JP2009186376A - Moving direction calculation device and moving direction calculation program - Google Patents

Abstract

An object of the present invention is to calculate a moving direction of a walking body with higher accuracy without using position information.
A moving direction calculation device 110 includes a magnetic sensor 111 that measures geomagnetism according to the position of a walking body 100 and a gyro sensor 112 that measures an angular velocity of a turn when the walking body 100 walks. ing. Then, the moving direction calculation device 110 calculates the moving direction of the walking body 100 by using the sensor output (measurement result) of either the magnetic sensor 111 or the gyro sensor 112 when the walking body 100 is walking. At this time, which sensor output of the magnetic sensor 111 and the gyro sensor 112 is used is determined by referring to the amount of change in the sensor output of each sensor.
[Selection] Figure 1

Description

  The present invention relates to a moving direction calculation apparatus and a moving direction calculation program that are attached to a walking body and calculate the moving direction of the walking body.

  Conventionally, many techniques for autonomously detecting the orientation of a walking body without using an external measurement signal such as a GPS signal have been provided. By using these techniques, it is possible to calculate in which direction the walking body is moving (walking). In order to calculate the moving direction of the moving body, a magnetic sensor or a gyro sensor is attached to the walking body, and the moving direction may be obtained using measurement results obtained from these sensors. At this time, as a judgment criterion of the sensor for detecting the direction of the moving direction, a method using the direction of the geomagnetic sensor vector or a method of comparing the amount of change in the direction of geomagnetism and the amount of change in the direction of the gyro accumulated for a certain period of time is used. there were.

  Specifically, as a technique for detecting the moving direction of the walking body, a technique is disclosed in which a small and lightweight direction detecting means such as a magnetic sensor or a gyro sensor for measuring geomagnetism is used alone (see, for example, Patent Document 1 below). ). Also, compare the angle between the geomagnetic vector and the horizontal plane with the value in the geomagnetic dip database at the current location, and if the error is within a certain range, calculate the direction using the magnetic vector detected by the magnetic sensor as the geomagnetic vector. Is also disclosed (for example, see Patent Document 2 below). As described above, the conventional autonomous movement direction calculation processing generally uses the geomagnetic information detected by the magnetic sensor and the gyro information detected by the gyro sensor when calculating the movement direction of the walking body. is there.

Japanese Patent No. 3532773 Japanese Patent No. 3837533

  However, in the case of the above-mentioned patent document 1, in order to determine how reliable the geomagnetic information is, it is necessary to have a determination table that defines a criterion for determining reliability for each place where the magnetic sensor is used. . At the time of measurement, it is necessary to read out and use the position information obtained from the GPS signal for the location where the magnetic sensor is used or the position information corresponding to the position information manually selected by the user. Therefore, a process for specifying the current position by the user (for example, a walking body wearing a device having a moving direction calculation function) is essential, and the processing time for selecting the current position before the moving direction calculation process is performed. There was a problem that would be necessary.

  In addition, as in Patent Document 2, in the method of comparing the geomagnetic azimuth change accumulated for a certain period of time and the gyro azimuth change, the change in the body direction due to the stepping action of the user's walking foot is included in the azimuth change. It will be. Therefore, there is a problem that it is difficult to compare the geomagnetic azimuth change amount and the gyro azimuth change amount.

  In addition, when the magnetic sensor is measured in a place where the geomagnetism is disturbed compared to other places such as inside a reinforced concrete building, distribution board, and elevator, these external factors affect the measurement result and move. The direction calculation error becomes large. Therefore, even if the magnetic quantity measured by the magnetic sensor and the reliability of the geomagnetism are determined from the change in the magnetic quantity, it is difficult to calculate a highly reliable azimuth as the moving direction using the measurement result of the angular velocity sensor. There was a problem of being.

  The present invention provides a moving direction calculation device and a moving direction calculation program capable of calculating the moving direction of a walking body with higher accuracy without using position information in order to eliminate the above-described problems caused by the prior art. The purpose is to do.

  In order to solve the above-described problems and achieve the object, the movement direction calculation apparatus and the movement direction calculation program are a movement direction calculation apparatus and a movement direction calculation program that are attached to a walking body and calculate the movement direction of the walking body. An acceleration sensor that measures acceleration accompanying movement of the walking body, a gyro sensor that measures angular velocity associated with turning of the walking body, and a magnetic sensor that measures geomagnetism according to the position of the walking body. , Detecting the walking interval of the walking body from the measurement result of the acceleration sensor, and determining from the amount of change in orientation obtained from the measurement result of the gyro sensor during the detected walking interval and the measurement result of the magnetic sensor The difference between the measured change amount of the azimuth is calculated, and according to the calculated difference, one of the measurement result of the gyro sensor and the measurement result of the magnetic sensor. Select the measurement results, it is a requirement to include a process of calculating the movement direction of the walking body in the walking distance by using the measurement results of the selected.

  According to the moving direction calculation device and the moving direction calculation program, the amount of change in azimuth obtained from the measurement result of the gyro sensor and the amount of change of azimuth obtained from the measurement result of the magnetic sensor for each walking interval of the walking body It is determined how accurate the measurement result of the magnetic sensor is from the difference between the two, and the moving direction is calculated using the measurement result of the magnetic sensor only when the measurement result of the magnetic sensor has a predetermined accuracy or more. . Therefore, since the measurement result with higher reliability is selected from the measurement results, the moving direction of the walking body can be calculated with high accuracy.

  In the movement direction calculation device and the movement direction calculation program, the measurement result of the magnetic sensor may be selected when the calculated difference falls within a predetermined range.

  According to the moving direction calculation device and the moving direction calculation program, if the amount of change in orientation obtained from the measurement results of the gyro sensor and the magnetic sensor is small, it is determined that the measurement result of the magnetic sensor is accurate, and the movement It can be used for direction calculation.

