KR20210099512A - Motor control method, motor drive device, industrial robot control method, and industrial robot - Google Patents

Abstract

When an abnormality occurs during position detection, the occurrence of an improper operation of an arm can be avoided due to an emergency stop of a motor (22). The present invention includes: a step (selectors (25, 32, 34) selecting 0) of driving a motor (22) through detection position feedback control, based on a position command value, and a position detection value transmitted from an encoder (30) mounted on the motor (22); a step (an encoder communication abnormality determination part (38)) of detecting whether the position detection value is abnormal; a step (a current detection part (31)) of detecting a current flowing the motor (22) being driven; and a step of switching a control mode of the motor (22) to sensor-less vector control (the selectors (25, 32, 34) selecting 1) for driving the motor (22) based on a result of estimating a rotation position of the motor (22) based on a three-phase current detection value, from the detection position feedback control, when an abnormality of the position detection value is detected.

Description

Motor control method, motor drive device, industrial robot control method, and industrial robot

The present invention relates to a motor control method, a motor driving device, a control method of an industrial robot, and an industrial robot.

Conventionally, a motor comprising a step of driving the motor by feedback control based on a rotational position command signal and a rotational position signal transmitted from a rotational position detector mounted on the motor, and a step of detecting the presence or absence of an abnormality in the rotational position signal. Control methods are known.

For example, in the motor control method described in patent document 1, a motor is driven as follows. That is, the motor is driven by feedback control based on the detection position information (rotational position signal) output from the encoder as a rotational position detector mounted on the motor, and the command position information (rotational position command signal) output from the controller. While the motor is being driven, it is determined whether the difference between the command position information (rotation position command signal) and the detected position information (rotation position signal) is equal to or greater than a predetermined value, and when it is equal to or greater than a predetermined value, it is assumed that an abnormality of the encoder has been detected. , Turn off the driving power to emergency stop the motor. According to patent document 1, according to such a motor control method, when an abnormality of an encoder occurs, a motor is emergency-stopped, and it becomes possible to stop the operation|movement of the robot which uses the motor as a drive source.

Publication WO2018-079075

However, in the motor control method described in Patent Document 1, if the motor is emergency stopped when an abnormality occurs in the detection position information due to a failure of an encoder or disconnection of a communication line, etc. . Specifically, while the entire arm is rotated in the vertical direction by the driving of the first motor, the elbow of the arm is bent and extended by the driving of the second motor to move the fingertips of the arm along a predetermined trajectory. Robots are known. In the robot having such a configuration, for example, based on abnormal occurrence of rotational position information (rotational position signal) output from an encoder that detects the rotational position of the second motor, the driving of the first motor and the second motor is emergency stopped. make it done Then, the fingertip of the arm is moved to a position deviated from the predetermined trajectory, and there is a fear that the arm may collide with nearby devices or structures. The reason that the fingertip of the arm moves to a position deviating from the predetermined trajectory is for the following reasons. That is, when the first motor and the second motor rotate with different driving amounts and the fingertip of the arm moves along a predetermined trajectory, if the two motors stop at the same time, the balance of the driving amount is broken and the fingertip of the arm moves along a predetermined trajectory. It deviates from a certain trajectory.

The present invention has been made in view of the above background, and an object thereof is to provide the following motor control method, a motor driving device, a control method for an industrial robot, and an industrial robot. That is, a motor control method capable of avoiding occurrence of inappropriate operation of an object to be operated (eg, an arm of an industrial robot) by emergency stop of the motor when abnormality of the rotational position signal occurs.

The first invention of the present application includes a step of driving the motor by feedback control based on a rotational position command signal and a rotational position signal transmitted from a rotational position detector mounted on the motor, and whether or not the rotational position signal is abnormal. A motor control method comprising a step of detecting, the step of detecting a current flowing through the motor during driving; and a step of switching from the feedback control to the sensorless vector control for driving the motor based on a result of estimating the rotational position of the motor based on the detection result of the current.

A second invention of the present application is a motor drive device for controlling the drive of a motor, and is characterized in that the drive of the motor is controlled by the motor control method of the first invention.

A third invention of the present application is a control method of an industrial robot that changes the position of an arm of the industrial robot by individually controlling the driving of a plurality of motors, wherein each drive of the plurality of motors is controlled by the motor control of the first invention It is characterized in that it is controlled by a method.

The fourth invention of the present application is an industrial robot that individually controls the driving of a plurality of motors to change the position of the arm, wherein each drive of the plurality of motors is controlled by the motor drive device of the second invention it is characterized by

According to these inventions, the excellent effect of being able to avoid generation|occurrence|production of the inappropriate operation|movement of the to-be-operated object by emergency stop of a motor at the time of abnormal occurrence of a rotation position signal is exhibited.

