A control method for full-automatic track changing of a stretcher

Abstract

The present application belongs to the technical field of stretching machine variable track, and discloses a control method for full-automatic variable track of a stretching machine. For a synchronous stretching machine with the initial longitudinal stretching ratio as the maximum value, the stretching machine is divided into a forward chain track state and a return chain track state, the theoretical measurement values of the forward track gauge, the return track gauge, the outlet chain wheel disc offset and the return chain clamp quantity at different positions of the stretching zone corresponding to an arbitrary target longitudinal stretching ratio r are calculated, the motor is driven according to the above parameters, and the full-automatic variable track of the synchronous stretching machine is realized. When the automatic variable track is performed, the interval from r0 to r is subdivided into small intervals with an interval of 0.1; the motor is driven, the forward track gauge, the return track gauge and the outlet chain wheel disc offset are controlled to run to the target values in the small intervals in the same time, and the deviation between the theoretical measurement value N 测 of the return chain clamp quantity and the actual measurement value is within the permitted range, then the next small interval is continuously executed until the target value is reached.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of stretcher variable gauge, in particular to a control method for full-automatic variable gauge of a stretcher. BACKGROUND

[0002] When adjusting the longitudinal stretching ratio of the stretcher, the gauge of the process guide rail needs to be adjusted, and the change of the gauge of the process guide rail will cause the change of the total number of process chain clamps. Therefore, the gauge of the exit and entry sprocket and the return guide rail needs to be adjusted to match the change of the number of process chain clamps.

[0003] The stretchers on the current market can only adjust the longitudinal stretching ratio in the offline state, and there is no stretcher device that can realize online real-time adjustment of the longitudinal stretching ratio.

[0004] Therefore, in order to improve the flexibility of the stretching ratio adjustment of the stretcher and avoid the impact of shutdown on production efficiency, a control method for full-automatic variable gauge of a stretcher needs to be developed. SUMMARY

[0005] The purpose of the present application is to realize online automatic adjustment of the stretching ratio of the stretcher, and a control method for full-automatic variable gauge of a stretcher is designed.

[0006] The technical solution of the present application is as follows: a control method for full-automatic variable gauge structure of a stretcher, for a synchronous stretcher with an initial longitudinal stretching ratio r 初 being the maximum value, which is divided into a process chain rail state and a return chain rail state, the process gauge D1, D2, D3, D4 and the return gauge D out , the exit sprocket disc offset K and the theoretical measurement value N 测 of the return chain clamp number corresponding to any target longitudinal stretching ratio r are calculated, and the above parameters are used to drive the motor to realize full-automatic variable gauge of the synchronous stretcher.

[0007] First, a database composed of a mapping group from the return gauge D out to the return chain clamp number N out is established, a function relationship from the return gauge D out to the return chain clamp number N out is established by the method of polynomial fitting, and the return chain clamp number N out corresponding to the target longitudinal stretching ratio r is substituted into the function relationship formula to solve the return gauge D out corresponding to the target longitudinal stretching ratio r.

[0008] The continuously changing longitudinal target stretching ratio r is discretized to obtain several groups of function relationships about the process gauge D1, D2, D3, D4, the target stretching ratio r and the return gauge D out- target stretch ratio r, outlet chain wheel disc offset K - target stretch ratio r, theoretical measurement value N of return chain clip quantity 测 - data of target stretch ratio r; the data is established by function relationship through polynomial fitting method, and finally the process track D1, D2, D3, D4 and return track D under any target stretch ratio r are obtained out , outlet chain wheel disc offset K, and theoretical measurement value N of return chain clip quantity 测 ;

[0009] When the operation of the synchronous stretcher starts to execute automatic track changing, first, the target longitudinal stretch ratio r is input, the stretch ratio before track changing is r0, in order to ensure that the process track D1, D2, D3, D4 and return track D out , outlet chain wheel disc offset K can keep synchronous at any time, the interval from r0 to r is subdivided into small intervals with interval of 0.1; then the driving motor is driven to control the process track D1, D2, D3, D4 and return track D out , outlet chain wheel disc offset K runs to the target value in the interval at the same time in each small interval, and then after stable operation for a period of time, the deviation of the theoretical measurement value N of the return chain clip quantity 测 from the actual measurement value is within the permitted range, then the next small interval is continued to execute until the target longitudinal stretch ratio r reaches the target value.

