ROTATION DETECTION DEVICE

Abstract

Rotation detection device comprising: a sensor section (130, 230) designed to detect the rotation of a motor (80) and to output first rotation information containing the rotation angle of the motor within one revolution of the motor, and second rotation information containing the number of revolutions of the motor; and a control section (170, 270) which contains: a signal acquisition device (171, 271) designed to obtain the first rotation information and the second rotation information from the sensor section; an absolute angle calculator (172, 272) designed to calculate an absolute angle that specifies a rotation quantity with respect to a reference position, based on the first rotation information and the second rotation information; an abnormality determiner (175, 275) designed to determine an abnormality in a calculation of the absolute angle; and a communicator (179, 279) designed to transmit and receive absolute angle information for the absolute angle, wherein The absolute angle calculator is also designed, in response to the abnormality in the calculation of the absolute angle, to use a pre-abnormality value of the absolute angle to calculate the absolute angle, wherein the pre-abnormality value of the absolute angle is calculated before the abnormality in the calculation of the absolute angle occurs. The absolute angle calculator is also designed to recover from the abnormality of the absolute angle calculation after an absolute recovery angle has been calculated, and to resume a normal absolute angle calculation. the sensor section and the control section are combined as one system and the rotation detection device contains at least two sensor section and control section systems, The absolute angle is referred to either as a subject-system absolute angle, if the absolute angle is calculated through a subject system, or an other-system absolute angle, when the absolute angle is calculated by a system other than the subject system, The absolute angle calculator, in response to the abnormality of calculating the absolute angle, is also designed to either use the pre-abnormality value of the absolute angle to calculate the absolute angle or the other-system absolute angle to calculate the absolute angle, and The absolute angle calculator is also designed to calculate the absolute recovery angle based on (i) the pre-abnormality absolute angle of the subject system (θa1_hold), (ii) a difference (Δθa2) between the pre-abnormality absolute angle of the other system and the absolute recovery angle of the other system, and (iii) a difference (θm1_r - θm1_hold) between the pre-abnormality absolute angle of the subject system and the recovery rotation angle of the subject system.

Description

[0001] The present invention relates to a rotation detecting device and an electric power steering device using the rotation detecting device.

[0002] JP 5 958 572 B2 and the corresponding DE 10 2015 102 161 A1 describe a rotation angle detection device that detects information that varies with a rotation of a motor. The rotation detection device includes: a sensor section configured to detect a rotation of a motor and output first rotation information including a rotation angle of the motor within one revolution of the motor and second rotation information including a number of revolutions of the motor; and a control section including: a signal acquisition device configured to acquire the first rotation information and the second rotation information from the sensor section;an absolute angle calculator configured to calculate an absolute angle indicating a rotation amount with respect to a reference position based on the first rotation information and the second rotation information; an abnormality determiner configured to determine an abnormality in a calculation of the absolute angle; and a communicator configured to transmit and receive absolute angle information for the absolute angle.

[0003] During rotation detection, a temporary abnormality of the rotation angle detection device may be detected due to noise affecting the communication between the rotation angle sensor and the control unit (e.g., signal noise), and the temporary abnormality may later disappear, allowing the device to return to a normal state. JP 5 958 572 B2 and DE 10 2015 102 161 A1 do not describe how the device recovers and returns to a normal state after such an abnormality is detected.

[0004] DE 102 49 369 A1 discloses a control device for a motor-driven power steering system of a motor vehicle, comprising: steering angle information detecting means for detecting steering angle information of a steering mechanism, a control device for controlling a motor current based on the steering angle information and magnitude and direction of a steering torque, wherein, in response to an abnormality in the calculation of the absolute angle, previous left angle information of the absolute angle is used to calculate the absolute angle, wherein the previous steering angle information is calculated before the abnormality in the calculation of the absolute angle occurs, and wherein, after a recovery absolute angle has been calculated, a normal absolute angle calculation is resumed.

[0005] DE 10 2017 205 863 A1 discloses a rotation detection device and an electric power steering device using the rotation detection device. A sensor includes a sensor element that outputs a measured value describing a rotation of a detection target, and a circuit module. The circuit module includes a rotation angle calculation unit that calculates, based on the measured value, rotation angle information describing a rotation angle of the detection target. The rotation angle calculation unit generates a rotation angle signal containing the rotation angle information. The circuit module includes a rotation number calculation unit that calculates, based on the measured value, rotation number information describing the number of rotations of the detection target. The rotation number calculation unit generates a rotation number signal containing the rotation number information.A signal output unit outputs a sequence of the rotation angle signal and the rotation number signal as an output signal. A controller receives the output signal from the communication unit and calculates information about the rotation of the detection target based on the output signal.

[0006] The object of the invention is to provide a rotation detection device and an electric power steering device using the rotation detection device, which are designed to recover from an abnormality affecting the rotation detection device. This object is achieved by a rotation detection device having the features of claim 1 and by an electric power steering device having the features of claim 2.

[0007] According to one aspect of the present invention, a rotation detection device includes a sensor section and a control section. The sensor section detects rotation of a motor and outputs (i) first rotation information regarding a rotation angle of the motor (electric motor) within one rotation of the motor and (ii) second rotation information regarding the number of revolutions of the motor.

[0008] The control section includes a signal acquisition device, an absolute angle calculator, an abnormality determiner, and a communicator. The signal acquisition device acquires the first rotation information and the second rotation information from the sensor section. The absolute angle calculator calculates an absolute angle based on the first rotation information and the second rotation information, where the absolute angle is a rotation quantity relative to a reference position. The abnormality determiner determines abnormalities in the absolute angle, such as abnormalities in the calculation of the absolute angle. The communicator can transmit and receive absolute angle information regarding the absolute angle.

[0009] When an abnormality occurs in the absolute angle of a subject system, which is one of two systems in the device, the absolute angle calculator can use the stored value of an absolute angle calculated before the abnormality was detected. When the absolute angle abnormality is resolved, the rotation detection device recovers from the abnormality and returns to a normal state, and the absolute angle calculation returns to the normal state after calculating an absolute recovery angle (i.e., returns to a normal absolute angle calculation). As a result, after a temporary abnormality occurs in the rotation detection device and / or electric power steering (EPS) device, the rotation detection device and / or EPS device can appropriately recover from the abnormality and return to the normal state.

[0010] Objects, features, and advantages of the present invention will become apparent from the following detailed description with reference to the accompanying drawings. Fig. 1 shows a schematic configuration of a steering system according to a first embodiment not according to the invention; Fig. 2 is a cross-sectional view of a drive device of the first embodiment; Fig. 3 a cross-sectional view of the drive device along the line III-III of Fig. 2; Fig. 4 is a block diagram of an electronic control unit (ECU) of the first embodiment; Fig. 5 is a block diagram of a control section of the first embodiment; Fig. 6 is a timing chart showing a mechanical angle and an absolute angle of the first embodiment; Fig. 7 defined or safe areas and undefined or unsafe areas of the first embodiment; Fig. 8 is a flowchart of an absolute angle calculation process of the first embodiment; Fig. 9 is a time chart of an abnormality treatment procedure and a recovery procedure of the first embodiment; Fig. 10 is a time chart showing an abnormality treatment procedure and a recovery procedure according to a second embodiment not according to the present invention; Fig. 11 is a time chart showing an abnormality treatment procedure and a recovery procedure according to a third embodiment not according to the present invention; Fig. 12 is a time chart of an abnormality treatment procedure and a recovery procedure according to a fourth embodiment not according to the invention; and Fig. 13 is a time chart of an abnormality treatment procedure and a recovery procedure according to a fifth embodiment of the present invention. (First embodiment not according to the invention)

[0011] A rotation detection device and an electric power steering device using such a rotation detection device will be described below with reference to the drawings. In the following embodiments, like features and elements in the embodiments may be denoted by the same reference numerals, and repeated descriptions of previously described like features and elements may be omitted from the description of the other embodiments.