  In the above moving direction calculation device and moving direction calculation program, the reliability of the measurement result of the magnetic sensor is calculated according to the fluctuation range of the measurement result of the magnetic sensor, and the calculated reliability is less than the threshold value. In this case, the moving direction may be calculated by selecting the measurement result of the gyro sensor.

  According to the moving direction calculation device and the moving direction calculation program, when the reliability of the magnetic sensor is low, the moving direction is calculated using the measurement result of the gyro sensor without comparing the azimuth change amount. Can do.

  The movement direction calculation device and the movement direction calculation program are a movement direction calculation device and a movement direction calculation program that are attached to a walking body and calculate the movement direction of the walking body, and are provided with accelerations associated with the movement of the walking body. An acceleration sensor for measuring, a gyro sensor for measuring an angular velocity associated with the turning of the walking body, and a magnetic sensor for measuring geomagnetism according to the position of the walking body, and the fluctuation range of the measurement result of the magnetic sensor Accordingly, the reliability of the measurement result of the magnetic sensor is calculated, the walking interval of the walking body is detected from the measurement result of the acceleration sensor, and the measurement of the magnetic sensor is performed when the calculated reliability is equal to or greater than a threshold value When the result is less than the threshold value, the measurement result of the gyro sensor is selected, and the movement of the walking body in the walking interval is selected using the selected measurement result. It is a requirement to include a process of calculating the direction.

  According to the moving direction calculation apparatus and the moving direction calculation program, it is possible to determine which measurement result of the gyro sensor or the magnetic sensor is used from the reliability of the magnetic sensor and the amount of change in the measurement result of the gyro sensor. .

  In the movement direction calculation device and the movement direction calculation program, when the measurement result of the gyro sensor is selected, the measurement result of the gyro sensor is added to the movement direction calculated during the previous walking interval. Then, the moving direction of the walking body may be calculated.

  According to the moving direction calculation device and the moving direction calculation program, when using the measurement result of the gyro sensor, the moving direction can be calculated more accurately by referring to the calculation result in the previous walking interval.

  According to the moving direction calculation device and the moving direction calculation program, there is an effect that the moving direction of the walking body can be calculated with higher accuracy without using position information.

  Exemplary embodiments of a moving direction calculating device and a moving direction calculating program will be described below in detail with reference to the accompanying drawings.

(Overview of moving direction calculation process)
First, an outline of the movement direction calculation process according to the present embodiment will be described. FIG. 1 is an explanatory diagram showing an outline of the movement direction calculation process. As shown in FIG. 1, the walking body 100 is equipped with a small moving direction calculation device 110. The moving direction calculation device 110 is equipped with a magnetic sensor 111 that measures geomagnetism according to the position of the walking body 100 and a gyro sensor 112 that measures the angular velocity of turning when the walking body 100 walks.

  The moving direction calculation device 110 calculates the moving direction of the walking body 100 by using the sensor output (measurement result) of either the magnetic sensor 111 or the gyro sensor 112. At this time, which sensor output of the magnetic sensor 111 and the gyro sensor 112 is used is determined by referring to the amount of change in the sensor output of each sensor.

  Hereinafter, a specific configuration of the moving direction calculation device 110 and how to determine whether to adopt the sensor output of the magnetic sensor 111 and the gyro sensor 112 based on the change amount of the sensor output will be described.

(Hardware configuration of moving direction calculation device)
Next, a hardware configuration of the moving direction calculation apparatus 110 according to the present embodiment will be described. FIG. 2 is a block diagram illustrating a hardware configuration of the moving direction calculation apparatus. As shown in FIG. 1, the moving direction calculation device 110 is a small device of a cigarette box size. Further, the moving direction calculation device 110 may be an existing terminal such as a PDA (Personal Digital Assistant) or a PC (Personal Computer) added with a hardware configuration described below, or includes a dedicated housing. It may be a device.

  Further, the movement direction calculating device 110 includes a CPU 201, a ROM 202, a RAM 203, an HDD (hard disk drive) 204, an HD (hard disk) 205, a memory drive 206, and a removable memory 207 as a removable recording medium. , A display 208, an input I / F (interface) 209, various sensors 210, and a network I / F 211. Each component is connected by a bus 220.

  Here, the CPU 201 governs overall control of the movement direction calculation device 110. The ROM 202 stores a program such as a boot program. The RAM 203 is used as a work area for the CPU 201. The HDD 204 controls data read / write with respect to the HD 205 according to the control of the CPU 201. The HD 205 stores data written under the control of the HDD 204.

  The memory drive 206 controls reading / writing of data with respect to the removable memory 207 according to the control of the CPU 201. The removable memory 207 stores data written under the control of the memory drive 206 or causes the memory drive 206 to read data stored in the removable memory 207 under the control of the CPU 201.

  The display 208 displays data related to the movement direction calculation result using a document, an image, as well as a cursor, an icon, or a tool box. As the display 208, for example, a CRT, a TFT liquid crystal display, a plasma display, or the like can be adopted.

  The input I / F 209 includes keys for inputting characters, numbers, various instructions, and the like, and inputs data. Moreover, a touch panel type input pad or a numeric keypad may be used. The input unit of the input I / F 209 may be a pointing device such as a touch panel or a trackball.

  The various sensors 210 are composed of sensors having different functions for measuring information for calculating the moving direction. Specifically, an acceleration sensor for detecting the walking interval of the walking body 100, a magnetic sensor 111 and a gyro sensor 112 for calculating the moving direction of the walking body 100 are mounted.

  The network I / F 211 connects to the network 230 such as the Internet through the communication line 212 regardless of wired wireless, and connects the movement direction calculation device 110 to other devices via the network 230. The network I / F 211 controls an internal interface with the network 230 and controls data input / output from an external device. As the network I / F 211, for example, a modem or a LAN adapter can be employed.

