WO2006001480A1

WO2006001480A1 - Error judgment value setting method, motor control device, and actuator

Info

Publication number: WO2006001480A1
Application number: PCT/JP2005/011971
Authority: WO
Inventors: Kazuo Shoda; Yuki Nomura; Yoshifumi Nagato
Original assignee: Thk Co., Ltd.
Priority date: 2004-06-29
Filing date: 2005-06-29
Publication date: 2006-01-05
Also published as: JPWO2006001480A1

Abstract

A control unit of a motor driver automatically operates a linear motion device according to a given drive condition. An error judgment value setting unit samples the peak of the current supplied to the linear motor during the automatic operation. According to the peak value sampled, an error judgment value used for detecting an error of the linear motion device is set. For example, the error judgment value can be set at the peak value multiplied by about 1.2 to 1.4 and more preferably, by 1.25 to 1.3. Thus, it is possible to automatically set an error judgment value in accordance with the drive condition of the linear motion device.

Description

Specification

Abnormality judgment value setting method, motor control device, actuator

Technical field

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

Background art

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 controller). And then.

[0003] 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 (abnormal judgment value).

Disclosure of the invention

Problems to be solved by the invention

[0004] The current supplied to the motor depends on the driving conditions (speed, acceleration, load applied to the moving body, etc.) of the linear motion device. Therefore, the abnormality determination value should be set to an optimum value according to the driving conditions of the linear motion device.

However, at the time of product shipment, the user has no power to use the linear motion device under any conditions. Therefore, the upper limit (motor driver capacity) is set as the abnormality judgment value at the time of shipment. It must be set to. Therefore, in some cases, it may not be possible to accurately detect a linear motion device abnormality in which the difference between the actual supply current value and the abnormality judgment value is large.

. However, advanced skill is required to adjust the abnormality judgment value according to the driving conditions, and it is difficult for the user to set the optimum value.

[0006] 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. There is. Means for solving the problem

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.

[0008] The setting of the abnormality determination value may be performed 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 according to the given drive conditions. Then, the abnormality judgment value setting means samples the peak of the supply current or supply voltage to the motor at that time, and sets the abnormality judgment value used for detecting the abnormality of the linear motion device based on the sampled peak value. . For example, the abnormality judgment value should be set to about 1.2 to 1.4 times the peak value, preferably about 1.25-1.

[0009] 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.

[0010] It is preferable that the abnormality determination value setting process be executed under the same driving conditions as in the actual operation during the test operation before entering the actual operation.

[0011] 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 properly detect abnormalities in the linear motion device and prevent malfunctions and damages.

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

[0013] Therefore, in the present invention, the peak at the constant speed and the peak at the non-constant speed are sampled separately, and each peak value force abnormality determination value for the constant speed and abnormality determination for the non-constant speed are obtained. It is advisable to adopt a configuration that obtains values. As a result, abnormalities appropriate for both constant speed and non-constant speed Since the determination value is set, the accuracy and reliability of abnormality detection is improved.

[0014] It should be noted that the present invention can be understood as a motor control device having at least a part of the above means. The present invention can also be understood as an actuator comprising the motor control device and the linear motion device. Furthermore, the present invention can also be understood as an abnormality determination value setting method and 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.

The invention's effect

[0015] According to the present invention, it is possible to automatically set an appropriate abnormality determination value in accordance with the driving conditions of the linear motion device, and to reduce the load on the user and improve the accuracy of abnormality detection. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a configuration of an actuator according to an embodiment of the present invention. The actuator 1 according to this 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 that is slidable with respect to the base portion 20. In this 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 achieve a smooth linear motion.

A linear motor 23 is employed as the 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. By appropriately changing the magnetic force and polarity of the mover 23b by the motor driver 3, the position / velocity “acceleration” of the slider 21 can be controlled.

[0020] The position and speed of the slider 21 are detected by using a linear encoder 24 as position detecting means. A linear scale attached to the base 20 with the head 24b fixed to the slider 21. This is a mechanism for reading the rule 24a. 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 alternating current to the linear motor 23. The linear motor 23 operates according to this supplied current, and the slider 21 moves. The position / velocity information of the slider 21 is detected by the linear encoder 24 and sequentially input to the control unit 30. The control unit 30 feedback-controls the current supplied to the linear motor 23 based on the detection result, and causes the slider 21 to perform the desired 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 processing]

FIG. 3 is a flowchart showing the flow of the abnormality determination value setting process executed in the motor driver 3. This abnormality judgment 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.

[0025] In step S1, first, the control unit 30 drives the linear motion device 2 to start automatic operation. At this time, it is preferable to perform automatic operation 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 judgment value improves 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 supply current is larger at non-constant speed (acceleration and deceleration) than at constant speed. [0027] In step S2, the abnormality determination value setting unit 31 samples the peak (PI, P1 ', etc.) of the supply current during acceleration. In step S3, the peak at constant speed (P2, etc.) is sampled, and in step S4, the peak at deceleration (P3, P3 ', etc.) is sampled. Each sampling timing may be determined by the force recognized by the timing signal supplied from the control unit 30 and the changing force of the peak value.

