JPH06178586A - Abnormality detection device for brushless motor - Google Patents

Abstract

(57) [Summary] [Purpose] In a brushless motor, to detect an abnormality according to the transition of the signal state. In a brushless motor including a magnetic pole sensor that detects rotation of a motor shaft and a phase switching control unit 62 that switches and outputs a phase switching pattern according to a change in output of the rotation sensor, the phase switching control unit includes a phase switching pattern. After switching and outputting L1, the magnetic pole sensor for judging an abnormality when the actual output signal of the magnetic pole sensor is different from the expected signal of the rotation sensor expected when the brushless motor rotates to the right or to the left. The abnormality determination unit 63 is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting abnormality of a brushless motor.

[0002]

2. Description of the Related Art Conventionally, a device for detecting an abnormality of a brushless motor by detecting a position has been developed. For example,
In the technique disclosed in Japanese Unexamined Patent Publication No. 64-74089, the output of the driver is prohibited when the combination of signals obtained from the three-phase position detector is an impossible combination.

[0003]

However, in the above technique, there is a combination in which even if one of the position detectors has an abnormality, it is not judged as an abnormality. In this case, if a signal for rotating the motor for one cycle is sent, the abnormality can be determined in any one of them, but there is a possibility that the abnormality cannot be detected when the motor is controlled in a minute range. Although any abnormality can be detected eventually, there is a problem when the detection timing is delayed and urgent abnormality avoidance is required. In addition, even if a plurality of position detecting means fail at the same time, there is a possibility that the abnormality cannot be detected.

Therefore, it is an object of the present invention to be able to detect an abnormality in accordance with the transition of the signal state.

[0005]

In order to solve the above-mentioned problems, in the invention of claim 1, a motor shaft, a rotation sensor for detecting the rotation of the motor shaft, and an output change of the rotation sensor In a brushless motor provided with a phase switching control means for switching and outputting a phase switching pattern, it is expected when the brushless motor rotates right or left after the phase switching control means switches and outputs the phase switching pattern. An abnormality determining means is provided for determining an abnormality when the actual output signal of the rotation sensor is different from the expected signal of the rotation sensor.

[0006]

According to the first aspect of the present invention, if the brushless motor is normal, it is expected that the brushless motor rotates to the right or to the left after the phase switching control means switches and outputs the phase switching pattern. The actual output signal of the rotation sensor matches any of the expected signals of the rotation sensor. However, if the motor shaft does not rotate despite switching the output, the actual output signal of the rotation sensor differs from the expected signal of the rotation sensor expected when the brushless motor rotates to the right or left. Come on. If the rotation sensor is a linear sensor, the output does not change when the rotation sensor fails, so that the failure can be detected immediately. In addition, in the rotation sensor of the type that the rotation sensor is composed of multiple Hall elements and magnetoresistive elements, etc. and detects the rotation from the combination of the outputs of multiple elements, a failure is detected when the output of each element changes. it can.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the abnormality detecting device for a brushless motor of the present invention is mounted on a rear wheel steering device will be described below with reference to the drawings.

FIG. 1 shows the structure of a vehicle equipped with the rear wheel steering system of the present invention. The front wheels 13 and 14 are steered by the front wheel steering device 10 in accordance with the turning operation of the steering wheel 19. The steering amount of the front wheels is detected by a first front wheel steering angle sensor 17 that detects a movement amount of a rack of the front wheel steering device 10 and a second front wheel steering angle sensor 20 that is provided on a steering shaft to which a steering wheel 19 is attached. . The first front wheel steering angle sensor 17 uses a linear sensor such as a potentiometer, and the second front wheel steering angle sensor 20 uses a steering sensor such as a rotary encoder that emits a pulse during rotation.

The rear wheels 15 and 16 are steered by the rear wheel steering mechanism 11. The rear wheel steering mechanism 11 operates according to the rotation of the motor 12. A magnetic pole sensor 18 for detecting the rotation angle of the motor 12 is provided at the end of the motor 12. Further, a rear wheel steering angle sensor 21 for detecting the actual steering angle of the rear wheels 15 and 16 is provided on a rack shaft 25 as a rear wheel steering shaft. The rear wheel steering angle sensor 21 may be built in the rear wheel steering mechanism 11.

The vehicle also detects the speed of the vehicle.
The system includes a first vehicle speed sensor 22, a second vehicle speed sensor 23, and a yaw rate sensor 24 that measures the yaw rate of the vehicle.