BRIEF DESCRIPTION OF THE DRAWINGS It is a perspective view which shows the industrial robot which concerns on embodiment.
Fig. 2 is a plan view showing the industrial robot.
3 is a block diagram showing a control configuration of a motor driving device mounted on the industrial robot, together with a motor and the like.
Fig. 4 is a flowchart showing a processing flow of a mode value selection process executed by a control mode selection unit of the motor driving apparatus.
Fig. 5 is a block diagram showing a control configuration of an open-loop control electric angle generating unit of the motor driving apparatus.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of the motor drive apparatus and industrial robot using the motor control method which concerns on embodiment of this invention is described, referring drawings. In addition, in the following drawings, in order to make each structure easy to understand, an actual structure and the scale, the number, etc. in each structure may differ.

First, the basic configuration of the industrial robot according to the embodiment will be described. 1 is a perspective view showing an industrial robot 1 according to an embodiment. 2 is a plan view showing the industrial robot 1 . The industrial robot 1 is a robot for conveying a glass substrate, and is provided with the arm 2, the mount 3, and the raising/lowering part 4. The lifting unit 4 is held by the mount 3 and is raised and lowered in the vertical direction (in the direction of the arrow in FIG. 1 ) by driving a lifting motor (not shown). The arm 2 is provided with the arm part 2A on which the glass substrate is mounted, the forearm part 2B, and the upper arm part 2C, and is hold|maintained by the raising/lowering part 4 .

The shoulder joint 2D, which is a connecting portion with the elevating portion 4 in the upper arm portion 2C, can be rotated in the horizontal direction by driving the first motor 22A. Specifically, when the rotational driving force of the first motor 22A is transmitted to the shoulder joint 2D through the first belt 2E, the shoulder joint 2D rotates in the horizontal direction. In addition, the elbow joint 2F, which is a connection portion between the upper arm portion 2C and the forearm portion 2B, can be rotated in the horizontal direction by driving the second motor 22B. Specifically, the rotational driving force of the second motor 22B is transmitted to the elbow joint 2F through the second belt 2G, whereby the elbow joint 2F rotates in the horizontal direction. In addition, the wrist joint, which is a connection portion between the forearm 2B and the hand 2A, can rotate in the horizontal direction by receiving the driving force of the second motor 22B through the belt.

In the industrial robot 1, in order to move the hand part 2A straight in the direction of the arrow along the trajectory indicated by the dashed-dotted line in FIG. It is necessary to rotate both joints. For that purpose, it is necessary to drive the first motor 22A and the second motor 22B with different driving amounts. When both motors are stopped without controlling the respective rotation positions of the first motor 22A and the second motor 22B, the balance of the driving amounts of both motors is disturbed, and the hand unit 2A is separated from the trajectory indicated by the dashed-dotted line. stop at an out-of-place position. Then, there exists a possibility that 2 A of receiving parts may collide with the surrounding structure and apparatus.

Next, a motor drive device using the motor control method according to the embodiment will be described.

3 is a block diagram showing a control configuration of a motor drive device 20 mounted on the industrial robot 1 according to the embodiment together with a motor 32 and the like. In addition, the industrial robot 1 is a motor drive device 20 shown in FIG. 3 , a motor drive device 20 for rotating the shoulder joint 2D of the arm 2 , and an elbow joint of the arm 2 ( 2F) and a motor drive device 20 for rotating the wrist joint and three motor drive devices 20 for lifting and lowering the lifting unit 4 are provided.

Each of the three motor drive devices 20 can switch and execute three of the detection position feedback control, the sensorless vector control, and the open loop control as a control method for driving the motor 22 .

The industrial robot 1 includes a host controller 100 that sends commands to three motor driving devices 20 . The host controller 100 transmits a position command value (position command signal) to each of the three motor drive devices 20 based on the control program stored in the storage medium. Each of the three motor drive devices 20 executes control to rotate the rotor of the motor 22 to a rotational position corresponding to the position command value sent from the host controller 100 . By this control, the arm 2 of the industrial robot 1 performs an operation based on the above-described control program.

The configuration of the three motor driving devices 20 is the same as each other. Accordingly, the configuration of only one of the three motor drive devices 20 will be described in detail below.

