Patent Description:
There is a great demand about mining sites for causing haulage vehicles to autonomously travel due to an increase in labor costs, and requests for enhancement of the safety. To meet this demand, there are known technologies in which haulage vehicles that haul earth/sand or mineral at mining sites are caused to autonomously travel according to instructions from a control server or the like, not depending on human driving.

For example, Patent Document <NUM> discloses a technology in which inter-vehicle positional data is transmitted to monitor mutual positional relations, and in a case where vehicles have approached each other too much, the vehicles are decelerated or stopped to avoid interference.

In addition, Patent Document <NUM> discloses a technology in which an emergency stop signal is transmitted to all haulage vehicles travelling in a mining site only when an emergency stop input apparatus is operated for a haulage vehicle travelling in the mining site.

In addition, Patent Document <NUM> discloses a vehicle interference avoidance technology in which the range of presence of a vehicle taking into consideration a length of time required for measuring the position of the vehicle is determined to thereby enable a safe prediction of the position of the vehicle even in a case where the frequency of wireless communication is low, and enable avoidance of interference between unmanned vehicles or manned vehicles in the entire area of a large work site. Additionally, Patent Document <NUM> describes a safety device for a vehicle traveling system that allows manned and unmanned vehicles to travel together. The system ensures safety by detecting abnormalities in safety devices mounted on manned vehicles. When an abnormality is detected, the system prohibits the manned vehicle from traveling, thereby preventing unexpected interference between manned and unmanned vehicles, especially in large-scale work sites where separating travel areas is impractical.

However, if haulage vehicles are decelerated or stopped frequently, the haulage efficiency lowers, leading to a lower productivity of the mining work at a mine. Because of this, there is a demand for a technology to decelerate or stop haulage vehicles only when needed.

Taking safety into consideration, also a functionality to transmit and receive inter-vehicle positional data, monitor mutual positional relations, and ensure the safety by decelerating vehicles in a case where the vehicles have approached each other is necessary. In that case, there is a demand, from the perspective of maintaining the productivity of the mining work at a mine, for increasing the speed after the deceleration as much as possible or for shortening the deceleration time as much as possible while ensuring the safety.

However, it is difficult, with the technologies disclosed in Patent Document <NUM>, Patent Document <NUM>, and Patent Document <NUM> described above, to ensure the safety and enhance the productivity at the same time.

The present invention has been made in view of the problem described above, and an object of the present invention is to provide a vehicle control system that makes it possible to ensure the safety and enhance the productivity at the same time.

Preferable embodiments are defined in the dependent claims.

The present specification makes reference the content disclosed by <CIT>, which forms the basis of the priority of the present application.

According to the vehicle control system of the present invention, it becomes possible to reduce unnecessary decelerations of an autonomous travel vehicle while maintaining the safety in a case where the autonomous travel vehicle and a manned vehicle have approached each other, and it becomes possible to enhance the safety and enhance the productivity at the same time.

An embodiment is explained below in detail on the basis of the diagrams. Note that in all the diagrams for explaining the embodiment, members having an identical functionality are given the same or related reference characters, and repetitive explanations thereof are omitted in some cases. In addition, in the following embodiment, explanations of the same or similar portions are not repeated in principle, except when they are particularly necessary.

The explanation of the following embodiment is divided into a plurality of sections or embodiments when it is necessary to do so for convenience. In a case where quantities or the like related to an element (including the number of the element, a numerical value related to the element, the amount of the element, a range related to the element, and so on) are mentioned in the following embodiment, the quantities are not limited to particular numbers unless clearly noted otherwise particularly, except when those quantities are obviously limited to the particular numbers in principle, and so on, and the quantities may be equal to or greater than or equal to or smaller than the particular numbers. Note that constituent elements (including processing steps and the like) of the following embodiment are not necessarily essential unless clearly noted otherwise particularly, except when those constituent elements are obviously essential in principle, and so on.

A vehicle control system according to a first embodiment of the present invention is explained below in detail with reference to diagrams. <FIG> is a schematic diagram depicting an example of overall configuration of a vehicle control system <NUM> of the first embodiment. The vehicle control system <NUM> functions also as an emergency stop system that stops autonomous travel vehicles at a time of emergency.

In <FIG>, the vehicle control system <NUM> includes: mobile transmitting terminals <NUM>-<NUM> to <NUM>-<NUM>; vehicle-mounted transmitting terminals <NUM>-<NUM> to <NUM>-<NUM>; vehicle-mounted receiving terminals <NUM>-<NUM> to <NUM>-<NUM>; relay base stations <NUM>-<NUM> to <NUM>-<NUM>; a central-control base station <NUM>; autonomous travel vehicles (hereinafter called "unmanned dumps") <NUM>-<NUM> to <NUM>-<NUM>; manned vehicles <NUM>-<NUM> to <NUM>-<NUM> that are driven by humans; and a control center <NUM>.

For example, the vehicle control system <NUM> is installed at a mine. The unmanned dumps <NUM>-<NUM> to <NUM>-<NUM> are vehicles that can travel autonomously in an unmanned state. For example, the unmanned dumps <NUM>-<NUM> to <NUM>-<NUM> are used as haulage vehicles that haul earth/sand or mining objects for the purpose of hauling a load such as earth/sand or ore. In addition, an operation management system <NUM> and an emergency stop input apparatus <NUM> are installed in the control center <NUM>.

Note that the number of each type of apparatus is not limited to a number depicted in the diagrams or to a particular number. For example, there may be only one vehicle-mounted receiving terminal and unmanned dump, or there may be a plurality of vehicle-mounted receiving terminals and/or unmanned dumps. In addition, there may be only one vehicle-mounted transmitting terminal and manned vehicle, or there may be a plurality of vehicle-mounted transmitting terminals and/or manned vehicles.

In addition, although not depicted, an autonomous travelling assisting system for autonomous travelling of the unmanned dumps <NUM>-<NUM> to <NUM>-<NUM> is provided at a work site in a mine.