(Functional configuration of moving direction calculation device)
Next, a functional configuration of the moving direction calculation apparatus 110 according to the present embodiment will be described. FIG. 3 is a block diagram illustrating a functional configuration of the moving direction calculation apparatus. As illustrated in FIG. 3, the moving direction calculation device 110 includes a sensor unit 310, an arithmetic processing unit 320, a storage unit 330, a display unit 340, and a communication unit 350.

  The sensor unit 310 includes three types of sensors: an acceleration sensor 311, a magnetic sensor 111, and a gyro sensor 112. The operation content accompanying the movement of the walking body 100 is measured from these sensors. The sensor unit 310 is realized by, for example, the various sensors 210 described with reference to FIG.

  The arithmetic processing unit 320 is a processing unit that obtains the orientation direction of the walking body 100 from the measurement result acquired from the sensor unit 310 by arithmetic processing. The arithmetic processing unit 320 is realized by, for example, the CPU 201, the ROM 202, and the RAM 203 described with reference to FIG.

  The storage unit 330 is a storage area that stores predetermined information according to the control of the CPU 201. The information stored in the storage unit 330 includes input information 331, output information 332, setting parameters 333 necessary for calculation processing, a determination table 334, and a calculation algorithm 335 used for calculation processing. The storage unit 330 is implemented by, for example, the HDD 204, HD 205, memory drive 206, and removable memory 207 described with reference to FIG.

  The display unit 340 and the communication unit 350 function as an output unit that outputs the movement direction calculation result of the walking body 100 calculated by the calculation processing unit 320. In the display unit 340, the moving direction calculation result can be notified to the walking body 100 itself by a display device such as a liquid crystal display. Moreover, since the communication part 350 can transmit a moving direction calculation result to another apparatus and a predetermined address, it can alert | report the moving direction of the walking body 100 with respect to others.

  In addition to the movement direction calculation result, the communication unit 350 can acquire the setting parameter 333, the determination table 334, and the calculation algorithm 335 necessary for calculation in the calculation processing unit 320 from the outside through communication with an external device. it can. The display unit 340 is realized by, for example, the display 208 in FIG. Moreover, the communication part 350 is implement | achieved by network I / F211 of FIG. 2, for example.

(Movement direction calculation procedure)
Next, the movement direction calculation processing by the movement direction calculation device 110 described above will be described. In the present embodiment, the movement direction is roughly calculated by three types of processing. The first is the most basic processing, which is a movement direction calculation device 110 that is attached to the walking body 100 and calculates the movement direction of the walking body, and is obtained from the measurement results of the magnetic sensor 111 and the gyro sensor 112. This is a process of comparing the amount of change in direction and selecting a measurement result used for moving direction calculation according to the accuracy of the magnetic sensor 111.

  Specifically, a gyro (in the walking interval) between the detecting unit that detects the walking interval of the walking body 100 from the measurement result of the acceleration sensor 311 and the walking interval detected by the detecting unit is sent to the arithmetic processing unit 320. According to the difference calculation means for calculating the difference between the azimuth change amount obtained from the measurement result of the sensor 112 and the azimuth change amount obtained from the measurement result of the magnetic sensor 111, and the difference calculated by the difference calculation means, Selection means for selecting either the measurement result of the gyro sensor 112 or the measurement result of the magnetic sensor 111 is provided, and the movement of the walking body 100 at the detected walking interval is detected using the measurement result selected by the selection means. Calculate the direction.

  The second process is a process that measures the reliability of the magnetic sensor 111 before the difference calculation of the first process and uses it for selecting the measurement result. Specifically, the arithmetic processing unit 320 is newly provided with reliability calculation means for calculating the reliability of the measurement result of the magnetic sensor 111 according to the fluctuation range of the measurement result of the magnetic sensor 111. Then, when the reliability calculated by the reliability calculation unit is less than the threshold value, the selection unit selects the measurement result of the gyro sensor 112 and calculates the moving direction of the walking body 100.

  The third process is a process in which the reliability used in the second process described above is used to select a measurement result. Specifically, a reliability calculation means for calculating the reliability of the measurement result of the magnetic sensor 111 in accordance with the fluctuation range of the measurement result of the magnetic sensor 111 in the arithmetic processing unit 320, and the walking body 100 from the measurement result of the acceleration sensor 311. When the reliability calculated by the detection means for detecting the walking interval and the reliability calculation means is greater than or equal to the threshold value, the measurement result of the magnetic sensor 111 is selected. It is a process provided with the selection means which selects a result, and the direction calculation means which calculates the moving direction of the walking body 100 in a walk interval using the measurement result selected by the selection means.

  Thus, in the movement direction calculation apparatus 110 according to the present embodiment, any one of the above three processes is employed to calculate the movement direction of the walking body 100, respectively. Details of these three processes will be described below as first to third embodiments.

(Information acquisition procedure of sensor part)
First, processing common to the processing of the first to third embodiments will be described. In any of the first to third embodiments, the measurement result must be acquired from the sensor unit 310 (see FIG. 3). Here, a procedure for acquiring the measurement result will be described.

  FIG. 4 is a flowchart showing the information acquisition procedure of the sensor unit. In the flowchart of FIG. 4, the moving direction calculation device 110 first acquires the measurement value of the acceleration sensor 311 (step S401). In the process of step S401, the measurement result (acceleration information) acquired from the acceleration sensor 311 is further converted from analog information to digital information by referring to the offset value and gain value of the setting parameter 333 in the storage unit 330 by the arithmetic processing unit 320. And is stored as input information 331.

