JP2017072926A - Level difference detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a level difference detection device capable of accurately detecting a level difference on a road.SOLUTION: A level difference detection device 10 mounted on a wheel-chair having a front wheel and a rear wheel, comprises a level difference detection part 13 which acquires a pitch rate detected by a gyro-sensor 4 for detecting the pitch rate of the wheel-chair and detects a level difference on a road on which the wheel-chair travels and passes based on the acquired pitch rate. The level difference detection part 13 detects the level difference based on a first pitch rate which is the pitch rate detected by the gyro-sensor 4 when the front wheel passes on the road and a second pitch rate which is the pitch rate detected by the gyro-sensor 4 when the rear wheel passes the position at which the first pitch rate is detected.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a step detection device that detects a step on a road surface.

  A barrier-free map has been created that shows the level of the road surface and the like, and displays easily accessible routes for wheelchair users and the like. 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, changes in road surface conditions such as road construction may not be reflected in the barrier-free map, and may be far from the actual road surface conditions.

  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 road surface is detected by a vibration detection means, the specific 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 road surface with high accuracy, for example.

  In order to solve the above-mentioned problem, the invention according to claim 1 is a step detecting device that is mounted on or attachable to a moving body including a front wheel and a rear wheel. A step detection unit that acquires a pitch rate detected by a pitch rate detection unit that detects a pitch rate, and detects a step on a road surface on which the moving body travels and passes based on the acquired pitch rate, The step detecting means includes a first pitch rate which is a pitch rate detected by the pitch rate detecting means when the front wheel passes on the road surface, and the rear wheel passes a position where the first pitch rate is detected. The step detection device detects the step based on a second pitch rate which is a pitch rate detected by the pitch rate detection means.

  The invention according to claim 12 is a step detection method that is executed by a step detection device that is mounted on or attachable to a moving body including a front wheel and a rear wheel. Including a step detection step of acquiring a pitch rate detected by a pitch rate detection means for detecting a pitch rate, and detecting a step on the road surface on which the moving body travels and passes based on the acquired pitch rate, The step detecting step includes a first pitch rate that is detected by the pitch rate detecting means when the front wheel passes on the road surface, and the rear wheel that has passed the position where the first pitch rate is detected. In this case, the step is detected based on the second pitch rate which is the pitch rate detected by the pitch rate detecting means.

  A thirteenth aspect of the invention is a step detection program that causes a computer to execute the step detection method of the twelfth aspect.

  The invention described in claim 14 is a computer-readable recording medium in which the step detection program according to claim 13 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 1 grade | etc., 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. 5 is a graph showing changes in pitch rate, pitch angle, and vertical acceleration in the state of FIG. 4. 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, a pitch angle, and a vertical acceleration. It is explanatory drawing which showed the relationship of the height of a level | step difference with wheelbase length. It is a graph of the peak value of the pitch rate before and after normalization with the wheelbase length. 10 is a table summarizing average values, standard deviations, and coefficient of variation calculated from the graph shown in FIG. 9. 3 is a flowchart showing the operation of the arithmetic device shown in FIG. It is the flowchart which showed operation | movement of the server apparatus shown by FIG.

  Hereinafter, the level | step difference detection apparatus concerning one Embodiment of this invention is demonstrated. A level difference detection device according to an embodiment of the present invention is mounted on or attachable to a moving body including a front wheel and a rear wheel. Then, the step detection means has a first pitch rate that is the pitch rate detected by the pitch rate detection means when the front wheel passes on the road surface, and a pitch when the rear wheel passes the position where the first pitch rate is detected. The step is detected based on the second pitch rate which is the pitch rate detected by the rate detecting means. By doing so, the step can be detected by the change in the pitch rate of the two wheels, the front wheel and the rear wheel, so that the step on the road surface can be detected with high accuracy even at a relatively low step. .

  Further, the step detecting means may use the pitch rate detected when the moving body moves a distance related to the wheel base length of the moving body from the position on the road surface where the first pitch rate is detected as the second pitch rate. Good. By doing in this way, the position which detects a 2nd pitch rate can be specified based on the wheel base length which is the length between the front wheel of a mobile body, and a rear wheel and is a known value.

  Further, the step detecting means detects the position of the first pitch rate when the absolute value of the first pitch rate is equal to or greater than a predetermined first threshold and the absolute value of the second pitch rate is equal to or greater than a predetermined second threshold. You may detect as. 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.

