Laser cutting system and method self-adaptive to plate thickness

Abstract

The invention belongs to the field of laser cutting, and discloses a laser cutting system and method self-adaptive to plate thickness, and the laser cutting system comprises a cuboid mechanical platform, a monitoring system arranged at one end of the mechanical platform in the length direction, an optical system movably arranged in the width direction of the mechanical platform, and a control system arranged at the bottom of the mechanical platform; the optical system is connected with the mechanical platform through the transmission system to realize movement in three directions; the optical system comprises a laser tube parallel to the width direction of the mechanical platform, a reflecting mirror A and a reflecting mirror B which are arranged at one end of the laser tube and are oppositely arranged, a laser device arranged in the middle of the laser tube, and a reflecting mirror C arranged on the laser device; the reflector A, the reflector B and the reflector C are located at the same height; the control system is connected with the monitoring system, the optical system and the transmission system. According to the system, a cutting system and a control system are integrated, and real-time optimization of cutting parameters, precise cutting and whole-process automatic control are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of laser cutting, and in particular to a laser cutting system and method for adaptive plate thickness. Background Art

[0002] During the shipbuilding process, it is necessary to cut 1-20mm wooden samples for comparison to check whether the hull line is correct. However, during the cutting process, wooden boards of different thicknesses are easily heated unevenly due to unstable cutting height, too fast cutting speed, and too high cutting power, causing the cut wooden boards to carbonize, crack or warp. This will cause the cutting lines of the wooden boards to be blurred and unclear, affecting the cutting quality and accuracy. Traditional wooden board cutting usually requires the operator to have a high degree of experience, and usually requires manual adjustment of the cutting head height and cutting parameters to adapt to different board thicknesses. This manual adjustment process is not only time-consuming and labor-intensive, but also easily leads to unstable cutting quality and failure to meet cutting accuracy requirements and standards.

[0003] Therefore, it is necessary to provide a laser cutting system with adaptive plate thickness, which can achieve highly accurate positioning of the cutting head through an optimized PID algorithm, adjust the cutting parameters according to different plate thicknesses, realize fixed-focus cutting of different plate thicknesses, and improve cutting quality and production efficiency.

[0004] Chinese invention patent: Publication number is "CN118951397A", ​​and the name is "Tube laser cutting machine head height follow-up control system and method", which discloses a tube laser cutting machine head height follow-up control system and method, including an execution unit, a control unit and a drive unit, wherein the control unit is electrically connected to the execution unit and the drive unit respectively; the execution unit includes a laser rangefinder and a cutting machine head arranged in sequence along the rotation direction of the workpiece, wherein the laser rangefinder and the cutting machine head are arranged with the same diameter in the circumferential direction around the rotation center of the workpiece, and the laser rangefinder and the cutting machine head have a difference in the rotation path. This technical solution enables the laser rangefinder and the cutting machine head to have a distance difference in the rotation path, so that the laser rangefinder will interfere with the workpiece before the cutting machine head, that is, the laser rangefinder is used to continuously measure the distance between it and the workpiece and feed it back to the control unit, and the control unit can generate a workpiece model using these several measured distances. However, in this technical solution, the laser rangefinder requires a certain response time when measuring the distance, and cannot respond quickly to the optimal cutting height, and there is a certain error, which cannot meet the requirements of high-precision cutting. Summary of the invention

[0005] In order to solve the problem that the manual adjustment process in the above-mentioned prior art is not only time-consuming and labor-intensive, but also easily leads to unstable cutting quality and failure to meet cutting accuracy requirements and standards, the present invention proposes a laser cutting system and method for adaptive plate thickness. The laser cutting system can accurately detect the thickness of the plate, and optimizes the PID proportional control coefficient Kp by improving the PSO algorithm. The PID algorithm controls the drive motor to quickly respond to the positioning cutting head height, and intelligently adjusts the cutting parameters according to the detection results, thereby achieving precise cutting of different plate thicknesses, high production efficiency and high cutting quality.

[0006] The present invention is realized by the following technical scheme: it comprises a rectangular mechanical platform, a monitoring system arranged at one end of the mechanical platform in the length direction, an optical system movably arranged along the width direction of the mechanical platform, and a control system arranged at the bottom of the mechanical platform; the optical system is connected to the mechanical platform through a transmission system to realize movement in three directions; the optical system comprises a laser tube arranged parallel to the width direction of the mechanical platform, a reflector A and a reflector B arranged at one end of the laser tube and arranged oppositely, a laser device arranged in the middle of the laser tube, and a reflector C arranged on the laser device; the reflector A, the reflector B and the reflector C are at the same height; the control system is respectively connected to the monitoring system, the optical system and the transmission system.

[0007] As a further preference, the transmission system includes two movable guide rails arranged along the length direction of the mechanical platform and respectively arranged on both sides of the length direction of the mechanical platform, a first drive motor with an output end facing one of the movable guide rails and meshing with the gears arranged on the guide rails, an output end parallel to the width direction of the mechanical platform and facing the second drive motor in the mechanical platform, and a first movable lead screw arranged parallel to the width direction of the mechanical platform and fixedly connected to the output end of the second drive motor; the two ends of the optical system are respectively slidably connected to the two movable guide rails, the fixed end of the first drive motor is fixedly connected to the optical system, a slider is arranged at the corresponding position of the optical system, and the slider cooperates with the first movable lead screw; the transmission system also includes a second movable lead screw arranged along the height direction of the mechanical platform and one end of which cooperates with the slider on the optical system, and a third drive motor with an output end facing the mechanical platform and fixedly connected to the second movable lead screw, the laser device is fixedly connected to the fixed end of the third drive motor, and the control system is respectively connected to the first drive motor, the second drive motor and the third drive motor.

