A novel position control strategy for flexible robot arms based on wave propagation and absorption techniques is presented. The arm is modeled by a lumped-parameter mass-spring system with an actuator at one end and a load mass at the other. The actuator is required to position the remote load and, simultaneously, to provide active vibration damping. It does so by propagating mechanical waves through the system and absorbing reflected waves. Only the first two masses and springs need to be characterized and observed to determine the required actuator movement. The control algorithm is robust and compares very favorably with the time-optimal performance of bang-bang control. It is also inherently adaptive.

Issue Section:
Technical Papers
Topics:
Position control, Robots, Waves, Actuators, Springs, Stress, Absorption, Control algorithms, Damping, Vibration, Wave propagation
1.
Abduljabbar
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,
ElMadany
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,
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Controller Design of a One-link Flexible Robot Arm
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2.
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Book
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,
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Controlled Motion in an Elastic World
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4.
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5.
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V. V.
,
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Y. H.
,
1989
, “
Controller Design Robust to Frequency Variation in a One-link Flexible Robot Arm
,”
ASME JOURNAL OF DYNAMIC SYSTEMS, MEASUREMENT, AND CONTROL
, Vol.
111
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6.
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Mace
B. R.
,
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, “
Active Control of Flexural Vibrations
,”
Journal of Sound and Vibration
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253
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270
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9.
Meckl
P.
, and
Seering
W.
,
1985
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Active Damping in a Three-Axis Robotic Manipulator
,”
ASME Journal of Vibration, Acoustics, Stress, and Reliability in Design
, Vol.
107
, Jan. pp.
38
–
46
.
10.
Meckl
P.
, and
Seering
W.
,
1985
, “
Minimizing Residual Vibration for Point-to-Point Motion
,”
ASME Journal of Vibration, Acoustics, Stress, and Reliability in Design
, Vol.
107
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378
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382
.
11.
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12.
Vincent
T. L.
,
Joshi
S. P.
, and
Lin
Yeong Ching
,
1989
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Positioning and Active Damping of Spring-Mass Systems
,”
ASME JOURNAL OF DYNAMIC SYSTEMS, MEASUREMENT, AND CONTROL
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592
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599
.
13.
Yamada
I.
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Nakagawa
M.
,
1985
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Reduction of Residual Vibration in Position Control Mechanisms
,”
ASME Journal of Vibration, Acoustics, Stress, and Reliability in Design
, Vol.
107
, Jan., pp.
47
–
52
.
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