Method and system with volatility-based control of a flow-hole-forming screw

Abstract

A method for installing a flow drilling screw (FDS) into a substrate includes engaging the FDS with an automated tool and operating the tool at a first setting to screw the FDS into the substrate. The first setting rotates the FDS at a first speed and applies a first axial feed force. The first setting causes the substrate to flow to allow the FDS to penetrate the substrate. The method includes sensing axial position data of the FDS via a sensor while operating the automated tool and calculating, via a controller, volatility of the axial position data. The method includes switching the automated tool from the first setting to a second setting in response to the volatility. The second setting rotates the FDS at a second speed and applies a second axial feed force to the FDS.The second speed is lower than the first speed.

Description

AREA

[0001] The present disclosure relates to a method and system for installing a flow hole forming screw. GENERAL STATE OF THE ART

[0002] The statements in this section merely provide background information concerning the present disclosure and may not constitute prior art.

[0003] A flow drill screw (FDS) is a specific type of screw used to create a threaded connection between multiple substrates, one of which is a bottom substrate, without the use of part preparation such as tapping or punching a hole in the bottom substrate. The bottom substrate is typically metal, and the total number of substrates is typically two to four, although other numbers can be used. The top substrate(s) may or may not have a pre-formed through-hole.

[0004] A typical FDS has a distal end portion that lacks threads or cutting edges and is configured to penetrate the substrate by locally heating the substrate with heat generated by rotational friction and axial pressure on the FDS. As the FDS penetrates the substrate, it forms a thread in the substrate.

[0005] In a typical FDS process, an automatic tool is controlled to rotate the FDS at a high rate of revolutions per minute (rpm) while applying an axial force toward the substrate. The typical automatic FDS tool does not directly control the axial position. This high-rpm force creates the friction that heats the substrate and is maintained until the automatic tool detects a trigger condition based on real-time measurement data, corresponding to the onset of penetration. Immediately after detecting this trigger condition, the automatic tool controller signals the automatic tool to decrease the rpm and force. Thus, the automatic tool decreases the rpm and force before the thread-forming portion of the FDS penetrates the substrate, allowing threading and tightening of the FDS against the substrate to occur at lower rpm and lower force.It is generally understood in the art that the RPM and force should be reduced once penetration is achieved, but not before. It is generally recognized in the art that if the FDS has not fully penetrated before the RPM and force are reduced, there is a high probability that the FDS will ultimately not penetrate the lower substrate at all. This is because the lower RPM and / or force will not generate sufficient heat or force to continue penetration and deformation of the metal. Furthermore, those skilled in the art generally believe that it is important to reduce the RPM and force before the thread-forming portion penetrates the lower substrate so that there is sufficient process control both as process completion approaches (e.g.,This includes both allowing the substrate to cool slightly before the thread-forming section penetrates the substrate and the bushing area. Furthermore, it is generally considered critical that the rpm and force at the typical ramp-down point of the process be sufficiently low so that they have an acceptable ability to stop the process upon reaching a target torque value and not over-torque and over-tighten the joint.

[0006] It is important that the torque applied to the FDS during the penetration portion of the installation process does not exceed the rated torque value of the FDS.

[0007] The trigger condition is typically a threshold for an axial position (i.e., depth) or an axial velocity (i.e., depth gradient).

[0008] The teachings of the present disclosure address these and other problems in installing an FDS in a substrate. SUMMARY

[0009] This section provides a general summary of the disclosure and is not a comprehensive disclosure of its full scope or all of its features.

[0010] In one form, the present disclosure provides a method for installing a flow-drilling screw (FDS) into a substrate, including engaging the FDS with an automated tool. The method includes operating the automated tool at a first setting to screw the FDS into the substrate by causing the substrate to flow to allow the FDS to penetrate the substrate. The first setting is configured to rotate the FDS at a first speed and apply a first axial feed force to the FDS. The first setting is configured to cause the substrate to flow to allow the FDS to penetrate the substrate. The method includes acquiring axial position data of the FDS via a sensor while operating the automated tool. The method includes calculating a volatility of the axial position data of the FDS via a controller.The method involves switching the automatic tool from the first setting to a second setting in response to the volatility. The second setting is configured to rotate the FDS at a second speed and apply a second axial feed force to the FDS. The second speed is lower than the first speed.

[0011] In variations of the method of the preceding paragraph, which may be implemented individually or in any combination thereof: in response to the controller determining that a trigger condition has occurred, the controller switches the automatic tool from the first setting to the second setting, the trigger condition including at least one of a value of the volatility exceeding a predetermined volatility value and the value of the volatility being within a predetermined range of a maximum volatility value; the predetermined volatility value being greater than or equal to 0.5 mm; the controller is configured to wait a predetermined delay time after the controller determines that the trigger condition has occurred and before switching the automatic tool from the first setting to the second setting; the value is an average of the volatility over a subset of time;the controller switches the automatic tool from the first setting to the second setting in response to a maximum volatility value being reached; the method further includes calculating a forecast maximum volatility value, wherein the controller switches the automatic tool from the first setting to the second setting based on the forecast maximum volatility value; the controller switches the automatic tool from the first setting to the second setting based on the maximum volatility value being forecast but before the maximum volatility value is reached; the controller calculates the volatility using at least one of a true range (TR) formula and a standard deviation formula.;

