JPS5987507A - Fixed position stop control device - Google Patents

Abstract

PURPOSE:To stop always a moving body at a set position by executing a fixed position control after an information of a counter comes to correspond to a position of the moving body. CONSTITUTION:A rotating body 108 for moving a tool table of a machine tool is driven by a motor 106, a position of the tool table is detected by a pulse encoder 105 directly connected to a shaft of the rotating body 108, and a pulse corresponding to a position of the tool table, which is outputted from the encoder 105 is inputted to a fixed position control device 1. In the device 1, the pulse from the encoder 105 is counted by a counter, and when this counting value becomes equal to a set value corresponding to a prescribed stop position, a stop command of the motor 106 is generated to a driving unit 107 through a switch 2, and the motor 106 is stopped. When driving the rotating body 108, the switch 2 is switched, and a driving speed command value from a numerical control device 104 is inputted to the unit 107.

Description

[Detailed description of the invention] The present invention is directed to a fixed position stop control device.

In a feeding device for a moving object such as a tool stand in a numerically controlled machine tool, the output pulses of a pulse encoder that detects the rotational speed of the drive shaft are counted by a binary up-down counter (hereinafter referred to as a counter), and the counted value of the counter is When the set value is reached, a command to stop the drive shaft is issued to stop the tool stand at a fixed position. Generally, when the device is powered on, the output of the counter is a value determined by the conditions of the element, etc., and does not correspond to the position of one moving object. When the moving object reaches a predetermined position, a load signal is input to the counter, and a set value is preset, counting of Taharunu starts corresponding to the position of the moving object. Therefore, if a stop command is issued before a load signal is input to the counter, there is a problem that the movable body will stop at the wrong position due to incorrect information on the counter.

In addition, the power supply to the control system of numerically controlled machine tools is
As shown in the figure, from the power supply 101 to the main contact) 10
A strong power panel 1 that supplies power to an electric motor (not shown) through 2.
03, the path is the numerical control device 104 and the pulse encoder 105, and the pulse encoder 105 is connected to the numerical control device 1.
Power is supplied when power is turned on in 04. However, when the power of the numerical control device 104 is turned on, the pulse encoder 10
5, a pulse due to a malfunction may be output to the output of the pulse encoder 105, and if this pulse is input to the counter as a load signal, the counter will detect when a load signal is output due to a malfunction of the tool stand. A position shifted by the difference between the position and the position where the original load signal is output is detected. Therefore, when a fixed position stop command is issued in this state, the tool stand does not stop at the original stop position, but stops at an incorrect position. Furthermore, even if the power to the pulse encoder 105 stabilizes after the power to the numerical control device 104 is turned on, unless a load signal corresponding to the initial accurate position of the tool rest is input to the counter,
The information on the counter that does not correspond to the position of the tool rest when the power to the control system is turned on ends up staying at a misaligned position.

The present invention has been made in view of the above problems, and its purpose is to perform fixed position stop control after the counter information corresponds to the position of the moving object, so that the moving object is always kept at the set position. An object of the present invention is to provide a fixed position stop control device that can stop a moving body.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

As shown in FIG. 2, the stop control command value output from the fixed position stop control device 1 is input via the switch 2 to the drive unit 107 that supplies power to the motor 106. The motor 106 drives a rotating body 108 that moves, for example, a tool stand (not shown) of a machine tool.
The position of the tool stand is detected by a pulse encoder 105 directly connected to the axis of the tool stand, and a pulse corresponding to the position of the tool stand outputted from the pulse encoder 105 is input to the fixed position stop control device. In the fixed position stop control device 1, the pulse encoder 105 or Ranoharune is counted by a counter described later, and when the counted value of this counter becomes equal to a set value corresponding to a predetermined stop position, a command to stop the motor 106 is issued to the drive unit 107. . Note that the drive unit 107 includes a rotating body 1 that is not subject to stop control.
08 is driven, the switch 2 is switched and a speed command value for driving is inputted from the numerical control device 104.

The configuration and operation of the above-described fixed position stop control device 1 will be explained below.

As shown in FIG. 3, pulses from the pulse encoder IO5, which detects the rotation speed of the rotating body 108, that is, the position of the tool stand, are sent to the pulse synthesis circuit 3 via a 3-bit signal line 4a.
Input via +4b+4c. Signal line 4a
, 4b, the rotational direction of the rotating body 108 is discriminated based on whether the phase difference between the two types of pulses on 4b is positive or negative. One pulse on the signal line 4C is output every time the rotating body 108 rotates once, and this pulse is input to the counter 5 as a load signal.

The counter 5 counts the pulses input from the pulse synthesis circuit 3 via the signal lines 6a+6b. Further, a reference value corresponding to the reference position of the tool stand is set on the counter 5 by a reference value setting device 7. The counter 5 subtracts from this set reference value every time a pulse from the pulse encoder 105 is input.

The count output of this counter 5 is converted into an analog signal by a DA converter 8. The output terminal of the D-A converter 8 is connected to one terminal 2a of a switch 2 interposed between the fixed position stop control device 1 and the drive unit 107. 9
is a stop control zone detection circuit. In this stop control zone detection circuit 9, the count output of the counter 5 is input, and when the count value of the counter 5 reaches a predetermined value, it is determined that the tool stand has reached the position where stop control is started. Outputs a signal representing .

The numerical control device 104 inputs a speed command value for driving to the drive unit 107 via the switch 2, supplies power to the PAL 7 encoder 105, and also inputs the machine tool to the first input terminal of the AND circuit 10. Gives a driving signal indicating that the vehicle is in operation.

The load signal input to the counter 5 via the signal line 6C from the three pulse synthesis circuits described above is also applied to the second input terminal of the AND circuit 10, and both of the two input terminals of the AND circuit 10 are When the output terminal becomes "High" level, the output terminal becomes "IH1gh". At this time, the flip-flop 11 is set and the output terminal 11a becomes "High".
High ' Invert to level.