[0012] In Fig. 1, an electronic control unit (ECU) 10 is configured as a rotation detection device according to the first embodiment. The ECU 10 includes an electric motor 80 as part of an electric power steering device 8 for assisting a steering operation of a vehicle. The motor 80 may also be referred to as an electric rotary machine. Fig. 1 shows an overall configuration of a steering system 90 including the electric power steering device 8. The steering system 90 includes a steering wheel 91, a steering shaft 92, a gear train 96, a rack 97, road wheels 98, and an electric power steering device 8.

[0013] The steering wheel 91 is arranged at one end of the steering shaft 92 and connected to the steering shaft 92. A torque sensor 94 is arranged on the steering shaft 92 to detect a steering torque Ts. The torque sensor 94 includes a first torque detector 194 and a second torque detector 294. The gear train 96 is arranged at the lower end of the steering shaft 92. The gear train 96 meshes with the rack 97. Road wheels 98 are coupled to both ends of the rack 97 via a mechanical link such as tie rods.

[0014] When a driver of the vehicle turns the steering wheel 91, the steering shaft 92, which is connected to the steering wheel 91, rotates. The gear train 96 converts the rotational movement of the steering shaft 92 into a linear movement to move the rack 97 linearly. The road wheels 98 are steered at an angle corresponding to the displacement of the rack 97.

[0015] The electric power steering device 8 includes a drive device 40 including the motor 80, the ECU 10, and a reduction gear 89. The reduction gear 89 is a drive train mechanism that reduces the speed of the motor 80 and transmits the rotation to the steering shaft 92. The electric power steering device 8 of the present embodiment is a column-assist type power steering device. However, the electric power steering device 8 is not limited to a column-assist type, but may alternatively be a rack-assist type electric power steering device 8 that transmits the rotation of the motor 80 to the rack 97.

[0016] The motor 80 outputs an assist torque to assist a steering operation. In other words, the motor 80 can provide either full or partial assistance to assist a vehicle user in turning the steering shaft 92 to steer the road wheels 98.

[0017] The engine 80 is more precisely in the Fig. 2 and Fig. 3. The motor 80 is driven by electric power supplied by batteries 191 and 291 located in Fig. 4, is supplied as DC power. The drive of the motor 80 in the forward and reverse directions causes the reduction gear 89, which is in Fig. 1, in the forward or reverse direction. The motor 80 is a brushless three-phase motor and has a rotor 860 and a stator 840, as shown in Fig. 2 is shown.

[0018] The motor 80 includes a first motor winding 180 as a first winding set and a second motor winding 280 as a second winding set. The motor windings 180 and 280 have the same electrical characteristics. For example, the motor windings 180 and 280 are wound together around the stator 840 so that the phases of the winding 180 are shifted by an electrical angle of 30 degrees with respect to the corresponding phases of the winding 280. The phase currents (for example, the U-phase, the V-phase, and the W-phase) are controlled to be supplied to the motor windings 180 and 280 such that the corresponding phase currents of the motor windings 180 and 280 have a phase difference φ of 30 degrees from each other. By optimizing the supply current phase difference, the output torque is improved and the torque ripple of the sixth-order harmonic can be reduced.Applying current with a phase difference φ of 30 degrees between the corresponding phases of motor windings 180 and 280 also averages the current, thereby advantageously maximizing noise and vibration cancellation. Since heat generation is also averaged, it is also possible to reduce errors in the torque value detection of torque sensors 194 and 294, since the detected torque values ​​may vary with temperature.

[0019] The Fig. The combination of a first driver circuit 120, a first sensor section 130, and a first control section 170, among other elements, shown in Figure 4, may also be referred to as a first system L1. The first system L1 is used to control the drive of the first motor winding 180 (for example, by controlling the power supplied to the first motor winding 180). The combination of a second driver circuit 220, a second sensor section 230, and a second control section 270, among other elements, may also be referred to as a second system L2. The second system L2 is used to control the drive of the second motor winding 280.Elements, components, and features included in the first system L1 may be designated by reference numerals based on 100 (e.g., 120, 170), and the elements, components, and features included in the second system L2 may be designated by reference numerals based on 200. Identical elements and features in the first system L1 and the second system L2 may be indicated by at least the last two digits. For example, the first control section 170 may be similar to the second control section 270 (e.g., the control sections 170 and 270 are similar components), with the reference numerals for the respective control sections 170 and 270 each including "70" as the last digits, with the prefix "1" (i.e.,The prefix "2" (the first digit) for the first control section 170 indicates that the first control section 170 is included in the first system L1, and the prefix "2" indicates that the second control section 270 is included in the second system L2. The descriptions of the first control section 170 and the second control section 270 may be similar to each other, and in such a case, redundant description of similar elements, components, and features may be omitted.

[0020] The drive device 40 may integrate the ECU 10 and the motor 80 within a single housing. The drive device 40 may be referred to as a machine-electronics integration type drive device 40. As described in Fig. 2, the ECU 10 may be arranged coaxially with the motor 80 at one end of the motor 80 along the longitudinal axis Ax (i.e., at one axial end of the motor 80). Alternatively, the motor 80 and the ECU 10 may be arranged separately. The ECU 10 is arranged on the side opposite the output of a shaft 870. Alternatively, the ECU 10 may be arranged on the shaft output side of the motor 80. By employing the machine-electronics integration type configuration, the drive device 40 including the ECU 10 and the motor 80 can be installed in more restricted spaces (i.e., smaller, narrower spaces) in the vehicle.

[0021] The motor 80 includes the stator 840, the rotor 860, and a housing 830, with the stator 840 and the rotor 860 housed within the housing 830. The stator 840 is fixed to the housing 830, and the motor windings 180 and 280 are wound around the stator 840. The rotor 860 is disposed within the stator 840. In other words, the stator 840 can surround the rotor 860. The rotor 860 can rotate relative to the stator 840.

[0022] The shaft 870 is attached to the rotor 860 to rotate integrally with the rotor 860. The shaft 870 is rotatably supported by the housing 830 through bearings 835 and 836. The end portion of the shaft 870 on the ECU 10 side protrudes from the housing 830 toward the ECU 10. A magnet 875 is included at the axial end of the shaft 870 on the ECU 10 side.

[0023] The housing 830 includes a cylindrical container 834 with a rear frame end 837 that closes the side of the housing 834 near the ECU 10. A front frame end 838 is attached to the open side of the container 834 to close the side of the container 834 near the output of the shaft 870. The container 834 and the front frame end 838 are fastened together by screws or similar fasteners (not shown). Lead wire insertion holes 839 are formed in the rear frame end 837. Lead wires 185 and 285, which are connected to a respective phase of the motor windings 180 and 280, are inserted through the lead wire insertion holes 839. The lead wires 185 and 285 pass through the lead wire insertion holes 839 toward the ECU 10 and are connected to a circuit board 470.

[0024] The ECU 10 includes a cover 460, a heat sink 465, the circuit board 470, and other electronic components mounted on the circuit board 470. The heat sink 465 may be fixed to the cover 460, and the circuit board 470 may be fixed to the heat sink 465.

[0025] The cover 460 protects the electronic components of the ECU 10 from external impacts and prevents dust and water from entering the interior of the ECU 10. The cover 460 integrally includes a cover main body 461 and a connector element 462. The connector element 462 and the cover main body 461 do not have to be integral and may alternatively be formed as two separate structural elements 461 and 462. The terminals 463 of the connector element 462 are connected to the circuit board 470 via wiring or similar electrical conductors (not shown). The number of connector elements 462 and the number of terminals may correspond to the number of electrical inputs and outputs (i.e., power, signals) to and from the ECU 10, as well as based on other design factors. The connector element 462 is disposed at an axial end of the drive device 40 on the side opposite the motor 80.The connector element 462 extends axially in the direction of the axis Ax away from the drive device 40 and is open to allow connection of an external connector (not shown) to the connector element 462.

