JP2012132851A - Rotation detection device, terminal apparatus, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotation detection device, a terminal apparatus, and a program that enable accurate detection of a rotating operation even when applying to a terminal apparatus carried by a user.SOLUTION: A rotation detection device is configured to: measure a cycle of walking corresponding to even-number of steps from an acceleration of a terminal apparatus carried by a user; temporally integrate an angular speed of the terminal apparatus with an interval of integration corresponding to the cycle of walking to thereby detect a difference between the present orientation representing an angle relative to a reference plane and an orientation at the time going back by a time equivalent to the cycle of walking and determine the rotation of the terminal apparatus based on the difference.

Description

  The present invention relates to a turning detection device, a terminal device, and a program for detecting, for example, that a user carrying the terminal device turns while walking.

  The GPS (Global Positioning System) is the mainstream positioning system adopted by mobile terminal devices such as mobile phones. However, if the GPS function of the mobile terminal device is continuously operated, the power consumed by the GPS function is higher than the power consumed by other functions of the mobile terminal device, so the battery driving the mobile terminal device is consumed. For example, only a relatively short continuous operation of about 8 hours can be realized.

  On the other hand, a portable terminal device that estimates a user's walking route or moving route using autonomous positioning (or autonomous navigation) has also been proposed. The result estimated using autonomous positioning is not limited to the navigation service (Navigation Service), but can be used for various services such as an information providing service corresponding to the current position of the mobile terminal device. This type of mobile terminal device includes, for example, an azimuth detection function that detects an azimuth, a step detection function that detects the number of steps, a movement distance calculation function that calculates a movement distance from a product of a step length and a step number that is input in advance, and the current absolute position It has a positioning function such as a GPS function for acquiring. This type of portable terminal device operates the GPS function intermittently so that the GPS function operates every fixed time or every fixed moving distance, and the direction, moving distance, absolute position, etc. acquired by these positioning functions Based on this, the user's travel route is estimated.

  A mobile terminal device using autonomous positioning can keep power consumption relatively low as compared with a mobile terminal device that continuously operates a GPS function to estimate a user's travel route. This is because the power consumption when the positioning function other than the GPS function is operated is smaller than the power consumption when the GPS function is operated. However, in order to improve the estimation accuracy of the user's moving route, it is necessary to acquire an accurate azimuth, moving distance, absolute position, etc. by a positioning function other than the GPS function.

  For example, when the azimuth detection function uses a magnetic sensor, it is necessary to execute calibration of the magnetic sensor. A portable terminal device having a magnetic sensor is provided with, for example, two to three magnetic sensors, and each magnetic sensor measures terrestrial magnetism and acquires an azimuth. However, even if the calibration of these magnetic sensors is executed, it is difficult to make the measurement error between the magnetic sensors, that is, the offset zero.

  In addition, since the measurement error of the positioning function other than the GPS function is accumulated and increased according to the distance that the user moves with the portable terminal device, in order to improve the estimation accuracy of the user's movement route, for example, GPS It is necessary to take measures such as correcting the error by operating the function relatively frequently. Although the absolute position acquired by the GPS function includes an error, the positioning error by the GPS function can be corrected by using a well-known walking locus interpolation technique using a spring model, for example, so that it accumulates and increases according to the moving distance of the user. The measurement error of the magnetic sensor can be corrected based on the absolute position acquired by the GPS function.

  In this way, if the GPS function is continuously operated to ensure a certain degree of position estimation accuracy, the power consumption of the mobile terminal device is relatively high, and the GPS function is intermittently operated at relatively long intervals in order to keep the power consumption low. If this is done, the position estimation accuracy decreases due to accumulated measurement errors.

  However, the GPS function cannot be used in places where satellite radio waves are difficult to reach, such as downtowns, underground malls, and buildings. For this reason, it is desired to improve the position estimation accuracy of a mobile terminal device that uses autonomous positioning even when the GPS function cannot be used, or when an accurate absolute position cannot be obtained using the GPS function.

  As an example of the direction detection function, a method for detecting a turning motion using a gyro sensor has been proposed (for example, Patent Document 1). By integrating the detection output of the gyro sensor with respect to time, the angle of the direction after turning based on the direction before detecting the turning operation is detected. If the angle is equal to or greater than a specified value, turning can be determined. However, when such a turning motion detection method using a gyro sensor is applied to a mobile terminal device carried by the user, noise is mixed into the angular velocity due to the user's walking motion. This is because when the user walks, for example, when the mobile terminal device is fixed to the waist, the hip speed is swung, and when the mobile terminal device is held in the hand, the angular velocity of the mobile terminal device is changed by the user's walking. By being greatly influenced by the operation. If noise is mixed in the angular velocity thus detected, it is difficult to accurately detect the turning motion.

Japanese Utility Model Publication No. 6-12188 JP 2008-298486 A

http://www.phoenix-c.or.jp/~hideo/reha/kouen/092aruku.html http://harp.lib.hiroshima-u.ac.jp/bitstream/harp/1509/1/ sosho30Yanagawa.pdf

  The conventional turning detection method has a problem that it is difficult to accurately detect a turning action when applied to a terminal device carried by a user.

  Accordingly, an object of the present invention is to provide a turning detection device, a terminal device, and a program capable of accurately detecting a turning operation even when applied to a terminal device carried by a user.

  According to one aspect of the present invention, a turning detection device mounted on a terminal device carried by a user, which measures a walking cycle corresponding to an even number of steps from an acceleration signal indicating the acceleration of the terminal device. And an angular velocity signal indicating the angular velocity of the terminal device in the integration interval corresponding to the walking cycle, so that the current direction indicating the angle with respect to the reference plane and the previous direction by a time corresponding to the walking cycle, A turn detection device comprising: a difference detection unit in a direction for detecting a difference between the two, and a turn determination unit that determines a turn of the terminal device based on the difference and outputs a turn detection signal indicating the determination result. Is provided.

