JP3696634B2 - Press machine with dregs up detection mechanism - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a press working machine with a dregs up detection mechanism for detecting an abnormal load applied to a servo system during dreg up.
[0002]
[Prior art]
Conventionally, there has been a problem that when a dregs rise occurs in a press machine and a dregs comes out on the upper surface of the die, the workpiece collides with the dregs and becomes a disturbance to the servo system. To detect this disturbance and stop the rotating shaft,
(1) Excessive error detection during movement
(2) Servo amplifier overload was detected.
[0003]
[Problems to be solved by the invention]
However, excessive detection of error ε during movement is
ε = V / G (1)
For example, when the velocity V = 50 (m / min) and the acceleration G = 30 (1 / s), the error ε is about 27.8 mm. If the margin is doubled, the error ε is about 56 mm, and an alarm can be generated if an error of 56 mm or more occurs during movement. However, when the moving distance is about 56 mm or less, there is a problem that an excessive error cannot be detected.
[0004]
In the case of amplifier overload detection, if the rotation axis does not move with the maximum torque that can be output by the servo amplifier, an alarm is generated when overload detection is performed. However, when the maximum torque of the servo amplifier is small, an alarm occurs due to overloading. However, when the servo amplifier is large, there is a problem that the machine is forcibly moved and damaged.
[0005]
An object of the present invention is to provide a press machine with a dregs up detection mechanism that can detect an abnormality in a servo system due to dregs up and prevent damage to the machine in order to improve the above problems. There is to do.
[0006]
[Means for Solving the Problems]
The present invention has been made in view of the above-described problems. The invention according to claim 1 is a press machine having a servo mechanism for moving a work piece to a press work position. There is a dregs up detection mechanism that detects an abnormal load that occurs when a dregs collides with the servo mechanism, and the descent up detection mechanism includes a calculation unit that calculates a target position and a disturbance maximum value, a position control unit, The position control unit compares a target position with a current position and generates a target speed from an error amount; a filter circuit that converts the target speed into a current command; and A first conversion circuit that converts the actual speed into a current position in consideration of a torque constant and an inertia value; and a second conversion circuit that converts the actual speed into a current position, and further includes the current command and the actual speed. A press with an upsurge detection mechanism that has a disturbance estimation unit that recognizes an estimated disturbance torque and a comparison unit that recognizes the disturbance torque by monitoring current and detects when the disturbance torque exceeds the maximum disturbance torque It is a processing machine.
The invention according to claim 2 is characterized in that the descent detection mechanism detects a torque change due to a disturbance, a speed change due to a disturbance, or a change in an error amount due to a disturbance by comparing with a normal waveform at a rising position. This is a press machine with a dregs up detection mechanism.
[0007]
【Example】
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0008]
FIG. 5 is an explanatory view of a main part of a press machine in which the present invention is implemented. In the figure, reference numeral 11 denotes a carriage in the X-axis direction of the press machine. The workpiece W is clamped by two workpiece clamps 12 and moved in the X-axis direction, and the workpiece W is punched by a punch 13 and a die 13 (not shown). do. At this time, when the punching waste a comes out on the upper surface of the die 13, the moving workpiece W collides with the punching waste a, resulting in an abnormal disturbance for the servo system.
[0009]
Therefore, a detection mechanism for detecting the gas rising described below is provided.
[0010]
FIG. 1 is a block diagram of a gas rising detection mechanism according to an embodiment of the present invention. In the figure, the data input unit 1 inputs the maximum allowable disturbance in a mechanical system (not shown) to the calculation unit 2. The maximum value is input to the program control unit (PLC) 7 and the memory unit 8.
[0011]
The target position θr and the maximum disturbance level Tr calculated by the calculation unit 2 are input to the position control unit 6 via the interface unit 9. The target position θr is compared with the current position θf, and the error amount θe is converted to the target speed ωr by the position loop gain circuit K1.
[0012]
This target speed ωr is converted into a current command i by a filter circuit k2 · (1 + T1 · S) / T1 · S having a speed loop gain k2, and the torque constant kt is taken into consideration for this current command i, and (motor + load ) The actual speed ωf is converted by the conversion circuit 1 / J · S in which the inertia J is considered. The actual speed ωf is converted to the current position θf by the conversion circuit 1 / S and output to a servo system (not shown).
[0013]
The disturbance estimator 4 compares the value obtained by converting the current command i with the torque constant estimated value ktn and the value obtained by converting the actual speed ωf with the (motor + load) estimated inertia value Jn S, and estimates the estimated disturbance torque T. 'L is recognized and output to the comparison unit 3 through the primary filter circuit 1 / (1 + T2 S).
[0014]
