Patent Description:
<CIT> discloses a device for use with a railroad vehicle at least not having the features of the characterizing portion of claim <NUM>.

A railroad vehicle disclosed in <CIT> (the ‴<NUM> Publication") includes rotational speed sensors for detecting the rotational speed of axles onto which wheels are fixed. There are, in total, four rotational speed sensors corresponding to four axles.

The railroad vehicle disclosed in the '<NUM> Publication detects the rotational speed of the four axles and calculates the differences between the detected values of the rotational speed. Based on the calculated differences between the values of the rotational speed, the railroad vehicle can detect whether wheel slide is occurring on the rail. The railroad vehicle disclosed in the '<NUM> Publication attempts to, while wheel slide is occurring, take care of the ongoing wheel slide by reducing the braking force produced by the brake device.

The railroad vehicle disclosed in the '<NUM> Publication may be capable of detecting wheel slide and controlling the braking force to address the ongoing wheel slide, but has no way of predicting where the wheels of the railroad vehicle are likely to slide.

The present invention is made in light of the above, and one object thereof is to predict the position where the wheels of a railroad vehicle slide. Said object is achieved by a device for use with a railroad vehicle according to claim <NUM> and a control method according to claim <NUM>.

According to one aspect of the present disclosure, a device for use with a railroad vehicle, the device includes processing circuitry, and a memory coupled to the processing circuitry. The processing circuitry is configured to acquire position information of a railroad vehicle on a rail, determine, based on a rotational speed of a wheel of the railroad vehicle, whether the wheel is sliding, and store in the memory, as wheel slide information, position information of the railroad vehicle on the rail observed when the wheel has slid.

With the above configurations, the wheel slide information can be stored that includes the position information regarding the position where the wheel has slid. according to the invention, the stored wheel slide information iis aggregated and analyzed, so that the position where the wheel of the railroad vehicle slides can be predicted.

In the device having the above configurations, the wheel slide information may include at least one of speed information of the railroad vehicle observed when the wheel has slid, information indicative of deceleration of the railroad vehicle observed when the wheel has slid and information regarding a weight of the railroad vehicle observed when the wheel has slid.

In the device having the above configurations, the wheel slide information includes information that may affect the likelihood of the sliding of the wheel, such as the speed information of the railroad vehicle, the information indicative of the deceleration of the railroad vehicle, and the information regarding the weight of the railroad vehicle. The above configurations can accordingly contribute to improve the accuracy of the prediction of the sliding of the wheel based on the wheel slide information.

In the device having the above configurations, the wheel slide information may include weather information observed when the wheel has slid. The likelihood of the wheel slide of the railroad vehicle on the position where the wheel has slid varies depending on, for example, whether it is raining. With the above configurations, the sliding of the wheel can be predicted more accurately by using the wheel slide information. This is because the wheel slide information contains weather information that may affect the likelihood of the sliding of the wheel.

In the device having the above configurations, the processing circuitry is further configured to calculate, based on the wheel slide information, a predicted wheel slide position where the wheel possibly slides, and cause a report device of the railroad vehicle to issue a report based on a current position of the railroad vehicle on the rail and the predicted wheel slide position.

With the above configurations, the wheel slide information can be used to calculate and predict a predicted wheel slide position where the wheel of the railroad vehicle may possibly slide. The report device then reports the predicted wheel slide position. In this way, a driver or other passengers can more easily know that there is a predicted wheel slide position.

In the device having the above configurations, the processing circuitry is further configured to cause the report device to issue a report when a distance between the current position of the railroad vehicle on the rail and the predicted wheel slide position becomes equal to or less than a predetermined distance.

With the above configurations, when the railroad vehicle approaches the predicated wheel slide position, the report device reports that the railroad vehicle is approaching the predicted wheel slide position. This allows the driver or other passengers to easily know that the railroad vehicle is traveling near the predicted wheel slide position when the railroad vehicle approaches the predicted wheel slide position.

In the device having the above configurations, the processing circuitry is further configured to calculate, based on the wheel slide information, a predicted wheel slide position where the wheel possibly slides, and control a brake device of the railroad vehicle such that a deceleration rate of the railroad vehicle observed when the railroad vehicle is on the predicted wheel slide position is equal to or less than a predetermined deceleration rate.

With the above configurations, when the railroad vehicle is on the predicated wheel slide position, the deceleration rate of the railroad vehicle is limited. If the deceleration rate of the railroad vehicle is limited in this way, the brake device does not produce excessively strong braking force, which can prevent the railroad vehicle from experiencing wheel slide at the predicted wheel slide position.

In the device having the above configurations, the processing circuitry is further configured to calculate, based on the wheel slide information, a predicted wheel slide position where the wheel possibly slides, and control a brake device of the railroad vehicle such that a speed of the railroad vehicle observed when the railroad vehicle is on the predicted wheel slide position is equal to or less than a predetermined speed.

With the above configurations, when the railroad vehicle is on the predicated wheel slide position, the speed of the railroad vehicle is limited. Accordingly, it is less necessary to increase the braking force produced by the brake device at the predicted wheel slide position. Consequently, the wheel of the railroad vehicle can be prevented from sliding at the predicted wheel slide position.

According to one aspect of the present disclosure, a wheel slide information generating method includes steps of acquiring position information of a railroad vehicle on a rail, determining, based on a rotational speed of a wheel of the railroad vehicle, whether the wheel is sliding, storing in a storing unit, as wheel slide information, position information of the railroad vehicle on the rail observed when the wheel has slid.

In the above method, wheel slide information can be stored that includes position information on the position where the wheel has slid. Accordingly, for example, the stored wheel slide information can be aggregated and analyzed, so that the position where the wheel of the railroad vehicle slides can be predicted.