All the mobile transmitting terminals <NUM>-<NUM> and <NUM>-<NUM> may have identical configuration or may each have different configuration. In the description below, the mobile transmitting terminals <NUM>-<NUM> and <NUM>-<NUM> are collectively referred to as "mobile transmitting terminals <NUM>" without making a distinction therebetween, in some cases. Similarly, the vehicle-mounted transmitting terminals <NUM>-<NUM> and <NUM>-<NUM>, the vehicle-mounted receiving terminals <NUM>-<NUM> to <NUM>-<NUM>, and the relay base stations <NUM>-<NUM> and <NUM>-<NUM> also are collectively referred to as "vehicle-mounted transmitting terminals <NUM>," "vehicle-mounted receiving terminals <NUM>," and "relay base stations <NUM>," respectively, in the description in some cases. In addition, since all the unmanned dumps <NUM>-<NUM> to <NUM>-<NUM> also may have identical configuration, they are described as "unmanned dumps <NUM>" in a case where they are collectively referred to, in some cases. The manned vehicles <NUM>-<NUM> and <NUM>-<NUM> also are collectively referred to as "manned vehicles <NUM>" in some cases.

An unmanned dump <NUM> is an autonomous travel vehicle configured to be capable of travelling in an unmanned state on the basis of control by the vehicle control system <NUM>, and is operated in principle without a driver getting on it. Note that, whereas controlled objects of the vehicle control system <NUM> are the unmanned dumps <NUM> in the present embodiment, autonomous travel vehicles which are controlled objects of the vehicle control system <NUM> are not limited to unmanned dumps, and manned dumps also may be controlled objects at the same time, and it is also possible to perform control similar to that for the unmanned dumps <NUM>.

In an unmanned state, the unmanned dumps <NUM> autonomously travel on roads <NUM> that are preset in a mining site. For example, excavators that perform work of loading earth/sand or ore are deployed at a loading site <NUM>, and the unmanned dumps <NUM> go back and forth between the excavators and a soil-dropping site <NUM> along the roads <NUM>, and haul the loads.

Note that at the mining site, the manned vehicles <NUM> also are travelling, in addition to the unmanned dumps <NUM> that haul loads such as earth/sand or ore. The manned vehicles <NUM> are vehicles that are configured such that drivers or other personnel can get on them, and are configured such that the drivers can perform driving operation of them. Examples of the manned vehicles <NUM> include excavators as mentioned above, bulldozers that level the road surfaces of the roads <NUM>, water-sprinkling vehicles, service cars that patrol the mining site, and the like.

A mobile transmitting terminal <NUM> is a mobile apparatus that can be carried by an operator in the mining site. The mobile transmitting terminal <NUM> has a functionality as an emergency stop apparatus that gives an instruction for emergently stopping an unmanned dump <NUM> at a time of emergency.

A vehicle-mounted transmitting terminal <NUM> is a vehicle-mounted apparatus mounted on a manned vehicle <NUM>. The vehicle-mounted transmitting terminal <NUM> also has a functionality as an emergency stop apparatus, and a driver or personnel on board the manned vehicle <NUM> can give an instruction for emergently stopping the unmanned dumps <NUM> by using the vehicle-mounted transmitting terminal <NUM> at a time of emergency.

The mobile transmitting terminals <NUM> and the vehicle-mounted transmitting terminals <NUM> can transmit emergency stop command signals. For example, the emergency stop command signals can be transmitted from the roads <NUM>, the loading site <NUM>, the soil-dropping site <NUM>, and the like in the site.

In addition, a vehicle-mounted receiving terminal <NUM> can directly or indirectly receive emergency stop command signals transmitted from the mobile transmitting terminals <NUM> or the vehicle-mounted transmitting terminals <NUM>.

Note that the definition of a "time of emergency" is not limited particularly in the present embodiment, and an operator or a driver of a manned vehicle <NUM> or the like can determine that it is a time of emergency as her/his decision. Typical criteria used for determining that it is a time of emergency are those related to general situations where it is necessary to stop an unmanned dump <NUM>, and, for example, the situations include a situation where there is a possibility of collision and/or interference between unmanned dumps <NUM> or between an unmanned dump <NUM> and a manned vehicle <NUM>, a situation where there is a possibility of collision and/or interference between an operator and an unmanned dump <NUM>, and the like.

The vehicle-mounted receiving terminals <NUM>-<NUM> to <NUM>-<NUM> are wireless receiving apparatuses mounted on the unmanned dumps <NUM>-<NUM> to <NUM>-<NUM>, respectively. The vehicle-mounted receiving terminals <NUM>-<NUM> to <NUM>-<NUM> can receive signals transmitted from the mobile transmitting terminals <NUM> or the vehicle-mounted transmitting terminals <NUM>. The signals include emergency stop command signals for stopping the unmanned dumps <NUM>-<NUM> to <NUM>-<NUM>.

Emergency stop command signals can also be directly received from the mobile transmitting terminals <NUM> or the vehicle-mounted transmitting terminals <NUM>, and emergency stop command signals can also be received by being relayed via the relay base stations <NUM> or the central-control base station <NUM>.

If the vehicle-mounted receiving terminals <NUM>-<NUM> to <NUM>-<NUM> receive emergency stop command signals, in response, the unmanned dumps <NUM>-<NUM> to <NUM>-<NUM> stop travelling. Installation locations of antennas of the vehicle-mounted receiving terminals <NUM> mounted on the unmanned dumps <NUM> are not limited to particular locations. As an example, the antennas can be installed at locations with good reception of radio waves, for example at front portions on the upper surfaces of the unmanned dumps <NUM>.

