JP4023299B2 - Motor control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a distributed motor control device.
[0002]
[Prior art]
Conventionally, the following distributed motor control devices are known. That is, as shown in FIG. 9, for example, the motor control device 100 of the electric power steering device includes a first MPU (Micro Processing Unit) 101 that calculates a motor command value based on the steering torque T, the vehicle speed V, and the like, And a second MPU 103 that drives the motor 102 based on the motor command value calculated by the first MPU 101. The port 101 a of the first MPU 101 and the port 103 a of the second MPU 103 are connected to each other by a parallel communication line 104. Since the motor command value is 8-bit data, the parallel communication line 104 includes eight data lines D0 to D7.
[0003]
Next, the operation of the conventional motor control apparatus configured as described above will be described with reference to the flowcharts shown in FIGS.
As shown in FIG. 10A, the first MPU 101 first reads sensor signals detected by various sensors. That is, the steering torque T detected by the torque sensor (not shown) and the vehicle speed V detected by the vehicle speed sensor (not shown) are read (S301). Next, the first MPU 101 calculates a motor command value (assist command current value) with reference to a characteristic map stored in advance based on the steering torque T and the vehicle speed V (S302). Then, the first MPU 101 sets the calculated motor command value in the port 101a and ends the process. The motor command value calculated by the first MPU 101 is sent to the second MPU 103 bit by bit through the data lines D0 to D7. Thereafter, the first MPU 101 repeats the processing of S301 to S303 every predetermined control cycle.
[0004]
On the other hand, in the second MPU 103, the following processing is performed. That is, as shown in FIG. 10B, the second MPU 103 first latches (holds) the motor command value sent from the first MPU 101 at the port 103a, that is, receives it (S401). Then, the second MPU 103 drives and controls the motor 102 based on the received motor command value (S402). Thereafter, the second MPU 103 repeats the processing of S401 and S402 every predetermined control cycle.
[0005]
[Problems to be solved by the invention]
However, the conventional motor control device has the following problems. In other words, distributed motor control devices used in electric power steering devices tend to be miniaturized, and along with this, various noises such as switching noise are generated in signals due to interference between the signal system and the power system. Becomes easier to overlap. When the motor command value calculated by the first MPU 101 is sent to the second MPU 103 via the 8-bit parallel communication line 104, the data is latched at the port 103a of the second MPU 103 when noise occurs. The second MPU 103 misrecognizes “0” as “1” or “1” as “0”. As a result of this bit error (so-called bit corruption), the second MPU 103 cannot receive a correct motor command value.
[0006]
When the motor command value calculated by the first MPU 101 is, for example, “+100”, this is expressed as “01100100 (B)” when expressed as a signed binary number. Here, the most significant bit is a sign bit indicating positive / negative (+, −), and the second and subsequent digits from the most significant are numerical bits indicating a numerical value. Incidentally, positive is indicated by “0” and negative is indicated by “1”. Each bit of the motor command value is sent to the second MPU 103 through eight data lines D0 to D7 of the parallel communication line 104, respectively.
[0007]
When the motor command value is transmitted, if any of the upper bits (for example, the upper 4 bits “0110”) is garbled in any of the numerical bits after the second digit, the second MPU 103 generates an error. The motor 102 is driven and controlled based on the recognized excessive motor command value.
[0008]
For example, if the motor command value calculated by the first MPU 101 is “+ 36 = 00100100 (B)” and the second digit from the most significant bit is garbled, the second MPU 103 sets the motor command value to “01100100 (B). "Is mistakenly recognized." This is +100 in decimal notation, which is an excessive value compared to the original motor command value “+36”.
[0009]
As shown in FIG. 11, for example, when noise is superimposed on the most significant bit signal of the motor command value and is latched by the second MPU 103 at this timing, the second MPU 103 sets the motor command value to 11100100 (B ) This is “−100” in decimal. That is, the second MPU 103 outputs a current command in the reverse direction to the original to the motor 102, and the motor 102 rotates in the reverse direction (rotates in the reverse assist direction) although it should be normally rotated in the normal direction.
[0010]
In this way, the higher-order bits have a larger number of digits, so the influence on the behavior of the motor 102 is greater. When the upper bits of the motor command value are garbled, the motor 102 is driven based on the excessive motor command value or the motor command value in the reverse direction as described above, and the motor 102 has an unintended behavior. There was a risk of showing.
[0011]
The present invention has been made to solve the above problems, and an object of the present invention is to provide a motor control device capable of suppressing unintended behavior of the motor.
[0012]
[Means for Solving the Problems]
The invention described in claim 1 includes a first MPU that calculates a motor command value, a second MPU that controls driving of the motor based on the motor command value calculated by the first MPU, and a first MPU. In the motor control device having a main parallel communication line connecting between the first MPU and the second MPU, a plurality of sub-lines different from the main parallel communication line are provided between the first MPU and the second MPU. A parallel communication line is provided, and the second MPU takes a majority decision for each bit between the motor command value sent by the main parallel communication line and the motor command value sent by each sub-parallel communication line. The gist is that the motor is driven and controlled based on the motor command value determined based on the above.
[0013]
According to a second aspect of the present invention, in the motor control device according to the first aspect, the main parallel communication line includes data lines for all bits of the motor command value, and each sub-parallel communication line is preset with the motor command value. The first MPU sends all the bits of the calculated motor command value to the second MPU through the main parallel communication line, and also sets the higher order multiple bits of the motor command value in advance. Is sent to the second MPU through each sub-parallel communication line.
[0014]
According to a third aspect of the present invention, in the motor control device according to the first or second aspect, the first MPU carries out the sub-parallel communication of the data obtained by carrying the calculated m-bit motor command value by n bits. The second MPU carries the data sent by each sub-parallel communication line by n bits, and sends the motor command value sent by the main parallel communication line to the second MPU. The majority (m−n) bits of the carry data are taken for each bit, and based on the result, the value of the upper (mn) bits of the motor command value is determined. Is the gist.
[0015]
According to a fourth aspect of the present invention, in the motor control device according to any one of the first to third aspects, the motor command value includes a motor current command value, a motor angular velocity command value, and a motor angle command value. The summary is at least one of the above.
