Motion control method for digital three-dimensional knitting yarn carrier

Abstract

The invention relates to a motion control method for a digital three-dimensional knitting yarn carrier. The motion control method comprises the following steps: S1, encoding the yarn carrier and a shaft yarn position; s2, planning the knitting chassis to enable the yarn carriers to be fully distributed on the whole knitting module, setting a corner wheel rotation time sequence, dividing the rotation states of the corner wheels into two groups according to the corner wheel rotation time sequence, and respectively defining the two groups as a corner wheel state matrix and a corner wheel state matrix; s3, according to a corner wheel rotation time sequence on the knitting chassis, storing the initially arranged yarn carrier number matrix into an arrangement matrix for recording the movement of the yarn carriers in each step; then carrying out traversal operation on the corner wheel state matrix and the corner wheel state matrix; after a corner wheel rotation period is completed, the positions of all the yarn carriers and the shaft yarn on the knitting chassis are changed, and coordinates of track points passed by the yarn carriers when the yarn carriers move on the knitting chassis are obtained. The motion trail of the yarn carrier is controlled through an algorithm, and the knitting efficiency and the finished product quality are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of digital three-dimensional weaving, and more specifically to a motion control method of a digital three-dimensional weaving yarn carrier. Background Art

[0002] A 3D braiding yarn carrier is a tool used to manufacture 3D braided structures. It can interweave multiple yarns to form a complex 3D structure. In traditional braiding processes, 2D braiding machines are usually used for weaving, while the use of 3D braiding yarn carriers can achieve more complex structures and higher design freedom. In traditional braiding machines, the movement of the yarn carrier is usually controlled by a mechanical system. However, this mechanical control system often has difficulty in achieving complex 3D braiding movements and may result in unstable quality of the braided fabric. With the development of digital technology, digital braiding technology has gradually emerged, which can improve braiding efficiency and precision.

[0003] At present, some digital control algorithms are known to be used in weaving machines to control the movement of yarn carriers in a two-dimensional plane. However, these technologies are usually difficult to achieve complex weaving movements in three-dimensional space. The motion algorithm of a three-dimensional weaving yarn carrier is difficult to achieve accurate yarn carrying path planning and real-time adjustment of the motion trajectory. During the weaving process, the yarn carrier needs to move according to a pre-set path to ensure the accuracy and precision of the yarn carrying. Traditional path planning algorithms are mainly based on mathematical models and planning algorithms, but in the movement of three-dimensional weaving yarn carriers, considering factors such as the complexity of the weaving structure and the motion range of the yarn carrier, the traditional path planning algorithm needs to be improved and optimized. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a digital three-dimensional weaving yarn carrier motion control method, which realizes the accurate carrying and placement of yarn during the three-dimensional weaving process, thereby improving the weaving efficiency and the quality of the finished product.

[0005] The technical solution adopted by the present invention to solve the technical problem is: construct a digital three-dimensional weaving yarn carrier motion control method, which is used for a rotary weaving machine with a rectangular arrangement of corner wheels, wherein the rectangular arrangement is that the corner wheels are arranged in an n×n square on the chassis, and the yarn carrier is controlled by the rotation of the corresponding corner wheel, and each corner wheel is equipped with an independently moving motor. The control method includes the following steps:

[0006] S1. A plane rectangular coordinate system is established based on a single-module knitting prototype arranged in an n×n square, and the positions of the yarn carriers and the axial yarns during multi-module knitting are recorded. Based on a 3×3 module splicing scheme, the positions of the yarn carriers and the axial yarns are encoded;

[0007] S2. Plan the braiding chassis so that the yarn carrier covers the entire braiding module, and set the rotation sequence of the angle wheel. According to the rotation sequence of the angle wheel, the rotation state of the angle wheel is divided into two groups. One group of angle wheels rotates 90° clockwise, and the other group of angle wheels rotates 90° counterclockwise. They are defined as the angle wheel state matrix [hornStateM1] and the angle wheel state matrix [hornStateM2] respectively. Define the number of angle wheel rotation cycles as the variable braidingStep. Assigning a value to the variable will determine the number of movement steps of the yarn carrier, thereby controlling the length of the braided fabric.