The following describes a first embodiment with reference to <FIG>.

To begin with, the schematic configuration of a train <NUM>, which is a railroad train, will be described.

As shown in <FIG>, the train <NUM> includes four vehicles <NUM> coupled together, which are arranged next to each other in the front-and-back direction (the left-and-right direction in <FIG>) of the train <NUM>. The vehicles <NUM> are coupled such that each vehicle <NUM> is coupled to adjacent vehicles <NUM> in the front-and-back direction and identified by the reference numerals 10A, 10B, 10C and 10D in the stated order from the front side. Each vehicle <NUM> has substantially the same configuration and the following thus specifically describes only the vehicle 10A.

As shown in <FIG>, the vehicle 10A includes two bogies <NUM> spaced away from each other in the front-and-back direction (the left-and-right direction in <FIG>) of the vehicle 10A. Each bogie <NUM> has axles <NUM> attached thereto in a rotatable manner. The axles <NUM> extend in the width direction (the direction orthogonal to the plane of paper in <FIG>). For each bogie <NUM>, two axles <NUM> are provided and spaced away from each other in the front-and-back direction. On both ends of each axle <NUM>, wheels <NUM> substantially shaped like a disk are fixed. Accordingly, each bogie <NUM> has four wheels <NUM> provided. In <FIG>, the reference numerals are appended to only some of the bogies <NUM>, axles <NUM> and wheels <NUM>.

As shown in <FIG>, air springs <NUM>, which utilize elastic force provided by compressed air to absorb vibration, are attached on the upper side of the bogies <NUM>. A vehicle body <NUM> is attached on the upper side of the air springs <NUM>. The vehicle body <NUM> bounds an in-vehicle space. The vehicle body <NUM> is as a whole shaped like a rectangular parallelepiped box and has a long dimension in the front-and-back direction of the vehicle 10A. In <FIG>, the reference numerals are appended to some of the air springs <NUM> and vehicle bodies <NUM>.

As shown in <FIG>, a brake device <NUM> is attached to each bogie <NUM>. The brake device <NUM> is designed to slow the rotation of the wheel <NUM>. The brake device <NUM> is of a tread brake type and configured to slow the rotation of the wheel <NUM> by bringing the brake shoe serving as a frictional member into contact with the wheel tread of the wheel <NUM> or the outer peripheral surface. The vehicle 10A has, in total, eight brake devices <NUM> attached thereto, which correspond to the eight wheels <NUM>. <FIG> only shows four wheels <NUM> and four brake devices <NUM>, which are positioned on one of the sides defined in the width direction.

The vehicle 10A has an air supply source <NUM> attached thereto. The air supply source <NUM> is configured to supply compressed air. The air supply source <NUM> has a supply channel <NUM> extending therefrom. The supply channel <NUM> branches into eight in the middle, and each branch channel is connected to one of the eight brake devices <NUM>. To the supply channel <NUM>, a control valve <NUM> is attached that is configured to control the amount of the air distributed through the supply channel <NUM>. The control valve <NUM> is arranged on the air supply source <NUM> side with respect to the origin of the branches in the supply channel <NUM>. This means that one control valve <NUM> is provided for the eight brake devices <NUM>. The air supply source <NUM> is also connected to the air springs <NUM> through channels, which are not illustrated. The air springs <NUM> receive compressed air supplied from the air supply source <NUM>.

Inside the vehicle body <NUM>, a display <NUM> is attached, which serves as a report device. The display <NUM> displays a variety of information to transmit information to, for example, the driver of the train <NUM>. The display <NUM> is installed only in the vehicles 10A and 10D, from among the vehicles 10A to 10D.

Each of the above-described air springs <NUM> has a pressure sensor <NUM> attached thereto in order to detect the air pressure X1 of the air spring <NUM>. The above-described bogies <NUM> have rotation sensors <NUM> attached thereto in order to detect the axial rotational speed X2, which represents the rotational speed of the axles <NUM>. Each rotation sensor <NUM> is arranged in the vicinity of a corresponding one of the axles <NUM>, and the vehicle 10A has, in total, four rotation sensors <NUM> provided. <FIG> shows only one of the rotation sensors <NUM>.

In the vehicle 10A having the above-described configurations, the brake devices <NUM> are controlled by a control device <NUM>. The control device <NUM> receives, from the pressure sensors <NUM>, signals indicative of the values of the air pressure X1 of the air springs <NUM>, which are detected by the pressure sensors <NUM>. The control device <NUM> acquires the total weight Y1 of the vehicle body <NUM> based on the values of the air pressure of the air springs <NUM>. Here, the total weight Y1 of the vehicle body <NUM> is the total sum of the weight of the vehicle body <NUM> itself and the weight of the passengers and the like in the vehicle body <NUM>. The control device <NUM> also receives, from the rotation sensors <NUM>, signals indicative of the values of the axial rotational speed X2 of the axles <NUM>, which are detected by the rotation sensors <NUM>. Since the vehicle 10A has, in total, the four rotation sensors <NUM> as described above, the control device <NUM> receives from each rotation sensor <NUM> the signal indicative of the axial rotational speed X2.

The control device <NUM> also receives a signal indicative of a brake instruction X6 from a brake controller <NUM>, which is operated by the driver of the train <NUM>. The brake controller <NUM> includes a lever configured to be operated by the driver. The brake controller <NUM> has a plurality of notches corresponding to different levels for defining the position to which this lever is to be operated and is configured to output a signal indicative of the brake instruction X6 corresponding to the position of the lever, which results from the operation of the lever by the driver. The brake instruction X6 increases in steps depending on the position of the lever, which results from the operation of the lever by the driver.