  Moreover, the moving direction calculation apparatus 110 acquires the measured value of the magnetic sensor 111 similarly to step S401 (step S402). In the process of step S402, the measurement value (magnetic information) acquired from the magnetic sensor 111 is further converted from analog information to digital information by the arithmetic processing unit 320 (similar to the process of step S401) and saved as input information 331. Is done.

  Furthermore, the moving direction calculation apparatus 110 acquires the measurement value of the gyro sensor 112 similarly to steps S401 and S402 (step S403). In the process of step S403, the measurement value (gyro information) acquired from the gyro sensor 112 is further converted from analog information to digital information by the arithmetic processing unit 320 (similar to the process of step S401) and saved as input information 331. Is done. These processes are repeated until an end instruction is received (step S404: No loop). When an end instruction is received (step S404: Yes), a series of processes is ended.

  As described above, in any case of the first to third embodiments, the measurement value is acquired by the procedure as shown in the flowchart of FIG. 4 and the input information 331 is accumulated. Note that the processing order of steps S401 to S403 in the flowchart of FIG. 4 is not limited and may be performed in parallel.

<Example 1>
Next, specific processing contents will be described separately for each of the first to third embodiments. First, Example 1 will be described. In the first embodiment, as described above, it is determined which measurement result is used for calculating the moving direction from the comparison result of the change amounts of the measurement results of the magnetic sensor 111 and the gyro sensor 112.

  FIG. 5 is a flowchart illustrating a procedure of movement direction calculation processing according to the first embodiment. In the flowchart of FIG. 5, it is first determined whether or not a certain period of time has been waited (step S501). Here, after waiting for a predetermined time (step S501: No loop), after waiting for a predetermined time (step S501: Yes), the inclination of the walking body 100 is detected from the acceleration information accumulated in the storage unit 330. (Step S502).

  Next, the orientation of the horizontal plane of the geomagnetic vector is calculated from the magnetic information stored in the storage unit 330 and the inclination of the walking body detected in step S502 (step S503), and the gyro information also stored in the storage unit 330 The amount of rotation of the gyroscope on the horizontal plane is calculated from the inclination of the walking body detected in step S502 (step S504).

  Here, detection of the inclination of the walking body 100 and calculation of the geomagnetic vector will be described. FIG. 6 is an explanatory diagram showing detection values for calculating the inclination of the walking body. As shown in FIG. 6, in order to detect the inclination of the walking body 100, if the acceleration information detected by the sensor axes (X1, Y1, Z1) is (AX1, AY1, AZ1), the earth axes (X, Y, The equation for calculating the slope with Z) is as follows.

Inclination α in the front-rear direction: asin (AX1)
Inclination β in the left-right direction: atan (AY1 / AZ1)

  From the above inclination, if the geomagnetic vector is detected by the sensor axis (X1, Y1, Z1) and the geomagnetic information is (MX1, MY1, MZ1), the geomagnetic information at the earth axis (X, Y, Z). (MX, MY, MZ) can be obtained by the following conversion equation.

MX = MX1 × cos (α) + MY1 × sin (α) × sin (β) + MZ1 × sin (α) × cos (β)
MY = MY1 × cos (β) −MZ1 × sin (β)
MZ = −MX1 × sin (α) + MY1 × cos (α) × sin (β) + MZ1 × cos (α) × cos (β)

  In this way, the orientation of the horizontal plane can be further obtained by the following calculation formula. These calculation formulas are all known techniques and do not limit the calculation method. Also, other calculation formulas may be applied.

  Horizontal plane orientation = atan (MY / MX)

  Returning to the flowchart of FIG. 5, subsequently, gyro rotation amount addition information is calculated from the gyro rotation amount calculated in step S504 (step S505). In the process of step S505, the initial value of the gyro rotation amount addition information is set to 0, and the horizontal plane gyro rotation amount is added to the gyro rotation amount addition information.

  Next, it is determined whether or not the walking body 100 is walking (step S506). In step S506, walking is detected using acceleration information stored and accumulated in the input information 331. Specifically, it is determined from the acceleration information accumulated for a certain period of time whether the current acceleration information is the maximum value of one cycle, and when the acceleration is maximum, it is determined that the user is walking. If it is not determined that the user is walking (step S506: No), the process proceeds to step S516.

  If it is determined in step S506 that the user is walking (step S506: Yes), calculation using the measurement result of the magnetic sensor 111 is performed. First, the change amount of the geomagnetic vector, which is the detection value of the magnetic sensor 111, is calculated (step S507). In step S507, the output information 332 of the storage unit 330 is set as a value when the horizontal plane direction of the geomagnetic vector is the maximum value. save. Then, the difference between the direction of the horizontal plane of the geomagnetic vector at the maximum value at the time of the previous walking detection and the direction of the horizontal plane of the geomagnetic vector at the maximum value at the time of the current walking detection is set as the amount of geomagnetic change.

  Next, an azimuth change amount based on the geomagnetic vector is calculated (step S508). In this step S508, the geomagnetic change amount at the time of the current walking detection and the average of the geomagnetic change amount at the maximum value at the previous walking detection time are set as the geomagnetic direction change amount.

  Next, calculation using the measurement result of the gyro sensor 112 is performed. First, the amount of change in the calculated value of the gyro sensor 112 is calculated (step S509). In step S509, the addition information obtained by adding the rotation amount of the gyro sensor 112 is used as the gyro change amount. At this time, when the calculation process is performed for the first time, the addition information of the rotation amount of the gyro sensor 112 is initialized.

  Next, the amount of change in orientation obtained from the measurement result of the gyro sensor 112 is calculated (step S510). In this step S510, the azimuth change amount by the gyro sensor 112 at the time of the current walking detection and the average of the azimuth change amount by the gyro sensor 112 at the time of the maximum value at the previous walking detection time are calculated and set as the gyro azimuth change amount. .

