WO2017175541A1 - アーク倣い溶接方法およびアーク倣い溶接装置 - Google Patents
アーク倣い溶接方法およびアーク倣い溶接装置 Download PDFInfo
- Publication number
- WO2017175541A1 WO2017175541A1 PCT/JP2017/009826 JP2017009826W WO2017175541A1 WO 2017175541 A1 WO2017175541 A1 WO 2017175541A1 JP 2017009826 W JP2017009826 W JP 2017009826W WO 2017175541 A1 WO2017175541 A1 WO 2017175541A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- welding
- current
- arc
- voltage
- resistance value
- Prior art date
Links
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K9/00—Arc welding or cutting
- B23K9/12—Automatic feeding or moving of electrodes or work for spot or seam welding or cutting
- B23K9/127—Means for tracking lines during arc welding or cutting
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K9/00—Arc welding or cutting
- B23K9/12—Automatic feeding or moving of electrodes or work for spot or seam welding or cutting
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K9/00—Arc welding or cutting
- B23K9/02—Seam welding; Backing means; Inserts
- B23K9/0216—Seam profiling, e.g. weaving, multilayer
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K9/00—Arc welding or cutting
- B23K9/09—Arrangements or circuits for arc welding with pulsed current or voltage
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K9/00—Arc welding or cutting
- B23K9/095—Monitoring or automatic control of welding parameters
- B23K9/0956—Monitoring or automatic control of welding parameters using sensing means, e.g. optical
Definitions
- the present invention relates to an arc copy welding method and an arc copy welding apparatus.
- arc welding In arc welding, the amount of deviation between the joint position to be welded and the wire tip position is detected based on electrical changes such as welding current and welding voltage, and the welding line is automatically followed by correcting this deviation. “Arc copying” is widely used. This arc copying prevents welding defects by detecting and correcting deviations in the target position of the work tool (welding torch) caused by installation error, machining error, deformation during machining, etc. It aims to improve.
- the principle of such arc scanning utilizes the fact that the welding current or the welding voltage changes in accordance with the change in the protruding length of the welding wire (more precisely, the distance La from the torch power supply point to the base metal). is doing. That is, the deviation of the target position of the torch is detected from the asymmetry of the arc current waveform or the arc voltage waveform during the weaving operation. The detected deviation is fed back to the automatic welding apparatus or welding robot system to correct the deviation of the torch tip position. This automatically follows the weld line.
- Patent Document 1 As such arc scanning control, there is a “method of setting a scanning parameter of a robot arc sensor and a method of setting a scanning parameter of a robot arc sensor” disclosed in Patent Document 1.
- Patent Document 1 when the welding torch is moved while being welded along a teaching line divided by a plurality of sections having different shift amounts, the welding torch is shifted according to the shift amount determined for each section.
- a moving step for moving the sample, an averaging step for averaging the quantity of electricity supplied and sampled to the welding torch moving for each section at a predetermined cycle longer than the sampling cycle, and the averaging A difference value calculating step of calculating a difference value between the value and the reference value, an average difference value calculating step of calculating an average difference value of the difference values for each section, and an average difference value of the difference values for each section
- a regression line and a correlation coefficient obtaining step for obtaining a correlation coefficient between the regression line and the average difference value based on the regression line, and a parameter relating to the tracing related to the slope and intercept of the regression line Evaluated on the basis of the serial correlation coefficient discloses a method of setting the copying parameters arc sensor robot, characterized in comprising an evaluation step of setting the parameter as copying parameters.
- arc tracing is feedback control that corrects the position of the torch tip movement locus at a right angle to the welding line in accordance with the amount of change in the welding current or welding voltage.
- various problems have occurred when applied to actual welding sites. That is, according to the arc copy welding technique used conventionally, -Just looking at the difference in welding current value between the left and right ends of the joint position (groove), the S / N ratio is poor, and further higher accuracy is required. -Further precision is required when the weaving amplitude is small relative to the leg length of the welding wire, or when the thickness of the plate to be welded is thin.
- -Arc copying by simple resistance value detection cannot detect a significant change in resistance value due to the influence of the control loop.
- the present invention has been made in view of the above-described problems, and an object of the present invention is to provide a technique that enables accurate arc copy welding at a welding site.
- the arc scanning welding method of the present invention is an arc scanning welding method in a consumable electrode type welding apparatus having a weaving function of swinging the torch with respect to the welding direction, the welding current supplied to the consumable electrode and
- the welding voltage includes a high frequency component having a frequency higher than the frequency of the weaving, the welding current and the welding voltage during the welding are detected, and a resistance value is obtained from the detected welding current and the welding voltage.
- a deviation from the welding line of the torch is detected from the obtained resistance value and the information on the both ends of the amplitude of the weaving.
- the high frequency component is larger than the direct current component of the welding current or welding voltage supplied to the consumable electrode.
- the frequency of the high frequency component is 100 Hz or more.
- the welding current and welding voltage supplied to the consumable electrode may be a pulse waveform, and a high frequency component included in the pulse waveform may be used as the high frequency component.
