JPH08205570A - Motor controller - Google Patents

Abstract

PURPOSE: To make it possible to control smoothly without changing hardware even if a motor is different by constituting gain data and current control parameter data being writable and readable with respect to the memory sent from a communication interface in the central processing unit. CONSTITUTION: When a communication interface 72 receives gain data of variable gain amplifier input from the outside and current control parameter data of a motor controller, said interface transmits these data to a central processing unit 77. This central processing unit 77 constitutes the gain data sent from the communication interface 72 and current control parameter data being writable and readable with respect to the memory. And new data are read out from the memory of the central processing unit 77 and a servo motor is controlled based on said data. By doing this, smooth control is possible without changing hardware even through the motor has been changed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor control device for driving and controlling a servo motor, and more particularly to a motor control device capable of externally changing the gain of a drive current detecting means and the current control parameter of the motor control device. .

[0002]

2. Description of the Related Art In numerical control devices and positioning devices for controlling industrial robots, machine tools or automation devices,
An AC servomotor is used to position each rotary shaft. The servo motor is controlled by a multi-axis motor control device incorporating a servo control system.

FIG. 15 shows an example of the configuration of a control unit per axis in a conventional multi-axis motor control device. FIG.
At, the rotational position target value Pref of the servomotor M1 is input via the control signal connector 205 and input to the position control unit 260. The position control unit 260 compares the position detection value converted from the encoder signal e1 fed back from the encoder E1 with the rotational position target value Pref, and uses the difference value as the speed command s, the speed control unit 261.
Send to The speed control unit 261 compares the speed detection value Sdet with the speed command s, and sends the difference value to the current control unit 262 as the current command i. The current controller 262 uses the magnetic pole position signal of the servomotor M1 obtained from the encoder signal e1, the current command i, the A / D converter 253, and the current detector 258.
A three-phase voltage command v is generated based on the detected current value Idet fed back from the output signal and output to the PWM signal generation unit 263. The PWM signal generator 263 has a three-phase voltage command v
The PWM signal is generated based on the
It sends to the inverter 252 via 51. Inverter 25
2 generates a drive voltage according to the input PWM signal and drives the servomotor M1.

The current detector 258 constitutes a feedback loop for monitoring the drive current of the inverter 252 and performing feedback control, and the output signal thereof is A / D converted by the A / D converter 253.

The position control unit 260 and the speed control unit 261 described above.
Although not shown, the current controller 262 is executed by a control program stored in a CPU (central processing unit) and a ROM (read-only memory) incorporated in the control unit U1. As the ROM, a one-time ROM, a mask ROM, or the like is used, but in any case, the control program once written cannot be rewritten.

In order to maximize the resolution of the A / D converter 253, it is necessary to match the maximum current allowed in the servomotors M1 to M6 with the input dynamic range of the A / D converter 253. A / D converter 2 according to the maximum current value of the servomotors M1 to M6 to be controlled
It is necessary to change the gain of the current detector 258 located in the preceding stage of 53.

Further, in the servo motors M1 to M6, the maximum current is limited due to the demagnetization of the field (permanent magnet).
It is necessary to change the drive current limit value by the torque command limiter for each of the servo motors M1 to M6.

As a publicly known technique relating to this type of motor control device, there is JP-A-4-340387.

[0009]

The problem of the above-mentioned conventional motor control device is that the conventional motor control device cannot be used when the servo motor is changed, and the degree of freedom in application is lacking. It is a point. That is, as described above, the conventional motor control device determines the control constant in accordance with the rating or constant of the servo motor to be applied, and stores the control program based on the control constant in ROM.

As a result, even if the servo motors have the same constant, there is no compatibility between the old and new models, and a new motor control device has to be constructed. Also, for example,
When this motor control device is used for a robot, it is not versatile for a plurality of types of robots having different specifications, and it is necessary to manufacture a motor control device suitable for each robot.

An object of the present invention is to provide a motor control device having general versatility that enables smooth control without changing the hardware even when the motor is different.

[0012]

In order to solve the above problems, the present invention provides a motor drive means for converting a DC power into an AC power to supply a drive current to a servo motor, and a detection signal of the drive current. A current that has a variable gain amplifier that amplifies according to the characteristics of the servo motor to be controlled, and an A / D converter that converts the amplified current detection signal into a digital signal, and feeds back the current detection signal to the motor drive means. In a motor control device including a detection means, a central processing unit that controls the motor control device, gain data of the variable gain amplifier and current control parameter data of the motor control device that are input from the outside are received, and A communication interface capable of transmitting to a central processing unit, gain data of the variable gain amplifier, and a current control parameter. And a memory for storing electrically rewritable in the metadata, and the gain data and current control parameter data transmitted to the central processing unit from the communication interface and configured to write and read to the memory.

