| 1. |
- Björkman, Mattias, et al.
(författare)
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A New Concept for Motion Control of Industrial Robots
- 2008
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Ingår i: Proceedings of the 17th IFAC World Congress. - Linköping : Linköping University Electronic Press. - 9783902661005
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Konferensbidrag (refereegranskat)abstract
- This paper gives a short summary of an industrial development work on model-based motion control. This development has resultet in high robot motion performance simultaneously with an efficient use of the installed drive system of the robot.
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| 2. |
- Blomdell, Anders, et al.
(författare)
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Extending an Industrial Robot Controller-Implementation and Applications of a Fast Open Sensor Interface
- 2005
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Ingår i: IEEE Robotics & Automation Magazine. - 1070-9932. ; 12:3, s. 85-94
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Tidskriftsartikel (refereegranskat)abstract
- Many promising robotics research results were obtained during the late 1970s and early 1980s. Some examples include Cartesian force control and advanced motion planning. Now, 20 years and many research projects later, many technologies still have not reached industrial usage. An important question to consider is how this situation can be improved for future deployment of necessary technologies. Today, modern robot control systems used in industry provide highly optimized motion control that works well in a variety of standard applications. To this end, computationally intensive, model-based robot motion control techniques have become standard during the last decade. While the principles employed have been known for many years, deployment in products required affordable computing power, efficientengineering tools, customer needs for productivity/performance, and improved end-user competence in the utilization of performance features. However, applications that are considered nonstandard today motivate a variety of research efforts and system development to package results in a usable form. Actually, robots are not useful for many manufacturing tasks today, in particular those found in small and medium enterprises (SMEs). Reasonsinclude complex configuration, nonintuitive (for the shop floor) programming, and difficulties instructing robots to deal with variations in their environment. The latter challenge includes both task definitions and definition of motion control utilizing external sensors. The key word here is flexibility, and flexible motion control is particularly difficult since the user or system integrator needs to influence the core real-time software functions that are critical for the performance and safe operation of the system. We must find techniques that permit real-time motion controllers to be extended for new, demanding application areas.
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| 3. |
- Carvalho Bittencourt, André, et al.
(författare)
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An Extended Friction Model to capture Load and Temperature effects in Robot Joints
- 2010
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Ingår i: Proceedings of the 2010 IEEE/RSJ International Conference on Intelligent Robots and Systems. - Linköping : Linköping University Electronic Press. - 9781424466740 ; , s. 6161-6167
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Konferensbidrag (refereegranskat)abstract
- Friction is the result of complex interactions between contacting surfaces in a nanoscale perspective. Depending on the application, the different models available are more or less suitable. Available static friction models are typically considered to be dependent only on relative speed of interacting surfaces. However, it is known that friction can be affected by other factors than speed. In this paper, static friction in robot joints is studied with respect to changes in joint angle, load torque and temperature. The effects of these variables are analyzed by means of experiments on a standard industrial robot. Justified by their significance, load torque and temperature are included in an extended static friction model. The proposed model is validated in a wide operating range, reducing the average error a factor of 6 when compared to a standard static friction model.
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| 4. |
- Carvalho Bittencourt, André, et al.
(författare)
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Modeling and Identification of Wear in a Robot Joint under Temperature Uncertainties
- 2010
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This paper considers the problem of wear estimation in a standard industrial robot joint. The effects of wear to the static friction of a robot joint are analyzed from experiments. An extended static friction model is proposed that explains changes related to joint speed, load, temperature and wear. Based on this model and static friction observations, a model-based wear estimator is proposed. The performance of the estimator under temperature uncertainties is found both by means of simulations and experiments in an industrial robot. Special attention is given to the analyses of the best speed region for wear estimation. As it is shown, the method can distinguish the effects of wear even under large temperature variations, opening up for the use of robust joint diagnosis for industrial robots.
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| 5. |
- Carvalho Bittencourt, André, et al.
