JP2018066615A - Speed measurement device, position measurement device, speed measurement method and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a speed measurement device or the like capable of exactly measuring the speed of a vehicle with a simple and inexpensive configuration.SOLUTION: A measurement value of magnitude of acceleration speed measured by an acceleration measurement part 111 of a speed measurement device 1 is made to be stored in a measurement value buffer 121, and standard deviation of the magnitude of the acceleration speed is calculated by a standard deviation calculation part 112. The standard deviation when a vehicle having the speed measurement device 1 installed thereon is made to be travelled at any constant speed is acquired in advance, a function of representing the speed and standard deviation is derived and function data 122 is kept stored in a storage part 12. When actually measured, the speed calculation part 113 calculates the speed by assigning the standard deviation calculated by the standard deviation calculation part 112 to the function representing the function data 122.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a speed measurement device that measures the speed of a vehicle, a position measurement device that measures the position of the vehicle, a speed measurement method, and a program.

  2. Description of the Related Art Conventionally, there are devices for measuring the speed of various vehicles, and the most general one is to measure the number of rotations of a wheel with a pulse meter provided on the wheel and to calculate from the number of rotations and the diameter of the wheel. In addition to these, in recent years, there have been speed measurement devices that measure the reflected waves of light and sound radiated to the outside and use the Doppler effect to determine the speed, and speed measurement devices that measure using position information such as GPS. It has been proposed (for example, Patent Documents 1 and 2).

  The measuring device described in Patent Document 1 is a device that measures the speed of a railway vehicle, irradiates an object on the rail laying side with laser light, receives scattered light from the object, extracts a Doppler signal, It is explained that the ground speed can be measured from this Doppler signal. In addition, the gait measuring device described in Patent Document 2 is a device that measures a user's moving speed using a portable terminal carried by the user, and the integrated value of acceleration exceeds a threshold value. It is explained that the speed measurement unit can calculate the moving speed of the user based on the change amount of the position information of the user and the length of the unit measurement period.

  As another method, in order to measure the speed of a moving body, a method of measuring by frequency analysis of vibration detected by an acceleration sensor has been proposed (for example, Patent Document 3). The speed detection device described in Patent Document 3 attaches an acceleration sensor to a metal part of a moving body, and detects the speed of the moving body based on a high-frequency component among vibration spectrum components of the moving body detected by the acceleration sensor. Explain that you can.

JP 2014-6161 A JP 2013-258505 A Japanese Patent No. 2856310

  Transport vehicles such as handcarts, carry carts, and forklifts that move in a relatively narrow area often do not have pulse meters on their wheels. In such a case, a conventional method of irradiating the outside with light and measuring the reflected wave, or a method of measuring based on the amount of change in position information can be considered, but a light emitting device, a light receiving device, an antenna, etc. It was necessary to install the equipment, which was a factor that increased the cost. There is also a problem that location information cannot be received in the building.

  Also, in the method of measuring speed based on the vibration spectrum detected by the acceleration sensor, there are many factors in vehicle vibration, and it is difficult to select frequency components that have a uniform correspondence with speed. There was a problem that the speed could not be measured accurately.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a speed measurement device and the like that can accurately measure the speed of a vehicle with a simple and inexpensive configuration.

In order to achieve the above object, a speed measuring device according to the first aspect of the present invention provides:
An acceleration sensor provided in the vehicle;
An acceleration acquisition unit for acquiring information of acceleration output by the acceleration sensor;
A variation amount calculation unit for calculating a variation amount of the magnitude of the acceleration acquired by the acceleration acquisition unit;
A storage unit for storing function information indicating a relationship between the variation amount calculated by the variation amount calculation unit by traveling the vehicle in advance and a speed;
A speed output unit that outputs the speed by substituting the variation amount calculated by the variation amount calculation unit at the time of actual measurement into a function indicated by the function information;
It is characterized by providing.

The acceleration acquisition unit acquires an acceleration vector from the acceleration sensor,
The magnitude of the acceleration with which the variation amount calculation unit calculates the variation amount may be a magnitude of a vertical component of the acceleration vector.

A posture acquisition unit that acquires the posture of the acceleration sensor;
A vertical direction acquisition unit that acquires a vertical direction vector with respect to the measurement axis of the acceleration sensor based on the posture acquired by the posture acquisition unit;
The variation amount calculation unit may calculate the variation amount of the magnitude of the vertical direction component of the acceleration vector using the vertical direction vector acquired by the vertical direction acquisition unit.

An angular velocity sensor provided in the vehicle;
A posture acquisition unit that acquires postures of the acceleration sensor and the angular velocity sensor;
An orientation acquired by the orientation acquisition unit; and a traveling direction acquisition unit that acquires a traveling direction vector based on the angular velocity vector output by the angular velocity sensor;
The variation amount calculation unit may calculate the variation amount of the magnitude of the traveling direction component of the acceleration vector using the traveling direction vector acquired by the traveling direction acquisition unit.

An angular velocity sensor provided in the vehicle;
An attitude calculation unit for calculating the attitude of the acceleration sensor and the angular velocity sensor;
A vertical direction calculation unit that calculates a vertical direction vector with respect to the measurement axis of the acceleration sensor, based on the posture calculated by the posture calculation unit;
An orientation calculated by the orientation calculator, and a traveling direction calculator that calculates a traveling direction vector for the measurement axis of the acceleration sensor based on the angular velocity vector output by the angular velocity sensor;
The variation amount calculation unit includes a vertical direction component variation amount of the magnitude of the vertical direction component of the acceleration vector calculated using the vertical direction vector, and a traveling direction component of the acceleration vector calculated using the traveling direction vector. You may calculate the said variation | change_quantity which is the sum of the advancing direction component variation | change_quantity of a magnitude | size.

  The variation amount may be a standard deviation.

  The variation amount may be a dispersion value.

In addition, the position measuring device according to the second aspect of the present invention includes:
The position of the vehicle provided with the speed measuring device is output by integrating the speed measured by the speed measuring device according to the first aspect.

Moreover, the speed measuring method according to the third aspect of the present invention includes:
A speed measurement method for measuring a speed of the vehicle based on an output of an acceleration sensor provided in the vehicle,
An acceleration acquisition step of acquiring acceleration information output by the acceleration sensor;
A variation amount calculating step of calculating a variation amount of the magnitude of the acceleration acquired in the acceleration acquiring step;
A storage step for storing function information indicating a relationship between the variation amount calculated in the variation amount calculation step and the speed by running the vehicle in advance;
A speed output step of outputting the speed by substituting the variation amount calculated in the variation amount calculation step at the time of actual measurement into a function indicated by the function information;
It is characterized by having.

