Setting method and setting apparatus for operation path for articulated robot

• US 20040138779A1
• Filed: 08/19/2003
• Published: 07/15/2004
• Est. Priority Date: 02/19/2001
• Status: Active Grant

• Current Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Original Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Inventors: Shibata, Kaoru, Kaneko, Masakatsu, Nakajima, Ryo
• Granted Patent: US 7,110,859 B2
• Time in Patent Office: Days
• US Class Current: 700/245
• CPC Class Codes: B23K 11/11 Spot welding
• CPC Class Codes: B25J 9/1666 Avoiding collision or forbidden zones
• CPC Class Codes: G05B 2219/39094 Interference checking between robot and fixture
• CPC Class Codes: G05B 2219/45104 Lasrobot, welding robot

Abstract

A temporary operation path is set by connecting a plurality of welding points (Tn) in a virtual space generated by a computer to investigate whether an end effector (68) can be operated along the temporary operation path. If the operation cannot be operated, a path to avoid interference with a workpiece (80) is set automatically while extracting a portion in which the workpiece (80) exists in the internal space surrounded by the end effector (68) in order to set a narrow-area operation path for withdrawing the end effector (68) from a welding point (Tn). Next, in order to set a wide-area operation path for making movement between withdrawing points (Ue), a template operation is applied, in which the end effector (68) is moved by a prescribed distance in a prescribed direction.

Claims

1. A method for setting an operation path for an articulated robot (50) including an end effector (68), said method comprising:

an internal space-defining step of defining an internal space which is partially surrounded by an arm (74) or electrodes (70, 72) of said end effector (68);

an extracting step of extracting an objective workpiece portion (1096) of a workpiece (80) to be welded, said objective workpiece portion (1096) existing in said internal space; and

an interference-investigating step of investigating whether interference occurs between said end effector (68) and said objective workpiece portion (1096) when said articulated robot (50) is operated.

2. The method for setting said operation path for said articulated robot (50) according to claim 1, wherein said workpiece (80) is a model which is approximated with a plurality of blocks (1094).

3. The method for setting said operation path for said articulated robot (50) according to claim 1, wherein said internal space is a model which is approximated with a plurality of blocks (1094).

4. The method for setting said operation path for said articulated robot (50) according to claim 1, wherein said interference-investigating step comprises:

a reference line-defining step of defining a reference line (M1) passing through a center of said objective workpiece portion (1096);

an investigation end position-defining step of setting an investigation end position (Ue) for said end effector on said reference line (M1); and

a first detailed interference-investigating step of investigating whether interference occurs between said end effector (68) and said objective workpiece portion (1096) by operating said end effector (68) from an investigation start position (Ts) to said investigation end position (Ue).

5. The method for setting said operation path for said articulated robot (50) according to claim 1, wherein said interference-investigating step comprises:

a reference line-defining step of defining a reference line (M1) passing through a center of said objective workpiece portion (1096);

a center of gravity position-defining step of defining a center of gravity position (G1) of said objective workpiece portion (1096) based on said reference line (M1); and

a second detailed interference-investigating step of investigating whether interference occurs between said end effector (68) and said objective workpiece portion (1096) by operating said end effector (68) from an investigation start position (Ts) to said center of gravity position (G1).

6. The method for setting said operation path for said articulated robot (50) according to claim 5, wherein a portion of said objective workpiece portion (1096), which is located near an opening as compared with said center of gravity position (G1) of said objective workpiece portion (1096), is extracted as a new objective workpiece portion (1096b) to perform said center of gravity position-defining step and said second detailed interference-investigating step, said objective workpiece portion (1096) being replaced with said new objective workpiece portion (1096b).

7. An apparatus for setting an operation path for an articulated robot (50) including an end effector (68), said apparatus comprising:

an internal space-defining section (35d) for defining an internal space which is partially surrounded by an arm (74) or electrodes (70, 72) of said end effector (68);

a workpiece-extracting section (35e) for extracting an objective workpiece portion (1096) to be welded of a workpiece (80), said objective workpiece portion (1096) existing in said internal space; and

an interference-investigating section (40a) for investigating whether interference occurs between said end effector (68) and said objective workpiece portion (1096) when said end effector (68) is operated.

8. A method for setting an operation path for an articulated robot (50) for operating an end effector (68) from a start point (P1, Q1) to an arrival point (P2, Q2), said method comprising:

an operation-investigating step of setting a path (100, 104) for connecting said start point (P1, Q1) and said arrival point (P2, Q2) to investigate whether said end effector (68) can be operated along said path (100, 104); and

a retracting path-setting step of setting a retracting path (102, 110) for operating said end effector (68) by a prescribed distance in a prescribed direction from said start point (P1, Q1) or said arrival point (P2, Q2) if said end effector (68) cannot be operated along said path (100, 104) in said operation-investigating step.