[0016]
(Function)
According to the first aspect of the present invention, the motor command value calculated by the first MPU is sent to the second MPU through the main parallel communication line and the plurality of sub parallel communication lines. The second MPU takes a majority vote between the motor command value sent by the main parallel communication line and the motor command value sent by each sub parallel communication line for each bit, and the motor determined based on the result The motor is driven and controlled based on the command value. For this reason, the accuracy of the motor command value (data) is ensured.
[0017]
According to a second aspect of the present invention, in the motor control device according to the first aspect, all bits of the motor command value are sent to the second MPU through the main parallel communication line. Each of the sub-parallel communication lines sends the higher order multiple bits set in advance of the motor command value to the second MPU. The second MPU takes for each bit a majority decision between the motor command value sent by the main parallel communication line and the preset upper multiple bits of the motor command value sent by each sub parallel communication line. The motor is driven and controlled based on the motor command value determined based on the result. Therefore, the accuracy of at least the upper multiple bits of the motor command value (data) is ensured.
[0018]
According to the invention described in claim 3, in addition to the operation of the invention described in claim 1 or 2, the first MPU obtains data obtained by reducing the calculated m-bit motor command value by n bits. Each sub-parallel communication line is sent to the second MPU. The second MPU carries the data sent by each sub-parallel communication line by n bits. The second MPU takes a majority for each bit in the upper (mn) bits of the motor command value sent through the main parallel communication line and the carry-up data, and the motor command value is based on the result. The value of the upper (mn) bits is determined. For this reason, the accuracy of at least the upper (mn) bits of the motor command value (data) is ensured.
[0019]
According to the invention described in claim 4, in addition to the operation of the invention described in claim 1 or 2, the second MPU is a motor sent by the main parallel communication line and each sub communication line, respectively. The motor is driven and controlled based on at least one of the current command value, the motor angular velocity command value, and the motor angle command value.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment: EPS)
Hereinafter, a first embodiment in which the present invention is embodied in a motor control device of an electric power steering device will be described with reference to FIGS.
[0021]
(overall structure)
As shown in FIG. 1, the electric power steering device (EPS) 1 includes an electric power steering control device (hereinafter referred to as “control device 2”) and an electric motor 3 that is driven and controlled by the control device 2. A gear 4 is fixed to the output shaft of the electric motor 3. The electric motor 3 is a brushless motor constituted by a three-phase synchronous permanent magnet motor, and includes a motor rotation angle sensor (for example, a Hall element) 5. The motor rotation angle sensor 5 detects the rotation angle θm of the electric motor 3, that is, the electric angle indicating the magnetic pole position of the rotor constituting the electric motor 3, and sends the detection result (motor rotation angle signal) to the control device 2.
[0022]
On the other hand, a steering shaft 8 is connected to a steering wheel (hereinafter referred to as “handle 7”), and a reduction gear 9 is fixed to the steering shaft 8. The reduction gear 9 is engaged with the gear 4 of the electric motor 3. A torsion bar (torsion spring) 10 is incorporated in the steering shaft 8, and a torque sensor 11 is provided in the torsion bar 10. The torque sensor 11 detects the steering torque T acting on the handle 7 based on the twist amount of the torsion bar 10 when the steering wheel 7 is steered by the driver and the steering shaft 8 rotates. This steering torque signal is sent to the control device 2.
[0023]
A pinion gear 13 is fixed to the reduction gear 9 via a pinion shaft 12. The pinion gear 13 meshes with a rack 14, and tie rods 15 are fixed to both ends of the rack 14. A knuckle arm 16 is rotatably connected to the tip of the tie rod 15, and a cross member 17 is rotatably connected between the knuckle arms 16 and 16. A front wheel 18 is attached to each of the knuckle arms 16 and 16.
[0024]
A vehicle speed sensor 19 is provided for each of the front, rear, left and right wheels (in FIG. 1, only the vehicle speed sensor 19 of one front wheel 18 is shown). The vehicle speed sensor 19 detects the wheel speed (the number of rotations of the wheel per unit time, that is, the rotation speed), and sends the detection result (wheel speed signal) to the control device 2. The control device 2 calculates the vehicle speed V based on the wheel speed signal sent from the vehicle speed sensor 19.
[0025]
Now, when the steering wheel 7 is turned by the driver, the steering shaft 8 rotates. This rotation is transmitted to the rack 14 via the torsion bar 10, the pinion shaft 12 and the pinion gear 13, and is converted into the axial movement of the rack 14. Thereby, both front wheels 18 and 18 are steered.
[0026]
At this time, the control device 2 causes the electric motor 3 to generate a predetermined steering assist torque (assist torque) based on the steering torque T detected by the torque sensor 11 and the vehicle speed V detected by the vehicle speed sensor 19. Forward / reverse drive control. The rotation of the electric motor 3 is transmitted to the reduction gear 9 through the gear 4, and the number of rotations is reduced by the reduction gear 9 and transmitted to the pinion shaft 12 and the pinion gear 13. The rotation of the pinion gear 13 is transmitted to the rack 14 and converted into the axial movement of the rack 14. In this way, assist torque is applied to the steering of the front wheel 18 by the turning operation of the handle 7.
[0027]
(Control device)
Next, the electrical configuration of the control device 2 will be described.
As shown in FIG. 1, the control device 2 includes a first MPU (Micro Processing Unit) 21, a second MPU 22, a first ROM (read-only memory) 23, and a first RAM (read-write only memory) 24. , A second ROM 25, a second RAM 26, and a motor driving device 27. The control device 2 includes a current sensor 28.
[0028]
The first ROM 23 stores various control programs such as a basic assist control program and a handle return control program executed by the first MPU 21, various data, various characteristic maps, and the like. The various characteristic maps are obtained in advance by experimental data based on vehicle models and well-known theoretical calculations, for example, a basic assist torque map or vehicle speed for obtaining a basic assist current based on the vehicle speed V and the steering torque T, for example. There is a map for obtaining a steering wheel return command current based on the steering angular velocity and the steering absolute angle.
