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Nordin, Peter
Publications (10 of 11) Show all publications
Nordin, P., Braun, R. & Krus, P. (2015). Job-Scheduling of Distributed Simulation-Based Optimization with Support for Multi-Level Parallelism. In: Proceedings of the 56th Conference on Simulation and Modelling (SIMS 56): October, 7-9, 2015, Linköping University, Sweden. Paper presented at The 56th Conference on Simulation and Modelling (SIMS 56), “Modelling, Simulation and Optimization”, Linköping, Sweden, 7-9 October 2015 (pp. 187-197). Linköping: Linköping University Electronic Press
Open this publication in new window or tab >>Job-Scheduling of Distributed Simulation-Based Optimization with Support for Multi-Level Parallelism
2015 (English)In: Proceedings of the 56th Conference on Simulation and Modelling (SIMS 56): October, 7-9, 2015, Linköping University, Sweden, Linköping: Linköping University Electronic Press, 2015, p. 187-197Conference paper, Published paper (Refereed)
Abstract [en]

In many organizations, the utilization of available computer power is very low. If it could be harnessed for parallel simulation and optimization, valuable time could be saved. A framework monitoring available computer resources and running distributed simulations is proposed. Users build their models locally, and then let a job scheduler determine how the simulation work should be divided among remote computers providing simulation services. Typical applications include sensitivity analysis, co-simulation and design optimization. The latter is used to demonstrate the framework. Optimizations can be parallelized either across the algorithm or across the model. An algorithm for finding the optimal distribution of the different levels of parallelism is proposed. An initial implementation of the framework, using the Hopsan simulation tool, is presented. Three parallel optimization algorithms have been used to verify the method and a thorough examination of their parallel speed-up is included.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2015
Series
Linköping Electronic Conference Proceedings, ISSN 1650-3686, E-ISSN 1650-3740 ; 119
Keywords
Job-scheduling, parallelism, distributed simulation, optimization
National Category
Electrical Engineering, Electronic Engineering, Information Engineering Fluid Mechanics and Acoustics
Identifiers
urn:nbn:se:liu:diva-122752 (URN)10.3384/ecp15119187 (DOI)9789176859001 (ISBN)
Conference
The 56th Conference on Simulation and Modelling (SIMS 56), “Modelling, Simulation and Optimization”, Linköping, Sweden, 7-9 October 2015
Available from: 2015-11-19 Created: 2015-11-19 Last updated: 2018-02-02Bibliographically approved
Krus, P., Braun, R., Nordin, P. & Eriksson, B. (2012). Aircraft System Simulation for Preliminary Design. In: Professor I Grant (Ed.), ICAS 2012 CD-ROM PROCEEDINGS: . Paper presented at 28th International Congress of the Aeronautical Sciences, Brisbane, Australia, 23 - 28 September, 2012 (pp. Art.nr. ICAS2012-1.9.3). Optimage Ltd
Open this publication in new window or tab >>Aircraft System Simulation for Preliminary Design
2012 (English)In: ICAS 2012 CD-ROM PROCEEDINGS / [ed] Professor I Grant, Optimage Ltd , 2012, p. Art.nr. ICAS2012-1.9.3-Conference paper, Published paper (Other academic)
Abstract [en]

Developments in computational hardware and simulation software have come to a point where it is possible to use whole mission simulation in a framework for conceptual/preliminary design. This paper is about the implementation of full system simulation software for conceptual/preliminary aircraft design. It is based on the new Hopsan NG simulation package, developed at the Linköping University. The Hopsan NG software is implemented in C++. Hopsan NG is the first simulation software that has support for multi-core simulation for high speed simulation of multi domain systems.

In this paper this is demonstrated on a flight simulation model with subsystems, such as control surface actuators.

