DESC:FIELD OF THE INVENTION
The present invention relates to condition monitoring for textile spinning machine and more specifically the invention relates to a method of monitoring the machine parameters such as mechanical behavior / vibrations / vibrational energy caused due to unbalanced system in textile spinning machines such as Blow room, card, draw frame, comber, lap former, flyers, ring frame, winding machines etc.

BACKGROUND OF THE INVENTION
The textile spinning machines are equipped to convert the fiber raw material into spun yarn through various processes. In spinning mill, plurality of machines are at continuous working state to yield high production rate. Over the long period of time, wear and tear gradually occurs in the said spinning machines. While proceeding further production, some of the difficulties occur in machine parameters due to damaged bearings, bearing vibration, worn out gears, worn out drive train, and drastic increase in motor temperature, speed, current & torque which leads to change in mechanical behavior or unbalanced system.

Aforesaid failures happens frequently in spinning machines due to continuous running conditions. This frequent failures affects the overall production efficiency because of the increased machine down time for maintenance and repair. Also some of the major accidents caused by the unexpected failure of machine part and thereby increased maintenance cost to rectify the damages. Also many technicians have to be engaged for attending / resolving the sudden failures. In conventional method, machines are periodically monitored manually to prevent these major failures / accidents.

In current practice, based on variation in machine parameter, a preventive maintenance is scheduled in advance to avoid consequential damages. Condition monitoring is the process of monitoring various physical parameters or mechanical health condition of the machinery such as vibration, worn out bearing etc. Thereby one can identify a significant change in machine performance which is the indication of mechanical fault occurrence. It is a major component of predictive maintenance. Some known predictive maintenance is performed by providing external group of sensors. The said external sensors are placed on the respective parts of the machine which are prone to getting failure. Based on the result from the sensor, the working states of the machine parts are analyzed. The abnormal results are identified and warning signal is intimated to operator or machine is stopped automatically based on the signal triggered by control system.

Drastic environment change and abnormal vibration of machine parts leads to wobble in machine fittings. Due to wobbling / vibration, external sensors deliver unreliable result since those abnormal behavior occasionally damages sensitivity of the sensors also. Hence the sensors equipped in machines for condition monitoring needs to be replaced frequently for collecting the accurate data of machine parameters. Said frequent replacement of sensor adversely affects the production efficiency, increases machine idle time, increases maintenance cost and labour / technician engagement. This inappropriate result affects the predictive maintenance of machine.

There has thus been a need to develop a life time of machine parts for high production with desirable quality that would overcome the disadvantages present in the existing machines.

OBJECTS OF THE INVENTION
Primary objective of present invention is to provide an abnormality monitoring method for monitoring machine parameter without external sensors in the textile spinning machines.

Another objective of the present invention is to effectively monitor the abnormality or unbalance condition of machine-like motor temperature, speed, current and torque etc.

Yet another objective of present invention is to minimize the frequent replacement of machine components and attain reliable output from the machines.

SUMMARY OF THE INVENTION
To meet the objectives of the present invention, the servo drives / frequency drives of the textile machines are equipped with monitoring system to identify the abnormal behavior of machine. Internal current sensing devices of the servo drive is used to capture the unbalanced machine behavior caused by damaged bearing and gears. The mechanical vibration energy is monitored by servo drive and said vibration is transferred in frequency domain of the drive train. Since the unbalanced machine behavior causes drastic increase in motor temperature, speed, current, torque and abnormal vibrations, it directly influences the motor current flow. Thus an external sensor or group of sensor for sensing the physical parameter of the machine is not required at all. The initial parameter taken on new machine is utilized as standard or reference value. This standard measurement is fixed as threshold value in servo drive. Transferring of data is carried out to controller via industrial communication protocol (CAN / POWERLINK /Ethernet IP/ Ethercat / Profinet / Profibus / RS485 / RS232 / CCLink / SERCOS / DEVICE NET / IO LINK / serial and other field communications) during abnormality occurrence. If the real-time abnormality / vibration value exceeds the threshold value, the control unit processes it within milliseconds / micro seconds and informs the behavior of machine by generating the alarm signal. Apart from detecting vibration energy, the servo drives also detect abnormality / unbalance in the machine such as sudden increase in motor temperature, speed, current & torque, change in mechanical behavior of the system etc,

BRIEF DESCRIPTION OF THE DRAWINGS

Figure-1 illustrates a spinning preparatory machine for example a draw frame.

Figure-2 shows the detailed view of abnormality monitoring system with servo drive inbuilt sensing system in a textile spinning preparatory machine according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION
Spinning mill production line comprises a plurality of machines which are assembled from preparatory machines to spinning machines to produce a fine yarn. For this, the raw fibers transformation begins in blow room, card, draw frame, lap former and comber which are called spinning preparatory machines and the final product or yarn is obtained from spinning machine such as roving frame, ring spinning, air jet or rotor spinning and winding machines etc.