9. The method for setting said operation path for said articulated robot (50) according to claim 8, wherein said prescribed direction is predetermined based on a posture of said end effector (68) at said start point (P1, Q1) or said arrival point (P2, Q2).

10. The method for setting said operation path for said articulated robot (50) according to claim 8, wherein said prescribed direction is a direction to connect said start point (P1, Q1) or said arrival point (P1, Q2) and an established point (106) in space.

11. The method for setting said operation path for said articulated robot (50) according to claim 10, wherein said established point is a central point (0) of an original axis of said articulated robot (50).

12. The method for setting said operation path for said articulated robot (50) according to claim 8, wherein an end point of said retracting path (102, 110) is defined as a new start point or a new arrival point to execute said operation-investigating step or said retracting path-setting step again.

13. The method for setting said operation path for said articulated robot (50) according to claim 8, wherein said retracting path (102, 110) is set again if an end point of said retracting path (102, 110) is a point at which said articulated robot (50) cannot arrive or at which interference occurs, said prescribed distance being corrected in said retracting path (102, 110).

14. An apparatus for setting an operation path for an articulated robot (50) for operating an end effector (68) from a start point (P1, Q1) to an arrival point (P2, Q2), said apparatus comprising:

a path-investigating section (35c) for setting a path (100, 104) for connecting said start point (P1, Q1) and said arrival point (P2, Q2) to investigate whether said end effector (68) can be operated along said path (100, 104); and

a wide-area operation path-setting section (35b) for setting a retracting path for operating said end effector (68) by a prescribed distance in a prescribed direction from said start point (P1, Q1) or said arrival point (P2, Q2) if said path-investigating section (35c) judges that said end effector (68) cannot be operated along said path (100, 104).

15. A method for setting an operation path for an articulated robot (50) for operating an end effector (68) between operation points (Tn) for a workpiece (80), said method comprising:

a narrow-area operation path-setting step of setting a narrow-area operation path for retracting said end effector (68) from said operation point (Tn) to a point located near an end of said workpiece (80) without interfering in said workpiece (80) and another obstacle (82) based on shapes of said obstacle (82) and said workpiece (80) near said operation point (Tn), said end effector (68) being arranged at said operation point for said workpiece (80); and

a wide-area operation path-setting step of setting a wide-area operation path for effecting operation from a start point (P1, Q1) to an arrival point (P2, Q2) by combining predetermined prescribed operations provided that said start point (P1, Q1) and said arrival point (P2, Q2) reside in predetermined points located near said end of said workpiece (80).

16. The method for setting said operation path for said articulated robot (50) according to claim 15, wherein said narrow-area operation path-setting step comprises:

an internal space-defining step of defining an internal space which is partially surrounded by an arm (74) or electrodes (70, 72) of said end effector (68);

an extracting step of extracting an objective workpiece portion (1096) of said workpiece (80), said objective workpiece portion (1096) existing in said internal space; and

an interference-investigating step of investigating whether interference occurs between said end effector (68) and said objective workpiece portion (1096) when said articulated robot (50) is operated.

17. The method for setting said operation path for said articulated robot (50) according to claim 15, wherein said wide-area operation path-setting step comprises:

an operation-investigating step of setting a path (100, 104) for connecting said start point (P1, Q1) and said arrival point (P2, Q2) to investigate whether said end effector (68) can be operated along said path (100, 104); and

a retracting path-setting step of setting a retracting path (102, 110) for operating said end effector (68) by a prescribed distance in a prescribed direction from said start point (P1, Q1) or said arrival point (P2, Q2) if said end effector (68) cannot be operated along said path (100, 104) in said operation-investigating step.

18. The method for setting said operation path for said articulated robot (50) according to claim 17, wherein said prescribed direction is predetermined based on a posture of said end effector (68) at said start point (P1, Q1) or said arrival point (P2, Q2).

19. The method for setting said operation path for said articulated robot (50) according to claim 17, wherein said prescribed direction is a direction to connect said start point (P1, Q1) or said arrival point (P2, Q2) and an established point (106) in space.

20. An apparatus for setting an operation path for an articulated robot (50) for operating an end effector (68) between operation points (Tn) for a workpiece (80), said apparatus comprising:

a narrow-area operation path-setting section (35a) for setting a narrow-area operation path for retracting said end effector (68) from said operation point (Tn) to a point located near an end of said workpiece (80) without interfering in said workpiece (80) and another obstacle (82) based upon shapes of said obstacle (82) and said workpiece (80) near said operation point (Tn), said end effector (68) being arranged at said operation point (Tn) for said workpiece (80); and

a wide-area operation path-setting section (35b) for setting a wide-area operation path for effecting operation from a start point (P1, Q1) to an arrival point (P2, Q2) by combining predetermined prescribed operations provided that said start point (P1, Q1) and said arrival point (P2, Q2) reside in predetermined points located near said end of said workpiece (80).