Resonance method of vibration system, converter, excitation unit and vibration system

Abstract

The invention relates to a resonance method (1) for a vibration system (2) for resonating an excitation unit (4) having a vibration mass (3), the method comprising the following steps: deflection detection (5) of a deflection (x) of the vibration mass (3); velocity construction (6) of the velocity (v) of the vibration mass (3) by differentiating the deflection (x); mechanical phase (θ) determination by means of the deflection (x) and the velocity (v); m ) phase generation (7); with the help of the correction value (k θ ) performs phase correction (8) on the mechanical phase (θm) to form a corrected phase (θ k ); by means of at least one P adjustment based on the corrected phase (θ k ) to construct (9) electrical angular frequency (ω el ); Based on the electrical angular frequency (ω el ) to generate (10) electrical phase (θ el ); Based on the electric phase (θ el ) to construct the correction factor (k F ); and using the correction factor (k F ) applies a set value (12) to an excitation set value (13) to generate a corrected excitation set value (14). The invention also relates to a converter (20), an excitation unit (4) having the converter (20), and a vibration system (2) having the excitation unit (4) and a vibration mass (3).

Description

Technical Field

[0001] The invention relates to a resonance method for a vibration system for resonating an excitation unit having a vibration mass. The invention also relates to a converter, an excitation unit and a vibration system. Background Art

[0002] Industrial applications with an electromechanical excitation unit for generating oscillations of a vibrating mass, in which a vibrating system (hereinafter referred to as vibration system) is to be excited by the vibrating mass in a resonant frequency range, often require the determination or estimation of the generation of this resonant frequency or the resonant state of the excitation unit and the vibrating mass to be oscillated, in order to be able to control or regulate the operating behavior of the vibration system in an energy-efficient, reliable and cost-effective manner.

[0003] In this case, the excitation unit usually comprises an electromagnet which can be operated via an electrical converter and which causes the vibrating mass to oscillate based on inductive energy transfer.

[0004] Even slight deviations in the resonance of the excitation unit and the vibrating mass can lead to significant losses in energy efficiency / efficiency or in the quality of the required operating behavior / reliability of the respective application.

[0005] Therefore, the measurement of the resonant frequencies or the resonant states of the self-oscillations of the excitation units and vibrating masses in the corresponding machines and systems, which has hitherto been carried out separately from the actual operation, often leads to extensive downtimes in production applications, which essentially requires additional effort for the corresponding production process and thus results in considerable costs.

[0006] Such vibration systems are used, for example, as friction welding machines or vibrating conveyors.

[0007] The basic process of this type of vibration system can be briefly outlined using the example of a friction welding machine. To weld a first workpiece to a second workpiece, a vibration mass having a first workpiece carrier and the first workpiece attached thereto is forced to vibrate using an excitation unit. The vibration mass is typically mounted so that it can oscillate via a spring mechanism.

[0008] In order to generate frictional heat for the production process, a first workpiece is rubbed against a second workpiece until it welds, the second workpiece being attached to a second, usually stationary, workpiece carrier.

[0009] If the excitation takes place at a resonant frequency, ie, in a vibration resonance between the excitation unit and the vibrating mass, the desired vibrations can be generated with particularly low energy expenditure.

[0010] This resonance frequency of the vibration system is decisively determined by the vibration mass, which here comprises the first workpiece, and the spring rate of its vibratory support, ie, the spring arrangement used.

[0011] Since the first workpiece contributes to the vibrating mass, after a workpiece change of the first tool, in particular if the mass of the first workpiece changes, the resonant frequency, ie the resonant state of the excitation unit and the vibrating mass, must necessarily be re-determined at considerable expense.

[0012] Otherwise, the vibration system does not work optimally, especially in terms of energy, which means that its efficiency may be significantly reduced or lost or perhaps the required vibration amplitude cannot be achieved and the required weld quality is often insufficient.

[0013] Previous applications, such as friction welding, mainly used pre-operation methods to determine / estimate the resonant frequency so that the excitation unit could be used to excite the vibration block to achieve the desired resonant oscillation state of the excitation unit and the vibration block.

[0014] The sought resonant frequency is determined by an independent start-up test before the actual production process and is then used for operation until a new start-up attempt is required due to the use of a new first workpiece or unwanted deviations in the production process.