  The apparatus further includes an acceleration acquisition unit that acquires an acceleration detected by an acceleration detection unit that detects an acceleration in a direction perpendicular to the moving plane of the moving body, and the step detection unit acquires the acceleration when the first pitch rate is detected. The step may be detected based on the acceleration acquired by the means and the acceleration acquired by the acceleration acquisition means when the second pitch rate is detected. In this way, since the acceleration in the vertical direction can be taken into consideration in addition to the pitch rate, the step detection accuracy can be further improved.

  Further, the step detecting means detects the second pitch rate when the absolute value of the acceleration acquired by the acceleration acquiring means is greater than or equal to a predetermined third threshold when detecting the first pitch rate. When the acquired absolute value of acceleration is equal to or greater than a predetermined fourth threshold value, the position may be detected as a step. By doing so, the first pitch rate can be set when the vertical acceleration of a certain level or more is detected when the front wheel passes and when the rear wheel passes, and the step can be detected with high accuracy.

  Further, the step detecting means may detect the step based on the sign of the pitch rate acquired from the pitch rate detecting means and the direction of change of acceleration acquired by the acceleration acquiring means. By doing so, it is possible to consider the sign of the pitch rate, that is, whether the pitch rate is positive or negative, and the direction of change in acceleration, that is, whether the acceleration has increased or decreased. It is possible to detect the step with high accuracy in consideration of the direction of acceleration and the direction of acceleration.

  Further, the step detecting means may detect whether the step through which the mobile body has passed is an up step or a down step based on the first pitch rate code and the second pitch rate code. In this way, it is possible to determine whether the step that has passed through the sign of the two pitch rates is an up step or a down step.

  The step detecting means detects the first normalized pitch rate obtained by normalizing the peak value of the first pitch rate with the wheel base length and / or the peak value of the second pitch rate when the step is detected. Normalized pitch rate information including the second normalized pitch rate normalized by (1) is generated. Then, the step acquired from the position acquisition unit is detected as information for the position acquisition unit to acquire information about the position where the step is detected, and the transmission unit to determine the level of the step on the road surface by the external server device. The information regarding the position and the normalized pitch rate information may be transmitted to the server device. By doing in this way, the detection error by the difference in wheelbase length can be reduced by normalized pitch rate information. Further, the server device can accumulate the result of determining the level difference based on the information collected from the plurality of level difference detection devices. Therefore, the determination accuracy of the step can be increased.

  The step detecting means detects the first normalized pitch rate obtained by normalizing the peak value of the first pitch rate with the wheel base length and / or the peak value of the second pitch rate when the step is detected. The level of the step may be determined based on the second normalized pitch rate normalized in step (b). By doing in this way, the detection error by the difference in wheelbase length can be reduced.

  In addition, the position acquisition unit acquires information about the position where the step is detected, and the transmission unit transmits the step level determined by the step detection unit and the information about the position where the step is detected to an external server device. It may be. By doing in this way, the result of having determined the level difference based on the information collected from the plurality of level difference detection devices can be accumulated in the server device.

  The step detection method according to an embodiment of the present invention includes a first pitch rate that is a pitch rate detected by the pitch rate detection means when the front wheel passes on the road surface in the step detection step, and a first pitch rate. The step is detected based on the second pitch rate, which is the pitch rate detected by the pitch rate detecting means when the rear wheel has passed the position where is detected. By doing so, the step can be detected by the change in the pitch rate of the two wheels, the front wheel and the rear wheel, so that the step on the road surface can be detected with high accuracy even at a relatively low step. .

  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, a step can be detected by using a computer based on a change in the pitch rate of the two wheels, the front wheel and the rear wheel, so that the step on the road surface can be detected with high accuracy.

  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 detecting 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, an acceleration sensor 3 as an acceleration 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. Here, the arithmetic device 1 and the communication device 5 constitute a step detecting device 10 according to an embodiment of the present invention.

  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 to thereby execute a pitch rate acquisition unit 11, an acceleration acquisition unit 12 as an acceleration acquisition unit, 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 acceleration acquisition unit 12 acquires the acceleration detected by the acceleration sensor 3 and the like.

  The level difference detection unit 13 detects a level difference on the road surface based on the pitch rate (first pitch rate and second pitch rate) acquired by the pitch rate acquisition unit 11. The step detection method will be described later. That is, the level difference detection unit 13 functions as a level difference detection unit that detects a level difference on the road surface on which the mobile body (wheelchair 100) travels and passes based on the acquired pitch rate. 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 road surface, Comprising: One road surface and the next road surface are the vertical surfaces or more than predetermined height or A position connected by 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 acceleration sensor 3 detects acceleration (vertical acceleration) in a direction perpendicular to a moving plane in which the wheelchair 100 travels and moves. The acceleration sensor 3 may be any type of sensor such as a capacitance type or a piezoresistive type, but is preferably small because it is mounted on the wheelchair 100.

