Note: Descriptions are shown in the official language in which they were submitted.
~ 308? ~ 8
2 DOCKET NO. 171~.03
~ACKGROVND OF TH~ INVENTION
Field of the Invention:
The invention relates to mechanisms of contractility,
and to systems utilizing "McKibben" muscles.
Description of the Prior Art:
Contractility describes the fundamental mechanism by
which motion or movement is accomplished by living matter.
Contractility is thought to result from the interaction of
various fibrillar (contractile) proteins within the living
cell. The contractile properties of ~uch proteins are
thought to primarily result from chemical interactions.
Accordingly, investigations of the contractile properties of
muscle cells primarily focus on the chemical aspects
(reactions), rather than the mechanical aspects of
contraction.
It is generally believed that two types of filament
structures form the contractile machine in a muscle, ie, a
"thick" filament composed primarily of myosin and a "thin"
filament which contains actin. It has been discovered that
the filaments, whether thick or thin, do not change in
length as a muscle cell contracts from its relaxed state.
It is also known that "thin" filaments are attached at
either end of the muscle cell and that the "thick" fil2ments
bind to the "thin" filaments. It has been hypothesized
that the "thin" filaments mechan~cally slide by the "thick"
filaments.
The magnitude of the change in the overall length
of the muscle cell during contraction is t~pically less than
3 microns. In ~act the sarcomere length of ome ~keletal
muscles is only about 2.5 microns indicating that cuch
1 308?~1 8
3 DOCKET NO. 1717.03
skeletal muscles do not signifigantly shorten during
contraction.
Summarizing, muscle cells and muscles have the
capability of producing very large forces upon contraction.
Muscles also tend to increase in diameter as they contract.
However, the mechanical aspects of the contractility
mechanism of a muscle cell are not well understood.
Mechanical systems simulating the action of a
muscle described in the literature typically include an
expandable bladder confined and/or co~strained to expand
radially when pressurized with a gas. For example, a
Brevet D' Invention published October 15, 19~1 in the
Republic of France, No. 2.076.768 describes a device for
converting fluid pressure into contractile force and
includes an ovoidal rubber envelope reinforced with
relatively inelastic longitudinal filaments. The ends of
the ovoidal envelope are anchored between two points and the
envelope pressurized wlth a gaseous fluid causing the
ovoidal envelope to expand diametrically and contract
longitudinally pulling the anchor points together.
Similarly, United States Patent No. 3,645,1~3, Yarlott,
describes an ovoidal envelope defined by an expandable
bladder confined within relatively inelastic longitudinal
strands such that the bladder can expand diametrically but
not longitudinally when pressurized with a gaseous fluid.
The earlist k~own mechanical system which simulated
the action of a muscle known as the "McKibben S~nthetic
Muscle" comprised a cylindrical sheath woven ~rom helical
strands of an inGlastic material surrounding a gas
inflatable bladder, and was designed to articula~e
orthopedic and prosthetic appliances for polio victims.
~ hile ga~ has advantages as a med~um ~or
pressurizing and expanding "McKibben" type contractile
ac~uators or muscles, i~s primary disadvantage is that it
is compres~ible which dictates an "21astic" contractile
4 1 3 0 8 - 1DOCKET NO. 1~1~,03
response. Elastic contractile responses are not always
desirable. For example, an elastic contractile mechanism
can not establish or maintain a reference position ~7here
load varies.
Also, as explained infra, the contractile force
generated by a "McKibben" type contractile device as it
inflates is not linear, and when a gas is utilized to
inflate or "energize" the muscle, the contractile position
of the muscle will vary with ~as pressure and tensile load.
Accordingly, any system utilizing gas inflatable "McKibben"
type contractile devices requires complex electromechanical
or other type of servomechanisms both for adjusting
position, and for metering the gas for inflating and
deflating under conditions of varying pressure.
