Monitoring device for monitoring knitting by using deformation sensor

Abstract

The present invention relates to a system comprising: a heald frame for a weaving loom, and a monitoring device for monitoring the manufacture 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 of a plurality of heald cords and configured to measure a deformation of the heald cords, the deformation is caused by the force applied to the heald rope connected with the sensor by the weaving machine; and a processing unit connected to the plurality of sensors and configured to analyze the deformations to identify manufacturing anomalies on the at least one heald rope.

Description

Technical Field

[0001] The present invention relates to the control of a weaving machine for manufacturing a woven preform, and more particularly to a data monitoring device of the weaving machine for the purpose of weaving management. Background Art

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

[0003] Ensuring that the braiding quality is good is important, and the ability to quickly and even preemptively identify manufacturing defects using automated algorithms enables significant improvements in production costs.

[0004] In this regard, various automated control systems have been developed.

[0005] A first family of control systems, known as “online” control systems, is based on algorithms that process data known as “hot” data, already acquired during the manufacture of the preform. This first family of control systems works in parallel with the loom and enables preventive stopping of weaving in the event of a problem during the process or in the event of a malfunction.

[0006] A second family of control systems, known as “offline” control systems, is based on algorithms that process so-called “cold” data, which are extracted from the loom after weaving is complete. This type of approach makes it possible, for example, to avoid subsequent undesirable changes to the preform or even the component after the resin injection, or to support and accelerate the control performed by the operator during the subsequent manufacture and control of the preform and / or component, for example by sending indications and their positions or their properties back to a tracking table.

[0007] Some control systems enable off-line control through a function known as a "tracking" function. Such control systems detect a single motor torque intensity value for each loom motor and for each weft insertion. However, this value only represents the maximum torque value deployed by a given motor during a weft insertion, and this has a discrete scale. However, this function has several disadvantages: it depends on the technology of the motor to which it is coupled, it only provides a single value per insertion cycle, and it has a poor discretization.

[0008] In any case, data associated with the operation of a loom plays a key role in identifying anomalies within the components manufactured using the loom. However, the algorithms developed for this purpose are not always able to detect anomalies, especially when the algorithms are unable to obtain the correct measurement data, which increases the need to equip looms with sensor systems that can provide measurement data related to potential faults. Summary of the invention

[0009] An object of the present invention is to improve the monitoring of a weaving machine producing woven preforms.

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

[0011] Advantageously, the invention is achieved by means of the features described below, taken alone or in any technically feasible combination.

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

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

[0014] Each sensor of the plurality of sensors comprises a strain gauge, and preferably the sensors are piezoelectric type sensors.

[0015] Each sensor of the plurality of sensors comprises two ends, each of the two ends being fixed to the heald rope by an adhesive element such that the sensor extends along the heald rope, preferably the adhesive element comprises a resin.

[0016] Each sensor of the plurality of sensors is secured to a heald rope to form a junction between two sections of the heald rope.

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

[0018] Each sensor of the plurality of sensors comprises at least a portion of a heddle configured to measure a deformation of the heddle caused by a force applied to the heddle by the loom; the processing unit is configured to send instructions to the loom, the instructions being derived from the analysis of the deformation.

[0019] The invention thus enables continuous measurement and processing of multiple values ​​in each insertion cycle. Furthermore, its signal discretization scale can be selected as desired, since 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 heald frames or mechanical heald frames and can be adapted to each weaving machine.

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

[0022] The ability to fix a sensor on each heald of a weaving machine heald frame allows accurate and optimal identification of the type of problem and its impact on the preform being manufactured. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Other features, objects and advantages of the present invention will appear from the following description, which is purely 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-type loom is shown;

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

[0026] - Figure 3A and Figure 3B shows different states of a sensor on a heddle rope according to one embodiment;

[0027] - Figure 4 A 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 DESCRIPTION

[0030] Figure 1 A Jacquard-type weaving machine 1 is schematically shown for manufacturing a three-dimensional (3D) preform obtained by multi-layer weaving between a plurality of warp yarn layers and a plurality of weft yarn layers.

[0031] The loom 1 is equipped with a jacquard mechanism, which includes 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, which is called a 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 ropes 23. Each of the plurality of heald ropes 23 has at least two ends, each heald rope 23 is connected to one of the control hooks of the jacquard mechanism by one of the two ends, and is connected to at least one of the heald ropes 24 by the other end. The heald frame 2 also includes a tying plate 22 and a collector 21, which are suitable for guiding the heald ropes 23 of the heald frame 2. The loom 1 also includes a monitoring device 3, which includes 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 comprises a plurality of sensors 30 , such that each sensor 30 is connected to each heald 23 , and advantageously, each heald 23 has exactly one sensor 30 connected to it.

