JPH08168288A - Current controller for electric motor - Google Patents

Abstract

PURPOSE: To suppress the current value of an electric motor to a smaller value than a current limiting value without connecting any current detector to a motor conducting loop by giving an upper limit signal to a motor driver when an indicating signal indicating the voltage applied across the motor exceeds the upper limit value or the indicating signal when the indicating signal is lower than the upper limit signal. CONSTITUTION: A speed detecting means 63 detects the rotating speed N of an electric motor and a conduction control means 61B calculates the upper limit signal VL of the voltage applied across the motor corresponding to the rotating speed N and current limiting value IL. The means 61B gives the upper limit signal Vout=VL to a motor driver 5 when the indicating signal Vc of a servo controller 61A indicating the voltage applied across the motor exceeds the upper limit signal VL or the indicating signal Vout=Vc to the driver 5 when the indicating signal Vc is lower than the upper limit signal VL. Namely, the indicating signal Vout indicating the voltage applied across the motor and given to the driver 5 from the controller 61 is limited to the upper limit signal VL.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for controlling a current supplied to an electric motor, and more particularly to a control device for preventing a current exceeding a limit value from flowing in the electric motor.

[0002]

2. Description of the Related Art Conventionally, as a method of monitoring an electric current supplied to an electric motor and preventing an overcurrent from flowing, generally, a current flowing to a motor driver for driving the electric motor or an electric current directly supplied to the electric motor is used. Current,
It is detected by some detecting means, and the feedback control of the motor current is carried out so that the detected value becomes equal to or less than the limit value (for example, Japanese Patent Publication No. 6-15331). JP-A-6-2847
In Japanese Patent Publication No. 77, the motor current reference value Is is calculated based on the motor rotation speed Nm, the power supply voltage Vps, and the motor PWM energization duty ratio Dr, and the current detector detects it. -A motor abnormality detection is proposed which monitors the motor current Im and determines that the motor is abnormal when Im is out of the range of Is ± α.

[0003]

SUMMARY OF THE INVENTION In order to detect a motor current abnormality (detection of short circuit abnormality or disconnection abnormality), a motor is used.
The most reliable method is to monitor or monitor the motor current by inserting or connecting a current detector to the current-carrying loop. However, there is current consumption (voltage drop) in the current detector, There is a problem that the current detector which is not expensive is expensive.

In the current limit (current limiter) for preventing overload (overcurrent) of the motor, the motor driver, the servo controller and / or the power supply, not only in terms of price, but also in design. Alternatively, it may be difficult to use the current detector for reasons of use, or overcurrent detection may not always be necessary. For example, motor + motor driver + server
In the combination of the vocontroller and the power supply, if at least one of them is smaller than the other power capacity, wants to temporarily reduce it, or suppresses the response speed, or motor drive control In the above, when the power consumption control, function control, or response control of the above combination is performed from another control system other than the motor control system according to the above combination, the overcurrent detection is omitted and the current limit ( The current limiter alone may not cause any problems.

The present invention provides a current control device which suppresses the motor current value to a predetermined current limit value or less without inserting or connecting a current detector to the motor energization loop. With the goal.

[0006]

SUMMARY OF THE INVENTION An electric motor current controller according to the present invention is a motor driver (5) for energizing a winding (44) of an electric motor (12); an electric motor applied voltage. Instruction signal
Servo controller (61A) for generating (Vc); Speed detection means (63) for detecting the rotation speed (N) of the electric motor; Rotation speed (N) and current limit value (IL) detected by the speed detection means ) Means for calculating the electric motor applied voltage upper limit signal (VL)
(61B); and when the value represented by the instruction signal (Vc) exceeds the value represented by the upper limit signal (VL), the upper limit signal (V
out = VL), when the value represented by the instruction signal (Vc) is less than or equal to the value represented by the upper limit signal (VL), the instruction signal (Vout = V
c) is provided with an energization control means (61B) for supplying the motor driver. The symbols in parentheses are symbols attached to corresponding elements or corresponding matters in the embodiments shown in the drawings.