[0010] The process chain track state of the synchronous stretcher is equivalent to the combination of triangle and straight line when r 初 is the maximum value, the triangle area is the stretching area, the length of each chain clip is L, and the distance between two clips before entering the stretching area is S0;

[0011] For any stretch ratio r, D1, D2, D3, D4 represent the track distance of the stretching area controlled by the motor corresponding to the target longitudinal stretch ratio r, and S represents the distance between adjacent two clips when the film is separated from the chain clip corresponding to the target longitudinal stretch ratio r;

[0012] For any target longitudinal stretch ratio r, there are

[0013]

[0014] D1, D2, D3, D4 are set to be uniformly decreased;

[0015]

[0016] At the initial stretch ratio r 初 , the state is

[0017] S 初 = 2L (1-5)

[0018] D4initial= 0 (1-6)

[0019] D1 at the beginning=D1 (1-7)

[0020]

[0021] Point C is the reference point before the chain clamp enters the stretching zone, and point D is the reference point before entering the exit sprocket and after the diaphragm separates from the chain clamp.

[0022] At the initial stretch ratio r 初 Under the given conditions, calculate the track parameters from point C to point D based on the initial values ​​of D1, D2, D3, and D4; starting from point C, draw the chain clamp between the two tracks;

[0023] At the initial stretch ratio r 初 Under these conditions, count the number of chain clamps between points C and D and round up to obtain the initial stretch ratio r. 初 The number of integers n in the process chain in the state in early;

[0024] At the initial stretch ratio r 初 In this state, the distance from the nearest chain clip to the right of point D to point D is L. in Initially; let the initial stretch ratio r be... 初 The number of process chains in the state is:

[0025]

[0026] The number of process chain segments N in Initially a non-integer value, representing the number of non-integer chain links between points C and D.

[0027] The return track state of the synchronous stretching machine is equivalent to a combination of trapezoidal and straight chain clamps.

[0028] Infrared sensor a is installed near the exit sprocket on the return track of the synchronous stretching machine, and infrared sensor b is installed near the inlet sprocket on the return track of the synchronous stretching machine; select any chain clamp and install a device that can be detected by the infrared sensor on it to ensure that the chain clamp can be detected when it passes through infrared sensor a and infrared sensor b respectively.

[0029] For any target longitudinal tensile ratio r, start the synchronous tensile machine and run it stably. Set the current chain clamp speed to v. When infrared sensor a detects a signal, timing begins; when infrared sensor b detects a signal, timing ends, with a time interval t. Then, the number of chain clamps between the two infrared sensors is measured as follows:

[0030]

[0031] The number of clamps between the two infrared sensors is used for calibration in the control system;

[0032] For any target longitudinal stretch ratio r, A is the reference point before the return chain track spacing starts to increase, and B is the reference point after the return chain track spacing is minimized and before entering the entry sprocket;

[0033] For any target longitudinal stretch ratio r, D out represents the return track spacing controlled by the motor corresponding to the target longitudinal stretch ratio r;

[0034] In the initial stretch ratio r 初 , the return track spacing D out initial is measured;

[0035] In the initial stretch ratio r 初 , the track parameters from A to B are calculated according to D out initial; from A, the chain clip is drawn between the two tracks;

[0036] In the initial stretch ratio r 初 , the number of chain clips between A and B is counted and rounded up to obtain the integer number n 初 of return chain clips in the initial stretch ratio r out initial;

[0037] In the initial stretch ratio r 初 , the distance from the nearest chain clip to the left of B to B is L out initial; the number of return chain clips in the initial stretch ratio r 初 is recorded as

[0038]

[0039] where the number of return chain clips N out initial is a non-integer representing the non-integer number of chain clips between A and B;

[0040] The total number of chain clips does not change, and the number of chain clips at other positions does not change except for the entry chain track and the return chain track, so the total number of chain clips N 总 is a certain value:

[0041] N 总 = N out initial + N in initial (1-13)

[0042] In the initial stretch ratio r 初 , start the synchronous stretcher and stabilize the operation, set the current chain clip speed as v; when infrared sensor a detects a signal, start timing, and when infrared sensor b detects a signal, end timing, the time interval is t 初 , then the number of chain clips between the two infrared sensors is measured

[0043]

[0044] The calculated number of backhaul chain clamps N out The difference between the initial measured number of backhaul chain clamps N 测初 is

[0045] N0=N 测初 -N out initial (1-15)

[0046] For any stretch ratio r, the difference in the number of backhaul chain clamps N0 is a constant value.

