Monitoring device for monitoring a woven fabric using deformation sensors

Abstract

The invention relates to a system comprising: a harness for a weaving loom, and a monitoring device for monitoring the manufacturing of a preform woven by the loom, the monitoring device comprising: a plurality of sensors, each sensor of the plurality of sensors being connected to one harness cord of a plurality of harness cords and configured to measure a deformation of the harness cord, the deformation being caused by a force exerted by the loom to the harness cord to which the sensor is connected; and a processing unit connected to the plurality of sensors and configured to analyze the deformations to identify a manufacturing anomaly on at least one harness cord.

Description

Technical Field

[0001] This invention relates to the control of the manufacture of woven preforms on a loom, and more particularly to a data monitoring device for a loom for weaving management purposes. Background Technology

[0002] Jacquard looms can be used to manufacture three-dimensional (3D) preforms by weaving multiple layers between multiple warp and weft yarns. Jacquard looms can also be equipped with digital control, particularly capable of automatically weaving preforms with variations in thickness, width, and unbundling areas. These fiber preforms can then be infused with thermosetting resins to manufacture components, including turbojet engine parts such as fan blades, retaining housings, and / or straighteners.

[0003] Ensuring high-quality weaving is crucial. Furthermore, the ability to quickly and even proactively identify manufacturing defects using automated algorithms enables significant improvements in production costs.

[0004] Various automated control systems have been developed in this regard.

[0005] The first family of control systems, known as "online" control systems, is based on algorithms that process data called "thermal" data, which is acquired during the manufacturing of the preform. The first family of control systems operates in parallel with the loom and enables preventative stopping of weaving in case of problems or malfunctions during processing.

[0006] The second family of control systems, known as “offline” control systems, is based on algorithms that process data referred to as “cold” data, which is extracted from the loom after weaving is complete. This type of approach enables, for example, the prevention of non-compliant subsequent changes to preforms or even components after resin injection, or supports and accelerates controls performed by the operator during the subsequent manufacturing and control of preforms and / or components, for example, by sending instructions and their location or properties back to a tracking table.

[0007] Some control systems enable offline control through a function known as "tracking." Such a control system detects a single motor torque intensity value for each loom motor and for each weft insertion. However, this value only represents the maximum torque deployed by the specified motor during the weft insertion, and it has a discrete scale. This function has several drawbacks: it relies on the technology of the motor it is coupled to, it provides only a single value for each insertion cycle, and it has poor discretization.

[0008] In any case, data associated with the operation of the loom plays a crucial role in identifying anomalies within components manufactured using the loom. However, algorithms developed for this purpose are not always able to detect anomalies, especially when they cannot obtain accurate measurement data. This increases the need to equip the loom with a sensor system capable of providing measurement data related to potential faults. Summary of the Invention

[0009] One object of the present invention is to improve the monitoring of woven preforms manufactured by looms.

[0010] To this end, the present invention proposes a system comprising: a heald frame for a loom, the loom including a plurality of heddles, the heald frame including a collector, a binding plate, and a plurality of heddle cords guided by the binding plate and the collector, each of the plurality of heddle cords being designed to be connected to one of the plurality of heddles of the loom; and a monitoring device for monitoring the manufacturing of woven preforms by the loom, the monitoring device comprising: a plurality of sensors, each of the plurality of sensors being connected to one of the plurality of heddle cords and configured to measure deformation of the heddle cord caused by a force applied by the loom to the heddle cord to which the sensor is connected; and a processing unit connected to the plurality of sensors and configured to analyze the deformation to identify manufacturing anomalies on at least one heddle cord.

[0011] Advantageously, the invention is accomplished by employing the following features individually or in any technically feasible combination.

[0012] The processing unit is configured to analyze deformation in real time, continuously, or through controlled sampling.

[0013] The processing unit is configured to analyze deformation throughout the manufacturing process of the woven preform.

[0014] Each of the multiple sensors includes a strain gauge, preferably a piezoelectric sensor.

[0015] Each of the multiple sensors includes two ends, each of the two ends being secured to the heald rope by an adhesive element, such that the sensor extends along the heald rope. Preferably, the adhesive element comprises resin.

[0016] Each of the multiple sensors is fixed to the heald rope to form a joint between two sections of the heald rope.

[0017] Each of the multiple sensors is located on the heddle rope to extend between the binding plate and the collector.

[0018] Each of the multiple sensors includes at least a portion of a heddle rope, the at least portion of which is configured to measure the deformation of the heddle rope caused by a force applied to it by the loom; the processing unit is configured to send a command to the loom derived from the analysis of the deformation.

[0019] Therefore, this invention enables continuous measurement and processing of multiple values ​​in each insertion cycle. Furthermore, its signal discretization scale can be selected as needed, as it depends only on the acquisition unit, which is independent of the loom.

