Spring constant correction device, method therefor, and recording medium
A spring constant correction device and method measure a position and attitude of a distal end of an articulated robot when the articulated robot is operated in a state where elastic deformation is compensated, compare measurement values of the position and attitude of the distal end and target values of the position and attitude, and correct a spring constant based on a result of the comparison. In case of the correction, the spring constant is corrected at a predetermined position based on at least three of: an angle of an end point attitude based on the measured attitude; a torque of the distal end in the end point attitude; an angle of the distal end in a target attitude; and a torque of the distal end in the target attitude. A program of such a method is recorded in a recording medium.
1 . A spring constant correction device applied to an articulated robot in which a speed reducer acts as a spring element and elastically deforms, the articulated robot being operated in a state where elastic deformation is compensated based on a spring constant of the spring element by an elastic deformation compensation unit included in a robot controller,
the spring constant correction device comprising:
a measurement unit that measures a position and attitude of a distal end of the articulated robot when the articulated robot is operated in a state where the elastic deformation is compensated;
a comparison unit that compares measurement values of the position and attitude, of the distal end of the articulated robot, measured by the measurement unit and target values of the position and attitude of the distal end of the articulated robot; and
a correction unit that corrects the spring constant, based on a result obtained by comparison by the comparison unit,
wherein the correction unit corrects, at a predetermined position, the spring constant based on at least three of: an angle of an end point attitude based on the attitude, of the distal end of the articulated robot, measured by the measurement unit; a torque of the distal end of the articulated robot in the end point attitude; an angle of the distal end of the articulated robot in a target attitude; and a torque of the distal end of the articulated robot in the target attitude,
the predetermined position is an end point position of a weaving motion, and
the spring constant is expressed, at the predetermined position, by a functional expression using the torque τ 1 of the distal end of the articulated robot in the end point attitude, the angle θ d of the distal end of the articulated robot in a target attitude, and the torque τ d of the distal end of the articulated robot in the target attitude, the functional expression being:
K
new
=
τ
l
(
θ
l
-
θ
d
)
+
τ
d
K
old
=
τ
l
d
θ
d
+
τ
d
K
old
where K new denotes a corrected spring constant, K old denotes a current spring constant, and dθ d denotes an angular error.
2 . The spring constant correction device according to claim 1 , wherein
the correction unit corrects the spring constant using a least-squares method with respect to the functional expression.
3 . A spring constant correction device applied to an articulated robot in which a speed reducer acts as a spring element and elastically deforms, the articulated robot being operated in a state where elastic deformation is compensated based on a spring constant of the spring element by an elastic deformation compensation unit included in a robot controller, the spring constant correction device comprising:
a measurement unit that measures a position and attitude of a distal end of the articulated robot when the articulated robot is operated in a state where the elastic deformation is compensated;
a comparison unit that compares measurement values of the position and attitude, of the distal end of the articulated robot, measured by the measurement unit and target values of the position and attitude of the distal end of the articulated robot; and
a correction unit that corrects the spring constant, based on a result obtained by comparison by the comparison unit,
wherein the correction unit corrects, at a predetermined position, the spring constant based on at least three of: an angle of an end point attitude based on the attitude, of the distal end of the articulated robot, measured by the measurement unit; a torque of the distal end of the articulated robot in the end point attitude; an angle of the distal end of the articulated robot in a target attitude; and a torque of the distal end of the articulated robot in the target attitude,
the predetermined position is an end point position of a weaving motion, and
the spring constant is expressed, at the predetermined position, by a functional expression using the angle θ 1 of the end point attitude based on the attitude, of the distal end of the articulated robot, measured by the measurement unit, the angle θ d of the distal end of the articulated robot in the target attitude, and the torque τ d of the distal end of the articulated robot in the target attitude, the functional expression being:
K
new
=
1
d
θ
d
τ
d
+
1
K
old
θ
l
θ
d
where K new denotes a corrected spring constant, K old denotes a current spring constant, and dθ d denotes an angular error.