[0026] The circuit board 470 is, for example, a printed circuit board and is arranged such that one side faces the rear frame end 837 in the direction of the motor 80 and another side faces away from the motor 80 in the direction of the cover 460. The electronic components of the first and second systems L1 and L2, which are Fig. 4 are mounted independently on the circuit board 470, so that the two systems are arranged in a fully redundant configuration. In the present embodiment, the electronic components of the first and second systems L1 and L2 are mounted on the circuit board 470, but the electronic components of the first and second systems L1 and L2 may alternatively be mounted on separate circuit boards. Not all electronic components of the first and second systems L1 and L2 need to be mounted on the circuit board, and the Fig. 2 and Fig. 3 not all electronic components used in Fig. 4 as being located on circuit board 470. The electronic components of the first and second systems L1 and L2 on circuit board 470 are described in more detail below.

[0027] Of the two main surfaces of the circuit board 470, the surface on the side of the motor 80 is referred to as a motor-side surface 471, and the other surface facing the cover 460 is referred to as a cover-side surface 472. As shown in Fig. 3, switching elements 121, switching elements 221, a rotation angle sensor 30, and customized integrated circuits (ICs) 159 and 259 are mounted on the motor-side surface 471. The rotation angle sensor 30 is mounted at a position facing the magnet 875 so that it is capable of detecting a change in the magnetic field caused by a rotation of the magnet 875. The rotation angle sensor 30 may be arranged centrally on the motor-side surface 471 of the circuit board 470, as shown in Fig. 3, so that the rotation angle sensor is arranged, for example, along the axis Ax coaxial with the shaft 870 and thus with the magnet 875, as shown in Fig. 2. The rotation angle sensor 30 may also be referred to as sensor section 30.

[0028] The switching elements 121 may form part of the first driver circuit 120, which in Fig. 4 (for example, inverter or INV 1). The switching elements 221 may form part of the second driver circuit 220 shown in Fig. 4 (for example inverter or INV 2).

[0029] Capacitors 128 and 228, coils 129 and 229 and control sections 170 and 270 are mounted on the cover side surface 472.

[0030] Small computers such as microcontrollers or systems on a chip (SoCs) may form the control sections 170 and 270, with respective separate computers forming the respective control sections 170 and 270. In other words, the control section 170 may be a microcontroller or SoC, and the control section 270 may be another microcontroller or SoC. Fig. 3, reference numerals 170 and 270 are assigned to the computers that are part of the control sections 170 and 270, respectively.

[0031] The capacitors 128 and 228 smooth respective electrical power from the batteries 191 and 291, which are in Fig. 4. Capacitors 128 and 228 also support the supply of electrical power to motor 80 by storing electrical charges. Capacitors 128 and 228 and coils 129 and 229 may be configured to form a filter circuit. For example, capacitor 128 and coil 129 may be combined to form an LC filter for first system L1. Capacitor 228 and coil 229 may be combined to form an LC filter for second system L2. The filter circuits reduce noise transmitted from other devices that also use batteries 191 and 291 and also reduce noise transmitted from drive device 40 to other devices that also use batteries 191 and 291.

[0032] Power supply relays, motor relays, and current sensors (all not shown in the drawings) may also be mounted on either the motor-side surface 471 or the cover-side surface 472.

[0033] As it is in Fig. 4, the ECU 10 includes the driver circuits 120 and 220 and the control circuits 170 and 270. In Fig. 4, the driver circuit is labeled "INV" (inverter). The first driver circuit 120 is a three-phase inverter having six switching elements 121. The first driver circuit 120 converts the electric power supplied to the motor winding 180 (for example, converts the direct current (DC) power from the battery 191 into alternating current (AC) power). The switching elements 121 are turned on and off based on control signals from the first control section 170. The second driver circuit 220 is a three-phase inverter having six switching elements 221. The second driver circuit 220 converts the electric power supplied to the second motor winding 280. The switching elements 221 are turned on and off based on control signals from the second control section 270.

[0034] As it is in Fig. As shown in Fig. 4, the rotation angle sensor 30 includes the first sensor section 130 and the second sensor section 230. The first sensor section 130 outputs an output signal SGN1 to the first control section 170, and the second sensor section 230 outputs an output signal SGN2 to the second control section 270. That is, in the present embodiment, the first sensor section 130 is included in the first system L1, and the second sensor section 230 is included in the second system L2.

[0035] Unless otherwise described, the configurations of components and elements in the ECU 10, the rotation angle sensor 30, and the drive device 40 described in the present embodiment are the same in the later embodiments.

[0036] The first sensor section 130 includes magnetic field detection units 131 and 132 and a signal processing unit 140. The second sensor section 230 includes magnetic field detection units 231 and 232 and a signal processing unit 240. Since the processes performed by the sensor sections 130 and 230 are the same, the description focuses on the details of the process performed by the first sensor section 130, and a similar description of the second sensor section 230 is omitted.

[0037] The magnetic field detection units 131, 132, 231, and 232 are detection elements that detect changes in the magnetic field of the magnet 875 based on the rotation of the motor 80 (for example, via the rotation of the rotor 860 and the shaft 870). A magnetoresistive (MR) sensor or a Hall sensor, for example, can be used as the respective magnetic field detection units 131, 132, 231, and 232. The magnetic field detection units 131, 132, 231, and 232 each have four sensor elements that output a "cos+" signal, a "sin+" signal, a "cos-" signal, and a "sin-" signal. The "cos+" signal, the "sin+" signal, the "cos-" signal, and the "sin-" signal can refer to the sensor signal either jointly or individually. Similarly, the sensor signal may refer to any or all of the “cos +” signal, the “sin +” signal, the “cos -” signal, and the “sin-” signal.

[0038] The signal processing unit 140 includes rotation angle calculators 141 and 142, a rotation counting unit 143, a self-diagnosis unit 145, and a communicator 146. The signal processing unit 240 includes rotation angle calculators 241 and 242, a rotation counting unit 243, a self-diagnosis unit 245, and a communicator 246.

[0039] The rotation angle calculator 141 calculates a mechanical angle θm1c based on the sensor signal from the magnetic field detection unit 131. The rotation angle calculator 142 calculates a mechanical angle θm1e based on the sensor signal from the magnetic field detection unit 132. The rotation angle calculator 241 calculates a mechanical angle θm2c based on the sensor signal from the magnetic field detection unit 231. The rotation angle calculator 242 calculates a mechanical angle θm2e based on the sensor signal from the magnetic field detection unit 232. The mechanical angles θm1c, θm1e, θm2c, and θm2e are calculated from the arctan of the "cos +" signal, the "sin +" signal, the "cos -" signal, and the "sin -" signal.

[0040] In the present embodiment, the mechanical angles θm1c and θm2c are calculated based on the detection signals (i.e., sensor signals) from the magnetic field detection units 131 and 231, respectively, and used for various calculations in the control sections 170 and 270. The calculated mechanical angles θm1e and θm2e are calculated based on the detection signals (i.e., sensor signals) from the magnetic field detection units 132 and 232, respectively, and used to detect abnormalities by comparing the mechanical angles θm1e and θm2e with the respective mechanical angles θm1c and θm2c. The magnetic field detection units 131 and 231 can be used for control and are designed “for control”, and the magnetic field detection units 132 and 232 can be used for abnormality detection and are designed “for abnormality detection”.Values ​​calculated by the rotation angle calculators 141, 142, 241 and 242 can be any values ​​that can be converted into mechanical angles.

