Welding gun current force control composite positioning sensing method, system and storage medium

Abstract

The application discloses a force control composite positioning sensing method and system based on a welding gun current, and a storage medium, relates to the field of automatic welding, and comprises the following steps: acquiring a welding gun pressure signal and a welding machine arc current signal; in the process of positioning scanning, the welding gun is controlled to move, so that the welding wire keeps in contact with the surface of a workpiece; based on the space-time composite change of the pressure signal and the arc current signal on a positioning scanning path, a force-electricity collaborative sensing strategy is executed, which comprises the following steps: when it is detected that the arc current signal changes from nothing to something or characteristic fluctuation occurs, it is determined that the welding wire touches the edge of a weld; when the arc current signal is not detected but a weld area should exist according to a preset path, the welding gun is controlled to perform a downward pressing action, and after the pressure signal reaches a preset threshold value, the welding gun is switched to forward scanning until the arc current signal is detected again; based on the coordinates of all edge points, the current and the stable section of the pressure signal, the actual spatial position of the weld and the gap width are calculated. Reliable and quantitative measurement of the size of the weld gap is realized.

Description

Technical Field

[0001] This invention relates to the field of automated welding technology, and in particular to a method, system, and storage medium based on welding torch current force control composite positioning sensing. Background Technology

[0002] In automated welding production, due to factors such as workpiece blanking errors, clamping deviations, and thermal deformation during welding, the actual weld position and gap size often differ from the preset welding trajectory. Therefore, before igniting the arc, the welding robot needs to accurately locate the weld and measure its gap in order to adjust the welding trajectory and process parameters. This is crucial for ensuring welding quality and yield.

[0003] Currently, common robotic welding seam positioning methods mainly include vision-based positioning and wire contact positioning. The accuracy of vision-based positioning is easily affected by factors such as workpiece surface reflection, weld type, viewing angle, and welding fumes, and its anti-interference capability is weak. Traditional wire contact positioning relies on the electrical signal feedback generated when the welding wire touches the workpiece. Although its structure is simple and unaffected by arc light interference, it typically only determines whether contact has occurred—a simple switching signal. This single wire contact positioning method cannot sense the magnitude and changes in contact pressure, nor can it measure the weld gap width. Therefore, when facing complex and variable welding conditions, both the accuracy and information richness of positioning are insufficient.

[0004] To address this, invention patent CN115213524B discloses a magnetically controlled TIG arc contact-based dual-sensor fusion weld seam tracking method. This method utilizes a pressure sensor to detect the contact state of the welding wire and combines this with the welding current changes collected by a Hall sensor during the oscillation of the magnetically controlled arc to reconstruct the three-dimensional morphology of the workpiece weld seam, thereby achieving weld seam tracking. This solution combines tactile sensing and arc sensing, to some extent compensating for the limitations of a single sensor.

[0005] However, the aforementioned existing technologies still have the following problems: Firstly, in existing solutions, pressure sensors are mainly used to detect whether the welding wire has contacted the starting point before welding begins. However, during welding tracking, it still essentially relies on the scanning of the magnetically controlled arc and the current feedback when the welding wire touches a short circuit. The pressure sensing and arc sensing are not a deep composite that is synchronous and coordinated in space and time, and they do not constitute a two-way closed-loop search logic based on force perception and guided by electrical signals.

[0006] Secondly, existing solutions focus on using arc oscillation scanning to reconstruct the weld profile for lateral tracking, but do not propose a technical solution for accurately and reliably measuring the weld gap size itself. In actual production, however, changes in weld gap directly affect molten pool behavior and filler volume; therefore, accurate gap measurement is another core requirement for adaptive welding.

[0007] Therefore, how to provide a positioning sensing method that can achieve deeper closed-loop collaboration between force control sensing and arc sensing, and realize accurate measurement of weld gap size while reliably detecting weld position, has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0008] The technical problem to be solved by the present invention is how to achieve closed-loop coordination between force control sensing and arc sensing, so as to accurately detect the weld position and reliably measure the weld gap size.

