Operational Concepts for Truck Maneuvers with Cooperative Adaptive Cruise Control (original) (raw)
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Cooperative Adaptive Cruise Control (CACC) for Truck Platooning: Operational Concept Alternatives
RePEc: Research Papers in Economics, 2015
The concept of truck platooning has been the focus of many research projects over the years at the California PATH Program and around the world through such projects as CHAUFFEUR, SARTRE, KONVOI, Energy ITS, and COMPANION. These previous projects have included the automation of both lateral and longitudinal control in the following trucks because of the very close following distances targeted by those projects. Cooperative Adaptive Cruise Control (CACC) provides an intermediate step toward a longer-term vision of trucks operating in closely-coupled automated platoons on both long-haul and short-haul freight corridors. There are important distinctions between CACC and automated truck platooning. First, with CACC, only truck speed control will be automated, using V2V communication to supplement forward sensors. The drivers will still be responsible for actively steering the vehicle, lane keeping, and monitoring roadway and traffic conditions. Second, while truck platooning systems have relied on a Constant Distance Gap (CDG) control strategy, CACC has relied on a Constant-Time Gap (CTG) control strategy, where the distance between vehicles is proportional to the speed. For these reasons, a series of trucks using CACC is referred to as a string, rather than a platoon. This report mainly focuses on describing the various CACC operational concept alternatives at the level of individual vehicles, local groups of vehicles and their drivers, and which alternatives should be employed in this research project. These operational concepts can be broken into four categories: string formation, steady-state cruising, string split maneuvers, and faults or abnormal operating conditions.
Cooperative Adaptive Cruise Control (CACC) For Partially Automated Truck Platooning:Final Report
RePEc: Research Papers in Economics, 2018
Cooperative Adaptive Cruise Control (CACC) provides an intermediate step toward a longerterm vision of trucks operating in closely-coupled automated platoons on both long-haul and short-haul freight corridors. There are important distinctions between CACC and automated truck platooning. First, with CACC, only truck speed control will be automated, using V2V communication to supplement forward sensors. The drivers will still be responsible for actively steering the vehicle, lane keeping, and monitoring roadway and traffic conditions. Second, while truck platooning systems have relied on a Constant Distance Gap (CDG) control strategy, CACC has relied on a Constant-Time Gap (CTG) control strategy, where the distance between vehicles is proportional to the speed. A CACC system has been implemented on three Volvo Class-8 truck tractors and has been tested under a variety of conditions to assess its potential impacts if introduced into public use. The vehicle-following control system performance has been tested to demonstrate its ability to maintain accurate spacing between the trucks with reasonably smooth ride quality, and to respond safely to cut-in maneuvers by drivers of other vehicles. The energy saving potential of the close formation driving of the trucks has been tested through an extensive set of test-track experiments under a range of speeds, with and without aerodynamic improvements to the trailers, showing that the closer separations and trailer aerodynamic improvements have a more than additive contribution to fuel economy. Truck driver responses to the CACC system have been assessed through an on-road experiment with nine test drivers, who provided their opinions about the system in questionnaire responses and demonstrated which gap settings they preferred to use while driving in mixed public traffic on California freeways. The larger-scale impacts of truck CACC on traffic flow and energy consumption were assessed in a traffic microsimulation of a high-density urban freeway with heavy truck traffic. A baseline condition with all manual driving was compared with a scenario in which all the heavy trucks used CACC, showing how this could relieve traffic bottlenecks and improve the speed and smoothness of traffic for all vehicles on the freeway. The trucks saved time and energy in this scenario, and because the speeds were only moderate the energy savings were primarily from the reductions in speed variations rather than from aerodynamic drag reductions.
Cooperative Adaptive Cruise Control (Cacc) Definitions and Operating Concepts
Cooperative Adaptive Cruise Control (CACC) includes multiple concepts of communicationenabled vehicle following and speed control. This paper presents definitions and classifications to help clarify the distinctions among different types of automatic vehicle following control that are often conflated with each other. A distinction is made between V2V CACC, based on vehicle-vehicle cooperation, and I2V CACC, in which the infrastructure provides information or guidance to the CACC system (such as the target set speed value). In V2V CACC, communication provides enhanced information so that vehicles can follow their predecessors with higher accuracy, faster response, and shorter gaps, resulting in enhanced traffic flow stability and possibly improved safety. A further distinction is made between CACC, which uses constant-time-gap vehicle following (forming CACC strings), and automated platooning, which uses tightly-coupled, constant-clearance, vehicle-following strategies. Although ACC ...
Cooperative Adaptive Cruise Control
Transportation Research Record: Journal of the Transportation Research Board, 2015
Cooperative adaptive cruise control (CACC) includes multiple concepts of communication-enabled vehicle following and speed control. Definitions and classifications are presented to help clarify the distinctions between types of automated vehicle-following control that are often conflated with each other. A distinction is made between vehicle-to-vehicle (V2V) CACC, based on vehicle–vehicle cooperation, and infrastructure-to-vehicle CACC, in which the infrastructure provides information or guidance to the CACC system (such as the target set speed value). In V2V CACC, communication provides enhanced information so that vehicles can follow their predecessors with higher accuracy, faster response, and shorter gaps; the result would be enhanced traffic flow stability and possibly improved safety. A further distinction is made between CACC, which uses constant-time-gap vehicle following (forming CACC strings), and automated platooning, which uses tightly coupled, constant-clearance, vehicl...