[0015] This means that the vibration is excited here only at the frequency determined in the start-up test, which corresponds to the desired resonant frequency of the resonant state of the excitation unit and the vibration mass during actual production, which changes due to wear, temperature differences, material removal, etc. and also during operation in the production process and is often insufficient. Summary of the Invention

[0016] The object of the present invention is therefore to provide a resonance method, a converter, an excitation unit and a vibration system which continuously determine the resonance state required for the excitation unit to resonate with the vibration mass of the vibration system during production operation and use it to operate the vibration system.

[0017] This object is achieved by a resonance method having the features provided in the invention, by a converter according to the features provided in the invention, by an excitation unit of a converter having the features provided in the invention, and by a vibration system having an excitation unit having the features provided in the invention.

[0018] To achieve the above-mentioned object, a resonance method for a vibration system is proposed, for making an excitation unit having a vibration block resonate, comprising the following steps: offset detection of an offset of the vibration block, velocity construction of a velocity of the vibration block by differentiating the offset, phase generation of a mechanical phase by the offset and the velocity, phase correction of the mechanical phase by a correction value to form a corrected phase, frequency construction of an electrical angular frequency based on the corrected phase by at least one P adjustment, phase generation of an electrical phase based on the electrical angular frequency by integration, factor construction of a correction factor based on the electrical phase by a trigonometric function, and setting a value to apply an excitation setting value using the correction factor to generate a corrected excitation setting value.

[0019] This method is advantageously based on restrictions in the design of the freedom of movement (degrees of freedom) of the vibrating mass and its resonance frequency (here the electrical angular frequency) compared to the excitation unit.

[0020] The actual position of the offset of the vibrating mass detected by means of offset detection is converted into a vector with the detected offset on the abscissa and the velocity of the vibrating mass formed by means of velocity construction on the ordinate, as the differential of the offset according to the following formula:

[0021]

[0022] Where v is the velocity, x is the detected offset, and t is the time.

[0023] The mechanical phase generated by the phase generation is advantageously obtained, for example, by means of an arctan2 function based on the offset and the speed, according to the following formula

[0024] θ m =arctan2(x,v)

[0025] Among them, θ m is the mechanical phase, v is the velocity, and x is the offset.

[0026] The normalized speed for generating the mechanical phase is preferably selected as the speed.

[0027] By means of the phase correction of the mechanical phase, a corrected phase is advantageously generated continuously via the correction value.

[0028] For the frequency construction of electrical angle frequency, replace P (proportional) regulation (with K p Gain component) can also be adjusted using PI (proportional integral) based on the corrected phase (with K p Gain component and integral component I) or PID (proportional integral derivative) regulation (with K p Gain component, integral component I and differential component D), which can improve the quality of P regulation in the sense of more control quality.

[0029] The resulting electrical angular frequency can also be used as the current vibration frequency (required resonance frequency) or the last current vibration frequency (last requested resonance frequency). Therefore, there is no need for targeted learning of the adjustment.

[0030] For phase generation of the electrical angular frequency, the electrical angular frequency is advantageously integrated.

[0031] The correction factor is constructed based on the electrical phase using trigonometric functions, for example using the sine function according to the formula

[0032] kF=sin(θel)

[0033] Among them, k F is the correction factor, θ el is the electrical phase.

[0034] By applying the setpoint value, the excitation setpoint value as the electrical value of the vibration-generating force of the excitation unit for exciting the vibration mass is corrected by a correction factor, so that for the resonance to be achieved between the excitation unit and the vibration mass, a corrected electrical value for the vibration-generating force is generated as a corrected excitation setpoint value.

[0035] With this corrected excitation setpoint, for example, the electromagnet is electrically excited by the excitation unit, which produces a corresponding resonance of the excitation unit and the vibrating mass.

[0036] Advantageous embodiments of the resonance method are specified in the dependent claims.

[0037] In a first advantageous embodiment of the resonance method, the resonance method comprises the following step: speed normalization of the speed to a normalized speed using the electrical angular frequency, wherein the speed can be divided by the electrical angular frequency.

[0038] In order to advantageously map the speed to the electrical angular frequency, the speed is converted into the normalized speed based on the electrical angular frequency according to the formula

[0039]

[0040] Where vn is the normalized velocity, ω el is the electrical angular frequency, x is the offset, and t is time.

