CN-121973451-A - Parameter optimization control system for continuous fiber additive manufacturing process

CN121973451ACN 121973451 ACN121973451 ACN 121973451ACN-121973451-A

Abstract

The invention relates to the technical field of additive manufacturing, in particular to a parameter optimization control system for a continuous fiber additive manufacturing process, which is used for extracting curvature and curvature change rate along a printing path, constructing a continuous fine tuning function of printing speed, fiber tension and extrusion multiplying power relative to arc length, taking fiber strain energy mutation and resin accumulation volume deviation minimization in a transition zone as targets, obtaining an optimal speed, tension and extrusion multiplying power curve through offline nested optimization, discretizing the curve into increment instructions according to a variable speed section, embedding a printing code, acquiring actual tension and accumulation width in real time in execution, and carrying out compensation correction based on a main deviation dynamic adjustment step length factor.

Inventors

QIU GUODONG

Assignees

万源市拾木源科技有限公司

Dates

Publication Date: 20260505
Application Date: 20260407

Claims (8)

1. A continuous fiber additive manufacturing process parameter optimization control system, comprising: the path curvature and change rate extraction module is used for carrying out discrete sampling along the arc length direction of the path to be printed, calculating the path curvature and the first derivative of each sampling point, and obtaining a curvature curve and a curvature change rate curve; The continuous fine-tuning function construction module is used for constructing continuous fine-tuning functions of the printing speed, the fiber tension and the extrusion multiplying power respectively related to the arc length by taking a curvature curve and a curvature change rate curve as independent variables, so that the dispatching function automatically returns to a straight channel region baseline value when the curvature approaches zero, smoothly transits to a curve region set value when the curvature is increased, and pre-deceleration and pre-tension before a curve are realized according to the positive and negative curvature change rates; the off-line multi-objective constraint optimization module takes a scheduling function as a decision variable, takes fiber strain energy mutation minimization and resin accumulation volume deviation minimization in a transition zone as combined optimization targets, solves constraint optimization problems off-line in a feasible domain of printing speed, fiber tension and extrusion multiplying power, and obtains an optimal speed curve, a optimal tension curve and an optimal extrusion multiplying power curve; the discretization instruction generation and embedding module discretizes a speed curve, a tension curve and an extrusion multiplying power curve according to a preset sampling period, sequentially converts the discretization instruction into continuous parameter control instructions distributed along the arc length, and embeds the continuous parameter control instructions into a printing motion code; And the real-time deviation compensation and correction module is used for collecting the actual fiber tension and the resin accumulation width in real time in the process of executing the printing motion code, comparing the actual fiber tension with expected values of a speed curve, a tension curve and an extrusion multiplying power curve one by one, carrying out small-amplitude compensation and correction on a current control instruction when the deviation exceeds a threshold value, and taking the corrected instruction as a control reference of a subsequent arc length position.
2. The optimization control system of parameters of a continuous fiber additive manufacturing process according to claim 1, wherein the calculating the path curvature and the first derivative thereof of each sampling point to obtain a curvature curve and a curvature change rate curve specifically comprises: dividing a path to be printed into an equal arc length section and a self-adaptive encryption section according to a curvature change rate threshold value of the path, adopting fixed large-step sampling in the equal arc length section, and adopting variable-step sampling which is reduced along with the increase of the curvature change rate in the self-adaptive encryption section; For each sampling point, taking the front and rear two adjacent sampling points to form a three-point circle, and calculating the reciprocal of the radius of the three-point circle as the path curvature of the corresponding sampling point; seven-point secondary smooth filtering is carried out on the obtained curvature sequence to obtain a curvature curve, and center difference is carried out on the curvature curve to obtain a curvature change rate curve.
3. The continuous fiber additive manufacturing process parameter optimization control system of claim 1 wherein the continuous fine tuning function is constructed by: numerical integration is carried out on the curvature change rate curve to obtain curvature change total quantity, and the curvature change total quantity is mapped to a negative interval and a positive interval through an arctangent function to obtain a preset direction factor; performing third power operation on the ratio of each curvature value on the curvature curve to a preset curvature threshold value to obtain a preset amplitude factor; setting the printing speed as a weighted sum of a straight road zone baseline value and a curve zone set value, wherein the weight is the product of a preset direction factor and a preset amplitude factor, respectively carrying out weighted summation on the fiber tension and the extrusion multiplying power according to the same weight rule, so that the curvature change rate is positive to realize pre-deceleration and pre-increase tension, and the curvature change rate is negative to realize slow acceleration and slow deceleration tension.
