Network protocols for vehicle platoon control and management
Part 1 Introduction to vehicle platooning
Vehicle platooning is a promising application in the transportation industry to improve the safety, efficiency, and comfort for passengers with innovative capabilities.
1.1 How Vehicle Platooning Works
Vehicle platooning is a convoy of vehicles with a lead vehicle driven with a professional driver and other vehicles closely followed. [pic]
The main goals of vehicle platooning are: (1) efficient transport such as increase the vehicle density on the highway (2) safe transport using various techniques such as obstacle detection, adaptive cruise control and avoidance, automatic car parking.
Most vehicle platooning systems are built on a linear configuration. The vehicles in the platoon will move following the action of the lead vehicle. Each vehicle has to coordinate its direction, speed and distance with the vehicle in front. All the vehicles in the platoon are relative independent and can move out the platoon. The driver of the vehicles in the platoon can relax as most driving is done by the professional driver in the lead vehicle . 1. 1. 1 Vehicle Control
Longitudinal control and lateral control is the most two important problems related to the control of the vehicle platooning systems .
Longitudinal control is actually to control the speed of vehicles and the distance between the vehicles in the platoon. The longitudinal control will maintain a stable distance between the front vehicle and the following vehicle with a couple of inches more or less. The speed, acceleration, and deceleration of the vehicles will be programmed in advance according to the speed limits as well as maximum acceleration and deceleration rate based on the road geometry. The longitudinal control is maintained by radio communication and radar among the vehicles. The velocity and separation is constantly updated and monitored .
Lateral control is to align the following vehicle’s direction similar to the front vehicle. It uses magnetic sensors and markers to set the position of the vehicle. The on-board computers process the data of the vehicle’s route and transfer the command to the brakes and actuators to keep right direction .
1.1. 2 Vehicle Management
The vehicle platoon system should enable the vehicles join and leave the platoon in route.
The vehicle platoon system creates a common travel plan with same travel route for the vehicles in the platoon. The platoons is set up with a couple of known vehicles and set a lead vehicle in the platoon. Common travel plans can be developed during the travel when a new platoon is set up. When a vehicle is going to join or leaving the platoon, the communication system will coordinate the maneuvers among the platoon .
If the vehicle in the platoon want to leave the platoon, it will inform the lead vehicle, the lead vehicle will analysis the route situation then decide whether gives the leave permission. If the vehicle is given leave permission, it will drop back to a long distance from the front vehicle together with the vehicles following it, then it drives away from the platoon. The vehicles following it will catch up with the front. The lead vehicle will analysis the new platoon and renews the setting of the platoon such as speed and distance. If the vehicle is going to join the platoon, it needs to send its own travel plan to the lead vehicle of the platoon. The lead vehicle will analysis the travel plan and decides whether gives the join permission. When given the join permission, the lead vehicle will generate where to insert vehicle in the platoon. The vehicles which will behind the joining vehicle will drop back to a long distance from the front vehicle. Then the new vehicle joins in the platoon. The lead vehicle renews the settings of the platoon as well as the common travel plan .
2. Advantages of Vehicle Platooning
1. 2. 1 Great fuel efficiency...
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