[0041] In a further advantageous embodiment of the resonance method, for the phase correction, the correction value is the fed-back electrical phase and the fed-back electrical phase can preferably be subtracted from the mechanical phase.

[0042] From a control perspective, a corrected phase is thus established, wherein the corrected mechanical phase is adjusted until the corrected phase assumes a value of approximately zero.

[0043] Taking into account the signs of the mechanical phase angle and the electrical phase angle, it is also possible to add the electrical phase, which is fed back as a correction value in the control loop for the mechanical phase, to the mechanical phase.

[0044] In a further advantageous embodiment of the resonance method, an initial angular frequency is predetermined or the last known electrical angular frequency is used for initializing the method.

[0045] In order to initialize the resonance method, for example, at the start of the method, the initial angular frequency can be preset, for example, as a parameter which already corresponds to the desired resonance frequency, at the method initialization.

[0046] This is also advantageous because, for example, when a disturbance occurs or when the control is restarted after a failure of the resonance method, the last known electrical angular frequency is returned to.

[0047] In a further advantageous embodiment of the resonance method, the mechanical phase is determined between the deflection amplitude of the deflection and the speed or as the phase between the deflection amplitude of the deflection and the deflection.

[0048] The offset amplitude can be calculated according to the formula

[0049]

[0050] Where xa is the offset amplitude, x is the offset, and v is the velocity.

[0051] The normalized speed for determining the deflection amplitude is preferably selected as the speed.

[0052] In a further advantageous embodiment of the resonance method, for deflection detection, a deflection signal is detected by a deflection measuring device and corrected by a DC component as a function of the position of the deflection measuring device relative to the seismic mass, wherein the DC component is predetermined by a DC component parameter or determined by a DC component high-pass filter.

[0053] The deflection measuring device measures the deflection of the seismic mass relative to its rest position and provides this deflection in a deflection signal for further processing by a resonance method.

[0054] By means of the DC component parameter or the DC component high-pass filter, the offset measurement value associated with the offset signal and the installation position of the offset measuring device can be corrected.

[0055] In a further advantageous embodiment of the resonance method, the excitation setpoint value is a setpoint current and the corrected excitation setpoint value is a corrected setpoint current.

[0056] The excitation setpoint as the electrical value of the force generating the vibration, and the corrected excitation setpoint as the corrected electrical value of the force for generating the vibration, for example by driving an electromagnet with the aid of an electrical converter, are each advantageously designed as a setpoint current for generating the force-generating oscillating excitation. In principle, a corresponding setpoint voltage is also suitable for this purpose.

[0057] In a further advantageous embodiment of the resonance method, for interference monitoring, the electrical angular frequency is monitored for interference when the excitation unit and the vibrating mass resonate.

[0058] For this purpose, the electrical angular frequency can advantageously be monitored by being below a lower frequency limit of the electrical angular frequency and / or below an upper frequency limit of the electrical angular frequency.

[0059] In order to achieve the above-mentioned purpose, a converter is also proposed, comprising: a detection device designed to detect the offset of a vibration mass, a first construction device designed to generate the velocity of the vibration mass by differentiating the offset, a generation device designed to generate a mechanical phase by phase-generating the offset and the velocity, a correction device designed to phase-correct the mechanical phase by a correction value to form a corrected phase, a second construction device designed to frequency-construct an electrical angular frequency based on the corrected phase by at least one P adjustment, a third construction device designed to phase-generate an electrical phase based on the electrical angular frequency by integration, a fourth construction device designed to factor-construct a correction factor based on the electrical phase by a trigonometric function, and an application device designed to apply an excitation setting value by setting a value using the correction factor to generate a corrected excitation setting value.

[0060] In a first advantageous embodiment of the converter, the converter has a normalization device which is designed to normalize the speed to a normalized speed by means of the electrical angular frequency, wherein the speed can be divided by the electrical angular frequency.

[0061] In a further advantageous embodiment of the converter, for phase correction, the fed-back electrical phase is provided as the correction value and can preferably be subtracted from the mechanical phase.

[0062] In principle, the converter is designed to carry out the resonance method according to the invention described above.

