JP7342729B2 - Control device - Google Patents

Description

The present invention relates to a control device.

Conventionally, rotation angle detection devices that detect the rotation angle of a motor are known. For example, in Patent Document 1, by continuing to calculate the number of rotations even while the ignition switch is off, the steering angle is calculated based on the rotation angle, the number of rotations, and the gear ratio between the motor and the steering shaft. There is.

Patent No. 5958572

Since the number of rotations is an integrated value of motor rotations, it is necessary to continue detection even when the vehicle is stopped. Therefore, in Patent Document 1, power supply to the rotation angle detection device is continued even when the ignition switch is turned off. are doing. Therefore, there is a risk that the battery will run out due to power consumption while the ignition switch is turned off.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a control device that can continue detecting rotational positions for multiple rotations even when power supply is interrupted.

The control device of the present invention includes a detection device (401, 402), a control section (70) that controls driving of the motor, and a motor rotation angle sensor (85) that detects the rotation angle of the motor. The detection device includes a multi-turn detection section (45, 145, 245), a position detection section (40, 41, 42, 141, 142, 241, 242, 85), and a multi-rotation position calculation section (55, 155, 255) and angle calculation units (50, 51, 52, 151, 152, 251, 252).

The multi-turn detection unit is capable of continuously detecting the rotational position of the detection target (92) driven by the motor (80) over multiple rotations without external power supply. The position detection section detects a rotational position during one rotation. The multiple rotation position calculation section calculates multiple rotation position information regarding the rotation positions of multiple rotations based on the detection value of the multiturn detection section. The angle calculation unit calculates rotation angle information regarding a rotational position during one rotation based on the detected value of the position detection unit. The multi-turn detection section is provided at a location different from the motor. Thereby, even if the external power supply is cut off, detection of rotational positions for multiple rotations can be continued.
The detection device or the control unit includes an absolute position calculation unit (75) that calculates an absolute position, which is the amount of displacement of the detection target from a reference position, based on the multiple rotation position information and rotation angle information. The absolute position calculation section calculates the absolute position on the detection target side, which is calculated based on the detection values of the multiturn detection section and the position detection section, and the motor side, which is calculated based on the detection value of the motor rotation angle sensor. Calculate absolute position.
The control unit includes an abnormality monitoring unit (77) that monitors abnormalities based on the absolute position on the detection target side and the absolute position on the motor side. If the difference between the absolute position on the detection target side and the absolute position on the motor side is greater than or equal to the abnormality judgment value, and there is no history of abnormality in the detection device and the control unit, the abnormality monitoring unit detects the connection between the detection target of the multiturn detection unit and the motor. It is determined that there is a misalignment in the connection between the two.

FIG. 1 is a schematic configuration diagram of a steering system according to a first embodiment. FIG. 2 is an exploded perspective view of the sensor unit according to the first embodiment. FIG. 2 is a block diagram showing a detection device and an ECU according to the first embodiment. FIG. 2 is a block diagram showing a detection device and an ECU according to the first embodiment. It is a schematic diagram explaining the gear fixing mechanism by 1st Embodiment. FIG. 3 is an explanatory diagram showing the relationship between rotational position and count value according to the first embodiment. 7 is a flowchart illustrating midpoint learning processing according to the first embodiment. FIG. 7 is a side view showing a detection device according to a second embodiment. FIG. 7 is a side view showing a detection device according to a third embodiment. FIG. 7 is a side view showing a detection device according to a fourth embodiment. It is a side view which shows the detection apparatus by 5th Embodiment. FIG. 3 is a block diagram showing a detection device and an ECU according to a sixth embodiment. FIG. 3 is a block diagram showing a detection device and an ECU according to a seventh embodiment. It is a flowchart explaining abnormality detection processing by a 7th embodiment. It is a block diagram showing a rotation angle sensor and an ECU according to an eighth embodiment. It is a flowchart explaining abnormality monitoring processing by an 8th embodiment. FIG. 7 is a block diagram showing a rotation angle sensor and an ECU according to a ninth embodiment. It is an explanatory view explaining abnormality identification by a 9th embodiment. FIG. 3 is a block diagram showing a rotation angle sensor and an ECU according to a tenth embodiment. FIG. 12 is a block diagram showing a rotation angle sensor and an ECU according to an eleventh embodiment. It is a block diagram showing a rotation angle sensor and an ECU according to a twelfth embodiment. FIG. 12 is a block diagram showing a rotation angle sensor and an ECU according to a thirteenth embodiment.

Hereinafter, a detection device and a control device according to the present invention will be explained based on the drawings. Hereinafter, in a plurality of embodiments, substantially the same configurations are denoted by the same reference numerals, and description thereof will be omitted.

(First embodiment)
A detection device and a control device according to the first embodiment are shown in FIGS. 1 to 7. FIG. 1 shows the overall configuration of a steering system 90 including an electric power steering device 8. As shown in FIG. The steering system 90 includes a steering wheel 91 that is a steering member, a steering shaft 92, a pinion gear 96, a rack shaft 97, wheels 98, an electric power steering device 8, and the like.

Steering wheel 91 is connected to steering shaft 92 . The steering shaft 92 has an input shaft 11 that is a first shaft and an output shaft 12 that is a second shaft (see FIG. 2). The steering shaft 92 is provided with a sensor unit 4 that detects steering torque.

A pinion gear 96 is provided at the tip of the steering shaft 92. The pinion gear 96 meshes with the rack shaft 97. A pair of wheels 98 are connected to both ends of the rack shaft 97 via tie rods or the like. When the driver rotates the steering wheel 91, a steering shaft 92 connected to the steering wheel 91 rotates. The rotational motion of the steering shaft 92 is converted into linear motion of the rack shaft 97 by the pinion gear 96. The pair of wheels 98 are steered to an angle corresponding to the amount of displacement of the rack shaft 97.

The electric power steering device 8 includes a drive device 400 having a motor 80 and an ECU 10, a sensor unit 4, a reduction gear 89 serving as a power transmission unit that reduces the rotation of the motor 80, and transmits the reduced rotation to a steering shaft 92. The electric power steering device 8 of this embodiment is of a so-called “column assist type,” but may also be of a so-called “rack assist type” in which rotation of the motor 80 is transmitted to the rack shaft 97. In this embodiment, the steering shaft 92 corresponds to the "driving object". If the mechanical portion from the steering wheel 91 to the wheels 98 is referred to as a "steering system", then the reduction gear 89 can be said to be a member that connects the motor 80 and the steering system.

The motor 80 outputs part or all of the torque required for steering, is driven by power supplied from a battery (not shown), and rotates the reduction gear 89 in forward and reverse directions. The drive device 400 is a so-called "mechanical and electrical integrated type" in which the ECU 10 is integrally provided on one side of the motor 80 in the axial direction, but the motor 80 and the ECU 10 may be provided separately. The ECU 10 is disposed coaxially with the axis of a motor shaft (not shown) on the opposite side of the output shaft of the motor 80. The ECU 10 may be provided on the output shaft side of the motor 80. By adopting a mechanical and electrical integrated type, the ECU 10 and the motor 80 can be efficiently arranged in a vehicle with limited mounting space.

The motor 80 is a three-phase brushless motor, and includes a first motor winding 180 and a second motor winding 280, which are a winding set wound around a rotor (not shown) (see FIG. 4). The motor windings 180 and 280 have the same electrical characteristics, and are wound around a common stator in a manner offset from each other by 30 [deg] in electrical angle. Accordingly, the motor windings 180 and 280 are controlled so that phase currents having a phase φ shifted by 30 [deg] are energized. Output torque is improved by optimizing the energization phase difference. Further, the sixth-order torque ripple can be reduced. Furthermore, since current is averaged by phase difference energization, it is possible to maximize the merit of canceling noise and vibration. Furthermore, since heat generation is also averaged, it is possible to reduce temperature-dependent inter-system errors such as detection values and torque of each sensor, and it is also possible to average the amount of current that can be passed. Note that the motor windings 180 and 280 may have different electrical characteristics.

As shown in FIG. 2, the sensor unit 4 includes an input shaft 11, an output shaft 12, a torsion bar 13, a multipolar magnet 15, a magnetic yoke 16, a detection device 401, and the like. The torsion bar 13 is fixed to the input shaft 11 at one end and to the output shaft 12 at the other end with a fixing pin 14, and connects the input shaft 11 and the output shaft 12 coaxially with the rotation axis O. The torsion bar 13 is a rod-shaped elastic member and converts torque applied to the steering shaft 92 into torsional displacement. The multipolar magnet 15 is formed into a cylindrical shape and is fixed to the input shaft 11. The multipolar magnet 15 is magnetized alternately into north poles and south poles in the circumferential direction. In this embodiment, the number of north and south poles is 12 pairs, for a total of 24 poles.