The motor drive device 20 includes a control mode selection unit 21 , a position speed control unit 23 , a vector control DQ axis current command generation unit 24 , a first selector 25 , a current control unit 26 , and a DQ inverse transformation A unit 27 , a PWM control unit 28 , and an inverter 29 are provided. The motor 22 driven by the motor drive device 20 is the first motor 22A, the second motor 22B, or the third motor described above. The motor drive device 20 includes a current detection unit 31 , a second selector 32 , a vector control electric angle generating unit 33 , a third selector 34 , a position estimation unit 35 , and an open loop control electric angle. A generator (36) is provided. Further, the motor drive device 20 includes an open loop control DQ axis current command generation unit 37 , an encoder communication abnormality determination unit 38 , and a DQ conversion unit 39 . The motor unit includes a motor 22 and a rotary encoder 30 .

The position command value output from the upper controller 100 is input to the position speed control unit 23 and the open loop control electric angle generation unit 36 of the motor driving device 20 .

In the arm 2 of the industrial robot 1, a turning operation (rotation of the shoulder joint 2D), a joint bending and extension operation (rotation of the shoulder joint 2D, the elbow joint 2F, and the wrist joint), or a lifting operation The motor 22 serving as a driving source is composed of a three-phase (U-phase, V-phase, W-phase) alternating current PM (Permanent Magnet) motor. The rotary encoder 30 as a rotational position detector mounted on the motor 22 detects the rotational position of the rotor of the motor 22 by a known technique, and uses the information of the detection result as a position detection value (rotational position signal). print out The output position detection value is input to the encoder communication abnormality determination unit 38 and the control mode selection unit 21 . The position detection value is also input to the position speed control unit 23 via the second selector 32 .

Hereinafter, rotation of the rotor of the motor 22 may be expressed as rotation of the motor 22 .

The encoder communication abnormality determination unit 38 detects the presence or absence of an abnormality with respect to the position detection value sent from the rotary encoder 30, and, when an abnormality is detected, sends an abnormality occurrence signal to the control mode selection unit 21 and the upper controller ( 100) is sent. As an example of a method for detecting an abnormality in the position detection value by the encoder communication abnormality determination unit 38, when the amount of time change in the position detection value exceeds a predetermined threshold (or is greater than or equal to the threshold), a method of detecting abnormality can be heard However, it is not limited to this method. Moreover, you may employ|adopt the method of detecting the abnormality of the rotary encoder 30 as abnormality of a position detection value as a method of detecting the abnormality of a position detection value.

The control mode selection unit 21 calculates the angular velocity of the motor 22 based on the amount of change per unit time of the position detection value sent from the rotary encoder 30, and the calculation result and the presence or absence of abnormality in the position detection value Based on , the control mode value is selected and output.

4 is a flowchart showing a processing flow of a mode value selection process executed by the control mode selection unit 21 . In the mode value selection process, first, it is determined whether or not an abnormality occurrence signal transmitted as needed from the encoder communication abnormality determination unit 38 has been received (S (step) 1). Then, when the abnormal occurrence signal is not received (N in S1), “0” is selected as the control mode value and output from the control mode selection unit 21 (S2). After that, the processing flow returns to S1.

On the other hand, when an abnormality occurrence signal is received (S1 to Y), it is then determined whether or not the angular velocity of the motor 22 is equal to or greater than a predetermined value (or exceeds a predetermined value) (S3). Then, when the angular velocity is equal to or greater than a predetermined value (Y in S3), "1" is selected as the control mode value and output from the control mode selection unit 21 (S4). On the other hand, if it is not equal to or greater than the predetermined value (or does not exceed the predetermined value) (N in S3), "2" is selected as the control mode value and output from the control mode selection unit 21 .

As described above, in the control mode value selection process, when no abnormality in the position detection value has occurred, “0” is selected as the control mode value. In addition, when an abnormality in the position detection value occurs and the angular velocity is greater than or equal to a predetermined value, “1” is selected as the control mode value. "2" is selected as

In addition, the predetermined value mentioned above is 10 [%] of the rated angular speed of the motor 22, for example.

When an abnormality occurrence signal is sent from the motor drive device 20, the host controller 100 transmits the position command values transmitted to the three motor drive devices 20 to the arm (2) while moving the arm 2 on a predetermined trajectory. 2) and the motor 22 are changed to a pattern for decelerating and stopping. Thereby, the arm 2 stops on a predetermined|prescribed trajectory.

