scholarly journals TEST SIMULATION OF «FINITE ROTATION AND DISPLACEMENT» METHOD BY THE EUROPEAN ROBOTIC ARM PASSING THROUGH THE SINGULAR POINTS

2019 ◽  
pp. 128-138
Author(s):  
А. Данилов ◽  
A. Danilov
Keyword(s):  
Singular Points ◽  
Vector Model ◽  
Robotic Arm ◽  
Structural Constraints ◽  
Finite Rotation ◽  
Displacement Method ◽  
Generalized Coordinates ◽  
Sequential Structure ◽  
Source Data ◽  
The Given

The article consider the test simulation of the «finite rotation and displacement» method (FRDM) when the European Robotic Arm (ERA) manipulator is passing through the singular points. The test simulation confirms the method’s efficiency when passing through singular points and shows how to control the manipulator with various manifestations of the singularity. Depending on the type of singularities manifestation the manipulator is controlled in the vicinity of the singular point by means of small changes in its configuration or by limiting and setting specific values to generalized coordinates at the software and hardware level. The FRDM method is designed to solve the inverse kinematics (IK) for sequential-structure manipulators with an arbitrary number of links connected by fifth-class kinematic pairs. The method is based on determining the exact and optimal iterative steps that provide the maximum approximation to the given parameters of the final link for each degree of mobility. The software has been developed that consists of subprograms for organizing a general solution of the IK and a particular one for a particular manipulator in the form of source data according to the algorithm of the method. The initial data are the vector model of the manipulator, the values of the structural constraints of the generalized coordinates and signs of kinematic pairs by type and class.

scholarly journals APPLICATION OF THE “FINITE ROTATION AND DISPLACEMENT” METHOD TO CONTROL THE PARABOLIC ANTENNA

2019 ◽  
pp. 162-169
Author(s):  
A. Danilov
Keyword(s):  
Vector Model ◽  
Small Displacement ◽  
Structural Constraints ◽  
Finite Rotation ◽  
Displacement Method ◽  
Generalized Coordinates ◽  
Sequential Structure ◽  
Parabolic Antenna ◽  
Source Data ◽  
Rotation Plane

The article deals with the application of the "finite rotation and displacement" method (FRDM) which can find the desired values of the generalized coordinates for the control system of a parabolic antenna. The special manipulator of a sequential structure with sufficient rigidity is used to control the parabolic antenna. The rigidity of this manipulator is ensured by use of links in the form of spherical shells and bearings located along the perimeter of each shell in the rotation plane of each link. It allows to optimally place the material of the manipulator's design and to obtain sufficient rigidity with minimal weight. The manipulator consists of four links connected by fifth class kinematic pairs with an arbitrary inclination of the axes. For this task the antenna's orientation is important without taking into account the small displacement of its position during the process of its orientation. The FRDM method provides both orientation and position. It is based on determining the precise and optimal iterative steps for each degree of mobility, providing maximum approximation to the specified orientation parameters of the parabolic antenna. According to the method's algorithm, the software is developed consisting of subprograms for organizing a general solution of the inverse kinematics for an arbitrary number of links and a particular one for a manipulator in the form of source data. The initial data are the vector model of the manipulator, the values of the structural constraints of the generalized coordinates, and the characteristics of kinematic pairs by type and class

Registration of the given vortex in an array of randomly placed singular points

2021 ◽  
Author(s):  
Feodor Kanev ◽  
Nailya A. Makenova ◽  
Igor Veretekhin
Keyword(s):  
Singular Points ◽  
The Given

scholarly journals АНАЛИЗ УДЕРЖИВАЮЩИХ УСИЛИЙ СХВАТА МАНИПУЛЯТОРА

World Science ◽  
2019 ◽  
Vol 1 (11(51)) ◽  
pp. 10-15
Author(s):  
Ащепкова Н. С.
Keyword(s):  
Inverse Problem ◽  
Outer Surface ◽  
Generalized Coordinates ◽  
Complex Part ◽  
Nodal Points ◽  
Gripping Force ◽  
The Given