[0013]

According to the invention described in claim 1, when the communication interface receives the gain data of the variable gain amplifier and the current control parameter data of the motor control device which are input from the outside, the communication interface receives the data. Send to. The central processing unit writes the gain data and the current control parameter data sent from the communication interface in the memory. The memory is electrically rewritable and stores new data in place of the gain data and the current control parameter data that have been stored until then. The central processing unit controls the servo motor based on the new gain data and current control parameter data. Therefore, various servo motors can be supported by setting and inputting desired gain data and current control parameter data through the communication interface when the servo motor is changed, and it is troublesome to replace the ROM and the economical burden associated with the replacement. Is greatly reduced, and versatility as a motor control device is secured.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, preferred embodiments of the present invention will be described with reference to the drawings. (I) Assembly Structure of Each Functional Element Unit of Multi-Axis Motor Control Device FIG. 1 shows an example of an assembly structure of each functional element unit of the multi-axis motor control device according to the present invention. As shown in FIG.
A backplane 1 made of BS resin or the like is provided in the vertical direction, and a plurality of functional element units are separated and arranged in two rows on the front surface side of the backplane 1 and fixed in an array. The upper row is arranged in a state in which the main circuit power supply unit 2, the additional capacitor units 3 and 4, and the small signal power supply unit 5 are gathered, and the lower row is the biaxial inverter unit 6,
7, 8 and the lower control unit (for 6 axes) 9 and the upper control unit 10 are arranged in a state of being assembled.

A printed wiring layer is formed in advance on the back surface side (back surface side if necessary) of the backplane 1, and this printed wiring circuit has a circuit pattern necessary for constructing the multi-axis motor control device. Is formed by.

A power supply connector 12 is provided on the surface of the backplane 1 adjacent to the functional unit groups 6 to 10. A power supply cable from a commercial power supply 11 is connected to the power supply connector 12. To be done. Power line connectors 13, 14, and 15 are provided below the lower functional element unit groups 6 to 10 on one surface. These power line connectors 13, 14, 15 are
Motor wiring 16 to each servo motor M1 to M6
21 is connected. An encoder connector 23 and a serial communication connector 24 are provided on the lower surface of the lower control unit 9.
Is provided. One end of the encoder signal line 22 for six axes is connected to the encoder connector 23, and an external setting device 26 such as a personal computer or a control parameter setting unit is connected to the serial communication connector 24 via a communication line 25. . By providing the encoder connector 23 and the serial communication connector 24 not on the backplane 1 but on the lower surface side of the lower control unit 9, reduction of the number of wires of the lower control unit 9 and the connecting connectors 37, 41 of the backplane 1 is promoted. To be done. Similarly, a serial communication connector 27 is provided on the lower surface of the host control unit 10, and an external setting device 29 such as a personal computer or a teaching pendant is connected to the serial communication connector 27 via a communication line 28.

FIG. 2 shows a detailed example of the assembly structure of each of the functional element units. As shown in FIG. 2, on the front surface side of the backplane 1, the backplane 1 is spaced on the surface corresponding to the depth dimension of the functional units 2 to 5 in the upper row, and the functional units 2 to 5 of the functional units 2 to 5 are spaced from each other. A pair of upper support frames 43, 44 with a space corresponding to the vertical dimension.
Is arranged. Similarly, each functional unit 6 in the lower row
Two pairs of lower support frames 45, 46 are arranged at intervals corresponding to the depth dimension of 10 to 10 and at intervals corresponding to the vertical dimension of each of the functional units 6 to 10. Between the upper support frames 43 and 44, the main circuit power supply unit 2, the additional capacitor units 3 and 4, and the small signal power supply unit 5 are detachably attached in consideration of maintenance, and between the lower support frames 45 and 46. A two-axis inverter unit 6, 7, 8, a lower control unit 9 and a higher control unit 10 are detachably attached to the.

A regenerative resistor 47 is provided on the front side of the main circuit power supply unit 2. The regenerative resistor 47 is for consuming and absorbing regenerative electric power generated in the servo motor when a deceleration command is issued to the servo motor. Main circuit power supply unit 2 with regenerative resistor 47 opposite to backplane 1
The regenerative resistor 47 is disposed on the front surface side (in front of the unit insertion mounting direction) in order to eliminate the thermal influence on the internal circuit due to its heat generation during operation.

On the front side of the biaxial control units 6, 7, and 8 (front side in the unit insertion mounting direction), each unit 6,
The cooling fins 4 project outside the casings 7 and 8
8, 49, 50 are provided. This cooling fin 4
8, 49, 50 are 5 in the two-axis control unit 6, 7, 8.
The heat generated from the power transistors used in Nos. 2 and 56 is radiated. The extending direction of the convex strips (blades) of each cooling fin 48, 49, 50 is preferably the vertical direction from the viewpoint of heat dissipation efficiency.