[0009] In a first aspect, to solve the above-mentioned technical problems, the present invention provides a method for position sensing based on welding torch current force control, comprising the following steps: A force sensor is installed on the welding torch to sense the pressure when the welding torch contacts the workpiece in real time; and the arc current signal output by the welding machine is acquired to detect the electrical contact state between the welding wire and the workpiece in real time. During the positioning and scanning process, the welding torch is moved to keep the welding wire in contact with the workpiece surface, while the pressure signal fed back by the force sensor and the arc current signal are collected. Based on the spatiotemporal composite changes of the pressure signal and the arc current signal along the positioning scanning path, a force-electricity co-sensing strategy is executed to determine the weld position and measure the weld gap size; wherein, the force-electricity co-sensing strategy includes: (a) When the arc current signal is detected to be present from zero or to have a characteristic fluctuation, it is determined that the welding wire has touched the edge of the weld and the current coordinates are recorded as the edge point; (b) In areas where the arc current signal is not detected but a weld should exist according to the preset path, the welding torch is controlled to perform a downward action based on the pressure signal to maintain physical contact between the welding wire and the workpiece, and after the pressure signal reaches the preset threshold, it switches to forward scanning until the arc current signal is detected again. (c) By comprehensively analyzing the coordinates of all edge points recorded on the positioning scanning path and the stable segments of current and pressure signals, the actual spatial position and gap width of the weld are calculated.

[0010] Furthermore, the force-electricity coordinated sensing strategy specifically includes: During the scanning process, if no current is detected between the welding wire and the workpiece, the welding torch is controlled to press down a preset distance, and the pressure signal is monitored at the same time. Once the pressure signal indicates that the welding torch has made contact with the workpiece, the downward pressure is stopped and the torch continues to move forward along the current scanning direction. If the pressure signal is not detected after pressing down to the maximum preset distance, maintain the current depth and continue scanning forward until the pressure signal reappears; After detecting the pressure signal, the welding torch is controlled to move upward until both the pressure signal and the arc current signal disappear, then it is pressed down a preset distance and continues to scan forward.

[0011] Preferably, the preset distance in the controlled downward pressing distance of the welding torch is 0.2-3mm.

[0012] Furthermore, the step of executing a force-electricity collaborative sensing strategy based on the spatiotemporal composite changes of the pressure signal and the arc current signal along the positioning scanning path to determine the weld position and measure the weld gap size includes: The current and pressure data curves throughout the scanning process are collected by the host computer or robot controller; Identify the area with the greatest fluctuations in current and pressure, and determine it as the center area of ​​the weld. On both sides of the central region of the weld, the positions where the current signal changes from fluctuating to stable are identified and determined as the two edges of the weld. Based on the coordinates of the two edges of the weld, the actual position and gap size of the current weld are calculated.

[0013] Furthermore, the positioning scanning process also includes: The weld position coordinates calculated from the initial positioning scan are used as a reference. Perform at least one subsequent positioning scan, compare the weld position coordinates calculated by the subsequent scan with the reference datum, and obtain the position deviation value; The positional deviation value is added to the preset trajectory coordinates of the subsequent actual welding, so that the welding trajectory is adaptively compensated.

[0014] Further, acquiring the arc current signal output by the welding machine includes: During the search phase, the welding machine outputs a voltage of less than 30V and a current of less than 3A to the welding wire to detect the electrical contact status of the workpiece.

[0015] Furthermore, determining the weld location and measuring the weld gap size also includes: Based on the measured weld gap size, welding process parameters that match the current gap width are automatically called to adapt to welding condition fluctuations caused by gap changes.

[0016] Furthermore, controlling the movement of the welding torch during the positioning and scanning process also includes: Preset the search range of the welding torch; During the search process, if the welding torch moves to or beyond the preset search range, the search will stop immediately and return to the starting point to re-execute the positional scan, so as to ensure that valid current and pressure change data are collected.

[0017] A second aspect of the present invention provides a welding torch current force control composite positioning sensing system, comprising: A welding torch is equipped with a force sensor to sense the contact pressure between the tip of the welding torch and the workpiece. The welding machine is electrically connected to the welding torch and outputs its arc current feedback signal in real time. An industrial robot is used to perform the movement of the welding torch; The controller is communicatively connected to the industrial robot, the force sensor, and the welding machine, and is configured to perform the method described.

[0018] A third aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon that, when executed by a controller, performs the steps of the method as described.

