Inertial sensor device

Abstract

To provide an inertial sensor device that can improve calculation accuracy while suppressing increases in calculation processing time and communication time. [Solution] An inertial sensor device in which a first inertial measurement unit transmits a first signal output from a signal processing unit to a third inertial measurement unit, a second inertial measurement unit transmits a second signal output from a signal processing unit to the third inertial measurement unit, the third inertial measurement unit transmits a fourth signal output by the signal processing unit after performing calculations on the first signal, the second signal, and a third signal which is the output signal of its own inertial sensor to a fourth inertial measurement unit, and the fourth inertial measurement unit transmits a sixth signal output by the signal processing unit after performing calculations on the fourth signal and a fifth signal which is the output signal of its own inertial sensor to an external device.

Description

Technical Field

[0001] The present invention relates to an inertial sensor device.

Background Art

[0002] Patent Document 1 describes an inertial measurement system in which N inertial measurement devices including a three-axis angular velocity sensor and a three-axis acceleration sensor are connected in series to a host device, and one inertial measurement device averages the data sampled by each of the N inertial measurement devices and transmits it to the host device. According to the inertial measurement system described in Patent Document 1, since one inertial measurement device averages the data sampled by each of the N inertial measurement devices, the noise component is reduced to 1 / √N and the load on the host device is reduced.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the inertial measurement system described in Patent Document 1, since N inertial measurement devices are connected in series to the host device, the processing time and communication time increase in proportion to the number N of inertial measurement devices. Also, when one inertial measurement device fails, all the inertial measurement devices connected ahead of that inertial measurement device become unusable, and the noise reduction effect is significantly reduced.

Means for Solving the Problems

[0005] One aspect of the inertial sensor device according to the present invention is an inertial sensor device having a plurality of inertial measurement units and connected to an external device, where each of the plurality of inertial measurement units Inertial sensor and, A signal processing unit that processes the output signal of the inertial sensor, The First Communications Department and, It is equipped with a second communications unit, The plurality of inertial measurement units include a first inertial measurement unit, a second inertial measurement unit, a third inertial measurement unit, and a fourth inertial measurement unit. The first communication unit of the first inertial measurement unit and the first communication unit of the second inertial measurement unit are connected to the second communication unit of the third inertial measurement unit. The first communication unit of the third inertial measurement unit is connected to the second communication unit of the fourth inertial measurement unit. The first communication unit of the fourth inertial measurement unit is connected to the external device, The first communication unit of the first inertial measurement unit transmits the first signal output from the signal processing unit of the first inertial measurement unit to the second communication unit of the third inertial measurement unit. The first communication unit of the second inertial measurement unit transmits the second signal output from the signal processing unit of the second inertial measurement unit to the second communication unit of the third inertial measurement unit. The signal processing unit of the third inertial measurement unit performs calculations on the first signal, the second signal, and the third signal which is the output signal of the inertial sensor of the third inertial measurement unit, and outputs a fourth signal. The first communication unit of the third inertial measurement unit transmits the fourth signal to the second communication unit of the fourth inertial measurement unit. The signal processing unit of the fourth inertial measurement unit performs calculations on the fourth signal and the fifth signal, which is the output signal of the inertial sensor of the fourth inertial measurement unit, and outputs a sixth signal. The first communication unit of the fourth inertial measurement unit transmits the sixth signal to the external device.

[0006] Another aspect of the inertial sensor device according to the present invention is: An inertial sensor device having multiple inertial measurement units and connected to an external device, Each of the aforementioned plurality of inertial measurement units is Inertial sensor and, A signal processing unit that processes the output signal of the inertial sensor, The First Communications Department and, It is equipped with a second communications unit, The plurality of inertial measurement units include a first inertial measurement unit, a second inertial measurement unit, and a third inertial measurement unit. The first communication unit of the first inertial measurement unit and the first communication unit of the second inertial measurement unit are connected to the second communication unit of the third inertial measurement unit. The first communication unit of the third inertial measurement unit is connected to the external device, The first communication unit of the first inertial measurement unit transmits the first signal output from the signal processing unit of the first inertial measurement unit to the second communication unit of the third inertial measurement unit. The first communication unit of the second inertial measurement unit transmits the second signal output from the signal processing unit of the second inertial measurement unit to the second communication unit of the third inertial measurement unit. The signal processing unit of the third inertial measurement unit performs calculations on the first signal, the second signal, and the third signal which is the output signal of the inertial sensor of the third inertial measurement unit, and outputs a fourth signal. The first communication unit of the third inertial measurement unit transmits the fourth signal to the external device. [Brief explanation of the drawing]

[0007] [Figure 1] A diagram showing the overall configuration of the inertial sensor device according to the first embodiment. [Figure 2] A diagram showing an example configuration of the inertial measurement unit in the first embodiment. [Figure 3] A flowchart illustrating an example of the initial setup procedure for the inertial measurement unit in the first embodiment. [Figure 4] A diagram showing the overall configuration of the inertial sensor device according to the second embodiment. [Figure 5]A flowchart showing an example of the procedure for initial setting of the inertial measurement unit in the second embodiment. [Figure 6] A diagram showing a configuration example of the inertial measurement unit in the third embodiment.

Embodiments for Carrying Out the Invention

[0008] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. Note that the embodiments described below do not unduly limit the content of the present invention described in the claims. Also, not all of the configurations described below are essential constituent elements of the present invention.

[0009] 1. First Embodiment 1-1. Configuration of the Inertial Sensor Device FIG. 1 is a diagram showing the overall configuration of the inertial sensor device according to the first embodiment. As shown in FIG. 1, the inertial sensor device 1 according to the first embodiment has three inertial measurement units (IMUs) 2a, 2b, and 2c, and is connected to a host device 3 which is an external device.

[0010] Each of the IMUs 2a, 2b, and 2c has an inertial sensor, and performs predetermined signal processing on the data output from the inertial sensor to generate measurement data. The inertial sensors included in each of the IMUs 2a, 2b, and 2c detect the same type of physical quantity with respect to each other. For example, each inertial sensor may detect acceleration of one axis or two or more axes, angular velocity of one axis or two or more axes, or three-axis acceleration and three-axis angular velocity. Hereinafter, it will be described on the assumption that each inertial sensor measures three-axis acceleration and three-axis angular velocity.

[0011] IMU 2a is connected to the host device 3 and can communicate with the host device 3. In the communication between the IMU 2a and the host device 3, the host device 3 serves as the master and the IMU is the slave. That is, the host device 3 transmits various commands to the IMU 2a, and the IMU 2a performs processing according to the received commands.

[0012] ​ Furthermore, IMU2a is connected to two IMU2b and 2c units, and can communicate with each of them. In communication between IMU2a and each of IMU2b and 2c, IMU2a acts as the master, and IMU2b and 2c act as slaves. That is, IMU2a sends various commands to IMU2b and 2c, and IMU2b and 2c each perform processing according to the received commands.

[0013] Thus, IMU2a functions as a "master unit" capable of communicating with host device 3, while the other IMUs, IMU2b and IMU2c, function as "slave units." In the following, IMU2b and IMU2c will be referred to as "slave unit 1" and "slave unit 2," respectively.

[0014] When IMU2a receives a sampling start command from the host device 3 requesting the transmission of measurement data, it samples the data detected by its own inertial sensor and performs predetermined signal processing, and also sends a sampling start command to IMU2b and 2c respectively. When IMU2b and 2c each receive a sampling start command from IMU2a, they sample the data detected by their own inertial sensor, perform predetermined signal processing, and transmit the data obtained from the signal processing to IMU2a. IMU2a acquires the data from IMU2b and 2c respectively and performs a synthesis process on the acquired data and the data obtained from its own predetermined signal processing. The synthesis process may be, for example, an averaging process. IMU2a then transmits the measurement data obtained from the synthesis process to the host device 3. The measurement data obtained from the synthesis process includes measured values ​​of the three-axis acceleration of the mutually orthogonal X, Y, and Z axes, and measured values ​​of the three-axis angular velocity of the X, Y, and Z axes.

[0015] IMU2a outputs a clock signal CLK generated by its built-in oscillator circuit to IMU2b and 2c. Each of IMU2a, 2b, and 2c performs signal processing in synchronization with the clock signal CLK. Therefore, by sampling the output signals of the inertial sensors at the same edge of the clock signal CLK, IMU2a can synthesize the three data points measured simultaneously by each of IMU2a, 2b, and 2c.

[0016] 1-2. Configuration of the Inertial Measurement Unit (IMU) Figure 2 shows example configurations of IMU2a, 2b, and 2c. In the example in Figure 2, IMU2a, 2b, and 2c have the same configuration, and similar components in IMU2a, 2b, and 2c are denoted by the same symbols. However, IMU2a, 2b, and 2c do not necessarily have the same configuration. Below, the configuration of IMU2a will be described in detail, and the configurations of IMU2b and 2c will mainly be described as differing from those of IMU2a.

[0017] As shown in Figure 2, each of the IMUs 2a, 2b, and 2c includes an inertial sensor 10, a signal processing unit 20, communication interface circuits 31 and 32, a control unit 40, a memory unit 50, an oscillator circuit 60, and a switch 70.

[0018] The memory unit 50 includes a register 51 and a non-volatile memory 52. ​​The memory unit 50 may also include RAM instead of the register 51, or it may include RAM together with the register 51. RAM is an abbreviation for Random Access Memory.

[0019] The oscillator circuit 60 of the IMU2a performs an oscillation operation and outputs an oscillation signal. For example, the oscillator circuit 60 may be a crystal oscillator that vibrates a crystal resonator to output an oscillation signal. Since crystal resonators have a high Q value and good temperature characteristics, by using a crystal oscillator circuit for the oscillator circuit 60, an oscillation signal with a small frequency deviation can be obtained. To further reduce the frequency deviation of the oscillation signal, the oscillator circuit 60 may be a temperature-compensated crystal oscillator.

[0020] The oscillation signal output from the oscillation circuit 60 is output as a clock signal CLK to IMUs 2b and 2c via the ON switch 70. This clock signal CLK is also supplied to each part of IMU 2a, and each part of IMU 2a operates in synchronization with the clock signal CLK. On the other hand, in IMUs 2b and 2c, the oscillation circuit 60 is set to stop operating, and the switch 70 is set to the OFF state. Then, each part of IMUs 2b and 2c operates in synchronization with the clock signal CLK supplied from IMU 2a. The on / off operation of the oscillation circuits 60 and the on / off operation of the switch 70 in each of IMUs 2a, 2b, and 2c are controlled by the setting values ​​of the registers 51 in the respective memory units 50 of IMUs 2a, 2b, and 2c.

[0021] The inertial sensor 10 is, for example, a 6DoF sensor that detects 3-axis acceleration and 3-axis angular velocity. DoF is an abbreviation for Degrees of freedom. Specifically, the inertial sensor 10 detects 3-axis acceleration of the x, y, and z axes, and 3-axis angular velocity of the x, y, and z axes. The inertial sensor 10 has a temperature sensor (not shown) and outputs sensor data SD including the detected values ​​of 3-axis acceleration, 3-axis angular velocity, and temperature. The sensor data SD is input to the signal processing unit 20. The temperature sensor may be provided outside the inertial sensor 10, in which case the sensor data SD, which is a combination of the data output from the inertial sensor 10 and the temperature data detected by the temperature sensor, may be input to the signal processing unit 20.

[0022] The signal processing unit 20 processes the sensor data SD, which is the output signal of the inertial sensor 10. As shown in Figure 2, the signal processing unit 20 includes a correction processing unit 21, a matching processing unit 22, and a synthesis processing unit 23.

