CN116352231A - Adaptive Control Method for Longitudinal Wire Filling Position of Filling Wire GTAW Based on Arc Sensing - Google Patents

Abstract

The invention relates to an arc sensing-based adaptive control method for a longitudinal filler wire position of a filler wire GTAW. Aiming at the difficult problem that the longitudinal filler wire position cannot be adaptively controlled in the GTAW process, the invention discloses an arc sensing-based filler wire GTAW longitudinal filler wire position adaptive control method. The arc starting state is identified by using a welding wire touch GTAW arc starting state sensing method, the longitudinal position of the welding wire in an electric arc is identified by using a welding wire longitudinal position sensing method, the wire filling position of the welding wire is self-adapted by using a self-adaptive wire filling device, and the self-adaptive control of the wire filling position of the wire filling GTAW is realized by using a wire filling GTAW longitudinal wire filling position self-adaptive control method.

Description

Adaptive Control Method for Longitudinal Wire Filling Position of Filling Wire GTAW Based on Arc Sensing

technical field

The invention relates to the field of adaptive control of the longitudinal wire filling position of the wire filling GTAW, and relates to an arc sensing-based adaptive control method for the longitudinal wire filling position of the wire filling GTAW.

technical background

GTAW (non-melting electrode gas shielded welding) is widely used in aerospace, marine engineering equipment, nuclear power construction and other important fields. high demands. The stability of the arc and the accuracy of the wire filling position in the GTAW process have a very important impact on the welding quality and efficiency. Too high or too low distance between the wire filling position and the molten pool will affect the droplet transfer mode, thereby affecting the welding quality and welding efficiency. However, there is currently no adaptive control method for the longitudinal wire filling position of the wire filling GTAW. To solve this problem, the present invention discloses an adaptive control method for the longitudinal wire filling position of the wire filling GTAW based on arc sensing.

Contents of the invention

An arc sensor-based adaptive control method for longitudinal wire filling position in GTAW, which is used for adaptive control of longitudinal wire filling position in the GTAW process. The system schematic diagram is shown in Figure 1, and it is characterized in that: The arc sensor-based adaptive control method for wire-filling GTAW longitudinal wire-filling position is realized by the arc-sensing-based wire-filling GTAW longitudinal wire-filling position adaptive control system. The adaptive control system consists of a dual-channel arc monitoring system, an adaptive wire filling device, an arc start monitoring system, and an adaptive controller for the longitudinal wire filling position of GTAW. Use the welding wire touch GTAW arc starting state perception method to identify the arc starting state, use the welding wire longitudinal position sensing method to identify the longitudinal position of the welding wire in the arc, use the self-adaptive wire filling device to adapt the welding wire filling position, and use the filling wire GTAW to fill the wire longitudinally The position adaptive adjustment control method realizes the self-adaptive control of the longitudinal wire filling position of the wire filling GTAW. The longitudinal wire filling position is the distance between the welding wire and the workpiece on the axis of the tungsten pole.

The described method of sensing the welding wire touching the GTAW arcing state is realized by the arcing state monitoring system, which is used to monitor the GTAW arcing state and control the system power switch to prevent the high frequency and high voltage from filling the arc sensor based on the GTAW arcing process. The interference of the wire GTAW longitudinal wire filling position adaptive control system, and the schematic diagram of the arcing monitoring system are shown in Figure 2. The arcing state monitoring system is composed of a peripheral monitoring circuit and an arcing monitoring system controller. The peripheral monitoring circuit is used to monitor the arcing status signal and transmit the signal to the arcing monitoring system controller. The controller of the arc-starting monitoring system sends an instruction to start arc-monitoring through the output signal, and judges whether the arc-starting is successful or not through the input signal. When starting the monitoring of the arcing status, the controller of the arcing monitoring system controls the peripheral monitoring circuit to enter the state of starting the arcing monitoring by outputting a high level. At this time, the wire filling mechanism starts to continuously fill the wire. low level. When the welding wire touches the workpiece, the controller of the arc detection system 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 start. When the arc detection system controller at the input signal end When a low level is detected, the GTAW arc starts successfully.