[0047] Calculate the target parameters corresponding to any target stretch ratio r: for the process chain track part of the synchronous stretching machine with any stretch ratio r, its equivalent schematic diagram is a combination of two approaching intersecting straight lines and two parallel straight lines;

[0048] For any target longitudinal stretch ratio r, there is

[0049]

[0050] Combine formulas 1-2, 1-3, 1-4, and formula 1-16 to get D1, D2, D3, D4 corresponding to any target longitudinal stretch ratio r;

[0051] For any target longitudinal stretch ratio r, calculate the track parameters from point C to point D according to D1, D2, D3, and D4; starting from point C, draw the chain clamps between the two tracks;

[0052] For any target longitudinal stretch ratio r, count the number of chain clamps between point C and point D and round up to get the integer number of process chain clamps n in corresponding to any stretch ratio r;

[0053] For any target longitudinal stretch ratio r, the distance from the nearest chain clamp to the right of point D to point D is L in ; the number of process chain clamps corresponding to any target longitudinal stretch ratio r is

[0054]

[0055] As the process track expands, the number of process chain clamps also increases, so the exit chain wheel needs to be offset to compensate. The offset of the exit chain wheel is

[0056] K=L(N in -N in initial) (1-18)

[0057] K represents the deviation of the circumference of a point on the exit sprocket pitch circle scanned in the time of performing automatic variable gauge under the premise of keeping the speed of the chain gripper v constant relative to the circumference of the same point scanned in the same time without performing automatic variable gauge;

[0058] For any target longitudinal stretch ratio r, the total number of chain grippers N 总 is a constant value, so the number of return chain grippers corresponding thereto is

[0059] N out = N 总 -N in (1-19)

[0060] For any target longitudinal stretch ratio r, the calculated value of the number of return chain grippers N out is different from the theoretical measured value of the number of return chain grippers N 测 , and the difference N0 is a constant value, so

[0061] N 测 = N out +N0(1-20)。

[0062] Advantages of the present application: when the longitudinal stretch ratio of the synchronous stretcher needs to be adjusted, it is usually necessary to stop and manually adjust the stretcher gauge and chain gripper, and the accuracy of manual adjustment is low, and the phenomenon of jamming the gripper often occurs during operation, and repeated stop and adjustment of the gauge and chain gripper are required. This method has low production efficiency and high labor cost. The present application can automatically change the gauge online in real time during the operation of the synchronous stretcher, and realize online automatic adjustment of the longitudinal stretch ratio of the synchronous stretcher. It can effectively improve the production efficiency, reduce the difficulty of manual operation, and reduce the labor cost. BRIEF DESCRIPTION OF DRAWINGS

[0063] Figure 1 is the equivalent schematic diagram of the process chain track when r 初 is the maximum value;

[0064] Figure 2 is the track parameter case implementation effect diagram under the state of r 初 ;

[0065] Figure 3 is the equivalent schematic diagram of the return chain track;

[0066] Figure 4 is the equivalent schematic diagram of the process chain track for any stretch ratio r;

[0067] Figure 5 is the K-r case implementation effect diagram;

[0068] Figure 6 is the N 测 -r case implementation effect diagram;

[0069] Figure 7 D4-r, D out -r case implementation effect diagram;

[0070] Figure 8 The structure diagram of the synchronous stretcher. DETAILED DESCRIPTION

[0071] A control method for full-automatic track change of a stretcher, the method is suitable for, for a synchronous stretcher with an initial longitudinal stretching ratio r 初 , the process track distance D1, D2, D3, D4 corresponding to any target longitudinal stretching ratio r can be calculated, the return track distance D out , the outlet sprocket disc offset K, and the theoretical measurement value N of the return chain clamp number 测 , then the motor is driven according to the above parameters, and full-automatic track change of the synchronous stretcher is realized. The detailed steps of the control method are as follows:

[0072] 1. Determining the initial longitudinal stretching ratio r 初 of the synchronous stretcher with the maximum value:

[0073] For the process chain track part of the synchronous stretcher with the initial longitudinal stretching ratio r 初 , the equivalent principle diagram is as shown in Figure 1 .

[0074] As shown in Figure 1 , for any stretching ratio r, the length of each chain clamp is L, and the distance between the two clamps before entering the stretching area is S0, which is determined by the chain track structure of the stretcher.

