Precision compensation method of welding turntable for welding robot

Abstract

The invention discloses a precision compensation method of a welding turntable for a welding robot, which comprises the following steps of: mounting a laser sensor on the rear side of an over-travel limiting block of the welding turntable, moving the welding turntable to an original point correction position, carrying out zero calibration on the laser sensor, outputting the original point position and the actual detection data of the welding turntable in real time by the laser sensor, the PLC performs deviation calculation on original point calibration data of the laser sensor, and a compensation value is transmitted to an internal variable of the welding robot in real time through a profinet network; the welding robot transmits the rotation angle to a variable, compensation is achieved by modifying an external shaft compensation value, and the welding robot resets the original point of the welding rotary table; and the laser sensor automatically detects the position of the welding rotary table, the PLC performs original point checking after receiving original point reset of the welding robot, a checking result is output, and the welding robot completes correction. The actual positioning precision of the rotary table can be monitored in real time, the maintenance difficulty is reduced, and visual control over the precision of the welding rotary table is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of welding robots, and in particular relates to a precision compensation method for a welding turntable used for a welding robot. Background Art

[0002] A welding robot is an industrial robot used to perform welding tasks (including cutting and spraying). It combines robotics and welding technology, and uses programming to achieve automated welding operations. It can replace manual labor in various complex working environments to perform high-precision and high-efficiency welding operations. The welding turntable for welding robots is an auxiliary device specially designed for welding robots. It can achieve multi-angle rotation so that the welding robot can perform welding operations at different angles and positions. The multi-angle rotation enables the welding robot to align the welding part more accurately to ensure the accuracy and consistency of welding. The RV reducer is a precision reducer with a large reduction ratio. Due to its high cost-effectiveness, high precision, large reduction ratio, and high rigidity, it is one of the best ways to precisely position the reducer for welding turntables and welding robots. However, the high-precision coupling is an optical axis design, which is easy to slip against each other in extreme overload conditions, resulting in positioning deviation of the welding turntable, which requires a lot of time for repositioning and fixture debugging.

[0003] The welding turntable in the prior art, especially the welding turntable used for large-tonnage welding fixtures, needs emergency braking in emergency situations or when there is an abnormal power outage during high-speed operation of the welding turntable, due to the large mass and inertia of the welding fixture, the precision RV reducer will be overloaded at the coupling under the huge braking torque, and the coupling will slide slightly against each other. Therefore, the origin position often deviates after "emergency stop", causing the equipment to spend a lot of time to correct the origin position and confirm the welding position.

[0004] At present, in the industry, the commonly used positioning solution for adjusting the precision of the welding turntable of the welding robot is mechanical alignment, in which the welding turntable slowly resets its origin near the origin, relying on visual methods, proximity switches or mechanical pin positioning inspections; however, the above adjustment methods are slow and low in precision, and cannot compensate for the position accuracy online; the positioning accuracy is determined by the positioning pin accuracy and the proximity switch, and the operator needs to move to the welding turntable origin position to perform the positioning correction; the poor and narrow working environment can easily cause large positioning errors, affecting work efficiency. Summary of the invention

[0005] In order to solve the above problems, an object of the present invention is to provide a precision compensation method for a welding turntable for a welding robot.

[0006] In order to achieve the above-mentioned invention object, the present invention adopts the following technical scheme: A method for compensating the accuracy of a welding turntable for a welding robot comprises the following steps: S1. Install the laser sensor on the rear side of the overtravel limit block of the welding turntable so that the laser beam it emits can accurately detect the motion state of the welding turntable; first, the welding turntable moves to the origin calibration position and the laser sensor is zeroed; the welding robot starts to enter the automatic program, the welding turntable moves to the origin stop position, the laser sensor outputs the origin position and the actual detection data of the welding turntable in real time, the PLC controller performs A / D conversion of the detection data, and calculates the angle of the welding turntable. After the welding robot outputs the completion signal, the PLC controller reads the A / D data and calculates the deviation of the origin calibration data of the laser sensor. When the tolerance is exceeded, the PLC controller outputs the compensation value, which is transmitted to the internal variables of the welding robot in real time through the profinet network; The calculation formula of the deviation angle of the welding turntable by the PLC controller is: Deviation angle = arc length l / Circumference C*360° Deviation value = origin angle - positioning angle The arc length l Detected by laser sensor; S2. The welding robot runs the compensation program. The welding robot uses the 16-bit data format as the rotation angle to transmit to the variable. The compensation is achieved by modifying the external axis compensation value. The welding robot automatically starts the welding turntable program and resets the welding turntable origin. The laser sensor automatically detects the position of the welding turntable, and the PLC controller reads the data for A / D conversion. After the PLC controller receives the welding robot's origin reset, the PLC controller performs origin calibration and outputs the calibration result. The welding robot completes the correction.

[0007] Furthermore, in the above-mentioned step S2, each time the welding turntable of the welding robot is positioned, a positioning completion signal is output, and the welding robot reads the deviation value to determine whether correction is required; if it exceeds the deviation setting, an origin correction is performed, the welding robot moves to the compensated working position, and the compensation content and time are recorded.