The control device <NUM> is capable of communicating with a weather service center <NUM> via an external communication line network <NUM>. The control device <NUM> acquires weather information from the weather service center <NUM>. Here, the weather information includes information regarding weather such as rain. The weather information also includes information regarding the current time.

The control device <NUM> includes a wheel slide determining unit <NUM> for determining whether the wheels <NUM> of the vehicle <NUM> are sliding. The wheel slide determining unit <NUM> determines, based on the axial rotational speed X2, whether the wheels <NUM> of the vehicle <NUM> are sliding (a wheel slide determining step). The wheel slide determining step is performed by the wheel slide determining unit <NUM>.

The control device <NUM> includes a storing unit <NUM> for storing wheel slide information of the vehicle <NUM>. The wheel slide information includes the following plurality of items. The first item of the wheel slide information is position information associating the position of the vehicle <NUM> on the rail where the wheels <NUM> of the vehicle <NUM> have slid with the fact that the wheels <NUM> of the vehicle <NUM> have slid. The second item of the wheel slide information is speed information associating the speed of the vehicle <NUM> observed when the wheels <NUM> of the vehicle <NUM> have slid with the fact that the wheels <NUM> of the vehicle <NUM> have slid. The third item of the wheel slide information is deceleration information associating the deceleration of the vehicle <NUM> observed when the wheels <NUM> of the vehicle <NUM> have slid with the fact that the wheels <NUM> of the vehicle <NUM> have slid. The brake instruction X6 determined by the position of the lever resulting from the operation of the lever by the driver is employed as the deceleration information. The fourth item of the wheel slide information is weight information associating the weight of the vehicle <NUM> observed when the wheels <NUM> of the vehicle <NUM> have slid with the fact that the wheels <NUM> of the vehicle <NUM> have slid. The total weight Y1 of the vehicle body <NUM> is employed as the weight information. The fifth item of the wheel slide information is weather information associating weather information regarding the position of the vehicle <NUM> on the rail where the wheels <NUM> of the vehicle <NUM> have slid with the fact that the wheels <NUM> of the vehicle <NUM> have slid. As the weather information, information about precipitation is employed.

The control device <NUM> includes a generating unit <NUM> for generating the wheel slide information. The generating unit <NUM> generates wheel slide information of the vehicle <NUM> and stores the generated wheel slide information in the storing unit <NUM> (storing step). The control device <NUM> additionally includes a wheel slide predicting unit <NUM> for calculating, at a timing later than the timing at which the wheel slide information is generated, a predicted wheel slide position where the wheels <NUM> of the vehicle <NUM> may possibly slide. The wheel slide predicting unit <NUM> calculates, based on the wheel slide information generated by the generating unit <NUM>, the information indicating the state of the vehicle <NUM> and the weather information, a predicted wheel slide position where the wheels <NUM> of the vehicle <NUM> may possibly slide. The control device <NUM> includes an acquiring unit <NUM> for acquiring position information of the vehicle <NUM> on the rail. The acquiring unit <NUM> acquires position information of the vehicle <NUM> on the rail based on the axial rotational speed X2 (acquiring step). The storing step is performed by the generating unit <NUM>. The acquiring step is performed by the acquiring unit <NUM>.

The control device <NUM> includes a distance determining unit <NUM> for calculating a reach distance between the position of the vehicle <NUM> on the rail and the predicted wheel slide position ahead in the traveling direction of the vehicle <NUM>. The distance determining unit <NUM> determines whether the reach distance is equal to or less than a predetermined distance. The distance determining unit <NUM> calculates the reach distance based on the axial rotational speed X2.

The control device <NUM> includes a brake control unit <NUM> for controlling the brake devices <NUM>. More specifically, the brake control unit <NUM> controls the aperture of the control valve <NUM> by outputting a control signal determined by the brake instruction X6 to the control valve <NUM>. By adjusting the aperture of the control valve <NUM>, the amount of the air distributed through the supply channel <NUM> can be adjusted. In this way, the brake devices <NUM> are driven. Accordingly, the brake control unit <NUM> collectively controls all of the eight brake devices <NUM> through the single control valve <NUM> provided in the vehicle 10A. The control signal output from the brake control unit <NUM> is configured such that, as the brake instruction X6 increases, the braking force produced by the brake devices <NUM> increases.

The control device <NUM> includes a report control unit <NUM> for causing the display <NUM> to display a variety of information. More specifically, the report control unit <NUM> causes the display <NUM> to display a variety of information by outputting to the display <NUM> an image signal indicating a variety of information based on the current position of the vehicle <NUM> on the rail and the predicted wheel slide position on the rail. As the control device <NUM> includes the wheel slide determining unit <NUM>, the storing unit <NUM> and the acquiring unit <NUM>, the control device <NUM> partially serves as a wheel slide information generating device. As the control device <NUM> includes the wheel slide determining unit <NUM>, the storing unit <NUM>, the wheel slide predicting unit <NUM>, the acquiring unit <NUM> and the report control unit <NUM>, the control device <NUM> partially serves as a wheel slide predicting device.

The control device <NUM> may be formed by circuitry including one or more processors for performing various processes in accordance with computer programs (software). The control device <NUM> may be formed by one or more dedicated hardware circuits such as application-specific integrated circuits (ASICs) that perform at least some of the various processes, or by circuitry including a combination of such circuits. The processor includes processing circuitry such as a CPU, and a memory such as a RAM or ROM. The memory stores therein program codes or instructions configured to cause the CPU to perform processes. The memory, or a computer-readable medium, encompasses any kind of available media accessible by a general-purpose or dedicated computer. As shown in <FIG>, the control device <NUM> is capable of communicating with the control devices <NUM> in the other three vehicles <NUM>.