The magnetic yoke 16 is held by a yoke holding member (not shown) made of a non-magnetic material such as resin, and forms a magnetic circuit within the magnetic field generated by the multipolar magnet 15. The magnetic yoke 16 includes a first yoke 17 provided on the input shaft 11 side and a second yoke 18 provided on the output shaft 12 side. The first yoke 17 and the second yoke 18 are both annularly formed of soft magnetic material and are fixed to the output shaft 12 on the radially outer side of the multipolar magnet 15. The first yoke 17 has a ring portion 171 and a claw 172. The claws 172 are provided along the inner edge of the ring portion 171 at equal intervals around the entire circumference. The second yoke 18 has a ring portion 181 and a claw 182. The claws 182 are provided along the inner edge of the ring portion 181 at equal intervals around the entire circumference.

The number of pawls 172 and 182 is the same as the number of pole pairs of the multipolar magnet 15 (12 in this embodiment), and the pawls 172 and 182 are alternately arranged with a shift in the circumferential direction, and the first yoke 17 and the second yoke The yoke 18 faces each other with an air gap interposed therebetween. When no torsional displacement occurs in the torsion bar 13, that is, when no steering torque is applied to the steering shaft 92, the centers of the pawls 172 and 182 coincide with the boundary between the N and S poles of the multipolar magnet 15. It is arranged like this.

The magnetic flux collecting rings 21 and 22 are arranged radially outside the magnetic yoke 16 and collect magnetic flux from the magnetic yoke 16. The first magnetic flux collecting ring 21 is provided on the input shaft 11 side, and the second magnetic flux collecting ring 22 is provided on the output shaft 12 side. The first magnetic flux collecting ring 21 and the second magnetic flux collecting ring 22 are held by a magnetic flux collecting ring holding member (not shown) by insert molding or the like.

The first magnetism collecting ring 21 is made of a soft magnetic material and includes a ring portion 211 formed in a substantially annular shape, and two magnetism collecting portions 215 protruding radially outward from the ring portion 211. Like the first magnetic flux collecting ring 21, the second magnetic flux collecting ring 22 is made of a soft magnetic material, and includes a ring portion 221 formed in a substantially annular shape, and two magnetic flux collecting rings protruding outward in the radial direction from the ring portion 221. 225. The magnetic flux collecting part 215 of the first magnetic flux collecting ring 21 and the magnetic flux collecting part 225 of the second magnetic flux collecting ring 22 are provided so that opposing surfaces thereof are substantially parallel. A torque sensor 421 is arranged between the magnetic flux collectors 215 and 225.

The torque sensor 421 includes a magnetic detection element such as a Hall element, and detects the magnetic flux between the magnetic flux collectors 215 and 225. When no steering torque is applied between the input shaft 11 and the output shaft 12, the centers of the claws 172 of the first yoke 17 and the claws 182 of the second yoke 18 are aligned with the N and S poles of the multipolar magnet 15. is placed to match the boundaries of At this time, since the same number of lines of magnetic force enter and leave the claws 172 and 182 from the N and S poles of the multipolar magnet 15, the lines of magnetic force form a closed loop inside the first yoke 17 and the second yoke 18, respectively. . Therefore, no magnetic flux leaks into the gap between the yokes 17 and 18, and the magnetic flux density detected by the magnetic detection element becomes zero.

When steering torque is applied between the input shaft 11 and the output shaft 12 and torsional displacement occurs in the torsion bar 13, the multipolar magnet 15 fixed to the input shaft 11, the yoke 17 fixed to the output shaft 12, 18 is shifted in the circumferential direction. As a result, the magnetic flux density passing through the magnetic detection element is approximately proportional to the amount of torsional displacement of the torsion bar 13, and its polarity is reversed depending on the torsional direction of the torsion bar 13. The magnetic detection element detects the strength of the magnetic field in the thickness direction of the torque sensor 421, and outputs the strength of the detected magnetic field to the ECU 10 as a steering torque detection value.

The detection device 401 includes a substrate 411, a rotation angle sensor 31, and a torque sensor 421. The rotation angle sensor 31 and the torque sensor 421 are mounted on the substrate 411. The torque sensor 421 is placed closer to one side of the substrate 411 and inserted between the magnetic flux collectors 215 and 225. By cutting out the substrate 411 at the position where the magnetic collecting parts 215 and 225 are arranged and inserting the magnetic collecting part 225 into the notch, the distance between the magnetic collecting parts 215 and 225 can be reduced, thereby reducing the magnetic circuit gap. Can be made smaller. This reduces magnetic flux leakage and improves torque detection accuracy.

As shown in FIGS. 3 and 4, the rotation angle sensor 31 includes a position detection section 40, a multi-turn detection section 45, an angle calculation section 50, a count calculation section 55, and a communication section 58. When a starting switch such as an ignition switch is turned on, power is supplied from the power source 391. The power source 391 is, for example, a constant voltage power source such as a regulator. Hereinafter, the starting switch will be referred to as "IG" as appropriate.

The position detection unit 40 detects the rotation of the detection gear 27 that meshes with the output shaft gear 26 that rotates together with the output shaft 12 (see FIG. 2). The detection gear 27 is provided with a magnet 28, and the position detection unit 40 detects a change in the magnetic field of the magnet 28 according to the rotation of the detection gear 27. The position detection unit 40 is, for example, a magnetoresistive element such as an AMR sensor, a TMR sensor, or a GMR sensor, a Hall element, or the like. Alternatively, an inductive sensor, a resolver, or the like may be used.

The gear ratio between the output shaft gear 26 and the detection gear 27 can be set arbitrarily, and the resolution is determined according to the gear ratio. For example, if the gear ratio between the output shaft gear 26 and the detection gear 27 is 2:1, the detection gear 27 rotates twice for one rotation of the steering shaft 92, allowing highly accurate detection. Moreover, if the detection gear 27 is made larger than the output shaft gear 26, it becomes unnecessary to detect the number of rotations.

The multi-turn detection unit 45 is configured to be able to detect changes in magnetic flux accompanying the rotation of the magnet 28 even without power supply. In other words, the multi-turn detection unit 45 uses a storage method other than electricity (in this embodiment, a magnetic storage method). Specifically, in the multi-turn detection section 45, magnetic detection elements are arranged in a spiral shape, and are initially oriented in a specific magnetic direction. When the magnet 28 rotates, the magnetic direction of the magnetic detection element is changed sequentially from the end, and the location where the magnetic flux changes outward or inward changes each time the detection gear 27 rotates, depending on the rotation direction. The resistance value of the magnetic detection element changes depending on the magnetic direction. No electric power is required to change the magnetic direction of the magnetic sensing element. Furthermore, the rotational position of the detection gear 27 can be measured by passing a current through the magnetic detection element and detecting the output. That is, the multi-turn detection section 45 does not require electric power during detection, but requires electric power when reading out the detected value.

The multi-turn detection unit 45 may be capable of detecting a predetermined number of rotational positions from the start end to the end, or may be configured to be able to detect an infinite number of rotational positions by connecting the start end and the end. You may.

The angle calculation unit 50 calculates a gear rotation angle θg, which is the rotation angle of the detection gear 27, based on the detection value of the position detection unit 40 that has been AD converted by an AD conversion unit (not shown). The gear rotation angle θg is a value according to the rotation angle of the detection gear 27, and may be any value that can be converted into a rotation angle.

The count calculation section 55 calculates a count value TC according to the output when the multi-turn detection section 45 is energized. The count value TC is counted up or down n times (n is an integer of 1 or more) during one rotation of the detection gear 27, depending on the rotation direction.

In order to prevent a detection error when gear rotation angle θg changes from gear rotation angle θg=359° at count value TC=k to gear rotation angle θg=0° at count value TC=k+1, n=2 or more. It is desirable that one rotation of the detection gear 27 should be 2 counts or more. Furthermore, the detection deviation between the gear rotation angle θg and the count value TC due to switching between 359° and 0° is corrected as appropriate. Note that, for the sake of simplification, the decimal part of the gear rotation angle θg has been omitted from the explanation here.

If n is 3 or more, the direction of rotation can be detected. In this embodiment, n=4, and the count is counted up or down every time the detection gear 27 rotates by 90[deg]. In this embodiment, it is assumed that the count value TC is counted up when the steering wheel 91 rotates in the forward direction, and counted down when the steering wheel 91 is rotated in the reverse direction. Further, sampling is performed at a speed sufficient for the rotational speed of the detection gear 27. In FIG. 4, blocks surrounded by two-dot chain lines do not require power, and blocks surrounded by broken lines are supplied with power when the IG is turned on.

The communication unit 58 generates an output signal including the gear rotation angle θg and the count value TC, and outputs the output signal to the control unit 70 by digital communication such as SPI communication. The communication method may be a method other than SPI communication, such as SENT communication. Further, the gear rotation angle θg and the count value TC may be separately output to the control unit 70. Furthermore, the absolute angle θa may be calculated based on the gear rotation angle θg and the count value TC, and the absolute angle θa may be output to the control unit 70.

The ECU 10 includes drive circuits 120 and 220, a control section 70, a motor rotation angle sensor 85, and the like. In FIG. 4, the drive circuit is indicated as "INV". The first drive circuit 120 is a three-phase inverter having six switching elements and converts the power supplied to the first motor winding 180. The second drive circuit 220 is a three-phase inverter having six switching elements and converts the power supplied to the second motor winding 280. The switching elements constituting the drive circuits 120 and 220 are turned on and off based on control signals output from the control section 70.