[0008] Due to the adoption of the above-mentioned technical solution, the present invention has the following advantages: The accuracy compensation method of the welding turntable for the welding robot of the present invention outputs the difference between the welding turntable and the positioning in real time through the laser sensor during the automated operation process. The welding robot automatically obtains the actual position accuracy of the welding turntable when it runs to the specific position of the welding turntable. When the positioning position of the welding turntable exceeds the set deviation, the welding robot can automatically compensate for the position error, and timely eliminate the positioning error caused by mechanical sliding or external process interference, thereby saving a large amount of abnormal downtime for actual production, especially when the automated production line stops abnormally and the welding turntable deviates from the origin position after emergency braking, it can be quickly confirmed and corrected. It can not only solve the problems of poor positioning and long recovery time that often occur in emergency situations, but also monitor the actual positioning accuracy of the turntable in real time, determine whether the wear clearance of the welding turntable exceeds the requirement, reduce the difficulty of maintenance, and realize visual control of the welding turntable accuracy, which has good promotion and application value in actual production. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a PLC control flow chart of the precision compensation method of the welding turntable for the welding robot of the present invention; Figure 2 The invention discloses a control flow chart of a welding robot for use with a welding turntable according to the present invention. DETAILED DESCRIPTION

[0010] The technical solution of the present invention is further described in detail below through the drawings and embodiments.

[0011] like Figure 1 , 2 As shown, the accuracy compensation method of the welding turntable for the welding robot includes the following steps: S1. Install the laser sensor on the rear side of the overtravel limit block of the welding turntable so that the laser beam it emits can accurately detect the motion state of the welding turntable, which is used to check the linear distance of the welding turntable offset; first, the welding turntable moves to the origin calibration position and calibrates the laser sensor to zero; the welding robot starts to enter the automatic program, the welding turntable moves to the origin stop position, the laser sensor outputs the origin position and the actual detection data of the welding turntable in real time, the PLC controller performs A / D conversion of the detection data, and calculates the angle of the welding turntable. After the welding robot outputs the completion signal, the PLC controller reads the A / D data and calculates the deviation of the origin calibration data of the laser sensor. When the tolerance is exceeded, the PLC controller outputs the compensation value, which is transmitted to the welding robot in real time through the communication protocol profinet network. After the welding robot obtains the deviation value, it calculates the pulse value that needs to be compensated and writes it into the origin compensation variable; The calculation formula of the deviation angle of the welding turntable by the PLC controller is: Deviation angle = arc length l / Circumference C*360° Deviation value = origin angle - positioning angle The arc length l Detected by laser sensor; S2, the welding robot runs the compensation program, and the welding robot uses the 16-bit data format as the rotation angle to transmit to the variable; the welding robot variables in the robot automatic program are superimposed on the origin data of the motor. After the data is completed, the welding turntable automatically locates the origin according to the new data, and the compensation is achieved by modifying the external axis compensation value. The welding robot automatically starts the welding turntable program and resets the welding turntable origin; the laser sensor automatically detects the position of the welding turntable, and the PLC controller reads the data for A / D conversion; after the PLC controller receives the welding robot origin reset, the PLC controller performs origin calibration, outputs the calibration result, and the welding robot completes the correction; Each time the welding robot positions the welding turntable, it outputs a positioning completion signal and reads the deviation value to determine whether correction is needed. If it exceeds the deviation setting, the origin correction is performed and the welding robot moves to the compensated working position. The compensation content and time of the welding turntable are recorded for equipment maintenance data analysis.

[0012] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A precision compensation method for a welding turntable for a welding robot, characterized by: It includes the following steps: S1. Install the laser sensor on the rear side of the overtravel limit block of the welding turntable so that the laser beam it emits can accurately detect the motion state of the welding turntable; first, the welding turntable moves to the origin calibration position and the laser sensor is zeroed; the welding robot starts to enter the automatic program, the welding turntable moves to the origin stop position, the laser sensor outputs the origin position and the actual detection data of the welding turntable in real time, the PLC controller performs A / D conversion of the detection data, and calculates the angle of the welding turntable. After the welding robot outputs the completion signal, the PLC controller reads the A / D data and calculates the deviation of the origin calibration data of the laser sensor. When the tolerance is exceeded, the PLC controller outputs the compensation value, which is transmitted to the internal variables of the welding robot in real time through the profinet network; The calculation formula of the deviation angle of the welding turntable by the PLC controller is: Deviation angle = arc length l / Circumference C*360° Deviation value = origin angle - positioning angle The arc length l Detected by laser sensor; S2. The welding robot runs the compensation program. The welding robot uses the 16-bit data format as the rotation angle to transmit to the variable. The compensation is achieved by modifying the external axis compensation value. The welding robot automatically starts the welding turntable program and resets the welding turntable origin. The laser sensor automatically detects the position of the welding turntable, and the PLC controller reads the data for A / D conversion. After the PLC controller receives the welding robot's origin reset, the PLC controller performs origin calibration and outputs the calibration result. The welding robot completes the correction.

2. The accuracy compensation method for a welding turntable for a welding robot according to claim 1 is characterized in that: In step S2, each time the welding robot's welding turntable is positioned, a positioning completion signal is output, and the welding robot reads the deviation value to determine whether correction is required; if it exceeds the deviation setting, an origin correction is performed, the welding robot moves to the compensated working position, and the compensation content and time are recorded.

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