- the arc copying welding apparatus of the present invention employs the following technical means. That is, the arc copying welding apparatus of the present invention is a consumable electrode type arc copying welding apparatus having a weaving function for swinging the torch with respect to the welding direction and an arc copying function, wherein a welding current and A welding power source configured to supply a welding voltage and include a high-frequency component having a frequency higher than the frequency of the weaving in the welding current and the welding voltage; and a current detector that detects the welding current during welding; A voltage detector for detecting a welding voltage during welding, and a deviation detector for detecting a deviation from a welding line of the torch, wherein the deviation detector includes the current and the voltage detected by the current detector.
- the resistance value is obtained from the welding current and welding voltage during welding from the voltage detected by the detector, and the obtained resistance value and the amplitude both ends of the weaving Detecting a deviation from the weld line of the torch from the information about the location.
- the first embodiment of the present invention it is a graph showing the results when the resistance value R, the inductance L, and the offset voltage Vo are estimated from the current / voltage waveform on which the high frequency is superimposed. It is the graph which showed the electric current difference in the right-and-left end of a joint position in the comparative example using the high frequency removal filter in order to suppress the fluctuation
- FIG. 1 is a configuration diagram of a copying system using a welding robot 5.
- the vertical articulated robot system includes a welding robot 5 and a control device 6 having a teaching pendant (not shown).
- the welding robot 5 is a vertical articulated 6-axis industrial robot, and a welding tool including a welding torch 1 and the like is provided at the tip thereof.
- the welding robot 5 may be mounted on a slider that moves itself.
- the control device 6 controls the welding robot 5 according to a program taught in advance.
- This program may be created using a teaching pendant connected to the control device 6 or an offline teaching system using a personal computer. In any case, this program is created in advance before the actual operation.
- the program created by the personal computer is transferred to the control device 6 via a storage medium or the like, or transferred to the control device 6 by data communication.
- the arc copying welding method according to the present embodiment is realized as a program provided in the control device 6.
- FIG. 2 shows a schematic diagram of arc welding.
- arc welding a voltage is applied between the welding wire 3 (consumable electrode) supplied from the welding torch 1 and the base material 4 by the welding power source 2 to generate an arc between the welding wire 3 and the base material 4.
- the base metal 4 and the welding wire 3 are welded while being melted by the arc heat. Since the welding wire 3 melts away with arc welding, the welding wire 3 continues to be supplied via the inside of the welding torch 1 by the feeding device during welding. That is, this arc welding is consumable electrode type welding.
- the weld metal in which the base material 4 and the welding wire 3 are melted is solidified to form a weld bead, thereby realizing strong welding.
- medium thickness plate welding represented by welding of thick steel plates
- the control device 6 outputs a command to perform the weaving operation of the welding torch 1 to the welding robot 5 (see FIG. 1).
- the welding power source 2 can output an arbitrary voltage waveform programmed in advance. For example, it is possible to output a waveform with a predetermined frequency superimposed thereon or a pulse waveform with a predetermined frequency.
- the welding power source 2 incorporates a voltage detector and a current detector (both not shown), and can measure the actually output voltage and current (ie, welding voltage and welding current).
- a welding gas is also supplied from the welding torch 1 to protect the arc column from the atmosphere.
- the molten metal after melting is also protected from the atmosphere by the gas generated by the decomposition of the flux contained in the welding wire 3, and suppresses welding defects such as blow holes.
- the processing accuracy due to gas cutting or bending of the welded workpiece is poor, the welded workpiece cannot be corrected with the jig, and the installation accuracy may be poor.
- the weld line which is the position to be welded, is not always at a predetermined position due to the fact that it cannot be restrained and may be deformed by thermal strain. Weld line misalignment generally occurs on the order of several millimeters to centimeters.
- the deviation from the welding line allowed for the arc welding robot in the thick plate field is generally less than 1 mm, and it cannot be welded by a playback type robot operating at a predetermined position. That is, in the welding robot for medium-thick plates, the deviation between the welding position taught in advance and the welding position of the actual workpiece is detected in real time by the deviation detector, and the welding line is adapted to this each time with a precision of sub mm order. It is an essential condition and is one of the very important functions that are indispensable.
- FIG. 3A and 3B are explanatory diagrams schematically showing the principle of arc scanning.
- the distance between the welding torch 1 and the base material 4 (hereinafter referred to as “torch height”) varies depending on the weaving position.
- the welding current also changes depending on the weaving position as the torch height changes.
- a welding voltage also changes with a weaving position with the change of torch height.
- the welding current changes symmetrically with respect to the weaving center B in the figure, and the welding currents at both ends of the weaving amplitude (weaving end points) A and C coincide.
- the state in which the welding currents at the weaving end points A and C coincide with each other is a normal state.
- FIG. 4 shows the current waveform at the time of using the constant voltage welding power supply 2 used for arc welding.
- FIG. 4 shows the waveform of the welding current when the weaving center is deliberately shifted by 2 mm from the weld line and the weaving operation is performed with a 1-second period and an amplitude of 2 mm. Since the weaving center is always shifted by 2 mm, the welding current difference at the left and right ends is theoretically constant. However, as shown in FIG. 4, the current fluctuation in the entire current waveform is larger than the current difference at the left and right ends, and the current value changes greatly only by a slight shift in the left and right end phases. It can be seen that the ratio to noise is very bad.