[0063] To achieve the above-mentioned object, an excitation unit is also proposed, which has at least one electromagnet for exciting a vibrating mass, a converter according to the invention for operating the at least one electromagnet, and a deflection measuring device for measuring the deflection of the vibrating mass relative to its rest position.

[0064] The offset measured by the offset measuring device is transmitted to the detection device of the converter for offset detection through an offset signal.

[0065] In an advantageous embodiment of the excitation unit, the excitation unit comprises at least one elastic element, wherein the at least one elastic element is connected to the vibrating mass.

[0066] Solutions with two or more elastic elements are also conceivable here, via which the vibrating mass is mounted in a vibrating manner.

[0067] In order to achieve the above-mentioned object, a vibration system is also proposed, which has an excitation unit and a vibration mass according to the present invention.

[0068] In an advantageous embodiment of the vibration system, the vibration system is designed as a friction welding device or a transmission device.

[0069] Transport devices are, for example, conveying devices for transporting material (so-called vibrators or vibrating conveyors), which transport the goods on a vibrating conveyor belt.

[0070] The above characteristics, features and advantages of the present invention and the manner in which they are achieved will become clearer and more easily understood with reference to the following description of the embodiments explained in more detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] Figure 1 shows a structural diagram of the resonance method according to the present invention,

[0072] Figure 2 A schematic diagram showing the regulation of the resonance method according to the present invention, and

[0073] Figure 3 A schematic diagram of a friction welding device is shown having a converter according to the invention, an excitation unit according to the invention, and a vibration system according to the invention. DETAILED DESCRIPTION

[0074] Figure 1 The structural diagram of the resonance method 1 according to the invention is shown, which has method steps for resonating an excitation unit having a vibrating mass.

[0075] During deflection detection 5, the deflection of the seismic mass is detected. The deflection signal detected for this purpose by the deflection measuring device can be corrected by a DC component, depending on the installation position of the deflection measuring device relative to the seismic mass, wherein the DC component is predetermined by a DC component parameter 34 or determined by a DC component high-pass filter 19.

[0076] By differentiating the offset, the velocity of the vibrating mass is formed during velocity construction 6, and the velocity is converted into a normalized velocity based on the electrical angular frequency by dividing the velocity by the electrical angular frequency.

[0077] During phase generation 7 , a mechanical phase is generated based on the offset and the velocity.

[0078] The mechanical phase is converted into a corrected phase by a correction value via phase correction 8. The correction value is the electrical phase fed back into the control loop, which is preferably subtracted from the mechanical phase.

[0079] The frequency build-up 9 of the electrical angular frequency is achieved by at least one P regulation based on the corrected phase. For the frequency build-up 9, the P regulation can also be in the form of a PI regulation or a PID regulation.

[0080] For the process initialization 16 , an initial electrical angular frequency can be preset or the last known electrical angular frequency can be used.

[0081] Furthermore, the electrical angular frequency can be used to monitor disturbances in the resonance of the excitation unit and the vibrating mass for interference monitoring 33. Typical causes of disturbances can be, for example, mechanical defects in the vibration of the vibrating mass, which can cause the desired electrical angular frequency to be too low or too high, necessitating interruption of the resonance process.

[0082] In the phase generation 10 of the electrical phase, integration is achieved based on the electrical angular frequency.

[0083] During factor construction 11 of the correction factor, the excitation setpoint is corrected to a corrected excitation setpoint using trigonometric functions based on the electrical phase and during setpoint application 12 using the correction factor.

[0084] Figure 2 A schematic control diagram of a resonance method 1 according to the invention is shown. In this case, the resonance method 1 can be performed by a converter, in particular by a control unit of the converter.

[0085] The detection device 21 is designed to detect the offset x of the vibration mass 5. Depending on the installation position of the offset measuring device relative to the vibration, the offset signal detected as offset x by the offset measuring device is corrected with a DC component by the high-pass filter device 37 of the DC component high-pass filter 19.

[0086] The first building device 22 differentiates the displacement x into the velocity v of the vibrating mass by means of the velocity building device 6. By dividing the velocity v by the electrical angular frequency ω el , based on the returned electrical angular frequency ω el In the speed normalization 15 , the speed v is further converted into a normalized speed vn by a normalization device 35 .