Still another significant disadvantage of using a
gas for inflating and contracting a "McKibben" muscle
relates to the property of gas to expand filling the
available volume. This means that the degree of contraction
(or extension) of the muscle is determined by the tensile
force between the anchor points of the muscle resisting
contraction.
The above reasons, among others have discouraged
commercial acceptance of the "McKibben" muscle as a
contractile force generating mechanism/actuator.
Summarizing, gas energized contractile force
mechanisms have three variables, position (volume),
pressure and tension. Temperature also af~ects the response
of such gas energized systems. For the "McKibben" type
contractile force mechanisms to achieve commercial
acceptance , it i5 necessary to eliminate or minimize the
above variables affecting its re~ponse.
SUMMARY 0~ THE INV~NTION
A contractility actuator i5 described which includes a
~ylindrical array formed by a network o~ open two
dimensional guadrilateral segments, and expandable bladder
1 308~ 1 8
DOCKET NO. 1~1~.03
located within the cylindrical network and meahs introducing
and expanding the bladder with a liquid for generating a
very large magnitude contractile force aligned with the axis
of the array. Two or more of the described contractility
actuators may be arranged in a system for precisely
articulating one or more arms pivotally secured at the
distal end of a ridged structure.
Th~ principal aspect of the invented contractility
actuator relates to the incompressible properties of liquids
which reduces the number of variables allowing the actuator
to precisely respo~d relative to both position and tension.
Accordingly, two or more such actuators working in
opposition acro~s a fulcrum establish a dynamic equilibrium
which can be incremently altered by simultaneously inputting
liquid into actuators on one side of the fulcrum and
allowing liquid to exhaust from the actuators on the other
side of the fulcru~ to establish a new dynamic equilibrium
position without oscillation.
Another aspect of the invention relates to utilization
of a combination of liguid and gas inflated contractility
actuators for pivoting arms at the di6tal ends of structure
member~ providing a combination of the elastic positional
response characteristics of a gas inflated contractility
actuator with the positional precision and accuracy
charact~ristics of the liquid energized contractility
actuator.
Other a5pect5, f~atures and objects of the present
invention involve both methods and apparatus for control-ling
a plurality of such contractility actuators for articulating
an arm in a solid angle about a pivot point.
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6 DOCKET NO. 171~ 03
Still other advantages, objects, features and aspects
of the invented liguid energized contractility actuators
and systems utilizing ~uch actuators are more fully
described and will become apparent with reference to the
following descriptions and drawings of preferred and
exemplary embodiments of both the actuator and of systems
utilizing the invented actuator.
D~SCRIPTION OF THE DR~KINGS
Fig. 1 illustrates the essential components of a
"McKibben" type contractility mechanism.
Fig. 2 is a schematic of a rhombus responding to an
impressed force for illustrating an aspect of "McKibben"
type contractility actuators.
Fig. 3 is a simple vector diagram for illus~rating
the relative magnitude of the respective forces with respect
to an ideal rhombus.
Fig. 4 is a perspective schematic illustrating a
cylindrical segment of a "McKibben" type contractility
actuator.
Fig. 5 illustrates the constructor of a general
conical array beginning with a cone axi5 line AA and a cone
generation line BB line in a plane.
Fig. 6 is a ~chematic illustrating a "McKibben"
actuator in a relaxed configuration.
Fig. 7 is a 6chematic illustrating a t'McKibben"
contractility actuator in a contracted confi~uration.
1 308~ 1 8
7 DOCKET NO. 1717.03
Fig. 8 is a graph illustrating the cotangent
dependency of the contractile force generated by "McKibben"
type contractility actuators.
Fig. 9 is a graph illustrating the change in length as
a function as a change in volume for a "McKibben" type
contractile ~echanism and for a piston-cylinder contractile
mechanism.
Fig. 10 is a partial cut-away illustration of a
pivoting mechanism where invented liquid contracti1ity
actuators articulate platorms secured at either end of a
longitudinal arm.
Fig. 11 is an enlarged cross section of the coupling
~ecuring one end of the contractility actuators to the shank
of the longitudinal arm of the pivoting mechanism shown in
Fi~ure 10.