- FIG. 5 shows the result of estimating the resistance value R obtained by the following equation (1) using the voltage information V in addition to the same current information I as in FIG. 4 using the constant voltage welding power source 2.
- FIG. 5 is a graph showing the estimation result of the resistance value in the current / voltage waveform in the conventional constant voltage power source. According to the figure, the resistance value fluctuates greatly and no significant information is included. Theoretically, the difference between the resistance values at the left and right ends should be constant if the amount of deviation is constant, but in FIG. 5, the variation in the difference between the resistance values at the left and right ends is large. Thus, it can be seen from FIG. 5 that no weld line deviation can be detected.
- the average resistance value that should have a positive value is negative. This is because, in order to increase the welding stability of the welding power source 2, negative feedback control is performed to decrease the voltage value when the current value increases as shown in FIG. Since this negative feedback acts negatively when converted to a resistance value, the resistance value is negative. As described above, even if the resistance value is simply estimated based on the equation (1) with respect to the current waveform of the normal welding power source 2, only the influence of the control loop is detected, and the difference between the resistance values at the left and right ends is detected. Cannot be detected significantly.
- the following problems occur. -Just looking at the difference in welding current value between the left and right ends of the joint position, the S / N ratio is poor, and further high accuracy is required. -When the weaving amplitude is particularly small with respect to the leg length of the welding wire 3 or when the plate thickness is thin, it is necessary to further increase the accuracy. -Arc copying by simple resistance value detection cannot detect a significant change in resistance value due to the influence of the control loop.
- a deviation amount detection method using the following method is employed to enable accurate arc copy welding at a welding site.
- the basis of this technology is that the welding current and welding voltage supplied to the consumable electrode contain high-frequency components, and the resistance value change accompanying the height fluctuation of the electrode is detected from the welding current and welding voltage during welding, and detected.
- the deviation of the weld line is detected from the change amount of the resistance value and the left and right positions of the weaving.
- the welding power source 2 is controlled so that the welding current or the welding voltage includes a frequency component higher than the weaving cycle. Furthermore, the detection accuracy of the resistance value change is improved by making the high frequency component higher than the direct current component of the welding current or welding voltage.
- the voltage or current command value to the welding power source 2 may include the high frequency component.
- a pulse waveform may be adopted as the welding current and welding voltage supplied to the consumable electrode, and a high frequency component included in the pulse waveform may be used as the high frequency component.
- the frequency of the high frequency component is preferably 100 Hz or more.
- the estimated R, L, and Vo are estimated values averaged in the interval from t 1 to t n , and the frequency range to be smoothed or passed by changing the average interval 1 to n Can be changed.
- n should be selected so that the superimposed high-frequency waveform can pass.
- the above is a method of performing the one-shot type least square estimation every time, but a sequential least square method can be used.
- the one-shot type it can be estimated without being influenced by the past before t 1 , but the calculation amount becomes large.
- the method of least squares has a merit that the amount of calculation can be very small, although the influence of the past is slightly dragged.
- the estimation by the successive least squares method is given by the following equation (5).
- Pi is an estimated value of [R, L, Vo] T in the i-th sequential calculation.
- a (i, :) is a vector in the i-th row of the A matrix, and similarly B (i, :) is a vector in the i-th row of the B matrix.
- ⁇ is a forgetting factor.
- FIG. 8 shows the result of estimation by the above-mentioned successive least square method (given forgetting factor is approximately 0.1 seconds).
- FIG. 10 is an enlarged view of FIG. 8, and FIG. 15 is an enlarged view of FIG. Comparing FIG. 15 (estimating only R) and FIG. 10 (estimating R, L, and Vo), it can be clearly seen that FIG. 10 has less noise.
- the resistance value R is estimated from the current / voltage waveform without applying a filter that removes the superimposed high frequency component.
- the resistance value estimated in this way it is possible to realize an improvement in the SN ratio by detecting a deviation from the weld line from the difference in resistance value at the left and right ends.
- it is necessary is just to obtain
- FIG. 9 the result of looking at the current difference at the left and right end points of the weld line is shown in FIG.
- the current waveform shown in FIG. 9 is obtained by performing a filtering process for cutting a high frequency component on the same current waveform used for obtaining the resistance value of FIG. This is because the high frequency component acts only with noise. Further, the phase difference between the end points by the filter is corrected, and the current difference at the end points is compared.
- FIG. 11 is an enlarged view of FIG.
- the current value variation at other locations is large with respect to the current difference at the left and right end points, and there are locations where the current difference at the end points cannot be obtained significantly.
- FIG. 10 is an enlarged view of FIG. 8 showing the present embodiment. Compared with FIG. 11, in FIG. 10, the change in resistance value at the end point is large, and it can be seen that the deviation of the weld line can be detected with high sensitivity. Further, if the current value is detected while leaving the high frequency component, the current at the end point varies greatly due to the influence of the high frequency as shown in FIG. Even if the time position is slightly shifted, the current value fluctuates. Therefore, the current values at the left and right ends cannot be recognized correctly.