For example, the present invention explains in detail about one of spinning preparatory machine draw frame (A) as shown in Figure-1. The sliver deposited in sliver barrel is fed to draw frame. Said feed slivers of draw frame are passed through guide rollers of the creel further. Normally 6 to 12 carded sliver barrels are arranged in feeding zone (1). Plurality of slivers are processed to get a single sliver strand after drafting. The primary function of a draw frame is doubling and drafting. Fed card slivers are scanned for eliminating irregularity and moved forward to drafting unit (2). Said drafting unit (2) comprises of 3 over 3 or 4 over 3 drafting rollers arrangement. After drafting, the drawn sliver gets deposited on sliver container through coiler unit (3). Finally drawn sliver can is then transported to further process.

Machine parameters such as temperature, pressure, acceleration, vibration, current, torque etc need to be monitored to avoid unwanted machine down time. As explained herein before, these parameters are detected by using sensors example, temperature sensor for detecting the temperature level of running parts in machine like motor, gear box, drafting rollers and bearings. Acceleration sensor / vibration detecting sensor monitor the vibration of motor shaft, pressure sensor for detecting the pressure level of suction. For example, a temperature sensor continuously senses the motor temperature. If the motor temperature cross beyond the threshold limit, the operator gets notification of warning signal through alarm, display (HMI) or LED. Above said group of sensors are used to monitor machine parameter which are placed at respective parts of machine.

According to an embodiment of present invention, there is provided an abnormality monitoring system in textile spinning machines comprising:
a servo motor adapted to drive a driven target;
a motor drive adapted to control operation of the servo motor; and
a control unit configured to monitor load torque acting on the servo motor, wherein
the motor driver is configured to detect magnitude of drive current applied to the servo motor and transmits said detected magnitude of drive current in the form of a frequency signal output to said control unit.

In a preferred embodiment, the motor drive includes a current sensor to detect the magnitude of drive current applied to the servo motor and transmit said detected magnitude of drive current in the form of a frequency signal output to said control unit.

According to another preferred embodiment, the control unit is configured to compare the load torque based on the frequency signal output from the current sensor with a pre-set threshold value and generates an alarm signal in case of said frequency exceeds said threshold value.

In another embodiment of present invention, load is indicated as vibrations occurred in said driven target.

According to another embodiment of present invention, the magnitude of drive current is obtained when vibrations occurred in said driven target, are transferred in frequency domain of respective drive train and the same influences the motor current flow which is detected by said current sensor.

Further embodiment of present invention discloses that the drive trains of said machine are directly or indirectly coupled to motor drives of the respective drive source.

In another embodiment, said threshold value is the frequency of the drive trains detected by the current sensor when the machine is new.

Another embodiment of present invention relates to an abnormality monitoring method in textile spinning machines comprising:
i. driving a target by a servo motor and controlling the operation of said servo motor by a motor drive;
ii. detecting magnitude of drive current applied to the servo motor and transmitting said detected magnitude of drive current in the form of a frequency signal output, by the motor drive, to a control unit;
iii. monitoring load torque acting on the servo motor by the control unit based on the frequency signal output received from the motor drive.

Yet another embodiment of present invention, the motor drive includes a current sensor to detect the magnitude of drive current applied to the servo motor and transmit said detected magnitude of drive current in the form of a frequency signal output to said control unit.

According to further embodiment of present invention, the monitoring load torque acting on the servo motor by the control unit based on the frequency signal output received from the motor drive comprises:
comparing the load torque based on the frequency signal output from the current sensor with a pre-set threshold value and generating an alarm signal in case of said frequency exceeds said threshold value.

According to further embodiment of present invention, said detecting magnitude of drive current applied to the servo motor comprises:
detecting magnitude of drive current when vibrations occurred in said driven target are transferred in frequency domain of respective drive train thereby influencing the motor current flow.

According to the present invention, said changes in parameter is monitored through inventive servo drive as shown in Figure-2. Machine parameters are recorded by internal or inbuilt current sensor of a servo drive. The mechanical load in a drive is a direct indication of the physical stress on a mechanical system or component. Due to mechanical load (7), vibration occurs in machine parts and these mechanical vibrations are captured through respective drive train (8). Said captured data is transferred to servo drive (4) in the form of frequency wave (9). All the drive trains (8) of the machine are directly or indirectly coupled to servo drives of the respective drive source.

Inverter or servo drive (4) is connected to respective servo motor (6) of the machine. At least a current sensing device/ sensor (5) is internally mounted in each servo drive (4). Said internal current sensing devices/ sensors (5) of the servo drive (4) are used to capture and store data of the mechanical vibrations (9) of machine through servo motor (6). The difference in physical parameters such as temperature, pressure, acceleration or vibration, current, torque etc data are recorded and transferred to said servo drives. Sometimes, a variation in mechanical vibration is caused by change in aforesaid parameters. Thus a mechanical vibration (9) is captured by internal sensing device/ sensor (5) present in the servo drive. The normal values of machine parameters taken on a new machine are considered as reference or standard measurement. This reference value is stored in drive and compared with collected data or real-time value of machine parameter which is taken from normal running condition of machine. These reference values are set as threshold limit value of drive.

