| 1. |
- Andersson, Sarah, et al.
(författare)
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Malmbanan Diaries
- 2010
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This booklet is a report for a case study visit during four day field trip, a group of nine PhD students and their supervisors – all part of the National Research School for Architecture and Planning in the Urban Landscape, APULA – set out to explore what may be considered the outback of Western Europe’s conurbations, the transnational region of Kiruna -Narvik.Both “remote” and “resourceful”, “threatened” and “thriving” (equally relative notions), this region seemed to offer possibilities to reflect upon many of the current tendencies influencing contemporary planning practice and research.
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| 2. |
- Björkelund, Anders, et al.
(författare)
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On the Integration of Skilled Robot Motions for Productivity in Manufacturing
- 2011
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Ingår i: IEEE International Symposium on Assembly and Manufacturing (ISAM), 2011. - 9781612843438 - 9781612843421 ; , s. 1-9
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Konferensbidrag (refereegranskat)abstract
- Robots used in manufacturing today are tailored to their tasks by system integration based on expert knowledge concerning both production and machine control. For upcoming new generations of even more flexible robot solutions, in applications such as dexterous assembly, the robot setup and programming gets even more challenging. Reuse of solutions in terms of parameters, controls, process tuning, and of software modules in general then gets increasingly important. There has been valuable progress within reuse of automation solutions when machines comply with standards and behave according to nominal models. However, more flexible robots with sensor-based manipulation skills and congnitive functions for human inteaction are far too complex to manage, and solutions are rarely reusable since knowledge is either implicit in imperative software or not captured in machine readable form. We propose techniques that build on existing knowledge by converting structured data into an RDF-based knowledge base. By enhancements of industrial control systems and available engineering tools, such knowledge can be gradually extended as part of the interaction during the definition of the robot task.
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| 3. |
- Bengtsson, Johan, et al.
(författare)
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A Robot Playing Scrabble Using Visual Feedback
- 2000
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Ingår i: IFAC Proceedings Volumes. ; 33:27, s. 551-556
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Tidskriftsartikel (refereegranskat)abstract
- Today most industrial robot systems use dedicated and rather limited sensors, and available control systems provide limited support for feedback control. Aiming towards more autonomous robot systems, we want to improve flexibility. The game Scrabble is used as a test problem capturing these aspects. Our approach is to incorporate visual servoing and a conventional powerful off-line prograrnrning (OLP) system into the real-time control system, providing task specification and visual debugging. We use the OLP tool Envision from Deneb and an ABB robot with reconfigured control system, where the control system has an Open Robot Control architecture (ORC). The vision system is connected to a host computer and the camera is attached to the robot gripper. By extending the control system, we have designed and implemented both the vision system and the application for the Scrabble game. Our system implementation shows that ORC constitutes a necessary support for incorporation of real-time visual feedback and that OLP may effectively be used with real-time feedback of sensor data.
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| 4. |
- Bengtsson, Johan, et al.
(författare)
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Modeling of Driver's Longitudinal Behavior
- 2003
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Ingår i: Nonlinear and Hybrid Systems in Automotive Control. - 076801137X ; , s. 41-58
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- In the last years, many vehicle manufacturers have introduced advancedriver support in some of their automobiles. One of those new featuresis Adaptive Cruise Control (ACC), which extends the conventionalcruise control system to control of relative speed and distance toother vehicles. In order to design an ACC controller it is suitable tohave a model on drivers' behavior. Our approach to find dynamicalmodels of the drivers' behavior was to use system identification.Basic data analysis was made by means of system identificationmethodology, and several models of drivers' longitudinal behavior areproposed, including both linear regression models and subspace basedmodels. Detection when a driver is changing his behavior in varioussituations to a deviant behavior is useful. To that purpose a GARCHmodel was used to model the driver in arousal situations, where thedriver changes behavior, is proposed.
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| 5. |
- 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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| 6. |
- Johansson, Bengt, et al.
