802 research outputs found
Co ordinate Transformations and Programming For Small Revolute Coordinate Robots
Inorder for a robot and effector to make contact at any orientation with a workpiece in general 3-D space, the robot must be provided with six degrees of freedom
An investigation of singularities in robot kinematic chains aiming at building robot calibration models for off-line programming
Robot Calibration is a term applied to the procedures used in determining actual values that describe the geometric dimensions and mechanical characteristics of a robot or multibody structure. A robot calibration system must consist of appropriate robot modeling techniques, accurate measurement equipment, and reliable model parameter determination methods. For practical improvement of a robot's absolute accuracy, error compensation methods are required that use calibration results. Important to robot calibration methods is an accurate kinematic model that has identifiable parameters. This parameterized kinematic model must be complete, continuous and minimal. This work concerns to the implementation of techniques to optimize kinematic models for robot calibration through numerical optimization of the mathematical model. The optimized model is then used to compensate the model errors in an off-line programming system, enhancing significantly the robot kinematic model accuracy. The optimized model can be constructed in an easy and straight operation, through automatic assignment of joint coordinate systems and geometric parameter to the robot links. Assignment of coordinate systems by this technique avoids model singularities that usually spoil robot calibration results
Delta robot motion control
Abstract. The aim of this thesis is to generate a functional motion control to a delta robot. The motion control is based on solving the inverse kinematics problem of the delta robot. This solution is then used to form the control logic of the robot. In addition, this thesis also introduces forward kinematics solution models and, the most common industrial robots and their features. Applications of industrial robots, as well as the industries that utilize them the most are also examined.
This thesis introduces a self-made delta robot and its motion control design. The functionality of motion control is studied by measuring the positioning accuracy as well as the repeatability of the self-made delta robot in the xy-plane. Accuracy measurements are performed using a separate measuring device. A small-scale comparison between the positioning accuracy of a self-made and a commercial delta robot is implemented to find out how closely can the performance of a commercial delta robot be reproduced with a self-made delta robot.
The results of this thesis indicate that the inverse kinematics model of the delta robot as well as the motion control actually work. The results demonstrate that the performance of the self-made delta robot is at a good level and that further development is worthwhile. There was not enough measurement data to perform a proper comparison between the self-made and the commercial delta robot. However, despite the narrow sampling, it is assumed that the positioning accuracy of the self-made delta robot is not yet at the same level as that of the commercial product.
The accuracy of the self-made delta robot presented in this thesis can be improved by developing the feeding of the robot’s drive commands. The materials used in the construction of the robot as well as the quality of the joints also affect the accuracy.
The inverse kinematics model of the delta robot presented in this thesis can be easily scaled to different sized delta robots depending on the application. Motion control can be utilized in the control of delta robots implemented with a similar mechanical structure.Delta-robotin liikkeenohjaus. Tiivistelmä. Tämän työn tarkoituksena on suunnitella delta-robotille toimiva liikkeenohjaus. Liikkeenohjauksen rakentaminen perustuu delta-robotin käänteiskinematiikan ratkaisemiseen. Käänteiskinematiikan ratkaisua hyödynnetään ohjauslogiikan toteutuksessa. Työssä tutustutaan myös suorankinematiikan ratkaisumalleihin, sekä esitellään yleisimpiä teollisuusrobotteja ja niiden ominaisuuksia. Työssä tarkastellaan myös teollisuusrobottien käyttökohteita, sekä niitä eniten hyödyntävät teollisuudenalat.
Työssä tutustutaan omavalmisteiseen delta-robottiin ja sen liikkeenohjauksen suunnitteluun. Liikkeenohjauksen toimivuutta tutkitaan mittaamalla omavalmisteisen delta-robotin paikoitustarkkuus, sekä toistotarkkuus xy-tasossa. Tarkkuusmittaukset toteutetaan käyttämällä erillistä mittalaitetta. Työssä pyritään myös selvittämään kuinka lähelle kaupallisen delta-robotin suorituskykyä voidaan päästä omavalmisteisella delta-robotilla. Työssä toteutetaan pienimuotoinen vertailu omavalmisteisen ja kaupallisen delta-robotin paikoitustarkkuuden välillä.
Työn tulokset osoittavat, että delta-robotin käänteiskinematiikan malli, sekä liikkeenohjaus toimivat. Tuloksista selviää, että omavalmisteisen delta-robotin suorituskyky on hyvällä tasolla ja sen kehittämistä kannattaa jatkaa. Omavalmisteisen ja kaupallisen delta-robotin kunnolliseen vertailuun ei saatu riittävästi dataa. Suppeasta otannasta huolimatta on kuitenkin oletettavaa, että omavalmisteisen delta-robotin paikoitustarkkuus ei vielä yllä samalle tasolle kaupallisen tuotteen kanssa.
