JP2017099607A - Step detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a step detection device capable of highly accurately detecting a step on a road surface.SOLUTION: The step detection device includes: a pitch rate acquisition part 11 for acquiring a first pitch rate when front wheels 101 of a wheel chair 100 pass through a travel surface, and a second pitch rate when rear wheels 102 of the wheelchair 100 pass through the position where the first pitch rate is acquired; a correction part 12 for correcting the first pitch rate and the second pitch rate acquired by the pitch rate acquisition part 11, by a travel speed of the wheelchair 100; and a step detection part 13 for detecting a step on the basis of a first pitch change and a second pitch change as results corrected by the correction part 12.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a level difference detection device that detects a level difference on a running surface.

  A barrier-free map has been created that shows the steps on the running surface and the like, and displays easily accessible routes for wheelchair users. Such a barrier-free map is manually surveyed for steps, etc., and it takes labor, time and cost. Therefore, the barrier-free map has been created only in some cities.

  In addition, it is difficult to frequently update the barrier-free map for manual investigation. For this reason, for example, a change in the state of the traveling surface such as road construction may not be reflected in the barrier-free map, and may be far from the actual state of the traveling surface.

  In response to such a problem, an apparatus for automatically detecting a step or the like has been proposed. For example, in Patent Document 1, the angular velocity sensor of the portable terminal detects the angular velocity while the user is walking and compares it with the angular velocity data of a flat place stored in advance. However, it is described that the information and position of the step are transmitted to the center.

  Further, in Patent Document 2, when the road angle of the road on which the vehicle calculated by the 3D gyroscope is larger than a predetermined value, it is determined as a steep step and a point determined as a step can be registered. Have been described.

  Patent Document 3 describes that a wheelchair is provided with vibration detection means and inclination detection means, and road surface irregularities and inclinations when moved are uploaded to a server together with position information.

JP 2012-098939 A Japanese Patent Laying-Open No. 2005-043261 JP 2003-010257 A

  The method described in Patent Document 1 can detect a step that is continuous or has a large difference in height, such as a staircase, but in the case of a small step, a pedestrian can exceed this by a single step. Therefore, it may not be detected. In the case of the method described in Patent Document 2, since the step and the slope are distinguished by the magnitude of the gradient angle, it is difficult to accurately detect a step having a small gradient angle and a relatively low height. As described above, in the methods described in these documents, it is difficult to accurately detect a step that becomes a barrier for a wheelchair or the like even if the step has no problem for a pedestrian.

  Moreover, although the method of patent document 3 is disclosed that the unevenness | corrugation state of a running surface is detected by a vibration detection means, the concrete method of detecting a level | step difference is not disclosed at all. Therefore, it cannot be distinguished whether the detected point is uneven or stepped.

  In view of the above-described problems, an object of the present invention is to provide a level difference detection device that can detect a level difference on a traveling surface with high accuracy.

  In order to solve the above problems, the invention according to claim 1 is characterized in that an acquisition means for acquiring a pitch change which is a change in pitch angle per unit moving distance of a moving body, and i) traveling acquired by the acquisition means. A first pitch change when the front wheel of the moving body passes on the surface, and ii) a second pitch change when the rear wheel of the moving body passes the position where the first pitch change is acquired. And a step detecting means for detecting a step based on the step detecting device.

  The invention according to claim 6 is an acquisition step of acquiring a pitch change which is a change in pitch angle per unit moving distance of the moving body, and i) acquired in the acquisition step, i) on the traveling surface, the moving body A step difference is detected based on a first pitch change when the front wheel of the vehicle has passed, and ii) a second pitch change when the rear wheel of the moving body passes through the position where the first pitch change is acquired. And a step detection step.

  A seventh aspect of the invention is a step detection program that causes a computer to execute the step detection method according to the sixth aspect.

  The invention described in claim 8 is a computer-readable recording medium in which the step detection program according to claim 7 is stored.

It is a schematic block diagram of the level | step difference detection system which has the level | step difference detection apparatus concerning one Example of this invention. It is a schematic block diagram of the arithmetic unit etc. which were shown by FIG. It is a schematic block diagram of the server apparatus shown by FIG. It is explanatory drawing which showed the state of the movement of the wheelchair in the case of an uphill step. It is the graph which showed the change of the pitch rate in the state of FIG. 4, and a pitch angle. It is explanatory drawing which showed the state of the movement of the wheelchair in the case of a descent | fall level | step difference. It is the graph which showed the change of the pitch rate in the state of FIG. 6, and a pitch angle. It is the graph which showed the relationship between the running speed of a wheelchair, and a pitch rate. FIG. 9 is a graph after the pitch rate shown in FIG. 8 is corrected to a change in pitch according to a traveling speed. It is the graph which set the threshold value to pitch change. It is explanatory drawing that the riding angle to a level | step difference differs when a front-wheel diameter and a rear-wheel diameter differ. It is a graph at the time of changing a threshold value with a front wheel and a rear wheel. It is the graph which showed the relationship between the pitch change and threshold value when there are inclined surfaces before and after the step. It is the graph which showed changing a threshold value when there exists an inclined surface before and behind a level | step difference. It is a flowchart of the level | step difference detection method of the arithmetic unit shown in FIG. It is explanatory drawing which showed the relationship between the height of a level | step difference, and a pitch angle. An example in the case where there is an inclination and a step and a graph of the change in the pitch angle, an example of only the inclination (no step) and a graph in the change of the pitch angle It is a schematic explanatory drawing of the estimation method of the level difference in a present Example. It is the graph which showed the specific example of the level difference estimation method shown in FIG. It is a flowchart of the level | step difference estimation method of the arithmetic unit shown in FIG. It is a flowchart of the statistical processing method of the step height estimated in FIG.

  Hereinafter, the level | step difference detection apparatus concerning one Embodiment of this invention is demonstrated. In the level difference detection apparatus according to an embodiment of the present invention, the acquisition unit acquires a pitch change that is a change in pitch angle per unit moving distance of the moving body. And the step detection means acquired by the acquisition means i) the first pitch change when the front wheel of the moving body passes on the traveling surface, and ii) the position where the first pitch change was acquired is the rear wheel of the moving body. The step is detected based on the second pitch change at the time of passing. By doing in this way, a level difference can be detected without depending on the traveling speed of the moving body. Therefore, the step on the road surface can be detected with high accuracy even if the step is relatively low.

  The acquisition unit may acquire the pitch change by correcting a pitch rate, which is a change per unit time, of the pitch angle of the moving body based on the traveling speed of the moving body. By doing so, it is possible to detect the step without depending on the speed by correcting the pitch rate of the two wheels of the front wheel and the rear wheel by the speed. Therefore, the step on the road surface can be detected with high accuracy even if the step is relatively low.

