CN-121995749-A - Medium plate fine impact force-displacement control method based on composite optical fiber sensor

CN121995749ACN 121995749 ACN121995749 ACN 121995749ACN-121995749-A

Abstract

The invention provides a medium plate fine impulse-displacement control method based on a composite optical fiber sensor. The method comprises the steps of collecting speed signals, displacement signals, temperature signals and strain signals of a die in a fine blanking process in real time through a composite optical fiber sensing module, calculating actual blanking force and eccentric moment acting on the die based on the strain signals, inputting the speed signals, the displacement signals, the temperature signals and the actual blanking force of the die as system state vectors into a prediction model based on an MPC algorithm, generating an expected blanking displacement command sequence by taking the weighted sum of the minimum blanking force deviation between the actual blanking force and a preset target blanking force, the energy consumption of the blanking process and the abrasion loss and the eccentric moment of the die as optimization targets, and driving a hydraulic cylinder array according to the expected blanking displacement command sequence to execute blanking control on a metal plate blank. The invention realizes the cooperative control of the blanking force and the blanking displacement of the metal plate blank, and improves the blanking control precision of the metal plate blank.

Inventors

QIN XUNPENG
YIN CHUNYANG
DONG KANG
GUO XIANGYU

Assignees

湖北隆中实验室

Dates

Publication Date: 20260508
Application Date: 20260106

Claims (8)

1. The medium plate fine impact force-displacement control method based on the composite optical fiber sensor is characterized by comprising the following steps of: Acquiring a speed signal, a displacement signal, a temperature signal and a strain signal of the die in real time through a composite optical fiber sensing module; calculating an actual blanking force and an eccentric moment acting on a die based on a real-time acquired strain signal of the die, wherein the die is used for blanking the metal plate blank; the speed signal, the displacement signal, the temperature signal and the actual blanking force of the die are used as system state vectors and are input into a prediction model based on an MPC algorithm; Generating a desired blanking displacement command sequence of the hydraulic cylinder array in a current control period by taking a weighted sum of a blanking force deviation between the minimum actual blanking force and a preset target blanking force, an energy consumption amount of a blanking process, a wear amount of the die and the eccentric moment as an optimization target, wherein the desired blanking displacement command sequence comprises desired blanking displacement commands corresponding to a plurality of preset time points in the future; And driving a hydraulic cylinder array according to the first expected displacement blanking command in the expected blanking displacement command sequence, and executing blanking control on the metal plate blank, wherein the hydraulic cylinder array comprises a plurality of hydraulic cylinders.
2. The composite fiber sensor-based medium plate fine impact force-displacement control method according to claim 1, further comprising, after the performing the blanking control on the metal plate blank according to the first one of the sequence of desired blanking displacement commands to drive the hydraulic cylinder array: comparing the actual blanking force calculated based on the strain signal with a predicted value of the prediction model to determine a blanking force error; and updating parameters of the prediction model based on the blanking force error to obtain a prediction model with optimized parameters, wherein the prediction model is used for controlling the blanking of the metal plate blank in a subsequent control period.
3. The composite fiber sensor-based medium plate fine impact force-displacement control method according to claim 1, wherein the driving the hydraulic cylinder array according to the first one of the sequence of desired blanking displacement commands to perform blanking control on the metal plate blank comprises: Inputting the first expected displacement blanking instruction to a PID controller, and acquiring a basic displacement error between the PID controller based on the first expected displacement blanking instruction and actual displacement feedback of each hydraulic cylinder; Compensating the basic displacement error to obtain a corrected displacement error; Generating a control signal according to the corrected displacement error; And adjusting the movement of the hydraulic cylinder array according to the control signal, and executing blanking control on the metal plate blank.
4. The composite fiber sensor-based medium plate fine impact-displacement control method according to claim 3, wherein the following is adopted Compensating for the base displacement error, comprising: determining a corresponding average displacement error for an ith hydraulic cylinder; determining a difference between the average displacement errors of the ith hydraulic cylinder and the jth hydraulic cylinder; Based on the difference value and the calibrated cross coupling gain, obtaining the cross coupling compensation quantity of the ith hydraulic cylinder; And compensating the basic displacement error based on the cross coupling compensation amount.
5. The composite fiber sensor-based medium plate fine impact force-displacement control method according to claim 1, wherein the strain signal includes a plurality of local strain signals, the calculating the actual blanking force and the eccentric moment acting on the die based on the strain signal of the die acquired in real time includes: Converting each local strain signal into a local force by a pre-calibrated coefficient; summing the local forces to obtain the actual blanking force; Calculating a relative imbalance indicator based on each of the localized forces; And determining the eccentric moment according to the relative unbalance index.
6. The composite fiber sensor-based medium plate fine impact-displacement control method according to claim 1, wherein the step of determining the preset target blanking force comprises: Measuring the measuring temperature of the die in real time; Calculating a temperature difference between the measured temperature and a reference temperature; obtaining a temperature compensation quantity according to the temperature difference value and a preset temperature sensitivity coefficient; and adding the temperature compensation quantity to a preset basic target blanking force to obtain the target blanking force.
7. The composite fiber sensor-based medium plate fine impulse-displacement control method according to claim 3, wherein the prediction model is a discrete state space model, and the expression of the discrete state space model is: x(t+1) = A·x(t) + B·u(t);y(t) = C·x(t); Wherein x (t) is a system state vector at time t, u (t) is a control signal of the hydraulic cylinder array at time t, y (t) is a system output vector comprising current actual blanking force and eccentric moment, A, B, C is a system matrix.
8. The composite fiber sensor-based medium plate fine impact-displacement control method according to claim 2, wherein updating parameters of the prediction model based on the blanking force error comprises: determining a parameter adjustment amount of the prediction model based on the blanking force error; And updating parameters of the prediction model by using the parameter adjustment quantity by adopting a recursive least square method or a gradient descent method.

