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Enumeration	Reference	Cover	Find
1.	Andersson, Ingemar, 1969, et al. (author) Detection of Combustion Properties in a Diesel Engine using Block Mounted Accelerometers 2014 In: IFAC Proceedings Volumes (IFAC-PapersOnline). - : Elsevier BV. - 2405-8963 .- 1474-6670. - 9783902823625 ; 19, s. 11866-11871 Conference paper (peer-reviewed)abstract Engine block mounted accelerometers was used for estimating combustion phasing parameters for a heavy duty diesel engine. Several sensor locations were evaluated for its sensitivity to combustion related vibrations and mechanical noise.One sensor-cylinder combination was selected for the evaluation of a simple algorithm to detect 10% and 50% burned mass fraction. The algorithm uses the accumulated accelerometer vibration energy as a base for extracting the 10% and 50% points respectively.The results show that the angular positions for 10% and 50% burned mass fraction can be estimated with precisions of 1.5 and 3 CAD respectively. It is also concluded that the early part of the accelerometer signal has a significant influence from a mechanical noise source related to the start of injection.
2.	Bonafilia, Brian, et al. (author) Robust manual control of a manufacturing system using supervisory control theory 2014 In: IFAC Proceedings Volumes (IFAC-PapersOnline). - : Elsevier BV. - 2405-8963 .- 1474-6670. - 9783902823625 ; 19, s. 748-753 Conference paper (peer-reviewed)abstract There are many situations where manual intervention in automated systems, such as flexible manufacturing systems, is inevitable. Commonly the control of a manufacturing system is implemented in terms of operations, and sequences thereof, and these operations can typically be run manually. However, running the operations in arbitrary order may lead to situations such as blocking or collisions, from which it its hard or even impossible to recover or to resume automatic execution. This paper describes an implementation of an operator interface for robust manual control of a manufacturing system, where the operator is aided not to manually drive the system into a state that breaches the system requirements. Hence, blocking and collisions are avoided, and automatic mode can always be resumed. From a model of the manufacturing system based on self-contained operations, each of which is identified in terms of events with preconditions, a supervisor is calculated by use of the Supervisory Control Theory framework. From this supervisor additional preconditions are extracted for each operation. The operations with the extended preconditions are then ported to an operator interface which allows manual control of the production cell by dynamically guiding the operator to only those operations for which the extended preconditions are satisfied.
3.	Bottegal, Giulio, et al. (author) Analysis and identification of complex stochastic systems admitting a flocking structure 2014 In: IFAC Proceedings Volumes (IFAC-PapersOnline). - : Elsevier BV. - 1474-6670. - 9783902823625 ; , s. 2323-2328 Conference paper (peer-reviewed)abstract We discuss a new modeling paradigm for large dimensional aggregates of stochastic systems by Generalized Factor Analysis (GFA) models. These models describe the data as the sum of a flocking plus an uncorrelated idiosyncratic component. The flocking component describes a sort of collective orderly motion which admits a much simpler mathematical description than the whole ensemble while the idiosyncratic component describes weakly correlated noise. The extraction of the dynamic flocking component is discussed for time-stationary systems.
4.	Dabiri, Azita, 1984, et al. (author) Incident parameter scheduled freeway traffic control - A ramp meter approach 2014 In: IFAC Proceedings Volumes (IFAC-PapersOnline). - : Elsevier BV. - 2405-8963 .- 1474-6670. - 9783902823625 ; 19, s. 11338-11343 Conference paper (peer-reviewed)abstract A novel model based local ramp metering method is presented in the paper by means of incident scheduled freeway traffic control solution. First, second order macroscopic freeway model is used with appropriate incident parametrization to describe eventual and unattended traffic variation caused by off-nominal traffic conditions (e.g. accidents). These traffic anomalies are captured by adequate model parameters, i.e. incident parameters that can be on-line estimated. The paper is motivated by incident scheduled ramp-meter solution to encounter real-time incident parameter information. The main idea is to use local freeway control solution triggered by available incident parameter values. The proposed approach is local in the sense of considering only non-coordinated ramp meter solution, first. Furthermore, we apply locally optimal (linearized) control solution to satisfy throughput maximization objective. The formal controller synthesis involves parameters to correct, compensate the effect of incidents. The proposed method is evaluated and compared to other existing approach by using simulation environment.
5.	Deng, Qichen, et al. (author) A fast algorithm for planning optimal platoon speeds on highway 2014 In: Elsevier IFAC Publications / IFAC Proceedings series. - : IFAC Papers Online. - 1474-6670. - 9783902823625 ; 19, s. 8073-8078 Journal article (peer-reviewed)abstract To meet policy requirements on increased transport energy efficiency and reduced emissions, smart control and management of vehicles and fleets have become important for the development of eco-friendly intelligent transportation systems (ITS). The emergence of new information and communication technologies and their applications, particularly vehicle-to-vehicle and vehicle-to-infrastructure communication, facilitates the implementation of autonomous vehicle concepts, and meanwhile serves as an effective means for control of vehicle fleet by continuously providing support and guidance to drivers. While convoy driving of trucks by longitudinal automation could save 5-15% of fuel consumption due to the reduction of airdrag resistance, this study attempts to investigate the energy saving potential of truck platoons by intelligent speed planning. Assuming that real-time traffic information is available because of communication, an efficient speed control algorithm is proposed based on optimal control theory. The method is faster than the conventional dynamic programming approach and hence applied in the study to analyze energy saving potential of simple platoon operations including acceleration and deceleration. The numerical result shows significant improvement on energy saving due to speed planning during platooning. It can be further applied for more complex platooning operations.