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

The self-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 installation mechanism is used for the fast connection between the self-adaptive wire filling device and the GTAW welding torch. The servo motor communicates with the control bus and the longitudinal wire filling position adaptive controller of the wire filling GTAW, and realizes the driving of the moving shaft. The clamping mechanism is used to securely connect the self-adaptive wire filling device with 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 of the wire filling receives the tungsten extreme arc signal and the welding wire end arc signal obtained by the dual-channel arc monitoring system through the communication bus, uses the GTAW longitudinal wire filling position calculation method to obtain the wire filling position, and controls The self-adaptive wire filling device adjusts the longitudinal wire filling position. The potential distribution in the entire arc is uneven, the potential distribution curves of the cathode area and the anode area have a large slope, and the potential distribution in the arc column area is uniform, so in order to reduce the interference between the cathode area and the anode area during the calculation of the arc length, The calculation method of the GTAW longitudinal wire filling position is as follows:

(1) When U ₁ -U ₂ ≥ U ₂ , L ₂ =f(U ₁ )-f(U ₁ -U ₂ );

(2) When U ₁ -U ₂ <U ₂ , L ₂ =f(U ₂ );

Among them, U ₁ is the arc voltage between the tungsten electrode and the workpiece; U ₂ is the arc voltage between the welding wire and the workpiece; L ₂ 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 self-adaptive adjustment control method for the longitudinal position of filling wire GTAW is to realize the adaptive control of the longitudinal position of filling wire GTAW by monitoring the variation and rate of change of the longitudinal position of the welding wire, and its principle is shown in FIG. 5 .

Beneficial effects of the invention:

The invention relates to an arc sensing-based self-adaptive control method for the longitudinal wire filling position of a wire filling GTAW. Aiming at the problem that the longitudinal wire filling position cannot be adaptively controlled in the GTAW process, the invention discloses a method for adaptively controlling the longitudinal wire filling position of the wire filling GTAW based on arc sensing. Use the welding wire touch GTAW arc starting state perception method to identify the arc starting state, use the welding wire longitudinal position sensing method to identify the longitudinal position of the welding wire in the arc, use the self-adaptive wire filling device to adapt the welding wire filling position, and use the filling wire GTAW to fill the wire longitudinally The position adaptive adjustment control method realizes the self-adaptive control of the longitudinal wire filling position of the wire filling GTAW. The present invention overcomes the difficult problem that the longitudinal wire filling position cannot be controlled in real time and adaptively in the current wire filling GTAW process, and is expected to further improve the automation and intelligence level of the wire filling GTAW.

Description of drawings

Fig. 1 is a schematic diagram of an adaptive control system for longitudinal wire filling position of wire filling GTAW based on arc sensing.

Figure 2 is a schematic diagram of the arc starting state monitoring system.

Fig. 3 is a model diagram of the calculation method for filling wire position.

In the figure: L ₁ is the distance between the tungsten pole and the workpiece, that is, the arc length, and L ₂ is the distance between the welding wire and the workpiece on the axis of the tungsten pole.

Fig. 4 is a flow chart of an adaptive control method for longitudinal wire filling position of the wire filling GTAW based on arc sensing.

Fig. 5 is a schematic diagram of the control method for adaptive adjustment of the longitudinal wire filling position of the wire filling GTAW.

In the figure: q ₀ , q ₁ , and q ₂ are calculated by formula (1). k is the kth calculation cycle. e(k) is calculated by formula (2).

ec(k) is calculated by formula (3). K _p , K _i and K _d are PID control parameters.

In the formula, K _p is the proportional coefficient, T _I is the integral time constant, and T _D is the differential time constant.

e(k)=L ₂ (k)-L _2P (2)

In the formula, L ₂ (k) is the distance between the welding wire and the workpiece in the kth calculation cycle, and L _2P is the preset longitudinal wire filling position.

ec(k)=e(k)-e(k-1) (3)

Detailed ways

In order to better express the technical solutions and beneficial effects of the entire invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and implementation cases, and its overall working process is shown in Figure 4. Embodiments of the present invention are not limited thereto.

Step 1: Arcing Status Monitoring

In order to avoid the interference of high frequency and high voltage in the GTAW arcing process on the arc sensor-based adaptive control system for the longitudinal filling position of GTAW, the present invention uses the arcing status monitoring system shown in Figure 2 to monitor the GTAW arcing status.

When starting the monitoring of the arcing state, the controller of the arcing monitoring system controls the peripheral monitoring circuit to enter the state of starting the arcing monitoring by outputting a high level, that is, the contact 1 and the contact 2 of the relay in Figure 2 are closed, and the contact 3 and the contact 4 are closed. , at this time, the wire filling mechanism starts to continuously fill wire slowly, and the arc detection system controller at the input signal end detects a low level. When the welding wire touches the workpiece, the controller of the arc detection monitoring system at the input signal terminal 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 GTAW starts arcing smoothly, the welding wire melts, and the welding wire is no longer in contact with the workpiece. At this time, the input signal is detected to be low again. When the controller of the arc detection monitoring system at the input signal end detects a low level again, the GTAW arc starts successfully.

