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G. Pajak - One of the best experts on this subject based on the ideXlab platform.

  • point to point collision free trajectory planning for mobile manipulators
    Journal of Intelligent and Robotic Systems, 2017
    Co-Authors: G. Pajak, Iwona Pajak
    Abstract:

    The collision-free trajectory planning method subject to control constraints for mobile manipulators is presented. The robot task is to move from the current configuration to a given final position in the workspace. The motions are planned in order to maximise an instantaneous manipulability measure to avoid manipulator singularities. Inequality constraints on state variables i.e. collision avoidance conditions and mechanical constraints are taken into consideration. The collision avoidance is accomplished by local perturbation of the mobile manipulator motion in the obstacles neighbourhood. The fulfilment of mechanical constraints is ensured by using a penalty function approach. The proposed method guarantees satisfying control limitations resulting from capabilities of robot actuators by applying the trajectory scaling approach. Nonholonomic constraints in a Pfaffian Form are explicitly incorporated into the control algorithm. A computer example involving a mobile manipulator consisting of nonholonomic platForm (2,0) class and 3DOF RPR type holonomic manipulator operating in a three-dimensional task space is also presented.

  • planning of a point to point collision free trajectory for mobile manipulators
    International Workshop on Robot Motion and Control, 2015
    Co-Authors: G. Pajak, Iwona Pajak
    Abstract:

    A method of planning sub-optimal trajectory for a mobile manipulator working in the environment including obstacles is presented. The robot's task is to move the end-effector from a given initial to a final position in the workspace. The motions are planned in order to maximize a manipulability measure to avoid manipulator singularities. Control and mechanical constraints are taken into consideration. The method is based on using penalty function approach and a redundancy resolution at the acceleration level. The collision avoidance is accomplished by local perturbation of the mobile manipulator motion in the neighborhoods of the obstacles. Nonholonomic constraints in a Pfaffian Form are explicitly incorporated into the control algorithm. A computer example involving a mobile manipulator consisting of nonholonomic platForm (2,0) class and DOF RPR type holonomic manipulator operating in a three-dimensional task space is also presented.

  • End-effector vibrations reduction in trajectory tracking for mobile manipulator
    'JVE International Ltd.', 2015
    Co-Authors: G. Pajak
    Abstract:

    A method of motion planning for a mobile manipulator taking into account damping the end-effector vibrations is presented. The primary task of the robot is to trace a given end-effector trajectory. The redundant degrees of freedom are used to fulfil secondary objectives such as minimisation of platForm kinetic energy and maximisation of holonomic manipulability measure, which leads to reduction of the end-effector vibrations. The method is based on Jacobian pseudo inverse at the acceleration level. Nonholonomic constraints in a Pfaffian Form are explicitly incorporated to the control algorithm. A computer example involving a mobile manipulator consisting of a nonholonomic platForm (2, 0) class and SCARA-type holonomic manipulator operating in two-dimensional task space is also presented

J. R. Villanueva - One of the best experts on this subject based on the ideXlab platform.

  • Adiabatic analysis of the rotating BTZ black hole
    'Springer Science and Business Media LLC', 2021
    Co-Authors: Mohsen Fathi, Samuel Lepe, J. R. Villanueva
    Abstract:

    In this paper we analyze some interesting features of the thermodynamics of the rotating BTZ black hole from the Carathéodory axiomatic postulate, for which, we exploit the appropriate Pfaffian Form. The allowed adiabatic transFormations are then obtained by solving the corresponding Cauchy problem, and are studied accordingly. Furthermore, we discuss the implications of our approach, regarding the second and third laws of black hole thermodynamics. In particular, the merging of two extremal black holes is studied in detail

  • Adiabatic evolution of Hayward black hole
    'Elsevier BV', 2021
    Co-Authors: Mohsen Fathi, Martín Molina, J. R. Villanueva
    Abstract:

    In this letter we use the Carathéodory's approach to thermodynamics, to construct the thermodynamic manifold of the Hayward black hole. The Pfaffian Form representing the infinitesimal heat exchange reversibly is considered to be δQrev≡drs−FHdl, previously obtained by Molina & Villanueva [1], where rs is the Schwarzschild radius, l is the Hayward's parameter responsible for the possible regularization of the Schwarzschild black hole, and FH is the intensive variable called the Hayward's force. By solving the associated Cauchy problem, the adiabatic paths are confined to the non-extremal manifold, and therefore, the status of the second and third laws are preserved. Consequently, the extremal sub-manifold corresponds to the adiabatically disconnected boundary of the manifold. In addition, the merger of two extremal Hayward black holes is analyzed

Iwona Pajak - One of the best experts on this subject based on the ideXlab platform.

