| 1. |
- 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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| 2. |
- Olsson, Jan-Ola, et al.
(författare)
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Closed-loop System Identification of an HCCI Engine
- 2004
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Ingår i: Advances in Automotive Control. - 0080442501 ; 37:22, s. 239-244
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Konferensbidrag (refereegranskat)abstract
- Homogeneous Charge Compression Ignition (HCCI) is a promising but challenging combustion engine concept. The potential for good fuel economy and low emissions is high but the transient performance required for automotive applications presents a few problems still to be solved. The focus of this work is identification of the process dynamics. An ARX type model is fitted to input-output data. A method applicable under closed-loop control is suggested and demonstrated. The resulting models are evaluated in terms of the repeatability of model characteristics, prediction accuracy, residual characteristics and comparison to spectral models is made.
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| 3. |
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| 4. |
- Pfeiffer, Roland, et al.
(författare)
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System Identification and LQG Control of Variable-Compression HCCI Engine Dynamics
- 2004
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Ingår i: Proceedings of the 2004 IEEE International Conference on Control Applications.. - 1085-1992. - 0780386337 ; 2, s. 1442-1447
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Konferensbidrag (refereegranskat)abstract
- The Homogenous Charge Compression Ignition (HCCI) combustion engine has potential to replace the spark ignition and compression ignition engines of today. One of the main problems in making the engine commercially attractive is the lack of direct means of controlling the ignition phasing. In this paper, we investigate the potential of inlet air temperature as a means to ignition actuation. This article describes a method for system identification of the HCCI process, and development of an effective LQG regulator for the combustion process, Matlab and Simulink being used in computations and simulations.
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| 5. |
- Carlson, Jonas, et al.
(författare)
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Classification of Electrocardiographic P-wave Morphology
- 2001
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Ingår i: IEEE Transactions on Biomedical Engineering. - : Institute of Electrical and Electronics Engineers (IEEE). - 1558-2531 .- 0018-9294. ; 48:4, s. 401-405
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Tidskriftsartikel (refereegranskat)abstract
- The atrial activity of the human heart is normally visible in the electrocardiogram as a P-wave. In patients with intermittent atrial fibrillation, a different P-wave morphology can sometimes be seen, indicating atrial conduction defects. The purpose of this study was to develop a method to discriminate between such P-waves and normal ones. 20 recordings of each type were used in a classification which, based on impulse response analysis of the P-wave and linear discrimination between various parameters, produced a correct classification in 37 of the 40 recordings (sensitivity 95%, specificity 90%)
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| 6. |
- 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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| 7. |
- Olsson, Tomas, et al.
(författare)
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Flexible Force-Vision Control for Surface Following using Multiple Cameras
- 2004
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Ingår i: Proceedings. 2004 IEEE/RSJ International Conference on Intelligent Robots and Systems, 2004. (IROS 2004).. - 0780384636 ; 1, s. 789-803
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Konferensbidrag (refereegranskat)abstract
- A flexible method for six-degree-of-freedom combined vision/force control for interaction with a stiff uncalibrated environment is presented. An edge-based rigidbody tracker is used in an observer-based controller, and combined with a six-degree-of-freedom force- or impedance controller. The effect of error sources such as image space measurement noise and calibration errors are considered. Finally, the method is validated in simulations and a surface following experiment using an industrial robot.
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| 8. |
- Olsson, Tomas, et al.
(författare)
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Force Control and Visual Servoing Using Planar Surface Identification
- 2002
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Ingår i: Proceedings. ICRA '02.. - 0780372727 ; 4, s. 4211-4216
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Konferensbidrag (refereegranskat)abstract
- When designing flexible multi-sensor based robot systems, one important problem is how to combine the measurements fromdisparate sensors such as cameras and force sensors. In this paper,we present a method for combining direct force control and visualservoing in the presence of unknown planar surfaces. The controlalgorithm involves a force feedback control loop and a vision basedreference trajectory as a feed-forward signal. The vision system isbased on a constrained image-based visual servoing algorithm designedfor surface following, wherethe location and orientation of the planar constraint surface is estimated online using position-, force- and visual data.We show how data from a simple and efficient camera calibration method can be used in combination withforce and position data to improve the estimation and referencetrajectories.The method is validated through experiments involving force controlleddrawing on an unknown surface. The robot will grasp a pen and use itto draw lines between a number of markers drawn ona white-board, while the contact force is kept constant. Despite its simplicity, the performance of the method is satisfactory.
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| 9. |
- Olsson, Tomas, et al.
(författare)
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Visual Position Tracking using Dual Quaternions with Hand-Eye Motion Constraints
- 2003
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Ingår i: Proceedings. ICRA '03.. - 2152-4092 .- 1050-4729. - 0780377362 ; 3, s. 3491-3496
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Konferensbidrag (refereegranskat)abstract
- In this paper a method for contour-based rigid body tracking with simultaneouscamera calibration is developed. The method works for a singleeye-in-hand camera with unknown hand-eye transformation,viewing a stationary object with unknown position. The method usesdual quaternions to express the relationship between the camera- andend-effector screws. It is shown how using the measured motion of therobot end-effector can improve the accuracy of theestimation, even if the relative position and orientation between sensorand actuator is completely unknown.The method is evaluated in simulations on images from a real-time 3D renderingsystem. The system is shown to be able to track the pose of rigid objects and changes in intrinsic camera parameters, using only rough initial values for the parameters. The method is finally validated in anexperiment using real images from a camera mounted on an industrial robot.
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| 10. |
- Tunestål, Per, et al.
(författare)
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Closed-Loop Combustion Control of HCCI Engines
- 2003
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Ingår i: Nonlinear and Hybrid Systems in Automotive Control. ; , s. 321-334
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- The HCCI engine, with its excellent potential for high efficiency and low NOx emissions, is investigated from a control perspective. Combustion timing, i.e., where in the thermodynamic cycle combustion takes place, is identified as the most challenging problem with HCCI engine control. A number of different means for controlling combustion timing are suggested, and results using a dual-fuel solution are presented. This solution uses two fuels with different ignition characteristics to control the time of autoignition. Cylinder pressure measurement is suggested for feedback of combustion timing. A simple net-heat release algorithm is applied to the measurements, and the crank angle of 50% burnt is extracted. Open-loop instability is detected in some high-load regions of the operating range. This phenomenon is explained by positive feedback between the cylinder wall heating and ignition timing processes. Closed-loop performance is hampered by time delays and model uncertainties. This problem is particularly pronounced at operating points that are open-loop unstable.
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