4. The optimization control system of parameters of a continuous fiber additive manufacturing process according to claim 1, wherein the obtaining of the optimal speed profile, tension profile and extrusion multiplying power profile comprises: the transition region is discretized into a plurality of subintervals, the values of the dispatching function at two end points are used as design variables in each subinterval, and the fiber strain energy mutation value and the resin accumulation volume deviation value are calculated respectively; Adopting an inner layer and outer layer nested optimizing mode, gradually reducing the feasible region of the printing speed by using a section elimination method with halving step length in the inner layer, and synchronously searching the optimal combination of the fiber tension and the extrusion multiplying power by using a golden section method in the outer layer; Substituting the printing speed, the fiber tension and the extrusion multiplying power obtained by optimizing each time into a combined optimization target, stopping iteration and outputting a current speed curve, a current tension curve and a current extrusion multiplying power curve when the relative variation of the objective function values of two continuous iterations is smaller than a preset convergence threshold.
5. The optimized continuous fiber additive manufacturing process parameter control system of claim 4, wherein said outer layer searches for an optimal combination of fiber tension and extrusion magnification in a golden section method simultaneously, comprising: Respectively setting an initial search interval of fiber tension and an initial search interval of extrusion multiplying power, and respectively taking two golden section points in the two intervals to generate four two-dimensional candidate points in a combined way; calculating a joint optimization target value corresponding to each candidate point, eliminating a subinterval where the candidate point with the maximum target value is located, and forming a new two-dimensional search interval by the areas where the three remaining candidate points are located; Repeating the first step and the second step until the length of the fiber tension interval and the length of the extrusion multiplying power interval are smaller than respective preset precision thresholds, and taking the middle point in the final interval as the optimal fiber tension and the optimal extrusion multiplying power.
6. The optimized control system for parameters of a continuous fiber additive manufacturing process according to claim 1, wherein said sequential conversion into continuous parameter control instructions distributed along the arc length comprises: dividing the arc length to be printed into a plurality of variable speed sections according to a curvature change rate curve, adopting a first sampling period in the section with a large curvature change rate absolute value, and adopting a second sampling period in the section with a small curvature change rate absolute value, wherein the first sampling period is smaller than the second sampling period; at each sampling moment, subtracting the speed value, the tension value and the extrusion multiplying power value of the current sampling point from the corresponding values of the previous sampling point respectively to obtain a speed increment, a tension increment and an extrusion multiplying power increment; And after the speed increment, the tension increment and the extrusion multiplying power increment are arranged according to a fixed sequence, sequentially writing the speed increment, the tension increment and the extrusion multiplying power increment into a parameter expansion field after a current line motion instruction in a printing motion code.
7. The optimization control system of parameters of a continuous fiber additive manufacturing process according to claim 1, wherein the compensation correction process is as follows: dividing the difference between the real fiber tension acquired in real time and the expected tension by the expected tension to obtain tension relative deviation, and dividing the difference between the real value of the resin stacking width and the expected width by the expected width to obtain width relative deviation; Respectively comparing the absolute value of the tension relative deviation with the absolute value of the width relative deviation, if the absolute value of the tension relative deviation is larger than or equal to the absolute value of the width relative deviation, taking the tension relative deviation as a main deviation, otherwise taking the width relative deviation as the main deviation, determining a compensation direction according to the positive and negative signs of the main deviation when the absolute value of the main deviation exceeds a preset threshold value, and multiplying the absolute value of the main deviation by a fixed step factor to obtain a compensation step; And synchronously adjusting the current printing speed command, the fiber tension command and the extrusion multiplying power command according to the compensation direction and the compensation step length, taking the adjusted command group as a control reference of the subsequent arc length position, and simultaneously accumulating the current main deviation value into a deviation history record to adjust the fixed step length factor of the next step.
8. The optimization control system of parameters of a continuous fiber additive manufacturing process of claim 7 wherein the fixed step factor is calculated by: storing the latest five main deviation values in a memory to form a deviation sliding window, and moving out the earliest primary deviation value in the window and moving in the new value after each new main deviation value is obtained; calculating the sum of absolute values of all main deviation values in the sliding window, and dividing the sum by five to obtain average deviation amplitude; Dividing the preset reference step size factor by the average deviation amplitude to obtain a preliminary adjustment value, taking a minimum step size limit value if the preliminary adjustment value is smaller than the minimum step size limit value, taking a maximum step size limit value if the preliminary adjustment value is larger than the maximum step size limit value, and taking a final value as a fixed step size factor used in the next compensation correction.