  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 based on the information transmitted from the arithmetic device 1. The level of the step is obtained by dividing the height of the step by level. For example, the level of 0 or more and less than 5 cm is determined based on a predetermined threshold such as level 1 or level 2 or more 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 information such as a normalized pitch rate transmitted from the computing device 1 as normalized pitch rate 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 showing a state of movement of the wheelchair 100 when passing through the ascending step U, and FIG. 5 is a graph showing changes in pitch rate, pitch angle, and vertical acceleration in the state of FIG. Note that the vertical acceleration graph in FIG. 5C has an initial value of about 9.8 m / s ² and is a state in which gravitational acceleration is detected as the initial value. That is, FIG. 5C means that downward acceleration is detected in advance, and downward acceleration increases as the value increases.

  First, the state of FIG. 4A is a state before passing through the upstep U. In this case, no significant changes occur in the pitch rate, pitch angle, and vertical acceleration (a in FIG. 5A). Next, the state shown in FIG. 4B is a state in which the front wheel 101 climbs the ascending step U (the front wheel 101 collides with the step). 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). Further, an upward force is received from the upward step U and an upward movement occurs, so that an upward vertical acceleration is generated and the vertical acceleration increases (b in FIG. 5C).

  Next, the state shown in FIG. 4C is a state in which the rear wheel 102 climbs the ascending step U (the rear wheel 102 collides with the step). 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). Further, since the rear wheel 102 climbs the step, the vehicle body receives an upward force from the ascending step U, so that the vertical acceleration increases (c in FIG. 5C). 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, the pitch angle, and the vertical acceleration do not change significantly as before passing through the ascending step U (d in FIG. 5A).

  That is, in the case of the ascending step U, when the front wheel 101 passes the ascending step U, the pitch rate increases in the + direction and the vertical acceleration increases. That is, the vertical acceleration obtained by subtracting the pitch rate and gravitational acceleration is a positive number. When the rear wheel 102 passes through the ascending step U, the pitch rate increases in the negative direction and the vertical acceleration increases. That is, the pitch rate is a negative number, and the vertical acceleration obtained by subtracting the gravitational acceleration is a positive 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. Further, if the acceleration due to gravity is reduced, the vertical acceleration becomes a positive number in the upward direction and becomes a negative number in the downward direction. Here, when the front wheel 101 and the rear wheel 101 pass through the ascending step U, the vertical acceleration increases and then starts to decrease, but this rises to a position higher than the upper surface of the step when the wheel collides with the step, and then This is because it falls from the position to the upper surface of the step (immediately after the points b and c in FIG. 5C).

  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, pitch angle, and vertical acceleration in the state of FIG.

  First, the state of FIG. 6A is a state before passing through the descending step D. In this case, no significant changes occur in the pitch rate, pitch angle, and vertical acceleration (a in FIG. 7A). Next, the state of FIG. 6B is a state in which the front wheel 101 moves down (falls) down the 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). Further, since the front wheel 101 falls, the vertical acceleration decreases (b in FIG. 7C).

  Next, the state of FIG. 6C is a state in which the rear wheel 102 descends (falls) down 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). Further, since the rear wheel 102 falls, the vertical acceleration decreases (c in FIG. 7C). The state shown in FIG. 6D is a state after passing through the descending step D. In this case as well, the pitch rate, the pitch angle, and the vertical acceleration 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 and the vertical acceleration decreases. That is, the vertical acceleration obtained by subtracting the pitch rate and gravitational acceleration is a negative number. When the rear wheel 102 passes the descending step D, the pitch rate increases in the + direction and the vertical acceleration decreases. That is, the pitch rate is a positive number, and the vertical acceleration obtained by subtracting the gravitational acceleration is a negative number. Here, when the front wheel 101 and the rear wheel 101 pass through the descending step D, the vertical acceleration decreases and then starts to increase. This is because a bounce occurs after the wheel collides with the ground (FIG. 7 (c). ) Immediately after points b and c).

  Therefore, according to FIGS. 4 to 7, the ascending step U is determined based on the pitch rate value and sign detected by the gyro sensor 4, the absolute value of the vertical acceleration detected by the acceleration sensor 3, and the direction of change such as increase or decrease. It is possible to detect whether the vehicle has passed or passed through the descending step D. Further, by providing a threshold value for the detected pitch rate and vertical acceleration, 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.

  Next, a method for accurately discriminating the height level of the step detected by the above-described principle will be described. As described above, the presence / absence of a step can be detected by a pitch rate or the like, but the height of the step cannot be determined merely by the peak value of the pitch rate. This is because the wheelchair 100 has a different wheelbase length (the length between the axle of the front wheel 101 and the axle of the rear wheel 102).