In Fig. 3, the control mode values output from the control mode selection unit 21 are the first selector 25, the second selector 32, and the third selector 34 (hereinafter these are collectively referred to as three selectors). (also called 25, 32, 34)). Each of the three selectors 25 , 32 , and 34 has an input terminal 0, input terminal 1 and input 2, and outputs an output based on the control mode value sent from the control mode selection unit 21 . switch the signal. Specifically, each of the three selectors 25, 32, and 34 outputs a signal input to the 0 input terminal when the control mode value is “0”, and outputs the signal input to the 0 input terminal when the control mode value is “1”. Outputs a signal input to , and in the case of “2”, outputs a signal input to the second input terminal.

The following signals are output from each of the three selectors 25, 32, and 34 of this configuration. That is, when abnormality in the position detection value does not occur (control mode value = 0), the detection position feedback that rotates the motor 22 from the position indicated by the position detection value to the position indicated by the position command value. A signal for executing control is output. In addition, when an abnormality in the position detection value occurs and the angular velocity of the motor 22 is equal to or greater than a predetermined value (or exceeds a predetermined value) (control mode value = 1), the motor is controlled by sensorless vector control to be described later. A signal for driving (22) is output. Further, when an abnormality in the position detection value occurs and the angular velocity of the motor 22 is less than a predetermined value (or less than or equal to a predetermined value) (control mode value = 2), the motor 22 is controlled by open-loop control to be described later. A signal for driving is output.

Among the three control methods described above, first, the detection position feedback control will be described.

When there is no abnormality in the position detection value output from the rotary encoder 30, the motor drive device 20 drives the motor 22 by detection position feedback control. Specifically, when there is no abnormality in the position detection value, the position detection value is output from the second selector 32 and is input to the position speed control unit 23 and the vector control electric angle generation unit 33 as a position feedback value. do. The position speed control unit 23 calculates a torque value required to rotate the motor 22 from the position indicated by the position feedback value to the position indicated by the position command value, and sends it to the vector control DQ axis current command generation unit 24 . print out Further, the vector-controlled electric angle generating unit 33 generates an electric angle based on the position feedback value. This electric angle is input to the DQ conversion unit 39 through the third selector 34 .

The vector control DQ-axis current command generation unit 24 is configured to generate a D-axis current and a Q-axis current required to generate a torque equal to the input torque value in the motor 22, the D-axis current command value and the Q-axis A current command value (hereinafter these are also referred to as DQ axis current command values) is generated. The D-axis current is a component parallel to the magnetic flux of the permanent magnet among the currents flowing through the motor 22 . In addition, the Q-axis current is a component orthogonal to the magnetic flux of the permanent magnet among the currents flowing through the motor 22 .

The DQ-axis current command value output from the vector control DQ-axis current command generation unit 24 is input to the input terminal 0 and the input terminal 1 of the first selector 25 . The DQ axis generated by the vector control DQ axis current command generation unit 24 when detection position feedback control is executed (control mode value = 0) and when sensorless vector control is executed (control mode value = 1) A current command value is output from the first selector 25 . This DQ-axis current command value is input to the current control unit 26 .

The DQ conversion unit 39 generates a D-axis current feedback value and a Q-axis current feedback value (hereinafter also referred to as a DQ-axis current feedback value) based on the electric angle sent from the third selector 34 to generate a current control unit ( 26) is printed. In addition, at the time of sensorless vector control which will be described later, the DQ conversion unit 39 sets the DQ axis based on the electric angle transmitted from the third selector 34 and the three-phase current detection value transmitted from the current detection unit 31 . Generates a current feedback value.

The current controller 26 generates a DQ-axis voltage command value based on the DQ-axis current command value sent from the first selector 25 and the DQ-axis current feedback value sent from the DQ converter 39 to generate a DQ output to the inverse transform unit 27 .

The DQ inverse conversion unit 27 converts the required D-axis current and Q-axis current to the motor 22 based on the electric angle sent from the third selector 34 and the DQ-axis voltage command value sent from the current control unit 26 . ), a U-phase voltage command value, a V-phase voltage command value, and a W-phase voltage command value (hereinafter also referred to as a three-phase voltage command value) are generated and output. The three-phase voltage command value output from the DQ inverse transform unit 27 is input to the PWM control unit 28 . The PWM control unit 28 is a PWM signal for outputting the U-phase voltage, V-phase voltage, and W-phase voltage represented by the U-phase voltage command value, V-phase voltage command value, and W-phase voltage command value from the inverter 29 . A U-phase gate signal, a V-phase gate signal, and a W-phase gate signal are output. The inverter 29 supplies the U-phase voltage, V-phase voltage, and W-phase voltage based on the U-phase gate signal, V-phase gate signal, and W-phase gate signal to the motor 22 to rotate the motor 22 . .