[0087] The generating device 23 is designed to form a mechanical phase θ m The phase of , which is realized based on the offset x and the velocity v.

[0088] The correction device 24 is designed for the mechanical phase θ m Phase correction 8, where the mechanical phase θ mBy the correction value k θ is converted into a corrected phase θ k The electrical phase of the feedback θ el is used as the correction value k θ , where the mechanical phase θ m Subtract the feedback electrical phase θ from el .

[0089] The second construction device 25 is designed to be based on the corrected phase angle θ k Adjust the electrical angular frequency ω with the help of P el Frequency construction 9 is performed, and P regulation can also be PI regulation or PID regulation. Electrical angular frequency ω el This is now fed back to the normalization device 35 for speed normalization 15 .

[0090] For method initialization 16, follow the initial electrical angular frequency ω in It can be preset by the initialization device 36.

[0091] By means of the third construction device 26, based on the electrical angular frequency ω el Realize electrical phase θ el The phase of θ is generated as 10. At this time, the electrical phase θ el is fed back to the correction device 24 for phase correction 8 .

[0092] Correction factor k F The factor 11 is constructed by the fourth construction device 27 based on the electrical phase angle θ el This is performed with the help of trigonometric functions.

[0093] The application device 28 is designed for applying a correction factor k F The set current I S The excitation setting value 13 in the form of the setting value is applied 12, generating a corrected setting current I sk In particular, the corrected excitation setting current I sk to operate the electromagnet included in the excitation unit and excite the vibration mass to resonate.

[0094] Figure 3 A schematic diagram of a friction welding device 32 is shown having a converter 20 according to the invention, an excitation unit 4 according to the invention, and a vibration system 2 according to the invention.

[0095] The vibration system 2 is designed here, for example, as a friction welding device 32 having an excitation unit 4 and a vibration mass 3 .

[0096] A first fastening device 41 for a first workpiece 43 is arranged on the vibrating mass 3. The vibrating mass 3 with the first fastening device 41 and the first workpiece 43 is mounted so as to be able to vibrate.

[0097] The second workpiece 44 is connected to a second fastening device 42 directly opposite the first workpiece 43. The second workpiece 44 on the second fastening device 42 is firmly fixed relative to the first workpiece 43 and is not mounted so as to be able to vibrate.

[0098] The excitation unit 4 for exciting vibrations in the vibrating mass 3 comprises a transducer 20, an electromagnet 29, a further electromagnet 30, first and second elastic elements 38, 39 for vibration mounting the vibrating mass 3, and a deflection measuring device 18. The deflection measuring device 18, which is connected to the transducer 20, transmits a deflection signal having a measured actual value of the deflection.

[0099] The deflection relative to the rest position 31 of the seismic mass 3 is measured by the deflection measuring device 18 .

[0100] The control method according to the present invention can be carried out by the converter 20 , in particular by the control unit 40 of the converter 20 .

[0101] During operation of the friction welding device 32, the first workpiece 43, which is fixed to the first fastening device 41 of the vibration block 3, is set in resonance with the excitation unit 4. The first workpiece 43, which begins to vibrate, rubs against the second workpiece 44, which is firmly fixed and does not vibrate, wherein friction heat is generated and the two workpieces 43, 44 are welded to each other in an energy-saving manner and with high production quality.

Claims

1. A resonance method (1) for a vibration system (2), the vibration system (2) being used to resonate an excitation unit (4) having a vibration mass (3), the resonance method (1) comprising the following steps: - performing an offset detection (5) of the offset (x) of the vibrating mass (3), wherein For the offset detection (5), an offset signal (17) is detected by an offset measuring device (18), and the offset signal (17) is corrected with a DC component relative to the vibrating mass (3) depending on the installation position of the offset measuring device (18), wherein the DC component is predetermined by a DC component parameter (34) or is obtained by a DC component high-pass filter (19). - velocity construction (6) of the velocity (v) of the vibrating mass (3) by differentiating the displacement (x), - Use the offset (x) and the velocity (v) to perform mechanical phase (θ m )’s phase generation (7), - Using the correction value (k θ ) to the mechanical phase (θ m ) to perform phase correction (8) to obtain the corrected phase (θ k ), - Based on the corrected phase (θ k ) is adjusted by at least one P to adjust the electrical angular frequency (ω el ) frequency construction (9), -Based on the electrical angular frequency (ω el ) is integrated to perform the electrical phase (θ el ) phase construction, -Based on the electrical phase (θ el ) Correction factor (k) is obtained by trigonometric function F ) factor construction (11), and - Using the correction factor (k F ) performs setting value application (12) of the excitation setting value (13) to generate a corrected excitation setting value (14).