The motor rotation angle sensor 85 detects the magnetic field of a magnet that rotates together with a rotor (not shown) in response to the rotation of the motor 80, and includes, for example, a magnetoresistive element such as an AMR sensor, a TMR sensor, or a GMR sensor. , Hall element, etc. Alternatively, an inductive sensor, a resolver, or the like may be used.

The control unit 70 is mainly composed of a microcomputer, and internally includes a CPU, ROM, RAM, I/O, and a bus line connecting these components, all of which are not shown. Each process in the control unit 70 may be a software process in which a CPU executes a program stored in a physical memory device such as a ROM (i.e., a readable non-temporary tangible recording medium), or It may also be a hardware process using a dedicated electronic circuit. The same applies to control units 170 and 270 according to embodiments described later.

The control unit 70 includes an absolute angle calculation unit 75, a control calculation unit 76, an abnormality monitoring unit 77, and the like. The absolute angle calculation section 75 calculates the absolute angle θa using the count value TC and the gear rotation angle θg. The absolute angle θa is the rotation angle of the detection gear 27 from the reference position, and includes multiple rotation information. By converting the absolute angle θa by the gear ratio of the gears 26 and 27, the steering angle θs can be calculated. Hereinafter, the term "absolute angle" refers to the rotation angle of the detection target from the reference position, and is a value that includes multiple rotation information.

The control calculation unit 76 performs various control calculations using information acquired from the rotation angle sensor 31, the motor rotation angle sensor 85, and the like. In this embodiment, control calculations related to drive control of the motor 80 are performed using information acquired from the detection device 401 and the motor rotation angle sensor 85. The abnormality monitoring unit 77 monitors the detection device 401 and the motor rotation angle sensor 85 for abnormalities.

The calculation of the steering angle θs is shown in equation (1). INT(TC/n) in the formula means the integer part of the quotient obtained by dividing the count value TC by the number of counts per rotation n, and indicates the number of rotations of the detection gear 27. If the 0 points of count value TC and gear rotation angle θg are different, the wrong number of rotations will be calculated in INT (TC/n), so if necessary, set count value TC and gear rotation angle θg. The calculation may be performed after adding the TC correction value TC_c for matching the 0 points of . In that case, the number of rotations is INT{(TC+TC_c)/n}. The TC correction value TC_c needs to be calculated every time the count value TC is reset, and the TC correction value TC_c is stored in a non-volatile area. In the example of FIG. 4, the absolute angle calculation unit 75 is provided in the control unit 70, but the rotation angle sensor 31 may calculate the absolute angle θa and output the absolute angle θa to the control unit 70. . Alternatively, the steering angle θs may be used after converting the gear ratio. The same applies to the embodiments described below. Moreover, Rg in the formula is the gear ratio of gears 26 and 27.

θs={INT(TC/n)×360+θg}/Rg...(1)

The steering shaft 92 makes two left and right turns from the neutral position, that is, four turns from the left rotation end to the right rotation end. Further, when the gear ratio of the output shaft gear 26 and the detection gear 27 is set to 2:1 and the steering shaft 92 is rotated from one end to the other end, the detection gear 27 rotates eight times. Furthermore, in this embodiment, the number of counts during one rotation of the detection gear 27 is n=4, so the multi-turn detection unit 45 is configured to be able to detect 8×4=32 counts or more.

If the number of counts that can be detected by the multi-turn detection section 45 is increased more than necessary, the circuit scale will increase, and the size and cost of the IC will increase. Furthermore, if there is a sticking mode in which counting is not possible when the count value TC of the multi-turn detector 45 reaches the minimum value Cmin or the maximum value Cmax, the neutral position of the steering wheel 91 and the median value Cmid of the multi-turn detector 45 may deviate from each other. If so, there is a risk that the absolute angle θa and the steering angle θs will not be calculated appropriately (see FIG. 6).

In this embodiment, as shown in FIG. 5, the sensor unit 4 is provided with a gear fixing mechanism 29 that can fix the output shaft gear 26 and the detection gear 27. Since the multi-turn detection section 45 is of a magnetic storage type, the gear fixing mechanism 29 is formed of something that does not have a magnetic field. In this embodiment, the detection device 401, the detection gear 27, and the output shaft gear 26 are positioned so that the count value TC becomes a specific value (for example, the median value Cmid). As shown in FIG. 5A, while the output shaft gear 26 and the detection gear 27 are fixed so as not to rotate by the gear fixing mechanism 29, the steering shaft 92 is set so as to correspond to the specific value of the count value TC. Assemble to. For example, the steering wheel 91 is assembled so as to be in a neutral position with the count value TC being the median value Cmid and the gears 26 and 27 being fixed.

As shown in FIG. 5(b), when the product assembly is completed, the gear fixing mechanism 29 separates from the gears 26 and 27, thereby releasing the fixation of the gears 26 and 27. In the example of FIG. 5, the gear fixing mechanism 29 is a housing member that accommodates at least a portion of the gears 26 and 27, but the gear fixing mechanism 29 only needs to be able to fix the gears 26 and 27 so that they do not rotate, such as a pin, etc. It may be fixed at

Furthermore, when the multi-turn detection section 45 has an initialization function, the rotational position of the steering shaft 92 may be adjusted and assembled according to the count value TC after initialization. In this case, the gear fixing mechanism 29 can be omitted. The initial value x0, which is the initialized count value TC, is preferably the median value Cmid, but it may not be the median value Cmid, and may be appropriately offset depending on, for example, an assembly error. In this embodiment, the multiturn detection section 45 is physically initialized by applying a strong magnetic field, high voltage, and high current to the multiturn detection section 45. Further, the initialization process is not limited to physical initialization processing, but may be initialized using software within the count calculation unit 55, for example, so that the current position is regarded as the initial position.

By the way, as shown by the dashed line in FIG. 6, when rotation outside the original detection range of the multi-turn detection section 45 is detected, the value becomes fixed outside the detection range. In addition, if the count value TC can be changed from the minimum value Cmin or the maximum value Cmax by rotating the detection target in the opposite direction, the steering shaft 92 is rotated to the right rotation end and the left rotation end as shown by the solid line. If operated, the detection range of the multi-turn detector 45 and the operating range of the steering shaft 92 can be matched. In this case, steering midpoint learning is performed. Note that it is applicable even if the multi-turn detection section 45 is not fixed to the upper and lower limits.

The midpoint learning process of this embodiment will be explained based on the flowchart of FIG. This process is executed by the control unit 70 when learning of the median value Cmid is necessary, for example, when assembly is completed. Alternatively, this processing may be performed on the detection device 401 side. Hereinafter, the "step" in step S101 will be omitted and simply referred to as the symbol "S".

In S101, the control unit 70 calculates and stores the right end steering angle θR using the right end count value TC_R, which is the count value when the steering wheel 91 is rotated to the right rotation end.

In S102, the control unit 70 calculates and stores the left end steering angle θL using the left end count value TC_L, which is the count value when the steering wheel 91 is rotated to the left rotation end.

In S103, the control unit 70 determines whether the absolute value of the difference between the right end steering angle θR and the left end steering angle θL is greater than the operating range determination value α. The motion range determination value α is set according to the motion range between the right end and the left end of the steering wheel 91. For example, a negative determination is made when the count value TC is fixed between the right end and the left end, or when an erroneous determination is made at the end. If it is determined that the absolute value of the difference between the right-end steering angle θR and the left-end steering angle θL is less than or equal to the operating range judgment value α (S103: NO), the process returns to S101 and the right-end steering angle θR and the left-end steering angle θL are recalculated. calculate. Note that if an affirmative determination is not made even after repeated recalculations, an abnormality may be confirmed and the present process may be terminated. If it is determined that the absolute value of the difference between the right end steering angle θR and the left end steering angle θL is larger than the operating range determination value α (S103: YES), the process moves to S104, and the steering midpoint θmid is calculated and stored (formula (See (2).)

θmid=(θR+θL)/2...(2)

In this embodiment, the multi-turn detection unit 45 is configured to be able to detect magnetic changes even when no power is supplied, and continues to detect magnetic changes related to the count value TC even when no power is supplied. Then, when the IG is turned on and power is supplied to the rotation angle sensor 31, current flows to the multi-turn detection section 45 and the output is detected. It is also possible to appropriately calculate the steering angle θs. Note that the gear rotation angle θg may be determined by using the value when the starting switch is turned on, so there is no need to continue detection while the IG is turned off.

As described above, the detection device 401 includes the multi-turn detection section 45, the position detection section 40, the count calculation section 55, and the angle calculation section 50. The multi-turn detection unit 45 can continue to detect the rotational position of the steering shaft 92 driven by the motor 80 for multiple rotations without being supplied with power from the outside. The multi-turn detection unit 45 of this embodiment can continue detecting multiple rotational positions without using electric power. The position detection unit 40 detects the rotational position of the rotor 860 during one rotation. Note that the position detection section 40 has higher resolution than the multiturn detection section 45.