The motor 12 is controlled by a signal from the electronic control unit 9. The electronic control unit 9 includes a first front wheel steering angle sensor 17, a second front wheel steering angle sensor 20, a magnetic pole sensor 18, a rear wheel steering angle sensor 21, a first vehicle speed sensor 22, a second vehicle speed sensor 23, and a yaw rate sensor 24. Receiving sensor output,
The amount of rotation of the motor 12 is determined and a control signal is sent to the motor 12 for control.

The rear wheel steering mechanism 11 is shown in FIG. Here, an example in which the rear wheel steering angle sensor 21 is built in the rear wheel steering mechanism 11 is shown. The rear wheel steering mechanism 11 includes a magnetic pole sensor 18,
The motor housing 40 of the motor 12 and the rear wheel steering angle sensor 21 are integrally provided on a cover 36 fixed to the housing 38. FIG. 3 is a partial cross-sectional view of the rear wheel steering mechanism 11 shown in FIG. The rack shaft 25 is provided at a right angle to the traveling direction of the vehicle. Rack shaft 25
Both ends of are connected to knuckle arms of the rear wheels via ball joints 53. Both ends of the rack shaft 25 are protected by boots 28. A tube 39 is fitted to the right end of the housing 38 in the drawing. Tube 3
By exchanging 9, the length of the rack shaft 25 can be changed without changing the housing 38. A rack 26 is engraved on the rack shaft 25, and the rack 26 meshes with a pinion 27 extending in the front-rear direction of the vehicle. The rack guide cover 32 is fixed to the housing 38, and the rack guide 3
By biasing 1 toward the rack 26, the rack 26
Is pressed to the pinion 27 side. The pinion 27 is fixed to the gear 29 by shrink fitting (press fit) as shown in FIG. 4, and the pin 37 prevents relative rotation.

The rear wheel steering angle sensor 21 is parallel to the surface of the gear 29.
Is provided. The rear wheel steering angle sensor 21 has a built-in potentiometer and detects the rotation angle of the shaft 54. The shaft 54 has
A pin 34 is provided via the lever 33. Pin 3
4 is fitted in a hole 35 provided in the gear 29. As a result, when the gear 29 rotates, the shaft 54 also rotates with it. Since the rotation amount of the gear 29 is proportional to the lateral movement amount of the rack shaft 25, the steering angle amount of the rear wheels can be detected by the rear wheel steering angle sensor 21.

As shown in FIG. 3, the gear 29 is the motor 12
Engages with the pinion 30 provided at the tip of the motor shaft 41 of the. The pinion 30 and the gear 29 form a hypoid gear. This hypoid gear is the motor shaft 4 of the motor 12.
1 rotation is transmitted as rotation of the gear 29, but the rack shaft 2
When trying to rotate the gear 29 from the 5 side, the motor 1
The second motor shaft 41 is set so that the reverse efficiency becomes zero so as not to rotate.

Further, the pinion 30 and the gear 29 form an HRH (high ratio hypoid) gear so as to have a large reduction ratio. The gear ratio is determined by the number of poles of the motor 12, the resolution of the steering angle, etc., and therefore varies depending on the vehicle, but is set to 67: 1 in this embodiment.

A cross section of the motor 12 is shown in FIG. The motor shaft 41 is rotatably supported in the motor housing 40. A four-pole magnet 42 is fixed around the motor shaft 41. A core 43 is fixed to the motor housing 40 so as to face the magnet 42, and a motor winding 44 is wound around the core 43. FIG. 6 shows the motor 12 of FIG.
The AA cross section of is shown. Twelve protrusions 43a extending inward are formed on the core 43, and the motor winding 44
Is wound around this protrusion 43a. FIG. 7 shows how to wind the motor winding 44. FIG. 7 is a view of the motor winding 44 seen from the magnetic pole sensor 18 side. Windings 44a and 44d, 44b and 4
4E, 44c and 44f have terminals U, V and W respectively
Connected to. Winding 44a, 44b, 44c, winding 44
The other ends of d, 44e, and 44f are electrically connected.
The motor winding 44 has a terminal 45 for each system.
It is connected to the wire harness 46 via.

In FIG. 5, one end of the motor housing 40 is an open end, and the magnetic pole sensor 18 is attached thereto. The holder 47 of the substrate 49 is fixed to the open end of the motor housing 40. Three Hall ICs 50 are provided on the substrate 49. A rotor 52 is fixed to the end of the motor shaft 41 of the motor 12. A magnet 51 is provided on the rotor 52. Holder 47
Is covered by a cover 48. The magnet 51 is formed in a disc shape with four poles, as shown in FIG. As shown in FIG. 9, three Hall ICs 50 are arranged on the substrate 49, each being shifted by 60 degrees. 3 holes I
The output of C50 is used as magnetic pole signals HA, HB, HC in the electronic control unit 9 described later.