[0007]

[Function] The speed detection means (63) is the rotation speed (N) of the electric motor.
The calculation means (61B) detects that the electric motor applied voltage upper limit signal (VL) corresponding to the high speed (N) and the current limit value (IL).
To calculate. There is a relationship shown in FIG. 15 between the rotational speed N and the electric current I of the electric motor and the generated torque T.
Between the applied voltage V and the rotation speed N and the current I
There is a relation of = R · I + K · N. R is the electric resistance of the motor, and K is a constant determined by the motor. The motor applied voltage VL for setting the current I to the current limit value IL is V
L = R.IL + K.N, and in order to suppress the motor current I below IL, the motor applied voltage V is VL = R.IL +
It may be suppressed to K · N or less. In the later-described embodiment of the present invention, according to this, the electric motor applied voltage upper limit signal (VL)
Is calculated by VL = R · IL + K · N.

The energization control means (61B) is a servo controller.
When the value indicated by the electric motor applied voltage instruction signal (Vc) generated by the motor (61A) exceeds the value indicated by the upper limit signal (VL), the instruction signal (Vc) indicates the upper limit signal (Vout = VL). When the value is less than or equal to the value indicated by the upper limit signal (VL), the instruction signal (Vout = V
c) is given to the motor driver (5). That is, the electric motor applied voltage instruction signal (Vout) given from the servo controller (61A) to the motor driver (5) is limited to the upper limit signal (VL). Therefore, to explain according to the embodiment, the motor applied voltage Vout = R · I + K · N ≦ VL = R · IL + K ·
N, R · I ≦ R · IL, that is, the motor current I ≦
It becomes the current limit value IL.

A motor drive control device using a servo controller (61A) is generally equipped with a means for detecting the rotational speed of the motor (for example, a rotary encoder) and a speed detecting means. Since this can be used as (63), the adoption of the speed detecting means (63) does not cause any extra burden. The current detector body and the sensing circuit for driving the current detector and processing the data, which have been conventionally required, are omitted, and the cost of the current limiting system and the downsizing of the system can be realized. Not only that, the motor current upper limit value is changed by giving or setting to the means (61B) for calculating the electric motor applied voltage upper limit signal (VL) or changing the current limit value (IL). Therefore, there is a high degree of freedom in setting and changing the current upper limit value, and it is easy to change the current limit value (IL) with the output of another control system.

Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the structure of a front and rear wheel steering system of a vehicle equipped with an embodiment 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 provided on the steering shaft to which the first front wheel steering angle sensor 17 and the steering wheel 19 for detecting the amount of movement of the rack (the operation shaft for steering driving of the front wheels) of the front wheel steering device 10 are attached. It is detected by the second front wheel steering angle sensor 20. 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 a rear wheel steering mechanism 11. The rear wheel steering mechanism 11 is a brushless motor 1
Operates with power of 2. At the end of the motor 12, the motor 1
A magnetic pole sensor 18 for detecting the rotation angle of 2 is provided. In addition, the rear wheel steering sensor 21 for detecting the actual steering angle of the rear wheels 15 and 16 has an operation shaft 25 for steering and driving the rear wheels.
Is joined to.

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,
The respective sensor outputs of the rear wheel steering sensor 21, the first vehicle speed sensor 22, the second vehicle speed sensor 23, and the yaw rate sensor 24 are received, and the current rotational speed N (rotational speed / minute) of the motor 12, namely, The rotation speed is calculated, and the control signal PWM1 output to the motor driver 5 that drives the motor 12 is controlled so that the current supplied to the motor 12 at the rotation speed N does not exceed the current limit value IL.

The main part of the rear wheel steering mechanism 11 is shown in FIG.
Operation shaft 2 provided at right angles to the traveling direction of the vehicle
A knuckle arm (not shown) of a rear wheel is connected to both ends of 5 via ball joints 53. Both ends of the operating shaft 25 are protected by boots 28.