6.	Fridholm, Björn, et al. (author) Robustness comparison of battery state of charge observers for automotive applications 2014 In: IFAC Proceedings Volumes (IFAC-PapersOnline). - : IFAC Secretariat. - 1474-6670. - 9783902823625 ; , s. 2138-2146 Conference paper (peer-reviewed)abstract This paper compares the robustness of three different battery State of Charge (SoC) estimation algorithms: the Extended Kalman Filter (EKF), the Unscented Kalman Filter (UKF) and the H∞ filter. Their performance when subject to disturbances such as parameter uncertainties, different sensor noise characteristics and sensitivity to tuning of the filter are examined. Simulations show that the appropriate choice of observer algorithm will depend on battery chemistry as well as on the intended application. For batteries with a strong correlation between SoC and OCV, the UKF is robust to disturbances such as sensor bias. The H∞ observer shows performance on par with the UKF but the variability of the estimation errors are larger. The EKF is a good all-round choice.
7.	Furberg, Andreas, 1989, et al. (author) Optimal Selection of Driving Modes along a Commuter Route for a Plug-in Hybrid Electric Vehicle 2014 In: IFAC Proceedings Volumes (IFAC-PapersOnline). - : Elsevier BV. - 2405-8963 .- 1474-6670. - 9783902823625 ; , s. 7867-7872 Conference paper (peer-reviewed)abstract Many plug-in hybrid electric vehicles have predefined driving modes, e.g. electric drive and charge sustaining mode. For a driver it is not a trivial task to select a fuel optimal sequence of driving modes; a poor selection might even result in a severely degraded fuel economy. The purpose of this paper is therefore to investigate optimal mode selection along a well known commuter route. To obtain a predictable driving behaviour it is assumed that the driving mode is only allowed to change at a limited number of decision points, located where the driving conditions along the route changes. The optimal mode selection is computed using the well known Dynamic Programming algorithm. However, the results show that the optimal mode selection might be perceived as counterintuitive, as a mode is not necessarily optimal over a connected set with respect to battery state of charge, at a given decision point. To mitigate this type of behaviour a suboptimal algorithm is proposed, in which a mode is associated with one unique interval of state of charge at any decision point along the route. The results indicate that the proposed algorithm is only marginally suboptimal with respect to the optimal solution.
8.	Georgiou, T. T., et al. (author) On time-reversibility of linear stochastic models 2014 In: IFAC Proceedings Volumes (IFAC-PapersOnline). - : IFAC Papers Online. - 1474-6670. - 9783902823625 ; , s. 10403-10408 Conference paper (peer-reviewed)abstract Reversal of the time direction in stochastic systems driven by white noise has been of central importance throughout the development of stochastic realization theory, filtering and smoothing. Similarly, in connection with certain problems in the theory of moments, the duality induced by time reversal was the key to deriving a compact parametrization and an interpretation of solutions. By combining ideas from these two lines of development we present herein a general view and a simplified account of time-reversal in stochastic models.
9.	Grahn, Markus, 1978, et al. (author) A Transient Diesel EMS Strategy for Online Implementation 2014 In: IFAC Proceedings Volumes (IFAC-PapersOnline). - : Elsevier BV. - 2405-8963 .- 1474-6670. - 9783902823625 ; 19, s. 11842-11847 Conference paper (peer-reviewed)abstract A recently developed strategy for diesel engine management systems is modified to reduce the implementation complexity. The strategy calculates set points for engine management system controllable quantities with an aim to minimize fuel consumption for a given engine speed and requested torque profile, while keeping accumulated emissions below given limits. The strategy is based on the methodology for steady-state engine operation, but extended to handle transient effects in the engine caused by dynamics in the air system. The strategy leads to the parametrization of mappings with two, three and four input dimensions respectively. In this paper, a modification of the strategy is proposed such that the memory demanding multidimensional mappings can be approximated in an engine management system using only two-dimensional grid maps. The modified strategy has been evaluated using a complete diesel engine vehicle system model simulating the NEDC driving cycle. The performance of the modified strategy has been compared with the original performance of the strategy. It is demonstrated that the modification of the strategy has very little impact on resulting performance of a vehicle but requires considerably less memory for implementation.
10.	Hanebeck, U. D., et al. (author) Moment-based dirac mixture approximation of circular densities 2014 In: IFAC Proceedings Volumes (IFAC-PapersOnline). - : Elsevier BV. - 1474-6670. - 9783902823625 ; , s. 5040-5048 Conference paper (peer-reviewed)abstract Given a circular probability density function, called the true probability density function, the goal is to find a Dirac mixture approximation based on some circular moments of the true density. When keeping the locations of the Dirac points fixed, but almost arbitrarily located, we are applying recent results on the circulant rational covariance extension problem to the problem of calculating the weights. For the case of simultaneously calculating optimal locations, additional constraints have to be deduced from the given density. For that purpose, a distance measure for the deviation of the Dirac mixture approximation from the true density is derived, which then is minimized while considering the moment conditions as constraints. The method is based on progressive numerical minimization, converges quickly and gives well-distributed Dirac mixtures that fulfill the constraints, i.e., have the desired circular moments.
