US011248698B2

( 12 ) United States Patent ( 10) Patent No .: US 11,248,698 B2

Kopp (45 ) Date of Patent : * Feb . 15 , 2022
( 54 ) MULTIPLE ACTUATOR AND LINKAGE ( 56 ) References Cited
SYSTEM
U.S. PATENT DOCUMENTS
( 71 ) Applicant: Moog Inc. , East Aurora , NY (US ) 1,294,970 A 7/1872 Russell
2,652,995 A 9/1953 Swain et al .
( 72 ) Inventor: John Kopp , West Seneca , NY (US) (Continued )
( 73 ) Assignee : Moog Inc. , East Aurora, NY (US ) FOREIGN PATENT DOCUMENTS
(*) Notice: Subject to any disclaim the term of this CN 85103699 A 11/1986
patent is extended or adjusted under 35 CN 1154325 A 7/1997
U.S.C. 154 ( b ) by 126 days . (Continued )
This patent is subject to a terminal dis
claimer . OTHER PUBLICATIONS
( 21 ) Appl. No .: 16 /402,542 Office Action received in corresponding Chinese Application No.
201280072035.5 ( 9 pages ) dated Sep. 2 , 2016 .
(22 ) Filed : May 3 , 2019 (Continued )
( 65 ) Prior Publication Data Primary Examiner Eric C Wai
US 2019/0257419 A1 Aug. 22 , 2019 (74 ) Attorney, Agent, or Firm Harter Secrest & Emery
LLP

(57 ) ABSTRACT
Related U.S. Application Data An actuator system comprising a shared link arranged to
( 63 ) Continuation of application No. 14 /376,000 , filed as pivot about a first axis relative to a reference structure , a
application No. PCT /US2012 /024558 on Feb. 9 , controlled element arranged to pivot about a second axis
2012 , now Pat . No. 10,281,033 . relative to the reference structure, a first member arranged to
pivot about a third axis relative to the shared link and a
( 51 ) Int. Ci. fourth axis relative to the controlled member, a first actuator
F16H 61/28 ( 2006.01 ) arranged to control a first variable distance between the third
B64C 13/28 ( 2006.01 ) axis and fourth axis , a second member arranged to pivot
( Continued ) about a fifth axis relative to the shared link and a sixth axis
( 52) U.S. Cl. relative to the controlled element, a second actuator arranged
to control a second variable distance between the fifth axis
CPC F16H 61/2807 (2013.01 ) ; B64C 13/30 and the sixth axis , the system configured such that a change
(2013.01 ) ; B64C 13/341 ( 2018.01 ) ; G05B in the first variable distance causes rotation of the controlled
15/02 (2013.01 ) element about the second axis when the second variable
( 58 ) Field of Classification Search distance is constant and vice versa .
None
See application file for complete search history. 7 Claims , 15 Drawing Sheets
159 167
120a

130
162 127
164 125
136
L1 ' 146
161
121
152
120b
143 128
126
141
153 dL2
L2 147
135
1634
166 122
129 158
 US 11,248,698 B2
Page 2

( 51 ) Int . Ci. DE
DE
10021324
102010024121
A1
A1
11/2001
12/2011
B64C 13/30 ( 2006.01 ) EP 0382903 A2 8/1990
G05B 15/02 ( 2006.01 ) EP 1721826 A1 11/2006
FR 70758 E 7/1959
( 56 ) References Cited FR 2706966 A 12/1994
FR 2906220 A1 3/2008
U.S. PATENT DOCUMENTS GB 593642 A 10/1947
GB 730561 A 5/1955
2,695,145 A 11/1954 Lear et al . GB 1500404 A 2/1978
2,855,793 A 10/1958 Parker et al . JP S5077044 A 6/1975
3,523,460 A 8/1970 Beauvais JP S61157870 A 7/1986
3,561,784 A 2/1971 Bantle JP HO3113156 A 5/1991
3,612,106 A 10/1971 Indre et al . JP H10141499 A 5/1998
4,225,110 A 9/1980 Akkerman et al. JP 2001271808 A 10/2001
4,228,386 A 10/1980 Griffith JP 2006522295 A 9/2006
7/1985 Barnes JP 2007176486 A 7/2007
4,531,448 A JP 2008137436 A 6/2008
4,555,978 A 12/1985 Burandt et al . WO 1985004459 Al 10/1985
4,605,358 A 8/1986 Burandt et al . WO 2008028184 A2 3/2008
4,685,550 A 8/1987 Metcalf WO 2009020452 Al 2/2009
4,808,955 A 2/1989 Godkin et al . WO 2010078082 Al 7/2010
4,858,491 A 8/1989 Shube
5,120,285 A 6/1992 Grimm
5,152,381 A 10/1992 Appleberry OTHER PUBLICATIONS
5,518,466 A 5/1996 Tiedeman
5,628,234 A 5/199 Crook et al . Recksiek , Advanced High Lift System Architecture with Distributed
5,701,801 A 12/1997 Boehringer et al . Electrical Flap Actuation, AST 2009 , Mar. 29-30 , Hamburg, Ger
5,806,806 A 9/1998 Boehringer et al . many.
5,957,798 A 9/1999 Smith , III et al . Charrier, Electric Actuation for Flight & Engine Control: Evolution
6,189,436 B1 2/2001 Brooks
& Challenges, SAE - ACGSC Mtg 99 , Feb. 28 -Mar. 2 , 2007 Boulder
2004/0080197 A1 4/2004 Kopetzky Meeting
2004/0238688 A1 12/2004 Audren
2006/0138829 Al 6/2006 Kopetzky Wu et al . , Fault - Tolerant Joint Development for the Space Shuttle
2006/0255207 Al 11/2006 Wingett et al . Remote Manipulator System : Analysis and Experiment, Robotics
2007/0018040 A1 1/2007 Wingett et al . and Automation, IEEE Transactions, Oct. 1993 , vol . 9 , Issue 5 ,
2007/0068291 A1 3/2007 Beatty et al . Houston , Texas .
2007/0262194 A1 11/2007 Agrawal et al . Liscouet et al . , Evaluation of Architectures for Electromechanical
2008/0025770 A1 1/2008 Burnett Actuators, 26th International Congress of the Aeronautical Sci
2008/0098942 Al 5/2008 Morse et al . ences, 2008 .
2008/0203223 Al 8/2008 Cyrot et al . The International Search Report of the searching authority for PCT
2009/0108130 A1 3/2009 Flatt Application Serial No. PCT /US2014 /023284 Publication No. WO / 2014 /
2009/0090238 A1 4/2009 Friedrich 150446 AI ; dated Aug. 1 , 2014 .
2009/0260514 Al 10/2009 Lezock et al . The International Search Report and Written Opinion of the search
2009/0314884 A1 12/2009 Elliot et al . ing authority for PCT Application Serial No. PCT/US2013 /025459 ;
2011/0041632 Al 2/2011 Baker et al . Publication No. WO/ 2013 / 120036 AI ; dated Jul. 23 , 2013 .
2013/0120036 A1 5/2013 Zhu et al . The International Search Report ( ISR ) and Written Opinion of the
searching authority for PCT Application Serial No. PCT/US2012 /
FOREIGN PATENT DOCUMENTS 024558 ; Publication No. WO 2013/119242 AI ; dated Nov. 19 , 2012 .
The ( 113/373 ) International Preliminary Report on Patentability
CN 1705835 A 12/2005 Chapter I for International Patent Application No. PCT/ US2012 /
CN 1827474 A 9/2006 024558 ; Publication No. WO 2013/119242 AI ; dated Aug. 12 , 2014 .
U.S. Patent Feb. 15 , 2022 Sheet 1 of 15 US 11,248,698 B2
127

125
110
136 126 135
L1
L2

146 120b
2
.
FIG
147

130 194 12
129 159 163
158
162 164
120a 193
141 133 143 153
152
121
131
144 153
143 147 193
110 133

131 121
141
FIG
.
1
140
120 125
194 142 134
146 152
U.S. Patent Feb. 15 , 2022 Sheet 2 of 15 US 11,248,698 B2

128
127 161

125
135
dL1 dL2
136 . 126
3
.
FIG
146 120b 147

L2
122
130 '
L1 1631 166! 158
!