(författare)
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Modeling and Identification of Wear in a Robot Joint under Temperature Uncertainties
- 2011
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- This paper considers the problem of wear estimation in a standard industrial robot joint. The effects of wear to the static friction of a robot joint are analyzed from experiments. An extended static friction model is proposed that explains changes related to joint speed, load, temperature and wear. Based on this model and static friction observations, a model-based wear estimator is proposed. The performance of the estimator under temperature uncertainties is found both by means of simulations and experiments in an industrial robot. Special attention is given to the analyses of the best speed region for wear estimation. As it is shown, the method can distinguish the effects of wear even under large temperature variations, opening up for the use of robust joint diagnosis for industrial robots.
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| 6. |
- Crothers, Phil, et al.
(författare)
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Characterization of the Tau parallel kinematic machine for aerospace application
- 2009
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Ingår i: SAE 2009 AeroTech Congress & Exhibition Technical Papers.
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Konferensbidrag (refereegranskat)abstract
- A consortium of interested parties has conducted an experimental characterization of two Tau parallel kinematic machines which were built as a part of the EU-funded project, SMErobot1. Characteristics such as machine stiffness, work envelope, repeatability and accuracy were considered. This paper will present a brief history of the Tau parallel machine, the results of this testing and some comment on prospective application to the aerospace industry.
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| 7. |
- Dressler, Isolde, et al.
(författare)
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A Kinematic Error Model for a Parallel Gantry-Tau Manipulator
- 2010
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Ingår i: ; , s. 3709-3714
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Konferensbidrag (refereegranskat)abstract
- Parallel robots are generally said to be more accurate but to have a smaller workspace compared to serial robots. With the Gantry-Tau robot, a parallel robot with a large, reconfigurable workspace was presented. This article tries to identify the maximum achievable end-effector positioning accuracy of the Gantry-Tau robot. To this end, a couple of new kinematic error models are presented and evaluated. The sources of the remaining positioning errors (0.09 mm) are discussed.
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| 8. |
- Gunnar, Johan, et al.
(författare)
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Nonlinear Grey-box Identification of Linear Actuators Containing Hysteresis
- 2006
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Ingår i: Proceedings of the 2006 IEEE International Conference on Robotics and Automation. - Linköping : Linköping University Electronic Press. - 0780395050 ; , s. 1818-1823
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Konferensbidrag (refereegranskat)abstract
- A new identification procedure for a linear actuator used in parallel kinematic manipulators has been developed. The actuator dynamics contain both hysteresis and backlash resulting in a highly nonlinear system. The results in this paper show that not only can a nonlinear model of the system be successfully identified from measurement data, but the model is also compact enough to be an ideal candidate for inclusion in a high-performance robot control system.
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| 9. |
- Haage, Mathias, et al.
(författare)
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Reconfigurable Parallel Kinematic Manipulator for Flexible Manufacturing
- 2009
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Ingår i: 13th IFAC Symposium on Information Control Problems in Manufacturing. - 9783902661432 ; 42:4, s. 145-150
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Konferensbidrag (refereegranskat)abstract
- Flexible manufacturing puts high demands on industrial automation in terms of affordable and competitive solutions and is of key importance for short-lot production typically found in small and medium sized enterprises, situations where today manual labour is extensively used despite environmental issues and harsh working conditions. Key factors in the successful introduction of new robot automation concepts are that they provide both the desired performance and quality (technical capability), but also that they enable fast deployment and extend available task repertoire. The Gantry-Tau manipulator is a new robot concept which in contrast to other high-performance parallel kinematic manipulators (PKM), has a large, open working range. Its high stiffness makes it ideal for a wide range of tasks such as grinding, deburring, and cutting. An additional aspect of such a PKM is the modularity, which in this work has been studied in terms of possibilities for assembly and mechanical reconfiguration at the end-user site, integration of such a kinematically different robot with a standard industrial controller, and new needs for methods/tools to support simple (re)configuration. A range of software tools and methods were found to be useful and necessary for efficient engineering and integration of the concept in typical SME manufacturing scenarios. For experimental evaluation, two full-scale prototype robots were designed and built, the kinematic software was developed and integrated into a couple of different robot control systems, robot CAD software was adapted to the configuration needs, and both simulations and physical experiments were carried out. Our findings make us believe that enhanced software tools should be integrated on a higher symbolic (or meta-) level to better support transformation of data and code generation, but also that the Gantry-Tau type of robot (with adequate software support) will bring a new dimension of flexibility into SME manufacturing.