[0041] The magnetic field detection units 131 and 231 for control and the magnetic field detection units 132 and 232 for abnormality detection may be the same type of magnetic field detection unit or different types. Since the magnetic field detection accuracy for abnormality detection may be significantly lower than the magnetic field detection accuracy for control, the detection accuracy of the magnetic field detection units 132 and 232 used for abnormality detection may be lower than the detection accuracy of the magnetic field detection units 131 and 231 used for control. By using different types of magnetic field detection devices for control and abnormality detection, the probability of the magnetic field detection units malfunctioning at the same time is reduced.If the same magnetic field sensing elements are used for the magnetic field sensing units 131, 132, 231, and 232, it may be possible to vary the layout and configuration of the magnetic field sensing units or to select sensing elements from different production batches to reduce the possibility of simultaneous malfunctions. The computing circuits of the rotation angle calculators 141, 142, 241, and 242 can be varied in a similar manner to reduce the likelihood of simultaneous circuit malfunctions.

[0042] The rotation counting unit 143 calculates a count value TC1 based on the signal from the magnetic field detecting unit 131. The rotation counting unit 243 calculates a count value TC2 based on the signal from the magnetic field detecting unit 231.

[0043] As it is in Fig. As shown in Fig. 7, the mechanical angle θm takes a value from 0° to 360° during one rotation of the motor 80. The rotation counting units 143 and 243 can set four counting ranges. In the present embodiment, the mechanical angle θm that is equal to or greater than 0° and less than 90° is referred to as "range R0", the mechanical angle θm that is equal to or greater than 90° and less than 180° is referred to as "range R1", the mechanical angle θm that is equal to or greater than 180° and less than 270° is referred to as "range R2", and the mechanical angle θm that is equal to or greater than 270° and less than 360° is referred to as "range R3". Each time the mechanical angle θm changes from one range to another, the count values ​​TC1 and TC2 are either counted up or down based on the direction of rotation.In the present embodiment, the count values ​​TC1 and TC2 are counted up when the motor 80 rotates in a forward direction, and are counted down when the motor 80 rotates in a reverse direction. That is, when the motor 80 makes one revolution in the forward direction, for example, from 0° to 360°, the count values ​​TC1 and TC2 are each counted up and increased by 4. When the motor 80 makes one revolution in the reverse direction, for example, from 360° to 0°, the count values ​​TC1 and TC2 are each counted down and decreased by 4.

[0044] As it is in Fig. As shown in Figure 4, the self-diagnosis unit 145 monitors for abnormalities such as short circuits in the power sources or ground faults in the first sensor section 130. The communicator 146 generates a first output signal SGN1 and transmits the first output signal SGN1 to the first control section 170. The first output signal SGN1 includes various signals such as the mechanical angles θm1c and θm1e, the count value TC1, and the self-diagnosis result. The first output signal SGN1 may include additional signals. The self-diagnosis unit 145 monitors for abnormalities in the second sensor section 230. The communicator 246 generates the second output signal SGN2 and transmits the second output signal SGN2 to the second control section 270. The second output signal SGN2 includes various signals such as the mechanical angles θm2c and θm2e, the count value TC2, and the self-diagnosis result.The second output signal SGN2 may include additional signals. The output signal of the present embodiment is a digital signal, and the communication method may use, for example, a serial interface (SPI) communication specification, but other communication methods may also be used.

[0045] Electrical power is supplied to the first sensor section 130 from the first battery 191 via power supplies 192 and 193. The power supplies 192 and 193 may be regulators or similar controllers. Electrical power is constantly supplied to the magnetic field detection unit 131 and the rotation counting unit 143 via the power supply 192. The magnetic field detection unit 131 and the rotation counting unit 143 are surrounded by a dashed line to indicate that these components constantly receive power from the power source 192 and constantly receive power for continuous detection and calculation even when the vehicle ignition switch is turned off. In the first sensor section 130, components other than the magnetic field detection unit 131 and the rotation counting unit 143 receive electrical power via the power supply 193 when the vehicle ignition switch (not shown) is turned on.When the ignition switch is turned off, the power supply to these components is stopped. Furthermore, when the ignition switch is turned on, electrical power is supplied to the first control section 170 via the power supply 193. The vehicle ignition switch may also be referred to as a start switch.

[0046] Electric power is supplied to the second sensor section 230 from the second battery 291 via the power supplies 292 and 293. Electric power is constantly supplied to the magnetic field detection unit 231 and the rotation counting unit 243 via the power supply 292. The magnetic field detection unit 231 and the rotation counting unit 243 are surrounded by a dashed line to indicate that these components constantly receive power from the power source 292 and constantly receive power for continuous detection and calculation even when the vehicle ignition switch is turned off. In the second sensor section 230, components other than the magnetic field detection unit 231 and the rotation counting unit 243 receive electric power via the power supply 293 when the vehicle ignition switch is turned on. When the ignition switch is turned off, the power supply to these components stops.In addition, electric power is supplied to the second control section 270 via the power supply 293 when the ignition switch is turned on.

[0047] A low-power element such as a tunneling magnetoresistive element (TMR) may be used for the respective magnetic field sensing units 131 and 231, which continuously receive power. To simplify the description, detailed descriptions of some supply and control lines, such as the connection line between the battery 191 and the power supply 193, may be omitted. The description may similarly omit a detailed description of electrical connections between electrical components with reference to other figures.

[0048] Alternatively, the rotation counting units 143 and 243 may calculate the count values ​​TC1 and TC2 based on the signals from the magnetic field detecting units 132 and 232, rather than using the signals from the magnetic field detecting units 131 and 231 themselves. In this case, electrical power may be continuously supplied to the magnetic field detecting units 132 and 232.

[0049] As described above, each of the control sections 170 and 270 may be a small computer such as a microcontroller or an SoC, including, for example, one or more CPUs or similar processor cores, a memory such as read-only memory (ROM), random access memory (RAM), or flash memory, input / output (I / O) interfaces, and a bus line for connecting these components. The processes executed by the control sections 170 and 270 may be implemented as a software process, a hardware process, or a combination of software and hardware. The software process may be implemented by causing the CPU to execute a program or instruction set stored in a memory. The program may be previously stored in a memory such as the ROM. The memory for storing the programThe instruction set is a computer-readable non-transitory tangible storage medium. The hardware process may be implemented by a special dedicated electronic circuit. In addition to the computers that form the control sections 170 and 270, the control sections 170 and 270 may include other hardware components that form specialized circuits for performing the processes associated with the control sections 170 and 270. Such circuits may be, for example, analog circuit components, digital circuit components, logic circuit components, or a combination of these circuit components configured to perform the processes associated with the control sections 170 and 270.According to another example, the control sections 170 and 270 may include one or more specialized circuits, such as application-specific integrated circuits (ASICs) or field-programmable gate arrays (FPGAs), configured to perform the processes associated with the control sections 170 and 270.

[0050] The first control section 170 and the second control section 270 are configured to communicate with each other. The communication between the control sections 170 and 270 may be referred to as "intercomputer communication." Any communication method, such as serial communication such as SPI or SENT, CAN communication, FlexRay communication, or the like, may be used for intercomputer communication between the control sections 170 and 270.

[0051] The first control section 170 generates control signals for controlling the turning on and off of the switching elements 121 in the driver circuit 120 for current feedback control. The control signals for current feedback control can be based, for example, on the mechanical angle θm1c, the detection values ​​of the current sensor (not shown), or other sensor signals. The second control section 270 generates control signals for controlling the turning on and off of the switching elements 221 in the driver circuit 220 for current feedback control. The control signals for current feedback control can be based, for example, on the mechanical angle θm2c, the detection values ​​of the current sensor (not shown), or other sensor signals. When the mechanical angles are used for current feedback control, the mechanical angles θm1c and θm2c are converted into electrical angles.

[0052] As it is in Fig. 5, the first control section 170 includes a signal acquisition unit 171, an absolute angle calculator 172, an abnormality determiner 175, and a communicator 179. The second control section 270 includes a signal acquisition unit 271, an absolute angle calculator 272, an abnormality determiner 275, and a communicator 279.

