Teaching kinematics and dynamics of multibody mechanical systems using the object oriented language modelica

A new modeling language, called Modelica, for physical modeling is being developed in an international effort. The main objective is to make it easy to exchange models and model libraries for different domains, such as, mechanical, pneumatics, electrical, hydraulics, and others. The design approach builds on non-causal modeling with true ordinary differential and algebraic equations and the use of object-oriented constructs stemming from modern software development, (hierarchy, encapsulation) to facilitate reuse of models and model parts. This paper gives an overview of the use of the object oriented language Modelica with the mechanical Multibody Library to model and simulate three-dimensional mechanical systems

Using advanced simulation techniques to improve industrial controller’s dependability

Modelica Modeling language is powerful and suitable for modeling mechatronic systems, being possible to interact different technological aspects and deal, simultaneously with different technologies (mechanical, electrical, pneumatic, hydraulic,..). In this paper it is discussed, in a case study, the possibility of using this language for modeling an automation system (controller and plant) in closed loop behavior and also in defining some parameters of the automation system in order to optimize some behavior aspects of the system as, for instance, the time cycle of the automation system. Some aspects relied with controllers dependability are also discussed and it is showed how Modelica modeling language can help controllers’ designers improving controllers dependability, when are used Simulation Techniques

Design of a mechatronic system for application of hardware-in-the-loop simulation technique

Classical approaches, using Simulation analysis technique, use a controller model that can – or not – be coupled with a plant model. Usually, the controller and plant models are connected, in a closed-loop behavior, and this kind of Simulation is called Software-in-the-loop Simulation (SIL). However, recently, some directions are being assumed and some recent works deal with Simulation considering the real controller, instead of the controller model, in the closed loop behavior with the plant model and this kind of approach is called Hardwarein- the-loop simulation (HIL). In order to study and to propose some rules about the simulation of real-time systems considering HIL simulation, at the Automation Laboratory of the Centre for Mechanics and Materials Technologies of the University of Minho, Portugal – a workbench especially devoted to this study is being developed. This workbench considers an environment for Simulation, and the respective programming language, and a real controller that interacts with the simulation environment running on a PC. After looking at the available software tools and modeling languages, Dymola simulation environment and Modelica modeling language were chosen. The main reasons for this choice are associated with the unique multi-domain engineering capabilities of Dymola and Modelica that allow to deal, on the same environment, with many different engineering domains like hydraulics, power train, thermodynamics, air-conditioning, vehicle dynamics, mechanical, electrical, electronic, control, thermal, pneumatic, among others... As real controller, the choice was a Programmable Logic Controller (PLC) from OMRON company, the CPM2A model. This paper presents the first step, of this ongoing work, and is focused, mainly, on studying how to exchange information between a real PLC (used, as controller, on the designed workbench) and Dymola software that will run specific plant models, developed in Modelica language, on a Personal Computer.(undefined

Design of an adapted standing frame for rehabilitation of children with mental deficiency

A standing frame is a mechanical (old) or mechatronic (new) equipment, that has as main goal to correct the incapacity of certain individuals for assuming the body’s vertical position. The existing standing frames, on the market, do not allow easy placement of the patient on the device, do not allow full mobility (within and outside of buildings), they are not versatile, they are not modular and they do not allow children to have occupational activities during treatments. This paper presents the project of a Standing frame for use in the treatment of children with mental deficiency. The Standing frame presented in this paper takes into account the limitations mentioned above and is perfectly adapted to this very specific and very special target people. The main features of the equipment whose project is presented in this article are the modularity, easiness of placing the patient and easiness of use, especially when the patient, and family, need to travel and need to carry with them the standing frame.(undefined

Partial plant models in formal verification of industrial automation discrete systems

The use of a plant model for formal verification of Industrial Automation systems controllers must be used in order to improve the obtained results. However, if there are some cases where the use of a plant model makes the formal verification results more realistic and robust, there are other cases where this does not always happen. The discussion presented in this paper is related with the need of using a Plant Model considering, not all of the Plant Model, but Partial Plant models in order to facilitate formal verification tasks of Industrial Automation Discrete Event Systems

Supporting requirements formulation in software formal verification

Formal verification tools such as model checkers have reached a stage were their applicability in the development process of dependable and safety critical systems has become viable. While the formal verification step in tools such as model checkers is fully automated, writing appropriate models and properties is a skillful process. In particular, a correct understanding of the logics used to express properties is needed to guarantee that properties correctly encode the original requirements. In this paper we illustrate how a patterns-based tool can help in simplifying the process of generating logical formulae from informally expressed requirements