The current detection unit 31 detects a U-phase current, a V-phase current, and a W-phase current (hereinafter, also referred to as three-phase current) flowing from the inverter 29 to the motor 22 , and outputs the detection result to the U-phase current. It outputs as a detection value, a V-phase current detection value, and a W-phase current detection value (hereinafter also referred to as a three-phase current detection value). In addition, instead of detecting the current values of the three phases, only the current values of two phases among the three phases may be detected, and the current values of the remaining one phase may be calculated based on the detection results of the current values of the two phases.

When there is no abnormality in the position detection value output from the rotary encoder 30, the motor 22 is driven by the detection position feedback control as described above.

Next, sensorless vector control will be described. When sensorless vector control is executed, that is, when there is an abnormality in the position detection value and the angular speed of the motor 22 immediately before the occurrence of the abnormality is equal to or greater than a predetermined value (or exceeds a predetermined value) (control mode value = 1) In this case, the motor 22 is driven as follows. That is, the three-phase current detection value output from the current detection unit 31 is input to the DQ conversion unit 39 . The DQ converter 39 generates and outputs a DQ-axis current feedback value based on the three-phase current detection value and the electric angle sent from the third selector 34 . The output DQ-axis current feedback value is input to the current control unit 26 and the position estimation unit 35 .

The current control unit 26 generates and outputs a DQ-axis voltage command value based on the DQ-axis current command value sent from the first selector 25 and the DQ-axis current feedback value sent from the DQ converter. The position estimation unit 35 estimates the rotational position of the motor 22 based on the DQ axis voltage command value sent from the current control unit 26 and the DQ axis current feedback value sent from the DQ conversion unit 39 . do.

The position estimation unit 35 obtains a position estimation value and an electric angle estimation value based on the DQ-axis current feedback value sent from the DQ converter 39 and the DQ-axis voltage command value sent from the current control part 26 . . Then, the position estimation unit 35 outputs the estimated position value to the first input terminal of the second selector 32, and further outputs the electric angle estimated value to the first input terminal of the third selector.

The position estimation value output from the position estimation unit 35 is input to the position velocity control unit 23 as a position feedback value via the second selector 32 . The position/speed control unit 23 outputs a torque command value in the same manner as the detection position feedback control except that the position estimation value is used as the position feedback value. The processing until input to the inverter 29 as a U-phase gate signal, a V-phase gate signal, and a W-phase gate signal based on this torque command value is the same as the detection position feedback control. That is, in the sensorless vector control, a position estimation value based on an induced voltage generated in the motor 22 is fed back to the position speed control unit 23 as a position feedback value instead of the position detection value, except for the detection position feedback control. The same processing as

Further, in the sensorless vector control, the motor drive device 20 lowers the control loop gain of the position speed control compared to the detection position feedback control. As an example of a method of lowering the control loop gain, a method of lowering the control loop gain according to a command from the host controller 100 is exemplified. In order to maintain the trajectory of the arm 2 with high precision, it is desirable to reduce not only the motor drive device 20 in which the position detection value abnormality occurred, but also the control loop gain of the position and speed control of the other motor drive devices 20 . . According to the command of the host controller 100 , it is possible to appropriately lower the control loop gain of the position speed control in all the motor driving devices 20 .

As another example of lowering the control loop gain of the position and speed control of the motor driving device 20 , the position and speed control of the motor driving device 20 is performed by the processing of the motor driving device 20 causing an abnormality in the position detection value. A method of lowering only the control loop gain of As an example of the processing of this method, in the configuration for controlling the position and the velocity by P-PI control, a method of lowering each of the velocity loop gain, the position loop gain, and the velocity loop integral gain is exemplified. Further, as another example, for example, in Japanese in the structure for controlling the position and speed by the RPP control as described in the publication No. 2002-229604 [Patent Publication, gain ω _2, ω ₁ gain, lowering the gain ω _q ways to do it can be found. Further, as another example, in a configuration in which the position and speed are controlled by RPP control, a method of lowering the inertia-nominal set value is exemplified. By lowering the inertia nominal setting value, it is possible to approximately _{lower the ω 2} gain and the ω _{1 gain.} According to this method, the control loop gain can be appropriately lowered without constructing a dedicated program for lowering the control loop gain.

Next, the open loop control will be described. When the open loop control is executed, that is, when there is an abnormality in the position detection value and the angular speed of the motor 22 is less than a predetermined value (or less than a predetermined value) (control mode value = 2), the motor (22) is driven. That is, the open-loop control electric angle generating unit 36 is a rotational position at which the magnetic pole of the motor 22 is drawn based on the position command value sent from the host controller 100 (hereinafter referred to as a forced synchronous position command value). is calculated and output to the open loop control DQ axis current command generation unit 37 . Further, the electric angle is calculated based on the position command value and output to the third selector 34 .