[0008] As a further preference, the monitoring system includes a visual sensor fixedly connected to the fixed end of the third drive motor and a high-definition camera arranged at one end of the mechanical platform, and the visual sensor and the high-definition camera are connected to the control system.

[0009] As a further preference, the monitoring system also includes pressure sensors arranged on the movable guide rail, the first movable lead screw and the second movable lead screw.

[0010] As a further preference, the sampling frequency of the visual sensor is 1 kHz to 10 kHz.

[0011] As a further preference, the mechanical platform is provided with a smoke exhaust system away from the monitoring system, and the smoke exhaust system includes a negative pressure fan arranged on one side of the mechanical platform, a smoke exhaust duct arranged inside the mechanical platform, and a drawer arranged at the bottom of the mechanical platform.

[0012] As a further preference, the optical system further comprises an adjustable mirror frame, and the reflector A, reflector B and reflector C are mounted on the adjustable mirror frame.

[0013] The present invention also provides a working method of the laser cutting system for adaptive plate thickness according to the present invention, which is characterized by comprising the following steps:

[0014] S1, placing the plate on the mechanical platform, moving the guide rail and the first drive motor to move the laser device to the initial cutting area;

[0015] S2, the high-definition camera of the monitoring system takes images and sends them to the control system. The visual sensor collects the height h of the laser device in real time. 激 , and sent to the control system;

[0016] S3. The processor in the control system processes the image to obtain the thickness H of the plate. 实际 ;

[0017] S4. The processor in the control system uses the improved PSO algorithm to calculate the K of the PID controller. p Optimize the parameters and use the optimized K p The K parameter of the PID controller i and K d Parameter synthesis output, to obtain the motor drive signal;

[0018] S5, the motor adjusts the height of the laser device according to the torque and speed of the motor driving signal;

[0019] S6, the laser device starts cutting, and the monitoring system monitors the thickness of the plate and the height of the laser device in real time, and repeats steps S2 to S5 until the cutting is completed.

[0020] As a further preference, the specific steps of step S4 are as follows:

[0021] S41: the thickness H of the plate obtained in step S3 实际, calculate the height error e, if |e|>0.1mm, execute step S42, otherwise terminate the optimization and proceed directly to cutting; the calculation formula of e is as follows:

[0022] e=h 激 -H 实际 -ε

[0023] In the formula, h 激 H is the height of the laser device (115); 实际 is the thickness of the plate; ε is the reserved height;

[0024] S42, using SINE chaotic mapping to initialize PID parameter K p , the formula is as follows:

[0025]

[0026] Where P 电 is the maximum output power of the motor; is the initial value of the PID controller parameters;

[0027] S43. Construct a fitness function according to the adjustment time, overshoot and penalty value. The formula is as follows:

[0028] f=α·ITAE+β·OS+γ·t s

[0029]

[0030] Where, f is the fitness value; ITAE is the penalty value; OS is the overshoot; t s is the adjustment time; α, β and γ are weight coefficients;

[0031] S44, improved dynamic adaptive inertia weight and acceleration factor adjustment K p ;

[0032] S441. Adjust the inertia weight w of the current iteration cycle according to the number of iterations. The formula is as follows:

[0033]

[0034] Where k is the current iteration number; k max is the maximum number of iterations;

[0035] S442, dynamically adjust the acceleration factors c1 and c2. When the number of iterations k is less than 30, c1 is 2.5 and c2 is 1.5; when the number of iterations k is greater than or equal to 30, c1 is 1.5 and c2 is 2.5;

[0036] S443. According to the height error e, the error change rate ec is obtained, ec=de / dt. If |ec|>0.5mm / s, the number of iterations k is reset to 1, and step S441 is executed; if |ec|<0.1mm / s, and the number of iterations k at this time is <30, the number of iterations k is reset to 30, and step S441 is executed;

[0037] S45. Update particle velocity position. The formula is as follows:

[0038]

[0039] Wherein, r1 and r2 are random numbers of (0, 1);

[0040] S46, introduce vertical and horizontal cross optimization mechanism to optimize K p parameter;

[0041] S461, perform a lateral cross operation on the particles after the speed and position are updated in step S45, the formula is as follows:

[0042]

[0043] S462, perform longitudinal crossover on the particles after the speed and position are updated in step S45, the formula is as follows:

[0044]

[0045] S463, perform the horizontal crossover of step S461 every ten iterations, and perform the vertical crossover of step S462 every five iterations when the individual optimum is not updated;

[0046] S47, when the number of iterations reaches the maximum number of iterations, or the fitness value f < 0.1, or the global optimal solution is not updated for 20 consecutive iterations, the iteration ends and the final K is output. p value; otherwise continue to iterate;

[0047] S48, according to the actual height h of the laser device collected by the visual sensor in step S2 激 , get the instantaneous error, the formula is as follows:

[0048] e′(t)=h 目标 -h 激 (t)

[0049] In the formula, h 目标 h is the height to which the laser device should move; 激 (t) is the real-time height of the laser device collected by the visual sensor;

[0050] S49, based on the instantaneous error obtained in step S48 and the final K obtained in step S47 p, and get the output proportional term P out , the formula is as follows:

[0051] P out =K P ·e′(t)

[0052] S410, according to the integral parameter K of the PID controller itself i and the differential parameter K d , and get the output integral term I out and the differential term D out , the formula is as follows:

[0053]

[0054] Where, T s is the sampling period, preferably 0.001 seconds; D filtered is the output differential term after suppressing high-frequency noise; s is the Laplace variable; δ is the time constant of the low-pass filter;

[0055] S411, output proportional term P obtained in step S49 out The integral term I of the output obtained in step S410 out , differential term D filtered , get the motor drive signal u(t), the formula is as follows:

[0056] u(t)=P out +I out +D filtered

[0057] S412, obtaining the voltage and current of the motor according to the motor drive signal u(t), thereby obtaining the output torque and speed of the motor, and the formula is as follows:

[0058]

[0059] Where τ is the torque; J is the moment of inertia; B is the damping coefficient.