  Here, as shown in FIG. 8, when the height of the step is h, the wheel base length is H, and the pitch angle is θ, h = Hsin θ. When the pitch angle θ is small, since sin θ≈θ, h = Hθ. Therefore, when h is unchanged, the pitch angle θ increases as the wheel base length H decreases. This is the same for the pitch rate, which is the time change of the pitch angle, and it can be said that there is a correlation (inverse proportion) between the wheel base H and the peak value of the pitch rate.

  Therefore, in this embodiment, the influence of the wheel base length is eliminated by normalizing the detected peak value of the pitch rate with the wheel base length. One example of normalization is to multiply the peak value of the pitch rate by the reciprocal of the wheelbase length. The normalization method may be another method.

  FIG. 9 shows a comparison of pitch rates before and after normalization. FIG. 9A shows a case where the step is 2 cm, and FIG. 9B shows a case where the step is 4 cm. The horizontal axis of FIG. 9 is a sample number for identifying the wheelchair from which data was measured. Also, the diamonds in FIG. 9 are before normalization, and the circles are after normalization.

  FIG. 10 is a table summarizing the graph shown in FIG. As shown in FIG. 10, in the case of a step of 2 cm, the average value μ after normalization is changed from 28.4 to 12.8, the standard deviation σ is changed from 6.98 to 2.50, and the variation coefficient cv is 0.246. From 0.195 to 0.195. Even in the case of a 4 cm step, the normalized average value μ decreases from 44.7 to 19.8, the standard deviation σ decreases from 10.0 to 3.06, and the coefficient of variation cv decreases from 0.225 to 0.155. ing. Here, the variation coefficient is obtained by dividing the standard deviation by the average value, and the degree of variation can be evaluated using this value. It can be determined that the smaller the variation coefficient, the smaller the variation, and the larger the variation coefficient, the greater the variation.

  Therefore, normalization can reduce variations due to wheelbase differences in the wheelchair 100. Therefore, the accuracy (reliability) of the level difference determination can be improved.

  Next, operations of the arithmetic device 1 and the server device 50 configured as described above will be described with reference to the flowcharts of FIGS. 11 and 12. FIG. 11 is a flowchart of the operation of the arithmetic device 1.

  First, in step S101, threshold values T1, T2, T3, and T4 are set in the level difference detection unit 13, and the process proceeds to step S102. The threshold values T3 and T4 are threshold values set for the vertical acceleration detected by the acceleration sensor 3. The threshold value T3 is a threshold value for detecting that the front wheel 101 has passed the step, and the threshold value T4 is a threshold value for detecting that the rear wheel 102 has passed the step. The threshold values T1 and T2 are threshold values set to the pitch rate detected by the gyro sensor 4. The threshold value T1 is a threshold value for detecting that the front wheel 101 has passed the step, and the threshold value T2 is a threshold value for detecting that the rear wheel 102 has passed the step. These threshold values T1, T2, T3, and T4 can be adjusted in accordance with the wheelchair 100. Alternatively, a data table corresponding to the wheelchair type may be prepared in advance, and the threshold values T1, T2, T3, T4 and the wheel base length H may be automatically set by inputting the wheelchair type.

  Next, in step S102, the vertical acceleration Az and the pitch rate Pr are detected, and the process proceeds to step S103. In this step, the acceleration acquisition unit 12 acquires the vertical acceleration Az detected by the acceleration sensor 3, and the pitch rate acquisition unit 11 acquires the pitch rate Pr detected by the gyro sensor 4. That is, the pitch rate Pr acquired in this step is the first pitch rate.

  Next, in step S103, the level difference detection unit 13 determines whether the vertical acceleration Az acquired in step S102 is less than −T3 and the pitch rate Pr is less than −T1, and if this condition is satisfied (in the case of Yes), The process proceeds to step S104, and if the condition is not satisfied (No), the process proceeds to step S105. In this step, the point b in FIGS. 7A and 7C is detected. The vertical acceleration Az to be compared with the threshold after this step is a value obtained by subtracting the gravitational acceleration, and the threshold is also defined by the change from the gravitational acceleration. That is, the threshold T3 is the third threshold, and the threshold T1 is the first threshold. It is also detected that the signs of the vertical acceleration Az and the pitch rate Pr are negative (negative numbers).

