Vehicle control method and system for use in automatic driving system

Abstract: A vehicle control method for use in an automatic driving system which transmits drive support information stored in each of markers (12) buried in a road (11) at regular intervals, to a vehicle (6) which passes the marker (12), in order to support driving of the vehicle (6), characterized by comprising the steps of storing, in the marker (12), positional information (24) indicative of the position of the marker (12), and at least one of road information (25) indicative of the state of the road (11) and control information (26) concerning the speed and traveling direction of the vehicle (6), and transmitting, to the vehicle (6), the positional information (24) and the at least one of the road information (25) and the control information (26), which are used as the driving support information.

Description: This invention relates to a vehicle control method and system for use in an automatic driving system. To realize an automatic vehicle driving system, it is important to detect the position or speed of the vehicle. In the conventional art, the vehicle position or speed is detected by means for directly converting the rotational speed of a wheel of the vehicle into a pulse signal to calculate the vehicle speed or the travelled distance, or means including a GPS (global positioning system) for determining the vehicle position using an artificial satellite, or means for transmitting absolute positional information stored in a marker buried in the ground, using transmission means such as a radio installation. FIG. 1 is a conceptual view, useful in explaining the conventional automatic driving system, and showing a junction area on a highway 1. A minor road 3 meets a major road 2 at the junction. Markers 4 are buried at regular intervals along the center line of each of the major road 2 and the minor road 3. Each marker 4 stores information concerning its location, and is disposed to transmit the information to a position above the road by, for example, radio. Further, monitoring cameras 5 are provided at regular intervals at the side of the highway 1. A vehicle 6 which travels on the road has a communication device 16 on its bottom for receiving positional information from the markers 4, and an antenna 7 on its top for receiving a GPS radio wave from an artificial satellite 8. The vehicle 6 also has, if necessary, a measuring device 30 for measuring the vehicle speed, the travelled distance, etc. by converting the rotational speed of a wheel of the vehicle into pulses and counting them. The vehicle 6 further has a controller 31 including a computer installed in the vehicle. The positional information transmitted from the marker 4 and received by the communication device 16, the information transmitted from the artificial satellite 8 and received by the antenna 7, and the vehicle speed and the travelled distance measured by the measuring device 30 are input to the vehicle controller 31, which in turn drives the vehicle 6 based on the input information. However, the conventional method for measuring the vehicle speed and travelled distance from the pulses indicative of the rotational speed of a wheel of the vehicle 6, and controlling the vehicle based on the measurement values is considered mere auxiliary means. This is because a slip may well occur between the road and the wheels of the vehicles when the vehicle speed abruptly changes or the surface of the road becomes less suitable for driving, which makes it difficult to accurately measure the vehicle speed or travelled distance. Moreover, although the vehicle control method using the GPS and the artificial satellite 8 is effective for wide-range positioning, it cannot be used in a tunnel or between tall buildings yet. Therefore, this method cannot singly establish an automatic driving system and hence is only used as auxiliary means. In addition, the conventional vehicle control method using the marker 4 is used at a branchpoint or a junction of a highway as shown in FIG. 1, at which information indicative of the accurate speed of the vehicle 6 is required. Since the marker 4 stores only fixed information concerning the position of the marker-installed position, it is not used at any place other than the branchpoint or the junction. In other words, the conventional vehicle control method using the marker 4 can be used only for limited purposes. Even when this method is used on a road other than at a branchpoint or a junction, it imparts only positional information to a traveling vehicle, and accordingly contributes neither to automatic driving control of the vehicle, nor to the maintenance of the road. In EP O 618 557 A1 is a vehicle control method for use in an automatic driving system disclosed, which transmits drive support information stored in each of the markers varied in a road at regular intervals to a vehicle, which passes the marker in order to support driving of the vehicle. The vehicle control method comprises the steps of storing, in the marker, positional information indicative of the position of the marker, and at least one of road information indicative of the state of the road and control information concerning the speed and traveling direction of the vehicle, and transmitting to the vehicle, the positional information and at least one of the road information and the control information, which are used as a driving support information. The transponders are provided for controlling individual vehicles. However, no count of the number of vehicles passing the marker is available in the method and nor maintenance information is provided. It is the object of the invention to provide a vehicle control method and system for use in an automatic driving system, capable of supporting automatic drive of a traveling vehicle using markers, and obtaining information for the maintenance of a road from the markers. To attain the object, there is provided a vehicle control method for use in an automatic driving system which transmits drive support information stored in each of markers buried in a road at regular intervals, to a vehicle which passes the marker, in order to support driving of the vehicle, comprising the steps of: counting, in the marker, the number of vehicles which pass the marker, obtaining information indicative of abnormality and failure of the