The count calculation unit 55 calculates multiple rotation position information regarding multiple rotation positions based on the detection value of the multiturn detection unit 45. The multiple rotation position information of this embodiment is a value related to the number of rotations of the detection gear 27, and is counted n times (n is an integer of 1 or more) during one rotation of the detection gear 27, depending on the rotation direction. This is a count value TC that is counted up or down.

The angle calculation unit 50 calculates a rotation angle θg related to the rotational position during one rotation based on the detected value of the position detection unit 40. The multi-turn detection section 45 is provided at a different location from the motor 80. Specifically, the multi-turn detection section 45 is provided in the sensor unit 4 that includes a torque sensor 421 that detects the torque input to the steering shaft 92. More specifically, the multi-turn detection section 45 is mounted on the same substrate 411 as the torque sensor 421.

Since the multi-turn detection unit 45 can continue to detect multiple rotational positions without using electric power, it can continue to detect the count value TC even if the power supply is cut off, for example after removing or replacing the battery. I can do it. Moreover, by mounting the multi-turn detection section 45 on the common board 411 with the torque sensor 421, the configuration can be simplified compared to the case where the multi-turn detection section 45 is provided separately.

The multi-turn detection unit 45 of this embodiment can magnetically hold rotational positions of multiple rotations and read out the held rotational positions by energization. Thereby, detection of rotational positions for multiple rotations can be appropriately continued without using electric power.

The multi-turn detection unit 45 detects the rotational position of the detection gear 27 that meshes with the output shaft gear 26 that rotates together with the steering shaft 92 . Thereby, multiple rotational positions of the steering shaft 92 can be appropriately detected. Furthermore, by appropriately setting the gear ratio, detection accuracy can be improved.

The detection device 401 is applied to the sensor unit 4. The sensor unit 4 is provided with a gear fixing mechanism 29 that can fix the output shaft gear 26 and the detection gear 27 when the output shaft gear 26, the detection gear 27, and the multi-turn detection section 45 are assembled to the steering shaft 92. ing. Thereby, it is possible to properly assemble the steering shaft 92 in a state where the multi-turn detection section 45 can detect multiple rotational positions of the steering shaft 92.

The multi-turn detection unit 45 can initialize detected values through initialization processing. The initialization process of this embodiment is a process of applying a strong magnetic field, high voltage, or high current. Thereby, the detected value can be properly initialized. Further, by assembling the steering shaft 92 to the steering shaft 92 according to the detected value after initialization, multiple rotational positions of the steering shaft 92 can be appropriately detected.

The count calculation unit 55 learns the reference value after operating the steering shaft 92 from one end of the operating range to the other end. In this embodiment, the median value Cmid is learned as the reference value. Thereby, multiple rotational positions of the steering shaft 92 can be appropriately detected.

The control device 1 includes a detection device 401 and a control section 70 having an absolute angle calculation section 75 that calculates an absolute angle θa, which is the amount of displacement from the reference position, based on the count value TC and the gear rotation angle θg. Since the count value TC is calculated based on the detection value of the multi-turn detection unit 45 that does not require a power source, the absolute angle θa can be appropriately calculated even when the power source is attached/detached or replaced.

(Second embodiment)
A second embodiment is shown in FIG. In this embodiment, the detection gear 27 is omitted, and the rotation angle sensor 31 detects the rotation of the multipolar magnet 15. That is, in this embodiment, the multipolar magnet 15 is commonly used for detecting torque and detecting the rotational position of the steering shaft 92.

As shown in FIG. 8, the ring portions 211 and 221 of the magnetic collecting rings 21 and 22 are formed to have a larger diameter than the magnetic yoke 16. As shown in FIG. The magnetic yoke 16 is arranged radially inside the magnetic collecting rings 21 and 22 and on the opposite side from the magnetic collecting parts 215 and 215.

In the detection device 402, the substrate 411 is placed between the magnetic flux collecting rings 21 and 22. One end of the substrate 411 is formed to extend near the magnetic yoke 16 . The torque sensor 421 is mounted on the substrate 411 at a location between the magnetic flux collectors 215 and 225. The rotation angle sensor 31 is arranged on the magnetic yoke 16 side of the substrate 411. The detected values of the torque sensor 421 and the rotation angle sensor 31 are transmitted to the ECU 10 via the communication line 408, for example, by SENT communication or the like. Further, a connector 409 is provided on the outside of the magnetic flux collecting rings 21 and 22 of the substrate 411. Note that the detection device 402 and the ECU 10 may communicate with each other via a harness (not shown) connected to the connector 409.

The angle calculation unit 50 calculates the electrical angle θe based on the detected value of the position detection unit 40. In this embodiment, one magnetic pole pair of the multipolar magnet 15 corresponds to an electrical angle of 360°. The count calculation unit 55 calculates a count value TC based on the detection value of the multiturn detection unit 45. The count value TC in this embodiment corresponds to the number of times the magnetic poles of the multipolar magnet 15 pass. Therefore, the absolute angle θa can be calculated based on the value obtained by converting the count value TC into the number of magnetic poles and the electrical angle θe. In this embodiment, since the detected value of the multipolar magnet 15 that rotates integrally with the steering shaft 92 is used, the absolute angle θa obtained by converting the number of magnetic poles matches the steering angle θs.

In this embodiment, by sharing the multipolar magnet 15, the number of parts can be reduced. Further, as shown by arrow A1, the torque sensor 421 detects the magnetic field in the axial direction of the steering shaft 92, and as shown by arrows A2 and A3, the rotation angle sensor 31 detects the magnetic flux in the circumferential direction of the multipolar magnet. Therefore, there is no disturbance on both sides and accurate detection is possible.

The torque sensor 421 detects torque by detecting changes in the magnetic flux of the multipolar magnet 15 that rotates together with the steering shaft 92. The multi-turn detection unit 45 detects the rotational position of the multi-pole magnet 15. Thereby, the number of parts can be reduced compared to the case where a magnet for detecting multiple rotational positions is separately provided. Further, the same effects as those of the above embodiment are achieved.

(Third embodiment, fourth embodiment)
The third embodiment is shown in FIG. 9, and the fourth embodiment is shown in FIG. In the embodiment described above, the substrate 411 is provided perpendicularly to the steering shaft 92. As shown in FIG. 9, in the detection device 403 of the third embodiment, the substrate 411 is provided parallel to the steering shaft 92. Here, "perpendicular" and "parallel" mean that a misalignment to the extent that the torque sensor 421 can be disposed between the magnetic flux collecting parts is allowed.

The torque sensor 421 is arranged between the magnetic flux collectors 215 and 225, and detects the strength of the magnetic field in the direction of arrow A1. Moreover, a notch may be formed in the substrate 411 to prevent interference with the magnetic flux collectors 215 and 225. The rotation angle sensor 31 is mounted on the outer side of the magnetic flux collecting rings 21 and 22 in the axial direction, and on the surface of the substrate 411 on the side facing the multipolar magnet 15. Connector 409 is provided on the opposite surface from steering shaft 92.

In the third embodiment shown in FIG. 9, surface mount type elements are used as the torque sensor 421 and the rotation angle sensor 31. In the detection device 404 of the fourth embodiment shown in FIG. 10, through-hole type elements are used as the torque sensor 422 and the rotation angle sensor 32. By using a through-hole type element, magnetism can be collected more easily. The functions of the torque sensor 422 and the rotation angle sensor 32 are the same as those of the torque sensor 421 and the rotation angle sensor 31, except that they are implemented differently. Even with this configuration, the same effects as in the above embodiment can be achieved.

(Fifth embodiment)
A fifth embodiment is shown in FIG. In the detection device 405 of this embodiment, the sensor section 425 is arranged between the magnetic flux collecting sections 215 and 225, and the functions of the torque sensor and rotation angle sensor of the above embodiment are integrated. The sensor element of the sensor section 425 is, for example, a 3D sensor, and if the radial direction of the multipolar magnet 15 is the XY direction and the axial direction is the Z direction, the rotation angle of the steering shaft 92 and the rotation angle of the steering shaft 92 can be determined by detecting the magnetic flux in the XY direction. Torque is detected by detecting the number of rotations and magnetic flux in the Z direction. Thereby, the configuration of the detection device 405 can be simplified. Further, the same effects as those of the above embodiment are achieved.

(Sixth embodiment)
A sixth embodiment is shown in FIG. In this embodiment, the absolute angle calculation unit 75 calculates the absolute angle θa based on the count value TC obtained from the rotation angle sensor 33 and the motor rotation angle θm obtained from the motor rotation angle sensor 85. In other words, in this embodiment, the count value TC and the motor rotation angle θm are values related to different rotations rather than the same rotation, so the count value TC and the motor rotation angle θm may be adjusted depending on the number of magnetic poles and gear ratio as appropriate. Convert and use in calculations. As a result, in the rotation angle sensor 33, the configuration related to the position detection section 40 and the angle calculation section 50 in the rotation angle sensor 31 is omitted. Note that in the rotation angle sensor 33, the functions of the position detection section 40 and the angle calculation section 50 related to rotation angle detection are omitted, but in this specification, it is referred to as a "rotation angle sensor."