  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, the state corresponding to the point b in FIGS. 7A and 7C is detected, but since the determination on the rear wheel 102 side is not performed, a tentative determination is performed and calculated as a flag indicating the determination. A step candidate flag set in the apparatus 1 is set. 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 the vertical acceleration Az acquired in step S102 is equal to or greater than T3 and the pitch rate Pr is equal to or greater than T1, and if this condition is satisfied (in the case of Yes), step S106 is performed. If the condition is not satisfied (in the case of No), it is determined that the step is not detected, and this flowchart is ended. In this step, the point b in FIGS. 5A and 5C is detected. That is, it is also detected that the signs of the vertical acceleration Az and the pitch rate Pr are positive (positive numbers).

  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, a state corresponding to point b in FIGS. 5 (a) and 5 (c) is detected, but since the determination on the rear wheel 102 side is not performed, a temporary determination is performed, and a step candidate is obtained as in step S104. Set the flag. 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, the vertical acceleration Az and the pitch rate Pr after moving the wheel base length H are detected, and the process proceeds to step S108. In this step, as in step S102, the acceleration acquisition unit 12 acquires the vertical acceleration Az detected by the acceleration sensor 3, and the pitch rate acquisition unit 11 acquires the pitch rate Pr detected by the gyro sensor 4. 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. In this step, the vertical acceleration Az and the pitch rate Pr are detected within a predetermined range (predetermined range) before and after the distance of the wheel base length H. That is, a predetermined range (predetermined range) before and after the distance of the wheel base length H is a distance related to the wheel base length of the mobile body (wheelchair 100). The pitch rate Pr acquired in step S108 is the second pitch rate.

  Next, in step S108, the level difference detection unit 13 determines whether the vertical acceleration Az acquired in step S107 is less than −T4 and the pitch rate Pr is equal to or greater than T2, and if this condition is satisfied (in the case of Yes), the step is performed. The process proceeds to S109, and if the condition is not satisfied (No), the process proceeds to Step S111. In this step, a point c in FIGS. 7A and 7C is detected. That is, the threshold value T4 is the fourth threshold value, and the threshold value T2 is the second threshold value. It is also detected that the sign of the vertical acceleration Az is negative (negative number) and the sign of the pitch rate Pr is positive (positive number).

  Next, in step S109, 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 S110. If not (in the case of No) ) Determines that the step is not detected, and the present flowchart is terminated.

  Next, in step S110, since the step candidate flag indicates a down step, the conditions of points b and c in FIG. 7 are satisfied, and the step detection unit 13 determines that the step that has passed is a down step. A formal determination is made and the process proceeds to step S114. That is, the absolute value of the first pitch rate is greater than or equal to the first threshold (T1), and the absolute value of the second pitch rate is greater than or equal to the second threshold (T2). The absolute value of the vertical acceleration acquired when the first pitch rate is detected is equal to or greater than the third threshold (T3), and the absolute value of the vertical acceleration acquired when the second pitch rate is detected is the fourth threshold. (T4) or more. And the level | step difference is detected based on these conditions. Further, since the first pitch rate is a negative number and the second pitch rate is a positive number, the step that has passed is a downward step. That is, the down step is detected based on the code of the first pitch rate and the code of the second pitch rate.

  On the other hand, in step S111, the level difference detection unit 13 determines whether the vertical acceleration Az acquired in step S107 is equal to or greater than T4 and the pitch rate Pr is less than -T2, and if this condition is satisfied (in the case of Yes), the step is performed. The process proceeds to S112, and when the condition is not satisfied (in the case of No), it is determined that the step is not detected, and this flowchart is ended. In this step, the point c in FIGS. 5A and 5C is detected. That is, it is also detected that the sign of the vertical acceleration Az is positive (positive number) and the sign of the pitch rate Pr is negative (negative number).

  Next, in step S112, the level difference determination 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 S113, and if not (in the case of No). It is determined that the step is not detected, and this flowchart is ended.

  Next, in step S113, since the step candidate flag indicates an up step, the conditions of points a and c in FIG. 5 are satisfied, and the step determination unit 13 determines that the step that has passed is an up step. A formal determination is made and the process proceeds to step S114. That is, the absolute value of the first pitch rate is greater than or equal to the first threshold (T1), and the absolute value of the second pitch rate is greater than or equal to the second threshold (T2). The absolute value of the vertical acceleration acquired when the first pitch rate is detected is equal to or greater than the third threshold (T3), and the absolute value of the vertical acceleration acquired when the second pitch rate is detected is the fourth threshold. (T4) or more. And the level | step difference is detected based on these conditions. Further, since the first pitch rate is a positive number and the second pitch rate is a negative number, the step that has passed is an ascending step. That is, the up step is detected based on the code of the first pitch rate and the code of the second pitch rate.

  Next, in step S114, 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.