When the motor shaft 41 rotates, as shown in the rotation state of the magnet 51 in FIG.
The magnet 51 rotates with respect to C), and the three magnetic pole signals HA, HB, and HC that are the three outputs of the magnetic pole sensor 18 change between a high level (H) and a low level (L) as illustrated. FIG. 10 shows a state in which the motor is rotating clockwise (CW). When the motor rotates counterclockwise (CCW), the magnetic pole signals HA, HB, HC of the magnetic pole sensor 18 are switched in the direction from the right to the left in the figure. This magnetic pole signal HA,
If the winding current of the motor winding 44 is switched in synchronism with the switching between HB and HC, the motor will rotate. The current direction when the motor rotates will be described later.

Next, the details of the electronic control unit 9 will be described with reference to FIG. The electronic control unit 9 is a vehicle battery 5
9 is connected. The battery 59 is connected to the power supply terminal PIGA via a fuse. The battery 59 is a fuse and an ignition switch IG.
It is connected to the power supply terminal IGA via SW. The power supply terminal IGA is connected to the constant voltage regulator 55.
The constant voltage regulator 55 outputs a constant voltage Vcc1.

The electronic control unit 9 comprises a microprocessor 1 which is a control means. The first microprocessor 1 operates with a constant voltage Vcc1. The outputs of the first front wheel steering angle sensor 17, the second front wheel steering angle sensor 20, the first vehicle speed sensor 22, the second vehicle speed sensor 23, the yaw rate sensor 24, the magnetic pole sensor 18, and the rear wheel steering angle sensor 21 are output from the interface 57. It is input to the first microprocessor 1 via the. Here, the output of the first front wheel steering angle sensor 17 is θf1, the output of the second front wheel steering angle sensor 20 is θf2,
The output of the first vehicle speed sensor 22 is V1, the second vehicle speed sensor 23
Is V2, the output of the yaw rate sensor 24 is γ, the three outputs of the magnetic pole sensor 18 are HA, HB, HC, and the output of the rear wheel steering angle sensor 21 is θr.

As described above, the electronic control unit 9 includes the motor 1
Control 2 Here, the motor is described as M. The terminals U, V, W of each phase of the motor M are connected to the motor driver 5 of the electronic control unit 9. Here, details of the motor driver 5 will be described with reference to FIG. The motor driver 5 uses the phase switching signals LA11, LB11, LC1.
It is controlled by a phase switching signal group L1 composed of 1, LA21, LB21 and LC21 and a pulse width modulation signal PWM1. The phase switching signals LA11, LB11, LC11 for controlling the high side are input to the gate drive circuit G11 via the abnormal current limiting circuit 88. The abnormal current limiting circuit 88 normally outputs the input signal as it is from the output side. The gate drive circuit G11 includes transistors TA11, TB11, which are power MOSFETs,
The TC 11 is driven on and off. The gate drive circuit G11 also boosts the voltage, and the transistors TA11 and TB1
1, a boosted voltage is applied to the gate of TC11. At the same time, the gate drive circuit G11 changes the boosted voltage to the boosted voltage value RV.
Output as 1. Transistors TA11, TB11,
TC11 is a pattern fuse P from the power supply terminal PIGA.
H, the high voltage obtained via the choke coil TC, and the resistor Rs are respectively applied to the three-phase terminals U, V, and V of the motor M.
It is arranged so that W can be supplied. The transistor TA
11, TB11, TC11, TA21, TB21, TC
A Zener diode is inserted between the gate and the source of 21 to protect the power MOSFET. This is because if the power supply voltage exceeds 20V for some reason, the gate-source voltage of the power MOSFET is 20V.
This is to prevent the power MOSFET from being destroyed when it exceeds V and is destroyed. On the other hand, the phase switching signals LA21, LB21, LC21 for controlling the low side are connected to the gate drive circuit G21 via the pulse width modulation signal synthesis circuit 89 and the abnormal current limiting circuit 88. The pulse width modulation signal synthesis circuit 89 uses the phase switching signals LA21 and LB2.
1 and LC21 are respectively combined with the pulse width modulation signal PWM1. The gate drive circuit G21 drives the transistors TA21, TB21, TC21, which are MOSFETs, on / off. These transistors TA21, TB21,
The TC 21 is arranged so that the three-phase terminals U, V, W of the motor M and the ground of the battery 59 can be connected.
Transistors TA11, TB11, TC11, TA2
1, TB21 and TC21 have a protective diode D3 to
8 are connected to each other. Transistor TA11,
The voltage applied to TB11 and TC11 is the voltage PIGM1.
Is output as. When the difference between this voltage PIGM1 and the boosted voltage value RV1 of the gate drive circuit G11 decreases to about 2V, the transistors TA11 and TB which are MOSFETs
On-resistance of 11, TC11, TA21, TB21, and TC21 may increase, causing abnormal heat generation. Therefore, when the difference between the voltage PIGM1 and the boosted voltage value RV1 of the gate drive circuit G11 becomes a predetermined value or less, all the transistors TA11, TB11, TC11, TA21, TB2.
1, TC21 may be turned off. Incidentally, the transistors TA21, TB21, T connected to the ground
Since a large current flows through the source of C21, it is preferable to wire the ground in a system different from the ground of the weak electric circuit unit such as the microprocessor.