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| 10. |
- Holm, Ulf, et al.
(författare)
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Measurement system for magneto-optic sensor materials
- 1984
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Ingår i: Journal of Physics E: Scientific Instruments. - : The Institute of Physics. - 0022-3735. ; 17:10, s. 885-889
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Tidskriftsartikel (refereegranskat)abstract
- A system for the measurements of magneto-optic properties of IR-transparent materials is described. The system is designed for the characterisation of fibre optic magnetic field sensor materials. Measurement results on YIG-crystals are prresented. The accuracy of Faraday rotation and light transmission measurements are ±2 mrad and ±2% respectively. Important features for the sensor characterisation are light beam scanning, temperature control and flexible magnetic field generation. A desktop computer is used for system control and data acquisition. The system is expected to be of great importance for future sensor developments.
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| 11. |
- Holm, Ulf, et al.
(författare)
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YIG-SENSOR DESIGN FOR FIBER OPTICAL MAGNETIC-FIELD MEASUREMENTS
- 1984
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Ingår i: PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS, volume 0514. ; , s. 333-336
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Konferensbidrag (refereegranskat)abstract
- Aiming at the design of a magnetic field sensor utilizing the Faraday effect, we give in this paper a description of measurements of magneto-optical properties of YIG. We also give sensor design rules based upon these measurements.
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| 12. |
- Johannesson, Lars, 1979, et al.
(författare)
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Gantry Tau – A New Parallel Kinematic Robot
- 2004
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Ingår i: Proceedings of the 4th Chemnitz Parallel Kinematics Seminar, (Ed.: Reimund Neugebauer), April 20-21, 2004, Verlag Wissenschaftliche Scripten. - 3937524053 ; , s. 731-734
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Konferensbidrag (refereegranskat)abstract
- A new parallel structure, the Gantry Tau, is introduced. The structure provides 3 degrees of freedom translational motion with a large workspace. The structures nominal kinematics is identical to the Linear Delta robot. In order to yield a design of the Gantry Tau with a large workspace volume and good kinematic properties, multi-criteria optimization is used. Different geometrical layouts are examined and the Pareto optimality between the objective functions is found.
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| 13. |
- Johannesson, Lars, 1979, et al.
(författare)
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Gantry-Tau – A New Three Degrees of Freedom Parallel Kinematic Robot
- 2003
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In the last decades, an increasing attention has been paid to the study of different parallel structure mechanisms and their applications, mainly triggered by Stewart that presented an aircraft simulator system. Parallel structure features provide big advantages in potential applications. For example, parallel robots may give higher speed and acceleration, higher static and dynamic accuracy and higher stiffness than what is possible with the industrial robots used today. A typical limitation with many of the paral-lel structures is that their workspace is small com-pared to the serial structures. This paper presents a new parallel structure, the Gantry-Tau, which pro-vides 3 degrees of freedom (DOF) translational mo-tion with a large workspace. The structure of the ro-bot is patented by ABB. The Gantry-Tau robot is a six link parallel kinematic structure with the links configured according to 3-2-1. The 3-2-1 notation refers to how many links form each resulting kine-matic cluster of the robot. Orientational DOF of the robot could be provided by a decoupled system. For a conventional 3 DOF serial gantry ro-bot two of the actuators contribute to the moving mass. The Gantry-Tau can be constructed with ex-ceptionally low moving mass since the actuators are stationary and the structure has inherently high stiff-ness. The structure is thus ideal for many applications with demands on high accelerations, for instance for the pick and place operations. The nominal inverse and direct kinematics of the structure are developed and optimization is used to find a construction of Gantry-Tau with maximum workspace volume.
