| 1. |
- Corno, Matteo, et al.
(författare)
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Control-Oriented Modeling of Motorcycle Dynamics
- 2012
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Ingår i: IFAC Proceedings Volumes. - : IFAC Papers Online. - 9783902823069 ; , s. 769-774
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Konferensbidrag (refereegranskat)abstract
- Recent technology advances in the field of ride-by-wire technology for motorcycle (namely active braking and full electronic throttle) open the way to the design of innovative control strategies to improve two-wheeled vehicles stability. As such, it is of growing importance to devise control oriented models of the bike dynamics to be employed for control design purposes. This paper proposes an analytical model of a two-wheeled vehicle tuned to capture the coupling between longitudinal variables (i.e. traction and braking torque) and out-of-plane modes. The model is derived from first principles. The model parameters are identified from a complete multi-body simulator. The proposed model offers a good tradeoff between complexity and accuracy.
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| 2. |
- Johansson, Alexander, et al.
(författare)
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Truck Platoon Formation at Hubs : An Optimal Release Time Rule
- 2020
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Ingår i: Ifac papersonline. - : Elsevier BV. - 2405-8963. ; , s. 15312-15318
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Konferensbidrag (refereegranskat)abstract
- We consider a hub-based platoon coordination problem in which vehicles arrive at a hub according to an independent and identically distributed stochastic arrival process. The vehicles wait at the hub, and a platoon coordinator, at each time-step, decides whether to release the vehicles from the hub in the form of a platoon or wait for more vehicles to arrive. The platoon release time problem is modeled as a stopping rule problem wherein the objective is to maximize the average platooning benefit of the vehicles located at the hub and there is a cost of having vehicles waiting at the hub. We show that the stopping rule problem is monotone and the optimal platoon release time policy will therefore be in the form of a one time-step look-ahead rule. The performance of the optimal release rule is numerically compared with (i) a periodic release time rule and (ii) a non-causal release time rule where the coordinator knows all the future realizations of the arrival process. Our numerical results show that the optimal release time rule achieves a close performance to that of the non-causal rule and outperforms the periodic rule, especially when the arrival rate is low.
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| 3. |
- Na, G., et al.
(författare)
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Disturbance observer approach for fuel-efficient heavy-duty vehicle platooning
- 2019
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Ingår i: Vehicle System Dynamics. - : Taylor and Francis Ltd.. - 0042-3114 .- 1744-5159.
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Tidskriftsartikel (refereegranskat)abstract
- Heavy-duty vehicle platooning has received much attention as a method to reduce fuel consumption by keeping inter-vehicle distance short. When a platoon follows a fuel-optimal velocity profile calculated using preview road slope information, significant improvement in the fuel economy occurs. To calculate the optimal velocity in the existing method, however, platoon should acquire expensive road slope data in advance. As an alternative, we propose a road slope estimation method, which enables platoon to calculate the optimal velocity profile without the usage of actual road slope data. Other major challenges in platoon operation include overcoming the effect of the vehicle model uncertainties and external disturbances for ensuring the control performance. The most significant part of the disturbances arises from slopes along a route. Existing method for reducing the effect of the slope employs a feed-forward type compensation in the control loop by combining the vehicle position acquired from GPS and the slope database. However, this method exhibits limitations: the mass of the vehicles in the platoon is uncertain which lowers the accuracy of the feed-forward compensation, and the platoon requires the pre-acquired slope database. To overcome these limitations, we propose an alternative method employing disturbance observer. Simulations of various scenarios are conducted to show the efficacy of the proposed method using the actual road slope data of a Swedish highway.
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| 4. |
- Nigicser, David, 1992-, et al.
(författare)
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Predictive Vehicle Motion Control for Post-Crash Scenarios
- 2018
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Konferensbidrag (refereegranskat)abstract
- This paper presents an active safety system for passenger vehicles designed to mitigate secondary collisions after an initial impact. Thecontrol objective is to minimize lateral deviation from the known original path while achieving a safe heading angle after the initialcollision. A hierarchical controller architecture is proposed: the higher layer is formulated as a linear time-varying model predictivecontroller that defines the virtual control moment input; the lower layer deploys a rule-based controller that realizes the requestedmoment. The designed control system is tested and validated on a high-fidelity vehicle dynamics simulator.
