IMT Institutional Repository: No conditions. Results ordered -Date Deposited. 2024-03-28T17:34:49ZEPrintshttp://eprints.imtlucca.it/images/logowhite.pnghttp://eprints.imtlucca.it/2012-03-07T10:51:31Z2013-09-30T12:32:32Zhttp://eprints.imtlucca.it/id/eprint/1229This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/12292012-03-07T10:51:31ZA sub-optimal second order sliding mode controller for systems with saturating actuatorsIn this technical note, the problem of the possible saturation of the continuous control variable in the sub-optimal second order sliding mode controller, applied to systems with saturating actuators, is addressed. It is proved that during the sliding phase, if basic assumptions are made, the continuous control variable never saturates. On the contrary, during the reaching phase, the presence of saturating actuators can make the steering of the sliding variable to zero in a finite time not always guaranteed. In the present technical note, the original algorithm is modified in order to solve this problem: a new strategy is proposed, which proves to be able to steer the sliding variable to zero in a finite time in spite of the presence of saturating actuators.Antonella FerraraMatteo Rubagotti2012-03-06T15:10:50Z2013-09-30T12:24:26Zhttp://eprints.imtlucca.it/id/eprint/1227This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/12272012-03-06T15:10:50ZSliding mode control of a mobile robot for dynamic obstacle
avoidance based on a time-varying harmonic potential fieldIn this paper, a harmonic potential field method for dynamic environments is proposed to generate an on-line reference trajectory for a wheeled mobile robot. A sliding mode controller is used to make the robot move along the prescribed trajectory determined by the gradient lines. The potential field is modified on-line, in order to make the robot avoid the collision with obstacles which move along non a-priori known trajectories with time-varying speed. The mechanism through which the field is modified is based on the so-called ‘collision cone’ concept.Antonella FerraraMatteo Rubagotti2012-03-06T15:01:57Z2013-09-30T12:24:52Zhttp://eprints.imtlucca.it/id/eprint/1226This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/12262012-03-06T15:01:57ZGradient tracking based second order sliding mode control
of a wheeled vehicleAntonella FerraraMatteo Rubagotti2012-03-06T14:41:51Z2013-09-30T12:25:11Zhttp://eprints.imtlucca.it/id/eprint/1224This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/12242012-03-06T14:41:51ZRobust nonlinear MPC with integral sliding mode for systems with matched disturbancesMatteo RubagottiDavide Martino RaimondoAntonella FerraraLalo Magni2012-03-06T14:31:56Z2013-09-30T12:26:54Zhttp://eprints.imtlucca.it/id/eprint/1223This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/12232012-03-06T14:31:56ZA sub-optimal second order sliding mode controller for current-fed induction motorsA second order sliding mode controller for current-fed induction motors is proposed in this paper. The design of the controller is based on a reduced order model of the machine, and the control variables are non-discontinuous currents, obtained integrating a discontinuous auxiliary control signal. The phase voltages are then generated using a current regulated pulse width modulation inverter, while the rotor flux value is obtained by means of a simple observer. The convergence properties of the proposed control strategy are studied in the paper, and verified in simulation.Antonella FerraraMatteo Rubagotti2012-03-06T13:33:24Z2013-09-30T12:27:16Zhttp://eprints.imtlucca.it/id/eprint/1221This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/12212012-03-06T13:33:24ZA dynamic obstacle avoidance strategy for a mobile robot based on sliding mode controlIn this paper, a dynamic obstacle avoidance strategy for mobile robots is proposed. The strategy consists of two key elements: an on-line reference generator and a control scheme to make the robot track the reference signals so as to reach a pre-specified goal point. To generate the online reference signals, a harmonic potential field for dynamic environments is exploited. The potential field is modified on-line, in order to make the robot avoid the collision with obstacles which move along non a-priori known trajectories with timevarying speed. The proposed multi-level sliding mode controller is capable of making the robot move tracking the prescribed reference signals determined by the trajectory generator. The simulation results confirm the good performances of this approach.Antonella FerraraMatteo Rubagotti2012-03-06T13:28:10Z2013-09-30T12:25:32Zhttp://eprints.imtlucca.it/id/eprint/1220This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/12202012-03-06T13:28:10ZRobust model predictive control of continuous-time sampled-data nonlinear systems with integral sliding modeA hierarchical Nonlinear Model Predictive Control (NMPC) scheme with guaranteed Input-to-State-practical- Stability (ISpS) is proposed. The controller is formed by an Integral Sliding Mode (ISM) controller and a NMPC one. The ISM, relying on the knowledge of the nominal continuous-time model