A pre-opening device for a filter rod making machine and a control method

Abstract

The application discloses a filter rod forming machine pre-opening device and a control method. The device comprises a support frame, a rubber roller, a steel roller mounted on the support frame and a servo motor for driving the steel roller, a pressure adjusting mechanism and a detection control system. The pressure adjusting mechanism comprises a rubber roller mounting plate and a cylinder, and the rubber roller mounting plate is in sliding connection with the support frame. The rubber roller is mounted on the rubber roller mounting plate. The cylinder is mounted on the support frame and has a piston rod connected with the rubber roller mounting plate to drive the rubber roller away from or close to the steel roller. The detection control system comprises a laser range finder and a controller. The laser range finder is mounted on the support frame and located above the tow package. The laser range finder is in electrical connection with the controller, and the controller is in electrical connection with the cylinder. The application can dynamically adjust the opening pressure and significantly improve the opening uniformity.

Description

Technical Field

[0001] This invention relates to the field of tobacco processing technology, specifically to a pre-opening device and control method for a filter rod forming machine. Background Technology

[0002] During the filter rod production process, the filaments in the filament bundle are pulled by the input roller group and enter the filter rod forming machine after passing through a relatively long free path. This excessively long pulling distance has significant drawbacks: when the filaments detach from the filament bundle, they mainly rely on the unidirectional pulling force of the input roller group, which can easily lead to poor opening effect due to uneven force distribution. Unevenly opened filaments will directly affect the stability of key indicators such as the weight, hardness, and circumference of the subsequent filter rods, resulting in product quality fluctuations.

[0003] In addition, existing pre-opening devices are mostly roller groups with fixed gaps or fixed pressures, which cannot adapt to the dynamic changes in height of the filament bundle from top to bottom during the production process. The compaction of the upper, middle and lower layers of the filament bundle is different. If a constant opening pressure is used, the opening degree of different parts of the filament bundle will be inconsistent, which cannot fundamentally solve the problem of opening uniformity.

[0004] Therefore, providing a pre-opening device and control method for a filter rod forming machine is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a pre-opening device and control method for a filter rod forming machine, so as to at least solve one of the aforementioned technical problems.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A pre-opening device for a filter rod forming machine includes a support frame, a rubber roller, a steel roller mounted on the support frame, and a servo motor for driving the steel roller. It also includes: A pressure regulating mechanism includes a rubber roller mounting plate and a cylinder. The rubber roller mounting plate is slidably connected to the support frame. The rubber roller is mounted on the rubber roller mounting plate. The cylinder is mounted on the support frame and its piston rod is connected to the rubber roller mounting plate to drive the rubber roller away from or closer to the steel roller. A detection and control system, comprising a laser rangefinder and a controller, wherein the laser rangefinder is mounted on the support frame and located directly above the wire bundle conveying path; the laser rangefinder is electrically connected to the controller, and the controller is electrically connected to the cylinder.

[0007] Furthermore, the top and bottom of the rubber roller mounting plate have slide rail grooves; the top inner wall and bottom inner wall of the side frame of the support frame are provided with slide rails, and the slide rail grooves are fitted and installed on the slide rails so that the rubber roller mounting plate is slidably connected to the side frame.

[0008] Furthermore, it further includes a connecting column. A connecting groove is opened on the front side of the rubber roller mounting plate, and the connecting column is nested in the connecting groove; the piston rod of the air cylinder is connected to the connecting column.

[0009] Furthermore, the support frame includes two side frames, a front mounting plate and a steel roller mounting plate. The front mounting plate is fixedly connected to the two side frames on its two sides respectively; the air cylinder is installed on the front mounting plate and its piston rod penetrates through the front mounting plate and is threadedly connected to the connecting column; the steel roller mounting plate is fixed at the rear side of the side frame, and the end of the steel roller is installed on the steel roller mounting plate through a bearing.