Place, publisher, year, edition, pages
Optimage Ltd, 2012
Keywords
aircraft conceptual design, sy stem modeling, mission simulation
National Category
Software Engineering
Identifiers
urn:nbn:se:liu:diva-121484 (URN)978-0-9565333-1-9 (ISBN)
Conference
28th International Congress of the Aeronautical Sciences, Brisbane, Australia, 23 - 28 September, 2012
Funder
VINNOVA
Available from: 2015-09-22 Created: 2015-09-22 Last updated: 2018-01-11Bibliographically approved
Nordin, P. (2012). Mobile Robot Traversability Mapping: For Outdoor Navigation. (Licentiate dissertation). Linköping: Linköping University Electronic Press
Open this publication in new window or tab >>Mobile Robot Traversability Mapping: For Outdoor Navigation
2012 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

To avoid getting stuck or causing damage to a vehicle or its surroundings a driver must be able to identify obstacles and adapt speed to ground conditions. An automatically controlled vehicle must be able to handle these identifications and adjustments by itself using sensors, actuators and control software. By storing properties of the surroundings in a map, a vehicle revisiting an area can benefit from prior information.

Rough ground may cause oscillations in the vehicle chassis. These can be measured by on-board motion sensors. For obstacle detection, a representation of the geometry of the surroundings can be created using range sensors. Information on where it is suitable to drive, called traversability, can be generated based on these kinds of sensor measurements.

In this work, real semi-autonomous mobile robots have been used to create traverasbility maps in both simulated and real outdoor environments. Seeking out problems through experiments and implementing algorithms in an attempt to solve them has been the core of the work.

Finding large obstacles in the vicinity of a vehicle is seldom a problem; accurately identifying small near-ground obstacles is much more difficult, however. The work additionally includes both high-level path planning, where no obstacle details are considered, and more detailed planning for finding an obstacle free path. How prior maps can be matched and merged in preparation for path planning operations is also shown. To prevent collisions with unforeseen objects, up-to-date traversability information is used in local-area navigation and obstacle avoidance.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2012. p. 122
Series
Linköping Studies in Science and Technology. Thesis, ISSN 0280-7971 ; 1564
Keywords
Traversability, Laser, Roughness, Mapping, Planning, Mobile robot, Navigation, Implementation
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-85937 (URN)LIU-TEK-LIC-2012:49 (Local ID)978-91-7519-726-5 (ISBN)LIU-TEK-LIC-2012:49 (Archive number)LIU-TEK-LIC-2012:49 (OAI)
Presentation
2012-12-14, A39, A-huset, Campus Valla, Linköpings universitet, Linköping, 14:15 (English)
Opponent
Supervisors
Available from: 2012-12-03 Created: 2012-12-03 Last updated: 2012-12-06Bibliographically approved
Braun, R., Nordin, P., Eriksson, B. & Krus, P. (2011). High Performance System Simulation Using Multiple Processor Cores. In: Harri Sairiala & Kari T. Koskinen (Ed.), The Twelfth Scandinavian International Conference on Fluid Power, SICFP'11: . Paper presented at The Twelfth Scandinavian International Conference on Fluid Power, SICFP'11, 18th–20th May, Tampere, Finland.
Open this publication in new window or tab >>High Performance System Simulation Using Multiple Processor Cores
2011 (English)In: The Twelfth Scandinavian International Conference on Fluid Power, SICFP'11 / [ed] Harri Sairiala & Kari T. Koskinen, 2011Conference paper, Published paper (Refereed)
Abstract [en]

Future research and development will depend on high-speed simulations, especially for large and complex systems. Rapid prototyping, optimization and real-time simulations require  simulation tools that can take full advantage of  computer hardware.  Recent developments  in the computer market indicate  a change in focus from increasing the speed of processor cores towards increasing the number of cores in each processor. HOPSAN is a simulation tool for fluid power and mechatronics, developed at Linköping University. It  is based upon the transmission line  modeling  (TLM)  technique. This method is very suitable for taking advantage of multi-core  processors.  This paper presents  the  implementation  of multi-core support in the next generation of HOPSAN. The concept is to divide the  model  into equally sized  groups of  independent components,  to make it possible to  simulate  them  in separate threads. Reducing overhead costs and finding an effective sorting algorithm constitute  critical steps for maximizing the benefits.  Experimental results show  a significant reduction in simulation time. Improvement of algorithms in combination with a continuous increase in the number of processor cores can potentially  lead to further  increases  in simulation performance. 