When the estimated disturbance torque T′L input to the comparison unit 3 exceeds the set maximum disturbance level Tr, the estimated disturbance torque T′L is output to the alarm detection unit 5 to turn off the servo system (not shown) and to receive the information. This is transmitted to the program control unit (PLC) 7.
[0015]
Since the disturbance torque is detected as described above, an abnormal load is detected regardless of acceleration or constant speed, and damage to the machine is prevented.
[0016]
FIG. 2 is a waveform diagram at the time of dregs rise according to FIG. In the figure, a minute speed change ω0 due to the error amount of the target speed ωr as shown in FIG. 9A or a torque change t0 that does not apply to the current limiter of torque kt · i + TL as shown in FIG. Compared with the motor torque KtM · i as shown in FIG. 10C, it is possible to detect an abnormality in the estimated disturbance torque T′L as shown in FIG.
[0017]
FIG. 3 shows a waveform diagram of another embodiment of the present invention. In the figure, it is possible to detect a honey climb by detecting a change in speed at the honey climb position θ0 of the waveform of the current position θf (FIG. (B)) with respect to the waveform of the target position θr (FIG. (A)).
[0018]
FIG. 4 shows a waveform diagram of still another embodiment of the present invention. In the figure, by detecting a change in the error amount θeo (FIG. (C)) at the honey upstream position θ0 of the waveform of the current position θf (FIG. (B)) with respect to the waveform of the target position θr (FIG. (A)), Can be detected.
[0019]
As described above, the servo system current is monitored, the theoretical value necessary for acceleration / deceleration is subtracted from that value, the disturbance torque is recognized, and the torque is compared with the preset maximum disturbance level. This is an algorithm that detects an abnormal load when dipping up using an algorithm that generates an error when the value exceeds.
[0020]
In addition, this invention is not limited to the said Example, It is possible to implement in another aspect by making an appropriate design change.
[0021]
【The invention's effect】
As is apparent from the above description, the press working machine with a dregs detection mechanism according to the present invention detects an abnormal load generated when a dregs collides with the servo mechanism when the dregs of the workpiece is on the upper surface of the die. The problem of the conventional technology can be easily solved by detecting a torque change due to disturbance, detecting a speed change due to disturbance, or detecting a change in error amount due to disturbance. In addition, it is possible to detect an abnormality in the servo system due to the occurrence of dregling, and prevent damage to the machine.
[0022]
The servo system current is monitored, and the theoretical value necessary for acceleration / deceleration is subtracted from that value in consideration of inertia, the disturbance torque is recognized, the torque, the preset maximum disturbance level, and the waveform rising position In comparison, it is possible to detect a minute abnormal load at the time of dregs up using an algorithm that an error occurs when the value is exceeded.
[Brief description of the drawings]
FIG. 1 is a block diagram of a gas rising detection mechanism according to an embodiment of the present invention.
FIG. 2 is a waveform diagram at the time of dipping up according to FIG. 1;
FIG. 3 is a waveform diagram of another embodiment of the present invention.
FIG. 4 is a waveform diagram of still another embodiment of the present invention.
FIG. 5 is an explanatory diagram of a main part of a press machine in which the present invention is implemented.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Data input part 2 Computation part 3 Comparison part 4 Disturbance estimation part 5 Alarm detection part 6 Position control part 7 Program control part 8 Memory TL Disturbance T'L Estimated disturbance torque Tr Disturbance maximum level J Motor + Load inertia Jn Motor + Load inertia Estimated value

Claims (2)

In a press working machine having a servo mechanism for moving a workpiece to a press working position, a dregs up detection mechanism for detecting an abnormal load generated when the dregs of the workpiece are on the upper surface of the die and collided with the dregs of the servo mechanism With
  The dregs up detection mechanism includes a calculation unit that calculates a target position and a disturbance maximum value, and a position control unit,
  The position control unit compares a target position with a current position and generates a target speed from an error amount, and a position loop gain;
  A filter circuit for converting the target speed into a current command;
  A first conversion circuit for converting the current command into an actual speed in consideration of a torque constant and an inertia value;
  A second conversion circuit for converting the actual speed into a current position;
  Further, a disturbance estimation unit that converts the current command and the actual speed to recognize an estimated disturbance torque;
  A comparator for recognizing disturbance torque by monitoring current and detecting when the disturbance torque exceeds the disturbance maximum torque;
  A press working machine with a dregs-up detection mechanism characterized by comprising: 2. The upsurge detection mechanism according to claim 1, wherein the upswing detection mechanism detects a torque change due to a disturbance, a speed change due to the disturbance, or a change in an error amount due to the disturbance by comparing with a normal waveform at a lift-up position. Press machine with detection mechanism.

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