[0010] The control method using the filter rod forming machine pre-opening device as described above includes the following steps: 1) Height perception: The laser rangefinder real-time monitors the current height h(t) of the tow package at a preset sampling period T and transmits the data to the controller; 2) Deviation calculation: The controller combines the preset initial height H0 of the tow package to calculate the current height deviation e(t) = H0 - h(t) and the deviation change rate e(t); 3) Strategy determination and parameter self-tuning: The controller adopts the fuzzy adaptive PID algorithm, takes the height deviation e(t) and the deviation change rate e(t) as input variables, and through fuzzy inference, the correction amounts of the PID parameters Kp, Ki and Kd are output in real time, and the current proportional coefficient Kp, integral coefficient Ki and differential coefficient Kd are updated; 4) Pressure value calculation: The controller calculates the control increment according to the updated PID parameters and superimposes the feedforward compensation value based on the height deviation to obtain the target pressure control signal u(t); 5) Execution and feedback: The controller outputs a control signal to drive the air cylinder so that the rubber roller presses against the tow with the target pressure, and the actual pressure response of the air cylinder is used as feedback to participate in the closed-loop regulation.

[0011] Furthermore, in the deviation calculation, a preset adjustment dead zone threshold Emax is set; when the calculated height deviation |e(t)| < Emax, the controller keeps the pressure output of the previous cycle unchanged; when |e(t)| ≥ Emax, the subsequent PID operation and pressure regulation are performed.

[0012] Therefore, the present invention provides a pre-opening device and control method for a filter rod forming machine. Compared with the prior art, the present invention has the following beneficial effects: 1) Effectively overcomes static friction and hysteresis during cylinder startup (through strong proportional action under large deviation); 2) Avoids overshoot oscillation during long stroke of the cylinder (through integral separation); 3) Eliminates minute height errors under steady state, achieving high-precision pressure stabilization; 4) Dynamically adjusts opening and closing pressure, significantly improving opening and closing uniformity. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0014] Figure 1 The attached figure is a schematic diagram of the overall structure of a pre-opening device for a filter rod forming machine provided by the present invention; Figure 2 The attached figure is a schematic diagram of the overall structure of a pre-opening device for a filter rod forming machine provided by the present invention from another perspective; Figure 3 The attached figure is a schematic diagram of the structure of the rubber roller mounting plate provided by the present invention; Figure 4 The attached figure is a three-dimensional structural schematic diagram of the connecting column provided by the present invention; Figure 5 The attached figure is a front view of the connecting column provided by the present invention; Figure 6 The attached image is... Figure 5 Sectional view of AA. Detailed Implementation

[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] like Figure 1-6As shown in the figure, this invention discloses a pre-opening device for a filter rod forming machine, including a support frame 1, a rubber roller 2, a steel roller 3 mounted on the support frame 1, a servo motor 4, a pressure adjustment mechanism, and a detection and control system. The servo motor 4 is connected to the steel roller 3 via a coupling to provide precise traction power. The pressure adjustment mechanism includes a rubber roller mounting plate 5 and a cylinder 6. The rubber roller mounting plate 5 is slidably connected to the support frame 1. The rubber roller 2 is mounted on the rubber roller mounting plate 5 via bearings. The cylinder 6 is mounted on the support frame 1, and its piston rod is connected to the rubber roller mounting plate 5 to drive the rubber roller 2 away from or towards the steel roller 3. The detection and control system includes a laser rangefinder 7 and a controller. In this embodiment, the controller is a PLC. The laser rangefinder 7 is mounted on the support frame 1 and located directly above the fiber bundle conveying path. The laser rangefinder 7 is electrically connected to the controller, and the controller is electrically connected to the cylinder 6. This invention can dynamically adjust the opening pressure, significantly improving the opening uniformity.

[0017] Specifically, the top and bottom of the rubber roller mounting plate 5 have slide rail grooves 51; the top inner wall and bottom inner wall of the side frame 11 of the support frame 1 are provided with slide rails, and the slide rail grooves 51 are fitted onto the slide rails so that the rubber roller mounting plate 5 is slidably connected to the side frame 11.

[0018] In some embodiments, a connecting post 8 is also included. A connecting groove 52 is provided on the front side of the rubber roller mounting plate 5. The connecting post 8 is nested in the connecting groove 52. Two symmetrically distributed protrusions are provided on the front side of the connecting groove 52. A groove 81 is provided on the circumferential surface of the connecting post 8. The protrusions are embedded in the groove 81 to achieve connection and position fixation. The piston rod of the cylinder 6 is connected to the connecting post 8.