In this way, the two-axis control units 6, 7, 8
On the front side (front side of the unit insertion direction) of the cooling fin 4
8, 49, and 50 can be arranged as in the present invention by eliminating the cable on the entire surface and arranging each functional element unit 2 to 2.
This is because 5 and 6 to 8 are collectively laid out in two stages for each function. The cooling fins 48 to 50 are
Since the units 6 to 8 are provided so as to project to the outside of the casing, heat does not stay inside the casing, suppresses thermal influence on the internal circuit, and causes instability of circuit operation such as temperature drift. Can be eliminated, and as a result, the reliability of the control operation can be improved.

FIG. 3 shows how the connectors are attached to the backplane. As shown in FIG. 3, backplane 1
A connector that corresponds to the mounting position of each of the units 2 to 10 on the front side of the unit and that can be engaged with a unit side connector (not shown) provided on the back side of each of the units 2 to 10, for example, in a male-female relationship. 30 to 42 are provided.

When arranging and fixing the units 2 to 10 to the back plane 1, the units 2 to 10 are inserted from the entire surface side toward 1 and the upper support frames 43, 44,
By screwing the lower support frames 45 and 46 to each other, the unit side connector and the board side connectors 30 to 42 are engaged with each other, and the backplane 1 is preliminarily formed with a printed wiring layer. Most of the circuitry of the controller will be wired.

(II) Circuit Configuration and Connection Relationship of Each Functional Element Unit FIG. 4 shows a circuit configuration and connection relationship of each functional element unit. The functional element units 2 to 10 shown in FIG.
The arrangement on the backplane 1 does not correspond to FIG. 1, but shows an electrical connection relationship.

As shown in FIG. 4, each functional element unit 2
10 to 10 are electrically connected via the board-side connectors 30 to 42. The connection wiring is formed by a printed wiring layer printed in advance on the back plane 1.

Next, details of each functional element unit will be described.
This multi-axis motor control device is roughly divided into a large power system circuit and a small signal system circuit. First, focusing on the circuit of the large power system, the three-phase AC power (for example, AC200V) supplied from the commercial power supply 11 is supplied to the power supply connector 1
It is input to the main circuit power supply unit 2 via 2.

The main circuit power supply unit 2 includes a converter 2A for converting three-phase AC power into DC power, and a capacitor C for smoothing the ripple component of the rectified output. The converter 2A includes, for example, a three-phase bridge rectifier circuit including a diode, a regenerative resistor for absorbing regenerative power, and an on / off circuit (not shown) of the regenerative resistor. The obtained direct-current power (for example, DC280V) is supplied to the biaxial inverter units 6, 7, and 8 via the additional capacitor units 3 and 4 and the inverter large-current connectors 38, 39, and 40, respectively.

The additional capacitor units 3 and 4 are capable of promptly compensating for the capacity when the capacity of the smoothing capacitor becomes insufficient due to a change in the specification of the driving capacity required for the multi-axis motor control device. It is the one.

The DC power supplied to the biaxial inverter units 6, 7 and 8 is given to the inverter 52 provided in each unit and used as the drive power for the servomotors M1 to M6. The configuration of the inverter 52 will be described later.

The small signal power supply unit 5 is a converter 2A.
It includes a base drive circuit of a power transistor which constitutes each inverter 52, and a 5V power source for a small signal system unit described later, and is specifically configured by using a constant voltage power source such as a switching regulator.

Next, paying attention to the small signal system circuit, the external control signal from the external setting unit 29 (see FIG. 1) is input to the upper control unit 10 via the serial communication connector 27. The upper control unit 10 is for transmitting the input external control signal to the lower control unit 9, and is a control unit belonging to the upper control unit of the lower control unit 9. (III) Lower control unit (6-axis control unit)

The lower control unit 9 receives external control signals from the upper control unit 10, control parameter setting signals input from the communication line 28 (see FIG. 1) through the serial communication connector 24, and the encoder connector 23. Based on encoder signals e1 to e6 from the encoders E1 to E6 fed back by feedback, PWM signals a1 to a6, current serial signals b1 to b6 or other internal correction signals, and a control program stored in the built-in microcomputer 57. Central feedback control of the axis inverter units 6, 7, 8 is performed, that is, servo control is performed.
Therefore, all the servomotors M1 to M6 for six axes are centrally controlled by the lower control unit 9.

FIG. 5 shows a detailed configuration example including the functional blocks of the lower control unit 9. The lower control unit 9
The servo motors M1 to M6 are composed of six control loops corresponding to the six axes. In order to simplify the description, one axis will be described below.