  Further, the step detecting means has an absolute value of the first pitch change corrected by the correcting means equal to or greater than a predetermined first threshold, and an absolute value of the second pitch change corrected by the correcting means is predetermined. If it is equal to or greater than the second threshold, the position may be detected as a step. By doing in this way, it is possible to make a step difference when a pitch rate having an absolute value greater than a certain value is detected when the front wheel passes and when the rear wheel passes, so that the step can be detected with high accuracy.

  Further, the step detecting means changes from the average value of the pitch change to the second pitch change after the absolute value of the first pitch change becomes greater than or equal to a predetermined first threshold value and then becomes less than the first threshold value. The absolute value of the quantity may be compared with a predetermined second threshold value. By doing so, for example, when there is an inclination before and after the step and the pitch change fluctuates due to the influence of the inclination, erroneous detection of the second pitch change can be prevented.

  Further, the wheel diameters of the front wheels and the rear wheels may be different, and the first threshold value and the second threshold value are set to be smaller as the wheel diameter is larger. Even when the wheel diameter is smaller than the wheel diameter, the level difference can be detected with high accuracy.

  Moreover, the level | step difference detection method concerning one Embodiment of this invention acquires the pitch change which is a change of the pitch angle per unit moving distance of a moving body at an acquisition process. And the acquisition means acquired in the step detection step i) the first pitch change when the front wheel of the moving body passes on the traveling surface, and ii) the position where the first pitch change was acquired is the rear wheel of the moving body. The step is detected based on the second pitch change at the time of passing. By doing in this way, a level difference can be detected without depending on the traveling speed of the moving body. Therefore, the step on the road surface can be detected with high accuracy even if the step is relatively low.

  Moreover, it is good also as a level | step difference detection program which performs the level | step difference detection method mentioned above by computer. By doing so, it is possible to detect a step using a computer without depending on the speed. Therefore, the step on the road surface can be detected with high accuracy even if the step is relatively low.

  Further, the step detection program described above may be stored in a computer-readable recording medium. In this way, the program can be distributed as a single unit in addition to being incorporated in the device, and version upgrades can be easily performed.

  A step detection device according to an embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the computing device 1 as a step detection device according to the present embodiment is mounted on a wheelchair 100 as a moving body.

  FIG. 1 is a configuration diagram of a step detection system having a step detection device according to an embodiment of the present invention. As shown in FIG. 1, the wheelchair 100 includes a GPS receiver 2, a speed sensor 3 as a speed detection unit, a gyro sensor 4 as a pitch rate detection unit, and a transmission unit in addition to the arithmetic device 1. The communication device 5 is mounted.

  The communication device 5 mounted on the wheelchair 100 can be connected to a network network N such as the Internet by wireless communication, and can communicate with the server device 50 via the network network N.

  The wheelchair 100 is provided with a pair of left and right front wheels 101 and a pair of left and right rear wheels 102 on the vehicle body. The front wheel 101 is provided on the front side of the vehicle body. The rear wheel 102 is provided on the rear side of the vehicle body. The front wheel 101 is smaller in diameter than the rear wheel 102.

  The vehicle body of the wheelchair 100 is a frame structure composed of a steel pipe frame, for example. The vehicle body is provided with a seat on which the user is seated, a foot plate on which the user's feet are placed, and the like.

  The functional block diagram of the apparatus mounted in the wheelchair 100 is shown in FIG. The arithmetic unit 1 includes, for example, a microcomputer including a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory), a GPS receiver 2, an acceleration sensor 3, a gyro sensor 4, An interface for connecting to the communication device 5 is provided. In addition, the arithmetic device 1 executes a control program stored in a ROM or the like, whereby a pitch rate acquisition unit 11 as an acquisition unit, a correction unit 12 as a correction unit, and a step detection unit 13 as a step detection unit. And function.

  The pitch rate acquisition unit 11 acquires the pitch rate detected by the gyro sensor 4 and the like. Moreover, the pitch rate acquisition part 11 acquires the pitch rate acquired when it met the conditions mentioned later as a 1st pitch rate and a 2nd pitch rate.

  The correction unit 12 corrects the first pitch rate and the second pitch rate acquired by the pitch rate acquisition unit 11 based on the speed of the wheelchair 100 detected by the speed sensor 3.

  The level difference detection unit 13 detects a level difference on the road surface (traveling surface) based on the result of the correction unit 12 correcting the first pitch rate and the second pitch rate. The step detection method will be described later. Here, the correction of the first pitch rate is referred to as a first pitch change, and the correction of the second pitch rate is referred to as a second pitch change. The traveling surface is a ground surface, a floor surface, or the like on which a moving body having a roadway, a sidewalk, and other front wheels and rear wheels can travel, whether indoors or outdoors. That is, the level difference detection unit 13 functions as a level difference detection unit that detects a level difference on the traveling surface on which the mobile body (wheelchair 100) has traveled and passed based on the acquired and corrected values. In addition, the level | step difference in a present Example is a position (point) where it becomes difficult to go up or down with the wheelchair 100 on a running surface, Comprising: One running surface and the next running surface are more than predetermined height. A position that is connected by a vertical plane or a slope with a predetermined angle or more.

  As is well known, the GPS receiver 2 receives radio waves transmitted from a plurality of GPS (Global Positioning System) satellites, obtains current location information (latitude, longitude), and outputs the current location information (latitude, longitude) to the computing device 1.

  The speed sensor 3 detects the speed (travel speed) at which the wheelchair 100 travels. For example, the speed sensor 3 may be detected from the rotational speed of the rear wheel 102 or may be detected from the rotational speed of the motor in the case of an electric wheelchair.

  The gyro sensor 4 acquires the rotational angular velocity (pitch rate) of the wheelchair 100 in the pitch direction. Here, the pitch indicates an inclination in the vertical direction with respect to the traveling direction of the wheelchair 100 (a rotation angle about the horizontal direction). The gyro sensor 4 may be any type of sensor such as a capacitance type or a piezoelectric type, but is preferably small because it is mounted on the wheelchair 100.

  The communication device 5 transmits the result calculated by the calculation device 1 to the server device 50 by wireless communication. The communication device 5 may be a communication method used in a mobile phone network such as LTE (Long Term Evolution) or W-CDMA (Wideband Code Division Multiple Access). In addition, a wireless LAN communication method such as Wi-Fi (registered trademark) may be used, or those may be switched and used.

