Apparatus for welding control systems and methods for generating force when controlling welding tools.

Abstract

A device (50, 50A) for a welding control system (10) and a method for verifying the reliability of force values ​​when controlling a welding tool (21) are provided. The device (50, 50A) has a function for measuring at least one welding tool parameter (A... B The measurement module (51) for M_B) and the welding tool parameters (A) measured by the measurement module (51) B The actual force (F) generated in M_B during the welding process using the welding tool (21) is generated. S (t), F S_ACT The force value generation module (52) of the welding tool (A) wherein at least one welding tool parameter (A) B The force (M_B) depends on the drive of the welding tool (21) relative to at least one component (5, 6) during the welding process, wherein the force value generation module (52) is configured to generate the actual force (F) using a model (511) of the welding tool (21). S (t), F S_ACT ).

Description

Technical Field

[0001] The present invention relates to an apparatus for a welding control system and a method for generating force values ​​when controlling welding tools. Background Technology

[0002] Metal parts can be joined using welding tools. For example, welding tools are used in industrial equipment, particularly vehicle production lines. Here, metal parts, especially sheet metal, are joined by welding using these tools. In automated vehicle body frame manufacturing, welding clamps with electrode caps on welding electrodes are used as welding tools. During resistance welding, the two welding electrodes of the welding clamp press against the components to be welded at the welding location. This forms a circuit in which a welding core is formed between the components with a specific current variation curve. In spot welding / resistance welding, the consistent quality of the weld point is crucial.

[0003] Such welding clamps are, for example, configured as electrically servo-driven welding clamps to apply force to compress the clamps and form a weld point. If the force applied to the welding clamps is too great, the clamps will be damaged. Therefore, the use of a force adjuster is advantageous in order to measure the force applied to the welding clamps so as not to cause damage to the clamps or welding tools.

[0004] The force regulator uses the measured force value, or so-called actual force, during force adjustment. The actual force is measured using a force sensor.

[0005] However, the problem is that the force sensor is expensive to install. Furthermore, the force sensor requires repeated maintenance, especially calibration, to avoid outputting incorrect actual force values ​​or erroneous actual force values.

[0006] If an incorrect actual force value is output, the wrong measured force will be used when adjusting and monitoring the operation of the welding tool. In this case, using an incorrect actual force value when adjusting the force of the welding tool, especially a motorized servo welding clamp, will lead to incorrect force settings. This can result in poor weld quality, such as open welds, excessive spatter, and damage to the welding tool. Summary of the Invention

[0007] Therefore, the object of the present invention is to provide an apparatus for a welding control system and a method for generating force values ​​when controlling welding tools, wherein the apparatus and method can solve the above-mentioned problems. In particular, an apparatus for a welding control system and a method for generating force values ​​when controlling welding tools should be provided, wherein the force generated for any type of welding tool controlled by the welding control system in industrial equipment can be set such that the consistent quality of the welded joint can be achieved with less installation and maintenance costs and higher operational safety and accuracy.

[0008] This task is solved by an apparatus for a welding control system according to the invention. The apparatus has a measuring module and a force generating module, wherein the measuring module is used to measure at least one welding tool parameter, which depends on the driving of the welding tool relative to at least one component during welding, and wherein the force generating module is used to generate an actual force occurring during welding from the welding tool parameter measured by the measuring module, wherein the force generating module is configured to generate the actual force using a model of the welding tool.

[0009] The aforementioned device can regulate the establishment of welded joints with the required high quality without the need for force sensors. This saves resources. Furthermore, it reduces the cost of force sensors for welding equipment.

[0010] Furthermore, since force sensors are not required, the time spent on their commissioning, calibration, and maintenance, especially the calibration itself, is eliminated. This translates to significant additional cost savings for the welding control system.

[0011] Nevertheless, the device prevents damage to welding tools. This avoids the high-cost maintenance required to repair welding equipment malfunctions. Therefore, the welding control system significantly extends the service life of welding tools.

[0012] Overall, the device ensures that the desired quality of the established weld joints can be achieved. For example, in the case of force adjustment, it can avoid weld spatter and the resulting poor weld quality in cases where the actual force value is incorrectly measured, particularly if it is measured too much. This reduces the amount of waste produced by industrial equipment.

[0013] In summary, this minimizes the failure rate of welding equipment in industrial facilities. Ultimately, this increases the output of industrial equipment.

[0014] Other advantageous designs of the device are described in other parts of this disclosure.

[0015] The model can model welding tools as springs and can have at least one spring parameter that defines the spring.

[0016] It is conceivable that the at least one spring parameter is an equivalent spring constant having at least one spring constant related to the mechanical properties of the welding tool and a spring constant related to the properties of at least one component to be welded.

[0017] As a supplementary or alternative solution, it is possible to consider that the at least one spring parameter is a dead time, which delays the formation of the force used to establish the weld joint after a force is applied to the welding tool.

[0018] In one particular design, the force generation module can be configured to take into account changes in the parameters of a given spring during the welding process.

[0019] According to one embodiment, the at least one welding tool parameter is the arm bend of the welding tool, which is a function of the actual position of at least one electrode of the welding tool. As a supplementary or alternative embodiment, according to another embodiment, the at least one welding tool parameter is the acceleration torque of at least one electrode of the welding tool, and the acceleration torque is a function of the actual rotational speed of the drive mechanism used to drive the at least one electrode of the welding tool.

