| 1. |
- Frisk, Erik, et al.
(författare)
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Analysis and Design of Diagnosis Systems Based on the Structural Differential Index
- 2017
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Ingår i: 20th IFAC World Congress. - : ELSEVIER SCIENCE BV. ; , s. 12236-12242
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Konferensbidrag (refereegranskat)abstract
- Structural approaches have shown to be useful for analyzing and designing diagnosis systems for industrial systems. In simulation and estimation literature, related theories about differential index have been developed and, also there, structural methods have been successfully applied for simulating large-scale differential algebraic models. A main contribution of this paper is to connect those theories and thus making the tools from simulation and estimation literature available for model based diagnosis design. A key step in the unification is an extension of the notion of differential index of exactly determined systems of equations to overdetermined systems of equations. A second main contribution is how differential-index can be used in diagnosability analysis and also in the design stage where an exponentially sized search space is significantly reduced. This allows focusing on residual generators where basic design techniques, such as standard state-observation techniques and sequential residual generation are directly applicable. The developed theory has a direct industrial relevance, which is illustrated with discussions on an automotive engine example. (C) 2017, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.
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| 2. |
- Fu, Jiali, et al.
(författare)
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A Simulation Framework for Off-road Transport Operations using Electric Construction Vehicles
- 2019
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Ingår i: 2019 IEEE INTELLIGENT TRANSPORTATION SYSTEMS CONFERENCE (ITSC). - : IEEE. - 9781538670248 ; , s. 2539-2544
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Konferensbidrag (refereegranskat)abstract
- This paper presents a simulation framework for modeling off-road transport operations at construction worksites using electric construction vehicles. A dynamic model is developed to describe the longitudinal behavior of the electric vehicles, and the outputs from the vehicle dynamic model are fed into a fleet model to evaluate the transport efficiency performance. Discrete event simulation technique is used in the fleet model to represent the logistics of the transport operations and capture the interactions among the vehicles and resources. The simulation framework is applied in a real world quarry operation to study the transport efficiency performance using different number of vehicles. The case study shows that the proposed mechanism can effectively allocate the optimal number of vehicles for the operation and hence serve as an efficient tool in decision-making for construction management.
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| 3. |
- Mohseni, Fatemeh, et al.
(författare)
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Distributed Model Predictive Control for Highway Maneuvers
- 2017
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Ingår i: IFAC PAPERSONLINE. - : ELSEVIER SCIENCE BV. ; , s. 8531-8536
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Konferensbidrag (refereegranskat)abstract
- This paper describes a cooperative control method for autonomous vehicles, in order to perform different traffic maneuvers. The problem is formulated as a distributed optimal control problem for a system of multiple autonomous vehicles with an identified model and then solved using nonlinear Model Predictive Control (MPC). The distributed approach has been used in order to make the problem computationally feasible to be solved in real-time. In the proposed method, each vehicle computes its own control inputs using estimated states of neighboring vehicles. The constraints on the control inputs ensure the comfort of passengers. The method allows us to construct a cost function for several different scenarios in which safety and performing the maneuver constitute two terms of the integrated cost of the finite horizon optimization problem. To provide safety, a potential function is introduced for collision avoidance. Simulation results show that the distributed algorithm scales well with increasing number of vehicles. (C) 2017, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.
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| 4. |
- Mohseni, Fatemeh, et al.
(författare)
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Fuel and Comfort Efficient Cooperative Control for Autonomous Vehicles
- 2017
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Ingår i: 2017 28TH IEEE INTELLIGENT VEHICLES SYMPOSIUM (IV 2017). - : IEEE. - 9781509048045 ; , s. 1631-1636
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Konferensbidrag (refereegranskat)abstract
- In this paper, a cooperative fuel and comfort efficient control for autonomous vehicles is presented in order to perform different traffic maneuvers. The problem is formulated as an optimal control problem in which the cost function takes into account the fuel consumption and passengers comfort, subject to safety and speed constraints. The optimal solution takes into account the comfort and fuel consumption, which is obtained by minimizing a jerk, an acceleration, and a fuel criterion. It is shown that the method can be applied to control different groups of vehicles in different traffic scenarios. Simulation results are used to illustrate the generality property and performance of the proposed approach.
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| 5. |
- Morsali, Mahdi, et al.
(författare)
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Deterministic Trajectory Planning for Non-Holonomic Vehicles Including Road Conditions, Safety and Comfort Factors
- 2019
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Ingår i: IFAC PAPERSONLINE. - : ELSEVIER. ; , s. 97-102
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Konferensbidrag (refereegranskat)abstract
- Deterministic and real time calculation of safe and comfortable speed profiles is the main topic of this paper. Using vehicle properties and road characteristics, such as friction and road banking, safety limits for rollover and skidding are calculated and applied in the trajectory planning. To satisfy comfort criteria and obtain smooth speed profiles, jerk and acceleration of the vehicle are limited in the speed planning algorithm. For speed planner, an A* based search method is used to calculate a speed profile corresponding to shortest traveling time. In order to avoid stationary and moving obstacles, decoupled prioritized planning is used. A physical model is used to define the behavior of the vehicle in the speed planner, where jerk is main parameter for speed planner. The physical model enables the algorithm to take into account the safety and comfort limitations. The results attained from the search method are compared with optimal solutions in different test scenarios and the comparisons show the properties of the algorithm. (C) 2019, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.