[0008] S3. According to the rotation state of the angle wheel, the position coordinates of the yarn carrier and the axial yarn are transformed; according to the rotation sequence of the angle wheel on the weaving chassis, the initially arranged yarn carrier number matrix carrierNumM is stored in a matrix allCarrierStep that records the arrangement of the yarn carrier after each step of movement; then the angle wheel state matrix [hornStateM1] and the angle wheel state matrix [hornStateM2] are traversed; the position transformation of all the yarn carriers and the axial yarn on the weaving chassis is completed after one angle wheel rotation cycle, and the coordinates of the trajectory points passed by the yarn carrier when moving on the weaving chassis are obtained.

[0009] In the above scheme, step S3 includes the following steps:

[0010] (1) Add the current carrier number matrix carrierNumM to the end of the three-dimensional matrix allCarrierStep, check whether the elements in carrierNumM change with the horn wheel state matrix hornSrateM1, if the change occurs, store the changed coordinates, update carrierNumM, and proceed to the next step;

[0011] (2) Store carrierNumM at the end of allCarrierStep, check whether the elements in carrierNumM change with the horn wheel state matrix hornSrateM2, and if so, store the changed coordinates, update carrierNumM, and proceed to the next step;

[0012] (3) If the number of corner wheel motion cycles n is equal to the periodic variable braidingStep, all elements in allCarrierStep are discretized according to the number of discrete points discretePointCount.

[0013] In the above scheme, in step S1, the upper left corner of the knitting machine chassis is set as the coordinate origin, the horizontal and vertical directions are set as the positive directions of the x-axis and the y-axis, and the unit length in the coordinate system is set to half the center distance between two adjacent corner wheels. The unit length is the radius of the circular arc trajectory when the yarn carrier moves around the corner wheel.

[0014] In the above scheme, in step S1, the yarn carriers of the common part when the modules are spliced ​​horizontally are encoded according to the module coding rules arranged on the right, and the yarn carriers of the common part when the modules are spliced ​​vertically are encoded according to the module coding rules arranged at the bottom.

[0015] In the above scheme, the corner wheel state matrix [hornStateM1] and the corner wheel state matrix [hornStateM2] are as follows:

[0016]

[0017] When the state of the corner wheel is "1", the corner wheel rotates 90° clockwise; when the state of the corner wheel is "-1", the corner wheel rotates 90° counterclockwise.

[0018] In the above scheme, the angle wheel state matrix [hornStateM1] and the angle wheel state matrix [hornStateM2], each element of which represents an angle wheel, each angle wheel drives a different yarn carrier; according to the arrangement rule of the angle wheels and the yarn carriers on the knitting machine chassis, the positions of the four yarn carriers driven by the elements (i, j) (i=0, 1, 2..., j=0, 1, 2...) in the angle wheel state matrix and the axis yarn at the center thereof in the yarn carrier number matrix carrierNumM are listed in formulas (1)-(5); according to the rotation state of the angle wheel, the position coordinates of the yarn carrier and the axis yarn are transformed;

[0019] upCarrier=(2i,2j+1) (1)

[0020] downCarrier=(2i+2,2j+1) (2)

[0021] leftCarrier=(2i+1,2j) (3)

[0022] rightCarrier=(2i+1,2j+2) (4)

[0023] axialYarn=(2i+1,2j+1) (5).

[0025] The implementation of the digital three-dimensional weaving yarn carrier motion control method of the present invention has the following beneficial effects:

[0026] The present invention combines three-dimensional weaving technology and yarn carrier motion control technology, and controls the motion trajectory of the yarn carrier through an algorithm, thereby clearly displaying the motion trajectory of the yarn carrier on the weaving chassis, obtaining the movement law of the yarn carrier, and then describing the motion trajectory of the yarn in space, thereby achieving accurate carrying and placement of the yarn in the three-dimensional weaving process, thereby improving the weaving efficiency and the quality of the finished product. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0028] Figure 1 Obtaining a flow chart for the yarn carrier motion trajectory points;

