Adaptive control method of longitudinal wire position in GTAW with wire filling based on arc sensing

Abstract

The present invention relates to a method for adaptively controlling the longitudinal wire position of a GTAW wire-filler based on arc sensing. Aiming at the problem that the longitudinal wire position of a GTAW wire-filler cannot be adaptively controlled during the GTAW process, the present invention discloses a method for adaptively controlling the longitudinal wire position of a GTAW wire-filler based on arc sensing. The arc starting state is identified by a method for sensing the arc starting state of the GTAW wire-touching arc, the longitudinal position of the welding wire in the arc is identified by a method for sensing the longitudinal position of the welding wire, the welding wire filling position is adaptively adjusted by an adaptive wire-filler device, and the longitudinal wire filling position adaptive adjustment control method of the GTAW wire-filler is used to achieve adaptive control of the longitudinal wire filling position of the GTAW wire-filler.

Description

Technical Field

[0001] The invention relates to the field of GTAW longitudinal wire filling position adaptive control, and is an arc sensing-based GTAW longitudinal wire filling position adaptive control method. Technical Background

[0002] GTAW (gas shielded arc welding) is widely used in important fields such as aerospace, marine equipment, and nuclear power construction. In particular, the rapid development of arc additive technology in recent years has put forward higher requirements for the automation and intelligence of GTAW with filler wire. The stability of the arc and the accuracy of the filler wire position in the GTAW process have a very important influence on the welding quality and efficiency. If the filler wire position is too high or too low from the molten pool, it will affect the droplet transfer mode, and then affect the welding quality and welding efficiency. However, there is currently no method for adaptively controlling the longitudinal filler wire position of GTAW with filler wire. In response to this problem, the present invention discloses a method for adaptively controlling the longitudinal filler wire position of GTAW with filler wire based on arc sensing. Summary of the invention

[0003] A method for adaptive control of the longitudinal wire position of GTAW with wire filling based on arc sensing is used for adaptive control of the longitudinal wire position in the GTAW process. The system schematic diagram is shown in FIG. Figure 1 As shown, it is characterized in that: the arc sensing-based GTAW longitudinal wire position adaptive control method is implemented by the arc sensing-based GTAW longitudinal wire position adaptive control system, and the arc sensing-based GTAW longitudinal wire position adaptive control system is composed of a dual-channel arc monitoring system, an adaptive wire filling device, an arc starting monitoring system and a GTAW longitudinal wire filling position adaptive controller. The arc starting state is identified by the welding wire touching the GTAW arc starting state sensing method, the longitudinal position of the welding wire in the arc is identified by the welding wire longitudinal position sensing method, the welding wire filling position is adaptively adjusted by the adaptive wire filling device, and the longitudinal wire filling position adaptive control of the GTAW longitudinal wire filling position is realized by the GTAW longitudinal wire filling position adaptive adjustment control method. The longitudinal wire filling position is the distance between the welding wire and the workpiece on the tungsten electrode axis.

[0004] The welding wire touches the GTAW arc starting state sensing method is implemented by the arc starting state monitoring system, which is used to monitor the GTAW arc starting state and control the system power switch to prevent the high frequency and high voltage from interfering with the GTAW longitudinal wire position adaptive control system based on arc sensing during the GTAW arc starting process. The schematic diagram of the arc starting monitoring system is shown in FIG. Figure 2As shown. The arc starting state monitoring system is composed of a peripheral monitoring circuit and an arc starting monitoring system controller. The peripheral monitoring circuit is used to monitor the arc starting state signal and transmit the signal to the arc starting monitoring system controller. The arc starting monitoring system controller issues an arc starting monitoring instruction through an output signal, and determines whether the arc starting is successful through an input signal. When starting the arc starting state monitoring, the arc starting monitoring system controller controls the peripheral monitoring circuit to enter the arc starting monitoring state by outputting a high level. At this time, the wire filling mechanism starts to fill the wire continuously, and the arc starting monitoring system controller at the input signal end detects a low level. When the welding wire touches the workpiece, the arc starting monitoring system controller at the input signal end detects a high level. At this time, the wire filling is stopped, and the welding switch is turned on for high-frequency and high-voltage arc starting. When the arc starting monitoring system controller at the input signal end detects a low level again, the GTAW arc starts successfully.