1621 164 129

167
143 141 153
159
152
121
120a
U.S. Patent Feb. 15 , 2022 Sheet 3 of 15 US 11,248,698 B2

128
161 127

125

136
dL1 dL2
4
.
FIG
126 135
146 120b 147

"
L2
L1
" 122
167 163
129
159 162 164 166
143 158
152 141 153
121
120a
130
U.S. Patent Feb. 15 , 2022 Sheet 4 of 15 US 11,248,698 B2

161

125
136 126
135
146
147
159
120b
5
.
FIG

167 -152
130
164
162
120a 163

121 141 153 158

122 168
131
172
U.S. Patent Feb. 15 , 2022 Sheet 5 of 15 US 11,248,698 B2

127
161

125
136 126
135
146 .
FIG
6
147
120b

152
130 194
167
163 166
162 164
120a
153
141
122 168
172
U.S. Patent Feb. 15 , 2022 Sheet 6 of 15 US 11,248,698 B2

225
210 226 235
236

296 2 0b 297
8
.
FIG
L1 L2

23
2 0a

221
.

231

210 247
233
231 221
FIG
7
.
:
01

2 0a 234
246
U.S. Patent Feb. 15 , 2022 Sheet 7 of 15 US 11,248,698 B2

325
310 326

347
346 FIG
9
.

330 352

320
383
w 381
321 382
.
331

320c
U.S. Patent Feb. 15 , 2022 Sheet 8 of 15 US 11,248,698 B2

425
410
426
Q

420b
447
446 FIG
10
.

453
-430 452 443

420a 441
IT
.
421

420c
U.S. Patent Feb. 15 , 2022 Sheet 9 of 15 US 11,248,698 B2

536 556 555 525

535 520

510
547 12
.
FIG
593
546
553

594 552 541

543
510
-526 544
544
547 510 543 547
535 533 543
555
526b 531553 535 593
553
583 533 543
525 521
526a 520
15401
532
13
.
FIG 521
534 5401 542
FIG
.
11

581 582
556 552
536 534 594
. 552 520
546 542 542
U.S. Patent Feb. 15 , 2022 Sheet 10 of 15 US 11,248,698 B2

656 625
656 625
610 610
620
15
.
FIG
620 609
17
.
FIG
609

621
621
652 641
643 641
652 643
610
626 -64
635
647
693 643 610
644 w 643 647
655
653
626a 693
620 633 FIG
16
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641
17 17 1640||641 .
FIG
14
626b 540
609 634
655 652
636 694 652 620
694
646 642
.
.
642
U.S. Patent Feb. 15 , 2022 Sheet 11 of 15 US 11,248,698 B2

725
736 726
756

710 746 720

744
726a 794

726b
755
.
FIG
18
.

1 742
SO

752
740
735

747 721 733

734
U.S. Patent Feb. 15 , 2022 Sheet 12 of 15 US 11,248,698 B2

743
753
741
710 793

NI 747
725
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FIG
19
.

755
793

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U.S. Patent Feb. 15 , 2022 Sheet 13 of 15 US 11,248,698 B2

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U.S. Patent Feb. 15 , 2022 Sheet 14 of 15 US 11,248,698 B2
710

FIG . 22

710

22 22

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FIG . 21
U.S. Patent Feb. 15 , 2022 Sheet 15 of 15 US 11,248,698 B2
710