  A functional configuration diagram of the server device 50 is shown in FIG. The server device 50 includes a communication device 51, an arithmetic device 52, and a storage device 53. The communication device 51 receives the result calculated by the calculation device 1 transmitted from the communication device 5.

  The arithmetic device 52 includes a microcomputer including a memory such as a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory). The arithmetic device 52 functions as a level determination unit 521 and an update unit 522 by executing a control program stored in a ROM or the like.

  The level determination unit 521 determines the level of the step difference in height based on the information transmitted from the arithmetic device 1. The level of the level difference is obtained by dividing the level of the level difference by level. For example, 0 cm or more and less than 5 cm is determined based on a predetermined threshold such as level 1 and level 5 or more and less than 10 cm.

  The update unit 522 updates the barrier information of the map information 532 stored in the storage device 53 based on the determination result of the level determination unit 521. In addition, the update unit 522 accumulates an average for each point (for each position) of information such as a step height transmitted from the computing device 1 as average height information 531.

  Next, the principle of detecting the level difference in this embodiment will be described with reference to FIGS. FIG. 4 is a diagram illustrating a state of movement of the wheelchair 100 when passing through the ascending step U, and FIG. 5 is a graph illustrating changes in pitch rate and pitch angle in the state of FIG.

  First, the state of FIG. 4A is a state before passing through the upstep U. In this case, neither the pitch rate nor the pitch angle changes significantly (a in FIG. 5A). Next, the state of FIG. 4B is a state in which the front wheel 101 goes up the ascending step U. In this case, since the front wheel 101 goes up the ascending step U, the vehicle body of the wheelchair 100 becomes obliquely upward in the traveling direction, and the pitch rate increases upward (b in FIG. 5A).

  Next, the state of FIG. 4C is a state in which the rear wheel 102 goes up the ascending step U. In this case, since the rear wheel 102 goes up the ascending step U, the body of the wheelchair 100 increases in a downward direction so as to shift from an oblique state to a horizontal state (c in FIG. 5A). And the state of FIG.4 (d) is a state after passing the uphill level | step difference U. FIG. In this case as well, the pitch rate and the pitch angle do not change significantly as before passing through the upward step U (d in FIG. 5A).

  That is, in the case of the up step U, when the front wheel 101 passes through the up step U, the pitch rate increases in the + direction. That is, the pitch rate is a positive number. When the rear wheel 102 passes through the ascending step U, the pitch rate increases in the negative direction. That is, the pitch rate is a negative number. Here, the pitch rate of the present embodiment becomes a positive number when the vehicle body tilts so that the wheelchair 100 rises with respect to the traveling direction, and becomes a negative number when the vehicle body tilts so as to fall with respect to the traveling direction.

  FIG. 6 is a diagram showing a state of movement of the wheelchair 100 when passing through the descending step D, and FIG. 7 is a graph showing changes in pitch rate and pitch angle in the state of FIG.

  First, the state of FIG. 6A is a state before passing through the descending step D. In this case, neither the pitch rate nor the pitch angle changes significantly (a in FIG. 7A). Next, the state of FIG. 6B is a state in which the front wheel 101 descends the descending step D. In this case, since the front wheel 101 goes down the descending step D, the vehicle body of the wheelchair 100 becomes obliquely downward in the traveling direction, and the pitch rate increases downward (b in FIG. 7A).

  Next, the state of FIG. 6C is a state in which the rear wheel 102 descends the descending step D. In this case, since the rear wheel 102 goes down the descending step D, the vehicle body of the wheelchair 100 increases upward in an attempt to shift from an oblique state to a horizontal state (c in FIG. 7A). The state shown in FIG. 6D is a state after passing through the descending step D. In this case as well, the pitch rate and the pitch angle do not change significantly as before passing through the descending step D (d in FIG. 7A).

  That is, in the case of the descending step D, when the front wheel 101 passes the descending step D, the pitch rate increases in the − direction. That is, the pitch rate is a negative number. When the rear wheel 102 passes the descending step D, the pitch rate increases in the + direction. That is, the pitch rate is a positive number.

  Therefore, according to FIGS. 4 to 7, it is possible to detect whether the vehicle has passed the up step U or the down step D based on the value and sign of the pitch rate detected by the gyro sensor 4. In addition, by providing a threshold value for the detected pitch rate, it is possible to reliably detect a peak that appears when a step such as point b or point c shown in FIGS. 5 and 7 is passed.

  Here, the relationship between the running speed of the wheelchair 100 and the pitch rate will be described with reference to FIG. FIG. 8 is a graph showing changes in the pitch rate when the traveling speed is changed. 8A shows a case where the traveling speed of the wheelchair 100 is 2.5 km / h, FIG. 8B shows a case where the traveling speed of the wheelchair 100 is 4.5 km / h, and FIG. A case where the traveling speed of 100 is 6.0 km / h is shown. As shown in FIG. 8, the higher the traveling speed, the larger the change per unit time, so that the pitch rate peak becomes larger. At this time, when a threshold value or the like is set in order to determine the level difference, it is necessary to set it according to the traveling speed. However, a plurality of threshold values or the like must be properly used according to the speed, and the processing becomes complicated.

  Therefore, in this embodiment, in order to eliminate the difference due to the speed, the pitch rate value is corrected by being divided by the traveling speed. FIG. 9 shows the result of correcting FIG. 9A shows a case where the traveling speed of the wheelchair 100 is 2.5 km / h, FIG. 9B shows a case where the traveling speed of the wheelchair 100 is 4.5 km / h, and FIG. A case where the traveling speed of 100 is 6.0 km / h is shown. As shown in FIG. 9, by dividing and correcting the pitch rate value by the traveling speed, it can be converted into a pitch change with respect to the position, and the same pitch change can be obtained regardless of the speed. Therefore, the step can be determined from the magnitude of the pitch change without considering the speed. 8 and 9 have been described by taking the ascending step as an example, it goes without saying that the same applies to the descending step. In this embodiment, the pitch change is calculated by correcting the pitch rate, but the pitch change may be acquired by other methods. As an example, the pitch change may be calculated by detecting the pitch angle and the moving distance and dividing the pitch angle by the unit distance.

  The thresholds for determining the step are preferably provided on both the front wheel 101 side and the rear wheel 102 side. That is, two thresholds, a positive value and a negative value, may be prepared. This is because, as shown in FIGS. 5 and 7, the polarity of the pitch change is opposite between the front wheel 101 side and the rear wheel 102 side. Further, as shown in FIG. 10, the pitch change becomes larger as the step height is higher. 10A shows a case where the step is 10 mm, FIG. 10B shows a case where the step is 20 mm, and FIG. 10C shows a case where the step is 30 mm. Therefore, in order to detect a low step, it is necessary to set the threshold values T1 and T2 to be small in accordance with the low step among the steps to be detected.