Description

Medium plate fine impact force-displacement control method based on composite optical fiber sensor Technical Field The invention relates to the technical field of fine blanking control, in particular to a medium plate fine impact force-displacement control method based on a composite optical fiber sensor. Background The fine blanking of the metal plate blank is a key manufacturing process in the field of high-end equipment such as aerospace, automobile manufacturing and the like, and taking a medium plate as an example, the blanking of the medium plate has more severe requirements on the dimensional accuracy, the section quality and the burr control of parts, and typical indexes comprise that the dimensional tolerance is controlled within +/-0.01 mm, the section roughness Ra is less than 0.8 mu m, and the burr height is less than 0.02 mm. In the related art, the fine punching force-displacement control of the medium plate based on the composite optical fiber sensor generally adopts open-loop control of punching force-punching displacement or fixed parameter control, however, the control mode depends on a preset die gap or a single PID closed-loop control hydraulic cylinder pressure, and has slow response to material thickness fluctuation, temperature drift and die abrasion and insufficient control precision. The open loop control strategy of blanking force and blanking displacement depends on preset die gaps and process parameters, and cannot respond rapidly and adaptively to variable factors such as material thickness fluctuation, temperature drift and die abrasion in the blanking process, so that the control precision is insufficient, the accuracy of blanking control of a metal plate blank is reduced, and the machining precision and section quality of the metal plate blank are affected. Disclosure of Invention In view of the foregoing, it is necessary to provide a method for controlling fine impact force and displacement of a medium plate based on a composite optical fiber sensor, so as to solve the technical problem of low blanking control precision of a metal plate blank in the prior art. In order to solve the technical problems, in a first aspect, the present invention provides a method for controlling fine impact force-displacement of a medium plate based on a composite optical fiber sensor, comprising: Acquiring a speed signal, a displacement signal, a temperature signal and a strain signal of the die in real time through a composite optical fiber sensing module; calculating an actual blanking force and an eccentric moment acting on a die based on a real-time acquired strain signal of the die, wherein the die is used for blanking the metal plate blank; the speed signal, the displacement signal, the temperature signal and the actual blanking force of the die are used as system state vectors and are input into a prediction model based on an MPC algorithm; Generating a desired blanking displacement command sequence of the hydraulic cylinder array in a current control period by taking a weighted sum of a blanking force deviation between the minimum actual blanking force and a preset target blanking force, an energy consumption amount of a blanking process, a wear amount of the die and the eccentric moment as an optimization target, wherein the desired blanking displacement command sequence comprises desired blanking displacement commands corresponding to a plurality of preset time points in the future; And driving a hydraulic cylinder array according to the first expected displacement blanking command in the expected blanking displacement command sequence, and executing blanking control on the metal plate blank, wherein the hydraulic cylinder array comprises a plurality of hydraulic cylinders. In one possible implementation manner, after the hydraulic cylinder array is driven according to the first desired displacement blanking command in the desired blanking displacement command sequence, blanking control is performed on the sheet metal blank, the method further includes: comparing the actual blanking force calculated based on the strain signal with a predicted value of the prediction model to determine a blanking force error; and updating parameters of the prediction model based on the blanking force error to obtain a prediction model with optimized parameters, wherein the prediction model is used for controlling the blanking of the metal plate blank in a subsequent control period. In one possible implementation manner, the driving the hydraulic cylinder array according to the first desired displacement blanking command in the desired blanking displacement command sequence performs blanking control on the sheet metal blank, including: Inputting the first expected displacement blanking instruction to a PID controller, and acquiring a basic displacement error between the PID controller based on the first expected displacement blanking instruction and actual displacement feedback of each hydraulic cylinde