JP2008272814A5 - - Google Patents

Claims (9)

A robot having a plurality of drive shafts and mounting a welding torch at the tip;
A welding power source connected to the welding torch and outputting a welding current to the welding torch;
A sensor that is mounted in the vicinity of the welding torch and detects the position of a welding line of a workpiece in advance of the welding torch;
A sensor control device connected to the sensor and controlling the sensor;
A robot control device that controls the drive shaft of the robot according to teaching position data taught in advance and is connected to the welding power source and the sensor control device and inputs / outputs information; and the position of the welding line by the sensor In a robot system that performs welding work by tracking control that corrects the position of the welding torch while detecting
The robot control device includes sensor information input means for inputting the position of the welding line detected by the sensor from the sensor control device;
Positional relationship data representing the positional relationship between the welding torch and the sensor;
Coordinate conversion means for converting the position of the welding line detected by the sensor using the current position of the robot and the positional relationship data into a position in a coordinate system based on the robot;
A detection position buffer for storing a predetermined number of time-series position data converted by the coordinate conversion means;
Recording trajectory data for preliminarily storing the position of the welding line detected by the sensor;
Using the positional relationship data, first position data corresponding to the current tip position of the welding torch is extracted from position data in the detection position buffer, and corresponding to the first position data from the recording trajectory data. Correction amount calculating means for extracting second position data and calculating a correction amount of the position of the welding torch based on a difference between the first position data and the second position data ;
A robot system comprising command position calculation means for calculating a command position of the robot corrected from the correction amount and the teaching position data.   The correction amount calculating means determines whether the sensor and the welding torch pass the same point on the welding line based on the moving speed of the welding torch and the positional relationship data when extracting the first position data. 2. A time difference is obtained, and position data stored in a storage location that is backed by the time difference from the storage location of the current position of the sensor in the detection position buffer is used as the first position data. The robot system described. The robot control device includes a delay parameter setting unit that sets a value corresponding to a delay time from when the robot receives a movement command until the robot reaches a command position as a parameter and inputs the parameter to the correction amount calculation unit.
The correction amount calculating means determines whether the sensor and the welding torch pass the same point on the welding line based on the moving speed of the welding torch and the positional relationship data when extracting the first position data. A time difference is obtained, and in the detection position buffer, position data stored in a storage location that is backed by the sum of the parameter setting value and the time difference from the storage location of the current position of the sensor is the first position data. The robot system according to claim 1, wherein:   The correction amount calculation means obtains position data having the smallest difference from the first position data from the position data stored in the recording trajectory data at the time of extracting the second position data. 4. The robot system according to claim 1, wherein the robot system is position data. The robot controller corrects the position of the welding torch while detecting the position of the welding line using position data extracted from the recorded trajectory data, and adds the position of the welding line in addition to a tracking mode in which welding operation is performed. A trajectory recording mode for storing the recorded trajectory data,
The robot system according to any one of claims 1 to 3, wherein switching between the tracking mode and the locus recording mode is performed.   The robot control device stores a plurality of types of the recording trajectory data according to a plurality of types of the welding lines in the trajectory recording mode, and selects from the plurality of types of the recording trajectory data stored in the tracking mode. 6. The robot system according to claim 5, wherein the tracking control is performed according to the recorded trajectory data.   The robot control apparatus stores a plurality of types of settings related to the tracking control determined in advance, and performs the tracking control according to a setting selected from the plurality of types of settings stored in the tracking mode. Item 6. The robot system according to Item 5.   The robot system according to claim 6 or 7, wherein the robot control device simultaneously specifies the setting related to the recording trajectory data and the tracking control in the tracking mode. The robot controller, the note of the correction amount of the position of the welding torch in the welding operation performed by the tracking control, any of claims 1 to 3 and outputs to the external storage device after the work is completed The robot system according to claim 1 .