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CN-121992541-A - Fixed-length doffing intelligent positioning control method of rotor spinning doffing trolley

CN121992541ACN 121992541 ACN121992541 ACN 121992541ACN-121992541-A

Abstract

The invention belongs to the technical field of automatic control of textile machinery, and particularly relates to an intelligent positioning control method for fixed-length doffing of a rotor spinning doffing trolley, which dynamically triggers doffing instructions based on accumulated winding length of each spindle position, and combines an improved nearest neighbor path optimization algorithm and a two-section type interrupt driving accurate positioning mechanism to realize sub-millimeter stopping and full-automatic mechanical doffing of full-bobbin spindle positions according to the shortest unidirectional path; meanwhile, the method is characterized in that the upper monitoring subsystem is used for collecting encoder data in real time, the doffing control programmable logic controller is used for dynamically planning a cruising path, and the sensing mechanism is used for triggering deceleration braking in double edges, so that intelligent doffing operation with high precision, high efficiency and low interference risk is ensured. The invention solves the problems of large yarn length deviation, redundant path and insufficient positioning precision caused by the synchronous doffing of the existing whole machine.

Inventors

  • CHENG ZHIFANG
  • KOU XIAOFENG
  • WANG KAIJIE

Assignees

  • 经纬智能纺织机械有限公司

Dates

Publication Date
20260508
Application Date
20260119

Claims (10)