The operating shaft 25 penetrates the hollow rotary shaft 27 of the brushless motor 12. A substantially cylindrical male screw member 26 is fixed to the operation shaft 25. A trapezoidal female screw 27sf is engraved on the inner peripheral surface of the hollow rotary shaft 27 that bulges to a large diameter, and a trapezoidal female screw 27sf is screwed to the outer peripheral surface of the male screw member 26 that bulges to a large diameter. The trapezoidal male screw 27sm is engraved, and these trapezoidal female screw 27sf
Also, a trapezoidal male screw 27sm is screwed at a position E2 shown in FIG. A female screw member 26 integrally fixed to the operation shaft 25 has a distal end of an arm extending in the radial direction, one end of which is fixed to the rotary shaft of the rear wheel steering angle sensor 21 which is a rotary reponsion tensioner. Engaged. The rotation axis of the rear wheel steering angle sensor 21 is displaced from the axis of the operation shaft 25 in the direction perpendicular to the plane of the drawing of FIG. 2 by the length of the arm. As a result, when the operation shaft 25 moves forward and backward in the direction in which the axis of the operation shaft extends (steering drive direction), the rotation axis of the rear wheel steering angle sensor 21 rotates forward and backward, and the output signal of the rear wheel steering angle sensor 21. The level corresponds to the position of the operation shaft 25 (rear wheel steering angle).

The hollow rotary shaft 27 of the motor 12 passes through and is fixed to a four-pole cylindrical magnet 42. The side circumferential surface of the magnet 42 is surrounded by a substantially cylindrical magnetic yoke 43, and a magnetic pole 43a (FIG. 3) projects from the magnetic yoke 43 toward the magnet 42, and the magnetic coil 43a has an electric coil. There are 44 wound around.

FIG. 3 shows a cross section taken along line 3A-3A in FIG.
Twelve magnetic poles 43a from the yoke 43 toward the magnet 42
Is projected, and each coil of the electric coil 44 is wound around each of the magnetic pole groups having three protrusions as one unit. How to wind the electric coil 44 is shown in FIG. FIG. 4 is a view of the electric coil 44 seen from the magnetic pole sensor 18 (FIG. 2) side. The electric coil 44 is wound in six phases. The electric coils 44a and 44d are connected to the terminal U, and the electric coils 44b and 44d are connected.
e is connected to the terminal V, and the electric coils 44c and 44f are connected to the terminal W, respectively. Thus, the motor 12 has three
It is a phase 4 pole brushless motor. Electric coil 4
4 is connected to a motor driver 5 (FIG. 9) via a terminal and a wire harness for each system.

The magnetic pole sensor 18 shown in FIG. 2 is shown in FIG.
The holder 47 of the board 49 is fixed to the motor housing. Three Hall ICs 50 are provided on the substrate 49. As shown in FIG. 5, three Hall ICs 50 are arranged on the substrate 49 with a shift of 60 degrees each. The outputs of the three Hall ICs 50 are used as magnetic pole signals HA, HB, HC in the electronic control unit 9 described later.

When the hollow rotating shaft 27 of the motor 12 (hereinafter referred to as the motor shaft 27) rotates, as shown in the rotating state of the magnet 42 in FIG. As a result, the magnet 42 rotates, and the magnetic pole signals HA, HB, and HC, which are the three outputs of the magnetic pole sensor 18, change between a high level (H) and a low level (L) as shown in the figure. FIG. 6 shows a state in which the motor is rotating clockwise (CW). When the motor rotates counterclockwise (CCW), the magnetic pole signals HA and H of the magnetic pole sensor 18 move from the right to the left in the drawing.
B and HC are switched. This magnetic pole signal HA, HB, HC
When the electric current of each electric coil of the electric coil 44 is switched in synchronism with the switching of the above, the magnet 42, that is, the rotor rotates. The current direction when the rotor is rotationally driven will be described later.

FIG. 7 shows the configuration of the electronic control unit 9 shown in FIG. The electronic control unit 9 is connected to a vehicle-mounted battery 59. The battery 59 is connected to the power supply terminal PIGA via a fuse and a relay 77, and the relay 77 is opened / closed by a relay drive circuit 79. Further, the battery 59 is connected to the power supply terminal IGA via a fuse and an ignition switch IGSW.
The power supply terminals IGA are each connected to a constant voltage regulator 55, and the constant voltage regulator 55 has a constant voltage Vcc.
Outputs 1.

