JP2020079058A - Angle calculation device and steering apparatus - Google Patents

Abstract

To provide an angle calculation device capable of improving reliability of calculation of an absolute angle; and to provide a steering apparatus.SOLUTION: A first operational circuit includes a counter BIST part for diagnosing a counter abnormality detection part, and a power supply BIST part for diagnosing a voltage abnormality detection part. A second operational circuit includes a first absolute angle information BIST part for diagnosing a first absolute angle information abnormality detection part, and a second absolute angle information BIST part for diagnosing a second absolute angle information abnormality detection part. A third operational circuit includes an absolute angle BIST part for diagnosing an absolute angle abnormality detection part. Execution timings of diagnosis by each BIST part (the counter BIST part, the power supply BIST part, the first absolute angle information BIST part, the second absolute angle information BIST part and the absolute angle BIST part) are different mutually.SELECTED DRAWING: Figure 7

Description

  The present invention relates to an angle calculation device and a steering device.

  Conventionally, a so-called steer-by-wire type steering device in which power transmission between a steering wheel and steered wheels is separated is known. For example, the steering device of Patent Document 1 has a clutch that intermittently transmits power between a steering wheel and steered wheels, a reaction force motor that is a source of a steering reaction force applied to a steering shaft, and a steering wheel that steers the steered wheels. It has a steering motor that is the source of the rudder force. Further, the steering device of Patent Document 1 has a control device that controls the operations of the clutch, the reaction force motor, and the steering motor.

  When the vehicle is traveling, the control device releases the clutch to disconnect the power transmission between the steering wheel and the steered wheels. The control device controls the steering motor so that the actual steering angle of the steered wheels follows the target steering angle, and also the reaction motor to generate the steering reaction force according to the steered state of the steered wheels. Control. The target turning angle is calculated based on the steering angle detected by the steering angle sensor. The steered state is detected by a steered angle sensor. Both the steering angle sensor and the steering angle sensor are absolute angle sensors.

  The above control device controls the reaction force motor by using the rotation angle detected by the first rotation angle sensor provided in the reaction force motor, and detects it by the second rotation angle sensor provided in the steering motor. The steering angle is controlled to control the steering motor. Both the first rotation angle sensor and the second rotation angle sensor are relative angle sensors. The first rotation angle sensor acquires the midpoint of the steering angle, which is a reference point for sensing, through the steering angle sensor. The second rotation angle sensor acquires the midpoint of the turning angle, which is a reference point for sensing, through the turning angle sensor. The control device described above uses the midpoint of the turning angle acquired through the turning angle sensor, and based on the rotation angle detected through the second rotation angle sensor, the actual turning of the steered wheels indicated by the absolute angle. The angle is calculated.

JP, 2016-545, A

  The above control device controls the steering motor using the actual steering angle obtained by the calculation. Therefore, higher reliability is required for the calculation of the actual turning angle by the control device.

  An object of the present invention is to provide an angle calculation device and a steering device that can improve the reliability of calculation of an absolute angle.

  An angle calculation device capable of achieving the above object is a value for calculating an integrated angle obtained by integrating the relative angle of the motor based on the detection result of the first sensor that detects the relative angle of the motor that is the power source of the mechanical device. A first arithmetic circuit having a counter section for calculating a count value, a first abnormality detecting section for detecting an abnormality of the counter section, and a first BIST section for diagnosing the first abnormality detecting section; and the mechanical device. An absolute position information calculation unit that calculates absolute position information that is a value for calculating the absolute position of the detection target based on the detection result of the second sensor that detects the absolute position of the detection target that interlocks with the motor; A second arithmetic circuit having a second abnormality detecting section for detecting abnormality of the absolute position information calculating section and a second BIST section for diagnosing the second abnormality detecting section; and calculating the integrated angle using the count value. And an absolute angle calculation unit that calculates an absolute angle of a rotary shaft that is interlocked with the motor using the absolute position information, and the first calculation circuit based on a comparison between the integrated angle and the absolute angle. And a third operation unit having a third error detection unit that detects an error in at least one of the second operation circuits, and a third BIST unit that diagnoses the third error detection unit, the first BIST unit, the The diagnostic execution timings of the second BIST unit and the third BIST unit are different from each other.

  Here, after executing the diagnosis of the abnormality detecting unit by the BIST unit, the operating state of the angle calculation device including the abnormality detecting unit that is the diagnosis target is set to the state in which the abnormality is detected. In order to cancel the detected state and return to the operating state in which the absolute angle of the rotary shaft interlocking with the motor can be calculated, it is necessary to reset the state in which the abnormality is detected.

  When the diagnosis of the plurality of abnormality detecting units by the plurality of BIST units has to be executed as in the above configuration, while the diagnosis by any of the BIST units is being executed, the diagnosis by the other BIST unit is performed. When the operating state of the angle calculation device is reset, the diagnosis result may not be obtained correctly.

  In this respect, according to the above configuration, since the execution timing of the diagnosis of each BIST unit is different from each other, the operation of the angle calculation device is performed according to the execution of the diagnosis by another BIST unit during the execution of the diagnosis by each BIST unit. It is possible to suppress the occurrence of a situation where the state is reset. As a result, the reliability of the diagnosis of the abnormality detecting unit targeted by each BIST unit can be improved. Therefore, the reliability of the calculation of the absolute angle by the angle calculation device can be improved.

  Further, similarly to the above, when the operation state of the angle calculation device is reset with the execution of the diagnosis by the BIST unit at the sampling timing of the detection results by the first sensor and the second sensor, the first sensor and the second sensor Sampling of detection results by may not be performed correctly.

  In order to cope with this, it is preferable that the execution timing of the diagnosis by the first BIST unit, the second BIST unit, and the third BIST unit be different from the sampling timing of the detection result by the first sensor and the second sensor.

  According to the above configuration, since the execution timing of the diagnosis by each BIST unit is different from the sampling timing of the detection result by the first sensor and the second sensor, the angle calculation is performed along with the execution of the diagnosis by the BIST unit at the sampling timing. It is possible to suppress the occurrence of a situation in which the operating state of the device is reset. As a result, the reliability of sampling the detection results of the first sensor and the second sensor can be improved.

  It should be noted that the integrated angle and the absolute angle used when the third abnormality detection unit detects an abnormality are changed according to the operation of the motor. Therefore, changes in the integrated angle and the absolute angle are related to each other.

  That is, in the above angle calculation device, the third abnormality detection unit uses the amount of change in the integrated angle per unit time and the amount of change in the absolute angle per unit time, An abnormality of at least one of the second arithmetic circuits can be detected.

  In a steering device including the above angle calculation device and a steering unit as the mechanical device, the steering unit is a steering shaft that steers the steered wheels by performing linear motion, and a steering shaft that bites the steering shaft. A combined pinion shaft, a steering motor that is a source of power generated by the steering shaft, and a transmission mechanism that transmits the power generated by the steering motor to the steering shaft, The detection target is the pinion shaft provided so as to interlock with the steering motor.

  According to the above configuration, since the steered system includes the above angle calculation device, when it is necessary to obtain the absolute angle of the pinion shaft from the detection result of the first sensor and the detection result of the second sensor, It is possible to realize a steering device that can improve the reliability of the calculated absolute angle of the pinion shaft.

  According to the present invention, the reliability of the calculation of the absolute angle by the angle calculation device and the steering device can be improved.

1 is a schematic configuration diagram of a steering device in which an embodiment of an angle calculation device and a steering device is mounted. The block diagram which shows a steering control part. The block diagram which shows a 1st arithmetic circuit. The block diagram which shows a 2nd arithmetic circuit. The block diagram which shows a 3rd arithmetic circuit. The graph which shows the relationship between the 1st absolute angle information, the 2nd absolute angle information, and the absolute angle of a 1st pinion shaft. The figure which shows the relationship between the execution timing of the diagnosis by each BIST part, and sampling timing.

An embodiment in which the angle calculation device and the steering device are mounted on a steer-by-wire type steering device will be described below.
As shown in FIG. 1, a vehicle steering system 10 has a steering shaft 12 connected to a steering wheel 11. A first pinion shaft 13 is provided at an end of the steering shaft 12 opposite to the steering wheel 11. The first pinion teeth 13 a of the first pinion shaft 13 are meshed with the first rack teeth 14 a of the steered shaft 14 extending in a direction intersecting with the first pinion shaft 13. Left and right steered wheels 16 and 16 are connected to both ends of the steered shaft 14 via tie rods 15 and 15, respectively.

The steering device 10 has a clutch 21 and a clutch control unit 22.
The clutch 21 is provided in the middle of the steering shaft 12. As the clutch 21, an electromagnetic clutch is used that connects and disconnects power by connecting and disconnecting power to the exciting coil. When the clutch 21 is disengaged, power transmission between the steering wheel 11 and the steered wheels 16, 16 is disengaged. When the clutch 21 is connected, power transmission between the steering wheel 11 and the steered wheels 16, 16 is connected.

  The clutch control unit 22 controls engagement/disengagement of the clutch 21. The clutch control unit 22 switches the clutch 21 from the connected state to the disconnected state by energizing the exciting coil of the clutch 21. Further, the clutch control unit 22 switches the clutch 21 from the disengaged state to the connected state by stopping energization of the exciting coil of the clutch 21.

  When the clutch 21 is engaged, the steering shaft 12, the first pinion shaft 13, and the steered shaft 14 function as a power transmission path between the steering wheel 11 and the steered wheels 16, 16. That is, the turning angle θt of the steered wheels 16 and 16 is changed by the linear movement of the steered shaft 14 in accordance with the rotation operation of the steering wheel 11.

  The steering device 10 includes a reaction force motor 31, a first reduction mechanism 32, a first rotation angle sensor 33, a torque sensor 34, and a reaction force control unit 35 as a configuration for generating a steering reaction force. The steering reaction force is a force (torque) acting in a direction opposite to the direction in which the driver operates the steering wheel 11. By applying the steering reaction force to the steering wheel 11, it is possible to give the driver an appropriate feeling of response.

  The reaction force motor 31 is a source of a steering reaction force. As the reaction force motor 31, for example, a three-phase (U-phase, V-phase, W-phase) brushless motor is adopted. The rotation shaft of the reaction force motor 31 is connected to the steering shaft 12 via the first reduction mechanism 32. The first reduction gear mechanism 32 reduces the rotation of the reaction force motor 31, and transmits the reduced rotation force to the steering shaft 12. The first reduction gear mechanism 32 is provided on a portion of the steering shaft 12 closer to the steering wheel 11 than the clutch 21. The torque of the reaction force motor 31 is applied to the steering shaft 12 as a steering reaction force.