  According to an aspect of the present invention, there is provided a terminal device carried by a user, an acceleration sensor that detects an acceleration of the terminal device and outputs an acceleration signal, and an angular velocity signal that detects an angular velocity of the terminal device. An angular velocity sensor that outputs, a walking cycle measuring unit that measures a walking cycle corresponding to an even number of steps from the acceleration signal, and time-integrating the angular velocity signal in an integration interval corresponding to the walking cycle, thereby obtaining an angle with respect to a reference plane. A difference detection unit that detects a difference between the current direction shown and a previous direction for a time corresponding to the walking cycle; and a turn detection signal that determines a turn of the terminal device based on the difference and indicates a determination result There is provided a terminal device characterized in that it includes a turning determination unit that outputs.

  According to an aspect of the present invention, there is provided a program for causing a computer mounted on a terminal device carried by a user to perform a turning detection process, wherein an acceleration signal indicating acceleration of the terminal device is input from an acceleration sensor, A walking cycle measuring procedure for measuring a walking cycle corresponding to an even number of steps based on an acceleration signal and storing it in a storage unit, an angular velocity signal indicating an angular velocity of the terminal device is input from an angular velocity sensor, and the angular velocity signal is input to the walking cycle. Detecting the difference between the current direction indicating the angle with respect to the reference plane and the previous direction by a time corresponding to the walking cycle and storing the difference in the storage unit And a turning determination procedure for determining turning of the terminal device based on the difference, outputting a turning detection signal indicating a determination result, and storing the turning detection signal in the storage unit. A program characterized by causing run data is provided.

  According to the disclosed turning detection device, the terminal device, and the program, even when applied to the terminal device carried by the user, it is possible to accurately detect the turning motion.

It is a block diagram which shows an example of the terminal device in 1st Example of this invention. It is a top view explaining direction of a terminal unit at the time of walking operation in the state where a terminal unit was equipped on a user's waist. It is a figure which shows an example of the angular velocity which a gyro sensor detects and outputs at the time of the walk of the user who carries a mobile telephone. It is a figure which shows the turning detection signal produced | generated based on the result of integrating the angular velocity shown in FIG. 3 for every 4 steps. It is a block diagram which shows an example of a structure of the computer system which can form a mobile telephone. It is a flowchart explaining the turning detection process of a mobile telephone. It is a flowchart explaining a turning detection process. It is a flowchart explaining a walk period measurement process. It is a flowchart explaining the difference detection process of direction. It is a flowchart explaining a turning determination process. It is a flowchart explaining the difference detection process of the direction in 2nd Example. It is a flowchart explaining the walk period measurement process in a 1st modification. It is a figure explaining calculation of the integration area in the walk cycle measurement process of FIG. It is a figure explaining the sample number of the angular velocity signal in the walk period measurement process of FIG. It is a figure which shows the square sum of the integral value of 3 axes | shafts calculated in 1st Example. It is a figure which shows the square sum of the integral value of 3 axes | shafts calculated in a 1st modification. It is a flowchart explaining the turning detection signal generation process in 1st Example. It is a flowchart explaining the turning detection signal generation process in a 2nd modification. It is a figure which shows the integral value of 1 axis | shaft in 1st Example. It is a figure which shows the square sum of the triaxial integral value in a 2nd modification. It is a figure explaining operation | movement of a 3rd modification.

  In the disclosed turning detection device, the terminal device, and the program, the walking cycle corresponding to the even number of steps is measured from the acceleration signal indicating the acceleration of the terminal device carried by the user, and the angular velocity signal indicating the angular velocity of the terminal device is determined according to the walking cycle. By performing time integration in the integration interval, a difference between the current direction indicating the angle with respect to the reference plane and the previous direction by a time corresponding to the walking cycle is detected, and the turning of the terminal device is determined based on this difference.

  Hereinafter, embodiments of the disclosed turning detection device, terminal device, and program will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a block diagram showing an example of a terminal device in the first embodiment of the present invention. In this example, the present invention is applied to a mobile phone, but it goes without saying that the terminal device may be a terminal device having a communication function such as a PDA (Personal Digital Assistant).

  A mobile phone 100 shown in FIG. 1 includes a turning detection device 1, a sensor group 2, and a link estimation device 3. The turning detection device 1 includes a walking cycle measurement unit 11, a direction difference detection unit 12, and a turning determination unit 13. The sensor group 2 includes a gyroscope (gyroscope) or an angular velocity sensor (hereinafter referred to as a gyro sensor) 21 that detects an angular velocity, an acceleration sensor 22, and the like.

  When the user walks, for example, when the mobile phone 100 is fixed to the waist, the hip speed is swung, and when the mobile terminal device is held in the hand, the angular velocity of the mobile phone 100 is increased by the user's walking motion. Affected. Therefore, in this example, paying attention to the feature that hip swinging and arm swinging repeat at an even number of steps, the walking cycle measuring unit 11 of the turning detection device 1 detects the acceleration detected by the acceleration sensor 22 (ie, the acceleration). The walking cycle is measured by a known method from the acceleration signal shown). The walking cycle measuring unit 11 uses a known method of the walking cycle by using the angular velocity (that is, the angular velocity signal indicating the angular velocity) detected and output by the gyro sensor 21 in addition to the acceleration detected and output by the acceleration sensor 22. You may measure with. Moreover, the difference detection unit 12 of the direction of the turning detection device 1 carries out the time integration of the angular velocity detected and output by the gyro sensor 21 in the integration interval corresponding to the walking cycle measured by the walking cycle measuring unit 11. A difference between the current direction of the telephone 100 (that is, an angle with respect to the reference plane, hereinafter also simply referred to as an angle) and a previous direction (that is, an angle) corresponding to a time corresponding to a walking cycle is detected. The turning determination unit 13 of the turning detection device 1 determines the turning angle of the mobile phone 100 or the presence / absence of the turning and the turning angle based on the angle difference detected by the direction difference detection unit 12 (that is, the determination result (that is, Turn detection signal).