5 is a block diagram showing the circuit configuration of the open-loop control electric angle generator 36 . The open-loop control electric angle generating unit 36 includes a controller 36a, a mechanical model 36b, and an electric angle calculating unit 36c. The controller 36a includes a position and speed control unit having the same configuration as that of the position and speed control unit 23 in FIG. 3 , and generates and outputs a torque command value based on the position command value sent from the host controller 100 .

The machine system model 36b includes a motor model and a load model for the motor. In addition, although illustration is abbreviate|omitted in FIG. 5 for convenience, the model 36b of a mechanical system is equipped with the model of an inverter, the model of a rotary encoder, and the model of a current detection part. These models are models built on the basis of an experiment using an actual industrial robot 1, and how the rotational position of the motor 22 changes when the torque command value is changed from the value before the change to the value after the change. A simulation algorithm is provided. The machine system model 36b generates and outputs the rotational position of the motor 22 as a position simulation value by substituting the torque command value sent from the controller 36a into the algorithm. The output position simulation value is input to the controller 36a. In addition, the position simulation value is input to the open loop control DQ axis current command generation unit 37 of FIG. 3 as a forced synchronous position command value. In addition, the position simulation value is input to the electric angle calculating part 36c. The electric angle calculation unit 36c calculates an electric angle estimate value based on the position simulation value, and outputs the calculation result to the DQ transform unit 39 and the inverse DQ transform unit 27 through the third selector 4 of FIG. 3 . output to

<Configuration 1>

(1) Configuration 1 of the motor control method used in the industrial robot 1 having the above configuration is a position command value (rotational position command signal) and a rotary encoder 30 (rotational position detector) mounted on the motor 22 . and a step of driving the motor 22 by detection position feedback control based on the position detection value (rotation position signal) transmitted from the . In this step, the position speed control unit 23, the vector control DQ axis current command generation unit 24, the vector control electric angle generation unit 33, the DQ conversion unit 39, the current control unit 26, and the DQ inverse transformation unit 27 are performed. ), PWM control unit 28, inverter 29, rotary encoder 30, and the like are realized by processing. In addition, in the configuration 1, a step of detecting the presence or absence of an abnormality in the rotation position signal (encoder communication abnormality determination unit 38) and a step of detecting a three-phase current flowing through the motor 22 being driven (current detection unit 31) to provide In addition, in configuration 1, when an abnormality in the position detection value is detected, the control method of the motor 22 is obtained by estimating the rotational position of the motor 22 based on the three-phase current detection value from the detection position feedback control. A step of switching to sensorless vector control for driving the motor 22 based on the result (Y→S4 in S3 in FIG. 4) is provided.

<Operation and Effects of Configuration 1>

In configuration 1, when an abnormality occurs in the position detection value, the rotational position of the motor 22 is estimated based on the three-phase current detection value flowing through the motor 22 by sensorless vector control, and the estimation result ( The rotational operation of the motor 22 is appropriately controlled based on the position estimation value). At this time, the motor 22 is decelerated according to the position command value (rotational position command signal) sent from the host controller 100 as a signal pattern to decelerate and stop the arm 2 of the industrial robot 1 along an appropriate trajectory. . Thereby, generation|occurrence|production of the improper operation|movement of the arm 2 by making the motor 22 emergency stop at the time of abnormal occurrence of a position detection value can be avoided. Therefore, according to the configuration 1, the arm 2 can be decelerated and stopped while moving along the target trajectory without colliding with the equipment or structures in the vicinity of the industrial robot 1 .

<Configuration 2>

Configuration 2 includes a step of driving the motor 22 by detection position feedback control based on the position command value and the position detection value transmitted from the rotary encoder 30 mounted on the motor 22 . In addition, in the configuration 2, the step of detecting the presence or absence of an abnormality in the position detection value and, when an abnormality in the position detection value is detected, the control method of the motor 22 is opened by the current drawing method from the detection position feedback control. A step of switching to loop control (N→S5 in S3 in FIG. 4) is provided.

<Effect of composition 2>

In the configuration 2, when an abnormality occurs in the position detection value, the rotational operation of the motor 22 is appropriately controlled by the open loop control by the current drawing method. At this time, the motor 22 is decelerated and stopped according to the position command value sent from the host controller 100 as a signal pattern for decelerating and stopping the arm 2 along an appropriate trajectory. Thereby, generation|occurrence|production of the improper operation|movement of the arm 2 by making the motor 22 emergency stop at the time of abnormal occurrence of a position detection value can be avoided. Therefore, according to the configuration 2, the arm 2 can be decelerated and stopped while moving along the target trajectory without colliding with the equipment or structures in the vicinity of the industrial robot 1 .