[0020] Furthermore, the analysis system is compatible with different types of electronic or mechanical heald frames and can be applied to every type of loom.

[0021] The system according to the invention also enables the acquisition of information about weaving in real time.

[0022] The ability to attach a sensor to each heald cord of the loom heald frame enables accurate and optimal identification of the type of problem and its impact on the manufactured preform. Attached Figure Description

[0023] Other features, objects, and advantages of the invention will become apparent from the following description, which is merely exemplary and non-limiting, and should be read with reference to the accompanying drawings, in which:

[0024] - Figure 1 A schematic diagram of a jacquard loom is shown;

[0025] - Figure 2 A schematic diagram of a frame according to one embodiment is shown;

[0026] - Figure 3A and Figure 3B Different states of a sensor on a heddle are shown according to one embodiment;

[0027] - Figure 4 The heald rope of a heald frame according to one embodiment is shown;

[0028] - Figure 5 The steps of a monitoring method according to one embodiment are shown;

[0029] In all the figures, similar elements have the same reference numerals. Detailed Implementation

[0030] Figure 1 A jacquard loom 1 is schematically shown for manufacturing three-dimensional (3D) preforms obtained by multi-layer weaving between multiple warp and weft layers.

[0031] The loom 1 is equipped with a jacquard mechanism comprising a plurality of control hooks. The control hooks of the jacquard mechanism are actuated in a translational manner during weaving. The jacquard mechanism is supported by an upper structure 11 referred to as the jacquard head. The loom 1 also includes a heald frame 2 and a plurality of healds 24. The heald frame 2 includes a plurality of heald cords 23. Each heald cord 23 has at least two ends, each heald cord 23 being connected to one of the control hooks of the jacquard mechanism via one of its two ends and to at least one heald cord among the healds 24 via its other end. The heald frame 2 also includes a binding plate 22 and a collector 21, the binding plate and collector being adapted to guide the heald cords 23 of the heald frame 2. The loom 1 also includes a monitoring device 3 comprising at least one sensor 30, a processing unit 31, and at least one connecting line 32 for connecting one or more sensors 30 to the processing unit 31. According to one embodiment presented below, the monitoring device 3 includes a plurality of sensors 30, such that each sensor 30 is connected to each heald rope 23, and advantageously, each heald rope 23 is connected to exactly one sensor 30.

[0032] Each heddle 24 includes an eyelet 25 through which warp yarns 40 pass. The heddle 24 and the associated eyelets 25 are driven by a substantially vertical oscillating motion. The displacement of each heddle 24 depends on several forces: the return force of the spring 26, the return force of the actuator of the jacquard head 11, the return force of the warp yarns 40, and any frictional forces generated due to the interaction at the eyelets 25. The heddle 24 can lift some of the warp yarns 40, thereby forming a shed through which the weft yarns 41 can be introduced. More specifically, each heddle 24 is individually actuated and driven, which allows each warp yarn 40 to be raised or lowered independently. Thus, the spacing of the warp yarns 40 (which is required for the rapier carrying the weft yarns 41 to pass through) can be achieved, and complex patterns can be woven, and the warp yarns 40 can be transferred from one layer to another, thereby enabling the creation of three-dimensional fiber structures. After each pass of the weft yarns 41, the beater comb 50 compacts the fabric leaving the loom 1, which makes it possible to obtain the desired weave.

[0033] The heddles 24 are spatially distributed according to the positions of the holes 221 in the binding plate 22, that is, distributed in multiple columns and rows. The density of the holes 221 in the binding plate 22 corresponds to the density of the fabric to be manufactured, that is, there is a spacing between each column of holes in the binding plate 22, which is equal to the spacing between each column of warp yarns in the fabric to be manufactured. The loom 1 also includes a warp frame for supporting multiple warp bobbins. Each bobbin can rotate about an axis so that its warp yarns can unwind. Each warp yarn can pass through the guide eye 25, then through the holes in the binding plate similar to the binding plate 22, and finally through the eyelets 25 of the heddles 24.

[0034] Figure 2A schematic diagram of a heald frame 2 of a loom 1 according to one embodiment is shown. As previously explained, the heald frame 2 includes a plurality of heald cords 23. Each heald cord 23 of the heald frame 2 is attached to a control hook of the jacquard mechanism via a first end of the heald cord. Thus, these heald cords 23 are independently subjected to a force applied by the control hook to which the heald cord is attached. Each heald cord 23 is attached to a heald wire 24 via a second end of the heald cord. Between the first end and the second end, each heald cord 23 is guided by a collector 21 and a binding plate 22. The collector 21 of the heald frame 2 is located on the first end side near the jacquard mechanism, while the binding plate 22 is located on the second end side, and thus near the heald wire 24. Thus, each heald cord 23 extends from the jacquard mechanism, through the collector 21, and then through a hole 221 in the binding plate 22 to the heald wire 24.

