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In this work, we propose a design strategy for adaptive control of a class of nonlinear systems with input and state constraints. The systems of interest are required to have relative degree 1 and a convergent zero-dynamics: these... more
In this work, we propose a design strategy for adaptive control of a class of nonlinear systems with input and state constraints. The systems of interest are required to have relative degree 1 and a convergent zero-dynamics: these properties cover a significant number of applications, after suitable changes of coordinates and with a proper selection of the regulated output. Through a design based on Barrier Lyapunov Functions, inspired by Explicit Reference Governors, we propose a feasible closed-form right-inverse unit that can be effectively interconnected with a nominal adaptive stabilizer, this way enforcing constraint satisfaction, while rejecting the effects of parametric uncertainties at the same time. The stability and feasibility properties of the control scheme are formally proven, and verified in a detailed numerical simulation.
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Power electronic converters are extensively adopted for the solution of timely issues, such as power quality improvement in industrial plants, energy management in hybrid electrical systems, and control of electrical generators for... more
Power electronic converters are extensively adopted for the solution of timely issues, such as power quality improvement in industrial plants, energy management in hybrid electrical systems, and control of electrical generators for renewables. Beside nonlinearity, this systems are typically characterized by hard constraints on the control inputs, and sometimes the state variables. In this respect, control laws able to handle input saturation are crucial to formally characterize the systems stability and performance properties. From a practical viewpoint, a proper saturation management allows to extend the systems transient and steady-state operating ranges, improving their reliability and availability. The main topic of this thesis concern saturated control methodologies, based on modern approaches, applied to power electronics and electromechanical systems. The pursued objective is to provide formal results under any saturation scenario, overcoming the drawbacks of the classic solu...
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A novel approach is proposed to compare Brushless DC control and Field Oriented Control performance in driving Permanent Magnet Synchronous Machines for multirotor UAVs, a particular class of small-size electrically-powered UAVs. Both... more
A novel approach is proposed to compare Brushless DC control and Field Oriented Control performance in driving Permanent Magnet Synchronous Machines for multirotor UAVs, a particular class of small-size electrically-powered UAVs. Both power efficiency and output torque quality are analyzed in depth to carry out causes and consequences of control issues in both cases. Power losses and torque ripple contributions, due to driving techniques and converter non idealities, are decoupled and then exploited to show how large the torque oscillations are in case of Brushless DC control, and to highlight the higher efficiency given by Field Oriented Control, which can be exploited for enhancing the flight endurance.
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Control system design is a crucial point in modern automation systems, involving an increasingly broader set of activities being performed by software. Despite the availability of several domain-specific facilities, designers daily face... more
Control system design is a crucial point in modern automation systems, involving an increasingly broader set of activities being performed by software. Despite the availability of several domain-specific facilities, designers daily face kindred issues which actually lack reference patterns, in particular as regards the architectural organization of the control logic. In this paper we present an approach that, focusing on cross-cutting domain problems and suitably abstracting from application-specific details, leads to an effective decoupling of high-level control policies from low-level actuation and sensing mechanisms. Logic Device Agents emerge as generally applicable active components modeling the behavior of commonly used field devices, which can be profitably exploited to enhance software design quality and productivity.
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Research Interests: Engineering and Elsevier
ABSTRACT High-end multicore processors are characterized by high power density with significant spatial and temporal variability. This leads to power and temperature hot-spots, which may cause non-uniform ageing and accelerated chip... more
ABSTRACT High-end multicore processors are characterized by high power density with significant spatial and temporal variability. This leads to power and temperature hot-spots, which may cause non-uniform ageing and accelerated chip failure. These critical issues can be tackled on-line by closed-loop thermal and reliability management policies. Model predictive controllers (MPC) outperform classic feedback controllers since they are capable of minimizing a cost function while enforcing safe working temperature. Unfortunately basic MPC controllers rely on a-priori knowledge of multicore thermal model and their complexity exponentially grows with the number of controlled cores. In this paper we present a scalable, fully-distributed, energy-aware thermal management solution. The model-predictive controller complexity is drastically reduced by splitting it in a set of simpler interacting controllers, each allocated to a core in the system. Locally, each node selects the optimal frequency to meet temperature constraints while minimizing the performance penalty and system energy. Global optimality is achieved by letting controllers exchange a limited amount of information at run-time on a neighbourhood basis. We address model uncertainty by supporting learning of the thermal model with a novel distributed self-calibration approach that matches well the controller architecture.