Figs. 12, 12a, and 12b illustrate the ~eatures of the
embodiment of the arm a~d platform shown in Figure 10.
Fig. 13 illustrates the essential features of another
embodiment for the arm and platforms of Fig. 10.
Figs. 14 and 15 present block diagrams of an exemplary
control system inflating and deflating contractility
actuators for articulating the respective platforms at the
distal ends of a pivoting mechanism of the type shown in
Figure 10.
Fig. 16 presents a schematic dia~ram of a plurallty of
pivoting mechanisms of the type illustrated in Fig. 10.
1,308'21~
8 DOCKET NO. 171~.03
DESCRIPTION OF PRæFERR~D AND EXEMPLARY ~MBODIM~NT5
As shown in Fig. 1 the basic "McKibben" type fluid
contractile actuator includes a cylindrical sheath 11 formed
from a flexible mesh 12 secured to connectors 13 at either
end of the sheath 11. A bladder 14 composed of a strong
~xpandable material is disposed within the sheath 11.
~onnected to the bladder i8 an inflation line 16 through
which a pressurizing ~luid 17 may be introduced for purpose
of expanding the bladder 14 within the cylindrical sheath
11. Appropriate valves 18 on the inflation line 16 direct
fluid from a pressurizing source 1~ into the bladder for
inflation (oontraction) and allow fluid to escape from the
bladderfor deflation (extension~.
In operation, the "McKibben" type fluidic
contractility actuator or "muscle" is connected between two
fixed points using connector 13 with the bladder 14
deflated. Ideally the cylindrical sheath formed from the
flexible mesh when connected between two flexible points
should experience a very slight tensile stress in order to
ensure that the sheath 11 when connected in its extended
"relaxed" position between the two points is at a minimum
diameter. The in~lation line 16 is then connected to the
source of pressurizing ~luid 1~. m e fluid may be
compressible, i.e., a gas, or incompressible, i.e., a
liquid. The fluid when introduced into the bladder 14
expands it against the enclosing mesh sheath 11 causing it
to expand diametrically and contract longitudinally
generating an extremely large contractile force between the
connectors ~3.
The two dimensional diagram of Fig. 2 illustrates the
basic principles of a "McKibben" muscle. In particular,
rhombu~ 21 is defined by four inextensible seyments or rods
1 3082 1 8
3 DOCKET NO. 1~1~.03
22 each having a length L. The ends of the segments 22 are
pivotally secured together allowing the adjacent segments to
rotate relative to one another. In the extended position,
the rhombus 21 has an initial half angle eO between the
respective segments as shown. If a force is impressed in
the vertical direction (along the Y-axis) the rhombus 21 is
disturbed increasing ~ts diagonal width along the Y axis and
decreasing its diagonal width along the X axis according to
a differential relationship:
dx = dy cotan ~;
where 0 is the half angle of ~he disturbed rhombus (shown
in phantom in Fig. 2).
As illustrated in Figure 2, the pivot points 23
between the segments 22 of the rhombus are not fixed. Now
assume that the pivot points 23 lying along the X-axis of
Fig. 2 are fixed, and using vector analysis, the magnitude
of the contractile force between those two pivot points
resulting when a force is impressed in the Y direction can
be determined. In particular referring to Figures 2 & 3, a
relatively small magnitude force Fy along the Y-axis can
generate a relatively large magnitude contractile force Fx
along the X-axis between the fixed pivot points of the
rhombus 21, particularly for small half-angles e. The
ratio of the contractile force along the X axis, Fx to that
of the force impressed in the Y direction, Fy varies as a
cotangent of the half angle 3 between the connected
segments 22, i.e.;
Fx = Py cotan e
Fig. 8 illustrates the magnitude of the force
magnification factor as the half angle e approaches O.