[0029] Figure 2 It is a schematic diagram of a 2×2 module splicing knitting machine;

[0030] Figure 3 It is a schematic diagram of the rectangular coordinate system of the chassis of a single-module braiding machine;

[0031] Figure 4 It is a schematic diagram of the geometric relationship on a single corner wheel;

[0032] Figure 5 It is a schematic diagram of horizontal or vertical splicing of modules;

[0033] Figure 6 It is a schematic diagram of the coding rules when the modules are spliced ​​horizontally or vertically;

[0034] Figure 7 It is a schematic diagram of the initial trajectory points and the discrete trajectory points of the yarn carrier;

[0035] Figure 8 Schematic diagram of the coordinates of the trajectory points of the yarn carrier before and after discreteness. DETAILED DESCRIPTION

[0036] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described in detail with reference to the accompanying drawings.

[0037] The present invention discloses a flow chart of a method for controlling the motion of a digital three-dimensional weaving yarn carrier. Figure 1 shown.

[0038] For the actual production of three-dimensional braided fabrics, the actual size often requires the braiding machine to be able to arrange enough yarn carriers in the length and width directions. Therefore, the braiding machine is modularly expanded, showing a 2×2 module splicing scheme (n×n module splicing and so on), such as Figure 2 After the knitting machine modules to be used are spliced ​​together, the edge of the chassis is closed with a limit plate to expand the yarn carrier capacity of the knitting machine.

[0039] The corner wheels of the single-module braiding machine are arranged in 6×6. In order to more clearly express the positional relationship between the yarn carrier and the shaft yarn, a plane rectangular coordinate system is established for the designed single-module braiding prototype. In order to ensure that the coordinates of all yarn carriers and shaft yarns on the braiding chassis are non-negative integers, the upper left corner of the braiding machine chassis is set as the coordinate origin, and the horizontal and vertical directions are set as the positive directions of the x-axis and y-axis, such as Figure 3 To ensure that the coordinates of all yarn carriers and shaft yarns are integers, the unit length in the coordinate system is set to half the distance between the centers of two adjacent corner wheels. The geometric relationship on a single corner wheel is shown in Figure 4 As shown, the unit length r in the coordinate system is the radius of the arc trajectory when the yarn carrier moves around the corner wheel. It is defined as a variable traceRadius, and the size of the corner wheel radius can be reflected by defining the size of this value.

[0040] This algorithm is based on a 3×3 module splicing scheme to encode the positions of the yarn carrier and the shaft yarn. To facilitate reading the specific positions of the two on the chassis, both are encoded with five digits (universality). Taking a weaving module as an example, the numbering matrix of the yarn carrier and the shaft yarn is shown in formula (1). In the formula, the encoding method of the yarn carrier is: taking 11001 as an example, the first two digits indicate that the module is the module of the first row and the first column in the 3×3 splicing module, and the last three digits indicate the sequence number of the yarn carrier in the module, which increases from left to right and from top to bottom. It can be seen that there are 84 yarn carriers in a module, and the code of the 84th yarn carrier is 11084; the encoding method of the axial yarn is: since the axial yarn is placed at the center of the angle wheel, the arrangement of the axial yarn in a single braiding machine module is consistent with the arrangement of the angle wheel, both of which are 6×6 arrangements. Therefore, the position of the axial yarn in the 6×6 arrangement is used to encode it. Taking 11110 as an example, the first two digits also indicate the position of the module in the 3×3 splicing module, and the last three digits indicate that the axial yarn is located in the first row and the first column in the 6×6 arrangement of the single module. It can be seen that the axial yarn in a module is arranged in 6×6 from 11110 in the upper left corner to 11660 in the lower right corner, with a total of 36 axial yarns.

[0041]

[0042] When the modules are spliced, there is a situation where one row or one column of yarn carriers is shared between two modules, such as Figure 5 Therefore, in order to unify the coding rules of the yarn carriers, the yarn carriers of the shared parts when the modules are horizontally spliced ​​are coded according to the coding rules of the modules arranged on the right, as shown in Figure 6As shown, when module 11 and module 12 are spliced ​​horizontally, the yarn carrier of the common part is encoded according to the coding rule of module 12; when they are spliced ​​vertically, the yarn carrier of the common part is encoded according to the coding rule of the module arranged below; when module 11 and module 21 are spliced ​​vertically, the yarn carrier of the common part is encoded according to the coding rule of module 21.