[0053] As described above, the first control section 170 and the second control section 270 may be microcontrollers, SoCs, or similar computers. The first control section 170 and the second control section 270 may also include specialized circuits such as ASICs or FPGAs. The elements of the signal acquisition unit 171, the absolute angle calculator 172, the abnormality determiner 175, and the communicator 179 in the first control section 170 may be implemented as specialized hardware circuits (e.g., ASICs, FPGAs) configured to perform the processes associated with the respective elements. Alternatively, the processes associated with the respective elements may be performed by the control section 170 as a microcontroller, wherein the signal acquisition unit 171, the absolute angle calculator 172, the abnormality determiner 175, and the communicator 179 implemented in Fig. 5 represent functional blocks or processes performed by the control section 170.

[0054] The same hardware / software implementation applies to the elements of the signal acquisition unit 271, the absolute angle calculator 272, the abnormality determiner 275, and the communicator 279 of the second control section 270. That is, the elements of the second control section may be implemented as specialized hardware circuits or may represent functional blocks of processes performed by the second control section 270 when these elements are implemented as software, hardware, or a software / hardware combination.

[0055] The signal acquisition unit 171 acquires the first output signal SGN1 from the first sensor section 130. The signal acquisition unit 271 acquires the second output signal SGN2 from the second sensor section 230. When the first system L1 is normal, the absolute angle calculator 172 calculates the absolute angle θa1 using the mechanical angle θm1c and the count value TC1. When the second system L2 is normal, the absolute angle calculator 272 calculates the absolute angle θa2 using the mechanical angle θm2c and the count value TC2. By converting the absolute angles θa1 and θa2 using the gear ratio of the reduction gear 89, a steering angle θs can be calculated. The steering angle θs is the rotation angle of the steering shaft 92. The absolute angles θa1 and θa2 can also be used to perform calculations other than the steering angle θs.

[0056] The abnormality determiner 175 can determine abnormalities in the first system L1 based on the result of comparing the mechanical angles θm1c and θm1e and the self-diagnosis result obtained by the first sensor section 130. The abnormality determiner 175 can also determine abnormalities in the first system L1 by comparing the absolute angles θa1 and θa2. The abnormality determiner 275 can determine abnormalities in the second system L2 based on the result of comparing the mechanical angles θm2c and θm2e and the self-diagnosis result obtained by the second sensor section 230. The abnormality determiner 275 can also determine abnormalities by comparing the absolute angles θa1 and θa2. The communicators 179 and 279 transmit the absolute angles θa1 and θa2 to each other as angle information.

[0057] While the self-diagnosis units 145 and 245 of the first and second systems L1 and L2 can monitor abnormalities in the sensor section 30 itself, the abnormality determiners 175 and 275 in the first and second control sections 170 and 270 can focus more on determining whether abnormalities in the absolute angles θa1 and θa2 exist by determining the underlying causes of the abnormalities of the absolute angles θa1 and θa2. For example, the abnormality determiners 175 and 275 can detect abnormalities in the absolute angles θa1 and θa2 and determine that these abnormalities are caused by signal noise, sensor errors, communication errors, or calculation errors. Such abnormalities generally result in calculation errors in the absolute angles θa1 and θa2. Detecting and determining by the abnormality determiners 175 and 275 may mean determining abnormalities in the calculation of the absolute angles θa1 and θa2.As described above, the abnormality determiners 175 and 275 can use abnormalities of the absolute angles θa1 and θa2 to determine abnormalities in the subject system (ie, the first system L1 or the second system L2).

[0058] In the present embodiment, the same calculations are performed in systems L1 and L2. When describing the calculation of the two systems, "1" and "2" may be used in the calculation references to distinguish between the first system L1 and the second system L2, respectively. As described above, the mechanical angles for control θm1c and θm2c may be used for various other calculations. In the description of various other calculations, the subscript "c" indicating "control" may be omitted. The same applies to the embodiments described later.

[0059] In the present embodiment, the count value TC and the mechanical angle θm are used to calculate an absolute angle θa. The absolute angle θa is an angle by which the motor 80 rotates with respect to a specific reference point or position. At time t1 in Fig. 6, for example, the absolute angle θa is 870° when the mechanical angle θm is 150° and a reference point of 0° is assumed. The absolute angle θa is 870° because the motor 80 has already rotated twice (i.e., by 720°) with respect to the reference point of 0°. The reference point can be a point other than 0°. The absolute angle θa can be calculated using equation (1) or equation (2). For calculation using equations (1) or (2), the example assumes a count value TC of 9 and a mechanical angle θm of 150°. θa=TC×90°+MOD(θm,90°)

[0060] In equation (1), MOD(θm, 90°) (where MOD is a modulus operation) means determining a remainder by dividing the mechanical angle θm by 90°. In this case, the remainder is equal to 60°, so that MOD(150°, 90°) is equal to 60°. Equation (1) can be described in such a way that, based on the count value TC, it is calculated how many revolutions have already been performed by determining in which of four ranges (as it is, for example, in Fig. 7) to determine where the rotation is currently located. More specifically, equation (1) calculates the range of the rotation position based on the mechanical angle θm. θa=DIV(TC / 4)×360°+θm

[0061] DIV(TC / 4) in equation (2) (where DIV is an integer division operation) represents a quotient obtained by dividing the count value TC by 4. In this example, where the count value TC is 9, DIV(9 / 4) would be 2. Equation (2) determines the number of revolutions the motor has made 80 revolutions based on the count value TC, and then further determines the current rotation position based on the mechanical angle θm with respect to the reference point. As described above, the calculation results of equations (1) and (2) are the same. That is, either equation (1) or equation (2) can be used to calculate the absolute angle θa.

[0062] In the present embodiment, the count value TC is counted based on the output of the comparator, which compares each of the "cos+" signal, the "sin+" signal, the "cos-" signal, and the "sin-" signal with a threshold value TH. The count value TC may be calculated by methods other than (i) a mutual comparison of the output "cos+" signal, the "sin+" signal, the "cos-" signal, and the "sin-" signal, and / or (ii) a threshold comparison using a logical operation of the output "cos+" signal, the "sin+" signal, the "cos-" signal, and the "sin-" signal.

[0063] During counting of the count value TC, the count value TC may deviate from the true or actual count value TC due to deviations of the threshold value TH or sensor signal errors. As described in Fig. As shown in Figure 7, uncertain ranges "Ri" can be referred to as ranges in which the counting value can be incremented or decremented. The uncertain range Ri is a range in which the counting value TC can deviate from an actual, true value depending on whether the counting value TC has already been incremented or decremented. The safe ranges "Rd" (e.g., Rd0, Rd1) are ranges in which the counting value TC can be definitely determined, and the counting value cannot be incremented or decremented. Fig. In Figure 7, the unsafe areas Ri are shown with dotted hatching. The safe area within area R0 is denoted as Rd0, the safe area within area R1 is denoted as Rd1, the safe area within area R2 is denoted as Rd2, and the safe area within area R3 is denoted as Rd3.

