679 research outputs found
Development of kinematic equations and determination of workspace of a 6 DOF end-effector with closed-kinematic chain mechanism
This report presents results from the research grant entitled Active Control of Robot Manipulators, funded by the Goddard Space Flight Center, under Grant NAG5-780, for the period July 1, 1988 to January 1, 1989. An analysis is presented of a 6 degree-of-freedom robot end-effector built to study telerobotic assembly of NASA hardware in space. Since the end-effector is required to perform high precision motion in a limited workspace, closed-kinematic mechanisms are chosen for its design. A closed-form solution is obtained for the inverse kinematic problem and an iterative procedure employing Newton-Raphson method is proposed to solve the forward kinematic problem. A study of the end-effector workspace results in a general procedure for the workspace determination based on link constraints. Computer simulation results are presented
Conceptual designs of multi-degree of freedom compliant parallel manipulators composed of wire-beam based compliant mechanisms
This paper proposes conceptual designs of multi-degree(s) of freedom (DOF) compliant parallel manipulators (CPMs) including 3-DOF translational CPMs and 6-DOF CPMs using a building block based pseudo-rigid-body-model (PRBM) approach. The proposed multi-DOF CPMs are composed of wire-beam based compliant mechanisms (WBBCMs) as distributed-compliance compliant building blocks (CBBs). Firstly, a comprehensive literature review for the design approaches of compliant mechanisms is conducted, and a building block based PRBM is then presented, which replaces the traditional kinematic sub-chain with an appropriate multi-DOF CBB. In order to obtain the decoupled 3-DOF translational CPMs (XYZ CPMs), two classes of kinematically decoupled 3-PPPR (P: prismatic joint, R: revolute joint) translational parallel mechanisms (TPMs) and 3-PPPRR TPMs are identified based on the type synthesis of rigid-body parallel mechanisms, and WBBCMs as the associated CBBs are further designed. Via replacing the traditional actuated P joint and the traditional passive PPR/PPRR sub-chain in each leg of the 3-DOF TPM with the counterpart CBBs (i.e. WBBCMs), a number of decoupled XYZ CPMs are obtained by appropriate arrangements. In order to obtain the decoupled 6-DOF CPMs, an orthogonally-arranged decoupled 6-PSS (S: spherical joint) parallel mechanism is first identified, and then two example 6-DOF CPMs are proposed by the building block based PRBM method. It is shown that, among these designs, two types of monolithic XYZ CPM designs with extended life have been presented
Dynamics of the Orthoglide parallel robot
Recursive matrix relations for kinematics and dynamics of the Orthoglide
parallel robot having three concurrent prismatic actuators are established in
this paper. These are arranged according to the Cartesian coordinate system
with fixed orientation, which means that the actuating directions are normal to
each other. Three identical legs connecting to the moving platform are located
on three planes being perpendicular to each other too. Knowing the position and
the translation motion of the platform, we develop the inverse kinematics
problem and determine the position, velocity and acceleration of each element
of the robot. Further, the principle of virtual work is used in the inverse
dynamic problem. Some matrix equations offer iterative expressions and graphs
for the input forces and the powers of the three actuators
WORKSPACE ANALYSIS AND OPTIMIZATION OF THE PARALLEL ROBOTS BASED ON COMPUTER-AIDED DESIGN APPROACH
This paper provides workspace determination and analysis based on the graphical technique of both spatial and planar parallel manipulators. The computation and analysis of workspaces will be carried out using the parameterization and three-dimensional representation of the workspace. This technique is implemented in CAD (Computer Aided Design) Software CATIA workbenches. In order to determine the workspace of the proposed manipulators, the reachable region by each kinematic chain is created as a volume/area; afterwards, the full reachable workspace is obtained by the application of a Boolean intersection function on the previously generated volumes/areas. Finally, the relations between the total workspace and the design parameters are simulated, and the Product Engineering Optimizer workbench is used to optimize the design variables in order to obtain a maximized workspace volume. Simulated annealing (SA) and Conjugate Gradient (CG) are considered in this study as optimization tools
Robotization of hand woven carpet technology process
Thesis (Master)--Izmir Institute of Technology, Mechanical Engineering, Izmir, 2008Includes bibliographical references (leaves: 85-91)Text in English; Abstract: Turkish and Englishxi, 96 leavesThis thesis covers a study on the structural design of new overconstrained mechanisms and manipulators and their application to the robotization of hand woven carpet technology process.Moreover, recurrent vector equations are investigated for the synthesis of linkages, and used for the design of new mechanisms with linear-angular conditions in the subspace with general constraint one. These conditions are generalized for defining the structural groups of subspace ..5 and these structural groups are used both for the creation of new parallel manipulators and new serial-parallel platform manipulators.After investigating hand woven carpets, the knowledge gained during the structural design of mechanisms is applied to the robotization of hand woven carpet technology process. Finally, design of carpet weaving robot is introduced
CAD-based approach for identification of elasto-static parameters of robotic manipulators
The paper presents an approach for the identification of elasto-static
parameters of a robotic manipulator using the virtual experiments in a CAD
environment. It is based on the numerical processing of the data extracted from
the finite element analysis results, which are obtained for isolated
manipulator links. This approach allows to obtain the desired stiffness
matrices taking into account the complex shape of the links, couplings between
rotational/translational deflections and particularities of the joints
connecting adjacent links. These matrices are integral parts of the manipulator
lumped stiffness model that are widely used in robotics due to its high
computational efficiency. To improve the identification accuracy,
recommendations for optimal settings of the virtual experiments are given, as
well as relevant statistical processing techniques are proposed. Efficiency of
the developed approach is confirmed by a simulation study that shows that the
accuracy in evaluating the stiffness matrix elements is about 0.1%.Comment: arXiv admin note: substantial text overlap with arXiv:0909.146
Design and analysis of a parallel mechanism for kinematically redundant hybrid planar laser cutting machine
Conventional planar laser cutting machines cannot achieve high accelerations, because the required precision values cannot be achieved due to the high inertial loads. Machines configured as kinematically redundant mechanisms are able to reach 5-6 g acceleration levels since they include a parallel mechanism with a smaller workspace which is exposed to smaller inertial loads. The study presented in this paper focuses on the design of a parallel planar mechanism to be integrated to the main axes of conventional planar laser cutting machines to achieve higher accelerations of the laser head up to 6 g. Parallel mechanism’s conceptual design and dynamic balancing studies are provided along with the joint clearance effect on precision due to having more joint structures.Republic of Turkey Ministry of Science, Industry and Technology & Coşkunöz Metal Form (Project code: 01668.STZ.2012-2
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