[0029]
The first RAM 24 is a data work area in which various control programs written in the first ROM 23 are expanded and the first MPU 21 executes various arithmetic processes. Further, the first RAM 24 temporarily stores various arithmetic processing results and the like when the first MPU 21 performs various arithmetic processes.
[0030]
A torque sensor 11 and a vehicle speed sensor 19 are connected to the first MPU 21 via input / output interfaces (not shown). The first MPU 21 executes various control programs such as a basic assist control program and a steering wheel return control program based on various information obtained from the torque sensor 11, the vehicle speed sensor 19, and the motor rotation angle sensor 5.
[0031]
The second ROM 25 stores various control programs such as a current control program and a PWM calculation program executed by the second MPU 22, various data, and the like.
[0032]
The second RAM 26 is a data work area in which various control programs written in the second MPU 22 are expanded and the second MPU 22 executes various arithmetic processes. Further, the second RAM 26 temporarily stores various arithmetic processing results and the like when the second MPU 22 performs various arithmetic processes.
[0033]
The motor rotation angle sensor 5 and the current sensor 28 are connected to the second MPU 22 via input / output interfaces (not shown). The second MPU 22 executes various control programs such as a current control program and a PWM calculation program based on the calculation result in the first MPU 21 and various information obtained from the motor rotation angle sensor 5 and the current sensor 28.
[0034]
(Motor drive device)
As shown in FIG. 2, the motor drive device 27 is configured by connecting a series circuit of FETs (field effect transistors) 31U and 32U, a series circuit of FETs 31V and 32V, and a series circuit of FETs 31W and 32W in parallel. It is configured. The connection point 33U between the FETs 31U and 32U is connected to the U-phase winding of the electric motor 3, the connection point 33V between the FETs 31V and 32V is connected to the V-phase winding of the electric motor 3, and the connection point 33W between the FETs 31W and 32W. Is connected to the W-phase winding of the electric motor 3.
[0035]
A booster circuit (not shown) is provided on a power supply line Lp between the motor drive device 27 and the battery 34 mounted on the vehicle, and the booster circuit receives a command signal from the second MPU 22 (boost circuit control). The voltage of the battery 34 is boosted based on the signal) and applied to each series circuit of the motor drive device 27.
[0036]
As shown in FIG. 2, the current sensor 28 includes a u-phase current sensor 28u and v-phase current sensors 28v and w for detecting three-phase excitation currents Iu, Iv, and Iw output from the motor drive device 27 to the electric motor 3, respectively. A phase current sensor 28w is provided. The u-phase current sensor 28u, the v-phase current sensor 28v, and the w-phase current sensor 28w send the detected u-phase excitation current Iu, v-phase excitation current Iv, and w-phase excitation current Iw to the second MPU 22, respectively.
[0037]
(Connection between the first and second MPUs)
As shown in FIG. 2, the first MPU 21 and the second MPU 22 are connected by a first parallel communication line Lc1, a second parallel communication line Lc2, and a third parallel communication line Lc3, respectively. The first parallel communication line Lc1 is a main communication line, and the second parallel communication line Lc2 and the third parallel communication line Lc3 are sub (sub) communication lines, respectively.
[0038]
The first parallel communication line Lc1 includes the same number of data lines as the bit length of the motor command value sent from the first MPU 21 to the second MPU 22. In this embodiment, the motor command value has a bit length of 8 bits, and the first parallel communication line Lc1 includes eight data lines Dm0 to Dm7. Each of the second parallel communication line Lc2 and the third parallel communication line Lc3 includes four data lines Ds0 to Ds3.
[0039]
The first MPU 21 includes a first port 41, a second port 42, and a third port 43. The second MPU 22 includes a first port 44, a second port 45, and a third port 46. Both the first ports 41 and 44 are 8-bit long parallel ports at bit positions b0 to b7, respectively. Both the second ports 42 and 45 and the third ports 43 and 46 are respectively at bit positions b0 to b3. This is a 4-bit parallel port.
[0040]
Between the first port 41 of the first MPU 21 and the first port 44 of the second MPU 22, more specifically, between the bit positions b0 to b7 of the first ports 41 and 44, respectively, the data lines Dm0 to Dm0. Connected by Dm7. Between the second port 42 of the first MPU 21 and the second port 45 of the second MPU 22, specifically, between the bit positions b0 to b3 of both the second ports 42 and 45, respectively, the data lines Ds0 to Ds0. Connected by Ds3. Between the third port 43 of the first MPU 21 and the third port 46 of the second MPU 22, specifically, between the bit positions b0 to b3 of the third ports 43 and 46, respectively, the data lines Ds0 to Ds0. Connected by Ds3.
[0041]
The first MPU 21 calculates a basic assist current value corresponding to the vehicle speed V and the steering torque T based on the basic assist torque map. Then, the first MPU 21 sends the calculation result (that is, the motor command value) to the second MPU 22 via the first parallel communication line Lc1, the second parallel communication line Lc2, and the third parallel communication line Lc3. Send to.
[0042]
The second MPU 22 is based on the rotation angle θm of the electric motor 3 detected by the motor rotation angle sensor 5, and the u-phase excitation current detected by the u-phase current sensor 28u, the v-phase current sensor 28v, and the w-phase current sensor 28w. The d-axis and q-axis currents are obtained by dq conversion of Iu, v-phase excitation current Iv, and w-phase excitation current Iw. Then, the second MPU 22 calculates a PI control value based on the basic assist current value sent from the first MPU 21 and the q-axis current.
[0043]
The second MPU 22 performs a PWM calculation according to the PI control value, and the result of the PWM calculation (motor control signal) is supplied to the motor drive device 27, specifically, FETs 31U and 32U, FETs 31V and 32V, FETs 31W and 32W. Respectively. The motor drive device 27 supplies the basic assist current (three-phase excitation current) to the electric motor 3 through the three-phase excitation current path on the basis of the sent PWM calculation result. The electric motor 3 applies a basic assist force to the handle 7 based on the supply of the basic assist current.