[0075] As shown in Figure 1 , for any stretching ratio r, D1, D2, D3, and D4 represent the track distance of the stretching area controlled by the motor corresponding to the stretching ratio r, and S represents the distance between the adjacent two clamps when the film sheet separates from the chain clamp corresponding to the stretching ratio r.

[0076] As shown in Figure 1 , for any stretching ratio r, there are

[0077]

[0078] As shown in Figure 1 , for any stretching ratio r, there are

[0079]

[0080] In the present embodiment, D1, D2, D3, and D4 are set to be uniformly decreasing. Then, the following can be calculated:

[0081]

[0082] like Figure 1 As shown, at the initial stretch ratio r 初 In this state,

[0083] S 初 =2L (1-5)

[0084] D4 initial = 0 (1-6)

[0085] D1 at the beginning=D1 (1-7)

[0086]

[0087] like Figure 1 As shown, for any stretch ratio r, point C is the reference point before the chain clamp enters the stretch zone, and point D is the reference point before entering the exit sprocket and after the diaphragm separates from the chain clamp.

[0088] like Figure 1 As shown, at the initial stretch ratio r 初 In this state, the track parameters from point C to point D are calculated based on the initial values ​​of D1, D2, D3, and D4. Starting from point C, the chain clamp is drawn between the two tracks. One example implementation shows the following effect: Figure 2 As shown.

[0089] like Figure 1 , Figure 2 As shown, at the initial stretch ratio r 初 Under these conditions, count the number of chain clamps between points C and D and round up to obtain the initial stretch ratio r. 初 The number of integers n in the process chain in the state in early.

[0090] like Figure 1 As shown, at the initial stretch ratio r 初 In this state, the distance from the nearest chain clip to the right of point D to point D is L. in Initially, for ease of subsequent calculations, let the initial stretch ratio be denoted as r. 初 The number of process chains in the state is

[0091]

[0092] The number of process chain segments N in Initially, it can be a non-integer, representing the number of non-integer chain links between points C and D.

[0093] For the return chain section of a synchronous stretching machine with any stretch ratio r, its equivalent schematic diagram is as follows: Figure 3 As shown.

[0094] like Figure 3As shown, in this embodiment, infrared sensor 1 is installed near the outlet sprocket on the return chain of the stretching machine, and infrared sensor 2 is installed near the inlet sprocket on the return chain of the stretching machine. Any chain clamp is selected, and a device capable of being detected by the infrared sensors is installed on it to ensure that the chain clamp can be detected when passing through infrared sensor 1 and infrared sensor 2 respectively.

[0095] like Figure 3 As shown, for any stretch ratio r, the stretching machine is started and runs stably, with the current chain clamp speed set to v. Timing begins when infrared sensor 1 detects a signal and ends when infrared sensor 2 detects a signal, with a time interval of t. The number of chain clamps between the two infrared sensors is then measured as follows:

[0096]

[0097] This measurement is used for calibration in the control system.

[0098] like Figure 3 As shown, for any stretch ratio r, point A is the reference point before the return chain track gauge starts to increase, and point B is the reference point after the return chain track gauge shrinks to its minimum and before entering the inlet sprocket.

[0099] like Figure 3 As shown, for any stretch ratio r, D out This represents the return gauge controlled by the motor corresponding to the stretch ratio r.

[0100] like Figure 3 As shown, at the initial stretch ratio r 初 Under these conditions, the return track gauge D was measured. out early.

[0101] like Figure 3 As shown, at the initial stretch ratio r 初 In the state, according to D out Calculate the initial track parameters from point A to point B. Starting from point A, draw the chain clamp between the two tracks.

[0102] like Figure 3 As shown, at the initial stretch ratio r 初 Under these conditions, count the number of chain clamps between points A and B and round up to obtain the initial stretch ratio r. 初 The integer number n of return link clips in the state out early.

[0103] like Figure 3 As shown, at the initial stretch ratio r 初 In this state, the distance from the nearest chain clip to the left of point B to point B is L. out Initially, for ease of subsequent calculations, let the initial stretch ratio be denoted as r. 初The number of return chain links in the initial state is

[0104]

[0105] Wherein the number of return chain links N out The initial value can be a non-integer, representing the non-integer number of chain links between point A and point B.