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FIG . 24

710

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24 24

FIG . 23
 US 11,248,698 B2
1 2
MULTIPLE ACTUATOR AND LINKAGE (383 ) configured and arranged to dampen rotation of the
SYSTEM shared link about the first axis . The first member may
comprise a linear spindle (296 ) .
BACKGROUND OF THE INVENTION The first member may comprise a first link ( 152 ) and a
5 second link ( 146 ) , the first link ( 152 ) configured and
The present invention relates generally to the field of arranged for pivotal movement about the third axis ( 134 ) ,
actuator systems, and more specifically to an electrome the second link ( 146 ) configured and arranged for pivotal
chanical redundant actuator. movement about the fourth axis ( 136 ) , and the first link
( 152 ) configured and arranged for pivotal movement about
BACKGROUND ART 10 a seventh axis ( 194 ) relative to the second link ( 146 ) . The
first actuator may comprise a rotary actuator ( 140 ) mounted
Redundant actuator systems are generally known . These on the shared link ( 121 ) and configured and arranged to
systems typically arrange multiple actuators in a way in control rotary movement between the shared link ( 121 ) and
which their displacement is summed , or their torque is the first link ( 152 ) . The second member may comprise a
summed . 15 third link ( 153 ) and aa fourth link ( 147) , the third link ( 153 )
configured and arranged for pivotal movement about the
BRIEF SUMMARY OF THE INVENTION fifth axis ( 133 ) , the fourth link ( 147 ) configured and
arranged for pivotal movement about the sixth axis ( 135 ) ,
With parenthetical reference to the corresponding parts, and the third link ( 153 ) configured and arranged for pivotal
portions or surfaces of the disclosed embodiment, merely for 20 movement about an eighth axis ( 193 ) relative to the fourth
the purposes of illustration and not by way of limitation , the link ( 147 ) . The second actuator may comprise a rotary
present invention provides an actuator system comprising a actuator ( 141 ) mounted on the shared link ( 121 ) and con
shared link ( 121 ) configured and arranged for pivotal move- figured and arranged to control rotary movement between
ment about aa first axis ( 131 ) relative to a reference structure the shared link ( 121 ) and the third link ( 153 ) .
( 120 ) , a controlled element ( 125 ) configured and arranged 25 The seventh axis (494 ) and the eighth axis (493 ) may be
for pivotal movement about a second axis ( 126 ) relative to on the same side of an imaginary line through the third axis
the reference structure ( 120 ) , a first member configured and and the second axis . The seventh axis ( 194 ) and the eighth
arranged for pivotal movement about a third axis ( 134 ) axis ( 193 ) may be on opposite sides of an imaginary line
relative to the shared link and configured and arranged for through the third axis and the second axis . The spring may
pivotal movement about a fourth axis ( 136 ) relative to the 30 be selected from a group consisting
? of a torsional spring , a
controlled element, the third axis ( 134 ) and the fourth axis linear spring, and a flexure . The damper may be selected
( 136 ) offset by a first variable distance (L1 ) , a first actuator from a group consisting of a linear damper and a rotary
( 140 ) configured and arranged to control the first variable damper. The first act and the second iator may
distance, a second member configured and arranged for comprise a stepper motor or a permanent magnet motor. The
pivotal movement about a fifth axis ( 133 ) relative to the 35 first actuator may comprise a motor output shaft and may
shared link and configured and arranged for pivotal move- further comprise a planetary gear stage between the motor
ment about a sixth axis ( 135 ) relative to the controlled output shaft of the first member. The controlled element may
element, the fifth axis ( 133 ) and the sixth axis ( 135 ) offset be a shaft or an aircraft control surface . The controlled
by a second variable distance ( L2 ) , a second actuator ( 141 ) element may be selected from a group consisting of a wing
configured and arranged to control the second variable 40 spoiler, a flap, a flaperon and an aileron . The reference
distance, and the actuators , shared link , first member, second structure may be selected from a group consisting of an
member and controlled element operatively configured and actuator frame, an actuator housing, and an airframe.
arranged such that a change in the first variable distance In another aspect , the invention provides an actuator
rotates the controlled element ( 125 ) about the second axis system comprising an element ( 125 ) configured for rotary
when the second variable distance is constant, and a change 45 movement about a first axis ( 126 ) relative to a reference
in the second variable distance rotates the controlled element structure ( 120 ) , a linkage system connected to the element
( 125 ) about the second axis when the first variable distance ( 125 ) and the reference structure ( 120 ) , the linkage system
is constant. having a link ( 121 ) configured for rotary movement about a
The first, second , third , fourth , fifth and sixth axis may be second axis ( 131 ) relative to the reference structure, the first
substantially parallel to each other. The fourth axis and the 50 axis and the second axis being substantially parallel and
sixth axis may be positioned on opposite sides of an imagi- operatively offset a substantially constant distance , the link
nary line through the third axis and the second axis . The age system configured and arranged such that aa first angle of
fourth axis (536 ) and the sixth axis (535 ) may be positioned rotation ( 161 ) between the element and the reference struc
on the same side of an imaginary line through the third axis ture may be driven independently of a second angle of
and the second axis . The third axis may be coincident with 55 rotation ( 162 ) between the link ( 121 ) and the reference
the fifth axis . The first axis may be coincident with the third structure ( 120 ) , a first actuator ( 140 ) connected to the
axis . The first axis may be coincident with the fifth axis . linkage system and arranged to power a first degree of
The system may further comprise a brake (381 ) config- freedom ( 164 ) of the linkage system , a second actuator ( 141 )
ured and arranged to limit rotation of the shared link about coupled to the linkage system and arranged to power a
the first axis . The actuator system may further comprise a 60 second degree of freedom ( 163 ) of the linkage system , the
brake configured and arranged to hold the first variable first degree of freedom and the second degree of freedom
distance or the second variable distance constant. The sys- being independent degrees of freedom , wherein the first
tem may further comprise a spring (382 ) configured and actuator ( 140 ) may be configured and arranged to drive
arranged to bias rotation of the shared link about the first rotation of the element about the first axis when the second
axis . The system may further comprise a spring configured 65 degree of freedom may be operatively locked .
and arranged to bias rotation of the controlled element about The element may be connected to the reference structure
the second axis. The system may further comprise a damper through a bearing. The link may be connected to the
 US 11,248,698 B2
3 4
reference through a bearing. The linkage system may com- first electric motor ( 140 ) mounted on the shared link ( 121 ) ,
prise five links ( 152 , 153 , 146 , 147 and 121 ) . The linkage the first electric motor ( 140 ) having a drive shaft ( 152 )
system may be connected to the element through a pivot coupled to a proximal end of an upper link (46 ) , a second
joint. The first actuator ( 140 ) may power an angle ( 164 ) electric motor ( 141 ) mounted on the shared link ( 121 ) , the
between two connected links ( 121/152 ) in the linkage sys- 5 second electric motor ( 141 ) having a drive shaft ( 153 )
tem . The first actuator may power a distance between two coupled to a proximal end of aa lower link ( 147 ) , the upper
joints ( 134/136 ) in the linkage system . The first actuator may link ( 146 ) having a distal end pivotally connected ( 136 ) to
comprise a rotary actuator and the rotary actuator may have the controlled element ( 125 ) , the lower link having a distal
an axis of rotation substantially the same as the second axis . end pivotally connected ( 135 ) to the controlled element
The first actuator may comprise a rotary motor or an electric 10 ( 125 ) , whereby actuation of one of the motors while holding
motor. The first actuator may comprise a planetary gear. The the other of the motors still causes rotation of the controlled
first actuator may be mounted on the link . The first actuator link ( 125 ) relative to the reference structure ( 120 ) .
may be connected to the reference through a pivot connec- In another aspect , the invention provides a method of
tion . The system may further comprise a brake configured controlling an actuator system comprising the steps of
and arranged to limit rotation of the link about the second 15 providing an actuator system comprising a shared link ( 121 )
axis . The system may further comprise a brake configured configured and arranged for pivotal movement about a first
and arranged to hold one degree of freedom of the linkage axis ( 131 ) relative to a reference structure ( 120 ) , a controlled
system constant. The system may further comprise a spring element ( 125 ) configured and arranged for pivotal move
configured and arranged to bias rotation of the link about the ment about a second axis ( 126 ) relative to the reference
second axis . The system may further comprise a spring 20 structure ( 120 ) , a first member configured and arranged for
configured and arranged to bias rotation of the element about pivotal movement about a third axis ( 134 ) relative to the
the first axis . The system may further comprise a damper shared link and configured and arranged for pivotal move
configured and arranged to dampen rotation of the link about ment about a fourth axis ( 136 ) relative to the controlled
the second axis. The linkage system may comprise a linear element, the third axis ( 134 ) and the fourth axis ( 136 ) offset
spindle. The spring may be selected from a group consisting 25 by a first variable distance ( L1 ) , a first actuator ( 140 )
of a torsional spring , a linear spring , and a flexure . The configured and arranged to control the first variable distance ,
damper may be selected from a group consisting of a linear a second member configured and arranged for pivotal move
damper and a rotary damper. The first actuator and the ment about aa fifth axis ( 133 ) relative to the shared link and
second actuator may comprise a stepper motor or a perma- configured and arranged for pivotal movement about a sixth a