[0005] The method for sensing the longitudinal position of the welding wire is implemented by a dual-channel arc monitoring system, an adaptive wire-filling device and a GTAW longitudinal wire-filling position adaptive controller. The dual-channel arc monitoring system has two arc monitoring channels, which are used to monitor the arc signal at the welding wire end and the arc signal at the tungsten end, respectively, and transmit the arc signal to the GTAW longitudinal wire-filling position adaptive controller through a control bus. The tungsten end arc signal is an arc voltage signal between the tungsten electrode and the workpiece. The wire end arc signal is an arc voltage signal between the welding wire and the workpiece.

[0006] The adaptive wire-filling device is composed of an insulating ring, a mounting mechanism, a servo motor, a clamping mechanism and a moving shaft. The insulating ring is used to isolate the arc signal at the end of the welding wire and the arc signal at the end of the tungsten wire. The mounting mechanism is used to fasten the adaptive wire-filling device to the GTAW welding gun. The servo motor communicates with the GTAW longitudinal wire-filling position adaptive controller through the control bus and drives the moving shaft. The clamping mechanism is used to fasten the adaptive wire-filling device to the wire feeding tube. The moving shaft controls the longitudinal position adjustment of the welding wire under the drive of the servo motor. The GTAW longitudinal wire-filling position adaptive controller receives the tungsten end arc signal and the welding wire end arc signal obtained by the dual-channel arc monitoring system through the communication bus, obtains the wire-filling position by using the GTAW longitudinal wire-filling position calculation method, and controls the adaptive wire-filling device to adjust the longitudinal wire-filling position. The potential distribution in the entire arc is uneven. The slopes of the potential distribution curves in the cathode and anode regions are large, while the potential distribution in the arc column region is uniform. Therefore, in order to reduce the interference between the cathode and anode regions during the arc length calculation process, the GTAW longitudinal wire filling position calculation method is as follows:

[0007] (1) When U1-U2≥U2, L2=f(U1)-f(U1-U2);

[0008] (2) When U1-U2<U2, L2=f(U2);

[0009] Among them, U1 is the arc voltage between the tungsten electrode and the workpiece; U2 is the arc voltage between the welding wire and the workpiece; L2 is the distance between the welding wire and the workpiece; f is the linear function relationship between the arc length and the arc voltage.

[0010] The method for adaptively adjusting the longitudinal position of the GTAW welding wire is to realize the adaptive control of the longitudinal position of the GTAW welding wire by monitoring the change amount and change rate of the longitudinal position of the welding wire. The principle is as follows: Figure 5 shown.

[0011] Beneficial effects of the invention:

[0012] The present invention relates to an adaptive control method for the longitudinal wire filling position of GTAW with wire filling based on arc sensing. Aiming at the problem that the longitudinal wire filling position cannot be adaptively controlled in the GTAW process, the present invention discloses an adaptive control method for the longitudinal wire filling position of GTAW with wire filling based on arc sensing. The arc starting state is identified by the welding wire touching GTAW arc starting state sensing method, the longitudinal position of the welding wire in the arc is identified by the welding wire longitudinal position sensing method, the welding wire filling position is adaptively adjusted by an adaptive wire filling device, and the longitudinal wire filling position adaptive control of GTAW with wire filling is realized by the adaptive adjustment control method of the longitudinal wire filling position of GTAW with wire filling. The present invention overcomes the problem that the longitudinal wire filling position cannot be adaptively controlled in real time in the current GTAW process with wire filling, and is expected to further improve the automation and intelligent level of GTAW with wire filling. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is the schematic diagram of the adaptive control system for the longitudinal wire-filling position of GTAW based on arc sensing.

[0014] Figure 2 This is the schematic diagram of the arc starting status monitoring system.

[0015] Figure 3 This is a model diagram for the calculation method of the filling wire position.