[0106] The total number of chain links does not change, and the number of chain links in other positions does not change except for the process chain track and the return chain track, so the total number of chain links N 总 is a constant value

[0107] N 总 =N out initial+N in initial (1-13)

[0108] As shown in Figure 4 , in the initial stretching ratio r 初 , the stretching machine is started and runs stably, and the current chain speed is set to v. When infrared sensor 1 detects a signal, timing starts, and when infrared sensor 2 detects a signal, timing ends, and the time interval is t 初 , then the number of chain links between the two infrared sensors is measured as

[0109]

[0110] The difference between the calculated number of return chain links N out initial and the measured number of return chain links N 测初 is

[0111] N0=N 测初 -N out initial (1-15)

[0112] For any stretching ratio r, the difference in the number of return chain links N0 can be approximately constant.

[0113] 2. Calculate the target parameters corresponding to any target stretching ratio r:

[0114] For the process chain track part of the synchronous stretching machine at any stretching ratio r, the equivalent schematic diagram is shown in Figure 4 .

[0115] As shown in Figure 4 , combined with formula 1-1, for any stretching ratio r, there are

[0116]

[0117] Combined with formulas 1-2, 1-3, 1-4 and formula 1-16, D1, D2, D3 and D4 corresponding to any stretching ratio r can be obtained.

[0118] As shown in Figure 4 , for any stretch ratio r, the track parameters between C and D points are calculated according to D1, D2, D3, D4. From C point, the chain links are drawn between the two tracks.

[0119] As shown in Figure 4 , for any stretch ratio r, the number of chain links between C and D points is counted and rounded up to get the integer number of process chain links n corresponding to any stretch ratio r in .

[0120] As shown in Figure 1 , for any stretch ratio r, the distance from the nearest chain link to the right of D point to D point is L in . The number of process chain links corresponding to any stretch ratio r is

[0121]

[0122] As shown in Figure 4 , Figure 3 , as the process track opens, the number of process chain links also increases, so the exit chain wheel needs to be offset to compensate. The offset of the exit chain wheel is

[0123] K = L (N in -N in initial) (1-18)

[0124] Where K represents the deviation of the circumference of a point on the exit chain wheel indexing circle scanned in the same time relative to the circumference of the same point scanned in the same time without performing automatic orbit change, under the premise of keeping the speed of the chain link v constant.

[0125] As shown in Figure 4 , Figure 3 , for any stretch ratio r, the total number of chain links N 总 is a constant value, so the number of corresponding return chain links is

[0126] N out = N 总 -N in (1-19)

[0127] As shown in Figure 3 , for any stretch ratio r, the difference N0 between the calculated value N out of the number of return chain links and the theoretically measured value N 测 of the number of return chain links is a constant value, then

[0128] N 测 = N out +N0 (1-20)

[0129] As shown in Figure 5As shown, the method adopted in the present embodiment cannot directly derive the track parameters of the return track through the number N out of return chain links out . Therefore, in the present embodiment, a database is first established, which is composed of a mapping from the return track gauge D out to the number N out of return chain links. Then a functional relationship is established from the return track gauge D out to the number N out of return chain links through a polynomial fitting method. Finally, the number N out of return chain links corresponding to the target draft ratio r is substituted into the functional relationship, and the return track gauge D out corresponding to the target draft ratio r is solved.

[0130] In the present embodiment, the continuously changing target draft ratio r is discretized to obtain several sets of data about the process track gauges D1, D2, D3, D4, the target draft ratio r, the return track gauge D out , the target draft ratio r, the outlet chain wheel disc offset K, the target draft ratio r, and the theoretical measurement value N 测 of the number of return chain links. Similarly, the data is fitted through a polynomial fitting method to establish a functional relationship, and finally the process track gauges D1, D2, D3, D4, the return track gauge D out , the outlet chain wheel disc offset K, and the theoretical measurement value N 测 of the number of return chain links under any target draft ratio r are obtained. The implementation effect of one case is shown in Figure 6 , Figure 7 , Figure 5 .

[0131] 3. Control the drawing frame according to the target draft ratio r:

[0132] As shown in Figure 6 , Figure 7 , Figure 5 , when the drawing frame starts to perform automatic track changing, the target draft ratio r is first input, and the draft ratio before track changing is r0. In order to ensure that the process track gauges D1, D2, D3, D4, the return track gauge D out , and the outlet chain wheel disc offset K can keep synchronous at any moment, the interval from r0 to r in Figure 6 , Figure 7 , ​ is subdivided into small intervals with an interval of 0.1. Then the motor is driven to control the process track gauges D1, D2, D3, D4, the return track gauge D out, the export sprocket disc offset K in each small section within the same time to run to the target value within the section, and then after a stable operation for a period of time, if the theoretical measurement value N 测 of the return chain clamp quantity deviates from the actual measurement value within the permitted range, the next small section is continued to be executed until the stretch ratio r reaches the target value.