[0019] Compared with the prior art, the embodiments of the present invention have the following beneficial effects: Compared to the division of labor in CN115213524B, where force sensing is only used for initial positioning before welding and tracking during welding mainly relies on arc scanning and short-circuit signals, this invention constructs a closed-loop collaborative sensing strategy that integrates force control and arc sensing in real time, interactively, and simultaneously during the positioning and scanning process. By providing a reliable physical contact reference for arc sensing through force feedback, and dynamically adjusting the searching action of the welding torch according to the presence or absence of current and pressure changes, this invention not only accurately identifies the spatial position of the weld but also achieves reliable and quantitative measurement of the weld gap size for the first time. This provides richer and more accurate decision-making basis for subsequent adaptive compensation of welding trajectory and dynamic matching of welding parameters. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a partial structural schematic diagram of the arc welding torch disclosed in an embodiment of the present invention; Figure 2 This is a flowchart disclosed in an embodiment of the present invention.

[0022] In the picture: 100. Welding torch; 101. Force sensor; 102. Collision avoidance sensor. Detailed Implementation

[0023] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] This invention aims to provide a composite positioning and sensing method based on welding torch current force control. This method primarily utilizes the collaborative work of an industrial robot or similar motion mechanism, a pressure sensor, a welding torch, a welding machine, and a host computer or robot controller. Its core lies in constructing a force-electricity collaborative sensing strategy. This strategy combines the contact pressure signal sensed by the force sensor with the arc current signal fed back by the welding machine through spatiotemporal composite analysis and closed-loop utilization during the weld seam positioning and scanning process. This allows for precise determination of the weld seam position while simultaneously achieving quantitative measurement of the weld seam gap size.

[0025] The present invention provides a welding torch current-force control composite positioning sensing method, which mainly includes: setting a force sensor on the welding torch to sense the pressure when the welding torch contacts the workpiece in real time; and acquiring the arc current signal output by the welding machine to detect the electrical contact state between the welding wire and the workpiece in real time; during the positioning scanning process, controlling the movement of the welding torch to keep the welding wire in contact with the workpiece surface, while simultaneously acquiring the pressure signal and arc current signal fed back by the force sensor; and based on the spatiotemporal composite changes of the pressure signal and arc current signal on the positioning scanning path, executing a force-electric collaborative sensing strategy to determine the weld position and measure the weld gap size.

[0026] Among them, the force-electricity coordinated sensing strategy includes: (a) When the arc current signal is detected to be present or to fluctuate characteristically, it is determined that the welding wire has touched the edge of the weld and the current coordinates are recorded as the edge point.

[0027] (b) In areas where no arc current signal is detected but a weld should exist according to the preset path, the welding torch is controlled to perform a downward action based on the pressure signal to maintain physical contact between the welding wire and the workpiece, and after the pressure signal reaches the preset threshold, it switches to forward scanning until the arc current signal is detected again.

[0028] (c) By comprehensively analyzing the coordinates of all edge points recorded on the positioning scanning path and the stable segments of current and pressure signals, the actual spatial position and gap width of the weld are calculated.

[0029] The following is combined Figure 2 The flowchart shown illustrates the specific steps of the method provided by this invention.

[0030] Step 1: Initialization and Search Preparation Before initiating the positioning task, the host computer or robot controller first sets the search range of the welding torch. This search range is a spatial area surrounding a preset weld start point, and its dimensions are set based on the workpiece clamping tolerances and the estimated deviation of the weld position. For example, it could be a rectangular area with a length and width of 10-20 mm and a height of 5-10 mm. The purpose of setting the search range is to prevent the welding torch from performing invalid searches in areas without workpieces and to be associated with subsequent out-of-range protection logic.

[0031] Simultaneously, the host computer or robot controller sends a command to the welding machine via the communication interface to switch the welding machine's output mode to a low-voltage, low-current search mode. In this mode, the voltage output by the welding machine to the welding wire is below 30V, and the current is below 3A. The specific voltage and current settings are selected based on the welding wire diameter and workpiece material to reliably detect the electrical contact status of the workpiece without damaging the workpiece surface or causing accidental arcing. Welding shielding gas is also not supplied to the welding torch during this stage.

[0032] Step 2, Initial Contact and Probe The host computer or robot controller controls the robot to quickly move the welding torch to a safe height above the preset search range, and then controls the welding torch to descend towards the workpiece. During this process, the arc current signal fed back by the welding machine and the pressure signal fed back by the force sensor are monitored in real time.