[0035] This heald frame can be connected to a monitoring device 3, which is used to analyze the deformation experienced by the heald rope 23. The monitoring device 3 includes a plurality of sensors 30, a processing unit 31, and a plurality of connecting lines 32. Preferably, each sensor 30 is connected to the processing unit 31 via a connecting line 32. Advantageously, each connecting line 32 includes an input cable and an output cable, each of the input cable and the output cable connecting one end of the sensor 30 to the processing unit 31.

[0036] According to a preferred embodiment, each sensor 30 is connected to each heald 23. Advantageously, each heald 23 is connected to exactly one sensor 30. Therefore, the monitoring device 3 is able to monitor the evolution of the tension in the heald 23 and thus notice changes identified as weaving defects or anomalies. Errors can occur during the weaving process. For example, a heald 23 may get stuck, come into contact with another heald, or break. It can also happen that one of the healds 23 is not in a good position, resulting in over-tension or under-tension. Such interference is detrimental to the quality of the woven preform.

[0037] The processing unit 31 analyzes the deformation related to the force applied to the heddle 23, based on data measured by the sensor 30 located on the heddle 23 and transmitted to the processing unit via the connecting line 32.

[0038] The monitoring device 3 is independent of the loom 1, and therefore can be applied to each loom 1. The monitoring device can detect any tension anomalies on each heald 23, including the sensor 30. Furthermore, the discretization scale of the analysis signal depends only on the monitoring device 3, and can therefore be selected independently of the loom 1. Thus, sampling is modifiable and can be controlled independently of the loom 1.

[0039] Each sensor 30 is located on each heald rope 23 of the heald frame 2, and advantageously positioned between the collector 21 and the binding plate 22 to avoid friction problems between the sensors 30. The spacing between the heald ropes 23 is relatively large at this level, and to ensure that the connecting wire 32 is confined in this area. The position of the sensor 30 between the binding plate 22 and the collector 21 prevents the connecting wire 32 from the sensor 30 to the processing unit 31 from interfering with the weaving. It facilitates the installation of the sensor 30 and prevents the heald rope 23 from getting stuck due to the presence of the sensor 30.

[0040] Therefore, the working environment will not be affected by the presence of sensor 30 and the corresponding connecting line 32.

[0041] According to one embodiment, the sensor 30 is positioned such that it does not come into contact with the collector 21 and / or the binding plate 22 during the displacement of the heddle 23 between a high position and a low position. The high position is obtained under the action of the traction force applied by the hook attached to the heddle 23, and the low position is obtained once released under the action of the return force of the spring 26. One operating mode of the sensor 30 is described in detail below.

[0042] The sensors 30 are preferably strain gauges, advantageously piezoelectric, but they can be any other type. The end of each sensor 30 is fixed to one of the heddles 23 to elongate according to the deformation of the heddles 23 while allowing the heddles 23 to deform freely. Advantageously, the sensors 30 are fixed to the heddles 23 by means of resin or other adhesive materials.

[0043] According to one embodiment, the end of each sensor 30 is fixed to the heald rope 23 along a portion of the heald rope 23. This configuration may be referred to as "parallel fixing," and according to another embodiment, the end of each sensor 30 is fixed to the heald rope 23 to form a joint between two sections of the heald rope 23; this other configuration may be referred to as "serial fixing."

[0044] Figure 3A and Figure 3B The state of sensor 30 during the application of a force F to helium rope 23 to which the sensor is fixed is shown. As described above, the end of sensor 30 is connected to helium rope 23, and during the application of force F to helium rope 23, sensor 30 experiences the same displacement as helium rope 23. Sensor 30 then measures the force F applied to helium rope 23 by measuring the deformation caused by the displacement of helium rope 23. In fact, the deformation is a function of the tension applied to helium rope 23 by force F. If no force is applied to helium rope 23 ( Figure 3A If no deformation is detected by sensor 30, the relative force measured will be zero; however, if a force F is applied... Figure 3B If the sensor 30 measures the deformation of the heddle rope 23 and the output force F, then the sensor 30 measures the deformation of the heddle rope 23 and the output force F.

[0045] According to one embodiment, such as Figure 4 As shown, each sensor 30 includes at least a portion of each heddle cord 23. This heddle cord portion 23 is configured to measure the deformation of the heddle cord 23 caused by the force F applied to it by the loom 1. Preferably, the sensor 30 includes the entire length of the heddle cord 23, in which case the heddle cord 23 is considered piezoresistive. In addition to its function of transmitting force from the jacquard loom to the heddle yarns 24, the heddle cord 23 also has a measurement function. In this embodiment, the heddle cord 23 assumes the role and function of the sensor 30. This implementation allows for limiting the size of the loom 1 and improving the integration of the monitoring device 3 within the loom 1. Furthermore, it improves the accuracy of the measurement.