nent magnet motor. The element may be selected from a 30 axis ( 135 ) relative to the controlled element, the fifth axis
group consisting of a shaft and an aircraft control surface . ( 133 ) and the sixth axis ( 135 ) offset by a second variable
The element may be selected from group consisting of a distance (L2 ) , a second actuator ( 141 ) configured and
wing spoiler, a flap, a flaperon and an aileron. The reference arranged to control the second variable distance, and the
structure may be selected from a group consisting of an actuators , shared link, first member, second member and
actuator frame, an actuator housing , and an airframe. 35 controlled element operatively configured and arranged such
In another aspect , the invention provides an actuator that a change in the first variable distance rotates the
system comprising an element ( 125 ) configured for rotary controlled element ( 125 ) about the second axis when the
movement about a first pivot ( 126 ) relative to a reference second variable distance may be constant, and a change in
structure ( 120 ) , a first linkage ( 146 , 152 , 121 ) connected to the second variable distance rotates the controlled element
the element at a first element connection ( 136 ) offset from 40 ( 125 ) about the second axis when the first variable distance
the first pivot ( 126 ) and extending from the first element is constant, and providing power to the first actuator and the
connection ( 136 ) to a first reference connection ( 131 ) of the second actuator simultaneously such that the controlled
reference offset from the first pivot ( 126 ) , a second linkage element ( 125 ) is rotated about the second axis and the shared
( 147 , 153 , 121 ) connected to the element at a second element link ( 121 ) is held constant about the first axis . The first
connection ( 135 ) offset from the first pivot ( 126 ) and extend- 45 actuator and the second actuator may be provided power in
ing from the second element connection ( 135 ) to a second opposition to each other, whereby backlash in the actuator
reference connection ( 131 ) of the reference offset from the system may be minimized .
first pivot ( 126 ) , the element ( 125 ) and the first linkage In another aspect , the invention provides a method of
forming a first system linkage having at least two indepen- controlling an actuator system comprising the steps of
dent degrees of freedom , the element ( 125 ) and the second 50 providing an actuator system comprising a shared link ( 121 )
linkage forming a second system linkage and having at least configured and arranged for pivotal movement about a first
two independent degrees of freedom , a first motor ( 140 ) axis ( 131 ) relative to a reference structure ( 120 ) , a controlled
connected to the first linkage, a second motor ( 141 ) con- element ( 125 ) configured and arranged for pivotal move
nected to the second linkage and movable independent of the ment about a second axis ( 126 ) relative to the reference
first motor, the first linkage and the second linkages coupled 55 structure ( 120 ) , a first member configured and arranged for
so as to share a degree of freedom , the first motor ( 140 ) pivotal movement about a third axis ( 134 ) relative to the
configured and arranged to power a degree of freedom in the shared link and configured and arranged for pivotal move
first linkage , the second motor ( 141 ) configured and ment about a fourth axis ( 136 ) relative to the controlled
arranged to power a degree of freedom in the second element, the third axis ( 134 ) and the fourth axis ( 136 ) offset
linkage, and one of the motors ( 140 ) configured and 60 by a first variable distance ( L1 ) , a first actuator ( 140 )
arranged to move the element ( 125 ) relative to the reference configured and arranged to control the first variable distance ,
( 120 ) when the other of the motors ( 141 ) operatively locks a second member configured and arranged for pivotal move
the powered degree of freedom . ment about aa fifth axis ( 133 ) relative to the shared link and
In another aspect , the invention provides an actuator configured and arranged for pivotal movement about a sixth
comprising a shared link ( 121 ) pivotally connected ( 131 ) to 65 axis ( 135 ) relative to the controlled element, the fifth axis
a reference structure ( 120 ) , a controlled element ( 125 ) ( 133 ) and the sixth axis ( 135 ) offset by a second variable
pivotally connected ( 126 ) to a reference structure ( 120 ) , a distance (L2 ) , a second actuator ( 141 ) configured and
 US 11,248,698 B2
5 6
arranged to control the second variable distance , and the DESCRIPTION OF THE PREFERRED
actuators , shared link, first member, second member and EMBODIMENTS
controlled element operatively configured and arranged such
that a change in the first variable distance rotates the At the outset, it should be clearly understood that like
controlled element ( 125 ) about the second axis when the 5 reference numerals are intended to identify the same struc
second variable distance may be constant, and a change in tural elements, portions or surfaces consistently throughout
the second variable distance rotates the controlled element the several drawing figures, as such elements , portions or
( 125 ) about the second axis when the first variable distance surfaces may be further described or explained by the entire
is constant, and providing power to the first actuator and the written specification, of which this detailed description is an
10
second actuator simultaneously such that the shared link integral part. Unless otherwise indicated , the drawings are
( 121 ) is rotated about the first axis , whereby a mechanical intended to be read (e.g. , cross -hatching, arrangement of
advantage between the first actuator and rotation of the parts, proportion, degree, etc.) together with the specifica
shared link is adjusted . tion , and are to be considered a portion of the entire written
BRIEF DESCRIPTION OF THE DRAWINGS
15 description of this invention . As used in the following
description, the terms " horizontal ” , " vertical ” , “ left” ,
" right ” , “ up ” and “ down ”, as well as adjectival and adverbial
FIG . 1 is aa front elevation view of aa first embodiment of derivatives thereof (e.g. , “ horizontally ” , “ rightwardly ” ,
the actuator system . " upwardly ” , etc. ) , simply refer to the orientation of the
FIG . 2 is a right side view of the actuator system shown 20 illustrated structure as the particular drawing figure faces the
in FIG . 1 in a first horizontal configuration . reader. Similarly , the terms “ inwardly ” and “ outwardly ”
FIG . 3 is a view of the actuator system shown in FIG . 2 generally refer to the orientation of a surface relative to its
in a first dual motor actuated configuration . axis of elongation, or axis of rotation , as appropriate .
FIG . 4 is a view of the actuator system shown in FIG . 2 Referring now to the drawings, and more particularly to
in a second dual motor actuated configuration . 25 FIGS . 1 and 2 thereof , this invention provides an improved
FIG . 5 is a view of the actuator system shown in FIG . 2 actuator system , of which a first embodiment is generally
in a jam failure actuated configuration. indicated at 110. System 110 is shown in FIGS . 1 and 2 in
FIG . 6 is a view of the actuator system shown in FIG . 2 a horizontal configuration. As shown, system 110 generally
in a modified performance actuated configuration. includes as primary elements aircraft frame 120 , shared link
FIG . 7 is a front elevation view of a second embodiment 30 121 , right actuator 141 , left actuator 140 , right drive arm
of the actuator system . 153 , left drive arm 152 , upper connecting rod 146 , lower
FIG . 8 is a right side view of the actuator system shown connecting rod 147 , and flap 125 .
in FIG . 7 . Aircraft frame 120 acts as a reference structure upon
FIG . 9 is a right side view of aa third embodiment of the 35 which shared link 121 is rotationally mounted through pivot
actuator system . joint 131. Right rotary actuator 141 and left rotary actuator
FIG . 10 is a right side view of a fourth embodiment of the 142 are mounted on shared link 121. Rotary actuators 141
actuator system . and 142 are mounted with their drive shafts coaxial and
FIG . 11 is a front elevation view of a fifth embodiment of aligned along axis 144. In this embodiment, rotary actuators
141 and 142 are permanent magnet electrical servo motors
the actuator system . 40 with planetary gear reduction units. However, other rotary
FIG . 12 is a right side view of the actuator system shown actuators , such as stepper motors or rotary hydraulic actua
in FIG . 11 . tors , may be used as alternatives .
FIG . 13 is a top view of the actuator system shown in FIG . Right actuator 141 forms pivot joint 133 with its output
11 . drive shaft 143 , which is rigidly coupled to one end of right
FIG . 14 is a front elevation view of aa sixth embodiment 45 actuator drive arm 153. The other end of right actuator drive
of the actuator system . arm 153 is connected to one end of lower connecting rod 147
FIG . 15 is a right side view of the actuator system shown through pivot joint 193. The other end of connecting rod 147
in FIG . 14 . is connected to flap 125 through pivot joint 135 .
FIG . 16 is a top view of the actuator system shown in FIG . Similarly, left actuator 140 forms pivot joint 134 with its
14 . 50 output drive shaft 142 , which is rigidly coupled to one end
FIG . 17 is a vertical sectional view of the actuator system of left actuator drive arm 152. The other end of left actuator
shown in FIG . 16 , taken generally on line 17-17 of FIG . 16 . drive arm 152 is connected to one end of upper connecting
FIG . 18 is a front partial perspective view of a seventh rod 146 through pivot joint 194. The other end of connecting
embodiment of the actuator system . rod 146 is connected to flap 125 through pivot joint 136 .
FIG . 19 is a rear partial perspective view of the actuator 55 Flap 125 is rotationally coupled to aircraft frame 120
system shown in FIG. 18 . through pivot joint 126. FIGS . 1 and 2 show flap 125 in a
FIG . 20 is a front view of the actuator system shown in horizontal configuration, in which center line 127 of flap 125
FIG . 18 . is horizontal relative to airframe 120 and thus generally
FIG . 21 is a rear view of the actuator system shown in parallel to horizontal reference line 130 of airframe 120. In
FIG . 18 . 60 this horizontal configuration, left drive arm 152 and right
FIG . 22 is a horizontal sectional view of the actuator drive arm 153 are aligned generally parallel to vertical axis
system shown in FIG . 21 , taken generally on line 22-22 of 129 of airframe 120. Right drive arm centerline 158 forms
FIG . 21 . angle 163 with shared link centerline 122 , which in this
FIG . 23 is a top view of the actuator system shown in FIG . configuration is also equivalent to angle 164 between left
18 . 65 drive arm 152 centerline 159 and shared link centerline 122 .
FIG . 24 is a vertical sectional view of the actuator system Shared linked 121 center line 122 forms angle 162 with