In this case, the gear ratio of the steering shaft 92 and the motor 80 is set so that one count of the count value TC is within one revolution of the motor 80. For example, when detecting the rotation of the detection gear 27 as in the first embodiment, the gear ratio can be increased, so the detection gear 27 can be made smaller. Further, when the sensors are integrated as in the fifth embodiment, the sensor section 425 may be provided with a sensor capable of detecting the number of rotations in addition to a sensor element that detects magnetic flux in the Z direction.

The control device 1 includes a motor rotation angle sensor 85 that detects the rotation angle of the motor 80. The absolute angle calculation unit 75 calculates the absolute angle θa based on the count value TC based on the detection value of the multi-turn detection unit 45 and the motor rotation angle θm based on the detection value of the motor rotation angle sensor 85. This allows the detection and calculation of the gear rotation angle θg in the detection device 401 to be omitted, thereby simplifying the configuration. Further, the same effects as those of the above embodiment are achieved.

(Seventh embodiment)
A seventh embodiment is shown in FIGS. 13 and 14. In this embodiment, the detection device 401 of the first embodiment will be described as an example, but a detection device other than the first embodiment may be used. In addition to the motor rotation angle θm, the motor rotation angle sensor 86 calculates a count value TCm that can be converted into the number of rotations of the rotor of the motor 80. The sensor that detects the motor rotation angle θm is supplied with power when a starting switch of the vehicle, such as an ignition switch, is turned on, and the sensor that detects the count value TCm is constantly supplied with power.

The absolute angle calculating section 75 calculates the shaft side absolute angle θat and the motor side absolute angle θam. The shaft side absolute angle θat is a value calculated based on the count value TC corresponding to the number of rotations of the detection gear 27 detected by the rotation angle sensor 31 and the gear rotation angle θg. This is a rotation angle that includes information about multiple rotations from a reference position. The motor side absolute angle θam is a value calculated based on the count value TCm corresponding to the number of rotations of the motor 80 detected by the motor rotation angle sensor 85 and the motor rotation angle θm, and is a value calculated based on the motor rotation angle θm from the reference position of the motor 80. It is a rotation angle that includes multiple rotation information.

The abnormality monitoring unit 77 performs abnormality monitoring based on the absolute angles θat and θam. In terms of gear ratio, the shaft-side absolute angle θat and the motor-side absolute angle θam match if normal. Hereinafter, the absolute angles θat and θam will be explained as values after gear ratio conversion.

For example, if the wheel 98 is rotated at high speed due to an external factor, there is a risk that the connection between the steering shaft 92 and the motor 80 may become misaligned. If the steering shaft 92 and the motor 80 are connected by a belt, there will be belt skipping, and if they are connected by gears, there will be tooth skipping, which will be described below as "belt jumping."

Furthermore, if the count value TCm is reset due to power failure due to battery replacement or the like, there is a possibility that the motor side absolute angle θam becomes a value different from the shaft side absolute angle θat. Since such belt skipping and power supply failure are not abnormalities in electronic components such as sensors, it is desirable to isolate them from other abnormalities and restore normality.

The abnormality detection process of this embodiment will be explained based on the flowchart of FIG. 14. This process is executed by the control unit 70, for example, when the IG is turned on. In S201, the absolute angle calculation unit 75 calculates the shaft side absolute angle θat based on the count value TC of the rotation angle sensor 31 and the gear rotation angle θg, and calculates the shaft side absolute angle θat based on the count value TCm of the motor rotation angle sensor 86 and the motor rotation angle θm. Based on this, the motor side absolute angle θam is calculated.

In S202, the abnormality monitoring unit 77 determines whether the absolute value of the difference between the shaft side absolute angle θat and the motor side absolute angle θam is smaller than the abnormality determination value β. The abnormality determination value β is set according to an allowable value as the difference between the shaft side absolute angle θat and the motor side absolute angle θam. If it is determined that the absolute value of the difference between the absolute angles θat and θam is smaller than the abnormality determination value β (S202: YES), the process moves to S203, and it is determined that the absolute angles θat and θam are normal. If it is determined that the absolute value of the difference between the absolute angles θat and θam is greater than or equal to the abnormality determination value β (S202: NO), the process moves to S204.

In S204, the abnormality monitoring unit 77 determines whether there is an abnormality history in at least one of the detection device 401 and the ECU 10. If it is determined that there is no abnormality history in the detection device 401 and the ECU 10 (S204: NO), the process moves to S205 and it is determined that the belt has jumped. If it is determined that the detection device 401 or the ECU 10 has an abnormality history (S204: YES), the process moves to S206.

In S206, the abnormality monitoring unit 77 determines whether there is a history of power failure. For example, when the battery is replaced, the power supply to the motor rotation angle sensor 85 is interrupted, so a power failure abnormality is stored. Further, a power failure abnormality may be detected by setting a specific flag at the time of startup accompanied by power-on. If it is determined that there is a power failure history (S206: YES), the process moves to S207, and it is determined that a power failure has occurred. If it is determined that there is no power failure history (S206: NO), the process moves to S209.

In S208, which is the next step after it is determined that the belt has skipped (S205) or that the power supply has failed (S207), the control unit 70 determines whether the shaft side absolute angle θat and the motor side absolute angle θam are The motor side absolute angle θam is corrected so that they match. In S209, it is determined that the absolute angles θat and θam are abnormal, and the process moves to a backup operation.

In this embodiment, since the absolute angles θat and θam are calculated using different configurations, abnormalities can be appropriately detected. Moreover, the same failure mode can be avoided. Further, by using the shaft side absolute angle θat and the motor side absolute angle θam, belt skipping can be appropriately detected.

The absolute angle calculation unit 75 calculates a shaft side absolute angle θat calculated based on the detection value of the multi-turn detection unit 45 and the detection value of the position detection unit 40 that detects the rotational position of the steering shaft 92 during one rotation, and A motor-side absolute angle θam is calculated based on the detected value of the motor rotation angle sensor 85. The control unit 70 includes an abnormality monitoring unit 77 that performs abnormality monitoring based on the shaft-side absolute angle θat and the motor-side absolute angle θam. This makes it possible to appropriately detect power failures, belt jumps, and the like. Further, the same effects as those of the above embodiment are achieved.

(Eighth embodiment)
The eighth embodiment is shown in FIGS. 15 and 16. As shown in FIG. 15, the rotation angle sensor 34 includes a main detection section 41, a sub-detection section 42, a multi-turn detection section 45, angle calculation sections 51 and 52, count calculation sections 55 and 56, a torque sensor 421, and a communication section. 58 and 59, and power is supplied from power sources 391 and 392. In the following embodiments, illustrations of the motor rotation angle sensor 85 and the torque sensor 421 are omitted as appropriate. The power supply 391 is capable of supplying power to the rotation angle sensor 34 via the IG when the IG is turned on, and the power supply 392 is a constant voltage power supply such as a regulator, and is not shown in the figure, regardless of the on/off state of the IG. Power can be supplied to the rotation angle sensor 34 from the battery. In the figure, blocks surrounded by dashed lines are constantly supplied with power.

Like the position detection unit 40, the main detection unit 41 and the sub detection unit 42 detect the rotation of the detection gear 27 that meshes with the output shaft gear 26 that rotates together with the output shaft 12. Furthermore, the main detection section 41 and the sub-detection section 42 may be configured to detect the rotation of the multipolar magnet 15, as in the second embodiment. The same applies to the embodiments described below.

It is desirable that the main detection section 41 and the sub-detection section 42 have different sensor characteristics. For example, the main detection section 41 is an AMR element, and the sub-detection section 42 is a TMR element. Here, even if the types of elements are the same, differences in layout, material ratio, manufacturing lot, wafer number within the lot, and chip position within the wafer may be considered to be "different configurations related to the detection element." Furthermore, not only the elements but also the detection circuits and arithmetic circuits connected to the elements, and the types and voltages of the supplied power sources may also be considered to be different as "the configurations related to the detection elements are different." By using sensors with different characteristics, failures due to common causes such as magnetic flux density abnormalities are less likely to occur, which is preferable from the viewpoint of functional safety. For the sub-detection section 42, a TMR element is preferably used when low power consumption is important, and an AMR element is preferably used when emphasis is placed on magnetic field resistance.

Here, the reason why the detection units 41 and 42 are labeled as “main” and “sub” is to distinguish between the two, and they may be functionally equivalent. Further, the functions may be divided, for example, the main detection section 41 is used for control, and the sub-detection section 42 is used for abnormality monitoring. The same applies to the embodiments described below. Hereinafter, the configurations and values related to the main detection section 41 will be denoted with "A," and the configurations and values related to the sub-detection section 42 will be denoted with "B."