of the system and of the piecewise constant control signal generated by the NMPC produces a control action aimed at reducing the difference between the dynamics of the nominal closed-loop system and the actual evolution of the state. The NMPC in this way can be designed based on a system with reduced uncertainty. In order to prove the stability of the overall control scheme, some general Regional ISpS results for continuous-time systems are proven.Matteo RubagottiDavide Martino RaimondoAntonella FerraraLalo Magni2012-03-06T13:08:24Z2013-09-30T12:28:55Zhttp://eprints.imtlucca.it/id/eprint/1218This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/12182012-03-06T13:08:24ZOptimal disturbance rejection via integral sliding mode control for uncertain systems in regular formThis paper considers the problem of using an integral sliding mode strategy to reduce the disturbance terms acting on nonlinear systems in regular form. It is proved that the definition of a suitable sliding manifold and the generation of sliding modes upon it can guarantee the minimization of the disturbance terms. Simulation examples shows the effectiveness of the proposal.Matteo RubagottiAntonio EstradaFernando CastanosAntonella FerraraLeonid Fridman2012-03-06T12:14:28Z2013-09-30T12:28:34Zhttp://eprints.imtlucca.it/id/eprint/1217This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/12172012-03-06T12:14:28ZSecond order sliding mode control of a perturbed double integrator with state constraintsThis paper introduces a second order sliding mode controller for double integrators subject to external disturbances and model uncertainties, with both control and state constraints. The proposed control strategy proves to be able to robustly steer the system state to zero in a finite time, fulfilling the state constraints in spite of the uncertainties, provided that the initial state is inside a given region. The effectiveness of the proposal is then tested on a simulation example.Matteo RubagottiAntonella Ferrara2012-03-06T12:06:46Z2013-09-30T12:27:36Zhttp://eprints.imtlucca.it/id/eprint/1216This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/12162012-03-06T12:06:46ZA nonlinear model predictive control scheme with multirate integral sliding modeIn this paper, a hierarchical multirate control scheme for nonlinear discrete-time systems is proposed, composed of a robust model predictive controller (MPC) and a multirate integral sliding mode (MISM) controller. In particular, the MISM controller acts at a faster sampling time than the MPC controller, and reduces the effect of model uncertainties and external disturbances, in order to obtain, at the next sampling instant of the MPC controller, a value of the system state that is as close as possible to the nominal one. To obtain this result, the control variable is composed of two parts: one generated by the MPC controller, and the other by the MISM controller. The a-priori reduction of the disturbance terms turns out to be very useful in order to improve the convergence properties of the MPC controller.Matteo RubagottiDavide Martino RaimondoColin Neil JonesLalo MagniAntonella FerraraManfred Morari2012-03-05T13:49:24Z2013-09-30T12:30:10Zhttp://eprints.imtlucca.it/id/eprint/1213This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/12132012-03-05T13:49:24ZSliding mode observers for sensorless control of current-fed induction motorsThis paper presents the use of a higher order sliding mode scheme for sensorless control of induction motors. The second order sub-optimal control law is based on a reduced-order model of the motor, and produces the references for a current regulated PWM inverter. A nonlinear observer structure, based on Lyapunov theory and on different sliding mode techniques (first order, sub-optimal and super-twisting) generates the velocity and rotor flux estimates necessary for the controller, based only on the measurements of phase voltages and currents. The proposed control scheme and observers are tested on an experimental setup, showing a satisfactory performance.Daniele BulloAntonella FerraraMatteo Rubagotti2012-03-02T15:49:32Z2013-09-30T12:32:05Zhttp://eprints.imtlucca.it/id/eprint/1210This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/12102012-03-02T15:49:32ZSecond-order sliding-mode control of a mobile robot based on a harmonic potential fieldThe problem of controlling an autonomous wheeled vehicle which must move in its operative space and reach a prescribed goal point avoiding the collision with the obstacles is dealt with. To comply with the non- holonomic nature of the system, a gradient-tracking approach is followed, so that a reference velocity and orientation are suitably generated during the vehicle motion. To track such references, two control laws are designed by suitably transforming the system model into a couple of auxiliary second-order uncertain systems, relying on which second-order sliding modes can be enforced. As a result, the control objective is attained by means of a continuous control law, so that the problems due to the so-called chattering effect, such as the possible actuators wear or the induction of vibrations, typically