[0016] In the figure: L1 is the distance between the tungsten electrode and the workpiece, that is, the arc length, and L2 is the distance between the welding wire and the workpiece on the axis of the tungsten electrode.

[0017] Figure 4 The flowchart of the adaptive control method of the longitudinal wire-filling position of GTAW with wire-filling based on arc sensing.

[0018] Figure 5 This is the schematic diagram of the adaptive control method for the longitudinal filling wire position in GTAW with filling wire.

[0019] In the figure: q0, q1, q2 are calculated by equation (1). k is the kth calculation cycle. e(k) is calculated by equation (2).

[0020] ec(k) is calculated by equation (3). p , K i and K d is the PID control parameter.

[0021]

[0022] In the formula, K p is the proportionality coefficient, T I is the integration time constant, T D is the differential time constant.

[0023] e(k)=L2(k)-L 2P (2)

[0024] Where L2(k) is the distance between the welding wire and the workpiece in the kth calculation cycle, L 2P To preset the longitudinal filling wire position.

[0025] ec(k)=e(k)-e(k-1) (3) DETAILED DESCRIPTION

[0026] In order to better express the technical solution and beneficial effects of the entire invention, the present invention is further described in detail below with reference to the accompanying drawings and implementation examples. The overall working process is as follows: Figure 4 The embodiments of the present invention are not limited thereto.

[0027] Step 1: Arcing status monitoring

[0028] In order to avoid the interference of high frequency and high voltage on the GTAW longitudinal wire position adaptive control system based on arc sensing during the GTAW arc starting process, the present invention utilizes the following method: Figure 2 The arc starting status monitoring system shown monitors the GTAW arc starting status.

[0029] When the arcing state monitoring starts, the arcing monitoring system controller controls the peripheral monitoring circuit to enter the arcing monitoring state by outputting a high level. Figure 2 The middle relay contact 1 and contact 2 are closed, and contact 3 and contact 4 are closed. At this time, the wire filling mechanism starts to fill the wire slowly and continuously, and the arc starting monitoring system controller at the input signal end detects a low level. When the welding wire touches the workpiece, the arc starting monitoring system controller at the input signal end detects a high level. At this time, the wire filling is stopped, and the welding switch is turned on for high-frequency and high-voltage arc starting. When the GTAW arc is successfully started, the welding wire melts, and the welding wire is no longer in contact with the workpiece. At this time, the input signal detects a low level again. When the arc starting monitoring system controller at the input signal end detects a low level again, the GTAW arc is successfully started.

[0030] Step 2: Arc length adjustment process after arc starting GTAW longitudinal wire position adaptive control of wire filling

[0031] After the arc is struck, the arc length lengthens. Figure 1 The dual-channel arc monitoring system monitors the arc data in real time and transmits the arc data to the GTAW longitudinal wire position adaptive controller through the communication bus. The GTAW longitudinal wire position adaptive controller uses the GTAW longitudinal wire position calculation method to calculate L1 and L2 in real time until L1 = L 1P , arc length stops pulling up, where L 1P is the preset arc length. When L1=L 1P When L2 is reached, the GTAW longitudinal wire position adaptive controller sends a control command to the servo motor of the adaptive wire filling device through the control bus to adjust the GTAW longitudinal wire filling position until L2 = L 2P , where L 2P To preset the longitudinal filling wire position.

[0032] Step 3: Adaptive control of the longitudinal wire position of GTAW wire during welding

[0033] During the GTAW process, when the arc length changes due to tungsten electrode burning or workpiece thermal deformation, in order to ensure good welding quality, the longitudinal wire position of the GTAW wire must be adaptively controlled. 2P |≥L ST Time use Figure 5 The GTAW longitudinal wire filling position adjustment adaptive control method shown in the figure performs adaptive control on the GTAW longitudinal wire filling position, wherein L ST It is the threshold value of longitudinal filling wire position change.