A program according to the fourth aspect of the present invention is:
A computer connected to an acceleration sensor included in the vehicle so as to be communicable; an acceleration acquisition unit configured to acquire information on acceleration output from the acceleration sensor;
A variation amount calculation unit for calculating a variation amount of the magnitude of the acceleration acquired by the acceleration acquisition unit;
A storage unit for storing function information indicating a relationship between the variation amount calculated by the variation amount calculation unit and the speed by running the vehicle in advance;
A speed output unit that outputs the speed by substituting the variation amount calculated by the variation amount calculation unit at the time of actual measurement into a function indicated by the function information;
It is made to function as.

  According to the present invention, it is possible to accurately measure the speed of a vehicle with a simple and inexpensive configuration.

It is a figure which shows the vehicle which installed the speed measurement apparatus which concerns on Embodiment 1 of this invention. It is a block diagram which shows the hardware constitutions of the speed measuring device which concerns on Embodiment 1 of this invention. It is a block diagram which shows the function structure of a speed measuring device. It is a flowchart of a function derivation process. It is a flowchart of a speed measurement process. It is a block diagram which shows the function structure of a position measuring device. It is a block diagram which shows the function structure of the speed measuring device which concerns on Embodiment 2 of this invention. It is a flowchart of a speed measurement process. It is a block diagram which shows the hardware constitutions of the speed measurement apparatus which concerns on Embodiment 3 of this invention. It is a block diagram which shows the function structure of a speed measuring device. It is a flowchart of a speed measurement process. It is a graph which shows the relationship between speed and standard deviation.

(Embodiment 1)
Embodiment 1 of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram illustrating a vehicle in which a speed measurement device 1 according to the first embodiment is installed. In the present embodiment, a case where the speed measuring device 1 is installed in a vehicle 100 such as a forklift that travels indoors or in a narrow area as shown in FIG. 1 will be described.

  The speed measuring device 1 is composed of an arbitrary information processing apparatus in which a speed measurement processing program is installed.

  The speed measurement device 1 according to the present embodiment is an information processing device that measures a speed based on an output of an acceleration sensor. FIG. 2 is a block diagram illustrating a hardware configuration of the speed measuring device 1. As shown in FIG. 2, the speed measurement device 1 includes a control unit 11, a storage unit 12, a display unit 13, a communication unit 14, and an acceleration sensor 15. The control unit 11 is connected to the storage unit 12, the display unit 13, and the communication unit 14, and the acceleration sensor 15 is connected to the control unit 11 via the communication unit 14. Moreover, the communication part 14 can be connected with an external apparatus by arbitrary communication means. In this embodiment, the calibration apparatus 2 is connected.

  The control unit 11 includes a ROM (Read Only Memory), a RAM (Random Access Memory), and a CPU (Central Processing Unit). The ROM stores an initial program for performing various initial settings, hardware inspection, program loading, and the like. The RAM functions as a work area for temporarily storing various software programs executed by the CPU and data necessary for executing these software programs. The CPU is a central processing unit that executes various processes and operations.

  The storage unit 12 is composed of a nonvolatile memory such as a flash memory, for example. In the storage unit 12, a part of the storage area is used as a measurement value buffer 121 that overwrites and saves the measurement value of the acceleration sensor 15, and the function data 122 for calculating the speed in the other storage area, the speed measurement processing program, etc. The various programs are memorized.

  The measurement value buffer 121 is a one-dimensional buffer that stores a predetermined number of scalar values (real numbers), for example, and stores the measurement values of the acceleration sensor 15. When the number of inputs exceeds a predetermined number, the oldest data among the already stored data is overwritten and saved in order.

  The display unit 13 includes a display device such as a liquid crystal display or an organic EL (Electro Luminescence) display. The display unit 13 acquires a signal indicating the speed measurement result from the control unit 11 and outputs a number or an image on the screen of the display device.

  The communication unit 14 includes a plurality of wired or wireless communication means. The communication unit 14 acquires acceleration vector data output from the acceleration sensor 15 and outputs the data to the control unit 11. In addition, the communication unit 14 transmits the calculation result output from the control unit 11 to the calibration device 2, receives the calibration result from the calibration device 2, and outputs it to the control unit 11.

  The acceleration sensor 15 is a sensor that measures a three-dimensional acceleration vector having three measurement axes orthogonal to each other. For example, it is composed of a MEMS (Micro Electro Mechanical System) acceleration sensor. The acceleration sensor 15 outputs three components of each measurement axis direction of a three-dimensional acceleration vector, and outputs a time difference Δt between output data.

  As shown in FIG. 3, the control unit 11 of the speed measurement device 1 executes the speed measurement processing program stored in the storage unit 12, and as illustrated in FIG. 3, the acceleration measurement unit 111, the standard deviation calculation unit 112, and the speed calculation unit 113. Function as.

  The acceleration measuring unit 111 acquires three-component data in the respective measurement axis directions of the acceleration vector input from the acceleration sensor 15 via the communication unit 14, and measures the magnitude of the acceleration vector from the acquired data. Then, the acceleration measuring unit 111 stores the obtained measurement value in the measurement value buffer 121. Since a predetermined number of pieces of data are stored in the measurement value buffer 121, when the predetermined number of pieces of data are input, the oldest data among the already stored data is overwritten and saved in order. That is, the measurement value buffer 121 always stores a predetermined number or less of measurement values.

  The standard deviation calculation unit 112 reads all measurement values stored in the measurement value buffer 121 and calculates the standard deviation of the measurement values. The standard deviation calculator 112 outputs the calculated standard deviation to the communication unit 14 during calibration of the speed measurement device 1, and the communication unit 14 transmits the standard deviation to the calibration device 2.

  The standard deviation σ calculated by the standard deviation calculator 112 is expressed by the following formula (1).

  Here, the change in acceleration detected by the acceleration sensor is caused by various events. The wheel rotates smoothly by having a bearing structure in which a ball is arranged around an axle that is a rotating shaft, but vibration due to rotation of the ball constituting the bearing occurs in a high frequency band. The variation amount of the vibration changes uniformly with respect to the speed of the vehicle 100. Therefore, the speed can be expressed by a function having the standard deviation σ of acceleration as an argument. The calibration device 2 causes the vehicle to travel several times at a constant speed during calibration before actual measurement, obtains a standard deviation of the magnitude of acceleration detected by the acceleration sensor 15 at that time, and represents a relationship between the speed and the standard deviation Ask for. Then, function data 122 indicating the function is transmitted to the speed measuring device 1.

  The standard deviation calculation unit 112 outputs the calculated standard deviation to the speed calculation unit 113 when the speed measurement device 1 is actually measured. At the time of calibration before actual measurement, the communication unit 14 receives the function data 122 used for calculating the speed from the calibration device 2 and stores it in the storage unit 12. The speed calculation unit 113 calculates the speed by substituting the standard deviation input from the standard deviation calculation unit 112 into a function indicated by the function data 122 and having the standard deviation as an argument. And the speed obtained by calculation is output to the display part 13, and the display part 13 displays a speed.