Step 2: Adaptive control of the longitudinal wire filling position of GTAW during the arc length adjustment process after arc start

After the arc is started, the arc length is elongated. At the same time, the dual-channel arc monitoring system in Figure 1 monitors the arc data in real time and transmits the arc data to the wire filling GTAW longitudinal filling position adaptive controller through the communication bus. The wire position adaptive controller uses the GTAW longitudinal wire filling position calculation method to calculate L ₁ and L ₂ in real time until L ₁ = L _1P , and the arc length stops pulling up, where L _1P is the preset arc length. When L ₁ ＝L _1P , the adaptive controller of the longitudinal wire filling position of the wire filling GTAW sends control instructions to the servo motor of the adaptive wire filling device through the control bus, and adjusts the longitudinal wire filling position of the wire filling GTAW until L ₂ ＝L _2P , where L _2P is the preset longitudinal wire filling position.

Step 3: Adaptive control of the longitudinal wire filling position of GTAW during the welding process

In the GTAW process, when the arc length changes due to tungsten burning or thermal deformation of the workpiece, in order to ensure good welding quality, it is necessary to adaptively control the longitudinal filling position of the filling wire GTAW. When |L ₂ -L _2P |≥L _ST , use the adaptive control method for adjusting the longitudinal wire filling position of GTAW shown in Figure 5 to perform adaptive control on the longitudinal wire filling position of GTAW, where L _ST is the change in the longitudinal wire filling position threshold.

Claims (4)

1. An adaptive control method for longitudinal wire filling position of wire filling GTAW based on arc sensing, which is used for longitudinal wire filling position adaptive control in GTAW process, characterized in that: the longitudinal wire filling GTAW based on arc sensing The self-adaptive control method of wire filling position is realized by the wire filling GTAW longitudinal wire position adaptive control system based on arc sensing, and the described arc sensing based wire filling GTAW longitudinal wire position adaptive control system is monitored by a dual-channel arc system, self-adaptive wire filling device, arc start monitoring system and wire filling GTAW longitudinal wire position adaptive controller; use the welding wire touch GTAW arc start state sensing method to identify the arc start state, and use the welding wire longitudinal position sensing method to identify the welding wire in the Longitudinal position in the arc, using the self-adaptive wire filling device to adapt the welding wire filling position, using the filling wire GTAW longitudinal filling position adaptive adjustment control method to realize the filling wire GTAW longitudinal filling position adaptive control; the longitudinal filling wire The position is the distance from the welding wire to the workpiece on the axis of the tungsten pole. 2. A method for self-adaptive control of wire filling GTAW longitudinal filling position based on arc sensing according to claim 1, characterized in that: the method for sensing the arcing state of the welding wire touching the GTAW is to monitor the arcing state Realized by the system, it is used to monitor the GTAW arcing status and control the system power switch to prevent the interference of high frequency and high voltage on the GTAW longitudinal filling position adaptive control system based on arc sensing during the GTAW arcing process; the arcing The state monitoring system is composed of a peripheral monitoring circuit and an arcing monitoring system controller; the peripheral monitoring circuit is used to monitor the arcing status signal and transmit the signal to the arcing monitoring system controller; the arcing monitoring system controller Send out the start arc monitoring command through the output signal, and judge whether the arc is successful or not through the input signal. 3. A method for self-adaptive control of the longitudinal position of filling wire GTAW based on arc sensing according to claim 1, characterized in that: the method for sensing the longitudinal position of the welding wire consists of a dual-channel arc monitoring system, adaptive filling The wire device and the wire filling GTAW longitudinal wire position adaptive controller are realized; 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 pass the arc signal through the control The bus is transmitted to the filler wire GTAW longitudinal wire position adaptive controller; the tungsten end arc signal is the arc voltage signal between the tungsten electrode and the workpiece; the welding wire end arc signal is the arc voltage between the welding wire and the workpiece signal; the self-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 installation The mechanism is used for the fast connection between the adaptive wire filling device and the GTAW welding torch; the servo motor communicates with the control bus and the GTAW longitudinal wire filling position adaptive controller for wire filling, and realizes the drive of the moving shaft; the described The clamping mechanism is used to securely connect the self-adaptive wire filling device with the wire feeding tube; the moving shaft is driven by the servo motor to control the adjustment of the longitudinal position of the welding wire; the self-adaptive controller for the longitudinal position of the wire filling GTAW Receive the tungsten extreme arc signal and the welding wire end arc signal obtained by the dual-channel arc monitoring system through the communication bus, use the GTAW longitudinal wire filling position calculation method to obtain the wire filling position, and control the adaptive wire filling device to adjust the longitudinal wire filling position. 4. A method for self-adaptive control of wire filling GTAW longitudinal filling position based on arc sensing according to claim 1, characterized in that: the self-adaptive adjustment control method for longitudinal filling position of wire filling GTAW is through monitoring The change amount and change rate of the longitudinal position of the welding wire are used to realize the adaptive control of the longitudinal position of the filler wire GTAW.

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