| 1. |
- Andersson, Ingemar, et al.
(författare)
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A Parametric Model for Ionization Current in a Four Stroke SI Engine
- 2009
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Ingår i: JOURNAL OF DYNAMIC SYSTEMS MEASUREMENT AND CONTROL-TRANSACTIONS OF THE ASME. - : ASME International. - 0022-0434 .- 1528-9028. ; 131:2, s. 021001-
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Tidskriftsartikel (refereegranskat)abstract
- A model for the thermal part of an ionization signal is presented that connects the ionization current to cylinder pressure and temperature in a spark ignited internal combustion engine. One strength of the model is that, after calibration, it has only two free parameters: burn angle and initial kernel temperature. By fitting the model to a measured ionization signal, it is possible to estimate both cylinder pressure and temperature, where the pressure is estimated with good accuracy. The model approach is validated on engine data. Cylinder pressure and ionization current data were collected on a Saab four-cylinder spark ignited engine for a variation in ignition timing and air-fuel ratio. The main result is that the parametrized ionization current model can be used to estimating combustion properties as pressure, temperature, and content of nitric oxides based on measured ionization currents. The current status of the model is suitable for off-line analysis of ionization currents and cylinder pressure. This ionization current model not only describes the connection between the ionization current and the combustion process, but also offers new possibilities for engine management system to control the internal combustion engine.
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| 2. |
- Andersson, Ingemar, 1969, et al.
(författare)
-
A Parametric Model for Ionization Current in a Four Stroke SI Engine
- 2009
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Ingår i: Journal of Dynamic Systems, Measurement and Control, Transactions of the ASME. - 0022-0434 .- 1528-9028. ; 131:2, s. 1-11
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Tidskriftsartikel (refereegranskat)abstract
- A model for the thermal part of an ionization signal is presented that connects the ionization current to cylinder pressure and temperature in a spark ignited internal combustion engine. One strength of the model is that it after calibration has only two free parameters, burn angle and initial kernel temperature. By fitting the model to a measured ionization signal it is possible to estimate both cylinder pressure and temperature, where the pressure is estimated with good accuracy. The model approach is validated on engine data. Cylinder pressure and ionization current data was collected on a Saab 4-cylinder SI engine for a variation in ignition timing and air-fuel ratio.The main result is that the parameterized ionization current model can be used to estimating combustion properties as pressure, temperature and contentof nitric oxides based on measured ionization currents.The current status of the model is suitable for off-line analysis of ionization currents and cylinder pressure.This ionization current model not only describes the connection between the ionization current and the combustion process, it also offers new possibilities for EMS to control the internal combustion engine.
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| 3. |
- Carvalho Bittencourt, André, et al.
(författare)
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Static Friction in a Robot Joint : Modeling and Identification of Load and Temperature Effects
- 2012
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Ingår i: Journal of Dynamic Systems Measurement, and Control. - : American Society of Mechanical Engineers (ASME). - 0022-0434 .- 1528-9028. ; 134:5
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Tidskriftsartikel (refereegranskat)abstract
- Friction is the result of complex interactions between contacting surfaces in down to a nanoscale perspective. Depending on the application, the different models available are more or less suitable. Static friction models are typically considered to be dependent only on relative speed of interacting surfaces. However, it is known that friction can be affected by other factors than speed.In this paper, the typical friction phenomena and models used in robotics are reviewed. It is shown how such models can be represented as a sum of functions of relevant states which are linear and nonlinear in the parameters, and how the identification method described in Golub and Pereyra (1973) can be used to identify them when all states are measured. The discussion follows with a detailed experimental study of friction in a robot joint under changes of joint angle, load torque and temperature. Justified by their significance, load torque and temperature are included in an extended static friction model. The proposed model is validated in a wide operating range, considerably improving the prediction performance compared to a standard model.
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| 4. |
- Deosthale, Eeshan, et al.
(författare)
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Discrete Fault Diagnosis of Structurally Reconfigurable Systems
- 2021
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Ingår i: Journal of Dynamic Systems Measurement, and Control. - : ASME. - 0022-0434 .- 1528-9028. ; 143:10
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Tidskriftsartikel (refereegranskat)abstract
- Fault diagnosis of a certain class of hybrid systems referred to as structurally reconfigurable (SR) systems is complicated. This is because SR systems tend to switch their configuration, which may or may not be faulty. It is important to identify the mode of the SR system along with the corresponding fault if any, in order to facilitate a fault tolerant action. This paper combines discrete fault diagnosis with mode identification for SR systems to achieve two main objectives: Sensor selection for fault detection, isolation and mode identification, and residual selection for mode identification. The framework is built using a structural analysis-based approach to meet these objectives. This framework is demonstrated for a 10-speed Automatic Transmission, which is an illustrative example of SR systems.
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| 5. |
- Ekström, Rickard, et al.
(författare)
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Evaluating Constant DC-Link Operation of Wave Energy Converter
- 2014
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Ingår i: Journal of Dynamic Systems Measurement, and Control. - : ASME International. - 0022-0434 .- 1528-9028. ; 136:1, s. 014501-
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Tidskriftsartikel (refereegranskat)abstract
- A wave energy converter (WEC) based on a linear generator and a point-absorbing buoy has been developed at Uppsala University. Interconnecting an array of WECs in parallel requires a point of common coupling, such as a common dc-bus. The dc voltage level seen by the generator is directly linked to the electromagnetic damping of the generator. A lower dc-level results in a higher damping factor and is important for increased absorption of the wave power. The drawback is increased losses in generator windings and cable resistance. There will be an optimal dc-level for maximum power output. This is a function of not only generator and buoy characteristics, but the current sea state. Experimental results of the full-scale system have been carried out, and used as validation of a simulation model of the system. The model is then used to evaluate how the dc-level seen by the generator influence the power output. The results indicate that higher dc-levels should be used at higher sea states, and power output may vary by up to a factor five depending on which dc-level is chosen.