The electronic control unit 9 comprises a microprocessor 1 which is the main control means.
Operates with a constant voltage Vcc1. The electronic control unit 9 includes the above-mentioned first front wheel steering angle sensor 17, second front wheel steering angle sensor 20, first vehicle speed sensor 22, second vehicle speed sensor 23,
The outputs of the yaw rate sensor 24, the magnetic pole sensor 18, and the rear wheel steering angle sensor 21 are input. Here, the first
The output of the 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 V
1, output of the second vehicle speed sensor 23 is V2, output of the yaw rate sensor 24 is γ, three outputs of the magnetic pole sensor 18 (hereinafter, magnetic pole sensor signals) are outputs of HA, HB, HC, and rear wheel steering angle sensor 21. Is θr. Output θf1 of first front wheel steering angle sensor 17 and output θf of second front wheel steering angle sensor 20
2 is input to the signal processing circuit P1 inside the electronic control unit 9, and the signal processing circuit P1 outputs the output values θf1 and θf2.
The steering angle θs is calculated based on Usually first
Although a potentiometer is used for the front wheel steering angle sensor 17, 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.
The output V1 of the first vehicle speed sensor 22 and the output V2 of the second vehicle speed sensor 23 are input to a signal processing circuit P2 inside the electronic control unit 9, and the signal processing circuit P2 outputs those output values V1 and V2.
The vehicle speed V is calculated based on 2. 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.

Steering angle θs, vehicle speed V, output γ of yaw rate sensor 24, magnetic pole sensor signals HA, HB, H
C and the output θr of the rear wheel steering angle sensor 21 are input to the microprocessor 1 via the interface 57.

The magnetic pole sensor signals HA, HB, and HC output from the interface 57 are output to the microprocessor 1
In parallel with the exclusive OR circuit P3. FIG. 8 shows the internal logic of the exclusive OR circuit P3. As shown in FIGS. 7 and 8, the magnetic pole sensor signals HA, HB, and HC output from the interface 57 are respectively input to the normal input terminals Ha, Hb, and Hc of the magnetic pole sensor signals HA, HB, and HC of the microprocessor 1. The interrupt data S1 directly input and output from the exclusive OR circuit P3 is input to the interrupt terminal.
The output data lines of the magnetic pole sensor signals HA and HB extracted from the microprocessor 1 are the microprocessor 1
Exclusive input O in parallel with normal input terminals Ha and Hb
It is connected to the input terminal of the R circuit EXOR1. The data line of the magnetic pole sensor signal HC output from the interface 57 is the normal input terminal Hc of the microprocessor 1.
Is connected in parallel with one of the input terminals of the exclusive OR circuit EXOR2, and the exclusive OR circuit EXO
An exclusive OR is applied to the other input terminal of R2.
The output terminal of the circuit EXOR1 is connected. When any one of the magnetic pole sensor signals HA, HB, HC changes, the output of the exclusive OR circuit EXOR2 changes.

The microprocessor 1 inputs each data (θs, V, γ, S1, HA, HB, HC, θr).
Then, the control signals PWM1 and L1 are calculated, and the motor 12 is controlled via the motor driver 5. Here, the functions of the motor driver 5 and the motor 12 will be described in order to facilitate understanding of the functions of the microprocessor 1.