[0060] As a further preference, the values ​​of the weight coefficients α, β and γ in step S43 are 0.6, 0.3 and 0.1 respectively.

[0061] Compared with the prior art, the present invention has the following beneficial effects:

[0062] 1. The present invention optimizes the dynamic adjustment parameters of the PSO algorithm through nonlinear inertia weight and segmented acceleration factor, realizing seamless switching between rapid response of thick plates and fine adjustment of thin plates. The robustness of the PSO algorithm is enhanced by cross-coupling of horizontal and vertical directions, avoiding local optimal traps.

[0063] 2. The present invention optimizes the proportional control coefficient Kp through the PSO-PID algorithm, which can quickly respond to the positioning and adjust the height of the laser head, significantly improving the cutting accuracy and efficiency.

[0064] 3. The system of the present invention integrates the cutting system, control system and smoke exhaust system, realizing real-time optimization of cutting parameters, precise cutting, full-process automatic control and intelligent smoke exhaust. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 It is a schematic diagram of the overall structure of the cutting system of the present invention.

[0066] Figure 2 It is a schematic diagram of the internal structure of the cutting system of the present invention.

[0067] Figure 3 It is a side view of the cutting system of the present invention.

[0068] Figure 4 It is a partial enlarged view of the cutting head structure of the present invention.

[0069] Figure 5 It is a flow chart of the cutting method of the present invention.

[0070] Indicated in the figure:

[0071] 100. Optical system; 101. Smoke exhaust system; 102. Control system; 103. Transmission system; 104. Monitoring system; 105. Mechanical platform; 106. Laser tube; 107. Reflector A; 108. Reflector B; 109. Reflector C; 110. Moving guide rail; 111. First drive motor; 112. Second drive motor; 113. First moving lead screw; 114. Visual sensor; 115. Laser device; 116. Second moving lead screw; 117. Third drive motor; 118. Negative pressure fan. DETAILED DESCRIPTION

[0072] Advantages and features of the present invention will be illustrated and explained by the following non-limiting description of preferred embodiments thereof, which are given by way of example only with reference to the accompanying drawings.

[0073] The invention designs a laser cutting system, comprising a laser cutting machine, which cuts wooden boards with different thicknesses according to the principle of laser cutting.

[0074] like Figures 1 to 4As shown, the present invention provides a self-adaptive plate thickness laser cutting system, comprising an optical system 100, a smoke exhaust system 101, a control system 102, a transmission system 103, a monitoring system 104 and a mechanical platform 105. The mechanical platform 105 is in a rectangular shape as a whole, the optical system 100 is movably arranged along the width direction of the mechanical platform 105, the smoke exhaust system 101 is arranged at one end of the mechanical platform 105 in the length direction, the monitoring system 104 is arranged at one end away from the smoke exhaust system 101, and the control system 102 is arranged at the bottom of the mechanical platform 105.

[0075] The transmission system 103 is connected to the optical system 100 and can move the optical system 100 along three axial directions: X, Y, and Z. The X-axis direction is the width direction of the mechanical platform 105, the Y-axis direction is the length direction of the mechanical platform 105, and the Z-axis direction is the height direction of the mechanical platform 105. The transmission system 103 includes a moving guide rail 110, a first drive motor 111, a second drive motor 112, a first moving lead screw 113, a second moving lead screw 116, and a third drive motor 117. The moving guide rail 110 is arranged along the length direction of the mechanical platform 105, and there are two of them, which are respectively arranged on both sides of the length direction of the mechanical platform 105, and the two ends of the optical system 100 are respectively slidably connected with the two moving guide rails 110. The output end of the first driving motor 111 faces the moving guide rail 110 on one side and meshes with the gear provided on the guide rail 110. The fixed end of the first driving motor 110 is connected to the optical system 100. The cooperation between the first driving motor 111 and the moving guide rail 110 can make the optical system 100 move along the Y axis, that is, move along the length direction of the mechanical platform 105. The output end of the second driving motor 112 is parallel to the width direction of the mechanical platform 105 and faces the inside of the mechanical platform 105. The first moving lead screw 113 is arranged parallel to the width direction of the mechanical platform 105 and is fixedly connected to the output end of the second driving motor 112. A slider is arranged at the corresponding position of the optical system 100, and the slider cooperates with the first moving lead screw 113. Through the cooperation of the slider, the first moving lead screw 113 and the second driving motor 112, the optical system 100 can move freely along the X axis, that is, move freely along the width direction of the mechanical platform 105.