shown in FIG . 23 , taken generally on line 24-24 of FIG . 23 . horizontal reference line 130 of airframe 120 .
 US 11,248,698 B2
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System 110 provides a linkage system with six movable As right actuator 141 causes right drive arm 153 to rotate
rigid links ( 121 , 152 , 153 , 146 , 147 and 125 ) , eight pivot counterclockwise, lower control rod 147 is forced right
joints ( 131 , 133 , 134 , 193 , 194 , 135 , 136 and 126 ) , and two wards. As control rod 147 is forced rightwards, flap 125 is
fixed reference points 120a and 120b . Note that left and right pushed rightwards at joint 135 , urging flap 125 to rotate
actuators 140 , 141 are classified as pivot joints 133 , 134 in 5 counter clockwise. Similarly, as left actuator 140 causes left
terms of the linkage system since their output shafts pivot drive arm 152 to rotate counterclockwise, upper control rod
about an axis of rotation , in this embodiment a common axis 146 is forced leftwards. As control rod 146 is forced
of rotation 144. All of the pivot joints are orientated gener leftwards, flap 125 is pulled leftwards at joint 136 , also
ally parallel to axis 144 .
There are two linkage paths formed between first fixed 10 Whenflapboth125actuators
urging to rotate counter clockwise .
are working normally in this dual
reference point 120a and second fixed reference point 120b , motor actuation mode , right drive arm 153 will rotate
which together form the linkage system . The first linkage counterclockwise 166 the same general amount as left drive
path is defined, from airframe reference 120a to right arm 152 rotates counter clockwise 167 , causing the drive
airframe reference 120b as pivot joint 131 , shared link 121 ,
left actuator 140 acting as pivot joint 134 , drive arm 152 , 15 arms to remain generally parallel. Similarly, the reduction
pivot joint 194 , upper connecting rod 146 , pivot joint 136 , dL1 in distance L1 between pivot joint 136 and pivot 134 is
flap 125 , and pivot joint 126. Such a linkage path is about the same amount as the increase dL2 in distance L2
commonly referred to as a four member linkage since there between pivot joint 135 and pivot 133. Because upper
are four rigid members. Similarly, the second linkage path is connecting rod 146 moves to the left the same amount as
defined , from left airframe reference to right airframe ref- 20 lower connecting rod 147 moves to the right, shared link 121
erence 120b , as pivot joint 131 , shared link 121 , right remains substantially fixed in rotational position relative to
actuator 141 acting as pivot joint 133 , drive arm 153 , pivot air frame 120 .
joint 193 , lower connecting rod 147 , pivot joint 135 , flap The dual motor actuation mode is effectively causing the
125 , and pivot joint 126. The second linkage path is also a linkage system to act on flap 125 by both pushing and
four member linkage. There are elements shared in both 25 pulling at the same time , with one connecting rod pushing
linkage paths, including pivot joint 131 , shared link 121 , flap while the other connecting rod pulls . While actuator 141
125 , and shared pivot joint 126. In other words, three of the pushes shared link 121 leftwards, actuator 140 pulls shared
rigid members in each of the four member linkages are link 121 rightwards. The torque output of left actuator 140
shared . and the torque output of the right actuator 141 are both
The linkage system contains two independent degrees of 30 translated by connecting rods 146 and 147 to act on moving
freedom . More specifically, the positions of all of the links flap 125. The linkage system is configured and arranged
and joints relative to the reference ( airframe 120 ) can be such that left and right actuators 140 , 141 contribute
defined by two numbers. By controlling the pivot joint angle approximately equal torques on flap 125 . owever, there are
164 that left actuator 140 makes with shared link 121 , and other modes of operation, discussed in the following sec
the pivot joint angle 163 that right actuator 141 makes with 35 tions , in which the actuators provide unequal or opposing
shared link 121 , one can independently control two degrees torques.
of freedom of the linkage system . The degrees of freedom of FIG . 4 shows system 110 in a configuration in which flap
the linkage system and each linkage path will become more 125 has been rotated clockwise by angle 161 from the
apparent in the following sections discussing system 110 in configuration shown in FIG . 1. Drive arm 152 has been
various actuated configurations. 40 rotated clockwise by angle 167 such that drive arm 152 now
FIG . 3 shows system 110 in a configuration in which the forms angle 164 with shared link centerline 122. Drive arm
system has been actuated by the concerted effort of both left 153 has been rotated clockwise by angle 166 such that drive
and right actuators 140 and 141 in a dual motor actuation arm 153 now forms angle 163 with shared link centerline
mode of operation . Flap 125 has been rotated counter 122. Angle 167 and angle 166 are substantially equal such
clockwise by angle 161 from the configuration shown in 45 that drive arm 153 and drive arm 152 are still parallel.
FIG . 1. Angle 162 that shared link 121 makes with airframe Shared link 121 has not moved and still forms angle 162
horizontal reference 130 has not changed from its angle in with reference horizontal 130. Distance L1 between pivot
the horizontal configuration shown in FIGS . 1 and 2. Dis- joint 136 and pivot 134 has been increased by dL1 to Ll ' and
tance L1 between pivot joint 136 and pivot 134 has been distance L2 between pivot joint 135 and pivot 133 has been
reduced by dL1 to Ll ' and distance L2 between pivot joint 50 decreased by dL2 to L2 ' .
135 and pivot 133 has been increased by dL2 to L2 ' . System 110 is capable of continuing to operate after one
Right actuator 141 has caused right drive arm 153 to of the actuators has jammed in a jam failure actuation mode .
rotate counterclockwise by angle 166 relative to shared link This jam failure configuration is shown in FIG . 5. In this
121 , decreasing angle 163 between right drive arm 153 and configuration, right actuator 141 is treated as having failed
shared link centerline 122 , and increasing distance L2 by 55 with a locked output shaft ( i.e. closed failure or jam) , and
dL2 to L2 ' . Similarly, left actuator 140 has caused left drive system 110 has been actuated from the horizontal configu
arm 152 to rotate counterclockwise by angle 167 relative to ration shown in FIG . 1 by left actuator 140 .
shared link 121 (which is equivalent to angle 166 in this Because right actuator 141 has jammed, output shaft 143
second configuration ), decreasing angle 164 between right is effectively rigidly coupled to shared link 121 , and angle
drive arm 152 and shared link centerline 122 , and decreasing 60 163 between drive arm 153 and shared link center line 122
distance L1 by dL1 to L1 ' . Angle 164 between left drive arm will not change. Shared link 121 , actuator 141 , and drive
152 and shared link 121 has been decreased by angle 167 , arm 153 now form a single rigid member or link . The second
such that angle 163 still equals angle 164. Right drive arm linkage path through actuator 141 , which was originally a
centerline 158 of right drive arm 153 and left drive arm four rigid member link with five pivot joints, is now a three
centerline 159 of left drive arm 152 are still aligned with 65 member link with four pivot joints . The first linkage path
each other but are no longer aligned with reference vertical through left actuator 140 is still aa four member link , since the
axis 129 . actuator in its path has not jammed. The total linkage system
 US 11,248,698 B2
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is now defined by only one degree of freedom . This single Neither actuator will be actuated to pull its corresponding
degree of freedom can be controlled by still working left connecting rod in this mode ( unless there is a failure
actuator 140 . condition which is being addressed ). Alternatively, the mini
As shown in FIG . 5 , right drive arm centerline 158 of right mize backlash mode may be implemented in the same
drive arm 153 and left drive arm centerline 159 of left drive 5 manner but by directing the actuators to always pull their
arm 152 are no longer in alignment. Since right actuator 141 corresponding connecting rod , instead of pushing . While the
has jammed, angle 163 between right drive arm 153 and minimize backlash mode may cause increased friction or
shared link centerline 122 is locked or jammed at the same power usage , it offers aa method of operating system 110 with
angle relative to shared link centerline 122 as in the hori- virtually no backlash .
zontal configuration shown in FIGS . 1 and 2. However, left 10 A configuration for operating system 110 in a modified
drive arm 152 has been moved clockwise by angle 167 performance mode is shown in FIG . 6. Modified perfor
relative to shared link 122 to cause an increase in angle 164 mance mode provides a method of varying the mechanical
between centerline 159 of left drive arm 152 and shared link advantage between system actuators 140 , 141 and flap 125 .
centerline 122 . Comparing the configurations shown in FIG . 6 to FIG . 1 ,
As left actuator 140 drives left drive arm 152 clockwise , 15 even though flap 125 is positioned horizontally in both
upper connecting rod 146 is pushed rightwards. As upper configurations, drive arms 152 , 153 and shared link 121
connecting rod 146 is pushed rightwards, flap 125 is pushed have been adjusted in the configuration shown in FIG . 6 .
rightwards through joint 136. This will urge flap 125 to More specifically, shared link 121 has been rotated clock
rotate clockwise relative to air frame 120. Lower connecting wise by angle 168 , drive arm 152 has been rotated clockwise
rod 147 will move leftwards as flap 125 rotates clockwise . 20 by angle 167 , and drive arm 153 has been rotated counter
Since right actuator 141 is jammed, right drive arm 153 and clockwise by angle 166 .
shared link 121 act as a single rigid body, and as lower With this adjustment, the mechanical advantage between
connecting rod 147 moves leftwards, shared link 121 also actuators 140 , 141 and flap 125 has been increased . This is
must move leftwards (rotate clockwise about 131 ) . Shared perhaps most easily observed when considering the amount
link 121 is rotated clockwise by angle 168 from its old 25 that control rod 146 moves to the right for a given clockwise
centerline position 172 to its current centerline position 122 . rotation of drive arm 152. In FIG . 1 , since drive arm 152 is
As shown in FIG . 5 , in this configuration angle 162 between perpendicular to drive connecting rod 146 , a clockwise
horizontal reference 130 and shared link centerline 122 has rotation of drive rod 152 will move connecting rod 146 to
increased from angle 162 in the configuration shown in FIG . the right aa maximal amount. Pivot joint 194 will move with
