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| 2. |
- Björkenstam, Staffan C, 1981, et al.
(författare)
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Efficient sequencing of industrial robots through optimal control
- 2014
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Ingår i: 5th CIRP Conference on Assembly Technologies and Systems, November 13-14, 2014, Dresden, Germany. - : Elsevier BV. - 2212-8271. ; 23:C, s. 194-199
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Konferensbidrag (refereegranskat)abstract
- In a production plant for complex assembled products there could be up to several hundred robots used for handling and joining operations. Thus, improvements in robot motion can have a huge impact on equipment utilization and energy consumption. By combining recent algorithms for collision free numerical optimal control and for optimal sequencing, we are able to cut down on energy consumption without sacrificing cycle time. The algorithm has been successfully applied to several industrial cases demonstrating that the proposed method can be used effectively in practical applications to find fast and energy efficient solutions.
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| 3. |
- Hermansson, Tomas, 1979, et al.
(författare)
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Identification of Material Parameters of Complex Cables from Scanned 3D Shapes
- 2016
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Ingår i: Procedia CIRP: 14th CIRP CAT 2016 - CIRP Conference on Computer Aided Tolerancing. - : Elsevier BV. - 2212-8271. ; 43, s. 280-285
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Konferensbidrag (refereegranskat)abstract
- Simulation of flexible components is becoming an integral part of virtual product design. However, for a simulation model to predict physically correct deformations, it is crucial that the material parameters are authentic. Conventional methods to acquire these parameters involve extensive force-displacement measurements, which may be unpractical or too expensive to perform. We propose an alternative method to identify the material parameters of a flexible one-dimensional component, such as a cable or a hose, from a scanned set of deformed reference shapes. The method finds the model parameters that give the best geometric fit between the model and the reference shapes.
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| 4. |
- Jareteg, Cornelia, 1986, et al.
(författare)
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Geometry Assurance Integrating Process Variation with Simulation of Spring-in for Composite Parts and Assemblies
- 2014
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Ingår i: Proc. of ASME 2014 International Mechanical Engineering Congress & Exposition. - 9780791846438 ; 2A
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Konferensbidrag (refereegranskat)abstract
- Geometrical variation and deviation in all manufacturing processes affect quality of the final product. Therefore geometry assurance is an important tool in the design phase of a new product. In the automotive and aviation industries where the use of composite parts is increasing drastically, new tools within variation simulations are needed. Composite parts tend to deviate more from nominal specification compared to metal parts. Methods to simulate the manufacturing process of composites have been developed before. In this paper we present how to combine the process variation simulation of composites with traditional variation simulations. The proposed method is demonstrated on a real complex subassembly, representing part of an aircraft wing-box. Since traditional variation simulation methods are not able to capture the spring-in and the special deviation behavior of composites,the proposed method adds a new feature and reliability to the geometry assurance process of composite assemblies.
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| 5. |
- Jareteg, Cornelia, 1986, et al.
(författare)
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Variation simulation for composite parts and assemblies including variation in fiber orientation and thickness
- 2014
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Ingår i: Procedia CIRP CATS 2014. 5th CATS 2014 - CIRP Conference on Assembly Technologies and Systems. - : Elsevier BV. - 2212-8271. ; 23, s. 235-240
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Konferensbidrag (refereegranskat)abstract
- All manufacturing processes are afflicted by geometrical variation, which can lead to defect products. A simulation tool for geometry assurance analysis is therefore important in the design process. The use of composites has recently increased drastically, but there is still a lack of understanding about the effects of variation in such parts. A method for predicting variation in subassemblies, including variation in fiber orientation and ply thickness for composites is presented. The approach is demonstrated on an industrial case and finite element analysis is used to calculate the deformation. In particular, contribution from variation in material properties to the variation in critical points is analyzed. The results indicate that material uncertainties have a small impact on the geometric variation for the test case.
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| 6. |
- Lorin, Samuel C, 1983, et al.
(författare)
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Simulating Geometrical Variation in Injection Molding
- 2010
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Ingår i: Proceedings of NordDesign2010 International Conference on Methods and Tools for Product and Production Development, August 25-27, Gothenburg, Sweden.. - 9789163370649 ; 8:2, s. 395-404
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Konferensbidrag (refereegranskat)
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| 7. |
- Salman, R., et al.
(författare)
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An industrially validated CMM inspection process with sequence constraints
- 2016
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Ingår i: Procedia CIRP. - : Elsevier BV. - 2212-8271. ; 44, s. 138-143
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Konferensbidrag (refereegranskat)abstract
- An efficient CMM inspection process implemented in industry gives significant productivity improvements. A key part of this improvement is the optimization of the inspection sequences. To ensure quality of the inspection the sequences are often constrained with respect to the order of the measurements. This gives rise to so called precedence constraints when modelling the inspection sequence as a variation of the travelling salesperson problem (TSP). Two heuristic solution approaches and a generic optimizing algorithm are considered. A generation based stochastic algorithm is found to reduce cycle time by as much as 12% in comparison to the currently used algorithm.
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| 8. |
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| 9. |
- Segeborn, Johan, 1972, et al.
(författare)
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Load balancing of welds in multi station sheet metal assembly lines
- 2010
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Ingår i: Proceedings of the ASME 2010 International Mechanical Engineering Congress & Exposition, Vancouver, British Columbia, Canada, November 12-18, 2010. - 9780791838914 ; 3:PARTS A AND B, s. 625-630
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Konferensbidrag (refereegranskat)abstract
- The balancing of weld work load between executing stations and its robots has a significant influence on achievable production rate and equipment utilization. However, no automatic simulation based method for line balancing has been formulated up to this point. In practice, it is still manuallyconducted. Therefore in this work we propose two novel methods for load balancing of welds in multi station sheet metal assembly lines to minimize line cycle time. The methods are based on superimposition of the scenes/geometries of all line stations, with maintained robot positioning relative to the work piece, creating a “multi station”. The weld load is balanced between all multi station robots, whereupon the individual robots arecombined into stations and coordinated station wise for simultaneous operation. Furthermore one of the proposed methods reduces the subsequent need for robot coordination, by introducing some restrictions on the load balancing: Firstly, for each robot, the weld load is balanced over the other station robots such that theworking envelopes are maximally separated. Secondly, for each robot, the weld load is balanced over equivalently positioned robots in other line stations, based on previous station load balancing techniques. The proposed line balancing methods are applied on two industrial case studies which each involves the balancing of about 200 automotive stud welds between 3 stations, each of 4 robots. One of the proposed methods produces line cycle times close to that of the slowest uncoordinated robot, which can be considered a theoretical optimum of the line cycle time. Corresponding algorithm running time is about 30 minutes on an Intel Core 2 Quad with 8 GB RAM.
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