In addition, when an abnormality in the position detection value occurs, the change pattern of the position command value sent from the host controller 100 to stop the operation of the arm 2 (the object to be operated) causes the motor 22 to be driven. It is not limited to the pattern of simply decelerating and stopping. Depending on the structure of the arm 2, immediately after decelerating and stopping the motor 22, the motor 22 is rotated in reverse to perform reverse acceleration and deceleration in sequence, thereby stopping the arm 2 along an appropriate trajectory. There may be cases where it is possible.

<Configuration 3>

Configuration 3 includes the following components in addition to configuration 1. That is, when an abnormality in the position detection value is detected, the motor 22 is driven by sensorless vector control in a predetermined high-speed angular velocity region (a predetermined value or more) (Y→S4 in S3 in FIG. 4 ). In addition, in the low-speed angular-velocity region (less than a predetermined value) lower than the high-speed angular velocity region, the motor is driven by open-loop control by the current drawing method (N→S5 in S3 in Fig. 4).

<Operation and Effect of Configuration 3>

In the configuration 3, when the motor 22 is rotating at a relatively high speed, the induced voltage satisfactorily generated in the motor 22 is estimated by sensorless vector control, and the motor 22 is based on the estimated induced voltage. ) and drives the motor 22 based on the estimation result. Thereby, the rotational operation of the motor 22 is appropriately controlled. When the angular speed of the motor 22 is lowered to such an extent that a sufficient induced voltage is not generated within the motor 22 by the sensorless vector control, the drive control of the motor 22 is changed from the sensorless vector control to the open loop control. , and the rotational operation of the motor 22 is appropriately controlled by the current drawing method. With these controls, when an abnormality occurs in the position detection value while the motor 22 is rotating at a relatively high speed, the sensorless vector control and the open loop control are sequentially performed, and the rotation operation of the motor 22 is appropriately determined. It is possible to stop the motor 22 by gradually decelerating while controlling it.

In addition, when an abnormality occurs in the position detection value while the motor 22 is rotating at a relatively low speed, the sensorless vector control is not executed, and the motor 22 is decelerated and stopped only by the open loop control.

In addition, when an abnormality in the position detection value occurs, the change pattern of the position command value sent from the host controller 100 to stop the operation of the arm 2 is to simply decelerate and stop the driving of the motor 22 . It is not limited to a pattern. Depending on the structure of the arm 2, it may be possible to decelerate and stop the arm 2 along an appropriate trajectory according to the following pattern. That is, first, the driving of the motor 22 is stopped by the sensorless vector control and the open loop control. Immediately after that, the motor 22 is reversely rotated by open-loop control, acceleration and deceleration are performed in the reverse direction by sensorless vector control, and then the motor is decelerated and stopped by open-loop control.

<Configuration 4>

In addition to the structure 1 or 3, the structure 4 is provided with the structure which reduces the control loop gain of position speed control compared with detection position feedback control in sensorless vector control.

<Effect of configuration 4>

According to the configuration 4, the vibration of the motor 22 at the time of driving the motor by the sensorless vector control can be suppressed for the reason described below. That is, the position speed control loop in the detected position feedback control responds to the torque command value after the position command value and the torque command value (torque command signal) based on the position detection value are output from the position speed control unit 23 . It is a loop until the position detection value of one motor 22 is transmitted to the position speed control unit 23 . Further, in the position speed control loop in the sensorless vector control, the position command value and the torque command value based on the position detection value are output from the position speed control unit 23, and then the motor 22 in response to the torque command value. It is a loop until the signal of the position estimate value of is transmitted to the position velocity control unit 23 . In the sensorless vector control, when the accuracy of the estimation of the rotational position is not good, the frequency response characteristic of the position speed control loop is different from the frequency response characteristic of the position speed control loop of the detection position feedback control. The vibration of (22) will occur. In configuration 4, in the sensorless vector control, by lowering the open loop gain of the position speed control loop compared to the detection position feedback control, vibration of the motor 22 due to different frequency response characteristics of the position speed control loop can be suppressed. there is.

<Configuration 5>

Configuration 5 is a motor drive device 20 that controls driving of the motor 22 , and controls driving of the motor 22 by any of the motor control methods of Configurations 1 to 4.