4. 30 only a horizontal component. Comparing FIG . 1 to FIG . 6 ,
Thus, even though right actuator 141 has jammed, left since drive arm 152 makes an oblique angle with connecting
actuator is able to actuate flap 125 clockwise and counter rod 146 in the FIG . 6 configuration , rotation of drive arm
clockwise . Instead of having two actuators pushing off each 152 will cause both rightwards and downwards movement
other, which keeps shared link 121 still , as in the dual of pivot joint 136. Since the movement is “ split” between
actuation mode shown in FIG . 4 ,one actuator pushes off of 35 both horizontal and vertical components, connecting rod 146
shared link 121 , and in response to the corresponding does not move as much to the right for a given angle of
rotation of shared link 121 , a torque is provided to flap 125 . rotation of drive arm 152 compared to the configuration
In this example, for a given rotation amount of left shown in FIG . 1. Effectively , the mechanical advantage in
actuator 140 , flap 125 will rotate less than it would in the the linkage system is adjusted by varying angle 162 that
dual actuation mode , in which both left actuator 140 and 40 shared link 121 makes with airframe 120 horizontal refer
right actuator 141 rotate . For example, in comparing FIG . 4 ence 130. By being able to adjust the mechanical advantage,
and FIG . 5 , it can be seen that for an equivalent rotation of flight characteristics can be modified, such as the maximum
flap 125 by angle 161 , angle 164 , which drive arm 152 rate of movement of flap 125 , the maximum angular dis
makes with shared link centerline 122 , is significantly placement of flap 125 , the backlash, the maximum torque
greater in FIG . 5 compared to FIG . 4 . 45 that can be applied to flap 125 , and the natural resonant
System 110 can also be operated in a minimize backlash frequency of the system .
mode , in which right actuator 141 and left actuator 140 are As shown in FIGS . 1-6 , system 110 has two independent
commanded to apply a constant torque in opposition to each degrees of freedom . In other words, given a fixed reference
other in order to minimize backlash experienced in actuating air frame 120 , the positions of all other elements and pivot
flap 125. In other words, both actuators 140 and 141 may be 50 joints can be defined by two independent variables, X and Y ,
configured to either always push or always pull against their in which X and Y may be varied independently from each
respective connecting rods 146 , 147 , and flap 125 is moved other. For example, angle 161 between flap 125 centerline
by controlling which actuator works harder. 127 and horizontal reference 128 , and angle 162 between
For example, if operating in aa minimize backlash mode in horizontal reference 130 and shared link center line 122
which both actuator drive arms 152 , 153 are configured to 55 define two independent variables specifying the two degrees
push against their corresponding connecting rods 146 , 147 , of freedom in the system . Flap angle 161 can be varied
respectively, right actuator 141 is commanded to drive arm independently of shared link angle 162 , as shown in the
153 counterclockwise with a small minimum torque while configuration in FIG . 3. Alternatively, shared link angle 162
left actuator 140 is commanded to drive arm 152 clockwise can be adjusted as the flap angle 161 is held constant, as
with an equivalent minimum magnitude torque. In this case , 60 shown in the configuration in FIG . 6. Thus, flap angle 161
connecting rods 146 and 147 will be constantly driven and shared link angle 162 are independent variables . For a
rightwards. This creates a tension in the linkage system given flap angle 161 and shared link angle 162 , angles 163
which will drive the internal contact interfaces of all the and 164 of drive arms 152 and 153 are fixed . There are only
joints to one side, such that backlash is minimized . To move two degrees of freedom in the system , such that two
flap 125 , either actuator 140 or actuator 141 , depending on 65 degrees are held constant (angle 161 and 162 ) , the whole
the desired direction of rotation of flap 125 , applies an system is fixed . One can alternatively define angles 163 and
increased torque in order to push its connecting rod harder. 164. For a given angle 163 and angle 164 , flap angle 161 and
 US 11,248,698 B2
11 12
shared link angle 162 are fixed . Left actuator 140 is arranged 383 are useful for changing the operating dynamics of the
to directly control angle 164. Similarly, right actuator 141 system , such as reducing backlash and vibration.
controls angle 163. By being able to control actuator angles Brake 381 is arranged to lock the position of shared link
140 and 141 , and therefore actuator angles 163 and 164 , one 321 relative to reference 320. When system 310 is operating
can control flap angle 161 and shared link angle 162. 5 in dual motor actuation mode , operation of system 310 is
Because there are two degrees of freedom , even if one of the substantially equivalent to the operation of system 110. The
actuators becomes locked, making the system now a single effect of spring 382 , damper 383 , and brake 381 is important
degree of freedom system , the other actuator can still cause when an open failure occurs in one of the actuators. An open
failure is when the actuator is no longer capable of applying
a change in flap angle 161 .
In general, system 110 has a mechanical linkage which is 10 aactuator
torque tofailure
its output shaft,above
described
and iswith
in contrast
> to the jammed
references to FIG . 5 .
made up of two partially dependent linkage paths. Each An open failure in system 110 is problematic because ,
linkage path has two degrees of freedom . The linkage paths without brake 381 , flap 125 would be free to move up and
share one degree of freedom (angle 121 ) . Each linkage path down regardless of the action of the remaining working
has an actuator along its path that controls one of its degrees 15 actuator. This is due to the fact that the system is a two
of freedom . By controlling both actuators , all degrees of degree of freedom system , and when one degree of freedom
freedom of the system are defined . If one of the degrees of is uncontrolled (i.e. open actuator failure ) the complete
freedom becomes locked, the other degree of freedom in the kinematic state of the system can not be controlled . How
system can be used to change the angle of the flap. This ever, because of brake 381 in system 310 , an open failure
results in jam resistance . Also , by having a second degree of 20 can be handled . If an open failure occurs , brake 381 is
freedom , the degree of freedom which is independent of the activated to lock shared link 321 , effectively converting the
flap angle can be used to adjust the mechanical advantage of linkage system into a single degree of freedom system . The
the system , or to test the system during use without adjusting single degree of freedom system can then be actuated by the
the flap angle. remaining working actuator to control flap 325 , as described
A second embodiment 210 of the system is shown in 25 with reference to FIG . 5 .
FIGS . 7 and 8. In this embodiment, the drive arms 152 , 153 A fourth embodiment 410 is shown in FIG . 10. In this
and connecting rods 146 , 147 in system 110 have been embodiment, the drive arm configuration has been inverted .
replaced by linear spindles 296 and 297. Similar to first More specifically, drive arm 452 and drive arm 453 are
embodiment 110 , system 210 is defined by a mechanical arranged on the same side of a horizontal reference line
linkage having two linkage paths between two positions 30 extending through the axis of rotation 443 of actuator 441
220a , 220b on reference 220. The first linkage path is and pivot joint 426. In this configuration, the torque that
defined from reference 220a to reference 220b and com- actuator 441 applies to drive arm 453 is reversed compared
prises pivot joint shared link 221 , pivot joint 233 , linear to the previous configurations. For example, referring to
spindle 297 , pivot joint 235 , flap 225 , and pivot joint 226 . FIG . 10 , when drive arm 453 pushes rightward against
The second linkage path also is defined from reference 220a 35 connecting rod 447 , a counteracting counter clockwise
to reference 220b but comprises pivot joint 231 , shared link torque is applied to shared link 421. In comparison , referring
221 , pivot joint 234 , linear spindle 296 , pivot joint 236 , flap to FIG . 9 , as drive arm 353 pushes rightward on connecting
225 , and pivot joint 226. Linear spindle 296 allows the rod 347 , a counteracting clockwise torque is applied to
distance L1 between joint 234 and pivot joint 236 to be shared link 321. As drive arm 453 pushes rightward against
adjusted. Similarly , linear spindle 297 allows the distance L2 40 connecting rod 447 and applies a counter clockwise torque
between pivot joint 233 and pivot joint 235 to be adjusted . on shared link 421 as described , drive arm 452 pulls leftward
Each linear spindle acts as an independent degree of free- on connecting rod 446 , and applies a counteracting clock
dom in the mechanical linkage system of embodiment 210 . wise torque on shared link 421. The counter clockwise
System 210 can be operated in the dual motor actuation torque applied to shared link 421 by drive arm 453 is
mode described for system 110. For example, if linear 45 canceled by the clockwise torque applied by drive arm 452 .
spindle 296 is shortened while linear spindle 297 is elon- This allows for reallocating mechanical strain on the
gated , flap 225 will be rotated clockwise while shared link mechanical linkage system .
221 remains still . A fifth embodiment 510 is shown in FIGS . 11-13 . System
Additionally, system 210 will continue to work in the jam 510 is optimized as a stand alone package that can be easily
failure actuation mode described for system 110. For 50 transported and replaced as a line replaceable unit. More
example , if linear spindle 297 jams, adjustment of linear specifically, system 510 includes its own reference 520 ,
spindle 296 will continue to change the angle of flap 225 , which merely needs to be affixed to an external reference
since rotation of shared link 221 will allow the position of such as an airframe. There is no longer a need to mount
pivot joint 235 to change. multiple points of the linkage system to an external refer
A third embodiment 310 of the system is shown in FIG . 55 ence . Also , shared link 521 in system 510 is now mounted
9. System 310 is identical to system 110 but with the with an axis of rotation which is coincident with the axis of
addition of spring 382 , damper 383 , and brake 381. Spring rotation of actuators 540 and 541. Also , system 510 has an
382 is positioned between shared link 321 and airframe inverted connecting rod structure .
reference 320c . In the horizontal configuration shown in Reference frame 520 of system 510 acts as the linkage
