Emanuele Galardi

Energy and wear optimisation of train longitudinal dynamics and of traction and braking systems

Traction and braking systems deeply affect longitudinal train dynamics, especially when an extensive blending phase among different pneumatic, electric and magnetic devices is required. The energy and wear optimisation of longitudinal vehicle dynamics has a crucial economic impact and involves several engineering problems such as wear of braking friction components, energy efficiency, thermal load on components, level of safety under degraded or adhesion conditions (often constrained by the current regulation in force on signalling or other safety-related subsystem). In fact, the application of energy storage systems can lead to an efficiency improvement of at least 10% while, as regards the wear reduction, the improvement due to distributed traction systems and to optimised traction devices can be quantified in about 50%. In this work, an innovative integrated procedure is proposed by the authors to optimise longitudinal train dynamics and traction and braking manoeuvres in terms of both energy and wear. The new approach has been applied to existing test cases and validated with experimental data provided by Breda and, for some components and their homologation process, the results of experimental activities derive from cooperation performed with relevant industrial partners such as Trenitalia and Italcertifer. In particular, simulation results are referred to the simulation tests performed on a high-speed train (Ansaldo Breda Emu V250) and on a tram (Ansaldo Breda Sirio Tram). The proposed approach is based on a modular simulation platform in which the sub-models corresponding to different subsystems can be easily customised, depending on the considered application, on the availability of technical data and on the homologation process of different components.

A Tool for the Simulation of Turbo-Machine Auxiliary Lubrication Plants

The reliability and safety of large turbo-machinery systems used in the oil and gas industries are heavily affected by the efficiency of the lubrication plant. In particular, hazard and operability (HAZOP) analyses are often performed using piping and instrumentation diagrams (P&ID; according to regulations in force, ISO 14617). Usually, these analyses are time-consuming and affected by potentially dangerous errors. In this work, a tool for the mono-dimensional simulation of thermal hydraulic plants is presented and applied to the analysis of safety-relevant components of compressor and pumping units, such as the lubrication circuits. Compared to known commercial products, the proposed tool is optimised for fixed step solvers in order to make real-time (RT) integration easier. The proposed tool defines a general approach, and can be used as a SimScape-Simulink library of thermal-hydraulic components (designed according to the P&ID definitions). Another interesting feature of the tool is the automatic scheme generation, where the Simulink model can be automatically generated by P&ID schemes.

Development of efficient models of Magnetic Braking Systems of railway vehicles

In modern railway vehicles, the use of Magnetic Braking Systems is continuously increasing, because they are characterized by high braking performances and low energy consumptions. Hence, the study and the accurate modelling of Magnetic Braking Systems is a very important issue, because they significantly affect the dynamics of vehicle and electrical supply circuit. Usually, the performances of Magnetic Braking Systems are evaluated on test-rigs in order to reduce times and costs of testing phases. For this reason, the authors focus on the development of a complete 3D model of Magnetic Brake System test-rig (built in COMSOL), including all the electromagnetic, circuital and mechanical parts. These parts are often studied separately in the literature; however, a combined analysis is crucial to correctly describe the behaviour of the whole system. The proposed model is highly modular (to describe different Magnetic Brake System test-rig layouts characterized by a different number of magnetic polar expansions) and aims at obtaining a compromise between accuracy and numerical efficiency. Subsequently, a second simplified lumped parameter model derived from the complete one and built in MATLAB is developed, to further reduce the computational load without decreasing the results accuracy. In this work, both the models have been developed and validated in collaboration Ferrovie dello Stato and compared with other simplified models present in the literature.

Design and testing of a pulley and cable actuator for large ball valves

The objective of this work is the development of an innovative actuator for Velan ABV S.p.A., which is mainly used for control and special on/off applications where high efficiency and linear behaviors are desirable specifications. The main performances of the proposed actuator, which has been protected by a patent, have been compared with a conventional scotch yoke one, using both the simulation results and the experimental data. In order to measure the efficiency and the dynamical response of the actuators, the authors have designed a hydraulic test rig, configured to fulfill different testing procedures. In this way, it is possible to perform both static tests to identify actuator efficiency and dynamic hardware-in-the-loop tests in which an assigned load or valve impedance function is simulated to verify the response of the tested object in realistic operating conditions. Finally, the proposed test rig has been successfully used to perform reliability and fatigue tests in which the actuator is stressed with realistic and repetitive loads. Moreover, the integrated development of both innovative actuator and testing devices is explained introducing interesting concepts whose applications are normally limited to robotics (e.g. impedance and force control) or vehicular technology (e.g. smart suspensions and suppression of vibrations).

Hardware-in-the-loop testing of bypass valve actuation system: Design and validation of a simplified real time model

During the start-up and shut-down phases of steam power plants many components are subjected to pressure and temperature transients that have to be carefully regulated both for safety and reliability reasons. For this reason, there is a growing interest in the optimization of turbine bypass controllers and actuators which are mainly used to regulate the plant during this kind of operations. In this work, a numerically efficient model for real-time simulation of a steam plant is presented. In particular, a modular Simulink™ library of components such as valves, turbines, and heaters has been developed. In this way, it is possible to easily assemble and customize models able to simulate different plants and operating scenarios. The code, which is implemented for a fixed, discrete step solver, can be easily compiled for a RT target (such as a Texas Instrument DSP) in order to be executed in real time on a low-cost industrial hardware. The proposed model has been used for quite innovative applications such as the development of a hardware-in-the-loop test rig of turbine bypass controllers and valve positioners. Preliminary experimental activities and results of the proposed test rig developed for Velan ABV are introduced and discussed.