[0044]
(Operation of the embodiment)
Next, the operation of the electric power steering control device configured as described above will be described with reference to the flowcharts shown in FIGS. The flowchart shown in FIG. 3A is executed according to various control programs stored in advance in the first ROM 23. The flowchart shown in FIG. 3B is executed according to various control programs stored in advance in the second ROM 25. In this embodiment, “step” is abbreviated as “S”.
[0045]
(Operation of the first MPU)
As shown in FIG. 3A, the first MPU 21 first reads the sensor signal, that is, the steering torque T detected by the torque sensor 11 and the vehicle speed V detected by the vehicle speed sensor 19 (S101).
[0046]
Next, the first MPU 21 calculates an m-bit motor command value (assist command current value) based on the steering torque T and the vehicle speed V (S102). In the present embodiment, the motor command value is 8-bit (that is, m = 8) data. When the motor command value is “+100”, for example, this is expressed as “01100100 (B)” in a binary number with a sign. Incidentally, (B) is a symbol indicating that it is a binary number. The most significant bit is a sign bit, which indicates the sign of the motor command value, that is, “+”, “−”. When the sign bit is “0”, it indicates “+”, and when it is “1”, it indicates “−”. The second and subsequent digits from the most significant are numerical bits indicating numerical values.
[0047]
Next, the first MPU 21 sets all bits (8 bits) of the calculated motor command value in the first port 41 (S103). At this time, the bit positions b0 to b7 of the first port 41 correspond to the bit positions b0 to b7 of the first port 41 and the bit positions b0 to b7 of the first port 41, respectively, so that they correspond to each other. , 1, 0, 0, 1, 0, 0 are set.
[0048]
Next, the first MPU 21 sets a motor command value shifted to the right by n bits (digit reduction) (so-called motor command value with a digit loss) in the second port 42 of the first MPU 21 (S104).
[0049]
Here, n and m are both integers, and the relationship of shift number n <number of bits of motor command value m ”is established. In this embodiment, n = 4. That is, in the 8-bit motor command value, the upper 4 bits are each lowered by 4 digits. Specifically, the first MPU 21 sets the upper 4 digits “0110” in the motor command value “01100100 (B)” in the bit positions b0 to b3 of the second port 42, respectively.
[0050]
Next, the first MPU 21 sets the motor command value shifted to the right by n bits in the third port 43 of the first MPU 21 as in S104 (S105).
[0051]
The data structures of the motor command values set in the second port 42 and the third port 43 in the first MPU 21 are as shown in data B and data C shown in FIG. Then, the first MPU 21 transfers the data set in the first port 41, the second port 42, and the third port 43, respectively, to the first parallel communication line Lc1, the second parallel communication line Lc2, and the third port. Each is sent to the second MPU 22 by the parallel communication line Lc3.
[0052]
By the way, in binary numbers, every time one digit goes up, 2 ⁿ The data weight increases by n (n is the number of digits). That is, the higher bit affects the behavior of the electric motor 3. In the present embodiment, the upper 4 bits having a larger weight are preferentially sent to the second MPU 22. Thereafter, the first MPU 21 repeats the processing of S101 to S104 every predetermined control cycle.
[0053]
(Operation of the second MPU)
On the other hand, the following processing is performed in the second MPU 22. That is, as shown in FIG. 3B, the second MPU 22 first latches the motor command value sent from the first MPU 21 through the first parallel communication line Lc1 into the first port 44, that is, receives it. (S201). If noise is superimposed on data during communication and, for example, bit corruption occurs in the most significant bit (see FIG. 11), data A shown in FIG. That is, 1, 1, 1, 0, 0, 1, 0, 0 are held in the bit positions b0 to b7 of the first port 44, respectively. Incidentally, when there is no bit corruption, 0, 1, 1, 0, 0, 1, 0, 0 are held in the bit positions b0 to b7 of the first port 44, respectively.
[0054]
Next, the second MPU 22 uses the second port 45 for the motor command value (the motor command value with the digit dropped; the data shifted to the right by 4 bits) sent from the first MPU 21 through the second parallel communication line Lc2. (S202). When there is no garbled bit, the data B shown in FIG. Specifically, 0, 1, 1, 0 are held in the bit positions b0 to b3 of the second port 45, respectively.
[0055]
Next, the second MPU 22 latches, that is, receives, the motor command value sent from the first MPU 21 via the third parallel communication line Lc3 to the third port 46 (S203). When there is no bit corruption, the second port 45 holds the data C shown in FIG. Specifically, 0, 1, 1, 0 are held in the bit positions b0 to b3 of the third port 46, respectively.
[0056]
Next, the second MPU 22 has the same number of bits as the number of bits shifted to the right in S104 in the first MPU 21 by the motor command value (data B shown in FIG. 4) held in the second port 45. Shift left by 4 bits. (S204). That is, as shown in FIG. 4, the second MPU 22 raises each bit of the data “0110” held in the bit positions b3 to b0 of the second port 45 by 4 digits to obtain data Ba. The second MPU 22 recognizes the bit at the bit position having no numerical value (in this case, b0 to b3) as 0, and recognizes the motor command value sent through the second parallel communication line Lc2 as “01100000”.
[0057]
Further, the second MPU 22 has the same number of bits as the number of bits obtained by shifting the motor command value (data C shown in FIG. 4) held in the third port 46 to the right in S105 in the first MPU 21. Shift left by 4 bits. (S205). That is, as shown in FIG. 4, the second MPU 22 raises each bit of the data “0110” held in the bit positions b3 to b0 of the third port 46 by 4 digits to obtain data Ca. The second MPU 22 recognizes the bit at the bit position having no numerical value (in this case, b0 to b3) as 0, and recognizes the motor command value sent through the third parallel communication line Lc3 as “01100000”.
[0058]
Next, the second MPU 22 finally uses the motor command value to be adopted based on the data respectively sent by the first parallel communication line Lc1, the second parallel communication line Lc2, and the third parallel communication line Lc3. (S206). In the present embodiment, the majority (bit or bit) is taken for the upper (mn) bits of data A, Ba, and Ca, that is, the upper 4 bits, and the larger data (1 or 0) is adopted.