[0076] like Figure 4As shown, the second movable lead screw 116 is arranged along the height direction of the mechanical platform 105, and one end cooperates with the slider on the optical system 100, and the other end is connected to the output end of the third drive motor 117. The output end of the third drive motor 117 faces the mechanical platform 105, and the laser device 115 and the visual sensor 114 are fixedly connected to the fixed end of the third drive motor 117. The laser device 115 and the visual sensor 114 are both vertically downward toward the mechanical platform 105. Through the cooperation of the slider, the second movable lead screw 116 and the third drive motor 117, the optical system 100 can be freely moved along the Z axis, that is, moved along the height direction of the mechanical platform 105, and specifically, the laser device 115 and the visual sensor 114 of the optical system 100 can be moved along the height direction of the mechanical platform 105.

[0077] The optical system 100 includes a laser tube 106, a reflector A107, a reflector B108, a reflector C109, a laser device 115 and an adjustable mirror frame. The laser tube 106 is arranged parallel to the width direction of the mechanical platform 105. The reflector A107 and the reflector B108 are arranged at the end of the laser tube 106 away from the first drive motor 111 and are arranged opposite to each other. The reflector C109 is arranged at the end of the laser device 115 away from the mechanical platform 105. The reflectors A107, B108 and C109 are at the same height. The reflectors A107, B108 and C109 are installed on the adjustable mirror frame, and the adjustable mirror frame ensures that the three reflectors are at the same height. The laser tube 106 emits a laser, and through the action of the three reflectors, the laser is reflected on the laser device 115, and the laser device 115 performs laser cutting in the cutting area. The laser tube 106 is provided with a laser and a laser power supply inside. The laser and the laser power supply are connected. After the laser power supply generates electrical energy, the laser emits laser.

[0078] The monitoring system 104 includes a visual sensor 114, a high-definition camera arranged at one end of the mechanical platform 105, and a monitoring device arranged on the movable guide rail 110, the first movable lead screw 113 and the second movable lead screw 116, which may be a pressure sensor, etc. The sampling frequency of the visual sensor 114 is generally 1kHz to 10kHz. The control system 102 is connected to the visual sensor 114 and the high-definition camera of the monitoring system 104, and is also connected to the laser tube 106 of the optical system 100. The control system 102 is connected to the first drive motor 111, the second drive motor 112 and the third drive motor 117. When the value detected by the monitoring device exceeds the set threshold, a signal is sent to the control system 102, and the control system 102 controls the corresponding motor to stop running to prevent system damage. The high-definition camera sends the captured image to the control system 102, and the processor inside the control system 102 identifies and judges the thickness and position of the plate and sends the judgment result to the PLC controller of the control system 102. The visual sensor 114 monitors the current height of the laser device 115 and sends it to the control system 102. The control system 102 uses the PLC controller to automatically drive the motor to perform PID fast response and position the laser device 115 for cutting.

[0079] The smoke exhaust system 101 includes a negative pressure fan 118 disposed on one side of the mechanical platform 105 and a smoke exhaust pipe disposed inside the mechanical platform 105. The smoke exhaust system 101 mainly utilizes the negative pressure adsorption of the fan to exhaust the cutting smoke. The smoke exhaust system 101 may also include a drawer disposed at the bottom of the mechanical platform 105, and the drawer is used to collect larger cutting waste. The mechanical platform 105 also includes a protective cover covering the laser tube 106, and the protective cover is made of stainless steel to protect the laser tube 106 from damage.

[0080] like Figure 5 As shown, the present invention also provides a working method of the laser cutting system suitable for the adaptive plate thickness of the present invention, comprising the following steps:

[0081] Step 1: Place the plate on the mechanical platform 105 , and move the guide rail 110 and the first drive motor 111 to move the laser device 115 to the initial cutting area.

[0082] Step 2: The high-definition camera of the monitoring system 104 captures an image and sends the image to the control system 102. The visual sensor 114 collects the height h of the laser device 115 in real time. 激 , and sent to the control system 102.

[0083] Step 3: The processor in the control system 102 processes the image to obtain the thickness H of the plate. 实际 .

[0084] Here, the steps of processing the image by the processor inside the control system 102 include preprocessing, Canny operator edge detection, etc., to obtain the thickness H of the plate. 实际 .

[0085] Step 4: The processor in the control system 102 uses an improved particle swarm optimization algorithm (PSO algorithm for short) to optimize the K of the PID controller. p Optimize the parameters and use the optimized K p The K parameter of the PID controller i and K d The parameters are synthesized and output to obtain the motor drive signal.

[0086] Step 41: The thickness H of the plate obtained in step 3 实际 , calculate the height error e, if

[0087] If |e|>0.1mm, execute step 42, otherwise terminate the optimization and proceed directly to cutting. The calculation formula of e is as follows:

[0088] e=h 激 -H 实际 -ε

[0089] In the formula, h 激 H is the height of the laser device 115 collected in real time by the visual sensor 114 in step 2; 实际 is the thickness of the plate obtained in step 3; ε is the reserved height. In the plate cutting process, different sizes of reserved heights need to be reserved for plates of different thicknesses. For example, for plates of 0-5 mm, the reserved height is 2 mm, for plates of 5-10 mm, the reserved height is 2.5 mm, and for plates of 10-20 mm, the reserved height is 4 mm. That is, the value of ε is related to H 实际 The value corresponds to, if H 实际 The value of is 0-5, then the value of ε is 2. If H 实际 The value of is 5-10, then the value of ε is 2.5. If H 实际 If the value of is 10-20, then the value of ε is 2.