11.	Johnsson, Charlotta, et al. (author) Fostering Automatic Control Students to Become Innovators 2014 In: Proceedings of the 19th IFAC World Congress, 2014. - 1474-6670. - 9783902823625 ; , s. 12255-12260 Conference paper (peer-reviewed)abstract Today, innovation is a key word for many universities, as it constitutes an important part of most universities’ public and scientific outreach task. Many universities are striving to increase the number of innovations generated at the university. A common method is to provide various support for research projects e.g.; providing researchers with information about international patent rights (IPR), offering administrative or financial help concerning patent applications, giving entrepreneurship and start-up support, etc. However, fostering innovators and entrepreneurs can start already in undergraduate/graduate courses, i.e. long before a student potentially reaches the research level. We believe that key factors for success in this matter are diversity and freedom. A course that strives to promote innovation capability must allow for students with different backgrounds and different curricula to meet and work together, and must allow for students to freely use their current knowledge within new contexts. This is generally not a setting provided in traditional undergraduate/graduate courses. This article describes the execution and outcome of an graduate course “international Market-Driven Engineering (iMDE)” in which diversity and freedom are key factors. The course is international and multi-disciplinary in terms of students, teachers and subjects. Graduate students with prior knowledge in automatic control constitute one important part of the course population. We believe that the diversity amongst the students, and their freedom when it comes to both innovation process and product, provides a promising platform in which seeds of ideas can grow into conceptual prototypes that build a solid foundation for full-scale innovations. On of the iMDE- projects, the Elderly Accessible Chair, or EA Chair, with its automated scanning and automatic seat- provider functionality, is one concrete example of this.
12.	Kianfar, Roozbeh, 1984, et al. (author) A Control Matching-based Predictive Approach to String Stable Vehicle Platooning 2014 In: IFAC Proceedings Volumes (IFAC-PapersOnline). - : Elsevier BV. - 2405-8963 .- 1474-6670. - 9783902823625 ; 19, s. 10700-10705 Conference paper (peer-reviewed)abstract A predictive control strategy for vehicle platoons is presented in this paper,accommodating both string stability and constraints (e.g., physical and safety) satisfaction.In the proposed design procedure, the two objectives are achieved by matching a ModelPredictive Controller (MPC), enforcing constraints satisfaction, with a linear controller designedto guarantee string stability. The proposed approach neatly combines the straightforward designof a string stable controller in the frequency domain, where a considerable number of approacheshave been proposed in literature, with the capability of a MPC-based controller of enforcingstate and input constraints.A controller obtained with the proposed design procedure is validated in simulations, showinghow string stability and constraints satisfaction can be simultaneously achieved with a singlecontroller. The operating region that the MPC controller is string stable is characterized by theinterior of feasible set of the MPC controller.
13.	Lei, Z., et al. (author) Residual capacity estimation for ultracapacitors in electric vehicles using artificial neural network 2014 In: IFAC Proceedings Volumes (IFAC-PapersOnline). - : Elsevier BV. - 2405-8963 .- 1474-6670. - 9783902823625 ; 19, s. 3899-3904 Conference paper (peer-reviewed)abstract The energy storage system (ESS) plays a significant role in fulfilling the driving performance requirements and ensuring operational safety in an electric vehicle. Ultracapacitors (UCs) are being actively studied and used in parallel with batteries or fuel cells forming hybrid energy storage systems in electric vehicles. They show excellent potential in terms of the sourcing and sinking of power, particularly for the peak-power demand encountered in aggressive regenerative braking. Since there are an increasing number of ultracapacitor applications, which now includes commercial automotive applications, establishing a good model to represent their dynamics, especially the residual capacity estimation (RCE), is vital; but this is challenging. This paper presents a residual capacity estimation model which is based on an artificial neural network (ANN). This takes both charging and discharging current and temperature into consideration. The proposed ANN model comprises of three inputs and one output: the inputs are temperature, current and voltage, and the output is the residual charge. The model is trained and validated by feeding a test database which is extracted from experimental testing of ultracapacitors at different currents and temperatures on a well-established test rig. The training data should span the whole prediction scope, therefore the test currents and temperatures both vary over a wide range and cover all the possible operational conditions of the on-board ultracapacitors. The Back-Propagation (BP) algorithm, together with an early stopping strategy, is adopted to train the proposed ANN model to assure adequately accurate prediction while avoiding overfitting risks. The model performance is validated with experimental results over a set of test data randomly selected.
14.	Leong, A. S., et al. (author) Network topology reconfiguration for state estimation over sensor networks with correlated packet drops 2014 In: IFAC Proceedings Volumes (IFAC-PapersOnline). - : IFAC Papers Online. - 1474-6670. - 9783902823625 ; , s. 5532-5537 Conference paper (peer-reviewed)abstract This paper studies the problem of optimal network topology reconfiguration in sensor networks for state estimation. Multiple sensors make observations of a process, which are then transmitted, possibly via intermediate sensors, to a central gateway. Transmission over each link can experience packet drops. The time-varying wireless network environment is modelled by the notion of a network state as in Quevedo et al. (2013a). For each network state, different network configurations can be used, which govern the network topology and routing of packets. Switching between different configurations incurs a cost, in that unwanted links will need to be removed before the establishment of new links, leading to a transient time in which some links may not be available. The problem is to determine the optimal network configurations to use in each network state, in order to minimize an expected error covariance measure that takes into account the cost of reconfiguration. A simpler suboptimal method which minimizes the upper bound of the expected error is also proposed, which in numerical simulations gives essentially identical results to the optimal method.
15.	Liu, Z., et al. (author) Synchronization of unicycle robots with proximity communication networks 2014 In: IFAC Proceedings Volumes (IFAC-PapersOnline). - : IFAC Papers Online. - 1474-6670. - 9783902823625 ; , s. 9197-9202 Conference paper (peer-reviewed)abstract In this paper synchronization of both the orientation and velocity for a group of unicycle robots is studied. It is assumed that a robot can only detect and obtain information from those robots that lie in the proximity (within certain distance). A minimum dwell time is imposed on the updating of neighborhood relation in the controller in order to avoid introducing chattering in the closed-loop system that may be caused by abrupt changes of the relation, which as a consequence implies that the neighbor information will be updated only at discrete time instants in the control. In the paper a distributed feedback control law is designed for each agent, and a sufficient condition for uniformly and independently distributed initial states is provided for reaching the synchronization, which depends on the neighborhood radius, the maximum initial translational velocity and the dwell time.