[0032] Each heald 24 comprises an eyelet 25 through which a warp yarn 40 passes. The heald 24 and the eyelet 25 associated with the heald are driven by a substantially vertical oscillating motion. The displacement of each heald 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 yarn 40 and any friction generated by the interaction at the eyelet 25. The heald 24 is able to lift some of the warp yarns 40, thereby forming a shed into which a weft yarn 41 can be introduced. More specifically, each heald 24 is individually actuated and driven, which can independently raise or lower each warp yarn 40. Thus, the spacing of the warp yarns 40 (which is required to pass the rapier carrying the weft yarns 41) 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 a three-dimensional fiber structure. After each passage of the weft yarn 41, the beating comb 50 compacts the fabric leaving the loom 1, which enables the desired weaving to be obtained.

[0033] The healds 24 are spatially distributed according to the positions of the holes 221 of the binding plate 22, that is, according to 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, which is used to support a plurality of warp yarn bobbins. Each bobbin can rotate around an axis so that its warp yarn can be unwound. Each warp yarn can pass through a guide eye 25, then through a hole in a binding plate similar to the binding plate 22, and finally through the eye 25 of the heald 24.

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

[0035] Such a heald frame can be coupled to a monitoring device 3 for analyzing the deformations to which the heald ropes 23 are subjected. The monitoring device 3 comprises: a plurality of sensors 30, a processing unit 31 and a plurality of connection lines 32. Preferably, each sensor 30 is connected to the processing unit 31 via a connection line 32. Advantageously, each connection line 32 comprises an input cable and an output cable, each of which connects 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, exactly one sensor 30 is connected to each heald 23. Thus, the monitoring device 3 is able to monitor the evolution of the tension of the healds 23 and thus to note changes that are identified as weaving defects or anomalies. Errors may occur during the weaving process. For example, a heald 23 may get stuck, come into contact with another heald, or break. It may also happen that one of the healds 23 is not in a good position, which may produce over-tension or under-tension. Such disturbances are detrimental to the quality of the woven preform.

[0037] The processing unit 31 analyses the deformations associated with the application of forces to the healds 23 thanks to the data measured by the sensors 30 located on the healds 23 and transmitted to the processing unit via the connecting line 32 .

[0038] The monitoring device 3 is independent of the loom 1 and can therefore be adapted to each loom 1. The monitoring device is able to detect any tension anomaly on each heald 23 comprising 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. The sampling is thus modifiable and can be controlled independently of the loom 1.

[0039] Each sensor 30 is located on each heald 23 of the heald frame 2 and is advantageously located between the collector 21 and the lashing plate 22 to avoid friction problems between the sensors 30, the spacing between the healds 23 being greater at this level, and to ensure that the connecting wires 32 are confined to this area. The location of the sensors 30 between the lashing plate 22 and the collector 21 prevents the connecting wires 32 connecting from the sensors 30 to the processing unit 31 from interfering with the weaving. It facilitates the installation of the sensors 30 and prevents the healds 23 from getting stuck due to the presence of the sensors 30.

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

[0041] According to one embodiment, the sensor 30 is positioned so as not to come into contact with the collector 21 and / or the lashing plate 22 during the displacement of the heald 23 between the high position and the low position. The high position is obtained under the effect of the traction force exerted by the hook coupled to the heald 23, and the low position is obtained once released under the effect of the return force of the spring 26. One mode of operation of the sensor 30 is explained in detail below.

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

[0043] According to one embodiment, the ends of each sensor 30 are fixed to the heald 23 to follow a portion of the heald 23. This configuration can be called "parallel fixing", and according to another embodiment, the ends of each sensor 30 are fixed to the heald 23 to form a junction between two sections of the heald 23; this other configuration can be called "serial fixing".

[0044] Figure 3A and Figure 3B 1 shows the state of the sensor 30 during the application of a force F to the heald 23 to which the sensor is fixed. As explained above, the ends of the sensor 30 are coupled to the heald 23, and during the application of the force F to this heald 30, the sensor 30 undergoes the same displacement as the heald 23. The sensor 30 then measures the force F applied to the heald 23 by measuring the deformation caused by the displacement of the heald 23. In fact, the deformation is a function of the tension applied to the heald 23 by the force F. If no force is applied to the heald 23 ( Figure 3A ), the sensor 30 will not measure any deformation, so the measured relative force is zero; however, if the force F ( Figure 3B ), the sensor 30 measures the deformation of the heald rope 23 and measures the output force F.

