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| 2. |
- Berner, Josefin, et al.
(författare)
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Improved Relay Autotuning using Normalized Time Delay
- 2016
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Ingår i: American Control Conference (ACC), 2016.
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Konferensbidrag (refereegranskat)abstract
- The relay autotuner provides a simple way offinding PID controllers of sufficient performance. By usingan asymmetric relay function the excitation of the process isimproved. This gives better models, and hence a better tuning,without increasing the time consumption or complexity of theexperiment. Some processes demand more accurate modelingand tuning to obtain controllers of sufficient performance.These processes can be singled out by their normalized timedelays and be subject to further modeling efforts. The autotunerproposed in this paper provides a simple way of findingthe normalized time delay from the experiment, and uses itfor model and controller selection. The autotuner has beenimplemented and evaluated both in a simulation environmentand by industrial experiments.
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| 3. |
- Berner, Josefin, et al.
(författare)
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Practical Evaluation of a Novel Multivariable Relay Autotuner with Short and Efficient Excitation
- 2017
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Ingår i: IEEE Conference on Control Technology and Applications, CCTA 2017. ; , s. 1505-1510
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Konferensbidrag (refereegranskat)abstract
- In this paper we propose an autotuning method that combines a setup for decentralized relay autotuning of two-input two-output systems with an identification method that uses short experiments to estimate up to second-ordertime-delayed systems. A small modification of the experiment gives better low-frequency excitation and improved models. The method is successfully demonstrated in simulations and on a quadruple tank process.
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| 4. |
- Berner, Josefin, et al.
(författare)
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Towards a New Generation of Relay Autotuners
- 2014
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Ingår i: 19th IFAC World Congress, 2014.
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Konferensbidrag (refereegranskat)abstract
- The relay autotuner for PID control is based on the simple idea of investigating process dynamics by the oscillation obtained when the PID controller is replaced by a relay unction. In this paper an asymmetric relay function is used, which provides an equation for the static gain of the process. A method to find the normalized time delay is proposed and the benefits of this is discussed. Ways to find low-order models from the experiment are described. Considerations of how to choose the relay parameters are made and some examples are given.
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| 5. |
- Bernhardsson, Bo, et al.
(författare)
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A Stabilizing Switching Scheme for Multi Controller Systems
- 1996
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Ingår i: IFAC Proceedings Volumes. ; 29, s. 2627-2632
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Konferensbidrag (refereegranskat)abstract
- The stability of a multi-controller system is analyzed using Lyapunov theory. Stability is guaranteed by a switching strategy determined by a combination of separate Lyapunov functions for the different controllers. The behavior on sliding surfaces is analyzed using non-smooth analysis according to Filippov. Two examples illustrate the theory.
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| 6. |
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| 7. |
- Burgner, Chris, et al.
(författare)
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Digital Control of Tunneling Accelerometer
- 2009
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Ingår i: 2009 IEEE Sensors. ; , s. 1824-1827
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Konferensbidrag (refereegranskat)abstract
- A controller for a tunneling accelerometer has two tasks: to establish tunneling and to maintain tunneling during acceleration. This paper describes the design and implementation of a digital controller that accomplishes these tasks and provides the appropriate gain switching. The control law is based on a standard configuration of an observer and state feedback. A digital controller is implemented because the controller parameters can be easily adjusted, thereby allowing for rapid prototyping. The design methodology presented here can be used as a general plug-and-play controller platform for a range of MEMS sensors. The performance of the digital controller is illustrated experimentally using metrics such as tracking response, drift, noise floor and response linearity.
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| 8. |
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| 9. |
- Cervin, Anton, et al.
(författare)
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On Limit Cycles in Event-Based Control Systems
- 2007
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Ingår i: 46th IEEE Conference on Decision and Control, 2007. ; , s. 1947-1952
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Konferensbidrag (refereegranskat)abstract
- Event-based control is a promising alternative to time-triggered control, especially for systems with limited computation and communication capacities. In the paper, the architecture of a general structure for event-based control is presented. The resulting system has many interesting properties. For instance, a constant load disturbance will typically make the process output oscillate according to a stable limit cycle. Necessary conditions for the limit cycle are given and its local stability is analyzed. Finally, a simple way to achieve integral action based on times between events is proposed.
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