  When the above calculation process is completed, the difference between the azimuth change amount obtained from the measurement result of the magnetic sensor 111 and the azimuth change amount obtained from the measurement result of the gyro sensor 112 is calculated (step S511). Then, it is determined whether or not the change amount calculated in step S511 is within a preset threshold value (step S512). As the threshold value, for example, “whether it is within 5 degrees / second” is set.

  In step S512, when the difference in the amount of change is within a preset threshold value (step S512: Yes), the measurement result of the magnetic sensor 111 is determined to be accurate, and the walking object 100 is determined using the geomagnetic vector. Is calculated (step S513). That is, the direction of the walking body 100 is calculated from the direction of the horizontal plane of the geomagnetic vector and is set as the moving direction.

  On the other hand, if the difference in the amount of change does not fall within the preset threshold value in step S512 (step S512: No), it is determined that the measurement result of the magnetic sensor 111 is not accurate, and the measurement result of the gyro sensor 112 is used. Then, the azimuth of the walking body 100 is calculated (step S514). That is, the gyro azimuth change amount is added to the azimuth calculated at the time of the previous walking detection to calculate the body direction of the walking body 100 and set it as the movement direction.

  When the moving direction is calculated in step S513 or step S514, the calculated information is transmitted to a predetermined destination by the communication unit 350 (see FIG. 3) (step S515). Then, it is determined whether or not an end instruction from the CPU 201 has been received (step S516), and the processes of steps S501 to S515 described above are repeated until the end instruction is received (step S516: No loop). When an end instruction is received (step S516: Yes), a series of processing ends.

  As described above, in the first embodiment, the vertical motion of the walking body 100 is detected by the acceleration sensor 311 and the timing of one step is calculated. Therefore, the magnetic sensor 111 and the gyro sensor 112 can calculate and store the geomagnetic azimuth change amount and the gyro azimuth change amount for each step. In this way, in order to remove the direction of the body due to the stepping action of the foot during walking, the geomagnetic azimuth change amount and gyro azimuth change amount accumulated at the previous one-step timing and the current one-step timing are accumulated. Since the average value of the calculated geomagnetic azimuth change and gyro azimuth change is calculated and stored, the moving direction can be calculated more accurately.

  If the difference between the average value of the geomagnetic azimuth change amount and the average value of the gyro azimuth change amount is within the threshold range, it is determined that the geomagnetism is stable, and the moving direction is calculated by detecting the direction using the geomagnetism. . If the difference between the average value of the geomagnetic azimuth change and the average value of the gyro azimuth change is outside the threshold range, it is determined that the geomagnetism is not stable, and the measurement result of the magnetic sensor 111 is not used. The direction of movement is calculated by adding the rotation amount detected by the gyro sensor 112 to the last calculated direction.

<Example 2>
Next, Example 2 will be described. In Example 2, the reliability of the measurement result of the magnetic sensor 111 is newly obtained, and which measurement result is used is determined. In addition, description of the part which overlaps with the process of Example 1 is abbreviate | omitted here, and Example 2 original process is demonstrated.

  FIG. 7-1 is a flowchart illustrating a procedure of movement direction calculation processing according to the second embodiment. In the flowchart of FIG. 7A, the same processing as in the first embodiment is performed from step S701 to step S711. When the process of step S711 is completed, the geomagnetic reliability is then calculated (step S712). In this step S712, a value obtained by calculating the difference between the geomagnetic vector at the time of the current walking detection and the geomagnetic vector at the time of the previous walking detection on the three axes of the X axis, the Y axis, and the Z axis (see FIG. 6) And

  Then, it is determined whether or not the difference in the azimuth variation obtained in step S711 is within a predetermined threshold (step S713), and whether the geomagnetic reliability calculated in step S712 is within a preset threshold. Is determined (step S714). FIG. 7-2 is a chart illustrating an example of threshold values in the movement direction calculation processing according to the second embodiment. As an example, the threshold may be determined by setting as shown in FIG.

  When the difference in azimuth change amount does not fall within the threshold value (step S713: No) or the geomagnetic reliability does not fall within the threshold value (step S714: No), the measurement result of the magnetic sensor 111 is not accurate. The azimuth of the walking body 100 is calculated using the measurement result of the gyro sensor 112 (step S716). That is, the gyro azimuth change amount is added to the azimuth calculated at the time of the previous walking detection to calculate the body direction of the walking body 100 and set it as the movement direction.

  On the other hand, when the difference in azimuth change amount is within the threshold value (step S713: Yes) and the geomagnetic reliability is within the threshold value (step S714: Yes), the measurement result of the magnetic sensor 111 is accurate. The azimuth | direction of the walking body 100 is calculated using a geomagnetic vector (step S715). That is, the direction of the walking body 100 is calculated from the direction of the horizontal plane of the geomagnetic vector and is set as the moving direction.

  When the determinations in steps S715 and S716 are completed, the calculation information is transmitted to a predetermined destination by the communication unit 350 (see FIG. 3) as in the first embodiment (step S717). Then, it is determined whether or not an end instruction from the CPU 201 has been received (step S718), and the above-described processing of steps S701 to S717 is repeated until an end instruction is received (step S718: No loop). When an end instruction is received (step S718: Yes), a series of processing ends.

  As described above, in the second embodiment, in addition to the processing of the first embodiment, the geomagnetic reliability calculated from the temporal change in the magnitude of the geomagnetic vector is used to determine whether or not the magnetic sensor 111 is accurate. If the difference between the average value of the geomagnetic azimuth change and the average value of the gyro azimuth change is within the threshold range and the geomagnetic reliability is within the threshold range, the geomagnetism is stable. And the moving direction is calculated using the measurement result of the magnetic sensor 111.

