Communication system

Abstract

The present invention relates to a communication system, a receiving section (501) of a microcomputer (70) has a plurality of signal acquisition sections (61A, 61B) and a transmission trigger signal generating section (63B). The plurality of signal acquisition sections (61A, 61B) are connected to sensor elements (31A, 31B) of a corresponding sensor device (301) via independent communication paths (41A, 41B), and acquire sensor values (S1A, S1B) transmitted via the communication paths (41A, 41B) when the communication paths (41A, 41B) become transmittable. The transmission trigger signal generating section (63B) generates a common transmission trigger signal (Trc1) to make the plurality of communication paths (41A, 41B) become capable of simultaneous transmission. In the receiving section (501), the plurality of signal acquisition sections (61A, 61B) can simultaneously acquire a plurality of sensor values (S1A, S1B) by the common transmission trigger signal (Trc1).

Description

[0001] Cross-references to related applications

[0002] This application is based on Japanese Patent Application No. 2021-128131, filed on August 4, 2021, the contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to communication systems. Background Technology

[0004] Previously, communication systems were known where a microcomputer, receiving redundantly detected sensor values ​​from multiple sensors, performed control calculations based on these multiple sensor values. For example, in a communication system applied to electric power steering, the microcomputer calculates the torque value based on multiple sensor values ​​sent from a torque sensor, and then calculates auxiliary quantities based on this torque value. In such communication systems, if the simultaneity of the various sensor values ​​is not maintained, there is a concern that the microcomputer may calculate incorrect torque values ​​or misdetect abnormal sensor values.

[0005] For example, the detection device disclosed in Patent Document 1 generates trigger signals for two microcomputers to request the transmission of sensor values. However, due to timing deviations in the operation timing of each microcomputer, the timing of the trigger signals may be offset, potentially resulting in sensor values ​​being acquired at different times. Therefore, in this detection device, one microcomputer monitors the trigger signal of the other microcomputer and adjusts the transmission timing of its own trigger signal to ensure that the transmission timing of the trigger signals of the two microcomputers is consistent.

[0006] Patent Document 1: Japanese Patent Application Publication No. 2018-106513

[0007] In the prior art of Patent Document 1, additional computing power is required to adjust the transmission timing of trigger signals between microcomputers. Furthermore, for example, it is assumed that multiple communication modules corresponding to multiple sensor values ​​transmitted from a torque sensor are housed within a single microcomputer. In this structure, there is a problem of increased signal output terminals and wiring time for the microcomputer when trigger signals are independently output from the trigger signal generation unit of each communication module to the communication path transmitting each sensor value. Summary of the Invention

[0008] The purpose of this disclosure is to provide a communication system that ensures the simultaneity of multiple sensor values ​​transmitted via multiple communication paths with a simple structure.

[0009] The communication system disclosed herein includes one or more sensor devices and one or more microcomputers. The sensor devices have multiple sensor elements that detect sensor values ​​related to a certain physical quantity from the same object.

[0010] The microcomputer has one or more receiving units, physical quantity calculation units, and control quantity calculation units. The receiving unit is arranged correspondingly to the sensor device and receives signals containing sensor values ​​sent from multiple sensor elements of the sensor device.

[0011] The physical quantity calculation unit calculates physical quantities based on multiple sensor values. The control quantity calculation unit uses physical quantities to calculate specified control quantities. For example, in the case of a communication system applied to an electric power steering system, the physical quantity is the steering torque, and the control quantity is the auxiliary quantity.

[0012] A receiving unit has multiple signal acquisition units and a transmission trigger signal generation unit.

[0013] Multiple signal acquisition units are connected to the sensor elements of corresponding sensor devices via independent communication paths. When the communication path becomes transmittable, they acquire the sensor values ​​transmitted via the communication path. A transmission trigger signal generation unit generates a shared transmission trigger signal to enable simultaneous transmission through multiple communication paths.

[0014] In a receiving unit, multiple signal acquisition units can simultaneously acquire multiple sensor values ​​by sharing a transmission trigger signal.

[0015] Therefore, the microcomputer can ensure the simultaneity of multiple sensor values ​​acquired from the sensor device. This prevents the microcomputer from calculating incorrect physical quantities based on sensor values ​​acquired at different times, or from falsely detecting anomalies in sensor values. Furthermore, since each receiver outputs a transmission trigger signal, the number of signal output terminals and wiring time for the microcomputer can be reduced, resulting in a simpler structure. Attached Figure Description

[0016] The above-mentioned objects, as well as other objects, features, and advantages of this disclosure, will become clearer from the following detailed description with reference to the accompanying drawings.

[0017] Figure 1 This is a schematic block diagram of the communication system according to the first embodiment.

[0018] Figure 2 This is a block diagram of the microcomputer in the communication system of the first embodiment.

[0019] Figure 3 This is a simplified structural diagram of the electric power steering device used in the communication system.

[0020] Figure 4 It is a timing diagram illustrating the relationship between the transmission of trigger signals and sensor values.

[0021] Figure 5A This is a sensor characteristic diagram of the first sensor device.

[0022] Figure 5B This is a sensor characteristic diagram of the second sensor device.

