Sensor Device

Abstract

To provide a sensor device capable of appropriately calculating detection data.SOLUTION: A sensor device 1 comprises a plurality of sensor units 21 and 22, a control unit 15 and a plurality of communication paths 31 and 32. The sensor units 21 and 22 have sensor elements 211, 212, 221 and 222 for detecting change in a physical quantity and communication circuits 215 and 225 for transmitting a response signal according to a detection value of the sensor elements 211, 212, 221 and 222. The control unit 15 includes communication circuits 16 and 17 for transmitting a request signal requesting transmission of a response signal and receiving the response signal, and an arithmetic processing unit 18 for calculating torque data according to the response signal. The plurality of communication paths 31 and 32 individually connects the sensor units 21 and 22 to the control unit 15. The arithmetic processing unit 18 calculates torque data using the response signal simultaneously acquired from the plurality of sensor units 21 and 22. Thus, torque data can be appropriately calculated.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a sensor device. [Background technology]

[0002] Conventionally, there is known a sensor device in which communication is performed between a sensor and a controller. For example, in Patent Document 1, the sensor is configured to transmit a response signal in response to a request signal from a receiving circuit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US Patent Application Publication No. 2013 / 0343472 Summary of the Invention [Problem to be solved by the invention]

[0004] In a system such as that described in Patent Document 1, which has only one transmission path and transmits information from a single sensor element per response signal to a single request signal, when information from multiple sensor elements is transmitted and used for calculation, the calculation period using information from multiple elements is delayed compared to the signal reception period.

[0005] The present invention has been made in view of the above-mentioned problems, and has an object to provide a sensor device capable of appropriately calculating detection data. [Means for solving the problem]

[0006] The sensor device of the present invention includes a plurality of sensor units (21, 22, 23, 24), a control unit (15), and a plurality of communication paths (31, 32). The sensor units include sensor elements (211, 212, 221, 222) that detect a change in a physical quantity, and sensor-side communication circuits (215, 225) that transmit a signal including one response signal corresponding to a detection value of the sensor element in response to one request signal.

[0007] The arithmetic processing unit has a control unit side communication circuit (16, 17) that transmits a request signal and receives a response signal, and an arithmetic processing unit (18) that calculates detection data according to the response signal. The communication path connects the sensor units to the control unit individually. The arithmetic processing unit calculates the detection data using the response signals acquired in parallel from the multiple sensor units. Each sensor unit has k (k is an integer of 2 or more) sensor elements, and transmits, as response signals, signals corresponding to detection values ​​of the first to kth sensor elements in a predetermined order. In the first aspect, the calculation processing unit calculates detection data based on response signals currently acquired from the multiple sensor units, and calculates corrected detection data using the detection data from the (k-1)th time before to the current time. In the second aspect, data calculated using response signals from the (k-1)th time before to the present time in the same sensor unit is defined as intra-sensor detection data, and the calculation processing unit calculates the detection data using the current value of the intra-sensor detection data related to multiple sensor units. This makes it possible to appropriately calculate the detection data. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic configuration diagram showing a steering system according to a first embodiment. [Diagram 2] FIG. 1 is a block diagram showing a sensor device according to a first embodiment. [Diagram 3] 5 is a time chart illustrating calculation of torque data according to the first embodiment. [Figure 4] FIG. 4 is an explanatory diagram illustrating an output signal of the sensor element according to the first embodiment. [Diagram 5] FIG. 4 is an explanatory diagram illustrating torque data according to the first embodiment. [Figure 6] 5 is a time chart illustrating the calculation of corrected torque data according to the first embodiment. [Figure 7] 5 is a time chart showing a case where an abnormality occurs in one sensor element according to the first embodiment. [Figure 8] 5 is a time chart illustrating torque data when an abnormality occurs in one sensor unit according to the first embodiment. [Figure 9] 5 is a flowchart illustrating a torque calculation process according to the first embodiment. [Figure 10] FIG. 4 is an explanatory diagram showing frame data of a response signal according to the first embodiment. [Figure 11] FIG. 4 is an explanatory diagram showing check data of a response signal according to the first embodiment. [Figure 12] 6 is a time chart illustrating calculation of torque data when one system has an abnormality according to the second embodiment. [Figure 13] FIG. 13(a) is a diagram showing torque data before correction according to the second embodiment, and (b) is a diagram showing torque data after correction according to the second embodiment. [Figure 14] 13 is a time chart illustrating calculation of torque data when one system has an abnormality according to the third embodiment. [Figure 15] 13 is a time chart illustrating calculation of torque data when one system has an abnormality according to the fourth embodiment. [Figure 16] 13 is a time chart illustrating calculation of torque data according to the fifth embodiment. [Figure 17] FIG. 13 is a block diagram showing a sensor device according to a sixth embodiment. [Figure 18] FIG. 1 is a block diagram showing a sensor device according to a reference example. [Figure 19] 6 is a time chart illustrating calculation of torque data according to a reference example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A sensor device according to the present invention will be described below with reference to the drawings. In the following, in a number of embodiments, substantially the same components are designated by the same reference numerals, and description thereof will be omitted.