(författare)
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A Physical Two-Zone NOx Model Intended for Embedded Implementation
- 2009
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Ingår i: SAE Technical Papers. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191.
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Konferensbidrag (refereegranskat)abstract
- This paper offers a two-zone NOx model suitable for vehicle on-board, on-line implementation. Similar NOx modeling attempts have previously been undertaken. The hereby suggested method does however offer clear and important benefits over the previously methods, utilizing a significantly different method to handle temperature calculations within the (two) different zones avoiding iterative computation. The new method significantly improves calculation speed and, most important of all, reduces implementation complexity while still maintaining reasonable accuracy and the physical interpretation of earlier suggested methods. The equations commonly used to compute NOx emissions is also rewritten in order to suit a two-zone NOx model. An algorithm which can be used to compute NOx emissions is presented and the intended contribution of the paper is a NOx model, implementation feasible for an embedded system, e.g. embedded processor or embedded electronic hardware (FPGA). For that purpose parts of the algorithm can be pre-computed and stored in tables allowing significant acceleration of the computation.
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| 7. |
- Pettersson, Anders, et al.
(författare)
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Analysis of Linear L1 Adaptive Control Architectures for Aerospace Applications
- 2012
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Ingår i: IEEE 51st Annual Conference on Decision and Control (CDC), 2012. - 0743-1546. - 9781467320658 ; , s. 1136-1141
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Konferensbidrag (refereegranskat)abstract
- In some situations the closed-loop system obtained by L1 adaptive control is equivalent to linear systems. The architectures of these systems are investigated and compared with internal model control and the input observer architecture. The analysis is focused on aerospace application. An effort has been made to understand and describe what fundamental control characteristic of flying applications that make L1 adaptive controllers suitable for the task.
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| 8. |
- Pettersson, Anders, et al.
(författare)
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Augmenting L1 Adaptive Control of Piecewise Constant Type to a Fighter Aircraft. Performance and Robustness Evaluation for Rapid Maneuvering
- 2012
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Ingår i: AIAA Guidance, Navigation, and Control Conference, 13 - 16 August 2012.
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Konferensbidrag (refereegranskat)abstract
- An L1 adaptive controller of piecewise constant type has been applied to a fighter aircraft by augmenting it to a linear state-feedback controller. Angle of attack and sideslip as well as velocity vector roll rate is demanded and controlled. It is relatively easy to design a controller augmentation this way; few parameters need to be tuned. To design an L1-controller for roll/pitch/yaw-motion of an aircraft, a five-state reference system with desired dynamics is created and three bandwidths of low-pass filters are chosen. The L1-controller activates when the aircraft aided by the feedback controller deviates from the reference dynamics. Load disturbance rejection is improved when the L1-controller is active. Results from simulations with different kinds of deviations from the nominal aircraft are presented. Special non-linear design elements need to be introduced if actuator dynamics, including rate limits, interfere with reference system dynamics. Since an L1 adaptive controller of piecewise constant type in its original form is linear time invariant, frequency domain analysis is presented, including comparisons to a typical linear state-feedback controller.
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| 9. |
- Pettersson, Anders, et al.
(författare)
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Nonlinear Feedforward and Reference Systems for Adaptive Flight Control
- 2013
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Ingår i: 2013 AIAA Guidance, Navigation, and Control Conference. - Reston, Virginia : American Institute of Aeronautics and Astronautics.
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Konferensbidrag (refereegranskat)abstract
- Use of feedforward can alleviate feedback and adaptive actions. Feedforward signals can be generated from reference models and the same models can also be used as reference models in adaptive control. A method for designing the reference models is presented in the paper. By exploiting the structure of the equations describing air vehicles it is possible to find reference models that scale to the present flight condition and vehicle configuration. Such reference systems are derived for flying vehicles in a generic manner, suitable for both winged aircraft and missiles. The same type of reference systems are also used to create trajectories for feedforward signals that compensate known plant non-linearities.
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| 10. |
- 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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