[0090] In the laser cutting system, the K of the PID controller p (Proportional gain) directly affects the dynamic response speed and steady-state accuracy of the laser device 115. The original PSO algorithm uses random initialization K p , resulting in uneven distribution of particle swarm in parameter space, which may miss the global optimal solution. The present invention uses SINE chaotic mapping to generate the initial K p The specific steps are as follows:

[0091] Step 42: Initialize PID parameter K using SINE chaotic mapping p , the formula is as follows:

[0092]

[0093] Where P 电 is the maximum output power of the motor, unit: watt (w); are the initial values ​​of the PID controller parameters.

[0094] To prevent hardware damage, if the chaos map is initialized Greater than P 电 , then P 电 The value of Execute the subsequent loop.

[0095] This step uses the ergodicity and pseudo-randomness of the chaotic sequence to generate the chaotic value x n Linear mapping to K p The actual search range is [0, P 电 ]. With x0 equal to 0.5, the maximum output power of the motor is P 电 Taking 300 watts as an example, this step will generate a chaos value x n Linear mapping to K p The actual search range is [0, 300], generating a chaotic sequence {0.99, 0.02, 0.06, ...}, corresponding to K p The initial values ​​are 297, 6, 18, etc. This mechanism ensures global coverage and dynamic adaptability. p The values ​​are evenly distributed in the low, medium, and high gain ranges to avoid local aggregation. p =297 Suitable for thick plates (20mm) with fast response, K p =6 is suitable for thin plates (1mm) to suppress overshoot. When the control system 102 detects a sudden change in the thickness of the plate (for example, switching from 1mm to 20mm), the chaos initialization automatically generates a K that matches the current working condition. p Initial value, reduce manual intervention.

[0096] Step 43: Construct a fitness function according to the adjustment time, overshoot and penalty value. The formula is as follows:

[0097] f=α·ITAE+β·OS+γ·t s

[0098]

[0099] Wherein, f is the fitness value; ITAE is the penalty value, which is obtained by multiplying the time by the integral of the height error, and can converge quickly; e(t) is the function of the height error e changing with time; OS is the overshoot, which can limit the amplitude of the height of the laser device 115 exceeding the target value; t s is the adjustment time, which is the time required for the system to stabilize from startup to error within the range of ±2%; α, β and γ are weight coefficients, preferably α = 0.6, β = 0.3, γ = 0.1, focusing on fast response and low overshoot.

[0100] The fitness is calculated by the above formula, and the PID parameters of the current particle are input into the PID controller; the laser head height adjustment process is simulated, and the height error e(t), overshoot OS and adjustment time ts are recorded; the fitness value f is calculated, and the smaller the value, the better the parameter. The fitness function reflects the response speed, stability and accuracy of the PID control, ensuring that the optimization direction is consistent with the actual control.

[0101] Step 44: Improve the dynamic adaptive inertia weight and acceleration factor adjustment K p .

[0102] Step 441: adjust the inertia weight w of the current iteration loop according to the number of iterations. The formula is as follows:

[0103]

[0104] Where k is the current iteration number; k max is the maximum number of iterations, preferably 100.

[0105] The inertia weight w determines the proportion of the particle's inherited historical velocity and directly affects K p The original PSO algorithm uses a fixed inertia weight w, which makes it difficult to balance the rapid response of thick plate cutting and the fine adjustment of thin plates. The present invention proposes the above dynamic attenuation formula. Taking the maximum number of iterations as 100 as an example, when the thick plate is cut in the early stage (k<30), w=0.9, and the particles explore the high K with a large span. p range (200-300), quickly reduce the error. When a 20mm plate is detected, the initial K p = 250 can reduce the error from 16mm to 5mm within 10 iterations. In the late stage of thin plate cutting (k ≥ 30), w = 0.4, and the particle fine adjustment K p To the optimal value (such as K p =18) to avoid overshoot. In 1mm plate cutting, K p It gradually converges from 20 to 18, and the steady-state error is controlled within ±0.02mm.

[0106] Step 442, dynamically adjust the acceleration factors c1 and c2. When the number of iterations k is less than 30, c1 is 2.5 and c2 is 1.5; when the number of iterations k is greater than or equal to 30, c1 is 1.5 and c2 is 2.5.

[0107] The acceleration factors c1 (individual learning factor) and c2 (social learning factor) control the particle to move towards the individual optimum (p best ) and the global optimum (g best ). When k<30, it is in the exploration stage. Set c1=2.5, c2=1.5. The particles focus on individual experience and explore K extensively. p In thick plate cutting, if a particle’s p best =250 is better than the group mean, and the algorithm gives priority to this value to update K p When k ≥ 30, it is in the development stage, c1 = 1.5, c2 = 2.5, and the particles approach the optimal g of the group. best , accelerating convergence. When the global optimal K p =195, the algorithm guides other particles to move closer to this value to reduce oscillation.

[0108] Step 443, according to the height error e, obtain the error change rate ec, ec = de / dt. If |ec|>0.5mm / s (sudden change in plate thickness), reset the number of iterations k to 1 and execute step 441; if |ec|<0.1mm / s (steady-state condition), and at the same time, the number of iterations k is <30, reset the number of iterations k to 30 and execute step 441.

[0109] That is, if |ec|>0.5mm / s (sudden change in plate thickness), w=0.9 is forced to be reset and the exploration phase is entered, and K is redistributed. p Search resources. If |ec|<0.1mm / s (steady state), switch to the development stage and lock the optimal K p .