[0010] (First embodiment) A first embodiment is shown in Figures 1 to 11. As shown in Figure 1, a sensor device 1 includes a torque sensor 20 and an ECU 10, and is applied to an electric power steering device 8 as a steering device for assisting the steering operation of a vehicle.

[0011] 1 shows the overall configuration of a steering system 90 including an electric power steering device 8. The steering system 90 includes a steering wheel 91, which is a steering member, a steering shaft 92, a pinion gear 96, a rack shaft 97, wheels 98, the electric power steering device 8, and the like.

[0012] The steering wheel 91 is connected to a steering shaft 92. The steering shaft 92 is provided with a torque sensor 20 that detects steering torque. The torque sensor 20 is connected to the ECU 10 via a harness 106 and a connector 105. The harness 106 includes communication paths 31, 32 (see FIG. 2). A pinion gear 96 is provided at the tip of the steering shaft 92. The pinion gear 96 meshes with a rack shaft 97. A pair of wheels 98 are connected to both ends of the rack shaft 97 via tie rods or the like.

[0013] When a driver turns a steering wheel 91, a steering shaft 92 connected to the steering wheel 91 rotates. The rotational motion of the steering shaft 92 is converted into linear motion of a rack shaft 97 by a pinion gear 96. A pair of wheels 98 are steered to an angle according to the amount of displacement of the rack shaft 97.

[0014] The electric power steering device 8 includes an ECU 10, a torque sensor 20, a motor 80, and a reduction gear 89 as a power transmission unit that reduces the speed of rotation of the motor 80 and transmits the reduced speed to a rack shaft 97. The electric power steering device 8 of this embodiment is a so-called "rack assist type", but may be a so-called "column assist type" in which the rotation of the motor 80 is transmitted to a steering shaft 92.

[0015] The motor 80 is, for example, a three-phase brushless motor that outputs a part or all of the torque required for steering. The motor 80 is driven by power supplied from a battery (not shown) to rotate the reduction gear 89 forward and reverse.

[0016] The ECU 10 is a so-called "mechanically and electrically integrated" type that is provided integrally on one side of the motor 80 in the axial direction, but the motor 80 and the control unit 15 may be provided separately. The control unit 15 is disposed substantially coaxially with the motor shaft on the opposite side to the output shaft of the motor 80. By adopting a mechano-electrically integrated type, the control unit 15 and the motor 80 can be efficiently disposed in a vehicle with limited mounting space.

[0017] The ECU 10 has a control unit 15 (see FIG. 2) mainly composed of a microcomputer, etc., and is internally provided with a CPU, ROM, RAM, I / O, and bus lines connecting these components, all of which are not shown. Each process in the control unit 15 may be software processing in which the CPU executes a program stored in advance in a substantial memory device (i.e., a readable non-transitory tangible storage medium) such as a ROM, or may be hardware processing in which a dedicated electronic circuit is used.

[0018] 2, the control unit 15 has communication circuits 16 and 17, an arithmetic processing unit 18, etc. The first communication circuit 16 is connected to the first sensor unit 21 via a first communication path 31. The first communication circuit 16 transmits a request signal to the first sensor unit 21, and receives a response signal from the first sensor unit 21 in response to the request signal.

[0019] The second communication circuit 17 is connected to the second sensor unit 22 via the second communication path 32. The second communication circuit 17 transmits a request signal to the second sensor unit 22, and receives a response signal corresponding to the request signal from the second sensor unit 22. Hereinafter, the subscript "1" will be added to signals transmitted and received between the first communication circuit 16 and the first sensor unit 21, and the subscript "2" will be added to signals transmitted and received between the second communication circuit 17 and the second sensor unit 22, as appropriate.

[0020] The calculation processing unit 18 calculates torque data relating to the torque applied to the steering shaft 92 based on the response signals received from the sensor units 21 and 22.

[0021] The torque sensor 20 has a first sensor section 21 and a second sensor section 22. Hereinafter, the configuration related to the first sensor section 21 will be referred to as the first system, and the configuration related to the second sensor section 22 will be referred to as the second system. The first sensor section 21 has two sensor elements 211 and 212, and a communication circuit 215. The second sensor section 22 has two sensor elements 221 and 222, and a communication circuit 225. Hereinafter, the sensor element 211 of the first sensor section 21 will be referred to as "1A", the sensor element 212 will be referred to as "1B", the sensor element 221 of the second sensor section 22 will be referred to as "2A", and the sensor element 222 will be referred to as "2B".

