JP2005080332A - Method for detecting abnormal following of motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To quickly and easily detect such abnormality as motor or machine does not follow under the command such as for position or speed. <P>SOLUTION: A control unit for driving a motor comprises a speed estimating means for calculating speed from the model mode. It compares the estimated speed based on the model with a motor speed during a acceleration/deceleration action, while detects follow-up abnormality based on deviation between the motor speed and position during a constant speed action. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for detecting an abnormality in a control device for driving a motor, such as when a motor or machine in a control system does not follow a position command or a speed command.

Conventionally, when the motor does not follow the command such as position and speed as shown in FIG. 7, for example, in the case of position control, the position deviation overflow detecting means 24 detects the following abnormality. Further, as in Patent Document 1, when the deviation between the position command obtained by passing the low-pass filter and the position feedback exceeds a certain level, it is determined to be abnormal.
JP 2001-159918 A

In the conventional technique, when the tracking error is detected by the position deviation overflow detection means 24, there is a problem that the detection cannot be performed unless a command is given until the motor reaches the overflow detection level after being started. In addition, even if the load became heavy or crashed for some reason, it could not be detected immediately. Further, even in the case of Patent Document 1, there is an influence of load, inertia, and the like, which is different from the actual movement, so that there is a problem that the tracking abnormality detection level cannot be lowered and the tracking abnormality cannot be detected immediately. In addition, if performed accurately, the time constant must be matched to the actual motor or machine, so it was necessary to measure them.
Therefore, an object of the present invention is to quickly and easily detect an abnormality when a motor or a machine does not follow a command such as a position and a speed.

In order to solve the above-mentioned problem, the control device for driving the motor includes speed estimation means for calculating the speed from the model of the load, and the difference between the speed from the speed estimation means and the actual speed is larger than a predetermined value In addition, it is determined that the motor does not follow the speed command or the like.
Further, when the difference between the speed from the speed estimation means and the actual speed is larger than a predetermined value during the acceleration / deceleration operation, and when the position deviation is larger than the predetermined value during the constant speed operation, the motor performs a speed command or the like. It is determined that it is not following.
Furthermore, the motor is operated when the difference between the speed from the speed estimation means and the actual speed is larger than a predetermined value during acceleration / deceleration operation, and when the differential value of the position deviation is larger than a predetermined value during constant speed operation. It is determined that the speed command is not followed.
Further, the speed estimation means calculates the speed using an observer instead of calculating the speed from the load model.

  According to the present invention, the tracking error is detected from the model speed and the motor speed when the position deviation is large, and the tracking error is detected from the deviation at the constant speed operation where the position deviation is small. It is possible to quickly detect a tracking error. Further, even when the load becomes heavy or a collision occurs, it is possible to detect a follow-up abnormality without damaging the machine.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

In FIG. 1, 1 is a tracking abnormality detecting means, 2 is a microcomputer, 3 is a current amplifier, 4 is a base drive circuit, 5 is a power transistor module, and 6 is a motor. The operation of the circuit configured as described above will be described with reference to the control block diagram of FIG. 2, the timing diagram of FIG. 4, and the flowchart of FIG.
First, in FIG. 1, the microcomputer 2 receives commands such as position and speed from an external controller or the like. For example, in the case of a speed command, speed control is performed, and the motor is controlled by driving the power transistor 5 through the base drive drive circuit 4 with the output current command or current control output. Here, in addition to the normal control, the microcomputer 2 calculates the estimated speed ωo of the model from the torque τ as shown in the block diagram of FIG. The follow-up abnormality detecting means 1 detects an abnormality at a certain level or more between the estimated speed of the model and the motor speed as shown in FIG. 4 from the stop state to the start of the motor. The abnormality detection value is slightly larger than the delay between the command and the motor (or five times the level during normal operation). Next, when the steady speed is reached, the position deviation becomes substantially constant as shown in FIG. 4 and is detected from the position deviation which is the difference between the position command and the motor position. The detected value is a value that is slightly larger than the deviation determined from the position loop gain and speed.