  The first rotation angle sensor 33 is provided on the reaction force motor 31. The first rotation angle sensor 33 is a relative angle sensor that detects the rotation angle of the rotation shaft of the reaction force motor 31 in the range of 0 degrees to 360 degrees. The first rotation angle sensor 33 generates an electric signal Sa according to the rotation angle θa of the rotation shaft of the reaction force motor 31. As the first rotation angle sensor 33, for example, an MR sensor (magnetoresistive effect sensor) which is a kind of magnetic sensor is adopted. The MR sensor generates an electric signal Sa according to the magnetic field direction of a bias magnet having a pair of magnetic poles (N pole, S pole) provided at the end of the output shaft of the steering motor 41. The electrical signal Sa is a sine wave signal Ssin that changes sinusoidally with respect to the rotation angle θa of the rotation shaft of the reaction force motor 31, and a cosine wave that changes cosine wave with respect to the rotation angle θa of the rotation shaft of the reaction force motor 31. It contains the wave signal Scos. Each of the sine wave signal Ssin and the cosine wave signal Scos is a signal in which one period is a period in which the steering motor 41 rotates by an angle (here, 360 degrees) corresponding to one magnetic pole pair of the bias magnet.

  The torque sensor 34 detects the steering torque Th applied to the steering shaft 12 through the rotating operation of the steering wheel 11. The torque sensor 34 is provided in a portion of the steering shaft 12 closer to the steering wheel 11 than the first reduction gear mechanism 32.

  The reaction force control unit 35 executes reaction force control for generating a steering reaction force according to the steering torque Th through drive control of the reaction force motor 31. The reaction force control unit 35 calculates the target steering reaction force based on the steering torque Th detected by the torque sensor 34 and the vehicle speed V detected by the vehicle speed sensor 36, and based on the calculated target steering reaction force. The target steering angle θ* of the steering wheel 11 is calculated. The reaction force control unit 35 outputs the calculated target steering angle θ* to the steering control unit 47. The reaction force control unit 35 calculates the rotation angle θa of the reaction force motor 31 based on the electric signal Sa generated by the first rotation angle sensor 33, and the actual steering of the steering wheel 11 based on the calculated rotation angle θa. The angle θs is calculated. The reaction motor 31 and the steering shaft 12 are interlocked with each other via the first reduction gear mechanism 32. Therefore, there is a correlation between the rotation angle θa of the rotation shaft of the reaction force motor 31 and the rotation angle of the steering shaft 12. There is also a correlation between the rotation angle of the steering shaft 12 and the steering angle θs that is the rotation angle of the steering wheel 11. Therefore, the steering angle θs can be obtained based on the rotation angle θa of the rotation shaft of the reaction force motor 31. The reaction force control unit 35 calculates the steering angle θs of the steering wheel 11 based on the electric signal Sa generated by the first rotation angle sensor 33. Then, the reaction force control unit 35 obtains a deviation between the target steering angle θ* and the actual steering angle θs, and controls power supply to the reaction force motor 31 so as to eliminate the deviation.

  Further, the reaction force control unit 35 executes the connection/disconnection control for switching the connection/disconnection of the clutch 21 based on whether or not the clutch connection condition is satisfied. Examples of clutch connection conditions include the following (a) to (c).

  a. The vehicle start switch is turned off. The start switch is a switch that switches between energization and interruption of electric power supplied from the vehicle drive source. A start signal Sig indicating the on/off state of the start switch is input to the reaction force control unit 35 and the steering control unit 47.

b. Abnormalities are detected in the components for generating the steering reaction force including the reaction force motor 31.
c. An abnormality is detected in the configuration for generating the steering force including the steering motor 41.

  The reaction force control unit 35 generates a command signal to connect the clutch 21 when the clutch connection condition is satisfied. On the other hand, the reaction force control unit 35 generates a command signal to disconnect the clutch 21 when the clutch connection condition is not satisfied. The clutch control unit 22 controls the engagement/disengagement of the clutch 21 based on the command signal generated by the reaction force control unit 35.

  Further, the steering device 10 includes a steering motor 41, a second deceleration mechanism 42, a second pinion shaft 43, and a second pinion shaft 43 as a component for generating a steering force that is power for steering the steered wheels 16, 16. It has a two-rotation angle sensor 44, a torque angle sensor (hereinafter referred to as “TAS46”), and a steering control unit 47. The first sensor described in the claims is the second rotation angle sensor 44.

  The second reduction mechanism 42 and the second pinion shaft 43 form a transmission mechanism that transmits the power generated by the steering motor 41 to the steering shaft 14. The first pinion shaft 13, the steered shaft 14, the steered motor 41, the second reduction mechanism 42, the second pinion shaft 43, and the second rotation angle sensor 44 constitute a steered unit U2 as a mechanical device. Further, the steering unit U2, the TAS 46, and the steering control unit 47 form a steering device 10b.

  The steered motor 41 is a source of a steered force. As the steering motor 41, for example, a three-phase (U-phase, V-phase, W-phase) brushless motor is adopted. The rotating shaft of the steered motor 41 is connected to the second pinion shaft 43 via the second reduction mechanism 42. The second reduction gear mechanism 42 reduces the rotation of the steered motor 41 and transmits the reduced rotation force to the steering shaft 12. The second pinion teeth 43 a of the second pinion shaft 43 are meshed with the second rack teeth 14 b of the steered shaft 14. The torque of the steered motor 41 is applied to the steered shaft 14 as a steered force via the second pinion shaft 43. The steered shaft 14 moves in the vehicle width direction (left-right direction in the drawing) according to the rotation of the steered motor 41.

  The second rotation angle sensor 44 is provided in the steering motor 41. The second rotation angle sensor 44 is a relative angle sensor that detects the rotation angle of the rotation shaft of the steering motor 41 in the range of 0 degrees to 360 degrees. The second rotation angle sensor 44 generates an electric signal Sb according to the rotation angle θb of the rotation shaft of the steering motor 41. An MR sensor, for example, is used as the second rotation angle sensor 44. The electric signal Sb is a sine wave signal Ssin that changes sinusoidally with respect to the rotation angle θb of the rotation shaft of the steering motor 41, and a cosine wave signal that changes cosine wave with respect to the rotation angle θb of the rotation shaft of the steering motor 41. It contains the wave signal Scos.

  The TAS 46 is an absolute angle sensor that detects the torque Tp that acts on the first pinion shaft 13 and detects the pinion angle θpa that is the absolute position of the first pinion shaft 13 over multiple rotations of more than 360 degrees. The TAS 46 is provided on the first pinion shaft 13 (specifically, a housing that houses the first pinion shaft 13 together with the steered shaft 14). The TAS 46 includes a first pinion angle sensor 46a and a second pinion angle sensor 46b for detecting the pinion angle θpa of the first pinion shaft 13, and a pinion torque sensor 46c for detecting a torque Tp acting on the first pinion shaft 13. have. On the outer periphery of the first pinion shaft 13, two gear portions having different numbers of teeth are meshed with each other. A gear that meshes with the first gear portion and the second gear portion is provided on the outer peripheral surface of the first pinion shaft 13. The reduction ratio of the first gear portion and the reduction ratio of the second gear portion are different from each other. The first pinion angle sensor 46a is a relative angle sensor that detects the rotation angle of the first gear portion that rotates in response to the rotation of the first pinion shaft 13 in the range of 0 degrees to 360 degrees. The first pinion angle sensor 46a generates an electric signal Sg1 according to the rotation angle of the first gear portion. The electrical signal Sg1 includes a sine wave signal Ssin that changes sinusoidally with respect to the rotation angle of the first gear portion, and a cosine wave signal Scos that changes cosine wave with respect to the rotation angle of the first gear portion. The second pinion angle sensor 46b is a relative angle sensor that detects the rotation angle of the second gear portion that rotates in response to the rotation of the first pinion shaft 13 in the range of 0 degrees to 360 degrees. The second pinion angle sensor 46b generates an electric signal Sg2 according to the rotation angle of the second gear portion. The electric signal Sg2 includes a sine wave signal Ssin that changes sinusoidally with respect to the rotation angle of the second gear portion, and a cosine wave signal Scos that changes cosine wave with respect to the rotation angle of the second gear portion. An MR sensor, for example, is adopted as the first pinion angle sensor 46a and the second pinion angle sensor 46b. The second sensors described in the claims are the first pinion angle sensor 46a and the second pinion angle sensor 46b.

  The steered control unit 47 executes steered control to steer the steered wheels 16 and 16 according to the steering state through control of the steered motor 41. The steering control unit 47 calculates a pinion angle θpa (absolute angle) that is an actual rotation angle of the first pinion shaft 13 based on the rotation angle θb of the steering motor 41 detected by the second rotation angle sensor 44. The steering motor 41 and the second pinion shaft 43 are interlocked with each other via the second reduction gear mechanism 42. Therefore, there is a correlation between the rotation angle θb of the rotation shaft of the steered motor 41 and the rotation angle of the second pinion shaft 43. The second pinion teeth 43 a of the second pinion shaft 43 are meshed with the second rack teeth 14 b of the steered shaft 14, and the first pinion teeth 13 a of the first pinion shaft 13 are the first rack teeth 14 a of the steered shaft 14. Therefore, there is a correlation between the pinion angle θpb which is the rotation angle of the second pinion shaft 43 and the pinion angle θpa of the first pinion shaft 13. Therefore, the pinion angle θpa can be obtained based on the rotation angle θb of the rotation shaft of the steering motor 41. The steering control unit 47 calculates the pinion angle θpa of the first pinion shaft 13 based on the electric signal Sb generated by the second rotation angle sensor 44. Further, the turning control unit 47 calculates the target pinion angle using the target steering angle θ* calculated by the reaction force control unit 35. Then, the steering control unit 47 obtains a deviation between the target pinion angle and the actual pinion angle θpa, and controls power supply to the steering motor 41 so as to eliminate the deviation.

  As the communication standard between the steering control unit 47 and the TAS 46, for example, SPI (Serial Peripheral Interface) is adopted. SPI is a type of synchronous serial communication standard.

  Further, the steered control unit 47 also executes the connection/disconnection control for switching the connection/disconnection of the clutch 21 based on the success or failure of the previous clutch connection conditions (a) to (c). The steering control unit 47 generates a command signal for connecting the clutch 21 when the clutch connection condition is satisfied, and generates a command signal for disconnecting the clutch when the clutch connection condition is not satisfied. This command signal is for the clutch control unit 22. When the command signal cannot be acquired from the reaction force control unit 35, the clutch control unit 22 controls the engagement/disengagement of the clutch 21 based on the command signal generated by the steering control unit 47.

  When the clutch 21 is in the engaged state, the steering control unit 47 controls the operation of the steering motor 41 based on the torque Tp acting on the first pinion shaft 13 detected by the pinion torque sensor 46c of the TAS 46. You can In this case, the steering control unit 47 executes the assist control for assisting the rotation operation of the steering wheel 11 by the driver. An example of such a case where the steering control unit 47 executes the assist control is a case where the reaction force control unit 35 stops operating.