[0033] Since factors such as oil stains and rust on the workpiece surface may cause a large initial contact resistance, the generation of current signals may be delayed or unstable. Therefore, this embodiment adopts a strategy of using force signals as the main basis for initial contact confirmation and current signals as auxiliary verification.

[0034] Once initial contact is confirmed, the host computer controls the welding torch to stop descending and raise it a short distance. In one specific embodiment, the raising is 1-3 mm to establish a small gap between the welding wire tip and the workpiece surface. This raising action serves two purposes: firstly, to prevent the welding torch from rigidly scraping against the workpiece during subsequent lateral scanning motion, protecting the force sensor and the welding torch end effector; secondly, to provide a clear zero-pressure reference for the force sensor mounted on the welding torch, facilitating a clear distinction between non-contact and contact states during subsequent searches.

[0035] Step 3: Force-Electric Coordinated Search and Weld Edge Detection After initial contact and exploration, the core force-electric collaborative search phase begins. The host computer controls the robot to move the welding torch at a preset constant speed along a transverse path roughly perpendicular to the estimated weld extension direction. The scanning speed is set based on the estimated weld gap size and the system response speed, typically 3-10 mm / s.

[0036] Throughout the scanning process, the host computer synchronously acquires the analog pressure signal output by the force sensor and the analog arc current signal output by the welding machine at a fixed sampling period. In the control logic of this embodiment, these two signals are given equal importance and are processed jointly to adjust the motion state of the welding torch in real time, rather than simply using one signal as a switching trigger. This mechanism is the core of the force-electricity collaborative sensing strategy, and its specific manifestations include closed-loop processing in the following typical cases: Scenario 1: Arc current signal from zero to present. As the welding wire scans along the workpiece surface, when the tip of the wire touches the first edge of the weld, electrical contact is formed between the wire and the workpiece. The arc current signal changes from a state of no current or a weak induced current to a reliably detectable low current state. The host computer detects this current signal change in real time, and simultaneously, combined with any slight pressure fluctuations that may occur at this location from the force sensor, determines that the current coordinate position is a weld edge point on one side, and records and stores this spatial coordinate value.

[0037] Scenario 2: Disappearance of Arc Current Signal. As the welding torch continues to move forward, when the tip of the welding wire leaves the first edge of the weld and enters the weld gap region, the electrical contact between the welding wire and the workpiece breaks, and the arc current signal disappears. The welding wire is suspended in the gap, and the pressure signal fed back by the force sensor also returns to zero. Based on this, the host computer determines that the welding wire has left the workpiece and entered the weld gap region, and records the spatial coordinates of the position where the current signal disappears as a reference check point for the position of the first side edge.

[0038] Scenario 3: No current and no pressure within the gap. After entering the weld gap, the welding wire cannot contact the workpiece, therefore there is neither an arc current signal nor a force sensor pressure signal. In this case, the host computer initiates the active pressure-down search mechanism in the force-electricity collaborative sensing strategy. The host computer controls the welding torch to perform the first pressure-down action towards the workpiece, with a pressure distance in small increments, such as 0.2-1mm. After each increment, the pressure signal fed back by the force sensor is quickly checked.

[0039] Scenario 4: Pressure signal appears after pressing down, but no current signal. When the welding torch is pressed down by a certain increment, the pressure value detected by the force sensor exceeds the preset pressure judgment threshold, indicating that the tip of the welding wire has touched the workpiece surface at the bottom of the gap or the root of the workpiece edge on the other side of the gap. However, at this time, because the contact point may be covered by an oxide layer or impurities, the arc current signal has not yet been generated or the signal is extremely weak and unstable. Based on the recovery of the force signal, the host computer judges that physical contact has been established, so it stops pressing down and instead controls the welding torch to continue scanning forward at the current contact pressure state.

