Control device, control method, and control program for articulated robot

Patent metadata

Field	Value
Publication number	US-9242373-B2
Application number	US-201214003429-A
Country	US
Kind code	B2
Filing date	Mar 2, 2012
Priority date	Mar 8, 2011
Publication date	Jan 26, 2016
Grant date	Jan 26, 2016

Abstract

The purpose of the present invention is to have the angles of each of the drive shafts of the first articulated drive system infallibly reach the angle of the work completed position, while maintaining the rate of movement and position of the working parts of an articulated robot. If exception conditions are not satisfied, the drive shafts of first and second articulation drive systems are driven individually (S 64 ) on the basis of interpolated points calculated in step 5 (S 5 ). After exception conditions are satisfied (Yes side of S 61 ), until the working parts reach the work completed position (No side of S 12 ), the angle of each of the drive shafts of the first articulated drive system required to vary each of the drive shafts of the first articulated drive system in a linear manner with the angle at the work completed position as a target is calculated (S 8 ), and the angle of each of the drive shafts of the second articulated drive system is calculated on the basis of the position of the working part at the interpolated point calculated in step 5 (S 5 ) and the angle of each of the drive shafts of the first articulated drive system as calculated (S 9 ), and the drive shafts of the first and second articulated drive systems are driven according to said calculation results (S 11 ).

First claim

The invention claimed is:

1. An articulated robot control device for controlling an articulated robot including a first articulated drive system, which includes three drive shafts for changing an attitude of a working part disposed at a forward end, and a second articulated drive system, which includes at least three drive shafts for changing a position of the first articulated drive system, the control device comprising:
an interpolation point calculator for calculating a plurality of interpolation points to move a position of the working part at a predetermined speed on a teaching path interconnecting respective positions and attitudes at a work start point and a work end point, which are set in advance;
a driving controller for driving the first articulated drive system and the second articulated drive system in accordance with the interpolation points calculated by the interpolation point calculator;
an exception condition determiner for determining whether or not a preset exception condition, which is different from a condition for detecting a singular attitude of the first articulated drive system, is satisfied when the first articulated drive system and the second articulated drive system are driven by the driving controller; and
an exceptional operator for, after the exception condition determiner determines that the exception condition is satisfied, calculating respective angles of the drive shafts of the first articulated drive system, the angles being adapted to linearly change the drive shafts of the first articulated drive system with angles to be taken at the work end point being targets, until the working part reaches the work end point, calculating respective angles of the drive shafts of the second articulated drive system based on the respective calculated angles of the drive shafts of the first articulated drive system and on the position of the working part at a next interpolation point calculated by the interpolation point calculator, and driving the respective drive shafts of the first articulated drive system and the second articulated drive system based on calculation results;
wherein the exception condition is given as a condition that a speed of at least one of the drive shafts of the first articulated drive system, which is defined by a remaining moving time or a remaining moving distance from a next interpolation point to the work end point, exceeds a preset allowable range when the respective angles of the drive shafts of the first articulated drive system are made to reach the angles to be taken at the work end point in the remaining moving time or the remaining moving distance of the working part from the next interpolation point.

2. The articulated robot control device according to claim 1 , further comprising a deviation amount detector for detecting a deviation amount between the working part and a work line of a workpiece, a copying controller for moving the working part to trace the work line based on the deviation amount detected by the deviation amount detector, and a work end point updater for updating the work end point by adding the deviation amount, which is detected by the deviation amount detector, to the work end point,
wherein the exception condition determiner and/or the exceptional operator executes processing based on the work end point after being updated by the work end point updater.

3. The articulated robot control device according claim 1 , wherein the exceptional operator comprises:
an angle candidate calculator for calculating a plurality of angle candidates for each of the drive shafts within a range of angle closer to the target than when each of the drive shafts of the first articulated drive system is linearly operated with the angle to be taken at the work end point being the target; and
an angle selector for selecting, from the angle candidates calculated by the angle candidate calculator, one candidate at which variations of preset one or two particular angles among three attitude angles in a work coordinate system, as viewed from the working part, at a next interpolation point are most suppressed, when the angle candidates are each separately employed.

4. A control method for an articulated robot for controlling an articulated robot including a first articulated drive system, which includes three drive shafts for changing an attitude of a working part disposed at a forward end, and a second articulated drive system, which includes at least three drive shafts for changing a position of the first articulated drive system, the control method comprising:
an interpolation point calculating step of calculating a plurality of interpolation points to move a position of the working part at a predetermined speed on a teaching path interconnecting respective positions and attitudes at a work start point and a work end point, which are set in advance;
a driving control step of driving the first articulated drive system and the second articulated drive system in accordance with the interpolation points calculated in the interpolation point calculating step;
an exception condition determining step of determining whether or not a preset exception condition, which is different from a condition for detecting a singular attitude of the first articulated drive system, is satisfied when the first articulated drive system and the second articulated drive system are driven in the driving control step; and
an exceptional operation step of, after the exception condition determining step determines that the exception condition is satisfied, calculating respective angles of the drive shafts of the first articulated drive system, the angles being adapted to linearly change the drive shafts of the first articulated drive system with angles to be taken at the work end point being targets, until the working part reaches the work end point, calculating respective angles of the drive shafts of the second articulated drive system based on the respective calculated angles of the drive shafts of the first articulated drive system and on the position of the working part at a next interpolation point calculated in the interpolation point calculating step, and driving the respective drive shafts of the first articulated drive system and the second articulated drive system based on calculation results;
wherein the exception condition is given as a condition that a speed of at least one of the drive shafts of the first articulated drive system, which is defined by a remaining moving time or a remaining moving distance from a next interpolation point to the work end point, exceeds a preset allowable range when the respective angles of the drive shafts of the first articulated drive system are made to reach the angles to be taken at the work end point in the remaining moving time or the remaining moving distance of the working part from the next interpolation point.

5. A control program for an articulated robot for controlling an articulated robot including a first articulated drive system, which includes three drive shafts for changing an attitude of a working part disposed at a forward end, and a second articulated drive system, which includes at least three drive shafts for changing a position of the first articulated drive system, the program causing a processor to execute:
an interpolation point calculating step of calculating a plurality of interpolation points to move a position of the working part at a predetermined speed on a teaching path interconnecting respective positions and attitudes at a work start point and a work end point, which are set in advance;
a driving control step of driving the first articulated drive system and the second articulated drive system in accordance with the interpolation points calculated in the interpolation point calculating step;
an exception condition det

Assignees

• One Tsutomu
• Nishimura Toshihiko
• Shigeyoshi Masayuki
• Koike Takeshi
• Kobe Steel Ltd

Inventors

• One Tsutomu
• Nishimura Toshihiko
• Shigeyoshi Masayuki
• Koike Takeshi

Classifications

• B23K9/095 Primary

  Monitoring or automatic control of welding parameters · CPC title

• B25J9/1664

  characterised by motion, path, trajectory planning · CPC title

• G05B2219/42207

  Generate points between start and end position, linear interpolation · CPC title

• G05B19/4103

  Digital interpolation · CPC title

• B25J9/1628 Primary

  characterised by the control loop · CPC title