| 1. |
|
|
| 2. |
- Gustafsson, Mats, et al.
(författare)
-
Physical bounds on the partial realized gain
- 2010
-
Ingår i: [Host publication title missing]. ; , s. 1-6
-
Konferensbidrag (refereegranskat)abstract
- An antenna identity, derived from the forward scattering sum rule, shows that the partial realized gain of an antenna is related to the polarizability of the antenna structure. The partial realized gain contains the mismatch, directivity, efficiency, and polarization properties of the antenna. The antenna identity expresses how the performance depends on the electrical size and shape of the antenna structure. It is also the starting point for several antenna bounds. In this paper, the identity, its associated physical bounds, and computational aspects of the polarizability dyadics are discussed.
|
|
| 3. |
- Jonsson, Marie, 1979-, et al.
(författare)
-
Force Controlled Assembly of a Compliant Rib
- 2011
-
Ingår i: Proceedings of SEA AeroTech Congress and Exhibition 2011, 18th-21st October, Toulouse, France. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International.
-
Konferensbidrag (refereegranskat)abstract
- Automation in aerospace industry is often in the form of dedicated solutions and focused on processes like drilling, riveting etc. The common industrial robot has due to limitations in positional accuracy and stiffness often been unsuitable for aerospace manufacturing. One major cost driver in aircraft manufacturing is manual assembly and the bespoke tooling needed. Assembly tasks frequently involve setting relations between parts rather than a global need for accuracy. This makes assembly a suitable process for the use of force control. With force control a robot equipped with needed software and hardware, searches for desired force rather than for a position. To test the usefulness of force control for aircraft assembly an experimental case aligning a compliant rib to multiple surfaces was designed and executed. The system used consisted of a standard ABB robot and an open controller and the assembly sequence was made up of several steps in order to achieve final position. The result shows that the process is robust and repetitive and has the potential to reduce the need for bespoke jigs and fixtures.
|
|
| 4. |
- Jonsson, Marie, 1979-, et al.
(författare)
-
Force Feedback for Assembly of Aircraft Structures
- 2010
-
Ingår i: Proceedings of the SAE 2010 Aerospace Manufacturing and Automated Fastening Conference & Exhibition. - SAE International : SAE International.
-
Konferensbidrag (refereegranskat)abstract
- Variability in composite manufacture and the limitations in positional accuracy of common industrial robots have hampered automation of assembly tasks within aircraft manufacturing. One way to handle geometry variations and robot compliancy is to use force control. Force control technology utilizes a sensor mounted on the robot to feedback force data to the controller system so instead of being position driven, i.e. programmed to achieve a certain position with the tool, the robot can be programmed to achieve a certain force. This paper presents an experimental case where a compliant rib is aligned to multiple surfaces using force feedback and an industrial robot system from ABB. Two types of ribs where used, one full size carbon fiber rib, and one smaller metal replica for evaluation purposes. The alignment sequence consisted of several iterative steps and a search procedure was implemented within the robot control system. The technology has the potential to lessen the need for dedicated tooling, reduce the need for traditional workspace calibration and can be used in several other applications, such as pin and socket type assemblies found in pylons or landing gear or “part to part” assemblies such as leading edge ribs to spar.
|
|
| 5. |
- Jonsson, Oskar, et al.
(författare)
-
Experiences of a User-Centred Research Approach involving Old People in Early Phases of Design; Reflections from Furniture Manufacturers
- 2013
-
Ingår i: [Host publication title missing]. ; , s. 1-9
-
Konferensbidrag (refereegranskat)abstract
- The paper concerns the furniture industry’s increased interest in opportunities and challenges to respond to demographic shifts and to meet future senior markets. A central issue discussed is how a user-centred approach in a collaborative design research project benefited the industrial partners. The paper focuses on the perspectives of the participating furniture manufacturers. The most involved representatives from each of the seven participating companies in the project were recruited as respondents. Semi-structured interviews were carried out. The results indicate that a user-centred design research approach with an early focus on old people contributed with knowledge on a general level that benefited the industrial partners. All respondents stated that they were strengthened in their presumptions about old people as furniture users and consumers. The majority stated that their understanding of end users improved. Based on lessons learnt three recommendations for future work in co-operative design research projects are: (1) to establish a mutual understanding of the different roles and perspectives of the design researchers and the industrial partners, (2) involve as many stakeholders as possible and (3) use prototypes and iterative design processes.
|
|
| 6. |
- Jonsson, Sigurdur, et al.
(författare)
-
Monte Carlo studies of protein aggregation
- 2012
-
Ingår i: Physics Procedia. - : Elsevier BV. - 1875-3892. ; 34, s. 49-54
-
Konferensbidrag (refereegranskat)abstract
- The disease-linked amyloid beta (A beta) and alpha-synuclein (alpha S) proteins are both fibril-forming and natively unfolded in free monomeric form. Here, we discuss two recent studies, where we used extensive implicit solvent all-atom Monte Carlo (MC) simulations to elucidate the conformational ensembles sampled by these proteins. For alpha S, we somewhat unexpectedly observed two distinct phases, separated by a clear free-energy barrier. The presence of the barrier makes alpha S, with 140 residues, a challenge to simulate. By using a two-step simulation procedure based on flat-histogram techniques, it was possible to alleviate this problem. The barrier may in part explain why fibril formation is much slower for alpha S than it is for A beta.
|
|
| 7. |
- Jonsson, Vanessa, et al.
(författare)
-
A Scalable Formulation for Engineering Combination Therapies for Evolutionary Dynamics of Disease
- 2014
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- It has been shown that optimal controller synthesis for positive systems can be formulated as a linear program. Leveraging these results, we propose a scalable iterative algorithm for the systematic design of sparse, small gain feedback strategies that stabilize the evolutionary dynamics of a generic disease model. We achieve the desired feedback structure by augmenting the optimization problems with l1 and l2 regularization terms, and illustrate our method on an example inspired by an experimental study aimed at finding appropriate HIV neutralizing antibody therapy combinations in the presence of escape mutants.
|
|
| 8. |
- Stolt, Andreas, et al.
(författare)
-
Force controlled assembly of flexible aircraft structure
- 2011
-
Ingår i: Proceedings - IEEE International Conference on Robotics and Automation. - Shanghai, China : IEEE. ; , s. 6027-6032
-
Konferensbidrag (refereegranskat)abstract
- The use of industrial robots in the aircraft industry has been hampered by a combination of poor accuracy of the robots and poor calibration of the workcell, and also manufacturing variability in composite parts. A way to handle these difficulties is using force control. An experimental case where a semi-compliant rib is aligned to multiple surfaces is used as an example to show this. The constraint-based task specification framework is used for the modelling and control, and the search and alignment sequence required for the assembly is modeled with a state machine. An implementation on an industrial robot system is presented and experimental data is evaluated. The described approach is easy to apply to other fields and more complicated assembly operations as well. © 2011 IEEE.
|
|