The output signal of the stop control zone detection circuit 9 described above is applied to the first input terminal of the AND circuit 12.
The signal of the output terminal 11a of the flip-flop 11 described above is applied to the second input terminal of the flip-flop 2. When these two input terminals of the AND circuit 12 both go to "High" level, the output terminal of the AND circuit 12 becomes 'High'.
" level, and this signal is given to the drive circuit 2C of the switch 2. When the output terminal of the AND circuit 12 is at the 'Higb' level, the switch 2 closes to the terminal 2a side, and the output terminal of the AND circuit 12 is at the 'Higb' level. If it is at 'Low' level, it closes to the terminal 2b side.

While the machine tool is in operation, when the tool rest reaches a predetermined position near a predetermined stop position and the count value of the counter 5 matches the predetermined value, a signal is sent from the stop control zone detection circuit 9. 'High' level signal is output.Furthermore, at this time, the numerical control device 1
04 is outputting a signal indicating that it is in operation, and the pulse encoder 105 is outputting a pulse, that is, a load signal, at a rate of one per rotation of the rotating body. The flip-flop 11 is set, the output terminal of the AND circuit 12 becomes "High", and the switch 2 is switched from the terminal 2b side to the terminal 2a side.As a result, the drive unit 1
At step 07, instead of the speed command for driving the tool stand that had been input from the numerical control device 104, the speed command value for the 'stop control' from the fixed position stop control device 1 is input. In this case - a state in which a signal indicating that it is in operation is output from the numerical control device 104, that is, a state in which the power supply to the pulse encoder 105 is stable and a load signal is output from the PAL7 encoder 105. In this case, the count value of the counter 5 corresponds to the position of the tool stand, so when the switch 2 is closed to the terminal 2a side, D
Stop control is performed using a speed command value corresponding to the position of the tool stand from the -A converter 8, and the tool stand is stopped at a predetermined stop position.

When the machine tool starts operating and the numerical control device 104 is turned on, power is supplied to the pulse encoder 105. When the pulse encoder 105 outputs a pulse 7 due to a malfunction when the power is turned on, this pulse is input to the counter 5, and the counter 5 holds information on the position of the tool stand. However, at this time, a signal indicating that the operation is in progress from the numerical control device 104, or a signal indicating that the power supply of the Wachiparnu encoder 105 is stable, is input to the AND circuit 10, and the flip-flop 11 is in the reset state. 1
Since the two terminals 11a of 1 are at the "Low" level, the gate of the AND circuit 12 is closed. Therefore, at this time, the signal to start the stop control from the stop control zone detection circuit 9 due to the incorrect information in the counter 5 is blocked by the AND circuit 12, so the switch 2 is not switched, and the signal from the numerical controller 104 is blocked. The tool stand is controlled by the speed command value. That is, stop control based on incorrect position information of the tool stand is prohibited.

The counter 5 counts pulses corresponding to the position of the tool stand after a signal indicating that the pulse encoder 105 is in operation is outputted from the numerical control device 104 indicating that the power supply to the pulse encoder 105 has become stable. At this time, the numerical control device 104
When the first pulse is input from the pulse encoder 105 to the counter 5 after the operating signal is output from the counter 5, the counter 5 starts to hold information corresponding to the position of the tool stand, and the Through this, the flip-flop 11 is set, the gate of the AND circuit 12 is opened, and stop control based on the information from the counter 5 becomes possible. When the tool stand moves and the count value of the counter 5 reaches a predetermined value, the output terminal of the stop control zone detection circuit 9 becomes 'High.
'' level, the output terminal of the AND circuit 12 becomes '
I-(high") and the switch 2 is closed to the terminal 2a side. At this time, the information corresponding to the position of the tool stand held in the counter 5 is converted into an analog signal by the DA converter 8 and the switch is stopped. This is input to the drive unit 107 as a speed command value during control, and the tool stand stops when it reaches a predetermined stop position.

As explained above, in the present invention, it is detected that the power supply applied to the pulse encoder is stabilized, and the pulse encoder is outputted from the pulse encoder after the power supply is stabilized. Since the driving body is controlled to stop, the accuracy of stopping the driven body can be improved.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the power supply system of a numerically controlled machine tool, Fig. 2 is a block diagram showing a control system of a numerically controlled machine tool equipped with the fixed position stop control device of the invention, and Fig. 3 is a block diagram showing the control system of the numerically controlled machine tool equipped with the fixed position stop control device of the invention. Fixed position stop control device -1... Fixed position stop control device, 2... Nuitch, 3... Pulse synthesis circuit, 7...
- Setting device, 8... D-A converter, 9... Stop control zone detection circuit, 10.12... AND circuit = 11...
・Flip-flop, 104...Numerical control! Place, 10
5...Pulse encoder, 107...Drive unit. Patent applicant Fuji Electric Seizo Co., Ltd. Representative patent attorney Aoyama Boda 2 people

Claims (1)

[Claims] (1) A pulse encoder that outputs a pulse signal corresponding to the position of the driven object, and a first signal that counts the pulses from this pulse encoder and outputs a speed command signal to control the stop of the driven object. an output means, a detection means for detecting that the power supply applied to the pulse encoder is stabilized, a signal is output from the detection means, a pulse is output from the pulse encoder, and a count value of the first signal output means; and a second signal output means for outputting a signal that enables the signal from the first signal output means to be input to the driving device of the driven body when the pulse encoder reaches a predetermined value, and when the power source of the pulse encoder is unstable. A fixed position stop control device, characterized in that stop control based on a speed command signal from the first signal output for counting pulses from a pulse encoder is prohibited.