marker itself; storing, in the marker, positional information indicative of the position of the marker, and at least one of road information indicative of the state of the road and control information concerning the speed and traveling direction of the vehicle, and also storing information indicative of the counted number and the information indicative of the abnormality and failure as maintenance information; and transmitting, to the vehicle, the positional information and the at least one of the road information and the control information, which are used as the driving support information, and also transmitting the maintenance information. In the invention, each marker transmits, to a traveling vehicle, positional information and at least one of the road information and the control information, which are used as drive support information. As a result, the automatic drive of the vehicle is supported by the drive support information not only at a branchpoint/junction but also at other points on the road. This invention can be more fully understood from the following detailed description when taken in conjunction with the accompanying drawings, in which: FIG. 1 is a conceptual view, showing the conventional automatic driving system; FIG. 2 is a view, showing a marker section incorporated in an automatic driving system according to an embodiment of the invention; and FIG. 3 is a view, showing information stored in the marker section in the embodiment. The embodiment of the invention will be described with reference to the accompanying drawings. FIG. 2 is a view, showing a vehicle and a marker section incorporated in an automatic driving system according to the invention. As is shown in FIG. 2, markers 12 are buried at regular intervals in center portions of a road 11 on which a vehicle 6 travels. Each marker 12 comprises a communication section 13, a processing section 14, a storage section 15 and a power supply section 32. AC power is supplied to the power supply section 32 from a power supply line 33 located, for example, along the road 11. The power supply section 32 rectifies AC power, and supplies a DC voltage as an operation voltage to the communication section 13, the processing section 14 and the storage section 15. As is shown in FIG. 3, the storage section 15 includes a fixed information storage 21 consisting of, for example, an EEPROM storing information which does not need changing, and a variable information storage 22 consisting of, for example, a RAM storing information which needs changing. Specifically, the fixed information storage 21 stores marker information 23 such as the identification number or installation date of the marker set in or outside the vehicle when the marker is buried; positional information 24 including information concerning the coordinates of the absolute position of the marker itself and information concerning the position of the marker relative to another one or the distance therebetween; road information 25 which includes information concerning the inclination, curvature, etc. of the road 11 and road surface information concerning the friction factor, shape, etc. of the road surface; and control information 26 which includes acceleration/deceleration instructing information for instructing the vehicle to accelerate, decelerate, stop, etc., and steering instructing information for instructing the traveling direction of the vehicle. The variable information storage 22 stores maintenance information 27 which includes information concerning the number of vehicles having passed the marker, and information concerning abnormality, failure, etc. of the marker itself. The vehicle 6 has a communication device 16 provided on its bottom such that it is opposed to the surface of the road, and a computer 17 provided therein as a vehicle controller. The computer 17 automatically controls the traveling of the vehicle 6 on the basis of information transmitted from the marker 12 and received by the communication device 16. When in the above-described structure, the vehicle 6 passes the marker 12, the fixed information is read by the processing section 14 from the fixed information storage 21 incorporated in the storage section 15 of the marker 12, and transmitted to the communication device 16 via the communication section 13 by, for example, radio transmission. At this time, the processing section 14 reads the fixed information stored in the fixed information storage 21 in response to an instruction to read output from, for example, the vehicle computer 17 via the communication device 16. The vehicle computer 17 controls the traveling of the vehicle 6 on the basis of information transmitted from the marker 12 and received by the communication device 16. More specifically, the computer 17 controls the traveling of the vehicle 6 by supplying a drive unit 6A with the fixed information transmitted from the marker 12 and received by the communication device 16, i.e. the positional information 24, the road information 25, and the control information 26. Although the vehicle computer 17 performs traveling control of the vehicle 6 mainly based on the positional information 24 and the control information 26, it can also anticipate a change in the state of the road ahead on the basis of the road information 25 which includes information concerning the inclination or curvature of the road 11, and/or road surface information concerning the friction factor or configuration of the road surface. As a result, the traveling control of the vehicle can be performed smoothly. On the marker 12 side, the processing section 14 calculates the number of occasions of communication between itself and vehicles 6 having passed it, and writes, into the variable information storage 22, the number of occasions of communication as the number of vehicles having passed it. Moreover, the marker 12 inspects itself using the processing section 14, and writes, into the variable information storage 22, information which indicates abnormality or failure of itself, if any, and is used as the maintenance information 27. The information indicative of the number of passing vehicles and the information indicative of marker abnormality/failure can be obtained by periodically reading the information stored in the variable information storage 22 of the storage section 15, using, for example, an inspection car which travels