Coordination of Movements of Two-Handed 12-DOF Robot Manipulators at Their Joint Manipulation

2021 ◽  
pp. 11-18
Author(s):  
L.A. Karginov ◽  
E.I. Vorobyov ◽  
A.K. Kovalchuk
Keyword(s):  
Inverse Problem ◽  
Initial Data ◽  
Degrees Of Freedom ◽  
Control Flow ◽  
Flow Chart ◽  
Hierarchical Approach ◽  
Kinematic Scheme ◽  
Kinematic Constraints ◽  
Generalized Coordinates ◽  
Research Show

The study focuses on a two-handed robot with twelve degrees of freedom, six for each arm, and gives an example of calculating generalized coordinates for the two-armed robot limbs at their joint manipulation. The initial data for obtaining generalized coordinates are represented by the location of the work object, which is a cube. When solving the problem, the last arm links reach the faces of the work object with a given orientation. To obtain generalized coordinates, we used a hierarchical approach, which is based on an algorithm for solving the inverse problem of kinematics, and developed a control flow chart. The values ??of generalized robot coordinates were obtained for each location of the object of work, taking into account the kinematic constraints in the joints of the robot actuator. Findings of research show that it is possible to obtain generalized coordinates for the coordinated movement of the robot actuators with tree-like kinematic scheme.

Tracking the Motion of Hidden Segments Using Kinematic Constraints and Kalman Filtering

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
Kjartan Halvorsen ◽  
Christopher Johnston ◽  
Willem Back ◽  
Virgil Stokes ◽  
Håkan Lanshammar
Keyword(s):  
State Vector ◽  
Degrees Of Freedom ◽  
State Space Model ◽  
Nonlinear Function ◽  
The State ◽  
The Body ◽  
Joint Models ◽  
Kinematic Constraints ◽  
Generalized Coordinates ◽  
Marker Data

Motion capture for biomechanical applications involves in almost all cases sensors or markers that are applied to the skin of the body segments of interest. This paper deals with the problem of estimating the movement of connected skeletal segments from 3D position data of markers attached to the skin. The use of kinematic constraints has been shown previously to reduce the error in estimated segment movement that are due to skin and muscles moving with respect to the underlying segment. A kinematic constraint reduces the number of degrees of freedom between two articulating segments. Moreover, kinematic constraints can help reveal the movement of some segments when the 3D marker data otherwise are insufficient. Important cases include the human ankle complex and the phalangeal segments of the horse, where the movement of small segments is almost completely hidden from external observation by joint capsules and ligaments. This paper discusses the use of an extended Kalman filter for tracking a system of connected segments. The system is modeled using rigid segments connected by simplified joint models. The position and orientation of the mechanism are specified by a set of generalized coordinates corresponding to the mechanism’s degrees of motion. The generalized coordinates together with their first time derivatives can be used as the state vector of a state space model governing the kinematics of the mechanism. The data collected are marker trajectories from skin-mounted markers, and the state vector is related to the position of the markers through a nonlinear function. The Jacobian of this function is derived. The practical use of the method is demonstrated on a model of the distal part of the limb of the horse. Monte Carlo simulations of marker data for a two-segment system connected by a joint with three degrees of freedom indicate that the proposed method gives significant improvement over a method, which does not make use of the joint constraint, but the method requires that the model is a good approximation of the true mechanism. Applying the method to data on the movement of the four distal-most segments of the horse’s limb shows good between trial consistency and small differences between measured marker positions and marker positions predicted by the model.

scholarly journals Inverse Source on Conformal Conic Geometries

2020 ◽  
Author(s):  
Giovanni Leone ◽  
Fortuna Munno ◽  
Rocco Pierri
Keyword(s):  
Inverse Problem ◽  
Radiation Pattern ◽  
Degrees Of Freedom ◽  
Synthesis Problem ◽  
Source Reconstruction ◽  
Conformal Antennas ◽  
Stable Solutions

This manuscript has been accepted for publication on IEEE Transactions on Antennas and Propagation.<br><br><div>Abstract:</div><div>The paper adopts an inverse problem approach to examine the role of some 2D geometries in the source reconstruction from far zone data. It aims at evaluating the number of independent pieces of information, i.e. the number of degrees of freedom (NDF), of the source and pointing out the set of far zone fields corresponding to stable solutions of the inverse problem. Some of the results are relevant to the synthesis problem of conformal antennas, since a general comparison of different source geometries in providing radiation pattern specifications is proposed.</div>

Degrees of Freedom in a Vocal Fold Inverse Problem

2017 ◽  
pp. 475-484 ◽  
Author(s):  
Pablo Gómez ◽  
Stefan Kniesburges ◽  
Anne Schützenberger ◽  
Christopher Bohr ◽  
Michael Döllinger
Keyword(s):  
Inverse Problem ◽  
Vocal Fold ◽  
Degrees Of Freedom

An Applied Form of Kane’s Equations of Motions

2005 ◽  
Author(s):  
Hossein Nejat Pishkenari ◽  
Amir Lotfi Gaskarimahalle ◽  
Seyed Babak Ghaemi Oskouei ◽  
Ali Meghdari
Keyword(s):  
Degrees Of Freedom ◽  
Control Unit ◽  
Generalized Coordinates ◽  
Kane’S Equations ◽  
Kane's Equations ◽  
The Matrix ◽  
Angular Velocities ◽  
New Form ◽  
Derivatives Of ◽  
Equations Of Motions

In this paper we have presented a new form of Kane’s equations. This new form is expressed in the matrix form with the components of partial derivatives of linear and angular velocities relative to the generalized speeds and generalized coordinates. The number of obtained equations is equal to the number of degrees of freedom represented in a closed form. Also the equations can be rearranged to appear only one of the time derivatives of generalized speeds in each equation. This form is appropriate especially when one intends to derive equations recursively. Hence in addition to the simplicity, the amount of calculations is noticeably reduced and also can be used in a control unit.