FIG . 9 , spring 382 is in an uncompressed state . However, 60 system reference structure . Shared link 521 is a small disk
any movement of shared link 321 from its position in FIG . to which left rotary actuator 540 and right rotary actuator
9 will cause spring 382 to apply a restoring force or torque. 541 are mounted . Right actuator output shaft 543 passes
Spring 382 may be a linear coil spring, a flexure, or a through bearing joint 531 of frame 520. Thus, right output
torsional spring arranged about pivot joint 331. Spring 382 shaft 543 is arranged to rotate about axis 544 relative to
may alternatively be placed about pivot joint 326. Damper 65 frame 520. Similarly, left output shaft 542 passes through
383 is arranged to dampen the rotation of shared link 321 bearing joint 532 of frame 520 and is arranged to rotate
relative to reference structure 320. Spring 382 and damper about axis 544 relative to frame 520. Shared link 521 may
 US 11,248,698 B2
13 14
be configured to rotate about axis 544 together with the Actuators 740 and 741 are mounted upon shared link 721 ,
stators of actuator 540 and 541. In other words, output shafts and also have their output shaft axes of rotation coincident
542 and 543 can be held fixed relative to frame 520 while with axis 744. Actuators 740 and 741 are rotary motors with
shared link 521 , actuator 540 , and actuator 541 all rotate output planetary gear stages . Output shaft 742 of right
together relative frame 520 . 5 actuator 740 is splined and rigidly coupled to drive arm 752 .
Drive arm 553 is rigidly mounted on output shaft 543 , and Right drive arm 752 is connected to the left side of con
drive arm 552 is rigidly mounted on output shaft 542. Drive necting rod 746 through pivot joint 794. The right side of
arm 553 connects to connecting rod 547 through pivot joint connecting rod 746 is coupled to drive arm 756 through
593. Similarly , drive arm 552 connects to connecting rod pivot joint 736. Drive arm 756 is rigidly coupled to system
546 through pivot joint 594. Connecting rod 546 connects to 10 output shaft 726. System output shaft 726 is mounted to
receiving arm 556 through pivot joint 536. Similarly, con- frame 720 through bearings 726a and 726b for rotary
necting rod 547 connects to receiving arm 555 through pivot movement about axis 726. Output shaft 743 of actuator 741
joint 535. Receiving arm 555 and receiving arm 556 are both is splined and rigidly connected to drive arm 753. Drive arm
rigidly mounted to system output shaft 525. In other words , 753 is connected to connecting rod 747 through pivot joint
arms 555 and 556 do not rotate separately from shaft 525. 15 793. Connecting rod 747 is connected to drive arm 755
Output shaft 525 is configured to drive an external load , such through pivot joint 793. Drive arm 755 is rigidly coupled to
as an aircraft flap. system output shaft 725 .
Due to the similarity in the inverted connecting rods, the The operation of system 710 is similar to operation of the
operation of system 510 is similar to system 410. For other embodiments . Each actuator controls a single degree
example, with reference to FIG . 12 , in order to drive system 20 of freedom in a two degree of freedom system . In system
output shaft 525 clockwise, drive arm 553 should push 710 , actuators 740 and 741 torque off of each other across
rightwards on connecting rod 547 and drive arm 552 should shared link 721 in order to both cause a push force or both
push also rightwards on connecting rod 546. The torque cause a pull force on connecting rods 746 and 747. In other
applied by right actuator 541 on drive arm 553 is equal and words, actuator 740 is driven to apply a torque equal and
opposite the torque applied on drive arm 552 by left actuator 25 opposite to shared link 721 as the torque applied by actuator
540. Since the torques applied by actuator 540 and 541 741. As viewed from the perspective in FIG . 18 , if the torque
cancel each other out , shared link 521 does not rotate applied by actuator 740 causes a clockwise torque on shared
relative to frame 520 as output shaft 525 is rotated clock- link 721 (which causes connecting rod 746 to be pushed
wise . rightwards ), actuator 741 will be driven to cause a counter
In the event of a jam failure of one of the actuator, the 30 clockwise torque on shared link 721 (which causes a right
other actuator will continue working, as in system 110 and wards force pushing on connecting rod 747 ) . System output
described with reference to FIG . 5. However, shared link shaft 725 will thus be driven clockwise, while shared link
521 ( along with ators 540 and 541 ) will rotate relative 721 experiences no net torque .
to frame 520 as output shaft 525 rotates. In order to handle The bearing configuration of system 710 is shown in FIG .
open actuator failures, a brake, spring, or damper is placed 35 20. Outer sheath 701 acts as a unitary member with frame
between shared link 521 and reference frame 520 , as 720. Bearings 702 allow cylinder 703 to rotate about axis
described in system 410 . 744 relative to frame 720. Bearings 705 , held in place by
A sixth embodiment 610 is shown in FIGS . 14-17 . In this cylinder 704 , allow inner cylinder 706 to also rotate about
embodiment, shared link 621 has been configured for sliding axis 744 relative to frame 720. Planetary gears 707 operate
engagement with frame 620. As shown, frame 620 has 40 between inner cylinder 706 and gear carrier 708 .
opening 609 , which is configured to receive shared link 621 System 710 has a very compact form factor with rela
in sliding engagement. Shared link 621 does not rotate tively large bearings for the overall size of system 710 .
relative to frame 620. During dual motor actuation mode Having relatively large bearings helps produce a system
operation , shared link 621 does not slide relative to frame with a particularly high estimated mean time between fail
620. However, in jam failure operation mode , left and right 45 ures.
movement of shared link 621 relative to frame 620 provides The disclosed actuator system and method resulted in
the linkage system with the necessary degree of freedom to several surprising advantages. The disclosed actuator system
continue to operate through the jam failure . is smaller, lighter, and faster than current hydraulic actua
Seventh embodiment system 710 is shown in FIGS . tors . The disclosed actuator system uses power only when
18-24 . System 710 is very similar in general structure and 50 needed , and does not have the continuous waste associated
operation to fifth embodiment system 510 shown in FIGS . with maintaining a hydraulic high pressure and compensat
11-13 . However, system 710 has larger bearings 726a and ing for hydraulic valve leakage . Additionally, electronic
726b supporting system output shaft 725 in rotating engage- actuator controls provide higher bandwidth control than is
ment with frame 720. Similarly, bearings 733 and 734 possible with a hydraulic valve . Further, complex seals
support actuators 740 and 741 and shared link 721 in 55 necessary in hydraulic actuators are not needed in the
pivoting relationship with frame 720. System 710 provides disclosed actuator system and method .
a compact, line replaceable unit with high mean time The disclosed actuator system and method, due to its
between failure . novel and unique structure , continues to work through a jam
As shown in FIGS . 18 and 19 , actuator system 710 failure . The jam failure handling works inherently in the
comprises as primary elements frame 720 , system output 60 disclosed system , without aa need for release clutches . Addi
shaft 725 , right actuator 740 , left actuator 741 , shared link tionally, the disclosed actuator system can be configured
721 , drive arm 752 , drive arm 753 , connecting rod 746 , and with a single brake to be able to handle an open actuator
connecting rod 747 . failure in either actuator. Current redundant electromechani
Frame 720 acts as both a housing and a reference structure cal actuators need two brakes in order to handle an open
upon which the actuator system bearings interact. For 65 failure in either system .
example, shared link 210 is mounted by bearings 733 and Further, the disclosed actuator system and method inher
734 for rotary motion relative to frame 720 about axis 744 . ently increases actuator lifetime, since each actuator will
 US 11,248,698 B2
15 16
typically provide only half of the work provided by the freedom and said second degree of freedom being
actuator system . The disclosed actuator system will continue independent degrees of freedom ;
working through either an actuator jam failure or an actuator wherein said first actuator is configured and arranged to
open failure , and the malfunctioning actuator can be easily drive rotation of said element about said first axis when
replaced at a later time after further operation . The disclosed 5 said second degree of freedom is operatively locked .
actuator system also provides the novel ability to be able to 2. The actuator system as set forth in claim 1 , wherein said
adjust the mechanical advantage of the system during opera- linkage system comprises:
tion . Further, a mode of operation is provided in the dis a first linkage connected to said element at a first element
closed system in which backlash can be minimized . The dual connection offset from said second axis and extending
degree of freedom nature of the system also allows for the 10 from said first element connection to a first member
ability to conduct system self tests during operation , without connection offset from said first axis ;
needing to change the actuator output. All of these advan a second linkage connected to said element at a second
tages and varied modes of operation are available real time element connection offset from said second axis and
in the disclosed system , i.e. the system does not need to be extending from said second element connection to a
shut down and stopped in order to be reconfigured. 15
second member connection offset from said first axis ;
Various alternative embodiments of the disclosed actuator
system and method are also possible . For example, the a first member connected to said first linkage and said first
motors can be configured to operate with dynamic braking rotary actuator;
or regeneration . The motor drivers, dynamic braking resis said first member configured and arranged for rotary
tor, and regeneration capacitor can be combined with the 20 movement about a third axis relative to said link ;
disclosed embodiments. Additionally, position sensors , such a second member connected to said second linkage and
as encoders or resolvers, can be added at some of the pivot said second rotary actuator; and
joints together with a servo controller to form a complete said second member configured and arranged for rotary
servo system . Heat sensors can be added to help detect and movement about a fourth axis relative to said link .
diagnose bearing and / or motor malfunction . Torque sensors 25 3. The actuator system as set forth in claim 2 , wherein :
2