[0023] The correction processing unit 21 performs correction processing on the sensor data SD and outputs the corrected data CPD. The correction processing includes, for example, bias correction, sensitivity correction, linearity correction, and temperature correction. The correction processing may also include orthogonality correction processing, which converts the 3-axis acceleration and 3-axis angular velocity of the x, y, and z axes detected by the inertial sensor 10 into 3-axis acceleration and 3-axis angular velocity of the mutually orthogonal x', y', and z' axes. Note that orthogonality correction may be performed internally by the inertial sensor 10. Various correction information used in the correction processing is created in advance and stored in the non-volatile memory 52 of the storage unit 50. The corrected data CPD is input to the matching processing unit 22.

[0024] The alignment processing unit 22 performs alignment processing on the corrected data CPD for the detection axes of the inertial sensor 10 and outputs the aligned data ALD. Specifically, the alignment processing is the process of converting the 3-axis acceleration values ​​and 3-axis angular velocity values ​​of the x', y', and z' axes included in the corrected data CPD into 3-axis acceleration values ​​of the X, Y, and Z axes, and 3-axis angular velocity values ​​of the X, Y, and Z axes of the inertial sensor device 1. The alignment information used in the alignment processing is created in advance and stored in the non-volatile memory 52 of the storage unit 50. This alignment information, for example, converts the 3 axes x', y', and z' axes, which are mutually orthogonal, into mutually orthogonal axes set in the inertial sensor device 1. This could be a rotation matrix that transforms the data into three axes: the X, Y, and Z axes. The matched ALD data is input to the synthesis processing unit 23.

[0025] The synthesis processing unit 23 performs a synthesis process on the matched data ALD and the matched data ALD2 and ALD3 obtained from IMU2b and 2c, respectively, via the communication interface circuit 32, and outputs the synthesized data, which is the measurement data DO. The synthesis process may be, for example, an averaging process. Specifically, the synthesis processing unit 23 calculates the average value of the X, Y, and Z axis accelerations by adding the X, Y, and Z axis acceleration values ​​contained in the matched data ALD, the X, Y, and Z axis acceleration values ​​contained in the matched data ALD2, and the X, Y, and Z axis acceleration values ​​contained in the matched data ALD3, and dividing by 3. Similarly, the synthesis processing unit 23 calculates the average value of the X, Y, and Z axis angular velocities by adding the angular velocity values ​​of the X, Y, and Z axes contained in the matched data ALD, the angular velocity values ​​of the X, Y, and Z axes contained in the matched data ALD2, and the angular velocity values ​​of the X, Y, and Z axes contained in the matched data ALD3, and dividing by 3. Alternatively, the synthesis processing unit 23 may calculate the average value of the temperature by adding the temperature value contained in the matched data ALD, the temperature value contained in the matched data ALD2, and the temperature value contained in the matched data ALD3, and dividing by 3.

[0026] Since the communication interface circuits 32 of IMU2b and 2c are not connected to the IMU, the matching data ALD2 and ALD3 are not input to the respective synthesis processing units 23 of IMU2b and 2c. Therefore, the respective synthesis processing units 23 of IMU2b and 2c output the matching data ALD as the measurement data DO.

[0027] The communication interface circuit 31 of IMU2a is connected to the host device 3 and is a circuit for the control unit 40 of IMU2a to communicate with the host device 3. It receives various commands sent from the host device 3 and outputs them to the control unit 40. The communication interface circuit 31 of IMU2b is connected to the communication interface circuit 32 of IMU2a and is a circuit for the control unit 40 of IMU2b to communicate with the control unit 40 of IMU2a. It receives various commands sent from IMU2a and outputs them to the control unit 40. The communication interface circuit 31 of IMU2c is connected to the communication interface circuit 32 of IMU2a and is a circuit for the control unit 40 of IMU2c to communicate with the control unit 40 of IMU2a. It receives various commands sent from IMU2a and outputs them to the control unit 40. The communication standard used via the communication interface circuits 31 of IMU2a, 2b, and 2c may be, for example, UART, SPI, or other standards.

[0028] The control units 40 of IMUs 2a, 2b, and 2c interpret the commands received by the communication interface circuit 31 and perform processing according to those commands. For example, if the received command is a write command to register 51 or non-volatile memory 52, the control unit 40 writes the data contained in the command to register 51 or non-volatile memory 52. ​​If the received command is a read command to register 51 or non-volatile memory 52, the control unit 40 reads the data stored in register 51 or non-volatile memory 52 and transmits the read data via the communication interface circuit 31. If the received command is a command requesting the transmission of measurement data DO, the control unit 40 transmits the measurement data DO output from the signal processing unit 20 via the communication interface circuit 31.

[0029] The communication interface circuit 32 of IMU2a is connected to the respective communication interface circuits 31 of IMU2b and 2c, and is a circuit for the control unit 40 of IMU2a to communicate with the respective control units 40 of IMU2b and 2c. The communication standard used via the communication interface circuit 32 of IMU2a may be, for example, UART or SPI. Or, other standards may also be used. The control unit 40 of IMU2a generates various commands for IMU2b and 2c, and transmits the generated commands to the respective communication interface circuits 31 of IMU2b and 2c via the communication interface circuit 32.

[0030] For example, when the control unit 40 of IMU2a receives a command from the host device 3 via the communication interface circuit 31 requesting the transmission of measurement data DO, it sends a command via the communication interface circuit 32 to the respective communication interface circuits 31 of IMU2b and 2c requesting the transmission of measurement data DO.

[0031] In each of the IMUs 2b and 2c, the control unit 40 receives the command via the communication interface circuit 31. Then, in IMU 2b, under the control of the control unit 40, the communication interface circuit 31 transmits the measurement data DO output from the signal processing unit 20 to the communication interface circuit 32 of IMU 2a. Similarly, in IMU 2c, under the control of the control unit 40, the communication interface circuit 31 transmits the measurement data DO output from the signal processing unit 20 of IMU 2c to the communication interface circuit 32 of IMU 2a.

[0032] Subsequently, in IMU2a, the control unit 40 receives measurement data DO from IMU2b via the communication interface circuit 32 and outputs the received measurement data DO as matched data ALD2 to the synthesis processing unit 23 of the signal processing unit 20. Similarly, the control unit 40 receives measurement data DO from IMU2c via the communication interface circuit 32 and outputs the received measurement data DO as matched data ALD3 to the synthesis processing unit 23 of the signal processing unit 20. Then, in IMU2a, the signal processing unit 20 performs calculations on the matched data ALD2, ALD3 and sensor data SD, which is the output signal of the inertial sensor 10, and outputs measurement data DO. That is, the signal processing unit 20 generates matched data ALD based on sensor data SD using the correction processing unit 21 and the matching processing unit 22, and outputs measurement data DO by performing averaging processing on the matched data ALD, ALD2, and ALD3 using the synthesis processing unit 23. Then, the communication interface circuit 31 of IMU2a transmits the measurement data DO output from the signal processing unit 20 to the host device 3.

[0033] Furthermore, for example, if the control unit 40 of IMU2a receives a write command for register 51 or non-volatile memory 52 of IMU2b from the host device 3 via the communication interface circuit 31, it transmits the command to the communication interface circuit 31 of IMU2b via the communication interface circuit 32. In IMU2b, the control unit 40 receives the command via the communication interface circuit 31 and writes the data contained in the command to register 51 or non-volatile memory 52. ​​The processing of IMU2a and IMU2c is similar when the control unit 40 of IMU2a receives a write command for register 51 or non-volatile memory 52 of IMU2c from the host device 3 via the communication interface circuit 31.

[0034] Furthermore, when the control unit 40 of IMU2a receives a read command for the register 51 or non-volatile memory 52 of IMU2b from the host device 3 via the communication interface circuit 31, it transmits the command to the communication interface circuit 31 of IMU2b via the communication interface circuit 32. In IMU2b, the control unit 40 receives the command via the communication interface circuit 31, reads the data stored in the register 51 or non-volatile memory 52, and transmits the read data to the communication interface circuit 32 of IMU2a via the communication interface circuit 31. Subsequently, in IMU2a, the control unit 40 receives the data stored in the register 51 or non-volatile memory 52 of IMU2b via the communication interface circuit 32, and transmits the received data to the host device 3 via the communication interface circuit 31. The same applies to the processing of IMU2a and IMU2c when the control unit 40 of IMU2b receives a read command for the register 51 or non-volatile memory 52 of IMU2c from the host device 3 via the communication interface circuit 31.

[0035] Furthermore, each of the IMUs 2a, 2b, and 2c may function as a correction processing unit 21, an alignment processing unit 22, a synthesis processing unit 23, and a control unit 40, respectively, when a processing unit such as a CPU or microcontroller unit (not shown) executes a program stored in the non-volatile memory 52.

[0036] 1-3. Initial setup of the inertial sensor device When the inertial sensor device 1 receives a multi-device connection mode command from the host device 3, it performs the initial setup of IMUs 2a, 2b, and 2c. Figure 3 is a flowchart showing an example of the procedure for initial setup of IMUs 2a, 2b, and 2c in the first embodiment.

[0037] As shown in Figure 3, in step S1, when IMU2a receives an initial setup command, the multiple device connection mode command, from the host device 3, in step S2, IMU2a first sets the master device ID for itself and sends initial setup commands to slave device 1 and slave device 2.

[0038] The control unit 40 of IMU2a recognizes itself as the master unit upon receiving a multi-unit connection mode command from the host device 3, and sets the master unit's ID=0 in register 51 as its own ID. Also, because it is the master unit, the control unit 40 of IMU2a assumes that slave units 1 and 2 are connected to the communication interface circuit 32, and sends an initial setup command including the ID of slave unit 1 to slave unit 1, and an initial setup command including the ID of slave unit 2 to slave unit 2. The ID of slave unit 1 is 1, and the ID of slave unit 2 is 2. That is, with respect to the master unit's ID=0, the relationship is that the ID of slave unit 1 = master unit's ID × 2 + 1, and the ID of slave unit 2 = master unit's ID × 2 + 2.

[0039] In fact, IMU2b is connected to IMU2a as slave unit 1, and IMU2c is connected to IMU2a as slave unit 2. Therefore, when the communication interface circuit 31 of IMU2a receives a multi-unit connection mode command from the host device 3, the communication interface circuit 32 of IMU2a sends a command to initialize IMU2b to the communication interface circuit 31 of IMU2b, and a command to initialize IMU2c to the communication interface circuit 31 of IMU2c.

[0040] Next, in step S3, IMU2b receives an initial setup command, sets itself as slave unit 1, and sends initial setup commands to slave units 3 and 4. Specifically, the control unit 40 of IMU2b recognizes itself as slave unit 1 by receiving an initial setup command from IMU2a that includes the ID of slave unit 1=1, and sets its own ID as the ID of slave unit 1=1 in register 51. Also, since the control unit 40 of IMU2b is slave unit 1, it assumes that slave units 3 and 4 are connected to the communication interface circuit 32, and sends an initial setup command to slave unit 2 that includes the ID of slave unit 2, and sends an initial setup command to slave unit 4 that includes the ID of slave unit 4. The ID of slave unit 3 is 3, and the ID of slave unit 4 is 4. That is, for the ID of slave unit 1=1, the relationship is that the ID of slave unit 3 = the ID of slave unit 1 × 2 + 1, and the ID of slave unit 4 = the ID of slave unit 1 × 2 + 2.

[0041] Next, in step S4, IMU2b transmits connection information to IMU2a that can identify the number of slave units connected to it. Specifically, the control unit 40 of IMU2b generates connection information that can identify the number of IMUs that will become slave units connected to the communication interface circuit 32, and the communication interface circuit 31 of IMU2b transmits this connection information to IMU2a's communication interface The data is sent to the interface circuit 32. Since slave units 3 and 4 are not connected to the communication interface circuit 32 of IMU2b, there is no response from slave units 3 and 4 to the initial setup command. Therefore, IMU2b sends connection information to IMU2a indicating that the number of connected slave units is 0.