A current detection circuit 86 is provided at both ends of the resistor Rs and detects the value of the current flowing through the resistor Rs.
Further, in the current detection circuit 86, the value of the current flowing through the resistor Rs is 1
When it is 8 A or more, it is determined to be an overcurrent, and the overcurrent signal is output from the output signal MOC1. Further, the current detection circuit 86 determines that the current is an abnormal current when the current value flowing through the resistor Rs is 25 A or more, and outputs an abnormal current signal from the output signal MS1. When an overcurrent occurs, an overcurrent signal is given to the pulse width modulation signal synthesis circuit 89 to limit the low side. When an abnormal current occurs, the abnormal current limiting circuit 88
An abnormal current signal is applied to and the high side and low side are limited. In this case, all transistors TA1
1, TB11, TC11, TA21, TB21, TC2
1 may be turned off for a certain period of time after the abnormal current is detected. This fixed time is FE for the maximum expected current
It may be set to be within the safe operation area of T.

The current value detected by the current detection circuit 86 is given to the peak hold circuit 101. The peak hold circuit 101 outputs the peak value of the current value to the peak signal MI1.
Output as. The peak hold circuit 101 is reset at the timing when the reset signal DR1 switches.

Next, the rotating operation of the motor M will be described with reference to FIG. 10 again. If the pattern of the phase switching signal is set as shown in Table 1 according to the states of the magnetic pole signals HA, HB, HC, the motor M rotates. Clockwise rotation (CW)
Is set to the right and the counterclockwise rotation (CCW) is set to the left. It is assumed that the magnetic pole signal is (HA, HB, HC) = (H, L, H) as in the case of clockwise rotation 1 in Table 1. At this time, the phase switching signals (LA11, LB1
1, LC11, LA21, LB21, LC21) =
(H, L, L, L, H, L) is output. This state shows the state in the range of A in FIG. As shown in the rotating state of the magnet 51 of the magnetic pole sensor 18, the inner magnetic pole signals HA and HC of the three Hall ICs are at a high level. The direction of the winding current changes from U to V. At this time, the motor rotates and the magnet 51 rotates clockwise in the drawing. When the magnet 51 rotates about 30 degrees, the magnetic pole signal HA switches from high level to low level. In accordance with this, the phase switching signal (LA1
1, LB11, LC11, LA21, LB21, LC2
1) = (H, L, L, L, H, L), the motor will rotate continuously. As described above, in order to apply the clockwise rotation (CW) or the counterclockwise rotation (CCW) to the motor, the pattern of the phase switching signal may be switched according to the order of Table 1.

[0025]

[Table 1]

The failure of the motor M can be detected by the peak hold value of the peak hold circuit 101 in addition to the above-mentioned abnormal current value. In the motor M, U phase −
Since current flows between V-phase, between V-phase and W-phase, or between W-phase and U-phase, the peak value should always be the same level if the current flowing through the motor is peak-held at each phase switching. . Here, for example, if the U phase is disconnected,
No current flows between U-phase and V-phase or between W-phase and U-phase, and V
The peak value of the current becomes high only when flowing between the phase and the W phase. When the U phase is short-circuited, the current doubles between the U phase and the V phase or between the W phase and the U phase, and the peak value of the current becomes low only when the current flows between the V phase and the W phase. Therefore, if the peak value for each phase switching is not at the same level for three consecutive times, it can be determined that one of the phases is abnormal. Also, the motor current can be estimated from the motor rotation speed and PWM. If the peak hold value of the current deviates from this estimated value, it can be determined that the motor is abnormal.

In FIG. 11, the motor driver 5 obtains electric power from power supply terminals PIGA and IGA. A phase switching signal group L1 which is a signal output from the first microprocessor 1 is input to the motor driver 5 (L1 is a phase switching signal LA11, LB11, LC11, LA21, LB2.
1, a signal group consisting of LC21) and a pulse width modulation signal PWM.