  The operation of the speed measuring device 1 configured as described above will be described with reference to the flowcharts shown in FIGS. FIG. 4 is a flowchart of a function derivation process for deriving a function used in the speed measurement process. FIG. 5 is a flowchart of the speed measurement process.

  The function derivation process in FIG. 4 is a process executed by the calibration apparatus 2. The calibration device 2 causes the vehicle 100 on which the speed measuring device 1 is mounted to travel at a constant speed at a pre-adjustment stage before actual measurement, and the standard deviation data calculated and transmitted by the speed measuring device 1 at that time is used. Obtain a function that represents the relationship between speed and standard deviation.

  The speed of the vehicle 100 at the time of calibration is measured by any conventional method. Here, the vehicle 100 is traveled at a constant speed between two points whose distances have been measured in advance (step S101), and the speed is calculated from the time required to pass between the two points and the distance between the two points. (Step S102).

  When traveling between two points, the acceleration measuring unit 111 of the speed measuring device 1 acquires and acquires data of three components of each acceleration axis direction of the acceleration vector input from the acceleration sensor 15 via the communication unit 14. Measure the magnitude of the acceleration vector from the data. Then, the acceleration measuring unit 111 stores the obtained measurement value in the measurement value buffer 121.

  The standard deviation calculation unit 112 reads all measurement values stored in the measurement value buffer 121 and calculates the standard deviation of the measurement values. The calculated standard deviation is output to the communication unit 14, and the communication unit 14 transmits it to the calibration device 2.

  The calibration device 2 receives the standard deviation of the magnitude of the acceleration calculated by the standard deviation calculation unit 112 from the speed measurement device 1 (step S103). Then, the data of the speed calculated in step S102 and the standard deviation data received in step S103 are stored (step S104).

  The vehicle repeatedly runs at a constant speed at different speeds, but determines whether or not the predetermined number of measurements has been completed (step S105). If the measurement of the number of schedules has not been completed (step S105: No), returning to step S101, the process up to step S104 is repeatedly executed. When the measurement of the planned number is completed (step S105: Yes), a function representing the relationship between the speed and the standard deviation is derived, and the function data 122 including the coefficient of the function is transmitted to the speed measuring device 1 (step). S106).

  Since speed and standard deviation have a linear relationship, a linear function approximating a plot of speed and standard deviation is obtained. The method for deriving the linear function may be any conventional method, for example, using the least square method.

  The communication unit 14 of the speed measuring device 1 receives the function data 122 transmitted from the calibration device 2 and stores it in the storage unit 12.

  With the function data 122 stored in the storage unit 12, the speed measurement process shown in FIG. 5 is executed. First, the acceleration measuring unit 111 of the speed measuring device 1 acquires three-component data in each measurement axis direction of the acceleration vector input from the acceleration sensor 15 via the communication unit 14, and the magnitude of the acceleration vector from the acquired data. Measure. Then, the acceleration measurement unit 111 stores the obtained measurement value in the measurement value buffer 121 (step S201).

  The standard deviation calculator 112 reads all the measurement values stored in the measurement value buffer 121 and calculates the standard deviation of the measurement values (step S202). Next, the speed calculation unit 113 reads the function data 122, and calculates the speed by substituting the standard deviation of the magnitude of the acceleration calculated by the standard deviation calculation unit 112 into the function indicated by the function data 122 (step S203). . Then, the speed calculated in step S203 is displayed on the display unit 13 (step S204).

  In this way, the speed can be calculated and displayed based on the output of the acceleration sensor 15.

  Note that the position measuring device 3 may be configured by adding a function of calculating and outputting the position of the vehicle 100 based on the speed calculated by the speed calculating unit 113 to the speed measuring device 1. FIG. 6 is a block diagram showing a functional configuration of the position measuring device 3. As shown in FIG. 6, the position measurement device 3 further includes a position calculation unit 114 that calculates the position of the vehicle 100 by integrating the speed calculated by the speed measurement unit 113 with respect to the speed measurement device 1. The position information calculated by the position calculation unit 114 is displayed on the display unit 13.

  As described above, in the present embodiment, the measured value of the magnitude of acceleration measured by the acceleration measuring unit 111 of the velocity measuring device 1 is stored in the measured value buffer 121, and the standard deviation calculating unit 112 is measured by the magnitude of acceleration. Calculate the standard deviation of. The standard deviation when the vehicle on which the speed measuring device 1 is installed is traveled at an arbitrary constant speed is acquired in advance, a function representing the relationship between the speed and the standard deviation is derived, and the function data 122 is stored in the storage unit 12 Let me. At the time of actual measurement, the speed calculation unit 113 calculates the speed by substituting the standard deviation calculated by the standard deviation calculation unit 112 into the function indicated by the function data 122. Thereby, the speed of the vehicle can be accurately measured with a simple and inexpensive configuration in which a module including an acceleration sensor is mounted. Further, the position of the vehicle can be measured based on the measured speed.

(Embodiment 2)
Embodiment 2 of the present invention will be described in detail with reference to the drawings. Also in this embodiment, the case where the speed measuring device 1 is installed in a vehicle 100 such as a forklift that travels indoors or in a narrow area as shown in FIG. 1 will be described.

  The speed measurement apparatus 1 according to the present embodiment is an information processing apparatus that measures speed based on the output of the acceleration sensor 15 as in the first embodiment, and the hardware configuration is the same as that in the first embodiment. Since the functional configuration of the control unit 11 and the speed measurement process executed by the control unit 11 are different from those in the first embodiment, these will be described in detail with reference to FIGS.

  As illustrated in FIG. 7, the control unit 11 of the speed measurement device 1 according to the present embodiment executes a speed measurement processing program stored in the storage unit 12, so that an acceleration vector measurement unit 211 and an attitude calculation unit 212 are illustrated. , Function as vertical direction calculation unit 213, vertical direction component calculation unit 214, standard deviation calculation unit 112, and speed calculation unit 113.

  Further, the storage unit 12 of the speed measurement device 1 includes the measurement value buffer 121 as in the first embodiment, and stores the function data 122. In addition to these, the attitude of the acceleration sensor 15 input by the operator is stored. The posture setting value 123 is stored. The posture setting value 123 includes installation information for the vehicle 100, for example. Specifically, information indicating the attitude relationship between the local coordinate system of the acceleration sensor 15 and the local coordinate system of the vehicle 100 (for example, a transformation matrix (3 × 3 execution sequence) between coordinate systems is stored.