  Further, the steered control unit 47 also executes the connection/disconnection control for switching the connection/disconnection of the clutch 21 based on the success or failure of the previous clutch connection conditions (a) to (c). The steering control unit 47 generates a command signal for connecting the clutch 21 when the clutch connection condition is satisfied, and generates a command signal for disconnecting the clutch when the clutch connection condition is not satisfied. This command signal is for the clutch control unit 22. When the command signal cannot be acquired from the reaction force control unit 35, the clutch control unit 22 controls the engagement/disengagement of the clutch 21 based on the command signal generated by the steering control unit 47.

The function of the steering control unit 47 will be described.
As shown in FIG. 2, the turning control unit 47 as an angle calculation device includes a first calculation circuit 50, a second calculation circuit 60, a third calculation circuit 70, and a drive circuit 80.

  The first arithmetic circuit 50 is configured by packaging a logic circuit, which is a combination of electronic circuits and flip-flops, in a single chip. The first arithmetic circuit 50 is a so-called ASIC (application specific integrated circuit). The first arithmetic circuit 50 performs a predetermined output with respect to a specific input (here, the electric signal Sb of the second rotation angle sensor 44). The first arithmetic circuit 50 is always connected to the battery 90 mounted on the vehicle via the first connection line 91, and connected to the battery 90 via the second connection line 93 provided with the power supply relay 92 in the middle. Has been done. As the power supply relay 92, a mechanical relay, FET (field effect transistor), or the like is adopted. The power supply relay 92 opens and closes according to the start signal Sig. That is, when the start switch is turned on, in other words, when the start signal Sig indicating the on state is input to the power supply relay 92, power is supplied between the battery 90 and the first arithmetic circuit 50 through the power supply relay 92. It is energized. When the start switch is turned off, in other words, when the start signal Sig indicating the off state is input to the power supply relay 92, power is cut off between the battery 90 and the first arithmetic circuit 50 through the power supply relay 92. It Further, the electric signal Sb generated by the second rotation angle sensor 44 is input to the first arithmetic circuit 50. Based on the electric signal Sb, the first arithmetic circuit 50 outputs to the third arithmetic circuit 70 a count value C as rotational speed information indicating the multi-turn number (multi-rotation number) of the steering motor 41, as described later. ..

  The first arithmetic circuit 50 includes a power supply circuit 100 that lowers the power supply voltage of the battery 90 to a control voltage Vco within a predetermined voltage range. A first connection line 91 and a second connection line 93 are connected to the power supply circuit 100. The third arithmetic circuit 70 and the second arithmetic circuit 60 are connected to the power supply circuit 100 via a connection line 100a. The power supply circuit 100 applies the control voltage Vco to the third arithmetic circuit 70 and the second arithmetic circuit 60.

  The drive circuit 80 is connected to the battery 90 via a power supply line 94 in which a drive relay 95 is provided. As the drive relay 95, a mechanical relay, an FET (field effect transistor), or the like is used.

  The third arithmetic circuit 70 is connected to the battery 90 via the first arithmetic circuit 50. The third arithmetic circuit 70 operates by being supplied with the control voltage Vco within the predetermined voltage range from the first arithmetic circuit 50 when the start switch is in the ON state. The third arithmetic circuit 70 outputs a relay signal Srl to the drive relay 95 when the third arithmetic circuit 70 starts its operation by being supplied with the control voltage Vco from the first arithmetic circuit 50. The drive relay 95 opens and closes according to the relay signal Srl output from the third arithmetic circuit 70. When the drive relay 95 is closed based on the relay signal Srl, drive power can be supplied to the steered motor 41.

  The second arithmetic circuit 60 is configured by packaging a logic circuit, which is a combination of electronic circuits and flip-flops, in a single chip. The second arithmetic circuit 60 is a so-called ASIC. The second arithmetic circuit 60 performs a predetermined output with respect to a specific input (here, the electric signal Sg1 of the first pinion angle sensor 46a and the electric signal Sg2 of the second pinion angle sensor 46b). The second arithmetic circuit 60 operates by being supplied with the control voltage Vco within a predetermined voltage range from the first arithmetic circuit 50 when the start switch is in the ON state. Further, the electric signal Sg1 generated by the first pinion angle sensor 46a and the electric signal Sg2 generated by the second pinion angle sensor 46b are input to the second arithmetic circuit 60. The second arithmetic circuit 60, based on the electric signals Sg1 and Sg2, first absolute angle information θg1 and second absolute angle information θg1 which are absolute angle information for calculating the pinion angle θpa of the first pinion shaft 13 as described later. The absolute angle information θg2 is calculated, and the first absolute angle information θg1 and the second absolute angle information θg2 are output to the third arithmetic circuit 70.

  When the control voltage Vco is supplied, the third arithmetic circuit 70 calculates the pinion angle θpa of the first pinion shaft 13 and controls the electric power supplied to the steered motor 41. The third arithmetic circuit 70 includes, for example, a micro processing unit (microcomputer). The first arithmetic circuit 50 and the second arithmetic circuit 60 are connected to the third arithmetic circuit 70. The count value C calculated by the first calculation circuit 50 and the first absolute angle information θg1 and the second absolute angle information θg2 calculated by the second calculation circuit 60 are input to the third calculation circuit 70. Further, the third calculation circuit 70 has an electric signal Sb generated by the second rotation angle sensor 44, a vehicle speed V detected by the vehicle speed sensor 36, and a target steering angle θ* calculated by the reaction force control unit 35. Then, the actual current value I detected by the current sensor 81 and the torque Tp detected by the pinion torque sensor 46c are input. The current sensor 81 is provided in the power feeding path between the steering motor 41 and the drive circuit 80. The third arithmetic circuit 70 calculates a motor control signal Sm necessary for driving the steered motor 41 based on these various input values. The third arithmetic circuit 70 outputs the calculated motor control signal Sm to the drive circuit 80.

The function of the first arithmetic circuit 50 will be described.
As shown in FIG. 3, the first arithmetic circuit 50 includes a power supply circuit 100, a counter circuit 101, and a communication interface 102.

  As shown in FIGS. 2 and 3, the power supply circuit 100 is connected to the third arithmetic circuit 70 and the second arithmetic circuit 60 via a connection line 100a, and each circuit constituting the first arithmetic circuit 50. Are connected. Note that, in FIG. 3, for convenience, a connecting line that connects the power supply circuit 100 and each circuit forming the first arithmetic circuit 50 is omitted. The power supply circuit 100 supplies the control voltage Vco to the third arithmetic circuit 70 and the second arithmetic circuit 60 only when the starting switch is in the ON state, while the first arithmetic operation is performed regardless of the ON state and the OFF state of the starting switch. The control voltage Vco is constantly supplied to each circuit constituting the circuit 50. As a result, each circuit forming the first arithmetic circuit 50 operates not only when the start switch is in the on state but also when it is in the off state. Further, the power supply circuit 100 constantly supplies the operating voltage necessary for the operation of the second rotation angle sensor 44 to the second rotation angle sensor 44 regardless of the ON state and the OFF state of the start switch.

  As shown in FIG. 3, the electric signal Sb generated by the second rotation angle sensor 44 is input to the counter circuit 101. The counter circuit 101 calculates the count value C used for calculating the rotation angle of the multi-turn of the steering motor 41 based on the electric signal Sb. The count value C is rotation speed information indicating the number of multi-turns of the steering motor 41. In the present embodiment, the count value C is information indicating how many rotations the rotation position of the rotation shaft of the steered motor 41 rotates with respect to the reference position.

  The counter circuit 101 includes a counter unit 101a, a counter abnormality detection unit 108, and a counter BIST unit 110. The counter unit 101a includes an amplifier 103, a comparator 104, a quadrant determination unit 105, and a count value calculation unit 106.

  The electric signal Sb generated by the second rotation angle sensor 44 is input to the amplifier 103. The amplifier 103 amplifies the electric signal Sb input from the second rotation angle sensor 44 and outputs it to the comparator 104.

  The comparator 104 generates a Hi level signal when the electric signal Sb amplified by the amplifier 103 has a value equal to or larger than the set threshold value, and a Lo level signal when the electric signal Sb has a value smaller than the threshold value. This threshold is set to "0", for example.

  The quadrant determination unit 105 generates quadrant information, which is information indicating a quadrant in which the rotational position of the rotating shaft of the steered motor 41 exists, based on the Hi-level signal and the Lo-level signal generated by the comparator 104. .. One rotation (360 degrees) of the rotating shaft of the steered motor 41 is divided into four quadrants every 90 degrees based on the positive/negative combination of the electric signal Sb. The quadrant determination unit 105 generates the left rotation flag Fl or the right rotation flag Fr based on the change in the quadrant in which the rotation position of the rotation shaft of the steered motor 41 indicated by the quadrant information exists. It is assumed that the quadrant determination unit 105 rotates the unit rotation amount (90 degrees) every time the quadrant in which the rotational position of the rotation shaft of the steered motor 41 exists changes to the adjacent quadrant. The quadrant determination unit 105 determines that the rotational position of the rotary shaft of the steered motor 41 is based on the relationship between the quadrant existing before the rotation of the steered motor 41 and the quadrant existing after the rotation of the steered motor 41. The rotation direction of the rotary shaft of the rudder motor 41 is specified.

  The count value calculation unit 106 calculates the count value C based on the left rotation flag Fl or the right rotation flag Fr acquired from the quadrant determination unit 105. The count value calculation unit 106 is a logic circuit that combines flip-flops and the like. The count value C indicates the number of times the rotational position of the rotary shaft of the steered motor 41 has rotated by a unit rotational amount (90 degrees) with respect to its reference position. The count value calculation unit 106 increments (adds 1 to the count value C) each time the left rotation flag Fl is acquired from the quadrant determination unit 105, and decrements (counts the count value every time the right rotation flag Fr is acquired from the quadrant determination unit 105. Subtract 1 from C). As described above, the count value calculation unit 106 is configured to calculate the count value C each time the second rotation angle sensor 44 generates the electric signal Sb and store the count value C. .. The count value C calculated by the count value calculation unit 106 is output to the communication interface 102.

  The communication interface 102 is configured to operate when the start switch is in the on state, and not operate when the start switch is in the off state. When the count value C is input, the communication interface 102 outputs the count value C to the third arithmetic circuit 70.

  Further, the first arithmetic circuit 50 is provided with a voltage abnormality detector 107 for detecting an abnormality of the power supply circuit 100 and a counter abnormality detector 108 for detecting an abnormality of the count value calculator 106. The voltage abnormality detection unit 107 is provided as a function separate from the function of the counter circuit 101, and the counter abnormality detection unit 108 is provided as one of the functions of the counter circuit 101. The first abnormality detection unit described in the claims is the voltage abnormality detection unit 107 and the counter abnormality detection unit 108.