[0012] In another form, the present disclosure provides a method for installing a flow-drilling screw (FDS) into a substrate, including engaging the FDS with an automated tool. The method includes operating the automated tool at a first setting to screw the FDS into the substrate by causing the substrate to flow to allow the FDS to penetrate the substrate. The first setting is configured to rotate the FDS at a first speed and apply a first axial feed force to the FDS. The first setting is configured to cause the substrate to flow to allow the FDS to penetrate the substrate. The method includes acquiring axial position data of the FDS via a sensor while operating the automated tool.The method includes calculating, via a controller, a volatility of the axial position data of the FDS. The method includes switching, via the controller, the automatic tool from the first setting to a second setting in response to the controller determining that a trigger condition has occurred. The trigger condition includes at least one of the following: a value of the volatility exceeding a predetermined volatility value; and the value of the volatility being within a predetermined range of a maximum volatility value. The second setting is configured to rotate the FDS at a second speed and apply a second axial feed force to the FDS. The second speed is less than the first speed.

[0013] In variations of the method of the preceding paragraph, which may be implemented individually or in any combination thereof: the triggering condition includes the value of volatility exceeding the predetermined volatility value, where the predetermined volatility value is greater than or equal to 0.5 mm; the triggering condition includes the value of volatility being within a predetermined range of a maximum volatility value; in response to the maximum volatility value being reached, the controller switches the automatic tool from the first setting to the second setting; the method further includes calculating a forecast maximum volatility value, where the controller switches the automatic tool from the first setting to the second setting based on the forecast maximum volatility value; the value is an average of the volatility over a subset of time.

[0014] In yet another form, the present disclosure provides a system for installing a flow-drilling screw (FDS), including a drive unit, at least one sensor, and a controller. The drive unit is configured to rotate the FDS about an axis at a speed while applying an axial feed force to the FDS to screw the FDS through at least one substrate. The at least one sensor is configured to acquire axial position data of the FDS. The controller is in communication with the at least one sensor. The controller is configured to determine the volatility of the axial position data of the FDS and to change the speed and the axial feed force in response to a trigger condition being reached.The trigger condition includes at least one of the following: a volatility value exceeds a predetermined volatility value; and the volatility value is within a predetermined range of a maximum volatility value.

[0015] In variations of the system of the preceding paragraph, which may be implemented individually or in any combination thereof: the trigger condition includes the value of volatility exceeding the predetermined volatility value, where the predetermined volatility value is greater than or equal to 0.5 mm; the trigger condition includes the value of volatility being within a predetermined range of a maximum volatility value; the value is an average of volatility over a subset of time; the controller is configured to determine volatility using at least one of a true range (TR) formula and a standard deviation formula.

[0016] Further areas of applicability will become apparent from the description provided herein. It is understood that the description and specific examples are for illustrative purposes only and are not intended to limit the scope of the present disclosure. DRAWINGS

[0017] In order that the disclosure may be fully understood, various forms thereof will now be described by way of example with reference to the accompanying drawings, in which: Fig. 1 is a side view of an exemplary flow drilling screw (FDS); Fig. 2 is a series of consecutive phases of an FDS from Fig. 1 during an installation process according to the teachings of the present disclosure; Fig. 3 is a diagram illustrating torque and screw position in an installation process of a flow hole forming screw according to the teachings of the present disclosure; Fig. 4 is a graph illustrating axial velocity, screw position, and an erroneous screw position measurement for a flow hole forming screw installation process according to the teachings of the present disclosure; Fig. Figure 5 is a detailed view of a section of the diagram from Fig. 4, which illustrates how erroneous screw position measurements can be corrected by axial velocity control; Fig. 6 is a graph illustrating a data history for a flow hole forming screw installation process according to the teachings of the present disclosure, showing screw velocity versus volatility of screw position data calculated using two different algorithms according to the teachings of the present disclosure; Fig. Figure 7 is a detailed view of a section of the diagram from Fig. 6; and Fig. 8 is a flow diagram illustrating a method for installing a flow hole forming screw according to the teachings of the present disclosure.

[0018] The drawings described in this document are for illustrative purposes only and are not intended to limit the scope of the present disclosure in any way. DETAILED DESCRIPTION

[0019] The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that corresponding reference characters indicate like or corresponding parts and features throughout the drawings.

[0020] Related to Fig. 1, a typical FDS 10 is shown and includes a head 14 and a shank 18 disposed about a rotational axis 22. The head 14 includes a clamping portion 26 and a tool-engaging portion 30. The clamping portion 26 extends radially outward from the shank 18. The tool-engaging portion 30 is configured to be gripped by an automatic tool to rotate the FDS 10 about its rotational axis 22. The shank 18 extends in an axial direction from the clamping portion 26 to a tip 34. Between the tip 34 and the clamping portion 26 are a threaded portion 38, a thread-forming portion 42, a cylindrical portion 46, and an end portion 50. The tip 34 is typically rounded, relatively smooth, and relatively blunt, as shown, although some typical FDS may have a more pointed tip.The end portion 50 includes the tip 34 and tapers radially outward toward the cylindrical portion 46. The end portion 50 and the cylindrical portion 46 lack threads. In some forms, the cylindrical portion 46 has a constant diameter. In other forms, the cylindrical portion 46 has a diameter that increases more gradually than the end portion 50. The threaded portion 38 has at least one complete thread form 54 disposed about the axis 22. The thread-forming portion 42 is located axially between the cylindrical portion 46 and the threaded portion 38 and has at least one partial thread form 58 that is coincident with the at least one complete thread form 54, but tapers radially inward from the complete thread form 54 toward the cylindrical portion 46.In other words, the thread-forming portion 42 has a partial depth thread form whose diameter (i.e., thread diameter) becomes narrower with increasing distance from the threaded portion 38. In some forms not shown, a typical FDS may include a second cylindrical portion between the clamping portion 26 and the threaded portion 38.

[0021] Related to the Fig. 1 and Fig. 2 illustrates successive phases or states (labeled 1-6) of the FDS 10 during an installation process by an installation tool 110. The tool 110 is an automated tool that includes a driver 114, one or more sensors 118 (shown only in Phase 1 for ease of illustration), and a controller 122 (shown only in Phase 1 for ease of illustration). The driver 114 is configured to engage the tool engagement portion 30 of the FDS 10 to rotate the FDS 10 about its rotational axis 22 while applying an axial force toward a first substrate 210. The controller 122 is in communication with the driver 114 and the sensors 118 and is configured to control the operation of the driver 114 and receive inputs from the sensors 118.

[0022] The first substrate 210 may be any suitable material formed using any suitable process. In one form, the first substrate 210 is aluminum or an aluminum alloy. In another form, the first substrate 210 is magnesium or a magnesium alloy. In yet another form, the first substrate 210 is steel or a steel alloy. In yet another form, the first substrate 210 is a composite material. In some forms, the first substrate 210 may be a stamped sheet of material. In other forms, the first substrate 210 may be a casting. In still other forms, the first substrate 210 may be an extruded part. In still other forms, the first substrate 210 may be wrought.

[0023] Although not specifically shown, the screwdriver 114 includes a motor (e.g., an electric motor, a hydraulic motor, or a pneumatic motor) configured to provide rotation and controlled by the controller 122. Although not specifically shown, the screwdriver 114 also includes an actuator that can be actuated by any suitable power source (e.g., electrical, hydraulic, or pneumatic power) to apply the axial force. The actuator is controlled by the controller 122. In one form, the actuator is a pneumatic actuator (e.g., a pneumatic cylinder) to apply the axial force. In one form, the screwdriver 114 may optionally be disposed on a robot arm (not shown) or a base (not shown), and the controller 122 may be configured to control movement of the robot arm or base.

[0024] In the first phase, the FDS 10 is rotated while an axial force is applied to the FDS 10 in the axial direction toward the first substrate 210. In this first or initial phase, the first substrate 210 does not have any through-hole at the location where the FDS 10 is to be installed.

[0025] In the provided example, the first substrate 210 is a bottom substrate and a second substrate 214 is an upper substrate disposed on top of the first substrate 210 and configured to be clamped to the first substrate 210 by the clamping portion 26 of the FDS 10. In the provided example, the second substrate 214 defines a preformed bore 218 having a diameter larger than the shaft 18 but smaller than the clamping portion 26 so that the clamping portion 26 can clamp the second substrate 214 against the first substrate 210. While only one second substrate 214 is illustrated, additional substrates may be used. For example, in some configurations not specifically shown, the FDS 10 may clamp one, two, three, four, or more additional substrates to the first substrate 210 in addition to the second substrate 214.These additional substrates may optionally have preformed through-holes, or the FDS may form the hole through them. In the case of the device shown in . Fig. In the example shown in Figure 2, the FDS 10 completely penetrates the first substrate 210 in the last phase 6.

[0026] While the first substrate 210 of the representation in Fig. 2 is thinner than the second substrate 214, the first substrate 210 may be thicker than the second substrate 214 in another form not specifically shown.

[0027] In another alternative configuration, not specifically shown, the first substrate 210 may be the upper substrate and a second substrate may be the lower substrate, but without the preformed bore 218 ( Fig. 2) the second substrate 214. In this alternative configuration, the FDS 10 may pierce the first substrate 210 and the second substrate to clamp the first substrate 210 to the second substrate.

[0028] In yet another alternative configuration, not specifically illustrated, a second substrate may be omitted entirely, and the FDS 10 may be connected only to the first substrate 210. In some such forms, the FDS 10 may include a connection feature (not shown, e.g., a hook, a loop, a magnet, a surface for receiving adhesive, etc.) so that a mating feature on another component can be coupled to the FDS 10 after the FDS 10 has been attached to the first substrate 210.

[0029] With further reference to the Fig. 1 and Fig. 2, during the first phase 1, also referred to as the heating phase, the rotational speed and axial force of the tool 110 are configured to generate friction at the tip 34 to locally heat the substrate to a degree sufficient to cause the substrate to melt or soften to a flowable state. Generally, the tool 110 continues to rotate the FDS 10 and apply axial pressure thereto until the FDS 10 is fully tightened in the final (e.g., sixth) phase 6, also referred to as the tightening phase.

[0030] During Phase 2, also referred to as the penetration phase, the end portion 50 of the FDS 10 begins to penetrate the first substrate 210, but the cylindrical portion 46 has not penetrated the first substrate 210. During Phase 3, the cylindrical portion begins to penetrate the first substrate 210, but the thread-forming portion 42 has not penetrated the first substrate 210. Phase 3 is also referred to as the hole formation phase because this is the phase in which the core diameter of the hole is formed in the first substrate 210. It should be understood that while during Phase 3 the tip 34 is shown to have completely penetrated the first substrate 210, depending on the thickness of the first substrate 210, the tip 34 may still be within the first substrate 210. At phase 4, the thread-forming portion 42 begins to penetrate the first substrate 210, but the threaded portion 38 has not penetrated the first substrate 210.Phase 4 is also referred to as the thread forming phase because the thread forming portion 42 develops the thread during this phase. During Phase 5, the threaded portion 38 begins to penetrate the first substrate 210. During Phase 5, also referred to as the screw-in phase, the threaded portion 38 screws into the thread formed by the thread forming portion 42 and the FDS 10 advances axially into the first substrate 210 until the clamping portion 26 engages the second substrate 214 (or, in the case where the second substrate is located below the first substrate 210, the clamping portion 26 engages the first substrate 210) to begin the final Phase 6. During Phase 6, also referred to as the tightening phase or final tightening phase, the FDS 10 is tightened until it is fully tightened.

[0031] In some forms, the sensors 118 may detect a predetermined final trip condition, and the controller 122 controls the driver 114 to tighten the FDS 10 to the predetermined final trip condition. In one form, the sensors 118 may include a torque sensor, and the final trip condition may be a predetermined final torque value. The predetermined final torque value is less than a torsional strength value of the FDS 10. In another form, the sensors 118 may include a depth or position sensor to detect position data, and the predetermined final trip condition may be a depth or position of the FDS 10 and / or a predetermined torque value.

[0032] Related to Fig. 3 illustrates the torque and axial screw position (i.e., depth) over time during an installation process of an FDS 10. In this graph, the maximum screw position (i.e., at line 410) refers to the position where the tip 34 of the FDS 10 initially contacts the first substrate 210, and the 0 mm (zero mm) screw position refers to the final position at which the clamping portion 26 clamps the second substrate 214 against the first substrate 210 (or, in the form where the second substrate is below the first substrate 210, the clamping portion 26 engages the first substrate 210).

[0033] Related to the Fig. 2 and Fig. 3, phase 1 (i.e., the heating phase) begins at line 410 and continues with line 414. During this phase, the torque increases, but the axial position of the FDS 10 remains stationary while heat builds up.

[0034] Phase 2 (i.e., the penetration phase) begins at line 414. During this phase, the torque continues to increase to a first peak 418, and the axial position of the FDS 10 slowly moves downward (i.e., toward zero mm) as the tip 34 begins to penetrate the first substrate 210. As illustrated, the axial position of the FDS 10 may begin to slowly move downward as the tip 34 continues to penetrate the first substrate 210, as the first substrate 210 continues to soften due to heat buildup.

[0035] Phase 3 (i.e., the hole formation phase) begins at line 422. During this phase, the torque drops and the axial position of the FDS 10 moves rapidly downward as the cylindrical portion 46 penetrates the first substrate 210.

[0036] Phase 4 (i.e., the thread forming phase) begins at line 426. During this phase, the torque increases rapidly to a second peak 430 and the axial position of the FDS 10 continues to move downward, albeit at a slower rate than during Phase 3, as the thread forming portion 42 penetrates the first substrate 210 and forms a thread in the first substrate 210.

[0037] Phase 5 (i.e., the screw-in phase) begins at line 434. During this phase, the torque decreases to a generally steady state while the axial position of the FDS 10 continues to move downward via the mating action of the threaded portion 38 and the thread formed in the first substrate 210 by the thread-forming portion 42 during Phase 4.

[0038] Phase 6 (i.e., the final tightening phase) begins at line 438. During this phase, the torque increases steeply while the axial position of the FDS 10 remains essentially at zero mm. The torque increases until the final trip condition is met and the controller 122 stops the rotation of the screwdriver 114.

[0039] At the beginning of Phase 1 (line 410), the tool 110 is controlled to operate at a first setting, where the tool 110 is controlled to operate at a first speed and a first axial feed force. At any time between the beginning of Phase 3 (line 422) and the beginning of Phase 6 (line 438), the tool 110 is controlled to switch from the first setting to a second setting, where the tool 110 is controlled to operate at a second rpm and a second axial feed force (which may or may not be the same as the first axial feed force). The first speed is also referred to herein as high speed and may range from 1,500 to 11,000 rpm, inclusive. In one form, the first speed is particularly in the range from 2,000 to 8,000 rpm, inclusive.In another form, the first speed is specifically in the range from 6,000 to 11,000 rpm inclusive. The first axial feed force is also referred to herein as the high axial feed force and is in the range from 0.5 to 2.5 kilonewtons (kN). In one form, the first axial feed force may be in the range from 1 to 2 kN. The second speed is also referred to herein as the low speed and is in the range from 500 to 4,000 rpm inclusive. In one form, the second speed may be within this range but lower than the first speed, although other configurations may be used. The second axial feed force is also referred to herein as the low axial feed force and is in the range from 0.25 to 1.25 kN inclusive.In one form, the second axial feed force may be within this range but less than the first axial feed force, although other configurations may be used. For example, in another form, the second axial feed force may be equal to or greater than the first axial feed force.

[0040] Related to Fig. 4 illustrates two sets of axial screw position (i.e., depth) data for the same screw over time during an installation process of the FDS 10. A first position curve 510 is formed by a first set of screw position data measured by the sensors 118. A second position curve 514 is formed by a second set of screw position data measured by the sensors 118. The difference 518 in the measured screw position data may be due to any number of factors (e.g., calibration errors between two position sensors 118).

[0041] Fig. 4 also illustrates the axial speed 522 of the FDS 10 over time during the installation process. As shown in Fig. 4, the axial velocity 522 is the same for both position curves 510, 514. It has been found that the axial velocity is effectively the same or has a very small difference even when the two position curves are generated using the same sensor 118 but for the same general process with a subsequent screw (e.g., the difference 518 in the measured position data being due to other factors, such as dimensional tolerances in the FDS 10, tolerances in the first substrate 210, and / or tolerances in the second substrate 214).

[0042] With reference to Fig. 5, if a specific axial position value (e.g., depth) is used as the trigger point (e.g., threshold 610) to switch from the first setting (e.g., high speed and high axial feed force) to the second setting (e.g., low speed and low axial feed force), an error (represented by a distance 614 between the time the first position data 510 crosses this value 610 and the time the second position data 514 crosses this value 610) may occur. However, if the threshold 610 is a specific axial velocity value instead of an axial position value, it has been found that this error is eliminated (as in the illustrated example) or greatly reduced while ensuring that the process can function as intended.

[0043] However, it has been found that due to many factors (e.g., signal propagation times, signal processing times, sampling speed, angular momentum in the system), these typical trigger conditions (e.g., position threshold or axial velocity threshold) can ultimately be a lagging indicator of the true position of the FDS 10, especially when smoothed axial velocity data is used. In other words, by the time the actual rotation and axial force of the FDS 10 are reduced (compared to the time the controller sends the signal(s) to reduce the rotation and axial force), the FDS 10 may already have exceeded the most desirable axial position relative to the substrate(s). Furthermore, when raw axial velocity data is used, this data can be very noisy, i.e., not produce a smooth data curve.This may also increase the variability of the true position of the FDS with respect to when the axial velocity threshold is triggered by the raw axial velocity data.

[0044] Nonetheless, axial velocity may still be a lagging indicator of the actual characteristics of the FDS 10, as discussed in more detail in commonly assigned U.S. patent application Ser. No. 18 / 466,775, entitled "Method and System with Acceleration Based Flow Drill Screw Control," filed September 13, 2023, which is incorporated herein by reference in its entirety.

[0045] With reference to Fig. 6 and Fig. 7 is the control 122 ( Fig. 2) configured to detect in real time a volatility of the axial position data (e.g. the first position data 510 or the second position data 514 from Fig. 3-5) detected by the sensor 118 ( Fig. 2). The volatility may be calculated using any suitable algorithm for calculating the volatility of a data set. Thus, the controller may output a volatility data set. In one form, the controller 122 may calculate the volatility of the axial position data using a standard deviation algorithm (ST.DEV function or formula) on the axial position data, as indicated by trace 610. In another form, the controller 122 may calculate the volatility of the axial position data using a true range algorithm (TR function or formula) on the axial position data, as indicated by trace 614. While standard deviation and true range are shown, other volatility algorithms may be used.

[0046] The volatility algorithm can use any suitable lookback period. In one form, the volatility algorithm can use a lookback period of 10 ms, although other periods can be used.

[0047] Surprisingly, as best in Fig. 7, the calculated volatility data set (e.g., trace 610 or 614) provides an identifiable signal change that was found to correlate repeatedly with the process conditions (e.g., the phase of installation) during the installation of the FDS 10 ( Fig. 1 and Fig. 2). The volatility algorithms may also provide a smoother data curve compared to the raw velocity data (trace 612), which may lead to more consistent results and the ability to more accurately detect a change in the data curve (e.g., from initially steady-state conditions) earlier than other data forms. As can be seen at least in trace 614 of the true-range algorithm, some of these volatility algorithms may also provide an identifiable signal change earlier than other data sources, such as the smoothed velocity data (trace 616). Thus, the controller 122 ( Fig. 2) be configured to check in real time when the volatility data reaches a predetermined threshold volatility value.

[0048] In the provided example, this predetermined volatility threshold for the true range algorithm data (e.g., history 614) may be greater than or equal to 0.5 mm (e.g., threshold 618), although other thresholds may be used, including lower or higher values ​​depending on where a repeatable and identifiable signal change exists for a particular FDS application. In the provided example, the predetermined volatility threshold for the standard deviation algorithm may be greater than or equal to 0.25 mm (e.g., threshold 622), although other thresholds may be used, including lower or higher values ​​depending on where a repeatable and identifiable signal change exists for a particular FDS application.

[0049] This threshold volatility value can provide a more accurate and repeatable trigger while also providing a leading indicator. In other words, screw position volatility data can provide a curve that can repeatedly generate an identifiable threshold trigger that occurs early enough in the installation process for the controller 122 to respond to this threshold, compensating for delays in data processing, signal propagation, and the physical momentum of components. In other words, setting the trigger to the volatility threshold results in a much earlier trigger for the controller 122 to send control signals, allowing the FDS 10 to actually physically reach the second rotational speed and second axial feed force sooner than would normally be possible with axial position thresholds or some other data.

[0050] The value of the threshold (also called trigger value) at line 618 or 622 is in Fig. 7 is shown for explanatory purposes and can be selected for volatility values ​​other than those shown. The actual volatility threshold may also vary depending on the data collection processes implemented, the type of volatility algorithm used, and, if applicable, the smoothing processes implemented. For example, different data collection and / or volatility algorithm and / or smoothing processes may change the values ​​of the data set used, and the threshold can be selected accordingly. Likewise, the values ​​of the data gradients or curves shown in the diagrams in the figures are also shown for explanatory purposes and may vary depending on the data collection and / or smoothing processes used.

[0051] In one form, the controller 122 may calculate the volatility directly from the raw axial position data. In another form, the controller 122 may apply a smoothing filter to the raw axial position data and then calculate the volatility using the smoothed axial position data. In another form, the controller 122 may apply a smoothing filter to the calculated volatility data without first smoothing the raw axial position data before calculating the volatility. In yet another form, the controller 122 may apply a smoothing filter to the calculated volatility data after first smoothing the raw axial position data before calculating the volatility.

[0052] In one form, the controller 122 analyzes each volatility data value individually to determine whether it is at or above the volatility threshold. In another form, the controller 122 calculates an average of the volatility values ​​over a subset of time and analyzes this average to determine whether it is at or above the volatility threshold.

[0053] In one form, the volatility threshold 618 may be greater than or equal to 0.25 mm, although other thresholds may be used depending on the data collection and / or the volatility algorithm and / or the smoothing processes used (e.g., 0.5 mm or 1 mm or anywhere in the range of 0.25 mm to 4 mm).

[0054] In one configuration of this form, the controller 122 sends control signals to switch to the second setting immediately after determining that the volatility data (e.g., 610 or 614) has reached or exceeded the volatility threshold 618. In another configuration of this form, the controller 122 starts a predetermined time delay immediately after determining that the volatility data (e.g., 610 or 614) has reached or exceeded the volatility threshold 618 and then sends control signals to switch to the second setting immediately after the end of the time delay. In some forms, this time delay may be between 1 and 30 ms, inclusive.

[0055] In yet another configuration of this form, the controller 122 does not use a predetermined time delay and instead uses a predetermined axial position delay. In other words, the controller 122 begins analyzing the measured axial position data immediately after determining that the volatility data (e.g., 610 or 614) has reached or exceeded the volatility threshold 618, and then sends control signals to switch to the second setting immediately after the axial position data shows that the FDS 10 has moved a predetermined axial distance past the volatility threshold 618. In some forms, this predetermined axial distance may be between 0.5 and 10 mm, inclusive. In some forms, this predetermined axial distance may be between 0.5 and 2 mm, inclusive. In some forms, this predetermined axial distance may be between 0.5 and 1 mm, inclusive.

[0056] In another form, which is not specifically shown, the volatility threshold 618 can be set to represent the maximum volatility reached (e.g. at point 626 or 630 from Fig. 7), or may be set based on a determination of the maximum volatility to be achieved. In other words, the controller 122 may be configured to switch to the second setting after it is determined that the maximum volatility (e.g., point 626 or 630) has been reached. In one configuration of this form, the controller 122 may switch immediately after it is determined that the maximum volatility has been reached. In another configuration, the controller 122 may be configured to switch immediately after a predetermined time delay after the maximum volatility has been reached. In another configuration, the controller 122 may be configured to switch immediately after a predetermined delay in the axial position after the maximum volatility has been reached.

[0057] The controller 122 may determine the maximum volatility in any suitable manner, including, but not limited to, any of the following examples individually or in any suitable combination thereof. In one example, the controller 122 compares each volatility value to subsequent volatility values ​​and determines that the maximum value is the value below which at least two subsequent volatility values ​​are. In another example, the controller 122 considers the derivative of the volatility data values ​​in real time and determines that the maximum volatility is the value at which the derivative (i.e., slope) of the volatility curve (e.g., 610 or 614) begins to become negative.

[0058] In another example, controller 122 may fit a mathematical model (e.g., a moving average) to the volatility data and predict when the volatility will reach its maximum. In the example where controller 122 predicts maximum volatility, controller 122 may switch to the second setting a predetermined time or position before that maximum, thus compensating for delays in signal processing, momentum, etc. In other words, volatility threshold 618 may be within a predetermined range of the maximum volatility value.

[0059] With reference to Fig. 2 and Fig. 8 illustrates an installation process or method 910. The installation method 910 includes step 914. At step 914, the substrate or substrates (e.g., the first substrate 210 and the second substrate 214) are positioned. The method 910 then proceeds to step 918.

[0060] At step 918, the controller 122 positions the driver 114 to engage the FDS 10 and such that the tip 34 of the FDS 10 contacts the first substrate 210 at a predetermined location on the first substrate 210. The method 910 then proceeds to step 922.

[0061] The beginning of step 922 corresponds to line 410 ( Fig. 4). At step 922, the controller 122 operates the automatic tool 110 at a first setting. At the first setting, the controller 122 controls the driver 114 to rotate at the first speed and apply the first axial force to the FDS 10. In other words, the controller 122 sends signals to the driver 114 to cause the driver 114 to rotate the FDS 10 at the first speed while pressing the FDS 10 against the first substrate 210 with a first axial feed force.

[0062] While slight variations may occur, the control signals from controller 122 are initially configured to operate the screwdriver at a constant speed and axial feed force during step 922.

[0063] As represented by step 916, while the screwdriver 114 is applying the first speed and the first axial feed force, the sensor(s) 118 detects a depth or position of the FDS 10. The controller 122 receives signals from the sensor(s) 118.

[0064] At step 920, the controller 122 calculates the volatility data (e.g., the volatility data 610 or 614), as discussed above. As discussed above, the controller 122 may optionally apply a smoothing filter to the directly acquired position data and / or the volatility data.

[0065] Referring again to the provided example, at step 926, the controller 122 determines whether a predetermined first trigger condition is met based on the volatility data from step 920. The first trigger condition of the method 910 is a threshold volatility value, such as the threshold volatility value 618 ( Fig. 7) and / or those otherwise discussed above.

[0066] The controller 122 continues to operate the screwdriver 114 at the first speed and the first axial feed force until the first trigger condition is met. The detection of the first trigger condition is configured such that the FDS 10 signals the beginning of phase 3 at line 422 ( Fig. 3) and compensates for delays in data processing, signal propagation, and the physical pulse of components, as discussed above. If the first trigger condition is met, method 910 proceeds immediately and directly to step 930. In an alternative form, controller 122 may implement a time or position delay after the first trigger condition is met, as discussed above, and then proceed immediately and directly to step 930.

[0067] At step 930, the controller 122 operates the automatic tool 110 at a second setting. At the second setting, the controller 122 sends a signal to the driver 114 to immediately begin operating the driver 114 at a second speed and a second axial feed force.

[0068] While slight fluctuations may occur, the control signals from the controller 122 in the second setting are configured to operate the screwdriver at a constant speed and axial feed force during step 930.

[0069] While the screwdriver 114 is applying the second speed and the second axial feed force, the sensor(s) 118 can continue to detect the depth (i.e., position) of the FDS 10. The sensor(s) 118 can also detect torque values. The controller 122 continues to receive signals from the sensor(s) 118.

[0070] At step 934, the controller 122 determines, based on signals from the sensor(s) 118, whether a predetermined final trip condition is met. The final trip condition may be a final torque value. The controller 122 continues to operate the screwdriver 114 at the second speed and the second axial force until the final trip condition is met. Once the final trip condition is met, the controller 122 stops the rotation and axial force of the screwdriver 114 to end the method, as indicated by step 938. It should be understood that additional steps may be taken upon reaching step 938, and the statement that the specific method discussed ends is not intended to imply that the screwdriver 114 and / or the controller 122 must stop operation in any function at that point. For example, industry standard processes for torque control may be used to tighten the connection.

[0071] In another form, the apparatus and methods described herein may also be combined with the teachings of U.S. Application No. 18 / 365,660, filed August 4, 2023, the entire disclosure of which is incorporated herein by reference. For example, the screw volatility threshold of the present disclosure may be used as the first trigger condition described in U.S. Application No. 18 / 365,660, instead of the axial velocity (i.e., depth gradient) described therein.

[0072] Thus, the method and system described here compensate for variations in sensors, screw geometry, substrate geometry and other manufacturing factors, such as gaps caused by part fit in the assemblies and fixtures.

[0073] Unless expressly stated otherwise herein, all numerical values ​​indicating mechanical / thermal properties, composition percentages, dimensions and / or tolerances, or other characteristics are to be understood as modified by the word "about" or "approximately" when describing the scope of the present disclosure. This modification is desirable for various reasons, including industrial practice, material, manufacturing and assembly tolerances, and testability.

[0074] As used in this document, the phrase at least one of A, B, and C should be interpreted to mean a logical (A OR B OR C) using a non-exclusive logical OR, and should not be interpreted to mean "at least one of A, at least one of B, and at least one of C."

[0075] As used in this application, the terms "controller" and / or "module" may refer to, be part of, or include: an application specific integrated circuit (ASIC); a digital, analog, or mixed analog / digital discrete circuit; a digital, analog, or mixed analog / digital integrated circuit; a combinable logic circuit; a field programmable gate array (FPGA); a processor circuit (shared, dedicated, or group) that executes code; a memory circuit (shared, dedicated, or group) that stores code executed by the processor circuit; other suitable hardware components that provide the described functionality; or a combination of some or all of the foregoing, such as in a system-on-chip.

[0076] The term "memory" is a subset of the term "computer-readable medium." As used herein, the term "computer-readable medium" does not include transitory electrical or electromagnetic signals propagating through a medium (such as a carrier wave); therefore, the term "computer-readable medium" can be considered tangible and non-transitory.Non-limiting examples of a non-transitory, tangible computer-readable medium include non-volatile memory circuits (such as a flash memory circuit, an erasable programmable read-only memory circuit, or a mask read-only memory circuit), volatile memory circuits (such as a static random access memory circuit or a dynamic random access memory circuit), magnetic storage media (such as an analog or digital magnetic tape or a hard disk drive), and optical storage media (such as a CD, a DVD, or a Blu-ray Disc).

[0077] The devices and methods described in this application may be implemented in part or in whole by a special-purpose computer created by configuring a general-purpose computer to perform one or more specific functions embodied in computer programs. The functional blocks, flowchart components, and other elements described above serve as software specifications that can be translated into computer programs through the routine work of a skilled technician or programmer.

[0078] The description of the disclosure is purely exemplary in nature, and thus, examples that do not depart from the substance of the disclosure are intended to be within the scope of the disclosure. Such variations should not be considered a departure from the spirit and scope of the disclosure.

[0079] According to the present invention, a method for installing a flow drilling screw (FDS) into a substrate includes: engaging the FDS with an automatic tool; operating the automatic tool at a first setting to screw the FDS into the substrate by causing the substrate to flow to allow the FDS to penetrate the substrate, the first setting configured to rotate the FDS at a first speed and apply a first axial feed force to the FDS, the first setting configured to cause the substrate to flow to allow the FDS to penetrate the substrate; acquiring, via a sensor, axial position data of the FDS while operating the automatic tool; calculating.via a controller, of volatility of the axial position data of the FDS; and switching, via the controller, the automatic tool from the first setting to a second setting in response to the controller determining that a trigger condition has occurred, wherein the trigger condition includes one of the following: a value of the volatility exceeding a predetermined volatility value; and the value of the volatility being within a predetermined range of a maximum volatility value; wherein the second setting is configured to rotate the FDS at a second speed and apply a second axial feed force to the FDS, wherein the second speed is less than the first speed.

[0080] In one aspect of the invention, the triggering condition includes the value of the volatility exceeding the predetermined volatility value, wherein the predetermined volatility value is greater than or equal to 0.5 mm.

[0081] In one aspect of the invention, the trigger condition includes the volatility value being within a predetermined range of a maximum volatility value.

[0082] In one aspect of the invention, in response to the maximum volatility value being reached, the controller switches the automatic tool from the first setting to the second setting.

[0083] In one aspect of the invention, the method includes calculating a predicted maximum volatility value, wherein the controller switches the automatic tool from the first setting to the second setting based on the predicted maximum volatility value.

[0084] In one aspect of the invention, the value is an average of the volatility over a subset of time. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US 18 / 466 775

[0044] US 18 / 365 660

[0071]

Claims

[1] A method of installing a flow-drilling screw (FDS) in a substrate, the method comprising: Engaging the FDS with an automatic tool; Operating the automatic tool at a first setting to screw the FDS into the substrate by causing the substrate to flow to allow the FDS to penetrate the substrate, the first setting being configured to rotate the FDS at a first speed and apply a first axial feed force to the FDS, the first setting being configured to cause the substrate to flow to allow the FDS to penetrate the substrate; Acquiring axial position data of the FDS via a sensor while the automatic tool is operating; Calculating a volatility of the axial position data of the FDS via a controller; and Switching the automatic tool from the first setting to a second setting in response to the volatility, the second setting configured to rotate the FDS at a second speed and apply a second axial feed force to the FDS, the second speed being less than the first speed. [2] The method of claim 1, wherein the controller switches the automatic tool from the first setting to the second setting in response to the controller determining that a trigger condition has occurred, the trigger condition including at least one of the following: a volatility value exceeds a predetermined volatility value; and the volatility value lies within a predetermined range of a maximum volatility value. [3] The method of claim 2, wherein the predetermined volatility value is greater than or equal to 0.5 mm. [4] The method of claim 2, wherein the controller is configured to wait for a predetermined delay time after the controller determines that the trigger condition has occurred and before switching the automatic tool from the first setting to the second setting. [5] The method of claim 2, wherein the value is an average of the volatility over a subset of time. [6] The method of claim 1, wherein the controller switches the automatic tool from the first setting to the second setting in response to a maximum volatility value being reached. [7] The method of claim 1, further comprising calculating a predicted maximum volatility value, wherein the controller switches the automatic tool from the first setting to the second setting based on the predicted maximum volatility value. [8] The method of claim 7, wherein the controller switches the automatic tool from the first setting to the second setting based on the predicted maximum volatility value, but before the maximum volatility value is reached. [9] The method of any one of claims 1 to 8, wherein the controller calculates the volatility using at least one of a true range (TR) formula and a standard deviation formula. [10] System for installing a flow drilling screw (FDS), comprising: a drive unit configured to rotate the FDS at a speed about an axis while applying an axial feed force to the FDS to screw the FDS through at least one substrate; at least one sensor configured to acquire axial position data of the FDS; and a controller in communication with at least one sensor, the controller configured to determine the volatility of the axial position data of the FDS and to change the speed and the axial feed force in response to a trigger condition being reached; wherein the trigger condition includes at least one of the following: a volatility value exceeds a predetermined volatility value; and the volatility value lies within a predetermined range of a maximum volatility value. [11] The system of claim 10, wherein the trigger condition includes the value of the volatility exceeding the predetermined volatility value, wherein the predetermined volatility value is greater than or equal to 0.5 mm. [12] The system of claim 10, wherein the trigger condition includes the volatility value being within a predetermined range of a maximum volatility value. [13] The system of claim 10, wherein the value is an average of the volatility over a subset of time. [14] The method of claim 10, wherein the controller is configured to wait for a predetermined delay time after the controller determines that the trigger condition has occurred and before changing the rotational speed and the axial feed force. [15] The system of any of claims 10 to 14, wherein the controller is configured to determine the volatility using at least one of a true range (TR) formula and a standard deviation formula.

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