Abstract

Under-actuated robots are very interesting in terms of cost and weight since they can result in a state-controllable system with a number of actuators lower than the number of joints. In this paper, a comparison between an under-actuated planar three-degrees-of-freedom (DOF) robot and a comparable fully actuated two-degrees-of-freedom robot is presented, mainly focusing on the performances in terms of trajectories, actuator torques, and vibrations. The under-actuated system is composed of two active rotational joints followed by a passive rotational joint equipped with a torsional spring. The fully actuated robot is inertial equivalent to the under-actuated manipulator: the last link is equal to the sum of the last two links of the under-actuated system. Due to the conditions on the inertia distribution and spring placement, in a simple point-to-point movement the last passive joint starts and ends in a zero-value configuration, so the three DOF robot is equivalent, in terms of initial and final configuration, to the two DOF fully actuated robot, thus they can be compared. Results show how while the fully actuated robot is better in terms of reliable trajectory and actuator torques, the under-actuated robot wins in flexibility and in vibrations at a given configuration.

References

1.
Barbazza
,
L.
,
Oscari
,
F.
,
Minto
,
S.
, and
Rosati
,
G.
,
2017
, “
Trajectory Planning of a Suspended Cable Driven Parallel Robot With Reconfigurable End Effector
,”
Rob. Comput.-Integr. Manuf.
,
48
(
1
), pp.
1
11
.
2.
Fliess
,
M.
,
Lévine
,
J.
,
Martin
,
P.
, and
Rouchon
,
P.
,
1995
, “
Flatness and Defect of Non-linear Systems: Introductory Theory and Examples
,”
Int. J. Control.
,
61
(
6
), pp.
1327
1361
.
3.
Sira-Ramirez
,
H.
, and
Agrawal
,
S. K.
,
2004
,
Differentially Flat Systems
,
CRC Press
,
Boca Raton, FL
.
4.
Agrawal
,
S. K.
, and
Sangwan
,
V.
,
2006
, “
Design of Under-Actuated Open-Chain Planar Robots for Repetitive Cyclic Motions
,”
ASME 2006 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference
,
Philadelphia, PA
,
Sept. 10–13
, American Society of Mechanical Engineers, pp.
1057
1066
.
5.
Franch
,
J.
,
Agrawal
,
S. K.
, and
Sangwan
,
V.
,
2010
, “
Differential Flatness of a Class of n-DOF Planar Manipulators Driven by 1 Or 2 Actuators
,”
IEEE. Trans. Automat. Contr.
,
55
(
2
), pp.
548
554
.
6.
Franch
,
J.
,
Reyes
,
A.
, and
Agrawal
,
S. K.
,
2013
, “
Differential Flatness of a Class of N–DOF Planar Manipulators Driven by An Arbitrary Number of Actuators
,”
2013 European Control Conference (ECC)
,
Zurich, Switzerland
,
July 17–19
, IEEE, pp.
161
166
.
7.
He
,
B.
,
Wang
,
S.
, and
Liu
,
Y.
,
2019
, “
Underactuated Robotics: A Review
,”
Int. J. Adv. Rob. Syst.
,
16
(
4
), p.
1729881419862164
.
8.
Huang
,
A.-C.
,
Chen
,
Y.-F.
, and
Kai
,
C.-Y.
,
2015
,
Adaptive Control of Underactuated Mechanical Systems
,
World Scientific
,
Toh Tuck Link
.
9.
Mareczek
,
J.
,
Buss
,
M.
, and
Schmidt
,
G.
,
1998
, “
Robust Global Stabilization of the Underactuated 2-DOF Manipulator R2D1
,”
Proceedings of the 1998 IEEE International Conference on Robotics and Automation (Cat. No. 98CH36146), Vol. 3
,
Leuven, Belgium
, IEEE, pp.
2640
2645
.
10.
Mareczek
,
J.
,
Buss
,
M.
, and
Schmidt
,
G.
,
1999
, “
Robust Control of a Non-Holonomic Underactuated Scara Robot
,”
Progress in System and Robot Analysis and Control Design
,
Springer
, pp.
381
396
.
11.
Mottard
,
A.
,
Laliberté
,
T.
, and
Gosselin
,
C.
,
2017
, “
Underactuated Tendon-Driven Robotic/Prosthetic Hands: Design Issues.
Robotics: Science and Systems.
,
Cambridge, MA
