u200bHow does the automatic fiber laser cutting machine operate?
The task of the focus control system of the fully automatic fiber laser cutting machine is to collect and control the distance between the laser focus and the workpiece in real time, so that it is always in a better cutting position to improve the cutting quality. Data exchange and coordination complete the entire metal cutting process. The distance between the laser focus and the workpiece is collected by the capacitive sensor, and transmitted to the main controller TMS320F28335 in digital form through the signal processing circuit; the main controller performs digital filtering on this distance signal and the most-multiplicative curve fitting , So as to obtain the corresponding relationship curve between the focus distance and the capacitance value; the main controller takes the focus distance and the change rate of the focus distance as input through the fuzzy PID algorithm, and outputs the control voltage to the driver interface circuit to drive the servo motor to move the laser focus and the workpiece The distance between the two is always better, thereby improving the cutting quality and efficiency; the machine tool motion card mainly realizes the motion trajectory planning on the XY plane, and the focus control system realizes the constant cutting distance in the Z direction. 0 port carries out the data exchange of the movement state to complete the whole metal cutting process in coordination.
Design of focus position detection module for automatic fiber laser cutting machine
Considering factors such as measurement range, measurement accuracy, and cost, the Pcap01 special capacitance detection integrated chip of German CAM company is selected to design The focus position detection module obtains the focus position in real time. The Pcap01 capacitance detection chip has a built-in DSP signal processing unit, which has excellent characteristics such as high precision and high speed. The detection frequency can be as high as 500kHz. The capacitance measurement result has 24-bit accuracy, and it has ultra-high temperature stability and ultra-low temperature drift. The distance value between the structural drawings of the focus position detection module is converted into a digital quantity, and it is transmitted to the main controller for data processing through the SPI communication method. It should be noted that the signal line between the two needs to be a twisted-pair shielded wire and a 1K matching resistance should be added between each group of differential signal lines, so as to eliminate the common mode interference of the differential signal transmission line and strengthen the distance to a certain extent. Stability of distance signal transmission
The main function of the main program of the automatic fiber laser cutting machine: system initialization setting, data calibration between focus position and capacitance value, and zero return operation. Each function is encapsulated into corresponding subroutines, which are initialization subroutine, data labeling subroutine and zero return subroutine.
Data standard stator program flow chart. In the data standard stator program, the capacitance is measured by the Pcap01 capacitance detection module at each measuring point of known distance and the median filter is performed, so that the measurement range is reasonably segmented Then, curve fitting is performed on each segment by the least square method to achieve the calibration between the focal distance and the capacitance value. It should be noted that when the material of the workpiece or the working environment changes, the focal distance-capacitance characteristic curve will also change accordingly. At this time, data calibration must be performed again.
There is also a 2ms timer interrupt in the main controller of the automatic fiber laser cutting machine, which contains 3 subroutines: focus position detection subroutine, focus position control subroutine and system and machine tool motion control card communication subroutine . The focus position detection subprogram realizes the reading of the capacitance value of the capacitance measurement unit by the main control DSP; the focus position control subprogram realizes the control voltage output of the main control DSP to the motor; the system and the machine tool motion control card communication subprogram receive the instruction signal corresponding to the command signal The different working states of the system determine the direction of the program in the focus position detection subroutine. 2ms timer interrupt subroutine flowchart.
Focus position detection subroutine
The function of the focus position detection subroutine is to realize the data communication between the main controller and the capacitance detection chip, and to obtain the capacitance between the cutting head and the workpiece The value of the focus distance determined by the data label stator program and the focus distance value corresponding to the analytical formula of the capacitance value fitting curve are used for the focus position control subroutine to call. The focus position detection subroutine flowchart.
Focus position control subroutine
The function of the focus position control subroutine is to read the focus distance feedback value received by the focus position detection subroutine and substitute the feedback value into the fuzzy PID control algorithm In order to obtain the required control voltage signal to the motor, the closed-loop control of the focus distance is realized. The flowchart of the focus position control subroutine is shown in Figure 11.
The full-cover automatic fiber laser cutting machine is generally designed in the form of an internal steel frame and an external sheet metal package. The structure is completed by connecting the integral steel frame with the bed, and then hanging the side sheet metal on the steel frame. The overall height of the steel frame is determined by the Z-axis movement stroke, and it is sufficient to not interfere when the stroke range is satisfied and the safety margin is reserved. The overall shape of the sheet metal, the left and right sides are determined by the movement stroke of the drag chain and the beam part, and a certain safety distance is reserved on the left and right sides. The dimensions can refer to related factors such as the control of transportation costs and sheet metal costs. After finishing the main steel frame, according to the local design element points and the shape color, the whole part will be divided into parts.