THE CONCOMITANT-EFFECT OF ELECTRORHEOLOGICAL FLUID IN A CONTROL FLOW FIELD

2005 ◽  
Vol 19 (07n09) ◽  
pp. 1263-1269 ◽  
Author(s):  
Shi-sha ZHU ◽  
Toyohisa FUJITA ◽  
Qi-xin WANG ◽  
Kejun LIU ◽  
Gjergj DODBIBA
Keyword(s):  
Flow Field ◽  
Power Transmission ◽  
Electrorheological Fluid ◽  
Control Flow ◽  
Fluid Power ◽  
Control Technology ◽  
Capture Effect ◽  
Shearing Flow ◽  
Er Fluid ◽  
Research Show

The description of ER response in a flow field is a key issue in researching control technology of ER fluid. In this paper, an experimental work on controlling flow field in fluid power transmission has been carried out. The results of research show that the control flow field differs from the rotary shearing flow field in an experimental instrument. Besides the ER effect there is a concomitant-effect of ER response called "capture effect" in the field, which is unbeneficial to the control on fluid power transmission.

Justification of kinematic scheme small of the manipulator forestry machines

2015 ◽  
Vol 5 (3) ◽  
pp. 234-239
Author(s):  
Платонова ◽  
Marina Platonova ◽  
Драпалюк ◽  
Mikhail Drapalyuk ◽  
Платонов ◽  
...  
Keyword(s):  
Coordinate System ◽  
Reference System ◽  
Coordinate Systems ◽  
Kinematic Scheme ◽  
Inertial Coordinate System ◽  
Generalized Coordinates ◽  
Right Hand ◽  
The Absolute ◽  
Orthogonal Coordinate Systems ◽  
Base Machine

This article discusses the the selection and justification of the reference system and of the generalized coordinates for the kinematic scheme developed by of the manipulator taking into account these factors. The absolute (inertial) coordinate system associated with the center of the support member (eg turntable), joins the arm to the base machine and the subsequent coordinate system formed in accordance with the rules. On the whole, to describe the position of the investigated little detail of the manipulator in the space of generalized coordinates must be four and five right-hand orthogonal coordinate systems.

A New Hierarchical Technique for the Multiscale Modeling of Carbon Nanostructures

2005 ◽  
Author(s):  
Arash Mahdavi ◽  
Eric Mockensturm
Keyword(s):  
Finite Element ◽  
Atomic Structure ◽  
Carbon Nanostructures ◽  
Degrees Of Freedom ◽  
Finite Size ◽  
Multiscale Methods ◽  
Atomic Scale ◽  
Modeling Technique ◽  
Element Formulation ◽  
Kinematic Constraints

We present a new hierarchical modeling technique called the Consistent Atomic-scale Finite Element (CAFE´) method [1]. Unlike traditional approaches for linking the atomic structure to its equivalent continuum [2-7], this method directly connects the atomic degrees of freedom to a reduced set of finite element degrees of freedom without passing through an intermediate homogenized continuum. As a result, there is no need to introduce stress and strain measures at the atomic level. This technique partitions atoms to masters and salves and reduces the total number of degrees of freedom by establishing kinematic constraints between them [5-6]. The Tersoff-Brenner interatomic potential [8] is used to calculate the consistent tangent stiffness matrix of the structure. In this finite element formulation, all local and non-local interactions between carbon atoms are taken into account using overlapping finite elements (Figure 1b). In addition, a consistent hierarchical finite element modeling technique is developed for adaptively coarsening and refining the mesh over different parts of the model (Figure 2a, 2b). The stiffness of higher-rank elements is approximated using the stiffness of lower-rank elements and kinematic constraints. This process is consistent with the underlying atomic structure and, by refining the mesh, molecular dynamic results will be recovered. This method is valid across the scales and can be used to concurrently model atomistic and continuum phenomena so, in contrast with most other multiscale methods [4-7], there is no need to introduce artificial boundaries for coupling atomistic and continuum regions. Effect of the length scale of the nanostructure is also included in the model by building the hierarchy of elements from bottom up using a finite size atom cluster as the building block (Figures 2a, 2b). In this method by introducing two independent field variables, the so-called inner displacement is taken into account (Fig. 3b). Applicability of the method is shown with several examples of deformation of carbon nanostructures such as graphene sheet, nanotube, and nanocone, subjected to different loads and boundary conditions.

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 Radiation of a Circular Arc Source in a Limited Angle for Non-uniform Conformal Arrays

2020 ◽  
Author(s):  
Giovanni Leone ◽  
Fortuna Munno ◽  
Rocco Pierri
Keyword(s):  
Inverse Problem ◽  
Degrees Of Freedom ◽  
Angular Width ◽  
Pattern Synthesis ◽  
Circular Arc ◽  
Conformal Antennas ◽  
Radiation Properties ◽  
Near Zone ◽  
Conformal Arrays

Conformal antennas lack of general analysis methods of their radiation properties. For a circumference source, we examine the role of the angular width of the observation domain both in far and near zone in determining the set of radiated fields. By an inverse problem approach, the evaluation of the number of independent pieces of information, i.e. the number of degrees of freedom (NDF), and the analysis of the reconstructions of point-like sources allow to introduce optimal array configurations. The results are relevant to the radiation pattern synthesis problem and to array diagnostics applications.

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