  Next, in step S115, the level difference detection unit 13 detects the peak value of the pitch rate Pr of the place (position) determined to be a level difference, and proceeds to step S116. For the peak value of the pitch rate Pr, the values used in the determinations in steps S103, S105, S108, S111, etc. may be stored in an internal memory or the like and used. The peak value detected in this step may be the peak value on the front wheel 101 side (when judging steps S103 and S105) or the peak value on the rear wheel 102 side (when judging steps S108 and S111). Or the average of both.

  Next, in step S116, the level difference determination unit 13 normalizes by multiplying the reciprocal of the wheelbase length H of the wheelchair 100 by the peak value of the pitch rate Pr detected in step S115, and proceeds to step S117. The normalized peak value is defined as a normalized pitch rate Pr_n. That is, the normalized pitch rate Pr_n becomes normalized pitch rate information. Here, the normalized pitch rate Pr_n is the first normalized pitch rate when the peak value on the front wheel 101 side is used in step S115, and the second normalized pitch rate when the rear wheel 102 side is used. When the average of the peak value on the side and the peak value on the rear wheel 102 side is used, the average normalized pitch rate is obtained.

  Next, in step S117, the level difference determination unit 13 adds the ID of the wheelchair 100, and transmits the position determined as the level difference (level difference position Sp) and the normalized pitch rate value Pr_n to the server device 50 via the communication device 5. . The ID of the wheelchair 100 is an ID given in advance for each wheelchair and is set in the computing device 1.

  As apparent from the above description, the flowchart of FIG. 11 shows the first pitch rate that is the pitch rate detected by the pitch rate detecting means when the front wheel 101 passes on the road surface, and the position at which the first pitch rate is detected. It functions as a step detecting step for detecting a step based on the second pitch rate which is the pitch rate detected by the pitch rate detecting means when the rear wheel 102 passes.

  Next, the operation of the server device 50 shown in FIG. 12 will be described. The arithmetic unit 52 executes the flowchart shown in FIG.

  First, in step S <b> 201, the arithmetic device 52 reads the wheelchair 100 ID received by the communication device 51 and acquires the weighting value W of the wheelchair 100. Then, the arithmetic unit 52 averages the normalized pitch rate value Pr_n at the step position Sp received by the communication device 51 with the past data using W (after considering), and proceeds to step S202. The value calculated by the averaging process is set as an average value Pr_ave.

  The weighting value W indicates the reliability of the normalized pitch rate value Pr_n 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 normalized pitch rate information 531 in the storage device 53 in which past data is stored.

  Next, in step S202, the arithmetic unit 52 changes the weighting value W for the wheelchair 100 of the ID received in step S201, and proceeds to step S203. In this step, when the difference between the normalized pitch rate values Pr_n received by the communication device 51 with respect to the average value Pr_ave is large, the weighting value W of the wheelchair 100 is decreased by a predetermined amount. When the difference between the normalized pitch rate value Pr_n received by the communication device 51 with respect to the average value Pr_ave is small, the weighting value W of the wheelchair 100 is increased by a predetermined amount. That is, the wheelchair that outputs the normalized pitch rate value Pr_n close to the average value Pr_ave increases the weighting value W.

  Next, in step S203, the level determination unit 521 of the arithmetic device 52 compares the step level threshold with the average value Pr_ave calculated in step S202, determines the step level, and proceeds to step S204. This threshold is set in advance in accordance with the step level, for example, 5 cm, 10 cm, and the like. For example, when the calculated average value Pr_ave is 6.8 cm, it is in the range of 5 cm to less than 10 cm. Judged as level 2 or the like.

  Next, in step S204, the update unit 522 of the arithmetic device 52 creates or updates barrier information stored in the map information 532 of the storage device 53 based on the level difference result determined in step S203 (barrier free). Create or update a map).

  As described above, the step level determination requires a peak value of the pitch rate. However, if the level difference is merely determined, the peak value may not be used, and each threshold value T1, T2, T3, The determination may be made when a value equal to or greater than T4 is detected.

  Further, in the above-described flowchart, the threshold values for determining the ascending step and the descending step are the same absolute values (T1 and -T1 etc.) having different polarities, but different threshold values may be set. As described above, when the front wheel 101 and the rear wheel 101 pass the ascending step U, the vertical acceleration increases and then starts to decrease because the wheel collides with the step and rises to a position higher than the upper surface of the step. The reason is that when the front wheel 101 and the rear wheel 101 pass through the descending step D, the vertical wheel speed decreases and the increase starts after the wheel collides with the ground. It is. Therefore, if different threshold values are set for the vertical acceleration changes and determined, it is possible to detect the ascending step and the descending step with higher accuracy.

