Wyniki wyszukiwania - BazTech

1

Comparison of curvilinear parametrization methods and avoidance of orthogonal singularities in the path following task

Dyba Filip, Mazur Alicja

Journal of Automation Mobile Robotics and Intelligent Systems

|

2023

|

Vol. 17, No. 3

46--64

EN

In this paper applications of curvilinear parametrizations (Serret–Frenet, Bishop) in the path following task have been considered. The parametrizations allow one to derive manipulator’s equations with respect to a path. The full mathematical model of the path following task involves two groups of equations, i.e., the dynamics of the manipulator and the equations obtained from the parametrization method, connected in the cascaded system. Based on those relations two path following algorithms have been designed according to the backstepping integrator method (dedicated to the cascaded systems). Depending on the chosen parametrization method the algorithms differ in requirements and performance. In the paper an in-depth analysis comparing features of both considered methods has been presented. The parametric description of a path requires projection of a robot on the path. In this article the orthogonal projection has been taken into account. It introduces a singularity in the robot description. We have proposed a new form of the orthogonal projection constraint which allows a robot to not only approach the path, but also move along it. This novelty design is an important enhancement of the algorithms used so far. The problem of partially known dynamic parameters of a robot has also been addressed. In this paper, we have shown how to apply an adaptive controller to the path following task. Theoretical considerations have been verified with a simulation study conducted for a holonomic stationary manipulator. Achieved results emphasized why it is strongly recommended to use the algorithm version with the orthogonal singularity outside the path. Moreover, the comparative analysis results may be used to select the best curvilinear parametrization method according to the considered task requirements.

2

Active 6 DoF force/torque control based on Dynamic Jacobian for free-floating space manipulator

Dyba Filip, Rybus Tomasz, Wojtunik Mateusz, Basmadji Fatina Liliana

Artificial Satellites : Journal of Planetary Geodesy

|

2023

|

Vol. 58, Special Issue 1

214--229

EN

In-orbit capture of a non-cooperative satellite will be a major challenge in the proposed servicing and active debris removal missions. The contact forces between the manipulator end-effector and the elements of the target object will occur in the grasping phase. In this paper, an active 6 Degrees of Freedom (DoF) force/torque control method for manipulator mounted on a free-floating servicing satellite is proposed. The main aim of the presented method is to balance the relation between end-effector position and force along each direction in the Cartesian space. The control law is based on the Dynamic Jacobian, which takes into account the influence of the manipulator motion on the state of the servicing satellite. The proposed approach is validated in numerical simulations with a simplified model of contact. Comparison with the classical Cartesian control shows that the active 6 DoF force/torque control method allows to obtain better positioning accuracy of the end-effector and lower control torques in manipulator joints in the presence of external forces.

3

The non-orthogonal Serret-Frenet parametrization applied to the path following problem of a manipulator with partially known dynamics

Mazur Alicja, Dyba Filip

Archives of Control Sciences

|

2023

|

Vol. 33, No. 2

339--370

EN

In this paper an application of the Serret-Frenet parametrization of a curve to the path following task is presented. This curvilinear parametrization method is used to obtain a control object description relative to the desired curve defined in the three-dimensional space. In order to derive proper equations, the innovative approach of the non-orthogonal projection of a control object on the given path is investigated. The non-orthogonal projection allows to design a global control algorithm. The proposed solution results in a cascade structure of the control system. Thus, the backstepping integrator algorithm was applied to create a control law. Due to the partial knowledge of control object dynamic parameters, an adaptive algorithm is taken into account. Theoretical considerations are confirmed with simulation study. Conducted simulations illustrated following paths at different levels of complexity by a holonomic non-redundant manipulator with a fixed base.

4

Porównanie metod parametryzacji krzywoliniowych w zadaniu śledzenia ścieżki dla manipulatora holonomicznego

Dyba Filip, Mazur Alicja

Prace Naukowe Politechniki Warszawskiej. Elektronika

|

2022

|

z. 197, t. 1

33-44

PL

W artykule rozważono zastosowanie różnych metod parametryzacji krzywoliniowych (Serreta-Freneta, Bishopa) w zadaniu śledzenia ścieżki przez stacjonarny manipulator holonomiczny. Ze względu na różnice w definicji układów lokalnych stowarzyszonych z krzywa, wynikających z zastosowania danej metody parametryzacji, można uzyskać odmienne zachowanie układu sterowania, co zostało poddane analizie w niniejszej pracy. Ponadto rozważono, w jaki sposób ograniczenia wynikające z ortogonalnego rzutowania obiektu na zadaną krzywą wpływają na realizację zadania śledzenia ścieżki. Wyprowadzone równania opisujące obiekt sterowania względem krzywej posłużyły do zaprojektowania algorytmu sterowania metodą całkowania wstecznego. Wyniki teoretyczne zostały zweryfikowane za pomocą badań symulacyjnych, na podstawie których porównano możliwości stosowania rozważanych metod parametryzacji ortogonalnej.

EN

In this paper application of curvilinear parametrizations (Serret-Frenet, Bishop) in the path following task was considered. Usage of different parametrization methods results in distinct evolution of the local frame associated with the given curve. Thus, designed control algorithms have different properties which were analysed in the article. Moreover, constraints resulting from the orthogonal projection of the control object on the desired path were taken into consideration. Equations describing the control object with respect to the given path allowed to design control algorithms with the usage of the backstepping integrator method. Theoretical considerations were verifies with simulation study. Achieved results allowed to compare applicability of different orthogonal parametrization methods in the path following task for a holonomic stationary manipulator.