The angle calculation unit 51 calculates the gear rotation angle θg_A based on the detection value of the main detection unit 41 that has been AD converted by an AD conversion unit (not shown). The angle calculation section 52 calculates the gear rotation angle θg_B based on the detection value of the sub-detection section 42 that has been AD-converted by an AD conversion section (not shown). Hereinafter, when the values calculated by the angle calculation units 51 and 52 are to be distinguished, they will be referred to as gear rotation angles θg_A and θg_B, and when there is no need to differentiate, they will be simply referred to as gear rotation angle θg. By comparing gear rotation angles θg_A and θg_B, it is possible to detect whether an abnormality has occurred.

The count calculation section 56 is constantly supplied with power from the power source 392 and calculates the count value TC of the detection gear 27 based on the detection value of the sub-detection section 42 . Hereinafter, when distinguishing between the value calculated by the count calculation unit 55 and the value calculated by the count calculation unit 56, the value calculated by the count calculation unit 55 is used as the count value NPTC (No Power Turn Count), and the count calculation unit 56 The value calculated by the unit 56 is defined as LPTC (Low Power Turn Count). The count values NPTC and LPTC are calculated using detected values of different detection methods, and have a heterogeneous redundant configuration. In addition, the count value NPTC is counted by 1 for one rotation of the detection gear 27, the count value LPTC is counted by 4 for one rotation of the detection gear 27, and so on, the count value NPTC and the count value LPTC are The number of counts per revolution may be different. For example, when comparing count values NPTC and LPTC, appropriate conversion may be performed. Hereinafter, if it is not necessary to distinguish between the detection units, the count value will simply be referred to as TC.

By comparing the count values NPTC and LPTC, it is possible to detect whether or not an abnormality has occurred. Further, the comparison of the count values may be performed within the rotation angle sensor 34 or may be performed by the control unit 70. The same applies to gear rotation angles θg_A and θg_B. Furthermore, the same effect can be obtained even if the absolute angles θa_A and θa_B are calculated and then compared. The communication unit 58 outputs the gear rotation angle θg_A and the count value NPTC to the control unit 70, and the communication unit 59 outputs the gear rotation angle θg_B and the count value LPTC to the control unit 70.

Although the multi-turn detection unit 45 has the advantage of not requiring power supply, there is a risk of deviation in the corresponding rotation speed, disturbance magnetic field, data loss due to long-term data retention, and the like. Therefore, in this embodiment, in addition to calculating the count value NPTC using the detection value of the multi-turn detection section 45, power is constantly supplied to the sub-detection section 42 and the count calculation section 56 to calculate the count value LPTC. This makes the calculation of the count value TC redundant and allows detection of abnormalities. Furthermore, by having the multi-turn detector 45 and the sub-detector 42 in different configurations, common cause failures are less likely to occur and abnormalities can be easily detected.

Absolute angle calculation section 75 calculates absolute angle θa_A based on gear rotation angle θg_A and count value NPTC, and calculates absolute angle θa_B based on gear rotation angle θg_B and count value LPTC. The abnormality monitoring unit 77 performs abnormality monitoring based on the absolute angles θa_A and θa_B.

The abnormality monitoring process of this embodiment will be explained based on the flowchart of FIG. 16. This process is executed by the control unit 70. Here, if the count value TC is used in the initial calculation at startup and is not used during operation, it is executed when the IG is switched from off to on or when the control unit 70 is reset. . When the count value TC is used not only for the initial calculation at startup but also continuously during operation, it is executed at a predetermined cycle even during operation. Hereinafter, the "step" in step S101 will be omitted and simply referred to as the symbol "S".

In S301, the control unit 70 obtains gear rotation angles θg_A, θg_B, and count values NPTC and LPTC. In S302, the control unit 70 calculates the absolute angle θa_A using the count value NPTC and the gear rotation angle θg_A, and calculates the absolute angle θa_B using the count value LPTC and the gear rotation angle θg_B (see equation (1)). .

In S303, the control unit 70 performs abnormality determination by comparing the absolute angles θa_A and θa_B. If there are two values calculated in S302, if the difference is within the normal range, it is determined to be normal, and if the difference is outside the normal range, it is determined to be abnormal. Further, for example, if there are three or more detection units and three or more absolute angles θa can be calculated, a normal value is specified by majority vote. The gear rotation angle θg and the count value TC used to calculate the normal absolute angle θa are defined as "normal signals."

In S304, the control unit 70 determines whether there is a normal absolute angle θa. If it is determined that there is a normal absolute angle θa (S304: YES), the process moves to S305, and various control calculations such as calculation of the steering angle θs are performed using any normal signal or the aggregate value of multiple normal signals. I do. If it is determined that there is no normal absolute angle θa (S304: NO), the process moves to S306 and the absolute angle θa is reset. In this case, since the correspondence relationship between the absolute angle θa and the steering angle θs is uncertain, for example, by detecting the absolute angle θa when the vehicle is traveling straight when the steering wheel 91 is in the neutral position, the absolute angle θa and the steering angle θs can be Learn correspondence. Furthermore, depending on the system, detection of the absolute angle θa may be stopped.

The rotation angle sensor 34 includes a count calculation unit 56 that calculates a count value TC based on the detection value of the sub-detection unit 42. The sub-detection section 42 and the count calculation section 56, whose detected values are used to calculate the count value TC, are constantly supplied with power. Thereby, even if a disturbance magnetic field abnormality or the like occurs in the multi-turn detection unit 45, it is possible to continue detecting the count value TC. Further, by comparing the count values NPTC and LPTC, abnormality can be detected. Furthermore, since the detection principles of the detected values used to calculate the count values NPTC and LPTC are different, it is possible to reduce the probability of occurrence of a failure due to a common cause.

In this embodiment, a main detection section 41 and a sub-detection section 42 are provided as position detection sections. In other words, there are a plurality of position detection units in this embodiment. The detection value of the sub-detection section 42, which is at least one position detection section, is shared by the angle calculation section 52 and the count calculation section 56. This makes it possible to make the calculations of the gear rotation angle θg and the count value TC redundant with a relatively simple configuration.

The main detection section 41 and the sub-detection section 42 have different configurations related to detection elements. This makes it possible to suppress the occurrence of abnormalities due to the same cause, thereby improving functional safety. "Element-related configurations" are those in which the types of elements are different (e.g., TMR elements, AMR elements, Hall elements, etc.), the internal configurations of the elements are different (e.g., different wafers, different layouts, materials used, etc.). (different manufacturing conditions, different manufacturing lots, etc.), different circuit configurations connected to the elements, or different types and voltages of power supplies supplied to the elements.

At least two absolute angles θa_A and θa_B are calculated using different count values NPTC and LPTC and motor rotation angles θm_A and θm_B. The control unit 70 includes an abnormality monitoring unit 77 that performs abnormality monitoring based on a plurality of absolute angles θa_A and θa_B calculated using different detected values. Thereby, abnormality monitoring of the rotation angle sensor 34 can be appropriately performed. Further, the same effects as those of the above embodiment are achieved.

(9th embodiment, 10th embodiment)
The ninth embodiment is shown in FIGS. 17 and 18, and the tenth embodiment is shown in FIG. 19. As shown in FIGS. 17 and 19, the control unit 70 of this embodiment can acquire an external detection value that can be converted into an absolute angle θa from the external sensor 500. As the rotation angle sensor, FIG. 17 of the ninth embodiment shows the rotation angle sensor 34 of the eighth embodiment, and FIG. 19 of the tenth embodiment shows the rotation angle sensor 31 of the first embodiment. Communication between the external sensor 500 and the control unit 70 may be performed using any communication method such as CAN (Controller Area Network), LIN (Local Interconnect Network), or Flexray. The external sensor 500 is, for example, a steering sensor, a stroke sensor, or the like. The absolute angle θa_C is a value converted from the detected value of the external sensor 500 using the gear ratio of the gear connecting the motor 80 and the steering system, etc. so that it can be compared with the absolute angles θa_A and θa_B.

Abnormality monitoring will be described below, focusing on the ninth embodiment. In the ninth embodiment, three values can be used as the absolute angle θa, so in S303 in FIG. 16, a value that is different from the other two values is identified as abnormal. In FIG. 18, comparison (1) is a comparison of absolute angles θa_A and θa_B, comparison (2) is a comparison of absolute angles θa_A and θa_C, and comparison (3) is a comparison of absolute angles θa_B and θa_C. If comparisons (1), (2), and (3) are all normal, it is determined that absolute angles θa_A, θa_B, and θa_C are all normal, and comparisons (1), (2), and (3) are abnormal. In this case, normal values and abnormal values cannot be identified. Also, if two of the comparisons (1), (2), and (3) are normal and one is abnormal, it is also impossible to specify.

If comparisons (1) and (2) are abnormal and comparison (3) is normal, the absolute angle θa_A is identified as abnormal. Cases in which the absolute angle θa_A becomes abnormal include cases in which a failure occurs that makes it impossible to continue detection, and cases in which data in the multiturn detection unit 45 is skipped due to a disturbance magnetic field.

If comparisons (1) and (3) are abnormal and comparison (2) is normal, the absolute angle θa_B is identified as abnormal. Cases in which the absolute angle θa_B becomes abnormal include cases in which a failure occurs in the sub-detection unit 42 that makes it impossible to continue detection, and cases in which a power failure occurs due to battery replacement or the like.