4 . A spring constant correction device applied to an articulated robot in which a speed reducer acts as a spring element and elastically deforms, the articulated robot being operated in a state where elastic deformation is compensated based on a spring constant of the spring element by an elastic deformation compensation unit included in a robot controller, the spring constant correction device comprising:
a measurement unit that measures a position and attitude of a distal end of the articulated robot when the articulated robot is operated in a state where the elastic deformation is compensated;
a comparison unit that compares measurement values of the position and attitude, of the distal end of the articulated robot, measured by the measurement unit and target values of the position and attitude of the distal end of the articulated robot; and
a correction unit that corrects the spring constant, based on a result obtained by comparison by the comparison unit,
wherein the correction unit corrects, at a predetermined position, the spring constant based on at least three of: an angle of an end point attitude based on the attitude, of the distal end of the articulated robot, measured by the measurement unit; a torque of the distal end of the articulated robot in the end point attitude; an angle of the distal end of the articulated robot in a target attitude; and a torque of the distal end of the articulated robot in the target attitude,
the predetermined position is an end point position of a weaving motion, and
the spring constant is expressed, at the predetermined position, by a functional expression using the angle θ 1 of the end point attitude based on the attitude, of the distal end of the articulated robot, measured by the measurement unit, the torque τ 1 of the distal end of the articulated robot in the end point attitude, and the angle θ d of the distal end of the articulated robot in the target attitude, the functional expression being:
K
new
=
1
d
θ
d
τ
d
+
1
K
old
θ
d
θ
l
where K new denotes a corrected spring constant, K old denotes a current spring constant, and dθ d denotes an angular error.
5 . A spring constant correction method applied to an articulated robot in which a speed reducer acts as a spring element and elastically deforms, the articulated robot being operated in a state where elastic deformation is compensated based on a spring constant of the spring element by an elastic deformation compensation unit included in a robot controller,
the spring constant correction method comprising:
a measuring step of measuring a position and attitude of a distal end of the articulated robot when the articulated robot is operated in a state where the elastic deformation is compensated;
a comparing step of comparing measurement values of the position and attitude, of the distal end of the articulated robot, measured in the measuring step and target values of the position and attitude of the distal end of the articulated robot; and
a correcting step of correcting the spring constant, based on a result obtained by comparison in the comparing step,
wherein in the correcting step, the spring constant is corrected, at a predetermined position, based on at least three of: an angle of an end point attitude based on the attitude, of the distal end of the articulated robot, measured in the measuring step; a torque of the distal end of the articulated robot in the end point attitude; an angle of the distal end of the articulated robot in a target attitude; and a torque of the distal end of the articulated robot in the target attitude,
the predetermined position is an end point position of a weaving motion, and
the spring constant is expressed, at the predetermined position, by a functional expression using the torque τy of the distal end of the articulated robot in the end point attitude, the angle θ d of the distal end of the articulated robot in a target attitude, and the torque τ d of the distal end of the articulated robot in the target attitude, the functional expression being:
K
new
=
τ
l
(
θ
l
-
θ
d
)
+
τ
d
K
old
=
τ
l
d
θ
d
+
τ
d
K
old
where K new denotes a corrected spring constant, K old denotes a current spring constant, and dθ d denotes an angular error.