[0023] Figure 6 This is a flowchart illustrating the processing of the first anomaly detection unit.

[0024] Figure 7 This is a flowchart illustrating the processing of the second anomaly determination unit.

[0025] Figure 8 This is a flowchart showing the processing of the torque calculation unit.

[0026] Figure 9 This is a schematic block diagram of the communication system according to the second embodiment.

[0027] Figure 10 This is a block diagram of the microcomputer in the communication system of the second embodiment.

[0028] Figure 11 This is a schematic block diagram of a comparative communication system.

[0029] Figure 12 This is a flowchart of the synchronous processing equivalent to the comparative example in Patent Document 1. Detailed Implementation

[0030] Several embodiments of the communication system will be described with reference to the accompanying drawings. Structures substantially the same in the first and second embodiments will be labeled with the same reference numerals and their descriptions will be omitted. The first and second embodiments described below are referred to as "this embodiment". The communication system of this embodiment is applied to an electric power steering system, and calculates the assistance amount based on the driver's steering torque detected by a sensor device.

[0031] (First Implementation)

[0032] Reference Figures 1 to 8 The communication system 100 of the first embodiment will now be described. First, referring to... Figure 1 , Figure 2 The system structure will be described below. The communication system 100 of the first embodiment includes two redundantly arranged sensor devices 301 and 302 and a microcomputer 70. Hereinafter, the unit of the constituent elements corresponding to one sensor device will be referred to as "system". The communication system of this embodiment is a dual-system structure. Figure 1 This mainly illustrates the communication structure between sensor devices 301 and 302 and microcomputer 70. Figure 2 The main illustration shows the structure of the microcomputer 70.

[0033] The sensor device 301 of the first system is referred to as "first sensor device 301", and the sensor device 302 of the second system is referred to as "second sensor device 302". Furthermore, in the microcomputer 70, the components corresponding to the first sensor device 301 are labeled "first", and the components corresponding to the second sensor device 302 are labeled "second" for distinction. Since the structures of the first system and the second system are identical, the first system will be primarily described, and the description of the second system will be appropriately omitted. The omitted parts of the second system will be explained by replacing "1" with "2" in the reference numerals in the drawings of the first system.

[0034] The first sensor device 301 has multiple sensor elements 31A and 31B, which detect sensor values ​​related to the driver's steering torque from the same detection object as a "certain physical quantity". In this embodiment, the first sensor device 301 has two sensor elements 31A and 31B. Figure 1 In the attached drawing, the sensor element indicated by reference numeral 31A is designated as "sensor element 1A", and the sensor element indicated by reference numeral 31B is designated as "sensor element 1B". Furthermore, the sensor values ​​of the steering torque detected by sensor elements 31A and 31B are designated as S1A and S1B, respectively.

[0035] For example, when using Hall elements as magnetic detection elements as sensor elements 31A and 31B, the Hall IC, as a package containing the Hall elements, is equivalent to sensor device 301. Sensor elements 31A and 31B in... Figure 3 Within the steering torque sensor 93 shown, the magnetic displacement of a magnetic collecting ring based on the torsion angle of the torsion bar is detected, converted into a voltage signal, and output. In this example, the magnetic collecting ring is equivalent to the "detection object." Alternatively, magnetic detection elements other than Hall elements, or elements that detect changes other than magnetic properties, can be used as sensor elements 31A and 31B.

[0036] In this embodiment, the sensor device 301 transmits a sensor signal, containing information about sensor values ​​S1A and S1B detected by sensor elements 31A and 31B, as a digital signal via communication paths 41A and 41B at a certain transmission cycle. Specifically, the sensor signal uses a half-byte signal conforming to the SAE-J2716 standard, a signal using the so-called SENT (Single-sided half-byte transmission) method. The sensor device 301 is driven in SPC (Short PWM Code) mode using the SENT communication method, and communication begins via a trigger signal from the microcomputer 70. Furthermore, in... Figure 1 The diagrams of the transmitting circuit, operating power supply line, reference potential line, etc., are omitted.

[0037] The microcomputer 70 includes dual-system receiving units 501 and 502 and anomaly determination units 761 and 762, which are provided corresponding to the sensor devices 301 and 302, as well as a torque calculation unit 77 and an auxiliary quantity calculation unit 78 shared by the dual systems. The torque calculation unit 77 is equivalent to a "physical quantity calculation unit", and the auxiliary quantity calculation unit 78 is equivalent to a "control quantity calculation unit".

[0038] Regarding the structure within the microcomputer 70, since the structures of the first system and the second system are identical, the first system will be primarily described, with the description of the second system appropriately omitted. Furthermore, for the trigger signal generation unit, the reference numerals for the trigger signal generation unit of the first system are designated "63A, 63B," and the reference numerals for the trigger signal generation unit of the second system are designated "64A, 64B." Through a timer within the microcomputer 70, the trigger signal generation units of the receiving units 501 and 502 of the dual systems are configured to synchronously generate the trigger signals described later.