  In the case of the wheelchair 100, the rear wheel 102 has a larger wheel diameter than the front wheel 101. Therefore, the rear wheel 102 passes through the steps more gently (see FIG. 11). FIG. 11 is a diagram showing a difference in the riding angle between the front wheel 101 and the rear wheel 102 when climbing a step. As shown in FIG. 11, since the rear wheel 102 has a large wheel diameter, the climb angle θ <b> 2 is smaller than the climb angle θ <b> 1 of the front wheel 101. Therefore, the pitch change when the rear wheel 102 passes through the step becomes gentler than when the front wheel 101 passes, and the peak of the pitch change becomes smaller when the rear wheel 102 passes than the front wheel 101.

  Accordingly, the difference in the absolute value of the threshold value on the front wheel 101 side and the threshold value on the rear wheel 102 side improves the step detection accuracy. An example is shown in FIG. In FIG. 12, the threshold value T1 on the front wheel 101 side> the threshold value T2 on the rear wheel 102 side. FIG. 12A shows a case of an up step. In this case, as described in FIG. 5, the threshold value T1 on the front wheel 101 side is set as a positive value, and the threshold value T2 on the rear wheel 102 side is set as a negative value. FIG. 12B shows the case of a downward step. In this case, as described in FIG. 7, the threshold value T1 on the front wheel 101 side is set as a negative value, and the threshold value T2 on the rear wheel 102 side is set as a positive value.

  In the case of the wheelchair 100, since the wheel diameter of the rear wheel 102 is larger than that of the front wheel 101, the threshold value is set so that the threshold value T1 on the front wheel 101 side> the threshold value T2 on the rear wheel 102 side. In the case of a moving body having a wheel diameter larger than that of the rear wheel 102, the threshold value may be set so that the threshold value T1 on the front wheel 101 side <the threshold value T2 on the rear wheel 102 side. Further, when the front wheels 101 and the rear wheels 102 have the same wheel diameter, the threshold value T1 and the threshold value T2 may be the same value.

  Next, setting of the threshold when there is an inclined surface before and after the step will be described. When there are inclined surfaces before and after the step, the pitch change after passing through the front wheel 101 does not return to 0, and therefore the peak value of the pitch change on the rear wheel 102 side fluctuates. Hereinafter, a description will be given with reference to FIG.

  FIG. 13A is a graph showing the relationship between the pitch change and the position when the step of 20 mm is a flat surface. FIG. 13B is a graph showing the relationship between the pitch change and the position in the case of an upward inclined surface of 4 ° after the step of 20 mm. FIG. 13C is a graph showing the relationship between the pitch change and the position in the case where the front slope of 20 mm is an upward inclined surface of 4 °. In the case of FIG. 13A, since the front and back of the step are flat, the pitch change returns to 0 after the front wheel 101 passes through the step.

  On the other hand, in the case of FIG. 13B, since the rear surface of the step is an inclined surface, the height of the rear wheel 102 does not change until the rear wheel 102 passes the step after the front wheel 101 passes the step. Only the height of 101 rises. Therefore, since the inclination of the wheelchair 100 gradually increases at a rate corresponding to the angle of the inclined surface, the pitch change after passing through the front wheel 101 proceeds with substantially the same pitch change. That is, the pitch change becomes a positive and substantially constant value (section in which the position in FIG. 13B is about 0.45 to about 0.7). Thereafter, the pitch change when the rear wheel 102 passes through the step changes from the above-described substantially positive value to the negative direction. It can be seen that the peak value in the negative direction of the pitch change is smaller than that in FIG. Therefore, since the negative peak value of the pitch change is close to the threshold value −T2, the detection range is narrowed, and detection omission may occur depending on the setting of the threshold value (X1 in FIG. 13B).

  In the case of FIG. 13C, since the front of the step is an inclined surface, the height of the front wheel 101 does not change until the rear wheel 102 passes the step after the front wheel 101 passes the step. Only the height of 102 rises. Therefore, since the inclination of the wheelchair 100 gradually decreases at a rate corresponding to the angle of the inclined surface, the pitch change after passing through the front wheel 101 proceeds with substantially the same pitch change. That is, the pitch change becomes a negative and substantially constant value (section in which the position in FIG. 13C is about 0.45 to about 0.7). Compared to FIG. 13 (a), the negative substantially constant value during this period is close to the threshold value −T2, so that a detection error is likely to occur, and depending on the setting of the threshold value, there is a possibility of being erroneously detected as passing the rear wheel 102. Yes (X2 in FIG. 13B).

  In order to avoid the above-described problem, the determination on the rear wheel 102 side is performed by comparing the pitch change amount ΔPd from the average value Pd_ave of the pitch change after passing through the front wheel 101 with a threshold value as shown in FIG. . That is, the change from the average value (average value Pd_ave) of the pitch change after the first pitch change becomes greater than or equal to the first threshold value (front wheel 101 side threshold value) to less than the first threshold value to the second pitch change. The absolute value of the amount (pitch change amount ΔPd) is compared with the second threshold value (rear wheel 102 side threshold value). The average value Pd_ave after passing through the front wheel 101 is preferably set so that the section having a small pitch change shown in FIG. 13 can be detected. For example, after the rate of change in pitch change is stabilized below a predetermined value, it may be set until the next exceeds the predetermined value.

  In addition, since this section can be considered to be substantially the same as the wheel base length H of the wheelchair 100, it is calculated during the movement of the wheel base length H after the rate of change in pitch change stabilizes below a predetermined value. It may be an average of pitch changes. Here, the wheel base length H in this embodiment is a length from the ground contact position of the front wheel 101 to the ground contact position of the rear wheel 102. When the wheel is grounded on the surface, the center of the grounding surface of the wheel may be regarded as the grounding position.

  Next, the operation of the arithmetic device 1 having the above-described configuration will be described with reference to the flowchart of FIG.

  First, in step S101, threshold values T1 and T2 are set in the level difference detection unit 13, and the process proceeds to step S102. The threshold values T1 and T2 are threshold values set to values (pitch change) corrected by dividing the pitch rate detected by the gyro sensor 4 by the traveling speed. The threshold value T1 is a threshold value for detecting that the front wheel 101 has passed through the step, and corresponds to a first threshold value. The threshold value T2 is a threshold value for detecting that the rear wheel 102 has passed through the step, and corresponds to a second threshold value. These threshold values T1 and T2 can be adjusted according to the wheelchair 100. Alternatively, a data table corresponding to the wheelchair type may be prepared in advance, and the threshold values T1 and T2 and the wheelbase length H may be automatically set by inputting the wheelchair type.