[0022] The sensor elements 211, 212, 221, and 222 detect the steering torque applied to the steering shaft 92. More specifically, the sensor elements 211, 212, 221, and 222 are Hall elements that detect a change in the magnetic field of a sensor magnet that is displaced in accordance with the amount of twisting displacement of a torsion bar (not shown) provided on the steering shaft 92.

[0023] The sensor device 1 is applied to an electric power steering device 8. The electric power steering device 8 is responsible for the "turning" function of the vehicle, and is required to have a highly safe system that provides unstoppable assistance. In order to realize a highly safe system, the torque sensor 20 is provided with multiple sensor elements 211, 212, 221, and 222 for redundancy.

[0024] Here, data communication according to a reference example is shown in Fig. 18 and Fig. 19. As shown in Fig. 18, a sensor device 700 shown in the reference example includes a control unit 715 and a torque sensor 720. The control unit 715 has a communication circuit 16 and an arithmetic processing unit 18. The torque sensor 720 has sensor elements 211, 212, and a communication circuit 215.

[0025] The sensor device 700 has one communication path 731, and transmits information from one sensor element in response to one request signal. As shown in Fig. 19, when information from the sensor elements 211 and 212 is transmitted alternately and torque data is calculated from the information from the two sensor elements 211 and 212, the torque calculation is delayed compared to the calculation cycle of the communication circuit 16. If the real-time nature is reduced due to the calculation delay, this may affect the steering feel.

[0026] In this embodiment, the control unit 15 and the torque sensor 20 are connected via communication paths 31 and 32. Therefore, data can be acquired simultaneously from the first sensor unit 21 and the second sensor unit 22, and torque calculation can be performed using a plurality of response signals while ensuring real-time performance.

[0027] 3, in response to a request signal transmitted from the first communication path 31 at time x10, data of sensor element 1A is transmitted from the first sensor unit 21 to the control unit 15. In addition, in response to a request signal transmitted from the second communication path 32 at time x10, data of sensor element 2A is transmitted from the second sensor unit 22 to the control unit 15. The calculation processing unit 18 performs torque calculation based on the received data of sensor elements 1A and 2A.

[0028] Moreover, in response to a request signal transmitted from the first communication path 31 at time x11, data of sensor element 1B is transmitted from the first sensor unit 21 to the control unit 15. Moreover, in response to a request signal transmitted from the second communication path 32 at time x11, data of sensor element 2B is transmitted from the second sensor unit 22 to the control unit 15. The calculation processing unit 18 performs torque calculation based on the received data of sensor elements 1B, 2B. Hereinafter, the torque calculation result based on sensor elements 1A, 2A will be referred to as torque data A, and the torque calculation result based on sensor elements 1B, 2B will be referred to as torque data B, as appropriate.

[0029] At time x12, the same processing as at time x10 is performed, and at time x13, the same processing as at time x11 is performed, and so on, alternating between receiving data from sensor elements 1A and 2A and using this data to calculate torque data A, and receiving data from sensor elements 1B and 2B and using this data to calculate torque data B.

[0030] As a result, the calculation period of the communication circuit and the calculation period of the torque data become the same, so that torque calculation can be performed using data from multiple sensor elements without degrading real-time performance. Furthermore, by comparing multiple data, it is possible to detect abnormalities such as voltage fixation. Note that an abnormality in the sensor units 21 and 22 refers to a state in which the control unit 15 cannot obtain a normal detection value, and includes not only an abnormality in the sensor units 21 and 22 themselves, but also an abnormality in the communication paths 31 and 32, etc.

[0031] The output signals of sensor elements 1A, 1B, 2A, and 2B will be described with reference to Fig. 4. In Fig. 4, the horizontal axis represents steering torque, and the vertical axis represents the detected voltages of sensor elements 211, 212, 221, and 222. Within the detectable range, as shown by the solid line, the detected voltages of sensor elements 1A and 2B decrease as the torque increases. Also, within the detectable range, as shown by the dashed line, the detected voltages of sensor elements 1B and 2A increase as the torque increases. Blocks showing response signals in Fig. 3 and other figures are also indicated with the same line type.

[0032] In this embodiment, the signals of sensor elements 1A and 2A, which have the same characteristics but opposite outputs, are acquired at the same timing, and the signals of sensor elements 1B and 2B are acquired at the same timing. This makes it easier to detect abnormalities such as sticking, compared to when signals acquired at the same timing have the same increase and decrease characteristics.

[0033] In FIG. 5, the horizontal axis represents the steering torque, and the vertical axis represents the torque data calculation value. As shown in FIG. 5, when the torque data A and B are used alternately, there is a risk of an output error occurring due to variations in output characteristics. In this embodiment, the output error is corrected by averaging the current value and the previous value of the torque data as shown in FIG. 6. Hereinafter, the torque data obtained by averaging the current value and the previous value is appropriately set as the corrected torque data. Note that various calculations may be performed using the torque data of FIG. 3 without performing the correction as shown in FIG. 6. In FIG. 6, the common time axis is the horizontal axis, and from the top, the request signal of the first system, the response signal of the first system, the request signal of the second system, the response signal of the second system, the torque data, and the corrected torque data are shown. The same applies to the time charts according to other embodiments. Also, FIG. 3 is similar except that the corrected torque data is omitted.

