Patent ID: 12194496

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG.1shows a structure chart of the resonance method1according to the invention with method steps for resonant vibration of an excitation unit with a vibrating mass.

During deflection detection5, a deflection of the vibrating mass is detected. A deflection signal detected for this purpose by a deflection measuring apparatus can be corrected by a DC component as a function of the installation location of the deflection measuring apparatus with regard to the vibrating mass, wherein the DC component can be specified by a DC component parameter34or determined by a DC component high-pass filter19.

By differentiating the deflection, a velocity of the vibrating mass is formed during velocity formation6, the velocity being converted into a standardized velocity on the basis of the electrical angular frequency by dividing the velocity by the electrical angular frequency.

In phase position generation7, a mechanical phase position is generated on the basis of the deflection and the velocity.

Via phase position correction8, the mechanical phase position is converted into a corrected phase position by a correction value. In this case, the correction value is the electrical phase position fed back in a control loop, wherein preferably the fed-back electrical phase position is subtracted from the mechanical phase position.

Frequency formation9of an electrical angular frequency takes place by means of at least one P-regulation on the basis of the corrected phase position. For frequency formation9, the P-regulation can also be designed as a PI-regulation or as a PID-regulation.

For a method initialization16, an initial angular frequency can be specified or the last known electrical angular frequency can be used.

Furthermore, the electrical angular frequency can be monitored for faults in the resonant vibration of the excitation unit and the vibrating mass. Typical faults can have their origins, for example, in mechanical defects during the vibration of the vibrating mass, so that the required electrical angular frequency can become too low or too high and the resonance method may have to be interrupted.

In phase position formation10of an electrical phase position, integration takes place on the basis of the electrical angular frequency.

During factor formation11of a correction factor, a trigonometric function on the basis of the electrical phase position is used and the correction factor corrects an excitation setpoint value to a corrected excitation setpoint value during setpoint value application12.

FIG.2shows a diagrammatic regulation representation of the resonance method1according to the invention. In this case, the resonance method1can be carried out by a converter, in particular by a regulation unit of the converter.

A detection means21is designed for deflection detection5of a deflection x of the vibrating mass. A deflection signal detected as deflection x by a deflection measuring apparatus is, as a function of the installation location of the deflection measuring apparatus with regard to the vibrating mass, corrected by means of a high-pass means37of a DC component high-pass filter19by a DC component.

A first forming means22differentiates the deflection x by means of the velocity formation6into a velocity v of the vibrating mass. The velocity v is furthermore converted into a velocity standardization15by a standardization means35in a standardized velocity vnon the basis of a fed-back electrical angular frequency ωelby dividing the velocity v by the electrical angular frequency ωel.

A generating means23is designed for phase position generation7of a mechanical phase position Θmwhich takes place on the basis of the deflection x and the velocity v.

A correction means24is designed for phase position correction8of the mechanical phase position Θm, the mechanical phase position Θmbeing converted into a corrected phase position Θkby means of a correction value kΘ. A fed-back electrical phase position Θelis used as the correction value kΘ, the fed-back electrical phase position Θelbeing subtracted from the mechanical phase position Θm.

A second forming means25for frequency formation9of the electrical angular frequency ωelis designed on the basis of the corrected phase position Θkby means of here a P-regulation, which may also be a PI-regulation or a PID regulation. The electrical angular frequency ωelis returned at this point to the standardization means35for velocity standardization15.

An initial angular frequency ωincan be specified by an initialization means36for method initialization16.

By means of a third forming means26, a phase position formation10of the electrical phase position Θeltakes place by means of integration on the basis of the electrical angular frequency ωel. At this point, the electrical phase position Θelis returned to the correction means24for phase position correction8.

From a fourth forming means27, a factor formation11of a correction factor kFis carried out by means of a trigonometric function based on the electrical phase position Θel.

An application means28, designed for the setpoint value application12of an excitation setpoint value13in the form of a setpoint current ISwith the correction factor kF, generates a corrected excitation setpoint value14in the form of a corrected setpoint current ISk. In particular, this corrected setpoint current ISkis used to operate an electromagnet which is comprised by the excitation unit and excites resonant vibration of the vibrating mass.

FIG.3shows a diagrammatic view of a friction welding apparatus32with the converter20according to the invention, the excitation unit4according to the invention and the vibration system2according to the invention.

Here, the vibration system2is designed by way of example, as a friction welding apparatus32with the excitation unit4and a vibrating mass3.

A first fastening means41for a first workpiece43is arranged on the vibrating mass3. The vibrating mass3with the first fastening means41and the first workpiece43is mounted so as to be able to vibrate.

Directly opposite the first workpiece43, a second workpiece44is connected to a second fastening means42. In this case, the second workpiece44on the second fastening means42is fixed in a fixed manner with regard to the first workpiece43and is not mounted so as to be able to vibrate.

The excitation unit4for the vibration excitation of the vibrating mass3comprises the converter20, an electromagnet29, a further electromagnet30, a first and second spring element38,39for mounting of the vibrating mass3so as to be able to vibrate, a deflection measuring apparatus18and a deflection signal transmitted from the deflection measuring apparatus18to the converter20, which deflection signal has a measured actual value of deflection.

The deflection is measured by means of the deflection measuring apparatus18with regard to a resting position31of the vibrating mass3.

The control method according to the invention can be carried out by means of the converter20, in particular by means of the regulation unit40of the converter20.

During operation of the friction welding apparatus32, the first workpiece43fastened to the first fastening means41of the vibrating mass3is set into resonant vibrations with the excitation unit4. The first workpiece43, which is set into vibrations, rubs against the fixed second workpiece44which is not able to vibrate, frictional heat being generated and both workpieces43,44being welded to one another in an energy-efficient manner and in a high production quality.