[0028] In step S5, it is checked whether the above sampling process has been repeated N times (N is an integer of 1 or more). If it is less than N times, repeat steps S1 to S4.

In step S6, an average of peak values obtained by N sampling processes is obtained. Figure 5 shows the peak values during acceleration (black circles) and their average values (dashed lines). The average can be calculated using a simple average or a weighted average. It is also preferable to use a median (median) or maximum value that is not 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 calculating the average (or a similar value) of them.

[0030] Once the peak values (average values) at acceleration, constant speed, and deceleration are obtained, the abnormality determination value setting unit 31 uses the peak values as a reference for acceleration, constant speed, and deceleration. Abnormality judgment value for time 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 about L 3 times. Anomaly detection becomes more sensitive as the magnification is reduced, but false detection may increase. Conversely, increasing the magnification reduces the number of false detections, but decreases the accuracy of abnormality detection. The optimum magnification may be determined according to a specific embodiment.

[0031] 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).

[0032] (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 supply current to the linear motor 23 is monitored, and the value (amplitude) is compared with the abnormality determination value. At this time, The output unit 32 determines a driving state (aside from acceleration Z at constant speed Z deceleration) from a signal supplied from the control unit 30, and performs comparison using an abnormality determination value corresponding to the driving state. 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, the buzzer is sounded and the warning lamp is lit to notify the operator of the occurrence of an abnormality and prompt action.

[0034] 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. Therefore, it is possible to calculate an appropriate abnormality determination value according to the actual driving conditions, and to improve the accuracy of abnormality detection.

[0035] 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.

[0036] Further, 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.

[0037] 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.

[0038] For example, in the above embodiment, different abnormality judgment values are adopted for acceleration, constant speed, and deceleration, but there is not much difference in the amplitude of the supply current in each driving state. In some cases, a single abnormality determination value may be used, or the abnormality determination values during acceleration and deceleration may be shared. On the other hand, it is also preferable to classify the driving state more finely and adopt more than three abnormality judgment values.

[0039] 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, and for example, a constant is added to the peak value, or a predetermined function or table is used. You can also convert peak values.

[0040] 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. This allows the control program to be executed. It is possible to change the abnormality determination value to an appropriate value according to the program (driving condition).

In the above embodiment, the linear guide is used as the linear motion mechanism, but a ball screw, a roller screw, a ball spline, or a combination thereof can also be suitably used.

[0042] Further, a rotary servo motor instead of a linear motor may be employed as the driving mechanism for the linear motion mechanism, and a rotary encoder may be employed as the slider position detecting means instead of the linear encoder. Good.

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

Brief Description of Drawings

FIG. 1 is a diagram showing a configuration of an actuator according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a functional configuration of a motor driver.

FIG. 3 is a flowchart showing a flow of abnormality determination value setting processing.

FIG. 4 is a diagram showing an example of a waveform of a supply current.

FIG. 5 is a diagram showing a peak value during acceleration, an average value thereof, and an abnormality determination value.

FIG. 6 is a diagram for explaining abnormality detection processing.

Explanation of symbols

[0045] 1actuator

2 Linear motion device

3 Motor driver (motor control device)

20 Base part

21 Slider (moving object)

22 Linear guide

23 Linear motor

24 linear encoder

30 Control unit

31 Error judgment value setting section

32 Anomaly detector

Claims

The scope of the claims

[1] 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 peak of the supply current or supply voltage to the motor at that time, and setting the abnormality judgment value used for detecting the abnormality of the linear motion device based on the sampled peak value

An abnormality judgment value setting method for a linear motion device.

[2] The peak at constant speed and the peak at non-constant speed are sampled separately, and the peak value of each force is obtained.

The method for setting an abnormality judgment value for a linear motion device according to claim 1.

[3] Set the abnormality judgment value approximately 1.2 to 1.4 times the peak value.

The method for setting an abnormality judgment value for a linear motion device according to claim 1 or 2.

[4] control means for controlling the current or voltage supplied to the motor of the linear motion device;

When the control means automatically operates the linear motion device according to the given drive conditions!

An abnormality determination value setting means for sampling a peak of a supply current or supply voltage to the motor and setting an abnormality determination value based on the sampled peak value;

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:

[5] The abnormality judgment value setting means samples the peak at constant speed and the peak at non-constant speed separately, and each peak value force abnormality judgment value for constant speed and non-constant speed use Obtain the abnormal judgment value of

The motor control device according to claim 4.

[6] The abnormality judgment value setting means sets the abnormality judgment value about 1.2 to 1.4 times the peak value.

The motor control device according to claim 4 or 5.

[7] The motor control device according to claim 4, 5 or 6,

A linear motion device driven by the motor control device; Actuator with