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Research Interests: Engineering, Applied Mathematics, Computer Science, Modeling, Motor Control, and 12 moreControl Systems, Instability, Orientation, Observability, Singular perturbation problems, Operant Conditioning, Electromotive Force, Tracking Error, Asymptotic Stability, Electrical And Electronic Engineering, Speed Control, and Field oriented control
Research Interests: Engineering, Applied Mathematics, Computer Science, System Identification, Parameter estimation, and 11 moreAdaptive Systems, Identification, IEEE, Commissioning, Steady state, Saturation Magnetization, Batch Process, Magnetic Saturation, Electrical And Electronic Engineering, Magnetic Flux, and Least squares method
Research Interests: Applied Mathematics, Robust control, Automotive Industry, Automotive Engineering, DYNAMIC POSITIONING, and 9 morePosition Control, Variable Structure Control, Cascade Control, Sliding Mode, Optimal Control Problem, Boolean Satisfiability, Electrical And Electronic Engineering, Control Algorithm, and Variable structure
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ABSTRACT The thermal wall for many-core systems on-chip calls for advanced management techniques to maximize performance, while capping temperatures. Distributed and compact thermal models are a cornerstone for such techniques. System... more
ABSTRACT The thermal wall for many-core systems on-chip calls for advanced management techniques to maximize performance, while capping temperatures. Distributed and compact thermal models are a cornerstone for such techniques. System identification methodologies allow to extract models directly from the target device thermal response. Unfortunately, standard Auto-Regressive eXogenous models and Least Squares techniques cannot effectively tackle both model approximation and measurement noise typical of real systems. In this work, we propose a novel distributed identification strategy to derive distributed interacting thermal models. The presented method can cope with both process noise and temperature sensor noise affecting inputs and outputs of the adopted models. Online and offline versions are presented, and issues related to model order, sampling time and input stimuli are addressed. The proposed method is applied to the Intel's Single-chip-Cloud-Computer many-core prototype.
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Research Interests: Engineering, Topology, Robust control, Nonlinear Control, Mathematical Sciences, and 15 moreAutomatica, Control Design, Reactive Power, Singular perturbation problems, Electric Current, Harmonic, Voltage, Control Strategy, Boost Converter, Active Filter, Output Voltage Regulation, Voltaje, Non Linear Control, Shunt Active Filter, and Output Regulation
ABSTRACT JOURNAL CODE: E220088 The journal it is new, but having immediately a lot of submission of invited selected articles. The paper are selected and invited on the basis of paper presented in IFAC conferences (for automatic control... more
ABSTRACT JOURNAL CODE: E220088 The journal it is new, but having immediately a lot of submission of invited selected articles. The paper are selected and invited on the basis of paper presented in IFAC conferences (for automatic control field), modified at least of 50%. The journal focuses on experimental robotics and encourages publication of work that has both theoretical and practical significance. Authors are encouraged to implement their work and demonstrate its utility on significant problems.
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To define a team for project development: - fill the form given by the teacher during classes on codesys description - or, if you have not attended the above-mentioned classes, send an e-mail to the teacher, specifying the team members... more
To define a team for project development: - fill the form given by the teacher during classes on codesys description - or, if you have not attended the above-mentioned classes, send an e-mail to the teacher, specifying the team members (surname, name, university code); up to three members for each team are allowed. Members of the teams are recommended to present the project together. The final mark on project discussion (not the global mark) will be the same for all the members. The teacher will ask to describe the project to all the members. If some of them do not answer correctly, the marks of all the members will be affected. In order to check what project has been assigned to your team (1-elevator; 2-washing-machine) please follow this link: http://www-lar.deis.unibo.it/people/atilli/files/ing-tecn/codesys/Gruppi_2010_11.pdf
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Prognostics and Health Management of machine devices and parts is a hot topic in the Industry 4.0 era. In this fashion, automated procedures to evaluate machinery working conditions are essential to minimize downtime and maintenance... more
Prognostics and Health Management of machine devices and parts is a hot topic in the Industry 4.0 era. In this fashion, automated procedures to evaluate machinery working conditions are essential to minimize downtime and maintenance costs. In this work, we study how to monitor the decrease in performance of a paper sheet feeder for the packaging industry under heavy-duty cycle operations. The main measurable outcome of such degradation is the increase in backlash among the device moving components. A wide variety of methods and procedures is available to tackle this monitoring problem. In this paper, we analyze the use of a simple yet efficient diagnosis methodology that can exploit machinery controllers (i.e., Programmable Logic Controllers) edge-computing capabilities. Vibration measurements are known in the literature to retain information about the system's mechanics. Model-of Signals, a data-driven approach based on black box system identification, allows to extract that in...
The only difference between 03b and 03 versions is that in the former the new slides on Thermocouples are in English.
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Bearings are one of the most common components in automatic machines. Diagnosis and prognosis of their working condition is crucial for minimization of downtime and maintenance costs. Different approaches may be adopted to either solve or... more
Bearings are one of the most common components in automatic machines. Diagnosis and prognosis of their working condition is crucial for minimization of downtime and maintenance costs. Different approaches may be adopted to either solve or mitigate the problem of identifying incipient faults during machinery operations. In this paper, we propose a simple and efficient yet effective method to solve this problem by exploiting the edge-computing capabilities of PLCs. Accelerometer signals are modeled as AutoRegressive (AR) processes whose coefficient are used as features for machine learning, based on logistic regression algorithm (LR), to perform Fault Detection and Isolation (FDI). Estimation and prediction are both implementable on-board the PLC, while machine learning can be carried out remotely, in a cloud computing perspective. The exploitation of AR modelling gives a simple and inherent methodology for feature selection. We apply the procedure to the Case Western Reserve University database, a widely known and used benchmark, to highlight its performance with respect to similar fault recognition techniques.
