Offline teaching method

• US 8,872,070 B2
• Filed: 07/19/2011
• Issued: 10/28/2014
• Est. Priority Date: 08/09/2010
• Status: Active Grant

• Current Assignee: Klaus Schmidt
• Original Assignee: Kobe Steel Limited
• Inventors: Hida, Masatoshi, Hara, Susumu, Izumi, Toshiyuki
• Primary Examiner(s): PAIK, SANG YEOP
• Application Number:
  US13/185,823
• Publication Number:
  US 20120031886A1
• Time in Patent Office: 1,197 Days
• Field of Search: 219/136, 219/137.R
• US Class Current: 219/137.R
• CPC Class Codes: B23K 37/0452 Orientable fixtures B23K37/0461 takes precedence
• CPC Class Codes: B23K 9/095 Monitoring or automatic control of welding parameters
• CPC Class Codes: B23K 9/1062 with computing means
• CPC Class Codes: B23K 9/1087 Arc welding using remote control
• CPC Class Codes: B23K 9/124 Circuits or methods for feeding welding wire
• CPC Class Codes: G05B 19/4086 Coordinate conversions; Other special calculations
• CPC Class Codes: G05B 19/425 Teaching successive positions by numerical control, i.e. commands being entered to control the positioning servo of the tool head or end effector
• CPC Class Codes: G05B 2219/35091 Feature conversion, from design to process features or else
• CPC Class Codes: G05B 2219/36432 By putting some constraints on some DOF, move within limited volumes, areas, planes, limits motion in x, y or z planes, virtual reality constraints
• CPC Class Codes: G05B 2219/36494 Record position and inclination of tool, wrist

Abstract

A three-dimensional rectangular coordinate system is set in which the direction of a weld line is the Y direction, a direction perpendicular to a surface of a material to be welded is the Z direction, and a direction perpendicular to the Y direction and the Z direction is the X direction. A coordinate system A of X_AY_AZ_A is set as a previous stage coordinate system, which ranges from a previous step to a current step, and a coordinate system B of X_BY_BZ_B is set as a next stage coordinate system, which ranges from the current step to a next step. The weld line is defined by these coordinate systems that use a workpiece as a reference, and an operator specifies the amount of travel of a torch in these workpiece coordinate systems. By this method, offline teaching can be accurately performed in a welding system without requiring skill in operation.

Claims

1. An offline teaching method for performing, on a welding robot, offline teaching of a weld line including a segment, the offline teaching method comprising the steps of:

obtaining, by a computer, a position of a current step of a torch of the welding robot and a position of a next or a previous step;

setting, by the computer, either a previous stage coordinate system ranging from the previous step to the current step or a next stage coordinate system ranging from the current step to the next step by using, if the segment of the weld line is a straight line, an XYZ coordinate system in which a direction of the weld line is a Y direction and a direction perpendicular to a surface of a base material to be welded is a Z direction;

inputting, by an operator, an amount of travel in the set coordinate system;

displaying, by the computer, the torch of the welding robot such that the torch is moved along the weld line in the next stage coordinate system or the previous stage coordinate system by the amount of travel;

selecting, before the step of obtaining, axes of a slider and a positioner on which peripheral coordination is to be performed;

inputting, by the operator, either absence of peripheral axis coordination in the step of inputting the amount of travel or presence of peripheral axis coordination in the step of inputting the amount of travel, and either the attitude of the torch is to be fixed or the attitude of the torch is not to be fixed; and

moving, if the peripheral axis coordination is to be performed, at least either the slider or the positioner by an amount proportional to the amount of travel of the torch relative to the position of the next step,

wherein, if the torch is to be fixed, an angle of the torch is kept the same relative to a positioner setting surface in the coordinate system by setting an angle obtained by subtracting an amount of rotation of the positioner as the angle of the torch, and, if the torch is not to be fixed, the angle of the torch is not changed in the coordinate system.