[0042] Similarly, in step S5, IMU2c receives an initial setup command, sets itself as slave unit 2, and sends initial setup commands to slave units 5 and 6. Specifically, the control unit 40 of IMU2c recognizes itself as slave unit 2 by receiving an initial setup command from IMU2a that includes the ID of slave unit 2, and sets the ID of slave unit 2, ID=2, as its own ID in register 51. Also, since the control unit 40 of IMU2c is slave unit 2, it assumes that slave units 5 and 6 are connected to the communication interface circuit 32, and sends an initial setup command to slave unit 5 that includes the ID of slave unit 5, and sends an initial setup command to slave unit 6 that includes the ID of slave unit 6. The ID of slave unit 5 is 5, and the ID of slave unit 6 is 6. That is, for the ID of slave unit 2, ID=2, the relationship is that the ID of slave unit 5 = ID of slave unit 2 × 2 + 1, and the ID of slave unit 6 = ID of slave unit 2 × 2 + 2.

[0043] Next, in step S6, IMU2c transmits connection information to IMU2a that allows it to identify the number of slave devices connected to it. Specifically, the control unit 40 of IMU2c generates connection information that allows it to identify the number of IMUs that will become slave devices connected to the communication interface circuit 32, and the communication interface circuit 31 of IMU2c transmits this connection information to the communication interface circuit 32 of IMU2a. Since slave devices 5 and 6 are not connected to the communication interface circuit 32 of IMU2c, there is no response from slave devices 5 and 6 to the initial setup command, so IMU2c transmits connection information to IMU2a indicating that the number of connected slave devices is 0.

[0044] Finally, in step S7, IMU2a receives connection information from IMU2b and 2c and transmits connection information to the host device 3 that allows it to identify the number of IMUs connected to the host device 3. Specifically, the control unit 40 of IMU2a generates connection information that allows it to identify the number of IMUs connected to the host device 3 based on the connection information received from IMU2b and 2c, and the communication interface circuit 31 of IMU2a transmits this connection information to the host device 3. In other words, IMU2a recognizes that it and IMU2b and 2c are connected to the host device 3 and transmits connection information to the host device 3 indicating that the number of connections is 3.

[0045] The signal processing unit 20 of IMU2a performs calculations based on the connection information generated by the control unit 40. Specifically, the control unit 40 stores connection information indicating that the number of connections is 3 in the register 51. The synthesis processing unit 23 then adds the 3-axis acceleration values, 3-axis angular velocity values, and temperature values ​​contained in the matched data ALD, ALD2, and ALD3, and divides by the number of connections (=3) specified by the connection information stored in the register 51 to calculate the average value of each of the 3-axis acceleration values, 3-axis angular velocity values, and temperature values, thereby generating the measurement data DO.

[0046] In the first embodiment, IMU2b is an example of a "first inertial measurement unit," IMU2c is an example of a "second inertial measurement unit," and IMU2a is an example of a "third inertial measurement unit." Furthermore, the communication interface circuit 31 is an example of a "first communication unit," and the communication interface circuit 32 is an example of a "second communication unit." Also, the measurement data DO output from the signal processing unit 20 of IMU2b is an example of a "first signal," and the measurement data DO output from the signal processing unit 20 of IMU2c is an example of a "second signal." Furthermore, the sensor data SD, which is the output signal of the inertial sensor 10 of IMU2a, is an example of a "third signal," and the measurement data DO output from the signal processing unit 20 of IMU2a is an example of a "fourth signal." Also, the connection information generated by IMU2b is an example of "first connection information." The connection information generated by MU2c is an example of "second connection information," and the connection information generated by IMU2a is an example of "third connection information."

[0047] 1-4. Effects As explained above, according to the inertial sensor device 1 of the first embodiment, IMU2a generates measurement data DO by performing a synthesis process on the matched data ALD, ALD2, and ALD3 based on the output signals of the respective inertial sensors 10 of IMU2a, 2b, and 2c. Therefore, it is possible to generate highly accurate measurement data DO with random noise reduced to 1 / √3. Furthermore, according to the inertial sensor device 1 of the first embodiment, since IMU2b and 2c are connected in parallel to IMU2a, the increase in calculation processing time and communication time is suppressed compared to the case where IMU2b and 2c are connected in series to IMU2a. In addition, if IMU2b and 2c are connected in series to IMU2a, for example, if IMU2b fails, IMU2b and 2c become unusable. However, according to the inertial sensor device 1 of the first embodiment, if IMU2b fails, only IMU2b becomes unusable, thus suppressing a decrease in calculation accuracy.

[0048] Furthermore, according to the inertial sensor device 1 of the first embodiment, IMUs 2b and 2c transmit connection information to IMU 2a, respectively. Therefore, IMU 2a can recognize the number of IMUs connected to the host device 3 based on the connection information from IMUs 2b and 2c, and perform appropriate synthesis processing. In addition, in the inertial sensor device 1 of the first embodiment, IMU 2a can recognize the number of IMUs connected to the host device 3 through communication between IMUs 2a, 2b, and 2c, so there is no need to pre-store connection information in the non-volatile memory 52 of IMU 2a. Consequently, the inertial sensor device 1 of the first embodiment can reduce production costs and achieve high expandability because it is easy to increase or decrease the number of IMUs.

[0049] Furthermore, according to the inertial sensor device 1 of the first embodiment, the host device 3 can recognize the number of IMUs connected to it based on the connection information transmitted from the IMU 2a, and can process the measurement data DO appropriately according to the number of connections. In addition, according to the inertial sensor device 1 of the first embodiment, there is no need to store connection information in advance in the non-volatile memory of the host device 3, which increases the flexibility and expandability of the system configuration.

[0050] Furthermore, in the inertial sensor device 1 of the first embodiment, the initial settings of IMUs 2a, 2b, and 2c are performed by a multiple-unit connection mode command transmitted from the host device 3, so there is no need to pre-store initial setting information in the non-volatile memory 52 of IMUs 2a, 2b, and 2c. Therefore, the inertial sensor device 1 of the first embodiment can reduce production costs and increase the flexibility and expandability of system construction.

[0051] 2. Second Embodiment In the following description of the second embodiment, the same reference numerals are used for components similar to those in the first embodiment, and explanations that overlap with those in the first embodiment will be omitted or simplified. The main points to be described will be those that differ from the first embodiment.

[0052] Figure 4 shows the overall configuration of the inertial sensor device 1 of the second embodiment. As shown in Figure 4, the inertial sensor device 1 of the second embodiment has seven IMUs 2a to 2g and is connected to an external device, the host device 3.

[0053] Each of the IMUs 2a to 2g has an inertial sensor, and the output from the inertial sensor is Predetermined signal processing is performed on the data to generate measurement data. The inertial sensors in each of the IMUs 2a to 2g detect the same type of physical quantity. For example, each inertial sensor may detect acceleration in one axis or two or more axes, or it may detect angular velocity in one axis or two or more axes, or it may detect 3-axis acceleration and 3-axis angular velocity. In the following explanation, we will assume that each inertial sensor measures 3-axis acceleration and 3-axis angular velocity.

[0054] IMU2a is connected to host device 3 and can communicate with host device 3. In communication between IMU2a and host device 3, host device 3 acts as the master and IMU2a as the slave. That is, host device 3 sends various commands to IMU2a, and IMU2a performs processing according to the received commands.

[0055] Furthermore, IMU2a is connected to two IMU2b and 2c units, and can communicate with each of them. In communication between IMU2a and each of IMU2b and 2c, IMU2a acts as the master, and IMU2b and 2c act as slaves. That is, IMU2a sends various commands to IMU2b and 2c, and IMU2b and 2c each perform processing according to the received commands.

[0056] Furthermore, IMU2b is connected to two IMU2d and 2e units, and can communicate with each of them. In communication between IMU2b and each of IMU2d and 2e, IMU2b acts as the master, and IMU2d and 2e act as slaves. That is, IMU2b sends various commands to IMU2d and 2e, and IMU2d and 2e each perform processing according to the received commands.

[0057] Furthermore, IMU2c is connected to two IMU2f and 2g units, and can communicate with each of them. In communication between IMU2c and each of IMU2f and 2g, IMU2c acts as the master, and IMU2f and 2g act as slaves. In other words, IMU2c sends various commands to IMU2f and 2g, and IMU2f and 2g each perform processing according to the received commands.

[0058] Thus, IMU2a functions as a "master" capable of communicating with host device 3, while the other IMUs 2b to 2g function as "slave" units. In the following, IMUs 2b, 2c, 2d, 2e, 2f, and 2g will be referred to as "slave 1," "slave 2," "slave 3," "slave 4," "slave 5," and "slave 6," respectively.

[0059] When IMU2a receives a sampling start command from host device 3 requesting the transmission of measurement data, it samples the data detected by its own inertial sensor, performs predetermined signal processing, and also sends sampling start commands to IMU2b and 2c, respectively.

[0060] When IMU2b receives a sampling start command from IMU2a, it samples the data detected by its own inertial sensor, performs predetermined signal processing, and also sends sampling start commands to IMU2d and 2e, respectively.

[0061] When IMU2d and 2e receive a sampling start command from IMU2b, they sample the data detected by their own inertial sensors, perform predetermined signal processing, and transmit the resulting 3-axis acceleration and 3-axis angular velocity measurement data to IMU2b. IMU2b acquires the measurement data from IMU2d and 2e and performs a synthesis process on the acquired measurement data and the 3-axis acceleration and 3-axis angular velocity data obtained by its own predetermined signal processing. This synthesis process may be, for example, an addition process. Then, IMU2b performs a measurement including the measured values ​​of 3-axis acceleration and 3-axis angular velocity obtained by the synthesis process. Send data to IMU2a.

[0062] When IMU2c receives a sampling start command from IMU2a, it samples the data detected by its own inertial sensor, performs predetermined signal processing, and also sends sampling start commands to IMU2f and 2g, respectively.

[0063] When IMU2f and 2g receive a sampling start command from IMU2c, they sample the data detected by their own inertial sensors, perform predetermined signal processing, and transmit the resulting 3-axis acceleration and 3-axis angular velocity measurement data to IMU2c. IMU2c acquires the measurement data from both IMU2f and 2g and performs a synthesis process on the acquired measurement data and the 3-axis acceleration and 3-axis angular velocity data obtained by its own predetermined signal processing. This synthesis process may be, for example, an addition process. Then, IMU2c transmits the measurement data, including the 3-axis acceleration and 3-axis angular velocity measurements obtained by the synthesis process, to IMU2a.

[0064] IMU2a acquires measurement data from IMU2b and 2c respectively, and performs a synthesis process on the acquired measurement data and the 3-axis acceleration and 3-axis angular velocity data obtained by its own predetermined signal processing. This synthesis process may be, for example, an averaging process. Then, IMU2a transmits the measurement data, including the measured values ​​of 3-axis acceleration and 3-axis angular velocity obtained by the synthesis process, to the host device 3.

[0065] IMU2a outputs a clock signal CLK generated by its built-in oscillator circuit to IMU2b-2g. Each of IMU2a-2g performs signal processing in synchronization with the clock signal CLK. Therefore, by sampling the output signals of the inertial sensors at the same edge of the clock signal CLK, IMU2a can synthesize the seven data points measured simultaneously by each of IMU2a-2g.

[0066] IMUs 2a to 2g have the same configuration, which is the same as IMUs 2a, 2b, and 2c in the first embodiment shown in Figure 2. That is, IMUs 2a to 2g include an inertial sensor 10, a signal processing unit 20, communication interface circuits 31 and 32, a control unit 40, a memory unit 50, an oscillator circuit 60, and a switch 70, similar to IMUs 2a, 2b, and 2c in Figure 2. The functions of the inertial sensor 10, signal processing unit 20, communication interface circuits 31 and 32, control unit 40, memory unit 50, and oscillator circuit 60 are the same as in the first embodiment. Note that IMUs 2a to 2g do not necessarily have the same configuration.