[0110] Step 45: Update the particle velocity position. The formula is as follows:

[0111]

[0112] Among them, r1 and r2 are random numbers (0, 1); the inertia term Inherit the parameter adjustment direction of the previous generation and maintain the search inertia. Individual cognitive items Learn from the particle's own historical optimal parameters. Social cognition item Learn from the optimal parameters of the group. If the current particle K p =150, individual optimal K p =140, optimal K for the group p =160, the update direction is to move closer to the middle value.p Beyond [0,P 电 ], it is truncated to the boundary value to prevent invalid parameters from entering the controller. p , the algorithm can balance fast response (high K p ) and stability (moderate K p ).

[0113] Step 46: Introduce the cross-cutting optimization mechanism (CSO mechanism for short) to optimize K p parameter.

[0114] Step 461: Perform a lateral cross operation on the particles whose speed and position are updated in step 45, and enhance K by exchanging dimensions between particles. p To prevent the algorithm from falling into local optimality, the horizontal crossover operation formula is as follows:

[0115]

[0116] For example, when the plate thickness is 20 mm and the maximum motor power is 300 watts, particle A (K p =180) and particle B(K p =220) after horizontal crossover, a new solution K is generated p =164 and K p =196, covering the medium and high gain range, suitable for 10-15mm plate cutting needs.

[0117] Step 462: perform longitudinal crossover on the particles whose speed and position are updated in step 45 to accelerate K p Converge to the global optimum, the formula is as follows:

[0118]

[0119] Assume that the global optimal K p =195, current particle K p =150 is updated to 172.5, quickly approaching the optimal solution and reducing the number of iterations.

[0120] Step 463: Perform the horizontal crossover of step 461 every ten iterations, perform the vertical crossover of step 462 every five iterations when the individual optimum is not updated, and retain the particles with the fitness value in the top 10%, so as to ensure that the high-quality solution is not destroyed.

[0121] Step 47: When the number of iterations reaches the maximum number of iterations, or the fitness value f < 0.1, or the global optimal solution is not updated for 20 consecutive iterations, the iteration ends and the final K is output. p value; otherwise continue iterating.

[0122] Setting the termination condition can avoid invalid calculations and ensure that the algorithm stops in time after the control requirements are met. For example, when the height error e of the laser device 115 is stabilized at ±0.05 mm, no further optimization is required.

[0123] Step 48: According to the actual height h of the laser device 115 collected by the visual sensor 114 in step 2 激 , get the instantaneous error, the formula is as follows:

[0124] e′(t)=h 目标 -h 激 (t)

[0125] In the formula, h 目标 h is the height to which the laser device 115 should be moved; 激 (t) is the real-time height of the laser device 115 collected by the visual sensor 114.

[0126] Step 49: Based on the instantaneous error obtained in step 48 and the final K obtained in step 47 p , and get the output proportional term P out , the formula is as follows:

[0127] P out =K P ·e′(t)

[0128] The larger the instantaneous error, the larger the proportional term of the output, and the higher the K p This speeds up the response but may cause overshoot or oscillation.

[0129] Step 410: According to the integral parameter K of the PID controller itself i and the differential parameter K d , and get the output integral term I out and the differential term D out , the formula is as follows:

[0130]

[0131] Where, T s is the sampling period, preferably 0.001 seconds; D filtered is the output differential term after suppressing high-frequency noise; s is the Laplace variable; δ is the time constant of the low-pass filter.

[0132] Integral term K i Accumulate historical errors, eliminate steady-state errors (such as static deviations caused by mechanical friction), high K i Accelerate steady-state convergence, but may introduce integral saturation. When the error exceeds the threshold (|e(t)|>0.5mm), the integral term calculation is suspended. At the same time, the maximum value of the integral term is limited, |I out ∣≤100.

[0133] Differential term K d Predict error change trend, suppress overshoot and oscillation, high K d Enhance system damping, but may amplify noise. Perform low-pass filtering on the derivative term to suppress high-frequency noise.

[0134] Step 411: Output proportional term P obtained in step 49 out The integral term I of the output obtained in step 410 is out , differential term D filtered , get the motor drive signal u(t), the formula is as follows:

[0135] u(t)=P out +I out +D filtered

[0136] Step 412: Obtain the voltage and current of the motor according to the motor drive signal u(t), thereby obtaining the output torque and speed of the motor, and the formula is as follows:

[0137]

[0138] Where τ is the torque, J is the moment of inertia, and B is the damping coefficient. The updated laser head height hactual(k+1)hactual(k+1) is input into the PID controller again to form a feedback closed-loop control.

[0139] The present invention generates K through SINE chaotic mapping p Initial value, to ensure the ability to search for the global optimal solution for thick and thin plate cutting. Nonlinear attenuation inertia weight and segmented acceleration factor to achieve a seamless transition from fast response to fine adjustment. Horizontal cross-enhancement diversity, longitudinal cross-acceleration convergence, to ensure control robustness under complex working conditions. Through the above improvements, the present invention enables the laser cutting system to adapt to 1 to 20 mm full thickness plates without manual intervention, significantly improving production efficiency and cutting quality. The improved PSO algorithm achieves high-precision positioning of the laser head in the drive motor system through rapid response of the proportional term, elimination of static error by the integral term, and suppression of oscillation by the differential term. First, the difference between the target and actual position is obtained in real time. Then the output signal is synthesized according to the P+I+D formula. Finally, the signal is converted into motor action, and the position is adjusted in a closed loop. By reasonably adjusting K p ,K i ,K d The system can adapt to different working conditions (thick plate / thin plate cutting) and balance speed, accuracy and stability.

[0140] Step 5: The motor adjusts the torque and the rotation speed according to the motor driving signal, thereby adjusting the height of the laser device 115.

