied to continuously operated tank reactor systems with a temperature dependent first order, A -> B, exothermic reaction. Both a non-ideally and an ideally stirred tank reactor are described by rigorous models. These detailed models are linearized and used as reference models when the simplified models are investigated. The simplified models are derived by physical approximations applied to the detailed models. Particular focus is on assumptions of constant densities and of constant specific heat capacities as well as on variations in some key parameters.In the evaluation method controllers are developed for the simplified models. The resulting closed loop sensitivity functions are then compared to the sensitivity functions of the original detailed models in closed loop with the same controllers. Measures for these comparisons are suggested and successfully applied on both the non-ideally and on the ideally stirred tank reactor models.A large number of sets of substances have been investigated by means of parameter variations. The evaluation of these sets has resulted in boundaries in the temperature dependent functions for the specific heat capacities and the densities. Within the boundaries the approximation of interest will not particularly affect the behaviour of the closed loop system.A control strategy has also been developed for one of the tank reactor models. The control strategy is based on Quantitative Feedback Theory. The control is attractive since it uses only a small number of linear controllers for a large operating range

Dare to Teach Sustainability

The future role of engineers is facing a shift in focus, from finding technical solutions to sustainable technical solutions. This shift will require engineers to have a different approach to sustainability and technical development. Introducing the Sustainable Development Goals can be considered in conformity with the more traditional methods of engineering where the goals can be seen as a specification where technology can contribute. This change is not only a challenge for the students but also for the teachers. For many teachers, sustainable development was not a part of their education and is not within their area of expertise. Therefore, many teachers feel uncomfortable about teaching sustainable development och struggle with how to incorporate it into their everyday teaching. Other teachers are experts in sustainable development but not in the specific discipline (here electrical engineering or mechatronics). The students need to learn how sustainable development is connected to their specific discipline. A method to introducing the sustainable development goals in discipline focused courses is presented, as inspiration for other teachers. The purpose was to create an assignment that all students found to be interesting and still not require the teacher to become an expert. The assignment was integrated in two discipline focused courses in the first and second cycle. The course evaluations showed that the majority of the students stated that the course had improved their understanding of the Sustainable Development Goals and the direct connection to their discipline was appreciated at both levels and made the assignments considered useful

Closed loop model reduction applied to a tank reactor process

The subject of this article is the direct assessment of model simplification from a feedback control perspective. Normally, dynamic systems are simplified dimensionally and structurally from an open loop perspective. In spite of the intentions, the resulting models often tend to be unnecessary complex for controller design and synthesis anyway. Here, a four step method is proposed that incorporates a feedback controller, and makes use of the closed loop sensitivity functions to indicate significant impact on the closed loop behaviour from a performed model simplification. The method is applied to a first order reaction in an ideally stirred tank reactor with a cooling system. For this system a general detailed model is derived. The model includes temperature dependent parameters such as specific heats and densities. This reference model is locally unstable in most operating points, making open loop simplification impractical. The proposed closed loop simplification method makes it possible to evaluate which approximations of the system that can be justified

Closed loop model reduction applied to a tank reactor process

The subject of this article is the direct assessment of model simplification from a feedback control perspective. Normally, dynamic systems are simplified dimensionally and structurally from an open loop perspective. In spite of the intentions, the resulting models often tend to be unnecessary complex for controller design and synthesis anyway. Here, a four step method is proposed that incorporates a feedback controller, and makes use of the closed loop sensitivity functions to indicate significant impact on the closed loop behaviour from a performed model simplification. The method is applied to a first order reaction in an ideally stirred tank reactor with a cooling system. For this system a general detailed model is derived. The model includes temperature dependent parameters such as specific heats and densities. This reference model is locally unstable in most operating points, making open loop simplification impractical. The proposed closed loop simplification method makes it possible to evaluate which approximations of the system that can be justified