  The voltage abnormality detection unit 107 detects an abnormality of the power supply circuit 100 based on whether the control voltage Vco output from the power supply circuit 100 is within a predetermined voltage range. Specifically, the voltage abnormality detection unit 107 detects the control voltage Vco output from the power supply circuit 100, determines whether the control voltage Vco is higher than the upper limit value of the predetermined voltage range, and the lower limit of the predetermined voltage range. Whether or not there is an abnormality in the power supply circuit 100 is detected based on whether the value is smaller than the value. When the control voltage Vco is higher than the upper limit value of the predetermined voltage range or smaller than the lower limit value of the predetermined voltage range, the voltage abnormality detection unit 107 indicates a voltage abnormality flag indicating a detection result indicating that the power supply circuit 100 is abnormal. Generate Fb. On the other hand, the voltage abnormality detection unit 107 does not generate the voltage abnormality flag Fb when the control voltage Vco is equal to or lower than the upper limit value of the predetermined voltage range and equal to or higher than the lower limit value of the predetermined voltage range. The voltage abnormality flag Fb generated by the voltage abnormality detection unit 107 is output to the communication interface 102.

  The counter abnormality detection unit 108 is configured to hold the count value C, which is the output value of the count value calculation unit 106, for two consecutive calculation cycles. That is, the counter abnormality detection unit 108 uses the count current value Cn that is the count value C of the latest (current) calculation cycle and the count previous value Cn−1 that is the count value C of the immediately previous (previous) calculation cycle. Hold. Then, the counter abnormality detection unit 108 detects an abnormality in the count value calculation unit 106 based on the left rotation flag Fl or the right rotation flag Fr, the count current value Cn, and the count previous value Cn−1 acquired by the quadrant determination unit 105. To judge. Specifically, the counter abnormality detection unit 108 determines that the difference between the current count value Cn and the previous count value Cn-1 is indicated by the left rotation flag Fl or the right rotation flag Fr acquired by the quadrant determination unit 105. If the rotation direction of the motor 41 is not matched, the count value calculation unit 106 generates a counter abnormality flag Fc indicating the detection result of abnormality. For example, the counter abnormality detection unit 108 generates the counter abnormality flag Fc if the difference between the count current value Cn and the count previous value Cn−1 is not within the predetermined range when the steering motor 41 is not rotating. .. On the other hand, the counter abnormality detection unit 108 does not generate the counter abnormality flag Fc if the difference between the count current value Cn and the count previous value Cn-1 is within the predetermined range when the steering motor 41 is not rotating. .. Further, the counter abnormality detection unit 108, when the steering motor 41 is rotating, indicates the difference between the count current value Cn and the count previous value Cn-1 in the left rotation flag Fl or the right rotation flag Fr. If it matches the rotation direction of the motor 41, the counter abnormality flag Fc is not generated. On the other hand, when the steering motor 41 is rotating, the counter abnormality detection unit 108 indicates that the difference between the count current value Cn and the count previous value Cn-1 is indicated by the left rotation flag Fl or the right rotation flag Fr. When the rotation direction of the motor 41 is not matched, the counter abnormality flag Fc is generated. The counter abnormality flag Fc generated by the counter abnormality detection unit 108 is output to the communication interface 102.

  Here, when an abnormality occurs in the voltage abnormality detection unit 107, it becomes impossible to detect the abnormality detection target of the voltage abnormality detection unit 107, that is, the abnormality of the power supply circuit 100. When an abnormality occurs in the counter abnormality detection unit 108, the abnormality detection target of the counter abnormality detection unit 108, that is, the abnormality of the count value calculation unit 106 cannot be detected.

  Therefore, the first arithmetic circuit 50 of the present embodiment is provided with a BIST (Built-in Self-test) unit that diagnoses the voltage abnormality detection unit 107 and the counter abnormality detection unit 108. Specifically, the power supply BIST unit 109 that diagnoses the voltage abnormality detection unit 107 is provided as a function separate from the function of the counter circuit 101, and the counter BIST unit 110 that diagnoses the counter abnormality detection unit 108 includes the counter circuit 101. It is provided as one of the functions. The first BIST unit described in the claims is the counter BIST unit 110.

  When diagnosing the voltage abnormality detection unit 107, the power supply BIST unit 109 changes the upper limit value of the predetermined voltage range assumed for the voltage abnormality detection unit 107 to detect the abnormality of the control voltage Vco, and detects the voltage abnormality. The unit 107 operates to forcibly create a situation in which the voltage abnormality flag Fb is generated. Then, the power supply BIST unit 109 diagnoses the voltage abnormality detection unit 107 based on whether the voltage abnormality detection unit 107 has generated the voltage abnormality flag Fb. In this diagnosis, the power supply BIST unit 109 generates a power supply BIST abnormality flag F1 indicating a diagnosis result that the voltage abnormality detection unit 107 is abnormal when the voltage abnormality detection unit 107 does not generate the voltage abnormality flag Fb. On the other hand, the power supply BIST unit 109 does not generate the power supply BIST abnormality flag F1 when the voltage abnormality detection unit 107 generates the voltage abnormality flag Fb. The power BIST abnormality flag F1 generated by the power BIST unit 109 is output to the communication interface 102.

  When diagnosing the counter abnormality detection unit 108, the counter BIST unit 110 outputs a test signal indicating a left rotation flag Fl, a right rotation flag Fr, and a count value C that are defined so as to derive the abnormality detection result, to the counter abnormality. It outputs to the detection unit 108, and operates to forcibly create a situation in which the counter abnormality detection unit 108 generates the counter abnormality flag Fc. Then, the counter BIST unit 110 diagnoses the counter abnormality detection unit 108 based on whether the counter abnormality detection unit 108 has generated the counter abnormality flag Fc. In this diagnosis, the counter BIST unit 110 generates a counter BIST abnormality flag F1a indicating a diagnosis result that the counter abnormality detection unit 108 is abnormal when the counter abnormality detection unit 108 does not generate the counter abnormality flag Fc. On the other hand, the counter BIST unit 110 does not generate the counter BIST abnormality flag F1a when the counter abnormality detection unit 108 generates the counter abnormality flag Fc. The counter BIST abnormality flag F1a generated by the counter BIST unit 110 is output to the communication interface 102.

  When the voltage abnormality flag Fb, the counter abnormality flag Fc, the power supply BIST abnormality flag F1 and the counter BIST abnormality flag F1a are input, the communication interface 102 outputs these flags to the third arithmetic circuit 70.

The function of the second arithmetic circuit 60 will be described.
As shown in FIG. 4, the second arithmetic circuit 60 calculates the first absolute angle information θg1 and outputs the first absolute angle information arithmetic circuit 120, and the second absolute angle information θg2 calculates and outputs the second absolute angle information θg2. An absolute angle information calculation circuit 130 is provided.

  The first absolute angle information calculation circuit 120 is provided with a first absolute angle information calculation unit 121, a first absolute angle information abnormality detection unit 122, a first absolute angle information BIST unit 123, and a communication interface 124. The first absolute angle information calculation unit 121 includes an amplifier 125 and an A/D converter 126 (analog/digital converter).

  The electric signal Sg1 generated by the first pinion angle sensor 46a is input to the amplifier 125. The amplifier 125 amplifies the electric signal Sg1 input from the first pinion angle sensor 46a and outputs it to the A/D converter 126.

The A/D converter 126 converts the electric signal Sg1 (analog signal) amplified by the amplifier 125 into a digital signal and outputs it as the first absolute angle information θg1.
The communication interface 124 is configured to operate when the start switch is in the on state, and not operate when the start switch is in the off state. When the first absolute angle information θg1 is input, the communication interface 124 outputs the first absolute angle information θg1 to the third arithmetic circuit 70.

  The second absolute angle information calculation circuit 130 is provided with a second absolute angle information calculation unit 131, a second absolute angle information abnormality detection unit 132, a second absolute angle information BIST unit 133, and a communication interface 134. The second absolute angle information calculation unit 131 includes an amplifier 135 and an A/D converter 136. The absolute position information calculation unit described in the claims is the first absolute angle information calculation unit 121 and the second absolute angle information calculation unit 131.

  The electric signal Sg2 generated by the second pinion angle sensor 46b is input to the amplifier 135. The amplifier 135 amplifies the electric signal Sg2 input from the second pinion angle sensor 46b and outputs it to the A/D converter 136.

The A/D converter 136 converts the electric signal Sg2 (analog signal) amplified by the amplifier 135 into a digital signal, and outputs it as second absolute angle information θg2.
The communication interface 134 is configured to operate when the start switch is on and not operate when the start switch is off. When the second absolute angle information θg2 is input, the communication interface 134 outputs the second absolute angle information θg2 to the third arithmetic circuit 70.

  The second arithmetic circuit 60 includes a first absolute angle information abnormality detecting unit 122 for detecting an abnormality of the first absolute angle information arithmetic unit 121 and a second absolute angle information abnormality for detecting an abnormality of the second absolute angle information arithmetic unit 131. A detection unit 132 is provided. The first absolute angle information abnormality detection unit 122 is provided as a function separate from the function of the first absolute angle information calculation unit 121. Further, the second absolute angle information abnormality detection unit 132 is provided as a function separate from the function of the second absolute angle information calculation unit 131. The second abnormality detection unit described in the claims is the first absolute angle information abnormality detection unit 122 and the second absolute angle information abnormality detection unit 132.

  The first absolute angle information abnormality detection unit 122 is configured to be able to hold the first absolute angle information θg1 which is the output value from the A/D converter 126 for two consecutive calculation cycles. That is, the first absolute angle information abnormality detection unit 122 holds the first absolute angle information θg1 of the latest (current) operation cycle and the first absolute angle information θg1 of the immediately previous (previous) operation cycle. Further, the first absolute angle information abnormality detection unit 122, based on the first absolute angle information θg1 of the previous calculation cycle, the first absolute angle information θg1 of the current calculation cycle, and the electric signal Sg1, the first absolute angle information. The abnormality of the arithmetic unit 121 is determined. Specifically, the first absolute angle information abnormality detection unit 122 obtains the difference between the first absolute angle information θg1 of the previous calculation cycle and the first absolute angle information θg1 of the current calculation cycle from the electric signal Sg1. When the rotation direction of the steered motor 41 is not matched, the first absolute angle information abnormality flag Faa indicating the detection result of abnormality is generated in the first absolute angle information calculation unit 121. For example, when the steered motor 41 is not rotating, the first absolute angle information abnormality detection unit 122 calculates the first absolute angle information θg1 of the previous calculation cycle and the first absolute angle information θg1 of the current calculation cycle. If the difference is not within the predetermined range, the first absolute angle information abnormality flag Faa is generated. On the other hand, when the steered motor 41 is not rotating, the first absolute angle information abnormality detection unit 122 calculates the first absolute angle information θg1 of the previous calculation cycle and the first absolute angle information θg1 of the current calculation cycle. If the difference is within the predetermined range, the first absolute angle information abnormality flag Faa is not generated. In addition, the first absolute angle information abnormality detection unit 122, when the steered motor 41 is rotating, combines the first absolute angle information θg1 of the previous calculation cycle and the first absolute angle information θg1 of the current calculation cycle. If the difference corresponds to the rotation direction of the steered motor 41 obtained from the electric signal Sg1, the first absolute angle information abnormality flag Faa is not generated. On the other hand, when the steered motor 41 is rotating, the first absolute angle information abnormality detection unit 122 detects the first absolute angle information θg1 of the previous calculation cycle and the first absolute angle information θg1 of the current calculation cycle. When the difference does not match the rotation direction of the steered motor 41 obtained from the electric signal Sg1, the first absolute angle information abnormality flag Faa is generated. The first absolute angle information abnormality flag Faa generated by the first absolute angle information abnormality detection unit 122 is output to the communication interface 124.