  Next, in step S102, the pitch change Pd is calculated from the pitch rate and the traveling speed, and the process proceeds to step S103. In this step, the pitch rate acquisition unit 11 acquires the pitch rate detected by the gyro sensor 4, and the correction unit 12 divides the acquired pitch rate by the traveling speed of the wheelchair 100 detected by the speed sensor 3 to change the pitch. Pd is calculated. That is, during traveling, the pitch rate is acquired and the pitch change Pd is calculated.

  Next, in step S103, the level difference detection unit 13 determines whether or not the pitch change Pd calculated in step S102 is less than -T1, and if this condition is satisfied (in the case of Yes), the process proceeds to step S104, where the condition is satisfied. If not (No), the process proceeds to step S105. That is, it is detected that the pitch change Pd is negative and the absolute value is equal to or greater than the first threshold value (T1). That is, the pitch rate that is the basis of the pitch change Pd determined to be equal to or greater than the threshold T1 in this step is the first pitch rate. Further, the pitch change Pd calculated by the correction unit 12 becomes the first pitch change.

  Next, in step S104, since it is determined that the condition is satisfied in step S103, the level difference detection unit 13 temporarily determines that the currently passing level difference is a downward level difference, and sets -1 in the level difference candidate flag. The process proceeds to S107. In this step, since the determination on the rear wheel 102 side has not been performed yet, a provisional determination is performed, and a step candidate flag set in the arithmetic unit 1 is set as a flag indicating the determination. Note that the value set in the step candidate flag is not limited to −1, and may be a value indicating that it has been provisionally determined to descend.

  On the other hand, in step S105, the level difference detection unit 13 determines whether or not the pitch change Pd calculated in step S102 is equal to or greater than T1, and if this condition is satisfied (in the case of Yes), the process proceeds to step S106, and the condition is not satisfied. In the case (in the case of No), it is determined that the step is not detected, and this flowchart is ended. That is, it is detected that the first pitch change (pitch change Pd) is positive and the absolute value is equal to or greater than the first threshold value (T1).

  Next, in step S106, since it is determined that the condition is satisfied in step S105, the step detection unit 13 makes a provisional determination that the step currently being passed is an ascending step, sets 1 to the step candidate flag, and sets step S107. Proceed to In this step, since the determination on the rear wheel 102 side has not been performed yet, a temporary determination is performed, and the step candidate flag is set in the same manner as in step S104. Note that the value set in the step candidate flag is not limited to 1, but may be a value indicating that it is temporarily determined to be up.

  Next, in step S107, after the front wheel 101 exceeds the step, an average pitch change Pd_ave during the movement of the wheel base length H is calculated, and the process proceeds to step S108. In this step, the level difference detection unit 13 calculates the average pitch change Pd_ave in the section from the front wheel 101 passing through the level difference to the rear wheel level as described in FIG. Further, the moving distance of the wheel base length H may be calculated from the latitude and longitude detected by the GPS receiver 2 based on the preset wheel base length H, or the wheel of the wheelchair 100 (rear wheel 102). The rotation angle may be multiplied by a preset wheel circumference. The rotation angle of the wheel of the wheelchair 100 can be detected by providing an angle sensor or the like on the wheel.

  Next, in step S108, the correction unit 12 detects the pitch change Pd after moving the wheel base length H, and subtracts the average pitch change Pd_ave calculated in step S107 from the pitch change to calculate the pitch change amount ΔPd. Then, the process proceeds to step S109. In this step, the step detection unit 13 calculates the pitch change amount ΔPd from the average value Pd_ave after passing through the front wheel 101 as described in FIG.

  Next, in step S109, the level difference detection unit 13 determines whether the pitch change amount ΔPd is equal to or greater than T2 as a result of the comparison in step S109. If this condition is satisfied (in the case of Yes), the process proceeds to step S110. If not satisfied (in the case of No), the process proceeds to step S112. In this step, the pitch change amount ΔPd calculated in step S108 is compared with the threshold value T2. That is, it is detected that the pitch change (pitch change amount ΔPd) is positive and the absolute value is equal to or greater than the second threshold value (T2). That is, the distance between the ground contact position of the front wheel 101 and the ground contact position of the rear wheel 102 from the position at which the first pitch rate that is the basis of the pitch change amount determined to be equal to or greater than the second threshold T2 in this step is acquired. The pitch rate acquired when the wheelchair 100 moves a distance related to the distance becomes the second pitch rate. The pitch change amount ΔPd calculated by the correction unit 12 is the second pitch change.

  Next, in step S110, the level difference detection unit 13 determines whether or not the level difference candidate flag is -1, and if it is -1 (in the case of Yes), the process proceeds to step S111, otherwise (in the case of No). ) Determines that the step is not detected, and the present flowchart is terminated.

  Next, since the step candidate flag indicates a down step in step S111, the step detection unit 13 formally determines that the step that has passed is a down step, and proceeds to step S115. That is, the step is detected based on the first pitch change (pitch change Pd) and the second pitch change (pitch change amount ΔPd).

  On the other hand, in step S112, the level difference detection unit 13 determines whether or not the pitch change amount ΔPd is less than −T2, and if this condition is satisfied (in the case of Yes), the process proceeds to step S113, and if the condition is not satisfied (No In the case of (), it is determined that the step is not detected, and this flowchart is ended. That is, it is detected that the second pitch change (pitch change amount ΔPd) is negative and the absolute value is equal to or greater than the second threshold value (T2).

  Next, in step S113, the level difference detection unit 13 determines whether or not the level difference candidate flag is 1. If it is 1 (in the case of Yes), the process proceeds to step S114, and if not (in the case of No). It is determined that the step is not detected, and this flowchart is ended.

  Next, since the step candidate flag indicates an up step in step S114, the step detection unit 13 formally determines that the step that has passed is an up step, and proceeds to step S115. That is, the step is detected based on the first pitch change (pitch change Pd) and the second pitch change (pitch change amount ΔPd).

  Next, in step S115, the level difference detection unit 13 acquires the position (latitude, longitude) from the GPS receiver 2, and records the position of the level difference in an internal memory or the like. In addition, when the distance of wheelbase length is detected using the GPS receiver 2 by step S107, you may record the position acquired at that time. That is, the level difference detection unit 13 functions as a position acquisition unit that acquires information regarding the position where the level difference is detected. The information recorded in this step is transmitted to the server device 50 via the communication device 5 and the network N. The transmission timing to the server device 50 may be at the time of detecting a step, or may be set arbitrarily such as at a fixed time interval or at the end of traveling.