The technological section of manufacturing a complex part is considered, the robot is used to perform auxiliary operations. The trajectory of the manipulator contains the nodal points S0, ..., S6.At points S0, ..., S6, it is necessary to provide a gripping force so that the manipulation object does not slip out of the gripping device. In this case, it is impossible to damage the outer surface of the part, which is contact while assembling the product. In addition, it is necessary to take into account the change in the shape and diameter of the workpiece both within the assortment of typical parts and during processing.The inverse problem of the manipulator’s position at the nodal points of the trajectory S0, ..., S6 is solved; the coordinates, velocities and accelerations of the gripping pole are determined at the nodal points of the trajectory S0, ..., S6 when implementing the given laws of change in the generalized coordinates; the values of the necessary holding force of the grip at the nodal points of the trajectory S0, ..., S6 are calculated.The analysis of the necessary holding forces of the grip allows to determine the gripping force, during the simulation of the manipulator's movement. This gripping force will ensure reliable fixation of the part in the gripper without damaging its outer surface.

scholarly journals Deep Reinforcement Learning with Interactive Feedback in a Human–Robot Environment

2020 ◽  
Vol 10 (16) ◽  
pp. 5574 ◽  
Author(s):  
Ithan Moreira ◽  
Javier Rivas ◽  
Francisco Cruz ◽  
Richard Dazeley ◽  
Angel Ayala ◽  
...  
Keyword(s):  
Reinforcement Learning ◽  
Learning Process ◽  
Robotic Arm ◽  
Learning Approach ◽  
Speed Up ◽  
Open Issue ◽  
Domestic Environments ◽  
The Given ◽  
Different Sources ◽  
Interactive Feedback

Robots are extending their presence in domestic environments every day, it being more common to see them carrying out tasks in home scenarios. In the future, robots are expected to increasingly perform more complex tasks and, therefore, be able to acquire experience from different sources as quickly as possible. A plausible approach to address this issue is interactive feedback, where a trainer advises a learner on which actions should be taken from specific states to speed up the learning process. Moreover, deep reinforcement learning has been recently widely used in robotics to learn the environment and acquire new skills autonomously. However, an open issue when using deep reinforcement learning is the excessive time needed to learn a task from raw input images. In this work, we propose a deep reinforcement learning approach with interactive feedback to learn a domestic task in a Human–Robot scenario. We compare three different learning methods using a simulated robotic arm for the task of organizing different objects; the proposed methods are (i) deep reinforcement learning (DeepRL); (ii) interactive deep reinforcement learning using a previously trained artificial agent as an advisor (agent–IDeepRL); and (iii) interactive deep reinforcement learning using a human advisor (human–IDeepRL). We demonstrate that interactive approaches provide advantages for the learning process. The obtained results show that a learner agent, using either agent–IDeepRL or human–IDeepRL, completes the given task earlier and has fewer mistakes compared to the autonomous DeepRL approach.

From Discrete Vectors to Point Sets in Machining Simulations With High-Order Tool Surfaces

2013 ◽  
Author(s):  
Eyyup Aras
Keyword(s):  
Single Equation ◽  
High Order ◽  
Vector Model ◽  
Root Finding ◽  
Toroidal Surface ◽  
Tool Axis ◽  
Sharp Edges ◽  
Vertical Walls ◽  
The Given ◽  
Complicated Situation

In vector based machining simulations sampling only along one direction misses surface portions, such as sharp edges and vertical walls. This drawback can be removed when sampling along multiple directions, even without increasing the number of vectors. Therefore, given the same total number of vectors, vector hits are likely to be better distributed over the surface in a multiple-rayrep model than in a single one. But in this case, although we have a better in-process workpiece representation, we face with another problem: computational expense in the vector/envelope intersections. Computations are easy when the workpiece is represented by unidirectional vectors and when the tool axis is positioned along these vectors. On the other hand, a more complicated situation occurs when the machining simulations are performed in the multiple-reyrep based environments with tools having high-order geometries. In this case, the extensive usage of nonlinear root finding algorithms makes machining simulations impractical. One solution might be to eliminate the variable representing a vector from calculations. This leads to a union of 3D-points (i.e. polyhedral, voxel and Octree representations), at the loss of accuracy. Therefore, from a geometric viewpoint we can consider the aggregate of 3D-points as a special version of the multiple-rayrep model, in which the orthogonal vectors are discretized. In this paper, first the above mentioned drawbacks are presented for the triple-vector model based environments with arbitrarily oriented tool surfaces. Later, since each NC sequence is described by using the toolpath parameter, the above problems are reduced to a single equation with collection of toolpath parameters for the given 3D-points. Since its geometric complexity is highest among other APT-type cutter surfaces, the toroidal surface is chosen for the analysis.

