JPWO2006001480A1 - Abnormality judgment value setting method, motor control device, actuator - Google Patents

Abstract

The controller of the motor driver automatically operates the linear motion device in accordance with the given driving conditions. Then, the abnormality determination value setting unit samples the peak of the current supplied to the linear motor at that time, and sets the abnormality determination value used for detecting the abnormality of the linear motion device on the basis of the sampled peak value. For example, the abnormality determination value may be set to about 1.2 to 1.4 times the peak value, preferably about 1.25 to 1.3 times. Thereby, it is possible to automatically set an appropriate abnormality determination value in accordance with the driving conditions of the linear motion device.

Description

  The present invention relates to a technique for detecting an abnormality of a linear motion device on a motor control device side.

  Conventionally, linear motion devices such as linear guides and ball screws have been widely used. In this type of linear motion device, linear motors and servo motors are used to drive the moving body, and the position, speed, and acceleration of the moving body are controlled by changing the current supplied from the motor driver (motor control device). Yes.

  If foreign objects fall into the moving path of the moving body or chips or dust enter the ball circulation path of the linear motion device, smooth movement of the moving body is hindered, causing malfunction or failure. Therefore, normally, an overload alarm function is provided in the motor driver so that a warning is issued when the supply current exceeds a predetermined alarm value (abnormality determination value).

  The current supplied to the motor depends on the driving conditions (speed, acceleration, load on the moving body, etc.) of the linear motion device. Therefore, normally, the abnormality determination value should also be set to an optimum value according to the driving conditions of the linear motion device.

  However, at the stage of product shipment, since the user does not know under what conditions the linear motion device is used, it is necessary to set the upper limit value (motor driver capacity) as the factory setting of the abnormality determination value. Absent. Therefore, in some cases, the difference between the actual supply current value and the abnormality determination value is large, and the abnormality of the linear motion device may not be detected accurately. However, advanced skills are required to adjust the abnormality determination value according to the driving conditions, and it is difficult for the user to set the optimal value.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a technique for automatically setting an appropriate abnormality determination value in accordance with the drive condition of the linear motion device. .

  In order to achieve the above object, in the present invention, the linear motion device is operated, and the abnormality determination value is set based on the supply current to the motor or the peak of the supply current at that time.

  The abnormality determination value may be set by a motor control device that controls the motor of the linear motion device. That is, first, the control means for controlling the current or voltage supplied to the motor of the linear motion device automatically operates the linear motion device in accordance with the given drive conditions. Then, the abnormality determination value setting means samples the peak of the supply current or supply voltage to the motor at that time, and sets the abnormality determination value used for detecting the abnormality of the linear motion device on the basis of the sampled peak value. For example, the abnormality determination value may be set to about 1.2 to 1.4 times the peak value, preferably about 1.25 to 1.3 times.

  The peak value represents the load actually applied to the motor. Therefore, by using the value as a reference, it is possible to calculate an appropriate abnormality determination value according to the actual driving condition of the linear motion device. In addition, since each process is automatically executed without bothering the user, it is possible to simplify the setting of the abnormality determination value and save labor.

  The abnormality determination value setting process is preferably executed under substantially the same driving conditions as in the actual operation during the trial operation before the actual operation.

  During actual operation, the abnormality detection means of the motor control device may detect an abnormality of the linear motion device by comparing the supply current or supply voltage to the motor with the abnormality determination value. As a result, it is possible to appropriately detect an abnormality in the linear motion device and prevent a failure or breakage.

  By the way, normally, the load (that is, the amplitude of the supply current or the supply voltage) applied to the motor is larger at non-constant speed (acceleration or deceleration) than at constant speed. Therefore, when the abnormality determination value is set based on the peak value at non-constant speed, the abnormality detection accuracy at constant speed may be reduced. On the other hand, when the peak value at the constant speed is used as a reference, erroneous determination may occur frequently at the non-constant speed.