Each relay base station <NUM> or the central-control base station <NUM> is a wireless base station that relays communication related to the unmanned dumps <NUM> and the manned vehicles <NUM>. The position where each relay base station <NUM> or the central-control base station <NUM> is installed is determined such that wireless communication of the unmanned dumps <NUM> and the manned vehicles <NUM> becomes possible. For example, areas where there is a possibility that the unmanned dumps <NUM> or the manned vehicles <NUM> move include the roads <NUM>, the loading site <NUM>, the soil-dropping site <NUM>, and the like, and the position of each relay base station <NUM> or the central-control base station <NUM> is determined such that wireless communication of the unmanned dumps <NUM> and the manned vehicles <NUM> positioned in those areas becomes possible.

The relay base stations <NUM> are connected with each other by wireless lines. In addition, the relay base stations <NUM> and the central-control base station <NUM> also are connected with each other by wireless lines. The relay base stations <NUM> and the central-control base station <NUM> relay emergency stop command signals transmitted from the mobile transmitting terminals <NUM> and the vehicle-mounted transmitting terminals <NUM>, and thereby a command for emergently stopping all the unmanned dumps <NUM> in the mining site can be given.

In a case where an emergency stop command signal is given from any of the mobile transmitting terminals <NUM> and the vehicle-mounted transmitting terminals <NUM>, not only unmanned dumps <NUM> that are actually required to stop, but all the unmanned dumps <NUM> are stopped, in possible configuration.

In this manner, the mobile transmitting terminals <NUM> and the vehicle-mounted transmitting terminals <NUM> are terminals that can transmit emergency stop command signals as instructions for stopping the unmanned dumps <NUM>. The unmanned dumps <NUM> stop upon receiving the emergency stop command signals.

The emergency stop input apparatus <NUM> is installed in the control center <NUM>. The emergency stop input apparatus <NUM> and the central-control base station <NUM> are connected communicatively with each other by a cable line <NUM>. The emergency stop input apparatus <NUM> is an apparatus that gives an emergency stop command according to operation by an operator. An operator in the control center <NUM> can give an emergency stop command to all the unmanned dumps <NUM> through the central-control base station <NUM> by using the emergency stop input apparatus <NUM>. Note that whereas the emergency stop input apparatus <NUM> is explained as being connected with the central-control base station <NUM>, it may be connected not with the central-control base station <NUM>, but with a relay base station <NUM>, in other possible configuration. The emergency stop input apparatus <NUM> also is a terminal that can transmit an emergency stop command signal as an instruction for stopping the unmanned dumps <NUM>.

For example, the vehicle-mounted transmitting terminals <NUM> and the vehicle-mounted receiving terminals <NUM>-<NUM> to <NUM>-<NUM> have mounted thereon GPS receivers as means for acquiring information about their own positions. By using the GPS receivers, the manned vehicles <NUM> and the unmanned dumps <NUM> can acquire the information about their own positions.

A vehicle-mounted transmitting terminal <NUM> mounted on a manned vehicle <NUM> has a functionality of transmitting information about its own position. A vehicle-mounted receiving terminal <NUM> mounted on an unmanned dump <NUM> can determine a distance (inter-vehicle distance) between the unmanned dump <NUM> and each manned vehicle <NUM> by using positional information about the manned vehicle <NUM> sent from the manned vehicle <NUM>, and information about its own position acquired from a GPS receiver mounted on the unmanned dump <NUM>. Note that certainly there are no problems even if the method of acquiring information about its own position is a method that does not use a GPS.

<FIG> is a diagram depicting in detail a relation among wireless lines related to a mobile transmitting terminal <NUM>, a vehicle-mounted transmitting terminal <NUM>, a vehicle-mounted receiving terminal <NUM>, a relay base station <NUM>, the central-control base station <NUM>, an unmanned dump <NUM>, and a manned vehicle <NUM>.

Note that wireless lines set in this vehicle control system <NUM> are defined as follows in the explanation of the present embodiment.

<FIG> is a diagram depicting an example of a wireless frame and subframes used in the vehicle control system <NUM>. When a plurality of communication channels related to a plurality of wireless base stations and a plurality of wireless terminals are multiplexed, various multiplexing methods are adopted for avoiding mutual communication interference.

Known multiplexing methods for avoiding interference include: the CSMA-CA (Carrier Sense Multiple Access/Collision Avoidance) method using carrier-sense used in a Wi-Fi system or the like; and the time division multiplexing method called as TDMA (Time Division Multiple Access) in which a wireless frame is divided in advance into units called as subframes, and communication opportunities are given regularly. Note that, in a case where OFDM (Orthogonal Frequency Division Multiple) is adopted as a modulation method in addition to these, this means that orthogonal frequency division multiplexing called as OFDMA (Orthogonal Frequency Division Multiple Access) is used.

Typically, the CSMA-CA method has a problem that it becomes difficult to obtain communication opportunities if the numbers of wireless base stations and wireless terminals increase. Because of this, in a wireless system that places importance on safety, the time division multiplexing method in which opportunities for communication are given regularly is adopted often.

In subframe allocation <NUM> depicted in <FIG>, a wireless frame is divided at predetermined intervals according to the time division multiplexing method. For example, each wireless frame has a duration of one second. For example, in accordance with a plurality of communication channels, the wireless frame can be divided into a control communication subframe <NUM> for allocating control communication, an infrastructure-to-infrastructure communication subframe <NUM> for allocating the infrastructure-to-infrastructure communication <NUM>, an infrastructure-to-vehicle communication subframe <NUM> for allocating the infrastructure-to-vehicle communication <NUM>, a pedestrian-to-vehicle communication subframe <NUM> for allocating the pedestrian-to-vehicle communication <NUM>, a pedestrian-to-infrastructure communication subframe <NUM> for allocating the pedestrian-to-infrastructure communication <NUM>, and a vehicle-to-vehicle communication subframe <NUM> for allocating the vehicle-to-vehicle communication <NUM>.

The control communication includes communication for distributing notification parameters necessary for the mobile transmitting terminals <NUM>, the vehicle-mounted transmitting terminals <NUM>, the vehicle-mounted receiving terminals <NUM>, and the relay base stations <NUM> to start communication, and communication for going through a connection procedure necessary for starting mutual communication thereamong.