[0039] The first receiving unit 501 receives signals including sensor values ​​S1A and S1B transmitted from sensor elements 31A and 31B of the first sensor device 301. The first receiving unit 501 has two signal acquisition units 61A and 61B and two trigger signal generation units 63A and 63B. In particular, in this embodiment, the signal acquisition units 61A and 61B and the trigger signal generation units 63A and 63B are grouped together to form a SENT module.

[0040] The SENT module 51A corresponding to sensor element 31A has a signal acquisition unit 61A and a trigger signal generation unit 63A. The SENT module 51B corresponding to sensor element 31B has a signal acquisition unit 61B and a trigger signal generation unit 63B. Figure 1 , Figure 2 In the figure, the SENT module indicated by reference numeral 51A is denoted as "SENT module 1A", and the SENT module indicated by reference numeral 51B is denoted as "SENT module 1B".

[0041] Signal acquisition units 61A and 61B are connected to the sensor elements 31A and 31B of the corresponding sensor device 301 via independent communication paths 41A and 41B. When communication paths 41A and 41B are in a transmittable state, signal acquisition units 61A and 61B acquire sensor values ​​SiA and S1B transmitted via communication paths 41A and 41B. Trigger signal generation units 63A and 63B both generate trigger signals. However, as will be explained below, the trigger signals generated in trigger signal generation units 63A and 63B are used differently.

[0042] Here, one of the two SENT modules 51A and 51B included in the first receiving unit 501, SENT module 51B, is defined as a "representative module", and SENT module 51A other than the representative module is defined as a "general module".

[0043] The trigger signal generated by the trigger signal generation unit 63B of the SENT module 51B, which serves as the representative module, is output to communication paths 41A and 41B as a shared "transmission trigger signal Trc1" in the first system. The shared transmission trigger signal Trc1 enables simultaneous transmission on both communication paths 41A and 41B. In other words, the trigger signal generation unit 63B of the representative module functions as a "transmission trigger signal generation unit" within the first receiving unit 501. Within the first receiving unit 501, the two signal acquisition units 61A and 61B can simultaneously acquire sensor values ​​S1A and S1B using the shared transmission trigger signal Trc1.

[0044] Furthermore, the trigger signal generated by the trigger signal generation unit 63B is also used as an "internal trigger signal" to switch the signal acquisition unit 61B within this module 51B to a receptive state. In other words, the trigger signal generated by the trigger signal generation unit 63B, representing module 51B, is used as a "transmission trigger signal that also serves as an internal trigger signal."

[0045] On the other hand, the trigger signal generated by the trigger signal generation unit 63A of the SENT module 51A, which is a general module, is only used as an "intra-module trigger signal" to switch the signal acquisition unit 61A within this module 51A to a receptive state. Since the generated trigger signal is not used as a transmission trigger signal for the corresponding communication path 41A, the operation of the trigger signal generation unit 63A of the general module is to generate a trigger signal in SPC mode and not output it to the communication path 41A; therefore, it is commonly referred to as "no-load transmission". The effect of this structure will be described later in comparison with a comparative example.

[0046] Next, the first anomaly determination unit 761 determines anomalies in the sensor values ​​S1A and S1B transmitted from the sensor elements 31A and 31B of the first sensor device 301. Similarly, the second anomaly determination unit 762 determines anomalies in the sensor values ​​S2A and S2B transmitted from the sensor elements 32A and 32B of the second sensor device 302. For the processing performed by the first anomaly determination unit 761 and the second anomaly determination unit 762, refer to... Figures 5A to 7 To be discussed later.

[0047] The torque calculation unit 77 calculates the steering torque based on the multiple sensor values ​​S1A, S1B, S2A, S2B received by the receiving units 501 and 502 of the dual systems, and the abnormal information determined by the abnormality determination units 761 and 762. For the processing of the torque calculation unit 77, refer to... Figure 8 Described later. The auxiliary quantity calculation unit 78 calculates the steering torque calculated by the torque calculation unit 77, and the auxiliary quantity output by the calculation motor 80 is used as the "prescribed control quantity".

[0048] Here, refer to Figure 3 A brief description of the structure of the electric power steering device in the application communication system 100 is provided. Figure 3 The electric power steering system 90 shown is a column-assisted type, but the same applies to rack-assisted electric power steering systems. A steering shaft 92 is connected to the steering wheel 91. A pinion 96 located at the front end of the steering shaft 92 meshes with a rack shaft 97. A pair of wheels 98 are mounted at both ends of the rack shaft 97 via tie rods or the like. When the driver rotates the steering wheel 91, the steering shaft 92 connected to the steering wheel 91 rotates. The rotational motion of the steering shaft 92 is converted into linear motion of the rack shaft 97 via the pinion 96, and the pair of wheels 98 are steered at an angle corresponding to the displacement of the rack shaft 97.

[0049] The electric power steering system 90 includes a steering torque sensor 93, an ECU (control unit) 700, a motor 80, and a reduction gear 94. The steering torque sensor 93 is located midway along the steering shaft 92 and detects the driver's steering torque. In this embodiment, the steering torque sensor 93 redundantly includes two sensor devices 301 and 302. Furthermore, in addition to the sensor devices 301 and 302, the steering torque sensor 93 is configured to include a torsion bar, a multipole magnet, a magnetic yoke, and a magnetic collecting ring. Since these structures are known, they are not shown in the figures.