along the road. From the inspected road surface conditions of each marker-buried point, whether or not the road needs maintenance work, or when the road should be repaired can be accurately estimated. The inspection car is basically equipped with the communication device 16 and the computer 17 as in the case of the vehicle 6 shown in FIG. 2. When the inspection car passes the marker 12, the computer 17 transmits, via the communication device 16, an instruction to read maintenance information. When the marker 12 has received the maintenance information, the processing section 14 reads the maintenance information 27 from the variable information storage 22, as well as the fixed information such as the marker information 23, the positional information 24, the road information 25, the control information 26 which are stored in the fixed information storage 21, thereby transmitting the information to the vehicle 6 via the communication section 13. Then, the computer 17 in the vehicle stores, in a storage 34 incorporated therein, the marker information 23 and the maintenance information 27 transmitted from the marker 12. As described above, the inspection car collects the maintenance information 27 of each marker 12 while traveling along the road 11. From the collected marker information 23, maintenance information 27, etc., the state of the road surface at the installation point of the marker can be determined, thereby precisely estimating if or when road maintenance work is or will be necessary. As described in detail, in the invention, markers buried in a road at regular intervals each have a storage which stores marker positional information, road information including road inclination information, road curvature information, road-surface information, etc., and control information including speed instructing information, acceleration/deceleration instructing information, steering instructing information, etc., thereby transmitting, to each vehicle which passes the marker, the road information and control information as well as the marker positional information. As a result, the invention can support automatic drive not only at a branchpoint or a junction but also at other points on the road. In addition, in the invention, the marker has a function for counting the number of vehicles which pass it, and a self-inspecting function, and the counted number of vehicles and information concerning failure or abnormality of the marker obtained as a result of self-inspection are stored in a storage and used as maintenance information. An inspection car, for example, can detect the state of the road surface at the marker installation point by periodically reading the maintenance information, which greatly contributes to estimation as to if or when road maintenance work is or will be necessary.

Claims: A vehicle control method for use in an automatic driving system which transmits drive support information stored in each of markers (12) buried in a road (11) at regular intervals, to a vehicle (6) which passes the marker (12), in order to support driving of the vehicle (6), characterized by comprising the steps of: counting, in the marker (12), the number of vehicles (6) which pass the marker (12), obtaining, in the marker (12), information indicative of abnormality and failure of the marker (12) itself, storing, in the marker (12), positional information indicative of the position of the marker (12), and at least one of road information (25) indicative of the state of the road (11) and control information (26) concerning the speed and traveling direction of the vehicle (6); and also storing information indicative of the counted number and the information indicative of the abnormality and failure as maintenance information (27); and transmitting, to the vehicle (6), the positional information (24) and the at least one of the road information (25) and the control information (26), which are used as the driving support information, and also transmitting the maintenance information (27). A method according to claim 1, characterized in that the road information (25) includes at least information indicative of the inclination, the curvature and the surface state of the road. A method according to claim 1, characterized in that the control information (26) includes at least speed instructing information, acceleration/deceleration instructing information and steering instructing information. An automatic driving system for transmitting drive support information stored in each of markers (12) buried in a road (11) at regular intervals, to a vehicle (6) which passes the marker, in order to support driving of the vehicle (6), characterized in that the marker (12) includes a processing section (14) for counting the number of vehicles (6) which pass the marker (12), and obtaining information (27) indicative of abnormality and failure of the marker (12) itself, and storage means (15) which stores positional information (24) indicative of the position of the marker and at least one of road information (25) indicative of the state of the road and control information (26) concerning the speed and traveling direction of the vehicle (6), and also stores information indicative of the counted number and the information indicative of the abnormality and failure as maintenance information (27); the marker (12) also includes communication means (13) for transmitting, to the vehicle (6), the positional information (24) and the at least one of the road information (25) and the control information (26), which are used as the driving support information, and further transmitting, to the vehicle (6), the maintenance information (27) stored in the storage means (15). An automatic driving system according to claim 4, wherein the road information (25) includes at least information indicative of the inclination, the curvature and the surface state of the road. An automatic driving system according to claim 4, wherein the control information (26) includes at least speed instructing information, acceleration/deceleration instructing information and steering instructing information.

Inventors: HIGASHI SHINICHI, SUZUKI HIROSHI, TAKAGI AKIRA, HIGASHI, SHINICHI, SUZUKI, HIROSHI, TAKAGI, AKIRA
Applicants: MITSUBISHI HEAVY IND LTD, MITSUBISHI HEAVY INDUSTRIES, LTD.
Application year: 1997
Main classification: G08G1
IPC codes: B60W30, G08G1, G05D1