[0020] According to another alternative, the force generation module is configured to take into account the force changes that occur during welding with a welding tool in order to generate an actual force, wherein the force changes occur due to the thermal expansion of the at least one component and / or due to the at least one electrode sinking into the at least one component at the molten position and / or due to welding spatter.

[0021] The aforementioned device can be part of a welding control system for welding tools, which in turn has a force adjustment module for adjusting the force variation curve. When a weld joint is established, at least one electrode of the welding tool applies the force to at least one component. The force adjustment module is connected to the device such that it uses the actual force generated by the device to adjust the force variation curve.

[0022] Here, the device can also be configured to measure the difference between actual force values ​​generated by a measuring module for different welding tool parameters at the same time during welding with welding tools, wherein the device is configured to notify the welding control system to interrupt the welding process if the measured difference is too large.

[0023] Furthermore, the aforementioned welding control system can have a setting module for evaluating the adjustment of the force adjustment module, wherein the setting module is configured to model the welding tool as a spring and set at least one regulator parameter of the force adjustment module based on at least one parameter of the determined spring.

[0024] The aforementioned device can be part of a welding apparatus, which further includes a welding tool and a welding control system, wherein the welding tool has at least one electrode for establishing a welded joint on at least one component, and wherein the welding control system is used to control the establishment of the welded joint using the welding tool, wherein the force adjustment module is connected to the device such that the force adjustment module uses the actual force generated by the device to adjust the force variation curve.

[0025] Here, the welding tool can be a resistance welding tool, which is constructed as a welding clamp with two electrodes.

[0026] Furthermore, the task is solved by a method according to the invention for generating force values ​​when controlling a welding tool. The method is implemented using an apparatus for a welding control system and includes the following steps: measuring at least one welding tool parameter using a measuring module, the welding tool parameter depending on the drive of the welding tool relative to at least one component during welding with the welding tool; and generating an actual force from the welding tool parameter measured by the measuring module using a force value generation module, the actual force occurring during welding with the welding tool, wherein the force value generation module generates the actual force using a model of the welding tool.

[0027] The method achieves the same advantages as those mentioned earlier regarding the device.

[0028] Other possible implementations of the invention include combinations of features or implementations not explicitly mentioned in the preceding or following descriptions of the embodiments. Those skilled in the art can also add individual aspects as improvements or supplements to the corresponding basic form of the invention. Attached Figure Description

[0029] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. Wherein it is shown that:

[0030] Figure 1 A greatly simplified schematic diagram of an industrial apparatus having a welding device according to a first embodiment is shown, the welding device using a welding control system for controlling welding tools and a means for generating actual force values ​​on the welding tools;

[0031] Figure 2A cross-sectional view of the welding electrode of the welding tool according to the first embodiment in operation is shown when the welding tool is not yet ready to perform welding.

[0032] Figure 3 A cross-sectional view of the welding electrode of the welding tool according to the first embodiment in operation is shown when the welding tool is ready to perform welding and a welded joint has been established.

[0033] Figure 4 A diagram illustrating the equivalent model of a C-clamp as three springs connected in series is shown.

[0034] Figure 5 It is shown that in a clamping closing motion V ACT A graph showing the time-varying force of a specific instance of a step input velocity;

[0035] Figure 6 A simplified view of an adjustment circuit for adjusting force according to a first embodiment is shown, wherein the force is applied to the welding position by a welding tool during a welding or maintenance process.

[0036] Figure 7 A flowchart of a method is shown, which is implemented by means of a device according to a first embodiment for generating an actual force value on a welding tool and used in establishing a welded joint; and

[0037] Figure 8 A diagram of a device for generating an actual force value on a welding tool, according to a second embodiment, is shown. Detailed Implementation

[0038] In the accompanying drawings, unless otherwise specified, the same or functionally equivalent elements are given the same reference numerals.

[0039] Figure 1 An industrial apparatus 1 is shown, comprising a welding device 2 for welding at least one metal component 5, 6. Here, the at least one metal component 5, 6 is connected by at least one welded joint 7. The at least one welded joint 7 is, for example, a weld point and / or a weld seam. Here, only two edges of two metal components 5, 6, or one of said components 5, 6, can be connected to each other. Weld spatter 8 may undesirably occur during welding.

[0040] The industrial equipment 1 is, for example, a production line for vehicles, furniture, buildings, etc., in which metal components 5 and 6 are welded. For this purpose, the welding equipment 2 has a welding control system 10, a first device 20 for guiding a welding tool 21, implemented as a resistance welding tool, having two welding electrodes 22 and 23, a detection mechanism 30 for providing data 35, an operating mechanism 40, and a second device 50. The first device 20 is controlled by the control mechanism 25. Furthermore, communication lines 41 to 45 are provided, which can be implemented as a bus system. The operating mechanism 40 can output notifications 48, especially status notifications and / or fault notifications and / or other information. The second device 50 is used to generate the actual force value of the welding tool 21 during the welding process. For this purpose, the device 50 uses at least a portion of the data 35.

[0041] The device 20 is, in particular, a robot. The manipulation mechanism 40 can be implemented, for example, as a keyboard and / or mouse, a laptop computer, a touch-sensitive or touch-insensitive screen, or a combination thereof.

[0042] according to Figure 1 The welding tool 21 is a welding clamp with at least one electrode 22, 23. In particular, the welding tool 21 is an electrically servo-driven welding clamp. Figure 1 In one example, the welding clamp is constructed as a C-type clamp. It is feasible that one of the clamp arms—with an electrode 22 disposed at its end, for example—is a movable clamp arm, while the other clamp arm—with an electrode 23 disposed at its end, for example—is a fixed clamp arm. A detection mechanism 30, particularly a force sensor, can be mounted on the fixed clamp arm. Of course, other variations for implementing the welding tool 21 and / or for arranging the detection mechanism 30 on the welding tool 21 are also feasible.