[0050] The ECU700 consists of a microcomputer 70 and a pre-driver (not shown), and includes a CPU, ROM, RAM, I / O, and buses connecting these structures. The ECU700 performs control based on software processing, which is based on pre-stored programs executed by the CPU, and hardware processing, which is based on dedicated electronic circuitry.

[0051] The auxiliary quantity calculation unit 78 of the microcomputer 70 calculates the auxiliary quantity (auxiliary torque command) output by the motor 80 based on the sensor value obtained from the steering torque sensor 93, and controls the energization of the motor 80 according to the auxiliary quantity. The motor 80 is, for example, a three-phase brushless motor. The auxiliary torque output by the motor 80 is transmitted to the steering shaft 92 via the reduction gear 94. The motor 80 can also be integrated with the ECU 700.

[0052] As a prior art in the field of communication systems like the above, a detection device that synchronizes the timing of sending the trigger signal for SENT communication in two microcomputers is disclosed in Patent Document 1 (Japanese Patent Application Publication No. 2018-106513). Figure 12 The flowchart illustrates the synchronous processing equivalent to the comparative example in Patent Document 1. In the following description of the flowchart, the symbol "S" denotes a step. Figure 12 The left column shows the processing of the first microcomputer, and the right column shows the processing of the second microcomputer.

[0053] In step S911, the first microcomputer sends a trigger signal to sensor S1#N, and in step S921, it receives sensor values ​​(measurement data) from sensor S1#N. Similarly, in step S912, the second microcomputer sends a trigger signal to sensor S2#N, and in step S922, it receives sensor values ​​(measurement data) from sensor S2#N. Here, both sensors S1#N and S2#N measure the same data, requiring simultaneity of sensor values. However, since the transmission timing of steps S911 and S912 is based on the computation timing of each microcomputer, timing discrepancies may occur.

[0054] Therefore, in S93, the second microcomputer monitors the trigger signal transmission timing of the first microcomputer, and in S94, adjusts the trigger signal transmission timing of the second microcomputer to make the trigger signal transmission timing of the two microcomputers consistent. This ensures the simultaneity of sensor values ​​from sensors S1#N and S2#N.

[0055] However, in Patent Document 1, for example, the multiple sensors S1#1 to #N corresponding to the first microcomputer measure different objects. That is, it does not disclose a structure where multiple sensor values ​​for the same measurement object are acquired by different signal acquisition units within a single microcomputer, as in this embodiment. If the idea of ​​Patent Document 1 is applied to the timing of trigger signal transmission between the multiple SENT modules 51A and S52A in the first receiving unit 501 of this embodiment, additional computing power from the microcomputer would be required. In contrast, in this embodiment, the simultaneity of sensor values ​​is ensured without increasing computing power.

[0056] Next, refer to Figure 4 The timing diagram illustrates the timing of signals transmitted from sensor elements 31A and 31B to communication paths 41A and 41B. Reference numerals for the first system are used throughout the text. The timing of signals transmitted from sensor elements 32A and 32B of the second system to communication paths 42A and 42B is similarly illustrated.

[0057] For example, a switching element is provided between communication paths 41A and 41B and ground. If a trigger signal is turned on and input to the gate of the switching element, the switching element is turned on, and current flows through communication paths 41A and 41B to ground, thus interrupting transmission. If the trigger signal is turned off, the switching element is turned off, and communication paths 41A and 41B become transmittable. That is, each communication path 41A and 41B becomes transmittable when the trigger signal input to the gate of the switching element provided in each communication path 41A and 41B is temporarily turned on and then turned off. In this structural example, in this embodiment, the trigger signal input to the gate of the switching element is defined as a "transmission trigger signal".

[0058] However, there is a timing offset in the trigger signals generated by the two SENT modules 51A and 51B in a receiving unit 501. Figure 4 In the example shown, the timing ta of the trigger signal of SENT module 51A being turned on and then turned off, and the timing tb of the trigger signal of SENT module 51B being turned on and then turned off, are offset by time δ.

[0059] Here, refer to Figure 11 The structure of the comparative example communication system 109 will be described below. In the comparative example communication system 109, the trigger signal generation units 63A and 63B of each SENT module 51A and 51B of the first receiving unit 501 independently output transmission trigger signals Tr1A and Tr1B to the corresponding communication paths 41A and 41B, respectively. Similarly, the trigger signal generation units 64A and 64B of each SENT module 52A and 52B of the second receiving unit 502 independently output transmission trigger signals Tr2A and Tr2B to the corresponding communication paths 42A and 42B, respectively.

[0060] Therefore, for example, if the timing offset of the trigger signals Tr1A and Tr1B is transmitted in the first system, there is a possibility that each signal acquisition unit 61A and 61B will obtain different timing sensor values ​​from each sensor element 31A and 31B. Thus, there is a concern that the microcomputer 70 may calculate the torque incorrectly or falsely detect abnormal sensor values.