If comparisons (2) and (3) are abnormal and comparison (1) is normal, the absolute angle θa_C is identified as abnormal. The case where the absolute angle θa_C becomes abnormal includes a case where the external sensor 500 has a failure that makes it unable to continue detection.

In other words, even if the absolute angles θa_A, θa_B, and θa_C are abnormal, this includes a case where it is not a failure but a data abnormality. Therefore, the internal monitoring function of each sensor and the external monitoring function are used to separately determine whether or not there is a failure. If it is determined that there is no failure, correction processing is performed according to the difference from the sensor that has been determined to be normal. You can.

In addition, the sensor configuration is such that multiple calculations can be made for each of the absolute angles θa_A, θa_B, and θa_C. For example, if both the absolute angles θa_Ax and θa_Ay corresponding to the absolute angle θa_A are identified as abnormal, it is possible to continue detection by correction rather than a failure. It may be determined that the data is abnormal, and if one of the absolute angles θa_Ax and θa_Ay is abnormal, it may be determined that there is a failure.

The control unit 70 acquires an external detection value that can be converted into an absolute angle θa from the external sensor 500, and calculates an absolute angle θa_C calculated from the detection value of the external sensor 500 and an absolute angle θa_A based on the detection value of the rotation angle sensor 34. , θa_B. That is, the absolute angles θa_A, θa_B, and θa_C are "a plurality of absolute positions calculated using different detected values." Thereby, abnormality monitoring can be appropriately performed using the detected value of the external sensor 500. Further, if at least one of the absolute angle based on the detected value of the rotation angle sensor 34 and the detected value of the external sensor 500 is plural, and a total of three or more absolute angles can be used, the abnormal location is determined by majority vote. Identifiable. Further, the same effects as those of the above embodiment are achieved.

(Eleventh embodiment)
The eleventh embodiment is shown in FIG. The ECU 79 of this embodiment includes drive circuits 120, 220, control units 170, 270, motor rotation angle sensors 185, 285, and the like. In this embodiment, since two control units 170 and 270 are provided, drive control of the motor 80 can be continued even if one of the control units fails.

The first control section 170 includes an absolute angle calculation section 175, a control calculation section 176, and an abnormality monitoring section 177. The second control section 270 includes an absolute angle calculation section 275, a control calculation section 276, and an abnormality monitoring section 277. The absolute angle calculation units 175 and 275 calculate the steering angle θs in addition to the absolute angle θa.

The control calculation unit 176 controls the energization of the motor winding 180 by controlling the on/off operation of the first switching element that constitutes the first drive circuit 120 . The control calculation unit 276 controls the energization of the motor winding 280 by controlling the on/off operation of the second switching element that constitutes the second drive circuit 220 . The abnormality monitoring units 177 and 277 perform abnormality monitoring by mutual monitoring of absolute angles. The control units 170 and 270 are capable of transmitting and receiving information through communication. Hereinafter, communication between the control units 170 and 270 will be referred to as inter-microcomputer communication.

The first rotation angle sensor 133 includes a main detection section 141 , a sub-detection section 142 , a multi-turn detection section 145 , angle calculation sections 151 and 152 , a count calculation section 155 , and a communication section 158 . The second rotation angle sensor 233 includes a main detection section 241 , a sub-detection section 242 , a multi-turn detection section 245 , angle calculation sections 251 and 252 , a count calculation section 255 , and a communication section 258 . The first rotation angle sensor 133 is supplied with power from the power supply 191 when the IG is on, and the second rotation angle sensor 233 is supplied with power from the power supply 291 when the IG is on. . The power supplies 191 and 291 are constant voltage power supplies such as regulators, like the power supply 391 in the above embodiment.

The main detection units 141 and 241 are the same as the main detection unit 41 of the eighth embodiment, the sub detection units 142 and 242 are the same as the sub detection unit 42 of the eighth embodiment, and the angle calculation units 151 and 251 are the same as the main detection unit 41 of the eighth embodiment. It is the same as the calculation section 51, and the angle calculation sections 152 and 252 are the same as the angle calculation section 52. Below, the configuration and values related to the main detection unit 141 will be “A1”, the configuration and values related to the sub detection unit 142 will be “B1”, the configuration and values related to the main detection unit 241 will be “A2”, and the sub detection unit 242 will be “A1”, "B2" is attached to such configurations and values. Further, the multiturn detection sections 145 and 245 are similar to the multiturn detection section 45, and the count calculation sections 155 and 255 are similar to the count calculation section 55.

Here, the value calculated by the angle calculation unit 151 is the gear rotation angle θg_A1, the value calculated by the angle calculation unit 152 is the gear rotation angle θg_B1, and the value calculated by the angle calculation unit 251 is the gear rotation angle θg_A2. , the value calculated by the angle calculation unit 252 is defined as gear rotation angle θg_B2. Further, the value calculated by the count calculation unit 155 is assumed to be a count value NPTC1, and the value calculated by the count calculation unit 255 is assumed to be a count value NPTC2.

The communication unit 158 transmits the gear rotation angles θg_A1, θg_B1 and the count value NPTC1 to the first control unit 170. The communication unit 258 transmits the gear rotation angles θg_A2, θg_B2 and the count value NPTC2 to the second control unit 270.

In this embodiment, the first rotation angle sensor 133 and the first control section 170 are included in the first system, and the second rotation angle sensor 233 and the second control section 270 are included in the second system. Furthermore, in each system, one count value NPTC is calculated and two gear rotation angles θg are calculated. In this embodiment, since the rotation angle sensors 133, 233 and the control units 170, 270 are configured in the same way in the first system and the second system, the processing in the first control unit 170 will be mainly explained. As for the processing in the second control unit 270, the values used for calculations can be read as the values of the own system, so the description will be omitted as appropriate.

The first control unit 170 calculates the steering angle θs using the count value NPTC1 in the first calculation when the IG is switched from off to on, and after the first calculation, integrates the amount of change in the gear rotation angle θg to the first calculation value. By doing so, the steering angle θs is calculated. This eliminates the need to constantly monitor the count value NPTC. Before the first calculation after turning on the IG, the count value NPTC1 performs self-monitoring within the system as described in the third embodiment, or abnormality monitoring by comparing it with the count value NPTC2 acquired through communication between microcomputers. .

Further, the gear rotation angle θg is configured to be able to calculate two values for each system, and is constantly monitored at a predetermined period while the IG is on by comparison within the system. This makes it possible to reduce the load on inter-microcomputer communication compared to the case where abnormality monitoring is performed by acquiring gear rotation angles through inter-microcomputer communication from other systems. Further, since abnormality monitoring within the system is possible, the absolute angle θa can be calculated at high speed using the value determined to be normal. With this configuration, constant power supply is not required and abnormality monitoring can be performed appropriately. Further, the same effects as those of the above embodiment are achieved.

(12th embodiment)
A twelfth embodiment is shown in FIG. 21. The second rotation angle sensor 234 includes a main detection section 241, a sub-detection section 242, angle calculation sections 251 and 252, a count calculation section 256, and a communication section 258, and is supplied with power from power supplies 291 and 292. The power source 291, like the power source 391, can be supplied with power via the IG when the IG is turned on, and the power source 292, like the power source 392, can be constantly supplied with power from the battery regardless of the on/off state of the IG.

In this embodiment, the multi-turn detection section is omitted in the second rotation angle sensor 234, and the count calculation section 256 calculates the count value LPTC2 using the detection value of the sub-detection section 242. The count calculation unit 256 is similar to the count calculation unit 56. The communication unit 258 transmits the gear rotation angles θg_A2, θg_B2 and the count value LPTC2 to the second control unit 270. Further, the first control unit 170 can acquire the detection value of the external sensor 500.

In this embodiment, the absolute angle θa_A1 is calculated using the count value NPTC in the first system L1, the absolute angle θa_B2 is calculated using the count value LPTC in the second system L2, and the detection of the external sensor 500 Three values of the absolute angle θa_C based on the value are used. The absolute angles θa_A1, θa_B2, and θa_C are shared by the control units 170 and 270 through inter-microcomputer communication.

The details of the abnormality monitoring are substantially the same as those in the ninth embodiment, and in normal times, three values of absolute angles θa_A1, θa_B2, and θa_C are compared. When a power failure occurs due to a dead battery or battery replacement, abnormality monitoring is performed by comparing the absolute angles θa_A1 and θa_C. If the count value NPTC becomes abnormal due to disturbance such as a strong magnetic field, the absolute angles θa_B2 and θa_C are monitored. Perform abnormality monitoring by comparison.

In this embodiment, since three values of the absolute angles θa_A1, θa_B2, and θa_C can be used, abnormalities caused by power failure or disturbance can be appropriately detected. Further, by comparing the absolute angle θa_C based on the detected value of the external sensor 500, abnormality detection is performed by comparing the steering system side rather than the connection part with the gear as a countermeasure when the drive device 400 is removed from the steering system. It can be carried out. Further, the same effects as those of the above embodiment are achieved.