  That is, in this example, paying attention to the feature that human walking is an operation in which the same movement is repeated in units of two steps, the orientation of the mobile phone 100 is detected every “walking cycle × even”, and “walking cycle × even”. By detecting the difference in the direction detected every time, noise caused by walking motion is reduced. Further, the direction of the mobile phone 100 is detected for every number of steps required for the turning operation (that is, even number of steps), and the difference in the direction detected for each “walking cycle × even number” is detected, thereby turning operation. The amount of change in the orientation of the mobile phone 100 caused by the above is calculated, and a signal for detecting the turning motion is amplified.

  FIG. 2 is a plan view for explaining the orientation of the terminal device when the user performs a walking motion with the terminal device (or mobile phone 100) worn on the waist of a human (ie, the user) as an example. is there. In this example, it is assumed that the user is moving from the left side to the right side in FIG. In the upright state ST1, the user's legs are parallel and the mobile phone 100 faces the walking direction indicated by the broken line, but in the state ST2 where the right foot is stepped on, the orientation of the mobile phone 100 turns to the left from the walking direction. Thereafter, in the state ST3 in which the left foot is stepped on, the direction of the mobile phone 100 faces right from the walking direction, and in the state ST4 in which the right foot is stepped on, the direction of the mobile phone 100 turns to the left from the walking direction. For example, when only the posture of the mobile phone 100 at the timing of stepping on the right foot is extracted from the user's walking motion, the posture of the mobile phone 100 at the timing of stepping on the right foot is the same as can be seen from the states ST2 and ST4. Similarly, when only the posture of the mobile phone 100 at the timing of stepping on the left foot is extracted, the posture of the mobile phone 100 at the timing of stepping on the left foot is the same. For this reason, it can be seen that if the difference in the orientation of the mobile phone 100 is detected every “walking cycle × even number”, for example, every two steps or every four steps, the influence of hip swing can be reduced.

  FIG. 3 is a diagram illustrating an example of an angular velocity that is detected and output by the gyro sensor 21 when a user walking with the mobile phone 100 fixed to the waist. In FIG. 3, the vertical axis indicates angular velocity in arbitrary units, and the horizontal axis indicates time in seconds (sec). As can be seen from FIG. 3, it was confirmed that the angular velocity generated by the user's hip swing appeared periodically in the detection output of the gyro sensor 21.

  Therefore, in order to reduce the angular velocity generated by hip swing, the direction difference detection unit 12 integrates the angular velocity detected and output by the gyro sensor 21 with the walking cycle measured by the walking cycle measurement unit 11. Thereby, it is possible to detect a difference from the reference of the current orientation (ie, angle) of the mobile phone 100 based on the designated orientation (ie, angle) of the mobile phone 100 before the even number of steps. That is, the direction difference detection unit 12 integrates the angular velocity with the number of steps required for the user's turning motion (that is, even number of steps), so that the mobile phone after the turn is based on the direction of the mobile phone 100 before the turn. The direction of the telephone 100 can be detected.

FIG. 4 is a diagram showing a turn detection signal generated by the turn determination unit 13 based on the result of integrating the angular velocity shown in FIG. 3 by the direction difference detection unit 12 every four steps of the user. In FIG. 4, the vertical axis indicates a turning angle based on the difference in direction (that is, angle) output by the direction difference detection unit 12, or a turning detection signal (deg ² ) indicating the turning angle and the presence / absence of turning, The horizontal axis indicates time in seconds (sec). The example of FIG. 4 shows a case where the measurement frequency is 25 Hz. As can be seen from FIG. 4, it was confirmed that noise mixed in the angular velocity of the mobile phone 100 due to hip swing was reduced and the turning detection signal was amplified. Needless to say, noise mixed into the angular velocity of the mobile phone 100 due to arm swing can be reduced by performing the same processing as described above.

  In this way, noise generated in the angular velocity of the mobile phone 100 due to the walking motion can be reduced, and the turning detection signal detected during the turning motion of the user can be amplified. Based on the turning detection signal, the turning angle of the mobile phone 100 or the presence / absence of turning and the turning angle can be accurately determined and the determination result can be output. For this reason, even if noise is mixed in the angular velocity of the mobile phone 100 due to the user's walking motion, the turning determination unit 13 reduces the noise and makes it difficult to erroneously detect the turning motion during the walking motion.

  Moreover, what is necessary is just to determine the even step set to a walk cycle according to the magnitude | size of the angle which detects turning. By setting the number of steps required for the user to make a turn in the walking cycle, that is, in the integration interval, the turn detection accuracy can be further improved.

  Returning to the description of FIG. 1, the link estimation device 3 is a well-known method for linking information related to a link combining the linear movement distances of the mobile phone 100 based on the detection result of the acceleration sensor 22 and the determination result of the turning determination unit 13. And stored in a storage unit (not shown). The link estimation device 3 can calculate the turning angle by a known method based on the turning angle of the terminal device 100 determined by the turning determination unit 13 of the turning detection device 1. Further, the link estimation device 3 stores in advance a stride information indicating the length of one step of the user input by the user from an input unit (not shown) or default stride information in the storage unit, The user's moving distance (= step length × step count) can be calculated from the stride information and the step count information calculated from the acceleration detected and output by the acceleration sensor 22. Since the method for obtaining the movement distance itself may be the same as that of a known pedometer using an acceleration sensor, a detailed description thereof will be omitted. Therefore, the link estimation apparatus 3 can determine the linear movement distance, that is, the link length, from when the user carrying the mobile phone 100 turns to change the traveling direction until the next switching of the traveling direction. A link means a line segment having a length of a moving distance. A link corresponds to a movement path and is formed by one or a plurality of nodes having a finite length. A route connecting the links is an estimated movement route of the terminal device 100.