[0043] The yarn carrier and the spool yarn are encoded according to the above encoding rules, and the data therein is stored in the yarn carrier number matrix carrierNumM, so as to facilitate the subsequent reading of the position of the yarn carrier.

[0044] Before analyzing the movement law of the yarn carrier on the chassis, it is necessary to determine the arrangement of the yarn carrier on the weaving chassis, the rotation sequence of the horn wheel, and the number of rotation cycles of the horn wheel. Here, the weaving chassis is planned as a yarn carrier that covers the entire weaving module. Since the movement of the yarn carrier depends on the rotation state of the horn wheel, the rotation state of the horn wheel is divided into two groups according to the rotation sequence of the horn wheel, namely: one group of horn wheels rotates 90° clockwise, and the other group of horn wheels rotates 90° counterclockwise; they are defined as the horn state matrix [hornStateM1] and the horn state matrix [hornStateM2], respectively. As shown in formula numbers (2) and (3), when the horn wheel state is "1", the horn wheel rotates 90° clockwise, and when the horn wheel state is "-1", the horn wheel rotates 90° counterclockwise. The number of rotation cycles of the horn wheel is defined as the variable braidingStep. Assigning a value to this variable will determine the number of steps of the yarn carrier, thereby controlling the length of the braided fabric.

[0045]

[0046] In the horn state matrix [hornStateM1] and the horn state matrix [hornStateM2], each element represents a horn, and each horn drives a different yarn carrier. Therefore, the elements in the horn state matrix and the elements in the yarn carrier number matrix must be matched to obtain the position of the yarn carrier driven by each horn in the yarn carrier number matrix carrierNumM. According to the arrangement of the horn and the yarn carrier on the knitting machine chassis, the positions of the four yarn carriers driven by the elements (i, j) (i = 0, 1, 2 ..., j = 0, 1, 2 ...) in the horn state matrix and the axis yarn at the center thereof in the yarn carrier number matrix carrierNumM are listed in formulas (4) to (8).

[0047] upCarrier=(2i,2j+1) (4)

[0048] downCarrier=(2i+2,2j+1) (5)

[0049] leftCarrier=(2i+1,2j) (6)

[0050] rightCarrier=(2i+1,2j+2) (7)

[0051] axialYarn=(2i+1,2j+1) (8)

[0052] According to the rotation state of the angle wheel, the position coordinates of the yarn carrier and the axial yarn are transformed. The transformation rule is shown in Table 1. The yarn carrier rotates clockwise or counterclockwise under the drive of the adjacent angle wheel, and its position coordinates are successively transformed into the position coordinates of the next yarn carrier adjacent to itself, while the position coordinates of the axial yarn that coincides with the center coordinates of the angle wheel remain unchanged. The yarn carrier number matrix carrierNumM is transformed according to the above coordinate transformation rule, thereby establishing the transformation relationship between the angle wheel rotation state matrix and the yarn carrier number matrix.