Description

Parameter optimization control system for continuous fiber additive manufacturing process Technical Field The invention relates to the technical field of additive manufacturing, in particular to a parameter optimization control system for a continuous fiber additive manufacturing process. Background The continuous fiber additive manufacturing is an advanced composite material molding technology for synchronously extruding and depositing a continuous fiber reinforcement and a thermoplastic resin matrix, has the advantages of excellent mechanical property, strong structural designability and the like, and is widely applied to the fields of aerospace, automobile weight reduction, unmanned aerial vehicle structural members and the like. In the printing process, the matching of the printing speed, the fiber tension, the extrusion multiplying power and other technological parameters directly influence the spreading form, the resin infiltration quality and the interlayer bonding strength of the fiber. In the continuous fiber additive manufacturing process, how to eliminate coupling interference between fiber strain energy mutation and resin accumulation volume deviation caused by continuous change of path curvature in a curve transition zone, and realize continuous micro-synchronous scheduling of printing speed, fiber tension and extrusion multiplying power along the arc length direction, thereby inhibiting fiber wrinkles and resin tumor defects which cannot be avoided in the traditional zoning parameter switching mode. Disclosure of Invention The invention aims to provide a continuous fiber additive manufacturing process parameter optimization control system, so as to solve the problems in the background. The aim of the invention can be achieved by the following technical scheme: a continuous fiber additive manufacturing process parameter optimization control system, comprising: the path curvature and change rate extraction module is used for carrying out discrete sampling along the arc length direction of the path to be printed, calculating the path curvature and the first derivative of each sampling point, and obtaining a curvature curve and a curvature change rate curve; The continuous fine-tuning function construction module is used for constructing continuous fine-tuning functions of the printing speed, the fiber tension and the extrusion multiplying power respectively related to the arc length by taking a curvature curve and a curvature change rate curve as independent variables, so that the dispatching function automatically returns to a straight channel region baseline value when the curvature approaches zero, smoothly transits to a curve region set value when the curvature is increased, and pre-deceleration and pre-tension before a curve are realized according to the positive and negative curvature change rates; the off-line multi-objective constraint optimization module takes a scheduling function as a decision variable, takes fiber strain energy mutation minimization and resin accumulation volume deviation minimization in a transition zone as combined optimization targets, solves constraint optimization problems off-line in a feasible domain of printing speed, fiber tension and extrusion multiplying power, and obtains an optimal speed curve, a optimal tension curve and an optimal extrusion multiplying power curve; the discretization instruction generation and embedding module discretizes a speed curve, a tension curve and an extrusion multiplying power curve according to a preset sampling period, sequentially converts the discretization instruction into continuous parameter control instructions distributed along the arc length, and embeds the continuous parameter control instructions into a printing motion code; And the real-time deviation compensation and correction module is used for collecting the actual fiber tension and the resin accumulation width in real time in the process of executing the printing motion code, comparing the actual fiber tension with expected values of a speed curve, a tension curve and an extrusion multiplying power curve one by one, carrying out small-amplitude compensation and correction on a current control instruction when the deviation exceeds a threshold value, and taking the corrected instruction as a control reference of a subsequent arc length position. The method for calculating the curvature and the first derivative of the path of each sampling point to obtain a curvature curve and a curvature change rate curve comprises the following steps: dividing a path to be printed into an equal arc length section and a self-adaptive encryption section according to a curvature change rate threshold value of the path, adopting fixed large-step sampling in the equal arc length section, and adopting variable-step sampling which is reduced along with the increase of the curvature change rate in the self-adaptive encryption section; For each sampling point, taking the front and rea