  Therefore, in the present invention, the peak at the constant speed and the peak at the non-constant speed are separately sampled, and the abnormality determination value for the constant speed and the abnormality determination value for the non-constant speed are obtained from each peak value. The configuration should be adopted. Thereby, since an appropriate abnormality determination value is set for each of the constant speed and the non-constant speed, the accuracy and reliability of abnormality detection are improved.

  The present invention can be understood as a motor control device having at least a part of the above means. Moreover, this invention can also be grasped | ascertained as an actuator provided with the motor control apparatus and a linear motion apparatus. Furthermore, the present invention can also be understood as an abnormality determination value setting method or control method for a linear motion device that includes at least a part of the above processing. Each of the above means and processes can be combined with each other as much as possible to constitute the present invention.

  According to the present invention, it is possible to automatically set an appropriate abnormality determination value according to the driving condition of the linear motion device, and to reduce the load on the user and improve the accuracy of abnormality detection.

  Exemplary embodiments of the present invention will be described in detail below with reference to the drawings.

  FIG. 1 shows a configuration of an actuator according to an embodiment of the present invention. The actuator 1 of the present embodiment is a linear motor actuator that drives a moving body with a linear motor, and includes a linear motion device 2 and a motor driver (motor control device) 3 that controls the linear motion device 2.

  The linear motion device 2 generally includes a base portion 20 and a slider (moving body) 21 provided slidably with respect to the base portion 20. In the present embodiment, two linear guides 22 are employed as the linear motion mechanism of the slider 21, two rails 22 a are provided on both sides of the base portion 20, and two blocks 22 b are attached to the back surface of the slider 21. A plurality of rolling elements (balls or rollers) are interposed between the rail 22a and the block 22b, and when the slider 21 moves, the rolling elements roll to realize a smooth linear motion.

  A linear motor 23 is employed as a driving means for the slider 21. A permanent magnet magnet plate 23 a is provided on the bottom surface of the base portion 20, and a mover 23 b is fixed to the lower portion of the slider 21. The position, speed, and acceleration of the slider 21 can be controlled by appropriately changing the magnetic force and polarity of the mover 23 b by the motor driver 3.

  The position / speed of the slider 21 is detected by using a linear encoder 24 as position detecting means. This is a mechanism for reading the linear scale 24 a attached to the base portion 20 with the head 24 b fixed to the slider 21. The detection result of the linear encoder 24 is input to the motor driver 3 and used for feedback control of the linear motor 23.

  FIG. 2 is a block diagram showing a functional configuration of the motor driver 3. The motor driver 3 includes a control unit 30, an abnormality determination value setting unit 31, and an abnormality detection unit 32.

  The control unit 30 performs frequency and amplitude modulation of the currents of the U, V, and W phases according to the set control program, and supplies the three-phase AC current to the linear motor 23. The linear motor 23 operates according to this supply current, and the slider 21 moves. The position / velocity information of the slider 21 is detected by the linear encoder 24 and is sequentially input to the control unit 30. The control unit 30 feedback-controls the supply current to the linear motor 23 based on the detection result, and causes the slider 21 to perform an intended motion.

  The abnormality determination value setting unit 31 is a part that automatically calculates and sets an abnormality determination value. The abnormality determination value obtained here is transferred to the abnormality detection unit 32 and used for abnormality detection of the linear motion device 2. Hereinafter, the abnormality determination value setting process and the linear motion apparatus abnormality detection process will be described in detail.

(Abnormal judgment value setting process)
FIG. 3 is a flowchart showing a flow of abnormality determination value setting processing executed in the motor driver 3. This abnormality determination value setting process is executed at the time of trial operation before entering the actual operation, such as when the linear motion device 2 is installed. It is also preferable to update the abnormality determination value not only at the time of installation but also periodically.

