The energy balancing concept seeks to reduce actuation requirements for a morphing structure by strategically locating negative stiffness devices to tailor the required deployment forces and moments. One such device is the spiral pulley negative stiffness mechanism. This uses a cable connected with a pre-tension spring to convert the decreasing spring force into the increasing balanced torque. The kinematics of the spiral pulley is first developed for bidirectional actuation, and its geometry is then optimized by employing an energy conversion efficiency function. The performance of the optimized bidirectional spiral pulley is then evaluated through the net torque, the total required energy, and energy conversion efficiency. Then, an additional test rig tests the bidirectional negative stiffness property and compares the characteristics with the corresponding analytical result. Exploiting the negative stiffness mechanism is of significant interest not only in the field of morphing aircraft but also in many other energy and power reduction applications.

References

References
1.
Karnopp
,
D.
,
1995
, “
Active and Semi-Active Vibration Isolation
,”
ASME J. Mech. Des.
,
117
(
B
), pp.
177
185
.
2.
Churchill
,
C. B.
,
Shahan
,
D. W.
,
Smith
,
S. P.
,
Keefe
,
A. C.
, and
McKnight
,
G. P.
,
2016
, “
Dynamically Variable Negative Stiffness Structures
,”
Sci. Adv.
,
2
(
2
), pp.
e1500778
e1500778
.
3.
Chu
,
Y.-L.
, and
Kuo
,
C.-H.
,
2017
, “
A Single-Degree-of-Freedom Self-Regulated Gravity Balancer for Adjustable Payload
,”
ASME J. Mech. Robot
,
9
(
2
), p.
021006
.
4.
Barents
,
R.
,
Schenk
,
M.
,
van Dorsser
,
W. D.
,
Wisse
,
B. M.
, and
Herder
,
J. L.
,
2011
, “
Spring-to-Spring Balancing as Energy-Free Adjustment Method in Gravity Equilibrators
,”
ASME J. Mech. Des.
,
133
(
6
), p.
061010
.
5.
Hoetmer
,
K.
,
Herder
,
J. L.
, and
Kim
,
C. J.
,
2009
, “
A Building Block Approach for the Design of Statically Balanced Compliant Mechanisms
,”
ASME 2009 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference
,
San Diego, CA
,
Aug. 30–Sept. 2
, pp.
313
323
.
6.
Zhang
,
J.
,
Shaw
,
A. D.
,
Mohammadreza
,
A.
,
Friswell
,
M. I.
, and
Woods
,
B. K. S.
,
2018
, “
Spiral Pulley Negative Stiffness Mechanism for Morphing Aircraft Actuation
,”
ASME 2018 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference
,
Quebec, Canada
,
Aug. 26–29
, p.
V05BT07A003
.
7.
Schenk
,
M.
, and
Guest
,
S. D.
,
2014
, “
On Zero Stiffness
,”
Proc. Inst. Mech. Eng. Part C J. Mech. Eng. Sci.
,
228
(
10
),
1701
1714
.
8.
Ostler
,
J.
, and
Zwick
,
K.
,
1939
, “
Power Equalizing Device
,” U.S. Patent No. 2,178,122.
9.
Woods
,
B. K. S.
,
Friswell
,
M. I.
, and
Wereley
,
N. M.
,
2014
, “
Advanced Kinematic Tailoring for Morphing Aircraft Actuation
,”
AIAA J.
,
52
(
4
), pp.
788
798
.
10.
Woods
,
B. K.
, and
Friswell
,
M. I.
,
2016
, “
Spiral Pulley Negative Stiffness Mechanism for Passive Energy Balancing
,”
J. Intell. Mater. Syst. Struct.
,
27
(
12
), pp.
1673
1686
.
11.
Zhang
,
J.
,
Shaw
,
A. D.
,
Amoozgar
,
M.
,
Friswell
,
M. I.
, and
Woods
,
B. K. S.
,
2019
, “
Bidirectional Torsional Negative Stiffness Mechanism for Energy Balancing Systems
,”
Mech. Mach. Theory
,
131
(
2019
), pp.
91
107
.
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