[0064] In the present embodiment, the absolute angle calculation, as calculated from equation (1) or equation (2) using the mechanical angle θm and the count value TC in the safe range Rd, is performed by the absolute angle calculator 172 and 272 immediately after the vehicle is turned on (i.e., immediately after the ignition switch or start switch of the vehicle is turned on). In the second and subsequent calculations, the absolute angle θa is calculated by adding a difference between the values ​​of the mechanical angle θm. More specifically, the absolute angle calculator 172 calculates the current absolute angle θa(n) based on the previous value of the absolute angle θa(n-1) and the change amount of the mechanical angle θm, i.e., the difference between a current value of the mechanical angle θm(n) and the previous value of the mechanical angle θm(n-1).The second and subsequent calculations of the absolute angle θa can be calculated using equation (3). The absolute angle θa can be stored in a memory for use in the second and subsequent calculations using equation (3). That is, the calculated absolute angle θa can be continuously updated and stored in a memory for use as the previous absolute angle θa(n - 1) to be used in calculating the current absolute angle θa. The absolute angle θa can be calculated by adding the mechanical angle difference to the previously calculated absolute angle. In equation (3), the subscript (n) denotes the current value, while the subscript (n - 1) denotes the previous value. θa(n)=θa(n−1)+(θm(n)−θm(n−1))

[0065] The absolute angle calculation process of the present embodiment will be explained with reference to the flowchart of Fig. 8. The absolute angle calculation process is performed by the absolute angle calculators 172 and 272 with a predetermined cycle. The absolute angle calculation processes of the absolute angle calculators 172 and 272 are similar to each other. That is, if the values ​​of the first system L1 and the values ​​of the second system L2 were exchanged, the absolute angle calculator 172 would perform the same calculations with the values ​​of the second system L2 as the absolute angle calculator 272. The process described in Fig. 8 is described with reference to the absolute angle calculator 172 and the first system L1, but the process can also be used for the absolute angle calculator 272 and the second system L2.

[0066] In S101, the absolute angle calculator 172 determines whether the first system L1 (i.e., the subject system) was normal during the previous calculation. If the absolute angle calculator 172 determines that the subject system was abnormal during the previous calculation, i.e., if "No" is determined in S101, the process proceeds to S104. If the absolute angle calculator 172 determines that the subject system was normal during the previous calculation, i.e., if "Yes" is determined in S101, the process proceeds to S102.

[0067] In S102, the absolute angle calculator 172 determines whether the subject system is normal during the current calculation. If the absolute angle calculator 172 determines that the subject system is abnormal during the current calculation, i.e., if "No" is in S102, the process proceeds to S105. If the absolute angle calculator 172 determines that the subject system is normal during the current calculation, i.e., if "Yes" is in S102, the process proceeds to S103. In S103, the absolute angle calculator 172 calculates the absolute angle θa1 using equation (3) with the values ​​of the subject system measured and calculated during normal operation of the subject system (i.e., normal values). The count value TC1, the mechanical angle θm1, and the calculated absolute angle θa1 are stored in a memory such as a RAM as normal values.

[0068] The stored normal values ​​are set as hold values, such as a count hold value TC1_hold, a mechanical angle hold value θm1_hold, and an absolute angle hold value θa1_hold. Some of the values ​​to be stored in the memory (i.e., the hold values) may be omitted depending on the abnormality treatment procedure and the recovery procedure.

[0069] In S104, the absolute angle calculator 172 determines, similarly to S102, whether the subject system is normal during the current calculation. If the absolute angle calculator 172 determines that the subject system is abnormal, ie, if S104 is "No," the process proceeds to S105. If the absolute angle calculator 172 determines that the subject system is normal, ie, if S104 is "Yes," the process proceeds to S106.

[0070] In S105, the absolute angle calculator 172 performs an abnormality handling procedure. In the abnormality handling procedure, the absolute angle calculator uses the absolute angle hold value θa1_hold stored in the memory as the absolute angle θa1. The absolute angle hold value θa1_hold stored in the memory before the abnormality detection is kept unchanged. Alternatively, the absolute angle calculator 172 may use the absolute angle θa2 from the other system (ie, the second system L2) as the absolute angle θa1 if the other system is normal.

[0071] In S106, the absolute angle calculator 172 calculates an absolute recovery angle θa1_r as a recovery procedure. In the present embodiment, the absolute recovery angle θa1_r is derived by adding a mechanical angle change amount Δθm1 to the absolute angle hold value θa1_hold, as shown in equation (4). The mechanical angle change amount Δθm1 is the amount of change in the mechanical angle θm1 during abnormality detection. The mechanical angle change amount Δθm1 is derived by subtracting a mechanical angle hold value θm1_hold in the memory from the mechanical recovery angle θm1_r, as shown in equation (5).The mechanical angle hold value θm1_hold is the mechanical angle stored in the memory before the abnormality detection, and the mechanical recovery angle θm1_r is the mechanical angle measured or calculated when the subject system has recovered to a normal state after the abnormality occurrence. θa1_r=θa1_hold+Δθm1 Δθm1=θm1_r−θm1_hold

[0072] The time diagram of the Fig. Figure 9 shows an example of an abnormality occurring in the subject system at time t1 and a recovery of the subject system from the abnormality at time t2. In Fig. 9, the horizontal axis in the time chart represents time, and the vertical axis represents angle. When an abnormality occurs at time t1, the normal absolute angle θa1 and the normal mechanical angle θm1 are stored as the absolute angle hold value θa1_hold and the mechanical angle hold value θm1_hold, respectively. Fig. 9, the normal time of the subject system is the time until the time t1 at which the abnormality occurs. During the abnormality treatment procedure, the absolute angle calculator 172 continuously uses the absolute angle hold value θa1_hold as the absolute angle θa1 during the period from the time t1 to the time t2. Alternatively, if the absolute angle calculator 172 uses the absolute angle θa2 as the absolute angle θa1 during the occurrence of the abnormality, the value of the absolute angle θa2 in Fig. 9 from time t1 to time t2 is shown as a dot-dash line. Although the absolute angle θa2 can be used instead of the absolute angle hold value θa1 for the absolute angle θa1 during the occurrence of the abnormality in the subject system, when using the absolute angle θa2, it is assumed that there are no inter-system errors between the systems L1 and L2, and that the other system (ie, the second system L2) is operating normally.

[0073] When the subject system returns to the normal state at time t2, the absolute angle calculator 172 calculates the absolute recovery angle θa1_r using equation (4). After the subject system has recovered from the abnormality at time t2, the absolute angle calculator 172 calculates the absolute angle θa1 using the normal procedure (for example, using equation (3)). That is, the absolute angle calculator 172 resumes normal absolute angle calculation. Thus, if the change in the rotation angle (for example, Δθm1) from abnormality detection to recovery is less than 180°, the absolute angle calculator 172 can calculate the absolute angle θa1 in the post-recovery period (for example, after time t2) with the same accuracy as in the absolute angle calculations before the abnormality occurred (for example, before time t1). That is,, the post-recovery calculation accuracy of the absolute angle calculation is the same as the pre-abnormality calculation accuracy.

[0074] As described above, the ECU 10 configured as the rotation detection device of the present embodiment includes the sensor sections 130 and 230 and the control sections 170 and 270. The sensor sections 130 and 230 detect the rotation of the motor 80 and output rotation information regarding the mechanical angles θm1 and θm2 and the number of revolutions of the motor. The mechanical angles θm1 and θm2 may also be referred to as "rotation angles" and "first rotation information." Second rotation information may refer to the count values ​​TC1 and TC2.

[0075] The control sections 170 and 270 include the signal acquisition units 171 and 271, the absolute angle calculators 172 and 272, the abnormality determiners 175 and 275, and the communicators 179 and 279. The signal acquisition units 171 and 271 acquire the mechanical angles θm1 and θm2 and the count values ​​TC1 and TC2 from the sensor sections 130 and 230. The absolute angle calculators 172 and 272 calculate the absolute angles θa1 and θa2, which are the rotation quantities with respect to the reference position, based on the mechanical angles θm1 and θm2 and the count values ​​TC1 and TC2. The abnormality determiners 175 and 275 determine abnormalities of the absolute angles θa1 and θa2. In other words, the abnormality determiners 175 and 275 determine whether the absolute angles θa1 and θa2 are abnormal.Abnormalities of the absolute angles θa1 and θa2 may include abnormalities of the values ​​used to calculate the absolute angles θa1 and θa2, such as abnormalities of the mechanical angles θm1 and θm2 and abnormalities of the count values ​​TC1 and TC2. Communicators 179 and 279 transmit and receive absolute angle information regarding the absolute angles θa1 and θa2.