[0067] In the second embodiment, the oscillation signal output from the oscillation circuit 60 is output as a clock signal CLK to IMUs 2b to 2g via the ON switch 70. In each of IMUs 2b to 2g, the oscillation circuit 60 is set to stop operating, and the switch 70 is set to the OFF state. Then, each part of IMUs 2b to 2g operates in synchronization with the clock signal CLK supplied from IMU 2a.

[0068] The synthesis processing unit 23 of IMU2a performs synthesis processing on the matched data ALD output from the matching processing unit 22 and the matched data ALD2 and ALD3 acquired from IMU2b and 2c respectively via the communication interface circuit 32, and outputs the synthesized data, which is the measurement data DO. The synthesis processing unit 23 of IMU2b performs synthesis processing on the matched data ALD output from the matching processing unit 22 and the matched data ALD2 and ALD3 acquired from IMU2d and 2e respectively via the communication interface circuit 32, and outputs the synthesized data, which is the measurement data DO. The synthesis processing unit 23 of IMU2c performs synthesis processing on the matched data ALD output from the matching processing unit 22 and the matched data ALD2 and ALD3 acquired from IMU2f and 2g respectively via the communication interface circuit 32, and Outputs the measurement data DO, which is the data after maturation.

[0069] The synthesis process performed by the synthesis processing unit 23 of IMU2b,2c may be, for example, an addition process. Specifically, the synthesis processing unit 23 calculates the sum of the acceleration values ​​for the X, Y, and Z axes by adding together the acceleration values ​​for the X, Y, and Z axes contained in the matched data ALD, together the acceleration values ​​for the X, Y, and Z axes contained in the matched data ALD2, and together the acceleration values ​​for the X, Y, and Z axes contained in the matched data ALD3. Similarly, the synthesis processing unit 23 calculates the sum of the angular velocity values ​​for the X, Y, and Z axes by adding together the angular velocity values ​​for the X, Y, and Z axes contained in the matched data ALD, together the angular velocity values ​​for the X, Y, and Z axes contained in the matched data ALD2, and together the angular velocity values ​​for the X, Y, and Z axes contained in the matched data ALD3. Alternatively, the synthesis processing unit 23 may calculate the sum of temperatures by adding the temperature values ​​included in the matched data ALD, the temperature values ​​included in the matched data ALD2, and the temperature values ​​included in the matched data ALD3.

[0070] Since the communication interface circuits 32 of IMU2d, 2e, 2f, and 2g are not connected to the IMU, the matching data ALD2 and ALD3 are not input to the respective synthesis processing units 23 of IMU2d, 2e, 2f, and 2g. Therefore, the respective synthesis processing units 23 of IMU2d, 2e, 2f, and 2g output the matching data ALD as the measurement data DO.

[0071] The communication interface circuit 31 of IMU2a is connected to the host device 3, receives various commands transmitted from the host device 3, and outputs them to the control unit 40. The communication interface circuit 31 of IMU2b is connected to the communication interface circuit 32 of IMU2a, receives various commands transmitted from IMU2a, and outputs them to the control unit 40. The communication interface circuit 31 of IMU2c is connected to the communication interface circuit 32 of IMU2a, receives various commands transmitted from IMU2a, and outputs them to the control unit 40.

[0072] The communication interface circuit 31 of IMU2d is connected to the communication interface circuit 32 of IMU2b, receives various commands transmitted from IMU2b, and outputs them to the control unit 40. The communication interface circuit 31 of IMU2e is connected to the communication interface circuit 32 of IMU2b, receives various commands transmitted from IMU2b, and outputs them to the control unit 40.

[0073] The communication interface circuit 31 of IMU2f is connected to the communication interface circuit 32 of IMU2c, receives various commands transmitted from IMU2c, and outputs them to the control unit 40. The communication interface circuit 31 of IMU2g is connected to the communication interface circuit 32 of IMU2c, receives various commands transmitted from IMU2c, and outputs them to the control unit 40.

[0074] The communication standard used via the communication interface circuit 31 of IMU2a~2g may be, for example, UART, SPI, or any other standard.

[0075] The communication interface circuit 32 of IMU2a is connected to the respective communication interface circuits 31 of IMU2b and 2c. The control unit 40 of IMU2a generates various commands for IMU2b and 2c, and transmits the generated commands to the respective communication interface circuits 31 of IMU2b and 2c via the communication interface circuit 32.

[0076] The communication interface circuit 32 of IMU2b connects to the respective communication interfaces of IMU2d and 2e. - Connected to the interface circuit 31, the control unit 40 of IMU2b generates various commands for IMU2d and 2e, and transmits the generated commands to the respective communication interface circuits 31 of IMU2d and 2e via the communication interface circuit 32.

[0077] The communication interface circuit 32 of IMU2c is connected to the respective communication interface circuits 31 of IMU2f and 2g. The control unit 40 of IMU2c generates various commands for IMU2f and 2g, and transmits the generated commands to the respective communication interface circuits 31 of IMU2f and 2g via the communication interface circuit 32.

[0078] The communication standard used for communication via the communication interface circuit 32 of IMU2a,2b,2c may be, for example, UART, SPI, or other standards.

[0079] For example, when the control unit 40 of IMU2a receives a command from the host device 3 via the communication interface circuit 31 requesting the transmission of measurement data DO, it sends a command via the communication interface circuit 32 to the respective communication interface circuits 31 of IMU2b and 2c requesting the transmission of measurement data DO.

[0080] In IMU2b, the control unit 40 receives the command via the communication interface circuit 31 and sends a command via the communication interface circuit 32 to the respective communication interface circuits 31 of IMU2d and 2e requesting the transmission of measurement data DO. In each of IMU2d and 2e, the control unit 40 receives the command via the communication interface circuit 31. Then, in IMU2d, under the control of the control unit 40, the communication interface circuit 31 transmits the measurement data DO output from the signal processing unit 20 to the communication interface circuit 32 of IMU2b. Similarly, in IMU2e, under the control of the control unit 40, the communication interface circuit 31 transmits the measurement data DO output from the signal processing unit 20 to the communication interface circuit 32 of IMU2b.

[0081] Subsequently, in IMU2b, the control unit 40 receives measurement data DO from IMU2d via the communication interface circuit 32 and outputs the received measurement data DO as matched data ALD2 to the synthesis processing unit 23 of the signal processing unit 20. Similarly, the control unit 40 receives measurement data DO from IMU2e via the communication interface circuit 32 and outputs the received measurement data DO as matched data ALD3 to the synthesis processing unit 23 of the signal processing unit 20. Then, in IMU2b, the signal processing unit 20 performs calculations on the matched data ALD2, ALD3 and sensor data SD, which is the output signal of the inertial sensor 10, and outputs measurement data DO. That is, the signal processing unit 20 generates matched data ALD based on sensor data SD using the correction processing unit 21 and the matching processing unit 22, and outputs measurement data DO by adding the matched data ALD, ALD2, and ALD3 using the synthesis processing unit 23. Then, the communication interface circuit 31 of IMU2b transmits the measurement data DO output from the signal processing unit 20 to the communication interface circuit 32 of IMU2a.

[0082] Furthermore, in IMU2c, the control unit 40 receives the command via the communication interface circuit 31 and sends a command via the communication interface circuit 32 to the respective communication interface circuits 31 of IMU2f and 2g requesting the transmission of measurement data DO. In each of IMU2f and 2g, the control unit 40 receives the command via the communication interface circuit 31. Then, in IMU2f, under the control of the control unit 40, the communication interface circuit 31 transmits the measurement data DO output from the signal processing unit 20 to the communication interface circuit 32 of IMU2c. Similarly, in IMU2g, under the control of the control unit 40, the communication interface circuit 31 transmits the measurement data DO output from the signal processing unit 20 to the communication interface circuit 32 of IMU2c.

[0083] Subsequently, in IMU2c, the control unit 40 receives measurement data DO from IMU2f via the communication interface circuit 32 and outputs the received measurement data DO as matched data ALD2 to the synthesis processing unit 23 of the signal processing unit 20. Similarly, the control unit 40 receives measurement data DO from IMU2g via the communication interface circuit 32 and outputs the received measurement data DO as matched data ALD3 to the synthesis processing unit 23 of the signal processing unit 20. Then, in IMU2c, the signal processing unit 20 performs calculations on the matched data ALD2, ALD3 and the sensor data SD, which is the output signal of the inertial sensor 10, and outputs measurement data DO. That is, the signal processing unit 20 generates matched data ALD based on the sensor data SD using the correction processing unit 21 and the matching processing unit 22, and outputs measurement data DO by adding the matched data ALD, ALD2, and ALD3 using the synthesis processing unit 23. Then, the communication interface circuit 31 of IMU2c transmits the measurement data DO output from the signal processing unit 20 to the communication interface circuit 32 of IMU2a.

[0084] Subsequently, in IMU2a, the control unit 40 receives measurement data DO from IMU2b via the communication interface circuit 32 and outputs the received measurement data DO as matched data ALD2 to the synthesis processing unit 23 of the signal processing unit 20. Similarly, the control unit 40 receives measurement data DO from IMU2c via the communication interface circuit 32 and outputs the received measurement data DO as matched data ALD3 to the synthesis processing unit 23 of the signal processing unit 20. In IMU2a, the signal processing unit 20 performs calculations on the matched data ALD2, ALD3 and sensor data SD, which is the output signal of the inertial sensor 10, and outputs measurement data DO. That is, the signal processing unit 20 generates matched data ALD based on sensor data SD using the correction processing unit 21 and the matching processing unit 22, and outputs measurement data DO by performing averaging processing on the matched data ALD, ALD2, and ALD3 using the synthesis processing unit 23. Then, the communication interface circuit 31 of IMU2a transmits the measurement data DO output from the signal processing unit 20 to the host device 3.

[0085] Furthermore, IMUs 2a to 2g may function as a correction processing unit 21, a matching processing unit 22, a synthesis processing unit 23, and a control unit 40, respectively, by having a processing unit such as a CPU or microcontroller unit (not shown) execute a program stored in the non-volatile memory 52.

[0086] When the inertial sensor device 1 receives a multi-device connection mode command from the host device 3, it performs the initial setup of IMUs 2a to 2g. Figure 5 is a flowchart showing an example of the initial setup procedure for IMUs 2a to 2g in the second embodiment.

[0087] As shown in Figure 5, in step S10, when IMU2a receives an initial setup command, which is a multiple-device connection mode command, from the host device 3, first in step S20, IMU2a sets the master device ID for itself and sends initial setup commands to slave device 1 and slave device 2.

[0088] The control unit 40 of IMU2a recognizes itself as the master unit upon receiving a multi-unit connection mode command from the host device 3, and sets the master unit's ID=0 in register 51 as its own ID. Also, because it is the master unit, the control unit 40 of IMU2a assumes that slave units 1 and 2 are connected to the communication interface circuit 32, and sends an initial setup command including the ID of slave unit 1 to slave unit 1, and an initial setup command including the ID of slave unit 2 to slave unit 2. The ID of slave unit 1 is 1, and the ID of slave unit 2 is 2. That is, with respect to the master unit's ID=0, the relationship is that the ID of slave unit 1 = master unit's ID × 2 + 1, and the ID of slave unit 2 = master unit's ID × 2 + 2.

[0089] In fact, IMU2b is connected to IMU2a as slave unit 1, and I MU2c is connected. Therefore, when the communication interface circuit 31 of IMU2a receives a multi-unit connection mode command from the host device 3, the communication interface circuit 32 of IMU2a sends a command to initialize IMU2b to the communication interface circuit 31 of IMU2b and a command to initialize IMU2c to the communication interface circuit 31 of IMU2c.

