Wyniki wyszukiwania - BazTech

1

Singularity-robust inverse kinematics for serial manipulators

Dulęba Ignacy

Journal of Automation Mobile Robotics and Intelligent Systems

|

2023

|

Vol. 17, No. 3

38--45

EN

This paper is a practical guideline on how to analyze and evaluate the literature algorithms of singularity- robust inverse kinematics or to construct new ones. Additive, multiplicative, and based on the Singularity Value Decomposition (SVD) methods are examined to retrieve well-conditioning of a matrix to be inverted in the Newton algorithm of inverse kinematics. It is shown that singularity avoidance can be performed in two different, but equivalent, ways: either via properly modified manipulability matrix or not allowing the decrease of the minimal singular value below a given threshold. It is discussed which method can always be used and which can only be used when some pre‐conditions are met. Selected methods are compared to with respect to the efficiency of coping with singularities based on a theoretical analysis as well as simulation results. Also, some questions important for mathematically and/or practically oriented roboticians are stated and answered.

2

Model manipulatora o strukturze szeregowej w programach Catia i Matlab

Kocurek Ł., Góra M.

Mechanik

|

2014

|

R. 87, nr 2CD

PL

W pracy opracowano modele manipulatora Fanuc S-420F o strukturze szeregowej z uwzględnieniem jego analizy kinematycznej w środowisku CATIA i Matlab. Otrzymane modele wykorzystano do generowania trajektorii robota we współrzędnych konfiguracyjnych. Wyznaczono zależności współrzędnych kartezjańskich członu roboczego względem podstawy manipulatora od czasu dla zadanego przejścia z położenia A do B. Porównano wyniki uzyskane z modeli utworzonych w środowisku CATIA i Matlab.

EN

Models of Fanuc S-420F serial manipulator for kinematic analysis were formulated in CATIA and Matlab environment. The resulting models were used to generate the manipulator trajectory in joint space. Cartesian coordinates of the robot end-effector were determined in relation to time of passing from pose A to B. The results obtained from the models created in CATIA and Matlab environments were compared.

3

A comparison of Jacobian-based methods of inverse kinematics for serial robot manipulators

Dulęba I., Opałka M.

International Journal of Applied Mathematics and Computer Science

|

2013

|

Vol. 23, no. 2

373--382

EN

The objective of this paper is to present and make a comparative study of several inverse kinematics methods for serial manipulators, based on the Jacobian matrix. Besides the well-known Jacobian transpose and Jacobian pseudo-inverse methods, three others, borrowed from numerical analysis, are presented. Among them, two approximation methods avoid the explicit manipulability matrix inversion, while the third one is a slightly modified version of the Levenberg–Marquardt method (mLM). Their comparison is based on the evaluation of a short distance approaching the goal point and on their computational complexity. As the reference method, the Jacobian pseudo-inverse is utilized. Simulation results reveal that the modified Levenberg–Marquardt method is promising, while the first order approximation method is reliable and requires mild computational costs. Some hints are formulated concerning the application of Jacobian-based methods in practice.

4

Simpliefied Collision Detection in 4r Serial Manipulators

Handke A.

Acta Mechanica et Automatica

|

2013

|

Vol. 7, no. 1

11-14

EN

This paper concerns the problem of designating criteria for assessing the possibility of a collision between the elements of serial manipulators with three rotary joints allowing to flex the segments in common plane oriented by rotating the fourth connection. The issue of contactless and efficient functioning of described group of manipulators has been considered in the spatial system. Equations were derived determining the possibility of a collision between selected segments of both manipulators. Collision detection model isn't based on the information from the tactile sensors, but only on the relative position between the segments of manipulators. Based on the parameters defining the collision, the search for method of impossible collision was set on designing level, in order to minimize the time needed to examine all possible scenarios of collisions between segments. The results were included in development of methods and algorithms for planning and controlling movements of finger modules in anthropomorphic manipulator during grasping objects of indeterminate shape.

5

Stiffness Matrix Analysis of Six-Revolute Serial Manipulator

Knapczyk J., Ryska M.

Acta Mechanica et Automatica

|

2012

|

Vol. 6, no. 2

62-65

EN

This paper presents a simple procedure that can be used to determine the stiffness matrix of 6R serial manipulator in selected points of the work space with joint stiffness coefficients taking into account. Elastokinematical model for the robot manipulator FANUC S-420F was considered as spatial and serial kinematical chain composed of six rigid links, connected by ideal revolute joint (without clearances and deformable elements), with torsion elasticity of the joint drive system (relative torsion deformations are proportional to acted torques) taking into account. Assumed model is used for displacement analysis of the end-effector for a given applied force in quasi-static condition. The analysis results are presented as Cartesian stiffness matrix of studied manipulator.