16.	Lucchese, Riccardo, et al. (author) Distributed detection of topological changes in communication networks 2014 In: 19th IFAC World Congress on International Federation of Automatic Control. - : IFAC Papers Online. - 9783902823625 ; , s. 1928-1934, s. 1928-1934 Conference paper (peer-reviewed)abstract Changes in the topology of communication networks, such as sudden appearance or disappearance of links or nodes, may signal malicious attacks or malfunctions. A topology change detector may thus be useful to trigger alarms or self-reconfiguration procedures. Here we present a novel approach that enjoys several desirable qualities such as fast convergence, intrinsically distributed computations, and scalability w.r.t. communication and computational requirements. We characterize the performance of this technique from analytical and practical points of view, providing theoretical results on its performance. We thus show how it is possible to tune and trade-off the accuracy of the change detection results with the communication requirements of the procedure.
17.	Murgovski, Nikolce, 1980, et al. (author) Computationally efficient energy management of a planetary gear hybrid electric vehicle 2014 In: IFAC Proceedings Volumes (IFAC-PapersOnline). - : Elsevier BV. - 2405-8963 .- 1474-6670. - 9783902823625 ; 19 Conference paper (peer-reviewed)abstract We present a method for obtaining a computationally efficient, sub-optimal energy management of an electrified vehicle containing a planetary gear set. We first reformulate the optimization problem to become separable in space (optimization variables). The problem is then decomposed into two optimization problems. The first is a static problem that looks for the optimal engine speed that maximizes efficiency of a compound unit, resembling an engine-generator unit combining the planetary gear and kinetic energy converters connected to it. The second is a dynamic optimization problem deciding the optimal power split between an electric buffer and the compound unit. By approximating the losses of the compound unit as convex, second order polynomial in generated power, we are able to solve the power split problem in less than 2 seconds, when the engine on/off sequence is known in advance. By comparing results with dynamic programming, we observed an approximation error of less than 0.2%.
18.	Nilsson, Julia, 1986, et al. (author) Manoeuvre generation and control for automated highway driving 2014 In: IFAC Proceedings Volumes (IFAC-PapersOnline). - : Elsevier BV. - 2405-8963 .- 1474-6670. - 9783902823625 ; 19, s. 6301-6306 Conference paper (peer-reviewed)abstract A hierarchical, two-level architecture for manoeuvre generation and vehicle control for automated highway driving is presented. The high-level planner computes a manoeuvre in terms of a (X, Y)-trajectory as well as a longitudinal velocity profile, utilizing a simplified point-mass model and linear collision avoidance constraints. The low-level controller utilizes a non-linear vehicle model in order to compute the vehicle control inputs required to execute the planned manoeuvre. Both the high-level planner and low-level controller are formulated based on the model predictive control methodology. Simulation results demonstrates the ability of the high-level planner to compute appropriate, traffic-dependent manoeuvres, that can be tracked by the low-level controller in real-time.
19.	Nilsson, Jonas, 1979, et al. (author) Verification of Collision Avoidance Systems using Reachability Analysis 2014 In: IFAC Proceedings Volumes (IFAC-PapersOnline). - : Elsevier BV. - 2405-8963 .- 1474-6670. - 9783902823625 ; 19, s. 10676-10681 Conference paper (peer-reviewed)abstract This paper presents a method for formal verification of automotive collision avoidance systems. Using viability theory and reachability analysis, we define when the system should intervene, i.e. the unsafe set, and when the system should not intervene, i.e. the safe set. Given these sets, we formulate the problem of verifying that a given system does not make incorrect decisions as an optimization problem. The method is demonstrated on a collision avoidance system example and, given the models used and absence of measurements errors, we show that the system does not make incorrect decisions. Furthermore, we describe and demonstrate how to evaluate the robustness to measurement errors, using the proposed framework.
20.	Pourabdollah, Mitra, 1984, et al. (author) An iterative dynamic programming/convex optimization procedure for optimal sizing and energy management of PHEVs 2014 In: IFAC Proceedings Volumes (IFAC-PapersOnline). - : Elsevier BV. - 2405-8963 .- 1474-6670. - 9783902823625 ; 19, s. 6606-6611 Conference paper (peer-reviewed)abstract This paper proposes a time-efficient method for sub-optimal design of a plug-in hybrid electric vehicle with a parallel powertrain topology. The method finds the optimal design of the vehicle by iteratively using dynamic programming (DP) and convex optimization to minimize sum of operational and component costs over a given driving cycle. In particular, DP is used to optimize energy management, gear shifting and engine on-off for given component sizes, and convex optimization is used to optimize energy management and component sizes using the gear shifting and engine on-off strategies obtained by DP. Next, DP is re-optimized with the component sizes obtained by convex optimization, and the procedure is repeated until the component sizes converge. The result of this iterative method is compared by using DP on a grid of possible component sizes. It is shown that the iterative method gives a result very close to the global optimum in a comparably short time.
21.	Shoaei, Mohammad Reza, 1983, et al. (author) On the Computation of Natural Observers for Extended Finite Automata 2014 In: IFAC Proceedings Volumes (IFAC-PapersOnline). - : Elsevier BV. - 2405-8963 .- 1474-6670. - 9783902823625 ; 19, s. 2448-2455 Conference paper (peer-reviewed)abstract Compared to finite automata, Extended Finite Automata (EFAs) allows us to efficiently represent discrete-event systems that involve non-trivial data manipulation. However, the complexity of designing supervisors for such systems is still a challenge. In our previous works, we have studied model abstraction for EFAs using natural projections with observer property on events as well as data. In this paper, we provide sufficient conditions for verifying the observer properties and further enhance the EFAs when the property does not hold. To this end, we introduce symbolic simplification techniques for data and generalize existing algorithms in the literature for the events to compute natural observers for EFAs. The importance of this combined abstraction and symbolic simplification method is demonstrated by synthesis of a nonblocking controller for an industrial manufacturing system.