[0141] Step 6: The laser device 115 starts cutting, and the monitoring system 104 monitors the thickness of the plate and the height of the laser device 115 in real time. Steps 2 to 5 are repeated until the cutting is completed.

[0142] Before starting this step, the smoke exhaust system 101 can also be started to facilitate the exhaust of cutting smoke during cutting.

[0143] Specifically, the PSO optimization algorithm dynamically adjusts the proportional control parameters of the PID controller by simulating swarm intelligence. First, the SINE chaotic map is used to generate an initial parameter combination that evenly covers the high, medium, and low gain intervals to avoid the local aggregation problem of traditional random initialization. The algorithm quantifies the PID parameter performance through the fitness function, using time multiplied by the absolute error integral, overshoot, and adjustment time as quantitative indicators to guide the particles to the optimal K p Value iteration. During the update process, the inertia weight decays nonlinearly with the number of iterations. In the early stage, the focus is on global exploration of high-gain parameters to quickly reduce the error, and in the later stage, the weight is reduced for fine adjustment. At the same time, horizontal cross-exchange of inter-particle dimensional information and vertical cross-learning of global optimal values ​​are introduced to break through the local optimal trap. When the maximum number of iterations or fitness threshold is reached, the optimal K is output. p Compared with the traditional method, the convergence speed is increased by 40%, the steady-state error is reduced by 60%, and the parameter adaptive matching of multi-thickness plate cutting is achieved.

[0144] Optimize K p The PID algorithm after the value is set drives the laser head to accurately position through a closed-loop control system. The real-time sensor detects the actual height of the laser head and compares it with the target value to generate an error signal. The proportional term quickly responds to the current deviation, the integral term accumulates historical errors to eliminate steady-state offsets, and the differential term predicts the change trend to suppress overshoot oscillations. The synthesized control quantity is converted into a motor drive signal, and the position of the laser head is dynamically adjusted through the transmission mechanism. The optimized parameters enable the system to complete positioning within 1.5 seconds in thick plate cutting, and the steady-state accuracy of thin plate cutting reaches ±0.02 mm. The full thickness adaptability is significantly enhanced, and ultimately high-efficiency, low-consumption, and high-precision adaptive laser cutting control is achieved.

[0145] In addition to the above embodiments, the present invention may also have other implementation modes. Any technical solutions formed by equivalent replacement or equivalent transformation shall fall within the protection scope required by the present invention.

Claims

1. A laser cutting system with adaptive plate thickness, characterized by: The invention comprises a rectangular parallelepiped mechanical platform (105), a monitoring system (104) arranged at one end of the mechanical platform (105) in the length direction, an optical system (100) arranged movably along the width direction of the mechanical platform (105), and a control system (102) arranged at the bottom of the mechanical platform (105); the optical system (100) is connected to the mechanical platform (105) through a transmission system (103) to achieve movement in three directions; the optical system comprises a laser tube (104) arranged parallel to the width direction of the mechanical platform (105); 6), a reflector A (107) and a reflector B (108) arranged at one end of the laser tube (106) and arranged opposite to each other, a laser device (115) arranged in the middle of the laser tube (106), and a reflector C (109) arranged on the laser device (115); the reflector A (107), the reflector B (108) and the reflector C (109) are at the same height; the control system (102) is respectively connected to the monitoring system (104), the optical system (100) and the transmission system (103).

2. The self-adaptive plate thickness laser cutting system according to claim 1, characterized in that: The transmission system (103) comprises two movable guide rails (110) arranged along the length direction of the mechanical platform (105) and respectively arranged on both sides of the length direction of the mechanical platform (105), a first drive motor (111) whose output end faces one of the movable guide rails (110) and meshes with a gear arranged on the guide rail (110), a second drive motor (112) whose output end is parallel to the width direction of the mechanical platform (105) and faces the inside of the mechanical platform (105), and a first movable lead screw (113) arranged parallel to the width direction of the mechanical platform (105) and fixedly connected to the output end of the second drive motor (112); the two ends of the optical system (100) are respectively slidably connected to the two movable guide rails (110), and the first drive motor (111) is meshed with a gear arranged on the guide rail (110). The fixed end of (110) is fixedly connected to the optical system (100), and a slider is arranged at a corresponding position of the optical system (100), and the slider cooperates with the first movable lead screw (113); the transmission system (103) also includes a second movable lead screw (116) arranged along the height direction of the mechanical platform (105) and one end of which cooperates with the slider on the optical system (100), and a third drive motor (117) whose output end faces the mechanical platform (105) and is fixedly connected to the second movable lead screw (116); the laser device (115) is fixedly connected to the fixed end of the third drive motor (117), and the control system (102) is respectively connected to the first drive motor (111), the second drive motor (112) and the third drive motor (117).

3. The self-adaptive plate thickness laser cutting system according to claim 2, characterized in that: The monitoring system (104) comprises a visual sensor (114) fixedly connected to a fixed end of the third drive motor (117) and a high-definition camera arranged at one end of the mechanical platform (105), and the visual sensor (114) and the high-definition camera are connected to the control system (104).

4. The self-adaptive plate thickness laser cutting system according to claim 3, characterized in that: The monitoring system (104) further comprises pressure sensors arranged on the movable guide rail (110), the first movable lead screw (113) and the second movable lead screw (116).

5. The self-adaptive plate thickness laser cutting system according to claim 3, characterized in that: The sampling frequency of the visual sensor (114) is 1 kHz to 10 kHz.

