JPH0156796B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an operation control device for an automatic sewing machine or other automatic sewing machine, and particularly to an apparatus for controlling switching points of various special operations.

Prior Art Japanese Patent Publication No. 57-30414 discloses a method for determining the point at which a special operation is to be switched in an automatic punching machine or the like. Here, angle information of the sewing machine main shaft is obtained using an angle encoder (that is, an absolute rotary encoder) that supplies multiple bit patterns that constantly change according to the angular increment of the sewing machine main drive shaft, and this multiple bit angle information is and pre-programmed multiple bit patterns representing various angular positions, and when these patterns match, a signal is sent to command a corresponding special operation. However, since this method uses an angle encoder that supplies a plurality of bit patterns, there is a problem in that the number of wires between the angle encoder and the electronic control device increases. It has also been shown that multiple bits of angle information can be obtained by counting the output pulses using a rotational pulse signal generator (incremental rotary encoder), but in this case the number of wiring can be saved. However, there was a problem in that the count contents could be cleared due to a power outage or instantaneous power outage.

In addition, the conventional device described above requires both a storage device to store preprogrammed multiple bit patterns and a comparison device to detect matching of bit patterns, which increases the circuit configuration and increases costs. There was a problem.

Furthermore, in conventional devices, the speed of the main drive shaft of the sewing machine is not taken into account at all when determining the switching point of the special operation, and therefore, for example, when controlling the stop of the main drive shaft, if the speed fluctuates, the amount of slippage until the actual stop is also affected. There was a problem in that stop positioning became inaccurate due to fluctuations.

Purpose of the invention This invention has been made in view of the above points,
This simplifies the electrical connection between the detector and the control device for detecting the main shaft angle of the sewing machine, enables absolute angle detection regardless of power outages, and eliminates the need for a special comparison device. It is an object of the present invention to provide an operation control device for automatic sewing machines and other automatic sewing machines that can determine when to switch over to a special operation.

Summary of the Invention The motion control device according to the present invention uses a phase shift type detector that outputs an analog AC signal indicating an electrical phase shift corresponding to the angle of the sewing machine main shaft with respect to a reference AC signal to detect the angle of the sewing machine main shaft. By detecting This makes it possible to detect absolute angles that are unrelated to power outages. The electrical phase shift of the analog AC signal output from the detector is converted into a digital signal and used as an address input for the storage device. This storage device is
Information that commands various operations of the sewing machine is stored in advance at predetermined addresses, and operation instruction information is read out from the corresponding address according to the digital value input to the address (this corresponds to the sewing machine main shaft angle). . The operation of the sewing machine is controlled in accordance with the operation command information thus read.

According to another aspect of the invention, the digital conversion values corresponding to the electrical phase shift are sampled and temporarily stored, and this storage is used to determine the difference between the two digital conversion values whose sampling timings are different. Thereby, the rotational speed of the main shaft of the sewing machine is specified, and the digitally converted value for the electrical phase shift is increased or decreased in accordance with the specified speed, and advance angle compensation is performed in accordance with the speed. The digitally converted value thus compensated for the lead angle is used as the address input of the operation command word. As a result, the reading angle of the operation command word is advanced (advance angle) or delayed (retard angle) according to the speed, and factors (e.g. slip amount) according to the speed are taken into account at the time of operation switching. is determined. An advance angle according to such speed (the term advance angle also includes a de facto retard angle)
Compensation is suitable for stop control of the sewing machine spindle.

Embodiment Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

In FIG. 1, a phase shift type detector 1 is connected directly or indirectly to a sewing machine main shaft 2, and detects the rotation angle of the main shaft 2 in an analog manner. That is, it outputs an analog AC signal sin (ωt-θ) that indicates an electrical phase shift according to the angle θ of the main shaft 2 of the sewing machine with respect to the reference AC signal sin ωt (or cos ωt). The converter 3 digitally converts the electrical phase shift θ in the analog AC signal sin(ωt−θ) output from the detector 1, and outputs a digital value D〓 corresponding to this electrical phase θ. . The storage device 4 stores in advance information for commanding various operations of the sewing machine at predetermined addresses, and uses the output digital value D of the converter 3 as an address input and reads out the operation command information from the corresponding address. The operation command information read from the storage device 4 is decoded by the decoder 5,
The operation corresponding to the instruction word is executed according to the decoded output.