[0059]
For example, as shown in FIG. 4, in the data A, Ba, and Ca, the data held in the respective bit positions b7 are “1”, “0”, and “0”. That is, since there is one “1” and two “0” at the bit position b7, the second MPU 22 determines that “0” is positive and adopts it. Similarly, for the data at bit positions b7, b6, and b5, the second MPU 22 adopts “1”, “1”, and “0” as positive.
[0060]
For the remaining lower 4 bits, that is, data at bit positions b3, b2, b1, and b0, the second MPU 22 adopts the value of the data A sent through the first parallel communication line Lc1 as it is. Since the lower 4 bits have a smaller weight than the upper 4 bits, even if the bits are garbled, the behavior of the electric motor 3 is not significantly affected.
[0061]
The second MPU 22 configures the data D “01100100” shown in FIG. 4 by reflecting the result of the majority decision in S206 as the upper bits of the motor command value. This is the same value as the correct motor command value calculated by the first MPU 21. That is, even if the most significant bit of the motor command value sent from the first parallel communication line Lc1 is incorrect, the motor is obtained by taking the majority for each bit in the upper 4 bits of the data A, Ba, and Ca. Data errors in the upper 4 bits (the most significant bit in this embodiment) of the command value are corrected.
[0062]
Next, the second MPU 22 recognizes the data D, that is, “01100100” as a motor command value, and drives and controls the electric motor 3 based on the motor command value (S207). Although the most significant bit of the motor command value (data A in FIG. 4) sent from the first parallel communication line Lc1 has an error, the electric motor 3 is driven and controlled based on the normal motor command value. The
[0063]
As described above, the electric motor 3 is driven and controlled based on the excessive motor command or the current command in the direction opposite to the original command due to the garbled bits of the higher-order bits (4 bits in this embodiment). It is avoided. As a result, the unintended behavior of the electric motor 3 is suppressed.
[0064]
(Effect of embodiment)
Therefore, according to the present embodiment, the following effects can be obtained.
(1) In addition to the first parallel communication line Lc1 that sends the motor command value calculated by the first MPU 21 to the second MPU 22, the second parallel communication line Lc2 that also sends the motor command value to the second MPU 22 And a third parallel communication line Lc3. Then, the second MPU 22 bit by bit between the motor command value sent via the first parallel communication line Lc1 and the motor command value sent via the second and third parallel communication lines Lc2 and Lc3. The majority vote was taken. The second MPU 22 controls the drive of the motor based on the motor command value determined based on the majority result. For this reason, even if there is an error in the motor command value sent through the first parallel communication line Lc1, this error is different from the motor command value sent through the second and third parallel communication lines Lc2 and Lc3. It is corrected by taking a majority vote for each bit. Therefore, even if there is an error in the motor command value sent through the first parallel communication line Lc1, the drive control can be continued without stopping the electric motor 3. As a result, the accuracy of the motor command value is ensured, and the unintended behavior of the electric motor 3 can be suppressed.
[0065]
(2) The first parallel communication line Lc1 includes data lines Dm0 to Dm7 corresponding to the total number of bits (8 bits) of the motor command value. The second and third parallel communication lines Lc2 and Lc3 are each provided with a data line for a plurality of bits (4 bits) set in advance for the motor command value. The first MPU 21 sends all the bits of the motor command value to the second MPU 22 via the first parallel communication line Lc1. Further, the first MPU 21 is configured to send the upper multiple bits (upper 4 bits) set in advance of the motor command value to the second MPU 22 through the second and third parallel communication lines Lc2 and Lc3, respectively. For this reason, it is possible to ensure the accuracy of at least the higher-order multiple bits of the motor command value sent through the first parallel communication line Lc1. Therefore, it is possible to avoid the drive control of the electric motor 3 based on the excessive command or the reverse rotation command caused by the garbled bits of the higher-order bits, and the unintended behavior of the electric motor 3 can be suppressed.
[0066]
(3) The first MPU 21 uses the second and third parallel communication lines Lc2 and Lc3 to generate data obtained by reducing the calculated m-bit (8-bit) motor command value by n bits (4 bits). I sent it to MPU22. Further, the second MPU 22 carries the data sent through the second and third parallel communication lines Lc2 and Lc3 by n bits. Then, the second MPU 22 takes the majority for each bit in the upper (mn) bits, that is, 4 bits, of the motor command value sent by the first parallel communication line Lc1 and the carried data. Based on this result, the upper 4 bits of the motor command value are determined. For this reason, it is possible to correct an error of at least the upper 4 bits of the motor command value sent through the first parallel communication line Lc1.
[0067]
(4) The number of data lines of the second and third parallel communication lines Lc2 and Lc3 is made smaller than the number of data lines of the first parallel communication line Lc1. For this reason, the product of the control device 2 is compared with the case where the number of data lines of the second and third parallel communication lines Lc2 and Lc3 is the same as the number of data lines of the first parallel communication line Lc1. Cost can be reduced. Further, the ports (bit positions) of the first ports 41 and 44, the second ports 42 and 45, and the third ports 43 and 46 can be saved.
[0068]
(5) The number of communication lines between the first MPU 21 and the second MPU 22 is an odd number (three in this embodiment). For this reason, when a majority decision is taken for each bit in the motor command values sent by the first to third parallel communication lines Lc1 to Lc3, it always becomes “1” or “0”. Therefore, the second MPU 22 always obtains a majority result. Incidentally, when the number of communication lines is an even number (for example, 4 lines), a majority decision cannot be made when two “1” s and two “0” s are recognized in a certain bit.
[0069]
(6) A motor current command value (specifically, a basic assist current value) is used as the motor command value. Therefore, the control device 2 can be applied to a system that similarly controls the current of the motor.
[0070]
(Second embodiment; VGRS)
Next, a second embodiment in which the present invention is embodied in a variable gear ratio steering system (VGRS) will be described. This embodiment is different from the first embodiment in that the object to be controlled is not the electric motor of the electric power steering apparatus but the electric motor of the variable gear ratio steering system. Therefore, the same member configuration as that of the first embodiment is denoted by the same reference numeral, and redundant description thereof is omitted.