  In step S1, the control unit 30 first drives the linear motion device 2 to start automatic operation. At this time, it is preferable to perform automatic driving under substantially the same driving conditions (speed, acceleration, load applied to the slider 21, etc.) as in actual operation. This is because the reliability of the calculated abnormality determination value is improved as the conditions are closer to actual operation.

  FIG. 4 shows an example of the waveform of the current supplied to the linear motor 23. This figure is a waveform related to one drive, and a series of control is performed in which the slider 21 in a stationary state is accelerated, moved at a constant speed when it reaches a predetermined speed, and then decelerated and stopped. Represents. It can be seen that the amplitude of the supplied current is larger at non-constant speed (acceleration and deceleration) than at constant speed.

  In step S2, the abnormality determination value setting unit 31 samples the peak (P1, P1 ′, etc.) of the supply current during acceleration. In step S3, the peak at constant speed (P2, P2 ', etc.) is sampled, and in step S4, the peak at deceleration (P3, P3', etc.) is sampled. Each sampling timing may be recognized by a timing signal supplied from the control unit 30 or determined from a change in peak value.

  In step S5, it is checked whether the sampling process has been repeated N times (N is an integer of 1 or more). If it is less than N times, the processes in steps S1 to S4 are repeated.

  In step S6, an average of peak values obtained by N sampling processes is obtained. FIG. 5 shows peak values during acceleration (black circles) and average values thereof (broken lines). For calculating the average, a simple average or a weighted average may be used. It is also preferable to use a median or maximum value instead of an average value, or estimate a peak value by a statistical method. Thus, the reliability of the peak value can be improved by performing sampling a plurality of times and obtaining an average (or a value similar thereto).

  When the peak value (average value) at the time of acceleration, constant speed, and deceleration is obtained, the abnormality determination value setting unit 31 uses the peak values as a reference for acceleration, constant speed, and deceleration. An abnormality determination value is calculated (step S7). Here, as shown in FIG. 5, a value obtained by simply multiplying the peak value by a constant is adopted as the abnormality determination value. The magnification at this time is about 1.2 to 1.4 times, preferably about 1.25 to 1.3 times. Anomaly detection becomes more sensitive as the magnification is reduced, but false detection may increase. Conversely, when the magnification is increased, false detection is reduced, but the accuracy of abnormality detection is reduced. The optimum magnification may be determined according to a specific embodiment.

  When the abnormality determination values are obtained, they are stored in the nonvolatile memory, and the abnormality determination value setting process is terminated (step S8).

(Abnormality detection processing)
FIG. 6 is a diagram for explaining the abnormality detection process in the abnormality detection unit 32. As shown in the figure, the abnormality detection unit 32 reads the abnormality determination values for acceleration, constant speed, and deceleration from the nonvolatile memory and holds them as threshold values. Then, the current supplied to the linear motor 23 is monitored, and the value (amplitude) is compared with the abnormality determination value. At this time, the abnormality detection unit 32 determines a driving state (acceleration / constant speed / deceleration) from a signal supplied from the control unit 30, and compares the determination using an abnormality determination value corresponding to the driving state. I do. Then, as shown in FIG. 6, when the value of the supply current reaches the abnormality determination value, it is determined that some abnormality has occurred in the linear motion device 2.

  When an abnormality is detected, the abnormality detection unit 32 sends an abnormality detection signal to the control unit 30 to interrupt the control being executed. In addition, a buzzer is sounded and a warning lamp is lit to notify the operator of the occurrence of an abnormality and prompt prompt action.

  According to the configuration of the present embodiment described above, the linear motion device 2 is actually operated, and the abnormality determination value is calculated based on the peak of the supply current observed there. It is possible to calculate an appropriate abnormality determination value according to the driving conditions, and consequently improve the accuracy of abnormality detection.

  In addition, since each process is automatically executed without bothering the user, it is possible to simplify the setting of the abnormality determination value and save labor.

  Furthermore, since different abnormality determination values are adopted for acceleration, constant speed, and deceleration, the accuracy and reliability of abnormality detection are improved in each driving state.