associated with the use of sliding-mode control, are circumvented.Antonella FerraraMatteo Rubagotti2012-03-02T15:42:26Z2013-09-30T12:25:51Zhttp://eprints.imtlucca.it/id/eprint/1209This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/12092012-03-02T15:42:26ZA sub-optimal second order sliding mode controller for systems with saturating actuatorsIn this paper, the problem of the possible saturation of the continuous control variable in the sub-optimal second order sliding mode controller applied to relative degree one systems with saturating actuators is addressed. It is proved that during the sliding phase, if basic assumptions are made, the continuous control variable never saturates, while, during the reaching phase, the presence of saturating actuators can make the steering of the sliding variable to zero in finite time not always guaranteed. In the present paper, the original algorithm is modified in order to solve this problem: a new strategy is proposed, which proves to be able to steer the sliding variable to zero in a finite time in spite of the presence of saturating actuators.Antonella FerraraMatteo Rubagotti2012-03-02T15:30:33Z2013-09-30T12:33:14Zhttp://eprints.imtlucca.it/id/eprint/1208This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/12082012-03-02T15:30:33ZRobust model predictive control with integral sliding mode in continuous-time sampled-data nonlinear systemsThis paper proposes a control strategy for nonlinear constrained continuous-time uncertain systems which combines robust model predictive control (MPC) with sliding mode control (SMC). In particular, the so-called Integral SMC approach is used to produce a control action aimed to reduce the difference between the nominal predicted dynamics of the closed-loop system and the actual one. In this way, the MPC strategy can be designed on a system with a reduced uncertainty. In order to prove the stability of the overall control scheme, some general regional input-to-state practical stability results for continuous-time systems are proved.Matteo RubagottiDavide Martino RaimondoAntonella FerraraLalo Magni2012-03-02T15:10:30Z2013-09-30T12:37:32Zhttp://eprints.imtlucca.it/id/eprint/1207This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/12072012-03-02T15:10:30ZTime-optimal sliding-mode control of a mobile robot in a dynamic environmentIn this study, an original strategy to control a mobile robot in a dynamic environment is presented. The strategy consists of two main elements. The first is the method for the online trajectory generation based on harmonic potential fields, capable of generating velocity and orientation references, which extends classical results on harmonic potential fields for the case of static environments to the case when the presence of a moving obstacle with unknown motion is considered. The second is the design of sliding-mode controllers capable of making the controlled variables of the robot track in a finite minimum time both the velocity and the orientation references.Matteo RubagottiMarco L. Della VedovaAntonella Ferrara2012-03-02T14:54:31Z2013-09-30T12:37:55Zhttp://eprints.imtlucca.it/id/eprint/1206This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/12062012-03-02T14:54:31ZIntegral sliding mode control for nonlinear systems with matched and unmatched perturbationsWe consider the problem of designing an integral sliding mode controller to reduce the disturbance terms that act on nonlinear systems with state-dependent drift and input matrix. The general case of both, matched and unmatched disturbances affecting the system is addressed. It is proved that the definition of a suitable sliding manifold and the generation of sliding modes upon it guarantees the minimization of the effect of the disturbance terms, which takes place when the matched disturbances are completely rejected and the unmatched ones are not amplified. A simulation of the proposed technique, applied to a dynamically feedback linearized unicycle, illustrates its effectiveness, even in presence of nonholonomic constraints.Matteo RubagottiAntonio EstradaFernando CastanosAntonella FerraraLeonid Fridman2012-03-02T14:37:36Z2015-05-12T13:23:25Zhttp://eprints.imtlucca.it/id/eprint/1203This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/12032012-03-02T14:37:36ZModeling and control of an airbrake electro-hydraulic smart actuatorIn this paper, an accurate model of an airbrake electro-hydraulic smart actuator is obtained by physical considerations, and then different control strategies (variable-gain proportional control, PT1 control with switching integrator, and second order sub-optimal sliding mode control) are proposed and analyzed. This application is innovative in the avionic field, and is one of the first attempts to realize a fly-by-wire system for airbrakes, oriented to its immediate employment and installation on current aircraft. The project was carried on with the participation of the Italian Ministry of Defense, and was commissioned to MAG, a leading provider of integrated systems and aviation services for aerospace.Matteo RubagottiMarco CarminatiGiampiero ClementeRiccardo GrassettiAntonella Ferrara