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| 5. |
- Turri, Valerio, 1987-
(författare)
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Fuel-efficient and safe heavy-duty vehicle platooning through look-ahead control
- 2015
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The operation of groups of heavy-duty vehicles at small inter-vehicular distances, known as platoons, lowers the overall aerodynamic drag and, therefore, reduces fuel consumption and greenhouse gas emissions. Experimental tests conducted on a flat road and without traffic have shown that platooning has the potential to reduce the fuel consumption up to 10%. However, platoons are expected to drive on public highways with varying topography and traffic. Due to the large mass and limited engine power of heavy-duty vehicles, road slopes can have a significant impact on feasible and optimal speed profiles. Therefore, maintaining a short inter-vehicular distance without coordination can result in inefficient or even infeasible speed trajectories. Furthermore, external traffic can interfere by affecting fuel-efficiency and threatening the safety of the platooning vehicles.This thesis addresses the problem of safe and fuel-efficient control for heavy-duty vehicle platooning. We propose a hierarchical control architecture that splits this complex control problem into two layers. The layers are responsible for the fuel-optimal control based on look-ahead information on road topography and the real-time vehicle control, respectively. The top layer, denoted the platoon coordinator, relies on a dynamic programming framework that computes the fuel-optimal speed profile for the entire platoon. The bottom layer, denoted the vehicle control layer, uses a distributed model predictive controller to track the optimal speed profile and the desired inter-vehicular spacing policy. Within this layer, constraints on the vehicles' states guarantee the safety of the platoon. The effectiveness of the proposed controller is analyzed by means of simulations of several realistic scenarios. They suggest a possible fuel saving of up to 12% for the follower vehicles compared to the use of existing platoon controllers. Analysis of the simulation results shows how the majority of the fuel saving comes from a reduced usage of vehicles brakes.A second problem addressed in the thesis is model predictive control for obstacle avoidance and lane keeping for a passenger car. We propose a control framework that allows to control the nonlinear vehicle dynamics with linear model predictive control. The controller decouples the longitudinal and lateral vehicle dynamics into two successive stages. First, plausible braking and throttle profiles are generated. Second, for each profile, linear time-varying models of the lateral dynamics are derived and used to formulate a collection of linear model predictive control problems. Their solution provides the optimal control input for the steering and braking actuators. The performance of the proposed controller has been evaluated by means of simulations and real experiments.
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| 6. |
- Turri, Valerio, 1987-, et al.
(författare)
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Linear model predictive control for lane keeping and obstacle avoidance on low curvature roads
- 2013
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Ingår i: IEEE Conference on Intelligent Transportation Systems, Proceedings, ITSC. - : IEEE conference proceedings. - 9781479929146 ; , s. 378-383
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Konferensbidrag (refereegranskat)abstract
- This paper presents a control architecture based on a linear MPC formulation that addresses the lane keeping and obstacle avoidance problems for a passenger car driving on low curvature roads. The proposed control design decouples the longitudinal and lateral dynamics in two successive stages. First, plausible braking or throttle profiles are defined over the prediction horizon. Then, based on these profiles, linear time-varying models of the vehicle lateral dynamics are derived and used to formulate the associated linear MPC problems. The solutions of the optimization problems are used to determine for every time step, the optimal braking or throttle command and the corresponding steering angle command. Simulations show the ability of the controller to overcome multiple obstacles and keep the lane. Experimental results on an autonomous passenger vehicle driving on slippery roads show the effectiveness of the approach.
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| 7. |
- Valerio, Turri, 1987-, et al.
(författare)
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Fuel-optimal look-ahead adaptive cruise control for heavy-duty vehicles
- 2018
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Ingår i: 2018 Annual American Control Conference (ACC). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781538654286 ; , s. 1841-1848
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Konferensbidrag (refereegranskat)abstract
- In this paper, we investigate the problem of how to optimally control a heavy-duty vehicle following another one, commonly referred as ad-hoc or non-cooperative platooning. The problem is formulated as an optimal control problem that exploits road topography information and the knowledge of the preceding vehicle speed trajectory to compute the optimal engine torque and gear request for the vehicle under control. The optimal control problem is implemented by dynamic programming and is tested in a simulation study that compares the performance of multiple longitudinal control strategies. The proposed look-ahead adaptive cruise controller is able to achieve fuel saving up to 7% with respect to the use of a reference vehicle-following controller, by combining the benefits of adjusting the inter-vehicular distance according to the future slope with those of alternating phases of throttling and freewheeling (driving in neutral gear).
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