Tatsuhiro TAMAKI’s research while affiliated with National Institute of Technology Okinawa College and other places

According to a survey by the Ministry of Land, Infrastructure, Transport and Tourism, as much as 40% of the annual travel time is wasted in traffic jams. In addition, some studies have shown that the gas emitted by idling causes air pollution, and this has become a major social problem. One of the efforts to improve these problems caused by traffic congestion is the research on platooning. Most of the conventional research assumes a straight road as the experimental condition, and there is no discussion on the behavior at intersections scattered in the general roadway. In this study, a velocity control model is studied to avoid collisions with pedestrians when platoon vehicles make a turn at the intersection. A vehicle following model is defined according to Helly model which controls the vehicle acceleration according to relative speed and distance with the vehicle in front. The validity of the model is discussed from the computer simulation. Simulations were performed in some cases. The model could control the vehicles individually without collisions with pedestrians. However, these experiments were conducted only in an ideal environment by simulation. Therefore, in the future, the effectiveness of the model should be improved in actual traffic flow by conducting experiments using real vehicles.

Recently, traffic congestion has become a serious social problem all over the world as the number of vehicles increases. Traffic congestion causes economic loss, air pollution and traffic accident. For solving this problem, study on vehicle platooning using the technology of inter-vehicle communication has been studied widely. The vehicle platoon is a technique of grouping vehicles with a short inter-vehicle distance with help of electric and mechanical control, which is expected to reduce traffic congestion, and save labor and energy. However, when realizing platooning in the real world, the adequate control algorithm of the velocity of the vehicles in the platoon is necessary. In this study, the traffic situation is assumed so that the vehicles in the platoon and the other ones are travelling on the road. The vehicles in the platoon can keep their distance short by the help of inter-vehicle communication. The purpose of this study is to control the vehicle platoon safely without causing collision between vehicles when the sudden deceleration of the general vehicle in the platoon. The simulation and the experimental results showed that the proposal algorithms could control the vehicles without collision with the other vehicles and running backwards, while maintaining control of the velocity of the vehicles in the platoon.

In this study, the velocity control models of self-driving vehicles in vehicle platoons are studied when two platoons of two vehicles merge to one platoon. The velocity control is defined by means of the vehicle following models including vehicle-to-vehicle distance and the velocity differences. The model parameters are designed to minimize the three types of objective functions. Three objective functions are summarized as follows; the first is related to the overshoot of velocity, the second is to the vehicle-to-vehicle distance and the third is to the vehicle-to-vehicle distance and the acceleration. The effectiveness of models is compared in the experiment of LEGO MINDSTORM EV3. The results show that the objective function related to the velocity suppresses the excess amount of velocity and tends to be slow response, and that the objective function related to vehicle-to-vehicle distance produces a large excess amount and, however, shows a quick response result. Therefore, the parameters determined from the second and the third objective functions are better than that from the first one.

The platooning of vehicles is a very important technique for enhancing the traffic capacity without additional road network and improving the traffic safety. In the platooning, vehicles travel in the row so as to keep the vehicle head distance short. The most important thing from the existing studies is to realize the stable platooning of vehicles. On the other hand, our research group focuses on the control of the platooning of vehicles in several use cases such as junction and intersection. In this paper, the control of the platooning of vehicles in the intersection or crossover point is studied. The simulation region is the intersection of two straight roads. Two groups of two vehicles travel on different roads and meet at the intersection. The velocity of the vehicles is controlled by the vehicle following model. The model parameters are first designed in the computer simulation. The validity of the velocity and the behavior control models are discussed in the experiment of LEGO Mindstorm. The results show that the model can control the vehicles in the platoons safely.

In the vehicle platoon, vehicles move in the small distance. It can improve the traffic capacity of the traffic road network. For the safety traffic flow in the vehicle platoon, the vehicles are controlled with electric and mechanical systems. This study focuses on the simulation where vehicles in the platoon overtake the other vehicle. The vehicle velocity is controlled with the vehicle following model such as Chandler model, extended Chandler model and Asahina model. The model is confirmed in the simulation of three-vehicle platoon overtaking a vehicles. The results show that the extended Chandler model can control the vehicle platoon stably.

Vehicle platoon is very important techniques for increasing the traffic flow safely and effectively. The electric and mechanical systems are necessary for effective vehicle platoon. Several systems have been studied for control vehicles in the platoon. This paper focuses on the velocity control of the vehicles separating from the vehicle platoon. The velocity control model is defined according to the vehicle following model and then, the parameters are determined by minimizing the objective function. The model with the optimized parameters is applied for the vehicle platoon experiment of LEGO Mindstorms NXT. The experimental results are compared with the simulation results in order to confirm the validity of the model. Although the experimental results finally converge to the simulation results, there exists the difference between the computational simulation and the experimental results because of the error of the sensor and the others.

Grammatical Evolution (GE), which is one of Evolutionary Computations (EC), is designed to find function or program satisfying the design objective. The candidate solutions are defined as the binary bit-strings. The genotype (bit-string) is translated into the phenotype such as function or program according to the translation rule which is defined in Backus Naur Form (BNF). The aim of this study is to apply GE to the design of LEGO Mindstorms EV3 control program. The designed program applied to the robot in real world after adjusting control parameters for bridging the gap between simulator and real world. As a result, the behavior in real world was roughly equivalent to in simulator.

Vehicle platoon is the important technique for overcoming the traffic congestion and increasing the traffic capacity safely. When the vehicle platoon is used widely for the city traffic flow, the merging and the splitting of the vehicle platoons should be considered. Our research group focuses on vehicle following model for controlling the vehicle velocity in the vehicle platoon. The aim of this study is to discuss the effectiveness of multiple vehicle following models in the split behavior of six vehicles by simulation and machine experiment with LEGO MINDSTORMS NXT.

Vehicle Platoon is the important technique for increasing the traffic amount safely. Our research group focuses on the velocity control model of the vehicle in the vehicle platoon. Consider face-to-face traffic of one lane on one side when there are vehicle platoon running and independent vehicle running. In this study ,we will describe that a row running vehicle will overtake a vehicle in front while avoiding an oncoming lane vehicle.