  The above embodiment is merely an example of the present invention. The scope of the present invention is not limited to the above embodiment, and various modifications can be made within the scope of the technical idea.

  For example, in the above embodiment, different abnormality determination values are adopted for each of acceleration, constant speed, and deceleration. However, when there is no significant difference in the amplitude of the supply current in each driving state, a single abnormality determination is performed. A value may be used, or an abnormality determination value during acceleration and deceleration may be shared. Conversely, it is also preferable to classify the driving state more finely and employ more than three abnormality determination values.

  In addition, the calculation method of the abnormality determination value is not limited to the method of multiplying the peak value by a constant as in the above embodiment. For example, the peak value can be calculated by adding a constant to the peak value or using a predetermined function or table. It may be a method of conversion.

  When a plurality of control programs can be set in the motor control device, it is preferable that an abnormality determination value can be set for each control program. As a result, the abnormality determination value can be changed to an appropriate value in accordance with the control program (drive condition) to be executed.

  Moreover, although the linear guide was employ | adopted as a linear motion mechanism in the said embodiment, a ball screw, a roller screw, a ball spline, or those combinations can also be employ | adopted suitably besides these.

  Further, a rotary servo motor instead of a linear motor may be employed as the drive unit for the linear motion mechanism, and a rotary encoder may be employed as the slider position detection unit instead of the linear encoder.

  In the above embodiment, the waveform of the supply current is monitored. However, when the motor is voltage-controlled, it is preferable to detect the abnormality by monitoring the waveform of the supply voltage.

The figure which shows the structure of the actuator which concerns on one Embodiment of this invention. The block diagram which shows the function structure of a motor driver. The flowchart which shows the flow of an abnormality determination value setting process. The figure which shows an example of the waveform of supply current. The figure which shows the peak value at the time of acceleration, the average value, and an abnormality determination value. The figure for demonstrating abnormality detection processing.

Explanation of symbols

1 Actuator 2 Linear motion device 3 Motor driver (motor control device)
20 Base part 21 Slider (moving body)
22 Linear Guide 23 Linear Motor 24 Linear Encoder 30 Control Unit 31 Abnormality Determination Value Setting Unit 32 Abnormality Detection Unit

Claims (7)

A motor control device that controls the motor of the linear motion device
The linear motion device is automatically operated according to the given drive conditions,
Sampling the supply current or supply voltage peak to the motor at that time,
An abnormality determination value setting method for a linear motion device, wherein an abnormality determination value used for detecting an abnormality of the linear motion device is set based on a sampled peak value. 2. The direct measurement according to claim 1, wherein the peak at constant speed and the peak at non-constant speed are sampled separately, and the abnormality determination value for constant speed and the abnormality determination value for non-constant speed are obtained from the respective peak values. An abnormality judgment value setting method for a moving device. 3. The abnormality determination value setting method for a linear motion device according to claim 1, wherein the abnormality determination value is set to about 1.2 to 1.4 times the peak value. Control means for controlling the current or voltage supplied to the motor of the linear motion device;
When the linear motion device is automatically operated in accordance with the given drive conditions, the control means samples the peak of the supply current or supply voltage to the motor, and sets the abnormality judgment value based on the sampled peak value An abnormality judgment value setting means to perform,
An abnormality detection means for detecting an abnormality of the linear motion device by comparing the supply current or supply voltage to the motor and the abnormality determination value;
A motor control device comprising: The abnormality determination value setting means samples the peak at the constant speed and the peak at the non-constant speed separately, and from each peak value, the abnormality determination value for the constant speed and the abnormality determination value for the non-constant speed The motor control device according to claim 4. The motor control device according to claim 4 or 5, wherein the abnormality determination value setting means sets an abnormality determination value at about 1.2 to 1.4 times the peak value. The motor control device according to claim 4, 5 or 6,
A linear motion device driven by the motor control device;
An actuator comprising:

Images