  The acceleration vector measurement unit 211 of the control unit 11 acquires the time difference Δt between the three component data in the measurement axis direction of the acceleration vector input from the acceleration sensor 15 via the communication unit 14 and the output data.

  The posture calculation unit 212 is based on the acceleration vector data input from the acceleration vector measurement unit 211 and its time difference Δt, and information on the posture relationship between the acceleration sensor 15 and the vehicle 100 included in the posture setting value 123. The attitude of the local coordinate system indicated by the measurement axis of the sensor 15 is calculated. For example, the posture calculation unit 212 outputs a rotation matrix that converts the local coordinate system indicated by the measurement axis of the acceleration sensor 15 into the world coordinate system. The dynamic calculation in the vertical direction can be performed by any conventional method. For example, Non-Patent Document 1, Masakatsu Oki, Takashi Otsuki, Takeshi Kurata, “Indoor using a self-contained sensor module for pedestrian navigation Positioning System and its Evaluation ”, Symposium“ Mobile 08 ”Proceedings, pp. 151-156, 2008.

  The vertical direction calculation unit 213 calculates the vertical direction in the coordinate system of the acceleration sensor based on the posture input from the posture calculation unit 212 and outputs a vertical direction vector. The calculation of the vertical direction is performed by, for example, converting a vertical direction vector in the world coordinate system using an inverse matrix of a rotation matrix that converts the local coordinate system of the acceleration sensor 15 input from the posture calculation unit 212 into the world coordinate system, and This is performed by calculating a vertical direction vector in the coordinate system.

  The vertical direction component calculation unit 214 calculates the vertical direction component of the acceleration vector measured by the acceleration vector measurement unit 211. Specifically, the motion obtained by subtracting the gravitational acceleration (1G≈9.8 [m / s]) from the component (scalar value) obtained by projecting the acceleration vector with respect to the vertical vector input from the vertical calculation unit 213. The acceleration component is calculated and output as the vertical component.

  The projection vector of the acceleration vector in the vertical direction can be calculated based on the following equation (2).

  Therefore, the magnitude of the projection vector is calculated by the following equation (3).

  A value obtained by subtracting 1 G of gravitational acceleration from this numerical value is a vertical component.

  The vertical direction component of the acceleration vector calculated by the vertical direction component calculation unit 214 is sequentially stored in the measurement value buffer 121. Since a predetermined number of pieces of data are stored in the measurement value buffer 121, when the predetermined number of pieces of data are input, the oldest data among the already stored data is overwritten and saved in order. That is, the measurement value buffer 121 always stores a predetermined number or less of measurement values.

  The standard deviation calculation unit 112 reads all measurement values stored in the measurement value buffer 121 and calculates the standard deviation of the measurement values. The standard deviation calculator 112 outputs the calculated standard deviation to the communication unit 14 during calibration of the speed measurement device 1, and the communication unit 14 transmits the standard deviation to the calibration device 2.

  The standard deviation σ calculated by the standard deviation calculator 112 is expressed by the following formula (4).

  The standard deviation calculation unit 112 outputs the calculated standard deviation to the speed calculation unit 113 when the speed measurement device 1 is actually measured. At the time of calibration before actual measurement, the communication unit 14 acquires the function data 122 used for calculating the speed from the calibration device 2 and stores it in the storage unit 12. The speed calculation unit 113 calculates the speed by substituting the standard deviation input from the standard deviation calculation unit 112 into a function indicated by the function data 122 and having the standard deviation as an argument. And the speed obtained by calculation is output to the display part 13, and the display part 13 displays a speed.

  The operation of the speed measuring device 1 configured as described above will be described with reference to the flowchart shown in FIG. FIG. 8 is a flowchart of the speed measurement process.

  First, as in the first embodiment, the calibration device 2 causes the vehicle 100 on which the speed measuring device 1 is mounted to travel at a constant speed at a pre-adjustment stage before actual measurement, and the speed measuring device 1 calculates at that time. The standard deviation data to be transmitted is acquired, and a function representing the relationship between the speed and the standard deviation is obtained. The function derivation process will be described with reference to FIG.

  At the time of calibration, the vehicle 100 is made to travel at a constant speed between two predetermined points (step S101), and the speed is calculated (step S102). When the vehicle 100 is made to travel, the acceleration vector measurement unit 211 of the speed measurement device 1 uses the acceleration vector input from the acceleration sensor 15 via the communication unit 14 between the three component data in each measurement axis direction and each output data. The time difference Δt is acquired.

  The posture calculation unit 212 calculates the posture of the local coordinate system indicated by the measurement axis of the acceleration sensor 15 based on the acceleration vector data input from the acceleration vector measurement unit 211, the time difference Δt, and the posture setting value 123. . The vertical direction calculation unit 213 calculates the vertical direction in the coordinate system of the acceleration sensor based on the posture input from the posture calculation unit 212.

  Thereafter, the vertical direction component calculation unit 214 calculates the vertical direction component of the acceleration vector measured by the acceleration vector measurement unit 211. The vertical direction component of the acceleration vector calculated by the vertical direction component calculation unit 214 is sequentially stored in the measurement value buffer 121. The standard deviation calculator 112 calculates the standard deviation of the measurement values stored in the measurement value buffer 121. Then, the calculated standard deviation is transmitted to the calibration device 2.

  The calibration device 2 receives the standard deviation of the vertical component of the acceleration vector calculated by the standard deviation calculation unit 112 of the speed measurement device 1 (step S103). Then, the data of the speed calculated in step S102 and the standard deviation data received in step S103 are stored (step S104).

  The vehicle repeatedly runs at a constant speed at different speeds, but determines whether or not the predetermined number of measurements has been completed (step S105). If the measurement of the number of schedules has not been completed (step S105: No), returning to step S101, the process up to step S104 is repeatedly executed. When the measurement of the planned number is completed (step S105: Yes), a function representing the relationship between the speed and the standard deviation is derived, and the function data 122 including the coefficient of the function is transmitted to the speed measuring device 1 (step). S106).

  Even in this embodiment, since the speed and the standard deviation have a linear relationship, a linear function that approximates a plot of the speed and the standard deviation is obtained. The method for deriving the linear function may be any conventional method, for example, using the least square method.

  The communication unit 14 of the speed measuring device 1 receives the function data 122 transmitted from the calibration device 2 and stores it in the storage unit 12.

  With the function data 122 stored in the storage unit 12, the speed measurement process shown in FIG. 8 is executed. First, the acceleration measuring unit 111 of the speed measuring device 1 acquires an acceleration vector input from the acceleration sensor 15 via the communication unit 14 (step S301). At this time, data of three components of the acceleration vector in each measurement axis direction and a time difference Δt between the output data are acquired.