[0040] Scenario 5: Handling the situation when there is still no stable current after pressure is applied. As a continuation of Scenario 4, the welding torch relies on pressure feedback from the force sensor to maintain contact with the workpiece and move forward. During this movement, the friction and slight squeezing between the welding wire tip and the workpiece surface may gradually damage and remove the non-conductive layer at the contact point. When the welding wire crosses the bottom of the gap and reaches the other edge of the weld, or when good electrical contact is formed with the workpiece due to the removal of the non-conductive layer, the arc current signal changes from weak to stable. After detecting this rising edge transition of the current signal, the host computer, combined with the currently stable pressure signal from the force sensor, comprehensively determines that the other edge point of the weld has been detected and records and stores its spatial coordinates.

[0041] Scenario 6: No pressure signal after pressing down to the maximum distance. If the cumulative pressing distance has reached the preset maximum allowable pressing distance after the pressing action is performed. In one specific embodiment, the maximum pressing distance is set to 3mm, but the force sensor still does not detect a valid pressure signal, this indicates that the gap depth at the current position is greater than the preset maximum pressing amount. At this time, the host computer will not continue to press down to avoid the welding torch colliding with the workpiece or causing an overload impact on the force sensor. The host computer controls the welding torch to maintain at the maximum pressing depth position and continue to move forward along the original scanning direction until the pressure signal from the force sensor appears, and then proceed with subsequent processing according to the logic of Scenario 4 and Scenario 5.

[0042] The processing flow from scenario one to scenario six described above constitutes a complete closed-loop decision chain for the force-electricity collaborative sensing strategy. It can be seen that in this strategy, the force signal is not merely a switch indicator indicating the presence or absence of contact, but serves as a real-time feedback basis for generating continuous motion commands such as pressing down, maintaining, and lifting. Similarly, the current signal is not simply a switch catalyst for detecting edge points; its presence, stability, and fluctuation characteristics, along with the correspondence between the force signal and the force signal on the time and space axes, are analyzed holistically to ultimately determine the precise positions of the weld edges on both sides.

[0043] Step 4: Calculation and location determination of weld gap size After completing a full transverse scan path, the host computer obtains a series of discrete sampling data points along the scan path, containing spatial coordinates, pressure values, and current values. The host computer performs post-processing analysis on these data to extract key geometric information of the weld.

[0044] Specific data processing and analysis logic combined Figure 1 and Figure 2 Please provide an explanation. Figure 1 and Figure 2 Schematic diagrams of the welding torch scanning laterally above the weld are shown from different perspectives. In the diagrams, the welding torch moves laterally, with the tip of the welding wire passing sequentially through the base material area on the left side of the workpiece, the weld gap area, and the base material area on the right side of the workpiece.

[0045] The host computer first identifies key points where signal characteristics change on the current data curve. The first rising edge position where the current jumps from a stable low level or zero value to a higher level, and the last falling edge position where the current drops from a higher level to a stable low level or zero value, correspond to two transition points on the scanning path where the welding wire enters and leaves the workpiece contact area. These two positions are initially designated as candidate points for the left and right edges of the weld.

[0046] Then, the host computer performs a joint analysis of the pressure and current data curves, aligning them along the time axis. In areas of significant current signal fluctuation, it checks whether the corresponding pressure signal also exhibits characteristic fluctuations or troughs to rule out false jumps in the current signal caused by surface impurities or accidental poor contact. Simultaneously, on both sides of the current signal fluctuation area, sections where the current signal stabilizes and the pressure signal also becomes relatively stable are identified. The boundary between these two stable sections and the fluctuation sections is ultimately determined as the actual edges of the weld.

[0047] Based on the above analysis logic, the host computer calculates the exact spatial coordinates of the left and right edges of the weld. The difference in lateral distance between the two edges is the measured value of the weld gap size at the current scanning position. Simultaneously, the coordinates of the weld center are calculated from the midpoint of the coordinates of the two edges, used to characterize the actual spatial position of the entire weld.

[0048] Step 5: Initial baseline establishment and subsequent deviation comparison In actual production, a workpiece typically contains multiple welds that require welding, or the same weld may vary in position on different workpieces produced in a batch due to material cutting and clamping deviations. To address this issue, the method in this embodiment also includes an application mechanism for establishing an initial scanning reference and comparing subsequent deviations.

[0049] When locating the first weld or the first workpiece, the calculation results from steps one to four above are set as the reference weld position coordinates and reference gap size values, and stored in the non-volatile memory of the host computer.