- the current difference at the end point as shown in FIG. 9 is obtained by using a current waveform that has been subjected to filter processing that significantly cuts high frequency components as shown in FIG. Can be detected.
- the high-frequency component is only noise and can only be removed, but in the method of the present embodiment, the resistance value R is estimated by actively utilizing the high-frequency component. Made it possible to do.
- a high frequency component is superimposed on a constant current, but in the second embodiment, a pulse waveform is adopted as an output current waveform from the welding power source 2, and instead of additionally superimposing a high frequency component, a pulse waveform is used.
- the high frequency component of was decided to be used.
- FIG. 12 shows the result of back-calculating V with the estimated values of [R, L, Vo] T estimated by the successive estimation of Equation (5) under such circumstances.
- the actual voltage also changes greatly while including a high frequency component, and the voltage can be estimated with high accuracy by estimating the actual voltage with [R, L, Vo] T.
- R can be estimated in the same manner as the estimated values of [R, L, Vo] T by the estimation based on the equation (1) using only the resistance value.
- the first and second embodiments focus only on the difference between the estimated resistance value R at the left and right ends, but use information other than the value at the left and right ends of the resistance value R, such as taking an average value near the left and right ends. By doing so, it is further resistant to noise and a high S / N ratio can be realized.
- a conventional technique for welding current shows a copying method using a neural network that inputs a welding current waveform. For example, instead of a welding current waveform, a resistance value is shown. By constructing a neural network based on the waveform of R, it is possible to realize copying with higher accuracy than the welding current.
- both the estimation based on the formula (1) (only R) and the estimation based on the formula (2) (R, L, Vo) require a high frequency component that exceeds the control band of the welding power source 2.
- the current and voltage values taken into the robot controller are noise-removed (high-frequency components are removed) by a low-pass filter, they are controlled to have the constant voltage characteristics shown in FIG. Then, it is difficult to estimate R.
- the robot controller 6 samples the welding current and voltage from the welding power source 2.
- the sampling cycle is as low as several ms to several tens of ms, and does not require a sufficiently short sampling cycle with respect to the frequency of the pulse waveform output from the welding power source 2.
- the calculation (including resistance value estimation) necessary for copying is performed by the robot control device 6, but the resistance value estimation according to the present embodiment is performed by an arithmetic device provided in the welding power source 2. Good. This may be performed by estimating only the equation (1), that is, R, and is an especially important matter when the equation (2), that is, L is entered.