[0071]
As shown in FIG. 5, one end of a first steering shaft 53 is connected to a steering wheel (hereinafter referred to as a handle 52) of the gear ratio variable steering system 51, and the other end of the first steering shaft 53 is connected. Is connected to the input side of the gear ratio variable unit 54. One end of the second steering shaft 55 is connected to the output side of the gear ratio variable unit 54, and the other end of the second steering shaft 55 is connected to the input side of the steering gear box 56. The steering gear box 56 includes a pinion gear (not shown), and the pinion gear meshes with the rack shaft 57. The rotational motion input to the second steering shaft 55 is transmitted to the rack shaft 57 via the pinion gear, and converted into the axial motion of the rack shaft 57.
[0072]
The variable gear ratio unit 54 includes a reduction gear 58 that operatively connects the first steering shaft 53 and the second steering shaft 55, an electric motor 59 that drives the reduction gear 58, and the like. By driving the electric motor 59, the transmission ratio (steering gear ratio) between the first steering shaft 53 and the second steering shaft 55 changes via the speed reducer 58. Incidentally, the steering gear ratio is the ratio of the total rotation angle of the handle 7 (from lock to lock) and the turning angle of the wheel (steered wheel) in the rack and pinion type electric power steering apparatus 1 in this embodiment. Say.
[0073]
As shown in FIG. 6, the variable gear ratio steering system 51 includes a steering angle sensor 61 that detects a rotation angle (that is, a steering angle θh) of the first steering shaft 53 and a rotation angle (that is, an output) of the second steering shaft 55. An output angle sensor 62 for detecting the angle θp) is provided. The gear ratio variable steering system 51 includes a vehicle speed sensor 63 that detects the vehicle speed V and a rotation angle sensor 64 that detects the rotation angle (electrical angle) of the electric motor 59.
[0074]
The steering angle θh detected by the steering angle sensor 61, the output angle θp detected by the output angle sensor 62, the vehicle speed V detected by the vehicle speed sensor 63, and the rotation angle θm of the electric motor 59 detected by the rotation angle sensor 64 are: Each is sent to the control device 65 of the variable gear ratio steering system 51. The control device 65 drives and controls the electric motor 59 based on the steering angle θh, the output angle θp, the vehicle speed V, and the rotation angle θm.
[0075]
That is, the first MPU 21 of the control device 65 refers to the motor rotation angle characteristic map (not shown) stored in advance in the first ROM 23 (see FIG. 1) based on the steering angle θh and the vehicle speed V. The motor rotation angle command value (motor angle command value) of the electric motor 59 in the variable ratio unit 54 is calculated. The motor rotation angle characteristic map shows the change in the motor rotation angle command value with respect to the increase in the vehicle speed V. The motor rotation angle command value is uniquely determined according to the vehicle speed V.
[0076]
The first MPU 21 sends all bits (8 bits) of the calculated motor rotation angle command value to the second MPU 22 through the first parallel communication line Lc1. Further, the first MPU 21 sends the upper 4 bits of the motor rotation angle command value to the second MPU 22 through the second and third parallel communication lines Lc2 and Lc3 (see the flowchart of FIG. 3A).
[0077]
The second MPU 22 sends the motor rotation angle command value sent via the first parallel communication line Lc1, the motor rotation angle command value sent via the second parallel communication line Lc2, and the third parallel communication line Lc3. The majority of each bit is taken for the upper 4 bits of the motor rotation angle command value. Then, the second MPU 22 determines that the larger value is positive and adopts it, and determines the final motor command value. Based on this motor command value, the second MPU 22 drives and controls the electric motor 59 (see the flowchart in FIG. 3B).
[0078]
At this time, the rotation angle θm of the electric motor 59 detected by the rotation angle sensor 64 is fed back to the second MPU 22. Then, the second MPU 22 feedback-controls the motor current so that the motor rotation angle command value calculated by the first MPU 21 matches the actual rotation angle θm of the electric motor 59.
[0079]
By setting the transmission ratio (steering gear ratio) according to the vehicle speed V, the handling performance of the handle 7 is improved. For example, the steering gear ratio is set so that the output angle θp of the gear ratio variable unit 54 is larger than the steering angle θh of the handle 7 when the vehicle is stopped or traveling at a low speed. As a result, it is possible to turn with fewer handle operations. In addition, the steering gear ratio is set so that the output angle θp of the gear ratio variable unit 54 is smaller than the steering angle θh of the handle 7 during high speed traveling. As a result, a calm and stable vehicle response is realized.
[0080]
Therefore, according to the present embodiment, in the system in which the motor angle command value (specifically, the motor rotation angle command value) is used as the motor command value, (1) to (5) of the first embodiment. The same effect as the) th can be obtained. Further, the control device 65 can be applied to other systems for controlling the angle of the motor (position control).
[0081]
(Third embodiment: NC machine tool)
Next, a third embodiment in which the present invention is embodied in an NC machine tool will be described. This embodiment is different from the first embodiment in that the object to be controlled is not the electric motor of the electric power steering device but the electric motor for table feed of the NC machine tool. Therefore, the same member configuration as that of the first embodiment is denoted by the same reference numeral, and redundant description thereof is omitted.
[0082]
As shown in FIG. 7, a ball screw 73 is rotatably supported on a fixed table 72 of an NC machine tool 71 via a bearing (not shown), and an outer end portion of the ball screw 73 is an electric motor for feeding. It is connected to 74 output shafts via a coupling (not shown). A nut 75 is screwed onto the ball screw 73. The nut 75 can be screwed and unscrewed as the ball screw 73 rotates forward and backward. A headstock 77 is provided on the upper surface of the nut 75 via a moving table 76 so as to be movable together. A main shaft motor 78 is fixed to the main shaft base 77, and a main shaft 79 is operatively connected to the output shaft of the main shaft motor 78. A tool 80 such as a tap is attached to the tip of the main shaft 79.
[0083]
Therefore, when the feed electric motor 74 is driven, the nut 75 is reciprocated along the axis of the ball screw 73 by the rotation of the ball screw 73, and the moving table 76 is also moved along the ball screw 73 along with this ( It reciprocates in the direction of the arrow shown in FIG. When the spindle motor 78 is driven, the tool 80 rotates forward and backward together with the spindle 79.