A dependable automated people mover system modeled and verified using timed automata : a case study

Automated People Movers (APM) are systems for passenger transport with fully automated operation and high frequency service. For this study we have used the system named Aeromovel installed in Porto Alegre, Brazil. Aeromovel is a non-conventional Automatic People Mover whose operation principle is based on pneumatics. This paper proposes the use, in a complementary way, of two analysis techniques, simulation and formal verification, in order to guarantee the desired behavior for an APM propulsion system composed by a centrifugal fan and ten (on-off and proportional) pneumatic valves driven by pneumatic pistons. This approach is based on the use of timed automata and UPPAAL modelchecker. The more focused aspect is the modeling of the propulsion system associated at the distributed control system. Some simulation and formal verification results are presented, considering desired behavior properties in order to improve the system’s dependability

Modeling and simulating the controller behavior of an automated people mover using IEC 61850 communication requirements

Automated People Movers (APM) are systems for passenger transport with fully automated operation and high frequency service. Trains controllers are traditionally centralized and based on wired circuits, although they generally have serious difficulties in the installation and maintenance. As there is increased demand on the system, there are advantages in choosing an open architecture, with a simple communication system and distributed. These concepts are largely addressed in the development of IEC 61850. In this study we proposed the adaptation of the standard IEC 61850, design to be used in electric power systems to be applied in an APM system named Aeromovel installed in Porto Alegre, Brazil. Aeromovel is a nonconventional Automatic People Mover whose operation principle is based on pneumatics. A model, based on timed automata formalism, is proposed for IEC 61850 communications requirements and respective simulation results are presented.Guilherme Kunz is supported by the PTI C&T program (Fundacao Parque Tecnologico Itaipu - FPTI-BR). The authors would like to thank to PTI C&T/FPTI-BR for financial support and to CESUP-UFRGS for access to the clusters

Conceptual design and development of an automated co-generation system

Co-generation or Combined Heat and Power (CHP) is the simultaneous generation of both electricity and heat from the same fuel for useful purposes. The fuel varies greatly and can include coal, biomass, natural gas, nuclear material, the sun or heat stored in the earth. Co-generation (as a vector of energy efficiency) and renewable sources of energy possess their own set of low carbon benefits. Coupling co-generation and renewable sources contribute to a very strong proposition since it leads to the supply of both low-carbon electricity and low-carbon heat. In the case of co-generation plants fuelled by renewable energy sources, the low-carbon benefits of the heat are obvious since they derive from the renewable nature of the fuel. However, this also apply in the case of plants feed by other types of fuel. Such plants produce excess heat alongside electricity. When this heat, which is an unavoidable by-product, is used to satisfy an existing heat demand carbon dioxide (CO2) emissions are reduced overall, through a more efficient use of the fuel. The distributed generation systems produce energy close to the point of use, which typically doubles the efficiency in terms of fuel input‐to‐energy output ratio compared to conventional power generation in central plants. This means that the same amount of energy can be produced with half the amount of fuel, making distributed generation an effective approach to reducing greenhouse gas emissions. According to official government reports, the creation of distributed generation systems will account for at least 5% of gas reduction. In this paper the conceptual design and development of an automated co-generation system to apply in collective residences is presented. After concluding the definition of the demanded specifications and requirements for the co-generation system it is presented and discussed the developed solution with the identification of the main components, including the selection and prototype implementation of the necessary sensors and actuators that integrate the system. It is also shown a systematized approach that consists in using the GEMMA and the SFC formalisms for the structure and specification of all the system behaviour, considering all the stop states and functioning modes of the co-generation system.(undefined

Modeling and simulation of IEC 61850 requirements applied to an automated people mover's controller

Automated People Movers (APM) are systems for passenger transport with fully automated operation and high frequency service. For this study, we proposed the adaptation of the standard IEC 61850 (design to be used in electric power systems based in intelligent electronic devices) to allow its application to an APM system named Aeromovel installed in Porto Alegre, Brazil. Aeromovel is a nonconventional Automatic People Mover whose operation principle is based on pneumatics. This paper proposes the use of two analysis techniques, Simulation and Formal Verification, in order to guarantee the desired behaviour for an APM propulsion system composed by a centrifugal fan and ten (on-off and proportional) pneumatic valves driven by pneumatic pistons. This approach is based on the use of timed automata and UPPAAL software.Guilherme Kunz is supported by the PTI C&T program (Fundacao Parque Tecnologico Itaipu - FPTI-BR). The authors would like to thank to PTI C&T/FPTI-BR for financial support and to CESUP-UFRGS for access to the clusters