(13th embodiment)
A seventh embodiment is shown in FIG. 22. In addition to the configuration of the first rotation angle sensor 133 of the fourth embodiment, the first rotation angle sensor 135 has a count calculation unit 156, and is supplied with power from the power source 191 when the IG is on, and is in the on/off state of the IG. Power is always supplied from the power supply 192 regardless of the time. The count calculation section 156 calculates the count value LPTC1 using the detection value of the sub-detection section 142. The communication unit 158 transmits the gear rotation angles θg_A1 and θg_B1 and the count values NPTC1 and LPTC1 to the first control unit 170.

In addition to the configuration of the second rotation angle sensor 233 of the tenth embodiment, the second rotation angle sensor 235 has a count calculation unit 256, and is supplied with power from the power supply 291 when the IG is on, and is in the on/off state of the IG. Power is always supplied from the power source 292 regardless of the power source. The communication unit 258 transmits the gear rotation angles θg_A2 and θg_B2 and the count values NPTC2 and LPTC2 to the second control unit 270. Although the second rotation angle sensor 235 has one multi-turn detection section 245, a more robust system can be constructed by making the multi-turn detection section 245 redundant. The same applies to the first rotation angle sensor 135.

The control units 170 and 270 can obtain external detection values that can be converted into absolute angles from the two external sensors 500 and 501. The external sensors 500 and 501 may be, for example, a steering sensor, a stroke sensor, etc., and may be of the same type or of different types. Also in the ninth embodiment and the tenth embodiment, external detection values may be acquired from a plurality of external sensors.

In this embodiment, two gear rotation angles θg, count values NPTC, LPTC, and external detection values from two external sensors 500 and 501 can be used in each system, and one system is based on majority vote. It is possible to identify abnormalities. Furthermore, control using normal detected values can be continued. In addition, even if one of the rotation angle sensors 135, 235 is out of order, the detected value of the normal rotation angle sensor is shared between the control units 170, 270 through communication between microcomputers, so that the two systems can be operated. Motor control can be continued. Further, the same effects as those of the above embodiment are achieved.

In the embodiment, the steering shaft 92 is a "detection target", the output shaft gear 26 is a "detection target gear", the multipolar magnet 15 is a "magnet", the count calculation units 55, 155, and 255 are "multiple rotation position calculation units", The absolute angle calculation sections 75, 175, and 275 correspond to the "absolute position calculation section." In addition, the count value TC is "multiple rotation position information", the gear rotation angle θg and the motor rotation angle θm are "rotation angle information", the shaft side absolute angle θat is "detection target side absolute position", and the motor side absolute angle θam is " Corresponds to "motor side absolute position".

(Other embodiments)
In the above embodiment, the multi-turn detection section magnetically holds rotational positions of multiple rotations. In other embodiments, the multi-turn detection unit may use means other than magnetism as long as it can continue detecting multiple rotational positions without using electric power. For example, the detection gear 27 may be made larger than the output shaft gear 26. good. Even with this configuration, multiple rotational positions can be detected without using electric power. Furthermore, the number of parts can be reduced compared to a normal steering sensor.

In addition, "the detection of multiple rotational positions of the detection target can be continued without an external power supply" is not limited to detection without power using magnetism, etc. as in the above embodiment, but in a broad sense, it means a sensor. By providing an internal battery inside, detection of rotational positions for multiple rotations may be continued without power supply from the outside. In another embodiment, when the count value TC reaches the maximum value Cmax, the next count up is set to the minimum value Cmin, and when the count value TC reaches the minimum value Cmin, the next countdown is set to the maximum value Cmax. TC may be looped.

In the above embodiment, the control device is used in an electric power steering device. In other embodiments, the controller may be used in a steer-by-wire system. Further, in the above embodiment, the multi-turn detection section is provided in the torque sensor unit. In other embodiments, the multi-turn detection section may be provided at a location other than the torque sensor unit. For example, when torque detection is not required, such as in a steer-by-wire system, the detection gear may be placed at any possible location, such as a rack gear or the steering wheel side of a steering shaft.

Furthermore, the control device can be suitably applied to applications other than steer-by-wire systems that require the number of rotations and rotation angle. Furthermore, if the stroke position is converted into a rotation system using a gear, it can also be applied to a stroke sensor.

In the third embodiment, a steering sensor and a stroke sensor are exemplified as external sensors. In other embodiments, an analysis value of a laser displacement meter or a camera image may be used as the external sensor.

In the embodiment described above, communication between the control units is performed by inter-microcomputer communication. In other embodiments, instead of communication between microcomputers, communication between control units may be performed via a vehicle communication network such as CAN.

In the above embodiment, one sensor section is provided with one multiturn detection section and one or two position detection sections. In other embodiments, one sensor section may be provided with two or more multiturn sensors, or may be provided with three or more position detection sections.

In the above embodiment, one control section is provided for one sensor section, and the number of systems is one or two. In other embodiments, the number of systems may be three or more. Furthermore, one control section may be provided for a plurality of sensor sections, or one sensor section may be provided for a plurality of control sections.

In the above embodiments, the motor is a three-phase brushless motor. In other embodiments, the motor may be any motor, not just a three-phase brushless motor. Further, the motor is not limited to an electric motor, and may be a generator, or a so-called motor generator that has both the functions of an electric motor and a generator. In the above embodiment, there are two systems of inverter and motor windings. In other embodiments, the number of inverter and motor winding systems may be one or three or more. Also, the numbers of inverters and motor windings may be different. In the above embodiment, the control device is applied to an electric power steering device. In other embodiments, the control device may be applied to devices other than electric power steering devices.

The control unit and the method described in the present disclosure are implemented by a dedicated computer provided by configuring a processor and memory programmed to perform one or more functions embodied by a computer program. may be done. Alternatively, the controller and techniques described in this disclosure may be implemented by a dedicated computer provided by a processor configured with one or more dedicated hardware logic circuits. Alternatively, the control unit and the method described in the present disclosure may be implemented using a combination of a processor and memory programmed to perform one or more functions and a processor configured by one or more hardware logic circuits. It may be implemented by one or more dedicated computers configured. The computer program may also be stored as instructions executed by a computer on a computer-readable non-transitory tangible storage medium. As described above, the present invention is not limited to the above-described embodiments, and can be implemented in various forms without departing from the spirit of the invention.

1... Control device 40... Position detection section 41, 141, 241... Main detection section (position detection section)
42, 142, 242...Sub detection section (position detection section)
45, 145, 245...Multi-turn detection unit 50-52, 151, 152, 251, 252...Angle calculation unit 55, 155, 255...Count calculation unit (multiple rotation position calculation unit)
80...Motor 85...Motor rotation angle sensor (position detection section)
92... Steering shaft (detection target)
401-405...detection device

Claims (8)

A multi-turn detection unit (45, 145, 245) capable of continuously detecting the rotational position of a detection target (92) driven by a motor (80) during multiple rotations without an external power supply; a position detection section (40, 41, 42, 141, 142, 241, 242, 85 ) that detects the rotational position of the multi-turn detection section; A multi-rotation position calculation unit (55, 155, 255) that calculates information , and an angle calculation unit (50 to 52) that calculates rotation angle information regarding the rotation position during one rotation based on the detected value of the position detection unit. , 151, 152 , 251, 252);
a control unit (70) that controls driving of the motor;
a motor rotation angle sensor (85) that detects the rotation angle of the motor;
Equipped with
The multi-turn detection section is provided at a location different from the motor ,
The detection device or the control unit includes an absolute position calculation unit (75) that calculates an absolute position that is a displacement amount of the detection target from a reference position based on the multiple rotation position information and the rotation angle information,
The absolute position calculation unit calculates, as the absolute position, a detection target side absolute position calculated based on the detection values of the multi-turn detection unit and the position detection unit, and a detection value of the motor rotation angle sensor. Calculate the motor side absolute position to be calculated,
The control unit includes an abnormality monitoring unit (77) that performs abnormality monitoring based on the detection target side absolute position and the motor side absolute position,
The abnormality monitoring unit detects the detection target and the A control device that determines that there is a misalignment in the connection between the motor and the motor . The control device according to claim 1, wherein the multiple rotation position information is a count value that is counted up or down n times (n is an integer of 1 or more) during one rotation of the detection target depending on the rotation direction. The control device according to claim 1 or 2, wherein the multi-turn detection section magnetically holds rotational positions of multiple rotations and is capable of reading out the rotational positions held by energization. The control device according to any one of claims 1 to 3, wherein the detection device includes a torque sensor (421) that detects torque input to the detection target. The control device according to any one of claims 1 to 4, wherein the multi-turn detection section detects a rotational position of a detection gear (27) that meshes with a detection target gear (26) that rotates together with the detection target. . The torque sensor detects torque by detecting a change in magnetic flux of a magnet (15) that rotates together with the detection target,
The control device according to claim 4, wherein the multi-turn detection section detects a rotational position of the magnet. The control device according to any one of claims 1 to 6 , wherein the multi-turn detection section is capable of initializing the detected value through initialization processing. The control device according to any one of claims 1 to 7 , wherein the multiple rotation position calculation unit learns a reference value after operating the detection target from one end to the other end of the motion range. .

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