Keywords
Multi-core, simulation, transmission line element method, transmission line modelling, fluid power, system simulation
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-68373 (URN)978-952-15-2517-9 (ISBN)978-952-15-2520-9 (ISBN)978-952-15-3273-3 (ISBN)
Conference
The Twelfth Scandinavian International Conference on Fluid Power, SICFP'11, 18th–20th May, Tampere, Finland
Available from: 2011-05-23 Created: 2011-05-23 Last updated: 2016-04-07
Nordin, P. & Degerman, P. (2011). Multi Layered Maps for Enhanced Environmental Perception. Paper presented at SAE 2011 Commercial Vehicle Engineering Congress, 13-14 September 2011, Rosemont, Illinois USA.
Open this publication in new window or tab >>Multi Layered Maps for Enhanced Environmental Perception
2011 (English)Conference paper, Published paper (Other academic)
Abstract [en]

Traditionally, an in-vehicle map consists of only one type of data, tailored for a single user function. For example, the navigation maps contain spatial information about the roads. On the other hand, a map built for adaptive cruise control use consists of the detected vehicles and their properties. In autonomous vehicle research, the maps are often built up as an occupancy grid where areas are classified as passable or impassable. Using these kinds of maps separately, however, is not enough to support the traffic safety enhancing and advanced driver assistance systems of today and tomorrow.

Instead of using separate systems to handle individual safety or planning tasks, information could be stored in one shared map containing several correlated layers of information. Map information can be collected by any number of different sensor devices, and fusion algorithms can be used to enhance the quality of the information. User functions that base their decisions on the multi-layered map can then retrieve any subset of the stored information making them scalable in terms of processor and memory use.

The advantages of using a shared multi-layer spatial data storage are several:

Sensors and user functions are decoupled. This can make it easier and more cost efficient to implement additional functions.

Data quality is enhanced. Since fusion techniques can be used to generate estimates of physical properties from several sensors, the fused data is based on all available information.

Using models that describe a certain entity, properties that are not even measured can be estimated by the system.

This work describes an experimental semi-autonomous ground vehicle system, where on-line generated maps containing multiple layers of information are used for obstacle avoidance and planning of a suitable path between waypoints. The system is primarily simulated using physical vehicle models in a suitable environment, but limited real-world experiments with a subset of functions are also performed. 

National Category
Robotics Vehicle Engineering
Identifiers
urn:nbn:se:liu:diva-70851 (URN)10.4271/2011-01-2244 (DOI)
Conference
SAE 2011 Commercial Vehicle Engineering Congress, 13-14 September 2011, Rosemont, Illinois USA
Available from: 2011-09-20 Created: 2011-09-20 Last updated: 2012-12-03Bibliographically approved
Eriksson, B., Nordin, P. & Krus, P. (2010). Hopsan NG, A C++ Implementation using the TLM Simulation Technique. In: sko Juuso (Ed.), SIMS 2010 Proceedings, The 51st Conference on Simulation and Modelling, 14-15 October 2010 Oulu, Finland: . Paper presented at Conference of Scandinavian Simulation Society, sims’10, 14th–15th October, Oulu, Finland. Oulu, Finland
Open this publication in new window or tab >>Hopsan NG, A C++ Implementation using the TLM Simulation Technique
2010 (English)In: SIMS 2010 Proceedings, The 51st Conference on Simulation and Modelling, 14-15 October 2010 Oulu, Finland / [ed] sko Juuso, Oulu, Finland, 2010Conference paper, Published paper (Refereed)
Abstract [en]

The Hopsan simulation package, used primarily for hydro-mechanical simulation, was first released in 1977. Modeling in Hopsan is based on a method using transmission line modeling, TLM. In TLM, component models are decoupled from each other through time delays. As components are decoupled and use distributed solvers, the simulation environment is suitable for distributed simulations. No numerical errors are introduced at simulation time when using TLM; all errors are related to modeling errors. This yields robust and fast simulations where the size of the time step does not have to be adjusted to achieve a numerically stable simulation. The distributive nature of TLM makes it convenient for use in multi-core approaches and high speed simulations. The latest version of Hopsan was released in August 2002, but now the next generation of this simulation package is being developed. This paper presents the development version of Hopsan NG and discusses some of its features and possible uses.