  The mobile phone 100 has a well-known call function, and may further have various functions such as a well-known communication function such as mail and the Internet, a well-known shooting function, and a well-known GPS function. Illustration of a configuration for realizing these various functions is omitted. For example, the GPS function receives signals from a plurality of GPS satellites with an antenna, and acquires the absolute position of the mobile phone 100 (that is, the position indicated by latitude and longitude).

The turning detection device 1 or the turning detection device 1 and the link estimation device 3 shown in FIG.
For example, it can be formed by a combination of a processor such as a CPU (Central Processing Unit) and a storage unit. FIG. 5 is a block diagram showing an example of the configuration of a computer system that can form the mobile phone 100.

  In FIG. 5, a computer system (or mobile phone) 100 includes a CPU 101, a storage unit 102, a communication interface (I / F) 103 that performs wireless communication, an acceleration sensor 104, a gyro sensor 105, a geomagnetic sensor 106, and a GPS receiver 107. The input unit 201 and the display unit 202 are connected by a bus 108. In this example, the storage unit 102, the communication I / F 103, the acceleration sensor 104, the gyro sensor 105, the geomagnetic sensor 106, the GPS receiver 107, the input unit 201, and the display unit 202 are connected to the CPU 101 via the bus 108. However, the configuration may be such that each of them is directly connected to the CPU 101 without using the bus 108. When signals are directly transmitted to and received from the CPU 101 without going through the bus 108, the traffic problem on the bus 108 can be reduced.

  The acceleration sensor 104 and the gyro sensor 105 correspond to the acceleration sensor 22 and the gyro sensor 21 shown in FIG. The acceleration sensor 104 can be formed by a known sensor that detects acceleration in three axial directions, for example. The gyro sensor 105 can be formed by an angular velocity sensor that detects a relative angle with respect to a reference plane, for example. The geomagnetic sensor 106 can be formed by a known magnetic direction sensor that detects geomagnetism on a three-axis coordinate system, for example. The GPS receiver 107 has a known configuration in which, for example, signals from a plurality of GPS satellites are received by an antenna (not shown) and the absolute position of the mobile phone 100 (that is, a position indicated by latitude and longitude) is acquired. .

  The CPU 101 controls the entire computer system 100 and realizes a turning detection function, or can implement each function of the turning detection device 1 by executing various programs including a turning detection program for executing a turning detection process. . The computer system 100 may realize each function of the link estimation device 3 by realizing a link estimation function or by executing a link estimation program for executing a link estimation process. The storage unit 102 stores various data including a program executed by the CPU 101, intermediate data such as calculation processing executed by the CPU 101, a map, and the like. That is, the memory | storage part 102 can memorize | store the information which each part in the turning detection apparatus 1 or the turning detection apparatus 1 and the link estimation apparatus 3 acquired, detected, calculated, corrected, or converted. The storage unit 102 can be formed by, for example, a RAM (Random Access Memory), a ROM (Read Only Memory), an HDD (Hard Disk Drive), or the like. The input unit 201 can be formed by, for example, a numeric keypad or a keyboard. The input unit 201 is operated by a user when inputting commands and data to the computer system (that is, the mobile phone) 100. The display unit 202 displays input information from the input unit 201, a message to the user, various operation menus, a map, an estimated movement route, and the like. The input unit 201 and the display unit 202 may be integrally provided by a touch panel or the like.

  A program for causing the computer system 100 to have at least a turning detection function (turning detection program) causes the computer system 100 (that is, the CPU 101) to operate as the turning detection device 1 having a turning detection function. The program may be stored in a computer-readable storage medium. The computer-readable storage medium is limited to, for example, a semiconductor storage device such as an IC (Integrated Circuit) card memory, a magnetic disk such as a floppy (registered trademark) disk, a magneto-optical disk, and a portable recording medium such as a CD-ROM. It includes various recording media that can be accessed by the computer system 100. The computer-readable storage medium may be formed by the storage unit 102, for example.

  Needless to say, the CPU 101 further executes at least a part of various functions such as a link estimation function of the link estimation device 3, a call function, a communication function, and a photographing function by executing various programs in addition to the turning detection function. It may be realized.

  Next, turning detection processing of the computer system (ie, mobile phone) 100 will be described with reference to FIGS. The processing of FIGS. 6 to 10 is executed by the CPU 101, for example. In the following description, it is assumed that the user is carrying the mobile phone 100.

  FIG. 6 is a flowchart for explaining the turning detection process of the mobile phone 100. In FIG. 6, step S <b> 1 determines whether or not the mobile phone 100 is powered on. For example, when the user operates a power key (not shown) of the input unit 201 to turn on the mobile phone 100, the CPU 101 can detect the on state of the mobile phone 100 by a known method. If the decision result in the step S1 is YES, a step S2 performs a turning detection process which will be described later with reference to FIG. After step S2, step S3 determines whether or not the mobile phone 100 is powered off (OFF). If the determination result is NO, the process returns to step S2. On the other hand, the process ends if the decision result in the step S3 is YES.

  FIG. 7 is a flowchart for explaining the turning detection process, and shows a process executed by the turning detection apparatus 1. In FIG. 7, step S21 performs a walking cycle measurement process described later together with FIG. In step S22, direction difference detection processing described later with reference to FIG. 9 is performed. In step S23, a turning determination process described later with reference to FIG. 10 is performed.

  In the turning detection process, a turning detection signal is generated from the difference in the orientation (that is, the angle) of the mobile phone 100 based on the measured walking cycle, and if the amplitude of the turning detection signal is equal to or greater than a certain value, It is determined that it is a turning motion.