  • point to point collision free trajectory planning for mobile manipulators
    Journal of Intelligent and Robotic Systems, 2017
    Co-Authors: G. Pajak, Iwona Pajak
    Abstract:

    The collision-free trajectory planning method subject to control constraints for mobile manipulators is presented. The robot task is to move from the current configuration to a given final position in the workspace. The motions are planned in order to maximise an instantaneous manipulability measure to avoid manipulator singularities. Inequality constraints on state variables i.e. collision avoidance conditions and mechanical constraints are taken into consideration. The collision avoidance is accomplished by local perturbation of the mobile manipulator motion in the obstacles neighbourhood. The fulfilment of mechanical constraints is ensured by using a penalty function approach. The proposed method guarantees satisfying control limitations resulting from capabilities of robot actuators by applying the trajectory scaling approach. Nonholonomic constraints in a Pfaffian Form are explicitly incorporated into the control algorithm. A computer example involving a mobile manipulator consisting of nonholonomic platForm (2,0) class and 3DOF RPR type holonomic manipulator operating in a three-dimensional task space is also presented.

  • planning of a point to point collision free trajectory for mobile manipulators
    International Workshop on Robot Motion and Control, 2015
    Co-Authors: G. Pajak, Iwona Pajak
    Abstract:

    A method of planning sub-optimal trajectory for a mobile manipulator working in the environment including obstacles is presented. The robot's task is to move the end-effector from a given initial to a final position in the workspace. The motions are planned in order to maximize a manipulability measure to avoid manipulator singularities. Control and mechanical constraints are taken into consideration. The method is based on using penalty function approach and a redundancy resolution at the acceleration level. The collision avoidance is accomplished by local perturbation of the mobile manipulator motion in the neighborhoods of the obstacles. Nonholonomic constraints in a Pfaffian Form are explicitly incorporated into the control algorithm. A computer example involving a mobile manipulator consisting of nonholonomic platForm (2,0) class and DOF RPR type holonomic manipulator operating in a three-dimensional task space is also presented.

Forrester, Peter J. - One of the best experts on this subject based on the ideXlab platform.

  • The limiting Kac random polynomial and truncated random orthogonal matrices
    'IOP Publishing', 2010
    Co-Authors: Forrester, Peter J.
    Abstract:

    An exact calculation of the eigenvalue statistics of truncated random Haar distributed real orthogonal matrices has recently been carried out by Khoruzhenko, Sommers and Zyczkowski. We further develop this calculation, and use it to deduce a Pfaffian Form of the correlations for the zeros of the limiting Kac random polynomial. This contrasts with the Forms known from previous studies of the real zeros (a multidimensional Gaussian integral with the integrand multiplied by the absolute values of the variables) and the complex zeros (a Hafnian).Comment: 12 pages, no figure

  • A generalized plasma and interpolation between classical random matrix ensembles
    'Springer Science and Business Media LLC', 2010
    Co-Authors: Forrester, Peter J., Sinclair, Christopher D.
    Abstract:

    The eigenvalue probability density functions of the classical random matrix ensembles have a well known analogy with the one component log-gas at the special couplings \beta = 1,2 and 4. It has been known for some time that there is an exactly solvable two-component log-potential plasma which interpolates between the \beta =1 and 4 circular ensemble, and an exactly solvable two-component generalized plasma which interpolates between \beta = 2 and 4 circular ensemble. We extend known exact results relating to the latter --- for the free energy and one and two-point correlations --- by giving the general (k_1+k_2)-point correlation function in a Pfaffian Form. Crucial to our working is an identity which expresses the Vandermonde determinant in terms of a Pfaffian. The exact evaluation of the general correlation is used to exhibit a perfect screening sum rule.Comment: 21 page

Mohsen Fathi - One of the best experts on this subject based on the ideXlab platform.

  • Adiabatic analysis of the rotating BTZ black hole
    'Springer Science and Business Media LLC', 2021
    Co-Authors: Mohsen Fathi, Samuel Lepe, J. R. Villanueva
    Abstract:

    In this paper we analyze some interesting features of the thermodynamics of the rotating BTZ black hole from the Carathéodory axiomatic postulate, for which, we exploit the appropriate Pfaffian Form. The allowed adiabatic transFormations are then obtained by solving the corresponding Cauchy problem, and are studied accordingly. Furthermore, we discuss the implications of our approach, regarding the second and third laws of black hole thermodynamics. In particular, the merging of two extremal black holes is studied in detail

  • Adiabatic evolution of Hayward black hole
    'Elsevier BV', 2021
    Co-Authors: Mohsen Fathi, Martín Molina, J. R. Villanueva
    Abstract:

    In this letter we use the Carathéodory's approach to thermodynamics, to construct the thermodynamic manifold of the Hayward black hole. The Pfaffian Form representing the infinitesimal heat exchange reversibly is considered to be δQrev≡drs−FHdl, previously obtained by Molina & Villanueva [1], where rs is the Schwarzschild radius, l is the Hayward's parameter responsible for the possible regularization of the Schwarzschild black hole, and FH is the intensive variable called the Hayward's force. By solving the associated Cauchy problem, the adiabatic paths are confined to the non-extremal manifold, and therefore, the status of the second and third laws are preserved. Consequently, the extremal sub-manifold corresponds to the adiabatically disconnected boundary of the manifold. In addition, the merger of two extremal Hayward black holes is analyzed