  The second absolute angle information abnormality detection unit 132 is configured to be able to hold the second absolute angle information θg2, which is the output value from the A/D converter 136, for two consecutive calculation cycles. That is, the second absolute angle information abnormality detection unit 132 holds the second absolute angle information θg2 of the latest (current) calculation cycle and the second absolute angle information θg2 of the immediately previous (previous) calculation cycle. Further, the second absolute angle information abnormality detection unit 132, based on the second absolute angle information θg2 of the previous calculation cycle, the second absolute angle information θg2 of the current calculation cycle, and the electric signal Sg2, the second absolute angle information. The abnormality of the arithmetic unit 131 is determined. Specifically, the second absolute angle information abnormality detection unit 132 obtains the difference between the second absolute angle information θg2 of the previous calculation cycle and the second absolute angle information θg2 of the current calculation cycle from the electric signal Sg2. When the rotation direction of the steered motor 41 is not matched, the second absolute angle information calculation unit 131 generates a second absolute angle information abnormality flag Fab that indicates the detection result of abnormality. For example, when the steered motor 41 is not rotating, the second absolute angle information abnormality detection unit 132 sets the second absolute angle information θg2 of the previous calculation cycle and the second absolute angle information θg2 of the current calculation cycle. If the difference is not within the predetermined range, the second absolute angle information abnormality flag Fab is generated. On the other hand, when the steered motor 41 is not rotating, the second absolute angle information abnormality detection unit 132 compares the second absolute angle information θg2 of the previous calculation cycle and the second absolute angle information θg2 of the current calculation cycle. If the difference is within the predetermined range, the second absolute angle information abnormality flag Fab is not generated. Further, the second absolute angle information abnormality detection unit 132, when the steered motor 41 is rotating, combines the second absolute angle information θg2 of the previous calculation cycle and the second absolute angle information θg2 of the current calculation cycle. If the difference corresponds to the rotation direction of the steered motor 41 obtained from the electric signal Sg2, the second absolute angle information abnormality flag Fab is not generated. On the other hand, when the steered motor 41 is rotating, the second absolute angle information abnormality detection unit 132 detects the second absolute angle information θg2 of the previous calculation cycle and the second absolute angle information θg2 of the current calculation cycle. When the difference does not match the rotation direction of the steering motor 41 obtained from the electric signal Sg2, the second absolute angle information abnormality flag Fab is generated. The second absolute angle information abnormality flag Fab generated by the second absolute angle information abnormality detection unit 132 is output to the communication interface 134.

  Here, if an abnormality occurs in the first absolute angle information abnormality detection unit 122, the abnormality detection target of the first absolute angle information abnormality detection unit 122, that is, the abnormality of the first absolute angle information calculation unit 121 can be detected. Disappear. Further, when an abnormality occurs in the second absolute angle information abnormality detection unit 132, the abnormality detection target of the second absolute angle information abnormality detection unit 132, that is, the abnormality of the second absolute angle information calculation unit 131 cannot be detected. ..

  Therefore, in the second arithmetic circuit 60 of the present embodiment, the first absolute angle information BIST unit 123 that diagnoses the first absolute angle information abnormality detection unit 122 has a function different from the function of the first absolute angle information arithmetic unit 121. The second absolute angle information BIST unit 133 for diagnosing the second absolute angle information abnormality detection unit 132 is provided as a function separate from the function of the second absolute angle information calculation unit 131. The second BIST unit described in the claims is the first absolute angle information BIST unit 123 and the second absolute angle information BIST unit 133.

  When diagnosing the first absolute angle information abnormality detection unit 122, the first absolute angle information BIST unit 123 determines the rotation direction of the steered motor 41 and the first absolute angle information θg1 that are defined so as to derive the abnormality detection result. Is output to the first absolute angle information abnormality detection unit 122, and the first absolute angle information abnormality detection unit 122 forcibly creates a situation in which the first absolute angle information abnormality flag Faa is generated. Operate. Then, the first absolute angle information BIST unit 123 detects the first absolute angle information abnormality detection unit 122 based on whether the first absolute angle information abnormality detection unit 122 has generated the first absolute angle information abnormality flag Faa. Diagnose. In this diagnosis, the first absolute angle information BIST unit 123 determines that the first absolute angle information abnormality detection unit 122 is abnormal when the first absolute angle information abnormality detection unit 122 does not generate the first absolute angle information abnormality flag Faa. The first absolute angle information BIST abnormality flag F2a indicating a certain diagnosis result is generated. On the other hand, when the first absolute angle information abnormality detection unit 122 generates the first absolute angle information abnormality flag Faa, the first absolute angle information BIST section 123 does not generate the first absolute angle information BIST abnormality flag F2a. The first absolute angle information BIST abnormality flag F2a generated by the first absolute angle information BIST unit 123 is output to the communication interface 124.

  When the first absolute angle information abnormality flag Faa and the first absolute angle information BIST abnormality flag F2a are input, the communication interface 124 outputs these flags to the third arithmetic circuit 70.

  The second absolute angle information BIST unit 133, when diagnosing the second absolute angle information abnormality detection unit 132, determines the rotation direction of the steered motor 41 and the second absolute angle information θg2 that are defined so as to derive the abnormality detection result. Is output to the second absolute angle information abnormality detection unit 132 so that the second absolute angle information abnormality detection unit 132 forcibly creates a situation in which the second absolute angle information abnormality flag Fab is generated. Operate. Then, the second absolute angle information abnormality detection unit 132 detects the second absolute angle information abnormality detection unit 132 based on whether the second absolute angle information abnormality detection unit 132 has generated the second absolute angle information abnormality flag Fab. Diagnose. In this diagnosis, the second absolute angle information BIST unit 133 determines that the second absolute angle information abnormality detection unit 132 is abnormal when the second absolute angle information abnormality detection unit 132 does not generate the second absolute angle information abnormality flag Fab. A second absolute angle information BIST abnormality flag F2b indicating a certain diagnosis result is generated. On the other hand, the second absolute angle information BIST abnormality unit 133 does not generate the second absolute angle information BIST abnormality flag F2b when the second absolute angle information abnormality detection unit 132 generates the second absolute angle information abnormality flag Fab. The second absolute angle information BIST abnormality flag F2b generated by the second absolute angle information BIST unit 133 is output to the communication interface 134.

  When the first absolute angle information abnormality flag Faa and the first absolute angle information BIST abnormality flag F2a are input, the communication interface 124 outputs these flags to the third arithmetic circuit 70.

The function of the third arithmetic circuit 70 will be described.
As shown in FIG. 5, the third calculation circuit 70 includes an integrated angle calculation unit 140, an absolute angle calculation unit 141, an absolute angle output unit 143, a steering angle command value calculation unit 144, a current feedback control unit 145, and a third abnormality. An absolute angle abnormality detection unit 146 as a detection unit, an absolute angle BIST unit 147 as a third BIST unit, and a BIST control unit 148 are provided.

  The integrated angle calculation unit 140 acquires the count value C calculated by the first calculation circuit 50 and the electric signal Sb generated by the second rotation angle sensor 44. In the present embodiment, the integrated angle calculation unit 140 acquires the count value C calculated by the first calculation circuit 50 every time the start switch is turned on. The integrated angle calculation unit 140 uses the count value C acquired when the start switch is in the ON state while the start switch is in the ON state as a change in the quadrant of the electric signal Sb generated by the second rotation angle sensor 44. It is updated based on a predetermined calculation cycle. The integrated angle calculation unit 140 increments the count value C (adds 1 to the count value C) and updates it each time the quadrant of the electric signal Sb changes to a quadrant adjacent in the counterclockwise direction. The integrated angle calculation unit 140 decrements (count value C is decremented by 1) and updates the count value C each time the quadrant of the electric signal Sb changes to the adjacent quadrant in the clockwise direction. That is, in the present embodiment, the third arithmetic circuit 70 updates the count value C separately from the first arithmetic circuit 50 while the start switch is in the ON state.

  Further, the integrated angle calculation unit 140 of the third calculation circuit 70 acquires the electric signal Sb generated by the second rotation angle sensor 44 at a predetermined calculation cycle. The integrated angle calculation unit 140 calculates the integrated angle θi as an absolute angle from a value obtained by integrating the rotation angles of the multi-turns of the steered motor 41 based on the acquired count value C and the electric signal Sb. The integrated angle θi is a value obtained by integrating the rotation angle of the steering motor 41 with a relative angle. Specifically, the integrated angle calculation unit 140 obtains the arc tangent from the electric signal Sb generated by the second rotation angle sensor 44 to obtain the rotation angle of the steering motor 41 as a relative angle. The obtained relative angle represents the rotation angle of the steering motor 41 within the range of 0 degrees to 360 degrees. Then, the integrated angle calculation unit 140 adds the value obtained by multiplying the multi-turn number of the rotation shaft of the steering motor 41 based on the count value C by 360 degrees to the calculated relative angle, thereby turning the steering motor. The integrated angle θi is obtained as a value obtained by integrating the rotation angle of 41. In addition, in consideration of the reduction ratio of the member interposed between the steering motor 41 and the first pinion shaft 13, the value of the first pinion shaft 13 of the first pinion shaft 13 is calculated from the value obtained by integrating the rotation angles of the multi-turns of the steering motor 41. You can find the absolute angle.

  The absolute angle calculation unit 141 calculates the first absolute angle information θg1 calculated by the first absolute angle information calculation circuit 120 of the second calculation circuit 60 and the second absolute angle information calculation circuit 130 of the second calculation circuit 60. The second absolute angle information θg2 is acquired. The absolute angle calculation unit 141 calculates the absolute angle θga of the first pinion shaft 13 based on the first absolute angle information θg1 and the second absolute angle information θg2. Specifically, the absolute angle calculation unit 141 uses the value obtained by obtaining the arc tangent from the first absolute angle information θg1 and the value obtained by obtaining the arc tangent from the second absolute angle information θg2, using the absolute angle of the first pinion shaft 13. Calculate θga. The calculation of the absolute angle θga by the absolute angle calculation unit 141 will be described with reference to FIG.