<Operation and Effects of Configuration 5>

According to the configuration 5, by stopping the rotation of the motor 22 by any of the motor control methods of the configurations 1 to 4, it is possible to avoid the occurrence of an improper operation of the arm due to the emergency stop of the motor 22 . Accordingly, it is possible to decelerate and stop the arm 2 while moving along the target trajectory without colliding with devices or structures in the vicinity of the industrial robot 1 .

<Configuration 6>

Configuration 6 is a control method of the industrial robot 1 for changing the position of the arm 2 of the industrial robot 1 by individually controlling the driving of the plurality of motors 22 , in the plurality of motors 22 Each drive of is controlled by any motor control method of Configurations 1 to 4.

<Configuration 7>

Configuration 7 is the industrial robot 1 for changing the position of the arm 2 by individually controlling the driving of the plurality of motors 22 , and the respective driving of the plurality of motors 22 is performed according to the configuration 5 It is controlled by the motor drive device 20 .

<Operation effect of components 6 and 7>

In the configurations 6 and 7, the rotational operation of the motor 22 in which the position detection value is abnormal among the plurality of motors 22 serving as the drive source of the arm 2 is appropriately controlled by sensorless vector control or open loop control. While controlling, the rotational operation of the other motors 22 is appropriately controlled by the detection position feedback control to appropriately stop the rotation of all the motors 22 . According to this configuration, when an abnormality in the position detection value occurs in at least one of the plurality of motors 22 , the inappropriate operation of the arm 2 by emergency stop of all the motors 22 is prevented. occurrence can be avoided. Accordingly, it is possible to decelerate and stop the arm 2 while moving along the target trajectory without colliding with devices or structures in the vicinity of the industrial robot 1 .

As mentioned above, although preferred embodiment of this invention was described, this invention is not limited to embodiment, Various deformation|transformation and change are possible within the range of the summary. Embodiment is included in the scope and summary of the invention, and is included in the scope of the invention described in the claims and equivalents thereof.

1: Industrial Robot
2: Cancer
20: motor drive unit
21: control mode selection unit
22: motor
23: position speed control
24: Vector control DQ axis current command generation unit
25: first selector
26: current control unit
27: DQ inverse transform unit
28; PWM control
29: inverter
30: rotary encoder (rotational position detector)
31: current detection unit
32: second selector
33: vector control electric angle generator
34: third selector
35: location estimation unit
36: open loop control electric angle generator
37: open loop control DQ axis current command generation unit
38: encoder communication abnormality determination unit
39: DQ conversion unit
100: upper controller

Claims (8)

A motor comprising: a step of driving the motor by feedback control based on a rotational position command signal and a rotational position signal transmitted from a rotational position detector mounted on the motor; and a step of detecting the presence or absence of an abnormality in the rotational position signal. In the control method,
detecting a current flowing through the motor during driving;
When the abnormality of the rotation position signal is detected, the control method of the motor is based on a result of estimating the rotation position of the motor based on the detection result of the current from feedback control based on the rotation position signal and switching to sensorless vector control for driving the motor. A motor comprising: a step of driving the motor by feedback control based on a rotational position command signal and a rotational position signal transmitted from a rotational position detector mounted on the motor; and a step of detecting the presence or absence of an abnormality in the rotational position signal. In the control method,
and a step of switching the control method of the motor from feedback control based on the rotation position signal to open-loop control by a current drawing method when abnormality of the rotational position signal is detected. control method. The method according to claim 1, wherein when abnormality of the rotation position signal is detected, the motor is driven by the sensorless vector control in a predetermined high-speed angular velocity region, while in a low-speed angular velocity region lower than the high-speed angular velocity region, A motor control method, characterized in that the motor is driven by an open-loop control using a current drawing method. The motor control method according to claim 1, wherein in the sensorless vector control, the control loop gain of the position speed control is lowered as compared to the feedback control based on the rotation position signal. 4. The motor control method according to claim 3, wherein in the sensorless vector control, the control loop gain of the position speed control is lowered as compared with the feedback control based on the rotation position signal. It is a motor driving device that controls the driving of the motor,
A motor driving apparatus characterized by controlling the driving of the motor by the motor control method according to any one of claims 1 to 5. It is a control method of an industrial robot that changes the position of the arm of the industrial robot by individually controlling the driving of a plurality of motors,
The control method of the industrial robot characterized by controlling each drive in the some motor by the motor control method in any one of Claims 1-5. It is an industrial robot that changes the position of the arm by individually controlling the driving of multiple motors.
An industrial robot characterized in that each drive of a plurality of motors is controlled by the motor drive device according to claim 6 .

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