| 1. |
- Alam, Assad, et al.
(författare)
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Heavy-Duty Vehicle Platooning for Sustainable Freight Transportation A COOPERATIVE METHOD TO ENHANCE SAFETY AND EFFICIENCY
- 2015
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Ingår i: IEEE CONTROL SYSTEMS MAGAZINE. - 1066-033X. ; 35:6, s. 34-56
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Tidskriftsartikel (refereegranskat)abstract
- The current system of global trade is largely based on transportation and communication technology from the 20th century. Advances in technology have led to an increasingly interconnected global market and reduced the costs of moving goods, people, and technology around the world [1]. Transportation is crucial to society, and the demand for transportation is strongly linked to economic development. Specifically, road transportation is essential since about 60% of all surface freight transportation (which includes road and rail transport) is done on roads [2]. Despite the important role of road freight transportation in the economy, it is facing serious challenges, such as those posed by increasing fuel prices and the need to reduce greenhouse gas emissions. On the other hand, the integration of information and communication technologies to transportation systems-leading to intelligent transportation systems-enables the development of cooperative methods to enhance the safety and energy efficiency of transportation networks. This article focuses on one such cooperative approach, which is known as platooning. The formation of a group of heavy-duty vehicles (HDVs) at close intervehicular distances, known as a platoon (see Figure 1) increases the fuel efficiency of the group by reducing the overall air drag. The safe operation of such platoons requires the automatic control of the velocity of the platoon vehicles as well as their intervehicular distance. Existing work on platooning has focused on the design of controllers for these longitudinal dynamics, in which simple vehicle models are typically exploited and perfect environmental conditions, such as flat roads, are generally assumed. The broader perspective of how platooning can be effectively exploited in a freight transportation system has received less attention. Moreover, experimental validations of the fuel-saving potential offered by platooning have typically been performed by reproducing the perfect conditions as assumed in the design of the automatic controllers. This article focuses on these two aspects by addressing the following two objectives.
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| 2. |
- Besselink, Bart, et al.
(författare)
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Cyber-Physical Control of Road Freight Transport
- 2016
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Ingår i: Proceedings of the IEEE. - : IEEE. - 0018-9219 .- 1558-2256. ; 104:5, s. 1128-1141
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Tidskriftsartikel (refereegranskat)abstract
- Freight transportation is of outmost importance in our society and is continuously increasing. At the same time, transporting goods on roads accounts for about 26% of the total energy consumption and 18% of all greenhouse gas emissions in the European Union. Despite the influence the transportation system has on our energy consumption and the environment, road transportation is mainly done by individual long-haulage trucks with no real-time coordination or global optimization. In this paper, we review how modern information and communication technology supports a cyber-physical transportation system architecture with an integrated logistic system coordinating fleets of trucks traveling together in vehicle platoons. From the reduced air drag, platooning trucks traveling close together can save about 10% of their fuel consumption. Utilizing road grade information and vehicle-to-vehicle communication, a safe and fuel-optimized cooperative look-ahead control strategy is implemented on top of the existing cruise controller. By optimizing the interaction between vehicles and platoons of vehicles, it is shown that significant improvements can be achieved. An integrated transport planning and vehicle routing in the fleet management system allows both small and large fleet owners to benefit from the collaboration. A realistic case study with 200 heavy-duty vehicles performing transportation tasks in Sweden is described. Simulations show overall fuel savings at more than 5% thanks to coordinated platoon planning. It is also illustrated how well the proposed cooperative look-ahead controller for heavy-duty vehicle platoons manages to optimize the velocity profiles of the vehicles over a hilly segment of the considered road network.
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| 3. |
- 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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| 4. |
- 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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| 5. |
- Liang, Kuo-Yun, et al.