  In addition, if the difference between the average value of the geomagnetic azimuth change and the average value of the gyro azimuth change is outside the threshold range and the geomagnetic reliability is outside the threshold range, the geomagnetism is stable. Therefore, the measurement result of the magnetic sensor 111 is not used, and the movement direction is calculated by adding the rotation amount obtained from the measurement result of the gyro sensor 112 to the movement direction calculated last.

<Example 3>
Finally, Example 3 will be described. In the third embodiment, the measurement result is selected from the reliability calculation result. Again, description of the same processing as in the first and second embodiments is omitted.

  FIG. 8A is a flowchart illustrating the procedure of the moving direction calculation process according to the third embodiment. In the flowchart of FIG. 8A, the processes in steps S801 to S808 are performed in the same manner as in the first or second embodiment. However, in the case of the third embodiment, the geomagnetic change amount calculation (steps S507 and 707), the geomagnetic azimuth change calculation (steps S508 and 708) in the first and second embodiments, and the difference calculation of the azimuth change amount (steps S511 and 711). ) Is omitted. Then, similarly to the second embodiment, the geomagnetic reliability is calculated (step S809).

  When the geomagnetic reliability is calculated in step 809, it is determined whether or not the geomagnetic reliability is within a preset threshold value (step S810). Here, when the geomagnetic reliability is within a preset threshold value (step S810: Yes), it is determined that the geomagnetism is stable, and the moving direction is calculated using the measurement result of the magnetic sensor 111 (step). S811).

  On the other hand, when the geomagnetic reliability does not fall within the preset threshold value (step S810: No), it is further determined whether or not the amount of change in orientation obtained from the measurement result of the gyro sensor 112 is less than or equal to the threshold value ( Step S812). Here, when the amount of change in orientation is equal to or less than the threshold value (step S812: Yes), it is determined that the measurement result of the gyro sensor 112 is not accurate, and this time is calculated without calculating the moving direction this time. The moved direction is output as it is (step S813).

  On the other hand, when the amount of change in the azimuth is higher than the threshold (step S812: No), the measurement result of the gyro sensor 112 is used in the last calculated movement direction in order to use the measurement result of the gyro sensor 112. The amount of rotation obtained from the above is added to calculate the moving direction (step S814). FIG. 8-2 is a chart illustrating an example of threshold values in the movement direction calculation processing according to the third embodiment. As an example, the threshold may be determined by setting as shown in FIG.

  When the determinations in steps S811, S813, and S814 are completed, the calculation information is transmitted to a predetermined destination by the communication unit 350 (see FIG. 3) as in the first and second embodiments (step S815). Then, it is determined whether or not an end instruction from the CPU 201 has been received (step S816), and the above-described processing of steps S801 to S815 is repeated until the end instruction is received (step S816: No loop). When an end instruction is accepted (step S816: Yes), a series of processing ends.

  As described above, in the third embodiment, the moving direction is calculated using the average value of the azimuth change amount obtained from the measurement result of the gyro sensor 112 and the geomagnetic reliability. Here, when the geomagnetic reliability is within the threshold range, it is determined that the geomagnetism is stable, and the moving direction is calculated using the measurement result of the magnetic sensor 111. Then, if the average value of the azimuth variation obtained from the measurement result of the gyro sensor 112 is smaller than the threshold value and the geomagnetic reliability is out of the threshold value range, it is determined that the geomagnetism is not stable. However, without using any sensor, the movement direction calculated last is output as it is. Further, when the average value of the azimuth change amount obtained from the measurement result of the gyro sensor 112 is larger than the threshold value and the geomagnetic reliability is out of the threshold value range, it is determined that the geomagnetism is not stable. Then, the movement direction is calculated by adding the rotation amount obtained from the measurement result of the gyro sensor 112 to the movement direction calculated last.

(Example output)
Next, an output example of the movement direction calculated by the movement direction calculation described above will be described. FIG. 9 is a chart showing an example of azimuth output of each sensor. FIG. 10 is a chart showing an output example of the geomagnetic reliability. As shown in FIG. 9, when the walking body 100 is traveling straight, the output has a small amount of change in direction (910). On the other hand, when the walking body 100 changes direction, the output has a large azimuth variable (920). Furthermore, as shown in FIG. 10, when the output of the geomagnetic reliability is referred to, a portion (1010) where the output difference of the geomagnetic reliability is large represents a situation where the geomagnetic reliability is low.

  As described above, the moving direction calculation apparatus 110 according to the present embodiment uses the measurement result of the magnetic sensor 111 itself to determine the reliability of the geomagnetism measured by the magnetic sensor 111. Therefore, unlike the prior art, it is not necessary to prepare and store a determination table for each current position of the walking body 100. In addition, since it is not necessary to make a determination in consideration of the current position as described above, neither a functional unit for specifying the current position nor a specifying process in the previous stage of the azimuth calculation is required.

  Further, by using a method of comparing the azimuth change amount by the magnetic sensor 111 accumulated for a certain time and the azimuth change amount by the gyro sensor 112, the change in the body direction due to the stepping action of the foot of the walking body 100 is removed from the measurement result. be able to. Therefore, it becomes possible to more accurately compare the azimuth change amount by the magnetic sensor 111 and the azimuth change amount by the gyro sensor 112.

  As described above, according to the present embodiment, the moving direction of the walking body can be calculated with higher accuracy without using position information.

  Further, the moving direction calculation device 110 described in the present embodiment is a PLD (hereinafter simply referred to as “ASIC”) such as a standard cell or a structured specific integrated circuit (ASIC) (hereinafter simply referred to as “ASIC”) or a PLD (such as an FPGA). It can also be realized by Programmable Logic Device). Specifically, for example, the functions 320 to 340 of the moving direction calculation device 110 described above are defined by HDL description, the HDL description is logically synthesized and given to the ASIC or PLD, and the moving direction is attached to the sensor unit 310. The calculation device 110 can be manufactured.