Next, the structure of the microprocessor 1 is shown in FIG.
3 shows. When the control of the microprocessor 1 is represented by a block diagram, the target rudder angle calculation unit 60, the motor servo control unit 6
1, a phase switching control unit 62, a magnetic pole sensor abnormality determination unit 63, an open control unit 64 and a switch SW1. The configuration of the microprocessor 1 will be described below.

The target steering angle calculation unit 60 calculates the target steering angle value AGLA from the yaw rate value γ, the vehicle speed V and the steering angle θs.
Ask for. Although not shown, the vehicle speed V is obtained from the output values V1 and V2 of the two vehicle speed sensors 22 and 23. At this time, the average of the two vehicle speed values may be the vehicle speed V, or the maximum value of the two vehicle speed values may be the vehicle speed V. By detecting the vehicle speed with two systems, it is possible to detect an abnormality of the vehicle speed sensor. Although not shown, the front wheel steering angle θs
Are output values θf1, θ of the two front wheel steering angle sensors 17, 20
Calculate from f2. Normally, a potentiometer is used for the first front wheel steering angle sensor 17, but the potentiometer has a rough accuracy. Further, if a rotary encoder is used for the second front wheel steering angle sensor 20, the steering angle amount can be accurately detected, but the initial steering angle amount cannot be detected. Therefore, the absolute value of the output of the second steering angle sensor 20 is calculated by the first front wheel steering angle sensor 17, and after the absolute value is calculated, the output of the second front wheel steering angle sensor 20 is used as the steering angle θs.

FIG. 14 shows a control block diagram of the motor servo control unit 61. The differentiating part 90 differentiates the target steering angle value AGLA to obtain a differential value SAGLA. Differential gain setting unit 91
Is the differential gain YTD from the differential value SAGLA of the target steering angle value.
Ask for IFGAIN. Here, the differential gain YTDIFGAIN is obtained from the absolute value of the differential value SAGLA. When the absolute value of the differential value SAGLA is 4 deg / Sec or less, the differential gain is 0 and the absolute value of the differential value SAGLA is 12d.
When it is equal to or more than eg / Sec, the differential gain is set to 4, and the absolute value of the differential value SAGLA is 4/12 deg / Se.
In the case of c, the differential gain has a value of 0 to 4. Motor M
The rotation angle θm of is obtained from the output of the magnetic pole sensor 18. Although not shown, the motor rotation angle θm is obtained from the output values HA, HB, HC of the magnetic pole sensor 18 and the output value θr of the rear wheel steering angle sensor 21. Normally, a potentiometer is used for the rear wheel steering angle sensor 21, but the potentiometer has a rough accuracy.
Further, although the magnetic pole sensor 18 can accurately detect the steering angle amount, it cannot detect the initial steering angle amount. Therefore, the rear wheel steering angle sensor 21 obtains the absolute value of the magnetic pole sensor 18, and after obtaining the absolute value, the motor rotation angle θm is obtained from the change in the output of the magnetic pole sensor 18. Rotation angle θm is buffer 1
The actual steering angle value RAGL is given to the subtraction unit 92 via 00. The subtraction unit 92 subtracts the actual steering angle value RAGL from the target steering angle value AGLA to obtain the steering angle deviation ΔAGL. This steering angle deviation ΔAGL is processed via the deviation steering angle dead zone imparting section 93. The deviation steering angle dead zone applying unit 93 determines the steering angle deviation ΔAG.
When the absolute value of L is equal to or smaller than the predetermined value E2PMAX, the steering angle deviation value ETH2 is set to 0, and the steering angle deviation Δ
When the value of AGL is small, the control is stopped. The obtained steering angle deviation value ETH2 is sent to the proportional section 96 and the differentiating section 94. The proportional portion 96 determines the steering angle deviation value ETH2.
Is multiplied by a predetermined proportional gain to obtain a proportional term PAGELA. Further, the differentiating unit 94 differentiates the steering angle deviation value ETH2,
The steering angle deviation differential value SETH2 is obtained. Steering angle deviation derivative SE
TH2 and the above-mentioned differential gain YTDIFGAIN are integrated by the integration unit 95, and the differential term DAGLA is obtained.
The proportional term PAGLA and the differential term DAGLA are added by the adder 97 to obtain the steering angle value HPID. Rudder angle value HPID
The deviation steering angle limiter 98 limits the steering angle.
The deviation steering angle limiter 98 has a control amount ANG that is the steering angle value HPID.
Is controlled in proportion to the control amount A so that the control amount does not become 1.5 deg or more or −1.5 deg or less.
Give NG. The control amount ANG is the pulse width modulation conversion unit 99.
Is converted into a pulse width modulated signal by the motor driver 5
Sent to. The motor driver 5 rotates the motor M according to the pulse width modulation signal. In this way, the motor M is servo-controlled. Further, the steering angle deviation is PD-controlled.
Among these, the differential gain of the differential term is changed according to the differential value of the target steering angle value. The differential gain becomes 0 when the differential value of the target steering angle value is small, and the control is performed only by the proportional term.
An integral term may be added to the PD control. Further, since the rotation angle of the motor M changes depending on the fluctuation of the power supply voltage, the battery voltage may be measured and the control amount AGL may be corrected according to the battery voltage.