22.	Song, Yujiao, 1986, et al. (author) Nyquist stability analysis of a VSC-HVDC system using a distributed parameter DC-cable model 2014 In: IFAC Proceedings Volumes (IFAC-PapersOnline). - : Elsevier BV. - 2405-8963 .- 1474-6670. - 9783902823625 ; 19, s. 8202-8209 Conference paper (peer-reviewed)abstract In this paper a two terminal VSC-HVDC system embedded in a strong grid ACenvironmentis considered, emphasizing modeling, controllers design and small-signal stabilityanalysis. Traditionally, DC cables are most often modeled by Π-sections, and when using themfor higher frequencies or in case of transmission over long distances, approximation accuracyaspects must be considered. Here, a distributed parameter cable model, based on the dampedwave equation, is used to overcome this limitation. It is shown that the VSC-HVDC system canbe described by a forward transfer function cascaded with a feedback loop. The first transferfunction will be different, due to which input and output variables that are considered but is inall realistic cases stable. The feedback loop, where the forward path is a rational function andthe return path is a dissipative infinite dimensional system, remains the same in all cases. Thestability is then analyzed, using the Nyquist criterion, in a straight forward manner. Numericalexamples are given by MATLAB.
23.	Stotsky, Alexander, 1960 (author) Wind turbine model validation: Fusion of simulation and measurement data 2014 In: IFAC Proceedings Volumes (IFAC-PapersOnline). - : Elsevier BV. - 2405-8963 .- 1474-6670. - 9783902823625 ; 19, s. 3629-3632 Conference paper (peer-reviewed)abstract A new turbine model validation technique that is based on adaptation of look-up tables is described this paper. Simulation results from the VIDYN turbine simulation program and measurements from Big Glenn wind turbine, located outside Gothenburg, Sweden are used as an input to this new model validation technique. The models of the flapwise bending moment and power coefficient are validated for Big Glenn turbine. Measurement data are acquired during normal turbine operation. Verification results show good agreement between model outputs and measured data. The method allows prediction in a wide range of turbine operating variables, using only few measured points.
24.	Tayamon, soma, 1984, et al. (author) Modelling of selective catalytic reduction systems using discrete-time Linear Parameter Varying models 2014 In: IFAC Proceedings Volumes (IFAC-PapersOnline). - : Elsevier BV. - 2405-8963 .- 1474-6670. - 9783902823625 ; 19, s. 5685-5690 Conference paper (peer-reviewed)abstract In this work, a Linear Parameter Varying (LPV) model of the Selective CatalyticReduction (SCR) system, used for NOxreduction placed as after-treatment systems in dieselengines is developed. The LPV model structure is formed utilising the physical properties of thesystem yielding only 7 unknown parameters for a third order model structure of the SCR, whichis a significant reduction in number of parameters in comparison with other nonlinear modelsused in this paper. The states of the model however, do not possess any physical interpretation.The LPV model structure is validated using real measured data from cell tests at Scania ABwith promising results. The proposed model is compared to previous global nonlinear models ofthe system, i.e. a nonlinear state space model and a Hammerstein-Wiener model of the system.
25.	Zanon, M., et al. (author) Airborne wind energy: Airfoil-airmass interaction 2014 In: IFAC Proceedings Volumes (IFAC-PapersOnline). - : Elsevier BV. - 2405-8963 .- 1474-6670. - 9783902823625 ; 19, s. 5814-5819 Conference paper (peer-reviewed)abstract The Airborne Wind Energy paradigm proposes to generate energy by flying a tethered airfoil across the wind flow at a high velocity. While Airborne Wind Energy enables flight in higher-altitude, stronger wind layers, the extra drag generated by the tether motion imposes a significant limit to the overall system efficiency. To address this issue, two airfoils with a shared tether can reduce overall system drag. A study proposed in Zanon et al. (2013) confirms this claim by showing that, in the considered scenario, the dual-airfoil system is more advantageous than the single-airfoil one. The results computed in Zanon et al. (2013) however, do not model the interaction between the airfoils and the airmass. In this paper, the impact of the airfoil-airmass interaction on the extracted power is studied. As this phenomenon is complex to model, a blade element-momentum approach is proposed and the problem is solved by means of optimal control techniques.
26.	Hang, Chang C., et al. (author) Practical Aspects of PID Auto-Tuners Based on Relay Feedback 1988 In: 2nd International IFAC Symposium on Adaptive Control of Chemical Processes 1988 (ADCHEM '88), Lyngby, Copenhagen, Denmark, 17-19 August. - 1474-6670. ; 21:7, s. 153-158 Conference paper (peer-reviewed)
27.	Johansson, Rolf (author) Lyapunov Design for Adaptive Control of Robots 1989 In: IFAC Proceedings Volumes (IFAC-PapersOnline). - 1474-6670. ; 22:3 Journal article (peer-reviewed)abstract This paper presents algorithms for continuous-time direct adaptive control of robot manipulators. Lyapunov theory is used for controller design and stability investigation. Algorithms for rapid continuous-time adaptive control are presented.