[0019] Specifically, the support frame 1 includes two side frames 11, a front mounting plate 12, and a steel roller mounting plate 13. The front mounting plate 12 is fixedly connected to the two side frames 11 on both sides to enhance the structural rigidity. In this embodiment, bolt connection can be used for fixing. The cylinder 6 is mounted on the front mounting plate 12 and its piston rod passes through the front mounting plate 12 and is threadedly connected to the connecting column 8. The steel roller mounting plate 13 is fixed to the rear side of the side frames 11, and the end of the steel roller 3 is mounted on the steel roller mounting plate 13 through a bearing.

[0020] This invention also discloses a control method using the pre-opening device of the filter rod forming machine described above, employing a closed-loop control logic of "height sensing - real-time calculation - pressure compensation". The laser rangefinder 7 collects real-time data on the height of the filament bundle, which is then processed by the PLC controller to output a control signal to drive the cylinder 6, causing the rubber roller 2 to press against the filament bundle with the target pressure. Addressing the nonlinear friction and hysteresis effects of the pneumatic actuator, as well as the nonlinear distribution characteristics of the filament bundle stacking density, a fuzzy adaptive PID control strategy is adopted, including the following steps: Data acquisition and preprocessing are performed, including setting the sampling period T. T is set to 0.1s. The laser rangefinder reads the real-time height h(t) of the filament bundle and calculates the height deviation e(t) = H0-h(t), where H0 is the initial height when the bundle is full. Anti-interference measures (dead-zone control and integral separation) are implemented to prevent frequent cylinder movements caused by minor sensor fluctuations or mechanical vibrations. A dead-zone control mechanism is introduced into the system. The dead-zone threshold is set to 3mm. When |e(t)| < 3mm, the system is considered to be in a stable range, maintaining the current pressure output without PID adjustment. When |e(t)| ≥ 3mm, the PID adjustment algorithm is activated. Simultaneously, to prevent "integral saturation" (i.e., overshoot due to error accumulation) in the early stages of the cylinder's large stroke, when the deviation |e(t)| exceeds the set value (50mm), the integral term Ik is forced to 0, and only PD control is used. When the deviation enters a smaller range, the integral action is automatically restored. Because traditional PID parameters are fixed, they cannot simultaneously achieve both "rapid response" during tow bundle replacement and "high-precision voltage regulation" during normal production. Therefore, fuzzy logic is used to modify the PID parameters online, adjusting the input variables e(t) and... e(t) is divided into 7 fuzzy subsets: {NB (negative large), NM (negative medium), NS (negative small), ZO (zero), PS (positive small), PM (positive medium), and PB (positive large)}, and the following three fuzzy inference rules are adopted: Adjustment of the proportional coefficient Kp: When the deviation |e(t)| is large (such as PB, NB), the system needs to respond quickly, and the fuzzy rule output should be large. Kp; When the deviation is small (e.g., ZO, NS), in order to reduce overshoot, Kp should be appropriately reduced, but it needs to be increased again when the deviation is extremely small to enhance the "stiffness" of the system. Adjustment of the integral coefficient Ki: When the deviation is large, Ki takes a negative value or zero (NB / NM) to prevent overshoot by weakening the integral action; when the deviation is small (steady state). Ki is set to a positive value (PB / PM), and the steady-state error is eliminated by using strong integral action to ensure pressure accuracy; Adjustment of the differential coefficient Kd: When the rate of change of deviation is large, increase it. Kd provides a damping braking effect; Finally, the centroid method is used to convert the fuzzy output into precise parameter correction values. Kp, Ki、 Kd is added to the reference parameters, while ensuring that the cylinder output pressure is within a safe range. Output limiting and execution are performed to control the final control quantity u(k) within 0.2 MPa - 0.8 MPa.