Microprocessor magnetic pole sensor signal H
At the input terminals of A, HB, and HC, as shown in FIG.
The interrupt terminal and the normal input terminal of the microprocessor 1 are used. The magnetic pole sensor signals HA and HB are connected to the input terminals of the exclusive OR circuit EXOR1.
Magnetic pole sensor signal HC and exclusive OR circuit EXO
The output terminal of R1 is an exclusive OR circuit EXOR2
Is connected to the input terminal of. Magnetic pole sensor signals HA, H
When any one of B and HC changes, the output of the exclusive OR circuit EXOR2 changes.

When there is a change in any one of the magnetic pole sensor signals HA, HB, HC, the microprocessor 1
A magnetic pole sensor signal edge interrupt routine as shown in FIG. 16 is executed. This magnetic pole sensor signal edge interrupt routine recognizes the magnetic pole sensor signal and
The function of the magnetic pole sensor abnormality determination unit 63 is fulfilled.

Here, each time there is an interruption, the state of the magnetic pole sensor signal is read and stored as the current value, and at the same time, the current value stored so far is updated as the previous value.

In FIG. 16, in step 200, the magnetic pole sensor signal stored so far is updated as the previous value. Next, at step 201, the magnetic pole sensor signal HA,
The states of the input terminals of HB and HC are read and stored as current values. Next, at step 202, the previous predicted value is read from the map shown in Table 2. As will be described later, the magnetic pole sensor 18 is one of the magnetic pole sensor signals HA, HB, and HC.
Are configured to change in sequence. Therefore, the polarity of any one of HA, HB, and HC should change from the previous value and the current value. Table 2
All possible states for the current value are stored in the previous predicted value of the map. Specifically, this time the value is (HA,
When HB, HC) = (L, L, H), the previous predicted value becomes (H, L, H) or (L, H, H). Figure 1
In step 203 of 6, the previous predicted value is compared with the actual previous value. If the magnetic pole sensor 18 is functioning normally, the previous predicted value and the previous value should match. If the previous predicted value and the previous value match, the abnormality flag Fabn is set to 0 in step 204. If the previous predicted value and the previous value do not match, the abnormal flag F is determined in step 205.
Let abn be 1. After that, the magnetic pole sensor signal edge interrupt routine is ended. As a result, in the subsequent processing, if the abnormality flag Fabn is 1, it can be known that the magnetic pole sensor 18 has an abnormality.

[0035]

[Table 2]

FIG. 17 is a flow chart showing the operation of the phase switching control unit 62 shown in FIG. In step 210, if the above-mentioned abnormality flag Fabn is 1, the following processing is skipped. That is, the phase switching control routine is not executed when the magnetic pole sensor 18 is abnormal. Step 21
At 1, it is determined whether or not there is an edge interrupt of the magnetic pole sensor signal. If there is an interrupt, step 2
At 12 to 214, the value CW is set to the direction flag DI if the clockwise rotation is to be performed, and the value CCW is set to the direction flag DI if the counterclockwise rotation is to be performed. The rotation direction can be determined by whether the steering angle value HPID is positive or negative. If HPID> 0, direction flag DI = CC
If W and HPID <0, the direction flag DI = CW. Next, in step 215, the phase switching signal pattern is set based on the map in Table 3 below. The phase switching signal is a 6-bit signal, and each bit is defined as shown in Table 4 below. Each bit can have a high level “H” and a low level “L”. In step 215, the next phase switching pattern is set from the state of the phase switching pattern and the direction flag DI that have been output so far. For example, if the current value is (L
A11, LB11, LC11, LA21, LB21, L
C21) = (H, L, L, L, H, L) and DI
= CW (clockwise rotation), (H, L, L, L, L, H) is set as the next value. The set phase switching pattern is calculated in the microprocessor 1 as a phase switching signal group L1. Here, if the control cycle is early, this phase switching control routine may be performed in the magnetic pole sensor signal edge interrupt routine.
When setting the direction flag, if the steering angle value HPID is zero, the phase switching is set to the stop mode, and (LA11, LB
11, LC11, LA21, LB21, LC21) =
(L, L, L, L, L, L) may be output.