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Plasma & Fusion (AREA)
- Mechanical Engineering (AREA)
- Butt Welding And Welding Of Specific Article (AREA)
- Arc Welding In General (AREA)
- Arc Welding Control (AREA)
Abstract
Description
特許文献1は、シフト量が異なる複数の区間で区切られた教示線上に沿って溶接トーチを溶接させながら移動させる際、前記区間毎に定められているシフト量に応じて前記溶接トーチをシフトさせて移動させる移動工程と、前記区間毎に移動中の溶接トーチに供給されてサンプリングされた電気量を、該サンプリングする周期よりも長い所定周期毎に平均化する平均化工程と、該平均化した値と基準値との差分値を算出する差分値算出工程と、前記区間毎の前記差分値の平均差分値を算出する平均差分値算出工程と、前記区間毎の前記差分値の平均差分値に基づいて回帰直線および該回帰直線と前記平均差分値との相関係数を求める回帰直線および相関係数取得工程と、前記回帰直線の傾き、および切片に関係する倣いに関するパラメータを前記相関係数に基づいて評価して、該パラメータを倣いパラメータとして設定する評価工程を含むことを特徴とするロボット用アークセンサの倣いパラメータの設定方法を開示する。
すなわち、従来から用いられているアーク倣い溶接の技術によれば、
・継手位置(開先)の左右端による溶接電流値の差異を見るだけではSN比が悪く、更なる高精度化が必要である。
・溶接ワイヤの脚長に対して特にウィービング振幅が小さい場合、また溶接対象の板厚が薄い場合などでは更なる高精度化が必要となる。
・単純な抵抗値検出によるアーク倣いは、制御ループの影響を受けるなど、有意な抵抗値変化を捉えられない。
即ち、本発明のアーク倣い溶接方法は、溶接方向に対してトーチを揺動させるウィービング機能を備えた消耗電極型の溶接装置におけるアーク倣い溶接方法であって、前記消耗電極へ供給する溶接電流及び溶接電圧に、前記ウィービングの周波数よりも高い周波数の高周波成分が含まれるようにし、溶接中における前記溶接電流及び溶接電圧を検出し、検出された前記溶接電流及び溶接電圧から抵抗値を求め、求められた前記抵抗値と前記ウィービングの振幅両端位置に関する情報とから、前記トーチの溶接線からのズレを検出する。
前記消耗電極へ供給する前記溶接電流及び溶接電圧をパルス波形とし、前記パルス波形に含まれる高周波成分を前記高周波成分として使用することもできる。
即ち、本発明のアーク倣い溶接装置は、溶接方向に対してトーチを揺動させるウィービング機能、およびアーク倣い機能を備えた消耗電極型のアーク倣い溶接装置であって、前記消耗電極へ溶接電流及び溶接電圧を供給し、前記ウィービングの周波数よりも高い周波数の高周波成分を前記溶接電流及び溶接電圧に含めることが可能に構成されている溶接電源と、溶接中における溶接電流を検出する電流検出器と、溶接中における溶接電圧を検出する電圧検出器と、前記トーチの溶接線からのズレを検出するズレ検出器を有し、前記ズレ検出器は、前記電流検出器により検出された電流と前記電圧検出器により検出された電圧とから溶接中における溶接電流及び溶接電圧から抵抗値を求め、求められた前記抵抗値と前記ウィービングの振幅両端位置に関する情報とから前記トーチの溶接線からのズレを検出する。
以下においては、溶接動作を行う機器を、溶接トーチ1を溶接方向に対して揺動動作(ウィービング動作)させる多関節の溶接ロボットとして説明するが、これは一例に過ぎず、専用の自動溶接装置であっても構わない。
図1は溶接ロボット5による倣いシステム構成図である。
垂直多関節型のロボットシステムは、溶接ロボット5と、教示ペンダント(図示略)を備えた制御装置6を含む。溶接ロボット5は垂直多関節型の6軸の産業用ロボットであり、その先端に溶接トーチ1などから構成される溶接ツールが設けられている。この溶接ロボット5はそれ自体を移動させるスライダに搭載されていてもよい。
アーク溶接は溶接トーチ1から供給される溶接ワイヤ3(消耗電極)と母材4の間に溶接電源2で電圧を印加し、溶接ワイヤ3と母材4の間でアークを発生させる。そのアーク熱で母材4と溶接ワイヤ3を溶融させながら溶接する。アーク溶接に伴い溶接ワイヤ3は溶け落ちてゆくため、溶接中は送給装置により溶接トーチ1内を経由して溶接ワイヤ3が供給され続ける。つまり、このアーク溶接は、消耗電極型の溶接となっている。
溶接電源2は、予めプログラムされた任意の電圧波形を出力することが可能である。例えば、所定の周波数が重畳された波形や所定の周波数のパルス波形を出力することが可能である。溶接電源2には電圧検出器及び電流検出器(ともに図示せず)が内蔵されていて、実際に出力された電圧及び電流(すなわち、溶接電圧および溶接電流)を測定することが可能である。
一方、中厚板の溶接分野では、溶接ワークのガス切断や曲げによる加工精度が悪い場合がある、溶接ワークを治具矯正できず設置精度が悪い場合がある、溶接ワークが溶接中に治具拘束できず熱ひずみで変形する場合がある、などの原因により、溶接すべき位置である溶接線が常に決められた位置にあるとは限らない。溶接線のズレはおおむね数mmからcmオーダーで発生する。
図3Aに示すように、ウィービング動作を行うと、ウィービング位置によって溶接トーチ1と母材4までの距離(以下、「トーチ高さ」と呼ぶ)が変化する。溶接電源2(図2参照)に対して定電圧制御を行った場合、トーチ高さの変化に伴い、ウィービング位置によって溶接電流も変化する。あるいは、溶接電源2に対して定電流制御を行った場合、トーチ高さの変化に伴い、ウィービング位置によって溶接電圧も変化する。ウィービング中心Bと溶接線が一致している場合、溶接電流はウィービング中心Bを中心に図中左右対称に変化し、ウィービングの振幅両端位置(ウィービング端点)A、Cでの溶接電流は一致する。このようにウィービング端点A、Cでの溶接電流が一致している状態は、正常状態である。
本実施形態においては、上記ズレの量を推定演算するプログラムが図1に示す制御装置6に搭載されている。そのズレ量を求める方法について、以下で説明する。
図4は、ウィービング中心を溶接線から故意に2mmずらし、1秒周期、2mm振幅でウィービング動作をさせた場合の溶接電流の波形である。ウィービング中心が常に2mmズレているため、理論的には、左右端での溶接電流差は一定の筈である。しかし、図4に示すように、左右端での電流差に比べ、電流波形全体での電流変動が大きく、少し左右端の位相がずれるだけで、大きく電流値が変化し、SN比(信号とノイズとの比)が非常に悪いことが分かる。