  Based on the acquired acceleration vector data and its time difference Δt and the posture setting value 123, the vertical component of the acceleration vector is calculated and stored in the measured value buffer 121 (step S302). Specifically, as in the calibration, the posture calculation unit 212 determines the posture of the local coordinate system indicated by the measurement axis of the acceleration sensor 15 based on the acceleration vector data and its time difference Δt and the posture setting value 123. And the vertical direction calculation unit 213 calculates a vertical direction vector in the local coordinate system of the acceleration sensor based on the calculated posture.

  Thereafter, the vertical direction component calculation unit 214 calculates the vertical direction component of the acceleration vector using the vertical direction vector, and sequentially stores it in the measured value buffer 121. Then, the standard deviation calculation unit 112 calculates the standard deviation of the measurement values stored in the measurement value buffer 121 (step S303).

  Next, the speed calculation unit 113 reads the function data 122, and calculates the speed by substituting the standard deviation of the vertical component of the acceleration vector calculated by the standard deviation calculation unit 112 into the function indicated by the function data 122 (step) S304). Then, the speed calculated in step S304 is displayed on the display unit 13 (step S305).

  In this way, the speed can be calculated and displayed based on the output of the acceleration sensor 15.

  Also in this embodiment, the position measuring device 3 can be configured by adding the position calculating unit 114 to the speed measuring device 1.

  As described above, in this embodiment, the posture calculation unit 212 calculates the posture of the acceleration sensor 15 based on the acceleration vector measured by the acceleration vector measurement unit 211 of the velocity measuring device 1 and the posture setting value 123, and the Based on the posture, the vertical direction calculation unit 213 calculates the vertical direction in the coordinate system of the acceleration sensor. Then, the vertical direction component calculation unit 214 calculates the vertical direction component of the acceleration vector and stores it in the measurement value buffer 121, and the standard deviation calculation unit 112 calculates the standard deviation of the vertical direction component of the acceleration vector. The standard deviation when the vehicle on which the speed measuring device 1 is installed is traveled at an arbitrary constant speed is acquired in advance, a function representing the relationship between the speed and the standard deviation is derived, and the function data 122 is stored in the storage unit 12. Keep it. At the time of actual measurement, the speed calculation unit 113 calculates the speed by substituting the standard deviation calculated by the standard deviation calculation unit 112 into the function indicated by the function data 122. Thereby, the speed of the vehicle can be measured more accurately based on the vertical direction component of the acceleration vector.

(Embodiment 3)
Embodiment 3 of the present invention will be described in detail with reference to the drawings. Also in this embodiment, the case where the speed measuring device 1 is installed in a vehicle 100 such as a forklift that travels indoors or in a narrow area as shown in FIG. 1 will be described.

  The speed measurement device 1 according to the present embodiment is an information processing device that measures the speed based on the outputs of the acceleration sensor 15 and the angular velocity sensor 16 similar to those of the first embodiment. FIG. 9 shows a hardware configuration of the speed measurement device 1 according to the present embodiment. As shown in FIG. 9, in the velocity measuring device 1 of the present embodiment, an angular velocity sensor 16 is connected to the communication unit 14 in addition to the configuration of the first embodiment.

  The angular velocity sensor 16 is a sensor that measures a three-dimensional angular velocity vector having three measurement axes orthogonal to each other. For example, it is composed of a MEMS (Micro Electro Mechanical System) angular velocity sensor or a gyroscope. The angular velocity sensor 16 outputs three components of the three-dimensional angular velocity vector in the respective measurement axis directions and outputs a time difference Δt between the respective output data.

  Note that the acceleration sensor 15 and the angular velocity sensor 16 have the same measurement axes, or the correspondence between the measurement axes is known in advance. Further, an IMU (Inertial Measurement Unit) in which the acceleration sensor 15 and the angular velocity sensor 16 are integrated as one measurement unit may be used.

  Since the functional configuration of the control unit 31 of the present embodiment and the speed measurement processing executed by the control unit 31 are different from those of the control unit 11 of the first and second embodiments, these will be described in detail with reference to FIGS. FIG. 10 is a block diagram showing a functional configuration of the speed measuring device 1 according to the present embodiment. FIG. 11 is a flowchart of the speed measurement process.

  As shown in FIG. 10, the control unit 31 of the speed measurement device 1 according to the present embodiment executes a speed measurement processing program stored in the storage unit 12, so that an acceleration vector measurement unit 311, an angular velocity vector measurement unit are obtained. 312, posture calculation unit 313, vertical direction calculation unit 314, travel direction calculation unit 315, vertical direction component calculation unit 316, travel direction component calculation unit 317, standard deviation calculation unit (vertical direction) 318, standard deviation calculation unit (travel direction) ) 319, which functions as the speed calculation unit 113.

  Further, as shown in FIG. 10, the storage unit 12 of the speed measuring device 1 includes two buffers, a measurement value buffer (vertical direction) 124 and a measurement value buffer (traveling direction) 125, and further input by the operator. The posture setting value 123 related to the postures of the acceleration sensor 15 and the angular velocity sensor 16 and the function data 122 are stored. The posture setting value 123 includes, for example, installation information for the acceleration sensor 15 and the angular velocity sensor 16 with respect to the vehicle 100. Specifically, information indicating the posture relationship between the local coordinate system of the acceleration sensor 15 and the angular velocity sensor 16 and the local coordinate system of the vehicle 100 (for example, a transformation matrix between coordinate systems (3 × 3 execution sequence)) ) Is memorized.

  The acceleration vector measurement unit 311 of the control unit 31 acquires the time difference Δt between the three component data in the measurement axis direction of the acceleration vector input from the acceleration sensor 15 via the communication unit 14 and the output data.

  The angular velocity vector measurement unit 312 acquires the time difference Δt between the three component data in the respective measurement axis directions of the angular velocity vector input from the angular velocity sensor 16 via the communication unit 14 and each output data.

  The posture calculation unit 313 includes acceleration vector data input from the acceleration vector measurement unit 311 and its time difference Δt, angular velocity vector data input from the angular velocity vector measurement unit 312, its time difference Δt, and a posture setting value 123. The orientation of the local coordinate system indicated by the measurement axes of the acceleration sensor 15 and the angle sensor 16 is calculated based on the orientation relationship information between the acceleration sensor 15 and the angular velocity sensor 16 included in the vehicle 100 and the vehicle 100. For example, the posture calculation unit 313 calculates and outputs a rotation matrix that converts the local coordinate system indicated by the measurement axes of the acceleration sensor 15 and the angular velocity sensor 16 into the world coordinate system.

  The vertical direction calculation unit 314 calculates the vertical direction in the coordinate system of the acceleration sensor 15 based on the posture input from the posture calculation unit 313. The calculation of the vertical direction is performed by, for example, converting a vertical direction vector in the world coordinate system using an inverse matrix of a rotation matrix that converts the local coordinate system of the acceleration sensor 15 input from the attitude calculation unit 313 into the world coordinate system. This is performed by calculating a vertical direction vector in the coordinate system.