[0043] The welding control system 10 is used to control the welding tool 21. Therefore, the welding control system 10 is connected to the welding tool 21 or its electrical components via a communication line 41. Furthermore, the welding control system 10 is connected to the operating mechanism 40 via a communication line 42. As a supplement, the welding control system 10 receives data 35 detected by the detection mechanism 30 during the operation of the welding tool 21 via the communication line 41. For this purpose, the detection mechanism 30 has at least one sensor for detecting physical parameters that are important during welding and are referred to below as data 35. Such physical parameters or data 35 include, in particular, the temperature during the welding process for establishing the weld joint 7, the position of the electrodes 22, 23 in space and / or relative to at least one component 5, 6, or other physical parameters during welding.

[0044] Therefore, the detection mechanism 30 particularly includes at least one position sensor, such as a rotary encoder and / or a gyroscope sensor and / or a motion sensor. As a supplementary or alternative, the detection mechanism 30 can particularly include a temperature sensor. As a supplementary option, the detection mechanism 30 can include at least one sensor for detecting at least one electrical parameter during the welding process, particularly for detecting the welding current Is.

[0045] The welding control system 10 has a setting module 11, a force adjustment module 12, and a memory module 13. Optionally, the setting module 11 is used to set the regulator parameters of the force adjustment module 12, which can optionally be done by evaluating data 35, which is stored in the memory module 13.

[0046] To control the welding process performed with welding tool 21, internal basic parameters or ratings 131 are stored in the welding control system 10, more precisely in its memory module 13. These internal basic parameters or ratings can be input by the user either at the factory or later via the operating mechanism 40. The internal basic parameters or ratings 131 can be parameters of the welding tool 21. Furthermore, the internal basic parameters or ratings 131 can be parameters of the welding control system 10 used to control the welding tool 21. In particular, the internal basic parameters or ratings 131 are the phase angle of the welding current Is and / or the resistance R and / or holding force and / or clamping force Fs of the welding tool 21 and / or at least one limit value—the limit value used to determine whether a notification 48 should be output on the operating mechanism 40—especially a status notification and / or fault notification and / or other information. The welding current Is is transmitted through... Figure 1 A welding transformer (not shown) is fed to welding tool 21. This should be referenced. Figure 2 Provide a detailed description.

[0047] All internal basic parameters or ratings 131 can be stored as time-dependent parameters or rating-time variation curves of the corresponding rated parameters. Therefore, in particular, it is possible to store the welding current Is(t) and / or resistance R(t) and / or holding force and / or clamping force Fs(t) of the welding tool 21. Here, it is possible to store continuous time variation curves or intermittently determined time variation curves.

[0048] The detection mechanism 30 outputs at least a portion of its data 35 to the second device 50. The data 35 specifically includes the temporally variable actual positions L of the electrodes 22 and 23. ACT Or the actual position L of electrode 22 on the movable clamp arm that is at least temporally variable. ACTSubsequently, the device 50 is able to transmit the data 35 to the welding control system 10.

[0049] The second device 50 has a measuring module 51 and a force value generating module 52. The measuring module 51 is used to measure, and in particular calculate, the arm bending A of the welding tool 21. B Here, the device 50 uses a model 511 of the welding tool 21 to determine the modeled position of the welding tool 21. The force value generation module 52 is used to generate the actual force value F of the holding force and / or clamping force Fs during the welding process. S_ACT Or Fs(t). For this purpose, the force generation module 52 uses the previously measured arm bending A of the welding tool 21. B The force value generation module 52 will generate the actual force value F. S_ACT The actual force value F is transmitted to the welding control system 10. S_ACT It can be used to adjust the welding process performed with welding tool 21. This will be described in more detail below.

[0050] When the welding tool 21 is guided by the arm 24 of the device 20, the device 20 is controlled by its control mechanism 25. For this purpose, the control mechanism 25 is connected to the welding control system 10 via a communication line 43. Alternatively, the control mechanism 25 is connected to the operating mechanism 40 via a communication line 44. The opening or closing of the welding tool 21 is achieved by driving the drive mechanism 26.

[0051] As a supplementary or alternative solution, the control mechanism 25 is directly connected to the electrical components of the detection mechanism 30 and / or welding tool 21 via communication line 45. If there is no redundancy requirement, the communication line 43 can be omitted.

[0052] Through communication lines 42 to 45, relevant data concerning welding performed with the welding tool 21 can be exchanged between the welding control system 10 and the device 20, more precisely, the control mechanism 25 and / or the operating mechanism 40. Furthermore, the control mechanism 25 can store internal basic parameters or ratings 251, which are used to control the welding tool 21, particularly for positioning it in space and thus on components 5 and 6.

[0053] Figure 2The construction of electrodes 22 and 23 of the welding tool 21 in this embodiment is shown in more detail. Electrode 22 is constructed as an electrode rod with an electrode cap 220 at one end. The electrode cap 220 is disposed on the end of electrode 22 facing member 5. The electrode cap 220 has an axis 221, which is the same as the axis of electrode 22. Furthermore, electrode 23 is constructed as an electrode rod with an electrode cap 230. The electrode cap 230 is disposed on the end of electrode 23 facing member 6. The electrode cap 230 has an axis 231, which is the same as the axis of electrode 23.