Place, publisher, year, edition, pages
Oulu, Finland: , 2010
Keywords
Hopsan, TLM, transmission lines, distributed modeling, distributed solvers
National Category
Other Computer and Information Science
Identifiers
urn:nbn:se:liu:diva-60644 (URN)9789525183429 (ISBN)
Conference
Conference of Scandinavian Simulation Society, sims’10, 14th–15th October, Oulu, Finland
Projects
HiPO
Available from: 2010-10-21 Created: 2010-10-21 Last updated: 2018-10-10Bibliographically approved
Nordin, P. & Nygårds, J. (2010). Local Navigation using Traversability Maps. In: Indiveri, Giovanni, Pascoal, Antonio M. (Ed.), 7th Symposium on Intelligent Autonomous Vehicles, IAV2010, Lecce, Volume 7, Part 1: . Paper presented at Intelligent Autonomous Vehicles, September 6-8, University of Salento, Lecce, Italy, Volume7, Part 1 (pp. 324-329).
Open this publication in new window or tab >>Local Navigation using Traversability Maps
2010 (English)In: 7th Symposium on Intelligent Autonomous Vehicles, IAV2010, Lecce, Volume 7, Part 1 / [ed] Indiveri, Giovanni, Pascoal, Antonio M., 2010, p. 324-329Conference paper, Published paper (Refereed)
Abstract [en]

In outdoor robotics it is important to be able to ascertain the traversability of thes urrounding terrain. This paper presents a system where continuously generated traversability maps, useful for obstacle avoidance, are generated, stored and later reused to perform detailed local path planning. The detailed plan can be used as a temporary replacement for parts of a global plan that may lack knowledge about impassable obstacles or troublesome areas. The paper also describes an algorithm useful for on-line alignment and merging of previously stored traversability maps. Being able to align and merge maps is vital as the estimated global poses of multiple overlapping maps stored at different times may differ.

Keywords
Obstacle avoidance, local navigation, traversability, path planning
National Category
Control Engineering
Identifiers
urn:nbn:se:liu:diva-60739 (URN)10.3182/20100906-3-IT-2019.00057 (DOI)978-3-902661-87-6 (ISBN)
Conference
Intelligent Autonomous Vehicles, September 6-8, University of Salento, Lecce, Italy, Volume7, Part 1
Available from: 2010-10-25 Created: 2010-10-25 Last updated: 2014-09-22
Axin, M., Braun, R., Dell'Amico, A., Eriksson, B., Nordin, P., Pettersson, K., . . . Krus, P. (2010). Next Generation Simulation Software using Transmission Line Elements. In: Dr D N Johnston and Professor A R Plummer (Ed.), Fluid Power and Motion Control: . Paper presented at Fluid Power and Motion Control, 15th-17th September, Bath, England, UK (pp. 265-276). Centre for Power Transmission and Motion Control
Open this publication in new window or tab >>Next Generation Simulation Software using Transmission Line Elements
Show others...
2010 (English)In: Fluid Power and Motion Control / [ed] Dr D N Johnston and Professor A R Plummer, Centre for Power Transmission and Motion Control , 2010, p. 265-276Conference paper, Published paper (Refereed)
Abstract [en]

A suitable method for simulating large complex dynamic systems is represented by distributed modelling using transmission line elements. The method is applicable to all physical systems, such as mechanical, electrical and pneumatics, but is particularly well suited to simulate systems where wave propagation is an important issue, for instance hydraulic systems. By using this method, components can be numerically isolated from each other, which provide highly robust numerical properties. It also enables the use of multi-core architecture since a system model can be composed by distributed simulations of subsystems on different processor cores.

Technologies based on transmission lines has successfully been implemented in the HOPSAN simulation package, develop at Linköping University. Currently, the next generation of HOPSAN is developed using an object-oriented approach. The work is focused on compatibility, execution speed and real-time simulation in order to facilitate hardware-in-the-loop applications. This paper presents the work progress and some possible features in the new version of the HOPSAN simulation package.