Now consider a three-dimensional connected network of
rhombi 21 in the form of right cylinder 24, a segment of
1 30~ 1 8
DOC~ET NO. 1717.03
which is illustrated in Fig. 4. Each rhombus 21 is formed
o~ ~our inextensible segments 22 pivotally coupled together
at their respective ends. The inextensible segments 22 of
the rhombi laterally combined to form a mesh of the
lnextensible helical cords which terminate at the respective
ends of the cylindri~al sheath formed by the rhombi.
Similarly, the sum of the respective diagonai widths of the
rhombi along the Y axis will equal the circumference of the
cylindrical sheath and the sum of the diagonal length of the
rhombi along the X axi5 will equal the length of the
cylindrical sheath. More generally, the right cylinder of
Fig. 4 can be supplanted by a general array formed b~ a
connected network of rhombi or other quadrilaterals as shown
in Fig. 5.
In particular, as shown in Fig. 5, two smooth
curvilinear lines AA and BB lie in substantially in a plane
P. Assuming that the lines AA and BB do not intersect, then
line AA can be designated as an axis and the line BB can be
connoted the generator of a conical array. For each point
on line AA construct a line segment La perpendicular to AA
within the plane P. The line segment La terminates at its
intersection with the generator line BB at a point Ba~
distance Pa from point a on the axis line M . Now rotate
the line segment La about the point a in a plane containing
it and perpendicular to the plane P. The locus of the end
points of the rotated line segment La defines a circle Ca
with its ceDter at a and havi~g a radius Pa. The locus of
points Ca for al~ points a on th~ axis AA defines a eneral
conical arrav which is a 2-dimensional surface that includes
~ost or all of the cone generator BB for a.
For any point, a on M , the circle CA i5 called a
circumference line for the array. It should be appreciated
that utilizin~ generally descriptive terms for describing
1308218
11 DOCKET NO. 1~1~.03
the sheath 11 enclosing the bladder 14 allows for
mathematical analysis of changes in configuration of th~
rhomboidal array as the sheath expands.
In particular, referring now to Figs. 6 and 7, a
general conical array 26 is shown in a relaxed or collapsed
configuration (Fig. 6), and in ~ contracted or inflated
configuration (Fig. 7). ~ith reference to the diagrams
presented in Figs. 6 and ~, the following definitions may be
utilized for the purpose of gaining an analytical insight a5
to how a "McKibben" muscle operates:
St is the parabolic length of the conical array;
Li is the relaxed length of the actuator between the
termination points;
Lf is a contracted length of the actuator between the
termination points;
Df is the maximum diameter of the array in the
contracted position;
Di is the minimal diameter of the conical array in the
relaxed configuration;
Vf i5 the internal volume of the conical array in the
contracted configuration;
Vi is the i~ternal volume of the conical array in the
relaxed configuration;
TH is the horizontal tension along the axis of the
conical array;
P is the f~uid pressure within the bladder;
D is the average diameter assumed equal to 2/3 (Di +
Df); and
R e~uals (~f - Di3/Lf
(The horizontal f~rce component due to pressurization
of the bladder within the general conical array is assumed
to be O predicated on an assumption of symmetry.)
1 30~1 8
12 DOCKET N0. 171~.03
Based on the above assumptions and definitions, the
~ollowing equations approximately describe the response of a
"Mc~ibben" muscle assuming that the materlal composing the
general conical array is inextensible:
st= Li= Lf[l+(2/3)R2-(2/5~R4~(4/7)R6 - ...]; (eq.l)
Vf - ( /15)Lf[2D2f+VfDi~(3/4)D2i]; (eq.2)
Vi = ( /4)D2iLi; (e~-3)
T = ( /6)(PLf2)[(Di~Df~/Df-D~ /2) PDLf(cotan e); (eq.4)
L~ - [l-(cosarcsiD(Di/2)-cosarcsin(Dj/2))]2/3[Li]; (eq.5)
The above equations illustrate the magnitude of the
horizontal contractile tensile force that can be generated
by a "McKibben Muscle." For example, from equation 4 it can
be ~een that the contractile force component due to the
pressurizing fluid theoretically increases asymptot~cally
approaching infinity as e approaches 0. (See the graph of
Fig. 8.)