28.	Källström, Claes, et al. (author) Adaptive Autopilots for Large Tankers 1978 In: 7th Triennial World Congress of the IFAC : A Link Between Science and Applications of Automatic Control, Helsinki, Finland, 12-16 June - A Link Between Science and Applications of Automatic Control, Helsinki, Finland, 12-16 June. - 1474-6670. ; 11:1, s. 477-484 Conference paper (peer-reviewed)abstract The adaptive autopilots are based on velocity scheduling, a self-tuning regulator for steady state course keeping, a high gain turning regulator with variable structure, and a Kalman filter. Results from simulations and full-scale experiments on three different tankers are presented. The autopilots are shown to work excellently under different loads, speed and weather conditions.
29.	Olsson, Gustaf, et al. (author) Estimation and Control of Biological Activity in the Activated Sludge Process Using Dissolved Oxygen Measurements 1977 In: IFAC Symposium on Environmental Systems Planning, Design and Control, Kyoto, Japan, 1-5 August. - 1474-6670. ; 10:7, s. 745-755 Conference paper (peer-reviewed)abstract The control of an activated sludge process is considered. It is discussed how the organism activity is a crucial information for the control. It is shown, how the concentration profile of dissolved oxygen (DO) in the biological reactor is related to the sludge activity. As a result the DO profile is a useful measurement information for control purposes
30.	Åström, Karl Johan, et al. (author) Analysis of a Scheme for Iterated Identification and Control 1994 In: IFAC Symposium on System Identification (SYSID'94), Copenhagen, Denmark, 4-6 July. - 1474-6670. ; 27:8, s. 473-478 Conference paper (peer-reviewed)abstract This paper presents analysis of a scheme for iterated identification and control design. The approach is based on least squares identification in closed loop and pole placement design. It has previously been shown that the criteria for control and identification are the same provided that the data filters are chosen properly. The iterated scheme may be viewed as a recursion in model parameters. Each step consists of system identification and control design. Interesting questions are then: What are the fix points? Are the fix points stable? These questions are investigated for some simple examples. Relations to other problems like model reduction and adaptive control are also discussed.
31.	Birk, Wolfgang, et al. (author) Foam level control in a water model of the LD converter process 2001 In: Automation in mining, mineral, and metal processing 2001. - Oxford : Published for the International Federation of Automatic Control by Pergamon. - 1474-6670. - 0080436927 Conference paper (peer-reviewed)abstract This paper deals with estimation and control of foam level in dynamic foaming. An improved foam level estimation methodology from a microphone signal and its automatic calibration is presented. The dynamical reaction of the foam level on air lance movements is modelled using system identification. Based on the resulting mathematical model, a controller for foam level stabilisation is designed and applied to a water model, representing the LD converter process. It is shown that the foam level can be controlled using a microphone as the measurement device and air lance movement as the actuator.
32.	Ding, Limei, et al. (author) Application of fuzzy control to a flotation process 1999 In: Elsevier IFAC Publications / IFAC Proceedings series. - Kildington : Elsevier. - 1474-6670. ; 32:2, s. 6998-7003, s. 391-396 Journal article (peer-reviewed)abstract The application of fuzzy logic in the control of flotation is studied in this paper. A general description of apatite flotation process is given and a dynamic model is developed. A fuzzy logic controller is proposed for a nonlinear isolated continuous flotation process. The knowledge base of the controller is constructed on the basis of the semi-batch results from the apatite flotation experiments and available knowledge sources. The design of the controller does not need an exact process model. The simulation result shows that the fuzzy logic controller can reduce collector dosage consumption of the apatite flotation process while maintaining the phosphorous content in magnetite concentrate within an acceptable limits less than 0.025% P. Stability of the fuzzy control system is discussed
33.	Fischer, Britta, et al. (author) Control Relevant Identification in H∞ - Adaptive Information and Experiment Design 1996 In: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. - 0080429084 ; 29:1, s. 4046-4051 Journal article (peer-reviewed)abstract Joint issues of modelling and control design are studied in a frequency domain setup. Stable systems with monotone Bode plots are chosen as the basis of the study presented in this work. Such dynamics is typical for plants in industrial process control. Adaptive information is considered and both open-loop and closed-loop experimental conditions are included. For systems with monotone Bode plots the information typically required for successful control design consists of a small part of the frequency response only. This can be exploited in experiment design.
34.	Fischer, Britta, et al. (author) Laguerre domain estimation of time delays in narrowband ultrasonic echoes 1999 In: Proceedings of the 14th World Congress. - Kildington : Publ. for the International Federation of Automatic Control by Pergamon. - 1474-6670. - 0080432190 ; , s. 361-366 Conference paper (peer-reviewed)abstract The time delay of arrival (TDOA) is required in many areas in signal processing. In this paper we propose a novel and straightforward method to estimate small continuous time delays in narrowband signals out of a sampled sequence of the input and output signals. It is based on the parameterization of the identification problem in the Laguerre functions. An lp norm optimal estimator is then applied to estimate the delay. Furthermore, estimation bounds are studied and experiments from ultrasonic applications are presented to highlight the performance of the method
35.	Forsberg, Johan, et al. (author) An autonomous plastering robot for walls and ceilings 1995 In: Elsevier IFAC Publications / IFAC Proceedings series. - Oxford : Pergamon Press. - 1474-6670. - 0080423663 ; 28:11, s. 301-306 Journal article (peer-reviewed)abstract This paper presents a robot and algorithms for autonomous spray plastering of walls and ceilings during the construction of apartment houses. Successful experimental tests are described where the robot measures the size of the room and the location of doors and windows. The work sequence is then planned and executed autonomously. To sense the environment the robot uses a range measuring scanning laser. The range weighted Hough transform is used to observe the walls and the resulting observations are used to update estimates in an extended Kalman filter based map. Association of observations to estimates is performed using the estimated probability of a correct match, taking correlations between estimates into account when needed.