can be added to the output or drive shafts to provide further said first rotary actuator is configured and arranged to
operation monitoring and feedback signals. control rotation of said first member ;
Therefore , while the presently -preferred form of the said second rotary actuator is configured and arranged to
actuator system and method has been shown and described , control rotation of said second member;
and several modifications discussed, persons skilled in this 30 said first rotary actuator, said first member and said first
art will readily appreciate that various additional changes linkage are configured and arranged to rotate said
may be made without departing from the scope of the element about said second axis relative to said refer
invention. ence structure when said second rotary actuator opera
The invention claimed is : tively locks rotation of said second member about said
1. An actuator system comprising: 35 fourth axis relative to said link ; and
an element configured for rotary movement about a first said link , said first and second members and said first and
axis relative to a reference structure; second rotary actuators configured and arranged such
a linkage system connected to said element and said that said link rotates about said first axis when said
reference structure ; second rotary actuator operatively locks rotation of said
said linkage system having a link configured for rotary 40 second member about said fourth axis relative to said
movement about a second axis relative to said reference link .
structure ; 4. The actuator system as set forth in claim 2 , wherein said
said first axis and said second axis being substantially first, second , third , and fourth axis are substantially parallel
parallel and operatively offset a substantially constant to each other.
distance ; 45 5. The actuator system as set forth in claim 2 , wherein said
said linkage system configured and arranged such that a first member connection and said second member connec
first angle of rotation between said element and said tion are positioned on opposite sides of an imaginary line
reference structure may be driven independently of a through said first axis and said second axis or said first
second angle of rotation between said link and said element connection and said second element connection are
reference structure; 50 positioned on the same side of an imaginary line through
a first rotary actuator connected to said linkage system said first axis and said second axis .
and arranged to rotationally control first degree of 6. The actuator system as set forth in claim 2 , wherein said
freedom of said linkage system ; third axis is coincident with said fourth axis .
a second rotary actuator coupled to said linkage system 7. The actuator system as set forth in claim 6 , wherein said
and arranged to rotationally control a second degree of 55 first axis is coincident with said third axis .
freedom of said linkage system , said first degree of