Note that although not depicted in <FIG>, intervals called as guard time for avoiding interference due to differences between propagation delays are actually provided between the subframes. In addition, in a case where the TDD (Time Division Duplex) method in which the same frequency is used for communication on an uplink and a downlink is adopted, the subframes can be divided into two for the downlink and the uplink. Instead of the TDD method, the FDD method (Frequency Division Duplex) in which different frequencies are used for communication on a downlink and an uplink can also be adopted.

Note that each of the mobile transmitting terminals <NUM>, the vehicle-mounted transmitting terminals <NUM>, the vehicle-mounted receiving terminals <NUM>, the relay base stations <NUM>, or the central-control base station <NUM> is allocated a subframe that is decided in advance depending on which it communicates with. Since a subframe is given for each wireless frame, in each wireless frame, each of the mobile transmitting terminals <NUM>, the vehicle-mounted transmitting terminals <NUM>, the vehicle-mounted receiving terminals <NUM>, the relay base stations <NUM>, or the central-control base station <NUM> is necessarily given a communication opportunity, and an emergency stop signal and positional information are exchanged.

In a case where there are a plurality of any of mobile transmitting terminals <NUM>, vehicle-mounted transmitting terminals <NUM>, vehicle-mounted receiving terminals <NUM>, and relay base stations <NUM>, a subframe may further be divided corresponding to each of the plurality of terminals or stations (or corresponding to each combination of them).

<FIG> is a diagram depicting an example of operation of approach detection and emergency stop in the vehicle control system <NUM> of the first embodiment. At the normal time, a manned vehicle <NUM> acquires information about its own position from the GPS receiver (not depicted) mounted on the vehicle-mounted transmitting terminal <NUM>.

The manned vehicle <NUM> uses a first communication line to transmit the information about its own position and an emergency stop signal to an unmanned dump <NUM>. For example, the first communication line is a communication line that goes through a wireless base station. In the present embodiment, it is a line that goes through infrastructure-to-vehicle communication <NUM>-<NUM>, the infrastructure-to-infrastructure communication <NUM>, and infrastructure-to-vehicle communication <NUM>-<NUM> in this order.

In addition, the manned vehicle <NUM> uses a second communication line to transmit the information about its own position and an emergency stop signal to an unmanned dump <NUM>. The second communication line is a line including communication paths different from those of the first communication line. For example, the second communication line is a communication line that does not go through a wireless base station, that is, a line that does not go through the infrastructure-to-vehicle communication <NUM> and the infrastructure-to-infrastructure communication <NUM>. In the present embodiment, the second communication line includes only the vehicle-to-vehicle communication <NUM>.

In this manner, the first communication line and the second communication line can be used in the time division multiplexing method. In that case, the first communication line and the second communication line can be used in mutually overlapping frequency bands, and this allows efficient use of communication bandwidths.

By preparing two types of communication line in this manner, it becomes possible to perform efficient communication according to the situation. For example, in a case where the unmanned dump <NUM> and the manned vehicle <NUM> have a positional relation that allows direct communication, they can communicate with each other at a high speed without using a communication line that goes through the infrastructure-to-vehicle communication <NUM> and the infrastructure-to-infrastructure communication <NUM>, and in a case where the unmanned dump <NUM> and the manned vehicle <NUM> have a positional relation that does not allow direct communication, they can use a wide area communication line that goes through the infrastructure-to-vehicle communication <NUM> and the infrastructure-to-infrastructure communication <NUM>.

On the other hand, the unmanned dump <NUM> uses the first communication line and the second communication line to receive the positional information about the manned vehicle <NUM>. In addition, the unmanned dump <NUM> acquires information about its own position (for example, similarly to the manned vehicle <NUM>). Then, the unmanned dump <NUM> determines an inter-vehicle distance X between the unmanned dump <NUM> and the manned vehicle <NUM> by using the information about its own position and the positional information about the manned vehicle <NUM>.

In this manner, the vehicle control system <NUM> includes a plurality of communication lines connecting the unmanned dumps <NUM> and the manned vehicles <NUM> with each other. Note that whereas both the first communication line and the second communication line are available in the state supposed in the description above, one or both of the communication lines is/are unavailable depending on the situation, in some possible cases.

As depicted in <FIG>, on the basis of the positional information about the manned vehicle <NUM> received by using the first communication line from the manned vehicle <NUM>, the unmanned dump <NUM> decides whether or not the inter-vehicle distance X to the manned vehicle <NUM> is equal to or shorter than a preset reference distance Y. The reference distance Y is a reference distance for detecting that the unmanned dump <NUM> and the manned vehicle <NUM> have approached each other, and in a case where the inter-vehicle distance X is equal to or shorter than the reference distance Y, it is decided that it is detected that the unmanned dump <NUM> and the manned vehicle <NUM> have approached each other.

In a case where the inter-vehicle distance X is equal to or shorter than the reference distance Y, the unmanned dump <NUM> decelerates to a preset travel speed for ensuring safety. Note that a method of determining the travel speed after the deceleration is mentioned later.

In the present specification, a "speed" is a value representing only a speed not including directional information, for example.

Here, a communication delay related to each communication line in <FIG> is defined as follows.

The total of communication delays in a case where positional information is transferred from a manned vehicle <NUM> to an unmanned dump <NUM> by using the first communication line is T1 + T2 + T2 + T3. This total value can be measured in advance, and stored on a storage apparatus of the unmanned dump <NUM> or the vehicle-mounted receiving terminal <NUM>.

On the other hand, a communication delay in a case where positional information is transferred from a manned vehicle <NUM> by using the second communication line (e.g. by using the vehicle-to-vehicle communication <NUM> for performing direct communication between an unmanned dump <NUM> and the manned vehicle <NUM>) includes only T4. This value can be measured in advance, and stored on a storage apparatus of the unmanned dump <NUM> or the vehicle-mounted receiving terminal <NUM>.