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| 14. |
- Johansson, Rolf, et al.
(författare)
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Sensor Integration in Task-level Programming and Industrial Robotic Task Execution Control
- 2004
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Ingår i: Industrial Robot. - : Emerald. - 0143-991X. ; 31:3, s. 284-296
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Tidskriftsartikel (refereegranskat)abstract
- Presents an approach to improved performance and flexibility in industrial robotics by means of sensor integration and feedback control in task-level programming and task execution. Also presents feasibility studies in support of the ideas. Discusses some solutions to the problem using six degrees of freedom force control together with the ABB S4CPlus system as an illustrative example. Consider various problems in the design of an open sensor interface for industrial robotics and discusses possible solutions. Finally, presents experimental results from industrial force controlled grinding.
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| 15. |
- Kihlman, Henrik, et al.
(författare)
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On the Use of Force Feedback for Cost Efficient Robotic Drilling
- 2007
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Ingår i: SAE Technical Paper Series. - Los Angeles, CA, US : Society of Automotive Engineers. - 0148-7191.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Drilling is one of the most costly and labour-intensive operations in aircraft assembly. Rather than automating with expensive fixtures and precise machinery, our approach is to make use of standard low-cost robot equipment in combination with sensor feedback. The focus is to eliminate the sliding movement of the end-effector during the clamp-up, called the skating effect, and to keep the end-effector orthogonal to the surface, thus avoiding holes that are not perpendicular. To that end, force feedback is used for building up pressure to clamp up an end-effector to the work-piece surface prior to drilling. The system, including the planning of force parameters for each hole to be drilled, was programmed in DELMIA. The drilling was accomplished with the aid of an extension to the ABB Rapid language called ExtRapid, which is an XML-like code that is interpreted by the force feedback controller downstream in the process. Although experimental results are from drilling, the conceptual idea is believed to be useful in many other applications requiring external sensor feedback control of industrial robots.
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| 16. |
- Moberg, Stig, 1962-, et al.
(författare)
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Modeling and Parameter Estimation of Robot Manipulators Using Extended Flexible Joint Models
- 2014
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Ingår i: Journal of Dynamic Systems Measurement, and Control. - : ASME International. - 0022-0434 .- 1528-9028. ; 136:3, s. 031005-
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Tidskriftsartikel (refereegranskat)abstract
- This paper considers the problem of dynamic modeling and identification of robot manipulators with respect to their elasticities. The so-called flexible joint model, modeling only the torsional gearbox elasticity, is shown to be insufficient for modeling a modern industrial manipulator accurately. Another lumped parameter model, called the extended flexible joint model, is therefore used to improve the model accuracy. In this model, nonactuated joints are added to model the elasticity of the links and bearings. The unknown elasticity parameters are estimated using a frequency-domain gray-box identification method. The conclusion is that the obtained model describes the movements of the motors and the tool mounted on the robot with significantly higher accuracy than the flexible joint model. Similar elasticity model parameters are obtained when using two different output variables for the identification, the motor position and the tool acceleration.
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| 17. |
- Nilsson, Klas, et al.
