JP2713659B2 - Safety device for servo control mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a servomotor based on a comparison result between an allowable torque current value set according to an operation pattern of a servomotor and an actual torque current value detected by the servomotor. The present invention relates to a safety device for a servo control mechanism that operates a control mechanism.

[Conventional technology]

FIG. 2 is a main part block circuit diagram of a conventional servo control mechanism. In the figure, (1) is an operation pattern determination unit that determines an operation pattern of the motor and outputs a torque current command (1a) corresponding to the pattern, and (2) is a voltage command of the motor based on the torque current command (1a). (3) a power amplifier for amplifying the voltage command input via the switch (4) and supplying the amplified voltage command to the motor (5); (6)
Is a current detector for detecting an actual torque current flowing to the motor (5), (7) is a torque current buffer for storing the detected actual torque current value, and (8) is an allowable value for storing a preset allowable torque current value. A torque current buffer (9) is a comparator that compares the allowable torque current with the actual torque current, outputs an abnormal signal (9a) according to the comparison result, and controls the switch (4) to shut off.

Next, the operation according to the above configuration will be described. When determining the operation pattern of the motor (5), the operation pattern determination unit (1) outputs a torque current command (1a) matching the pattern to the current control unit (2), and the current control unit (2) Create a voltage command for This voltage command is input to the voltage amplifier (3) via the switch (4) which is normally in the ON state, amplified to a predetermined voltage value, supplied to the motor (5), and used for motor control. When the motor starts, the torque current flowing to the motor (5) is the actual torque current value detected by the current detector (6), and the torque current buffer (7)
And is fed back to the current control unit (2) for current control.

On the other hand, the actual torque current stored in the torque current buffer (7) is compared with the allowable torque current value stored in the allowable torque current buffer (8) in the comparator (9), and the absolute value of the actual torque current is calculated. If the current value exceeds the allowable torque current value, an abnormal signal (9a) is output to the outside,
The switch (4) is turned off, the motor (5) is opened from the control unit, and the servo power is cut off.

[Problems to be solved by the invention]

As described above, in the conventional servo control mechanism, the permissible torque current is predetermined, and even if the torque current does not reach the above-mentioned fixed value or more even in an operation situation that does not originally require torque, the servo is controlled. The configuration was such that abnormality of the control mechanism could not be detected.

For this reason, when the servo control mechanism interferes with the outside during the operation at the maximum speed, the servo mechanism cannot be stopped immediately and there is a problem that the external peripheral device or the servo control mechanism is damaged. .

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a servo control mechanism safety device capable of setting an allowable torque current of a motor in real time.

[Means for solving the problem]

A safety device for a servo control mechanism according to the present invention includes an operation pattern determining unit that determines an operation pattern of a servo motor, a torque current command corresponding to the operation pattern, and an actual torque current detected by a current detector from the servo motor. A servo control mechanism having a control unit for generating a voltage command for the servo motor, a storage unit storing an allowable torque current value corresponding to each operation pattern, and an operation pattern determined by the operation pattern determination unit. An allowable torque current based on the determined allowable torque current, and an allowable torque current determining unit that reads out an optimal allowable torque current value from the storage unit in accordance with the determined allowable torque current; and the determined allowable torque current value and the actual torque current. And outputs a servo control mechanism operation inhibition signal when the actual torque current exceeds the allowable torque current value. In which the provided.

[Action]

According to the present invention, the allowable torque current according to each operation pattern of the motor is stored in advance in the allowable torque current buffer, and when the servo control mechanism operates, the allowable torque current determination unit determines the allowable torque current determined according to the operation pattern. Read the optimal allowable torque current value from the storage unit in accordance with, input this allowable torque current value to a comparator, compare the actual torque current output with the operation of the motor in this comparator in real time, and When the absolute value exceeds the allowable torque current, an abnormal signal is output to prevent the servo control mechanism from starting.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block circuit diagram of a safety device for a servo control mechanism in the present embodiment. In the figure, the same reference numerals as those in FIG. 1 indicate the same or corresponding parts.

In the figure, (10) is an allowable torque current determination unit that determines an allowable torque current value according to the operation state signal (1b) output from the operation pattern determination unit (1), and (11) is preset according to each operation pattern. A current value buffer storing each allowable torque current value, and (12) a switch for switching and inputting a predetermined allowable torque current value to the allowable torque current buffer (8a) in accordance with the operation pattern determination from the current value buffer (11). .

Next, the operation of this embodiment according to the above configuration will be described. Since the motor control method, the actual torque current value detection, and the abnormality detection of the servo control mechanism based on the actual torque current value are the same as those in the related art, detailed description thereof is omitted.
The description will proceed from the allowable torque current setting method according to the abnormality detection method.

First, each allowable torque current value is stored in the current value buffer (11) according to each operation pattern of the motor. Then, the operation pattern determination section (1) newly generates an operation state signal (1b). When this signal is stopped, operation starts,
This signal is used to determine whether the vehicle is accelerating, operating at a constant speed, decelerating, or completing the operation. Based on the signal (1b), the permissible torque current determination unit (10) selects an optimum one from N permissible torque current values registered in the current value buffer (11) in advance, and selects a switch (12). ) To set data in the allowable torque current buffer (8a). This setting is performed while the servo control is effective at each time. Moreover, this setting is performed even when there is no movement command. When the data is set in the allowable torque current buffer (8a), the allowable torque current value based on the data is compared with the actual torque current written in the torque current buffer (7) by the comparator (9). When the torque current exceeds the set allowable torque current value, the switch (4) is cut off and the motor power is cut off as in the case of outputting the abnormal signal (9a) to the outside as in the conventional case.

〔The invention's effect〕

As described above, according to the present invention, the allowable torque current value is determined based on the operation pattern determined by the storage unit storing the allowable torque current value corresponding to each operation pattern and the operation pattern determined by the operation pattern determination unit. And comparing the determined allowable torque current value with the actual torque current value, and comparing the actual torque current value with the allowable torque current determining unit that reads out the optimal allowable torque current value from the storage unit according to the determined allowable torque current. When the current exceeds the allowable torque current, a comparator is provided to output an operation inhibition signal of the servo control mechanism, so that in any operation mode of the servo control mechanism, the abnormal state of the servo control mechanism can be minimized in the shortest possible time. Detect
This has the effect of stopping the servo control mechanism and improving safety.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram showing one embodiment of a servo control mechanism safety device according to the present invention, and FIG. 2 is a block diagram of a main part of a conventional servo control mechanism. In the figure, (1) is an operation pattern determination unit, (1a) is a torque current command, (1b) is an operation state signal, (2) is a current control unit,
(3) is a power amplifier, (4) and (12) are switches,
(5) is a motor, (6) is a current detector, (7) is a torque current buffer, (8a) is an allowable torque current buffer,
(9) is a comparator, (9a) is an abnormal signal, (10) is an allowable torque current determination unit, and (11) is a current value buffer. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

(57) [Claims] An operation pattern determining unit for determining an operation pattern of a servomotor, and a voltage command for the servomotor is created from a torque current command according to the operation pattern and an actual torque current detected by a current detector from the servomotor. A servo control mechanism comprising: a storage unit storing an allowable torque current value corresponding to each operation pattern; and a storage unit storing an allowable torque current value corresponding to each operation pattern, based on an operation state signal output from the operation pattern determination unit. An allowable torque current determining unit that determines and reads an allowable torque current value, and compares the determined and read allowable torque current value with the actual torque current value, and the actual torque current exceeds the allowable torque current value. And a comparator for outputting a signal for inhibiting operation of the servo control mechanism.