2. The resonance method (1) according to claim 1, comprising the following steps: using the electrical angular frequency (ω el ) to normalize the speed (v) n ) is normalized by the velocity (15), where Divide the velocity (v) by the electrical angular frequency (ω el ).

3. The resonance method (1) according to claim 1 or 2, wherein: In order to perform the phase correction (8), the correction value (k θ ) is the electrical phase of the feedback (θ el ), and from the mechanical phase (θ m ) minus the electrical phase of the feedback (θ el ).

4. The resonance method (1) according to claim 1 or 2, wherein: To initialize the method (16), the initial angular frequency (ω in ) or use the last known electrical angular frequency (ω el ).

5. The resonance method (1) according to claim 1 or 2, wherein: The mechanical phase (θ m ) is determined between the offset amplitude of the offset (x) and the velocity (v), or the mechanical phase (θ m ) is determined as the phase between the offset amplitude of the offset (x) and the offset (x).

6. The resonance method (1) according to claim 1 or 2, wherein: The excitation setting value (13) is the setting current (I s ), and the corrected excitation setting value (14) is the corrected setting current (I sk ).

7. The resonance method (1) according to claim 1 or 2, wherein: In order to perform interference monitoring (33), the electrical angular frequency (ω el ).

8. A converter (20) comprising: - a detection device (21) designed for deflection detection (5) of the deflection (x) of the vibrating mass (3), wherein: For the offset detection (5), an offset signal (17) is detected by an offset measuring device (18), and the offset signal (17) is corrected with a DC component relative to the vibrating mass (3) depending on the installation position of the offset measuring device (18), wherein the DC component is predetermined by a DC component parameter (34) or is obtained by a DC component high-pass filter (19). a first construction device (22) designed to carry out a velocity construction (6) of the velocity (v) of the vibrating mass (3) by differentiation of the displacement (x), - a generating device (23) designed to generate a mechanical phase (θ) using said displacement (x) and said velocity (v) m )’s phase generation (7), - a correction device (24) designed to utilize the correction value (k θ ) to the mechanical phase (θ m ) to perform phase correction (8) to obtain the corrected phase (θk), - a second construction device (25) designed to generate a phase correction signal based on the phase correction signal (θ k ) is adjusted by at least one P to adjust the electrical angular frequency (ω el ) frequency construction (9), - a third construction device (26) designed to be used based on said electrical angular frequency (ω el ) is integrated to perform the electrical phase (θ el ) phase construction, - a fourth construction device (27) designed to el ) Correction factor (k) is obtained by trigonometric function F ) factor construction (11), and - an application device (28) designed to utilize said correction factor (k F ) performs setting value application (12) of the excitation setting value (13) to generate a corrected excitation setting value (14).

9. The converter (20) according to claim 8, comprising a normalizing device (35) designed to use the electrical angular frequency (ω el ) to normalize the speed (v) n ) is normalized by the velocity (15), where The speed (v) can be divided by the electrical angular frequency (ω el ).

10. The converter (20) according to claim 8 or 9, wherein In order to perform the phase correction (8), the electrical phase (θ el ) is set as the correction value (k θ ), and can be derived from the mechanical phase (θ m ) minus the electrical phase of the feedback (θ el ).

11. An excitation unit (4), comprising: - at least one electromagnet (29) for exciting the vibrating mass (3), - A converter (20) according to any one of claims 8 to 10, for operating the at least one electromagnet (29), and - a deflection measuring device (18) for measuring the deflection (x) of the vibrating mass (3) relative to a rest position (31) of said vibrating mass (3).

12. The excitation unit (4) according to claim 11, comprising at least one elastic element, wherein The at least one elastic element is connected to the vibration block (3).

13. A vibration system (2) comprising an excitation unit (4) and a vibration mass (3) according to claim 11 or 12.

14. The vibration system (2) according to claim 13, embodied as a friction welding device (32) or a transmission device.

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