[0084]
The NC machine tool 71 includes a feed motor rotation angle sensor 81 that detects the rotation angle θms of the feed electric motor 74 and a spindle motor rotation angle sensor 82 that detects the rotation angle θmp of the spindle motor 78. The rotation angle θms and the rotation angle θmp detected by the feed motor rotation angle sensor 81 and the spindle motor rotation angle sensor 82 are sent to the control device 91 of the NC machine tool 71, respectively.
[0085]
As shown in FIG. 8, the control device 91 includes a first MPU 21, a second MPU 22, a feed motor drive device 92, a spindle motor drive device 93, and a PLO (programmable logic control device) 94. The PLO 94 is connected to the first MPU 21. An input / output device (operation panel) 95 is connected to the PLO 94. The PLO 94 has a sequencer function, and determines and selects an NC program to be executed by the first MPU 21 and causes the first MPU 21 to execute the NC program according to a predetermined program command.
[0086]
That is, the first MPU 21 receives a motor command value for the feed electric motor 74 (motor angle command value; feed amount of the moving table 76) and a spindle motor based on a predetermined program command from the PLO 94 every predetermined control cycle. The motor command value for 78 (motor angular velocity command value; rotational angular velocity of the spindle 79) is calculated.
[0087]
The first MPU 21 sends all bits (8 bits) of the calculated motor angle command value and motor angular velocity command value to the second MPU 22 via the first parallel communication line Lc1. Further, the first MPU 21 sends the upper 4 bits of the motor angle command value and the motor angular velocity command value to the second MPU 22 via the second and third parallel communication lines Lc2 and Lc3 (in FIG. 3A). (Refer to the flowchart).
[0088]
The second MPU 22 takes a majority for each bit with respect to the upper 4 bits of the motor angle command value and the motor angular velocity command value sent through the first to third parallel communication lines Lc1 to Lc3. Then, the second MPU 22 determines that the larger value is positive and adopts it, and determines the final motor command value (motor angle command value and motor angular velocity command value). Based on this motor command value, the second MPU 22 drives and controls the electric motor 59 (see the flowchart in FIG. 3B).
[0089]
At this time, the rotation angle θms detected by the feed motor rotation angle sensor 81 and the rotation angle θmp detected by the spindle motor rotation angle sensor 82 are fed back to the second MPU 22, respectively. The second MPU 22 performs feedback control on the motor currents of the feed electric motor 74 and the spindle motor 78 based on the rotation angles θms and θmp, respectively. That is, the second MPU 22 includes the feed electric motor 74 and the main shaft so that the motor command values (motor angle command value and motor angular velocity command value) and the actual motor rotation angles (electrical angles) θms and θmp are respectively matched. The motors 78 are driven and controlled.
[0090]
Therefore, according to the present embodiment, in the system in which the motor angle command value and the motor angular velocity command value are used as the motor command value, the same effects as the (1) to (5) th of the first embodiment are obtained. Obtainable. The control device 91 can also be applied to other systems that control the speed (angular speed) of the motor.
[0091]
(Another example)
In addition, you may implement this embodiment by changing into the following another examples.
In the first to third embodiments, the first MPU 21 and the second MPU 22 are provided in the same control device 2, 65, 91, respectively. For example, the first MPU 21 is provided in the control devices 2, 65, 91. You may make it provide outside. In this way, the control devices 2, 65, 91 can be downsized.
[0092]
In the first and second embodiments, the function of the first MPU 21 may be performed by the MPU of a system other than the electric power steering device 1 and the variable gear ratio steering system 51. For example, in a vehicle system in which the electric power steering device 1, the gear ratio variable steering system 51 and SC (stability control; stability control) and the like are combined and controlled, an integrated control ECU (integrated control ECU ( The motor command value is calculated by an electronic control unit). Then, this calculation result is sent to the second MPU 22 by, for example, CAN (Controller Area Network) communication (ie, in-vehicle LAN). Motor current control is performed based on the calculation result (motor command value), and drive control of the electric motor 3 of the electric power steering apparatus 1 and the electric motor 59 of the gear ratio variable steering system 51 is performed. In this way, the control devices 2 and 65 can be downsized.
[0093]
In the first to third embodiments, the upper 4 bits of the motor command value calculated by the first MPU 21 are sent to the second MPU 22 through the second and third parallel communication lines Lc2 and Lc3, respectively. At least the upper 2 bits may be sent. That is, in S104 and S105 in the flowchart shown in FIG. 3A, the value of the motor command value shift number n is set to at least “6”. In this way, it is possible to avoid the drive control of the electric motor 3 while at least the forward / reverse current command value and the most weighted numerical value are incorrect.
[0094]
In the first to third embodiments, there is a relationship of “m> n” between the total number of bits m of the motor command value and the shift number n of the motor command value in S104 and S105 (see FIG. 3A). The value of “n” may be arbitrarily changed within the range in which In this case, (mn) bits are reserved for the second ports 42 and 45 and the third ports 43 and 46, respectively, and the second and third parallel communication lines Lc2 and Lc3 are respectively ( mn) comprises data lines. In the first to third embodiments, it is desirable to send all the bits of the motor command value also in the second and third parallel communication lines Lc2 and Lc3. When all the bits of the motor command value are sent, n = 0. For example, when the motor command value shift number n is any one of 0 to 3, the accuracy of the motor command value can be made more factory.
[0095]
In the first to third embodiments, a parity check may be performed for each data transmitted through the first to third parallel communication lines Lc1 to Lc3. That is, the first MPU 21 transfers data with 1 (or 0) number of even / odd numbers (parity bits) included in the motor command value (8 bits). The second MPU 22 compares the attached parity bit with the number of 1 (or 0) included in the data, and determines that there is an error in the data if even / odd does not match. In this way, even if bit corruption occurs in all of the data (data A, B, and C in FIG. 4) respectively sent through the first to third parallel communication lines Lc1 to Lc3, an error in data occurs. Can be detected.