Details of the motor driver 5 will be described with reference to FIG. The motor driver 5 uses the phase switching signal LA11,
Phase switching signal group L1 including LB11, LC11, LA21, LB21, LC21 and pulse width modulation (Pulse Width)
Modulation) signal PWM. Phase switching signals LA11, LB11, L for controlling the high side
C11 is input to the gate drive circuit G11. The gate drive circuit G11 drives the transistors TA11, TB11, TC11, which are power MOSFETs, on and off, and also boosts the voltage, so that the transistors TA11, TB11,
A boosted voltage is applied to the gate of TC11. At the same time, the gate drive circuit G11 outputs the boosted voltage as the boosted voltage value RV1. Transistors TA11, TB11, TC1
1 is arranged so that a high voltage obtained from the power supply terminal PIGA via the pattern fuse PH and the choke coil TC can be supplied to the three-phase terminals U, V, W of the motor 12, respectively. The transistors TA11 and TB1
Zener diodes are inserted between the gates and sources of 1, TC11, TA21, TB21, and TC21 to protect the power MOSFET. this is,
If the power supply voltage exceeds 20V for some reason, the power M
This is to prevent the gate-source voltage of the OSFET from exceeding 20 V and destroying the power MOSFET. In this case, the relay 77 is turned off and the transistor drive signal is also turned off to protect the circuit. 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. The pulse width modulation signal synthesis circuit 89 synthesizes the phase switching signals LA21, LB21, LC21 with the pulse width modulation signal PWM1. The gate drive circuit G21 is MO
Transistors TA21, TB21, TC which are SFET
21 is turned on and off. These transistors TA
21, TB21, TC21 are arranged so that the three-phase terminals U, V, W of the motor 12 and the ground of the battery 59 can be connected. Each transistor TA11, TB1
1, TC11, TA21, TB21, and TC21 are respectively connected with protective diodes D3 to D8. The voltage applied to the transistors TA11, TB11, TC11 is output as the voltage PIGM1. This voltage PI
When the difference between the GM1 and the boosted voltage value RV1 of the gate drive circuit G11 decreases to about 2V, the transistors TA11, TB11, TC11, TA21, TB which are MOSFETs.
On-resistance of the TC 21 and TC 21 may increase, which may cause abnormal heat generation. Therefore, when the difference between the voltage PIGM1 and the boosted voltage value RV1 of the gate drive circuit G11 becomes less than or equal to a predetermined value, all the transistors TA11, TB11, TC11,
It is preferable to turn off TA21, TB21, TC21. Incidentally, the transistor TA2 connected to the ground
Since a large current flows through the sources of 1, TB21 and TC21, it is preferable to wire the ground in a system different from the ground of the weak electric circuit section such as the microprocessor.

Next, the rotating operation of the motor 12 will be described with reference to FIG. 6 again. When 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 12 rotates. Clockwise rotation (C
W) 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 signal (LA11, LB
11, 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 42, the inner magnetic pole signals HA and H of the three Hall ICs are shown.
C is at high level. The direction of the winding current changes from U to V. At this time, the motor rotates and the magnet 42 rotates clockwise in the drawing. When the magnet 42 rotates 30 degrees, the magnetic pole signal HA switches from high level to low level. In accordance with this, the phase switching signals (LA11, LB11, LC1
1, LA21, LB21, LC21) = (H, L, L,
Switching to L, H, L) causes the motor to rotate continuously. In this way, in order to give a clockwise rotation (CW) or a counterclockwise rotation (CCW) to the motor,
The pattern of the phase switching signal may be switched according to the order of Table 1.

[0028]

[Table 1]

FIG. 9 shows the configuration of the microprocessor 1. The control of the microprocessor 1 is represented by a block diagram. The target rudder angle calculation unit 60, the motor servo control unit 61, the phase switching control unit 62, the magnetic pole sensor abnormality determination unit 63, the open control unit 64, the PWM signal generation unit 99 (hereinafter , PWM9
9) and a switch SW1.

Next, the function of the microprocessor 1 will be described. 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. The target steering angle calculation unit 60 sets the steering gain and the yaw rate gain according to the value of the vehicle speed V.
The steering gain and the steering angle θs are integrated,
While obtaining the steering control amount θ2, the yaw rate gain and the yaw rate γ are integrated to obtain the yaw rate control amount θ3.
Then, the anti-phase control amount θ1 is obtained from the steering angle θs. Then, in the built-in addition unit, the anti-phase control amount θ1, the steering control amount θ2, and the yaw rate control amount θ3 are added to obtain the target steering angle AGLA.