定電圧溶接電源2を用いた図4と同じ電流情報Iに加え、電圧情報Vも用いて、下記式(1)で得られる抵抗値Rを推定した結果を図5に示す。
・継手位置の左右端による溶接電流値の差異を見るだけではSN比が悪く、更なる高精度化が必要である。
・溶接ワイヤ3の脚長に対して特にウィービング振幅が小さい場合、板厚が薄い場合、などでは更なる高精度化が必要となる。
・単純な抵抗値検出によるアーク倣いは、制御ループの影響を受けるなど、有意な抵抗値変化を捉えられない。
その技術の根幹は、消耗電極へ供給する溶接電流及び溶接電圧が高周波成分を含むようにしておき、溶接中における溶接電流及び溶接電圧から、電極の高さ変動に伴う抵抗値変化を検出し、検出された抵抗値の変化量とウィービングの左右位置とから溶接線のズレを検出することである。
高周波数成分を含むように溶接電源2を制御するには、溶接電源2への電圧または電流指令値がその高周波数成分を含むようにすればよい。あるいは、消耗電極へ供給する溶接電流及び溶接電圧として、パルス波形を採用し、高周波成分としてパルス波形に含まれる高周波成分を使用してもよい。
高周波成分の周波数としては、100Hz以上とすることが好ましい。
第1実施例では、溶接電源2に300Hzの高周波波形を電流値に重畳させ、式(1)に基づき抵抗値を推定した。その際の結果を図7に示す。
図7における波形は、式(1)で算出される抵抗値を示したものであり、図7中の丸印は、電極先端が溶接線の左側端部(図3A,図3Bにおける左側(A))に位置している状況であり、図7中の四角印は、電極先端が開先の右側端部(図3A,図3Bにおける右側(C))に位置している状況である。丸印、四角印の意味は、以下登場する図でも同じである。
電極先端が端部に位置しているタイミングは、制御装置がロボットに出力するウィービング指令において、電極先端が端部に位置することを指令したタイミングにロボットの動作遅れを加味して認識する。
更に、溶接時には抵抗値R以外に、オフセット電圧Voや、インダクタンスLが作用することが想定されるため、式(1)に代えて、下記式(2)に基づき抵抗値Rを推定した結果を図8に示す。
なお、R、L、Voを推定するには、例えば、下記(3)式なる関係から、下記(4)式にてR、L、Voを推定できる。
上記逐次最小自乗法にて(忘却係数をほぼ0.1秒程度となるように与えた)推定した結果が図8である。
なお、左右端での抵抗値の差と溶接線からのズレ量との関係は、予め実験的に求めておけばよい。
図9に示す電流波形は、図8の抵抗値を求めるのに用いたものと同じ電流波形に対して、高周波成分をカットするフィルタ処理を施したものである。これは、高周波成分はノイズとしか作用しないためである。更に、フィルタによる端点の位相のズレは補正した上で、端点での電流差を比較している。
また、高周波成分を残したまま、電流値を検出すると、図13のように高周波の影響で、端点の電流が大きく変動する。少し時間位置がずれるだけでも、電流値が変動する。したがって、左右端での電流値を正しく認識することができない。
そのため、従来技術において電流値を用いる場合は、図14のように高周波成分を大幅にカットするようなフィルタ処理を行った電流波形を使用することで、図9のような端点での電流差を検出することができる。
言い換えれば、従来技術では、高周波成分はノイズでしかなく、除去するしかないものであったが、本実施形態の手法では、積極的に高周波成分を活用することで、抵抗値Rの推定を実現することを可能とした。
第1実施例では、一定電流に高周波成分を重畳させたが、第2実施例では溶接電源2からの出力電流波形としてパルス波形を採用し、高周波成分を追加的に重畳させる代わりに、パルス波形の高周波成分を使用することとした。
第1,2実施例では推定された抵抗値Rの左右端での差異のみに着目したが、左右端近傍での平均値をとるなど、抵抗値Rの左右端での値以外の情報を使用することで、更にノイズに強く、高いSN比が実現できる。
以下に留意点を記載する。
まず、式(1)による推定(Rのみ)及び式(2)による推定(R,L,Vo)の双方とも、溶接電源2の制御帯域以上の高周波成分が必要である。パルス波形を用いた場合においても、ロボットコントローラに取り込まれる電流・電圧値がローパスフィルタによってノイズ除去(高周波成分が除去)されていれば、図6の定電圧特性となるように制御されている状況では、Rの推定は難しい。
また、式(2)による推定では、溶接電源2から電流・電圧に加え、電流の微分値も併せてサンプリングするとよい。
2 溶接電源
3 溶接ワイヤ
4 母材
5 溶接ロボット
6 制御装置
Claims (8)
- 溶接方向に対してトーチを揺動させるウィービング機能を備えた消耗電極型の溶接装置におけるアーク倣い溶接方法であって、
前記消耗電極へ供給する溶接電流及び溶接電圧に、前記ウィービングの周波数よりも高い周波数の高周波成分が含まれるようにし、
溶接中における前記溶接電流及び溶接電圧を検出し、
検出された前記溶接電流及び溶接電圧から抵抗値を求め、
求められた前記抵抗値と前記ウィービングの振幅両端位置に関する情報とから、前記トーチの溶接線からのズレを検出する。 - 請求項1に記載のアーク倣い溶接方法であって、
前記高周波成分を前記消耗電極へ供給する溶接電流又は溶接電圧の直流成分より大きくする。 - 請求項1に記載のアーク倣い溶接方法であって、
前記消耗電極へ供給する前記溶接電流及び溶接電圧をパルス波形とし、前記パルス波形に含まれる高周波成分を前記高周波成分として使用する。 - 請求項1に記載のアーク倣い溶接方法であって、
前記高周波成分の周波数が100Hz以上である。 - 溶接方向に対してトーチを揺動させるウィービング機能、およびアーク倣い機能を備えた消耗電極型のアーク倣い溶接装置であって、
前記消耗電極へ溶接電流及び溶接電圧を供給し、前記ウィービングの周波数よりも高い周波数の高周波成分を前記溶接電流及び溶接電圧に含めることが可能に構成されている溶接電源と、
溶接中における溶接電流を検出する電流検出器と、
溶接中における溶接電圧を検出する電圧検出器と、
前記トーチの溶接線からのズレを検出するズレ検出器を有し、
前記ズレ検出器は、前記電流検出器により検出された電流と前記電圧検出器により検出された電圧とから溶接中における溶接電流及び溶接電圧から抵抗値を求め、求められた前記抵抗値と前記ウィービングの振幅両端位置に関する情報とから前記トーチの溶接線からのズレを検出する。 - 請求項5に記載のアーク倣い溶接装置であって、
前記高周波成分を前記消耗電極へ供給する溶接電流又は溶接電圧の直流成分より大きくすることが可能に構成されている。 - 請求項5に記載のアーク倣い溶接装置であって、
前記消耗電極へ供給する前記溶接電流及び溶接電圧をパルス波形として出力することが可能に構成されている。 - 請求項5に記載のアーク倣い溶接装置であって、