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| 6. |
- Fors, Victor, 1990-, et al.
(författare)
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Predictive Force-Centric Emergency Collision Avoidance
- 2021
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Ingår i: Journal of Dynamic Systems, Measurement, and Control, ASME. - : ASME International. - 0022-0434 .- 1528-9028. ; 143:8, s. 081005-081005
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Tidskriftsartikel (refereegranskat)abstract
- A controller for critical vehicle maneuvering is proposed that avoids obstacles and keeps the vehicle on the road while achieving heavy braking. It operates at the limit of friction and is structured in two main steps: a motion-planning step based on receding-horizon planning to obtain acceleration-vector references, and a low-level controller for following these acceleration references and transforming them into actuator commands. The controller is evaluated in a number of challenging scenarios and results in a well behaved vehicle with respect to, e.g., the steering angle, the body slip, and the path. It is also demonstrated that the controller successfully balances braking and avoidance such that it really takes advantage of the braking possibilities. Specifically, for a moving obstacle, it makes use of a widening gap to perform more braking, which is a clear advantage of the online replanning capability if the obstacle should be a moving human or animal. Finally, real-time capabilities are demonstrated. In conclusion, the controller performs well, both from a functional perspective and from a real-time perspective.
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| 7. |
- Hillerström, Gunnar, et al.
(författare)
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Adaptive rejection of periodic disturbances with unknown period
- 1996
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Ingår i: Journal of Dynamic Systems Measurement, and Control. - : ASME International. - 0022-0434 .- 1528-9028. ; 118:3, s. 606-610
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Tidskriftsartikel (refereegranskat)abstract
- A disturbance cancellation extension by means of Youla parametrization to a stabilizing nominal controller is investigated. In the case of known disturbance model, disturbance frequencies or period time, it may be implemented directly as an add-on device to the existing control system. The nominal control system may be designed without consideration of the deterministic disturbances. This way it may suffice with a PID controller. It may also be a more complex one e.g., designed to obtain certain robustness properties. For known relation between the disturbance frequencies (one or more periodic signals) but unknown fundamental frequency, a frequency shaped disturbance model estimarion scheme is utilized. This makes it possible to e.g., adapt the disturbance model to minimize the error directly with respect to the output. For periodic disturbances the scheme implements a self-tuning discrete time repetitive controller. To illustrate the feasibility of the approach taken it is used for rejecting a periodic disturbance acting on a nonminimum-phase plant.
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| 8. |
- Hillerström, Gunnar, et al.
(författare)
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Application of repetitive control to a peristaltic pump
- 1994
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Ingår i: Journal of Dynamic Systems Measurement, and Control. - : ASME International. - 0022-0434 .- 1528-9028. ; 116:4, s. 786-789
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this paper is to study angular velocity control of a rotating axis, a peristaltic pump where the disturbance is associated with certain angular positions. The use of constant sampling rate then implies varying disturbance period. A discrete repetitive control scheme based on a reduced order disturbance model tuned to the setpoint of the angular velocity is shown to reject the modeled disturbance with asymptotically zero error. With axis angle synchronization of sampling, the plant model is time-varying but it gives a static discrete disturbance model independent of the angular velocity. If the deviation from the nominal working point is not too large this is to prefer while it gives faster convergence
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| 9. |
- Holmberg, Ulf, et al.
(författare)
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A Simple Virtual Sensor for Combustion Timing
- 2003
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Ingår i: Journal of Dynamic Systems Measurement, and Control. - New York : American Society of Mechanical Engineers. - 0022-0434 .- 1528-9028. ; 125:3, s. 462-467
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Tidskriftsartikel (refereegranskat)abstract
- Proposes a low-complexity virtual sensor for the pressure peak position of the crank angle in a spark-ignited car motor. Establishment of the relationship between pressure peak position (PPP) and produced work; Introduction of ion-current signal and related to the PPP; Description of previously proposed virtual sensors; Presentation of the low-complexity virtual sensor algorithm; Demonstration of the closed-loop control using the virtual sensor.
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| 10. |
- Ingesson, Gabriel, et al.
(författare)
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Proportional–Integral Controller Design for Combustion-Timing Feedback, from n-Heptane to iso-Octane in Compression-Ignition Engines
- 2017
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Ingår i: Journal of Dynamic Systems, Measurement, and Control, ASME. - : ASME International. - 0022-0434 .- 1528-9028.
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Tidskriftsartikel (refereegranskat)abstract
- The problem of designing robust and noise-insensitive PI controllers for pressure-sensor based combustion-timing control was studied through simulation. Different primary reference fuels (PRF) and operating conditions were studied. The simulations were done using a physics-based, control-oriented model with an empirical ignition-delay correlation. It was found that the controllable region, in-between the zero-gain region for early injection timings and the misfire region for late injection timings is strongly PRF dependent. As a result, it was necessary to adjust intake temperature to compensate for the difference in fuel reactivity prior to the controller design. With adjusted intake temperature, PRF dependent negative-temperature coefficient behavior gave different system characteristics for the different fuels. The PI-controller design was accomplished by solving the optimization problem of maximizing disturbance rejection and tracking performance subject to constraints on robustness and measurement-noise sensitivity. Optimal controller gains were found to be limited by the high system gain at late combustion timings and high-load conditions, furthermore, the measurement-noise sensitivity was found to be higher at the low-load operating points where the ignition delay is more sensitive to variations in load and intake-conditions. The controller-gain restrictions were found to vary for the different PRFs, the optimal gains for higher PRFs were lower due to a higher system gain, whereas the measurement-noise sensitivity was found to be higher for lower PRFs.
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