[0061] Furthermore, in the comparative example, it is necessary to independently output transmission trigger signals Tr1A and Tr1B to the communication paths 41A and S1B that transmit the values ​​of each sensor S1A and S1B, respectively, which raises the issue of increased signal output terminals and connection time for the microcomputer 70. Figure 11 In the comparative example shown, two terminals are required to output transmission trigger signals Tr1A and Tr1B from the first receiving unit 501.

[0062] In contrast, in this embodiment, the trigger signal of the SENT module 51A, which is a general module, is only used as an intra-module trigger signal to switch the signal acquisition unit 61A to a receptive state, and does not function as a transmission trigger signal to make the communication path 41A transmissible. On the other hand, the trigger signal of the SENT module 51B, which is a representative module, is used as an intra-module trigger signal to switch the signal acquisition unit 61B to a receptive state, and also as a transmission trigger signal to make the communication paths 41A and 41B of both parties transmissible. Therefore, ignoring the timing ta, the signal transmission from the sensor elements 31A and 31B to the signal acquisition units 61A and 61B begins simultaneously with the timing tb when the shared transmission trigger signal is turned on and off.

[0063] Signals from sensor elements 31A and 31B are output in a frame as a series of signals consisting of a Cal&Sync signal, a Status signal, a Sensor Data signal, a CRC signal, and an End signal. SENT mode is a bidirectional communication transmission method using 4-bit half-byte signals. The sensor data signals containing the steering torque sensor values ​​S1A and S1B are 3 half-bytes (12 bits) in size, capable of sending a maximum of "000" to "FFF". 12 4096 types of data values. Signal acquisition units 61A and 61B receive signals in SENT mode and acquire the sensor values ​​S1A and S1B contained in the signals.

[0064] Thus, in this embodiment, within a single receiving unit 501, two signal acquisition units 61A and 61B can simultaneously acquire two sensor values ​​S1A and S1B via a shared transmission trigger signal Trc1. Therefore, the simultaneity of the multiple sensor values ​​S1A and S1B acquired by the microcomputer 70 from the sensor device 301 can be ensured. Consequently, it is possible to prevent the microcomputer 70 from calculating incorrect torque based on sensor values ​​acquired at different times, or from falsely detecting abnormalities in the sensor values.

[0065] Furthermore, in this embodiment, since each receiving unit 501 outputs a transmission trigger signal Trc1, the signal output terminals and wiring time of the microcomputer 70 can be reduced. That is, as... Figure 1 , Figure 2 As shown, only one terminal is needed to output the transmission trigger signal Trc1 from the first receiving unit 501. Therefore, a simple structure can be achieved.

[0066] Next, refer to Figures 5A to 7 The processing of the first anomaly determination unit 761 and the second anomaly determination unit 762 will be explained. For example... Figure 5A , Figure 5B As shown, normal sensor values ​​S1A, S1B, S2A, and S2B are values ​​within the specified range of 0 to 4095, excluding the lower limit near 0 and the upper limit near 4095. The lower and upper limits are excluded here and are considered "outside the specified range." Sensor values ​​S1A, S1B, S2A, and S2B falling outside the specified range are considered abnormal.

[0067] Furthermore, in this embodiment, the two sensor values ​​detected by the two sensor elements of each system have a crossover characteristic. One of the sensor values ​​in the crossover characteristic is a positive characteristic sensor value that has a linear output characteristic that is positively correlated with the actual torque. The other sensor value in the crossover characteristic is a negative characteristic sensor value that has a linear output characteristic that is negatively correlated with the actual torque, wherein the absolute value of the slope of the negative characteristic sensor value is equal to the absolute value of the slope of the positive characteristic sensor value.

[0068] For example, in the first sensor device 301, sensor value S1B corresponds to a positive characteristic sensor value, and sensor value S1A corresponds to a negative characteristic sensor value. In the second sensor device 302, sensor value S2A corresponds to a positive characteristic sensor value, and sensor value S2B corresponds to a negative characteristic sensor value. The positive and negative characteristic sensor values ​​are symmetrical values ​​centered at 2048, and the sum of the positive and negative characteristic sensor values ​​is 4096. If the sum of the positive and negative characteristic sensor values ​​deviates from a predetermined range before or after 4096, the anomaly determination units 761 and 762 determine that at least one sensor value is abnormal.

[0069] exist Figure 6 In S51, the first anomaly determination unit 761 acquires sensor values ​​S1A and S1B. In S52, it determines whether sensor values ​​S1A and S1B are within a certain range. Figure 5A The system determines whether the sensor device 301 is malfunctioning if it is outside the specified range shown, or if the absolute value of the difference between the sum of sensor values ​​S1A and S1B and 4096 exceeds a threshold. If the result is "yes" in S52, then in S53, the first anomaly determination unit 761 determines that the first sensor device 301, which outputs at least one abnormal sensor value, is malfunctioning. If the result is "no" in S52, then in S54, the first anomaly determination unit 761 determines that the first sensor device 301 is normal.