(författare)
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Networked control challenges in collaborative road freight transport
- 2016
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Ingår i: European Journal of Control. - : European Control Association. - 0947-3580 .- 1435-5671. ; 30, s. 2-14
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Tidskriftsartikel (refereegranskat)abstract
- Freight transport is of major importance for the European economy and is growing thanks to increasing global trade. About three quarters of inland freight transport in the European Union is on roads. It has the potential to go through a dramatic change over the next decades thanks to the recent development of technologies such as wireless communication, cloud computing, sensor devices, and vehicle electronics. They enable a new integrated goods transport system based on optimized logistics, real-time traffic information, vehicular communications, collaborative driving, and autonomous vehicles. In this paper, we discuss challenges in creating a more efficient and sustainable goods road transportation system and how some of them can be tackled with a networked control approach. In particular, we discuss a method to improve the efficiency of the transportation system by minimizing the number of empty transports needed to fulfill the assignments on a given road network. Assignments with overlapping route segments might lead to further improvements, as the formation of vehicle platoons yields reduced fuel consumption. For realistic scenarios, it is shown that such collaboration opportunities arise already with relatively few vehicles. The fuel-efficient formation and control of platoons is also discussed. Some of the presented methods have been tested on real vehicles in traffic. The paper shows experimental results on automatic formation of vehicle platoons on a Swedish highway. The influence of traffic density on the merge maneuver is illustrated. The results indicate that platoon coordination could be improved by support from appropriate traffic monitoring technologies.
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| 6. |
- 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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| 7. |
- 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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| 8. |
- Turri, Valerio, et al.
(författare)
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A model predictive controller for non-cooperative eco-platooning
- 2017
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Ingår i: 2017 American Control Conference (ACC) 24-26 May 2017. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781509059928 ; , s. 2309-2314
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Konferensbidrag (refereegranskat)abstract
- This paper proposes an energy-saving adaptive cruise control (ACC) which exploits the future trajectory of the preceding vehicle to minimize unnecessary braking. By suitable design of the model predictive control terminal set, the proposed eco-ACC avoids unnecessary braking and improves fuel economy, while guaranteeing safety and limited online computational burden. Simulations and experiments show the efficacy of the approach and confirm fuel saving, when the eco-ACC is compared to baseline ACC formulations.
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| 9. |
- Turri, Valerio, et al.
(författare)
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Cooperative look-ahead control for fuel-efficient and safe heavy-duty vehicle platooning
- 2016
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Ingår i: IEEE Transactions on Control Systems Technology. - : IEEE. - 1063-6536 .- 1558-0865. ; 25:1, s. 12-28
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Tidskriftsartikel (refereegranskat)abstract
- The operation of groups of heavy-duty vehicles (HDVs) at a small inter-vehicular distance (known as platoon) allows to lower the overall aerodynamic drag and, therefore, to reduce fuel consumption and greenhouse gas emissions. However, due to the large mass and limited engine power of HDVs, slopes have a significant impact on the feasible and optimal speed profiles that each vehicle can and should follow. Therefore maintaining a short inter-vehicular distance as required by platooning without coordination between vehicles can often result in inefficient or even unfeasible trajectories. In this paper we propose a two-layer control architecture for HDV platooning aimed to safely and fuel-efficiently coordinate the vehicles in the platoon. Here, the layers are responsible for the inclusion of preview information on road topography and the real-time control of the vehicles, respectively. Within this architecture, dynamic programming is used to compute the fuel-optimal speed profile for the entire platoon and a distributed model predictive control framework is developed for the real-time control of the vehicles. The effectiveness of the proposed controller is analyzed by means of simulations of several realistic scenarios that suggest a possible fuel saving of up to 12% for the follower vehicles compared to the use of standard platoon controllers.
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| 10. |
- 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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| 11. |
- Turri, Valerio, et al.
(författare)
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Fuel-efficient heavy-duty vehicle platooning by look-ahead control
- 2014
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Ingår i: Decision and Control (CDC), 2014 IEEE 53rd Annual Conference on. - : IEEE conference proceedings. - 9781479977468 ; , s. 654-660
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Konferensbidrag (refereegranskat)abstract
- The operation of groups of heavy-duty vehicles at close intervehicular distances (known as platoons) has been shown to be an effective way of reducing fuel consumption. For single vehicles, it is also known that the availability of preview information on the road topography can be exploited to obtain fuel savings. The current paper aims at the inclusion of preview information in platooning by introducing a two-layer control system architecture for so-called look-ahead platooning. Here, the layers are responsible for the inclusion of preview information and real-time vehicle control for platooning, respectively. Within this framework, a control strategy is presented, where dynamic programming is used for the calculation of fuel-optimal speed profiles, while a model predictive control approach is exploited for the real-time vehicle control. The feasibility of this approach is illustrated by means of the simulation of relevant scenarios.