It is supposed in this example that the communication delay related to the second communication line is shorter than the communication delay related to the first communication line. That is, T4 < T1 + T2 + T2 + T3.

<FIG> is a schematic diagram depicting how it appears in a case where a manned vehicle <NUM> and an unmanned dump <NUM> have approached each other. <FIG> is a diagram about a time point at which the inter-vehicle distance X becomes equal to the reference distance Y. An area that has its center on the unmanned dump <NUM>, and has a radius which is equal to the reference distance Y is defined as a movable range <NUM>.

For example, the reference distance Y is computed in advance as such a distance that the unmanned dump <NUM> travelling toward the stopped manned vehicle <NUM> can stop safely if the unmanned dump <NUM> starts being braked when it is at the distance. In the present embodiment, the reference distance Y is computed according to the estimated sum of a braking distance, a free running distance and an error of positional information.

<FIG> depicts a breakdown of the reference distance Y corresponding to communication using each communication line. The unmanned dump <NUM> travels at a second speed V2 in a case where communication using only the first communication line is performed. That is, this is equivalent to a case where the second communication line is unavailable.

It is supposed that the unmanned dump <NUM> travels at a first speed V1 in a case where communication using the second communication line is possible.

The first speed V1 and the second speed V2 are upper limits, and the unmanned dump <NUM> travels at a speed lower than them depending on the situation in some cases. In an example in explained below, the unmanned dump <NUM> always travels at one of those upper limits.

The method for acquiring braking distances <NUM> and <NUM> can be designed as desired. For example, the braking distances <NUM> and <NUM> may be fixed values, may be the same value, or may be mutually different values. In addition, the braking distances <NUM> and <NUM> may be values computed on the basis of a travel speed. Functions representing the braking distances <NUM> and <NUM> using the travel speed as variables may be defined in advance. The formats of the functions can be designed as desired, and may be linear functions of a travel speed, may be quadratic functions of a travel speed, or may be functions in other formats.

Free running distances <NUM> and <NUM> can be computed on the basis of a travel speed and free running time, and can be computed by multiplying these, for example. For example, the free running time is a length of time that elapses until a communication interruption is detected after the occurrence of the communication interruption, and differs depending on the communication lines.

In the present embodiment, the free running time is set to a value which is equal to a communication delay of each communication line. That is, in a case where neither positional information nor an emergency stop signal can be received in a period equivalent to the communication delay, it is decided that a communication interruption is detected. Note that a communication delay of each communication line can be predetermined and stored in the manner mentioned above.

Positional information errors <NUM> and <NUM> are fixed values, and may be the same value or mutually different values for the communication lines.

As a specific example, in a case where time that has elapsed after the last reception of positional information about the manned vehicle <NUM> using the second communication line has become longer than the communication delay related to the second communication line, the unmanned dump <NUM> decides that a communication interruption of the second communication line is detected. A decision regarding the first communication line also may be made similarly.

The explanation above is summarized below. The reference distance Y is a constant. The braking distances <NUM> and <NUM> are constants or computed in accordance with functions including the travel speed related to each situation as variables. Since the free running time is a constant that differs depending on the situation as described above, the free running distances <NUM> and <NUM> also are computed in accordance with functions including the travel speed as variables. Both the positional information errors <NUM> and <NUM> are constants. Accordingly, the reference distance Y can be represented by an equation including, as a variable, the travel speed related to each situation, and by solving the equation, the travel speed related to each situation can be calculated. The specific calculation content for solving the equation can be designed by those skilled in the art as appropriate on the basis of a known technology or the like.

Regarding a case where only the first communication line is established, and a case where the second communication line is established in addition to the first communication line as depicted in <FIG>, specific examples of the method of calculating the travel speed related to each situation are explained below.

First, the case where only the first communication line is established is explained. It is supposed that the reference distance Y is <NUM>. It is supposed that the positional information error <NUM> in the case where only the first communication line is established is <NUM>. It is supposed that the braking distance <NUM> is a fixed value of <NUM>. In this case, the free running distance <NUM> is <NUM> - <NUM> - <NUM> = <NUM> [m]. Supposing that the communication delay of the first communication line is three seconds, the second speed V2 is <NUM>/<NUM> = <NUM> [m/s] = <NUM> [km/h].

Accordingly, in a case where it is decided that the inter-vehicle distance X to the manned vehicle <NUM> is equal to or shorter than the reference distance Y, the unmanned dump <NUM> is decelerated to <NUM>/h, and passes by the manned vehicle <NUM> at <NUM>/h. It is supposed that thereafter they move away from each other, and the inter-vehicle distance X becomes longer than the reference distance Y. In that case, the unmanned dump <NUM> travels at a predetermined normal speed V0 determined in advance. The normal speed V0 is a speed higher than the first speed V1 and the second speed V2, and is <NUM>/h, for example. By designing the normal speed V0 as a speed higher than the first speed V1 and the second speed V2 in this manner, normal-time operation efficiency is increased.

Next, the case where the second communication line also is established in addition to the first communication line is explained. It is supposed that the reference distance Y is <NUM> as well, and the positional information error <NUM> also is <NUM> as well. It is supposed that the braking distance <NUM> is a fixed value of <NUM>. In this case, the free running distance <NUM> is <NUM> - <NUM> - <NUM> = <NUM> [m]. Supposing that the communication delay of the second communication line is one second, the first speed V1 is <NUM>/<NUM> = <NUM> [m/s] = <NUM> [km/h].

Accordingly, in a case where it is decided that the inter-vehicle distance X to the manned vehicle <NUM> is equal to or shorter than the reference distance Y, the unmanned dump <NUM> is decelerated to <NUM>/h, and passes by the manned vehicle <NUM> at <NUM>/h while ensuring safety. In this manner, the unmanned dump <NUM> can continue travelling at a speed higher than the travel speed (<NUM>/h) of the unmanned dump <NUM> in a case where the first communication line is used, and it becomes possible to reduce unnecessary decelerations of autonomous travel vehicles while maintaining safety. In this manner, enhancement of the safety and enhancement of the productivity are attained at the same time.

