Fernando Lizarralde - Academia.edu (original) (raw)
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Papers by Fernando Lizarralde
Cdc, 2001
In this paper, we consider the design of a variable structure model reference adaptive control (V... more In this paper, we consider the design of a variable structure model reference adaptive control (VS-MRAC) for plants with relative degree one without the knowledge of the sign of the plant high frequency gain. A switching method for the control signal, based on an appropriate monitoring function, is proposed. As a result, we show that after a finite number of switchings, the tracking error converges to zero at least exponentially. Interestingly enough, if the initial conditions of some states of the closed-loop system are non-zero, we show that at most one switching is needed.
Proceedings of the 2004 American Control Conference, 2004
This paper extends the application of the recently proposed satis£cing control strategy to passiv... more This paper extends the application of the recently proposed satis£cing control strategy to passive systems. The satis£cing control is based on notions of satis£cing decision theory. In this framework a set of asymptotically stabilizing control laws can be parameterized in order to obey an instantaneous cost-bene£t inequality. Using the nonlinear version of the Kalman-Yacubovitch-Popov property this technique can be extended to passive systems. To illustrate the novelty of this approach, the paper considers the attitude control problem of a rigid body.
Proceedings of the American Control Conference
An output-feedback sliding mode controller is proposed for uncertain plants with relative degree ... more An output-feedback sliding mode controller is proposed for uncertain plants with relative degree higher than one in order to achieve asymptotic exact tracking of a reference model. To compensate the relative degree, a lead filter scheme is proposed such that global stability and asymptotic exact tracking are obtained. The scheme is based on a convex combination of a linear lead filter with a robust exact differentiator, based on second order sliding modes. keywords: Sliding Mode Control, Uncertain Systems, Tracking Control, Model Reference, Exact Differentiator.
Proceedings of the American Control Conference
The problem of direct adaptive visual servoing of robot manipulators is considered. A solution is... more The problem of direct adaptive visual servoing of robot manipulators is considered. A solution is developed for image-based look-and-move visual systems to allow tracking of a desired trajectory, when both camera calibration and robot dynamics are uncertain. In order to solve the multivariable parameter adaptive problem, the recently proposed Immersion and Invariance (I&I) method is used. The scheme is then combined with a robust motion controller for the manipulator, which takes into account its uncertain nonlinear dynamics and leads to an overall stable adaptive visual servoing system. The effectiveness of the proposed strategy is illustrated through simulations and experimental results.
The I/O VS-MRAC redesign and stability analysis presented earlier for the case of plants with rel... more The I/O VS-MRAC redesign and stability analysis presented earlier for the case of plants with relative degree n 2 (ACC'92), is generalized to the case of arbitrary n. The redesign is based on the explicit consideration of input disturbances which, in addition to actual external disturbances, may include the disturbance originated by the uncertainty of the plant high frequency gain (HFG). This leads to considerably simpler and less restrictive stability analysis, as well as to more e ective controller design for external disturbance rejection. It is shown that the overall error system is globally exponentially stable with respect to some small residual set, in agreement with the remarkable performance exhibited by the proposed controller. Simpli ed I/O VS-MRAC schemes are also discussed.
A class of iterative methods have recently been proposed for the path planning of nonholonomic sy... more A class of iterative methods have recently been proposed for the path planning of nonholonomic systems. These methods warp an initial path iteratively to an acceptable nal path by using Newton-Raphson or Gradient type of algorithms. Once a path is found o-line, a feedback controller is then used to follow the path. In this paper, we propose a modi cation of these o {line methods to transform them directly into a feedback controller. The main idea is to couple the iteration variable to the actual time, thus the control is executed during the path iteration, before the convergence. We show that this scheme guarantees the closed loop asymptotic stability when the system model is known, and possesses certain robustness when the model information is imperfect. By using interior penalty functions, inequality constraints can also be handled by the algorithm. Simulation results are included, showing promise of the approach.