[0054] exist Figure 2 In this example, electrode 22 is mounted on a movable jaw arm of welding tool 21. Electrode 23 is mounted on a fixed jaw arm of welding tool 21. In this example, the jaw arm of welding tool 21 is open. Thus, axes 221 and 231 are transverse to each other. At least one component 5 or 6 has a thickness D between electrodes 22 and 23, more specifically between their electrode caps 220 and 230.

[0055] Figure 2 The operating state exists when the welding tool 21 is positioned on the components 5 and 6 at the location to be welded. In this operating state, the welding tool 21 is not yet ready for welding. Therefore, the welding current Is has not yet been supplied by the welding transformer 27.

[0056] The welding tool 21 can be processed using a cleaning mechanism 60, shown schematically, such that contaminated portions of one of the electrode caps 220, 230 can be cut or milled when necessary. This cleaning mechanism can be implemented as a milling and / or cutting mechanism or a replacement mechanism. Therefore, the electrode caps 220, 230 are wear objects.

[0057] like Figure 3 As shown, the electrodes 22 and 23 are arranged on at least one component 5 and 6 on both sides of the position to be welded during the operation of the welding tool 21, and are placed on at least one component 5 and 6 by means of holding force and / or clamping force Fs. Thus, the axes 221 and 231 are ideally arranged in a line.

[0058] In other words, in Figure 3 In operation, the two electrodes 22 and 23 clamp the components 5 and 6 with a force Fs. The electrodes 22 and 23 are fed toward the at least one component 5 and 6 to varying degrees depending on the number of milling and / or cutting processes performed on the electrode caps 220 and 230, in order to obtain the desired force Fs.

[0059] In this state where the welding tool 21 is closed and a force Fs has been generated, arm bending A occurs. B The clamp arm of the welding tool 21 behaves like a spring, as will be described in detail below.

[0060] The welding current Is is then delivered to the electrodes 22 and 23 for a predetermined duration T and with predetermined characteristics by means of the welding transformer 27. For this purpose, a current Is with a defined current variation curve is delivered, especially when at least partially regulated. This generates heat in at least one component 5 or 6, thereby forming a welding core, which later forms the welded joint 7.

[0061] As mentioned earlier, during the operation of the welding tool 21, data 35 is detected by the detection mechanism 30. Since no force sensor is available, the device 50 takes the following actions.

[0062] The device 50 uses a model 511 of the welding tool 21 to determine the modeled position of the welding tool 21, particularly the bending angle of the arm of the welding tool 21. B Here, model 511 assumes the welding tool 21 to be a spring. Therefore, as referenced... Figure 4 As explained in more detail, in model 511, an equivalent spring constant k_E is assigned to the welding tool 21. This equivalent spring constant k_E is measured when the welding tool 21 is in operation, particularly when using a force gauge (Kraftmessdose).

[0063] In model 511, the actual position L during the welding process is... ACT , Predetermined position L G and thickness D as

[0064] A B =L_ACT-L G +D (1)

[0065] To calculate the arm bending A of the welding tool 21 during the welding process and / or during the progress of the welding process. B .

[0066] The predetermined position L of equation (1) G This is referred to as the actual position when welding tool 21 is closed. In this position, L... G In this configuration, the welding tool 21 is closed and no components 5 or 6 with thickness D are arranged between electrodes 22 and 23. Therefore, the electrodes 22 and 23 of the welding tool 21, and consequently their electrode caps 220 and 230, are arranged at a predetermined position L. G superior.

[0067] If the measurement module 51 has already measured the corresponding actual arm bend A B Then the force generation module 52 can use the following equation (2) with the equivalent spring constant k_E:

[0068] F s_ACT =k_E*A B (2)

[0069] To calculate and thus generate the actual force F S_ACT .

[0070] As can be read from equation (2), the arm of the welding tool 21 bends by A. B The actual force F depends on the holding force and / or clamping force Fs. S_ACT That is, the actual force F of the holding force and / or clamping force Fs. S_ACT The larger the arm bends, the greater the bending A. B The larger the force, the greater the actual force F when the clamp arm of the welding tool 21 is opened. S_ACT =0. Therefore, in this state, the arm bending is also A. B =0.

[0071] according to Figure 4 The equivalent spring constant k_E is derived from the equivalent model 210 of the welding tool 21, which is based on model 511 and used by the device 50. The equivalent model 210 models the welding tool 21 as a spring, more precisely, as a series connection of springs 211, 212, and 213. Here, spring 213 is arranged between springs 211 and 212. The total springs, and thus the welding clamp 21 modeled accordingly, are determined by the equivalent spring constant k_E and the dead time Tt. The dead time Tt is... Figure 5 As shown in the diagram, Figure 5 V in the clamp movement ACT The actual force F of the holding force and / or clamping force Fs is shown as the actual input step speed with respect to time t. S_ACT .exist Figure 5 In the example, the actual force F S_ACT It is expressed in physical units N and time t is expressed in physical units ms.

[0072] Spring 211 represents the mechanical characteristic of the first clamping arm of welding tool 21, which is movable. Spring 212 represents the mechanical characteristic of the second clamping arm of welding tool 21, which is fixed. Spring 213 represents the mechanical characteristic of at least one component 5, 6.

[0073] Spring 211 has a spring constant k_F1. Spring 212 has a spring constant k_F2. Spring 213 has a spring constant k_F3. Through series connection, according to the following equation (3):

[0074] 1 / k_E=1 / k_F1+1 / k_F2+1 / k_F3 (3)

[0075] The total spring constant or equivalent spring constant k_E is obtained.