The spindle angle timing corresponding to various special operations of the sewing machine includes upper thread breakage inspection timing (spindle angle timing at which to check whether the upper thread is broken), bobbin thread breakage inspection timing (same timing as above regarding bobbin thread) ), stop position timing (angular timing indicating the stopping angle when the spindle should be stopped, for example, top dead center), lower position timing (angular timing used when the spindle should be stopped), and this lower position. (Used to control the frame to stop when it crosses the line and reaches the above-mentioned stop position), frame movement start timing (angular timing at which the frame should start moving), frame movement stop control timing (at least the angular timing that indicates that the needle frame should not move when the main shaft exceeds this angle), jump timing (stops the movement of the needle bar when freeing the needle bar from the main shaft) angular timing), zero position timing, and others, and information for commanding the above-mentioned special operation corresponding to the address position corresponding to these angular timing is stored in the storage device 4. The storage device 4 consists of read only memory (ROM), random access memory (RAM), and other storage circuits.
In the case of RAM, a programmer 6 is attached at the time of writing as shown by the broken line, and information corresponding to various arbitrary operations can be programmed at any address (angle). In that case, it is also possible to use the digital value D corresponding to the angle of the main shaft 2 set to a desired angle as a write address in the RAM (so-called teaching).

As the phase shift type detector 1, a variable magnetic resistance type as shown in FIG. 2, a synchronizer, a resolver, etc. can be used.

Detector 1 shown as an example in FIG.
The stator 7 includes a plurality of poles A to D provided at predetermined intervals (90 degrees as an example) in the circumferential direction, and each pole A to D.
The sewing machine includes a rotor (movable iron core) 8 inserted into a stator space surrounded by .
The rotor 8 has a shape that changes the reluctance of each pole A to D according to the rotation angle, and has an eccentric cylindrical shape, for example. Each pole A to D of stator 7
There are primary coils 1A to 1D and secondary coils 2A to 1D.
2D are wound respectively. Coils are wound around two radially opposed poles A and C so that they operate differentially, and a differential reluctance change occurs. The same goes for the other pair of poles B and D. Primary coil 1 of one pole pair A, C
Primary coils A and 1C are excited by a sine signal sin ωt, and primary coils 1B and 1D of the other poles B and D are excited by a cosine signal. As a result, the secondary coils 2A-2
As the composite output Y of D, the reference signal sin ωt (or
cos ωt) by an angle corresponding to the rotation angle θ of the rotor 8, so that a signal Y=sin(ωt−θ) can be obtained.

FIG. 2 also shows an example of a converter 3 corresponding to this variable magnetic resistance type detector 1. In the converter 3, a predetermined high-speed clock pulse CP is counted by a counter 9, and a sine/cosine generating circuit 10 generates a sine signal based on the output of the counter 9.
Generate sin ωt and cosine signal cos ωt, respectively, and send them to the primary coils 1A, 1C, 1B, 1D as described above.
are applied respectively. The output signal Y=sin(ωt−θ) of the secondary coils 2A to 2D is given to the zerox detection circuit 11, and a pulse L is outputted in synchronization with the timing of the electrical phase angle of this signal Y being zero. The output pulse L of this circuit 11 is used as a latch pulse of the latch circuit 12. Latch circuit 12 is circuit 1
The count output of the counter 9 is latched in response to the rising edge of the pulse L given from 1 to 1. counter 9
It is possible to synchronize the period during which the count value of is made one cycle with one cycle of the sine signal sin ωt, and then,
The latch circuit 12 has an electrical phase difference θ between the reference AC signal sin ωt and the sensor output signal Y=sin(ωt−θ).
The count value corresponding to is latched, and this is output as the digital conversion value D〓.