The following now describes a series of controls to determine wheel slide, which are performed by the control device <NUM>. The control device <NUM> repeatedly performs a series of controls to determine wheel slide while the vehicle <NUM> is traveling. More specifically, the control device <NUM> performs a series of controls to determine wheel slide when any of the values of the axial rotational speed X2 detected by the rotation sensors <NUM> is determined to be larger than zero. The control device <NUM> in the vehicle 10A represents the four control devices <NUM> in the vehicles 10A to 10D and performs a series of controls to determine wheel slide.

As shown in <FIG>, once the control device <NUM> starts the series of controls to determine wheel slide, the control device <NUM> starts the process in a step S11. In the step S11, the wheel slide determining unit <NUM> in the control device <NUM> determines whether the wheels <NUM> of the vehicle <NUM> are sliding. If the wheels <NUM> of the vehicle <NUM> are sliding, some of the wheels <NUM> are stopped from rotating by the corresponding brake devices <NUM> and some of the values of the axial rotational speed X2 become or approach zero. On the other hand, the other wheels <NUM> are still rotating. Therefore, the four values of the axial rotational speed X2 vary significantly from each other. The wheel slide determining unit <NUM> calculates the variation among the values of the axial rotational speed X2 by subtracting the smallest value among the four values of the axial rotational speed X2 in the vehicle <NUM> from the largest value among the four values of the axial rotational speed X2 in the vehicle <NUM>. When the variation among the values of the axial rotational speed X2 is equal to or more than a predetermined reference variation, the wheel slide determining unit <NUM> determines that the wheels <NUM> of the vehicle <NUM> are sliding. When the variation among the values of the axial rotational speed X2 is less than the predetermined reference variation, the wheel slide determining unit <NUM> determines that the wheels <NUM> of the vehicle <NUM> are not sliding. When determining that the wheels <NUM> of the vehicle <NUM> are not sliding in the step S11 (S11: NO), the control device <NUM> terminates the current series of controls to determine wheel slide. On the other hand, in the step S11, when determining that the wheels <NUM> of the vehicle <NUM> are sliding (S11: YES), the control device <NUM> proceeds to a step S12.

In the step S12, the generating unit <NUM> in the control device <NUM> generates wheel slide information of the vehicle <NUM> and stores the generated wheel slide information in the storing unit <NUM>. To begin with, the acquiring unit <NUM> acquires the current position of the vehicle <NUM> on the rail. More specifically, the acquiring unit <NUM> of the control device <NUM> calculates the current speed of the vehicle <NUM> based on the largest value among the four values of the axial rotational speed X2 in the vehicle <NUM>. Following this, the acquiring unit <NUM> calculates, based on the speed of the vehicle <NUM>, the travel distance per unit time. The acquiring unit <NUM> repeatedly calculates the speed and travel distance at unit time intervals. The acquiring unit <NUM> further calculates a cumulative sum of the travel distance after the departure from a predetermined reference position to a current position in order to calculate the total travel distance and acquires, as the current position of the vehicle <NUM> on the rail, the position away from the reference position by the total travel distance. The generating unit <NUM> acquires the current position of the vehicle <NUM> on the rail, which is acquired by the acquiring unit <NUM>, as the position of the vehicle <NUM> on the rail where the wheels <NUM> of the vehicle <NUM> have slid.

The generating unit <NUM> also acquires the speed of the vehicle <NUM> calculated in the above-described manner as the speed information of the vehicle <NUM> indicating the speed observed when the wheels <NUM> of the vehicle <NUM> have slid. The generating unit <NUM> further acquires the current brake instruction X6 as the deceleration information indicating the deceleration of the vehicle <NUM> observed when the wheels <NUM> of the vehicle <NUM> have slid. The generating unit <NUM> further acquires the total weight Y1 of the vehicle body <NUM> as the weight information of the vehicle <NUM> indicating the weight observed when the wheels <NUM> of the vehicle <NUM> have slid. The generating unit <NUM> further acquires the current weather information at the current position of the vehicle <NUM> on the rail as the weather information indicating weather at the position of the vehicle <NUM> on the rail observed when the wheels <NUM> of the vehicle <NUM> have slid. The generating unit <NUM> stores these pieces of information in the storing unit <NUM> as the wheel slide information of the vehicle <NUM> in association with the fact that the wheels <NUM> of the vehicle <NUM> have slid. In other words, the storing unit <NUM> stores the wheel slide information generated by the generating unit <NUM>. After this, the control device <NUM> terminates the current series of controls to determine wheel slide.

Note that the control device <NUM> in the vehicle 10A performs the above-described controls in the steps S11 and S12 not only for the vehicle 10A but also for the other vehicles 10B to 10D in parallel.

The following now describes a series of controls to predict wheel slide, which are performed by the control device <NUM>. The control device <NUM> repeatedly performs a series of controls to predict wheel slide while the vehicle <NUM> is traveling. More specifically, the control device <NUM> performs a series of controls to predict wheel slide when any of the values of the axial rotational speed X2 detected by the rotation sensors <NUM> is determined to be larger than zero. The control device <NUM> in the vehicle 10A represents the four control devices <NUM> in the vehicles 10A to 10D and performs a series of controls to predict wheel slide.

As shown in <FIG>, once the control device <NUM> starts the series of controls to predict wheel slide, the control device <NUM> starts the process in a step S61. In the step S61, the control device <NUM> acquires weather information from the weather service center <NUM>. The control device <NUM> also acquires the information indicating the state of the vehicle <NUM>. After this, the control device <NUM> proceeds to a step S62.

In the step S62, the wheel slide predicting unit <NUM> in the control device <NUM> uses the wheel slide information at the time of performing the step S61, the information indicating the state of the vehicle <NUM> at the time of performing the step S61 and the weather information at the time of performing the step S61 in order to calculate a predicted wheel slide position, at which the wheels <NUM> of the vehicle <NUM> may possibly slide in the future.