  1. 1. The fixed-length doffing intelligent positioning control method of the rotor spinning doffing trolley is characterized by being executed by a fixed-length doffing intelligent positioning control system, wherein the fixed-length doffing intelligent positioning control system comprises an upper monitoring subsystem, a doffing control programmable logic controller, the doffing trolley, a sensing mechanism and an executing mechanism, wherein the sensing mechanism and the executing mechanism are arranged on a doffing trolley body, and the method comprises the following steps: Firstly, an upper monitoring subsystem collects pulse signals output by spindle rotary encoders in real time, accumulates and converts the pulse signals into accumulated winding length, and when the accumulated winding length of any spindle reaches or exceeds a preset target fixed length threshold value, a doffing trigger instruction containing the spindle number is generated and sent to a doffing control programmable logic controller; secondly, after receiving one or more doffing trigger instructions, a doffing control programmable logic controller adopts a path optimization algorithm module to analyze physical position coordinates of corresponding target spindle positions, takes the current position of a doffing trolley as a starting node, dynamically constructs a shortest loop-free cruising path covering all the target spindle positions to be processed, and forcibly executes unidirectional travelling constraint in a path planning process, wherein the path optimization algorithm module adopts an improved nearest neighbor heuristic search strategy to dynamically construct the shortest loop-free cruising path covering all the target spindle positions to be processed; Furthermore, the doffing trolley sequentially moves to each target spindle position along the shortest loop-free cruising path, and before approaching each target spindle position, the two-section accurate positioning and stopping of the doffing trolley are realized through the interrupt response management unit, specifically: the sensing mechanism arranged on the trolley is matched with the metal detection target fixed on the main frame, two interrupt signals of the rising edge and the falling edge are captured, and a first-stage deceleration command and an emergency braking command are triggered respectively, so that two-stage accurate positioning and stopping of the doffing trolley are realized; then, after stopping, starting an executing mechanism to sequentially execute the actions of adsorbing, pushing out and moving out the old yarn cylinder and loading the new empty cylinder to finish single spindle doffing operation; And finally, repeating the moving, positioning and single spindle doffing operation processes until all the target spindle positions to be processed are doffed, and then returning to the waiting machine position.
  2. 2. The intelligent positioning control method for fixed-length doffing of a rotor spinning doffing trolley according to claim 1, wherein the conversion of the accumulated winding length of each spindle position is based on the following formula: in the formula, For the cumulative winding length of the ith spindle position, The accumulated pulse number of the ith spindle position is the accumulated pulse number, p is the theoretical winding length corresponding to a single pulse, the unit is mm, and k is the system calibration coefficient for compensating the winding error caused by yarn tension fluctuation and spindle disc abrasion.
  3. 3. The method for intelligently positioning and controlling fixed-length doffing of rotor spinning doffing trolley according to claim 1, wherein the improved nearest neighbor heuristic search strategy introduces direction weight factors when calculating the distance between nodes When the candidate target spindle position is positioned behind the current doffing trolley position, the effective distance is amplified to be the actual distance Multiple to ensure that the generated cruise path satisfies a one-way travel constraint, where >10。
  4. 4. The fixed-length doffing intelligent positioning control method of the rotor spinning doffing trolley according to claim 1, wherein the sensing mechanism is a proximity sensor array, the proximity sensor array is a plurality of high-frequency response type inductive proximity switches which are linearly arranged along the travelling direction of the trolley, each spindle bit is correspondingly provided with a metal detection target with a width covering an effective induction zone of the proximity sensor, the induction surface of the proximity sensor is parallel to the surface of the metal target, and the vertical interval is 3 mm.
  5. 5. The fixed-length doffing intelligent positioning control method of the rotor spinning doffing trolley according to claim 4 is characterized in that two-section accurate positioning stopping specifically comprises the steps that when a first proximity sensor enters a metal target sensing range and outputs a rising edge signal, a servo driving motor is switched to a low-speed operation mode, the speed is reduced to 0.05 m/s, the output torque is limited to 30% of a rated value, and when the sensor completely passes over the rear edge of the metal target and outputs a falling edge signal, the servo driving motor enters a zero-speed holding state and activates an electromagnetic band-type brake device to implement mechanical locking.
  6. 6. The fixed-length doffing intelligent positioning control method of the rotor spinning doffing trolley according to claim 1 is characterized in that an actuating mechanism is a mechanical actuating arm assembly, the mechanical actuating arm assembly comprises a vacuum chuck mechanism, a cylinder pushing cylinder, a new cylinder supplying slideway and a return spring mechanism, and the action sequence of the mechanical actuating arm assembly is that the vacuum chuck mechanism firstly descends to the top of an old yarn cylinder to establish negative pressure adsorption, the cylinder pushing cylinder synchronously stretches out to push the old yarn cylinder out of a spindle disc horizontally, then the vacuum chuck mechanism ascends and transversely moves out of a working area, the old yarn cylinder falls into a lower conveying belt, the new cylinder supplying slideway releases an empty cylinder under the action of gravity to enable the empty cylinder to slide into a spindle disc positioning groove, and finally, the mechanical actuating arm is wholly reset to an initial posture to prepare for executing a doffing task of a next target spindle position; The action sequence of the mechanical execution arm assembly is controlled by a pneumatic electromagnetic valve group, the action interval time of each cylinder is set to be a fixed value of 200 ms, the negative pressure start-stop and descending actions of the vacuum chuck mechanism are strictly synchronous, a photoelectric correlation sensor is arranged at the bottom of the new cylinder supply slideway and used for detecting the in-place state of the empty cylinder, and if a shielding signal is not detected within a preset time, the current doffing process is suspended and an alarm is triggered.
  7. 7. The method for intelligently positioning and controlling fixed-length doffing of a rotor spinning doffing trolley according to claim 1, wherein a task queue buffer area is arranged in a doffing control programmable logic controller and is used for temporarily storing a concurrent doffing trigger instruction, and executing a path optimization process again after receiving a new instruction set or finishing a spindle position at the end of a current path each time, so that a newly added target spindle position is brought into a next cruising period.
  8. 8. The fixed length doffing intelligent positioning control method of the rotor spinning doffing trolley according to claim 1, wherein the upper monitoring subsystem and the doffing control programmable logic controller are communicated through an industrial Ethernet, a time stamp synchronization mechanism is adopted, and the end-to-end transmission delay of a doffing trigger instruction is not more than 10 ms.
  9. 9. The intelligent positioning control method for fixed-length doffing of a rotor spinning doffing trolley according to claim 1, wherein the servo driving motor is provided with an encoder with resolution not lower than hundred thousand pulses per revolution, the position control resolution of the system in the track direction reaches 10 micrometers after the transmission of a speed reducer, and the repeated positioning precision is better than +/-0.1 mm.
  10. 10. The fixed-length doffing intelligent positioning control method of the rotor spinning doffing trolley according to claim 1 is characterized in that a laser ranging sensor is additionally arranged in front of a doffing trolley traveling path, a track area is scanned in real time, when unexpected obstacles are detected, a path optimization algorithm temporarily marks affected spindle positions as unreachable, the shortest cruising path is recalculated in the remaining reachable spindle positions, and the obstacle marks are automatically cleared after the task is completed.