[0037]

[Table 3]

[0038]

[Table 4]

FIG. 18 is a flow chart showing the operation of the open control unit 64 shown in FIG. Step 220
Then, if the above-mentioned abnormality flag Fabn is 0, the following processing is skipped. That is, the open control routine is not executed when the magnetic pole sensor 18 is normal. Therefore, when the magnetic pole sensor 18 is normal, the above-described phase switching control routine is executed, and when the magnetic pole sensor 18 is abnormal, this open control routine is executed. In this open control routine, the open control in-execution flag Fop1 and the timer T are used. When the timer T is set to the predetermined time, the timer T is gradually decremented after that, and becomes 0 after the predetermined time. Open control execution flag Fop1
Is initially set to 0. In step 221, the state of the open control in-execution flag Fop1 is judged, and if the open control in-execution flag Fop1 is 0,
Next, at step 222, the timer T is set to a predetermined time (for example, 1 second). Then, in step 224, the motor brake pattern is set as the phase switching pattern until the timer T becomes 0 or less. The motor brake pattern is (LA11, LB11, LC11, LA
21, LB21, LC21) = (L, L, L, H, H,
H), (LA12, LB12, LC12, LA22, L
B22, LC22) = (L, L, L, H, H, H) is set. When the predetermined time has elapsed, the open control execution flag Fop1 is set to 1 in step 225. Next, since the timer T is 0 or less in this state, the next phase switching pattern is set from the map shown in Table 5 in step 227. Next, at step 228, the timer T is set again. In step 226, step 227 is executed only when the timer T is 0 or less, so step 227 is executed every predetermined time set in the timer T. In step 227, the next value is set according to the current phase switching pattern and the result of comparison between the rear wheel steering angle value θr output from the rear wheel steering angle sensor 21 and the predetermined value A1. A1 is set to a value close to zero (for example, 0.5 degrees). For example, the current phase switching pattern is (LA1
1, LB11, LC11, LA21, LB21, LC2
1) = (H, L, L, L, H, L) and when the rear wheel steering angle value θr is −1 degree, the next phase switching pattern is (H, L, L, L). , L, H). The map of Table 5 is set so that when the rear wheel steering angle value is negative, it rotates to the right, and when the rear wheel steering angle value is positive, it rotates to the left. In any case, the absolute value of the rear wheel steering angle acts so as to approach zero. When the absolute value of the rear wheel steering angle becomes a predetermined value A1 or less,
The phase switching pattern is (L, L, L, L, L, L).
In the case of this pattern, the motor 12 is stopped. Therefore,
In the open control routine, the phase switching pattern is controlled so that the rear wheel steering angle becomes zero and the neutral return is performed.

[0040]

[Table 5]

Although the magnetic pole sensor 18 is used as the rotation sensor of the brushless motor in the present embodiment, an encoder such as a light pulse type sensor using a light emitting diode may be used.

As described above, in the present embodiment, the motor shaft 41, the magnetic pole sensor 18 that is a rotation sensor for detecting the rotation of the motor shaft, and the phase switching pattern according to the output change of the rotation sensor. In the brushless motors 12, M provided with a phase switching control unit 62 which is a phase switching control unit for switching and outputting, after the phase switching control unit switches and outputs the phase switching pattern L1, the brushless motor rotates clockwise or counterclockwise. When the actual output signal of the magnetic pole sensor is different from the expected signal of the rotation sensor, the magnetic pole sensor abnormality determining unit 63 is provided as abnormality determining means for determining abnormality. Therefore, when the motor shaft 41 does not rotate despite switching the output or when the magnetic pole sensor 18 fails, an abnormality can be promptly detected.

Therefore, the subsequent stop processing of the motors 12 and M (step 224) and the open control (step 22).
It is possible to surely perform neutral return and the like by 7).

[0044]

As described above, according to the first aspect of the invention, the abnormality can be promptly detected when the motor shaft does not rotate or the rotation sensor fails even though the output is switched. Therefore, the subsequent stop and open control of the motor can be reliably performed.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an embodiment of the present invention.

FIG. 2 is a front view of a rear wheel steering mechanism used in an embodiment of the present invention.

3 is a partial cross-sectional view of the rear wheel steering mechanism of FIG.

4 is a cross-sectional view of the rear wheel steering mechanism of FIG.

FIG. 5 is a sectional view of a motor used in an embodiment of the present invention.

FIG. 6 is a sectional view of a motor used in an embodiment of the present invention.

FIG. 7 is an explanatory view of windings of the motor shown in FIGS.

FIG. 8 is a front view of a magnet used in an example of the present invention.