Place, publisher, year, edition, pages
Centre for Power Transmission and Motion Control, 2010
National Category
Mechanical Engineering
Identifiers
urn:nbn:se:liu:diva-59661 (URN)978-1-86197-181-4 (ISBN)
Conference
Fluid Power and Motion Control, 15th-17th September, Bath, England, UK
Projects
HiPO
Available from: 2010-11-08 Created: 2010-09-23 Last updated: 2016-05-27Bibliographically approved
Nordin, P., Andersson, L. & Nygårds, J. (2009). Results of the TAIS/preRunners-project. In: Lars Asplund (Ed.), Fourth Swedish Workshop on Autonomous Robotics SWAR'09. Paper presented at Fourth Swedish Workshop on Autonomous Robotics SWAR'09, Västerås, Sweden, September 8 (pp. 60-61).
Open this publication in new window or tab >>Results of the TAIS/preRunners-project
2009 (English)In: Fourth Swedish Workshop on Autonomous Robotics SWAR'09 / [ed] Lars Asplund, 2009, p. 60-61Conference paper, Published paper (Refereed)
Abstract [en]

This paper presents selected results of the preRunners project. The goal was to experimentally demonstrate the value of collaborating unmanned ground vehicles (UGVs) in an outdoor setting. With uneven terrain and unexpected obstacles a large vehicle benefits greatly from a priori information about theterrain ahead. This information can be gathered by a smaller, more agile and risk tolerant autonomous “preRunner”.

Keywords
Outdoor robotics, Mapping, Traversability, SLAM, C-SLAM
National Category
Information Systems
Identifiers
urn:nbn:se:liu:diva-52684 (URN)
Conference
Fourth Swedish Workshop on Autonomous Robotics SWAR'09, Västerås, Sweden, September 8
Projects
PreRunners
Available from: 2010-01-08 Created: 2010-01-08 Last updated: 2018-01-12Bibliographically approved
Nordin, P., Andersson, L. & Nygårds, J. (2008). Sensor Data Fusion for Terrain Exploration by Collaborating Unmanned Ground Vehicles. In: Proceedings of the 11th International Conference on Information Fusion, FUSION 2008, Cologne, Germany, 30th June–3rd July: . Paper presented at 11th International Conference on Information Fusion, FUSION 2008, Cologne, Germany, 30th June–3rd July (pp. 1214-1221). IEEE Xplore
Open this publication in new window or tab >>Sensor Data Fusion for Terrain Exploration by Collaborating Unmanned Ground Vehicles
2008 (English)In: Proceedings of the 11th International Conference on Information Fusion, FUSION 2008, Cologne, Germany, 30th June–3rd July, IEEE Xplore , 2008, p. 1214-1221Conference paper, Published paper (Refereed)
Abstract [en]

This paper presents work in progress for the pre-Runners project. The goal is to experimentally demonstrate the value of unmanned ground vehicles (UGVs) in collaboration with a main vehicle in an outdoor setting. With uneven terrain and unexpected obstacles the main vehicle benefits from a priori information of the terrain ahead. This information can be gathered by a smaller, more agile, and risks tolerant autonomous “prerunner”. The results presented, represent the first steps toward the important task of determining the traversable surfaces and communicating the results within the team. The information sharing between vehicles is based on Collaborative Smoothing and Mapping (C-SAM). The horizontal position is also estimated within the C-SAM. In parallel the vertical component and orientation is estimated by a filter fusing data from odometry, an imu and two lasers to allow computation of traversability maps to be shared within the team.

Place, publisher, year, edition, pages
IEEE Xplore, 2008
Keywords
Collaboration, SLAM, SAM, sensor data fusion, data association, Kalman filtering, traversability estimation
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-15323 (URN)978-3-8007-3092-6 (ISBN)
Conference
11th International Conference on Information Fusion, FUSION 2008, Cologne, Germany, 30th June–3rd July
Note

DOI does not work: 10.1109/ICIF.2008.4632348

Available from: 2008-10-31 Created: 2008-10-31 Last updated: 2018-03-09Bibliographically approved
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