6 . A non-transitory computer-readable medium storing computer readable instructions thereon that are applied to an articulated robot in which a speed reducer acts as a spring element and elastically deforms, the articulated robot being operated in a state where elastic deformation is compensated based on a spring constant of the spring element by an elastic deformation compensation unit included in a robot controller,
the computer readable instructions, when executed by a computer, cause the computer to perform a method comprising:
a measuring step of measuring a position and attitude of a distal end of the articulated robot when the articulated robot is operated in a state where the elastic deformation is compensated;
a comparing step of comparing measurement values of the position and attitude, of the distal end of the articulated robot, measured in the measuring step and target values of the position and attitude of the distal end of the articulated robot; and
a correcting step of correcting the spring constant, based on a result obtained by comparison in the comparing step,
wherein in the correcting step, the spring constant is corrected, at a predetermined position, based on at least three of: an angle of an end point attitude based on the attitude, of the distal end of the articulated robot, measured in the measuring step; a torque of the distal end of the articulated robot in the end point attitude; an angle of the distal end of the articulated robot in a target attitude; and a torque of the distal end of the articulated robot in the target attitude,
the predetermined position is an end point position of a weaving motion, and
the spring constant is expressed, at the predetermined position, by a functional expression using the torque τ 1 of the distal end of the articulated robot in the end point attitude, the angle θ d of the distal end of the articulated robot in a target attitude, and the torque τ d of the distal end of the articulated robot in the target attitude, the functional expression being:
K
new
=
τ
l
(
θ
l
-
θ
d
)
+
τ
d
K
old
=
τ
l
d
θ
d
+
τ
d
K
old
where K new denotes a corrected spring constant, K old denotes a current spring constant, and dθ d denotes an angular error.
7 . The spring constant correction device according to claim 3 , wherein
the correction unit corrects the spring constant using a least-squares method with respect to the functional expression.
8 . The spring constant correction device according to claim 4 , wherein
the correction unit corrects the spring constant using a least-squares method with respect to the functional expression.
9 . A spring constant correction method applied to an articulated robot in which a speed reducer acts as a spring element and elastically deforms, the articulated robot being operated in a state where elastic deformation is compensated based on a spring constant of the spring element by an elastic deformation compensation unit included in a robot controller,
the spring constant correction method comprising:
a measuring step of measuring a position and attitude of a distal end of the articulated robot when the articulated robot is operated in a state where the elastic deformation is compensated;
a comparing step of comparing measurement values of the position and attitude, of the distal end of the articulated robot, measured in the measuring step and target values of the position and attitude of the distal end of the articulated robot; and
a correcting step of correcting the spring constant, based on a result obtained by comparison in the comparing step,
wherein in the correcting step, the spring constant is corrected, at a predetermined position, based on at least three of: an angle of an end point attitude based on the attitude, of the distal end of the articulated robot, measured in the measuring step; a torque of the distal end of the articulated robot in the end point attitude; an angle of the distal end of the articulated robot in a target attitude; and a torque of the distal end of the articulated robot in the target attitude,
the predetermined position is an end point position of a weaving motion, and
the spring constant is expressed, at the predetermined position, by a functional expression using the angle θ 1 of the end point attitude based on the attitude, of the distal end of the articulated robot, measured in the measuring step, the angle θ d of the distal end of the articulated robot in the target attitude, and the torque τ d of the distal end of the articulated robot in the target attitude, the functional expression being:
K
new
=
1
d
θ
d
τ
d
+
1
K
old
θ
l
θ
d
where K new denotes a corrected spring constant, K old denotes a current spring constant, and dθ d denotes an angular error.
10 . A non-transitory computer-readable medium storing computer readable instructions thereon that are applied to an articulated robot in which a speed reducer acts as a spring element and elastically deforms, the articulated robot being operated in a state where elastic deformation is compensated based on a spring constant of the spring element by an elastic deformation compensation unit included in a robot controller,
the computer readable instructions, when executed by a computer, cause the computer to perform a method comprising:
a measuring step of measuring a position and attitude of a distal end of the articulated robot when the articulated robot is operated in a state where the elastic deformation is compensated;
a comparing step of comparing measurement values of the position and attitude, of the distal end of the articulated robot, measured in the measuring step and target values of the position and attitude of the distal end of the articulated robot; and
a correcting step of correcting the spring constant, based on a result obtained by comparison in the comparing step,
wherein in the correcting step, the spring constant is corrected, at a predetermined position, based on at least three of: an angle of an end point attitude based on the attitude, of the distal end of the articulated robot, measured in the measuring step; a torque of the distal end of the articulated robot in the end point attitude; an angle of the distal end of the articulated robot in a target attitude; and a torque of the distal end of the articulated robot in the target attitude,
the predetermined position is an end point position of a weaving motion, and
the spring constant is expressed, at the predetermined position, by a functional expression using the angle θ 1 of the end point attitude based on the attitude, of the distal end of the articulated robot, measured in the measuring step, the angle θ d of the distal end of the articulated robot in the target attitude, and the torque τ d of the distal end of the articulated robot in the target attitude, the functional expression being:
K
new
=
1
d
θ
d
τ
d
+
1
K
old
θ
l
θ
d
where K new denotes a corrected spring constant, K old denotes a current spring constant, and dθ d denotes an angular error.