FIG. 9 is a front view of the substrate of the magnetic pole sensor used in the embodiment of the present invention.

FIG. 10 is an operation explanatory view of the brushless motor of the present invention.

FIG. 11 is a circuit configuration diagram of an electronic control device used in an embodiment of the present invention.

FIG. 12 is a circuit configuration diagram of a driver of the electronic control device of FIG.

13 is a functional block diagram of a microprocessor of the electronic control unit of FIG.

14 is a functional block diagram of a motor servo control unit of the microprocessor shown in FIG.

FIG. 15 is a circuit configuration diagram of a magnetic pole sensor input circuit of the electronic control device of FIG. 11.

16 is a flowchart of a magnetic pole sensor abnormality determination unit in FIG.

FIG. 17 is a flowchart of the phase switching control unit in FIG.

FIG. 18 is a flowchart of the open control unit in FIG.

[Explanation of symbols]

1 Microprocessor 5 Motor Driver 9 Electronic Control Device 10 Front Wheel Steering Device 11 Rear Wheel Steering Mechanism 12 Motor (Brushless Motor) 13,14 Front Wheel 15,16 Rear Wheel 17,20 First and Second Front Wheel Steering Angle Sensor 18 Magnetic Pole Sensor ( (Rotation sensor) 19 Steering wheel 21 Rear wheel steering angle sensor 22, 23 First and second vehicle speed sensor 24 Yaw rate sensor 25 Rack shaft 26 Rack 27 Pinion 28 Boot 29 Gear 30 Pinion 31 Rack guide 32 Rack guide cover 33 Lever 34 pin 35 Hole 36 Cover 37 Pin 38 Housing 39 Tube 40 Motor Housing 41 Motor Shaft 42 Magnet 43 Core 43a Protrusion 44 Motor Winding 44a, 44b, 44c, 44d, 44e, 44f Winding 45 Terminal 46 Wire Ha Nes 47 Holder 48 Cover 49 Substrate 50 Hall IC 51 Magnet 52 Rotor 53 Ball Joint 54 Axis 55 Constant Voltage Regulator 57 Interface 59 Battery 60 Target Steering Angle Calculation Unit 61 Motor Servo Control Unit 62 Phase Switching Control Unit 63 Magnetic Pole Sensor Abnormality Judgment Unit ( Abnormality determining means) 64 Open control unit 86 Current detection circuit 88 Abnormal current limiting circuit 89 Pulse width modulation signal combining circuit 90, 94 Differentiating unit 91 Differential gain setting unit 92 Subtracting unit 93 Deviation steering angle dead zone applying unit 95 Integrating unit 96 Proportional unit 97 adder 98 deviation steering angle limiter 99 pulse width modulation converter 100 buffer 101 peak hold circuit AGLA target steering angle value ANG control amount D1-8 diode DAGLA differential term DR1 reset signal E2PMAX predetermined value ETH2 steering Angle deviation value EXOR1, EXOR2 Exclusive OR circuit G11, G21 Gate drive circuit HA, HB, HC
Magnetic pole signal HPID Steering angle value IGA Power supply terminal IGSW Ignition switch L1 Phase switching signal group LA11, LB11, LC11, LA21, LB21,
LC21 Phase switching signal M Motor (brushless motor) MI1 Peak signal MOC1, MS1
Output signal PGLA Proportional term PH Pattern fuse PIGA Power supply terminal PIGM1 Voltage PWM1 Pulse width modulation signal RAGL Real steering angle value Rs Resistance RV1 Boosted voltage value SAGLA Differential value SETH2 Steering angle deviation differential value SW1 switch TA11, TB11, TC11, TA21, TB21,
TC21 Transistor TC Choke coil U, V, W terminals V Vehicle speed Vcc1 Constant voltage YTDIFGAIN Differential gain ΔAGL Steering angle deviation γ Yaw rate value θm Rotation angle θs Steering angle In parentheses, the name of the configuration of the embodiment corresponds Represents the name of the configuration of the claim when the name is different from.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazutaka Tamura Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Co., Ltd. (72) Inventor Taichi Matsumoto 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Vehicle Co., Ltd. (72) Inventor Hidemori Tsuka, 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Co., Ltd.

Claims (1)

[Claims] 1. A brushless motor comprising: a motor shaft; a rotation sensor for detecting rotation of the motor shaft; and a phase switching control means for switching and outputting a phase switching pattern according to an output change of the rotation sensor, The output signal of the actual rotation sensor is different from the expected signal of the rotation sensor expected when the brushless motor is rotated to the right or left after the phase switching control means switches and outputs the phase switching pattern. In this case, a brushless motor abnormality detection device including abnormality determination means for determining abnormality.