前記高周波成分の周波数を100Hz以上とすることが可能に構成されている。
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
KR1020187028271A KR102090049B1 (ko) | 2016-04-04 | 2017-03-10 | 아크 트래킹 용접 방법 및 아크 트래킹 용접 장치 |
US16/090,803 US11065704B2 (en) | 2016-04-04 | 2017-03-10 | Arc-tracking welding method and arc-tracking welding apparatus |
EP17778920.3A EP3441176A4 (en) | 2016-04-04 | 2017-03-10 | ARC WELDING METHOD AND ARC WELDING DEVICE |
CN201780021721.2A CN108883487B (zh) | 2016-04-04 | 2017-03-10 | 电弧仿形焊接方法以及电弧仿形焊接装置 |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2016-075181 | 2016-04-04 | ||
JP2016075181A JP6720452B2 (ja) | 2016-04-04 | 2016-04-04 | アーク倣い溶接方法 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2017175541A1 true WO2017175541A1 (ja) | 2017-10-12 |
Family
ID=60001077
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2017/009826 WO2017175541A1 (ja) | 2016-04-04 | 2017-03-10 | アーク倣い溶接方法およびアーク倣い溶接装置 |
Country Status (6)
Country | Link |
---|---|
US (1) | US11065704B2 (ja) |
EP (1) | EP3441176A4 (ja) |
JP (1) | JP6720452B2 (ja) |
KR (1) | KR102090049B1 (ja) |
CN (1) | CN108883487B (ja) |
WO (1) | WO2017175541A1 (ja) |
Families Citing this family (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP6339651B1 (ja) | 2016-12-02 | 2018-06-06 | ファナック株式会社 | アーク溶接ロボットシステム |
US11065707B2 (en) * | 2017-11-29 | 2021-07-20 | Lincoln Global, Inc. | Systems and methods supporting predictive and preventative maintenance |
US11897060B2 (en) | 2017-11-29 | 2024-02-13 | Lincoln Global, Inc. | Systems and methods for welding torch weaving |
US11027362B2 (en) * | 2017-12-19 | 2021-06-08 | Lincoln Global, Inc. | Systems and methods providing location feedback for additive manufacturing |
JP7251988B2 (ja) * | 2019-01-22 | 2023-04-04 | 株式会社神戸製鋼所 | パルスアーク溶接の倣い制御方法、制御装置、溶接システム、溶接プログラム及び溶接電源 |
CN111843120B (zh) * | 2020-08-07 | 2022-01-07 | 北京时代科技股份有限公司 | 基于电弧传感和位置前馈的机器人焊缝跟踪算法 |
JP7420690B2 (ja) * | 2020-10-12 | 2024-01-23 | 株式会社神戸製鋼所 | アーク倣い溶接方法および溶接装置 |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS59185575A (ja) * | 1983-04-06 | 1984-10-22 | Mitsubishi Electric Corp | 溶接線追従装置 |
JPS60118377A (ja) * | 1983-11-30 | 1985-06-25 | Kobe Steel Ltd | 短絡移行ア−ク溶接における溶接ワイヤ突出長検出方法 |
JPH09262675A (ja) * | 1996-03-28 | 1997-10-07 | Tokyo Gas Co Ltd | パイプ円周自動溶接装置の左右アーク倣い補正方法 |
Family Cites Families (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AT411340B (de) * | 1999-11-08 | 2003-12-29 | Fronius Schweissmasch Prod | Verfahren zum positionieren eines schweissbrenners im mittel eines schweissnahtsollverlaufes |
AT410641B (de) * | 2000-04-05 | 2003-06-25 | Fronius Schweissmasch Prod | Verfahren zum fortlaufenden regeln bzw. nachführen einer position eines schweissbrenners bzw. eines schweisskopfes |
JP5081134B2 (ja) | 2008-11-18 | 2012-11-21 | 株式会社ダイヘン | ロボット用アークセンサの倣いパラメータの設定方法、及びロボット用アークセンサの倣いパラメータの設定装置 |
CN102615389B (zh) * | 2012-03-31 | 2014-08-27 | 上海交通大学 | 基于dsp的弧焊机器人摆动电弧跟踪***和方法 |
US20140001168A1 (en) * | 2012-06-27 | 2014-01-02 | Lincoln Global, Inc. | Parallel state-based controller for a welding power supply |