In order to calculate the predicted wheel slide position, the wheel slide predicting unit <NUM> selects, as candidate predicted wheel slide positions, the positions of the vehicle <NUM> on the rail where the wheels <NUM> of the vehicle <NUM> have slid, which are included in the wheel slide information. For each candidate predicated wheel slide position, the wheel slide predicting unit <NUM> calculates a wheel slide likelihood score indicative of the likelihood of wheel slide for the wheels <NUM> of the currently traveling vehicle <NUM>, in the following manner that is not part of the claimed invention but supports its disclosure.

For the candidate predicted wheel slide position, the wheel slide predicting unit <NUM> refers to the variety of information stored as the wheel slide information in association with the candidate predicted wheel slide position. More specifically, the wheel slide predicting unit <NUM> increases the wheel slide likelihood score calculated for a candidate predicted wheel slide position as the precipitation included in the corresponding wheel slide information decreases. Furthermore, the wheel slide predicting unit <NUM> increases the wheel slide likelihood score calculated for a candidate predicted wheel slide position as the speed of the vehicle <NUM> included in the corresponding wheel slide information decreases. Additionally, the wheel slide predicting unit <NUM> increases the wheel slide likelihood score calculated for a candidate predicted wheel slide position as the brake instruction X6 included in the corresponding wheel slide information as the deceleration information decreases. Furthermore, the wheel slide predicting unit <NUM> increases the wheel slide likelihood score calculated for a candidate predicted wheel slide position as the total weight Y1 of the vehicle body <NUM> included in the corresponding wheel slide information as the weight information of the vehicle <NUM> decreases.

The wheel slide predicting unit <NUM> also corrects the wheel slide likelihood score for each candidate predicted wheel slide position, in accordance with the current weather information and the current state of the vehicle <NUM>. More specifically, the wheel slide predicting unit <NUM> performs the correction such that the wheel slide likelihood score calculated for each candidate predicted wheel slide position increases as the precipitation indicated by the current weather information increases. Furthermore, the wheel slide predicting unit <NUM> performs the correction such that the wheel slide likelihood score calculated for each candidate predicted wheel slide position increases as the total weight Y1 of the vehicle body <NUM> of the current vehicle <NUM> increases. In addition, the wheel slide predicting unit <NUM> performs the correction such that the wheel slide likelihood score calculated for each candidate predicted wheel slide position increases as the largest value of the four values of the axial rotational speed X2 of the current vehicle <NUM> increases.

Once the wheel slide likelihood score is calculated for each candidate predicted wheel slide position in the above-described manner, the wheel slide predicting unit <NUM> identifies, as the predicted wheel slide position, the candidate predicted wheel slide position having a wheel slide likelihood score of a predetermined reference value or more. After this, the control device <NUM> proceeds to a step S63.

In the step S63, the wheel slide predicting unit <NUM> in the control device <NUM> determines whether the predicted wheel slide position is ahead in the traveling direction of the vehicle <NUM>. When determining that no predicted wheel slide positions are ahead in the traveling direction of the vehicle <NUM> in the step S63 (S63: NO), the control device <NUM> terminates the current series of controls to predict wheel slide. On the other hand, when determining that one or more predicted wheel slide positions are ahead in the traveling direction of the vehicle <NUM> in the step S63 (S63: YES), the control device <NUM> proceeds to a step S64.

In the step S64, the distance determining unit <NUM> in the control device <NUM> calculates a reach distance between the current position of the vehicle <NUM> on the rail and the predicted wheel slide position ahead in the traveling direction of the vehicle <NUM>. In order to calculate the reach distance, the distance determining unit <NUM> calculates the speed of the vehicle <NUM> based on the axial rotational speed X2 and uses the calculated speed to calculate the current position of the vehicle <NUM> as described above. The distance determining unit <NUM> then uses the current position of the vehicle <NUM> on the rail and the predicted wheel slide position ahead in the traveling direction of the vehicle <NUM> to calculate the reach distance between these positions. When there are a plurality of predicted wheel slide positions, the distance determining unit <NUM> calculates the reach distance for each of the predicted wheel slide positions. After this, the control device <NUM> proceeds to a step S65.

In the step S65, the distance determining unit <NUM> in the control device <NUM> determines whether the shortest reach distance is equal to or less than a predetermined distance. The predetermined distance is, for example, several kilometers. When determining that the shortest reach distance is equal to or less than the predetermined distance in the step S65 (S65: YES), the distance determining unit <NUM> in the control device <NUM> proceeds to a step S71.

In the step S71, the control device <NUM> calculates the current speed of the vehicle <NUM>. More specifically, the control device <NUM> calculates the speed of the vehicle <NUM> based on the largest value of the four values of the axial rotational speed X2 in the vehicle <NUM>. After this, the control device <NUM> proceeds to a step S72.

In the step S72, the brake control unit <NUM> in the control device <NUM> sets the upper limit of the deceleration rate of the vehicle <NUM> at a predetermined deceleration rate. Here, the deceleration rate is the negative acceleration rate while the speed of the vehicle <NUM> is reduced and calculated as a positive value in the present embodiment. In order to determine the predetermined deceleration rate, experiments or the like are performed to obtain the deceleration rate of the vehicle <NUM> achieved by the brake control instructed by the highest brake instruction X6 under the assumption that the vehicle <NUM> is traveling on a rail with a gradient less than a predetermined value and the obtained deceleration rate is set as the highest deceleration rate. The predetermined deceleration rate is lower than the highest deceleration rate by approximately several dozen %. After this, the control device <NUM> proceeds to a step S73.