  FIG. 8 is a flowchart for explaining the walking cycle measurement process, and shows the process executed by the walking cycle measurement unit 11. In FIG. 8, step S211 inputs the triaxial acceleration (X, Y, Z) output from the acceleration sensor 106 (or 22). In step S212, the acceleration in the gravitational direction is extracted from the input acceleration (X, Y, Z). For the acceleration in the gravity direction, for example, a gravity vector is obtained using the acceleration (X, Y, Z) in a state where the user is stopped as a component of the gravity acceleration, and the absolute value of the gravity vector is extracted as an acceleration signal in the gravity direction. Can do. In step S213, high-frequency noise is reduced through a low-pass filter (LPF) for the acceleration signal in the direction of gravity. For example, as reported in Non-Patent Document 1, since the pace when a human walks in a hurry (or fast walking) is about 140 steps / minute, the cutoff frequency of the low-pass filter is, for example, 2.4 Hz. It may be set to a degree.

  In step S214, it is determined whether or not the user is walking based on the acceleration signal from which high-frequency noise has been reduced in step S213. As a method for determining whether the user is walking, for example, when the measured walking cycle is within a predetermined value, it is determined that the user is walking, and otherwise, it can be determined that the user is not walking. For example, as reported in Non-Patent Document 1, the default value in this case is about 140 steps / minute when walking with a fast pace, but 70 steps / minute when walking slowly. For example, it may be set to 0.85 sec to 0.42 sec. If the decision result in the step S214 is YES, a step S215 measures the cycle of the acceleration signal in the direction of gravity and sets it as a walking cycle, and the process ends. On the other hand, if the decision result in the step S214 is NO, a step S216 sets the walking cycle to zero (0) and the process ends.

  In order to measure the walking cycle, the magnetic flux density output from the geomagnetic sensor 106 may be used. Since the magnetic flux density of each of the three axes also periodically fluctuates due to human walking motion, the magnetic flux density of each axis is synthesized (for example, the sum of squares is obtained), and noise reduction and cycle are performed as in the case of the acceleration described above. By measuring this, it is possible to measure the walking cycle.

  Further, the angular velocity output from the gyro sensor 105 (or 21) may be used to measure the walking cycle. Similarly, the angular velocity fluctuates periodically due to human walking. Of the angular velocity values of each of the three axes, the axis that outputs the signal with the largest amplitude is extracted, and the signal of that axis is subjected to noise reduction and period measurement as in the case of the acceleration or the magnetic flux density. Thus, the walking cycle can be measured.

  Furthermore, as a method for measuring the walking cycle, it may be calculated backward from the turning detection signal. In other words, by setting a possible range as the walking cycle, defining the integration interval that matches the range as the search range, searching for the optimal integral value, and walking when the optimal integral value can be calculated Direction difference detection can also be performed with the cycle as the optimal walking cycle. For example, the search range of the walking cycle may be set to, for example, 0.37 sec to 0.63 sec, based on the pace of Japanese natural walking reported in Non-Patent Document 2. In order to obtain the integration interval from the possible range of the above-mentioned pace, the product of the pace and the number of turning steps may be obtained. For example, if the number of turning steps is 4, the integration interval is 1.48 sec to 2.52 sec. An integral value when the integral interval is 1.48 sec to 2.52 sec is calculated, an integral interval where the integral value is minimum is obtained, and a walking cycle obtained from the obtained integral interval is defined as an optimal walking cycle. it can. At this time, an integral interval in which the integral value is minimized may be obtained and defined as an optimal walking cycle.

  As described above, the walking cycle measuring function of the walking cycle measuring unit 11 can be realized by the CPU 101 using the storage unit 102 and the acceleration sensor 104, but the gyro sensor 105 or the geomagnetic sensor 106 can be used instead of the acceleration sensor 104. good. Thus, each part which implement | achieves a walk period measurement function may have a form of the module which forms one apparatus.

  FIG. 9 is a flowchart for explaining the direction difference detection process, and shows the process executed by the direction difference detection unit 12. In FIG. 9, step S221 inputs the walking cycle measured by the walking cycle measuring process of FIG. 8, and step S222 inputs the number of steps required for the user's turning motion (that is, even steps). Even if the user inputs the number of steps required for the turning operation (that is, the number of turning steps) from the input unit 201, the number of turning steps preset by default and stored in the storage unit 102 is read from the storage unit 102 and input. May be. In step S223, based on the walking cycle and the number of turning steps input in steps S221 and 222, the integration interval is calculated from “integration interval” = “walking cycle” × “turning step count”. The walking cycle may be updated in real time as in a first modification described later, or a walking cycle averaged using past values may be used. In addition, the number of turning steps is set to an even number of steps in order to reduce the periodic waveform generated in the output of the gyro sensor 105. However, if the number of steps is too large, the integration interval set in the subsequent integration process becomes large, and the integration error is increased. Which will cause errors to accumulate. The integration error occurs due to, for example, a walking cycle measurement error, an offset error, or the like. For the number of turning steps s (steps or steps) required for turning, for example, an integration error e (degree / step or deg / step) generated at each step is experimentally obtained, and the turning angle is requested. If the accuracy is a (degrees or deg), e × s <a and the remainder obtained by dividing s by 2 is 0, that is, the number of turning steps s satisfying that s is an even number is determined. Also good.

  In step S224, the angular velocity (X, Y, Z) output from the gyro sensor 105 is input. In step S225, an offset value (X, Y, Z) for correcting the offset error is input. The offset values (X, Y, Z) may be measured and used based on the angular velocity output from the gyro sensor 105 while the user is stopped, for example, or an average value of angular velocity may be used. . In step S226, the offset value (X, Y, Z) is subtracted from the angular velocity (X, Y, Z) in order to correct the offset error. In step S227, the angular velocity (X, Y, Z) of each axis with the offset error corrected is integrated in the integration interval calculated in step S223, and the process ends.

  The values input or calculated in steps S221 to S227 in FIG. 9 are stored in the storage unit 102.