Every captured data is compared with reference value or pre-set value for tracking the machine health. Aforesaid physical parameters in the form of a frequency (11) are sent to the machine controller (10). In addition, controller PLC (10) reads through industrial communication protocol (CAN / POWERLINK /Ethernet IP/ Ethercat / Profinet / Profibus / RS485 / RS232 / CCLink / SERCOS / DEVICE NET / IO LINK / serial and other field communications) to communicate the commands for stopping / alarming the machine while abnormality occurrence. The servo drive (4) gets the speed reference (12) from controller (10) while the machine is in operation.

According to one aspect of the present invention, the running condition of machine, data are recorded from various parts such as bearing, gear box or any other functional machine parts. Every collected data is compared with reference value and analyzed within milliseconds / microseconds. If the real time collected data or abnormalities exceeds the threshold limit, the system triggers an alarm signal and visually displayed in output device provided in the machine. The whole process is controlled though central processing unit (10) of the machine. The signal above the deviated abnormal situation may be displayed as, LED indication, display screen, alarm etc. Advantageously, the machine will be stopped by the control system in case the identified abnormality is serious malfunction or mechanical / electrical failure.

In the above description, the draw frame (A) has been described as a specific example of a textile spinning machine, but the present disclosure is not limited thereto. For example, the present disclosure is applicable to a textile spinning system including Blow room, card, comber, lap former, flyers, ring frame, winding machines etc in place of the draw frame (A).

Thus according to the inventive features of the invention, a separate sensor package is not required at each location of the machine where there is a failure prone zone. Moreover the predictive maintenance is made simpler and easier well in advance of complete breakdown of the machine and thereby down time is reduced at large. Since the predictive maintenance is carried out at planned regular intervals, fatigue to the operative is avoided.

In view of the present disclosure which describes the present invention, all changes, modifications and variations within the meaning and range of equivalency are considered within the scope and spirit of the invention. It is to be understood that the aspects and embodiment of the disclosure described above may be used in any combination with each other. Several of the aspects and embodiment may be combined together to form a further embodiment of the disclosure.
,CLAIMS:1. An abnormality monitoring system in textile spinning machines comprising:
a servo motor adapted to drive a driven target;
a motor drive adapted to control operation of the servo motor; and
a control unit configured to monitor load torque acting on the servo motor, wherein
the motor drive is configured to detect magnitude of drive current applied to the servo motor and transmit said detected magnitude of drive current in the form of a frequency signal output to said control unit.

2. The system as claimed in claim 1, wherein the motor drive includes a current sensor to detect the magnitude of drive current applied to the servo motor and transmit said detected magnitude of drive current in the form of a frequency signal output to said control unit.

3. The system as claimed in claim 2, wherein the control unit is configured to compare the load torque based on the frequency signal output from the current sensor with a pre-set threshold value and generates an alarm signal in case of said frequency exceeds said threshold value.

4. The system as claimed in any of the preceding claims, wherein said load is indicated as vibrations occurred in said driven target.

5. The system as claimed in any of the preceding claims, wherein said magnitude of drive current is detected by the current sensor when vibrations occurred in said driven target are transferred in frequency domain of respective drive train thereby influencing the motor current flow.

6. The system as claimed in claim 5, wherein said drive trains of said machine are directly or indirectly coupled to motor drives of the respective drive source.

7. The system as claimed in claim 3, wherein said threshold value is the frequency of the drive trains detected by the current sensor when the machine is new.

8. The system as claimed in claim 1, wherein said targets are bearing, gear box or any other functional machine parts.

9. The system as claimed in claim 3, wherein said alarm signal is displayed in LED indication, display screen or alarm.

10. The system as claimed in claim 1, wherein said motor drive gets speed reference from said control unit while said machine is in operation.

11. An abnormality monitoring method in textile spinning machines comprising:
i. driving a target by a servo motor and controlling the operation of said servo motor by a motor drive;
ii. detecting magnitude of drive current applied to the servo motor and transmitting said detected magnitude of drive current in the form of a frequency signal output, by the motor drive, to a control unit;
iii. monitoring load torque acting on the servo motor by the control unit based on the frequency signal output received from the motor drive.

12. The method as claimed in claim 11, wherein the motor drive includes a current sensor to detect the magnitude of drive current applied to the servo motor and transmit said detected magnitude of drive current in the form of a frequency signal output to said control unit.

13. The method as claimed in claim 11, wherein the monitoring load torque acting on the servo motor by the control unit based on the frequency signal output received from the motor drive comprises:
comparing the load torque based on the frequency signal output from the current sensor with a pre-set threshold value and generating an alarm signal in case of said frequency exceeds said threshold value.

14. The method as claimed in claim 11, wherein said load is indicated as vibrations occurred in said driven target.

15. The method as claimed in claim 11, wherein said detecting magnitude of drive current applied to the servo motor comprises:
detecting magnitude of drive current when vibrations occurred in said driven target are transferred in frequency domain of respective drive train thereby influencing the motor current flow.

16. The method as claimed in claim 11, wherein said threshold value is the frequency of the drive trains detected by the current sensor when the machine is new.