CN-122008411-A - Self-adaptive control method and system for printed concrete stirring process

CN122008411ACN 122008411 ACN122008411 ACN 122008411ACN-122008411-A

Abstract

The application provides a self-adaptive control method and a self-adaptive control system for a printed concrete stirring process, wherein the method comprises the steps of acquiring a visual image sequence of the surface of a material in a stirring bin in real time, monitoring the thermal spectrum evolution of the material and acquiring the instantaneous torque of a main shaft, acquiring visual uniformity, temperature change rate and linear mapping relation between the instantaneous torque of the main shaft and off-line yield stress from three original signals, S3, carrying out self-adaptive control on the printed concrete stirring process according to the visual uniformity, the temperature change rate and the instantaneous torque of the main shaft, and the self-adaptive control system comprises a monitoring module, a calculation center and a control unit.

Inventors

YUAN YONG
ZHANG JIAOLONG
YAO XUPENG
SHENG RUYI
ZHANG JINYUAN
LIU YIQI

Assignees

同济大学

Dates

Publication Date: 20260512
Application Date: 20260413

Claims (10)

1. A self-adaptive control method for a printing concrete stirring process is characterized by comprising the following steps: s1, acquiring a visual image sequence of the surface of a material in a stirring bin in real time, monitoring the thermal spectrum evolution of the material and acquiring the instantaneous torque of a main shaft; s2, performing feature extraction and physical mapping on the three original signals acquired in the S1 to obtain a linear mapping equation between visual uniformity, temperature change rate and main shaft instantaneous torque and offline yield stress; And S3, performing self-adaptive control on the printed concrete stirring process according to the visual uniformity, the temperature change rate and the main shaft instantaneous torque, wherein a visual uniformity threshold value is used as a basic constraint condition, the temperature change rate is used as a chemical arbitration signal in cooperation with the current stirring process stage, if the visual uniformity reaches 95% and the temperature change rate is in a high-level friction heat release zone, the dry stirring stage is judged to be completed, a command of adding water pre-doped with a water reducing agent is sent out, if the visual uniformity reaches more than 95% and the temperature change rate is in a low-level platform zone, the slow hydration state is judged, a quick-setting agent injection command is sent out, if the visual uniformity reaches more than 95%, the temperature change rate enters a stable hydration zone and the main shaft instantaneous torque reaches a target calibration zone, the target rheological window is judged to be reached, and a discharging command is sent out, and if the visual uniformity reaches more than 95%, the discharging command is returned to step S1.
2. The method for adaptively controlling a mixing process of printed concrete according to claim 1, wherein in step S1, three data sampling frequencies are strictly synchronized with 1Hz as a sampling frequency.
3. The method for adaptively controlling a mixing process of printed concrete according to claim 1, wherein in the step S2, the visual uniformity is obtained by extracting an ROI of a video frame captured by a camera, removing an interference area, converting a color image into a gray scale image, and calculating a standard deviation of a pixel gray scale histogram.
4. The method for adaptively controlling a mixing process of printed concrete according to claim 3, wherein said visual uniformity is a uniform uniformity The formula is as follows: ; In the formula, To test the maximum value of the visual texture index in the interval, As the final stable value of the visual texture index, Is a real-time visual texture index, wherein, 、 Fitting according to the test result of the real-time visual texture index.
5. The method for adaptively controlling the stirring process of printed concrete according to claim 1, wherein the temperature change rate is used for dynamically extracting the highest temperature of the surface of the material as a representative value, a linear least squares regression algorithm is used for fitting temperature data in a preset sliding window, and the slope of the temperature data is calculated.
6. The method for adaptively controlling a mixing process of printed concrete according to claim 5, wherein the rate of change of temperature is The formula of (2) is: ; In the formula, Is the temperature increment, which represents the difference between the real-time measured temperature and the ambient temperature, n is the number of data points in the window, Is all within the window The average value of the data points, As an average value of the time series, To at the same time Temperature increment at time.
7. The method for adaptively controlling a mixing process of printed concrete according to claim 1, wherein in step S3, the system evaluates a temperature change rate If the visual uniformity reaches more than 95%, the temperature change rate is more than 0.01K/s, the completion of the dry mixing stage is judged, a command of adding water of the pre-doped water reducing agent is sent out, if the visual uniformity reaches more than 95%, the temperature change rate is less than 0.001K/s, the special low thermal activity in the induction period is shown, the slow hydration state is judged, the one-time injection command of the accelerator is sent out, and if the visual uniformity reaches more than 95% and 0.001K/s is less than or equal to And (2) judging a rapid hydration state less than or equal to 0.01K/S, judging that the target rheological window is reached if the instantaneous torque of the main shaft reaches a target calibration interval at the moment, activating a discharging signal, and returning to the step (S1) if the instantaneous torque of the main shaft does not reach the target rheological window.
8. The method for adaptively controlling the stirring process of printed concrete according to claim 1, wherein: the step of determining a linear mapping equation between the spindle instantaneous torque and the off-line yield stress and a target calibration interval comprises the following steps: Acquiring a plurality of groups of spindle instantaneous torques at different moments in the concrete stirring process and synchronously sampling and measuring offline yield stress data; Establishing a linear mapping equation between the instantaneous torque of the main shaft and the off-line yield stress by using a linear regression algorithm; Substituting a theoretical minimum static yield stress threshold value required by the bottom material non-collapse into the linear mapping equation according to the static yield stress threshold value requirement of the 3D printing process on the bottom material non-collapse to reversely calculate a target main shaft torque threshold value, and determining the target calibration interval by combining a preset safety redundancy range.
9. A self-adaptive control system for a printing concrete stirring process is characterized by comprising the following components: the monitoring module is used for collecting the multi-mode original signals of vision, heat sensitivity and instantaneous torque of the main shaft in the stirring process in real time; the computing center is used for carrying out feature mapping on the original signal, running a staged logic gate fusion algorithm to identify a process stage and generating a decision instruction of feeding or discharging according to the real-time state of the material; And the control unit is used for receiving the decision instruction, driving the feeding execution mechanism or the discharging mechanism to act, and realizing closed-loop control of the stirring process.
10. The self-adaptive control system for the printed concrete mixing process according to claim 9, wherein the monitoring module comprises a 4K industrial camera arranged in the center of the top of the mixing bin, an infrared heat-sensitive sensor arranged in the mixing barrel and a dynamic torque sensor arranged on the mixing main shaft, and a sunshade umbrella is arranged on the top of the mixing bin to shield the top of the 4K industrial camera.