[0090] Next, in step S30, IMU2b receives an initial setup command, sets itself as slave unit 1, and sends initial setup commands to slave units 3 and 4. Specifically, the control unit 40 of IMU2b recognizes itself as slave unit 1 by receiving an initial setup command from IMU2a that includes the ID of slave unit 1=1, and sets its own ID as the ID of slave unit 1=1 in register 51. Also, since the control unit 40 of IMU2b is slave unit 1, it assumes that slave units 3 and 4 are connected to the communication interface circuit 32, and sends an initial setup command to slave unit 3 that includes the ID of slave unit 3, and sends an initial setup command to slave unit 4 that includes the ID of slave unit 4. The ID of slave unit 3 is 3, and the ID of slave unit 4 is 4. That is, for the ID of slave unit 1=1, the relationship is that the ID of slave unit 3 = the ID of slave unit 1 × 2 + 1, and the ID of slave unit 4 = the ID of slave unit 1 × 2 + 2.

[0091] Next, in step S40, IMU2d receives an initial setup command, sets itself as slave unit 3, and sends initial setup commands to slave units 7 and 8. Specifically, the control unit 40 of IMU2d recognizes itself as slave unit 3 by receiving an initial setup command from IMU2b that includes the ID of slave unit 3, and sets the ID of slave unit 3, ID=3, as its own ID in register 51. Also, since IMU2d is slave unit 3, the control unit 40 assumes that slave units 7 and 8 are connected to the communication interface circuit 32, and sends an initial setup command to slave unit 7 that includes the ID of slave unit 7, and sends an initial setup command to slave unit 8 that includes the ID of slave unit 8. The ID of slave unit 7 is 7, and the ID of slave unit 8 is 8. That is, for the ID of slave unit 3, ID=3, the relationship is that the ID of slave unit 7 = ID of slave unit 3 × 2 + 1, and the ID of slave unit 8 = ID of slave unit 3 × 2 + 2.

[0092] Next, in step S50, IMU2d transmits connection information to IMU2b that allows it to identify the number of slave units connected to it. Specifically, the control unit 40 of IMU2d generates connection information that allows it to identify the number of IMUs that will become slave units connected to the communication interface circuit 32, and the communication interface circuit 31 of IMU2d transmits this connection information to the communication interface circuit 32 of IMU2b. Since slave units 7 and 8 are not connected to the communication interface circuit 32 of IMU2d, there is no response from slave units 7 and 8 to the initial setup command, so IMU2d transmits connection information to IMU2b indicating that the number of connected slave units is 0.

[0093] Similarly, in process S60, IMU2e receives an initial setup command, sets itself as slave unit 4, and sends initial setup commands to slave units 9 and 10. Specifically, the control unit 40 of IMU2e recognizes itself as slave unit 4 by receiving an initial setup command from IMU2b that includes the ID of slave unit 4 (ID=4), and sets its own ID as the ID of slave unit 4 (ID=4) in register 51. Also, since the control unit 40 of IMU2e is slave unit 4, it assumes that slave units 9 and 10 are connected to the communication interface circuit 32, and sends an initial setup command to slave unit 9 that includes the ID of slave unit 9, and sends an initial setup command to slave unit 10 that includes the ID of slave unit 10. The ID of slave unit 9 is 9, and the ID of slave unit 10 is 10. That is, for the ID of slave unit 4 (ID=4), the relationship is: ID of slave unit 9 = ID of slave unit 4 × 2 + 1, and ID of slave unit 10 = ID of slave unit 4 × 2 + 2.

[0094] Next, in step S70, IMU2e transmits connection information to IMU2b that allows it to identify the number of slave devices connected to it. Specifically, the control unit 40 of IMU2e transmits the communication input Connection information is generated that can identify the number of IMUs that will become slave units connected to the surface circuit 32, and the communication interface circuit 31 of IMU2e transmits this connection information to the communication interface circuit 32 of IMU2b. Since slave units 9 and 10 are not connected to the communication interface circuit 32 of IMU2e, there is no response from slave units 9 and 10 to the initial setup command, so IMU2e transmits connection information to IMU2b indicating that the number of connected slave units is 0.

[0095] Next, in step S80, IMU2b receives connection information from IMU2d and 2e and transmits connection information to IMU2a that allows it to identify the number of IMUs connected to it. Specifically, the control unit 40 of IMU2b generates connection information that allows it to identify the number of IMUs connected to the communication interface circuit 32 based on the connection information received from IMU2d and 2e, and the communication interface circuit 31 of IMU2b transmits this connection information to the communication interface circuit 32 of IMU2a. IMU2b receives connection information from each of IMU2d and 2e indicating that the number of connected slaves is 0, and transmits connection information to IMU2a indicating that the number of connected slaves is 2.

[0096] Similarly, in process S90, IMU2c receives an initial setup command, sets itself as slave unit 2, and sends initial setup commands to slave units 5 and 6. Specifically, the control unit 40 of IMU2c recognizes itself as slave unit 2 by receiving an initial setup command from IMU2a that includes the ID of slave unit 2, and sets the ID of slave unit 2, ID=2, as its own ID in register 51. Also, since the control unit 40 of IMU2c is slave unit 2, it assumes that slave units 5 and 6 are connected to the communication interface circuit 32, and sends an initial setup command to slave unit 5 that includes the ID of slave unit 5, and sends an initial setup command to slave unit 6 that includes the ID of slave unit 6. The ID of slave unit 5 is 5, and the ID of slave unit 6 is 6. That is, for the ID of slave unit 2, ID=2, the relationship is that the ID of slave unit 5 = ID of slave unit 2 × 2 + 1, and the ID of slave unit 6 = ID of slave unit 2 × 2 + 2.

[0097] Next, in step S100, IMU2f receives an initial setup command, sets itself as slave unit 5, and sends initial setup commands to slave units 11 and 12. Specifically, the control unit 40 of IMU2f recognizes itself as slave unit 5 by receiving an initial setup command from IMU2c that includes the ID of slave unit 5 (ID=5), and sets its own ID as the ID of slave unit 5 (ID=5) in register 51. Also, since the control unit 40 of IMU2f is slave unit 5, it assumes that slave units 11 and 12 are connected to the communication interface circuit 32, and sends an initial setup command to slave unit 11 that includes the ID of slave unit 11, and sends an initial setup command to slave unit 12 that includes the ID of slave unit 12. The ID of slave unit 11 is 11, and the ID of slave unit 12 is 12. That is, for slave unit 5 (ID=5), the relationship is: Slave unit 11 (ID=Slave unit 5 (ID) × 2 + 1), and Slave unit 12 (ID=Slave unit 5 (ID) × 2 + 2).

[0098] Next, in step S110, IMU2f transmits connection information to IMU2c that allows it to identify the number of slave units connected to it. Specifically, the control unit 40 of IMU2f generates connection information that allows it to identify the number of IMUs that will become slave units connected to the communication interface circuit 32, and the communication interface circuit 31 of IMU2f transmits this connection information to the communication interface circuit 32 of IMU2c. Since slave units 11 and 12 are not connected to the communication interface circuit 32 of IMU2f, there is no response from slave units 11 and 12 to the initial setup command, so IMU2f transmits connection information to IMU2c indicating that the number of connected slave units is 0.

[0099] Similarly, in step S120, IMU2g receives an initial setup command, sets itself as slave unit 6, and sends an initial setup command to slave units 13 and 14. Specifically, the control unit 40 of IMU2g receives an initial setup command from IMU2c that includes ID=6 of slave unit 6. By sending a message, the IMU2g recognizes itself as slave unit 6 and sets its own ID, slave unit 6's ID=6, in register 51. Also, the control unit 40 of the IMU2g, being slave unit 6 itself, assumes that slave units 13 and 14 are connected to the communication interface circuit 32, and sends an initial setup command to slave unit 13 that includes the ID of slave unit 13, and sends an initial setup command to slave unit 14 that includes the ID of slave unit 14. The ID of slave unit 13 is 13, and the ID of slave unit 14 is 14. That is, for slave unit 6's ID=6, the relationship is slave unit 13's ID = slave unit 6's ID × 2 + 1, and slave unit 14's ID = slave unit 6's ID × 2 + 2.

[0100] Next, in step S130, IMU2g transmits connection information to IMU2c that allows it to identify the number of slave devices connected to it. Specifically, the control unit 40 of IMU2g generates connection information that allows it to identify the number of IMUs that will become slave devices connected to the communication interface circuit 32, and the communication interface circuit 31 of IMU2g transmits this connection information to the communication interface circuit 32 of IMU2c. Since slave devices 13 and 14 are not connected to the communication interface circuit 32 of IMU2g, there is no response from slave devices 13 and 14 to the initial setup command, so IMU2g transmits connection information to IMU2c indicating that the number of connected slave devices is 0.

[0101] Next, in step S140, IMU2c receives connection information from IMU2f and 2g and transmits connection information to IMU2a that allows it to identify the number of IMUs connected to it. Specifically, the control unit 40 of IMU2c generates connection information that allows it to identify the number of IMUs connected to the communication interface circuit 32 based on the connection information received from IMU2f and 2g, and the communication interface circuit 31 of IMU2c transmits this connection information to the communication interface circuit 32 of IMU2a. IMU2c receives connection information from each of IMU2f and 2g indicating that the number of connected slaves is 0, and transmits connection information to IMU2a indicating that the number of connected slaves is 2.

[0102] Finally, in step S150, IMU2a receives connection information from IMU2b and 2c and transmits connection information to the host device 3 that allows it to identify the number of IMUs connected to the host device 3. Specifically, the control unit 40 of IMU2a generates connection information that allows it to identify the number of IMUs connected to the host device 3 based on the connection information received from IMU2b and 2c, and the communication interface circuit 31 of IMU2a transmits this connection information to the host device 3. In other words, IMU2a recognizes that it and six IMUs (IMU2b to 2g) are connected to the host device 3 and transmits connection information to the host device 3 indicating that the number of connections is seven.

[0103] The signal processing unit 20 of IMU2a performs calculations based on the connection information generated by the control unit 40. Specifically, the control unit 40 stores connection information indicating that the number of connections is 7 in the register 51. The synthesis processing unit 23 then adds the 3-axis acceleration values, 3-axis angular velocity values, and temperature values ​​contained in the matched data ALD, ALD2, and ALD3, and divides by the number of connections (=7) specified by the connection information stored in the register 51 to calculate the average values ​​of the 3-axis acceleration values, 3-axis angular velocity values, and temperature values, thereby generating the measurement data DO.

[0104] In the second embodiment, IMU2d is an example of a "first inertial measurement unit," IMU2e is an example of a "second inertial measurement unit," IMU2b is an example of a "third inertial measurement unit," and IMU2a is an example of a "fourth inertial measurement unit." IMU2f is another example of a "first inertial measurement unit," IMU2g is another example of a "second inertial measurement unit," and IMU2c is another example of a "third inertial measurement unit." Furthermore, the communication interface circuit 31 is an example of a "first communication unit," and the communication interface circuit 32 is an example of a "second communication unit." Also, the measurement data DO output from the signal processing unit 20 of IMU2d is an example of a "first signal," and the output from the signal processing unit 20 of IMU2e is an example of a "first signal." The transmitted measurement data DO is an example of a "second signal," the sensor data SD, which is the output signal of the inertial sensor 10 of IMU2b, is an example of a "third signal," and the measurement data DO output from the signal processing unit 20 of IMU2b is an example of a "fourth signal." Furthermore, the measurement data DO output from the signal processing unit 20 of IMU2f is another example of a "first signal," the measurement data DO output from the signal processing unit 20 of IMU2g is another example of a "second signal," the sensor data SD, which is the output signal of the inertial sensor 10 of IMU2c, is another example of a "third signal," and the measurement data DO output from the signal processing unit 20 of IMU2c is another example of a "fourth signal." Furthermore, the sensor data SD, which is the output signal of the inertial sensor 10 of IMU2a, is an example of a "fifth signal," and the measurement data DO output from the signal processing unit 20 of IMU2a is an example of a "sixth signal." Furthermore, the connection information generated by IMU2d is an example of "first connection information," the connection information generated by IMU2e is an example of "second connection information," the connection information generated by IMU2b is an example of "third connection information," and the connection information generated by IMU2a is an example of "fourth connection information." Additionally, the connection information generated by IMU2f is another example of "first connection information," the connection information generated by IMU2g is another example of "second connection information," and the connection information generated by IMU2c is another example of "third connection information."