[0053] After establishing the influence of a single angle wheel on the position coordinates of all yarn carriers in the yarn carrier numbering matrix, according to the rotation sequence of the angle wheel on the weaving chassis, the yarn carrier numbering matrix (two-dimensional matrix) of the initial arrangement is first stored in a matrix allCarrierStep (three-dimensional matrix) that records the arrangement of the yarn carrier after each step of movement as the first element of the three-dimensional matrix; then the angle wheel state matrix [hornStateM1] is traversed, and the position of the angle wheel with a state of "1" in the angle wheel state matrix is ​​output, and according to the position, according to the transformation rule of the angle wheel state on the yarn carrier position coordinates in Table 1, the yarn carrier numbering matrix carrierNumM representing the arrangement of the yarn carriers on the current weaving chassis represented by the last element in the three-dimensional matrix allCarrierStep is transformed, and the new yarn carrier numbering matrix carrierNumM obtained after the coordinate transformation is stored again in the three-dimensional matrix allCarrierStep as the last element of the three-dimensional matrix; then the angle wheel state matrix [hornStateM2] is transformed. The position of the angle wheel with the state of "-1" in the angle wheel state matrix is ​​output, and the coordinate transformation of the yarn carrier number matrix carrierNumM represented by the last element of the three-dimensional matrix allCarrierStep that reflects the current yarn carrier position arrangement is also performed, and the new yarn carrier number matrix carrierNumM obtained after the coordinate transformation is also stored in the three-dimensional matrix allCarrierStep and used as its last element; for the position coordinates representing the axial yarn in carrierNumM, since the axial yarn does not move with the angle wheel, it is only necessary to keep the coordinate unchanged; at this point, the position transformation of all yarn carriers and axial yarns on the weaving chassis after one angle wheel rotation cycle is completed, and finally, the above operation is looped, and the number of loops is the set number of angle wheel rotation cycles. After all loops are completed, the coordinates of the trajectory points passed by the yarn carrier when moving on the weaving chassis can be obtained by reading the position of a coded yarn carrier in each yarn carrier number matrix carrierNumM in the three-dimensional matrix allCarrierStep.

[0054] Table 1 The influence of the rotation state of the angle wheel on the position change of the yarn carrier

[0055]

[0056] After the above motion algorithm, the coordinates of the trajectory points of the yarn carrier are orthogonally distributed around the corner wheel. However, when the yarn carrier moves with the corner wheel, its plane trajectory is not as Figure 7 Instead of jumping directly from the previous trajectory point to the next trajectory point along a straight line as shown in (a), it gradually moves to the next point along a circular trajectory, such as Figure 7As shown in (b), it is necessary to perform discrete operations on two adjacent trajectory points in the initial coordinates of the yarn carrier to obtain a yarn trajectory that is closer to the actual state.

[0057] Traverse the trajectory points in the non-discrete carrier number matrix carrierNumM, take out two adjacent trajectory points in turn, define the variable discretePointCount to represent the number of discrete trajectory points inserted between two adjacent carrier trajectory points, and divide the arc trajectory of a quarter circle between two adjacent carrier trajectory points into equal parts according to the number of discrete trajectory points. Figure 8 (b) shows the discrete state of the yarn carrier trajectory when the variable discretePointCount takes the value of 2. The discrete trajectory points are inserted into the yarn carrier number matrix carrierNumM according to their actual positions, and finally a matrix is ​​obtained that can more accurately represent the motion trajectory of the yarn carrier. Figure 8 The coordinates of the track points of the yarn carrier coded as "11001" before and after the track is discretized are given when the number of rotation cycles of the angle wheel braidingStep is 10 and the arc track radius of the yarn carrier (that is, the unit length of the coordinate system) traceRadius is 1 in a single braiding module "11". Figure 8 In (a), after removing the initial arrangement coordinates (1,0) of the yarn carrier, there are a total of 20 trajectory points, which is consistent with the result when the braidingStep value is 10. Figure 8 (b) can be regarded as Figure 8 In (a), two discrete points are evenly inserted between two adjacent trajectory points, which conforms to the actual situation and completes the discretization of the trajectory points of the yarn carrier, which can more realistically reflect the actual motion trajectory of the yarn carrier.