  As is clear from the above description, steps S102 and S108 are the acquisition process and the correction process, and steps S103 to S107 and steps S109 to S114 are the step detection process.

Next, a method for estimating the height of the step will be described with reference to FIGS. When passing through a step with no inclination as shown in FIG. 16, only the front wheel 101 of the wheelchair 100 exceeds the step and the period until the rear wheel 102 starts to exceed the step proceeds with substantially the same pitch angle. Therefore, the height of the step can be obtained by obtaining the pitch angle when passing through the step. Here, as shown in FIG. 16, when the pitch angle is Pa, the wheel base length is H, and the step height is h, the following equation (1) is approximately established.
sinPa = h / H (1)

Therefore, the step height h can be obtained by the following equation (2). In equation (2), when Pa is negative, h can be negative, so that it is possible to discriminate between upstream and downstream.
h = HsinPa (2)

  Here, a change in pitch angle when there are inclined surfaces before and after the step will be described with reference to FIG. FIG. 17 shows an example of the case where there is an inclination and a step and a graph of the change in the pitch angle, and an example of only the inclination (no step) and a graph of the change in the pitch angle. Also, in FIG. 17, as an example of inclination, (a) flat surface to ascending inclined surface, (b) ascending inclined surface to a flat surface, (c) flat surface to descending inclined surface, and (d) a descending inclined surface to flat surface. Four types of examples are shown.

  As shown in FIG. 17, when the vehicle passes through a step with a slope, the pitch angle changes from when the front wheel 101 passes through the step until the rear wheel 102 passes through the step. The gradient of change is equal to the gradient when there is no step.

  Therefore, as shown in FIG. 18, by subtracting the pitch angle in the case of only tilt (no step) from the pitch angle in the case of passing through a step with a slope, the pitch angle of only the step is obtained. FIG. 18 is an example in which the pitch angle in the case of only the inclination (no step) is subtracted from the pitch angle in the case of passing through a step with an inclination in the examples of FIGS.

  Next, a specific step height estimation method based on the above-described method will be described with reference to FIGS. FIG. 19A is a graph showing an example of a change in pitch rate detected by the gyro sensor 4, FIG. 19B is a graph after correcting the change in pitch rate and converting it into a pitch change, and FIG. 19C. These are graphs showing changes in pitch angle. In the present embodiment, the data calculation before the step is executed after the step is detected based on the pitch rate and the pitch change shown in FIGS. 19A and 19B, and the gyro sensor is placed before and after the step. The height is estimated on the basis of the pitch angle data acquired from 4.

  Next, a step height estimation method that operates in the arithmetic device 1 will be described with reference to the flowchart of FIG. In the example of FIG. 20, the level difference detection unit 13 is described as including a holding unit such as a memory, holding pitch angle data for a predetermined period, and estimating the height of the level difference after passing through the level difference. The height of the step may be detected in real time.

  First, in step S201, a step detection process is performed. The step detection process may be performed by the method described above, for example, but may be another method.

  Next, in step S202, the level difference detection unit 13 determines whether or not a level difference is detected as a result of the process in step S201. If a level difference is detected (in the case of Yes), the process proceeds to step S203. If not detected (No), the process is terminated.

  Next, in step S203, the level difference detection unit 13 calculates the pitch angle Pa by integrating the pitch change. Since the pitch rate during traveling is obtained from the gyro sensor 4 and the pitch change is also calculated, the pitch angle Pa is calculated by integrating the pitch change calculated in the above-described step detection process with a unit distance. That is, the level difference detection unit 13 functions as a pitch angle acquisition unit. Instead of calculating the pitch angle Pa from the pitch change, an angle sensor or the like that directly detects the pitch angle may be provided. In this case, this step is a process for acquiring the pitch angle from the sensor. Alternatively, the pitch angle may be calculated by time integration of the pitch rate.

  Next, in step S204, the level difference detection unit 13 performs an averaging process on the data of the pitch angle Pa of 0.15 m to 0.1 m before the level difference, calculates the pitch angle Pa_before before the level difference, and proceeds to step S205 (step S205). FIG. 19A). That is, the average value of the pitch angles acquired while traveling the first distance (0.15 m to 0.1 m before the step) immediately before the front wheel 101 reaches the step is defined as the first pitch angle. The position and range (0.15 m to 0.1 m) for obtaining the pitch angle for calculating the pre-step pitch angle Pa_before may be changed as appropriate.

  Whether the front wheel 101 or the rear wheel 102 has reached the step can be detected by a change in the pitch rate, as shown in FIGS. For example, when a threshold value is set for the pitch rate and the absolute value of the pitch rate is equal to or greater than the threshold value, it is determined that the front wheel 101 or the rear wheel 102 has reached a step, and when the threshold value is less than the threshold value after the determination, What is necessary is just to determine with the front wheel 101 or the rear wheel 102 having passed the level | step difference.

  Next, in step S205, the level difference detection unit 13 performs an averaging process on the pitch angle data of 0.1 m to 0.15 m after the level difference to calculate the pitch angle Pa_after after the level difference, and proceeds to step S206 (FIG. 19 B). That is, the average value of the pitch angles acquired while traveling the second distance (0.1 m to 0.15 m after the step) immediately after the rear wheel 102 passes through the step is defined as the second pitch angle. The position and range (0.1 m to 0.15 m) for acquiring the pitch angle for calculating the post-step pitch angle Pa_after may be appropriately changed. Therefore, in the case of the example of this flowchart, it is only necessary that the pitch angle data for 0.3 m + wheel base length, which is at least from 0.15 m before the step to 0.15 m after the step, be held in the memory or the like.

  Next, in step S206, the level difference detection unit 13 calculates an average value Pa_slope of the pitch angle Pa_before before the level difference and the pitch angle Pa_after after the level difference, and then proceeds to step S207.

  Next, in step S207, the level difference detection unit 13 determines a portion where the pitch changes little between the start point and the end point of the level difference, that is, the pitch immediately before the rear wheel 102 climbs the level difference after the front wheel 101 climbs the level difference. The corner data is averaged to calculate the pitch angle Pa_step_slope including the step and the slope, and the process proceeds to step S208 (C in FIG. 19). That is, the pitch angle Pa_step of only this step becomes the third pitch angle acquired from when the front wheel 101 passes the step until the rear wheel 102 reaches the step. In this flowchart, the front wheel 101 passes the step. The average value of the pitch angles acquired while traveling at least partly from when the rear wheel 102 reaches the level difference.