FIG. 10 shows a flowchart showing the operation of the magnetic pole sensor abnormality determination 63. Magnetic pole sensor signals HA, H
If any one of B and HC changes, the interrupt signal S1 changes and the magnetic pole sensor abnormality determination 63 is as shown in FIG.
Execute the interrupt routine as shown in. here,
Each time there is an interrupt, the time difference ΔT from the previous interrupt to the present interrupt is calculated (step 202), and the rotational speed of the motor 12 is calculated from the time difference ΔT and the coefficient K _T predetermined by the motor, The state of the magnetic pole sensor signal is determined and stored as the present value, and the present value stored so far is updated as the previous value.
That is, first, at step 203, the magnetic pole sensor signal H
The rotation speed N of the motor 12 is calculated based on the time difference between the edges of any of the signals A, HB, and HC. Then, in step 204, the magnetic pole sensor signals HA, HB, HC stored so far are updated as previous values. Next, at step 205, the states of the input terminals Ha, Hb, Hc of the magnetic pole sensor signals HA, HB, HC are read and stored as current values. Then, in step 206, the previous predicted value is read from the map shown in Table 2. As will be described later, the magnetic pole sensor 18 is configured so that any one of the magnetic pole sensor signals HA, HB, and HC sequentially changes. Therefore, one of the magnetic pole sensor signals HA, HB, and HC has changed with respect to the previous value and the current value.

In the previous predicted value of the map of Table 2, all possible states for the current value are stored. In particular,
When the current value is (HA, HB, HC) = (L, L, H), the previous predicted value is (H, L, H) or (L, H,
H). In step 207 of FIG. 10, this 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 matches the previous value, the abnormality flag Fabn is set to 0 in step 208. If the previous predicted value and the previous value do not match, step 209
Then, the abnormality flag Fabn is set to 1.

After that, the magnetic pole sensor signal edge interrupt routine is terminated. 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. In the present embodiment, whether or not the previous value is correct is determined by comparison from the present value, but the next value may be predicted from the present value and the comparison determination may be performed at the next signal input.

[0034]

[Table 2]

FIG. 11 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 direction of rotation is determined by whether the steering angle value HPID is positive or negative. If HPID> 0, direction flag DI = CCW,
If 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 (LA11, LB11, LC1
1, LA21, LB21, LC21) = (H, L, L,
L, H, L) and DI = CW (clockwise rotation)
If so, (H, L, L, L, L, H) is set as the next value. The set phase switching pattern is calculated in the first 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, when the steering angle value HPID is zero, the phase switching is set to the stop mode, and (LA11, LB11, LC11, LA2
1, LB21, LC21) = (L, L, L, L, L,
L) may be output.

[0037]

[Table 3]

[0038]

[Table 4]

FIG. 12 shows the open control unit 6 shown in FIG.
4 is a flowchart showing the operation of 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 execution flag Fopl 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 in progress flag Fopl
Is initially set to 0. In step 221, the state of the open control execution flag Fopl is judged, and if the open control execution flag Fopl 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, LA21, LB21, LC21) = (L, L, L, H, H, H), (LA12, LB12, LC12, LA22, LB22, LC22) = (L, L, L, H, H, H). When the predetermined time has passed, step 225
At, the open control execution flag Fopl is set to 1. 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 (LA11, LB11, LC11, LA21, LB21, LC21) = (H, L, L, L, H, L) and the rear wheel steering angle value θr is -1 degree. If there is, the next phase switching pattern will be (H, L, L, L, L, H).

The map shown in 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 equal to or less than the predetermined value A1, the phase switching pattern becomes (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 neutral return is performed.

[0041]

[Table 5]

FIG. 13 shows a functional block diagram of the inside of the motor servo control section 61. The motor servo control unit 61 is divided into a motor servo control function 61A and a current limiting function 61B, and FIG. 14 shows a control block diagram of the motor servo control function 61A. The differentiating unit 90 differentiates the target rudder angle value AGLA input from the target rudder angle calculation 60 to obtain a differential value SAGL.
Get A. The differential gain setting unit 91 obtains the differential gain YTDIFGAIN from the differential value SAGLA of the target steering angle value. 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,
When the absolute value of the differential value SAGLA is 12 deg / Sec or more, the differential gain is set to 4 and the differential value SAGLA
When the absolute value of is 4 to 12 deg / Sec, the differential gain becomes a value of 0 to 4. The rotation angle θm of the motor M1 is obtained from the output of the magnetic pole sensor 18. Although not shown, the motor rotation angle θm is determined by the output values HA, HB of the magnetic pole sensor 18,
It is obtained from HC 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. The rotation angle θm is given to the subtraction unit 92 as the actual steering angle value RAGL via the buffer 100. Subtraction unit 92
Subtracts the actual steering angle value RAGL from the target steering angle value AGLA,
Find 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 imparting unit 93 processes the steering angle deviation value ETH2 as 0 when the absolute value of the steering angle deviation ΔAGL is equal to or less than the predetermined value E2PMAX, and controls when the value of the steering angle deviation ΔAGL is small. Is to stop.