[0046] Figure 5 The general steps of a method for monitoring the manufacturing of a woven preform by a loom according to one embodiment are shown. Monitoring of the manufacturing of the woven preform is performed on a loom 1. Preferably, loom 1 is the loom described previously and is manufactured by… Figure 1 As shown, however, the loom can be any other loom. The loom 1 used includes those described above and is made of... Figure 2 The heald frame 2 is shown. The heald frame 2 includes multiple heald cords 23 for connecting the jacquard mechanism to heald wires 24, which are used to lift the warp yarns 40. The heald cords 30 transmit the movement of the hooks of the jacquard mechanism to the warp yarns 40, thereby enabling weaving.

[0047] This loom 1 includes at least one sensor 30 on each of its heald cords 23, which are then driven by a jacquard mechanism. According to the weaving program, each hook is controlled to apply a force F to the heald cord 23 to which the hook is attached. During the step of applying force F to one (or more) heald cords 23, the internal tension of the heald cord 23 increases, and force F is transmitted to the heald wires 24 connected to the heald cord 23. The sensor 30, attached to the heald cord 23 (to which force is applied), then measures the force E1 applied to the heald cord 23 by measuring the deformation caused by the displacement of the heald cord 23. As previously described, the end of each sensor 30 is attached to one of the heald cords 23, and the change in tension of the heald cord 23 due to the applied force is measured by the sensor 30. The jacquard mechanism can simultaneously actuate multiple control hooks, then multiple heald cords 23 are subjected to force F, and then the sensor 30, fixed to these heald cords 23, measures the force E1 applied to the multiple heald cords 23.

[0048] The measurement results are then transmitted via a connection line 32 that connects each sensor 30 to the processing unit 31. The processing unit 31 analyzes the data received by the multiple sensors 30 on E2 to identify manufacturing anomalies on at least one or more heddles in the heddles 23.

[0049] According to one embodiment, the processing unit 31 is adapted to send an E3 command to the loom 1, which is derived from an analysis E2 of the deformation of each heald 23 connected to the sensor 30. This enables improvements to the weaving method and may prevent further degradation of the loom and / or the weaving preform.

Claims

1. A system comprising: - A heald frame (2) for a loom (1), the heald frame comprising: - Multiple heddles (24), each heddles including eyelets (25), and warp yarns (40) configured to pass through the eyelets. - Collector (21), and - Strapping plate (22). - A plurality of heddles (23) guided by the binding plate (22) and the collector (21), each of the plurality of heddles (23) being designed to be connected via a first end to a control hook of the jacquard mechanism and via a second end to one of the heddles (24); and - A monitoring device (3) for monitoring the manufacturing of woven preforms by the loom (1), the monitoring device (3) comprising: - A plurality of sensors (30), each of the plurality of sensors (30) being connected to one of the plurality of heddles (23) and configured to measure the deformation of the heddle (23) caused by a force applied by the loom (1) to the heddle (23) to which the sensor (30) is connected; and - A processing unit (31) is connected to the plurality of sensors (30) and configured to analyze the deformation to identify manufacturing anomalies on at least one heddle (23).

2. The system according to claim 1, wherein, The processing unit (31) is configured to analyze the deformation in real time, continuously, or through controlled sampling.

3. The system according to claim 1 or 2, wherein, The processing unit (31) is configured to analyze the deformation throughout the manufacturing process of the woven preform.

4. The system according to claim 1 or 2, wherein, Each of the plurality of sensors (30) includes a strain gauge.

5. The system according to claim 1 or 2, wherein, Each of the plurality of sensors (30) includes two ends, each of the two ends being secured to the heddle rope (23) by an adhesive element, such that the sensor (30) extends along the heddle rope (23).

6. The system according to claim 1 or 2, wherein, Each of the plurality of sensors (30) is fixed to the heddle (23) to form a joint between two sections of the heddle (23).

7. The system according to claim 1 or 2, wherein, Each of the plurality of sensors (30) is located on the heddle rope (23) to extend between the binding plate (22) and the collector (21).

8. The system according to claim 1 or 2, wherein, Each of the plurality of sensors (30) includes at least a portion of the heddle (23), the at least portion of which is configured to measure the deformation of the heddle (23) caused by the force applied to the heddle (23) by the loom (1).

9. The system according to claim 1 or 2, wherein, The processing unit (31) is configured to send instructions to the loom (1) based on an analysis of the deformation.

10. The system according to claim 4, wherein, The sensor (30) is a piezoelectric sensor.

11. The system according to claim 5, wherein, The adhesive element comprises resin.

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