[0070] and Figure 6 Similarly, in Figure 7 In step S61, the second anomaly determination unit 762 acquires sensor values ​​S2A and S2B. In step S62, it is determined whether sensor values ​​S2A and S2B are within a certain range. Figure 5BThe system determines whether the second sensor device 302 is malfunctioning if it is outside the specified range, or if the absolute value of the difference between the sum of sensor values ​​S2A and S2B and 4096 exceeds a threshold. If the result is "yes" in S62, then in S63, the second anomaly determination unit 762 determines that the second sensor device 302 is malfunctioning because it outputs at least one abnormal sensor value. If the result is "no" in S62, then in S64, the second anomaly determination unit 762 determines that the second sensor device 302 is normal.

[0071] For example, in anomaly detection based on the sum of sensor values ​​with cross-reactivity, there is a possibility of falsely detecting anomalies if the simultaneity of sensor values ​​is not ensured. In this embodiment, false anomalies are prevented by using shared transmission trigger signals Trc1 and Trc2 to ensure the simultaneity of sensor values.

[0072] Next, refer to Figure 8 The processing of the torque calculation unit 77 will be explained. In S71, the torque calculation unit 77 acquires four sensor values ​​S1A, S1B, S2A, and S2B. In S72, the torque calculation unit 77 converts the sensor values, which are dimensionless numbers from 0 to 4095, into torque values ​​T1 and T2 [Nm] for each system according to equations (1) and (2). Kt is the conversion gain. The sign of the conversion gain Kt is appropriately determined according to the definition of positive and negative values ​​of torque and sensor values. In this embodiment, T1 and T2 are values ​​with opposite signs.

[0073] T1=(S1A-S1B)×Kt…(1)

[0074] T2=(S2A-S2B)×Kt…(2)

[0075] In steps S73 and S74, it is determined whether sensor devices 301 and 302 are malfunctioning. If the malfunction determination units 761 and 762 determine that either sensor device is malfunctioning, the microcomputer 70 continues calculations using only the sensor values ​​from the sensor devices in the normal system. Furthermore, in... Figure 8 In this case, the premise is that a dual fault occurs where both sensor devices 301 and 302 fail.

[0076] If the anomaly determination unit 761 determines that the first sensor device 301 is malfunctioning, the determination is "yes" in S73, and the process moves to S75. In S75, the torque value (-T2) of the second system is used as the steering torque. If the anomaly determination unit 762 determines that the second sensor device 302 is malfunctioning, the determination is "no" in S73, and "yes" in S74, and the process moves to S76. In S76, the torque value T1 of the first system is used as the steering torque.

[0077] If both sensor devices 301 and 302 are functioning normally, the system is judged as "no" in S73 and "yes" in S74, then proceeds to S77. In S77, the average torque value of the two systems ((T1-T2) / 2) is used as the steering torque.

[0078] In equations (1) and (2), since the torque value is calculated based on the difference between sensor values, there is a possibility of calculating incorrect torque values ​​T1 and T2 if the simultaneity of the sensor values ​​is not ensured. In this embodiment, the simultaneity of sensor values ​​is ensured by using shared transmission trigger signals Trc1 and Trc2 to prevent the calculation of incorrect torque values.

[0079] (Second Implementation)

[0080] Reference Figure 9 , Figure 10 The communication system 200 of the second embodiment will be described. Figure 9 , Figure 10 Corresponding to the first embodiment Figure 1 , Figure 2 The communication system 200 of the second embodiment corresponds to the dual-system sensor devices 301 and 302, each system having two microcomputers 701 and 702. The dual-system microcomputers 701 and 702 each have receiving units 501 and 502, anomaly determination units 761 and 762, torque calculation units 771 and 772, and auxiliary quantity calculation units 781 and 782.

[0081] The first microcomputer 701 calculates the steering torque T1 in the torque calculation unit 771 and the auxiliary quantity in the auxiliary quantity calculation unit 781 based on the sensor values ​​S1A and S1B obtained from the two sensor elements 31A and 31B of the first sensor device 301. The second microcomputer 702 calculates the steering torque T2 in the torque calculation unit 772 and the auxiliary quantity calculation unit 782 based on the sensor values ​​S2A and S2B obtained from the two sensor elements 32A and 32B of the second sensor device 302.

[0082] Microcomputers 701 and 702 communicate with each other via inter-microcomputer communication. Consequently, the trigger signal generation units 63B and 64B of the receiving units 501 and 502 of the dual systems synchronously generate transmission trigger signals Trc1 and Trc2. Furthermore, torque calculation units 771 and 772 calculate the steering torque based on anomaly information determined by the anomaly determination units 761 and 762 of this system and other systems. The calculation results of each torque calculation unit 771 and 772, as well as each auxiliary quantity calculation unit 781 and 782, are coordinated as needed.

[0083] In the communication system 200 of the second embodiment, since the microcomputers 701 and 702 are redundantly provided, even if any one of the microcomputers malfunctions, the calculation results of the normal microcomputer can be used to continue the calculation of auxiliary quantities.

[0084] (Other implementation methods)

[0085] (a) A sensor device may also have three or more sensor elements, and correspondingly, a receiving unit of a microcomputer may have three or more signal acquisition units. For example, a receiving unit corresponding to three sensor elements may consist of a representative module and two general modules. The transmission trigger signal generated by the trigger signal generation unit of the representative module is distributed to the three communication paths, enabling the three communication paths to transmit simultaneously.