In the step S73, the report control unit <NUM> in the control device <NUM> causes the display <NUM> to display that the predicted wheel slide position is present in the vicinity of the vehicle <NUM> ahead in the traveling direction of the vehicle <NUM>. The report control unit <NUM> also causes the display <NUM> to display that the upper limit of the deceleration rate of the vehicle <NUM> is set at the predetermined deceleration rate. The report control unit <NUM> causes the display <NUM> of only the vehicle 10A at the front to display a variety of information. After this, the control device <NUM> proceeds to a step S74.

In the step S74, the control device <NUM> determines whether the current speed of the vehicle <NUM> is higher than a predetermined speed. The speed of the vehicle <NUM> observed when the wheels <NUM> of the vehicle <NUM> slide depends on various conditions. For the speed of the vehicle <NUM> observed when the wheels <NUM> of the vehicle <NUM> have slid, a large number of values are in advance measured under all conditions. In the present embodiment, the predetermined speed is set at a value lower than the average of the measured speed values by approximately several dozen %. When determining that the current speed of the vehicle <NUM> is higher than the predetermined speed in the step S74 (S74: YES), the control device <NUM> proceeds to a step S81.

In the step S81, the brake control unit <NUM> in the control device <NUM> performs deceleration control to reduce the speed of the vehicle <NUM>. More specifically, the brake control unit <NUM> reduces the speed of the vehicle <NUM> by controlling the brake devices <NUM> such that the braking force produced by the brake devices <NUM> is larger, by a predetermined reference braking force, than the braking force provided by the brake device <NUM> in accordance with the brake instruction X6. Here, the brake control unit <NUM> reduces the speed of the vehicle <NUM> to such an extent that the deceleration rate of the vehicle <NUM> does not exceed the predetermined deceleration rate. The control in the step S81 may be repeatedly performed multiple rounds, but the braking force provided by the brake devices <NUM> is larger by the reference braking force only in the first round of the step S81. The speed of the vehicle <NUM> makes a transition to be equal to or fall below the predetermined speed as the deceleration control is continuously performed while the series of controls to predict wheel slide are repeatedly performed. The report control unit <NUM> in the control device <NUM> causes the display <NUM> to display that the deceleration control is being in process. The report control unit <NUM> causes the display <NUM> of only the vehicle 10A at the front to display this information. After this, the control device <NUM> terminates the current series of controls to determine wheel slide.

When determining that the shortest reach distance is longer than the predetermined distance in the above-described step S65 (S65: NO), the control device <NUM> proceeds to a step S66. In the step S66, the brake control unit <NUM> in the control device <NUM> removes the upper limit set on the deceleration rate in the step S72 of the immediately prior or any of previous series of controls to predict wheel slide. If no upper limit is set on the deceleration rate at the time of performing the step S66, the brake control unit <NUM> continuously maintains the state where no upper limit is set on the deceleration rate. After this, the control device <NUM> terminates the current series of controls to predict wheel slide.

When determining that the current speed of the vehicle <NUM> is equal to or less than the predetermined speed in the above-described step S74 (S74: NO), the control device <NUM> proceeds to a step S82. In the step S82, the brake control unit <NUM> in the control device <NUM> terminates the deceleration control, which is started in the step S81 of the immediately prior or any of previous series of controls to predict wheel slide. More specifically, the brake control unit <NUM> controls the brake devices <NUM> such that the braking force produced by the brake devices <NUM> becomes equal to the braking force provided by the brake devices <NUM> in accordance with the brake instruction X6. If no deceleration control is performed at the time of perming the step S82, the brake control unit <NUM> continuously maintains the state where no deceleration control is performed. After this, the control device <NUM> terminates the current series of controls to predict wheel slide.

Regarding the above-described controls to determine wheel slide and to predict wheel slide, the following summarizes how the variety of information are exchanged and the controls are configured. As shown in <FIG>, the controls to determine wheel slide generates the wheel slide information of the vehicle <NUM> by associating a variety of information acquired when the wheels <NUM> of the vehicle <NUM> have slid with the fact that the wheels <NUM> of the vehicle <NUM> have slid. In other words, the wheel slide information includes information acquired when it was determined in the past that the wheels <NUM> of the vehicle <NUM> slid. The controls to predict wheel slide calculates a predicted wheel slide position where the wheels <NUM> of the vehicle <NUM> may possibly slide in the future, based on the previous wheel slide information and current variety of information.

The following describes how the first embodiment produces effects.

If the wheels <NUM> of the vehicle <NUM>, which travels on a rail, slide, the control device <NUM> performs the controls to determine wheel slide and determines that wheel slide occurs, and stores wheel slide information including the position information indicative of the position of the vehicle <NUM> on the rail where the wheels <NUM> have slid. Every time the wheels <NUM> of the vehicle <NUM> slide, wheel slide information is stored and accumulated in the storing unit <NUM> of the control device <NUM>.

If the vehicle <NUM> is traveling with at least one piece of wheel slide information being stored in the storing unit <NUM> of the control device <NUM>, the control device <NUM> calculates a predicted wheel slide position based on the wheel slide information. The position where the wheels <NUM> have slid, which is included in the wheel slide information, is used as a candidate predicted wheel slide position, and wheel slide likelihood score is calculated for the candidate predicted wheel slide position. In this way, for each of the candidate predicted wheel slide positions, the wheel slide likelihood score is calculated based on the state of the vehicle <NUM> at the time of the previous occurrence of wheel slide.