FIG. 3 shows an example in which advance angle compensation is performed in accordance with the speed of the main shaft 2 of the sewing machine. The digital value D〓 outputted from the converter 3 changes from moment to moment as the angle of the main shaft 2 of the sewing machine changes.
The speed can be specified according to the amount of change over time. For speed detection, shift register 13
and a computing unit 14 are provided. N that can store all bits of one digital value D〓 per stage
The output digital value D of the converter 3 is given to the first stage of the shift register 13 of the stage. The shift register 13 is shift-controlled by the sampling pulse S. When the sampling pulse S is generated, the current conversion value D〓 from the converter 3 is sampled in the first stage of the shift register 13, and at the same time, the data in each stage is shifted to the next stage. thus,
The digital value D〓 obtained by the converter 3 is sampled one after another as time passes, and the sampled values are successively stored in the shift register 13.

The output D〓 of the converter 3 is given to the B input of the arithmetic unit 14, and the output D〓 of the Nth stage of the shift register 13 _is
is applied to the A input of the arithmetic unit 14. Arithmetic unit 14
performs the subtraction A-B, that is, D〓 _N - D〓 (on the contrary, it can be B-A), and the converted value D〓 of the current sampling timing and the converted value D sampled N times before are calculated. 〓 Find the difference from _N. Note that the data applied to the B input of the arithmetic unit 14 may be an output signal of any stage of the shift register 13, as long as the sampling timings of the data applied to the A input and B input are shifted by a predetermined number of times.

The difference △D〓 of the digital conversion values outputted from the arithmetic unit 14 in this way is determined by the N of the sampling pulse S.
It represents the amount of angular displacement of the main shaft 2 of the sewing machine per unit time corresponding to the period, and corresponds to the speed.

For lead angle compensation, lead angle compensation data memory 15
and an addition/subtraction calculator 16 are provided, and the above-mentioned speed information △D〓 is inputted into the advance angle compensation data memory 15 as an address. The lead angle compensation data memory 15 stores in advance a function of lead angle compensation data (this value may have a plus/minus sign) in which speed is a variable. This function characteristic is set, for example, according to the speed versus inertia (slip amount from the start of stop control to the actual stop) characteristic of the main shaft of the sewing machine.

From memory 15, speed information △D〓
The advance angle compensation data d is read out with a plus/minus sign in accordance with . The arithmetic unit 16 adds or subtracts the current digital conversion value D〓 outputted from the converter 3 and the compensation data d read out from the memory 15. As a result, the apparent angle information is advanced or delayed from the current value by a compensation amount depending on the speed.
D〓+d is output from the arithmetic unit 16.

Operation command information corresponding to special operations (for example, operations related to stopping control of the main shaft of the sewing machine) for which it is preferable to perform advance angle compensation according to the speed is stored in the first storage device 4A, and the operation command information corresponding to operations that do not require such operations is stored. The information is stored in the second storage device 4B. 1st
The arithmetic unit 16 is used as an address signal for the storage device 4A.
Lead angle compensated digital value D〓 output from
+d is used, and the digital value D〓 from the converter 3 is directly used as the address signal for the second storage device 4B, as in FIG. Each storage device 4A,
The instruction word read from 4B is sent to decoders 5A, 5
They are each decoded by B. As the sampling pulse S, a predetermined clock or a latch pulse L of the latch circuit 12 (FIG. 2) in the converter 3 can be used.

With the configuration shown in FIG. 3, the read address of the storage device 4A is advanced by the amount of compensation data d corresponding to the speed of the sewing machine spindle 2 than the address corresponding to the actual digital value D (actual angle of the sewing machine spindle 2). As a result, the special operation command is output at an earlier angular timing depending on the speed. Therefore, for example, the higher the speed, the earlier the stop position timing is set, and the earlier the stop control is performed taking into account the amount of slip according to the speed. The sewing machine main shaft 2 can now be stopped at the stop position.