[0086] (b) The communication system is not limited to a dual-system approach; it may also include a single-system or three-system or more sensor devices and receivers. In a single-system communication system, multiple signal acquisition units can simultaneously acquire multiple sensor values ​​by sharing a transmission trigger signal between a sensor device and a receiver. Furthermore, in a three-system or more approach where each system has a microcomputer, the transmission trigger signals for each microcomputer can be generated synchronously through communication between the three or more microcomputers.

[0087] (c) For example, the signal acquisition units 61A and 61B of the first receiving unit 501 may not be configured as modules grouped with the trigger signal generation units 63A and 63B. Furthermore, the method for making the signal acquisition units 61A and 61B receptive is not limited to trigger signals from within the modules of the trigger signal generation units 63A and 63B. If the signal acquisition units 61A and 61B do not require a structure with trigger signals within the modules, the trigger signal generation unit 63A, which does not function as a transmission trigger signal generation unit, may not be present.

[0088] (d) In cases where the probability of an anomaly in the sensor value is essentially zero, or where an anomaly would have no impact, the microcomputer may not need an anomaly detection unit. Furthermore, the characteristics of the two sensor values ​​are not limited to cross-correlation; they can also be positively correlated or negatively correlated with the actual physical quantity.

[0089] (e) The physical quantity detected by the sensor element and calculated by the physical quantity calculation unit of the microcomputer is not limited to torque, but can also be any physical quantity such as rotation angle, stroke, speed, load, pressure, etc. Correspondingly, the control quantity calculated by the control quantity calculation unit of the microcomputer using physical quantities is not limited to auxiliary quantities, and current command value, speed command value, etc. can be appropriately set.

[0090] (f) The digital communication method (protocol) of the communication system is not limited to the SENT method; other protocols may also be used. Sensor signals are not limited to 4-bit half-byte signals; 8-bit byte signals may also be used. Furthermore, the sensor device may also transmit sensor values ​​to the receiving unit of the microcomputer as analog signals.

[0091] (g) In addition to electric power steering, the communication system disclosed herein can also be applied to any device that performs calculations of control quantities based on detected sensor values.

[0092] The present disclosure is not limited in any way to the above-described embodiments and can be implemented in various forms without departing from its spirit.

[0093] The control device and method described in this disclosure can also be implemented using a dedicated computer, which is provided by comprising a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the control device and method described in this disclosure can also be implemented using a dedicated computer provided by employing one or more dedicated hardware logic circuits to construct a processor. Alternatively, the control device and method described in this disclosure can also be implemented using one or more dedicated computers, which are composed of a combination of a processor and memory programmed to perform one or more functions and a processor composed of one or more hardware logic circuits. Furthermore, the computer program can also be stored as instructions to be executed by the computer on a computer-readable non-transferable tangible recording medium.

[0094] This disclosure is described based on embodiments. However, this disclosure is not limited to these embodiments and structures. This disclosure also includes various modifications and equivalent variations. In addition, various combinations and methods, further including only one, more than, or less than one of these elements, are also included in the scope and spirit of this disclosure.

Claims

1. A communication system comprising: One or more sensor devices having multiple sensor elements, wherein the multiple sensor elements detect sensor values ​​related to a certain physical quantity from the same detection object; and One or more microcomputers have one or more receiving units, physical quantity calculation units, and control quantity calculation units, wherein, The receiving unit is provided corresponding to the sensor device described above. The receiving unit receives a signal containing sensor values ​​transmitted from a plurality of sensor elements of the sensor device. The physical quantity calculation unit calculates the physical quantity based on the plurality of sensor values. The control quantity calculation unit uses the physical quantity to calculate a predetermined control quantity. One of the above receiving units has: Multiple signal acquisition units are connected to the sensor elements of the corresponding sensor devices via independent communication paths, and acquire the sensor values ​​transmitted via the communication paths when the communication paths are in a transmittable state. as well as A transmission trigger signal generation unit generates a shared transmission trigger signal to enable multiple communication paths to transmit simultaneously. In one of the aforementioned receiving units, multiple signal acquisition units can simultaneously acquire multiple sensor values ​​through a shared transmission trigger signal. The aforementioned signal acquisition unit and trigger signal generation unit are grouped together to form a module, wherein the trigger signal generation unit generates a trigger signal. The aforementioned trigger signal generation unit of the representative module functions as the aforementioned transmission trigger signal generation unit, wherein the aforementioned representative module is one of the plurality of aforementioned modules included in the aforementioned receiving unit.

2. The communication system according to claim 1, wherein, In a general module, the trigger signal generated by the trigger signal generation unit is used as an intra-module trigger signal to switch the signal acquisition unit within this module to a receptive state. The general module is a module other than the representative module among the plurality of modules included in the receiving unit. In the aforementioned representative module, the trigger signal generated by the trigger signal generation unit is used as the aforementioned transmission trigger signal, which also serves as the trigger signal within the aforementioned module.