  The following additional notes are disclosed with respect to the embodiment described above.

(Supplementary note 1) A moving direction calculation device that is attached to a walking body and calculates the moving direction of the walking body,
An acceleration sensor for measuring acceleration accompanying the movement of the walking body;
A gyro sensor for measuring an angular velocity associated with the turning of the walking body;
A magnetic sensor for measuring geomagnetism according to the position of the walking body;
Detecting means for detecting a walking interval of the walking body from a measurement result of the acceleration sensor;
A difference calculating means for calculating a difference between an azimuth change amount obtained from the measurement result of the gyro sensor during the walking interval detected by the detection means and an azimuth change amount obtained from the measurement result of the magnetic sensor; ,
Selection means for selecting either the measurement result of the gyro sensor or the measurement result of the magnetic sensor according to the difference calculated by the difference calculation means;
Direction calculating means for calculating a moving direction of the walking body in the walking interval using the measurement result selected by the selecting means;
A moving direction calculation device comprising:

(Supplementary note 2) The moving direction calculation according to supplementary note 1, wherein the selection unit selects a measurement result of the magnetic sensor when the difference calculated by the difference calculation unit falls within a predetermined range. apparatus.

(Additional remark 3) It is provided with the reliability calculation means which calculates the reliability of the measurement result of the magnetic sensor according to the fluctuation range of the measurement result of the magnetic sensor,
The moving direction calculation apparatus according to appendix 1 or 2, wherein the selection unit selects a measurement result of the gyro sensor when the reliability calculated by the reliability calculation unit is less than a threshold value.

(Supplementary Note 4) When the reliability calculated by the reliability calculation unit is greater than or equal to a threshold value and the difference calculated by the difference calculation unit falls within a predetermined range, The moving direction calculation apparatus according to attachment 3, wherein a measurement result by the magnetic sensor is selected.

(Supplementary Note 5) A moving direction calculation device that is attached to a walking body and calculates a moving direction of the walking body,
An acceleration sensor for measuring acceleration accompanying the movement of the walking body;
A gyro sensor for measuring an angular velocity associated with the turning of the walking body;
A magnetic sensor for measuring geomagnetism according to the position of the walking body;
Reliability calculation means for calculating the reliability of the measurement result of the magnetic sensor according to the fluctuation range of the measurement result of the magnetic sensor;
Detecting means for detecting a walking interval of the walking body from a measurement result of the acceleration sensor;
A selection unit that selects the measurement result of the magnetic sensor when the reliability calculated by the reliability calculation unit is equal to or greater than a threshold; and a selection that selects the measurement result of the gyro sensor when the reliability is less than the threshold;
Direction calculating means for calculating a moving direction of the walking body in the walking interval using the measurement result selected by the selecting means;
A moving direction calculation device comprising:

(Additional remark 6) The said selection means is when the reliability calculated by the said reliability calculation means is less than a threshold value, and the difference calculated by the said difference calculation means does not fit in the predetermined range. The moving direction calculation device according to appendix 5, wherein the moving direction calculated for the previous walking interval detected by the detecting means is the moving direction of the walking body.

(Supplementary Note 7) When the measurement result of the gyro sensor is selected by the selection unit, the direction calculation unit is configured to move the gyro sensor in the movement direction calculated for the previous walking interval detected by the detection unit. The movement direction calculation device according to any one of appendices 1 to 6, wherein the movement direction of the walking body is calculated by adding the measurement results.

(Appendix 8) A moving direction calculation program for calculating a moving direction of a walking body,
A computer comprising: an acceleration sensor that measures acceleration associated with movement of the walking body; a gyro sensor that measures angular velocity associated with turning of the walking body; and a magnetic sensor that measures geomagnetism according to the position of the walking body. ,
Detecting means for detecting a walking interval of the walking body from a measurement result of the acceleration sensor;
A difference calculating means for calculating a difference between an azimuth change amount obtained from the measurement result of the gyro sensor during the walking interval detected by the detection means and an azimuth change amount obtained from the measurement result of the magnetic sensor;
Selection means for selecting one of the measurement results of the gyro sensor and the measurement result of the magnetic sensor according to the difference calculated by the difference calculation means;
Direction calculating means for calculating a moving direction of the walking body in the walking interval using the measurement result selected by the selecting means;
It is made to function as a moving direction calculation program characterized by the above-mentioned.

(Supplementary note 9)
Furthermore, it functions as a reliability calculation means for calculating the reliability of the measurement result of the magnetic sensor according to the fluctuation range of the measurement result of the magnetic sensor,
9. The moving direction calculation program according to appendix 8, wherein the selection unit selects a measurement result of the gyro sensor when the reliability calculated by the reliability calculation unit is less than a threshold value.

(Supplementary Note 10) A moving direction calculation program for calculating a moving direction of a walking body,
A computer comprising: an acceleration sensor that measures acceleration associated with movement of the walking body; a gyro sensor that measures angular velocity associated with turning of the walking body; and a magnetic sensor that measures geomagnetism according to the position of the walking body. ,
Reliability calculation means for calculating the reliability of the measurement result of the magnetic sensor according to the fluctuation range of the measurement result of the magnetic sensor;
Detecting means for detecting a walking interval of the walking body from a measurement result of the acceleration sensor;
A selection means for selecting the measurement result of the magnetic sensor when the reliability calculated by the reliability calculation means is greater than or equal to a threshold, and for selecting the measurement result of the gyro sensor when less than the threshold;
Direction calculating means for calculating a moving direction of the walking body in the walking interval using the measurement result selected by the selecting means;
It is made to function as a moving direction calculation program characterized by the above-mentioned.