.
12.
Teng
,
Z.
,
Xu
,
G.
,
Liang
,
R.
,
Li
,
M.
,
Zhang
,
S.
,
Chen
,
J.
, and
Han
,
C.
,
2018
, “
Design of An Underactuated Prosthetic Hand With Flexible Multi-Joint Fingers and Eeg-Based Control
,”
2018 IEEE International Conference on Cyborg and Bionic Systems (CBS)
,
Shenzhen, China
,
Oct. 25–27
, IEEE, pp.
647
651
.
13.
Abdolshah
,
S.
,
Zanotto
,
D.
,
Rosati
,
G.
, and
Agrawal
,
S. K.
,
2017
, “
Optimizing Stiffness and Dexterity of Planar Adaptive Cable-Driven Parallel Robots
,”
ASME J. Mech. Rob.
,
9
(
3
), p.
031004
.
14.
Aguilar-lbÅAñez
,
C.
, and
Sira-Ramirez
,
H.
,
2002
, “
PD Control for Active Vibration Damping in An Underactuated Nonlinear System
,”
Asian J. Control
,
4
(
4
), pp.
502
508
.
15.
Bergerman
,
M.
,
Xu
,
Y.
, and
Liu
,
Y.-H.
,
1998
, “
Control of Cooperative Underactuated Manipulators: A Robustness Comparison Study
,”
1st Workshop on Robotics and Mechatronics
,
Hong Kong
, Citeseer, pp.
279
286
.
16.
Nudehi
,
S. S.
, and
Mukherjee
,
R.
,
2004
, “
Enhancing Controllability and Observability in Underactuated and Undersensed Systems Through Switching: Application to Vibration Control
,”
ASME J. Dyn. Syst. Meas. Control.
,
126
(
4
), pp.
790
799
.
17.
Siqueira
,
A. A.
, and
Terra
,
M. H.
,
2004
, “
Nonlinear and Markovian H/sub/spl Infin//controls of Underactuated Manipulators
,”
IEEE Trans. Control Syst. Technol.
,
12
(
6
), pp.
811
826
.
18.
Boscariol
,
P.
, and
Richiedei
,
D.
,
2018
, “
Robust Point-to-Point Trajectory Planning for Nonlinear Underactuated Systems: Theory and Experimental Assessment
,”
Rob. Comput.-Integr. Manuf.
,
50
(
5
), pp.
256
265
.
19.
Agrawal
,
S.
,
Pathak
,
K.
,
Franch
,
J.
,
Lampariello
,
R.
, and
Hirzinger
,
G.
,
2009
, “
A Differentially Flat Open-Chain Space Robot with Arbitrarily Oriented Joint Axes and Two Momentum Wheels At the Base
,”
IEEE. Trans. Automat. Contr.
,
54
(
9
), pp.
2185
2191
.
20.
Siciliano
,
B.
,
Sciavicco
,
L.
,
Villani
,
L.
, and
Oriolo
,
G.
,
2010
,
Robotics: Modelling, Planning and Control
,
Springer Science & Business Media
,
London
.
21.
Agrawal
,
S. K.
, and
Sangwan
,
V.
,
2008
, “
Differentially Flat Designs of Underactuated Open-Chain Planar Robots
,”
IEEE Trans. Rob.
,
24
(
6
), pp.
1445
1451
.
22.
Zanotto
,
D.
,
Rosati
,
G.
, and
Agrawal
,
S. K.
,
2011
, “
Modeling and Control of a 3-DOF Pendulum-Like Manipulator
,”
2011 IEEE International Conference on Robotics and Automation
,
Shanghai, China
,
May 9–13
, IEEE, pp.
3964
3969
.
23.
Barbazza
,
L.
,
Zanotto
,
D.
,
Rosati
,
G.
, and
Agrawal
,
S. K.
,
2017
, “
Design and Optimal Control of An Underactuated Cable-Driven Micro-Macro Robot
,”
IEEE Rob. Autom. Lett.
,
2
(
2
), pp.
896
903
.
24.
Bottin
,
M.
,
Cocuzza
,
S.
,
Comand
,
N.
, and
Doria
,
A.
,
2020
, “
Modeling and Identification of An Industrial Robot With a Selective Modal Approach
,”
Appl. Sci.
,
10
(
13
), p.
4619
.
25.
Zhang
,
H.
,
Wang
,
J.
,
Zhang
,
G.
,
Gan
,
Z.
,
Pan
,
Z.
,
Cui
,
H.
, and
Zhu
,
Z.
,
2005
, “
Machining with Flexible Manipulator: Toward Improving Robotic Machining Performance
,”
Proceedings of the 2005 IEEE/ASME International Conference on Advanced Intelligent Mechatronics
,
Monterey, CA
,
July 24–28
, IEEE, pp.
1127
1132
.
26.
Inman
,
D. J.
, and
Singh
,
R. C.
,
1994
,
Engineering Vibration
, Vol.
3
,
Prentice Hall Englewood Cliffs
,
NJ
.
27.
Doria
,
A.
,
Cocuzza
,
S.
,
Comand
,
N.
,
Bottin
,
M.
, and
Rossi
,
A.
,
2019
, “
Analysis of the Compliance Properties of An Industrial Robot with the Mozzi Axis Approach
,”
Robotics
,
8
(
3
), p.
80
.
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