Työssä esitellyn omavalmisteisen delta-robotin tarkkuutta saadaan parannettua kehittämällä robotin ajokomentojen syöttämistä. Myös robotin rakenteessa käytetyt materiaalit, sekä nivelten laadukkuus vaikuttavat tarkkuuteen.
Työssä esitetty delta-robotin käänteiskinematiikan malli on helposti skaalattavissa myös erikokoisiin delta-robotteihin käyttökohteesta riippuen. Liikkeenohjausta voidaan hyödyntää vastaavalla mekaanisella rakenteella toteutettujen delta-robottien ohjauksessa
Graphical modelling of modular machines
This research is aimed at advancing machine design through specifying and implementing
(in "proof of concept" form) a set of tools which graphically model modular machines.
The tools allow mechanical building elements (or machine modules) to be selected and
configured together in a highly flexible manner so that operation of the chosen configuration
can be simulated and performance properties evaluated. Implementation of the tools
has involved an extension in capability of a proprietary robot simulation system. This research has resulted in a general approach to graphically modelling manufacturing machines
built from modular elements.
A focus of study has been on a decomposition of machine functionality leading to the establishment
of a library of modular machine primitives. This provides a useful source of
commonly required machine building elements for use by machine designers. Study has
also focussed on the generation of machine configuration tools which facilitate the construction
of a simulation model and ultimately the physical machine itself. Simulation aspects
of machine control are also considered which depict methods of manipulating a
machine model in the simulation phase. In addition methods of achieving machine programming
have been considered which specify the machine and its operational tasks.
Means of adopting common information data structures are also considered which can facilitate
interfacing with other systems, including the physical machine system constructed
as an issue of the simulation phase. Each of these study areas is addressed in its own context,
but collectively they provide a means of creating a complete modular machine design
environment which can provide significant assistance to machine designers.
Part of the methodology employed in the study is based on the use of the discrete event
simulation technique. To easily and effectively describe a modular machine and its activity
in a simulation model, a hierarchical ring and tree data structure has been designed and
implemented. The modularity and reconfigurability are accommodated by the data structure,
and homogeneous transformations are adopted to determine the spatial location and
orientation of each of the machine elements.
A three-level machine task programming approach is used to describe the machine's activities.
A common data format method is used to interface the machine design environment
with the physical machine and other building blocks of manufacturing systems (such as
CAD systems) where systems integration approaches can lead to enhanced product realisation.
The study concludes that a modular machine design environment can be created by employing
the graphical simulation approach together with a set of comprehensive configuration.
tools. A generic framework has been derived which outlines the way in which
machine design environments can be constructed and suggestions are made as to how the
proof of concept design environment implemented in this study can be advanced
Generalized approach to the modelling of modular machines
This paper describes a method of graphically simulating modular machines within a computer aided design environment. This forms part of a much larger Science and Engineering Research Council (SERC) funded programme aimed at advancing modern practices when designing and building manufacturing machines. A generalized approach to the synthesis of the generic features of various kinematic motion pairs is presented and prismatic and revolute motion primitives generalized in their functional and geometric aspects. A hierarchical ring and tree data structure has been designed and implemented to comprehensively represent these motion pairs and to simulate their performance. More complex modular manufacturing machines can be represented using information from a library of up to three degree of freedom motion modules. Seven two degree of freedom motion primitives and twelve three degree of freedom motion primitives with articulation configurations have been analyzed and included in the motion primitive library. The configuration of modular machines comprised of physically separate but logically connected distributed motion primitives are described. Examples of a two-finger industrial robot gripper and a three-finger industrial robot hand are used to demonstrate the general principles
Advancement in robot programming with specific reference to graphical methods
This research study is concerned with the derivation of advanced robot
programming methods. The methods include the use of proprietary
simulation modelling and design software tools for the off-line
programming of industrial robots. The study has involved the generation
of integration software to facilitate the co-operative operation of these
software tools.
The three major researcli'themes7of "ease of usage", calibration and the
integration of product design data have been followed to advance robot
programming. The "ease of usage" is concerned with enhancements in the
man-machine interface for robo t simulation systems in terms of computer
assisted solid modelling and computer assisted task generation.
Robot simulation models represent an idealised situation, and any off-line
robot programs generated from'them may contain'discrepancies which could
seriously effect thq programs' performance; Calibration techniques have
therefore been investigated as 'a method of overcoming discrepancies
between the simulation model and the real world.
At the present time, most computer aided design systems operate as
isolated islands of computer technology, whereas their product databases
should be used to support decision making processes and ultimately
facilitate the generation of machine programs. Thus the integration of
product design data has been studied as an important step towards truly
computer integrated manufacturing.
The functionality of the three areas of study have been generalised and
form the basis for recommended enhancements to future robot programming
systems
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