  The vertical axis of the graph shown in FIG. 6 represents the first absolute angle information θg1 and the second absolute angle information θg2, and the horizontal axis represents the absolute angle θga of the first pinion shaft 13. The broken line shows the transition of the first absolute angle information θg1, and the solid line shows the transition of the second absolute angle information θg2. The electric signal Sg1 of the first pinion angle sensor 46a and the electric signal Sg2 of the second pinion angle sensor 46b have the same axis multiplication angle (1 time). Then, due to the difference between the speed reduction ratio of the first gear portion of the TAS 46 and the speed reduction ratio of the second gear portion of the TAS 46, the phase of the waveform of the first absolute angle information θg1 indicated by the broken line and the second absolute angle information θg2 indicated by the solid line. The phase of the waveform shifts as the first pinion shaft 13 rotates. The first absolute angle information θg1 and the second absolute angle information θg2 are rotation angles (0 degrees to 360 degrees) in the detection ranges of the first pinion angle sensor 46a and the second pinion angle sensor 46b, respectively. Therefore, the absolute angle θga that is the rotation angle of the multi-turn of the first pinion shaft 13 cannot be obtained only by the first absolute angle information θg1 or only the second absolute angle information θg2.

  The absolute angle calculation unit 141 calculates the absolute value of the angle difference between the first absolute angle information θg1 and the second absolute angle information θg2. The thick line in the graph of FIG. 6 indicates the absolute value of the angular difference between the first absolute angle information θg1 and the second absolute angle information θg2. As shown in FIG. 6, as the absolute angle θga increases, the absolute value of the angle difference increases in proportion to the absolute angle θga. The absolute angle calculation unit 141 stores a map showing the relationship between the absolute angle θga and the absolute value of the angular difference between the first absolute angle information θg1 and the second absolute angle information θg2. Therefore, the absolute angle calculation unit 141 can calculate the absolute angle θga from the absolute value of the angle difference between the first absolute angle information θg1 and the second absolute angle information θg2.

  As shown in FIG. 5, the absolute angle output unit 143 is generated by the integrated angle θi calculated by the integrated angle calculation unit 140, the absolute angle θga calculated by the absolute angle calculation unit 141, and the absolute angle abnormality detection unit 146. The absolute angle abnormality detection flag Fa is acquired. The absolute angle output unit 143 calculates the motor midpoint of the steered motor 41 from the absolute angle θga. The motor midpoint refers to the rotation angle θb of the steering motor 41 corresponding to the steering neutral position of the steering wheel 11 or the steering neutral position of the steering shaft 14 in the straight traveling state of the vehicle. When the absolute angle abnormality detection flag Fa is not input, the absolute angle output unit 143 calculates the pinion angle θpa of the first pinion shaft 13 by the absolute angle based on the motor midpoint of the steered motor 41 and the integrated angle θi. .. That is, the absolute angle output unit 143 sets the rotation angle θb of the steering motor 41 to 360 based on the amount of change in the integrated angle θi of the steering motor 41 from the reference point with the motor midpoint of the steering motor 41 as the reference point. The absolute angle in the range exceeding the degree is calculated, and the pinion angle θpa is calculated as the absolute angle based on the calculated rotation angle θb (absolute angle). Since there is a correlation between the rotation angle θb of the steering motor 41 and the rotation angle of the first pinion shaft 13, the absolute angle output unit 143 determines that the absolute angle output unit 143 is based on the rotation angle θb (absolute angle) of the steering motor 41. The pinion angle θpa of the two-pinion shaft 43 can be obtained as an absolute angle. The absolute angle output unit 143 outputs this pinion angle θpa when the absolute angle abnormality detection flag Fa is not input. On the other hand, when the absolute angle abnormality detection flag Fa is input, the absolute angle output unit 143 outputs the absolute angle θga as the pinion angle θpa.

  The steering angle command value calculation unit 144 acquires the pinion angle θpa from the absolute angle output unit 143, the target steering angle θ* calculated by the reaction force control unit 35, and the vehicle speed V detected by the vehicle speed sensor 36. The steering angle command value calculation unit 144 sets a steering angle ratio that is a ratio of the steering angle θt to the steering angle θs according to the traveling state of the vehicle (specifically, the vehicle speed V). The turning angle command value calculation unit 144 calculates a correction angle with respect to the target steering angle θ* calculated by the reaction force control unit 35 in order to realize the set steering angle ratio, and the calculated correction angle is set as a target. A target angle according to the steering angle ratio is calculated by adding it to the steering angle θ*. The steering angle command value calculation unit 144 converts this target angle into a target pinion angle that is a value corresponding to the rotation angle of the first pinion shaft 13. The steering angle command value calculation unit 144 performs angle feedback control (for example, PID control) so that the pinion angle θpa of the first pinion shaft 13 follows the target pinion angle calculated based on the target steering angle θ*. Thus, the current command value I* is calculated.

  The current feedback control unit 145 acquires the actual current value I actually supplied to the steering motor 41 through the current sensor 81 provided in the power feeding path to the steering motor 41. Further, the current feedback control unit 145 acquires the electric signal Sb through the second rotation angle sensor 44. The current feedback control unit 145 generates a motor control signal Sm by executing current feedback control based on the electric signal Sb and the actual current value I so that the actual current value I follows the current command value I*. , PWM signals are output to the drive circuit 80.

  The drive circuit 80 is a three-phase (U phase, V phase, W phase) drive circuit. The drive circuit 80 converts DC power supplied from a battery (not shown) into three-phase AC power by turning on and off the switching elements that form the drive circuit 80 based on the motor control signal Sm. The drive circuit 80 supplies the three-phase AC power to the steering motor 41.

  The absolute angle abnormality detection unit 146 acquires the integrated angle θi calculated by the integrated angle calculation unit 140 and the absolute angle θga calculated by the absolute angle calculation unit 141. The absolute angle abnormality detection unit 146 detects an abnormality in the first arithmetic circuit 50 based on the comparison between the integrated angle θi and the absolute angle θga. Specifically, the absolute angle abnormality detection unit 146 holds the integrated angle θi that is the output value of the integrated angle calculation unit 140 and the absolute angle θga that is the output value of the absolute angle calculation unit 141 for two consecutive calculation cycles. Is configured to be able to. That is, the absolute angle abnormality detection unit 146 holds the integrated angle θi and the absolute angle θga of the latest (current) operation cycle, and the integrated angle θi and the absolute angle θga of the immediately previous (previous) operation cycle. The absolute angle abnormality detection unit 146 calculates the variation amount of the integrated angle θi per unit time (one calculation cycle) based on the deviation between the integrated angle θi of the current calculation cycle and the integrated angle θi of the previous calculation cycle. To do. Further, the absolute angle abnormality detection unit 146 determines the amount of change in the absolute angle θga per unit time (one calculation cycle) based on the deviation between the absolute angle θga of the current calculation cycle and the absolute angle θga of the previous calculation cycle. Is calculated. The absolute angle abnormality detection unit 146 determines that the deviation between the change amount of the integrated angle θi (specifically, a value obtained by converting the change amount of the rotation angle of the first pinion shaft 13) and the change amount of the absolute angle θga is equal to or less than a predetermined threshold value. An abnormality of the first arithmetic circuit 50 is detected based on whether or not there is any. If the deviation between the change amount of the integrated angle θi and the change amount of the absolute angle θga exceeds a predetermined threshold value, the absolute angle abnormality detection unit 146 indicates the absolute angle abnormality detection flag Fa that indicates the detection result of the abnormality in the first arithmetic circuit 50. To generate. On the other hand, the absolute angle abnormality detection unit 146 does not generate the absolute angle abnormality detection flag Fa when the deviation between the change amount of the integrated angle θi and the change amount of the absolute angle θga is equal to or less than the predetermined threshold. When the deviation between the change amount of the integrated angle θi and the change amount of the absolute angle θga exceeds a predetermined threshold value, the second arithmetic circuit 60 is relied on and an abnormality has occurred in the first arithmetic circuit 50. And

  Here, if an abnormality occurs in the absolute angle abnormality detection unit 146, it becomes impossible to detect the abnormality detection target of the absolute angle abnormality detection unit 146, that is, the first arithmetic circuit 50. Therefore, in this embodiment, an absolute angle BIST unit 147 that diagnoses the absolute angle abnormality detection unit 146 is provided.

  When diagnosing the absolute angle abnormality detection unit 146, the absolute angle BIST unit 147 provides a test signal indicating the variation amount of the integrated angle θi and the variation amount of the absolute angle θga that are defined so as to derive the abnormality detection result. It outputs to the angle abnormality detection unit 146, and operates so as to forcibly create a situation in which the absolute angle abnormality detection unit 146 generates the absolute angle abnormality detection flag Fa. Then, the absolute angle BIST unit 147 diagnoses the absolute angle abnormality detection unit 146 based on whether the absolute angle abnormality detection unit 146 has generated the absolute angle abnormality detection flag Fa. In this diagnosis, the absolute angle BIST unit 147 indicates a diagnosis result indicating that the absolute angle abnormality detection unit 146 is abnormal when the absolute angle abnormality detection unit 146 does not generate the absolute angle abnormality detection flag Fa. The flag F3 is generated. On the other hand, the absolute angle BIST unit 147 detects the absolute angle BIST abnormality when the absolute angle abnormality detection unit 146 generates the absolute angle abnormality detection flag Fa when the absolute angle abnormality detection unit 146 generates the absolute angle abnormality detection flag Fa. The flag F3 is not generated. The absolute angle BIST abnormality flag F3 generated by the absolute angle abnormality detection unit 146 is output to the BIST control unit 148.

The BIST control unit 148 controls execution of diagnosis by the BIST units of the first arithmetic circuit 50, the second arithmetic circuit 60, and the third arithmetic circuit 70.
The BIST control unit 148 outputs a command signal S1 to the counter BIST unit 110 when the counter BIST unit 110 diagnoses the counter abnormality detection unit 108. When the command signal S1 is input, the counter BIST unit 110 executes the diagnosis of the counter abnormality detection unit 108. When the counter BIST abnormality flag F1 is input from the counter BIST unit 110, the BIST control unit 148 diagnoses that the counter abnormality detection unit 108 is not abnormal, and ends the diagnosis of the counter abnormality detection unit 108. In this case, the BIST control unit 148 performs various operations so that the counter abnormality detection unit 108 forcibly created generates the counter abnormality flag Fc, that is, the abnormal operation state of the steering control unit 47 is released. The operating state of the steering control unit 47 is reset in order to erase information such as flags related to abnormality detection and each diagnosis.

  The BIST control unit 148 outputs a command signal S1a to the power supply BIST unit 109 when the voltage abnormality detection unit 107 is diagnosed by the power supply BIST unit 109. When the command signal S1a is input, the power supply BIST unit 109 executes the diagnosis of the voltage abnormality detection unit 107. When the power supply BIST abnormality flag F1a is input from the power supply BIST unit 109, the BIST control unit 148 diagnoses that the power supply abnormality detection unit 107 is not abnormal, and ends the diagnosis of the power supply abnormality detection unit 107. In this case, the BIST control unit 148 performs various operations such that the forcibly generated power supply abnormality detection unit 107 generates the power supply abnormality flag Fb, that is, the abnormal operation state of the steering control unit 47 is released. The operating state of the steering control unit 47 is reset in order to erase information such as flags related to abnormality detection and each diagnosis.