6. The self-adaptive plate thickness laser cutting system according to claim 3, characterized in that: The mechanical platform (105) is provided with a smoke exhaust system (101) away from the monitoring system (104), wherein the smoke exhaust system (101) comprises a negative pressure fan (118) provided on one side of the mechanical platform (105), a smoke exhaust duct provided inside the mechanical platform (105), and a drawer provided at the bottom of the mechanical platform (105).

7. The self-adaptive plate thickness laser cutting system according to claim 3, characterized in that: The optical system (100) further comprises an adjustable mirror frame, and the reflector A (107), the reflector B (108) and the reflector C (109) are mounted on the adjustable mirror frame.

8. A working method of the laser cutting system with adaptive plate thickness according to any one of claims 3 to 7, characterized in that: The steps include: S1, placing the plate on the mechanical platform (105), moving the guide rail (110) and the first driving motor (111) to move the laser device (115) to the initial cutting area; S2, the high-definition camera of the monitoring system (104) captures an image and sends the image to the control system (102), and the visual sensor (114) collects the height h of the laser device (115) in real time 激 , and sent to the control system (102); S3. The processor in the control system (102) processes the image to obtain the thickness H of the plate. 实际 ; S4. The processor in the control system (102) uses the improved PSO algorithm to calculate the K of the PID controller. p Optimize the parameters and use the optimized K p The K parameter of the PID controller i and K d Parameter synthesis output, to obtain the motor drive signal; S5, the motor adjusts the height of the laser device (115) according to the torque and speed of the motor driving signal; S6. The laser device (115) starts cutting, and the monitoring system (104) monitors the thickness of the plate and the height of the laser device (115) in real time. Steps S2 to S5 are repeated until the cutting is completed.

9. The working method of the laser cutting system with adaptive plate thickness according to claim 8, characterized in that: The specific steps of step S4 are as follows: S41: The thickness H of the plate obtained in step S3 实际 , calculate the height error e, if |e|>0.1mm, execute step S42, otherwise terminate the optimization and proceed directly to cutting; the calculation formula of e is as follows: e=h 激 -H 实际 -ε In the formula, h 激 H is the height of the laser device (115); 实际 is the thickness of the plate; ε is the reserved height; S42, using SINE chaotic mapping to initialize PID parameter K p , the formula is as follows: Where P 电 is the maximum output power of the motor; is the initial value of the PID controller parameters; S43. Construct a fitness function according to the adjustment time, overshoot and penalty value. The formula is as follows: f=α·ITAE+β·OS+γ·t s Where, f is the fitness value; ITAE is the penalty value; OS is the overshoot; t s is the adjustment time; α, β and γ are weight coefficients; S44, improved dynamic adaptive inertia weight and acceleration factor adjustment K p ; S441. Adjust the inertia weight w of the current iteration cycle according to the number of iterations. The formula is as follows: Where k is the current iteration number; k max is the maximum number of iterations; S442, dynamically adjust the acceleration factors c1 and c2. When the number of iterations k is less than 30, c1 is 2.5 and c2 is 1.5; when the number of iterations k is greater than or equal to 30, c1 is 1.5 and c2 is 2.5; S443. According to the height error e, the error change rate ec is obtained, ec=de / dt. If |ec|>0.5mm / s, the number of iterations k is reset to 1, and step S441 is executed; if |ec|<0.1mm / s, and the number of iterations k at this time is <30, the number of iterations k is reset to 30, and step S441 is executed; S45. Update particle velocity position. The formula is as follows: Wherein, r1 and r2 are random numbers of (0, 1); S46, introduce vertical and horizontal cross optimization mechanism to optimize K p parameter; S461, perform a lateral cross operation on the particles after the speed and position are updated in step S45, the formula is as follows: S462, perform longitudinal crossover on the particles after the speed and position are updated in step S45, the formula is as follows: S463, perform the horizontal crossover of step S461 every ten iterations, and perform the vertical crossover of step S462 every five iterations when the individual optimum is not updated; S47, when the number of iterations reaches the maximum number of iterations, or the fitness value f < 0.1, or the global optimal solution is not updated for 20 consecutive iterations, the iteration ends and the final K is output. p value; otherwise continue to iterate; S48, according to the actual height h of the laser device (115) collected by the visual sensor (114) in step S2 激 , get the instantaneous error, the formula is as follows: e′(t)=h 目标 -h 激 (t) In the formula, h 目标 h is the height to which the laser device (115) should be moved; 激 (t) is the real-time height of the laser device (115) collected by the visual sensor (114); S49, based on the instantaneous error obtained in step S48 and the final K obtained in step S47 p , and get the output proportional term P out , the formula is as follows: P out =K P ·e′(t) S410, according to the integral parameter K of the PID controller itself i and the differential parameter K d , and get the output integral term I out and the differential term D out , the formula is as follows: Where, T s is the sampling period, preferably 0.001 seconds; D filtered is the output differential term after suppressing high-frequency noise; s is the Laplace variable; δ is the time constant of the low-pass filter; S411, output proportional term P obtained in step S49 out The integral term I of the output obtained in step S410 out , differential term D filtered , get the motor drive signal u(t), the formula is as follows: u(t)=P out +I out +D filtered S412, obtaining the voltage and current of the motor according to the motor drive signal u(t), thereby obtaining the output torque and speed of the motor, the formula is as follows: Where τ is the torque, J is the moment of inertia, and B is the damping coefficient.

10. The working method of the laser cutting system with adaptive plate thickness according to claim 9, characterized in that: The values ​​of the weight coefficients α, β and γ in step S43 are 0.6, 0.3 and 0.1 respectively.

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