  The traveling direction calculation unit 315 calculates the traveling direction in the coordinate system of the acceleration sensor 15 based on the posture input from the posture calculation unit 313. The calculation of the traveling direction is executed by calculating the traveling direction vector in the local coordinate system based on the angular velocity vector in the world coordinate system based on the vertical direction calculated by the vertical direction calculating unit 314.

  The vertical direction component calculation unit 316 calculates the vertical direction component of the acceleration vector measured by the acceleration vector measurement unit 311. Specifically, the motion obtained by subtracting the gravitational acceleration (1G≈9.8 [m / s]) from the component (scalar value) obtained by projecting the acceleration vector with respect to the vertical vector input from the vertical calculation unit 314. The acceleration component is calculated and output as the vertical component.

  The magnitude of the projection vector in the vertical direction of the acceleration vector, that is, the vertical direction component of the acceleration vector can be calculated in the same manner as in the second embodiment.

  The vertical direction component of the acceleration vector calculated by the vertical direction component calculation unit 316 is sequentially stored in the measurement value buffer (vertical direction) 124. Since a predetermined number of pieces of data are stored in the measurement value buffer (vertical direction) 124, when the number exceeds the predetermined number, the oldest data among the already stored data is overwritten in order. Is done. That is, the measurement value buffer (vertical direction) 124 always stores a predetermined number or less of measurement values.

  The traveling direction component calculation unit 317 calculates the traveling direction component of the acceleration vector measured by the acceleration vector measurement unit 311. Specifically, a component (scalar value) obtained by projecting the acceleration vector with respect to the traveling direction vector input from the traveling direction calculation unit 315 is calculated and output as a traveling direction component.

  The traveling direction component of the acceleration vector calculated by the traveling direction component calculation unit 317 is sequentially stored in the measurement value buffer (traveling direction) 125. Since a predetermined number of pieces of data are stored in the measured value buffer (traveling direction) 125, when the number of inputs exceeds the predetermined number, the oldest data among the already stored data is overwritten and saved in order. Is done. That is, the measurement value buffer (traveling direction) 125 always stores a predetermined number or less of measurement values.

  The standard deviation calculation unit (vertical direction) 318 reads all the measurement values stored in the measurement value buffer (vertical direction) 124 and calculates the standard deviation of the measurement values. The standard deviation calculation unit (vertical direction) 318 outputs the calculated standard deviation to the communication unit 14 when the speed measurement device 1 is calibrated, and the communication unit 14 transmits the standard deviation to the calibration device 2.

  The standard deviation calculator (traveling direction) 319 reads all the measured values stored in the measured value buffer (traveling direction) 125 and calculates the standard deviation of the measured values. The standard deviation calculation unit (traveling direction) 319 outputs the calculated standard deviation to the communication unit 14 during calibration of the speed measurement device 1, and the communication unit 14 transmits the standard deviation to the calibration device 2.

  The standard deviation calculator (vertical direction) 318 and the standard deviation calculator (traveling direction) 319 calculate the standard deviation as in the second embodiment.

Here, when the standard deviation of the vertical direction component calculated by the standard deviation calculation unit (vertical direction) 318 is σ _g and the standard deviation of the direction direction component calculated by the standard deviation calculation unit (travel direction) 319 is σ _f , As a result of the measurement, the velocity v could be approximated by the following formula (5).

At the time of calibration before actual measurement, the calibration device 2 obtains a relational expression of the standard deviations σ _g , σ _f , and v based on the measurement result obtained by changing the speed. For example, the coefficients p and q of Expression (5) are obtained using a least square method or the like. Then, the calibration device 2 transmits function data 122 including the coefficients p and q to the speed measurement device 1.

FIG. 12 is a graph showing the relationship between the speed and the sum of the standard deviations σ _g and σ _f during calibration. As shown in the graph of FIG. 12, the standard deviation and the speed calculated and plotted for the six times of the constant speed can be approximated by a linear function represented by a broken line. The function data 122 related to this linear function is transmitted to the speed measuring device 1. The communication unit 14 of the speed measuring device 1 receives the function data 122 from the calibration device 2 and stores it in the storage unit 12.

When the speed measuring device 1 is actually measured, the standard deviation calculation unit (vertical direction) 318 and the standard deviation calculation unit (traveling direction) 319 output the calculated standard deviations to the speed calculation unit 113, respectively. The speed calculation unit 113 is input from the standard deviation calculation unit (vertical direction) 318 and the standard deviation calculation unit (traveling direction) 319 to the functions indicated by the function data 122 and having the standard deviations σ _g and σ _f as arguments. The speed is calculated by substituting the standard deviations σ _g and σ _f . And the speed obtained by calculation is output to the display part 13, and the display part 13 displays a speed.

  The operation of the speed measuring device 1 configured as described above will be described with reference to the flowchart shown in FIG.

  First, as in the first and second embodiments, the calibration device 2 causes the vehicle 100 on which the speed measurement device 1 is mounted to travel at a constant speed at a pre-adjustment stage before actual measurement, and the speed measurement device 1 The data of the standard deviation calculated and transmitted is acquired, and a function representing the relationship between the speed and the standard deviation is obtained. The function derivation process will be described with reference to FIG.

  At the time of calibration, the vehicle 100 is made to travel at a constant speed between two predetermined points (step S101), and the speed is calculated (step S102). When the vehicle 100 is made to travel, the acceleration vector measurement unit 311 of the speed measurement device 1 is configured such that the acceleration vector input from the acceleration sensor 15 via the communication unit 14 includes three component data in each measurement axis direction and each output data. Is obtained. Further, the angular velocity vector measuring unit 312 acquires a time difference Δt between the three component data in each measurement axis direction of the angular velocity vector input from the angular velocity sensor 16 via the communication unit 14 and each output data.

  The posture calculation unit 313 sets the acceleration vector data input from the acceleration vector measurement unit 311 and its time difference Δt, the angular velocity vector data input from the angular velocity vector measurement unit 312 and its time difference Δt, and the posture setting value 123. Based on this, the attitude of the local coordinate system indicated by the measurement axes of the acceleration sensor 15 and the angular velocity sensor 16 is calculated. The vertical direction calculation unit 314 calculates a vertical direction vector in the coordinate system of the acceleration sensor based on the posture input from the posture calculation unit 313. The traveling direction calculation unit 315 calculates a traveling direction vector in the coordinate system of the acceleration sensor based on the posture input from the posture calculation 313.