[0058] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A digital three-dimensional weaving yarn carrier motion control method, used for a rotary weaving machine with rectangular arrangement of corner wheels, wherein the rectangular arrangement is that the corner wheels are arranged in an n×n square on the chassis, and the yarn carrier is controlled by the rotation of the corresponding corner wheel, and each corner wheel is equipped with an independently moving motor, characterized in that: The control method comprises the following steps: S1. A plane rectangular coordinate system is established based on a single-module knitting prototype arranged in an n×n square, and the positions of the yarn carriers and the axial yarns during multi-module knitting are recorded. Based on a 3×3 module splicing scheme, the positions of the yarn carriers and the axial yarns are encoded; S2. Plan the braiding chassis so that the yarn carrier covers the entire braiding module, and set the rotation sequence of the angle wheel. According to the rotation sequence of the angle wheel, the rotation state of the angle wheel is divided into two groups. One group of angle wheels rotates 90° clockwise, and the other group of angle wheels rotates 90° counterclockwise. They are defined as the angle wheel state matrix [hornStateM1] and the angle wheel state matrix [hornStateM2] respectively. Define the number of angle wheel rotation cycles as the variable braidingStep. Assigning a value to the variable will determine the number of movement steps of the yarn carrier, thereby controlling the length of the braided fabric. S3. According to the rotation state of the angle wheel, the position coordinates of the yarn carrier and the axial yarn are transformed; according to the rotation sequence of the angle wheel on the weaving chassis, the initially arranged yarn carrier number matrix carrierNumM is stored in a matrix allCarrierStep that records the arrangement of the yarn carrier after each step of movement; then the angle wheel state matrix [hornStateM1] and the angle wheel state matrix [hornStateM2] are traversed; the position transformation of all the yarn carriers and the axial yarn on the weaving chassis is completed after one angle wheel rotation cycle, and the coordinates of the trajectory points passed by the yarn carrier when moving on the weaving chassis are obtained.

2. The digital three-dimensional weaving yarn carrier motion control method according to claim 1 is characterized in that: The step S3 comprises the following steps: (1) Add the current carrier number matrix carrierNumM to the end of the three-dimensional matrix allCarrierStep, check whether the elements in carrierNumM change with the horn wheel state matrix hornSrateM1, if the change occurs, store the changed coordinates, update carrierNumM, and proceed to the next step; (2) Store carrierNumM at the end of allCarrierStep, check whether the elements in carrierNumM change with the horn wheel state matrix hornSrateM2, and if so, store the changed coordinates, update carrierNumM, and proceed to the next step; (3) If the number of corner wheel motion cycles n is equal to the periodic variable braidingStep, all elements in allCarrierStep are discretized according to the number of discrete points discretePointCount.

3. The digital three-dimensional weaving yarn carrier motion control method according to claim 1 is characterized in that: In step S1, the upper left corner of the knitting machine chassis is set as the coordinate origin, the horizontal and vertical directions are set as the positive directions of the x-axis and the y-axis, and the unit length in the coordinate system is set to half the center distance between two adjacent corner wheels. The unit length is the radius of the circular arc trajectory when the yarn carrier moves around the corner wheel.

4. The digital three-dimensional weaving yarn carrier motion control method according to claim 1 is characterized in that: In step S1, the yarn carriers of the common part when the modules are spliced ​​horizontally are encoded according to the module coding rule arranged on the right, and the yarn carriers of the common part when the modules are spliced ​​vertically are encoded according to the module coding rule arranged on the bottom.

5. The digital three-dimensional weaving yarn carrier motion control method according to claim 1 is characterized in that: The corner wheel state matrix [hornStateM1] and the corner wheel state matrix [hornStateM2] are as follows: When the state of the corner wheel is "1", the corner wheel rotates 90° clockwise; when the state of the corner wheel is "-1", the corner wheel rotates 90° counterclockwise.

6. The digital three-dimensional weaving yarn carrier motion control method according to claim 5 is characterized in that: The angle wheel state matrix [hornStateM1] and the angle wheel state matrix [hornStateM2], each element of which represents an angle wheel, and each angle wheel drives a different yarn carrier; according to the arrangement of the angle wheels and the yarn carriers on the knitting machine chassis, the positions of the four yarn carriers driven by the elements (i, j) (i=0, 1, 2..., j=0, 1, 2...) in the angle wheel state matrix and the axis yarn at the center thereof in the yarn carrier number matrix carrierNumM are listed in formulas (1)-(5); according to the rotation state of the angle wheel, the position coordinates of the yarn carrier and the axis yarn are transformed; upCarrier=(2i,2j+1) (1) downCarrier=(2i+2,2j+1) (2) leftCarrier=(2i+1,2j) (3) rightCarrier=(2i+1,2j+2) (4) axialYarn=(2i+1,2j+1) (5).

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