[0096]
In the first to third embodiments, a checksum (check sum) may be performed for each data transmitted through the first to third parallel communication lines Lc1 to Lc3. That is, the first MPU 21 calculates the total value (check sum) of the motor command value (8 bits), and sends the data with the calculated value. The second MPU 22 similarly calculates a checksum from the transmitted data string, and checks whether it matches the checksum transmitted from the first MPU 21. If they are different, the second MPU 22 determines that an error has occurred in the data on the communication path. In this way, even if bit corruption occurs in all of the data (data A, B, and C in FIG. 4) respectively sent through the first to third parallel communication lines Lc1 to Lc3, an error in data occurs. Can be detected.
[0097]
In the present embodiment, each of the first MPU 21 and the second MPU 22 is an 8-bit system, but may be a system having an arbitrary number of bits, such as a 16-bit system.
[0098]
(Appendix)
Next, a technical idea that can be grasped from the embodiment and another example will be added below.
(A) The motor control device according to any one of claims 1 to 3, wherein the sub-parallel communication line is an odd number.
[0099]
(B) A motor that is provided in a vehicle steering system so as to be able to transmit torque and generates steering assist torque, a motor drive unit that drives the motor, and energization control of the motor drive unit to control the drive of the motor. The electric power steering apparatus provided with the motor control apparatus, The electric power steering apparatus provided with the motor control apparatus as described in any one of Claims 1-3.
[0100]
(C) A gear ratio variable steering system including a variable gear ratio unit that changes a transmission ratio between the steering angle of the steering wheel and the steered wheel, and steering for detecting the steering angle of the steering wheel. An angle sensor; a vehicle speed sensor that detects a vehicle speed; an electric motor that drives the gear ratio variable unit; and a steering angle that is set by the steering angle sensor and sets the transmission ratio based on the vehicle speed detected by the vehicle speed sensor. A variable gear ratio steering system comprising a control means for controlling the drive of the electric motor on the basis of a gear ratio variable steering system comprising the motor control device according to any one of claims 1 to 4. .
[0101]
(D) In a data transmission method in which data calculated by the first MPU is sent to the second MPU through the main parallel communication line, the main parallel communication line is between the first MPU and the second MPU. A plurality of sub parallel communication lines are provided, and the second MPU determines a majority for each bit between the motor command value sent by the main parallel communication line and the motor command value sent by each sub parallel communication line. Thus, a data transmission method for correcting an error in data sent through the main parallel communication line.
[0102]
(E) The first MPU sends a plurality of preset bits of the calculated data to the second MPU via each sub-parallel communication line, and the second MPU is sent via the main parallel communication line. The data transmission method according to the above item (d), wherein a majority vote is taken for each bit of the data and the higher order multiple bits sent by each sub-parallel communication line.
[0103]
【The invention's effect】
According to the present invention, an unintended behavior of the motor can be suppressed by correcting an error in the motor command value.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an electric power steering apparatus according to a first embodiment.
FIG. 2 is a circuit diagram of a motor control device according to the first embodiment.
FIG. 3A is a flowchart showing processing at the time of data transmission of the first MPU in the first embodiment;
FIG. 6B is a flowchart showing processing at the time of data reception of the second MPU in the first embodiment.
FIG. 4 is a data configuration diagram showing a configuration of data latched in a first port and a second port of a second MPU in the first embodiment, respectively.
FIG. 5 is a schematic configuration diagram of a gear ratio variable steering system according to a second embodiment.
FIG. 6 is a circuit diagram of a motor control device according to a second embodiment.
FIG. 7 is a schematic configuration diagram of an NC machine tool according to a third embodiment.
FIG. 8 is a circuit diagram of a motor control device according to a third embodiment.
FIG. 9 is a circuit diagram of a conventional motor control device.
FIG. 10A is a flowchart showing processing at the time of data transmission of a conventional first MPU;
(B) is a flowchart showing processing at the time of data reception of a conventional second MPU.
FIG. 11 is a timing chart illustrating a situation where data is garbled.
[Explanation of symbols]
3, 59, 74, 78 ... electric motor,
2, 65, 91 ... a control device constituting a motor control device,
21. First MPU,
22 ... second MPU,
A, B, Ba, C, Ca, D ... data,
Dm0 to Dm7: Data line of the first parallel communication line,
Ds0 to Ds3 ... data lines of the second and third parallel communication lines,
Lc1 ... a first parallel communication line constituting a main parallel communication line,
Lc2 ... a second parallel communication line constituting a sub-parallel communication line,
Lc2 ... a third parallel communication line constituting a sub-parallel communication line,
m: Number of bits of motor command value,
n: Number of shifts.

Claims (4)

Between the first MPU that calculates the motor command value, the second MPU that drives and controls the motor based on the motor command value calculated by the first MPU, and the first MPU and the second MPU. In a motor control device having a main parallel communication line to be connected,
A plurality of sub parallel communication lines different from the main parallel communication line are provided between the first MPU and the second MPU,
The second MPU takes a majority for each bit of the motor command value sent by the main parallel communication line and the motor command value sent by each sub parallel communication line, and is determined based on this result. A motor control device that drives and controls a motor based on a motor command value. The main parallel communication line has a data line for all bits of the motor command value,
Each sub-parallel communication line has a data line for a plurality of bits set in advance for the motor command value,
The first MPU sends all the bits of the calculated motor command value to the second MPU via the main parallel communication line, and similarly, the upper plurality of bits set in advance of the motor command value are respectively sent to the second MPU via the sub parallel communication lines. The motor control device according to claim 1, wherein the motor control device is sent to the MPU. The first MPU sends data obtained by reducing the calculated m-bit motor command value by n bits to the second MPU via each sub-parallel communication line,
The second MPU carries the data sent by each secondary parallel communication line by n bits,
The majority (m−n) bits of the motor command value sent by the main parallel communication line and the carry-up data are taken for each bit, and based on the result, the upper (m 3. The motor control device according to claim 1, wherein the value of the bit is determined. The motor control device according to any one of claims 1 to 3, wherein the motor command value is at least one of a motor current command value, a motor angular velocity command value, and a motor angle command value.

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