[0105] As described above, according to the inertial sensor device 1 of the second embodiment, IMU2a performs synthesis processing on the matched data ALD, ALD2, and ALD3 based on the output signals of each inertial sensor 10 of IMU2a to 2g to generate measurement data DO, so that highly accurate measurement data DO can be generated with random noise reduced to 1 / √7. Furthermore, according to the inertial sensor device 1 of the second embodiment, IMU2b and 2c are connected in parallel to IMU2a, IMU2d and 2e are connected in parallel to IMU2b, and IMU2f and 2g are connected in parallel to IMU2c, so the increase in calculation processing time and communication time is suppressed compared to the case where IMU2b to 2g are connected in series to IMU2a. Furthermore, if IMU2b~2g are connected in series with IMU2a, for example, if IMU2b fails, IMU2c~2g will become unusable. In contrast, with the inertial sensor device 1 of the second embodiment, if IMU2b fails, only IMU2b,2d, and2e become unusable, thus suppressing a decrease in calculation accuracy.

[0106] Furthermore, according to the inertial sensor device 1 of the second embodiment, IMU2d and 2e transmit connection information to IMU2b, IMU2f and 2g transmit connection information to IMU2c, IMU2b transmits connection information generated based on the connection information of IMU2d and 2e to IMU2a, and IMU2c transmits connection information generated based on the connection information of IMU2f and 2g to IMU2a. As a result, IMU2a can recognize the number of IMUs connected to the host device 3 based on the connection information of IMU2b and 2c and perform appropriate synthesis processing. In addition, in the inertial sensor device 1 of the second embodiment, IMU2a can recognize the number of IMUs connected to the host device 3 through communication between IMU2a and 2g, so there is no need to pre-store connection information in the non-volatile memory 52 of IMU2a.Therefore, according to the inertial sensor device 1 of the second embodiment, production costs can be reduced and high expandability can be achieved because it is easy to increase or decrease the number of IMUs.

[0107] Furthermore, according to the inertial sensor device 1 of the second embodiment, the host device 3 can recognize the number of IMUs connected to it based on the connection information transmitted from the IMU 2a, and can process the measurement data DO appropriately according to the number of connections. In addition, according to the inertial sensor device 1 of the second embodiment, there is no need to store connection information in advance in the non-volatile memory of the host device 3, which increases the flexibility and expandability of the system configuration.

[0108] Furthermore, in the inertial sensor device 1 of the second embodiment, the initial settings of IMUs 2a to 2g are performed by a multiple-unit connection mode command transmitted from the host device 3, so there is no need to pre-store initial setting information in the non-volatile memory 52 of IMUs 2a to 2g. Therefore, the inertial sensor device 1 of the second embodiment can reduce production costs and increase the flexibility and expandability of system construction.

[0109] 3. Third Embodiment In the following description of the third embodiment, the same reference numerals are used for components similar to those in the first or second embodiment. Descriptions that overlap with those of the first or second embodiment will be omitted or simplified, and the differences from the first and second embodiments will be described primarily.

[0110] The overall configuration of the inertial sensor device 1 of the third embodiment is the same as that of Figure 1, so its illustration is omitted. Figure 6 shows an example of the configuration of IMUs 2a, 2b, and 2c included in the inertial sensor device 1 of the third embodiment. The IMUs 2a, 2b, and 2c in the third embodiment differ from those in the IMUs 2a, 2b, and 2c of the first embodiment shown in Figure 2 in that the signal processing unit 20 includes an anomaly detection unit 24 in addition to the correction processing unit 21, matching processing unit 22, and synthesis processing unit 23.

[0111] The anomaly detection unit 24 included in the signal processing unit 20 of IMU2a determines whether the matched data ALD2 output from the signal processing unit 20 of IMU2b, the matched data ALD3 output from the signal processing unit 20 of IMU2c, and the matched data ALD generated by performing predetermined processing, namely correction processing and matching processing, on the output signal of the inertial sensor 10 of IMU2a are normal or abnormal. Note that the matched data ALD of IMU2a is an example of the "fifth signal".

[0112] Specifically, the anomaly detection unit 24 of the IMU 2a determines whether the measured values ​​of 3-axis acceleration, 3-axis angular velocity, and temperature included in the matched data ALD, ALD2, and ALD3 are normal or abnormal. For example, if the difference between the measured value of X-axis acceleration included in the matched data ALD and the measured value of X-axis acceleration included in the matched data ALD2 is smaller than the first threshold, and the difference between the measured value of X-axis acceleration included in the matched data ALD and the measured value of X-axis acceleration included in the matched data ALD3 is greater than the second threshold (which is greater than or equal to the first threshold), and the difference between the measured value of X-axis acceleration included in the matched data ALD2 and the measured value of X-axis acceleration included in the matched data ALD3 is greater than the second threshold, then the anomaly detection unit 24 may determine that the measured values ​​of X-axis acceleration included in the matched data ALD and ALD2 are normal, and the measured value of X-axis acceleration included in the matched data ALD3 is abnormal. Furthermore, for example, the anomaly detection unit 24 may determine that the measured value of X-axis acceleration included in the matched data ALD3 is abnormal if, during a period in which the measured values ​​of X-axis acceleration included in the matched data ALD and ALD2 respectively change, the measured value of X-axis acceleration included in the matched data ALD3 does not change.

[0113] The anomaly detection unit 24 then outputs determination information to the synthesis processing unit 23 indicating whether the measured values ​​of the three-axis acceleration, three-axis angular velocity, and temperature included in the matched data ALD, ALD2, and ALD3 are normal or abnormal.

[0114] The synthesis processing unit 23 of IMU2a performs synthesis processing using the data from the matched data ALD, ALD2, and ALD3 that has been determined to be normal, based on the judgment information output from the anomaly detection unit 24. The synthesis processing unit 23 then outputs measurement data DO, to which synthesis number information that can identify the number of data used in the synthesis processing is added to the data generated by the synthesis processing. Specifically, the synthesis processing unit 23 performs synthesis processing using the measurement values ​​of the 3-axis acceleration, 3-axis angular velocity, and temperature included in the matched data ALD, ALD2, and ALD3 that have been determined to be normal. The synthesis processing unit 23 then performs synthesis processing The system outputs measurement data DO, which is the generated data to which composite number information is added, including the number of measured values ​​used in the composite processing for each of the measured values ​​of 3-axis acceleration, 3-axis angular velocity, and temperature. For example, if the measured values ​​of X-axis acceleration included in the matched data ALD and ALD2 are determined to be normal, but the measured value of X-axis acceleration included in the matched data ALD3 is determined to be abnormal, the composite processing unit 23 adds the measured values ​​of X-axis acceleration included in the normal matched data ALD and ALD2 and divides by 2, which is the number of normal data points, to calculate the average value of X-axis acceleration. The composite processing unit 23 then outputs measurement data DO, which is the generated data by the composite processing to which composite number information is added, including the number of measured values ​​of 3-axis acceleration used in the composite processing (=2).

[0115] Then, the communication interface circuit 31 of the IMU2a, under the control of the control unit 40, transmits the measurement data DO, to the host device 3, which has composite number information added to it and is output from the signal processing unit 20.

[0116] The overall configuration of the inertial sensor device 1 in the third embodiment may be the same as in Figure 4, with seven IMUs 2a to 2g connected. In this case, IMUs 2a to 2g have the same configuration, which is the same as IMUs 2a, 2b, and 2c shown in Figure 6. However, IMUs 2a to 2g do not have to have the same configuration.

[0117] The anomaly detection unit 24 included in the signal processing unit 20 of IMU2b determines whether the matched data ALD2 output from the signal processing unit 20 of IMU2d, the matched data ALD3 output from the signal processing unit 20 of IMU2e, and the matched data ALD generated by performing predetermined processing, namely correction processing and matching processing, on the output signal of the inertial sensor 10 of IMU2b are normal or abnormal. Note that the matched data ALD of IMU2a is an example of the "seventh signal".

[0118] Specifically, the anomaly detection unit 24 of IMU2b determines whether the measured values ​​of 3-axis acceleration, 3-axis angular velocity, and temperature included in the matched data ALD, ALD2, and ALD3 are normal or abnormal, and outputs determination information indicating the determination result to the synthesis processing unit 23.

[0119] The synthesis processing unit 23 of IMU2b performs synthesis processing using the data determined to be normal from the matched data ALD, ALD2, and ALD3 based on the judgment information output from the anomaly detection unit 24, and outputs measurement data DO with synthesis number information that can identify the number of data used in the synthesis processing added to the data generated by the synthesis processing. Then, the communication interface circuit 31 of IMU2b, under the control of the control unit 40, transmits the measurement data DO with the added synthesis number information output from the signal processing unit 20 to the communication interface circuit 32 of IMU2a.

[0120] Similarly, the anomaly detection unit 24 included in the signal processing unit 20 of IMU2c determines whether the matched data ALD2 output from the signal processing unit 20 of IMU2f, the matched data ALD3 output from the signal processing unit 20 of IMU2g, and the matched data ALD generated by performing predetermined processing, namely correction processing and matching processing, on the output signal of the inertial sensor 10 of IMU2c are normal or abnormal. Specifically, the anomaly detection unit 24 of IMU2c determines whether the measured values ​​of 3-axis acceleration, 3-axis angular velocity, and temperature included in the matched data ALD, ALD2, and ALD3 are normal or abnormal, and outputs determination information indicating the determination result to the synthesis processing unit 23.

[0121] The synthesis processing unit 23 of the IMU2c uses the data that has been determined to be normal from the matched data ALD, ALD2, and ALD3 based on the determination information output from the anomaly detection unit 24. The system performs a synthesis process and outputs measurement data DO to which synthesis number information, which allows the number of data points used in the synthesis process to be identified, is added to the data generated by the synthesis process. Then, the communication interface circuit 31 of IMU2c, under the control of the control unit 40, transmits the measurement data DO with the synthesis number information added, output from the signal processing unit 20, to the communication interface circuit 32 of IMU2a.

[0122] The anomaly detection unit 24 included in the signal processing unit 20 of IMU2a determines whether the matched data ALD2 output from the signal processing unit 20 of IMU2b, the matched data ALD3 output from the signal processing unit 20 of IMU2c, and the matched data ALD generated by performing predetermined processing, namely correction processing and matching processing, on the output signal of the inertial sensor 10 of IMU2a are normal or abnormal. Specifically, the anomaly detection unit 24 of IMU2a determines whether the measured values ​​of 3-axis acceleration, 3-axis angular velocity, and temperature included in the matched data ALD, ALD2, and ALD3 are normal or abnormal, and outputs determination information indicating the determination result to the synthesis processing unit 23.

[0123] The synthesis processing unit 23 of IMU2a performs synthesis processing using the data determined to be normal from the matched data ALD, ALD2, and ALD3 based on the judgment information output from the anomaly detection unit 24. It then outputs measurement data DO, to which synthesis number information that can identify the number of data used in the synthesis processing is added to the data generated by the synthesis processing. The communication interface circuit 31 of IMU2a, under the control of the control unit 40, transmits the measurement data DO with the added synthesis number information, output from the signal processing unit 20, to the host device 3.