One control loop has a position control unit 60, a speed control unit 61, a current control unit 62, and a PWM signal generation unit 63, and the SP (serial / parallel) conversion unit 64 is shared by two control loops. . Upper control unit 10 to 6
1-axis position target value Pref for 1-axis, 1-axis speed target value Sref,
The 1-axis current target value Iref is the control upper I / F connector 41,
Position control unit 6 via upper board interface 73
0, speed controller 61, and current controller 62, respectively. On the other hand, the encoder signals e1 to e6 are also transmitted via the encoder connector 23 to the position control unit 60 and the speed control unit 6
1 is input to the current control unit 62. Further, the uniaxial current detection value Idet is input to the current control unit 62 via the SP conversion unit 64.

The position control unit 60 uses the 1-axis position target value Pref
And the 1-axis position detection value P converted from the encoder signal e1
The difference value is compared with ref and is output as a speed command s, which is sent to the speed control unit 61. The speed control unit 61 compares the speed command and the one-axis speed detection value Sdet converted from the encoder signal e1 with the difference value and the speed target value S
A current command i is generated based on ref and sent to the current controller 62. The current control unit 62 converts the current amplitude command value obtained by adding the uniaxial current target value Iref and the current command i into a two-phase current command value according to the motor magnetic pole position obtained from the encoder signal e1 to detect the current. A voltage command v for one axis and three phases is generated based on the value Idet, the gain correction data cg from the correction unit 71, and the offset correction data co and sent to the PWM signal generation unit 63. The PWM signal generator 63 receives the input 1
PWM (pulse width modulation) based on the voltage command v for the three axes
The signal a1 is generated and the control inverter I / F connector 37 is generated.
Supply to the servomotor M1 through. Abnormality processing unit 7
0, the correction unit 71 is a detection error correction unit of the current detector 54 described later, and the gain correction is performed based on the parallel data obtained by converting the microcomputer serial signals c1 to c3 from the microcomputer 57 by the SP conversion units 67, 68 and 69. Data c
g and offset correction data co are generated.

FIG. 6 shows a hardware configuration example of the lower control unit 9. As shown in FIG. 6, the lower-level control unit 9 controls C which controls the lower-level control unit 9 as a whole.
The PU 77 has a RAM 76, an EEPROM (or flash memory) 107, a DP-RAM (dual port RAM) 79, a serial communication interface 72, and a PW.
An M signal generation unit 63, SP conversion units 64-66, a magnetic pole position data conversion unit 74, and a position detection counter 75 are connected via a bus 78.

The DP-RAM 79 is the upper control unit 10
It functions as a data buffer for sending and receiving data to and from. The reason why the dual port is adopted is that the high speed of data communication is emphasized.

FIG. 7 shows an example of processing contents of the CPU 77 of the microcomputer 57 in the lower control unit 9. As shown in FIG. 7, the position control unit 60, the speed control unit 61, and the current control unit 62 executed in FIG. 5 are all time-divisionally processed by the software processing of the high-speed CPU 77.

(IV) Biaxial Inverter Unit Referring again to FIG. 4, biaxial inverter units 6, 7,
8 will be described. In order to simplify the description, only the biaxial inverter unit 6 will be described, and a 2-axis inverter unit 6 having the same configuration will be described.
The description of the shaft inverter units 7 and 8 is omitted.

The biaxial inverter unit 6 includes biaxial inverters for the servomotors M1 and M2.
The number of axes is not limited to two, and generally n (plural) axes may be used. The reason for including a plurality of inverters in one inverter unit is to simplify the circuit configuration and reduce the cost.

In FIG. 4, the PWM signal a1 from the lower control unit 9 is input to the dead time creating section 51. The dead time creation unit 51 is
The turn-on timing of the pair of power transistors is shifted in order to prevent the generation of a through current due to the simultaneous turning on of the pair of power transistors connected in series to the phase arm. The output from the dead time generator 51 is input to the inverter 52.

The inverter 52 is an inverse converter for converting DC power into three-phase AC power of PWM wave, and is generally constructed by connecting a power transistor to a bridge. The three-phase AC power output from the inverter 52 is supplied to the servomotor M1 via the power line connector 13 and the motor wiring 16 (FIG. 1) 38. Similarly, the PWM signal a2 from the lower control unit 9 is input to 55. The output from the dead time generator 55 is input to the inverter 56. The three-phase AC power output from the inverter 56 is supplied to the servomotor M2 through the inverter large current connector 38 and the power line connector 13 and the motor wiring 17 (FIG. 1).

Now, the drive current detection feedback loop in the biaxial inverter unit 6 will be described. First, the outline will be described. Two phases of three-phase output of the inverter 52
And the two phases of the three-phase output of the inverter 56 are respectively wired to the current detector 54, and the output drive currents of the inverters 52 and 56 are monitored. The current detector 54 is shared by the inverters 52 and 56, and the current detection gain is switched by the switching signal from the microcomputer 57. The current detection value of the current detector 54 is converted into a digital signal by the A / D converter 53, and the SP converter 6 of the lower control unit 9 is converted.
Sent to 4. This current detector 54 and A / D converter 53
Loop constitutes a feedback loop of the drive current of the inverters 52 and 56.