It is explanatory drawing which shows the outline | summary of a moving direction calculation process. It is a block diagram which shows the hardware constitutions of a moving direction calculation apparatus. It is a block diagram which shows the functional structure of a moving direction calculation apparatus. It is a flowchart which shows the information acquisition procedure of a sensor part. 6 is a flowchart illustrating a procedure of movement direction calculation processing according to the first embodiment. It is explanatory drawing which shows the detected value for the inclination calculation of a walking body. 10 is a flowchart illustrating a procedure of movement direction calculation processing according to the second embodiment. 10 is a chart illustrating an example of threshold values in a movement direction calculation process according to the second embodiment. 12 is a flowchart illustrating a procedure of movement direction calculation processing according to the third embodiment. 10 is a chart illustrating an example of threshold values in a movement direction calculation process according to the third embodiment. It is a graph which shows the azimuth | direction output example of each sensor. It is a chart which shows the example of an output of geomagnetic reliability.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Walking body 110 Moving direction calculation apparatus 111 Magnetic sensor 112 Gyro sensor

Claims (8)

A moving direction calculation device that is attached to a walking body and calculates a moving direction of the walking body,
An acceleration sensor for measuring acceleration accompanying the movement of the walking body;
A gyro sensor for measuring an angular velocity associated with the turning of the walking body;
A magnetic sensor for measuring geomagnetism according to the position of the walking body;
Detecting means for detecting a walking interval of the walking body from a measurement result of the acceleration sensor;
A difference calculating means for calculating a difference between an azimuth change amount obtained from the measurement result of the gyro sensor during the walking interval detected by the detection means and an azimuth change amount obtained from the measurement result of the magnetic sensor; ,
Selection means for selecting either the measurement result of the gyro sensor or the measurement result of the magnetic sensor according to the difference calculated by the difference calculation means;
Direction calculating means for calculating a moving direction of the walking body in the walking interval using the measurement result selected by the selecting means;
A moving direction calculation device comprising:   The movement direction calculation apparatus according to claim 1, wherein the selection unit selects a measurement result of the magnetic sensor when the difference calculated by the difference calculation unit falls within a predetermined range. Comprising reliability calculation means for calculating the reliability of the measurement result of the magnetic sensor according to the fluctuation range of the measurement result of the magnetic sensor;
3. The moving direction calculation apparatus according to claim 1, wherein the selection unit selects a measurement result of the gyro sensor when the reliability calculated by the reliability calculation unit is less than a threshold value. 4. . A moving direction calculation device that is attached to a walking body and calculates a moving direction of the walking body,
An acceleration sensor for measuring acceleration accompanying the movement of the walking body;
A gyro sensor for measuring an angular velocity associated with the turning of the walking body;
A magnetic sensor for measuring geomagnetism according to the position of the walking body;
Reliability calculation means for calculating the reliability of the measurement result of the magnetic sensor according to the fluctuation range of the measurement result of the magnetic sensor;
Detecting means for detecting a walking interval of the walking body from a measurement result of the acceleration sensor;
A selection unit that selects the measurement result of the magnetic sensor when the reliability calculated by the reliability calculation unit is equal to or greater than a threshold; and a selection that selects the measurement result of the gyro sensor when the reliability is less than the threshold;
Direction calculating means for calculating a moving direction of the walking body in the walking interval using the measurement result selected by the selecting means;
A moving direction calculation device comprising:   The selection unit is configured to detect the detection unit when the reliability calculated by the reliability calculation unit is less than a threshold value and the difference calculated by the difference calculation unit does not fall within a predetermined range. The movement direction calculation apparatus according to claim 4, wherein the movement direction calculated for the previous walking interval detected by the step is the movement direction of the walking body.   The direction calculation means adds the measurement result of the gyro sensor to the movement direction calculated during the previous walking interval detected by the detection means when the measurement result of the gyro sensor is selected by the selection means. And the moving direction calculation apparatus as described in any one of Claims 1-5 which calculates the moving direction of the said walking body. A moving direction calculation program for calculating a moving direction of a walking body,
A computer comprising: an acceleration sensor that measures acceleration associated with movement of the walking body; a gyro sensor that measures angular velocity associated with turning of the walking body; and a magnetic sensor that measures geomagnetism according to the position of the walking body. ,
Detecting means for detecting a walking interval of the walking body from a measurement result of the acceleration sensor;
A difference calculating means for calculating a difference between an azimuth change amount obtained from the measurement result of the gyro sensor during the walking interval detected by the detection means and an azimuth change amount obtained from the measurement result of the magnetic sensor;
Selection means for selecting one of the measurement results of the gyro sensor and the measurement result of the magnetic sensor according to the difference calculated by the difference calculation means;
Direction calculating means for calculating a moving direction of the walking body in the walking interval using the measurement result selected by the selecting means;
It is made to function as a moving direction calculation program characterized by the above-mentioned. A moving direction calculation program for calculating a moving direction of a walking body,
A computer comprising: an acceleration sensor that measures acceleration associated with movement of the walking body; a gyro sensor that measures angular velocity associated with turning of the walking body; and a magnetic sensor that measures geomagnetism according to the position of the walking body. ,
Reliability calculation means for calculating the reliability of the measurement result of the magnetic sensor according to the fluctuation range of the measurement result of the magnetic sensor;
Detecting means for detecting a walking interval of the walking body from a measurement result of the acceleration sensor;
A selection means for selecting the measurement result of the magnetic sensor when the reliability calculated by the reliability calculation means is greater than or equal to a threshold, and for selecting the measurement result of the gyro sensor when less than the threshold;
Direction calculating means for calculating a moving direction of the walking body in the walking interval using the measurement result selected by the selecting means;
It is made to function as a moving direction calculation program characterized by the above-mentioned.

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