  According to the present embodiment, the computing device 1 is mounted on a wheelchair 100 that includes a front wheel 101 and a rear wheel 102. Then, when the front wheel 101 passes on the road surface, the gyro sensor 4 detects the pitch rate acquired by the pitch rate acquisition unit 11, and the rear wheel 102 passes the position where the first pitch rate is detected. The pitch rate acquired by the gyro sensor 4 and acquired by the pitch rate acquisition unit 11 is set as the second pitch rate, and the step detection unit 13 detects the step based on the first pitch rate and the second pitch rate. ing. By doing so, the step can be detected by the change in the pitch rate of the two wheels, the front wheel 101 and the rear wheel 102, so that the step on the road surface can be accurately detected even if the step is relatively low. Can do.

  In addition, the step detection unit 13 is configured so that the wheelchair 100 has a predetermined range before and after a position moved from a position on the road surface where the first pitch rate is detected, including a predetermined range before and after the distance of the wheelbase length H of the wheelchair 100. The pitch rate acquired by the pitch rate acquisition unit 11 when moving is the second pitch rate. By doing in this way, the position which detects the 2nd pitch rate can be specified based on wheelbase length H which is the length between the front wheel 101 and rear wheel 102 of wheelchair 100 and is a known value. it can.

  Further, when the absolute value of the first pitch rate is equal to or greater than the threshold value T1 and the absolute value of the second pitch rate is equal to or greater than the threshold value T3, the level difference detection unit 13 detects the position as a level difference. 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.

  Moreover, the acceleration acquisition part 12 which acquires the vertical acceleration detected by the acceleration sensor 3 which detects the acceleration of a perpendicular direction with respect to the moving plane of the wheelchair 100 is provided, and the level | step difference detection part 13 is the time of detecting a 1st pitch rate. The step is detected based on the vertical acceleration acquired by the acceleration acquisition unit 12 and the vertical acceleration acquired by the acceleration acquisition unit 12 when the second pitch rate is detected. In this way, since the acceleration in the vertical direction can be taken into consideration in addition to the pitch rate, the step detection accuracy can be further improved.

  In addition, the step detection unit 13 acquires the absolute value of the vertical acceleration acquired by the acceleration acquisition unit 12 when the first pitch rate is detected and the acceleration acquisition unit 12 acquires the second pitch rate when the absolute value of the vertical acceleration is greater than or equal to the threshold T3. When the absolute value of the vertical acceleration is equal to or greater than the threshold T4, the position is detected as a step. By doing so, the first pitch rate can be set when the vertical acceleration of a certain level or more is detected when passing through the front wheel 101 and when passing through the rear wheel 102, and the detection of the step can be made with high accuracy. it can.

  Further, the step detection unit 13 detects a step based on the sign of the pitch rate acquired from the gyro sensor 4 and the direction of change in vertical acceleration acquired by the acceleration acquisition unit 12. By doing so, it is possible to consider the sign of the pitch rate, that is, whether the pitch rate is positive or negative, and the sign of acceleration, that is, whether the acceleration has increased or decreased. In addition, it is possible to detect the step with high accuracy in consideration of the direction of acceleration and acceleration.

  Further, the step detection unit 13 detects whether the step through which the wheelchair 100 has passed is an up step or a down step based on the sign of the first pitch rate and the sign of the second pitch rate. In this way, it is possible to determine whether the step that has passed through the sign of the two pitch rates is an up step or a down step.

  Further, when detecting the level difference, the level difference detection unit 13 generates a normalized pitch rate Pr_n in which the peak value of the pitch rate Pr is normalized by the wheelbase length H. Then, the level difference detection unit 13 acquires the latitude and longitude of the position where the level difference is detected from the GPS receiver 2. Then, as information for the communication device 5 to determine the level of the step on the road surface by the server device 50, the normalized pitch rate Pr_n and the ID of the wheelchair 100 are added to the latitude and longitude of the position where the step is detected. It is transmitted to the server device 50. In this way, by calculating the normalized pitch rate Pr_n, the detection error due to the difference in the wheel base length H can be reduced. Further, the server device 50 can accumulate the result of determining the level difference based on the information collected from the plurality of level difference detection devices. Therefore, the determination accuracy of the step can be increased.

  The computing device 52 of the server device 50 determines the level difference after weighting the normalized pitch rate Pr_n transmitted from the wheelchair 100 (the computing device 1) based on the weighting value W. By doing so, it is possible to reduce the step level from fluctuating due to low reliability data, and to improve the reliability of the step level.

  In the embodiment described above, the step level is determined by the server device 50, but the determination may be performed by the computing device 1 mounted on the wheelchair 100 based on the normalized pitch rate Pr_n. 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 an acceleration 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.