[0034] Fig. 7 shows a case where an abnormality occurs in one sensor element. In Fig. 7, an abnormality occurs in the response signal of sensor element 1B, which is shown by the matte finish. The corrected torque data calculated from the occurrence of the abnormality to the time xe when the abnormality is detected is averaged with normal torque data A, so that the effect of the abnormality can be mitigated compared to the case where torque correction is not performed.

[0035] As shown in Fig. 8, when an abnormality occurs in the first sensor unit 21, data from the sensor elements 2A and 2B transmitted alternately from the second sensor unit 22 is used to calculate torque data using the average value of the current value and the previous value. As a result, even if an abnormality occurs in one of the sensor units, the torque calculation period is maintained, so that torque calculation using the detection values ​​of the multiple sensor elements can be continued without deteriorating real-time performance. In Fig. 8 etc., the response signal related to the abnormal first sensor unit 21 is shown by a matte finish.

[0036] The torque calculation process of this embodiment will be described based on the flowchart of FIG. 9. This process is executed in a predetermined cycle by the control unit 15. Hereinafter, the "step" such as step S101 will be omitted and simply written as the symbol "S". In addition, the current value will be subscripted with (n), the previous value with (n-1), and the value two times before with (n-2). In the explanation of the flowchart, as an example, the data acquired this time is the data of sensor elements 1A and 2A, and the data acquired last time is the data of sensor elements 1B and 2B. Note that when the data acquired this time are sensor elements 1B and 2B, 1A and 1B, and 2A and 2B may be appropriately replaced.

[0037] In S101, the control unit 15 transmits a request signal to the sensor units 21 and 22. In S102, the control unit 15 receives, from the sensor units 21 and 22, a response signal transmitted in response to the request signal.

[0038] In S103, the calculation processing unit 18 judges whether the acquired response signals of both systems are normal or not. In this embodiment, the detection voltages of the sensor elements 1A and 2A acquired at the same timing have the same characteristics but opposite outputs, and the sum of the detection voltages of the sensor elements 1A and 2A when both are normal is a predetermined value, so that the sum of the detection voltages of the sensor elements 1A and 2A is set as the abnormality determination value X (see formula (1)). In the formula, the detection voltage detected from the first sensor unit 21 is V1, and the detection voltage detected from the second sensor unit 22 is V2.

[0039] X = V1(n) + V2(n) (1)

[0040] The calculation processing unit 18 judges whether or not both systems are normal based on the abnormality judgment value X. If the abnormality judgment value X is within a predetermined range including the normal value Xt, it is assumed that the abnormality judgment value X and the normal value Xt match, and it is judged that both systems are normal. If it is judged that both systems are normal (S103: YES), that is, if the abnormality judgment value X and the normal value Xt match, the process proceeds to S104. If it is judged that an abnormality may have occurred in at least one system (S103: NO), that is, if the abnormality judgment value X and the normal value Xt do not match, the process proceeds to S106.

[0041] Also, in S103, data interruption may be detected by making the response signal carry frame data as shown in Fig. 10. Furthermore, data abnormality may be detected by making at least one of the request signal and the response signal carry check data such as CRC or parity check as shown in Fig. 11. If it is determined that an abnormality has occurred in at least one of the systems based on the frame data or the check data, a negative determination is made.

[0042] In S104, the calculation processing unit 18 calculates the current value T(n) of the torque data based on the detection values ​​of the sensor elements 1A and 2A (see equation (2)). In S105, the calculation processing unit 18 uses the current value T(n) of the torque data and the previous value T(n-1) (see equation (3)) to calculate corrected torque data Tc(n) (see equation (4)). In the equations, T1 is the torque equivalent of the detected voltage V1, and T2 is the torque equivalent of the detected voltage V2. In the torque conversion, a coefficient according to the output characteristics of the sensor elements 1A, 1B, 2A, and 2B is multiplied.

[0043] T(n)=(T1(n)+T2(n)) / 2 ···(2) T(n-1)=(T1(n-1)+T2(n-1)) / 2 ···(3) Tc(n)=(T(n)+T(n-1)) / 2 ···(4)

[0044] If it is determined that an abnormality has occurred in at least one of the systems (S103: NO), the process proceeds to S106, in which an abnormality determination value Y1 for the first system and an abnormality determination value Y2 for the second system are calculated, and it is determined whether or not a normal system can be identified based on the abnormality determination values ​​Y1 and Y2 (see equations (5) and (6)).