Hardware in the loop testing of a steam turbine bypass regulator using a TI C2000 micro-controller

For a fast and safe start up and shut down of steam power plant, there is a growing interest in the optimization of turbine bypass controllers and actuators that are mainly used during transients. This work is focused on the development of a simple and fast code for real time simulation of a steam plant for the Hardware In the Loop (HIL) simulation of turbine bypass controllers and actuators. The idea is to build a Simulink library of simplified plant components such as valves, turbines, heaters and so on that could be easily assembled in order to simulate with a very simplified approach different plants and operating scenarios. The code, which is implemented for a fixed, discrete step solver should be easily compiled for a real time target such as a Texas Instrument C2000 controller (TMS320F28335 series), in order to be executed in Real Time (RT) on a low cost industrial hardware. In particular the developed code should is used for the development of a virtual environment that should be used for HIL testing of controllers and actuators.

Real-time modeling, control and optimization of turbo-machinery auxiliary plants

In the Oil & Gas industry, the testing of auxiliary lubrication plants represents a mandatory preliminary activity before the whole turbo-machinery train (including the auxiliary lubrication plant) can be put in operation. To this end, the employment of both efficient and accurate plant models becomes very important to synthesize satisfactory control strategies for both testing and normal operation purposes. This way, many benefits (e.g. in terms of safety, times and costs of execution) can be achieved. Therefore, this article focuses on the development of innovative and efficient real-time models and control architectures to describe and regulate the auxiliary lubrication systems. All the new strategies have been validated through accurate real experimental campaign and real-time hardware. According to the Bond-Graph modeling strategy, an efficient lumped parameter model of the lube oil console has been built to properly optimize the description of such system and the efficiency of the control strategies. The code has been compiled and uploaded on a commercial real-time platform that has been used to regulate the pressure control valve of the physical plant (to this aim, a new regulator has been developed). In particular, the control was designed according to a novel model-based methodology, including both identification and control optimization techniques (based on flexible simplex techniques). The comparison between the data obtained from the simulated system and the ones acquired from the physical plant shows the good agreement, reliability and efficiency of the proposed model and the control strategy. Both the modeling approach and the control strategy have been developed in collaboration with Baker and Hughes General Electric, while the experimental data were acquired in a plant located in Massa (Italy).

Control design, simulation and validation of a turbo-machinery auxiliary plant

In the oil and gas industry, the testing of auxiliary lubrication plants represents an important preliminary activity before the whole turbo machinery train (including the auxiliary lubrication plant) can be put in operation. Therefore, the employment of both efficient and accurate plant models becomes mandatory to synthesize satisfactory control strategies both for testing and normal operation purposes. For this reason, this paper focuses on the development of innovative real-time models and control architectures to describe and regulate auxiliary lubrication plants. In particular, according to the Bond-Graph modelling strategy, a novel lumped parameter model of the lube oil unit has been developed to properly optimize the behaviour of this unit if it is controlled. The code has been compiled and uploaded on a commercial real-time platform, employed to control the pressure control valve of the physical plant, for which a new controller has been developed. The comparison between the data obtained from the simulated system and acquired from the physical plant shows good agreement and the good performance and reliability of the proposed model and control strategy. The modelling approach and the control strategy have been developed in collaboration with GE Nuovo Pignone S.p.a. while the experimental data were acquired in a plant located in Ptuj (Slovenia).

Design and Testing of an Innovative Wire Transmission for a Quarter-Turn Actuator

The object of this work is the development of an innovative wire actuator in collaboration with Velan ABV S.p.A., which will be mainly used in applications in which high efficiency and linear behavior are desirable specifications. In this work, the main features of the proposed actuator, which is protected by a patent, are evaluated and compared with respect to a conventional solution consisting of a scotch yoke (SY) transmission system. The comparison is performed using both the simulation results and the experimental data. In order to identify the efficiency and the dynamical response of the innovative actuator, the authors have designed a hydraulic test rig, which can be configured to perform different testing procedures. In this way, it is possible to perform both static tests to identify actuator efficiency, and dynamic ones, in which an assigned load or a valve impedance function is simulated to verify the response of the tested actuator in realistic conditions. Finally, the proposed test rig has been successfully employed to perform both reliability and fatigue tests in which the actuator is subjected to realistic and repetitive loads.

Development and Preliminary Validation of Efficient 3D Models of Tilting Pad Journal Bearings

This paper mainly focuses on the development of efficient three-dimensional (3D) models of TPJBs, able to contemporaneously simulate both the rotor dynamics of the system and the lubricant supply plant. The proposed modelling approach tries to obtain a good compromise between the typical accuracy of standard 3D models and the high numerical efficiency of simpler and less accurate models. In this work, the whole model has been developed and validated in collaboration with Nuovo Pignone General Electric S.p.a. which provided the required technical and physical data. In particular, the experimental data are referred to a suitable lube oil console system, built at the GE testing center in Massa-Carrara (MS, Italy) for the verification of plant components.