SU1639938A1 - Method of detecting faulty assembling - Google Patents

Abstract

The invention relates to mechanical engineering and can be used in automated assembly production. The purpose of the invention is to expand the functionality and improve the accuracy of detecting poor-quality assembly by fixing local defects. The method consists in measuring the magnitude of the oscillations of the contact surfaces of the parts to be joined, frequency analysis of the measured oscillations, the results of which determine the assembly errors. During the assembly, oscillations are excited by a single pulse in the parts being joined, and poor-quality assembly is determined from the results of the analysis of response parameters. The excitation of oscillations by a single pulse and the analysis of response parameters are carried out sequentially for a number of coordinate values of the linear relative displacement of parts 1 sludge.

Description

The invention relates to mechanical engineering and can be used in automated assembly production.

The aim of the invention is to enhance the functionality and increase the accuracy of detecting poor-quality assembly due to fixing local defects.

The drawing shows a device for implementing the method.

The device contains a rod-type part 1, which with the help of the robot tong 2 is inserted into the hole of the part 3 mounted on the clamping device 4. The vibration sensor 5 is fixed on the part 3, the output signal of which is fed to the first information input of the key 6. The first and second outputs the key 6 is connected respectively to the inputs of the frequency analyzer 7 and the response analysis block 8. The output of the frequency analyzer 7 is connected to the first input of the microcomputer 9, the second input of which is connected to the first output of the response analysis block 8, and the second output of the response analysis block 8 is connected to the second control input of the key 6. The drum control unit 11 is connected to the output of the displacement converter 10 the third input of the microcomputer 9. The displacement converter 10 is connected with a screw 12 to a drive motor 13. A screw 14 moves a nut 14, which is connected with a slide 16 by means of a bracket 15. The latter is mounted on the rail 17 vertical displacements and the rod 18 is connected to the gripper 2 of the robot. On the sponge 19 of the gripper 2 of the robot, the coil 21 of the electromagnet with the conductive winding 22 is fixed by means of the bracket 20. In the coil of the electromagnet 21 a core 23 is mounted, which is connected to the sponge 19 by means of a return spring 24. which through the hole in

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the sponge 19 may affect the rod-type part 1. The winding 22 of the electromagnet coil 21 is connected to the first output of the drum control unit 11, and the second output of the drum control unit 11 is connected to the third (control) input of the key 6.

The method is carried out as follows.

Part 1 of the rod type with the help of the robot tongue 2 is vertically inserted into the hole of the part 3 mounted on the clamping device 4. Deviation of the dimensions and shape of the contact surfaces leads to a change in the elastic connections between them and to a change in the damping factor. The vibrations of the contact surfaces are converted by the vibration sensor 5 into an electrical signal. The electrical signal from the vibration sensor 5 through the switch 6 is fed to the input of the frequency analyzer 7, in which the magnitude of each frequency component of the electrical signal is determined.

Based on the results of the frequency analysis of the oscillations, the assembly defects in the microcomputer 9 are determined. Assembly defects are determined by comparing the nominal values of the frequency components stored in the memory of the microcomputer 9 with the actual values of the frequency components obtained in the frequency analyzer 7.

The relative vertical movement of the part 1 into the hole of the part 3 is carried out as follows. The drive motor 13 transmits the rotation to the screw 12. The rotation of the latter leads to the translational movement of the nut 14 and the bracket 15 rigidly connected with it, the slide 16 and the rod 18 with the gripper 2 of the robot. The slider 16 is mounted on the guide 17 of the vertical displacements.

Information on moving the part 1 in the vertical direction is generated as follows. The rotation of the screw 12 by the displacement transducer 10 is converted into an electrical signal proportional to the vertical movement of the workpiece 1. From the output of the displacement transducer 10, the electrical signal goes to the third input of the microcomputer 9 and to the input of the drum control unit 11. Based on the obtained information on the vertical movement of the part 1, the drum control unit 11, in accordance with a predetermined range of movements, generates a control action, i.e. connects briefly

supply voltage to the winding 22 of the coil 21 of the electromagnet. Under the action of electromagnetic forces, the core 23 with the hammer 25 through the hole in the sponge of the gripper 2 causes

blow to parts 1 rod type. After turning off the power, the return spring 24 moves the core 23 with the hammer 25 to its original position.

The shock pulse in the connected parts x 1 and 3 excites free oscillations, which the vibration sensor 5 converts into an electrical signal.

Simultaneously with the control action on the drummer 25 control unit 11

the drummer issues a signal to the third control input of the key 6, allowing the passage of electrical signals from the vibration sensor 5 to the input of the response analysis block 8 and prohibiting the passage of these signals to

frequency analyzer input 7.

In block 8 of the analysis of the response, the determination of the damping factor A of freely damped oscillations is carried out. The value of the decrement And from the first output

The response analysis block 8 is fed to the second input of the microcomputer 9, where it is compared with the reference value of the damping factor Aj corresponding to the actual contact area and contact pressure

for the current value of the coordinate of the linear relative movement of the parts. Simultaneously from the second output of the response analysis unit 8, a signal is output to the second control input of the key 6, and the electrical

the signal from the vibration sensor 5 is disconnected from the input of the response analysis block 8 and connected to the input of the frequency analyzer 7.

The coordinate value of the linear relative displacement of parts 1 and 3 is formed in the displacement converter 10 and fed to the third input of the microcomputer 9, the memories of which for each value of the coordinate of the linear relative displacement of parts store reference values of the damping factor Av.

The next cycle for determining the damping factor A is carried out similarly for the next value

coordinates of the linear relative movement of parts.

In the intervals between the determination of the damping factor A, frequency analysis and determination of

each frequency component of the electrical signal.

Claims (1)

The method of determining the poor-quality assembly, which consists in measuring the magnitude of the vibrations of the contact surfaces of the parts to be connected and then determining the assembly errors based on the results of the frequency analysis of these oscillations, characterized in that, in order to enhance the functionality and improve the accuracy of detecting poor-quality assembly by fixing local defects in progress 0 The assemblies additionally in one of the parts initiate oscillations with a single pulse, according to the results of the analysis of response parameters which determine a poor-quality assembly, while the excitation of oscillations with a single pulse and the analysis of response parameters are carried out sequentially for a number of coordinate values of the linear relative displacement of the assembled parts.