3. The communication system according to claim 1, wherein, The aforementioned microcomputer also has an anomaly determination unit, which determines anomalies in the multiple sensor values ​​sent from the multiple sensor elements.

4. The communication system according to claim 3, wherein, The multiple sensor values ​​detected by the aforementioned sensor elements include positive characteristic sensor values ​​and negative characteristic sensor values. The positive characteristic sensor values ​​exhibit a positively correlated linear output characteristic with respect to the actual physical quantity, while the negative characteristic sensor values ​​exhibit a negatively correlated linear output characteristic with respect to the actual physical quantity. The absolute value of the slope of the negative characteristic sensor values ​​is equal to the absolute value of the slope of the positive characteristic sensor values. When the sum of the positive characteristic sensor value and the negative characteristic sensor value deviates from the specified range, the above-mentioned anomaly determination unit determines that at least one of the above-mentioned sensor values ​​is abnormal.

5. The communication system according to claim 3, wherein, The aforementioned sensor device comprises multiple systems, and the aforementioned microcomputer has receiving units for each of the multiple systems corresponding to the aforementioned sensor device. When the above-mentioned anomaly determination unit determines that any of the above sensor values ​​is abnormal, The aforementioned microcomputer continues its calculations using only the sensor values ​​from the aforementioned sensor device in a normal system.

6. The communication system according to any one of claims 1 to 5, wherein, The aforementioned sensor device comprises multiple systems, and the aforementioned microcomputer has receiving units for each of the multiple systems corresponding to the aforementioned sensor device. The transmission trigger signal generation units of the receiving units of the multiple systems are configured to generate the transmission trigger signals synchronously with each other.

7. The communication system according to any one of claims 1 to 5, wherein, The aforementioned sensor device transmits multiple sensor values ​​as SENT signals conforming to the SAE-J2716 standard of the Society of Automotive Technicians.

8. The communication system according to any one of claims 1 to 5, wherein, In an electric power steering system applied to a vehicle, the aforementioned sensor device detects the driver's steering torque, and the aforementioned microcomputer calculates the auxiliary quantity output by the motor based on the steering torque detected by the aforementioned sensor device.

9. A communication system, comprising: Multiple sensor devices, each having multiple sensor elements, wherein the multiple sensor elements detect sensor values ​​related to a certain physical quantity from the same object being detected; and One or more microcomputers have multiple system receiving units, physical quantity calculation units, and control quantity calculation units, among which, The receiving unit is provided corresponding to the sensor devices of the multiple systems. The receiving unit receives signals containing sensor values ​​transmitted from the multiple sensor elements of the sensor devices. The physical quantity calculation unit calculates the physical quantity based on the multiple sensor values. The control quantity calculation unit uses the physical quantity to calculate a predetermined control quantity. One of the above receiving units has: Multiple signal acquisition units are connected to the sensor elements of the corresponding sensor devices via independent communication paths, and acquire the sensor values ​​transmitted via the communication paths when the communication paths are in a transmittable state. as well as A transmission trigger signal generation unit generates a shared transmission trigger signal to enable multiple communication paths to transmit simultaneously. In one of the aforementioned receiving units, multiple signal acquisition units can simultaneously acquire multiple sensor values ​​through a shared transmission trigger signal. The transmission trigger signal generation units of the receiving units of the multiple systems are configured to generate the transmission trigger signals synchronously with each other.

10. The communication system according to claim 9, wherein, The aforementioned microcomputer also has an anomaly determination unit, which determines anomalies in the multiple sensor values ​​sent from the multiple sensor elements.

11. The communication system according to claim 10, wherein, The multiple sensor values ​​detected by the aforementioned sensor elements include positive characteristic sensor values ​​and negative characteristic sensor values. The positive characteristic sensor values ​​exhibit a positively correlated linear output characteristic with respect to the actual physical quantity, while the negative characteristic sensor values ​​exhibit a negatively correlated linear output characteristic with respect to the actual physical quantity. The absolute value of the slope of the negative characteristic sensor values ​​is equal to the absolute value of the slope of the positive characteristic sensor values. When the sum of the positive characteristic sensor value and the negative characteristic sensor value deviates from the specified range, the above-mentioned anomaly determination unit determines that at least one of the above-mentioned sensor values ​​is abnormal.

12. The communication system according to claim 10, wherein, The aforementioned sensor device comprises multiple systems, and the aforementioned microcomputer has receiving units for each of the multiple systems corresponding to the aforementioned sensor device. When the above-mentioned anomaly determination unit determines that any of the above sensor values ​​is abnormal, The aforementioned microcomputer continues its calculations using only the sensor values ​​from the aforementioned sensor device in a normal system.

13. The communication system according to any one of claims 9 to 12, wherein, The aforementioned sensor device transmits multiple sensor values ​​as SENT signals conforming to the SAE-J2716 standard of the Society of Automotive Technicians.

14. The communication system according to any one of claims 9 to 12, wherein, In an electric power steering system applied to a vehicle, the aforementioned sensor device detects the driver's steering torque, and the aforementioned microcomputer calculates the auxiliary quantity output by the motor based on the steering torque detected by the aforementioned sensor device.

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