[0045] Y1={(T1(n)+T1(n-2)) / 2}-T1(n-1) ···(5) Y2={(T2(n)+T2(n-2)) / 2}-T2(n-1) ···(6)

[0046] When the torque change rate is considered to be constant, if it is normal, the average value of the torque conversion value based on the detection value of the sensor element 1A in response to the current request signal and the request signal two times before will theoretically match the torque conversion value based on the detection value of the sensor element 1B in response to the previous request signal. Therefore, the abnormality determination values ​​Y1 and Y2 are compared with the determination threshold TH1, and the system in which the abnormality determination values ​​Y1 and Y2 are smaller than the determination threshold TH1 is identified as the normal system. If it is determined that the normal system can be identified (S106: YES), proceed to S107. Hereinafter, the system identified as normal is referred to as the identified system. If it is determined that the normal system cannot be identified (S106: NO), proceed to S109. Note that this step may be omitted after the normal system is identified.

[0047] In S107, the calculation processing unit 18 calculates abnormality determination values ​​Yp, Yq for the system identified as normal in S107 (see equations (7) and (8)), and performs abnormality monitoring on one system based on the abnormality determination values ​​Yp, Yq. The abnormality determination value Yp is the difference between the average value of the current value and the value two times prior, and the previous value. The abnormality determination value Yq is the difference between the average value of the previous value and the value three times prior, and the value two times prior. In equations (7) and (8), the torque conversion value of the normal system is T#. If the first system is normal, #=1, and if the second system is normal, #=2.

[0048] Yp={(T#(n)+T#(n-2)) / 2}-T#(n-1) ···(7) Yq={(T#(n-1)+T#(n-3)) / 2)}-T#(n-2) (8)

[0049] For example, if an abnormality occurs in the first system and the second system is identified as a normal system, one of the abnormality determination values ​​Yp, Yq is calculated based on the average of two values ​​of the sensor element 2A and the sensor element 2B, and the other is calculated based on the average of two values ​​of the sensor element 2B and the sensor element 2A. In this embodiment, if both of the abnormality determination values ​​Yp, Yq are smaller than the determination threshold value TH2, it is determined that the specific system is normal. The determination threshold value TH2 may be equal to or different from the determination threshold value TH1. It is also possible to omit the calculation of the abnormality determination value Yq and perform the determination based only on the abnormality determination value Yp.

[0050] If the specific system is determined to be normal (S107: YES), that is, if the abnormality determination values ​​Yp, Yq are smaller than the determination threshold TH2, the process proceeds to S108. If the specific system is determined to be abnormal (S107: NO), that is, if at least one of the abnormality determination values ​​Yp, Yq is equal to or greater than the determination threshold TH2, the process proceeds to S109.

[0051] In S108, the calculation processing unit 18 calculates the torque data Te(n) based on the detection value of the normal system (see formula (9)). In S109, the calculation processing unit 18 sets the current value T(n) of the torque data as the setting value when the abnormality occurs.

[0052] Te(n)=(T#(n)+T#(n-1)) / 2 ···(9)

[0053] As described above, the sensor device 1 of this embodiment includes a plurality of sensor units 21, 22, a control unit 15, and a plurality of communication paths 31, 32. The sensor units 21, 22 include sensor elements 211, 212, 221, 222 that detect a change in a physical quantity, and communication circuits 215, 225 that transmit one response signal according to the detection value of the sensor elements 211, 212, 221, 222 in response to one request signal.

[0054] The control unit 15 has communication circuits 16 and 17 that transmit a request signal requesting transmission of a response signal and receive the response signal, and an arithmetic processing unit 18 that calculates torque data according to the response signal. A plurality of communication paths 31 and 32 connect the sensor units 21 and 22 to the control unit 15 individually.

[0055] The calculation processing unit 18 calculates torque data using response signals acquired simultaneously from the multiple sensor units 21, 22. Here, "response signals acquired simultaneously" refers to response signals transmitted in response to request signals transmitted at approximately the same timing, and a degree of timing deviation due to individual variations, etc. is permitted. This allows the torque data to be appropriately calculated based on the response signals acquired simultaneously from the multiple sensor units 21, 22.

[0056] The sensor units 21 and 22 each have k (k is an integer equal to or greater than 2) sensor elements. The sensor units 21 and 22 transmit, as response signals, signals corresponding to the detection values ​​of the first to k-th sensor elements in a predetermined order. In this embodiment, since k=2, response signals corresponding to the detection values ​​of two sensor elements are transmitted alternately. In other words, the sensor units are configured such that the detection values ​​of all the sensor elements are transmitted once each in response to k request signals.

[0057] The calculation processing unit 18 calculates torque data based on the response signals currently acquired from the plurality of sensor units 21, 22, and calculates corrected detection data using the detection data from the (k-1)th time before to the current time.