[0076] When abnormalities occur in the absolute angle θa1, the absolute angle calculator 172 uses the absolute angle hold value θa1_hold stored in the memory. The absolute angle hold value θa1_hold is a value of the absolute angle θa1 calculated during the normal time before the abnormality detection and stored in the memory. When the abnormalities in the absolute angle θa1 are eliminated and resolved, and the absolute angle θa1 and the subject system (ie, L1) have recovered to the normal state, the absolute angle calculator 172 returns to the normal absolute angle calculation after calculating the absolute recovery angle θa1_r.

[0077] The control section 170 and the sensor section 130 are combined to calculate the absolute angles in the first system L1, and the control section 270 and the sensor section 230 are combined to calculate the absolute angles in the second system L2. The absolute angle in one subject system is referred to as the subject-system absolute angle, and the absolute angle obtained from the other system is referred to as the other-system absolute angle. In the example described above, it is assumed that the first system L1 is the subject system, in which the subject-system absolute angle is the absolute angle θa1 and the other-system absolute angle is the absolute angle θa2.When an abnormality occurs in the absolute angle θa1, the absolute angle calculator 172 uses (i) the absolute angle hold value θa1_hold stored in a memory before the abnormality detection as the value for the absolute angle θa1 or (ii) alternatively, the other-system absolute angle θa2 obtained from the other system as the value for the absolute angle θa1.

[0078] As a result of using the alternative absolute angle values, the rotation detection device 10 of the present embodiment can calculate the absolute angle θa1 without interruption even when abnormalities occur. Furthermore, the rotation detection device 10 of the present embodiment can appropriately recover from an abnormal state by calculating the absolute recovery angle θa1_r. In this way, the rotation detection device 10 is able to recover from temporary absolute angle abnormalities that may be caused by communication errors and signal noise between the sensor sections 130 and 230 and the control sections 170 and 270.

[0079] In the present embodiment, the absolute angle calculator 172 calculates the absolute recovery angle θa1_r based on (i) the absolute angle hold value θa1_hold and (ii) the mechanical angle change amount Δθm1. The absolute angle calculator 272 can calculate the absolute recovery angle θa2_r in the second system L2 in a similar manner.

[0080] The electric power steering device 8 includes the ECU 10 and the motor 80, which outputs an assist torque to assist a steering operation of the vehicle. Since the absolute angle θa is calculated by the ECU 10 of the present embodiment, the ECU 10 can calculate the steering angle by converting the absolute angle θa with the gear ratio of the reduction gear 89 that transmits the output of the motor 80 to the steering system 90. In this way, the ECU 10 functions as a steering angle sensor, and the electric power steering device 8 including the ECU 10 of the present embodiment can dispense with a steering angle sensor. Since the ECU 10 can appropriately calculate the absolute angle θa during abnormalities, the ECU 10 can also calculate the steering angle during abnormalities. (Second embodiment not according to the invention)

[0081] The second embodiment will be described with reference to Fig. 10 described.

[0082] The second, third, fourth, and fifth embodiments describe recovery procedures that differ from the recovery procedure of the first embodiment. The descriptions of the second, third, fourth, and fifth embodiments focus primarily on the differences in the recovery procedure. Unless otherwise stated, the structural elements, components, features, and arrangements of the second, third, fourth, and fifth embodiments may be the same as those of the first embodiment, as shown, for example, in the Fig. 1 to 5 and described with reference thereto. Like elements, components, and features in the following embodiments may be denoted by the same reference numerals as in the first embodiment, and repeated description of the previously described like elements, components, and features may be omitted for the following embodiments. Similar to the description of the first embodiment, the following embodiments describe calculations in the first system L1 and omit a description of the calculations in the second system L2. In the following embodiments, the calculations for the first system L1 may be applied to the second system L2 in a similar manner using values ​​calculated and measured by the second system L2 or values ​​supplied from the first system L1.

[0083] In the Fig. 10, Fig. 11, Fig. 12 and Fig. 13, the procedure up to time t2 is the same as the procedure up to time t2 in the first embodiment as described with reference to Fig. 9 was described.

[0084] In the present embodiment, for the recovery procedure from time t2, the absolute angle calculator 172 uses the recovery count TC1_r and the mechanical recovery angle θm1_r to recalculate the absolute angle. That is, the absolute angle calculator 172 calculates the absolute recovery angle θa1_r at time t2 using equation (1) or (2), substituting the recovery counts for the corresponding values ​​in equations (1) and (2) (for example, the mechanical recovery angle θm1_r is used instead of the mechanical angle θm). The control section 170 can compare the absolute recovery angle θa1_r and the absolute angle θa2 of the second system to determine whether the absolute recovery angle θa1_r and the absolute angle θa2 are equal.The equality of the absolute recovery angle θa1_r and the absolute angle θa2 indicates "normal" to the control section 170, indicating that recovery from the abnormality at time t2 can be properly performed. The control section 170 can then calculate the absolute angle θa1 by adding the change amount of the mechanical angle θm1 to the absolute recovery angle θa1_r. By using such a configuration, the control section 170 can continue calculating the absolute angle θa1 after recovery to the normal state with the same accuracy as before the abnormality detection.

[0085] In the present embodiment, the absolute angle calculator 172 calculates the absolute angle θa1 based on the mechanical angle θm1 and the count value TC1 in the first calculation, and then calculates the absolute angle θa1 based on the value from the first calculation and the mechanical angle θm1 in subsequent calculations. After an abnormality is detected and the abnormality is resolved, the absolute angle θa1 is recalculated using the mechanical angle θm1 and the count value TC1 in the same way as in the first calculation, and the recalculated absolute angle θa1 is used as the absolute recovery angle θa1_r. In this way, the control section 170 and the absolute angle calculator 172 can use the recovery procedure described above to appropriately calculate the absolute recovery angle θa1_r. Such a recovery procedure can also be used for and by the second system L2.The present embodiment achieves the same advantageous effects as the previous embodiment. (Third embodiment not according to the invention)

[0086] The third embodiment is in Fig. 11 shown. In Fig. 11, for the recovery procedure from time t2, the absolute angle θa2 of the second system is used as the absolute recovery angle θa1_r of time t2. The change amount of the mechanical angle θm1 is then added to the absolute recovery angle θa1_r in subsequent calculations to calculate the absolute angle θa1. In the present embodiment, the absolute recovery angle θa1_r is set as the absolute angle θa2 of the second system. The control section 170 of the present embodiment does not perform inter-system comparison, making it possible to shorten the time for the recovery procedure.

[0087] In the present embodiment, the absolute angle calculator 172 sets the absolute angle θa2 of the other system at the recovery time as the absolute recovery angle θa1_r. In this way, the control section 170 and the absolute angle calculator 172 can appropriately set the absolute recovery angle θa1_r. Such a configuration achieves the same advantageous effects as the previous embodiments. (Fourth embodiment not according to the invention)

[0088] The fourth embodiment is in Fig. 12 shown. In Fig. 12, in the recovery procedure, the absolute angle calculator 172 calculates the absolute recovery angle θa1_r at time t2 based on the absolute angle hold value θa1_hold of the subject system and an absolute angle difference value Δθa2 of the other system, as shown in equation (6). The absolute angle difference value Δθa2 is a difference value between the absolute angle hold value θa2_hold calculated when the other system L2 is normal (ie, at a normal time) and the absolute recovery angle θa2_r, as shown in equation (7). θa1_r=θa1_hold+Δθa2 Δθa2=θa2_r−θa2_hold

[0089] With such a configuration, control sections 170 and 270 do not perform inter-system comparison, which shortens the recovery time compared to other embodiments. Furthermore, since the value from the other system is a differential value, the influence of inter-system errors caused by, for example, detection errors, communication delays, and signal noise is prevented or at least reduced.