(V) Current Detector FIG. 8 shows a detailed circuit example of the A / D converter 53 and the current detector 54 in the biaxial inverter unit 6 and the connection relationship with the lower control unit 9. As shown in FIG.
A current detection resistor RA1 is connected to the output wiring of the inverter 52,
RB1 is inserted, the voltage across the current detecting resistor RA1 is equivalent to one phase of the inverter 52 as a drive current detection signal to the isolation amplifier 82, and the voltage across the current detecting resistor RB1 is equivalent to two phases of the inverter 52. 83 as a drive current detection signal
Respectively. Similarly, current detection resistors RA2 and RB2 are inserted in the output wiring of the inverter 56, and the voltage across the current detection resistor RA2 is 1 of the inverter 56.
The drive current detection signal for the phase is input to 84, and the voltage across the resistor RB2 for current detection is input to the drive current detection signal for the two phases of the inverter 56 to 85.

The isolation amplifiers 82 to 85 are amplifiers for electrically insulating the output wiring of the inverters 52, 56 of the high power system and the small signal system of the feedback loop, and perform electrical / optical / electrical conversion or electrical / magnetic conversion. / Configured by electrical conversion. The output signals of the isolation amplifiers 82 to 85 are input to the variable gain amplifiers 86 to 89.

The variable gain amplifiers 86 to 89 are composed of operational amplifiers and have different ratings for the servomotors M1 to M6 to be controlled by the multi-axis motor control device (for example,
5A motor, 10A motor, etc.)
This is to allow the same multi-axis motor control device to cope with a change in specifications. That is, in the conventional case (FIG. 14), the target servo motor M
When 1 to M6 are replaced with motors of different ratings, the motor control devices U1 to U6 to be driven are also replaced according to the ratings of the new servo motors M1 to M6, and the cable 201,
Rewiring of 209 and 210 was required. However, as in this embodiment, the additional capacitor units 3 and 4 (FIG. 1,
Variable gain amplifiers 86 to 8 (see FIG. 4) are removable.
The use of 9 eliminates the need to newly design and manufacture the multi-axis motor control device.

FIG. 9 shows a circuit example of the variable gain amplifier 86 (the same applies to 87 to 89). As shown in FIG. 9, the variable gain amplifier 86 switches the feedback resistors (2R, R, R) of the operational amplifier 101 to the changeover switch SW1.
, SW2 to change the gain of the operational amplifier 101, that is, the amplification degree. The changeover switches SW1 and SW2 can be realized by analog switches and are changed over by a gain changeover signal f from the microcomputer 57. In this circuit, the gain can be switched in two stages, but in general, it can be switched in n (plural) stages, and such diversion belongs to the technical scope of the present invention. The changeover operation is such that the changeover switch SW1 is ON when the gain changeover signal f is logic "1", and the changeover switch SW2 is ON when the gain changeover signal f is logic "0".

(VI) A / D Converter Referring again to FIG. 8, the A / D converter 53 is composed of a 4-channel input / serial output type A / D converter, and includes a current detector 54 and Similarly, it is shared by the inverters 52 and 56. As shown in FIG. 8, the A / D converter 53 includes an input switching unit 90 and an A / D conversion unit 91. Input switching unit 9
Reference numeral 0 is a selector for selectively transmitting the four-channel current detection value signals from the variable gain amplifiers 86 to 89 to the A / D conversion unit 91, which is synchronized by the DI output from the A / D conversion control unit 94. One of the four channel current detection value signals is passed through the A / D converter 91 in synchronization with the signal SCLK. The A / D conversion unit 91 receives the clock signal SCL by the straw unit signal -CONV from the A / D conversion control unit 94.
The current detection value signal is converted into a digital signal in synchronization with K, and the converted serial current detection value signal DO12 is sent to the SP conversion unit 64 of the lower control unit 9. The serial current detection value signal DO12 sends out the current detection values of the first and second axes in a time division manner, and does not include the current detection values of the two axes at the same timing.

As described above, when A / D-converting the current detection values of the two axes, the 4-channel parallel input / serial output A / D converter 53 is used, and the two axes are commonly used. As shown in FIG. 12, the number of signal lines can be reduced to 6 for 6 axes, and the number of signal pins is also reduced to 6, which leads to reduction of the number of signal lines and miniaturization of the connector. It is also possible to downsize the biaxial inverter unit 6 itself. FIG. 13 shows an old and new control example of the number of signal pins due to the difference in the configuration of the A / D converter. In this regard, conventionally, for example, a 2-channel input 12-bit parallel output type A / D converter is used for each inverter, and in this case, the signal line connected to the lower control unit 9 is A total of 19 = 12 for 6 axes
This (A / D converter output) + 1 (Channel switching signal line)
+6 (selection signal lines of 6 A / D converters) are required, and accordingly, 19 signal pins of the connector corresponding to the number of signal lines are also required.