JP6038505B2 (ja) * | 2012-06-27 | 2016-12-07 | 八千代工業株式会社 | 開閉式天窓 |
CN102773588B (zh) * | 2012-08-04 | 2015-01-07 | 深圳市瑞凌实业股份有限公司 | 弧压跟踪脉冲埋弧焊控制方法、控制电路及焊机 |
CN103447662B (zh) * | 2013-08-20 | 2015-04-15 | 江苏科技大学 | 窄间隙焊缝偏差的脉冲电弧传感检测方法 |
JP6309161B2 (ja) * | 2016-03-25 | 2018-04-11 | バンドー化学株式会社 | 研磨材 |
JP2018185575A (ja) * | 2017-04-24 | 2018-11-22 | ヤフー株式会社 | 提供装置、提供方法、及び提供プログラム |
-
2016
- 2016-04-04 JP JP2016075181A patent/JP6720452B2/ja active Active
-
2017
- 2017-03-10 US US16/090,803 patent/US11065704B2/en active Active
- 2017-03-10 KR KR1020187028271A patent/KR102090049B1/ko active IP Right Grant
- 2017-03-10 WO PCT/JP2017/009826 patent/WO2017175541A1/ja active Application Filing
- 2017-03-10 EP EP17778920.3A patent/EP3441176A4/en not_active Withdrawn
- 2017-03-10 CN CN201780021721.2A patent/CN108883487B/zh active Active
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS59185575A (ja) * | 1983-04-06 | 1984-10-22 | Mitsubishi Electric Corp | 溶接線追従装置 |
JPS60118377A (ja) * | 1983-11-30 | 1985-06-25 | Kobe Steel Ltd | 短絡移行ア−ク溶接における溶接ワイヤ突出長検出方法 |
JPH09262675A (ja) * | 1996-03-28 | 1997-10-07 | Tokyo Gas Co Ltd | パイプ円周自動溶接装置の左右アーク倣い補正方法 |
Also Published As
Publication number | Publication date |
---|---|
CN108883487B (zh) | 2021-02-23 |
CN108883487A (zh) | 2018-11-23 |
EP3441176A1 (en) | 2019-02-13 |
KR20180121944A (ko) | 2018-11-09 |
EP3441176A4 (en) | 2019-12-11 |
US20200198041A1 (en) | 2020-06-25 |
KR102090049B1 (ko) | 2020-03-17 |
JP6720452B2 (ja) | 2020-07-08 |
JP2017185513A (ja) | 2017-10-12 |
US11065704B2 (en) | 2021-07-20 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
WO2017175541A1 (ja) | アーク倣い溶接方法およびアーク倣い溶接装置 | |
KR101801456B1 (ko) | 숨겨진 결합 이음매를 갖는 워크피스의 결합 | |
CN109963679B (zh) | 电弧跟踪焊接中的偏移量的检测方法 | |
JP6052798B2 (ja) | 自動溶接機の異常監視装置 | |
WO2018088372A1 (ja) | アーク溶接の表示装置及び表示方法 | |
JP2014030841A (ja) | アーク倣い溶接方法および溶接装置 | |
WO2018092514A1 (ja) | アーク倣い溶接でのズレ量検出方法 | |
KR101603919B1 (ko) | 위빙 용접 장치 및 용접선과 토치간 높이 제어 방법 | |
CN114951906A (zh) | 焊接***和用于运行焊接***的方法 | |
JP2009183976A (ja) | 溶接制御方法および溶接装置 | |
CN114682878A (zh) | 用于运行焊接机器人的具有焊缝跟踪的焊接方法 | |
KR101615903B1 (ko) | 자동 용접 제어장치 | |
JP2002239733A (ja) | 溶接線の倣い判定装置と倣い制御装置 | |
US5066847A (en) | Automatic welding machine path correction method | |
JP2002239732A (ja) | 溶接線倣い制御方法 | |
JP3209139B2 (ja) | 溶接条件適応制御方法 | |
JP3077931B2 (ja) | 溶接方法 | |
JPH0426942B2 (ja) | ||
JPH10272572A (ja) | アーク溶接による溶接方法 | |
Pires et al. | Sensors for Welding Robots | |
JPS61226181A (ja) | 自動溶接傚い装置における傚い制御方法 | |
JPS6174780A (ja) | 自動ア−ク溶接方法 |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
ENP | Entry into the national phase |
Ref document number: 20187028271 Country of ref document: KR Kind code of ref document: A |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2017778920 Country of ref document: EP |
|
ENP | Entry into the national phase |
Ref document number: 2017778920 Country of ref document: EP Effective date: 20181105 |
|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 17778920 Country of ref document: EP Kind code of ref document: A1 |