[0058] As a result, it is possible to detect abnormalities in the sensor elements, such as voltage fixation, by calculating torque data using detection values ​​of the multiple sensor elements 211, 212, 221, 222. Also, in a configuration in which one response signal is transmitted in response to one request signal, communication paths 31, 32 are provided for each sensor unit 21, 22, and response signals from the multiple sensor units 21, 22 are combined to calculate torque data, thereby making it possible to shorten the update cycle and improve real-time performance.

[0059] Furthermore, it is possible to reduce errors due to variations in characteristics by calculating torque data using response signals transmitted from the multiple sensor units 21 and 22. Also, if an abnormality occurs in some of the sensor elements, it is possible to reduce the influence of the abnormality on the torque data until the abnormality is detected.

[0060] When an abnormality occurs in some of the sensor units 21, the calculation processing unit 18 calculates torque data using response signals transmitted from the normal sensor units 22 from the (k-1)th time to the current time. This makes it possible to calculate torque data based on detection values ​​of the multiple sensor elements 221, 222 of the normal sensor units 22 even when an abnormality occurs in some of the sensor units 21. In addition, since the calculation cycle can be maintained at the same level as in the normal state, real-time performance can be ensured.

[0061] When k=2 and an abnormality occurs in some of the sensor units 21, response signals corresponding to the sensor elements 221, 222 are alternately transmitted from one normal sensor unit 22. The calculation processing unit 18 uses the most recent four response signals transmitted from one normal sensor unit 22 to monitor the abnormality of that sensor unit 22. This makes it possible to continue monitoring the abnormality of the normal sensor units 22 even if an abnormality occurs in some of the sensor units 21.

[0062] Second embodiment The second embodiment is shown in Figures 12 and 13. In the second to fourth embodiments, the processing when an abnormality occurs in a part of the torque sensor 20 is different from that in the above-mentioned embodiment, and this point will be mainly described. In the second to fourth embodiments, a case where an abnormality occurs in the first system and the second system is normal is taken as an example, and the torque calculation in the normal state is the same as in the first embodiment, but may be the same as in the fifth embodiment described later.

[0063] In this embodiment, it is assumed that an abnormal location in the first system, which is the abnormal system, cannot be identified. When torque data is calculated at the timing when a response signal related to the sensor element 2B is acquired based on the detection values ​​of the sensor elements 2A and 2B of the second sensor unit 22, which is normal, as shown in Fig. 12, the update cycle of the torque data becomes longer compared to, for example, the first embodiment, in which the torque data is updated at the same cycle as the calculation cycle of the communication circuits 16 and 17.

[0064] In Figures 13(a) and 13(b), the horizontal axis represents time and the vertical axis represents torque data, with black circles indicating torque update timing during normal operation and single-system control, and white circles indicating torque update timing that is updated only normally and not during single-system control.

[0065] As shown in Fig. 13(a), the input signal during single-system control, indicated by the dashed line, may be delayed relative to the input signal during normal operation, indicated by the solid line. Therefore, in this embodiment, phase lead compensation is added during single-system control, as indicated by the dashed line in Fig. 13(b). This makes it possible to reduce the effect of calculation delays.

[0066] In this embodiment, when an abnormality occurs in some of the sensor units 21, the calculation processing unit 18 calculates torque data using response signals corresponding to the multiple sensor elements 221, 222 acquired from the normal sensor unit 22. When the calculation period of the torque data when an abnormality occurs is longer than normal, the calculation processing unit 18 performs phase lead compensation as a correction process to correct the calculation delay. The correction process to correct the calculation delay may be a calculation process other than phase lead compensation. This makes it possible to reduce the influence of the calculation delay when an abnormality occurs in some of the sensor units 21. In addition, the same effects as those of the above embodiment are achieved.

[0067] Third embodiment The third embodiment is shown in Fig. 14. In the third and fourth embodiments, an example will be described in which an abnormality occurs in the first system and the abnormal part can be identified. Here, it is assumed that the sensor element 1B is identified as abnormal and the sensor element 1A is normal.

[0068] As shown in FIG. 14, the first sensor unit 21 transmits a response signal corresponding to the detection value of the sensor element 1A, which is normal. The second sensor unit 22 transmits a response signal corresponding to the detection value of the sensor element 2A, which is transmitted simultaneously with the sensor element 1A when normal. That is, even if the sensor element 2B is normal, the second sensor unit 22 changes the signal transmission pattern so that a signal corresponding to the sensor element 2A is transmitted, instead of alternately transmitting signals corresponding to the sensor elements 2A and 2B. The calculation processing unit 18 continues the torque calculation using the sensor elements 1A and 2A.

[0069] Even if an abnormality occurs in a part of the sensor elements 1B, the abnormality can be detected by continuing the calculation using the values ​​of the different sensor parts 21, 22, even if an abnormality such as voltage fixation occurs in one of the sensor parts. Also, the torque update period can be made the same as in the normal state. Furthermore, by performing the torque calculation using the same sensor elements 1A, 2A, it is possible to prevent the variation in torque data caused by the variation in sensor element characteristics.