(VII) Offset correction and gain correction in the current detector By the way, when the gain switching of the variable gain amplifiers 86 to 89 is performed in this way, the gain calibration is performed according to the rated current of the specified motor. It is important to do so in order to maintain control accuracy. Further, an error characteristic of a general operational amplifier is an offset, and there are variations among individual operational amplifiers. Incidentally, in the past, offset correction was manually adjusted by a variable resistor attached to the operational amplifier, but the work efficiency was poor.

From the above, the lower control unit 9
Is provided with correction means for automatically and digitally performing gain correction and offset correction accompanying gain switching in the current detectors 54 of the two-axis inverter units 6, 7, 8.

FIG. 10 shows the principle of a correction circuit for offset correction and gain correction of the variable gain amplifiers 86 to 89. As shown in FIG. 10, the offset correction and the gain correction are performed by converting the serial data of DO12, DO34, and DO56 for six axes sent from the two-axis inverter units 6, 7, and 8 into parallel data (for 12 channels). ), And the offset correction data co generated by the correction unit 71 from the DO12, DO34, and DO56 is subtracted from the subtracter 9
The offset component m is removed by subtraction in 2, and the correct value from which the offset component is removed is multiplied by the gain correction data cg corresponding to the gain required for the multi-axis motor control device. In this case, the current detection value data for which the offset correction and the gain correction for 12 channels thus obtained are multiplied and the current detection value data is fed back to the current control unit 62.

FIG. 11 shows a detailed example of a correction circuit for automatically performing the offset correction and the gain correction. First, offset adjustment is performed. For that purpose, the isolation amplifier 82, the variable gain amplifiers 86 to 89, the input switching unit 90,
Also, it is necessary to know how much the total offset amount of the A / D converter 91 is. As an example, a description will be given of a method of adjusting the offset and the gain of the isolation amplifier 82, the variable gain amplifier 86, the input switching unit 90, and the A / D conversion unit 91. The same applies to other channels.

To detect this offset amount, a dummy current is not passed through the output line of the inverter 52 (zero [A]), and the output data (current detection value) of the A / D converter 53 at this time is set to 64. Captured via SP-OUT
Is input to the subtractor 97. Further, the data of the target value REF0 (zero [A]) is sent from the memory 95 to the subtractor 97 via the target value switching unit 96. At this time, no voltage drop occurs in the current detection resistors RA1 and RB1, and the current detection value originally output from the A / D converter 53 should be zero [A].

Therefore, the difference value calculated by the subtractor 97 at this time is the isolation amplifier 82, the variable gain amplifier 86,
It can be seen that this corresponds to the total offset component of the input switching unit 90 and the A / D conversion unit 91. Therefore, this difference value is used as the offset correction data c of the variable gain amplifier 86.
O is stored in the correction data memory 99 via the correction operation switching unit 98, and at the same time converted to serial data by 67, and then EEPROM via the microcomputer 57.
Write to 59.

Then, the gain correction data cg in the 5 [A] operation mode is calculated and written in the EEPROM 59. First, the constant current source 104, the probe selector 105, and the probe 106 are connected to the output lines of the inverters 52 and 56.
Thus, a dummy current of 5 [A] is passed, the terminal voltage (that is, the current detection value) of the current detection resistor RA1 at this time is detected, and the data is given to the subtractor 97. On the other hand, the target value REF5 (5 [A]) is given from the memory 95 to the subtractor 97, and the offset correction data co is read from the correction data memory 99 and given to the subtractor 97. By performing the subtraction in the subtractor 97 in this state, the gain correction data cg in the 5 [A] operation mode which does not include the offset component is obtained. This gain correction data cg is stored in the correction data memory 99 and is sent to the microcomputer 57 via the SP converter 67.
It is written in the EEPROM 59.

Then, the gain correction data cg in the 10 [A] operation mode is calculated and written in the EEPROM 59. As in the case of the 5 [A] operation mode, first, the constant voltage source 104, the probe switch 105 and the probe 106 are connected to the output lines of the inverters 52 and 56 so that 10
A dummy current of [A] is passed, the terminal voltage (that is, the current detection value) of the current detection resistor RA1 at this time is detected, and the data is given to the subtractor 97. On the other hand, memory 9
The target value REF10 (10 [A]) is given to the subtractor 97 from 5, and the offset correction data co is read from the correction data memory 99 and given to the subtractor 97. By performing the subtraction in the subtractor 97 in this state, the gain correction data cg in the 10 [A] operation mode in which the offset component is not included is obtained. This gain correction data cg is stored in the correction data memory 99 and at the same time SP
It is sent to the microcomputer 57 via the converter 67, and EEPRO
Written to M59.