[0124] For example, consider a case where the anomaly detection unit 24 of IMU2b determines that the measured value of X-axis acceleration included in the matched data ALD3 output from the communication interface circuit 31 of IMU2e is abnormal, and the anomaly detection unit 24 of IMU2c determines that the measured value of X-axis acceleration included in the matched data ALD3 output from the communication interface circuit 31 of IMU2g is abnormal. In this case, the synthesis processing units 23 of IMU2b and 2c each add the measured values ​​of X-axis acceleration included in the normal matched data ALD and ALD2, and divide by 2, which is the number of normal data points, to calculate the average value of X-axis acceleration. Then, in each of IMU2b and 2c, the communication interface circuit 31 adds synthesis number information, which includes the number of 3-axis acceleration measured values ​​(=2) used in the synthesis process, to the data generated by the synthesis process, and transmits the measurement data DO to the communication interface circuit 32 of IMU2a. In IMU2a, if the anomaly detection unit 24 determines that all of the measured X-axis acceleration values ​​included in the matched data ALD, ALD2, and ALD3 are normal, the synthesis processing unit 23 adds the measured X-axis acceleration values ​​included in the matched data ALD, ALD2, and ALD3. That is, the synthesis processing unit 23 calculates the sum of the five X-axis acceleration values ​​measured by IMU2a, 2b, 2c, 2d, and 2f. Furthermore, based on the synthesis number information included in the matched data ALD2 and ALD3, the synthesis processing unit 23 identifies that the number of measured X-axis acceleration values ​​used in the synthesis process is 5, and calculates the average value by dividing the sum of the measured X-axis acceleration values ​​by 5. Then, the communication interface circuit 31 of IMU2a transmits the measurement data DO, which is the data generated by the synthesis process with synthesis number information including the number of measured 3-axis acceleration values ​​used in the synthesis process (=5), to the host device 3.

[0125] The other components of the inertial sensor device 1 in the third embodiment are the same as those in the first or second embodiment, so their description will be omitted.

[0126] According to the inertial sensor device 1 of the third embodiment described above, if any of the measurement data DO based on the output signals of each of the inertial sensors 10 of IMU2a to 2g is abnormal, IMU2a performs synthesis processing without using the abnormal data, thereby suppressing a decrease in the calculation accuracy of the synthesis processing. Furthermore, according to the inertial sensor device 1 of the third embodiment, the host data Vice 3 can estimate the accuracy of the measurement data DO based on composite number information, and therefore can perform appropriate processing based on the measurement data DO.

[0127] Furthermore, the inertial sensor device 1 of the third embodiment provides the same effects as the inertial sensor device 1 of the first or second embodiment.

[0128] 4. Variations The present invention is not limited to this embodiment, and various modifications can be implemented within the scope of the gist of the present invention.

[0129] For example, in the inertial sensor device 1 of each of the embodiments described above, the number of IMUs connected to the respective communication interface circuits 32 of IMUs 2a, 2b, and 2c is not limited to 0 or 2, but may be 1. Also, one or two IMUs may be connected to the respective communication interface circuits 32 of IMUs 2d, 2e, 2f, and 2g. In other words, the number of IMUs included in the inertial sensor device 1 is not particularly limited.

[0130] The embodiments and variations described above are examples only and are not limiting. For example, each embodiment and each variation can be combined as appropriate.

[0131] The present invention includes configurations substantially identical to those described in the embodiments, for example, configurations with the same function, method, and results, or configurations with the same purpose and effect. Furthermore, the present invention includes configurations in which non-essential parts of the configurations described in the embodiments are replaced. Furthermore, the present invention includes configurations that produce the same effects or achieve the same purpose as those described in the embodiments. Finally, the present invention includes configurations that add known technology to the configurations described in the embodiments.

[0132] The following can be derived from the embodiments and modifications described above.

[0133] One embodiment of an inertial sensor device is: An inertial sensor device having multiple inertial measurement units and connected to an external device, Each of the aforementioned plurality of inertial measurement units is Inertial sensor and, A signal processing unit that processes the output signal of the inertial sensor, The First Communications Department and, It is equipped with a second communications unit, The plurality of inertial measurement units include a first inertial measurement unit, a second inertial measurement unit, a third inertial measurement unit, and a fourth inertial measurement unit. The first communication unit of the first inertial measurement unit and the first communication unit of the second inertial measurement unit are connected to the second communication unit of the third inertial measurement unit. The first communication unit of the third inertial measurement unit is connected to the second communication unit of the fourth inertial measurement unit. The first communication unit of the fourth inertial measurement unit is connected to the external device, The first communication unit of the first inertial measurement unit transmits the first signal output from the signal processing unit of the first inertial measurement unit to the second communication unit of the third inertial measurement unit. The first communication unit of the second inertial measurement unit transmits the second signal output from the signal processing unit of the second inertial measurement unit to the second communication unit of the third inertial measurement unit. The signal processing unit of the third inertial measurement unit performs calculations on the first signal, the second signal, and the third signal which is the output signal of the inertial sensor of the third inertial measurement unit, and outputs a fourth signal. The first communication unit of the third inertial measurement unit transmits the fourth signal to the fourth inertial measurement unit Transmit to the second communication unit of the net, The signal processing unit of the fourth inertial measurement unit performs calculations on the fourth signal and the fifth signal, which is the output signal of the inertial sensor of the fourth inertial measurement unit, and outputs a sixth signal. The first communication unit of the fourth inertial measurement unit transmits the sixth signal to the external device.

[0134] With this inertial sensor device, the fourth inertial measurement unit performs calculations using the first, second, third, and fifth signals, which are based on the output signals of the inertial sensors of the first, second, third, and fourth inertial measurement units, respectively, thereby improving calculation accuracy. Furthermore, with this inertial sensor device, since the first and second inertial measurement units are connected in parallel to the third inertial measurement unit, the increase in calculation processing time and communication time is suppressed compared to the case where the first and second inertial measurement units are connected in series to the third inertial measurement unit. Furthermore, in the case where the first and second inertial measurement units are connected in series to the third inertial measurement unit, if the second inertial measurement unit fails, both the first and second inertial measurement units become unusable. In contrast, with this inertial sensor device, if either the first or second inertial measurement unit fails, only the first or second inertial measurement unit becomes unusable, thus suppressing a decrease in calculation accuracy.

[0135] In one embodiment of the inertial sensor device, Each of the plurality of inertial measurement units includes a control unit, The control unit of the first inertial measurement unit generates first connection information that can identify the number of inertial measurement units connected to the second communication unit of the first inertial measurement unit, The first communication unit of the first inertial measurement unit transmits the first connection information to the second communication unit of the third inertial measurement unit. The control unit of the second inertial measurement unit generates second connection information that can identify the number of inertial measurement units connected to the second communication unit of the second inertial measurement unit, The first communication unit of the second inertial measurement unit transmits the second connection information to the second communication unit of the third inertial measurement unit. The control unit of the third inertial measurement unit generates third connection information that can identify the number of inertial measurement units connected to the second communication unit of the third inertial measurement unit, based on the first connection information and the second connection information. The first communication unit of the third inertial measurement unit transmits the third connection information to the second communication unit of the fourth inertial measurement unit. The control unit of the fourth inertial measurement unit generates fourth connection information that can identify the number of inertial measurement units connected to the second communication unit of the fourth inertial measurement unit, based on the third connection information. The signal processing unit of the fourth inertial measurement unit may perform the calculation based on the fourth connection information.

[0136] In this inertial sensor device, the first and second inertial measurement units transmit first and second connection information to the third inertial measurement unit, respectively. The third inertial measurement unit then transmits third connection information, generated based on the first and second connection information, to the fourth inertial measurement unit. The fourth inertial measurement unit then recognizes the number of inertial measurement units connected to an external device based on the third connection information, generates fourth connection information, and performs appropriate calculations according to the fourth connection information. Furthermore, in this inertial sensor device, the fourth connection information is obtained through communication between the first, second, third, and fourth inertial measurement units, eliminating the need to pre-store the fourth connection information in the non-volatile memory of the fourth inertial measurement unit. Therefore, this inertial sensor device According to this, production costs can be reduced, and high scalability can be achieved because the number of inertial measurement units can be easily increased or decreased.

[0137] In one embodiment of the inertial sensor device, The first communication unit of the fourth inertial measurement unit may transmit the fourth connection information to the external device.

[0138] With this inertial sensor device, the external device can recognize the number of inertial measurement units connected to it based on the fourth connection information, and therefore can process the sixth signal appropriately according to the number of connections. Furthermore, with this inertial sensor device, there is no need to pre-store the fourth connection information in the non-volatile memory of the external device, thus increasing the flexibility and expandability of the system configuration.

[0139] In one embodiment of the inertial sensor device, When the first communication unit of the fourth inertial measurement unit receives an initial setup command from the external device, The second communication unit of the fourth inertial measurement unit transmits a command to the first communication unit of the third inertial measurement unit to initialize the third inertial measurement unit. The second communication unit of the third inertial measurement unit may send a command to the first communication unit of the first inertial measurement unit to initialize the first inertial measurement unit, and a command to the first communication unit of the second inertial measurement unit to initialize the second inertial measurement unit.

[0140] In this inertial sensor device, the initial settings of the first, second, third, and fourth inertial measurement units are performed by initial setting commands transmitted from an external device. Therefore, it is not necessary to pre-store initial setting information in the non-volatile memory of the first, second, third, and fourth inertial measurement units. Consequently, this inertial sensor device can reduce production costs and increase the flexibility and expandability of system construction.

[0141] In one embodiment of the inertial sensor device, The signal processing unit of the third inertial measurement unit is: A predetermined process is performed on the third signal to generate a seventh signal. Determine whether the first signal, the second signal, and the seventh signal are normal or abnormal. The signal that is determined to be normal among the first signal, the second signal, and the seventh signal is used for synthesis processing and the fourth signal is output. The first communication unit of the third inertial measurement unit may transmit, along with the fourth signal, composite number information that can identify the number of signals used in the composite processing to the second communication unit of the fourth inertial measurement unit.

[0142] This inertial sensor device reduces the noise component in the fourth signal by combining the first, second, and seventh signals. If any of the first, second, or seventh signals are abnormal, the combining process is performed without using the abnormal signal, thus suppressing a decrease in the calculation accuracy of the combining process. Furthermore, when the first and second inertial measurement units are connected in series to the third inertial measurement unit, if the second inertial measurement unit fails, both the first and second inertial measurement units become unusable, significantly reducing the noise component reduction effect of the combining process. In contrast, with this inertial sensor device, if either the first or second inertial measurement unit fails, only the first or second inertial measurement unit becomes unusable, thus suppressing a decrease in the noise component reduction effect of the combining process. This can reduce the decrease in the reduction effect.

[0143] Another embodiment of an inertial sensor device is: An inertial sensor device having multiple inertial measurement units and connected to an external device, Each of the aforementioned plurality of inertial measurement units is Inertial sensor and, A signal processing unit that processes the output signal of the inertial sensor, The First Communications Department and, It is equipped with a second communications unit, The plurality of inertial measurement units include a first inertial measurement unit, a second inertial measurement unit, and a third inertial measurement unit. The first communication unit of the first inertial measurement unit and the first communication unit of the second inertial measurement unit are connected to the second communication unit of the third inertial measurement unit. The first communication unit of the third inertial measurement unit is connected to the external device, The first communication unit of the first inertial measurement unit transmits the first signal output from the signal processing unit of the first inertial measurement unit to the second communication unit of the third inertial measurement unit. The first communication unit of the second inertial measurement unit transmits the second signal output from the signal processing unit of the second inertial measurement unit to the second communication unit of the third inertial measurement unit. The signal processing unit of the third inertial measurement unit performs calculations on the first signal, the second signal, and the third signal which is the output signal of the inertial sensor of the third inertial measurement unit, and outputs a fourth signal. The first communication unit of the third inertial measurement unit transmits the fourth signal to the external device.