  As described above, the direction difference detection function of the direction difference detection unit 12 can be realized by the CPU 101 using the storage unit 102 and the gyro sensor 105. Thus, each part which implement | achieves the difference detection function of direction may have a form of the module which forms one apparatus.

  FIG. 10 is a flowchart for explaining the turning determination process, and shows the process executed by the turning determination unit 13. In FIG. 10, step S231 indicates the turning angle, or the turning angle and the presence / absence of turning based on the difference in orientation detected by the orientation difference detection process of FIG. 9 (that is, the integrated value of the angular velocities of the respective axes). A turn detection signal is generated. The turning detection signal may be calculated, for example, by detecting the direction of gravity from the gravitational acceleration and extracting the yaw rate from the triaxial angular velocity values. Further, the turning detection signal may be calculated by combining the angular velocities of the respective axes (for example, obtaining the sum of squares).

  In step S232, a threshold value Th is input. The threshold value Th may be input from the input unit 201 by the user, or the threshold value Th set in advance by default and stored in the storage unit 102 may be read from the storage unit 102 and input. The threshold value Th may be determined according to the required accuracy of application software (or program) that uses the result of the turning detection process. For example, when the result of the turning detection process is used for the position estimation process of the mobile phone 100, the minimum angle of the corner detected from the map information around the absolute position of the mobile phone 100 may be set as the threshold Th. In step S233, it is determined whether or not the turning detection signal generated in step S231 is larger than the threshold value Th input in step S232. If the decision result in the step S233 is NO, a step S234 decides that it is a straight traveling operation and no turning operation, and the processing is ended. On the other hand, if the decision result in the step S233 is YES, it is judged that there is a turning motion, and the process is ended.

However, since an error is actually included in ω and t, the ideal value of the threshold Th is not θ ² . That is, the result of combining the integrated values is considered to include an offset Eo (reference voltage error of the gyro sensor 105, an integration error, etc.) and a signal intensity error Es (sensitivity error of the gyro sensor 105). In consideration of this, the value of the threshold Th may be corrected to θ ² × Es + Eo.

  As described above, the turning determination function of the turning determination unit 13 can be realized by the CPU 101 using the storage unit 102. Therefore, the CPU 101, the storage unit 102, the acceleration sensor 104, and the gyro sensor 105 that realize each function of the turning detection device 1 may have a module form that forms one device. The module may further include at least one of the geomagnetic sensor 106 and the GPS receiver 107 to realize the functions of the turning detection device 1 and the link estimation device 3.

(Second embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. The configuration of the mobile phone 100 in the second embodiment is the same as that shown in FIG. 1 or FIG.

  In this example, the turning motion is detected using the geomagnetic sensor 106 instead of the gyro sensor 105 (or 21). In this case, the direction difference detection process, the turning detection signal generation method and the threshold value determination method of the turning determination process are different from those in the first embodiment.

  FIG. 11 is a flowchart for explaining the direction difference detection process in the second embodiment, and shows the process executed by the direction difference detection unit 12. In FIG. 11, the same steps as those in FIG. In FIG. 11, in step S <b> 1224, the magnetic flux density (X, Y, Z) output from the geomagnetic sensor 106 is input and stored in the storage unit 102. In step S1225, the magnetic flux density (X, Y, Z) output from the geomagnetic sensor 106 before the measurement section from the present time is extracted by, for example, reading from the storage unit 102. In step S1226, the difference between the current magnetic flux density (X, Y, Z) input in step S1224 and the magnetic flux density (X, Y, Z) before the measurement section extracted in step S1225 is calculated, and the first implementation described above. It is stored in the storage unit 102 in the same manner as the integral value in the example. This difference in magnetic flux density can be handled in the same manner as the integral value in the first embodiment.

The turning determination process may be the same as in FIG. 10, but the turning detection signal generation method and threshold determination method are different from those in the first embodiment. When the turning detection signal is generated in step S231 in FIG. 10, for example, the sum of squares of the difference values calculated from the magnetic flux density (X, Y, Z) of each axis may be calculated. Further, the threshold value Th input in step S232 of FIG. 10 is calculated as T = {2H cos (θa / 2)} ^{2 where} , for example, the horizontal component force is H (μT) and the required accuracy is θa (deg). good.

(First modification)
In the first modification, the walking cycle measurement process shown in FIG. 12 is performed instead of the walking cycle measurement process shown in FIG. 8 in the first embodiment. FIG. 12 is a flowchart for explaining the walking cycle measurement process in the first modified example, and shows the process executed by the walking cycle measurement unit 11. In FIG. 12, step S1211 updates the walking cycle to the walking cycle obtained in real time by the walking cycle measurement process or updates the walking cycle obtained by averaging the walking cycles obtained in the past walking cycle measurement process. In step S1212, the same process as the direction difference detection process shown in FIG. 9 is performed. In step S1213, it is determined whether or not the integral value obtained by the difference detection process in the direction of step S1212 is the minimum Min.

  FIG. 13 is a diagram illustrating the calculation of the integration interval in the walking cycle measurement process of FIG. In FIG. 13, the vertical axis indicates the integration value, and the horizontal axis indicates the integration interval (sec). In step S1213, for example, an integration interval in which the integration value is minimum is searched for within a specified range of the integration interval as shown in FIG. In this example, the integral interval in which the integral value is minimum is 1.84 (sec). Further, every time one sample of the angular velocity signal indicating the angular velocity obtained from the gyro sensor 105 (or 21) is acquired, an integration interval in which the integral value is minimized is searched. FIG. 14 is a diagram illustrating the number of samples of angular velocity signals in the walking cycle measurement process of FIG. In FIG. 14, the vertical axis indicates the calculated integration interval (sec), and the horizontal axis indicates the number of samples of the angular velocity signal. The integration interval shown in FIG. 13 is an integration interval in which, for example, the integration value searched for as a result of obtaining the number of samples indicated by ◯ in FIG. 14 is minimum.