Claims

1. A method for adaptively controlling the longitudinal wire position of a GTAW process with wire filling based on arc sensing, which is used for adaptively controlling the longitudinal wire position of the GTAW process, and is characterized by: The described adaptive control method for longitudinal wire filling position in wire-fed GTAW based on arc sensing is realized by an adaptive control system for longitudinal wire filling position in wire-fed GTAW based on arc sensing. The adaptive control system for longitudinal wire filling position in wire-fed GTAW based on arc sensing consists of a dual-channel arc monitoring system, an adaptive wire filling device, an arc starting monitoring system, and an adaptive controller for longitudinal wire filling position in wire-fed GTAW. The arc starting state is identified using the method for sensing the arc starting state of GTAW by touching the welding wire. The longitudinal position of the welding wire in the arc is identified using the method for sensing the longitudinal position of the welding wire. The adaptive wire filling device is used to adaptively adjust the wire filling position. The longitudinal wire filling position refers to the distance between the welding wire and the workpiece on the axis of the tungsten electrode. The method for sensing the longitudinal position of the welding wire is realized by the dual-channel arc monitoring system, the adaptive wire filling device, and the adaptive controller for longitudinal wire filling position in wire-fed GTAW. The dual-channel arc monitoring system has two arc monitoring channels, which are respectively used to monitor the arc signals at the wire end and the tungsten electrode end and transmit the arc signals to the adaptive controller for longitudinal wire filling position in wire-fed GTAW through the control bus. The arc signal at the tungsten electrode end is the arc voltage signal between the tungsten electrode and the workpiece. The arc signal at the wire end is the arc voltage signal between the welding wire and the workpiece. The adaptive controller for longitudinal wire filling position in wire-fed GTAW receives the arc signal at the tungsten electrode end and the arc signal at the wire end obtained by the dual-channel arc monitoring system through the communication bus, obtains the wire filling position using the calculation method for GTAW longitudinal wire filling position, and controls the adaptive wire filling device to adjust the longitudinal wire filling position. The calculation method for GTAW longitudinal wire filling position is as follows: when U1 - U2 ≥ U2, L2 = f(U1) - f(U1 - U2); when U1 - U2 < U2, L2 = f(U2), where U1 is the arc voltage between the tungsten electrode and the workpiece; U2 is the arc voltage between the welding wire and the workpiece; L2 is the distance between the welding wire and the workpiece; f is the linear function relationship between the arc length and the arc voltage. The method for sensing the arc starting state of GTAW by touching the welding wire is realized by the arc starting monitoring system, which is used to monitor the arc starting state of GTAW and control the power switch of the system to prevent the interference of high-frequency high voltage on the adaptive control system for longitudinal wire filling position in wire-fed GTAW during the GTAW arc starting process. The arc starting monitoring system consists of a peripheral monitoring circuit and an arc starting monitoring system controller. The peripheral monitoring circuit is used to monitor the arc starting state signal and transmit the signal to the arc starting monitoring system controller. The arc starting monitoring system controller issues a start arc monitoring command through the output signal and judges whether the arc starting is successful through the input signal.

2. The method for controlling the longitudinal wire position of a GTAW wire-filling machine based on arc sensing according to claim 1, characterized in that: The adaptive wire filling device is composed of an insulating ring, a mounting mechanism, a servo motor, a clamping mechanism and a moving shaft; the insulating ring is used to isolate the arc signal at the welding wire end and the arc signal at the tungsten end; the mounting mechanism is used to fasten the adaptive wire filling device to the GTAW welding gun; the servo motor communicates with the GTAW longitudinal wire filling position adaptive controller through the control bus and drives the moving shaft; the clamping mechanism is used to fasten the adaptive wire filling device to the wire feeding tube; the moving shaft controls the longitudinal position adjustment of the welding wire under the drive of the servo motor.

3. The method for controlling the longitudinal wire position of a GTAW wire-filling machine based on arc sensing according to claim 1, characterized in that: The method for adaptively adjusting and controlling the longitudinal position of the GTAW welding wire achieves adaptive control of the longitudinal position of the GTAW welding wire by monitoring the change amount and change rate of the longitudinal position of the welding wire.

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