Claims

1. A control method of a full-automatic rail changing structure of a drawing machine, characterized by, For the synchronous stretching machine with the initial longitudinal stretching ratio r 初 The maximum value, it is divided into the forward chain track state and the return chain track state, the forward track distance D1, D2, D3, D4, the return track distance D out , the outlet chain wheel disc offset K, and the theoretical measurement value N 测 of the return chain clamp quantity corresponding to the arbitrary target longitudinal stretching ratio r are calculated, and the motor is driven according to the above parameters to realize the full-automatic track change of the synchronous stretching machine. First, a database consisting of a mapping from the track gauge D out to the number of chain links N out is established, a functional relationship from the track gauge D out to the number of chain links N out is established by a polynomial fitting method, and then the number of chain links N out corresponding to the target longitudinal stretch ratio r is substituted into the functional relationship, and the track gauge D out corresponding to the target longitudinal stretch ratio r is solved. The continuously changing longitudinal target stretch ratio r is discretely processed to obtain several groups of target stretch ratio r, approach track gauge D1, D2, D3, D4, return track gauge D, outlet chain wheel disc offset K, and return chain clip quantity theoretical measurement value N out - target stretch ratio r, outlet chain wheel disc offset K, return chain clip quantity theoretical measurement value N 测 - data of target stretch ratio r; the data is established in a function relationship through a polynomial fitting method, and finally the approach track gauge D1, D2, D3, D4 and the return track gauge D, outlet chain wheel disc offset K, and return chain clip quantity theoretical measurement value N under any target stretch ratio r are obtained out 测 ; when the operation of the synchronous stretcher starts to execute automatic gauge changing, the target longitudinal stretch ratio r is first input, the stretch ratio before gauge changing is r0, in order to ensure that the approach track gauge D1, D2, D3, D4, return track gauge D out , outlet chain wheel disc offset K can be kept synchronous at any time, the interval from r0 to r is subdivided into small intervals with an interval of 0.1; then the driving motor is controlled to control the approach track gauge D1, D2, D3, D4, return track gauge D out , outlet chain wheel disc offset K to run to the target value in the interval at the same time in each small interval, and then after stable operation for a period of time, the deviation of the theoretical measurement value N 测 of the return chain clip quantity from the actual measurement value is within the permitted range, the next small interval is continued to be executed until the target longitudinal stretch ratio r reaches the target value.​ 2. The control method of the full-automatic rail changing structure of the stretching machine according to claim 1, characterized in that, The chain track state of the synchronous drawing machine is r 初 When the maximum value is reached, it is equivalent to the combination of a triangle and a straight line formed by the chain clamps, and the triangle area is the stretching area; the length of each chain clamp is L, and the distance between the two clamps before entering the stretching area is S0; D1, D2, D3, D4 represent the track gauge of the stretching zone controlled by the motor corresponding to the target longitudinal stretching ratio r, and S represents the distance between the adjacent two chain grippers when the film is separated from the chain gripper corresponding to the target longitudinal stretching ratio r; For any target longitudinal stretching ratio r, there are D1, D2, D3, D4 are set to be uniformly decreasing; At an initial stretch ratio r 初 in the initial state, S 初 = 2L (1-5) D4initial=0 (1-6) D1initial=D1 (1-7) C point is the reference point before the chain gripper enters the stretching zone, and D point is the reference point before entering the exit sprocket and after the film is separated from the chain gripper; At the initial stretch ratio r 初 The orbit parameters from C to D are calculated according to D1ini, D2ini, D3ini, D4ini; from C, the chain clip is drawn between the two orbits; In the initial stretch ratio r 初 The initial stretch ratio r 初 The integer number n in initial; At the initial stretch ratio r 初 The distance from the nearest chain clip to the point D on the right side of the point D is L in The initial stretch ratio r 初 The number of process chain clips in the initial stretch ratio r where N is the number of process chain clamps in is not an integer, indicating the non-integer number of chain clamps between the C and D points.