This work aims to provide useful insights into the course of action and the challenges faced by machine manufacturers when dealing with the actual application of Prognostics and Health Management procedures in industrial environments.... more
This work aims to provide useful insights into the course of action and the challenges faced by machine manufacturers when dealing with the actual application of Prognostics and Health Management procedures in industrial environments. Taking into account the computing capabilities and connectivity of the hardware available for smart manufacturing, we propose a particular solution that allows meeting one of the essential requirements of intelligent production processes, i.e., autonomous health management. Indeed, efficient and fast algorithms, that does not require a high computational cost and can be appropriately performed on machine controllers, i.e., on edge, are combined with others, which can handle large amounts of data and calculations, executed on remote powerful supervisory platforms, i.e., on the cloud. In detail, new condition monitoring algorithms based on Model-of-Signals techniques are developed and implemented on local controllers to process the raw sensor readings an...
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In this article, we introduce an easy-to-implement sensorless controller specifically designed for the regulation of the propellers of unmanned aerial vehicles (UAVs). As motivation, we present a comparison of the usual motor control... more
In this article, we introduce an easy-to-implement sensorless controller specifically designed for the regulation of the propellers of unmanned aerial vehicles (UAVs). As motivation, we present a comparison of the usual motor control architectures, i.e., field-oriented control (FOC) and brushless DC (BLDC) control, with special attention to the typical back-electromotive force shapes found in this application. In particular, we show that the adoption of sensorless FOC provides several advantages, both from the efficiency and the signal quality viewpoints, provided that accurate rotor position reconstruction is available. Therefore, a recently proposed observer is integrated into a nested FOC architecture, with formal stability guarantees and low computational effort, making the resulting strategy suitable for implementation in embedded computing systems. The algorithm is then compared experimentally to a sensorless BLDC controller and a high-end commercial drive, thus validating the previous results and showing effective time-varying speed tracking, as required for precise aggressive maneuvering. These features of efficiency, accuracy, and simplicity might prove instrumental in bolstering the introduction of a novel class of high-performance, robust UAV sensorless controllers in the forthcoming years.
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Abstract A hydraulic actuated clutch control system for commercial cars is analyzed. A physical model of the system is firstly derived: this model is then used both to define a closed loop controller, through derivation of a simplified... more
Abstract A hydraulic actuated clutch control system for commercial cars is analyzed. A physical model of the system is firstly derived: this model is then used both to define a closed loop controller, through derivation of a simplified model, and to asses the dependencies of the closed loop system performances on some plant and controller key parameters. Trade-off curves are derived that link the required performances, namely response speed and tracking error, to this key parameters. It is shown how this curves can be used to fix the specifications for both plant configuration and electronic control unit in an optimized way, in order to achieve guaranteed performances at minimum system cost.
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Abstract Control of an electrohydraulic servo-actuated clutch for an automatic gear-shifting system for commercial cars is considered. A simplified model, which takes into account the fundamental behavior of the system, is mandatory for... more
Abstract Control of an electrohydraulic servo-actuated clutch for an automatic gear-shifting system for commercial cars is considered. A simplified model, which takes into account the fundamental behavior of the system, is mandatory for the design of the clutch control. The clutch position tracking controller, designed in the framework of backstepping technique, is based on a cascade structure with nested position, speed and pressure control loops. Feed-forward terms obtained through model inversion increase the dynamic performances, while closed-loop regulators provide robustness with respect to model uncertainties. In the controller design, nonlinearities of the mechanical actuator and of the servovalve are taken into account in order to improve achievable performances. The controller behavior during tracking of smooth position references has been experimentally tested.
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In this work, stability properties of a novel and easy-to-implement sensorless observer for induction motors are investigated. The considered solution is inspired by phase-locked-loop strategies and it takes advantage from the rotor flux... more
In this work, stability properties of a novel and easy-to-implement sensorless observer for induction motors are investigated. The considered solution is inspired by phase-locked-loop strategies and it takes advantage from the rotor flux derivatives to define a rotating vector to align with, even if such variables are not directly measured. Input-to-State Stability properties are proven for suitably defined electrical and magneto-mechanical observation-error subsystems. Time scale separation is, then, exploited to invoke Singular Perturbation arguments and guarantee boundedness of the observation errors trajectories. Finally, the Small Gain Theorem is adopted to prove semiglobal uniform asymptotic stability of the presented scheme. Some additional interesting properties are discussed, beside the “main stream” of the proposed analysis. Simulations indicate the observer can be profitably exploited for induction machines speed sensorless control applications.
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In recent papers, the authors proposed a novel control approach based on the use of a Switching Linear Internal Model (SLIM) to cope with asymptotic tracking of a significant class of periodic references for “real world” applications,... more
In recent papers, the authors proposed a novel control approach based on the use of a Switching Linear Internal Model (SLIM) to cope with asymptotic tracking of a significant class of periodic references for “real world” applications, while guaranteeing good robustness properties with respect to disturbances. In the path toward a final assessment of this methodology, the problem of observing the state of the particular class of exosystems considered appears to be crucial. In this paper previous results on this topic are revised and widely extended to establish a rigorous and effective design procedure.