  Thereafter, the vertical direction component calculation unit 316 calculates the vertical direction component of the acceleration vector using the vertical direction vector. The vertical direction component of the acceleration vector calculated by the vertical direction component calculation unit 316 is sequentially stored in the measurement value buffer (vertical direction) 124. The standard deviation calculation unit (vertical direction) 318 calculates the standard deviation of the measurement values stored in the measurement value buffer (vertical direction) 124. Then, the calculated standard deviation is transmitted to the calibration device 2.

  On the other hand, the traveling direction component calculation unit 317 calculates the traveling direction component of the acceleration vector using the traveling direction vector. The traveling direction component of the acceleration vector calculated by the traveling direction component calculation unit 317 is sequentially stored in the measured value buffer (traveling direction) 125. The standard deviation calculator (traveling direction) 319 calculates the standard deviation of the measured values stored in the measured value buffer (traveling direction) 125. Then, the calculated standard deviation is transmitted to the calibration device 2.

  The calibration device 2 receives the standard deviation of the vertical component of the acceleration vector and the standard deviation of the traveling direction component from the velocity measuring device 1 (step S103). Then, the data of the speed calculated in step S102 and the standard deviation data received in step S103 are stored (step S104).

  The vehicle repeatedly runs at a constant speed at different speeds, but determines whether or not the predetermined number of measurements has been completed (step S105). If the measurement of the number of schedules has not been completed (step S105: No), returning to step S101, the process up to step S104 is repeatedly executed. When the measurement of the planned number is completed (step S105: Yes), a function representing the relationship between the speed and the standard deviation is derived, and the function data 122 including the coefficient of the function is transmitted to the speed measuring device 1 (step). S106).

  In the present embodiment, since the speed and the standard deviation of the vertical direction component and the sum of the standard deviation of the traveling direction component are in a linear relationship, a linear function that approximates a plot of the sum of the speed and the standard deviation is obtained. The method for deriving the linear function may be any conventional method, for example, using the least square method.

  The communication unit 14 of the speed measuring device 1 receives the function data 122 transmitted from the calibration device 2 and stores it in the storage unit 12.

  With the function data 122 stored in the storage unit 12, the speed measurement process shown in FIG. 11 is executed. First, the acceleration measurement unit 311 of the speed measurement device 1 acquires an acceleration vector input from the acceleration sensor 15 via the communication unit 14 (step S401). At this time, data of three components of the acceleration vector in each measurement axis direction and a time difference Δt between the output data are acquired.

  Based on the acquired acceleration vector data, its time difference Δt, and the posture setting value 123, the vertical component of the acceleration vector is calculated and stored in the measurement value buffer (vertical direction) 124 (step S402). Specifically, as in the calibration, the posture calculation unit 313 performs the posture of the local coordinate system indicated by the measurement axis of the acceleration sensor 15 based on the acceleration vector data, the time difference Δt, and the posture setting value 123. Based on the calculated posture, the vertical direction calculation unit 314 calculates a vertical direction vector in the coordinate system of the acceleration sensor.

  Thereafter, the vertical direction component calculation unit 316 calculates the vertical direction component of the acceleration vector using the vertical direction vector, and sequentially stores it in the measurement value buffer (vertical direction) 124.

  Next, based on the acquired acceleration vector data and its time difference, angular velocity vector data and its time difference Δt, and posture setting value 123, a traveling direction component of the acceleration vector is calculated, and a measured value buffer ( (Traveling direction) 125 (step S403). Specifically, as in the calibration, the posture calculation unit 313 uses the acceleration sensor based on the acceleration vector data and its time difference Δt, the angular velocity vector data and its time difference Δt, and the posture setting value 123. The posture of the local coordinate system indicated by the 15 measurement axes is calculated, and the traveling direction calculation unit 315 calculates a traveling direction vector in the coordinate system of the acceleration sensor based on the calculated posture.

  Thereafter, the traveling direction component calculation unit 317 calculates the traveling direction component of the acceleration vector using the traveling direction vector and sequentially stores it in the measured value buffer (traveling direction) 125.

  Then, the standard deviation calculation unit (vertical direction) 318 calculates the standard deviation of the measurement values stored in the measurement value buffer (vertical direction) 124 (step S404).

  Then, the standard deviation calculation unit (traveling direction) 319 calculates the standard deviation of the measurement values stored in the measurement value buffer (traveling direction) 125 (step S405).

  Next, the speed calculation unit 113 reads the function data 122, and adds the standard deviation of the vertical direction component of the acceleration vector calculated by the standard deviation calculation unit (vertical direction) 318 to the function indicated by the function data 122, and the standard deviation calculation unit. (Progression direction) The speed is calculated by substituting the standard deviation of the acceleration component of the acceleration vector calculated by 319 (step S406). Then, the speed calculated in step S405 is displayed on the display unit 13 (step S407).

  In this way, the speed can be calculated and displayed based on the outputs of the acceleration sensor 15 and the angular velocity sensor 16.

  Also in this embodiment, the position measuring device 3 can be configured by adding a position calculating unit to the speed measuring device 1.

  As described above, in the present embodiment, based on the acceleration vector measured by the acceleration vector measuring unit 311 of the speed measuring device 1, the angular velocity vector measured by the angular velocity vector measuring unit 312, and the posture setting value 123, The posture is calculated, and the vertical direction component and the traveling direction component of the acceleration vector are calculated based on the posture. Then, the standard deviation of the vertical component of the acceleration vector and the standard deviation of the traveling direction component of the acceleration vector are calculated. The standard deviation in the vertical direction and the traveling direction when the vehicle 100 equipped with the speed measuring device 1 is traveled at an arbitrary constant speed is acquired in advance, and a function representing the relationship between the speed and the standard deviation is derived, and the storage unit 12 Function data is stored. At the time of actual measurement, the speed calculation unit 113 calculates the speed by substituting the standard deviation in the vertical direction and the traveling direction based on the actual measurement value into the function indicated by the function data. Thereby, the speed of the vehicle can be measured more accurately based on the vertical direction component and the traveling direction component of the acceleration vector. Further, the position of the vehicle can be measured based on the measured speed.

  As described above, according to the present invention, the variation amount of the acceleration magnitude is calculated from the acceleration information output from the acceleration sensor provided in the vehicle, and the function information indicating the relationship between the variation amount and the speed is stored by driving the vehicle in advance. The speed is calculated by substituting the amount of variation in the magnitude of the acceleration into the function indicated by the function information. This makes it possible to accurately measure the vehicle speed with a simple and inexpensive configuration.

  In addition, this invention is not limited to the said embodiment, Of course, the various change in the range which does not deviate from the summary of this invention is possible.

  For example, the speed measurement device 1 calculates the speed from the magnitude of the acceleration vector or the standard deviation of the vertical component or the traveling direction component of the acceleration vector. However, instead of the standard deviation, other values and speeds indicating the amount of variation in acceleration are used. You may calculate using the function showing the relationship with. For example, a function representing the relationship between the dispersion value and the speed may be used.