[0070] In this embodiment, when an abnormality occurs in some of the sensor units 21 and an abnormal system normal element (sensor element 1A in this embodiment) that is a sensor element capable of transmitting a normal detection value can be identified in the abnormal sensor unit 21, the calculation processing unit 18 calculates torque data using a response signal corresponding to the detection value of the abnormal system normal element and a response signal from the normal sensor unit 22. This makes it possible to continue torque calculation while continuing abnormality monitoring even when an abnormality occurs in some of the sensor units 21. In addition, since the calculation cycle can be maintained at the same level as in the normal state, real-time performance can be ensured.

[0071] The normal sensor unit 22 changes the signal transmission pattern so that the response signal corresponding to the detection value of the sensor element 2A, which is transmitted simultaneously with the sensor element 1A, which is a normal element in the abnormal system, continues to be transmitted before the occurrence of the abnormality. This makes it possible to prevent the variation in the torque data caused by the variation of the sensor elements 2A and 2B. Also, the same effects as those of the above embodiment are achieved.

[0072] (Fourth embodiment) A fourth embodiment is shown in Fig. 15. In this embodiment, the first sensor unit 21 transmits an output signal of the sensor element 1A, which is a normal element in the abnormal system, and the second sensor unit 22 transmits the signals of the sensor elements 2A and 2B alternately, as in the normal state. Even with this configuration, it is possible to continue calculations using values ​​from different sensor units, so that it is possible to detect abnormalities such as voltage fixation and to make the torque update period the same as in the normal state. In addition, the same effects as those of the above embodiments are achieved.

[0073] Fifth embodiment The fifth embodiment is shown in Fig. 16. In this embodiment, the calculation processing unit 18 calculates the in-sensor torque data Tm1(n) of the first system using the current value and the previous value of the first sensor unit 21 (see equation (10)). The calculation processing unit 18 also calculates the in-sensor torque data Tm2(n) of the second system using the current value and the previous value of the second sensor unit 22 (see equation (11)). Then, the calculation processing unit 18 calculates the torque data T(n) using the in-sensor torque data Tm1(n) and Tm2(n) (see equation (12)).

[0074] Tm1(n)=(T1(n)+T1(n-1)) / 2 ···(10) Tm2(n)=(T2(n)+T2(n-1)) / 2 ···(11) T(n)=(Tm1(n)+Tm2(n)) / 2 ···(12)

[0075] In this embodiment, if data calculated using response signals from the (k-1)th time before to the present time obtained from the same sensor unit are taken as in-sensor torque data Tm1, Tm2, ​​the calculation processing unit 18 calculates torque data T(n) using the present values ​​of the in-sensor torque data Tm1, Tm2 related to the multiple sensor units 21, 22. Note that the in-sensor torque data Tm1, Tm2 may be values ​​calculated on the sensor units 21, 22 side and transmitted to the control unit 15. Even with this configuration, the same effects as the above embodiment can be achieved.

[0076] Sixth embodiment In the sixth embodiment, the first sensor unit 21 transmits the detection value of the sensor element 1A as a response signal in response to the request signal. The second sensor unit 22 transmits the detection value of the sensor element 2A as a response signal in response to the request signal. The transmission of the response signal and the calculation of the torque data are as shown in FIG.

[0077] It should be noted that the detection value of sensor element 1B may be switched to be transmitted as a response signal at an arbitrary frequency F. When switching to sensor element 1B is not performed, frequency F may be considered as F=0. From the viewpoint of abnormality monitoring, it is preferable that the timing at which the output signal of sensor element 1B is transmitted from first sensor unit 21 and the timing at which the output signal of sensor element 2B is transmitted from second sensor unit 22 are synchronized. Even with this configuration, the same effects as the above embodiment can be achieved.

[0078] Seventh embodiment The seventh embodiment is shown in Fig. 17. As shown in Fig. 17, the first sensor section 23 has one sensor element 211, and the second sensor section 24 has one sensor element 221. The first sensor section 23 transmits the detection value of the sensor element 1A as a response signal in response to a request signal. The second sensor section 24 transmits the detection value of the sensor element 2A as a response signal in response to a request signal. The transmission of the response signal and the calculation of the torque data are as shown in Fig. 14. This allows the configuration to be simplified. Also, the same effects as the above embodiments are achieved.

[0079] In this embodiment, the communication circuits 215 and 225 correspond to the "sensor side communication circuits", the communication circuits 16 and 17 correspond to the "controller side communication circuits", the torque data corresponds to the "detection data", and the torque data in the sensor corresponds to the "sensor side detection data".

[0080] (Other embodiments) In the above embodiment, there are two sensor units, each having one or two sensor elements. In other embodiments, there may be three or more sensor units. Also, each sensor unit may have three or more sensor elements.