[0021] After adopting the above control method, the device can overcome the frictional interference of the cylinder. Testing showed that the steady-state pressure control accuracy of the system improved from ±0.1 MPa using the traditional method to ±0.02 MPa, and the overshoot decreased from 25% to less than 4%. In actual production, this method increased the pass rate of filter rod suction resistance from 75.67% to 85%, significantly reducing product quality fluctuations caused by excessive compaction in the bottom area of ​​the fiber bundle.

[0022] Understandably, the mathematical model of the relationship between cylinder pressure and yarn bundle height stored inside the controller is determined through process experiments. The basic principle is: the higher the yarn bundle height (when fully packed), the lower the required cylinder pressure; the lower the height (close to an empty bundle), the higher the required pressure. This curve is used for compensation to ensure that the opening and closing forces on the yarn bundle remain dynamically balanced throughout its use.

[0023] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0024] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A pre-opening device for a filter rod forming machine, comprising a support frame, a rubber roller, a steel roller mounted on the support frame, and a servo motor for driving the steel roller, characterized in that, Further comprising: A pressure regulating mechanism, the pressure regulating mechanism includes a rubber roller mounting plate and a cylinder, the rubber roller mounting plate is slidably connected to the support frame; the rubber roller is mounted on the rubber roller mounting plate; the cylinder is mounted on the support frame and its piston rod is connected to the rubber roller mounting plate to drive the rubber roller away from or close to the steel roller; A detection control system, the detection control system includes a laser rangefinder and a controller, the laser rangefinder is mounted on the support frame and is located directly above the conveying path of the tow package; the laser rangefinder is electrically connected to the controller, and the controller is electrically connected to the cylinder.

2. The pre-opening device for a filter rod forming machine according to claim 1, characterized in that, The top and bottom of the rubber roller mounting plate have slide rail grooves; the top inner wall and bottom inner wall of the side frame of the support frame are provided with slide rails, and the slide rail grooves are fitted and mounted on the slide rails to enable the rubber roller mounting plate to be slidably connected to the side frame.

3. A pre-opening device for a filter rod forming machine according to claim 1 or 2, characterized in that, Further comprising a connecting column, a connecting groove is formed on the front side of the rubber roller mounting plate, and the connecting column is nested in the connecting groove; the piston rod of the cylinder is connected to the connecting column.

4. The pre-opening device for a filter rod forming machine according to claim 3, characterized in that, The support frame includes two side frames, a front mounting plate and a steel roller mounting plate, the front mounting plate is fixedly connected to the two side frames on its two sides respectively; the cylinder is mounted on the front mounting plate and its piston rod penetrates through the front mounting plate and is threadedly connected to the connecting column; the steel roller mounting plate is fixed to the rear side of the side frame, and the end of the steel roller is mounted on the steel roller mounting plate through a bearing.

5. A control method using the pre-opening device of a filter rod forming machine as described in any one of claims 1-4, characterized in that, Including the following steps: 1) Height sensing: The laser rangefinder monitors the current height h(t) of the tow package in real time at a preset sampling period T and transmits the data to the controller; 2) Deviation Calculation: The controller, based on the preset initial height H0 of the tow bundle, calculates the current height deviation e(t) = H0 - h(t) and the deviation change rate. e(t); 3) Strategy determination and parameter self-tuning: The controller adopts a fuzzy adaptive PID algorithm, using the height deviation e(t) and the rate of change of deviation as the parameters. Using e(t) as the input variable, the correction amount of the PID parameters is output in real time through fuzzy inference. Kp, Kihe Kd, and update the current proportional coefficient Kp, integral coefficient Ki, and differential coefficient Kd; 4) Pressure value calculation: The controller calculates the control increment according to the updated PID parameters and superimposes the feedforward compensation value based on the height deviation to obtain the target pressure control signal u(t); 5) Execution and feedback: The controller outputs a control signal to drive the cylinder, so that the rubber roller presses against the tow with the target pressure, and the actual pressure response of the cylinder is used as feedback to participate in the closed-loop regulation.

6. The control method according to claim 5, characterized in that, In the deviation calculation, a preset adjustment dead zone threshold Emax is set; when the calculated height deviation |e(t)| < Emax, the controller keeps the pressure output of the previous cycle unchanged; when |e(t)| ≥ Emax, the subsequent PID operation and pressure regulation are performed.

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