[0144] With this inertial sensor device, the third inertial measurement unit performs calculations using the first, second, and third signals based on the output signals of the inertial sensors of the first, second, and third inertial measurement units, respectively, thereby improving calculation accuracy. Furthermore, with this inertial sensor device, since the first and second inertial measurement units are connected in parallel to the third inertial measurement unit, the increase in calculation processing time and communication time is suppressed compared to the case where the first and second inertial measurement units are connected in series to the third inertial measurement unit. In addition, when the first and second inertial measurement units are connected in series to the third inertial measurement unit, if the second inertial measurement unit fails, both the first and second inertial measurement units become unusable. However, with this inertial sensor device, if either the first or second inertial measurement unit fails, only the first or second inertial measurement unit becomes unusable, thus suppressing a decrease in calculation accuracy.

[0145] In one embodiment of the inertial sensor device, Each of the plurality of inertial measurement units includes a control unit, The control unit of the first inertial measurement unit generates first connection information that can identify the number of inertial measurement units connected to the second communication unit of the first inertial measurement unit, The first communication unit of the first inertial measurement unit transmits the first connection information to the second communication unit of the third inertial measurement unit. The control unit of the second inertial measurement unit generates second connection information that can identify the number of inertial measurement units connected to the second communication unit of the second inertial measurement unit, The first communication unit of the second inertial measurement unit transmits the second connection information to the second communication unit of the third inertial measurement unit. The control unit of the third inertial measurement unit generates third connection information that can identify the number of inertial measurement units connected to the external device, based on the first connection information and the second connection information. The signal processing unit of the third inertial measurement unit may perform the calculation based on the third connection information.

[0146] In this inertial sensor device, the first and second inertial measurement units transmit first and second connection information to the third inertial measurement unit, respectively. The third inertial measurement unit then recognizes the number of inertial measurement units connected to an external device based on the first and second connection information, generates third connection information, and performs appropriate calculations according to the third connection information. Furthermore, since the third connection information is obtained through communication between the first, second, and third inertial measurement units in this inertial sensor device, there is no need to pre-store the third connection information in the non-volatile memory of the third inertial measurement unit. Therefore, this inertial sensor device can reduce production costs and achieve high expandability because it is easy to increase or decrease the number of inertial measurement units.

[0147] In one embodiment of the inertial sensor device, The first communication unit of the third inertial measurement unit may transmit the third connection information to the external device.

[0148] With this inertial sensor device, the external device can recognize the number of inertial measurement units connected to it based on the third connection information, and therefore can process the fourth signal appropriately according to the number of connections. Furthermore, with this inertial sensor device, there is no need to pre-store the third connection information in the non-volatile memory of the external device, thus increasing the flexibility and expandability of the system configuration.

[0149] In one embodiment of the inertial sensor device, When the first communication unit of the third inertial measurement unit receives an initial setup command from the external device, The second communication unit of the third inertial measurement unit may send a command to the first communication unit of the first inertial measurement unit to initialize the first inertial measurement unit, and a command to the first communication unit of the second inertial measurement unit to initialize the second inertial measurement unit.

[0150] In this inertial sensor device, the initial settings of the first, second, and third inertial measurement units are performed by initial setting commands transmitted from an external device. Therefore, it is not necessary to pre-store initial setting information in the non-volatile memory of the first, second, and third inertial measurement units. Consequently, this inertial sensor device can reduce production costs and increase the flexibility and expandability of system construction.

[0151] In one embodiment of the inertial sensor device, The signal processing unit of the third inertial measurement unit is: A predetermined process is performed on the third signal to generate a fifth signal. Determine whether the first signal, the second signal, and the fifth signal are normal or abnormal. The signal that is determined to be normal among the first signal, the second signal, and the fifth signal is used for synthesis processing and the fourth signal is output. The first communication unit of the third inertial measurement unit may transmit, along with the fourth signal, composite number information that can identify the number of signals used in the composite processing to the external device.

[0152] According to this inertial sensor device, the noise component contained in the fourth signal can be reduced by combining the first signal, the second signal, and the fifth signal. If any of the numbers is abnormal, the synthesis process is performed without using the abnormal signal, thus suppressing a decrease in the calculation accuracy of the synthesis process. Furthermore, when the first and second inertial measurement units are connected in series to the third inertial measurement unit, if the second inertial measurement unit fails, both the first and second inertial measurement units become unusable, significantly reducing the noise component reduction effect of the synthesis process. In contrast, with this inertial sensor device, if either the first or second inertial measurement unit fails, only the first or second inertial measurement unit becomes unusable, thus minimizing the decrease in the noise component reduction effect of the synthesis process. Moreover, with this inertial sensor device, external devices can estimate the accuracy of the measurement data based on the synthesis number information, enabling them to perform appropriate processing based on the measurement data. [Explanation of Symbols]

[0153] 1...Inertial sensor device, 2a~2g...Inertial measurement unit (IMU), 3...Host device, 10...Inertial sensor, 20...Signal processing unit, 21...Correction processing unit, 22...Matching processing unit, 23...Synthesis processing unit, 24...Anomaly detection unit, 31...Communication interface circuit, 32...Communication interface circuit, 40...Control unit, 50...Storage unit, 51...Register, 52...Non-volatile memory, 60...Oscillation circuit, 70...Switch

Claims

1. An inertial sensor device having multiple inertial measurement units and connected to an external device, Each of the aforementioned plurality of inertial measurement units is Inertial sensor and, A signal processing unit that processes the output signal of the inertial sensor, First Communications Department and, It is equipped with a second communications unit, The plurality of inertial measurement units include a first inertial measurement unit, a second inertial measurement unit, a third inertial measurement unit, and a fourth inertial measurement unit. The first communication unit of the first inertial measurement unit and the first communication unit of the second inertial measurement unit are connected to the second communication unit of the third inertial measurement unit. The first communication unit of the third inertial measurement unit is connected to the second communication unit of the fourth inertial measurement unit. The first communication unit of the fourth inertial measurement unit is connected to the external device, The first communication unit of the first inertial measurement unit transmits the first signal output from the signal processing unit of the first inertial measurement unit to the second communication unit of the third inertial measurement unit. The first communication unit of the second inertial measurement unit transmits the second signal output from the signal processing unit of the second inertial measurement unit to the second communication unit of the third inertial measurement unit. The signal processing unit of the third inertial measurement unit performs calculations on the first signal, the second signal, and the third signal which is the output signal of the inertial sensor of the third inertial measurement unit, and outputs a fourth signal. The first communication unit of the third inertial measurement unit transmits the fourth signal to the second communication unit of the fourth inertial measurement unit. The signal processing unit of the fourth inertial measurement unit performs calculations on the fourth signal and the fifth signal, which is the output signal of the inertial sensor of the fourth inertial measurement unit, and outputs a sixth signal. The first communication unit of the fourth inertial measurement unit is an inertial sensor device that transmits the sixth signal to the external device.

2. In claim 1, Each of the plurality of inertial measurement units includes a control unit, The control unit of the first inertial measurement unit generates first connection information that can identify the number of inertial measurement units connected to the second communication unit of the first inertial measurement unit, The first communication unit of the first inertial measurement unit transmits the first connection information to the second communication unit of the third inertial measurement unit. The control unit of the second inertial measurement unit generates second connection information that can identify the number of inertial measurement units connected to the second communication unit of the second inertial measurement unit, The first communication unit of the second inertial measurement unit transmits the second connection information to the second communication unit of the third inertial measurement unit. The control unit of the third inertial measurement unit generates third connection information that can identify the number of inertial measurement units connected to the second communication unit of the third inertial measurement unit, based on the first connection information and the second connection information. The first communication unit of the third inertial measurement unit transmits the third connection information to the second communication unit of the fourth inertial measurement unit. The control unit of the fourth inertial measurement unit generates fourth connection information that can identify the number of inertial measurement units connected to the second communication unit of the fourth inertial measurement unit, based on the third connection information. The signal processing unit of the fourth inertial measurement unit is an inertial sensor device that performs the calculation based on the fourth connection information.

3. In claim 2, The first communication unit of the fourth inertial measurement unit is an inertial sensor device that transmits the fourth connection information to the external device.

4. In claim 1, When the first communication unit of the fourth inertial measurement unit receives an initial setup command from the external device, The second communication unit of the fourth inertial measurement unit transmits a command to the first communication unit of the third inertial measurement unit to initialize the third inertial measurement unit. An inertial sensor device wherein the second communication unit of the third inertial measurement unit transmits a command to the first communication unit of the first inertial measurement unit to initialize the first inertial measurement unit, and transmits a command to the first communication unit of the second inertial measurement unit to initialize the second inertial measurement unit.

5. In claim 1, The signal processing unit of the third inertial measurement unit is: A predetermined process is performed on the third signal to generate a seventh signal. Determine whether the first signal, the second signal, and the seventh signal are normal or abnormal. The signal that is determined to be normal among the first signal, the second signal, and the seventh signal is used for synthesis processing and the fourth signal is output. An inertial sensor device wherein the first communication unit of the third inertial measurement unit transmits, along with the fourth signal, composite number information that can identify the number of signals used in the composite processing to the second communication unit of the fourth inertial measurement unit.

6. An inertial sensor device having multiple inertial measurement units and connected to an external device, Each of the aforementioned plurality of inertial measurement units is Inertial sensor and, A signal processing unit that processes the output signal of the inertial sensor, First Communications Department and, It is equipped with a second communications unit, The plurality of inertial measurement units include a first inertial measurement unit, a second inertial measurement unit, and a third inertial measurement unit. The first communication unit of the first inertial measurement unit and the first communication unit of the second inertial measurement unit are connected to the second communication unit of the third inertial measurement unit. The first communication unit of the third inertial measurement unit is connected to the external device, The first communication unit of the first inertial measurement unit transmits the first signal output from the signal processing unit of the first inertial measurement unit to the second communication unit of the third inertial measurement unit. The first communication unit of the second inertial measurement unit transmits the second signal output from the signal processing unit of the second inertial measurement unit to the second communication unit of the third inertial measurement unit. The signal processing unit of the third inertial measurement unit performs calculations on the first signal, the second signal, and the third signal which is the output signal of the inertial sensor of the third inertial measurement unit, and outputs a fourth signal. The first communication unit of the third inertial measurement unit is an inertial sensor device that transmits the fourth signal to the external device.

7. In claim 6, Each of the plurality of inertial measurement units includes a control unit, The control unit of the first inertial measurement unit generates first connection information that can identify the number of inertial measurement units connected to the second communication unit of the first inertial measurement unit, The first communication unit of the first inertial measurement unit transmits the first connection information to the second communication unit of the third inertial measurement unit. The control unit of the second inertial measurement unit generates second connection information that can identify the number of inertial measurement units connected to the second communication unit of the second inertial measurement unit, The first communication unit of the second inertial measurement unit transmits the second connection information to the second communication unit of the third inertial measurement unit. The control unit of the third inertial measurement unit generates third connection information that can identify the number of inertial measurement units connected to the external device, based on the first connection information and the second connection information. The signal processing unit of the third inertial measurement unit is an inertial sensor device that performs the calculation based on the third connection information.

8. In claim 7, The first communication unit of the third inertial measurement unit is an inertial sensor device that transmits the third connection information to the external device.

9. In claim 6, When the first communication unit of the third inertial measurement unit receives an initial setting command from the external device, An inertial sensor device wherein the second communication unit of the third inertial measurement unit transmits a command to the first communication unit of the first inertial measurement unit to initialize the first inertial measurement unit, and transmits a command to the first communication unit of the second inertial measurement unit to initialize the second inertial measurement unit.

10. In claim 6, The signal processing unit of the third inertial measurement unit is: A predetermined process is performed on the third signal to generate a fifth signal. Determine whether the first signal, the second signal, and the fifth signal are normal or abnormal. The signal that is determined to be normal among the first signal, the second signal, and the fifth signal is used for synthesis processing and the fourth signal is output. The inertial sensor device wherein the first communication unit of the third inertial measurement unit transmits, along with the fourth signal, composite number information that can identify the number of signals used in the composite processing to the external device.

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