The graph presented in Fig. 9 plots the change in
length of a McKibben Muæcle, ~L, along the horizontal axis
for a corresponding change in volume, ~V, along the vertical
axis based upvn the relationship obtained using a 5/8 in. HD
EXPANDO cylindrical he}ical weave sheath ~anufactured by
Bently Harris Corporation.
The solid line presents data points for a sheath
having a initial l~ngth Li of 9~76 in. The dashed line
presents data points for a sheath having a initial len~t~ Li
of 9.20 in. The third line presents the same data $or a
cylinder hRving an internal diameter of 1.125 in. and an
initial length Li of 10 in.
1 30~2 1 8
13 DOC~ET NO. 1717.03
From Fig. 9, it can be seen that for that particular
"Mckibben Muscle", the ratio of the rate of changP in length
to the rate of change of volume, ~L/~V, is substantial less
than the same ratio for a comparable cylinder (by a factor
of 4)-
It can also be observed from the relationshipsexpressed in ~quations 1-5 and from the graphs of Figures 8
and 9 that the spring constant of a "McKibben Muscle" has a
significant dependanc~ on the natur~ of the fluid inflating
the bladder 14. In particular, w~ere a ~as i5 utilized to
inflate the internal bladder 14, a "McKibben Muscle" is
highly ela.~tic with a correspondingly low spring constant
since a gas is compressible, and accordingly does not have
the capacity to maintain a reference position under
conditions of varying load. However, using an incompressible
fluid or a liquid to inflate the internal bladder 14
converts the "McKibben Muscle" into an inelastic contractile
mechanism having a correspondingly high spring constant
which accordingly has the capacity to establish and maintain
a reference position under conditions of varying load in
addition to capacity for generating contractile forces of
very high magnitude.
Turning now to Fig. 10, a pivoting mechanism 39
includes plurality of "McKibben" type contractile actuators
~1 each with one end secured by a coupler 42 to a shank of a
longitudinal arm 43 and its remaining end secured by an
eyelet fastener 64 to an articulating platform 44 by U-bolts
46. The platforms 44 each include a hemispherical socket 4~
receiving a spherical head at the distal ends of the ar~ 43.
In the p*rspectiv~ illustrated, the contractile ~ctuator
41A i~ contracted while contractile actuator 4~B ls
extended. A contractile actuator is also secured be~ween a
coupling point 45 on the arm 43 and the platform ~4 [not
'` ? 1 8
14 DOCKET NO. 1717.03
shown). Liquid is introduced into the respective contractile
actuators 41 via inlet ports 49 which connect to conduits 50
(not shown) communicating through the interior of the arm 43
and up through a central shaft 51 at each coupling point 45
on the shank of the longitudinal arm 43.
In more detail, referring to Fig. 11 the coupler 42
includes a central housing 54 with cylindrical passageway 56
dimensioned to a receive the shaft 51 integrally extending
out of the shank of the arm 43. The liquid sonduit 50
through the interior of the arm 43 and through the shaft 51
at each coupling point 45 communicates with an annular
plenum 57 cut radially into the passageway 56. A threaded
tube 58 forming the mouth of the bladder 14 screws into a
threaded port 52 communicating through the housing 54 to the
plenum 57. Liquid flows via the passageway 50 and plenum 5~
and out the outlet port 52 for inflating or expanding the
bladderl4. Suitable seals 61 are compressed between the
annular shoulders 62 on either side of the houslng 54 and a
mounting nut 63 and a corresponding annular ~houlder of the
shaft 51. The mounting nut 63 and the shaft 51 are suitably
threaded for compressing the seals 61 to render the coupling
42 liquid tight.