  When the first absolute angle information BIST unit 123 diagnoses the first absolute angle information abnormality detection unit 122, the BIST control unit 148 outputs a command signal S2a to the first absolute angle information BIST unit 123. When the command signal S2a is input, the first absolute angle information BIST unit 123 executes the diagnosis of the first absolute angle information abnormality detection unit 122. When the BIST control unit 148 receives the first absolute angle information BIST abnormality flag F2a from the first absolute angle information BIST unit 123, the BIST control unit 148 diagnoses that the first absolute angle information abnormality detection unit 122 is not abnormal, and determines the first absolute angle information. The diagnosis of the corner information abnormality detecting unit 122 is ended. In this case, the BIST control unit 148 determines that the forcibly created first absolute angle information abnormality detection unit 122 generates the first absolute angle information abnormality flag Faa, that is, the abnormal operation state of the steering control unit 47. The operating state of the steering control unit 47 is reset so as to erase information such as flags related to various abnormality detections and diagnoses so as to be released.

  When the second absolute angle information BIST unit 133 diagnoses the second absolute angle information abnormality detection unit 132, the BIST control unit 148 outputs a command signal S2b to the second absolute angle information BIST unit 133. When the command signal S2b is input, the second absolute angle information BIST unit 133 executes the diagnosis of the second absolute angle information abnormality detection unit 132. When the second absolute angle information BIST abnormality flag F2b is input from the second absolute angle information BIST unit 133, it is diagnosed that the second absolute angle information abnormality detection unit 132 is not abnormal, and the second absolute angle information abnormality detection unit 132 is detected. End the diagnosis of. In this case, the BIST control unit 148 determines that the forcibly created second absolute angle information abnormality detection unit 132 generates the second absolute angle information abnormality flag Fab, that is, the abnormal operation state of the steering control unit 47. The operating state of the steering control unit 47 is reset so as to erase information such as flags related to various abnormality detections and diagnoses so as to be released.

  When executing the diagnosis of the absolute angle abnormality detection unit 146 by the absolute angle BIST unit 147, the BIST control unit 148 outputs the command signal S3 to the absolute angle BIST unit 147. The absolute angle BIST unit 147 executes the diagnosis of the absolute angle abnormality detection unit 146 when the command signal S3 is input. When the absolute angle BIST abnormality flag F3 is input from the absolute angle abnormality detection unit 146, the BIST control unit 148 diagnoses that the absolute angle abnormality detection unit 146 is not abnormal and ends the diagnosis of the absolute angle abnormality detection unit 146. To do. In this case, the BIST control unit 148 is configured so that the forcibly created absolute angle abnormality detection unit 146 generates the absolute angle abnormality detection flag Fa, that is, the abnormal operation state of the steering control unit 47 is released. The operating state of the steering control unit 47 is reset in order to erase information such as flags related to various abnormality detections and diagnoses.

  When the BIST control unit 148 does not input the corresponding BIST abnormality flag despite executing the diagnosis by each BIST unit, the BIST control unit 148 shifts to the fail-safe control according to the situation. For example, if the BIST control unit 148 does not input the absolute angle BIST abnormality flag F3 from the absolute angle abnormality detection unit 146 despite executing the diagnosis of the absolute angle abnormality detection unit 146, the absolute angle abnormality detection unit 146 is abnormal. Is diagnosed, and the operation shifts to the fail-safe control for stopping the operation of the steering control unit 47.

  In the present embodiment, the execution timing of diagnosis of each BIST unit (counter BIST unit 110, power supply BIST unit 109, first absolute angle information BIST unit 123, second absolute angle information BIST unit 133, and absolute angle BIST unit 147) is set. Different from each other.

  As shown in FIG. 7, the BIST control unit 148 executes a diagnosis by each BIST unit during the initial check performed immediately after the start switch is turned on. That is, the BIST control unit 148 first outputs the command signal S1 to the counter BIST unit 110, so that the counter BIST unit 110 diagnoses the counter abnormality detection unit 108. The BIST control unit 148 outputs the command signal S1a to the power supply BIST unit 109 after the counter BIST unit 110 completes the diagnosis of the counter abnormality detection unit 108, that is, after acquiring the counter BIST abnormality flag F1 from the counter BIST unit 110. By doing so, the diagnosis of the voltage abnormality detection unit 107 by the power supply BIST unit 109 is executed. The BIST control unit 148 instructs the first absolute angle information BIST unit 123 after the diagnosis of the voltage abnormality detection unit 107 by the power supply BIST unit 109 is completed, that is, after the power supply BIST abnormality flag F1a is acquired from the power supply BIST unit 109. By outputting the signal S2a, the diagnosis of the first absolute angle information abnormality detection unit 122 by the first absolute angle information BIST unit 123 is executed. After the diagnosis of the first absolute angle information abnormality detection unit 122 by the first absolute angle information BIST unit 123 is completed, the BIST control unit 148 sets the first absolute angle information BIST abnormality flag F2a from the first absolute angle information BIST unit 123. After the acquisition, by outputting the command signal S2b to the second absolute angle information BIST unit 133, the diagnosis of the second absolute angle information abnormality detection unit 132 by the second absolute angle information BIST unit 133 is executed. After the diagnosis of the second absolute angle information abnormality detecting unit 132 by the second absolute angle information BIST unit 133 is completed, the BIST control unit 148 sets the second absolute angle information BIST abnormality flag F2b from the second absolute angle information BIST unit 133. After the acquisition, by outputting the command signal S3 to the absolute angle BIST unit 147, the absolute angle abnormality detection unit 146 is diagnosed by the absolute angle BIST unit 147. The BIST control unit 148 executes the diagnosis by each BIST unit after the diagnosis of the absolute angle abnormality detection unit 146 by the absolute angle BIST unit 147 is completed, that is, after the absolute angle BIST abnormality flag F3 is acquired from the absolute angle BIST unit 147. finish. Accordingly, the BIST control unit 148 executes the diagnosis in the order of the counter BIST unit 110, the power supply BIST unit 109, the first absolute angle information BIST unit 123, the second absolute angle information BIST unit 133, and the absolute angle BIST unit 147. The counter BIST unit 110, the power supply BIST unit 109, the first absolute angle information BIST unit 123, the second absolute angle information BIST unit 133, and the absolute angle BIST unit 147 are executed at the second rotation angle sensor 44, the first rotation angle sensor 44, and the first rotation angle sensor 44. The sampling timings of the pinion angle sensor 46a and the second pinion angle sensor 46b are different.

The operation and effect of this embodiment will be described.
(1) Diagnosis of an abnormality detection unit by each BIST unit (counter BIST unit 110, power supply BIST unit 109, first absolute angle information BIST unit 123, second absolute angle information BIST unit 133, and absolute angle BIST unit 147) After that, the steering control unit 47 including the abnormality detection unit that is the diagnosis target has its operating state set to the state in which the abnormality is detected. In order to cancel the state in which this abnormality is detected, it is necessary to reset the operating state of the steering control unit 47.

  Then, as in the present embodiment, when the plurality of BIST units must perform the diagnosis of the plurality of abnormality detection units, the diagnosis by the other BIST units is performed while the diagnosis by any one of the BIST units is being performed. When the operating state of the steering control unit 47 is reset, the diagnosis result may not be obtained correctly.

  In this respect, according to the present embodiment, the execution timing of the diagnosis of each BIST unit is different from each other. Therefore, the steering control unit is accompanied by the execution of the diagnosis by another BIST unit during the execution of the diagnosis by each BIST unit. It is possible to suppress the occurrence of a situation where the operating state of 47 is reset. As a result, the reliability of the diagnosis of the abnormality detecting unit targeted by each BIST unit can be improved. Therefore, the reliability of the calculation of the pinion angle θpa as the absolute angle by the steering control unit 47 can be improved.

  (2) Further, as described in (1) above, the BIST unit performs diagnosis at the sampling timing of the detection results of the second rotation angle sensor 44, the first pinion angle sensor 46a, and the second pinion angle sensor 46b. If the operation state of the steering control unit 47 is reset along with the execution, sampling of the detection results by the second rotation angle sensor 44, the first pinion angle sensor 46a, and the second pinion angle sensor 46b may not be correctly executed. There is.

  In order to deal with this, in the present embodiment, the execution timing of the diagnosis of the counter BIST unit 110, the power supply BIST unit 109, the first absolute angle information BIST unit 123, the second absolute angle information BIST unit 133, and the absolute angle BIST unit 147. Are different from the sampling timings of the second rotation angle sensor 44, the first pinion angle sensor 46a, and the second pinion angle sensor 46b. From this, it is possible to suppress the occurrence of a situation in which the operation state of the steering control unit 47 is reset due to the execution of the diagnosis by each BIST unit at the sampling timing. As a result, the reliability of sampling the detection results of the second rotation angle sensor 44, the first pinion angle sensor 46a, and the second pinion angle sensor 46b can be improved.

  (3) The integrated angle θi and the absolute angle θga used when the abnormality is detected by the absolute angle abnormality detection unit 146 are changed according to the operation of the steering motor 41. Therefore, the changes in the integrated angle θi and the absolute angle θga are related to each other. Therefore, the absolute angle abnormality detection unit 146 can detect the abnormality of the first arithmetic circuit 50 by using the change amount of the integrated angle θi and the change amount of the absolute angle θga.

  (4) In the steer-by-wire type steering device of the present embodiment, in order to generate the motor control signal Sm required to drive the steering motor 41, the steering shaft 12 (steering wheel 11) when the clutch 21 is engaged. It is necessary to obtain the pinion angle θpa that is the absolute angle of the first pinion shaft 13 that rotates in conjunction with the rotation of the. That is, according to the present embodiment, it is possible to realize the steering device 10b that can improve the reliability of the calculated pinion angle θpa of the first pinion shaft 13.

The present embodiment may be modified as follows. Further, the following other embodiments can be combined with each other within a technically consistent range.
The clutch control unit 22, the reaction force control unit 35, and the steering control unit 47 may be configured as a single control unit (ECU: electronic control unit).

  The first arithmetic circuit 50 and the second arithmetic circuit 60 are ASICs that execute a predetermined arithmetic operation on a specific input, but the present invention is not limited to this. For example, the first arithmetic circuit 50 and the second arithmetic circuit 60 may be realized by a microcomputer including a microprocessing unit or the like. Further, the first arithmetic circuit 50 and the second arithmetic circuit 60 may read the program stored in the storage unit and execute the arithmetic according to the program. Further, the first arithmetic circuit 50 and the second arithmetic circuit 60 may be realized by a low power consumption microcomputer specialized for a specific function. Even in this case, the configuration of the first arithmetic circuit 50 and the second arithmetic circuit 60 can be made simpler than that of the third arithmetic circuit 70, because it is specialized for a specific function.