[0076] Therefore, the total spring constant or equivalent spring constant k_E is always less than the individual spring constants k_F1, k_F2, and k_F3. Thus, the combination of springs 211 to 213 produces a softer total spring. The force F varies with time t. S (t) In the series connection of springs 211 to 213, each spring 211 to 213 acts in the same amount.

[0077] The device 50, and in particular its measuring module 51, can be represented by the following equation (4):

[0078] k_E=ΔF s_ACT / Δs ACT =ΔF s_ACT / v ACT *Δt (4)

[0079] The equivalent spring constant k_E is then calculated. This calculation can be performed, for example, by putting the welding equipment 2 and / or welding tool 21 into operation, as previously described.

[0080] Here, ΔF S_ACT When at a predetermined constant speed V ACT The difference in force detected when at least one clamp arm of the welding tool 21 is driven for a predetermined duration Δt. Here, the clamp arm, i.e., springs 211, 212, and therefore spring 213, is also compressed by a stroke Δs. ACT .

[0081] If the equivalent spring constant k_E and / or the dead time Tt are measured, especially when using a force gauge, the measured equivalent spring constant k_E and / or the measured dead time Tt are stored in data 35 in model 511 and, if necessary, additionally in memory module 13. Therefore, in subsequent welding processes using welding tool 21, the device 50 can utilize the equivalent spring constant k_E and / or the dead time Tt.

[0082] As an alternative, it is feasible not to use it as an actual force F. S_ACT Instead, it is used as a polynomial of order 1 to 3 in the following equation (5):

[0083] A B =a*F s_ACT 3 +b*F s_ACT 2 +C**F s_ACT +d (5)

[0084] To measure the arm bending A B .

[0085] The identification of coefficients a, b, c, and d is performed using an approximation method, which involves bending the arm A across the entire range of use of the welding tool 21 after the previous measurement. B The relative deviation between the calculated and measured values ​​is minimized. The least squares method is used here. The determination of the equivalent spring constant k_E is a special case of this method, where the coefficients a, b, and d are set to zero. If c is the equivalent spring constant k_E, then it is represented by equation (6):

[0086] AB = c * F S_ACT =k_E*F S_ACT (6)

[0087] The conclusion is as follows.

[0088] During or in the course of welding, the actual force F S_ACT The actual force F increases due to the thermal expansion of the material of at least one component 5 or 6 after the welding current Is is introduced. S_ACT The force F decreases after at least one of the components 5 and 6 melts for welding connection 7. If welding spatter 8 occurs, then the actual force F... S_ACT Similarly, it decreases. Therefore, during or in the course of the welding process, the actual force F... S_ACT And the arm bending A of the welding tool 21 described theretherein B It changes over time.

[0089] The force generation module 52 can generate the actual force F generated during or in the course of the welding process. S_ACT The force F is transmitted separately or continuously to the welding control system 10, resulting in an actual force F. S_ACT The value can be used when adjusting the force Fs using the force adjustment module 12.

[0090] Figure 6 The structure of the adjustment circuit formed by the force adjustment module 12 for maintaining the force and / or clamping force Fs during the welding process using the welding tool 21 is shown.

[0091] The regulating object (Regelstrecke) 122 is an integral path (I-path). Furthermore, a dead time Tt exists, which acts on the welding tool 21 between the introduction and application of force Fs. Therefore, in the regulating object 122, a time delay occurs in the form of a dead time Tt when force Fs(t) is formed, as previously referred to. Figure 5 As described.

[0092] A welded joint is established during the welding process. Therefore, Figure 6 The force adjustment module 12 and its interconnections with the setting module 11, memory module 13, detection mechanism 30, and device 50 are shown more precisely. Furthermore, the memory module 13 can store data 35, particularly the actual position L generated by the device 50 during the welding process. ACT Furthermore, the memory module 13 stores basic parameters and rated parameters 131, particularly the time-dependent rated force Fs(t) for holding force and / or clamping force. Additionally, the setting parameters 132 of the setting module 11 can be stored in the memory module 13.

[0093] The force adjustment module 12 has an adjuster 121 and an adjustable object 122, wherein the adjuster 121 has specially set adjuster parameters 120. As explained in more detail below, the adjuster 121 in this example is a PD adjuster. The PD controller is a combination of a proportional controller and a derivative controller. The adjustable object 112 is a part of the adjustment loop formed by the force adjustment module 12, which contains the physical parameters to be adjusted, namely, the holding force and / or clamping force Fs. Alternatively, other physical parameters, especially the actual position L, can be adjusted additionally. ACT .

[0094] The force F currently in effect S_ACT The force F is generated by the device 50, as previously explained. S_ACT It is then fed to the PD regulator 121, such as Figure 6 As shown.

[0095] Therefore, the PD regulator 121 acts on the rated parameters, namely the rated force F of the holding force and / or clamping force Fs. S (t) The actual force F generated by device 50 with the holding force and / or clamping force Fs. S_ACT The difference. Therefore, a force F is generated. S_ACT The force acts on electrodes 22 and 23 during the welding process and thus on at least one component 5 and 6.

[0096] The setting module 11 can optionally set the regulator parameter 120. Here, the regulator parameter 120 can be optimized for the desired weld quality produced using the currently used welding tool 21. Alternatively, the setting module 11 can further adjust the set regulator parameter 120 during continuous operation of the welding equipment. For example, this can be achieved by adjusting the adjustment deviation F. S1 =F S (t)-F S_ACT Analysis.