The control device <NUM> also corrects the wheel slide likelihood score for each candidate predicted wheel slide position, in accordance with the current state of the vehicle <NUM>. More specifically, for example, if no precipitation is observed now, the wheel slide likelihood score is corrected to be lower. If the precipitation is more than zero, the wheel slide likelihood score is corrected to be higher. If any of the candidate predicted wheel slide positions have a wheel slide likelihood scores equal to or higher than a reference value, the candidate predicted wheel slide position in question is identified as the predicated wheel slide position. The wheel slide likelihood score for the same candidate predicted wheel slide position may vary depending on the current state of the vehicle <NUM>. This means that a candidate predicted wheel slide position may be identified as a predicted wheel slide position or not depending on the current state of the vehicle <NUM>.

It is assumed that the vehicle <NUM> is traveling and a predicted wheel slide position is ahead in the traveling direction of the vehicle <NUM>. In this case, as the distance between the vehicle <NUM> and the predicted wheel slide position decreases, the upper limit of the deceleration rate of the vehicle <NUM> is set at the predetermined deceleration rate. In addition, the display <NUM> of the vehicle <NUM> displays that the predicted wheel slide position is near and that an upper limit is set on the deceleration rate. For example, if the driver of the vehicle <NUM> looks at what is displayed on the display <NUM>, the driver may refrain from suddenly braking the vehicle <NUM>. In this way, the deceleration rate of the vehicle <NUM> is highly likely to fall below the upper limit of the deceleration rate of the vehicle <NUM>. On the other hand, if the driver of the vehicle <NUM> misses what is displayed on the display <NUM>, the driver may attempt to suddenly brake the vehicle <NUM>. Even if this happens, the deceleration rate of the vehicle <NUM> is limited to fall below the predetermined deceleration rate. Accordingly, the vehicle <NUM> is not actually suddenly braked in the case where the predicted wheel slide position is near.

If the driver of the vehicle <NUM> misses what is displayed on the display <NUM> and is not aware of the fact that the vehicle <NUM> is traveling near the predicted wheel slide position, the driver may possibly fail to decelerate the vehicle <NUM> and intend to keep traveling. In this case, if the speed of the vehicle <NUM> exceeds the predetermined speed, the braking force produced by the brake devices <NUM> increases to such an extent that the deceleration rate of the vehicle <NUM> does not exceed the predetermined deceleration rate. Accordingly, the speed of the vehicle <NUM> is gradually reduced before the vehicle <NUM> arrives at the predicted wheel slide position.

Advantageous effects of the first embodiment will be now described.

The following describes a second embodiment, not according to the claimed invention but supporting its disclosure, with reference to <FIG>. In the following description of the second embodiment, the differences between the first and second embodiments are mainly discussed. The same elements as in the first embodiment will be denoted by the same reference numerals and descriptions thereof will be omitted or only briefly mentioned.

As shown in <FIG>, the control device <NUM> is capable of communicating with a server <NUM> via the external communication line network <NUM>. The server <NUM> is also capable of communicating with the weather service center <NUM> via the external communication line network <NUM>.

In the second embodiment, the control device <NUM> includes the brake control unit <NUM> and the report control unit <NUM>. On the other hand, the server <NUM> includes a wheel slide determining unit <NUM> for determining whether the wheels <NUM> of the vehicle <NUM> are sliding. In addition, the server <NUM> includes a storing unit <NUM> for storing the wheel slide information of the vehicle <NUM>. The server <NUM> also includes a generating unit <NUM> for generating the wheel slide information. The server <NUM> further includes a wheel slide predicting unit <NUM> for calculating a predicted wheel slide position where the wheels <NUM> of the vehicle <NUM> may possibly slide. The server <NUM> further includes a distance determining unit <NUM> for calculating a reach distance between the position of the vehicle <NUM> on the rail and the predicted wheel slide position ahead in the traveling direction of the vehicle <NUM>. The server <NUM> additionally includes an acquiring unit <NUM> for acquiring position information of the vehicle <NUM> on the rail. In the second embodiment, the wheel slide determining unit <NUM>, storing unit <NUM>, generating unit <NUM>, wheel slide predicting unit <NUM>, distance determining unit <NUM> and acquiring unit <NUM> of the server <NUM> have the same capabilities as the wheel slide determining unit <NUM>, storing unit <NUM>, generating unit <NUM>, wheel slide predicting unit <NUM>, distance determining unit <NUM> and acquiring unit <NUM> of the control device <NUM> relating to the first embodiment. As the server <NUM> includes the wheel slide determining unit <NUM>, storing unit <NUM> and acquiring unit <NUM>, the server <NUM> partially serves as a wheel slide information generating device. As the server <NUM> includes the wheel slide determining unit <NUM>, storing unit <NUM>, wheel slide predicting unit <NUM> and acquiring unit <NUM> and the control device <NUM> includes the report control unit <NUM>, a system integrating together the server <NUM> and the control device <NUM> as a whole serves as a wheel slide predicting device. As the control device <NUM> includes the brake control unit <NUM>, a system integrating together the server <NUM> and the control device <NUM> as a whole serves as a control device for a brake device, which can serve as a wheel slide predicting device.

In the second embodiment, the server <NUM> repeatedly performs the same series of controls to determine wheel slide as in the first embodiment while the vehicle <NUM> is traveling. The server <NUM> communicates with the control device <NUM> of the vehicle <NUM> at predetermined time intervals, so that the server <NUM> collects the axial rotational speed X2 of the vehicle <NUM>, brake instruction X6 and the total weight Y1 of the vehicle <NUM>.