The obtained steering angle deviation value ETH2 is proportional to the proportional portion 96
And sent to the differentiator 94. The proportional portion 96 integrates the steering angle deviation value ETH2 by a predetermined proportional gain to obtain a proportional term PAG.
Get LA. Further, the differentiating unit 94 differentiates the steering angle deviation value ETH2 to obtain the steering angle deviation differential value SETH2. Steering angle deviation differential value SETH2 and differential gain YTDIFGAIN
And 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. The motor applied voltage instruction voltage Vc corresponding to the steering angle value is sent to the current limiting function 61B to limit the motor applied voltage for current limiting. The current limit function 61B checks whether the instruction voltage Vc exceeds the voltage limit value VL corresponding to the motor rotation speed N and the current limit value IL at that time, and if it exceeds the voltage command output Vout, From the instruction voltage Vc to the voltage limit value VL
Switch to. The voltage command output Vout is given to the PWM 99. The PWM 99 generates a pulse width modulation signal PWM1 having a pulse duty ratio Dr of VpsDr = Vout and supplies it to the motor driver 5. Note that Vps is a power supply voltage. The motor driver 5 uses the pulse width modulation signal PW
The motor 12 is rotationally biased (energized) according to M1. In this way, the motor 12 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 12 also changes according to the fluctuation of the power supply voltage Vps, the battery voltage is measured and the control amount AG
You may make it correct L.

FIG. 16 shows the processing contents of the current limiting function 61B. First, in step 300, the motor rotation speed N calculated in the magnetic pole sensor abnormality determination 63 is read from the memory, and based on the motor rotation speed N and the current limit value IL set in the memory, the current limit value IL is determined. The motor applied voltage limit value VL is calculated by the following equation.

VL = R · IL + K · N (1) Next, it is checked whether the motor applied voltage instruction voltage Vc calculated by the motor servo control function 61A is VL or more (step 302), and VL If less, the instruction voltage Vc is given to the PWM 99 as the voltage command output Vout (step 30
3) If it is VL or more, the voltage limit value VL is given to the PWM 99 as the voltage command output Vout (step 304).
In this way, the current I supplied to the motor 12 is constantly controlled by software processing so as not to exceed the limit value IL according to the rotation speed N thereof. As a result, the motor applied voltage Vout = R · I + K · N ≦ VL = R · IL + K · N
Then, R · I ≦ R · IL, that is, the motor current I ≦ current limit value IL.

[0046]

According to the present invention, for current limiting,
Conventionally required current detector body and drive it,
The sensing circuit for processing data is omitted,
It is possible to reduce the cost of the current limiting system and downsize the system. Not only the electric motor applied voltage upper limit signal
Since the motor current upper limit value can be changed by changing the current limit value (IL) which is given to or set in the means (61B) for calculating (VL), the current upper limit value can be set or changed. The degree of freedom is high, and it is easy to change the current limit value (IL) with the output of another control system.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a front and rear wheel steering system that incorporates an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view of a main part of the mechanism according to the embodiment of the present invention.

FIG. 3 is an enlarged sectional view taken along line 3A-3A in FIG.

4 is a cross-sectional view of the electric coil 44 of the motor shown in FIG. 3, taken along the line 6A-6A in FIG. 1 as viewed in the direction opposite to the arrow direction.

5 is an enlarged sectional view taken along line 6A-6A in FIG.

6 is a magnet 42 of the brushless motor 12 shown in FIG.
2 is a time chart showing the relationship between the rotation angle of the electric coil and the electric coil energization signal.

7 is a block diagram showing a configuration of an electronic control unit 9 shown in FIG.