524 -sala 5036A -20559-900 -Rio de Janeiro -RJ -Brasil RESUMO -Este artigo descreve detalhadament... more 524 -sala 5036A -20559-900 -Rio de Janeiro -RJ -Brasil RESUMO -Este artigo descreve detalhadamente a modelagem da dinâmica de veículos submarinos de operação remota (ROVs). Apresenta-se um simulador desenvolvido para ROVs denominado SOL (Simulador On-Line). Vários tópicos relacionados ao modelo dinâmico utilizado na implementação deste simulador, e não tratados adequadamente na literatura, são aqui revisados. Uma parte substancial deste trabalho é dedicada à descrição detalhada do procedimento utilizado para a identificação do modelo dinâmico dos propulsores, a partir de testes experimentais em tanque de água. Para comprovar o realismo alcançado com o SOL, são apresentadas algumas simulações e seus resultados são comparados com os resultados obtidos experimentalmente com um ROV numa piscina, nas mesmas condições.
In this work, the adaptive control of nonlinear visual servoing systems is considered. The strate... more In this work, the adaptive control of nonlinear visual servoing systems is considered. The strategy is developed for eye-to-hand systems to perform positioning and tracking tasks on the 3D environment, when both camera calibration and robot parameters are uncertain. An image-based linearization method is introduced to deal with the nonlinear control problem generated by a time-varying depth. The positioning controller is then designed by using the recently proposed Immersion and Invariance (I&I) method, whereas the Symmetric-Diagonal-Upper (SDU) factorization method is adopted to solve the adaptive multivariable tracking control problem. The overall positioning/tracking controller is first developed for the cartesian robot case, and then extended to the general case. Simulation results are also presented for the proposed strategy.
This work presents a new design concept for a remotely operated vehicle aimed to perform inspecti... more This work presents a new design concept for a remotely operated vehicle aimed to perform inspection tasks in flooded tunnels and dams. Depth and yaw controllers were developed to regulate the vehicle position in front of target area in the wall. Video cameras and sonar are used to detect disruptions in the walls or accumulated debris. Experimental results are presented to illustrate the performance and viability of the proposed controllers.
: In this paper a dynamic positioning system (DP) of remotely operated underwater vehicles (ROV&a... more : In this paper a dynamic positioning system (DP) of remotely operated underwater vehicles (ROV's) is proposed. The main blocks of the DP are described: the position measurement system; the data acquisition system; the DP=ROV interface; the control algorithm. A ...
This paper describes the development of a prototype ROV dynamic positioning (DP) system based on ... more This paper describes the development of a prototype ROV dynamic positioning (DP) system based on a Passive Arm (PA). The PA consists of a freely moving mechanical arm, without actuators, which measures the ROV position relative to some underwater structure. This measuring method was selected as the most adequate one for ROV DP when the tasks to be performed are limited to a workspace of a few meters range. A prototype passive arm based DP system was designed, constructed and tested on an actual ROV. Details about the hardware and software of the overall DP system are described.
524 -sala 5036A -20559-900 -Rio de Janeiro -RJ -Brasil RESUMO -Este artigo descreve detalhadament... more 524 -sala 5036A -20559-900 -Rio de Janeiro -RJ -Brasil RESUMO -Este artigo descreve detalhadamente a modelagem da dinâmica de veículos submarinos de operação remota (ROVs). Apresenta-se um simulador desenvolvido para ROVs denominado SOL (Simulador On-Line). Vários tópicos relacionados ao modelo dinâmico utilizado na implementação deste simulador, e não tratados adequadamente na literatura, são aqui revisados. Uma parte substancial deste trabalho é dedicada à descrição detalhada do procedimento utilizado para a identificação do modelo dinâmico dos propulsores, a partir de testes experimentais em tanque de água. Para comprovar o realismo alcançado com o SOL, são apresentadas algumas simulações e seus resultados são comparados com os resultados obtidos experimentalmente com um ROV numa piscina, nas mesmas condições.