[0050] When locating subsequent welds or workpieces, the same scanning path planning and force-electric collaborative sensing strategy as the initial scan are executed, and the current weld's position coordinates and gap size are calculated. The host computer subtracts the currently calculated weld position coordinates from the stored reference weld position coordinates to obtain the position deviation values ​​in each direction. This position deviation value reflects the spatial offset of the subsequent weld relative to the initial reference weld.

[0051] During actual welding operations, the host computer appends the aforementioned positional deviation values ​​to the pre-programmed standard welding trajectory coordinates, generating a corrected welding trajectory instruction which is then sent to the robot for execution, thereby achieving adaptive compensation of the welding trajectory. Similarly, the deviation between the currently calculated gap size and the reference gap size can also be used to dynamically adjust welding parameters such as wire feed speed, welding current, or oscillation amplitude during the welding process to adapt to fluctuations in welding conditions caused by changes in gap.

[0052] Step 6: Out-of-range protection and retry mechanism To improve the robustness and safety of the positioning process, an out-of-range protection and retry mechanism are implemented during the scanning process. During the collaborative search in steps 2 and 3, the host computer continuously monitors the real-time position coordinates of the welding torch. If the welding torch's movement distance exceeds the preset search range boundary during the horizontal scan or vertical depth search, the host computer immediately terminates the current positioning action, stops the welding torch's movement, and issues an out-of-range alarm.

[0053] Subsequently, the host computer controls the welding torch to automatically return to the starting point of the search range and restart the initial contact confirmation in step 2 and the force-electrical coordinated search in step 3. The number of retry cycles can be preset, for example, to be repeated one or two times. If a valid positioning signal cannot be obtained within the search range within the preset number of retry cycles, the host computer will ultimately determine that the current positioning has failed and stop the machine, awaiting manual intervention. This mechanism effectively prevents collision damage between the welding torch and the workpiece or tooling caused by severe workpiece misalignment, positioning fixture malfunction, or program errors.

[0054] Step 7, Welding execution Once the weld position and gap size are successfully calculated, and subsequent deviation compensation values ​​are generated, the host computer controls the robot to move the welding torch to the corrected welding starting point. The host computer then controls the welding machine via the communication interface to return to the set normal welding output mode, inputting the predetermined welding current and voltage parameters, opening the welding shielding gas channel, and igniting the welding arc. The welding process proceeds according to the corrected trajectory until the current weld seam is completely deposited.

[0055] The present invention also provides a welding torch current force control composite positioning sensing system, which mainly includes a welding torch, a welding machine, a controller, and an industrial robot that performs the movement of the welding torch.

[0056] Among them, such as Figure 1 The diagram shows a partial structural schematic of an arc welding torch in a specific embodiment. It includes a welding torch 100. A force sensor 101 is positioned between the industrial robot's end flange and the welding torch 100 to sense the contact pressure between the welding torch and the workpiece in real time during the positioning and scanning process, providing continuous pressure feedback signals for the force-electric collaborative sensing strategy. An anti-collision sensor 102 is also positioned near the end effector of the welding torch as an additional safety protection device. When the welding torch experiences an accidental collision during positioning or welding motion and exceeds a preset load threshold, the anti-collision sensor 102 can promptly trigger an emergency stop or retraction signal. Together with the force sensor 101, it constitutes a graded protection mechanism from precise force sensing to overload safety protection.

[0057] In one specific embodiment, welding wire is threaded inside the welding torch 100, which is electrically connected to the welding machine via a welding cable and outputs its arc current feedback signal in real time. The workpiece is fixed on the welding fixture and forms an electrical connection with the welding machine as the other end of the arc circuit. The controller is communicatively connected to the industrial robot, force sensor, and welding machine, and is configured to perform the above-described method.

[0058] In addition, the present invention also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a controller, implements the steps of the above-described method.