[0097] In a type of force F generated for the welding process S_ACT In the method of numerical determination, the device 50 takes the following actions. Figure 7 As shown in the image.

[0098] Figure 7 Used to generate actual force F S_ACT The value is used to control the welding tool 21, for example, in order to establish a welded joint 7, and is executed during the welding process. During the welding process, under normal circumstances, the welding current I is specified. S To load. However, as an alternative, Figure 7 The method can be performed during maintenance, i.e., without applying welding current I. S .

[0099] In step S1, the measurement module 51 measures the equivalent spring constant k_E according to the previously mentioned equation (4). The measurement module 51 inputs the equivalent spring constant k_E into the model 511 and optionally stores the equivalent spring constant k_E in the memory module 13. After this, the process proceeds to step S2.

[0100] In step S2, the welding process for establishing welded joint 7 can begin. Afterward, the process proceeds to step S3.

[0101] In step S3, the detection mechanism 30 detects the actual position L. ACT This data is then sent as data 35 to device 50. The process then proceeds to step S4.

[0102] In step S4, the measuring module 51 measures the arm bending A according to the previously mentioned equation (1). B And the measured arm bend A B The force value is transmitted to the force value generation module 52. After this, the process proceeds to step S5.

[0103] In step S5, the force value generation module 52 obtains the arm bending A measured in step S4. B Determine the actual force F in the middle S_ACTThe value to which it belongs. That is to say, the force value generation module 52 generates the actual force F using the previously mentioned equation (2). S_ACT The value. After this, the process proceeds to step S6.

[0104] In step S6, the actual force F is used. S_ACT The welding process is carried out using the values ​​generated in step S5. Therefore, as described above, under the control of the welding control system 10, a welded connection 7 is established on at least one component 5, 6 using the welding tool 21. The process then proceeds to step S7.

[0105] In step S7, it is checked whether the welding process should continue. If the welding process should continue, the process returns to step S3. Otherwise, if the welding process should be terminated, the process proceeds to step S8.

[0106] In step S8, it is checked whether the welded connection 7 established in step S3 meets the pre-defined quality requirements. The process then proceeds to step S9.

[0107] In step S9, the result of the check in step S8 is stored in memory module 13. Alternatively or as a supplement, the result of the check in step S8 is output as a corresponding notification 48 at operating mechanism 40. This output can be particularly performed optically and / or acoustically. The method then concludes.

[0108] Figure 7 The previously described step S1 of the method can be performed either before each welding process or before each maintenance process, such as a cleaning process performed using the cleaning mechanism 60. Steps S3 to S5 for predetermined time units are preferably performed at least partially simultaneously with step S6 of the previous time unit, thereby implementing a continuous welding process. Very generally, the generation of the force value Fs can be performed each time the welding tool 21 closes, wherein the actual force F is measured. S_ACT That is to say, measurements are taken, for example, before the welding process (using welding current) or before the maintenance process (without welding current), such as before milling, setting the stroke, etc.

[0109] In the preceding description, model 511 assumed that the spring constant k_F1 of the fixed clamp arm was constant for the corresponding welding tool 21. However, unlike the preceding description, the spring constant k_F1 of the fixed clamp arm may vary for different welding tools 21 during the service life of the welding tool 21 due to mechanical wear. Furthermore, the spring constant k_F1 may change during welding due to the heat generated by the welding tool 21. Therefore, the spring constant k_F1 can change over time as needed. This change can occur during the service life of the welding tool 21 and / or during the welding process, especially during the progress of the welding process.

[0110] Furthermore, model 511 assumes that the spring constant k_F2 of the movable clamping arm is constant for the corresponding welding tool 21. However, for different welding tools 21, the spring constant k_F2 of the movable clamping arm may change due to mechanical wear during the service life of the welding tool 21. Additionally, the spring constant k_F2 may change during welding due to heat generated by the welding tool 21. Therefore, the spring constant k_F2 can change over time as needed. This change can occur during the service life of the welding tool 21 and / or during the welding process, especially during the progress of the welding process.

[0111] Furthermore, unlike the preceding description, model 511 also considers that the spring constant k_F3 of the at least one component 5, 6 changes with time t during the time interval between cleaning processes performed by the cleaning mechanism 60. During the welding process, the spring constant k_F3 changes. For example, due to thermal expansion and due to the melting of components 5, 6. This is reflected in the determination of the actual position L of electrodes 22, 23 during the welding process. ACT The location is the interference quantity.

[0112] The device 50 or model 511 changes the spring constant k_F3 and thus the equivalent spring constant k_E according to the progress of the welding process. Therefore, the device 50 also re-determines the arm bending A of the welding tool 21 according to equation (1). B Furthermore, the device 50 re-measures the actual force F according to equation (2). S_ACT The value of .

[0113] To adjust the equivalent spring constant k_E according to the progress of the welding process, the device 50 uses at least one detection result from the detection mechanism 30. The at least one detection result from the detection mechanism 30 can optionally be retrieved from data 35 in the memory module 13. For example, as a detection result, the device 50 uses the temperature of at least one component 5, 6 detected at the weld point for welding the connection 7. As a supplementary or alternative, as a detection result, the device 50 can use the detected welding current Is flowing during the currently performed welding process.

[0114] Furthermore, the setting module 11 can change the regulator parameter 120 according to the changed equivalent spring constant k_E.