Description

Fixed-length doffing intelligent positioning control method of rotor spinning doffing trolley Technical Field The invention belongs to the technical field of automatic control of textile machinery, and particularly relates to an intelligent positioning control method for fixed-length doffing of a rotor spinning doffing trolley. Background Rotor spinning is used as an important technical branch in the modern short fiber spinning process, and is widely applied to the fields of cotton spinning, chemical fiber and blending due to the advantages of high yield, high efficiency, strong adaptability to raw materials and the like. In the continuous production process of the rotor spinning machine, a doffing link is used as a key node for connecting spinning and subsequent processes, and the automation level and the control precision of the doffing link are directly related to the running efficiency of the whole machine, the consistency of yarn forming, the stability of subsequent processes such as spooling, doubling and the like. Along with the accelerated evolution of the textile industry in the intelligent and flexible directions, higher requirements are put forward on the precision, timeliness and system coordination capability of doffing operation, and the traditional doffing mode which depends on fixed beat and mechanical sequential execution is difficult to meet the current comprehensive targets of high quality, low loss and less humanized production. At present, a main rotor spinning device generally adopts a whole machine synchronous doffing strategy, namely, a doffing trolley traverses all spindle positions along a preset track in sequence, and no matter whether each yarn cylinder reaches a full cylinder state or not, doffing actions are executed according to a unified time sequence. The core structure of the yarn doffer comprises a track guiding mechanism, a pneumatic or electric executing unit and a time or position trigger-based sequence controller, and the periodic doffing task can be completed without complex sensing feedback. The scheme effectively simplifies the logic of a control system under the background that the automation degree of early equipment is limited and the production rhythm is relatively loose, and ensures the basic operation reliability through a standardized operation flow. However, such a "one-cut" doffing mechanism essentially ignores the actual roll length variability of each spindle due to material fluctuations, tension differences, broken ends, and the like, resulting in significant deviations in the yarn length of the resultant package. The inconsistent length not only easily causes the problems of tension mutation, frequent broken yarn and the like in the subsequent unwinding processing, but also can cause unbalance of the fixed-length proportion of the whole batch of yarns, and seriously affects the process stability and the quality of finished products in the weaving or knitting links. In addition, with the sustainable development of related technologies and the more stringent requirements of application scenes on performance indexes, the synchronous doffing strategy of the whole machine has some inherent characteristics in principle, so that the synchronous doffing strategy gradually shows limitations in coping with new challenges. The method is based on the fact that the whole machine doffing mode forcibly binds doffing trigger conditions with physical position traversal, and dynamic association between doffing behaviors and actual spinning states is broken. Furthermore, the mode lacks intelligent scheduling capability in path planning, even if only a few spindle positions reach a full cylinder, the doffing trolley still needs to complete full-stroke inspection, so that a large amount of invalid movement and time waste are caused, and meanwhile, the positioning mechanism of the doffing trolley depends on mechanical limit or rough feedback of a position encoder, so that sub-millimeter parking precision is difficult to realize in a high-speed running state. When the trolley approaches to the target spindle position, if the deceleration response is delayed or the braking is overshot, the trolley is very easy to interfere with a main machine structure when mechanical actions such as overturning, grabbing and the like are executed, the clamping stagnation of the yarn drum is caused by light weight, the positioning failure is caused by heavy weight, the damage of a transmission part is caused, and even the whole machine is stopped. Accordingly, to avoid such risks, operators often need to intervene to perform manual reset or parameter fine adjustment, which not only counteracts efficiency gains caused by automation, but also increases the probability of human misoperation in an intangible way. In addition, due to the lack of overall optimization of the multi-target doffing task, when a plurality of spindle positions are full of cylinders at the same time, the existing system ca