Carlo Rossi

Speed Sensorless Control of Induction Motors Based on a Reduced-Order Adaptive Observer

A novel speed sensorless indirect field-oriented control for the full-order model of the induction motor is presented. It provides local exponential tracking of smooth speed and flux amplitude reference signals together with local exponential field orientation, on the basis of stator current measurements only and under assumption of unknown constant load torque. Speed estimation is performed through a reduced-order adaptive observer based on the torque current dynamics, while no flux estimate is required for both observation and control purposes. The absence of the flux model in the proposed algorithm allows for simple and effective time-scale separation between the speed-flux tracking error dynamics (slow subsystem) and the estimation error dynamics (fast subsystem). This property is exploited to obtain a high performance sensorless controller, with features similar to those of standard field-oriented induction motor drives. Moreover, time-scale separation and physically-based decomposition into speed and flux subsystems allow for a simple and constructive tuning procedure. The theoretical analysis based on the singular perturbation method enlightens that a persistency of excitation condition is necessary for the asymptotic stability. From a practical viewpoint, it is related to the well-known observability and instability issues due to a lack of back-emf signal at zero-frequency excitation. A flux reference selection strategy has been developed to guarantee Persistency of excitation in every operating condition. Extensive simulation and experimental tests confirm the effectiveness of the proposed approach.

Advances in Control Theory and Applications

Modeling and Control of Autonomous Helicopters.- Efficient Quantization in the Average Consensus Problem.- Human-Robot Interaction Control Using Force and Vision.- A Dissipation Inequality for the Minimum Phase Property of Nonlinear Control Systems.- Input Disturbance Suppression for Port-Hamiltonian Systems: An Internal Model Approach.- A Systems Theory View of Petri Nets.- Wireless Sensing with Power Constraints.- The Important State Coordinates of a Nonlinear System.- On Decentralized and Distributed Control of Partially-Observed Discrete Event Systems.- A Unifying Approach to the Design of Nonlinear Output Regulators.- Controller Design Through Random Sampling: An Example.- Digital Control of High Performance Power Supplies for a Synchrotron Light Source.- Distributed PCHD-Systems, from the Lumped to the Distributed Parameter Case.- Observability and the Design of Fault Tolerant Estimation Using Structural Analysis.- Robust Hybrid Control Systems: An Overview of Some Recent Results.

Asymptotic Tracking of Non Sinusoidal Periodic References: a Switched Linear Internal Model approach

Abstract The regulation theory is a very robust way to achieve the asymptotic tracking of input references on Linear Time-Invariant systems generated by an exosystem. Nevertheless, the classical regulation theory cannot be applied to the asymptotic tracking of non-sinusoidal periodic references having an infinite number of harmonics (as triangular waves). In literature many methods have been proposed to deal with this kind of problem. In this paper a novel approach based on a Switched Linear Internal Model is proposed by presenting some preliminary results. This approach seems particularly promising in terms of robustness to disturbances not “captured” by the internal model and this is the main motivation of starting this study.

Hybrid optimal control of an automated manual transmission system

Abstract In this paper, on the basis of a simplified hybrid model of an Automated Manual Transmission (AMT) system with servo-actuated clutch and gearbox, the control strategy for the gearshift is formally addressed as a hybrid optimal control problem and solved by means of numerical optimization method. The gear upshift request is performed with locked clutch and achieving the synchronization of the requested gear by exploiting engine cut-off and properly controlling the engine and the gearbox. Performance achievable with the proposed strategy under various vehicle conditions and engine regimes are shown.

On the sensitivity of a switched linear internal model controller

In this paper the Switched Linear Internal Model (SLIM) controller, an Internal Model based control scheme recently proposed by the authors, is qualitatively analyzed in terms of sensitivity to external disturbances. This investigation is particularly relevant to motivate further efforts toward a theoretical assessment of the considered scheme. In fact, SLIM solution is expected to have good robustness properties when compared with other Internal Model based scheme. A comparison with the well-known Repetitive Learning Control is discussed.

Digital Control of High Performance Power Supplies for a Synchrotron Light Source

Design and control of Power Supplies (PSs) feeding the magnets of a Synchrotron Light Source have to match severe specifications; high accuracy in the range of ppm in output current tracking is required for the correct operation of the magnets, while a Power Factor (PF) close to the unit is demanded at the input section due to the high power involved.