Note that whereas a method of increasing a travel speed to which the unmanned dump <NUM> is decelerated while ensuring safety in a case where the unmanned dump <NUM> passes by the manned vehicle <NUM> is mentioned in the explanation described above, a method of shortening a length of time of deceleration while ensuring safety in a case where the unmanned dump <NUM> passes by the manned vehicle <NUM> may be adopted.

Next, with reference to a sequence diagram in <FIG>, the overall procedure of a manned vehicle <NUM>, an unmanned dump <NUM>, a relay base station <NUM>, and the central-control base station <NUM> in a case where the second communication line is established is explained. The unmanned dump <NUM> is travelling at the predetermined normal speed V0.

The manned vehicle <NUM> transmits, to the relay base station <NUM>, information about its own position by using the first communication line, that is, by using the infrastructure-to-vehicle communication <NUM> using the infrastructure-to-vehicle communication subframe <NUM>, at intervals of a predetermined length of time (e.g. one second). The relay base station <NUM> transmits, to the central-control base station <NUM>, the positional information about the manned vehicle <NUM> by using the infrastructure-to-infrastructure communication <NUM> using the infrastructure-to-infrastructure communication subframe <NUM>. The central-control base station <NUM> transmits, to the relay base station <NUM>, the positional information about the manned vehicle <NUM> by using the infrastructure-to-infrastructure communication <NUM> using the infrastructure-to-infrastructure communication subframe <NUM>. The relay base station <NUM> transmits, to the unmanned dump <NUM>, the positional information about the manned vehicle <NUM> by using the infrastructure-to-vehicle communication <NUM> using the infrastructure-to-vehicle communication subframe <NUM>. The communication delay of the first communication line is (T1 + T2 + T2 + T3).

In addition, the manned vehicle <NUM> directly transmits the information about its own position also by using the second communication line, that is, by using the vehicle-to-vehicle communication <NUM> using the vehicle-to-vehicle communication subframe <NUM>, at intervals of a predetermined length of time (e.g. one second). The communication delay of the second communication line includes only T4.

The unmanned dump <NUM> gets to be able to receive the second communication line, that is, the second communication line is established, when the manned vehicle <NUM> approaches the unmanned dump <NUM>. It is supposed that the manned vehicle <NUM> further approaches the unmanned dump <NUM>, and the inter-vehicle distance X has become equal to or shorter than the reference distance Y. In a case where the inter-vehicle distance X is equal to or shorter than the reference distance Y, the unmanned dump <NUM> decides whether or not the second communication line is established.

In a case where it is decided that the second communication line is established, the unmanned dump <NUM> sets the upper limit of its own travel speed to the first speed V1. The specific process of the speed control at this time can be designed by those skilled in the art as appropriate. Note that while the inter-vehicle distance X is equal to or shorter than the reference distance Y, the unmanned dump <NUM> may receive the positional information about the manned vehicle <NUM> transmitted by using the second communication line, and calculate the inter-vehicle distance X.

It is supposed that thereafter the manned vehicle <NUM> moves away from the unmanned dump <NUM>, and it is decided that the inter-vehicle distance X between the manned vehicle <NUM> and the unmanned dump <NUM> has become longer than the reference distance Y. In a case where the inter-vehicle distance X is longer than the reference distance Y, the unmanned dump <NUM> sets the upper limit of its own travel speed to the normal speed V0. The specific process of the speed control at this time can be designed by those skilled in the art as appropriate.

Next, with reference to a sequence diagram in <FIG>, the overall procedure of a manned vehicle <NUM>, an unmanned dump <NUM>, a relay base station <NUM>, and the central-control base station <NUM> in a case where the second communication line is not established is explained. The manned vehicle <NUM> is travelling at the predetermined normal speed V0.

Similarly to the case in <FIG>, the manned vehicle <NUM> uses the first communication line and the second communication line to transmit information about its own position.

Although the unmanned dump <NUM> is designed to be capable of receiving the second communication line if the manned vehicle <NUM> has approached the unmanned dump <NUM>, the second communication line is not established depending on the wireless environment, in some cases. It is supposed that when the manned vehicle <NUM> approaches the unmanned dump <NUM>, and the inter-vehicle distance X has become equal to or shorter than the reference distance Y, it is decided that the second communication line is not established. In this case, the unmanned dump <NUM> sets the upper limit of its own travel speed to the second speed V2. The specific process of the speed control at this time can be designed by those skilled in the art as appropriate. In this case, the unmanned dump <NUM> receives positional information about the manned vehicle <NUM> transmitted by using the first communication line, and calculates the inter-vehicle distance X.

It is supposed that thereafter if the manned vehicle <NUM> moves away from the unmanned dump <NUM>, the unmanned dump <NUM> sets the upper limit of its own travel speed to the normal speed V0, similarly to the case in <FIG>.

Note that although not depicted, an emergency stop signal is transmitted along with the positional information, and it is possible for the manned vehicle <NUM> to emergently stop the unmanned dump <NUM> any time by operation of the emergency stop button.

Note that in a case where the second communication line has been established at a time point at which the inter-vehicle distance X between the manned vehicle <NUM> and the unmanned dump <NUM> has become equal to or shorter than the reference distance Y, and thereafter the second communication line is no longer established while the inter-vehicle distance X is equal to or shorter than the reference distance Y, speed control is executed such that the travel speed of the unmanned dump <NUM> is switched from the first speed V1 to the second speed V2.

As explained above, according to the vehicle control system of the first embodiment, in a case where it is decided that the inter-vehicle distance X between the unmanned dump <NUM> and the manned vehicle <NUM> is equal to or shorter than the reference distance Y decided in advance, the unmanned dump <NUM> decides whether or not the second communication line is established. Then, in a case where the second communication line is established and communication therethrough is possible, the travel speed of the unmanned dump <NUM> can be increased or the deceleration time can be shortened as compared to a case where the second communication line is not established and communication therethrough is not possible, and thus the mining work efficiency of a mine can be enhanced.