3. The control method of the full-automatic rail changing structure of the stretching machine according to claim 1, characterized in that, The return chain track state of the synchronous stretching machine is equivalent to the combination of trapezoidal and straight lines; An infrared sensor a is installed near the exit sprocket disc of the return chain track of the synchronous stretching machine, and an infrared sensor b is installed near the entrance sprocket disc of the return chain track of the synchronous stretching machine; optionally, a chain gripper is installed with a device that can be detected by the infrared sensor to ensure that the chain gripper can be detected when passing through the infrared sensor a and the infrared sensor b, respectively; For any target longitudinal stretching ratio r, the synchronous stretching machine is started and runs stably, and the current chain gripper speed is set to v; when the infrared sensor a detects a signal, timing starts, and when the infrared sensor b detects a signal, timing ends, and the time interval is t, then the number of chain grippers between the two infrared sensors is The number of chain grippers between the two infrared sensors is used for calibration in the control; For any target longitudinal stretching ratio r, A point is the reference point before the return chain track track gauge starts to increase, and B point is the reference point after the return chain track track gauge is minimized and before entering the entrance sprocket disc; For any target longitudinal stretch ratio r, D out represents the gauge of the return track controlled by the motor corresponding to the target longitudinal stretch ratio r; In the initial stretch ratio r 初 The track gauge D out initially; At the initial stretch ratio r 初 The orbit parameters from A to B are calculated initially according to D out The orbit parameters from A to B are calculated initially according to D From A point, the chain gripper is drawn between the two tracks; In the initial stretch ratio r 初 The initial stretch ratio r 初 The integer number n out initial; At the initial stretch ratio r 初 The distance from the nearest chain on the left side of point B to point B is L out Initial; The number of return chain clamps in the initial stretch ratio r 初 state wherein the number of chain links N out is not an integer, indicating the non-integer number of chain links between point A and point B; The total number of chain clips does not change, and the number of chain clips in other positions does not change except for the forward chain track and the return chain track, so the total number of chain clips N 总 is a constant value: N 总 = N out initial + N in initial (1-13) In the initial stretching ratio r 初 State, start the synchronous stretching machine and stable operation, set the current chain clamp speed as v; start timing when infrared sensor a detects the signal, end timing when infrared sensor b detects the signal, and the time interval is t 初 Then the measured number of chain clamps between the two infrared sensors is The calculated number of backhaul chain clamps N out The difference between the initial and the measured number of backhaul chain clamps N 测初 is N0= N 测初 - N out Initial (1-15) For any stretching ratio r, the difference in the number of return chain grippers N0 is a constant value.

4. The control method of the full-automatic rail changing structure of the stretching machine according to claim 1, characterized in that, Calculate the target parameters corresponding to any target stretching ratio r: for the process chain track part of the synchronous stretching machine with any stretching ratio r, the equivalent principle diagram is the combination of two approaching intersecting straight lines and two parallel straight lines; For any target longitudinal stretching ratio r, there are According to formula 1-2, 1-3, 1-4 and formula 1-16, D1, D2, D3, D4 corresponding to any target longitudinal stretching ratio r are obtained; For any target longitudinal stretching ratio r, the track parameters from C point to D point are calculated according to D1, D2, D3, D4; from C point, the chain gripper is drawn between the two tracks; For any target longitudinal stretch ratio r, count the number of chain clips between C point and D point and round up to get the integer number of process chain clips n corresponding to any stretch ratio r in ; For any target longitudinal stretch ratio r, the distance from the nearest chain clip to the right of point D to point D is L in ; the number of process chain clips corresponding to any target longitudinal stretch ratio r is As the process track is opened, the number of process chain grippers is also increasing, so the exit sprocket needs to be offset to compensate, and the offset of the exit sprocket is K = L(N in - N in (1-18) Wherein, K represents the deviation of the circumference swept by a point on the exit sprocket indexing circle relative to the circumference swept by the same point in the same time without executing automatic rail change under the premise of keeping the speed of the chain gripper v constant. For any target longitudinal stretch ratio r, the total number of chain clips N 总 is a constant value, so the number of corresponding backhaul chain clips is N out = N 总 - N in (1-19) For any target longitudinal stretch ratio r, the calculated value of the number of backspan chain links N out is set equal to the difference between the theoretical measured value of the number of backspan chain links N 测 N0 N 测 = N out + N0(1 - 20).

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