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| 6. |
- Morsali, Mahdi, et al.
(författare)
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Real-time velocity planning for heavy duty truck with obstacle avoidance
- 2017
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Ingår i: 2017 28TH IEEE INTELLIGENT VEHICLES SYMPOSIUM (IV 2017). - : IEEE. - 9781509048045 ; , s. 109-114
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Konferensbidrag (refereegranskat)abstract
- A model predictive controller (MPC) including velocity and path planner is designed for real time calculation of a safe and comfortable velocity and steer angle in a heavy duty vehicle. The calculation time is reduced by finding, based on measurement data, simple roll and motion model. The roll dynamics of the truck is constructed using identification of proposed roll model and it is validated by measurements logged by a heavy duty truck and the suggested model shows good agreement with the measurement data. The safety issues such as rollover prevention and moving obstacle avoidance are taken into account. To increase comfort, acceleration, jerk, steer angle and steer angle rate are limited. The simulation and control algorithm is tested in different scenarios, where the test results show the properties of the algorithm.
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| 7. |
- Morsali, Mahdi, 1990-, et al.
(författare)
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Trajectory Planning for Autonomous Vehicles in Time Varying Environments Using Support Vector Machines
- 2018
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Ingår i: 2018 29TH IEEE INTELLIGENT VEHICLES SYMPOSIUM, IEEE , 2018, p. 109-114. - China : IEEE conference proceedings.
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Konferensbidrag (refereegranskat)abstract
- A novel trajectory planning method is proposedin time varying environments for highway driving scenarios.The main objective is to ensure computational efficiency in theapproach, while still ensuring collision avoidance with movingobstacles and respecting vehicle constraints such as comfortcriteria and roll-over limits. The trajectory planning problemis separated into finding a collision free corridor in space-time domain using a support vector machine (SVM), whichmeans solving a convex optimization problem. After that atime-monotonic path is found in the collision free corridor bysolving a simple search problem that can be solved efficiently.The resulting path in space-time domain corresponds to theresulting planned trajectory of the vehicle. The planner is adeterministic search method associated with a cost functionthat keeps the trajectory kinematically feasible and close to themaximum separating surface, given by the SVM. A kinematicmotion model is used to construct motion primitives in thespace-time domain representing the non-holonomic behavior ofthe vehicle and is used to ensure physical constraints on thestates of the vehicle such as acceleration, speed, jerk, steer andsteer rate. The speed limits include limitations by law and alsorollover speed limits. Two highway maneuvers have been usedas test scenarios to illustrate the performance of the proposedalgorithm.
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| 8. |
- Morsali, Mahdi, et al.
(författare)
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Trajectory Planning in Traffic Scenarios Using Support Vector Machines
- 2019
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Ingår i: IFAC PAPERSONLINE. - : ELSEVIER. ; , s. 91-96
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Konferensbidrag (refereegranskat)abstract
- Finding safe and collision free trajectories in an environment with moving obstacles is central for autonomous vehicles but at the same time a complex task. A reason is that the search space in space-time domain is very complex. This paper proposes a two-step approach where in first step, the search space for trajectory planning is simplified by solving a convex optimization problem formulated as a Support Vector Machine resulting in an obstacle free corridor that is suitable for a trajectory planner. Then, in a second step, a basic A* search strategy is used in the obstacle free search space. Due to the physical model used, the comfort and safety criteria are applied while searching the trajectory. The vehicle rollover prevention is used as a safety criterion and the acceleration, jerk and steering angle limits are used as comfort criteria. For simulations, urban environments with intersections and vehicles as moving obstacles are constructed. The properties of the approach are examined by the simulation results. (C) 2019, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.
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| 9. |
- Åslund, Jan, et al.
(författare)
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Asymptotic behavior of a fault diagnosis performance measure for linear systems
- 2019
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Ingår i: Automatica. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0005-1098 .- 1873-2836. ; 106, s. 143-149
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Tidskriftsartikel (refereegranskat)abstract
- Fault detection and fault isolation performance of a model based diagnosis system mainly depends on the level of model uncertainty and the time allowed for detection. The longer time for detection that can be accepted, the more certain detection can be achieved and the main objective of this paper is to show how the window length relates to a diagnosis performance measure. A key result is an explicit expression for asymptotic performance with respect to window length and it is shown that there exists a linear asymptote as the window length tends to infinity. The gradient of the asymptote is a system property that can be used in the evaluation of diagnosis performance when designing a system. A key property of the approach is that the model of the system is analyzed directly, which makes the approach independent of detection filter design. (C) 2019 Elsevier Ltd. All rights reserved.
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