Similarly, by performing the above operation on the other three channels (systems of RB2, RA1 and RB2), the offset correction data co and the gain correction data cg of each are obtained and automatically written in the EEPROM 59. Get caught.

The above series of operations is executed by the timing control of the EEPROM write control unit 100.
The EEPROM writing control unit 100 operates according to a start signal from the outside.

The offset correction data co and the gain correction data cg thus written are supplied from the EEPROM 59 via the microcomputer 57 to the current control unit 62 of the lower control unit 9 during the control operation of the multi-axis motor control device. Be used for.

As described above, since the offset correction data co and the gain correction data cg can be automatically generated, the adjustment efficiency can be improved, and the accuracy can be improved because it is digitally performed.

(VIII) External Setting System for Control Program etc. The motor control device of the present invention is configured so that the control program and control parameters can be changed from the outside.

That is, the external setting unit 29 is connected to the upper control unit 10 as shown in FIG. 1, and the upper control unit 10 controls the control upper I / F connector 41 as shown in FIGS. 4 and 5. 6 to the upper board interface 73 in the lower control unit 9, and further to the CPU 77 and the EEPROM 107 in the lower control unit 9 via the DP-RAM 79 as shown in FIG.

As shown in FIG. 1, an external setting device 26 is connected to the lower control unit 9 via a serial communication connector 24, and this connector 24 is connected to a serial communication interface 72 in the lower control unit 9. Has been done. As shown in FIG. 6, the serial communication interface 72 includes CPUs 77 and E in the lower control unit 9.
It is connected to the EPROM 107. This EEPROM
In addition to the control program of the motor control device, control parameters (for example, gain data of the variable gain amplifiers 86 to 89 of the current detector 54, control gain, limit value of drive current, etc.) are stored in 107. .

In the above configuration, when any or all of the servomotors M1 to M6 to be controlled are replaced with motors having different ratings, the new servomotors M1 to M6 are adjusted to the rated values and constants. The control program or control parameters must be changed. In this case, when new control program data is input from the external setter 29 (see FIG. 1), the data is transferred via the upper control unit 10 to the DP-RAM 79 of the lower control unit 9.
Is input to The DP-RAM 79 sends new control program data to the CPU 77. The CPU 77 writes new control program data in the EEPROM 107 and updates the data. Therefore, the CPU 77 thereafter controls the motor based on the new control program.

On the other hand, when the control parameter is changed, when new control parameter data is input from the external setting device 26 (see FIG. 1), the data is directly input to the serial communication interface 72 of the lower control unit 9. The serial communication interface 72 sends the new control parameter data as parallel data to the CPU 77. CPU 77 EEPs new control parameter data
The data is updated by writing to the ROM 107. Alternatively,
The external setting unit 29 may indirectly input to the CPU 77 via the route of the upper control unit 10 and the lower control unit 9. By doing so, the degree of freedom of setting input is secured. From then on, the CPU 77 will perform motor control based on new control parameters.

The updating operation of the control program and the updating operation of the control parameter can be selectively executed independently of each other.

As described above, since the control program and the control parameter can be updated after the fact, there is no need to replace the hardware when the motor is changed, the maintenance cost can be reduced, and the motor control can be performed. It is possible to speed up the startup of the device.

Here, in FIG. 14, the servomotors M1c to
An outline of the M6 current control unit 62 (see FIG. 5) is shown. FIG.
4, the current amplitude command value τc for the servo motor
(n), the added value of the guaranteed current value τr (n) is limited by the torque limit value τlim1 in the torque command limiter 110. The output τ′c1 (n) of the torque command limiter 110 is coordinate-converted by the angle parameter θ (n) in the current command generator 111, and the current command generator 111 outputs the current command ic.
generates (n). The current command ic (n) is expressed by the following equation.

[0069]

[Equation 1] The current command ic (n) is detected by the subtraction unit 112 as the detected current if (n)
(See the 1-axis current detection value Idet in FIG. 5) and the subtraction unit 112 calculates a difference current value Δi (n) between the two. The differential current value Δi (n) is expressed by the following equation.

[0070]

[Equation 2] The current control 113 generates the uniaxial three-phase voltage command v (n) (see v in FIG. 5) based on the difference current value Δi (n).
The 1-axis 3-phase voltage command v (n) is expressed by the following equation.

[0071]

(Equation 3) Here, the 1-axis 3-phase voltage command vc (n) and the difference current value ΔI (n)
There is a relationship of

[0072]

[Equation 4]

[0073]

(Equation 5) K is a control gain. The control gain K and the torque limit value τlim correspond to control parameters.

[0074]

As described above, according to the present invention, various servo motors can be supported by setting and inputting desired gain data and current control parameter data through the communication interface when the servo motor is changed. The time and effort required to replace the ROM and the economic burden associated with the replacement are greatly reduced, and the versatility of the motor control device is ensured.