[0045] According to one embodiment, Figure 4 As shown, each sensor 30 comprises at least a portion of each heald 23. This heald portion 23 is configured to measure the deformation of the heald 23 caused by the force F exerted by the loom 1 on the heald 23. Preferably, the sensor 30 comprises the entire length of the heald 23, in this way the heald 23 is considered piezoresistive. In addition to the function of transmitting the force from the jacquard loom to the heald 24, the heald 23 also has a measuring function. In this embodiment, the heald 23 assumes the role and function of the sensor 30. This embodiment makes it possible to limit the volume of the loom 1 and to improve the integration of the monitoring device 3 in the loom 1. In addition, the accuracy of the measurement is improved.

[0046] Figure 5 The general steps of a method for monitoring the production of a woven preform by a loom according to one embodiment are shown. The monitoring of the production of the woven preform is carried out on a loom 1. Preferably, the loom 1 is a loom as previously described and consists of Figure 1 The loom 1 used comprises the loom 1 as described above and is composed of Figure 2 A heald frame 2 is shown. The heald frame 2 comprises a plurality of healds 23 for connecting the jacquard mechanism to healds 24 for lifting the warp yarns 40. The healds 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 healds 23, which are then driven by the jacquard mechanism. According to the weaving program, each hook is controlled to apply a force F on the heald 23 to which the hook is connected. During the step of applying the force F to one (or more) healds 23, the internal tension of the heald 23 increases, and the force F is transmitted to the heald 24 connected to the heald 23. Then, the sensor 30 connected to the heald 23 (to which the force is applied) measures the force applied to the heald 23 by E1 by measuring the deformation caused by the displacement of the heald 23. As described above, the end of each sensor 30 is connected to one of the healds 23, and the change in the tension of the heald 23 caused by the application of the force is measured by the sensor 30. The jacquard mechanism can actuate multiple control hooks at the same time, and then multiple healds 23 are subjected to the force F, and then the sensors 30 fixed to these healds 23 measure the force applied to the multiple healds 23 by E1.

[0048] This measurement result is then transmitted via the connection line 32 connecting each sensor 30 to the processing unit 31. The processing unit 31 analyses E2 the data received by the plurality of sensors 30 to identify manufacturing anomalies on at least one or more of the healds 23.

[0049] According to one embodiment, the processing unit 31 is suitable for sending E3 to the weaving machine 1 instructions resulting from an analysis E2 of the deformation of each heald 23 to which the sensor 30 is connected. This makes it possible to improve the weaving method and possibly avoid greater degradation of the weaving machine and / or the weaving preform.

Claims

1. A system comprising: - a heald frame (2) for a loom (1), the loom comprising a plurality of healds (24), the heald frame (2) comprising a collector (21), a lashing plate (22), and a plurality of healds (23) guided by the lashing plate (22) and the collector (21), each of the plurality of healds (23) being designed to be connected to one of the plurality of healds (24) of the loom (1); and - a monitoring device (3), which is used to monitor the production of woven preforms by the loom (1), and the monitoring device (3) comprises: - a plurality of sensors (30), each sensor (30) of the plurality of sensors being connected to a heald (23) of the plurality of healds (23) and being configured to measure the heald (23) deformation caused by a force applied by the loom (1) to the heald rope (23) to which the sensor (30) is connected; and - a processing unit (31) connected to the plurality of sensors (30) and configured to analyse the deformations to identify manufacturing anomalies on at least one heald (23).

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

3. The system according to any one of claims 1 to 2, wherein: The processing unit (31) is configured to analyze the deformation throughout the manufacturing process of the braided preform.

4. The system according to any one of claims 1 to 3, wherein: Each sensor (30) of the plurality of sensors (30) comprises a strain gauge, and preferably, the sensor (30) is a piezoelectric sensor.

5. The system according to any one of claims 1 to 4, wherein: Each sensor (30) of the plurality of sensors (30) comprises two ends, each of the two ends being fixed to the heald rope (23) by an adhesive element so that the sensor (30) extends along the heald rope (23), preferably, the adhesive element comprises resin.

6. The system according to any one of claims 1 to 4, wherein: Each sensor (30) of the plurality of sensors (30) is fixed to the heald rope (23) to form a junction between two sections of the heald rope (23).

7. The system according to any one of claims 1 to 6, wherein: Each sensor (30) of the plurality of sensors (30) is located on the heddle (23) to extend between the lashing plate (22) and the collector (21).

8. The system according to any one of claims 1 to 4, wherein: Each sensor (30) of the plurality of sensors (30) comprises at least a portion of the heddle (23), and at least a portion of the heddle (23) is configured to measure a deformation of the heddle (23) caused by a force applied to the heddle (23) by the loom (1).

9. The system according to any one of claims 1 to 8, wherein: The processing unit (31) is configured to send instructions to the loom (1), wherein the instructions are derived from the analysis of the deformation.

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