  If the decision result in the step S1213 is YES, a step S1214 updates the optimal walking cycle. If the determination result in step S1213 is NO, or after step S1214, step S1215 determines whether or not the calculation of the integral value of the entire walking cycle has been completed. If the determination result is NO, the process returns to step S1211. . On the other hand, the process ends if the decision result in the step S1215 is YES. If the sampling rate is increased, the change in direction can be emphasized.

FIG. 15 is a diagram illustrating a sum of squares of three-axis integral values calculated by the direction difference detection processing illustrated in FIG. 9 in the first embodiment. FIG. 16 is a diagram showing the sum of squares of three-axis integral values calculated in step 1212 of the first modification. In FIGS. 15 and 16, the vertical axis indicates the energy value (deg ² ) corresponding to the square sum of the integral values, and the horizontal axis indicates time (sec). In FIG. 15 and FIG. 16, the black solid line indicates the three-axis integral value, and the satin line indicates the turning angle, that is, the turning angle. As is clear from the comparison between FIG. 15 and FIG. 16, it was confirmed that in the case of the first modified example, the increase in energy value became clearer (that is, sharp) and the change in direction could be emphasized. .

(Second modification)
In the second modification, the turning detection signal generation process performed in step S231 of the turning determination process shown in FIG. 10 in the first embodiment is different from that in the first embodiment.

  FIG. 17 is a flowchart for explaining the turning detection signal generation processing in step S231 in the first embodiment. In FIG. 17, step S2311 inputs the integral value (X, Y, Z) of each axis calculated in the direction difference detection process, and step S2312 inputs the direction of gravity. In step S2313, a yaw component is extracted based on the integral value (X, Y, Z) and gravity direction of each axis, and in step S2314, the extracted yaw component is processed as a turning detection signal. Ends.

  FIG. 18 is a flowchart illustrating the turning detection signal generation process in step S231 in the second modification. In FIG. 18, step S2311 inputs the integral value (X, Y, Z) of each axis calculated in the direction difference detection process. Step S2351 calculates the sum of squares of the integral values (X, Y, Z) of each axis, and step S2352 uses the calculated sum of squares of the integral values (X, Y, Z) of each axis as a turning detection signal. The process ends.

FIG. 19 is a diagram showing an integral value of one axis in the first embodiment. In FIG. 19, the vertical axis represents the energy value (deg ² ) corresponding to the uniaxial integral value, the horizontal axis represents time (sec), the black solid line represents the uniaxial (yaw) integral value, and the satin line is A turning angle, that is, a turning angle is shown. FIG. 20 is a diagram showing the sum of squares of triaxial integral values in the second modification. In FIG. 20, the vertical axis represents the energy value (deg ² ) corresponding to the sum of squares of the triaxial integral value, the horizontal axis represents time (sec), the black solid line represents the triaxial integral value, and the satin line Indicates a turning angle, that is, a turning angle. As is clear from the comparison between FIG. 19 and FIG. 20, it was confirmed that the increase in the energy value became clearer (that is, sharper) in the case of the second modification, and the change in the direction could be emphasized. .

  In the above example, the walking cycle measuring unit 11 measures the walking cycle using the acceleration sensor 22, but stores in advance the standard walking time required for a human to walk for an even number of steps. It may be used as a walking cycle. In this case, it is not necessary to measure the walking cycle using the acceleration sensor 22, but it is assumed that the user is performing a standard walking motion.

  According to each of the above-described embodiments and modifications, when a user carrying the terminal device turns, noise generated by the walking action is reduced and accurate turning action can be detected. In addition, since the power of the gyro sensor or the like is less than that of, for example, a GPS receiver, accurate turning motion can be detected with relatively little power consumption. Furthermore, since the gyro sensor has fewer disturbance factors than, for example, a geomagnetic sensor, the gyro sensor can be used to accurately detect the turning motion without being affected by the disturbance factor.