2. An offline teaching method for performing, on a welding robot, offline teaching of a weld line divided into a plurality of segments by steps, the offline teaching method comprising the steps of:

obtaining, by a computer, a position of a current step of a torch of the welding robot and positions of next and previous steps in order to allow the torch of the welding robot to move along a previous segment or a next segment;

setting, by the computer, a previous stage coordinate system ranging from the previous step to the current step and a next stage coordinate system ranging from the current step to the next step by using, if the segment of the weld line is a straight line, an XYZ coordinate system in which a direction of the weld line is a Y direction and a direction perpendicular to a surface of a base material to be welded is a Z direction or, if the segment of the weld line is an arc, an XCZ coordinate system in which a radial direction of the arc is an X direction, a circumferential direction of the arc is a C direction, and a direction perpendicular to a base material to be welded is a Z direction;

inputting, by an operator, an amount of travel in the set coordinate system;

displaying, by the computer, the torch of the welding robot such that the torch is moved along the weld line in the next stage coordinate system or the previous stage coordinate system by the amount of travel;

selecting, before the step of obtaining, axes of a slider and a positioner on which peripheral coordination is to be performed;

inputting, by the operator, either absence of peripheral axis coordination in the step of inputting the amount of travel or presence of peripheral axis coordination in the step of inputting the amount of travel, and either the attitude of the torch is to be fixed or the attitude of the torch is not to be fixed; and

moving, if the peripheral axis coordination is to be performed, at least either the slider or the positioner by an amount proportional to the amount of travel of the torch relative to the position of the next step,

wherein, if the torch is to be fixed, an angle of the torch is kept the same relative to a positioner setting surface in the coordinate system by setting an angle obtained by subtracting an amount of rotation of the positioner as the angle of the torch, and, if the torch is not to be fixed, the angle of the torch is not changed in the coordinate system.

3. The offline teaching method according to claim 2, wherein, if the amount of travel input by the operator has a negative value, the previous stage coordinate system is automatically selected by the computer and, if the amount of travel has a positive value, the next stage coordinate system is automatically selected by the computer.

4. An offline teaching method for performing, on a welding robot, offline teaching of a weld line divided into a plurality of segments by steps, the offline teaching method comprising the steps of:

obtaining, by a computer, a position of a current step of a torch of the welding robot and positions of next and previous steps in order to allow the torch of the welding robot to move along a previous segment or a next segment;

setting, by the computer, a previous stage coordinate system ranging from the previous step to the current step and a next stage coordinate system ranging from the current step to the next step by using, if the segment of the weld line is a straight line, an XYZ coordinate system in which a direction of the weld line is a Y direction and a direction perpendicular to a surface of a base material to be welded is a Z direction or, if the segment of the weld line is an arc, an XCZ coordinate system in which a radial direction of the arc is an X direction, a circumferential direction of the arc is a C direction, and a direction perpendicular to a base material to be welded is a Z direction;

inputting, by an operator, an amount of travel in the set coordinate system;

displaying, by the computer using a coordinate system selected by an instruction from the operator, the torch of the welding robot such that the torch is moved along the weld line in the next stage coordinate system or the previous stage coordinate system by the amount of travel;

selecting, before the step of obtaining, axes of a slider and a positioner on which peripheral coordination is to be performed;

inputting, by the operator, either absence of peripheral axis coordination in the step of inputting the amount of travel or presence of peripheral axis coordination in the step of inputting the amount of travel, and either the attitude of the torch is to be fixed or the attitude of the torch is not to be fixed; and

moving, if the peripheral axis coordination is to be performed, at least either the slider or the positioner by an amount proportional to the amount of travel of the torch in relation to the position of the next step,

wherein, if the torch is to be fixed, an angle of the torch is kept the same relative to a positioner setting surface in the coordinate system by setting an angle obtained by subtracting an amount of rotation of the positioner as the angle of the torch, and, if the torch is not to be fixed, the angle of the torch is not changed in the coordinate system.

5. The offline teaching method according to claim 4, further comprising the step of:

changing, by the operator, an angle of the torch in the previous stage coordinate system or the next stage coordinate system.