The server <NUM> and control device <NUM> repeatedly perform the same series of controls to predict wheel slide as in the first embodiment while the vehicle <NUM> is traveling. The steps S61 to S66 and S71 included in the wheel slide prediction controls are performed by the server <NUM>. In the steps S61, S64 and S71, the server <NUM> communicates with the control device <NUM> of the vehicle <NUM>, to collect the axial rotational speed X2 of the vehicle <NUM>, brake instruction X6 and total weight Y1 of the vehicle <NUM>. The server <NUM> then uses the collected variety of information to perform the respective steps. In the step S65, the server <NUM> communicates with the control device <NUM> of the vehicle <NUM>, to instruct the brake control unit <NUM> of the vehicle <NUM> to set an upper limit on the deceleration rate. In the step S66, the server <NUM> communicates with the control device <NUM> of the vehicle <NUM>, to instruct the brake control unit <NUM> of the vehicle <NUM> to remove the upper limit set on the deceleration rate. On the other hand, the steps S72 to S82 included in the wheel slide prediction controls are performed by the control device <NUM>.

Accordingly, the second embodiment can produce the advantageous effects (<NUM>) to (<NUM>) described above, which are produced also by the first embodiment. The second embodiment additionally provides the following advantageous effects.

The foregoing embodiments can be modified as described below. The above embodiments and the following modifications can be combined with each other as long as they are technically consistent with each other.

In the above embodiments, the deceleration control can be modified. For example, the brake devices <NUM> may be controlled such that the brake devices <NUM> may provide braking force of a constant magnitude, irrespective of the position of the lever of the brake controller <NUM> resulting from the operation of the lever.

In the controls to predict wheel slide, the deceleration control in the step S81 may be skipped. For example, skipping the deceleration control does not cause any special problems when the calculated predicted wheel slide position Is present In an area where the speed of the vehicle <NUM> is not likely to become too high under normal travel conditions, for example, a curve with a large curvature.

In the controls to predict wheel slide, the predetermined deceleration rate in the step S72 may not be constant and depend on the speed of the vehicle <NUM>. The predetermined deceleration rate may be variable but can be considered to be set in advance any way if calculating formulas, maps and the like are prepared in advance to calculate the predetermined deceleration rate.

In controls to predict wheel slide not according to the invention, the setting of an upper limit on the deceleration rate in the step S72 may be skippad. For example, skipping the setting of an upper limit on the deceleration rate does not cause any special problems when the calculated predicted wheel slide position is present in an area where the deceleration rate of the vehicle <NUM> Is not likely to become too high under normal travel conditions, for example, an ascending slope.

In the controls to predict wheel slide, the reporting in the step S73 may be skipped. For example, when the vehicle <NUM> is self-driven without a human, it is hardly required to issue a report on the display <NUM> of the vehicle <NUM>.

The wheel slide information generated by the control device <NUM> of the vehicle <NUM> and the predicted wheel slide position calculated based on the wheel slide information may be transmitted to and shared with other vehicles. For example, if the wheels <NUM> of the vehicle <NUM> of the train <NUM> slide, the wheel slide information and the predicated wheel slide position may be transmitted to the vehicles of a later train on the same route. In this way, the vehicles of the later train can know the predicted wheel slide position even if no wheel slide occurs for the wheels of the later train.

In the controls to predict wheel slide, the calculation of the predicted wheel slide position in the step S62 can be modified. For example, the correction of the wheel slide likelihood score based on the current state of the vehicle <NUM> and the current weather information may be skipped. As another example, the calculation of the wheel slide likelihood score based on the wheel slide information may be omitted. More specifically, for example, the wheel slide likelihood score is not calculated and all of the positions stored as the wheel slide information may be treated as predicted wheel slide positions.

In the above first embodiment, the controls to predict wheel slide may be skipped. Even in this case, the wheel slide information is generated in the controls to determine wheel slide, and the generated wheel slide information is stored in the storing unit <NUM>. An operator can aggregate the wheel slide information stored in the storing unit <NUM> and calculate the predicted wheel slide position.

In the controls to determine wheel slide, the information included in the wheel slide information can be modified as appropriate. The predicted wheel slide position can be predicted as long as the wheel slide information at least includes the position information associating the position of the vehicle <NUM> on the rail when the wheels <NUM> have slid with the fact that the wheels <NUM> of the vehicle <NUM> have slid. Alternatively, the wheel slide information may include another information other than the items illustrated in the above-described embodiments. The other information that can be included in the wheel slide information can be, for example, the date and time when the wheels <NUM> have slid, the temperature observed when the wheels <NUM> have slid, which is part of the weather information. The information indicating the deceleration is not limited to the brake instruction X6. For example, the information indicating the deceleration may be the deceleration rate of the vehicle <NUM> or the deceleration rate of the entire train <NUM>.

Claim 1:
A device (<NUM>) for use with a railroad vehicle (<NUM>), the device (<NUM>) comprising:
processing circuitry (<NUM>, <NUM>-<NUM>, <NUM>); and
a memory (<NUM>) coupled to the processing circuitry (<NUM>, <NUM>-<NUM>, <NUM>);
wherein the processing circuitry (<NUM>, <NUM>-<NUM>, <NUM>) is configured to:
acquire position information of a railroad vehicle (<NUM>) on a rail;
determine, based on a rotational speed (X2) of a wheel (<NUM>) of the railroad vehicle (<NUM>), whether the wheel (<NUM>) is sliding; and
store in the memory (<NUM>), as wheel slide information, position information of the railroad vehicle (<NUM>) on the rail observed when the wheel (<NUM>) has slid
characterized in that
the processing circuitry (<NUM>, <NUM>-<NUM>, <NUM>) is further configured to:
calculate, based on the wheel slide information, a predicted wheel slide position where the wheel (<NUM>) possibly slides; and
control a brake device (<NUM>) of the railroad vehicle (<NUM>) such that a deceleration rate of the railroad vehicle (<NUM>) observed when the railroad vehicle (<NUM>) is on the predicted wheel slide position is equal to or less than a predetermined deceleration rate.