[0090] In the present embodiment, the absolute angle calculator 172 calculates the absolute recovery angle θa1_r based on (i) the absolute angle hold value θa1_hold, which is the absolute angle of the subject system before abnormality detection, and (ii) the absolute angle difference value Δθa2, which is the difference between two absolute angle hold values ​​θa2_hold in the other system between that before abnormality detection and that at the recovery time. With such a configuration, the control section 170 and the absolute angle calculator 172 can appropriately calculate the absolute recovery angle θa1_r. Such a recovery procedure can also be used for and by the second system L2. The present embodiment achieves the same advantageous effects as the previous embodiments. (Fifth embodiment of the invention)

[0091] The fifth embodiment is in Fig. 13 shown. In Fig. 13, the absolute angle calculator 172 calculates the absolute recovery angle θa1_r based on (i) the absolute angle hold value θa1_hold of the subject system and (ii) an angle correction value A of the subject system. The absolute angle calculations of the recovery procedure performed by the absolute angle calculator 172 at time t2 are given by the following equations (8) and (9). θa1_r=θa1_hold+A A=DIV{Δθa2 / 360}×360+(θm1_r-θm1_hold)

[0092] With such a configuration, the control sections 170 and 270 do not perform inter-system comparison, making it possible to shorten the time required to perform the recovery procedure. Since the angle correction is derived by dividing the absolute angle difference value Δθa2 of the other system L2 by 360, the number of revolutions N is extracted from the absolute angle θa2 of the other system during the abnormality treatment of the subject system L1. The absolute angle calculator 172 can calculate the absolute angle θa1 after recovery with the same calculation accuracy as in the absolute angle calculations before the abnormality occurred, because the number of revolutions N has a low susceptibility to an inter-system error.

[0093] In the present embodiment, the absolute angle calculator 172 calculates the absolute recovery angle θa1_r based on (i) the absolute angle hold value θa1_hold, which is the absolute angle of the subject system L1 before the abnormality detection, (ii) the absolute angle difference value Δθa2, which is the difference of the absolute angles in the other system L2 between (a) before the abnormality detection and (b) at the recovery time, and (iii) the mechanical angle change amount Δθm1, which is the difference of the mechanical angles in the subject system L1 between (a) before the abnormality detection and (b) at the recovery time.Specifically, the absolute angle calculator 172 calculates the absolute recovery angle θa1_r based on (i) the absolute angle hold value θa1_hold of the subject system L1, (ii) a revolution number conversion value of the other system L2 based on the absolute angle difference value L1Sa2, and (iii) the mechanical angle change amount Δθm1 in the subject system L1. By employing such a configuration, the control section 170 and the absolute angle calculator 172 can appropriately calculate the absolute recovery angle θa1_r. Such a recovery procedure can also be used for and by the second system L2. The present embodiment achieves the same advantageous effects as the previous embodiments. (Other embodiments)

[0094] In the embodiments described above, the first rotation information is a mechanical angle, and the second rotation information is a count value. In other embodiments, the first rotation information may be any value that can be converted into a mechanical angle. In other embodiments, the second rotation information may be any value that can be converted into the number of revolutions. In the embodiments described above, one revolution is divided into four ranges, and the count value for one revolution of the motor is four. In other embodiments, one revolution may be divided into a different number of ranges, such as three, five, or more ranges. In other embodiments, the mechanical angle may be corrected by an offset correction.Displacement correction must be corrected to avoid the change position of the mechanical angle from 360° to 0° being located within an unsafe range.

[0095] In the embodiments described above, two sensor sections and two control sections are arranged for a dual-system configuration. In other embodiments, the number of systems may be three or more, or one. Multiple sensor sections may be arranged for one control section. In such a case, the absolute angle calculator may be arranged internally for each sensor section, and the combination of the sensor section and the absolute angle calculator may be considered a "system."

[0096] In the embodiments described above, electrical power is supplied to the first sensor section and the second sensor section from two separate batteries, and an output signal from two sensor sections is transmitted to two separate control sections. In other embodiments, electrical power may be supplied from a single battery to multiple sensor sections. In such a case, a power source, such as a regulator, may be arranged for each sensor section or may be shared between the sensor sections. In other embodiments, multiple sensor sections may each transmit an output signal to a single control section.

[0097] In other embodiments, the absolute angle information may be any value that can be converted into an absolute angle. Since the steering angle detected by the steering angle sensor can be converted into the absolute angle by the gear ratio of the reduction gear, for example, the steering angle information regarding the steering angle can be used as absolute angle information. In other words, the other-system absolute angle is not necessarily limited to internal information obtained from within the rotation detection device, but may also be obtained from outside the rotation detection device (e.g., a value obtained externally).

[0098] In the embodiments described above, the sensor section is a sensing element that detects a change in the magnetic field of the magnet. In other embodiments, other rotation angle detection methods and devices, such as a resolver or an inductive sensor, may be used. Furthermore, a communicator may be arranged to transmit respective types of information. For example, a first communicator may be arranged to transmit the first rotation information, and a second communicator may be arranged to transmit the second rotation information.

[0099] In the embodiments described above, the revolution number calculation is not performed based on the signal from the magnetic field detection unit for abnormality detection. In other embodiments, the revolution number calculation may be performed based on the signal from the magnetic field detection unit for abnormality detection, and the calculation result may be transmitted to the control section. In this way, the inter-system correction and / or the abnormality monitoring by inter-system comparison can be omitted for the second system.

[0100] In the embodiments described above, the motor is a brushless three-phase motor. In other embodiments, the motor is not limited to a permanent magnet type brushless three-phase motor, but can be implemented as any type of motor. The motor can also be a generator or a motor-generator that has both a motor function and a generator function. Therefore, the electric rotary machine is not necessarily limited to a motor, but can be a motor, a generator, or a motor-generator.

[0101] In the embodiments described above, a control device including the rotation detection device is used for an electric power steering device. In other embodiments, the control device including the rotation detection device may be used for devices other than an electric power steering device.

Claims

[1] Rotation detection device comprising: a sensor section (130, 230) configured to detect a rotation of a motor (80) and output first rotation information including a rotation angle of the motor within one revolution of the motor and second rotation information including a number of revolutions of the motor; and a control section (170, 270) containing: a signal obtaining device (171, 271) configured to obtain the first rotation information and the second rotation information from the sensor section; an absolute angle calculator (172, 272) configured to calculate an absolute angle indicating a rotation amount with respect to a reference position based on the first rotation information and the second rotation information; an abnormality determiner (175, 275) configured to determine an abnormality in a calculation of the absolute angle; and a communicator (179, 279) configured to transmit and receive absolute angle information for the absolute angle, wherein the absolute angle calculator, in response to the abnormality in the calculation of the absolute angle, is further configured to use a pre-abnormality value of the absolute angle to calculate the absolute angle, wherein the pre-abnormality value of the absolute angle is calculated before the abnormality in the calculation of the absolute angle occurs, the absolute angle calculator is further designed to recover from the abnormality of the calculation of the absolute angle after an absolute recovery angle has been calculated and to resume a normal absolute angle calculation, the sensor section and the control section are combined as one system and the rotation detection device contains at least two sensor section and control section systems, the absolute angle is called either a subject-system absolute angle, if the absolute angle is calculated by a subject system, or an other-system absolute angle, if the absolute angle is calculated by a system other than the subject system, the absolute angle calculator is further configured, in response to the abnormality in the calculation of the absolute angle, to use either the pre-abnormality value of the absolute angle to calculate the absolute angle or the other-system absolute angle to calculate the absolute angle, and the absolute angle calculator is further configured to calculate the absolute recovery angle based on (i) the pre-abnormality absolute angle of the subject system (θa1_hold), (ii) a difference (Δθa2) between the pre-abnormality absolute angle of the other system and the absolute recovery angle of the other system, and (iii) a difference (θm1_r - θm1_hold) between the pre-abnormality absolute angle of the subject system and the recovery rotation angle of the subject system. [2] Electric power steering device comprising: the rotation detecting device according to claim 1, and the motor for outputting a steering torque for a steering operation of a vehicle.

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