  Further, although the calibration device 2 is provided separately from the speed measurement device 1 and communicates with each other, the speed measurement device 1 may be provided with a calibration function.

  In the first embodiment, the velocity is calculated based on the standard deviation of the magnitude of the acceleration vector based on the data of each measurement axis of the acceleration sensor. However, the acceleration vector is calculated based on the data of one predetermined measurement axis. The speed may be calculated based on the standard deviation of the component in the direction of the measurement axis. The speed can be measured with a simpler configuration and processing.

  In the third embodiment, the speed is calculated based on the standard deviations of the vertical direction component and the traveling direction component of the acceleration vector. However, the speed is calculated based on the standard deviation of only the traveling direction component of the acceleration vector. You may do it. The processing burden on the control unit 11 can be reduced.

  Moreover, the information terminal can be caused to function as the speed measuring device 1 or the position measuring device 3 according to the present invention by causing a program of processing executed by the control units 11 and 31 to be executed by an existing information terminal such as a computer. Is possible.

  Such a program distribution method is arbitrary, for example, a computer-readable recording medium such as a CD-ROM (Compact Disc Read-Only Memory), a DVD (Digital Versatile Disc), an MO (Magneto Optical Disc), or a memory card. It may be stored and distributed in the network, or distributed via a communication network such as the Internet.

DESCRIPTION OF SYMBOLS 1 ... Speed measuring device 2 ... Calibration apparatus 11, 31 ... Control part 12 ... Memory | storage part 13 ... Display part 14 ... Communication part 15 ... Acceleration sensor 16 ... Angular velocity sensor 100 ... Vehicle 111 ... Acceleration measuring part 112 ... Standard deviation calculation part DESCRIPTION OF SYMBOLS 113 ... Speed calculation part 114 ... Position calculation part 121 ... Measurement value buffer 122 ... Function data 123 ... Attitude setting value 124 ... Measurement value buffer (vertical direction)
125 ... Measurement value buffer (traveling direction)
DESCRIPTION OF SYMBOLS 211 ... Acceleration vector measurement part 212 ... Attitude calculation part 213 ... Vertical direction calculation part 214 ... Vertical direction component calculation part 311 ... Acceleration vector measurement part 312 ... Angular velocity vector measurement part 313 ... Attitude calculation part 314 ... Vertical direction calculation part 315 ... Progression Direction calculation unit 316 ... Vertical direction component calculation unit 317 ... Travel direction component calculation unit 318 ... Standard deviation calculation unit (vertical direction)
319 ... Standard deviation calculator (traveling direction)

Claims (10)

An acceleration sensor provided in the vehicle;
An acceleration acquisition unit for acquiring information of acceleration output by the acceleration sensor;
A variation amount calculation unit for calculating a variation amount of the magnitude of the acceleration acquired by the acceleration acquisition unit;
A storage unit for storing function information indicating a relationship between the variation amount calculated by the variation amount calculation unit by traveling the vehicle in advance and a speed;
A speed output unit that outputs the speed by substituting the variation amount calculated by the variation amount calculation unit at the time of actual measurement into a function indicated by the function information;
A speed measuring device comprising: The acceleration acquisition unit acquires an acceleration vector from the acceleration sensor,
The magnitude of the acceleration with which the variation amount calculation unit calculates the variation amount is a magnitude of a vertical direction component of the acceleration vector.
The speed measuring device according to claim 1. An attitude calculation unit for calculating the attitude of the acceleration sensor;
A vertical direction calculation unit that calculates a vertical direction vector with respect to the measurement axis of the acceleration sensor based on the posture calculated by the posture calculation unit;
The variation amount calculation unit calculates the variation amount of the magnitude of the vertical direction component of the acceleration vector using the vertical direction vector calculated by the vertical direction calculation unit.
The speed measuring device according to claim 2. An angular velocity sensor provided in the vehicle;
An attitude calculation unit for calculating the attitude of the acceleration sensor and the angular velocity sensor;
A posture calculated by the posture calculator, and a traveling direction calculator that calculates a traveling direction vector based on the angular velocity vector output by the angular velocity sensor;
The variation amount calculation unit calculates the variation amount of the magnitude of the traveling direction component of the acceleration vector using the traveling direction vector calculated by the traveling direction calculation unit.
The speed measuring device according to claim 1. An angular velocity sensor provided in the vehicle;
An attitude calculation unit for calculating the attitude of the acceleration sensor and the angular velocity sensor;
A vertical direction calculation unit that calculates a vertical direction vector with respect to the measurement axis of the acceleration sensor, based on the posture calculated by the posture calculation unit;
An orientation calculated by the orientation calculator, and a traveling direction calculator that calculates a traveling direction vector for the measurement axis of the acceleration sensor based on the angular velocity vector output by the angular velocity sensor;
The variation amount calculation unit includes a vertical direction component variation amount of the magnitude of the vertical direction component of the acceleration vector calculated using the vertical direction vector, and a traveling direction component of the acceleration vector calculated using the traveling direction vector. Calculating the amount of variation, which is the sum of the amount of variation in the traveling direction component of the size,
The speed measuring device according to claim 1. The variation amount is a standard deviation.
The speed measuring device according to any one of claims 1 to 5. The variation amount is a variance value.
The speed measuring device according to any one of claims 1 to 5. The position of the vehicle provided with the speed measurement device is output by integrating the speed measured by the speed measurement device according to any one of claims 1 to 7.
Position measuring device. A speed measurement method for measuring a speed of the vehicle based on an output of an acceleration sensor provided in the vehicle,
An acceleration acquisition step of acquiring acceleration information output by the acceleration sensor;
A variation amount calculating step of calculating a variation amount of the magnitude of the acceleration acquired in the acceleration acquiring step;
A storage step for storing function information indicating a relationship between the variation amount calculated in the variation amount calculation step and the speed by running the vehicle in advance;
A speed output step of outputting the speed by substituting the variation amount calculated in the variation amount calculation step at the time of actual measurement into a function indicated by the function information;
A speed measuring method. A computer connected to an acceleration sensor included in the vehicle so as to be communicable; an acceleration acquisition unit configured to acquire information on acceleration output from the acceleration sensor;
A variation amount calculation unit for calculating a variation amount of the magnitude of the acceleration acquired by the acceleration acquisition unit;
A storage unit for storing function information indicating a relationship between the variation amount calculated by the variation amount calculation unit and the speed by running the vehicle in advance;
A speed output unit that outputs the speed by substituting the variation amount calculated by the variation amount calculation unit at the time of actual measurement into a function indicated by the function information;
Program to function as.

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