11 . A spring constant correction method applied to an articulated robot in which a speed reducer acts as a spring element and elastically deforms, the articulated robot being operated in a state where elastic deformation is compensated based on a spring constant of the spring element by an elastic deformation compensation unit included in a robot controller,
the spring constant correction method comprising:
a measuring step of measuring a position and attitude of a distal end of the articulated robot when the articulated robot is operated in a state where the elastic deformation is compensated;
a comparing step of comparing measurement values of the position and attitude, of the distal end of the articulated robot, measured in the measuring step and target values of the position and attitude of the distal end of the articulated robot; and
a correcting step of correcting the spring constant, based on a result obtained by comparison in the comparing step,
wherein in the correcting step, the spring constant is corrected, at a predetermined position, based on at least three of: an angle of an end point attitude based on the attitude, of the distal end of the articulated robot, measured in the measuring step; a torque of the distal end of the articulated robot in the end point attitude; an angle of the distal end of the articulated robot in a target attitude; and a torque of the distal end of the articulated robot in the target attitude,
the predetermined position is an end point position of a weaving motion, and
the spring constant is expressed, at the predetermined position, by a functional expression using the angle θ 1 of the end point attitude based on the attitude, of the distal end of the articulated robot, measured in the measuring step, the torque τi of the distal end of the articulated robot in the end point attitude, and the angle θ d of the distal end of the articulated robot in the target attitude, the functional expression being:
K
new
=
1
d
θ
d
τ
d
+
1
K
old
θ
d
θ
l
where K new denotes a corrected spring constant, K old denotes a current spring constant, and dθ d denotes an angular error.
12 . A non-transitory computer-readable medium storing computer readable instructions thereon that are applied to an articulated robot in which a speed reducer acts as a spring element and elastically deforms, the articulated robot being operated in a state where elastic deformation is compensated based on a spring constant of the spring element by an elastic deformation compensation unit included in a robot controller,
the computer readable instructions, when executed by a computer, cause the computer to perform a method comprising:
a measuring step of measuring a position and attitude of a distal end of the articulated robot when the articulated robot is operated in a state where the elastic deformation is compensated;
a comparing step of comparing measurement values of the position and attitude, of the distal end of the articulated robot, measured in the measuring step and target values of the position and attitude of the distal end of the articulated robot; and
a correcting step of correcting the spring constant, based on a result obtained by comparison in the comparing step,
wherein in the correcting step, the spring constant is corrected, at a predetermined position, based on at least three of: an angle of an end point attitude based on the attitude, of the distal end of the articulated robot, measured in the measuring step; a torque of the distal end of the articulated robot in the end point attitude; an angle of the distal end of the articulated robot in a target attitude; and a torque of the distal end of the articulated robot in the target attitude,
the predetermined position is an end point position of a weaving motion, and
the spring constant is expressed, at the predetermined position, by a functional expression using the angle θ 1 of the end point attitude based on the attitude, of the distal end of the articulated robot, measured in the measuring step, the torque τi of the distal end of the articulated robot in the end point attitude, and the angle θ d of the distal end of the articulated robot in the target attitude, the functional expression being:
K
new
=
1
d
θ
d
τ
d
+
1
K
old
θ
d
θ
l
where K new denotes a corrected spring constant, K old denotes a current spring constant, and dθ d denotes an angular error.