  In the above-described embodiment, the step is detected based on the detection results of both the acceleration sensor 3 and the gyro sensor 4. However, even if only the detection result of the gyro sensor 4 is inaccurate, the step detection is performed although the accuracy is inferior. Is possible. In this case, only threshold values T1 and T2 need be set.

  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.

  Further, in the above-described embodiments, the wheelchair is described as the moving body. However, senior cars, baby carriages, golf carts, bicycles, automobiles, carriages, robots having wheels, etc., are provided with front and rear wheels for traveling on the road surface. That's fine.

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

Claims (13)

A step detection device mounted on or attached to a moving body including a front wheel and a rear wheel,
Step detection that acquires a pitch rate detected by a pitch rate detection unit that detects a pitch rate of the moving body, and detects a step on the road surface on which the moving body travels and passes based on the acquired pitch rate. With means,
The step detecting means includes a first pitch rate which is a pitch rate detected by the pitch rate detecting means when the front wheel passes on the road surface, and the rear wheel passes a position where the first pitch rate is detected. Detecting the step based on the second pitch rate that is the pitch rate detected by the pitch rate detecting means when
A step detecting device characterized by the above.   The level difference detecting means uses the second pitch rate detected when the moving body moves a distance related to the wheel base length of the moving body from the position on the road surface where the first pitch rate is detected. The step detection device according to claim 1, wherein a pitch rate is set.   The step detecting means determines the position when the absolute value of the first pitch rate is equal to or greater than a predetermined first threshold value and the absolute value of the second pitch rate 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. An acceleration acquisition means for acquiring an acceleration detected by an acceleration detection means for detecting an acceleration in a direction perpendicular to a moving plane of the moving body;
The step detection means is based on the acceleration acquired by the acceleration acquisition means when the first pitch rate is detected and the acceleration acquired by the acceleration acquisition means when the second pitch rate is detected. Detect steps,
The level difference detecting device according to any one of claims 1 to 3, wherein   The step detecting means detects the second pitch rate when the absolute value of the acceleration acquired by the acceleration acquiring means is greater than or equal to a predetermined third threshold when the first pitch rate is detected and the second pitch rate is detected. The level difference detection device according to claim 4, wherein when the absolute value of the acceleration acquired by the acceleration acquisition unit is equal to or greater than a predetermined fourth threshold value, the position is detected as a level difference.   The step detection means detects the step based on the sign of the pitch rate acquired from the pitch rate detection means and the direction of change of acceleration acquired by the acceleration acquisition means. 5. The level difference detection device according to 5.   The step detecting means detects whether the step passed by the moving body is an up step or a down step based on the sign of the first pitch rate and the sign of the second pitch rate. The level | step difference detection apparatus as described in any one of Claim 1 thru | or 6. The step detecting means detects a first normalized pitch rate obtained by normalizing a peak value of the first pitch rate by the wheelbase length and / or a peak value of the second pitch rate when the step is detected. Generating normalized pitch rate information based on a second normalized pitch rate normalized by the wheelbase length;
Position acquisition means for acquiring information regarding the position where the step is detected;
Transmission for transmitting to the server device information relating to the position where the step acquired by the position acquisition means and the normalized pitch rate information are transmitted as information for determining the level of the step on the road surface by an external server device Means,
The step detecting device according to any one of claims 2 to 7, further comprising:   The step detecting means detects a first normalized pitch rate obtained by normalizing a peak value of the first pitch rate by the wheelbase length and / or a peak value of the second pitch rate when the step is detected. The level difference detecting device according to any one of claims 2 to 7, wherein the level difference level is determined based on a second normalized pitch rate normalized by the wheel base length. Position acquisition means for acquiring information regarding the position where the step is detected;
Transmitting means for transmitting information related to the step level determined by the step detecting means and the position where the step is detected to an external server device;
The step detecting device according to claim 9, comprising: A step detection method that is executed by a step detection device that is mounted on or attachable to a moving body including a front wheel and a rear wheel,
A step detecting step for acquiring a pitch rate detected by a pitch rate detecting means for detecting a pitch rate of the moving body, and detecting a step on the road surface on which the moving body travels and passes based on the acquired pitch rate. Including
In the step detecting step, the rear wheel passes the first pitch rate which is the pitch rate detected by the pitch rate detecting means when the front wheel passes on the road surface, and the position where the first pitch rate is detected. Detecting the step based on the second pitch rate that is the pitch rate detected by the pitch rate detecting means when
A method for detecting a level difference.   A step detection program that causes the computer to execute the step detection method according to claim 11.   A computer-readable recording medium storing the step detection program according to claim 12.

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