The mechanism illustrated in Fig. 11 for introducing
liquid into bladders 14 for inflating the actuators 41 is
exemplary. In fact, provlded there is sufficient space
between the quadrilateral segments forming the mesh sheath
11, the connection to the bladder 14 can be made through a
nozzle communicating to the interior of the bladder
extending centrally between the quadrilateral mesh 6egm~nts
forming the sheath.
1 3()P,~ 1 ~
DOCKET NO. 171~.03
In the preferred ~mbodiment, again referring to Fig.
11, each strand 66 of the mesh sheath 11 forms a closed loop
which encircles both the eyelet fastener 64 and the coupler
42 In this fashion, any limitation on the magnitude of the
tensile load which can be born by the actuator 41 ls
determined by the strengths of the strands 66, the shaft 51
and the U-bolts 46. In fact, the primary criteria for
selecting a mechanism or means for coupling the mesh sheath
11 to the eyelet ~astener 64 and coupler 42 is that it must
be able to withstand the maximum e~pect~d tensile load
between the connection points of the actuator 41.
Referring back to Fig. 10, the platform 44 pivoted by
the actuators 41 about the spherical heads 48 at either end
of the arm 43 each include connector means 67 (at the top)
and 68 ~at the bottom). The connectors 67 and 68 simply
define receiving receptacles 69 for receiving
correspondingly shaped male or female protrusions or
receptacles ~not shown) dimensioned to receive the
connectors 6~ & 68. Accordingly, the pivoting mechanism 3g
can be secured to a stationary surface or the pivoting
platform 44 of an adjacent plvoting mechanism 39. (See
Figure 16.) As illustrated, the connector 68 is inclined
with respect to the longitudinal axis o~ the arm 43 to
provide an additional dimension to the articulating range
and capacity of a machine formed by two or more pivoting
mechanisms 39.
The actuators 41 w~rk in opposition as illustrated by
actuators 41A and ~lB ( Fi~. 10). Referring to Figures 12,
12A & 12B each arm 43 lncludes four (4) contractile
actuators 41, for articulating the top platform 44A and ~our
(4) for articulating the bottom platform 44B. The
re p~ctive fastening positions of the actuators articulating
the top platform 44, indicated by the U-bolts 46 in Figure
12A, are rotated 4~ degrees with respect to the coupling
1 30~2~ ~
16 DOCKET NO . 1717.03
points 45 on the shank of the arm 43 of the actuator.s 41
articu~ating the bottom platform 44b. Similarly with
reference to Figure 12B, the U-bolts 46 securing the eyelet
fasteners 64 of the latter actuators 41 to the bottom
platform are rotated at an angle of 45 degrees with respect
to the coupling points 45 of the former actuators 41
articulating the upper platform 44A.
As illustrated in Figures 12 the articulating
mechanism formed by the co~bination of the arm 43, the
platforms 44 A ~ B and the contractil~ actuators 41 (Figure
10) can tilt a particular platform through a solid angle of
approximat~ly 90 degrees as illus~rated in phantom ~or the
top platform 44 A in Figure 12. Such tilting of the
platform 44 is accomplished by relative contraction of the
respective actuators articulating a particular platform. In
the example illustrated in Figures 10, 12, 12A and 12B,
contraction of a particular actuator tilts the particular
platform in a plane determined by the positional
relationship of the U-bolt receiving the eyelet fastener 6~
of the particular actuator 41 and its coupling point45 on
the shank of the arm 43.
As illustrated in Figures 12A and 12B. The U-bolts 46
of the platform and coupling points 45 on the arm 43 are
oriented in the same plane. It should be appreciated
however, that the platform 44 can rotate relative to the arm
43 such that contraction of a particular actuator secured
between its coupling point 45 on the arm 43 and the U-bolt
46 of the platform 44 provides a twisting or torque ~oment
in addition to tilting the platform.
Figure 13 schematically illustrates the relationship
between fastening points ~1 on a platform 72 and coupling
po~nts ~3 on the shaft 74 of an embodiment of a pivotin~
mechanism ~O ~or three contractile actuators (not ~hown).