The following additional notes are further disclosed with respect to the embodiment including the above examples.
(Appendix 1)
A turning detection device mounted on a terminal device carried by a user,
A walking cycle measuring unit for measuring a walking cycle corresponding to an even number of steps from an acceleration signal indicating the acceleration of the terminal device;
By integrating the angular velocity signal indicating the angular velocity of the terminal device in the integration interval corresponding to the walking cycle, the difference between the current direction indicating the angle with respect to the reference plane and the previous direction by the time corresponding to the walking cycle is obtained. A difference detection unit for detecting the direction;
A turning detection device comprising: a turning determination unit that determines turning of the terminal device based on the difference and outputs a turning detection signal indicating a determination result.
(Appendix 2)
The turning detection apparatus according to claim 1, wherein the walking cycle corresponding to the even number of steps is a value corresponding to a turning angle detected as turning by the turning determination unit.
(Appendix 3)
The turning detection device according to appendix 1 or 2, wherein the turning determination unit outputs a turning detection signal indicating the turning angle of the terminal device or the presence / absence of turning and the turning angle.
(Appendix 4)
The turning detection device according to any one of appendices 1 to 3, wherein the walking cycle measurement unit sets an integration interval in which an integration value as a result of the time integration is minimized as the walking cycle.
(Appendix 5)
The turning detection device according to any one of appendices 1 to 4, wherein the turning determination unit generates the turning detection signal from a sum of squares of integral values of three axes of the angular velocity signal.
(Appendix 6)
A terminal device carried by a user,
An acceleration sensor that detects acceleration of the terminal device and outputs an acceleration signal;
An angular velocity sensor that detects an angular velocity of the terminal device and outputs an angular velocity signal;
A walking cycle measuring unit that measures a walking cycle corresponding to an even number of steps from the acceleration signal;
The angular velocity signal is time-integrated in an integration interval corresponding to the walking cycle, thereby detecting a difference between a current direction indicating an angle with respect to a reference plane and a previous direction by a time corresponding to the walking cycle. And
A terminal device comprising: a turning determination unit that determines turning of the terminal device based on the difference and outputs a turning detection signal indicating a determination result.
(Appendix 7)
The terminal device according to appendix 6, wherein the walking cycle corresponding to the even number of steps is a value corresponding to a magnitude of a turning angle detected as turning by the turning determination unit.
(Appendix 8)
The terminal device according to appendix 6 or 7, wherein the turning determination unit outputs a turning angle of the terminal device, or a turning detection signal indicating the presence / absence of turning and a turning angle.
(Appendix 9)
The terminal device according to any one of appendices 6 to 8, wherein the walking cycle measurement unit sets, as the walking cycle, an integration interval in which an integration value as a result of the time integration is minimized.
(Appendix 10)
The terminal device according to any one of appendices 6 to 9, wherein the turning determination unit generates the turning detection signal from a sum of squares of integral values of three axes of the angular velocity signal.
(Appendix 11)
Any one of appendices 6 to 10, further comprising: a link estimation device that acquires link information related to a link that combines the linear movement distances of the terminal device based on the acceleration signal and the turning detection signal. The terminal device described in the item.
(Appendix 12)
At least one of a geomagnetic sensor or a sensor for detecting an absolute position;
The terminal device according to any one of appendices 6 to 11, further comprising a communication unit that performs wireless communication.
(Appendix 13)
A program for causing a computer mounted on a terminal device carried by a user to execute a turning detection process,
An acceleration signal indicating the acceleration of the terminal device is input from an acceleration sensor, and a walking cycle measurement procedure for measuring a walking cycle corresponding to an even number of steps based on the acceleration signal and storing it in a storage unit;
An angular velocity signal indicating the angular velocity of the terminal device is input from an angular velocity sensor, and the angular velocity signal is time-integrated in an integration interval corresponding to the walking cycle, thereby corresponding to the current direction indicating the angle with respect to the reference plane and the walking cycle. A difference detection procedure for the direction to detect the difference from the previous direction by the time to be stored and store it in the storage unit;
A program for determining turning of the terminal device based on the difference, causing the computer to execute a turning determination procedure of outputting a turning detection signal indicating a determination result and storing the turning detection signal in the storage unit.
(Appendix 14)
The program according to appendix 13, wherein the walking cycle corresponding to the even number of steps is a value corresponding to a magnitude of a turning angle detected as turning in the turning determination procedure.
(Appendix 15)
The program according to appendix 13 or 14, wherein the turning determination procedure outputs a turning detection signal indicating the turning angle of the terminal device or the presence / absence of turning and the turning angle.
(Appendix 16)
16. The program according to any one of appendices 13 to 15, wherein the walking cycle measurement procedure sets, as the walking cycle, an integration interval in which an integration value as a result of the time integration is minimized.
(Appendix 17)
The program according to any one of appendices 13 to 16, wherein the turning determination procedure generates the turning detection signal from a sum of squares of integral values of three axes of the angular velocity signal.

  As described above, the disclosed turning detection device, terminal device, and program have been described with reference to the embodiments. However, the present invention is not limited to the above embodiments, and various modifications and improvements can be made within the scope of the present invention. Needless to say.

DESCRIPTION OF SYMBOLS 1 Turning detection part 2 Sensor group 3 Link estimation apparatus 11 Walking period measurement part 12 Direction difference detection part 13 Turning determination part 100 Cellular phone (or computer system)
101 CPU
102 storage unit

Claims (5)

A turning detection device mounted on a terminal device carried by a user,
A walking cycle measuring unit for measuring a walking cycle corresponding to an even number of steps from an acceleration signal indicating the acceleration of the terminal device;
By integrating the angular velocity signal indicating the angular velocity of the terminal device in the integration interval corresponding to the walking cycle, the difference between the current direction indicating the angle with respect to the reference plane and the previous direction by the time corresponding to the walking cycle is obtained. A difference detection unit for detecting the direction;
A turning detection device comprising: a turning determination unit that determines turning of the terminal device based on the difference and outputs a turning detection signal indicating a determination result.   The turning detection device according to claim 1, wherein the walking period corresponding to the even number of steps is a value corresponding to a turning angle detected as turning by the turning determination unit.   The turning detection device according to claim 1, wherein the turning determination unit generates the turning detection signal from a sum of squares of integral values of three axes of the angular velocity signal. A terminal device carried by a user,
An acceleration sensor that detects acceleration of the terminal device and outputs an acceleration signal;
An angular velocity sensor that detects an angular velocity of the terminal device and outputs an angular velocity signal;
A walking cycle measuring unit that measures a walking cycle corresponding to an even number of steps from the acceleration signal;
The angular velocity signal is time-integrated in an integration interval corresponding to the walking cycle, thereby detecting a difference between a current direction indicating an angle with respect to a reference plane and a previous direction by a time corresponding to the walking cycle. And
A terminal device comprising: a turning determination unit that determines turning of the terminal device based on the difference and outputs a turning detection signal indicating a determination result. A program for causing a computer mounted on a terminal device carried by a user to execute a turning detection process,
An acceleration signal indicating the acceleration of the terminal device is input from an acceleration sensor, and a walking cycle measurement procedure for measuring a walking cycle corresponding to an even number of steps based on the acceleration signal and storing it in a storage unit;
An angular velocity signal indicating the angular velocity of the terminal device is input from an angular velocity sensor, and the angular velocity signal is time-integrated in an integration interval corresponding to the walking cycle, thereby corresponding to the current direction indicating the angle with respect to the reference plane and the walking cycle. A difference detection procedure for the direction to detect the difference from the previous direction by the time to be stored and store it in the storage unit;
A program for determining turning of the terminal device based on the difference, causing the computer to execute a turning determination procedure of outputting a turning detection signal indicating a determination result and storing the turning detection signal in the storage unit.