Cdc, 2001
In this paper, we consider the design of a variable structure model reference adaptive control (V... more In this paper, we consider the design of a variable structure model reference adaptive control (VS-MRAC) for plants with relative degree one without the knowledge of the sign of the plant high frequency gain. A switching method for the control signal, based on an appropriate monitoring function, is proposed. As a result, we show that after a finite number of switchings, the tracking error converges to zero at least exponentially. Interestingly enough, if the initial conditions of some states of the closed-loop system are non-zero, we show that at most one switching is needed.
Proceedings of the 2004 American Control Conference, 2004
This paper extends the application of the recently proposed satis£cing control strategy to passiv... more This paper extends the application of the recently proposed satis£cing control strategy to passive systems. The satis£cing control is based on notions of satis£cing decision theory. In this framework a set of asymptotically stabilizing control laws can be parameterized in order to obey an instantaneous cost-bene£t inequality. Using the nonlinear version of the Kalman-Yacubovitch-Popov property this technique can be extended to passive systems. To illustrate the novelty of this approach, the paper considers the attitude control problem of a rigid body.
Proceedings of the American Control Conference
An output-feedback sliding mode controller is proposed for uncertain plants with relative degree ... more An output-feedback sliding mode controller is proposed for uncertain plants with relative degree higher than one in order to achieve asymptotic exact tracking of a reference model. To compensate the relative degree, a lead filter scheme is proposed such that global stability and asymptotic exact tracking are obtained. The scheme is based on a convex combination of a linear lead filter with a robust exact differentiator, based on second order sliding modes. keywords: Sliding Mode Control, Uncertain Systems, Tracking Control, Model Reference, Exact Differentiator.
Proceedings of the American Control Conference
The problem of direct adaptive visual servoing of robot manipulators is considered. A solution is... more The problem of direct adaptive visual servoing of robot manipulators is considered. A solution is developed for image-based look-and-move visual systems to allow tracking of a desired trajectory, when both camera calibration and robot dynamics are uncertain. In order to solve the multivariable parameter adaptive problem, the recently proposed Immersion and Invariance (I&I) method is used. The scheme is then combined with a robust motion controller for the manipulator, which takes into account its uncertain nonlinear dynamics and leads to an overall stable adaptive visual servoing system. The effectiveness of the proposed strategy is illustrated through simulations and experimental results.
The I/O VS-MRAC redesign and stability analysis presented earlier for the case of plants with rel... more The I/O VS-MRAC redesign and stability analysis presented earlier for the case of plants with relative degree n 2 (ACC'92), is generalized to the case of arbitrary n. The redesign is based on the explicit consideration of input disturbances which, in addition to actual external disturbances, may include the disturbance originated by the uncertainty of the plant high frequency gain (HFG). This leads to considerably simpler and less restrictive stability analysis, as well as to more e ective controller design for external disturbance rejection. It is shown that the overall error system is globally exponentially stable with respect to some small residual set, in agreement with the remarkable performance exhibited by the proposed controller. Simpli ed I/O VS-MRAC schemes are also discussed.
A class of iterative methods have recently been proposed for the path planning of nonholonomic sy... more A class of iterative methods have recently been proposed for the path planning of nonholonomic systems. These methods warp an initial path iteratively to an acceptable nal path by using Newton-Raphson or Gradient type of algorithms. Once a path is found o-line, a feedback controller is then used to follow the path. In this paper, we propose a modi cation of these o {line methods to transform them directly into a feedback controller. The main idea is to couple the iteration variable to the actual time, thus the control is executed during the path iteration, before the convergence. We show that this scheme guarantees the closed loop asymptotic stability when the system model is known, and possesses certain robustness when the model information is imperfect. By using interior penalty functions, inequality constraints can also be handled by the algorithm. Simulation results are included, showing promise of the approach.