  The first rotation angle sensor 33, the second rotation angle sensor 44, the first pinion angle sensor 46a, and the second pinion angle sensor 46b may be, for example, sensors using Hall elements, or sensors using resolvers. May be

  The first rotation angle sensor 33 and the second rotation angle sensor 44 may detect the rotation angles of the steering shaft 12 and the first pinion shaft 13, for example. For example, the rotation angle of the first pinion shaft 13 can be converted into a multi-turn rotation angle of the steering motor 41 in consideration of the reduction ratio between the steering motor 41 and the first pinion shaft 13. ..

  The first rotation angle sensor 33 is provided on the reaction force motor 31, but may be provided on the steering shaft 12 that is the rotation axis of the steering wheel 11. Further, although the second rotation angle sensor 44 is provided in the steering motor 41, it may be provided in the first pinion shaft 13 or the second pinion shaft 43.

  The first calculation circuit 50 calculates the count value C even when the start switch is in the on state, but may not calculate the count value C when the start switch is in the on state.

The third arithmetic circuit 70 may take in the electric signal Sb of the second rotation angle sensor 44 via the first arithmetic circuit 50.
The absolute angle abnormality detection unit 146 detects the abnormality of the first arithmetic circuit 50 based on whether the deviation between the change amount of the integrated angle θi and the change amount of the absolute angle θga is less than or equal to a predetermined threshold value. It is not limited to this. For example, the absolute angle abnormality detection unit 146 may detect the abnormality of the first arithmetic circuit 50 based on whether or not the deviation between the integrated angle θi and the absolute angle θga is less than or equal to a predetermined value.

  -Instead of the first pinion angle sensor 46a and the second pinion angle sensor 46b, the steering device 10 detects the absolute position in the axial direction of the steered shaft 14, and the axis of the steered shaft 14 is determined based on the change in the absolute position. A stroke sensor for detecting the amount of movement in the direction may be provided. Since there is a correlation between the amount of movement of the steered shaft 14 and the rotation angle θb of the steered motor 41, the absolute angle output unit 143 determines the motor midpoint of the steered motor 41 from the amount of movement of the steered shaft. You can ask. Therefore, the absolute angle output unit 143 sets the rotation angle θb of the steering motor 41 to 360 based on the change amount of the rotation angle θb of the steering motor 41 from the reference point with the motor middle point of the steering motor 41 as the reference point. It is possible to calculate with an absolute angle in a range exceeding degrees, and to calculate the pinion angle θpa with an absolute angle based on the calculated rotation angle θb (absolute angle).

  A stroke sensor may be provided in addition to the first pinion angle sensor 46a and the second pinion angle sensor 46b. For example, in the third arithmetic circuit 70, either one of the absolute angle θga calculated by the absolute angle calculator 141 and the rotation angle of the first pinion shaft 13 obtained based on the moving amount of the steered shaft 14 is set. A switching unit that outputs to the absolute angle output unit 143 is provided. When an abnormality occurs in the TAS 46, for example, the switching unit replaces the first absolute angle information θg1 and the second absolute angle information θg2 with the first pinion shaft obtained based on the moving amount of the steered shaft 14. The rotation angle of 13 is output to the absolute angle output unit 143.

The power BIST unit 109 may be omitted from the configuration of the first arithmetic circuit 50.
The BIST control unit 148 causes the counter BIST unit 110, the power supply BIST unit 109, the first absolute angle information BIST unit 123, the second absolute angle information BIST unit 133, and the absolute angle BIST unit 147 to execute diagnosis in this order. The order may be changed as appropriate, and the execution timing of the diagnosis of each BIST unit may be different from each other.

  -The counter BIST unit 110, the power supply BIST unit 109, the first absolute angle information BIST unit 123, the second absolute angle information BIST unit 133, and the absolute angle BIST unit 147 are executed at the second rotation angle sensor 44, It may be determined without considering the sampling timings of the first pinion angle sensor 46a and the second pinion angle sensor 46b.

  When the deviation between the change amount of the integrated angle θi and the change amount of the absolute angle θga exceeds a predetermined threshold, the absolute angle abnormality detection unit 146 has an abnormality in both the first arithmetic circuit 50 and the second arithmetic circuit 60. As a thing, you may generate the absolute angle abnormality detection flag Fa which shows abnormality of both the 1st arithmetic circuit 50 and the 2nd arithmetic circuit 60. When the reliability of the first arithmetic circuit 50 is higher than that of the second arithmetic circuit 60, the absolute angle abnormality detection unit 146 determines that the deviation between the change amount of the integrated angle θi and the change amount of the absolute angle θga is a predetermined threshold value. When it exceeds, the absolute angle abnormality detection flag Fa indicating the abnormality of the second arithmetic circuit 60 may be generated.

  The power supply BIST unit 109 changes the voltage by changing the upper limit value of the predetermined voltage range assumed for the voltage abnormality detection unit 107 to detect the abnormality of the control voltage Vco when diagnosing the voltage abnormality detection unit 107. Although the abnormality detection unit 107 forcedly creates a situation in which the voltage abnormality flag Fb is generated, the situation is not limited to this. For example, the power supply BIST unit 109 is based on whether or not the voltage abnormality detection unit 107 has generated the voltage abnormality flag Fb when the voltage abnormality detection unit 107 transmits a test signal specified to derive the abnormality result. The voltage abnormality detection unit 107 may forcibly create a situation in which the voltage abnormality flag Fb is generated.

  A belt transmission mechanism and a ball screw mechanism may be adopted as a transmission mechanism that transmits the power generated by the steering motor 41 to the steering shaft 14, instead of the second reduction gear mechanism 42 and the second pinion shaft 43.

The TAS 46 is provided with the pinion torque sensor 46c, but may be only the first pinion angle sensor 46a and the second pinion angle sensor 46b.
The TAS 46 is provided on the first pinion shaft 13 but may be provided on the steering shaft 12. In this case, the TAS 46 is an absolute angle sensor that detects the rotation angle of the steering shaft 12 as an absolute angle. The configuration of the above embodiment applied to the steering control unit 47 may be applied to the reaction force control unit 35.

  The steering device 10 may have a configuration in which the clutch 21 and the clutch control unit 22 are omitted. In this case, power transmission between the steering wheel 11 and the steered wheels 16, 16 is always maintained in a separated state. However, it is possible to construct a steering device (steering unit) capable of supporting both the first type having the clutch 21 and the second type not having the clutch 21 as the steering device 10.

  The reaction force control unit 35 or the steering control unit 47 may be applied to the control device of the electric power steering device that applies the torque of the motor as an assist force to the steering mechanism of the vehicle. The electric power steering device may be a type that applies an assist force to the steering shaft or a type that applies an assist force to the steered shaft.

  The vehicle on which the steering device 10 (steering device 10b) is mounted may be a vehicle having a so-called internal combustion engine that employs an engine as a vehicle drive source, or a so-called electric vehicle that employs a motor as a vehicle drive source. It may be. The start switch in the case of an electric vehicle is a switch that starts a motor as a vehicle drive source.

  The reaction force control unit 35 or the steering control unit 47 is not limited to the steering device 10, and may be embodied as a control device for a mechanical device using a motor as a power source.

  10... Steering device, 10b... Steering device, 12... Steering shaft, 13... First pinion shaft, 14... Steering shaft, 16... Steering wheel, 21... Clutch, 31... Reaction force motor, 33... First rotation angle Sensor, 35... Reaction force control unit, 41... Steering motor, 43... Second pinion shaft, 44... Second rotation angle sensor, 46... TAS, 46a... First pinion angle sensor, 46b... Second pinion angle sensor, 46c... Pinion torque sensor, 47... Steering control unit, 50... First arithmetic circuit, 60... Second arithmetic circuit, 70... Third arithmetic circuit, 80... Driving circuit, 90... Battery, 100... Power supply circuit, 101... Counter circuit, 106... Count value calculation section, 107... Voltage abnormality detection section, 108... Counter abnormality detection section, 109... Power source BIST section, 110... Counter BIST section, 120... First absolute angle information calculation circuit, 121... First Absolute angle information calculation unit, 122... First absolute angle information abnormality detection unit, 123... First absolute angle information BIST unit, 130... Second absolute angle information calculation circuit, 131... Second absolute angle information calculation unit, 132... 2 Absolute angle information abnormality detection unit, 133... Second absolute angle information BIST unit, 140... Integrated angle calculation unit, 141... Absolute angle calculation unit, 143... Absolute angle output unit, 144... Steering angle command value calculation unit, 145 Current feedback control unit, 146... Absolute angle abnormality detection unit, 147... Absolute angle BIST unit, 148... BIST control unit, θg, θga... Absolute angle, θi... Accumulated angle, I*... Current command value, S1, S1a, S2a, S2b, S3... Command signal, Sa, Sb, Sg1, Sg2... Electric signal, Sm... Motor control signal, θpa, θpb... Pinion angle, Tp... Torque, Th... Steering torque, U2... Steering unit, V... Vehicle speed, Vco... Control voltage, θ*... Target steering angle, θs... Steering angle, θt... Steering angle.

Claims (4)

A counter unit that calculates a count value that is a value for calculating an integrated angle obtained by integrating the relative angle of the motor based on the detection result of the first sensor that detects the relative angle of the motor that is the power source of the mechanical device; A first arithmetic circuit having a first abnormality detecting section for detecting an abnormality of the counter section and a first BIST section for diagnosing the first abnormality detecting section;
Absolute position information calculation that calculates absolute position information that is a value for calculating the absolute position of the detection target based on the detection result of the second sensor that detects the absolute position of the detection target that interlocks with the motor in the mechanical device. And a second BIST unit for diagnosing the second abnormality detection unit, and a second abnormality detection unit for detecting an abnormality of the absolute position information calculation unit,
An integrated angle calculation unit that calculates the integrated angle using the count value, an absolute angle calculation unit that calculates the absolute angle of a rotary shaft that is interlocked with the motor using the absolute position information, the integrated angle and the absolute value. Third calculation having a third abnormality detection unit that detects an abnormality of at least one of the first calculation circuit and the second calculation circuit based on a comparison of angles, and a third BIST unit that diagnoses the third abnormality detection unit Section and
An angle calculation device in which execution timings of diagnosis by the first BIST unit, the second BIST unit, and the third BIST unit are different from each other.   The angle calculation device according to claim 1, wherein execution timing of diagnosis by the first BIST unit, the second BIST unit, and the third BIST unit is different from sampling timing of detection results by the first sensor and the second sensor.   The third abnormality detection unit uses at least one of the first arithmetic circuit and the second arithmetic circuit by using a variation amount of the integrated angle per unit time and a variation amount of the absolute angle per unit time. The angle calculation device according to claim 1, which detects an abnormality. A steering apparatus comprising the angle calculation device according to any one of claims 1 to 3 and a steering unit as the mechanical device,
The steering unit is
A steering shaft that steers the steered wheels by making a linear motion,
A pinion shaft meshed with the steering shaft;
A steering motor that is a generation source of power applied to the steering shaft,
A transmission mechanism that transmits the power generated by the steering motor to the steering shaft,
The steering device in which the detection target is the pinion shaft provided so as to interlock with the steering motor.