36.	Hillerström, Gunnar, et al. (author) Repetitive control theory and applications : a survey 1996 In: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. - 0080429084 ; 29:1, s. 1446-1451 Journal article (peer-reviewed)abstract The aim of this paper is to present repetitive control, controllers for rejecting periodic disturbances or tracking periodic reference signals, This survey covers both continuous and discrete time theory, together with a number of applications
37.	Högström, Tomas, et al. (author) On Segmentation, Shape Estimation and Navigation Using 3D Laser Range Measurements of Forest Scenes 1998 In: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. - 0080429297 ; 31:3, s. 423-428 Journal article (peer-reviewed)abstract The problem addressed is segmentation and shape estimation of three-dimensional laser range measurements of forest scenes. For each tree the position as well as the three dimensional shape of the trunk is estimated. The detection uses a two-dimensional histogram of the measurements, followed by segmentation by fitting cylinders around the measurements of each detected tree trunk. The shape estimation consists of fitting a 3D spline to each tree trunk's centre curve and computing the trunk width by extracting the range discontinuities at the edges. For the experiments a mobile robot carrying a scanning laser range finder was used. Navigation was done by matching the extracted tree trunk positions from subsequent range scans, determining the relative movements
38.	Högström, Tomas, et al. (author) Telecommands for Remotely Operated Vehicles 1995 In: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. - 0080423663 ; 28:11, s. 301-306 Journal article (peer-reviewed)abstract The problem addressed is controlling a robot over a communication channel with low bandwidth, a non-neglectable time delay and time jitters. The external sensors on the robot are a time-of-flight range measuring laser and a video camera. Video images are used by the operator for interpreting the scene and are only sent at “fax rate”. The operator is thus interpreting the workspace around the vehicle, making plans for the individual operations in a composite task and is giving high level commands. The telecommands are to be executed autonomously by the robot. Inside the robot the control loop is closed with full bandwidth when each command is executed.This paper reports on work in progress and focus on:1. Incremental map building, especially simplifications for large buildings and robustness when the vehicle returns to a previously mapped area. This is a very useful support function for the operator.2. Tests of telecommands on a mobile robot available for experiments over the Internet. Available sensors are inclinometers, odometry, CCD intensity images and range measuring laser data.Other needed telecommands studied previously are:Travelling along corridors, follow walls etc. The operation is based on the range weighted Hough transform and is both robust and precise. The repeatability is about 1 cm at 1 m/s. The robot is not disturbed by people passing in the corridor.Commands for passage through an open door works within 1 cm and 0.5 degrees at a speed of 0.5 m/s. Passing between irregular obstacles is less accurate.Using rate gyros, lock the heading of the robot when driving on a straight line. Also preprogrammed 90- and 180-degrees turns.Automatically enter a camera defined line. The direction of the camera can be used to drop a new coordinate frame at any time (using a button on the keyboard). The robot will automatically enter this new line and also compensate for the overshoot.To integrate these different commands into a complete system is a resource demanding task for the future.
39.	Johansson, Andreas, et al. (author) Nonlinear observer for estimation of metal analysis in steel converters 2001 In: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. - 0080435602 ; 34:6, s. 1325-1330 Journal article (peer-reviewed)abstract A nonlinear observer whose feedback is weighted by the sensitivity of the output with respect to the state is considered. Conditions for asymptotic stability as well as a region of attraction of the estimation error equation are derived. The results are applied to the problem of metal analysis estimation in a steel converter process
40.	Larsson, Ulf, et al. (author) On rate gyros for improved navigation by reducing dead-reckoning errors 1998 In: Elsevier IFAC Publications / IFAC Proceedings series. - Oxford : Pergamon Press. - 1474-6670. ; 31:3, s. 207-212, s. 207-212 Journal article (peer-reviewed)abstract Consider a vehicle using a number of landmarks for navigation. Between the observation of the landmarks, the motion of the vehicle is estimated using internal sensors like odometers and rate gyros. The output from a dead reckoning algorithm is used in a Kalman filter and/or used to make association of observed landmarks. In such a system the accuracy of the dead reckoning algorithm is essential for the overall performance. In the paper `slip angles' at the wheel-surface contact point are included in the kinematic model. The slip angle is assumed to be essentially proportional to the side force. The topics considered in the paper are: dead reckoning model with a slip angle; improved dead reckoning when a rate gyro is used; and equations for comparing the error growth. Four different algorithms for dead reckoning are studied and compared. Two of them just model the slippage and two of them are based on more accurate measurements of rotation, using a rate gyro
41.	Madala, Hemarao (author) GMDH as an identification and modelling tool for biotechnical processes 1983 In: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. - 0080299784 ; 16:14, s. 225-229 Journal article (peer-reviewed)abstract This paper describes GMDH as an identification and modelling tool for biotechnical processes. Several examples are considered by using a known simulated data. The identified models could be used further in analysing the processes by using online algorithms.
42.	Madala, Hermano (author) Self-Organization GMDH Computer Aided Design for Modelling of Cyclic Processes 1983 In: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. ; 16:19, s. 611-618 Journal article (peer-reviewed)abstract The Group Method Data Handling (GMDH) is a specific selforganization computer-aided design which has been proposed by Ivakhnenko (1970, 1971) and which has been described in several recent articles (Ivakhnenko et al, 1978, 1979a) and also in Soviet Automatic Control (USA). One of the several interesting properties of this CAD is its apparent ability to make high accuracy predictions of future states of complex systems. The development presents a procedure for constructing models in a simple and systematic way for complex systems which are cyclic in nature. In the present paper the structures of finite-difference models for cyclic processes are described. The criterion of prediction balance is used for analysing the optimal model. System of combined models constructed in this manner is used recursively for predicting the future states of the cyclic system. Three examples are given. One example used the data generated from a known model and the others the airtemperature data with large number of points and the tea-crop production data with less number of points. The system of combined models is compared with the single overall model. The former has given reasonably better results. The models are checked for stability in long-range actions.