Transportation Research Record: Journal of the Transportation Research Board
Cooperative adaptive cruise control (CACC) systems have the potential to improve traffic flow and fuel efficiency, but these effects are challenging to estimate. This paper reports the development of a micro-simulation model to represent these impacts for heavy trucks using CACC when they share a freeway with manually driven passenger cars. The simulation incorporates automated truck-following models that have been derived from experimental data recorded on heavy trucks driven under CACC, adaptive cruise control (ACC), and conventional cruise control (CC). The simulation includes other behavioral models for lane changing, lane change cooperation and lane use restrictions for trucks to better capture real-world traffic dynamics. The paper explains the calibration of the simulation method for a 15-mile urban freeway corridor with heavy truck traffic and significant congestion. Simulation results for different market penetration rates show that truck CACC improved traffic operations fo...
Design and experimental evaluation of cooperative adaptive cruise control
2011 14th International IEEE Conference on Intelligent Transportation Systems (ITSC), 2011
Road throughput can be increased by driving at small inter-vehicle time gaps. The amplification of velocity disturbances in upstream direction, however, poses limitations to the minimum feasible time gap. String-stable behavior is thus considered an essential requirement for the design of automatic distance control systems, which are needed to allow for safe driving at time gaps well below 1 s. Theoretical analysis reveals that this requirement can be met using wireless intervehicle communication to provide real-time information of the preceding vehicle, in addition to the information obtained by common Adaptive Cruise Control (ACC) sensors. In order to validate these theoretical results and to demonstrate the technical feasibility, the resulting control system, known as Cooperative ACC (CACC), is implemented on a test fleet consisting of six passenger vehicles. Experiments clearly show that the practical results match the theoretical analysis, thereby indicating the possibilities for short-distance vehicle following.
2018 21st International Conference on Intelligent Transportation Systems (ITSC), 2018
Connected and automated vehicles (CAVs) have the potential to address the safety, mobility and sustainability issues of our current transportation systems. Cooperative adaptive cruise control (CACC), for example, is one promising technology to allow CAVs to be driven in a cooperative manner and introduces system-wide benefits. In this paper, we review the progress achieved by researchers worldwide regarding different aspects of CACC systems. Literature of CACC system architectures are reviewed, which explain how this system works from a higher level. Different control methodologies and their related issues are reviewed to introduce CACC systems from a lower level. Applications of CACC technology are demonstrated with detailed literature, which draw an overall landscape of CACC, point out current opportunities and challenges, and anticipate its development in the near future.
Influences on Energy Savings of Heavy Trucks Using Cooperative Adaptive Cruise Control
SAE Technical Paper Series, 2018
A n integrated adaptive cruise control (ACC) and cooperative ACC (CACC) was implemented and tested on three heavy-duty tractor-trailer trucks on a closed test track. The first truck was always in ACC mode, and the followers were in CACC mode using wireless vehicle-vehicle communication to augment their radar sensor data to enable safe and accurate vehicle following at short gaps. The fuel consumption for each truck in the CACC string was measured using the SAE J1321 procedure while travelling at 65 mph and loaded to a gross weight of 65,000 lb, demonstrating the effects of: inter-vehicle gaps (ranging from 3.0 s or 87 m to 0.14 s or 4 m, covering a much wider range than previously reported tests), cut-in and cutout maneuvers by other vehicles, speed variations, the use of mismatched vehicles (standard trailers mixed with aerodynamic trailers with boat tails and side skirts), and the presence of a passenger vehicle ahead of the platoon. The results showed that energy savings generally increased in a non-linear fashion as the gap was reduced. The middle truck saved the most fuel at gaps shorter than 12 m and the trailing truck saved the most at longer gaps, while lead truck saved the least at all gaps. The cut-in and cutout maneuvers had only a marginal effect on fuel consumption even when repeated every two miles. The presence of passenger-vehicle traffic had a measurable impact. The fuel-consumption savings on the curves was less than on the straight sections.
Developing a platoon-wide Eco-Cooperative Adaptive Cruise Control (CACC) system
2017 IEEE Intelligent Vehicles Symposium (IV), 2017
technology has become increasingly popular. As an example, Cooperative Adaptive Cruise Control (CACC) systems are of high interest, allowing CAVs to communicate and cooperate with each other to form platoons, where one vehicle follows another with a predefined spacing or time gap. Although numerous studies have been conducted on CACC systems, very few have examined the protocols from the perspective of environmental sustainability, not to mention from a platoonwide consideration. In this study, we propose a vehicle-to-vehicle (V2V) communication based Eco-CACC system, aiming to minimize the platoon-wide energy consumption and pollutant emissions at different stages of the CACC operation. A full spectrum of environmentally-friendly CACC maneuvers are explored and the associated protocols are developed, including sequence determination, gap closing and opening, platoon cruising with gap regulation, and platoon joining and splitting. Simulation studies of different scenarios are conducted using MATLAB/Simulink. Compared to an existing CACC system, the proposed one can achieve additional 2% energy savings and additional 17% pollutant emissions reductions during the platoon joining scenario.