scholarly journals XIX. On the conic of five-pointic contact at any point of a plane curve

1859 ◽  
Vol 149 ◽  
pp. 371-400 ◽  
Keyword(s):  
Plane Curve ◽  
Singular Points ◽  
Line Passing ◽  
The Given

The tangent is a line passing through two consecutive points of a plane curve, and we may in like manner consider the conic which passes through five consecutive points of a plane curve; and as there are certain singular points, viz. the points of inflexion, where three consecutive points of the curve lie in a line, so there are singular points where six consecutive points of the curve lie in a conic. In the particular case where the given curve is a cubic, the last-mentioned species of singular points have been considered by Plücker and Steiner, and in the same particular case, the theory of the conic of five-pointic contact has recently been established by Mr. Salmon. But the general case, where the curve is of any order whatever, has not, so far as I am aware, been hitherto considered;— the establishment of this theory is the object of the present memoir. I. Investigation of the Equation of the Conic of Five-pointic Contact . 1. I take (X, Y, Z) as current coordinates, and I represent the equation of the given curve by ϒ = (*)(X, Y, Z) m = 0. Let ( x, y, z ) be the coordinates of a given point on the curve, and let U = (*)( x, y, z ) m be what ϒ becomes when ( x, y, z ) are written in the place of (X, Y, Z); we have therefore U = 0 as a condition satisfied by the coordinates of the point in question.

scholarly journals AUTOMATIC DATA CLASSIFICATION BASED ON THE TRIANGULAR GRAPH FOR THEMATIC MAPS

2015 ◽  
Vol 41 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Zdena Dobesova
Keyword(s):  
Data Classification ◽  
Web Pages ◽  
Point Graph ◽  
Automatic Data ◽  
The Czech Republic ◽  
Thematic Map ◽  
Triangular Graph ◽  
Source Data ◽  
Automatic Tool ◽  
The Given

A triangular point graph helps in the process of data classification for a thematic map. A triangular graph can be used for a situation that is described by three variables. The total sum of variables is 100%. The proportion of three variables is plotted in an equilateral triangular graph where each side represents a coordinate for one variable. A triangular graph displays the proportions of the three variables. The position of the point indicates the type (class) of the situation in the triangular graph. The typology of the situation can be subsequently expressed in the map. We have created a “Triangular Graph” program which represents a helpful automatic tool for ArcGIS software. This new program classifies input data based on a triangular graph. It is realized by two python scripts located in a custom toolbox as two programs. The first program calculates X and Y coordinates in an equilateral triangular graph. The second program compares plotted points and suggested zones of a division produced by the first program. Finally, a new attribute is added to the source data. The user can create a new thematic map, based on that attribute in order to express the typology of the given situation. The programming language Python and essential module ArcPy have been used for solving these tasks. To test the created programs several maps were made, based on the classification often used in demography. For example, the new program helped to create a sample map of age categories in districts of the Czech Republic. The program is available to download from the Esri web pages and web pages of the Department of Geoinformatics, Palacký University Olomouc.

scholarly journals Two regularized solutions of an ill-posed problem for the elliptic equation with inhomogeneous source

Filomat ◽  
2014 ◽  
Vol 28 (10) ◽  
pp. 2091-2110 ◽  
Author(s):  
Huy Tuan ◽  
Tran Binh
Keyword(s):  
Cauchy Problem ◽  
Exact Solution ◽  
Elliptic Equation ◽  
Elliptic Equations ◽  
Numerical Examples ◽  
Source Data ◽  
Regularized Methods ◽  
Ill Posed ◽  
Convergence Estimates ◽  
The Given

In this paper, we address a Cauchy problem for elliptic equations with inhomogeneous source data. The problem is shown to be ill-posed as the solution exhibits an unstable dependence on the given data functions. Here, we shall deal with this problem by using two different regularized methods. Moreover, convergence estimates are established under some priori assumptions on the exact solution. Some numerical examples are given to illuminate the effect of our methods.

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