  Next, in step S208, the average value Pa_slope is subtracted from the pitch angle Pa_step_slope including the step and the inclination, and the pitch angle Pa_step is calculated only for the step, and the process proceeds to step S209.

  Next, in step S209, the step height h is calculated by substituting the pitch angle Pa_step for only the step into Pa in the equation (2). That is, the height of the step is determined based on the first pitch angle, the second pitch angle, the third pitch angle, and the length between the ground contact position of the front wheel and the ground contact position of the rear wheel (wheel base length H). Is estimated (calculated).

  As is clear from the above description, step S203 is an acquisition process, and steps S204 to S209 are estimation processes.

  In the flowchart shown in FIG. 20, the pitch angle Pa_before before the step, the pitch angle Pa_after after the step, and the pitch angle Pa_step_slope including the step and the slope are obtained by the averaging process. A pitch angle may be adopted as each pitch angle. 20 is executed by the arithmetic device 1, the pitch change data may be transmitted to the server device 50 and executed by the arithmetic device 52 of the server device 50.

  Next, a method of reflecting the step height h calculated in the flowchart of FIG. 20 in the barrier-free map (statistic processing method) will be described with reference to the flowchart of FIG. The flowchart shown in FIG. 21 is executed by the arithmetic device 52 of the server device 50.

  First, in step S301, the computing device 52 receives the ID of the wheelchair 100, the step position Sp, and the step height h received by the communication device 51, and proceeds to step S302. The ID of the wheelchair 100 is an ID given in advance for each wheelchair and is set in the computing device 1. Further, the step position Sp is the position of the step recorded in step S115 in FIG. 15, and the step height h is the value calculated in step S209 in FIG. These values are transmitted from the computing device 1 to the server device 50 via the communication device 5.

  Next, in step S302, the weighting value W of the wheelchair 100 is acquired from the ID of the wheelchair 100 received in step S301. Then, the arithmetic unit 52 performs an averaging process on the step height h at the step position Sp received by the communication device 51 with the past data using W (after considering), and proceeds to step S303. A value calculated by the averaging process is set as an average height h_ave, and is stored in the storage device 43 as average height information 531. This average height h_ave is an average value after weighting processing described later with respect to the step height h detected by the plurality of wheelchairs 100.

  This weight value W indicates the reliability of the step height h transmitted in the past, and is stored in the storage device 53 in association with the ID of the wheelchair 100. The weighting value W may be increased as the reliability increases, for example, with an initial value of 1. Then, the weighted average is calculated together with the data of the average height information 531 of the storage device 53 in which past data is stored.

  Next, in step S303, the arithmetic unit 52 changes the weighting value W for the wheelchair 100 of the ID received in step S301, and proceeds to step S304. In this step, when the difference in the step height h received by the communication device 51 with respect to the average height h_ave is large, the weight value W of the wheelchair 100 is lowered by a predetermined amount. When the difference in the step height h received by the communication device 51 with respect to the average height h_ave is small, the weighting value W of the wheelchair 100 is increased by a predetermined amount. That is, the wheelchair that outputs the step height h close to the average height h_ave increases the weighting value W.

  Next, in step S304, a barrier free map is created or updated based on the average height h_ave calculated in step S302. In this step, for example, the level determination unit 521 of the arithmetic device 52 compares the step level threshold with the average height h_ave calculated in step S302 to determine the step level. This threshold is set in advance in accordance with the step level, for example, 5 cm, 10 cm, etc. For example, when the calculated average height h_ave is 6.8 cm, it is in the range of 5 cm to less than 10 cm. Judged as step level 2 or the like.

  Then, the update unit 522 of the arithmetic device 52 creates or updates the barrier information stored in the map information 532 of the storage device 53 (creates or updates the barrier-free map) based on the determined level difference result.

  According to the present embodiment, the rear wheel 102 of the wheelchair 100 indicates the first pitch rate when the front wheel 101 of the wheelchair 100 passes on the traveling surface by the pitch rate acquisition unit 11 and the position where the first pitch rate is acquired. The second pitch rate at the time of passing is acquired, and the correction unit 12 corrects the acquired first pitch rate and second pitch rate by dividing by the traveling speed of the wheelchair 100. And the level | step difference detection part 13 detects a level | step difference based on the 1st pitch change and 2nd pitch change which are the results which the correction | amendment part 12 correct | amended. By doing so, the pitch rate when the two wheels of the front wheel 101 and the rear wheel 102 pass through the step is corrected by the speed, so that the step can be detected without depending on the speed. Therefore, the step on the road surface can be detected with high accuracy even if the step is relatively low.

  Further, the level difference detection unit 13 sets a distance (for example, wheelbase length H) related to the length between the ground contact position of the front wheel 101 and the ground contact position of the rear wheel 102 from the position at which the first pitch rate is acquired to the wheelchair 100. It is good also considering the pitch rate acquired when this moved as the 2nd pitch rate. By doing in this way, the position which detects a 2nd pitch rate can be specified based on the length of the grounding position of front wheel 101 of wheelchair 100 and the grounding position of rear wheel 102 which are known values.

  In addition, the step detection unit 13 detects the position as a step when the absolute value of the first pitch change is equal to or greater than the predetermined threshold T1 and the absolute value of the second pitch change is equal to or greater than the predetermined threshold T2. May be. In this way, the pitch can be detected when the pitch rate having a certain absolute value or more is detected when the front wheel 101 passes and when the rear wheel 102 passes, so that the step can be detected with high accuracy. it can.

  Further, the front wheel 101 and the rear wheel 102 may have different wheel diameters, and the threshold value T1 and the threshold value T2 are set to be smaller as the wheel diameter is larger. Even when the wheel diameter is smaller than 102, the level difference can be detected with high accuracy.

  Further, the level difference detection unit 13 may compare the pitch change amount ΔPd, which is a change amount from the average value Pd_ave of the pitch change after the first pitch change is less than the threshold value T1, with the threshold value T2. By doing so, for example, when there is an inclination before and after the step, erroneous detection of the second pitch change can be prevented.

  Also, the step detection unit 13 calculates the pitch angle Pa_before before the step calculated just before the front wheel 101 reaches the step, the pitch angle Pa_after after the step calculated immediately after the rear wheel 102 passes the step, and the front wheel 101 passes the step. The height of the step is estimated on the basis of the pitch angle Pa_step_slope including the step and the inclination calculated after the rear wheel 102 reaches the step and the wheelbase length H of the wheelchair 100. . In this way, not only the pitch angle when only the front wheel 101 passes through the step, but also the pre-step pitch angle Pa_before immediately before the step and the post-step pitch angle Pa_after after the step are acquired, so Even if there are front and back inclined surfaces, the step height can be accurately estimated.

