Manabu Omae

VEHICLE FOLLOWING CONTROL IN LATERAL DIRECTION FOR PLATOONING

Abstract Simulation and experimental study on lateral control for autonomous driving is presented in this paper. The objective of the lateral control system is to make the controlled vehicle follow the preceding vehicle. Simulation study is conducted for investigating the relationship between information for lateral control and the tracking accuracy obtained based on the information. Simulation results of vehicle-following control based on five kinds of control algorithms, each of which is designed using some information for lateral control, are compared and discussed. Experimental study is carried out by use of two vehicles to validate results of the simulation study. By both studies, it is clarified that side slip angle is the essential information for implementing an accurate vehicle-following control.

The Application of RTK-GPS and Steer-By-Wire Technology to the Automatic Driving of Vehicles and an Evaluation of Driver Behavior

Automatic vehicle driving has long been the subject of research efforts designed to improve the safety and efficiency of automobile transportation. In recent years, increasingly sophisticated sensors and automobiles have brought automatic driving systems closer to reality. In this paper we describe an attempt to apply real-time kinematic GPS (RTK-GPS), a highly precise positioning system, and steer-by-wire body technology, which has advanced greatly in recent years, to automatic driving. In addition, we also describe the results of research into human factors related to automatic driving, which will become more and more important as automatic driving is put to practical use.(A)

DGPS-based position measurement and steering control for automatic driving

Simulation and experimental studies are carried out for investigating the possibility of automatic vehicle control system based on absolute position information. Implementation of such control system requires a methodology of measuring the absolute position, and a control algorithm. In this paper, an accurate and real-time estimation of the absolute position by use of DGPS (Differential Global Positioning System) and sensors on a controlled vehicle is proposed. A steering control algorithm for tracking the desired course stored as absolute position data is also proposed. Simulation and experimental results validates the proposed estimation and control system, and provides the perspective of enhancing the automatic driving control system by use of the absolute position information.

Automatic Driving Control for Passing through Intersection without Stopping

A control method for passing through an intersection for automated vehicles is proposed. If automated vehicles approaching an intersection communicate with each other and schedule the time of entering the intersection by small deceleration and acceleration, the vehicles can pass the through the intersection without stopping thereby enabling energy-saving by reducing unnecessary deceleration. This study proposes a method of categorizing intersection patterns, and extracting the required conditions for the realization of a non-stop intersection for each intersection pattern, performing control to realize such an intersection and transmitting information to vehicles entering the intersection for the creation of a virtual platoon. The proposed method is validated by experiments at an intersection of one-way traffic in single lanes.

GPS-BASED AUTOMATIC DRIVING CONTROL IN LOCAL AREA WITH COURSE OF LARGE CURVATURE AND PARKING SPACE

Vehicle motion control algorithms for fully automatic driving in a local area are proposed and investigated in this paper. Current automotive technologies for automatic driving have encountered the problems of system reliability, human factors and responsibility of accident. A fully automatic driving system, however, can be realized relatively easily as long as it is operated in a local area such as a campus or a site of an institute. This study is aiming at investigating human factors, system reliability and methodology of system management by operating a fully automatic driving system in the campus. In this paper, experimental studies are carried out for developing such a fully automatic driving system using a precise GPS. Two control algorithms for automatic driving in a local area is proposed. One is control algorithm for tracking a trajectory with small radius of curvature, and the other is that for automatic parking. Experimental results clarified that a controlled vehicle can track a trajectory with curvature of more than 0.2, and can accurately park in a parking space with reverse movement by the proposed control algorithms.

Control Procedures and Exchanged Information for Cooperative Adaptive Cruise Control of Heavy-Duty Vehicles Using Broadcast Inter-Vehicle Communication

The Cooperative Adaptive Cruise Control system (CACC) is an enhancement of the Adaptive Cruise Control system (ACC) that uses inter-vehicle communication to realize safe cruising at shorter inter-vehicle distance. To effectively communicate via broadcasting, a vehicle must identify the ID of the preceding vehicle, and extract that vehicle’s information from the information sent by surrounding vehicles. In addition, the vehicle should ideally be able to reference information from other members of the platoon. In this manner, the system can evolve towards platooning with a very short inter-vehicle distance. On the other hand, if CACC is to acquire the same flexibility as ACC, the vehicle should handle common driving maneuvers such as lane-change of the preceding vehicle, cut-in of vehicles, and change of control mode of the preceding vehicle. Given the above requirements, this paper proposes control procedures and inter-vehicle communication schemes for implementing CACC of heavy-duty vehicles developed as part of the NEDO’s Development of Energy-Saving ITS Technologies project.

Spacing control of cooperative adaptive cruise control for heavy-duty vehicles

Abstract This study proposes a spacing control algorithm for the Adaptive Cruise Control system (ACC) using inter-vehicle communication. An important consideration in ACC controller design is string stability, which should be guaranteed in the control algorithm; that is, the amplitudes of the spacing vibration should not become amplified as they propagate upstream from vehicle to vehicle. When the controller uses inter-vehicle distance and relative velocity information, heavy-duty vehicles may lose string stability under short time-headway control on account of their slow-response acceleration characteristics. For example, the limiting headway time of a heavy-duty vehicle (with time constant of acceleration response 0.5 s) is 1 s. Under limiting conditions, spacing vibrations and acceleration vibrations are neither amplified nor attenuated. As an energy saving technique, our algorithm effectively attenuates acceleration vibrations under the limiting conditions of ACC by spacing control using information obtained by inter-vehicle communication. The proposed controller is validated by simulations.

State Observation and Communication for Cloud Vehicle Control

In this study, a new method was developed to automate vehicles. Numerous vehicle control systems have been realized for electronic steering, driving, and braking. Higher-standard vehicle control systems have increased costs. This study focused on cloud vehicle control using roadside sensors and computers. If a high-standard vehicle control system can be realized by using vehicles with no sensors or computers, this can create a new service model for transport. The key point was to obtain state quantities of vehicles and to maintain vehicle-to-roadside communication. The proposed method obtains state quantities of vehicles with roadside sensors by using the iterative closest point algorithm. The vehicle positions are correlated with communication information. The control quantities of the vehicles are received by roadside computers. Experiments using electric vehicles showed that the proposed method can realize high-standard vehicle control for self-driving vehicles.

Flexible and Energy-Saving Platooning Control Using a Two-Layer Controller

This paper proposes a method for controlling the behavior of vehicles with respect to platooning techniques such as forming and splitting a platoon and switching lateral control between vehicle-following mode and road-following mode. The proposed control architecture comprises two layers: a status-control layer and a motion-control layer. This two-layer control architecture improves the behavior of individual vehicles and the platoon as a whole without increasing the complexity of the system. Moreover, the proposed control method allows for the formation of a platoon in accordance with a rule designed to promote energy-saving maneuvering at the time of the platoon’s formation. The proposed control method is validated by conducting experiments using small electric vehicles.

Extraction of Urban Morphological Properties from Airborne LIDAR Dataset and their Implications

Emergence of new sensing technologies gives rise to new types of information. Light Detection And Ranging (LIDAR) is one of such Technologies. It enables measurements of altitudes of sampled points on ground objects as well as on the ground, and consequently, generation of surface models. Extraction of morphological properties from such a model is possible, and combinations of such parameters lead to implications. By applying this to an urban area, a surface model only representing morphology of buildings could become a matrix to derive socio-economic implications. In this context, a set of experiments were conducted by using a part of central Tokyo as a study site.