[0059] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for position sensing based on welding torch current force control, characterized in that, Includes the following steps: A force sensor is installed on the welding torch to sense the pressure when the welding torch contacts the workpiece in real time; and the arc current signal output by the welding machine is acquired to detect the electrical contact state between the welding wire and the workpiece in real time. During the positioning and scanning process, the welding torch is moved to keep the welding wire in contact with the workpiece surface, while the pressure signal fed back by the force sensor and the arc current signal are collected. Based on the spatiotemporal composite changes of the pressure signal and the arc current signal along the positioning scanning path, a force-electricity co-sensing strategy is executed to determine the weld position and measure the weld gap size; wherein, the force-electricity co-sensing strategy includes: (a) When the arc current signal is detected to be present from zero or to have a characteristic fluctuation, it is determined that the welding wire has touched the edge of the weld and the current coordinates are recorded as the edge point; (b) In areas where the arc current signal is not detected but a weld should exist according to the preset path, the welding torch is controlled to perform a downward action based on the pressure signal to maintain physical contact between the welding wire and the workpiece, and after the pressure signal reaches the preset threshold, it switches to forward scanning until the arc current signal is detected again. (c) By comprehensively analyzing the coordinates of all edge points recorded on the positioning scanning path and the stable segments of current and pressure signals, the actual spatial position and gap width of the weld are calculated.

2. The method for composite positioning sensing based on welding torch current force control according to claim 1, characterized in that, The force-electricity coordinated sensing strategy specifically includes: During the scanning process, if no current is detected between the welding wire and the workpiece, the welding torch is controlled to press down a preset distance, and the pressure signal is monitored at the same time. Once the pressure signal indicates that the welding torch has made contact with the workpiece, the downward pressure is stopped and the torch continues to move forward along the current scanning direction. If the pressure signal is not detected after pressing down to the maximum preset distance, maintain the current depth and continue scanning forward until the pressure signal reappears; After detecting the pressure signal, the welding torch is controlled to move upward until both the pressure signal and the arc current signal disappear, then it is pressed down a preset distance and continues to scan forward.

3. The welding torch current force control-based composite positioning sensing method according to claim 2, characterized in that, The preset distance in the control of the welding torch pressing down a preset distance is 0.2-3mm.

4. The method for composite positioning sensing based on welding torch current force control according to claim 1, characterized in that, The method of executing a force-electricity collaborative sensing strategy based on the spatiotemporal composite changes of the pressure signal and the arc current signal along the positioning scanning path to determine the weld position and measure the weld gap size includes: The current and pressure data curves throughout the scanning process are collected by the host computer or robot controller; Identify the area with the greatest fluctuations in current and pressure, and determine it as the center area of ​​the weld. On both sides of the central region of the weld, the positions where the current signal changes from fluctuating to stable are identified and determined as the two edges of the weld. Based on the coordinates of the two edges of the weld, the actual position and gap size of the current weld are calculated.

5. The method for composite positioning sensing based on welding torch current force control according to claim 1, characterized in that, The positioning scanning process also includes: The weld position coordinates calculated from the initial positioning scan are used as a reference. Perform at least one subsequent positioning scan, compare the weld position coordinates calculated by the subsequent scan with the reference datum, and obtain the position deviation value; The positional deviation value is added to the preset trajectory coordinates of the subsequent actual welding, so that the welding trajectory is adaptively compensated.

6. The method for composite positioning sensing based on welding torch current force control according to claim 1, characterized in that, The acquisition of the arc current signal output by the welding machine includes: During the search phase, the welding machine outputs a voltage of less than 30V and a current of less than 3A to the welding wire to detect the electrical contact status of the workpiece.

7. The method for composite positioning sensing based on welding torch current force control according to claim 1, characterized in that, The process of determining the weld location and measuring the weld gap also includes: Based on the measured weld gap size, welding process parameters that match the current gap width are automatically called to adapt to welding condition fluctuations caused by gap changes.

8. The welding torch current force control-based composite positioning sensing method according to claim 1, characterized in that, The method of controlling the movement of the welding torch during the positioning and scanning process also includes: Preset the search range of the welding torch; During the search process, if the welding torch moves to or beyond the preset search range, the search will stop immediately and the torch will return to the starting point to re-execute the positional scan, so as to ensure that valid current and pressure change data are collected.

9. A welding torch current force control composite positioning sensing system, characterized in that, include: A welding torch is equipped with a force sensor to sense the contact pressure between the tip of the welding torch and the workpiece. The welding machine is electrically connected to the welding torch and outputs its arc current feedback signal in real time. An industrial robot is used to perform the movement of the welding torch; A controller is communicatively connected to the industrial robot, the force sensor, and the welding machine, and the controller is configured to perform the method as described in any one of claims 1-8.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by the controller, the program implements the steps of the method as described in any one of claims 1-8.

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