Description

Self-adaptive control method and system for printed concrete stirring process Technical Field The application relates to the technical fields of civil construction and automatic construction, in particular to a self-adaptive control method and a self-adaptive control system for a printed concrete stirring process. Background The 3D concrete printing technology is used as a novel additive manufacturing technology, and has great potential in the field of automatic construction of tunnel lining, building components and the like. Unlike traditional casting processes, 3D printed concrete requires extremely high rheological consistency of the material after stirring and discharging to meet the stringent requirements of pumpability, extrudability and stacking stability, which requires precise control of the fresh mix performance of 3D printed concrete, as minor fluctuations in homogeneity or rheology can cause pump pipe blockage, structural collapse or poor interlayer adhesion. Currently, the industry relies primarily on empirical, timed agitation or single mode sensing monitoring, such as machine vision, torque, temperature monitoring. Machine vision techniques are widely used to evaluate geometric uniformity of a material surface, but due to visible wavelength limitations, they cannot penetrate the material surface to sense internal bulk rheological evolution and hydration hardening. While the monitoring scheme based on the spindle power or dynamic torque can feed back the macroscopic resistance of the materials, the monitoring scheme is extremely easy to be influenced by the local material accumulation or mechanical load fluctuation in the stirring chamber, and the temperature rise caused by physical friction or the condensation caused by chemical heat release of the materials are difficult to distinguish. The temperature change of the interior or the surface of a material system in the stirring process can be monitored through the temperature, but single temperature monitoring can only reflect the total heat effect of the system, hydration heat release, mechanical friction heat generation and environmental heat conduction heat cannot be distinguished, and the temperature data are mostly distributed in a single point, so that the three-dimensional temperature field distribution in the stirring bin is difficult to truly reflect. The existence of a perceived "blind spot" between the surface uniformity and the deep rheological properties of these single-mode monitoring means results in the inability of the prior art to accurately capture the critical state of the transition of materials from "physical mixing" to "chemical reactions" and staged chemical reactions. Especially under the condition of fluctuation of ambient temperature or fine adjustment of raw material components, static formula execution often causes performance deviation among batches of printing materials, and construction accidents such as pipe blockage or collapse are caused. Therefore, how to build a multi-mode fusion monitoring system with physical interpretability, and to eliminate the perception blind spot by utilizing the physical signal complementation of different dimensions, and to realize the self-adaptive discrimination and dynamic control of the evolution stage of the whole stirring process, has become a key technical challenge for realizing unmanned construction and high-quality closed-loop production of concrete. Disclosure of Invention The application aims to provide a self-adaptive control method and a self-adaptive control system for a printed concrete stirring process, which aim to eliminate a single perceived blind spot by utilizing the physical compensation effect of a visual, thermosensitive and mechanical multisource sensing mode, and realize accurate identification and rheological closed-loop control of the evolution stage of the whole stirring process by establishing a physical-driven 'physical-chemical' heat-generating decoupling arbitration mechanism so as to ensure that discharged materials have high rheological consistency and batch stability. In order to achieve the above object, the present application provides the following technical solutions: the application provides a self-adaptive control method for a printed concrete stirring process, which comprises the following steps: s1, acquiring a visual image sequence of the surface of a material in a stirring bin in real time, monitoring the thermal spectrum evolution of the material and acquiring the instantaneous torque of a main shaft; s2, performing feature extraction and physical mapping on the three original signals acquired in the S1 to obtain a linear mapping equation between visual uniformity, temperature change rate and main shaft instantaneous torque and offline yield stress; And S3, performing self-adaptive control on the printed concrete stirring process according to the visual uniformity, the temperature change rate and the main shaft instantaneous torque,