Designing and Evaluation

Design of Platoon Controller with V2V Communication for Highways

ABSTRACT The capability of vehicles to communicate wirelessly provides an opportunity for innovations in the transport sector. Platooning of vehicles is one of the widely studied topics in the research community. Vehicle platooning aims to increase the capacity of roads, improve traffic safety, and reduce fuel consumption. The goal of this chapter is to introduce the reader to the subject of vehicle dynamics on modelling and control aspects and observe the behavior with vehicle-to-vehicle (V2V) communication constraints. The proposed algorithms are presented in general form and are applicable to any vehicle.

Most of the work on platooning investigates the control of vehicles in pairs based on the concept of look-ahead platooning. This chapter emphasizes the design of proportional integral derivative (PID) controllers and model predictive control (MPC) based on a combination of constant distance (CD) and constant headway time (CHT) policies to operate a heavy-duty vehicle platoon. In addition to basic cooperative adaptive cruise control (CACC), the controller is tested and verified for carrying out splitting and merging maneuvers.

Furthermore, the controller performance is analyzed with V2V communication constraints between the vehicles. Computer simulations were carried out to test the effectiveness of the controller. MATLAB, VISSIM, and a network simulator (NS3) are combined to form an integrated simulation. The platooning operations and merging and splitting maneuvers are replicated as realistically as possible while considering the effects of neighboring V2V equipped traffic. The speed, acceleration, and inter-vehicular distance profiles of the platoon were observed. It is evident from the profiles that the followers track the header vehicle and maintain a constant distance and time gap in the presence of frequent speed variations by the header vehicle.

The packet delivery ratio (PDR) of the platoon vehicles is determined in the case of external disturbance due to the V2V-equipped surrounding vehicles. The PDR can be used to establish a correlation between communication and controller performance. Finally, this chapter also presents an analysis of packet drops in vehicle platooning using V2V communication, where deliberate communication failures are introduced through NS3.

Introduction

Potential researchers in the transportation sector and academia, who are working in the vehicle-to-everything (V2X) domain, will be interested to see the impact of V2X on real-life traffic conditions. The primary motive of this chapter is to present innovations on connected transportation systems that demonstrate a new way of achieving improvements in safety, fuel consumption, and mobility.

Advancements in V2X technology involve V2X application development to enhance traffic systems. However, experimentations are not practical in the prototype development stages. To counter this problem, the research community has proposed several simulators that enable the study of V2X applications. Since there is no standalone package to study V2X applications, several integrated architectures are designed using existing software packages. In this research study, an integrated simulator framework is set up for testing V2X protocols and applications. Several V2X-based applications, such as green light optimized speed advisory (GLOSA), platooning, and intersection collision avoidance, are studied using the simulator. This enables us to study the impact of V2X on real-life traffic conditions. This chapter focuses on the design of the platoon controller with vehicle-to-vehicle (V2V) communication for highways.

Truck platooning is one of the more complex V2X-based applications and involves vehicles traveling together in a pattern. In long-distance travel, platooning provides a significant reduction in fuel consumption, thereby reducing the cost of operation and air pollution. The most common pattern is a straight line with vehicles moving one behind the other in the same lane on highways. The first vehicle sets the pace, and the remaining vehicles adjust their speed to match the first vehicle. A significant proportion of air-drag is reduced by making the vehicles follow each other in close-range [1]. This results in a reduction in fuel consumption. Throughout the world, freight transport consumes a million tons of fuel every year. Hence, even a modest decrease in fuel consumption makes a significant difference on a broader scale. Additionally, platooning increases roadway capacity [2].

The challenge in platooning is to develop a capable controller that can keep the vehicles at a close-range, track the abrupt speed changes of the first vehicle, and avoid collisions among the platoon members [3]. Most of the earlier work on the platoon controller design entails the use and development of an adaptive cruise control (ACC) strategy [4]. In the ACC system, a controlled vehicle obtains the speed and position of the immediate neighboring vehicles to calculate its control input. Radar communication is used for communication between the platoon members. Due to the inherent time-delays in radar communication, it is unreliable in emergencies [5]. To overcome the shortcomings of the ACC strategy, researchers proposed an advanced version of ACC, called cooperative adaptive cruise control (CACC). CACC strategy uses wireless communication, such as 5.9 GHz dedicated short-range communications (DSRC) or 5G to exchange data among the platoon members. The use of wireless communication allows low latency and high-frequency data exchange of a wide range of data such as GPS position, inertial measurement unit data, and the control actions like throttle or brake. Access to more data helps in implementing advanced control strategies. In this chapter, the development of a CACC strategy using a proportional integral derivative (PID) and model predictive control (MPC) is described.

The controller design is based on a combination of constant distance (CD) and constant headway time (CHT) policies. V2V and vehicle-to- infrastructure (V2I) communications are collectively termed as V2X communication. There are two types of devices used in V2X communication: Vehicles are equipped with on-board units, and the infrastructure is equipped with road-side units. On-board units transmit the vehicle state information, and road-side units transmit data depending on the infrastructure at which they are installed (e.g., a road-side unit at an intersection transmits the traffic signal data). To ensure an acceptable quality of service in V2X communication, the wireless standard must support high-frequency and low-latency data exchange.

To demonstrate vehicular communication as realistically as possible, we have chosen NS3 for network simulations. It contains the model libraries for simulating wireless access for vehicular environments (WAVE) architecture. WAVE is a family of standards that allow secure V2X communication in a high-speed transportation environment. The platoon and surrounding traffic are modelled in VISSIM [6], with MATLAB being used to connect VISSIM and NS3. The simulation results indicate a stable performance of the controller in real-life traffic situations. The neighboring V2V equipped traffic effect is accounted to analyze the controller behavior. This will provide a good starting point for the automotive industry as well as academic researchers to build advanced controllers for truck platooning.