524 -sala 5036A -20559-900 -Rio de Janeiro -RJ -Brasil RESUMO -Este artigo descreve detalhadament... more 524 -sala 5036A -20559-900 -Rio de Janeiro -RJ -Brasil RESUMO -Este artigo descreve detalhadamente a modelagem da dinâmica de veículos submarinos de operação remota (ROVs). Apresenta-se um simulador desenvolvido para ROVs denominado SOL (Simulador On-Line). Vários tópicos relacionados ao modelo dinâmico utilizado na implementação deste simulador, e não tratados adequadamente na literatura, são aqui revisados. Uma parte substancial deste trabalho é dedicada à descrição detalhada do procedimento utilizado para a identificação do modelo dinâmico dos propulsores, a partir de testes experimentais em tanque de água. Para comprovar o realismo alcançado com o SOL, são apresentadas algumas simulações e seus resultados são comparados com os resultados obtidos experimentalmente com um ROV numa piscina, nas mesmas condições.
In this work, the adaptive control of nonlinear visual servoing systems is considered. The strate... more In this work, the adaptive control of nonlinear visual servoing systems is considered. The strategy is developed for eye-to-hand systems to perform positioning and tracking tasks on the 3D environment, when both camera calibration and robot parameters are uncertain. An image-based linearization method is introduced to deal with the nonlinear control problem generated by a time-varying depth. The positioning controller is then designed by using the recently proposed Immersion and Invariance (I&I) method, whereas the Symmetric-Diagonal-Upper (SDU) factorization method is adopted to solve the adaptive multivariable tracking control problem. The overall positioning/tracking controller is first developed for the cartesian robot case, and then extended to the general case. Simulation results are also presented for the proposed strategy.
This work presents a new design concept for a remotely operated vehicle aimed to perform inspecti... more This work presents a new design concept for a remotely operated vehicle aimed to perform inspection tasks in flooded tunnels and dams. Depth and yaw controllers were developed to regulate the vehicle position in front of target area in the wall. Video cameras and sonar are used to detect disruptions in the walls or accumulated debris. Experimental results are presented to illustrate the performance and viability of the proposed controllers.
: In this paper a dynamic positioning system (DP) of remotely operated underwater vehicles (ROV&a... more : In this paper a dynamic positioning system (DP) of remotely operated underwater vehicles (ROV's) is proposed. The main blocks of the DP are described: the position measurement system; the data acquisition system; the DP=ROV interface; the control algorithm. A ...
This paper describes the development of a prototype ROV dynamic positioning (DP) system based on ... more This paper describes the development of a prototype ROV dynamic positioning (DP) system based on a Passive Arm (PA). The PA consists of a freely moving mechanical arm, without actuators, which measures the ROV position relative to some underwater structure. This measuring method was selected as the most adequate one for ROV DP when the tasks to be performed are limited to a workspace of a few meters range. A prototype passive arm based DP system was designed, constructed and tested on an actual ROV. Details about the hardware and software of the overall DP system are described.
524 -sala 5036A -20559-900 -Rio de Janeiro -RJ -Brasil RESUMO -Este artigo descreve detalhadament... more 524 -sala 5036A -20559-900 -Rio de Janeiro -RJ -Brasil RESUMO -Este artigo descreve detalhadamente a modelagem da dinâmica de veículos submarinos de operação remota (ROVs). Apresenta-se um simulador desenvolvido para ROVs denominado SOL (Simulador On-Line). Vários tópicos relacionados ao modelo dinâmico utilizado na implementação deste simulador, e não tratados adequadamente na literatura, são aqui revisados. Uma parte substancial deste trabalho é dedicada à descrição detalhada do procedimento utilizado para a identificação do modelo dinâmico dos propulsores, a partir de testes experimentais em tanque de água. Para comprovar o realismo alcançado com o SOL, são apresentadas algumas simulações e seus resultados são comparados com os resultados obtidos experimentalmente com um ROV numa piscina, nas mesmas condições.