Note that the method for deciding whether or not the second communication line is established can be designed by those skilled in the art as desired. For example, the decision can be made on the basis of received power, a bit error rate, a packet error rate, and the like, but these are not the sole examples.

According to this first embodiment, a vehicle control system that makes it possible to ensure the safety and enhance the productivity at the same time can be provided.

Note that whereas control is performed to decelerate an unmanned dump <NUM> at a time of approach in the explanation described above, instead of deceleration, control can also be performed to cause an unmanned dump <NUM> to take a bypass route, and so on. That is, as long as a technique for avoiding a collision between an unmanned dump <NUM> and another vehicle or the like is adopted, the method of avoiding such a collision is not limited to a particular one.

A block diagram in <FIG> depicts a configuration example of the vehicle-mounted transmitting terminals <NUM> according to the embodiment described above. As an example, a vehicle-mounted transmitting terminal <NUM> has a transmission/reception antenna <NUM>, a wireless apparatus <NUM>, a power supply apparatus <NUM>, a display apparatus <NUM>, an emergency stop button <NUM>, a controller <NUM>, a GPS receiver <NUM>, and a GPS antenna <NUM>. In addition, the controller <NUM> includes a microcomputer apparatus <NUM> and a baseband apparatus <NUM>. The wireless apparatus <NUM> may have the functionality of the baseband apparatus <NUM>.

The power supply apparatus <NUM> includes, a battery <NUM>, a voltage converter <NUM>, and the like. The power supply apparatus <NUM> has a functionality of converting electric power supplied from the battery <NUM> into a required voltage at the voltage converter <NUM>, and thereafter supplying the electric power to each section in the vehicle-mounted transmitting terminal <NUM>.

The display apparatus <NUM> includes an LED, a liquid crystal display apparatus, or the like, and is connected to the power supply apparatus <NUM> and the microcomputer apparatus <NUM>. The display apparatus <NUM> has a functionality of informing an operator of the normality of the power supply and a result of an out-of-range determination about a wireless area.

The emergency stop button <NUM> is connected with the microcomputer apparatus <NUM> of the controller <NUM>, and includes an operation button to be used by the operator to give a command for emergently stopping an unmanned dump <NUM>. Similarly to the emergency stop input apparatus <NUM> of the control center <NUM>, the emergency stop button <NUM> gives a command for emergently stopping the unmanned dump <NUM>, but this emergency stop button <NUM> is provided in the vehicle-mounted transmitting terminal <NUM>. The emergency stop button <NUM> can have a press-button structure that detects that an instruction from the operator is given when the emergency stop button <NUM> is pressed. In addition, it is desirable if the emergency stop button <NUM> has such a mechanism that it is locked in a case where it is pressed, and is kept being pressed unless an unlocking operation is performed.

The GPS receiver <NUM> is connected with the GPS antenna <NUM> and the microcomputer apparatus <NUM> of the controller <NUM>, and acquires positional information representing the current position of the manned vehicle <NUM> from a GPS reception signal received via the GPS antenna <NUM>. The GPS receiver <NUM> outputs the positional information representing the current position of the manned vehicle <NUM> to the microcomputer apparatus <NUM> regularly (e.g. every second).

The microcomputer apparatus <NUM> of the controller <NUM> is a microcomputer. The microcomputer apparatus <NUM> is connected with the display apparatus <NUM>, the emergency stop button <NUM>, the baseband apparatus <NUM>, and the GPS receiver <NUM>.

The microcomputer apparatus <NUM> has a CPU <NUM> (calculation processing apparatus) and a storage apparatus <NUM> (a main memory, a flash memory, etc.). By calculations of a program stored on the storage apparatus <NUM> being executed by the CPU <NUM>, functionalities explained below are realized.

Part or the whole of the microcomputer apparatus <NUM> may be configured by using an integrated circuit or the like. In addition to the functionalities described above, the microcomputer apparatus <NUM> makes a determination as to whether the power supply apparatus <NUM> is operating normally, and an out-of-range determination as to whether or not the manned vehicle <NUM> is in a wireless area formed by each relay base station <NUM> and the central-control base station <NUM>.

The baseband apparatus <NUM> of the controller <NUM> is a unit that is configured by using an integrated circuit or the like, and performs communication with another apparatus in accordance with the time division multiplexing method. The baseband apparatus <NUM> outputs a signal in a subframe allocated in advance or in a subframe allocated to itself by the infrastructure-to-infrastructure communication <NUM>, in a plurality of subframes obtained by dividing specified unit time (e.g. one second). Under the control of the microcomputer apparatus <NUM>, the baseband apparatus <NUM> controls the wireless apparatus <NUM> such that a signal is transmitted in a subframe allocated to itself.

on the basis of control by the baseband apparatus <NUM>, the wireless apparatus <NUM> implements processes such as error correcting coding, modulation, frequency conversion, filtering, or amplification on data output from the baseband apparatus <NUM>, and generates a wireless signal. The wireless apparatus <NUM> sends the generated wireless signal to the transmission/reception antenna <NUM>.

Next, operation of a vehicle-mounted transmitting terminal <NUM> is explained in detail with reference to a flowchart in <FIG>. It is supposed that the flowchart in <FIG> is implemented at intervals of a predetermined length of time (e.g. one second).

As a first communication method, the vehicle-mounted transmitting terminal <NUM> sets parameters such that the baseband apparatus <NUM> of the vehicle-mounted transmitting terminal <NUM> operates on the first communication line (Step S002). For example, a modulation method and a coding rate used for the first communication line are set.

In parallel with this, as a second communication method, the vehicle-mounted transmitting terminal <NUM> sets parameters such that the baseband apparatus <NUM> of the vehicle-mounted transmitting terminal <NUM> operates on the second communication line (Step S006). For example, a modulation method and a coding rate used for the second communication line are set.