[0115] According to a modified embodiment of this invention, as described above, the setting module 11 does not adjust the deviation F. S1 An evaluation is conducted. In other words, the welding control system 10, particularly its setting module 11, is tested for the actual force F. S_ACT The spectrum is evaluated. Here, the welding control system 10, especially its setting module 11, uses FFT analysis (FFT = Fast Fourier Transform). If the actual force F S_ACT If a maximum value can be identified in the spectrum, then this indicates oscillation. Therefore, the setting module 11 evaluates the maximum value as the presence of force oscillation. In this way, force oscillation can also be identified and avoided.

[0116] Figure 8 A portion of the apparatus 50A and welding tool 21, which can be used in a second embodiment, is shown. The welding tool 21 has a drive mechanism 26 for driving the welding tool 21 to change the arm bending A. B Here, a drive current In is supplied to the drive mechanism 26, causing the drive mechanism 26 to be driven at a predetermined speed n and a predetermined torque Mn. This generates the actual torque Mn. _ACT and actual rotational speed n _ACT .

[0117] Unlike the device 50 according to the foregoing embodiment, the device 50A is configured to perform actions to generate an actual force F. S_ACT The value of .

[0118] During the welding process, the measuring module 51 is driven by the actual rotational speed n of the drive mechanism 26. _ACT The derivative with respect to time t and the weight of welding tool 21 in kg*m 2 The total moment of inertia J_ges in units of

[0119] M_B=2π*J_ges*(d(n_ACT) / dt) (7)

[0120] To measure the accelerating torque M_B acting on electrodes 22 and 23.

[0121] The accelerating torque M_B is the torque that acts during the welding process due to the movement of electrodes 22 and 23 relative to at least one component 5 and 6 driven by the drive mechanism 26. The total moment of inertia J_ges of the welding tool 21 can be measured when the welding tool 21 is put into operation and is stored in the model 511 of the welding tool 21.

[0122] The force generation module 52 then uses the acceleration torque M_B and the actual torque Mn measured according to equation (7) _ACT The feed constant kv, in meters per revolution (m / U), is used as the formula according to equation (8).

[0123]

[0124] To calculate the actual force F S_ACT The feed constant kv is determined by the actual feed rate V of at least one electrode 22, 23 of the welding clamp 21. ACT and the actual rotational speed n of the drive mechanism 26 _ACT Let's calculate it.

[0125] Here, the torque Mn, either the current torque or the actual torque during the welding process, is used. _ACT The difference between the acceleration torque M_B measured by the measurement module 51 and the feed constant kv of the welding tool 21 can be measured when the welding tool 21 is put into operation and stored in the model 511 of the welding tool 21.

[0126] Therefore, a separate position sensor is not required in this embodiment. This further reduces the actual force F used to establish the welded joint 7. S_ACT The cost of supplying the welding control system 10.

[0127] However, if particularly high accuracy and / or redundancy, and consequently security, are required, the actual position L can also be optionally set. ACT The contents are conveyed to the device 50A, such as in Figure 8 As indicated by the dashed arrow. Therefore, the positions L for electrodes 22, 23, as previously described for the device 50. _ACT The measurement module 51 measures the actual torque Mn of the drive mechanism 26 during the welding process, as previously described for the device 50A. _ACT The combination of measurements is feasible. Here, if the actual force F S_ACTIf the values ​​produced by these devices differ from each other or fall outside a predetermined tolerance range, then it may be necessary to assign a higher weight to the measurement of one of the devices 50 and 50A. This allows for a better and / or more reliable generation of the actual force F. S_ACT The force value. Furthermore, the devices 50 and 50A can be configured to, if the actual force F S_ACT If the values ​​generated are different from each other or fall outside the predetermined tolerance range, the welding process will be interrupted and a corresponding notification 48 will be output.

[0128] According to the fourth embodiment, the welding tool 21 is configured as an X-shaped clamp. The electrodes 22 and 23 are preferably configured as water-cooled electrode rods in the aforementioned welding clamp.

[0129] All previously described design options for the welding equipment 2, welding control system 10, devices 50, 50A, setting module 11, force adjustment module 12, and method can be used individually or in all feasible combinations. In particular, all features and / or functions of the foregoing embodiments can be arbitrarily combined. As a supplementary option, the following modifications are particularly conceivable.

[0130] The components shown in the accompanying drawings are schematically illustrated, and their exact form may differ from that shown in the accompanying drawings, provided that their previously described functions are ensured.

[0131] It is conceivable that at least one of the devices 50, 50A is not configured as a separate device 50, 50A, but is part of the welding control system 10.

[0132] The welding control system 10 enables the parameterization of simulated regulators. Regulator parameterization can be performed for the force regulator and / or speed regulator. Specifically, the force regulation module 12 can output at least one speed rating n_S to the drive mechanism 26 of the welding tool 21, so that the speed regulator of the drive mechanism 26 can adjust the drive of the welding tool 21 to apply a force F. S (t), F S_ACT As an alternative, adjusting other physical parameters is also feasible.

[0133] The simulation of the regulator parameterization can be supported using MATLAB Simulink.

[0134] The welding tool 21 is not necessarily implemented as a welding clamp, but can have only one welding electrode 22 or 23, etc.

[0135] As an alternative, force F can be applied on both sides, that is, not only at electrode 22 or only at electrode 23, but through both electrodes 22 and 23.S The corresponding import.

[0136] Alternatively, it is feasible to use other regulators 121 as PD regulators. In this case, the other regulator parameters of the regulators 121 are changed to avoid force F. S Oscillations. Here, as an alternative, multiple regulators 121 can be connected sequentially. If, for example, a two-point regulator is used instead of a PD regulator, a solution with less dynamics and less favorable regulation technology is provided compared to the previously described solution using a PD regulator. Here, the appropriate parameters for the two-point regulator must then be matched to avoid oscillations.