Such f astening points 71 on the platform 72 and coupling
1 30~2 1 ~3
17 DOCKET NO. 1717.03
points 73 on the shaft 74 for the platform 72 at the other
end are rotated ~O degrees with respect to each other.
Again, a cylindrical head indicated at 76 is received in a
corresponding socket is (not shown) on the platform, and it
should be realized that the platform 72 can be rotated such
that a contracting actuator imparts a twisting as well as a
tilting moment to the platform as it contracts.
Referring now to Figure 14, a control system for
controlling an articulating or pivoting mechanism ~O of the
type depicted in Figure 10, ~hould include a master control
system (section A) which may comprise a computer or other
type of programmable data processor system. The master
control system inputs commands and r~ceives data via
address bus 81, a data bus 82, and a control signal bus 83.
The control system should also include a work station
controller (section B) for implementing subprograms unique
to particular articulating mechanisms for accomplishing such
tasks as parts handling, tool manipulation, measurement and
the like. The work station basically insludes a micro-
controller 84 which accepts commands from the master control
and contains memory and microprograming for implementing
device-level action. The work station should also include
an energizing source such as pump 85 and manifold gl for
inflating the contractlle actuators making up the system
with a suitable high pressure liquid (water or hydraulic
oil).
At the device level (section C~ control processing is
provided via an address decoder B6 for interpretin~ signals
directed to a particular articulating mechanism, and a data
multiplexing system for interpreting directional data coming
~rom the micro-controller 84. A read only memory IROM) and
a data latch indicated at 8B, the heart of the device level
oontrol processing subqystem, ~ets the sub-routines for
opening an~ closin~ valves psr instructions from either or
1 3(~8~ 1 8
18 DOCKET NO. 1~17.03
both the master control and micro-controller 84 subsystems
to inflate or deflate a particular artiçulating mechanis~
(section D).
In particular, an amplifier 89 receives and amplifies
output signals from the ROM/data latch 88 opening and
closing hiyh speed valves 90: i.) controlling flow of a
liquid Prom the high pressure side of the manifold 91 into
line(s) for inflating particular contractile actuator(s)
inducing contraction and il.~ controlling flow of the liquid
from line~s) into the low pressure side of the manifold 91
for deflating particular contractile actuator(s) allowing
extension.
At the articulating mechanism (section D), feedback
signal generators 92 receiving input from pressure sensors
94 located between the valves 90 and the contractile
actuators 95 and from one or more relative
motion/displacement sensors 93 located on an articulating
structure 96 provide data signals to both the master control
and work station contol subsystems indicative of
displacement relative to contraction and extension of the
respective contractile actuators 95.
Figure 15 presents a block diagram schematically
illustrating a simple control circuit (Fig. 14, section C)
for controlling two contractile actuators wor~ing in
opposition including an address decoder 101, and a data
latch 102. The data latch 102 receives inpu~ from the
micro-controller 84, and the master control subsystems via a
data bus (the address bus 81, data bus 82 and control
8ignal bus 83 of Fig. 14) and a clocking pulse from a clock
97. The data latch 102 outputs signals directed .Por
particular values. ~n amplifier 103 receiv~s the output
from the data latch 102 and amplifys it for ~witching
(opening and closlng) ~olenoid, diaphragm and/or shaped~
memory-alloy actuated high speed valves 90. Suitable valves
1 30~2 1 ~
l9 DOCKET NO. 171~.03
include Model 8225 made BY AUTOMATIC SWITCH VALVE CO. (ASCO)
Florham Park, New Jersey, and Model Nos. EV2-12 and ETO-3
made by CLIPPARD Cincinnati, Ohio.
Although the preferred and exemplary embodiments of
the invented liquid inflated contractility actuator and
systems for utilizing same are described in context of
representative, schematic, and computational embodiments,
many variations and modifications of the invention including
those suggestcd by the computational and schematic models
utilized for describing and understanding the invention
maybe made without departing from ~he scope of the invention
as defined and set forth in the following claims
~e clain:
