CN116893023A - Method for operating an impact screwdriver, control device for carrying out said method, and impact screwdriver - Google Patents
Method for operating an impact screwdriver, control device for carrying out said method, and impact screwdriver Download PDFInfo
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Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L3/00—Measuring torque, work, mechanical power, or mechanical efficiency, in general
- G01L3/02—Rotary-transmission dynamometers
- G01L3/04—Rotary-transmission dynamometers wherein the torque-transmitting element comprises a torsionally-flexible shaft
- G01L3/10—Rotary-transmission dynamometers wherein the torque-transmitting element comprises a torsionally-flexible shaft involving electric or magnetic means for indicating
- G01L3/101—Rotary-transmission dynamometers wherein the torque-transmitting element comprises a torsionally-flexible shaft involving electric or magnetic means for indicating involving magnetic or electromagnetic means
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06N—COMPUTING ARRANGEMENTS BASED ON SPECIFIC COMPUTATIONAL MODELS
- G06N20/00—Machine learning
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25B—TOOLS OR BENCH DEVICES NOT OTHERWISE PROVIDED FOR, FOR FASTENING, CONNECTING, DISENGAGING OR HOLDING
- B25B21/00—Portable power-driven screw or nut setting or loosening tools; Attachments for drilling apparatus serving the same purpose
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25B—TOOLS OR BENCH DEVICES NOT OTHERWISE PROVIDED FOR, FOR FASTENING, CONNECTING, DISENGAGING OR HOLDING
- B25B23/00—Details of, or accessories for, spanners, wrenches, screwdrivers
- B25B23/14—Arrangement of torque limiters or torque indicators in wrenches or screwdrivers
- B25B23/147—Arrangement of torque limiters or torque indicators in wrenches or screwdrivers specially adapted for electrically operated wrenches or screwdrivers
- B25B23/1475—Arrangement of torque limiters or torque indicators in wrenches or screwdrivers specially adapted for electrically operated wrenches or screwdrivers for impact wrenches or screwdrivers
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L3/00—Measuring torque, work, mechanical power, or mechanical efficiency, in general
- G01L3/02—Rotary-transmission dynamometers
- G01L3/04—Rotary-transmission dynamometers wherein the torque-transmitting element comprises a torsionally-flexible shaft
- G01L3/10—Rotary-transmission dynamometers wherein the torque-transmitting element comprises a torsionally-flexible shaft involving electric or magnetic means for indicating
- G01L3/101—Rotary-transmission dynamometers wherein the torque-transmitting element comprises a torsionally-flexible shaft involving electric or magnetic means for indicating involving magnetic or electromagnetic means
- G01L3/102—Rotary-transmission dynamometers wherein the torque-transmitting element comprises a torsionally-flexible shaft involving electric or magnetic means for indicating involving magnetic or electromagnetic means involving magnetostrictive means
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
- G01L5/24—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for determining value of torque or twisting moment for tightening a nut or other member which is similarly stressed
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- Details Of Spanners, Wrenches, And Screw Drivers And Accessories (AREA)
Abstract
Method for operating an impact screwdriver, control device for carrying out said method, and impact screwdriver. In a method (18) for operating an impact driver (1), a time sequence of sensor signals (20) of a torque sensor (5) of the impact driver (1) is received during operation of the impact driver (1). -determining the number of pulses (24) of the sensor signal (20) and determining at least one signal variable (25, 26, 27, 28) of the sensor signal (20) on the basis of the time sequence. The torque is determined on the basis of the number of pulses (24) and the at least one signal variable (25, 26, 27, 28).
Description
Technical Field
The invention relates to a method for operating an impact screwdriver, to a control device for carrying out the method, and to an impact screwdriver.
Background
In many applications it is necessary to measure the torque of a rotating component. For example, in an electrical device with an electric motor, the torque can be measured in order to determine and display the work progress and to be able to take appropriate measures based on the work progress. It is known from the prior art to measure the torque, for example by means of a preloaded torque sensor, a torque sensor based on surface acoustic waves, a torque sensor based on piezo-electric response, an optical torque sensor, an inductive torque sensor or a torque sensor based on the magnetoelastic effect. Different methods for torque measurement are known, wherein the magnetoelastic effect is utilized. In the so-called verari effect (reverse magnetostriction), the applied torque load causes a change in magnetization.
The electric impact screwdriver works normally according to the principle of tightening bolts or screws by means of a wrench, wherein impacts are applied to the wrench with a hammer, so that torque is formed at the time of tightening impact by impact. The advantage of impact screwdrivers is that they can have very high power relative to their weight and their size. The reaction force transmitted back to the operator is also very small. This allows a flexible and simple operation of the impact screwdriver.
The nuts and screws must be tightened with the proper torque, but not so tight as to cause damage to the components, and not so loose that the assembly does not loosen or spread out. Since screws are manufactured with a defined strength level, common design criteria are: the screw is preloaded to a percentage of this strength of the screw (sometimes referred to as the "test load"). The torque used to achieve this load under typical conditions is determined for different screw sizes and screw masses and is known for the most important and common connecting elements. Such torque, commonly referred to as applied torque, is the final torque resistance that the hand-held screwdriver or power screwdriver has when tightening the fastener element at a continuous speed.
In general, the tightening torque specification is made assuming such continuous torque application. Many hand-held screwdrivers and electric screwdrivers with continuous motion control the applied torque in such a way that they measure the torque of the tool during tightening and stop when a given value is reached. The stopping may be effected mechanically, for example by means of a clutch or electronically in case a converter is used, in order to signal the tool motor to stop.
Direct measurement of torque at impact tightening is difficult to correlate with continuously applied torque. The difficulty in establishing such a relationship is why a small number of impact drivers using torque measurements are commercially available. The measurement of torque is typically used for control only. It is thereby possible, for example, for the screw or nut to be screwed too tightly or too loosely.
Disclosure of Invention
The object of the present invention is to specify an improved method for operating an impact driver, which enables a real-time measurement of the tightening torque and a correlation between the real-time impact torque and the tightening torque. The impact driver is thereby able to be controlled in dependence on the measured and required torque. Another object is to provide an improved control device for carrying out the method and an improved impact screwdriver. These objects are achieved by a method for operating an impact screwdriver, a control device for carrying out the method, and an impact screwdriver having the features of the invention. In a preferred embodiment, an advantageous embodiment is described.
A method for operating an impact driver has the following method steps. In the operation of the impact driver, a time sequence of sensor signals of a torque sensor of the impact driver is received. The number of pulses of the sensor signal is determined based on the time sequence and at least one signal variable of the sensor signal is determined. The torque is determined based on the number of pulses and the at least one signal variable.
The impact driver has an electric motor for driving a rotary part of the impact driver, a pulse device for generating a pulse-like torque, a torque sensor for measuring the torque of the rotary part, and a control device. The control device is configured for performing the method.
The pulses of the sensor signal represent the impacts applied by the impact driver in operation. As the at least one signal variable, in one embodiment, an average value and/or a median value and/or a maximum value and/or a minimum value of the sensor signal are determined. In one embodiment, the torque sensor has a magnetic field sensor. The magnetic field sensor is configured for measuring a magnetic field of a component that is magnetic and fastened to the rotating component based on a magnetoelastic effect.
Advantageously, the method enables a correlation to be derived between the measured variable and the torque, wherein in this embodiment of the torque sensor with a magnetic field sensor the measured variable is the magnetic field strength. In this way, the torque acting on the rotary part of the impact driver can be determined during the working process. In this way, for example, a desired tightening torque can be avoided, for example, when screwing down a screw, being exceeded or undershot. In this way, the components to be assembled can be protected from mechanical damage. The real-time torque value is determined for each impact or pulse of the impact driver. Thus, feedback on the progress of work can be immediately displayed to the user. Thus, the necessity of rechecking the completed work can be eliminated by using an external sensor. In order to represent each impact of the impact driver in the time series, the bit rate at which the time series is recorded must be selected to be sufficiently high.
In one embodiment, the number of pulses is weighted with a weighting index. The torque is determined based on the number of weighted pulses. In one embodiment, the at least one signal parameter of the sensor signal is weighted with a weighting factor. The torque is determined based on the at least one weighted signal variable. Advantageously, experimental results concerning the relationship between torque and the number of pulses and the at least one signal variable are thus taken into account in determining the torque. The number of pulses here contributes to the torque in a polynomial manner, while the signal quantity contributes linearly to the torque. The torque can thus be determined particularly precisely.
In one embodiment, the number of pulses, the at least one signal variable and the torque are each determined locally for a group of data points that follow one another with a predefinable number of data points and are updated globally for the time series after each group of data points of the time series. Advantageously, the previously taken torque and the updated torque can be combined with each other in order to predict when the tightening torque will be reached. This achieves that the torque of the impact driver is adapted during the working process, so that the tightening torque is not exceeded, for example, during a further impact.
In one embodiment, the at least one weighting factor and/or the weighting index is found by iteratively matching the at least one weighting factor and/or the weighting index and minimizing the loss function based on a loss function that depends on the torque of the set of data points and the final torque value of the set of data points. The torque is determined based on the determined weighting factors and/or weighting indices.
Advantageously, the real-time tightening torque is derived from the measured value of the magnetoelastic torque sensor using machine learning, so that the torque can be determined particularly quickly and reliably.
In one embodiment, the impact driver is actuated based on the determined torque. In one embodiment, the impact driver is actuated in a closed control loop. Advantageously, measures can thereby be taken to prevent over-tightening.
The control device for performing the method according to one of the embodiments is configured for: a time sequence of sensor signals of a torque sensor of an impact driver is received during operation of the impact driver, a number of pulses of the sensor signals and at least one signal variable of the sensor signals are determined based on the time sequence, and a torque is determined based on the number of pulses and the at least one signal variable.
Drawings
Fig. 1 schematically shows the components of an impact driver 1;
fig. 2 schematically shows further components of the impact driver 1 of fig. 1;
fig. 3 shows schematically the components of the control device 10 and serves to illustrate a first basic principle of the method for operating the impact driver 1;
fig. 4 shows a method 18 for operating the impact driver 1;
fig. 5 shows a graph in which the torque 29 is plotted against the number of impact pulses 24;
fig. 6 shows an alternative, within the scope of which an algorithm based on a machine learning method is used in order to determine the weighting factors w 1 、w 2 、w 3 And w 4 Weighting index w 5 。
Detailed Description
Fig. 1 schematically shows the components of an impact driver 1.
The impact driver 1 can also be configured as a rotary impact driver. The impact driver 1 is provided, for example, for tightening a screw or a nut. For this purpose, the impact driver 1 has a drill chuck (Bohrfutter). The drill chuck is arranged for receiving a driver bit (schraubbbits) and is connectable with a rotary part 2 of the impact driver 1. In the operation of the impact driver 1, torque is applied to the rotary member 2. In order to drive the rotary part 2, the impact driver 1 has an electric motor 3. In order to generate a pulsed torque, the impact driver 1 has a pulse device 4. The pulse device 4 of the impact driver 1 is known from the prior art. For example, the impulse device 4 can be operated hydraulically. However, the pulse device 4 is not explained in more detail in the context of the present description.
In order to measure the torque exerted on the rotary part 2, the impact driver 1 has a torque sensor 5. The torque sensor 5 is illustratively based on the inverse magnetostriction effect. In this case, the torque load applied to the rotary member 2 may cause a change in magnetization of the magnetic member 6 of the torque sensor 5 fastened to the rotary member 2. However, the torque sensor 5 can also be based on other effects. The torque sensor 5 can also be configured as the torque sensor mentioned in the introduction of the present specification.
As magnetic component 6, the torque sensor has an amorphous and metallic glass ribbon, which is fastened to rotary component 2. The glass ribbon can have, for example, fe 78 B 13 Si 9 Or another amorphous metallic material, for example. The initially amorphous glass ribbon of the torque sensor 5 has been heat treated to induce a nanocrystalline structure in the glass ribbon. "nanocrystalline structure" shall mean a polycrystalline structure having an average grain size in the submicron range. The nanocrystalline structure induced by the heat treatment provides this advantage: the glass ribbon has a high magnetostriction coefficient or magnetoelastic coefficient so that the inverse magnetostriction can be utilized efficiently. For example, the heat treatment of the glass ribbon can be performed at a temperature between the curie temperature and the crystallization temperature or, for example, within the range of crystallization temperatures of the glass ribbon.
In addition, the glass ribbon of the torque sensor has been magnetized, for example in an external magnetic field of 0.3T. In the case of magnetization parallel to the axis of rotation of the rotating part 2, it is for example possible to: the magnetic field generated by the magnetization of the ribbon is uniformly distributed along the ribbon having a strength of, for example, greater than 10G. In the case of magnetization perpendicular to the axis of rotation 2, it is possible to: the magnetization changes locally.
The magnetized glass ribbon and the rotating member 2 form a transducer device 7 (english: transducer) of the torque sensor 5. The heat-treated and magnetized glass ribbon is shaped, for example cylindrically, and is fitted onto the rotating part 2. For fastening the glass ribbon on the rotating member 2, an adhesive, for example, can be used.
The impact driver 1 also has a cover 8. A cover 8 is disposed over the glass ribbon. The glass ribbon concentrically surrounds the rotating member 2. The cover 8 concentrically surrounds the glass ribbon. For detecting the magnetic field of the glass ribbon, the cover 8 has a magnetic field sensor 9. The torque sensor 5 is formed of a magnetic member 6 and a magnetic field sensor 9. As the cover 8, a circuit board can be formed, for example, with an integrated magnetic field sensor 9. The magnetic field sensor 9 is disposed spaced apart from the glass ribbon. Thereby, it is possible to measure the torque applied to the rotary part 2 in the operation of the impact driver 1 without contact. The torque sensor 5 can also have at least one further magnetic field sensor 9. Thus, the sensor signal can be subjected to differential analysis processing.
The magnetic field sensor 9 can be based on different phenomena such as hall effect or magneto-resistance, e.g. anisotropic magneto-resistance (english: anisotropic magnetoresistance, AMR), giant magneto-resistance (english: giant magnetoresistance, GMR) or einem tunnel resistance (english: tunnel magnetoresistance, TMR). GMR sensors offer such advantages: which can be disposed without making mechanical contact with the glass ribbon.
The components required for the operation of the torque sensor 5 also include a battery or other (temporary) power source (this is not shown in fig. 1) and a control device 10 for addressing and reading the magnetic field sensor 9 and the circuit board. Furthermore, communication means, not represented in fig. 1, can be integrated into the cover 8 in order to display or wirelessly transmit the measured data.
The rotational movement of the rotating member 2 causes a mechanical loading of the glass ribbon. This results in a change in the magnetic field emitted by the ribbon due to the reverse magnetostriction effect. The magnetic field strength of the magnetic field of the glass ribbon can be measured by means of the magnetic field sensor 9. By varying the torque applied to the rotating part 2 and by measuring the magnetic field strength of the magnetic field of the glass ribbon, the torque sensor 5 can be calibrated, wherein, for example, a linear relationship between the magnetic field strength and the torque can be obtained, which enables an estimation of the applied torque in the operation of the impact driver.
Figure 2 schematically shows further components of the impact driver 1 of figure 1,
the impact driver 1 has a preprocessing device 11 for preprocessing the sensor signal of the torque sensor 5. In the exemplary embodiment of the impact driver 1 with a torque sensor 5 based on the magnetoelastic effect, the sensor signal is the signal of a magnetic field sensor 9, which is indicative of the change in the magnetic field strength of the magnetic component 6 or the magnetic field of the glass ribbon due to the torque load acting on the glass ribbon. The preprocessing device 11 can be configured, for example, for filtering the sensor signals. However, the preprocessing device 11 can also be omitted. In order to digitize the sensor signal or the preprocessed sensor signal, the impact driver 1 has an analog/digital converter 12.
The control device 10 of the impact driver 1 is designed to receive and evaluate the digitized sensor signals. The impact driver 1 has a memory 13 connected to the control device 10, in which memory the signal values can be stored. In addition to the control device 10, the impact driver 1 additionally has an upper control 14. The upper control 14 is configured for operating and controlling the impact driver 1.
As already mentioned in the introduction of the present description, it is difficult to correlate the measurement of the torque at the time of impact tightening with the torque continuously applied to the rotary part 2 of the impact driver 1. The control device 10 of the impact driver 1 is designed to carry out a method for operating the impact driver 1 that overcomes this problem.
Fig. 3 shows schematically the components of the control device 10 and serves to illustrate a first basic principle of the method for operating the impact driver 1.
The control device 10 is configured to receive digitized sensor signals from the analog/digital converter 12. The control device 10 is connected to a memory 13. On the memory 13, a total of five data points 15 of the time series of sensor signals can be saved in a buffered form, for example. However, more or fewer data point 15 values can also be saved in memory. The control device 10 has a detection device 16. The detection means 16 are arranged for checking: whether the impact driver 1 is in impact operation. The detection device 16 can be configured, for example, for determining the impact operation of the impact driver 1 by: the detection device 16 takes the time derivative of the sensor signal and checks: whether the differentiated sensor signal exceeds a predefinable threshold value. If this is the case, the analysis processing device 17 of the control device 10 obtains the torque of the rotating member 2 based on the sensor signal.
The detection device 16 is designed to check whether the impact driver 1 is in impact operation at predefinable time intervals until impact operation is determined. The evaluation device 17 is therefore designed to determine the torque only when the impact driver 1 is in impact operation. However, this is not mandatory. The evaluation device 17 can also be configured to always determine the torque. In this case too, the detection device 16 can be dispensed with. The evaluation device 17 is configured to supply the determined torque to the upper control unit 14.
Fig. 4 shows a method 18 for operating the impact driver 1.
In a first method step 19, a time sequence of sensor signals 20 is received by the control device 10. Fig. 4 schematically shows an exemplary sensor signal 20 of the magnetic field sensor 9. Here, the magnetic field strength 21 is plotted against the time 22.
After the time series of the sensor signals 20 of the torque sensor 5 or of the magnetic field sensor 9 has been received and optionally after the impact operation has been determined, in a second method step 23 the number of pulses 24 of the sensor signals 20 is determined on the basis of the time series. The pulse 24 of the sensor signal 20 represents the impact during operation of the impact driver 1. The impulse can then be detected, for example, in the sensor signal 20 if the sensor signal 20 has a local maximum with a predefinable half-value width.
In addition to the number of pulses 24 of the sensor signal 20, at least one signal variable 25, 26, 27, 28 is determined on the basis of the time sequence. The at least one signal variable can be, for example, an average 25 of the sensor signal 20 and/or a median 26 of the sensor signal 20 and/or a maximum 27 of the sensor signal 20 and/or a minimum 28 of the sensor signal 20.
Experiments have shown that the torque acting on the rotating part depends on the number of impact pulses when tightening the screw or nut. Fig. 5 shows a graph in which the torque 29 is plotted against the number of impact pulses 24. Thus, in the operation of the impact driver 1, the subsequent torque is dependent on the number of impact pulses 24 that have already been carried out. Referring to fig. 4, for this reason, the torque of the impact driver 1 is determined in a third method step 30 on the basis of the number of pulses 24 and the at least one signal variable 25, 26, 27, 28.
Furthermore, experiments have shown that the dependence of the torque 29 on the number of impact pulses 24 can be described by a polynomial dependence. Conversely, the signal variables 25, 26, 27, 28 mentioned contribute in a linear manner to the torque 29. For this reason, however, it is desirable, but not mandatory, to weight the number of pulses 24 with a weighting index and/or the at least one signal parameter 25, 26, 27, 28 of the sensor signal 20 with a weighting factor. It is proposed to find the torque T as follows:
here the number of the elements to be processed is,<B>is the average value of the sensor signal,is the median value of the sensor signal, +.>Is the maximum value of the sensor signal and +.>Is the minimum of the sensor signal. Since the torque sensor comprises a magnetic field sensor in the present example, the signal variable is always dependent on the magnetic field B of the magnetic component 6 or the glass ribbon. w (w) 1 、w 2 、w 3 And w 4 Is a weighting factor for the corresponding signal parameter. w (w) 5 Is a weighted index of the number N of pulses. As already mentioned, it may be sufficient to determine the torque T using only one signal variable 25, 26, 27, 28. Alternatively, the weighting factor w 1 、w 2 、w 3 And w 4 Can be used forIs chosen to be very small so as to take into account little or substantially no corresponding signal parameter 25, 26, 27, 28.
As already stated, the values of the sensor signal 20 can be stored in a buffered form in the memory 13. In the exemplary illustration of fig. 3, it is shown that a total of five values of data points 15 can be saved. For this reason, it can be expedient to determine the number of pulses 24 of the sensor signal 20 and the at least one signal variable 25, 26, 27, 28 for the set of data points 15 of the time series. For example, if the values of the five data points 15 of the time series can be stored in the memory 13, the number of pulses 24 of the sensor signal 20 and the at least one signal variable 25, 26, 27, 28 for each group of the five data points 15 are determined.
In the method, the number N of pulses and the at least one signal variable 25, 26, 27, 28 and the torque T can be determined locally for each group of consecutive data points 15 having a predefinable number of data points 15. The number N of pulses and the at least one signal parameter 25, 26, 27, 28 can be updated globally (i.e. for the entire time series) after each data point 15 of the time series.
Weighting factor w 1 、w 2 、w 3 And w 4 Weighting index w 5 Can be predefined and can be determined, for example, by nonlinear regression analysis. Fig. 6 shows an alternative, within the scope of which an algorithm based on a machine learning method is used in order to determine the weighting factors w 1 、w 2 、w 3 And w 4 Weighting index w 5 。
First, for the weighting factor w 1 、w 2 、w 3 And w 4 Weighting index w 5 Selecting a random value w i1 、w i2 、w i3 、w i4 、w i5 . For each group 1 to P of data points 15 of the time series, the number N of pulses is determined p . Likewise, for each group 1 to P of data points 15 of the time series, at least one signal variable is determined<B p >、In the example presented, all the exemplary mentioned signal parameters for each group of data points 15 are found<B p >、/>
In the next step, the torque T for each group of data points 15 is determined according to relation (1) p . Based on the torque T calculated p And based on the final torque value T of groups 1 to P of data points 15 p ' find the loss function g (q), where q represents the weight w i1 、w i2 、w i3 、w i4 、w i5 . The final torque value T p ' is the torque value of the last data point in time in the groups 1 to P of data points, respectively. The loss function g is illustratively chosen as follows: by applying a torque T to the target p And final torque value T p ' sum of squares of deviations normalized to the number of groups P between (so-called Gaussian losses), where T p ＝f p T w applies and is an alternative representation of relation (1). Here, the summation is performed over all groups 1 to P. w is a weighting factor w included as a component 1 、w 2 、w 3 And w 4 Is a vector of (a). f (f) p T Is a transposed vector whose components are respectively represented by the product B j *N w5 Formed, wherein B is j Representing signal parameters<B p >、However, the loss function g can also be defined differently, for example the loss function can be based on the Laplace loss (Laplace-verlost). In this case, consider the torque T calculated p And final torque value T p The simple difference between' rather than their square.
The loss function g is based on the torque T p And final torque value T of groups 1 to P p ' to be found. Then, with minimumModifying the weight w in a manner that normalizes the loss function i1 、w i2 、w i3 、w i4 、w i5 . The modified weights are used to re-determine the torque T for each group 1 to P according to relation (1) p . Again, the loss function g can be calculated based on the re-calculated torque and the final torque value and minimized again by re-modifying the weights. Therefore, the sum weight w of the loss function g is calculated i1 、w i2 、w i3 、w i4 、w i5 The modification of (c) is performed in an iterative manner until the loss function cannot be further minimized. Thereby obtaining an optimized weight w 1 、w 2 、w 3 、w 4 、w 5 . The optimized weights w are then 1 、w 2 、w 3 、w 4 、w 5 For obtaining the current torque T by the relation (1) of the rotating member 2. In this case, updated signal variables are used<B p >、
This torque T represents the real-time torque of the rotating member 2. The impact driver 1 can be actuated on the basis of the determined real-time torque. For this purpose, the determined torque T is transmitted to the upper control unit 14. The upper control unit 14 is designed to take in measures based on the determined torque T. For example, the upper control 14 can be configured to increase or decrease the torque depending on the achieved work schedule and to switch off the impact driver 1 when a certain work schedule is reached. If, for example, the tightening torque required for tightening the screw is not reached, it is possible to torque to reach this tightening torque. If this tightening torque is reached, the upper control unit 14 is designed to terminate the working process by switching off the impact driver 1. If the tightening torque is exceeded, the operation can also be ended by the upper control 14. Thereby, overload and damage of the screw and the nut can be prevented. The method makes it possible in particular to operate the impact driver 1 in a closed control loop. In this way, a particularly precise tightening torque can be achieved without exceeding the tightening torque.
Claims (11)
1. A method (18) for operating an impact driver (1), having the following method steps (19, 23, 30):
receiving a time sequence of sensor signals (20) of a torque sensor (5) of the impact driver (1) during operation of the impact driver (1),
-determining the number of pulses (24) of the sensor signal (20) and at least one signal variable (25, 26, 27, 28) of the sensor signal (20) on the basis of the time sequence,
-determining a torque (29) based on the number of pulses (24) and the at least one signal parameter (25, 26, 27, 28).
2. The method (18) according to claim 1,
wherein the number of pulses (24) is weighted by a weighting index,
wherein the torque (29) is determined based on the weighted number of pulses.
3. The method (18) according to claim 1 or 2,
wherein the at least one signal parameter (25, 26, 27, 28) of the sensor signal (20) is weighted with a weighting factor,
wherein the torque (29) is determined on the basis of at least one weighted signal variable.
4. The method (18) according to any one of the preceding claims,
wherein an average value (25) and/or a median value (26) and/or a maximum value (27) and/or a minimum value (28) of the sensor signal (20) are determined as the at least one signal variable (25, 26, 27, 28).
5. The method (18) according to any one of the preceding claims,
wherein the number of pulses (24), the at least one signal variable (25, 26, 27, 28) and the torque (29) are determined in each case locally for a group of data points (15) which are consecutive to one another and have a predefinable number of data points (15), and the number of pulses (24), the at least one signal variable (25, 26, 27, 28) and the torque (29) are updated globally for the time series after each group of data points (15) of the time series.
6. A method (18) according to claim 5 and any one of claims 2, 3,
wherein the at least one weighting factor and/or the weighting index is/are determined by iteratively matching the at least one weighting factor and/or the weighting index and minimizing the loss function based on a loss function depending on a local torque (29) of the set of data points (15) and a final torque value of the set of data points (15),
wherein the global torque (29) is determined on the basis of the determined weighting factors and/or weighting indices.
7. The method (18) according to any one of the preceding claims,
wherein the impact driver (1) is actuated on the basis of the determined torque (29).
8. The method (18) according to claim 7,
wherein the impact driver (1) is actuated in a closed control loop.
9. A control device (10) for performing a method (18) according to any one of the preceding claims,
wherein the control device (10) is designed to receive a time sequence of sensor signals (10) of a torque sensor (5) of the impact driver (1) during operation of the impact driver (1),
wherein the control device (10) is designed to determine, based on the time sequence, the number of pulses (24) of the sensor signal (20) and at least one signal variable (25, 26, 27, 28) of the sensor signal (20),
wherein the control device (10) is designed to determine the torque (29) on the basis of the number of pulses (24) and the at least one signal variable (25, 26, 27, 28).
10. An impact driver (1) is provided with: an electric motor (3), a pulse device (4), a torque sensor (5) and a control device (10) according to claim 9, the electric motor (3) being used for driving a rotary part (2) of the impact driver (1), the pulse device (4) being used for generating a pulse-like torque (29), the torque sensor (5) being used for measuring the torque (29) of the rotary part (2).
11. The impact driver (1) according to claim 10,
wherein the torque sensor (5) has a magnetic field sensor (9),
wherein the magnetic field sensor (9) is designed to measure the magnetic field of a magnetic component (6) fastened to the rotating component (2) on the basis of the magnetoelastic effect.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE102022203501.1A DE102022203501A1 (en) | 2022-04-07 | 2022-04-07 | Method for operating an impact wrench, control device for carrying out the method and impact wrench |
| DE102022203501.1 | 2022-04-07 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116893023A true CN116893023A (en) | 2023-10-17 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310364984.0A Pending CN116893023A (en) | 2022-04-07 | 2023-04-07 | Method for operating an impact screwdriver, control device for carrying out said method, and impact screwdriver |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN116893023A (en) |
| DE (1) | DE102022203501A1 (en) |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| ZA762927B (en) | 1975-05-19 | 1977-04-27 | Standard Pressed Steel Co | Impact wrench with joint control |
| DE4336465A1 (en) | 1993-10-26 | 1995-04-27 | Bosch Gmbh Robert | Impact or pulse screwing |
| DE19845871A1 (en) | 1997-10-08 | 1999-04-15 | Christoph Prof Dr Ing Hartung | Tightening screws in bone structures |
| EP1136188B1 (en) | 2000-03-16 | 2007-05-16 | Makita Corporation | Power impact tools with impact sound detecting means |
| DE102005015900B4 (en) | 2004-04-10 | 2020-07-09 | Marquardt Gmbh | Power tools, in particular impact wrenches |
| TWI498196B (en) | 2012-10-05 | 2015-09-01 | China Pneumatic Corp | A method of indirectly coupled torque control and the mechanism thereof |
-
2022
- 2022-04-07 DE DE102022203501.1A patent/DE102022203501A1/en active Pending
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2023
- 2023-04-07 CN CN202310364984.0A patent/CN116893023A/en active Pending
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|---|---|
| DE102022203501A1 (en) | 2023-10-12 |
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