Claims

1. A device (50, 50A) for a welding control system (10), comprising a means for measuring at least one welding tool parameter (A B The measurement module (51) for M_B) and the welding tool parameters (A) measured by the measurement module (51) B The actual force (F) generated in M_B during the welding process using welding tool (21) is generated. S_ACT The force value generation module (52) of the welding tool, wherein at least one welding tool parameter (A) B The force (M_B) depends on the driving of the welding tool (21) relative to at least one component (5, 6) during the welding process, wherein the force value generation module (52) is configured to generate the actual force (F) using a model (511) of the welding tool (21). S_ACT The model (511) models the welding tool (21) as a spring (211, 212, 213) and has at least one spring parameter (k_E, Tt) that determines the spring (211, 212, 213), wherein the at least one spring parameter (k_E, Tt) is an equivalent spring constant (k_E), the equivalent spring constant having at least one spring constant (k_F1, kF2) with respect to the mechanical properties of the welding tool (21) and a spring constant (k_F3) with respect to the properties of the at least one component (5, 6) to be welded.

2. The apparatus (50, 50A) according to claim 1, wherein the at least one spring parameter (k_E, Tt) is the dead time (Tt), when a force (F) is applied to the welding tool (21). S The dead time (Tt) delay is used to establish the force formation for the welded connection (7) when (t)).

3. The apparatus (50, 50A) according to claim 1, wherein the force value generating module (52) is configured to take into account the variation of the at least one spring parameter (k_E, Tt) during the welding process.

4. The apparatus (50, 50A) according to any one of claims 1 to 3, wherein the at least one welding tool parameter is the arm bending (A) of the welding tool (21). B The arm bending is the actual position (L) of at least one electrode (22, 23) of the welding tool (21). ACT The function of ), and / or wherein the at least one welding tool parameter is the acceleration torque (M_B) of at least one electrode (22, 23) of the welding tool (21), and the acceleration torque (M_B) is the actual rotational speed (n_) of the drive mechanism (26) for driving at least one electrode (22, 23) of the welding tool (21). ACT The function of ).

5. The apparatus (50, 50A) according to claim 4, wherein the force value generating module (52) is configured to generate an actual force (F) S_ACT Considering the change in force (Fs(t)) that occurs during welding with the welding tool (21), and the change in force (Fs(t)) is due to the thermal expansion of the at least one component (5, 6) and / or due to the at least one electrode (22, 23) sinking into the at least one component (5, 6) at the melting position and / or due to welding spatter (8).

6. A welding control system (10) for a welding tool (21), comprising: a force adjustment module (12) for adjusting the variation curve of a force (Fs(t)), wherein at least one electrode (22, 23) of the welding tool (21) applies the force (Fs(t)) to at least one component (5, 6) when establishing a weld joint (7); and a device (50, 50A) according to any one of claims 1 to 5, wherein the force adjustment module (12) is connected to the device (50, 50A) such that the force adjustment module (12) applies the actual force (Fs(t)) generated by the device (50, 50A) to the welding tool (21). S_ACT The curve of the change of the force (Fs(t)) is used to adjust the curve of the change of the force.

7. The welding control system (10) according to claim 6, wherein the device (50, 50A) is configured to measure, during the welding process performed with the welding tool (21), different welding tool parameters (A) are defined by the measuring module (51). B The force (F) generated by M_B in the same time (t) S The difference between the actual values ​​of (t) and the device (50, 50A) is configured to notify the welding control system (10) that the welding process should be interrupted when the measured difference is numerically outside a predetermined tolerance range.

8. The welding control system (10) according to claim 6 or 7, further comprising a setting module (11) for evaluating the adjustment of the force adjustment module (12), wherein the setting module (11) is configured to model the welding tool (21) as a spring (211, 212, 213) and set at least one regulator parameter (120) of the force adjustment module (12) based on at least one parameter (k_E, Tt) of the spring (211, 212, 213).

9. Welding equipment (2), comprising: a welding tool (21) having at least one electrode (22, 23) for establishing a weld joint (7) on at least one component (5, 6); a welding control system (10) for controlling the weld joint (7) established by said welding tool (21); and a device (50, 50A) according to any one of claims 1 to 5, wherein, The welding control system (10) has a force adjustment module (12) for adjusting the variation curve of the force (Fs(t)), wherein the force adjustment module (12) is connected to the device (50, 50A) such that the force adjustment module (12) adjusts the actual force (Fs(t)) generated by the device (50, 50A). S_ACT ) used to adjust the force (F) S The curve of the change of (t)).

10. The welding apparatus (2) according to claim 9, wherein the welding tool (21) is a resistance welding tool configured as a welding clamp having two electrodes (22, 23).

11. A method for generating a force value when controlling a welding tool (21), said method being carried out by means of an apparatus (50, 50A) for a welding control system (10) according to any one of claims 1 to 5 and comprising the steps of: measuring (S4) at least one welding tool parameter (A) using a measuring module (51). B The welding tool parameters depend on the driving of the welding tool (21) relative to at least one component (5, 6) during welding with the welding tool (21); and the welding tool parameters (A) measured by the measuring module (51) are obtained by the force value generation module (52). B The actual force (F) generated in M_B) is (S5). S_ACT The actual force (R) S_ACT During welding using the welding tool (21), the force generation module (52) generates the actual force (F) using a model (511) of the welding tool (21). S_ACT ).

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