After the communication method of the first communication line is set, the GPS antenna <NUM> of the vehicle-mounted transmitting terminal <NUM> receives a GPS signal (Step S003), and, on the basis of the GPS signal, the GPS receiver <NUM> acquires positional information representing the current position of the manned vehicle <NUM> (Step S004). Then, the microcomputer apparatus <NUM> generates information data about its own position for the first communication line (Step S005).

After the communication method of the second communication line is set, operation identical to Steps <NUM> and <NUM> is performed at Steps S007 and <NUM>. The microcomputer apparatus <NUM> generates information data about its own position for the second communication line (Step S009).

Subsequently, the process proceeds to Step S010, and it is determined whether or not the emergency stop button <NUM> is being pressed. In a case where it is determined that the emergency stop button <NUM> is not being pressed (No at Step S010), the microcomputer apparatus <NUM> generates an emergency stop signal "<NUM>" on an application layer <NUM> (Step S011). On the other hand, in a case where it is determined that the emergency stop button <NUM> is being pressed (Yes at Step S010), the microcomputer apparatus <NUM> generates an emergency stop signal "<NUM>" on the application layer <NUM> (Step S012). The emergency stop signal "<NUM>" is an emergency stop command signal.

Then, the microcomputer apparatus generates transmission data including the obtained positional information and emergency stop signal (Step S013). The generated transmission data is subjected to a transmission process necessary for functional safety on a safety communication layer <NUM>, and then transmitted (Step S014). The baseband apparatus <NUM> implements, on the received data, a transmission process necessary for wireless communication on a wireless communication layer <NUM>.

In a case where the data after being subjected to the transmission process is transmission data generated in accordance with the first communication method, the data is output to the wireless apparatus <NUM> at a timing at which it is transmitted in a relevant slot of the infrastructure-to-vehicle communication subframe <NUM> (Step S015). In a case where the data is transmission data generated according to the second communication method, the data is output to the wireless apparatus <NUM> at a timing at which it is transmitted in a relevant slot of the vehicle-to-vehicle communication subframe <NUM> (Step S015 as well).

The wireless apparatus <NUM> implements processes such as modulation, frequency conversion, filtering, or amplification on the data received from the baseband apparatus <NUM>, and outputs an ACK signal from the transmission/reception antenna <NUM> (Step S016). The process loops back to START (S001) every second after this Step S016 is ended.

By the operation according to the flowchart in <FIG>, information about its own position is transmitted regularly, and while the emergency stop button <NUM> is being pressed (S010: Yes), "<NUM>" is transmitted as an emergency stop signal continuously (i.e. an emergency stop command signal is transmitted). In addition, if the emergency stop button <NUM> is unlocked (S010: No), the microcomputer apparatus <NUM> transmits "<NUM>" as the emergency stop signal.

Note that by executing the communication method of the first communication line and the communication method of the second communication line in parallel in <FIG>, it becomes possible to perform stable communication even if the communication distance of the first communication line and the communication distance of the second communication line are significantly different from each other. In addition, the precision of positional information related to the first communication line and the precision of positional information related to the second communication line may be made different from each other.

Since, even if the second communication line is not established, information about its own position is transferred stably by the first communication line, and additionally an emergency stop signal also is transferred, thus the safety never becomes a problem. On the other hand, in a case where the second communication line is established, it becomes possible to increase the travel speed to which an unmanned dump <NUM> is decelerated, shorten the deceleration time, and so on, thereby attaining enhancement of the productivity.

Note that whereas an embodiment is explained by using, as an example, unmanned dumps of a mining site in the embodiment described above, autonomous travel vehicles are not limited to unmanned dumps at a mine, but may be manned dumps, and may be construction machines or the like at a construction site.

As explained in detail thus far, according to the present embodiment, it is possible to increase the travel speed to which an autonomously-travelling unmanned dump is decelerated, shorten the deceleration time, remotely stopping a moving haulage vehicle at a time of emergency, and so on.

Claim 1:
A vehicle control system (<NUM>) comprising:
an autonomous travel vehicle (<NUM>);
a manned vehicle (<NUM>); and
a plurality of communication lines (<NUM>, <NUM>, <NUM>) configured to connect the autonomous travel vehicle (<NUM>) and the manned vehicle (<NUM>) with each other, wherein
the manned vehicle (<NUM>) is configured to transmit positional information about the manned vehicle (<NUM>) by using a first communication line (<NUM>),
the autonomous travel vehicle (<NUM>) is configured to use the first communication line (<NUM>) to receive the positional information about the manned vehicle (<NUM>),
the autonomous travel vehicle (<NUM>) is configured to decide whether or not an inter-vehicle distance (X) between the autonomous travel vehicle (<NUM>) and the manned vehicle (<NUM>) is equal to or shorter than a reference distance (Y) on a basis of the positional information about the manned vehicle (<NUM>) and positional information about the autonomous travel vehicle (<NUM>),
in a case where the inter-vehicle distance (X) is equal to or shorter than the reference distance (Y), the autonomous travel vehicle (<NUM>) is configured to
- decide whether or not a second communication line (<NUM>) that uses a communication path different from the first communication line (<NUM>) is established between the autonomous travel vehicle (<NUM>) and the manned vehicle (<NUM>),
- set an upper limit of a travel speed of the autonomous travel vehicle (<NUM>) to a first speed (V1) in a case where it is decided that the second communication line (<NUM>) is established, and travels under the upper limit,
- set the upper limit of the travel speed of the autonomous travel vehicle (<NUM>) to a second speed (V2), which is not zero, in a case where it is decided that the second communication line (<NUM>) is not established, and travels under the upper limit, wherein
a communication delay related to the second communication line (<NUM>) is shorter than a communication delay related to the first communication line (<NUM>), and wherein
the first speed (V1) is higher than the second speed (V2).