By the way, if the digital value D〓 outputted from the converter 3 is used as the angle information of the spindle 2, the frame (not shown) can always be kept in a constant preferred spindle angle range regardless of its X-Y movement amount. It can be moved. To do this, for example, as shown in Fig. 4, a certain angular range (for example,
0° to 240°), and read out this function by using the output digital value D of the converter 3 (that is, the angle information of the main shaft 2 of the sewing machine) as an address input. Multiply the read function value by X and Y movement amount setting coefficients in multipliers 18 and 19, respectively,
The output is used as the X- and Y-axis drive speed commands for the frame. With this configuration, the frame is necessarily moved throughout the predetermined angle range,
As a result, if the amount of movement is large, the frame will be moved relatively quickly, and if the amount of movement is small, the frame will be moved relatively slowly. conventionally,
Regardless of the size of the movement setting value, the slide frame was moved at a high speed commensurate with the maximum travel distance, which increased mechanical stress on the slide frame, causing it to wobble. In this regard, according to the application of the present invention as described above, the mechanical stress of the frame can be reduced, and rattling can be suppressed.

Effects of the Invention According to this invention, the electrical connection from the detector provided on the main shaft side of the sewing machine to the electrical/electronic control device is
Since it is provided by the main analog AC signal output line, it contributes to simplifying the wiring. Furthermore, since the electrical phase shift in the analog AC signal output from the detector is substantially absolute information, the sewing machine main shaft angle can be detected absolutely. Furthermore, since no special comparing device is required, the electric circuit configuration can be simplified. Furthermore, by introducing advance angle compensation according to speed, accurate spindle stop control becomes possible. Furthermore, by introducing the concept of using a digital value corresponding to the main axis angle as address information into the movement control of the frame, it becomes possible to perform suitable frame movement control that suppresses frame wobbling.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a schematic front view of the detector and an electrical block diagram of the converter showing an example of the detector and converter used in FIG. 1, and FIG. FIG. 4 is a block diagram showing another embodiment of the invention. FIG. 4 is a block diagram showing still another embodiment of the invention. DESCRIPTION OF SYMBOLS 1... Phase shift type detector, 2... Sewing machine main shaft, 3... Converter, 4, 4A, 4B... Storage device, 5, 5A, 5B... Decoder, 6... Programmer, 7... Stator, 8...Rotor, 13...
Shift register, 14, 16... Arithmetic unit, 15...
...Advance angle compensation data memory.

Claims (1)

[Scope of Claims] 1. A phase shift type detector which is provided in association with a sewing machine main shaft and outputs an analog AC signal indicating an electrical phase shift according to an angle of the sewing machine main shaft with respect to a reference AC signal; A converter for digitally converting the electrical phase shift in the analog AC signal output from the detector and information for commanding various operations of the sewing machine are stored in predetermined addresses respectively, and the output digital value of the converter is stored in advance. An automatic sewing machine, etc., characterized in that it comprises a storage device that reads out the operation command information from an address corresponding thereto as an address input, and the operation of the sewing machine is controlled according to the read operation command information. Operation control device for automatic sewing machines. 2. A phase shift type detector provided in connection with the sewing machine main shaft and outputting an analog AC signal indicating an electrical phase shift according to the angle of the sewing machine main shaft with respect to a reference AC signal, and A converter that digitally converts the electrical phase shift in the analog AC signal, a temporary storage circuit that samples and temporarily stores the output digital value of this converter, and a sampling timing using the stored contents of this temporary storage circuit. an arithmetic circuit that determines the rotational speed of the sewing machine main shaft by determining the difference between the two output digital values separated by a lead angle compensation unit that increases or decreases the output digital value of the converter in accordance with the specified speed; and a storage device that stores in advance information for commanding various operations of the sewing machine at predetermined addresses, and reads out the operation command information from the address corresponding to the output digital value of the advance angle compensating means as an address input. An operation control device for an automatic sewing machine or other automatic sewing machine, characterized in that the operation of the sewing machine is controlled according to read operation command information.