[0081] In the above embodiment, the sensor unit is applied to a torque sensor that detects steering torque. In other embodiments, the sensor unit may detect a torque other than steering torque, or may detect a physical quantity other than torque. In the above embodiment, the sensor device is applied to an electric power steering device. In other embodiments, the sensor device may be applied to a device other than an electric power steering device.

[0082] The control unit and the method described in the present disclosure may be realized by a dedicated computer provided by configuring a processor and a memory programmed to execute one or more functions embodied in a computer program. Alternatively, the control unit and the method described in the present disclosure may be realized by a dedicated computer provided by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control unit and the method described in the present disclosure may be realized by one or more dedicated computers configured by a combination of a processor and a memory programmed to execute one or more functions and a processor configured with one or more hardware logic circuits. In addition, the computer program may be stored in a computer-readable non-transient tangible recording medium as instructions executed by a computer. As described above, the present invention is not limited to the above embodiment, and can be implemented in various forms within the scope of the invention. [Explanation of symbols]

[0083] 1. Sensor device 15 Control section 16, 17 Receiving circuit (control unit side communication circuit) 18. Processing unit 20 Torque sensor 21, 22, 23, 24: Sensor section 211, 212, 221, 222... Sensor elements 31, 32... Communication path

Claims

1. a plurality of sensor units (21, 22, 23, 24) each having a sensor element (211, 212, 221, 222) for detecting a change in a physical quantity, and a sensor side communication circuit (215, 225) for transmitting a signal including one response signal corresponding to a detection value of the sensor element in response to one request signal; a control unit (15) having a control unit side communication circuit (16, 17) that transmits the request signal and receives the response signal, and a calculation processing unit (18) that calculates detection data according to the response signal; A plurality of communication paths (31, 32) that individually connect the sensor units to the control unit; Equipped with The calculation processing unit calculates the detection data using the response signals acquired in parallel from the plurality of sensor units, Each of the sensor units has k (k is an integer of 2 or more) sensor elements, and transmits, as the response signal, signals corresponding to detection values ​​of the first to kth sensor elements in a predetermined order; The arithmetic processing unit is Calculating the detection data based on the response signals currently acquired from the plurality of sensor units; The sensor device calculates corrected detection data using the detection data from the (k-1)th time before to the current time.

2. a plurality of sensor units (21, 22, 23, 24) each having a sensor element (211, 212, 221, 222) for detecting a change in a physical quantity, and a sensor side communication circuit (215, 225) for transmitting a signal including one response signal corresponding to a detection value of the sensor element in response to one request signal; a control unit (15) having a control unit side communication circuit (16, 17) that transmits the request signal and receives the response signal, and a calculation processing unit (18) that calculates detection data according to the response signal; A plurality of communication paths (31, 32) that individually connect the sensor units to the control unit; Equipped with The calculation processing unit calculates the detection data using the response signals acquired in parallel from the plurality of sensor units, Each of the sensor units has k (k is an integer of 2 or more) sensor elements, and transmits, as the response signal, signals corresponding to detection values ​​of the first to kth sensor elements in a predetermined order; If the data calculated using the response signals from the (k-1)th time to the current time in the same sensor unit is defined as the in-sensor detection data, The calculation processing unit calculates the detection data using current values ​​of the in-sensor detection data related to the plurality of sensor elements.

3. The sensor device according to claim 1 or 2, wherein when an abnormality occurs in some of the sensor units, the calculation processing unit calculates the detection data using the response signals transmitted from the sensor units that are normal from the (k-1)th time before to the current time.

4. If an abnormality occurs in a part of the sensor, The arithmetic processing unit is calculating the detection data using the response signals corresponding to the plurality of sensor elements acquired from the sensor unit that is normal; 3. The sensor device according to claim 1, wherein when a calculation period of the detection data when an abnormality occurs is longer than that during normal operation, a correction process is performed to correct a delay in the calculation of the detection data.

5. When an abnormality occurs in a part of the sensor units and an abnormal system normal element that is a sensor element capable of transmitting a normal detection value in the sensor unit where the abnormality occurs can be identified, The sensor device according to claim 1 , wherein the calculation processing unit calculates the detection data using the response signal corresponding to the detection value of the normal element of the abnormal system and the response signal from the sensor unit which is normal.

6. The sensor device according to claim 5 , wherein the sensor unit that is normal changes a signal transmission pattern so that the sensor unit continues to transmit a response signal corresponding to the detection value of the sensor element that is transmitted simultaneously with the abnormal system normal element before the occurrence of the abnormality.

7. When k=2 and an abnormality occurs in some of the sensor units, the response signals corresponding to the respective sensor elements are alternately transmitted from one of the sensor units that is normal; The sensor device according to any one of claims 1 to 5, wherein the calculation processing unit uses the most recent four response signals transmitted from one of the sensor units that is normal to monitor the sensor unit for abnormalities.

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