[Brief description of drawings]

FIG. 1 is an external perspective view showing an outline of an assembly structure of each unit in an embodiment of the present invention.

FIG. 2 is an external perspective view showing details of the assembly structure of each unit in the embodiment of the present invention.

FIG. 3 is an external perspective view showing how the connectors are attached to the backplane according to the embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration and a connection relationship of each unit in the embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration example of a lower control unit.

FIG. 6 is a block diagram showing a hardware configuration example of a lower control unit.

FIG. 7 is a block diagram showing an example of processing contents of a CPU of a lower control unit.

FIG. 8 is a block diagram showing a circuit around a current detector in the biaxial inverter unit.

FIG. 9 is a circuit diagram showing an example of a variable gain amplifier in a biaxial inverter unit.

FIG. 10 is a block diagram showing a principle configuration of a correction circuit for offset correction and gain correction of a current detector.

FIG. 11 is a block diagram showing a detailed example of an automatic correction circuit for offset correction and gain correction of a current detector.

FIG. 12 is a block diagram showing a wiring relationship between a biaxial inverter unit and a lower control unit.

FIG. 13 is an explanatory view showing a new and old comparative example of the biaxial inverter unit, the lower control unit, and the number of connector signal pins.

FIG. 14 is a block diagram showing an outline of a current control unit.

FIG. 15 is a block diagram showing a unit configuration example for one axis in a conventional multi-axis motor control device.

[Explanation of symbols] 1 backplane 2 main circuit power supply unit 3, 4 additional capacitor unit 5 small signal power supply unit 6, 7, 8 inverter unit (2 axes) 9 lower control unit (6 axes) 10 upper control unit 11 commercial power supply 12 power supply connector 13 to 15 power line connector 16 to 22 motor wiring 22 encoder signal line 23 encoder connector 24 serial communication connector 25 communication line 26 external setting device 27 serial communication connector 28 communication line 29 external setting device 30 Main circuit power supply connector 31 Additional capacitor connector 32 Additional capacitor connector 33 Small signal power supply connector 34 to 36 Inverter small signal connector 37 Control inverter I / F connector 38 to 40 Inverter large current connector 41 Control host I / F Ko Kuta 42 Upper connector 43, 44 Support frame 45, 46 Support frame 47 Regenerative resistor 48-50 Cooling fin 51 Dead time creation unit 52 Inverter 53 A / D converter 54 Current detector 55 Dead time creation unit 56 Inverter 57 Microcomputer 58 Abnormality detection unit 59 EEPROM 60 Position control unit 61 Speed control unit 62 Current control unit 63 PWM signal generation unit 64-69 SP conversion unit 70 Abnormality processing unit 71 Correction unit 72 Serial communication interface 73 Upper board interface 74 Magnetic pole position data conversion unit 75 Position detection counter 76 RAM 77 CPU 78 Bus 79 DP-RAM 82-85 Insulation amplifier 86-89 Variable gain amplifier 90 Input switching unit 91 A / D conversion unit 92 Subtractor 93 Multiplier 94 A / D conversion control unit 95 Memory 96 Target value switching unit 97 Subtractor 98 Correction operation switching unit 99 Correction data memory 100 EEPROM writing control unit 101 Operational amplifier 102 Inverter gate 104 Constant voltage source 105 Probe switching unit 106 Probe 107 EEPROM 110 Torque command limiter 111 Current command creation Section 112 subtraction section 113 current control section 114 SP conversion and current detection value correction section M1 to M6 servo motor E1 to E6 encoder RA1, RA2, RB1, RB2 current detection resistors a1 to a6 PWM signal b1 to b3 current serial signal c1 to c3 Microcomputer serial signal c0 Offset correction data cg Gain correction data e1 to e6 Encoder signal f, f1 f2 Gain switching signal CH-SEL Channel switching signal OG-SEL Correction data switching signal REF Target value REF0 0 Pair target value REF5 5 Ah target value Ref10 10 Ah target value SP-OUT SP conversion unit output signal OFFSET offset data

Claims (1)

[Claims] 1. A motor drive means for converting direct current power into alternating current power to supply a drive current to a servo motor, and a variable gain amplifier for amplifying a detection signal of the drive current according to the characteristics of the servo motor to be controlled, And a current detection unit that has an A / D converter that converts the amplified current detection signal into a digital signal and that feeds back the current detection signal to the motor driving unit. A central processing unit for controlling; a communication interface capable of receiving gain data of the variable gain amplifier and current control parameter data of the motor control device input from the outside and transmitting the data to the central processing unit; and the variable gain amplifier. A memory for electrically rewritably storing the gain data and the current control parameter data of The motor control device is characterized in that the central processing unit is configured such that gain data and current control parameter data sent from the communication interface can be written to and read from the memory.