  In this way, the start-up with a large position deviation is detected from the speed and the estimated speed, and the steady-state speed is detected from the position deviation with a small position deviation. The specific procedure for detecting a tracking error is as follows. First, the estimated speed is calculated from the torque command and the motor model as in process 1 of FIG. Next, the speed difference is calculated by subtracting the speed feedback from the estimated speed as in process 2 of FIG. If the speed difference is equal to or greater than a certain detection level as in process 3 of FIG. As the detection level, the detection value as described above is used. If it is normal, it is confirmed in step 4 of FIG. If acceleration / deceleration is in progress, the process ends. If the speed is constant, it is checked in step 5 of FIG. The position deviation ε at constant speed F with position gain Kp is

    ε = F / Kp

Therefore, the detection level may be a value larger than this value. When the position deviation is large, it is determined that the tracking is abnormal, and when it is small, the normal end is performed. FIG. 6 is a waveform of normal speed, estimated speed, position deviation, and difference between estimated speed and speed on a certain machine.
It can be seen that the position deviation is not constant at the time of startup, and the difference between the estimated speed and the speed is small. Here, when a follow-up abnormality is detected by a position deviation according to the conventional method, even if it is as small as 10,000 command units, it can be detected only at point B and a large movement command is issued. In the case of the present invention, even if the deviation is as large as about five times the normal deviation, it can be detected at the point A, so that an abnormality can be detected immediately.

As another embodiment, as shown in the control block diagram of FIG. 3, an example in which a tracking abnormality is similarly detected using the estimated speed ωob of the observer is shown. In the control block diagram of FIG. 3, 12 is the speed control, 13 is the motor, 14 is the load inertia of the observer, 15 is the gain of the observer's speed control, 16 is the integral, 17 is the integral of the observer's speed control, and 18 is the observer's integral. The whole. Similarly, if it is observed that ωob-ω exceeds a certain detection level at the time of activation, a tracking abnormality is detected.
Further, the simple estimation of the block diagram of FIG. 2 was performed to estimate the speed. However, if the details of the machine are known, a detailed model or speed may be used in consideration of the load condition and the like.

  By the above means, the tracking error is detected from the model speed when starting with a large position deviation, and the tracking error is detected from the deviation when operating at a constant speed with a small position deviation. Can do. Further, it is possible to detect an abnormality when the load becomes heavy or the vehicle collides.

It is a block diagram of the specific Example of this invention. It is a control block diagram of the present invention. It is a control block diagram of another Example of this invention. It is an operation | movement timing diagram in this invention. It is a schematic flowchart which extracts the limit gain of this invention. It is a waveform of speed, estimated speed, position deviation, estimated speed and speed difference on a certain machine. It is a block diagram of the conventional Example.

Explanation of symbols

1 Tracking abnormality detection means 2, 19 Microcomputer 3, 20 Current amplifier 4, 21 Base drive circuit 5, 22 Power transistor module 6, 9, 13, 23 Motor 7 Position loop gain 8 Proportional integral compensation (for speed control)
10, 16 Integral 11 Motor model 12 for calculating the model 12 Speed control 14 Observer load inertia 15 Observer speed control gain 17 Observer speed control integral 18 Observer overall 24 Position deviation overflow detection means

Claims (4)

  The control device for driving the motor includes speed estimation means for calculating a speed from a load model, and when the difference between the speed from the speed estimation means and the actual speed is larger than a predetermined value, the motor is a speed command or the like. Motor abnormality detection method for determining that the motor is not following.   2. The motor follow-up abnormality detection method according to claim 1, wherein the position deviation is predetermined during constant speed operation when the difference between the speed from the speed estimation means and the actual speed is greater than a predetermined value during acceleration / deceleration operation. Motor follow-up abnormality detection method for determining that the motor is not following the speed command or the like when the value is larger than the value of.   2. The motor follow-up abnormality detection method according to claim 1, wherein, during acceleration / deceleration operation, when the difference between the speed from the speed estimation means and the actual speed is larger than a predetermined value, the differential of position deviation during constant speed operation. A follow-up abnormality detection method for a motor that determines that the motor does not follow a speed command or the like when the value is larger than a predetermined value.   4. The motor follow-up abnormality detection method according to claim 1, wherein the speed estimator calculates a speed using an observer instead of calculating a speed from the load model. Method.

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