8 is a block diagram showing an internal circuit of an EXOR circuit P3 shown in FIG. 7.

9 is a block diagram showing a functional configuration of the microprocessor 1 shown in FIG.

10 is a float chart showing the contents of the magnetic pole sensor abnormality determination 63 shown in FIG.

11 is a float chart showing the contents of the phase switching control 62 shown in FIG.

12 is a float chart showing the contents of the open control 64 shown in FIG.

13 is a block diagram showing a functional configuration of a motor servo control unit 61 shown in FIG.

FIG. 14 is a motor servo control function 61A shown in FIG.
3 is a block diagram showing the functional configuration of FIG.

FIG. 15 is a rotation speed N and a current limit value I of the motor 12.
It is a graph which shows the relationship between L and generated torque T.

FIG. 16 is a motor servo control function 61B shown in FIG.
3 is a float chart showing the processing contents of FIG.

17 is a block diagram showing a configuration of a driver 5 shown in FIG.

[Explanation of symbols]

1: Microprocessor 5: Motor driver 7: Relay 9: Electronic control device 10: Front wheel steering device 11: Rear wheel steering mechanism 12: Motor 13,14: Front wheel 15,16: Rear wheel 17,20: First and second Front wheel steering angle sensor 18: Magnetic pole sensor 19: Steering wheel 21: Rear wheel steering angle sensor 22, 23: First and second vehicle speed sensor 24: Yaw rate sensor 25: Operation axis 26: Male screw member 27: Rotation axis 28: Boot 42 : Magnet 43: Core 43a: Protrusion 44: Motor winding 44a, 44b, 44c, 44d, 44e, 44f: Winding 47: Holder 49: Substrate 50: Hall IC 53: Ball joint 55: Constant voltage regulator 57: Interface 59 : Battery 60: Target rudder angle calculation unit 61: Motor servo control unit 61A: Motor servo control function 61B: Current Limit function 62: Phase switching control unit 63: Magnetic pole sensor abnormality determination unit 64: Open control unit 79: Relay drive circuit 89: Pulse width modulation signal synthesis circuit 95: Accumulation unit 90, 94: Fractional unit 91: Fractional gain setting Part 92: Subtraction part 93: Deviation steering angle dead zone imparting part 96: Proportional part 97: Addition part 99: Pulse width modulation conversion part (PWM) 100: Buffer AGLA: Target rudder angle value D1-8: Diode DAGLA: Significant term E2PMAX: Predetermined value ETH2: Steering angle deviation value EXOR1, EXOR2: Exclusive OR circuit G11, G21: Gate drive circuit HA, HB, HC: Magnetic pole signal Vc: Steering angle value IGA: Power supply terminal IGSW: Ignition switch L1 phase switching Signal group LA11, LB11, LC11, LA21, LB21, LC21: Phase switching signal P3: EXOR circuit PAGLA: Proportional term PH: Pattern fuse PIGA: Power supply terminal PIGM1: Voltage PWM1: Pulse width modulation signal RAGL: Actual steering angle value S1: Interrupt data RV1: Rise Voltage value SAGLA: Derivative value SETH: Steering angle deviation descriptive value SW1: Switch TA11, TB11, TC11, TA21, TB21, TC21: Transistor TC: Choke coil U, V, W: Terminal V: Vehicle speed Vcc1: Constant voltage Vout : Control amount YTDIFGAIN: Contrast gain ΔAGL: Steering angle deviation γ: Yaw rate value θ1: Anti-phase control amount θ2, θ3: Steering control amount θm: Rotation angle θs: Steering angle

Claims (1)

[Claims] 1. A motor driver for energizing a winding of an electric motor; a server for generating an electric motor applied voltage instruction signal.
A voltage controller; a speed detecting means for detecting the rotation speed of the electric motor; a means for calculating an electric motor applied voltage upper limit signal corresponding to the rotation speed and the current limit value detected by the speed detecting means; An electric power supply control means for giving the motor driver the upper limit signal when the value represented by the upper limit signal exceeds the value represented by the upper limit signal, and the instruction signal when the value represented by the instruction signal is less than or equal to the value represented by the upper limit signal. Motor current control device.