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| 12. |
- Turri, Valerio, et al.
(författare)
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Gear management for fuel-efficient heavy-duty vehicle platooning
- 2016
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Ingår i: 2016 IEEE 55TH CONFERENCE ON DECISION AND CONTROL (CDC). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781509018376 ; , s. 1687-1694
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Konferensbidrag (refereegranskat)abstract
- Vehicle platooning has great potential for the reduction of greenhouse gas emissions and fuel consumption of heavy-duty vehicles. However, previous works on fuel-efficient platoon control largely ignore the effect of gear changes, even though experimental studies have shown that gear shifts have a large impact on the behavior and fuel consumption of vehicle platoons. In particular, the interruption in traction force during a gear shift can cause large deviations in the tracking of the reference speed and inter-vehicle distance and can result in the braking of the vehicles. In this paper, we discuss a control architecture that includes the management of gear shifts and we propose a method to select the gears that takes fuel-efficiency into account, but also targets the good behavior of the platoon. In detail, the proposed method is based on a dynamic programming formulation that computes the optimal sequence of gear shifts necessary for the fuel-efficient and smooth tracking of a given reference speed profile. The performance of the proposed approach is finally analyzed by means of simulations by comparing it with the performance of alternative solutions.
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| 13. |
- 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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| 14. |
- Turri, Valerio
(författare)
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Look-ahead control for fuel-efficient and safe heavy-duty vehicle platooning
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The operation of heavy-duty vehicles at small inter-vehicular distances, known as platoons, lowers the aerodynamic drag and, therefore, reduces fuel consumption and greenhouse gas emissions. Tests conducted on flat roads have shown the potential of platooning to reduce the fuel consumption of about 10%. However, platoons are expected to operate on public highways with varying topography alongside other vehicles. Due to the large mass and limited engine power of heavy-duty vehicles, road slopes have a significant impact on feasible and optimal speed profiles. For single vehicles, experiments have shown that optimizing the speed according to the road profile resulted in fuel saving of up to 3.5%. The use of such a look-ahead control framework is expected to lead to large benefits also for platooning.This thesis presents the design of safe and fuel-efficient control of heavy-duty vehicle platoons driving on realistic road profiles. The scenario where the platooning vehicles cooperate to optimize their overall fuel-efficiency is studied together with the scenario where the vehicles do not explicitly cooperate.First, we propose a control architecture that splits the cooperative platooning control problem into two layers. The top layer computes a reference speed profile that ensures fuel-efficient operation of the entire platoon based on dynamic programming. The bottom layer relies on model predictive control to safely track the reference speed. Simulations show the ability of the proposed controller to save up to 12% of fuel for following vehicles compared to existing platoon controllers and to safely react to emergency braking of the leading vehicle.Second, we propose a gear management layer that fits in the cooperative platooning control architecture and explicitly takes the gear selection into account. The underlying optimal control problem aims at minimizing the vehicle fuel consumption and the reference tracking deviations. Simulations indicate how this formulation outperforms existing alternatives, both in terms of fuel-efficiency and tracking error.Third, we address non-cooperative platooning by proposing a vehicle-following controller suitable for fuel-efficient control of heavy-duty vehicles. The proposed controller explores both the benefits given by the short inter-vehicular distance and those given by pulse-and-glide, i.e., alternating traction and coasting phases. A simulation study suggests fuel saving of up to 18% compared to the single vehicle case, and up to 7% compared to when a constant-distance vehicle-following controller is used.Last, we propose a vehicle-following controller aimed at exploiting long preview of the preceding vehicle trajectory by directly manipulating the inputs of low-level vehicle controllers. This is achieved through a model predictive controller that uses a short prediction horizon and includes a terminal state set that incorporates preview information about the preceding vehicle. Experiments indicate the ability of the controller to avoid unnecessary braking, while simulations show behavior similar to the optimal control behavior.
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| 15. |
- 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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