43.	Madala, Hemarao, et al. (author) Some Experimental Results of Digital Signal Processing 1983 In: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. ; 16:15, s. 531-535 Journal article (peer-reviewed)abstract This paper describes some of the experimental results in processing of signals in finding out the length of a tube. The paper is divided into two parts consisting of different results. The aim of the first part is to find out the behaviour of A parameters of AR model and how they change as the length of the tube varies and to discover a single model of length as a function of A parameters treating the system as a black box. Linear Moving Averages (LMA) used in this paper eased the situation in filtering out the disturbances on A parameters and in getting the exact model. Optimal length of LMA is found out for the given situation. This type of model is useful in the continuous case. In the second part a new harmonical algorithm is described for identifying the signals from the experiment. The estimated models show reasonably good results. The results are discussed for different lengths of the tube.
44.	Medvedev, Alexander (author) Disturbance attenuation in finite spectrum assignment controllers 1996 In: Elsevier IFAC Publications / IFAC Proceedings series. - : Elsevier. - 1474-6670. ; 29:1, s. 1620-1625 Journal article (peer-reviewed)abstract Two finite-spectrum-assignment controllers for continuous linear dynamic systems with multiple time delays in input signal are introduced. The controllers are shown to comprise least-squares state estimators. Disturbance attenuation properties stipulated by the choice of shift operator in the observers are studied.
45.	Medvedev, Alexander, et al. (author) External model control of a peristaltic pump 1994 In: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. - 0080422292 ; 27:2, s. 519-524 Journal article (peer-reviewed)abstract An observer-based approach to perfect disturbance rejection in linear continuous systems with delayed control is presented and exemplified by an application to a peristaltic pump. Disturbance rejection properties of the Smith Predictor are studied. A recently developed technique of continuous deadbeat observation is exploited to predict the disturbance signal which is described by a known dynamic model. It is shown that under certain algebraic conditions a disturbance estimate based control law is able to provide a disturbance-free output signal. The disturbance rejection scheme can be used in combination with any conventional control technique such as stabilizing or servo controller.
46.	Medvedev, Alexander (author) Fault Detection by Continuous Dead-Beat Observation 1994 In: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. - 0080422225 ; 27:5, s. 28-33 Journal article (peer-reviewed)abstract An application of continuous-time deadbeat observation to fault analysis in linear dynamic systems is discussed. A finite memory residual chosen as a difference of two deadbeat state vector estimates is shown to be independent of both the state vector and control signal. The mapping of the fault mode to the residual is proven to be intrinsically BIBO-stable. Exploiting a decomposition of the “sliding-window” convolution operator, an upper bound for residual norm is derived and a fault detectability condition is obtained. Due to its simple structure, the deadbeat observer does not create a hard computational burden and can be easily implemented in real-time applications.
47.	Medvedev, Alexander (author) State estimation and fault detection by a bank of continuous finite-memory filters 1996 In: Elsevier IFAC Publications / IFAC Proceedings series. - : Elsevier. - 1474-6670. ; 29:1, s. 6542-6547 Journal article (peer-reviewed)abstract A continuous observer estimating the state vector of a linear time-invariant system from the measurements of the system's inputs and outputs passed through a bank of finite-memory filters is introduced. System observability is shown to guarantee the existence of the observer. An application of the observer to the problem of detecting and isolating sensor and actuator faults is discussed
48.	Mäkilä, Pertti, et al. (author) Robust identification 1994 In: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. ; 27:8, s. 45-63 Journal article (peer-reviewed)abstract This paper introduces the reader to several recent developments in robust identification motivated by various issues of modelling of systems from data for the purpose of robust control design. Many aspects of identification in H∞ and l1 are covered; including algorithms, convergence and divergence results, control relevancy issues, and objective worst case estimation of uncertainty models
49.	Nilsson, Bernt, et al. (author) On Control of Flexible Mobile Manipulators: Positioning and Vibration Reduction Using an Eye-in-Hand Range Camera 1998 In: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. ; 31:3, s. 619-625 Journal article (peer-reviewed)
50.	Rönnbäck, Stefan, et al. (author) A design algorithm for anti-windup compensators : polynomial approach 1993 In: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. - 008042211X ; 26:2:5, s. 619-624 Journal article (peer-reviewed)abstract It is discussed how an LTI ‘polynomial controller’ for a SISO-system with actuator constraints can be designed using conventional linear pole-placement technique. This becomes possible due to the utilization of an ‘anti-windup’ technique in which the effect of control-signal saturation is interpreted as being caused by an equivalent disturbance. The results are summarized into a ‘design algorithm’ which supports a complete separation of 'servo', ‘disturbance-rejection’ and ‘anti-windup’ poles. It also supports the introduction of arbitrary 'specific factors’ into the controller polynomials, and it can be used for both continuous-time and discrete-time controllersIt is discussed how an LTI ‘polynomial controller’ for a SISO-system with actuator constraints can be designed using conventional linear pole-placement technique. This becomes possible due to the utilization of an ‘anti-windup’ technique in which the effect of control-signal saturation is interpreted as being caused by an equivalent disturbance. The results are summarized into a ‘design algorithm’ which supports a complete separation of 'servo', ‘disturbance-rejection’ and ‘anti-windup’ poles. It also supports the introduction of arbitrary 'specific factors’ into the controller polynomials, and it can be used for both continuous-time and discrete-time controllers.

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