(författare)
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Productive Robots and the SMErobot Project
- 2005
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Ingår i: Book of Abstracts of Third Swedish Workshop on Autonomous Robotics.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The need for keeping manufacturing and workplacesin Europe calls for new ideas and concepts for productiverobots with focus on their usefulness for Small andMedium sized Enterprises (SMEs). The activitiesfrom the Robotics Research at LTH, [3], [4], [2], andin particular those related to the SMErobot project[1] comprise efforts in this direction. The SMErobotproject is a recently started four-year-project of the6th Framework Programme of the EC "to create anew family of SME-suitable robots and to exploit itspotentials for competitive SME manufacturing". Tothis purpose the goal is not to create fully autonomousrobots for all possible tasks, but rather to createsemi-autonomous robots and to allow for human-robotinteraction in a safe way.
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| 18. |
- Pettersson, Marcus, 1977-
(författare)
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Design Optimization in Industrial Robotics : Methods and Algorithms for Drive Train Design
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Robot manufacturers, like many other manufacturers, are experiencing increasing competition in a global market where one way to confront the challenge is by making the development process more efficient. One way to speed up the time to market for new products is to take advantage of design optimization based on simulation models. By optimizing performance with the help of dynamic simulation, an immense amount of both time and money may be saved.In this thesis, design optimization strategies for industrial robot design are studied. Often, the trade-offs between performance, cost and quality are essential for design decisions. These tradeoffs can be investigated with the help of simulation models. Generating the trade-offs can be both cumbersome and time-consuming, but the process may be partly automated with the help of optimization algorithms. How the optimization problem needs to be formulated to generate the trade-off is discussed in this thesis.Robot design problems usually consist of a mixture of deciding continuous parameters as well as selecting components from catalogs and databases. Hence, there is a need for optimization algorithms which can handle variables of both a discrete and a continuous nature. A new method has been developed to address this problem. The method has also been improved by adding adaptive characteristics for further efficient design optimization.The ideas in this thesis have been applied to both simulation models of conceptual degrees of elaboration as well as simulation models of complete robot systems. An optimization procedure which shows how optimization can be used in the early phases of a development process is developed. The objective of the optimization is to determine optimal gearboxes and arm lengths from an acceleration capability perspective. An optimization based design method for robot drive trains is also presented. For further efficient use of already installed robots the concept of application adapted performance optimization is introduced. This means that the robot control is optimized with respect to thermal and fatigue load for the specific program that the robot performs. The motion program itself, i.e. the path planning, can be optimized at the same time in order to get the most out of the robot.
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| 19. |
- Reddy Vemula, Bhanoday, et al.
(författare)
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Structural synthesis of 3DOF Articulated Manipulators based on Kinematic Evaluation
- 2013
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Ingår i: 16th International Conference on Advanced Robotics ICAR 2013. ; , s. Article number 6766460-
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Konferensbidrag (refereegranskat)abstract
- In this study, serial and parallelogram linkage structures are evaluated and compared, on the basis of kinematic performance measures such as workspace and manipulability. Tradeoff relationships between workspace manipulability are established for both the structures, using the configuration of the arm lengths as a design variable. The structures are also analyzed on the basis of their manipulation ability in specific regions of their workspace, providing additional design criteria during the selection of the kinematic structure in the synthesis of industrial articulated robots.
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| 20. |
- Robertsson, Anders, et al.
(författare)
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Implementation of Industrial Robot Force Control Case Study: High Power Stub Grinding and Deburring
- 2006
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Ingår i: 2006 IEEE/RSJ International Conference on Intelligent Robots and Systems (IEEE Cat. No. 06CH37780D). - 1424402581 ; , s. 2743-2748
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Konferensbidrag (refereegranskat)abstract
- In this paper, the results from a joint industry-academia project in industrial robotic force control are presented. The extension and implementation of an external sensor system for an industrial robot system, which can be used for high-bandwidth force control, are described. Results from two industrial applications using the system are presented, a stub grinding application using a new compliant grinding end-effector integrated with the robot control system, and a deburring application with a stiff tool requiring high-bandwidth force control in six degrees of freedom. Using the system an easily reconfigurable control structure was achieved, which was able to control contact forces with a sampling bandwidth of an order of magnitude higher than for conventional robot controllers
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