  Further, an average value of pitch angles calculated while traveling from 0.15 m to 0.1 m immediately before the front wheel 101 reaches the step is defined as a pitch angle Pa_before before the step. By doing in this way, pitch angle Pa_before before level | step difference can be made hard to be influenced by noise components, such as a small unevenness | corrugation on a driving | running | working surface, and a precision can be improved.

  In addition, an average value of pitch angles acquired while the rear wheel 102 travels 0.1 m to 0.15 m immediately after passing through the step is defined as a post-step pitch angle Pa_after. By doing so, the post-step pitch angle Pa_after can be made less susceptible to noise components such as small irregularities on the running surface, and the accuracy can be improved.

  In addition, an average value of pitch angles acquired while traveling at least part of the time from when the front wheel 101 passes the step until the rear wheel 102 reaches the step is defined as a pitch angle Pa_step_slope including the step and the slope. Yes. By doing so, the pitch angle Pa_step_slope including the step and the inclination can be made less susceptible to noise components such as small irregularities on the running surface, and the accuracy can be improved.

  Further, the pitch rate of the wheelchair 100 is further acquired, and the level difference detection unit 13 determines that the front wheel 101 or the rear wheel 102 has reached the level difference when the absolute value of the acquired pitch rate is equal to or greater than a predetermined threshold value. Then, when it becomes less than the threshold value thereafter, it may be determined that the front wheel 101 or the rear wheel 102 has passed the step. In this way, when the wheels such as the front wheel 101 and the rear wheel 102 reach the step, the pitch of the vehicle body changes greatly, so that the pitch rate changes. Therefore, it is possible to detect that the wheel has exceeded the step due to the change in the pitch rate.

  Further, when a step is detected, the height of the step may be estimated based on a pitch angle held in a memory or the like. By doing so, it is possible to maintain the pitch angle before and after the step detection and to estimate the height of the step after the step detection. For example, the height of the step may be estimated by the server device 50 without being calculated by the arithmetic device 1.

  In addition, since the server device 50 sets the average value of the step heights h detected by the plurality of wheelchairs 100 as the step height at the position, the detection accuracy of the step height can be improved.

  Further, since the server device 50 performs weighting for each wheelchair 100 using the weighting value W, the step height can be reflected based on the reliability of the value detected by the wheelchair 100. Detection accuracy can be improved.

  In the embodiment described above, the step level is determined by the server device 50, but the determination may be performed based on the step height h calculated by the arithmetic device 1 mounted on the wheelchair 100. Then, the determination result, the latitude and longitude of the position where the step is detected, and the ID of the wheelchair 100 may be transmitted to the server device 50 via the communication device 5.

  In the above-described embodiment, the calculation device 1 mounted on the wheelchair 100 is described as the step detection device. However, the calculation device 1 may not be a dedicated device. For example, a GPS receiver, a gyro sensor, and a speed sensor are mounted. If the terminal device has a communication function such as a smartphone (or can be connected), the above-described flowchart can be used as an application (computer program) to function as a step detection device. In this case, a holder or the like may be provided on the wheelchair, and a smartphone or the like may be attached to the holder. That is, it becomes a level | step difference detection apparatus which can be attached to a moving body.

  Further, in the above-described embodiment, since it is possible to obtain information on whether or not the vehicle has passed an ascending step or a descending step, what kind of step is determined by the information and the direction of movement such as the movement locus of the wheelchair 100 (which It may be determined whether or not an up or down step occurs when moving from the direction.

  In the above-described embodiments, the wheelchair is described as the moving body. However, senior cars, strollers, golf carts, bicycles, automobiles, carts, robots having wheels, and the like are provided with front and rear wheels for traveling on the traveling road surface. I just need it.

  Further, the present invention is not limited to the above embodiment. That is, those skilled in the art can implement various modifications in accordance with conventionally known knowledge without departing from the scope of the present invention. Of course, such modifications are included in the scope of the present invention as long as the configuration of the step detecting device of the present invention is provided.

DESCRIPTION OF SYMBOLS 1 Arithmetic unit 2 GPS receiver 3 Speed sensor 4 Gyro sensor 5 Communication device (transmission means)
DESCRIPTION OF SYMBOLS 10 Level | step difference detection apparatus 11 Pitch rate acquisition part (acquisition means)
12 Correction part (correction means)
13 Step detection unit (step detection means, position acquisition means, estimation means)
50 Server device 100 Wheelchair (moving body)
101 Front wheel 102 Rear wheel

Claims (8)

An acquisition means for acquiring a pitch change which is a change in pitch angle per unit moving distance of the moving body;
I) acquired by the acquisition means, i) a first pitch change when the front wheel of the moving body passes on the running surface, and ii) a rear wheel of the moving body passes the position where the first pitch change is acquired. A step detecting means for detecting a step based on the second pitch change when
A level difference detection apparatus comprising:   The said acquisition means acquires the said pitch change by correct | amending the pitch rate which is the change per unit time of the pitch angle of the said mobile body based on the travel speed of the said mobile body. The level | step difference detection apparatus of description.   The step detecting means determines the position when the absolute value of the first pitch change is equal to or greater than a predetermined first threshold value and the absolute value of the second pitch change is equal to or greater than a predetermined second threshold value. The level difference detection apparatus according to claim 1, wherein the level difference detection apparatus detects the level difference.   The level difference detecting means is the amount of change from the average value of the pitch change to the second pitch change after the absolute value of the first pitch change is greater than or equal to a predetermined first threshold value and less than the first threshold value. The step difference detection device according to claim 1, wherein an absolute value of the step is compared with a predetermined second threshold value.   The step detection device according to claim 3 or 4, wherein the front wheel and the rear wheel have different wheel diameters, and the first threshold value and the second threshold value are smaller as the wheel diameter is larger. A step detection method for a step detection device for detecting a step on a running surface,
An acquisition step of acquiring a pitch change that is a change in pitch angle per unit moving distance of the moving body;
I) acquired in the acquisition step, i) a first pitch change when the front wheel of the moving body passes on the traveling surface, and ii) a rear wheel of the moving body passes through the position where the first pitch change is acquired. A step detecting step for detecting a step based on the second pitch change when
A step detection method comprising:   A step detection program that causes the computer to execute the step detection method according to claim 6.   A computer-readable recording medium storing the step detection program according to claim 7.

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