CA1280785C - Method and system employing strings of opposed air- inflatable tension actuators in jointed arms, legs, beams and columns for controlling theirmovements - Google Patents
Method and system employing strings of opposed air- inflatable tension actuators in jointed arms, legs, beams and columns for controlling theirmovementsInfo
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- CA1280785C CA1280785C CA 529523 CA529523A CA1280785C CA 1280785 C CA1280785 C CA 1280785C CA 529523 CA529523 CA 529523 CA 529523 A CA529523 A CA 529523A CA 1280785 C CA1280785 C CA 1280785C
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Abstract
985.006-CANADA
GKP
S P E C I F I C A T I O N
METHOD AND SYSTEM EMPLOYING STRINGS OF OPPOSED AIR-INFLATABLE
TENSION ACTUATORS IN JOINTED ARMS, LEGS, BEAMS and COLUMNS
FOR CONTROLLING THEIR MOVEMENTS
Inventor : Henry M. Paynter ABSTRACT OF THE DISCLOSURE
The method and system employ strings of tension actuator in opposed relationship for controlling motions or deflections of jointed members: for example, for controlling the motions of arms, legs and elephant trunks or flexible antennae in robots and for controlling the deflections of beams and columns in frames and structures. There opposed tension actuators are inflated with controlled air pressures which are oppositely varied from a predetermined common-mode pressure Po (initial fluid pressure level Po). In other words, as one tension actuator is being inflated with pressure increasing above Po, the opposed tension actuator is being inflated with pressure decreasing below Po for producing motion or deflection of the jointed member in one direction, and conversely for producing motion or deflection in the other direction. The opposed tension actuators have their ends anchored to rigid movable plates or struts containing sockets for the respective joints. By virtue of controlling the opposed actuators with a common-mode pressure level Po, their are always exerting a net compressive force on each joint, so advantageously permitting usage of simple, inexpensive, light-weight, non-capturing joints as shown. Moreover, the jointed member automatically returns to a predetermined mid-range rest position whenever air pressures are returned to Po.
A nearly uniform stiffness (or mechanical output impedance) is provided at all positions by controlling the opposed pressures to be Po + .DELTA.P and Po -.DELTA.P, where .DELTA.P is a corresponding incre-ment above and below the initial (common-mode) level Po. In this way, precision open-loop proportional control is achieved.
GKP
S P E C I F I C A T I O N
METHOD AND SYSTEM EMPLOYING STRINGS OF OPPOSED AIR-INFLATABLE
TENSION ACTUATORS IN JOINTED ARMS, LEGS, BEAMS and COLUMNS
FOR CONTROLLING THEIR MOVEMENTS
Inventor : Henry M. Paynter ABSTRACT OF THE DISCLOSURE
The method and system employ strings of tension actuator in opposed relationship for controlling motions or deflections of jointed members: for example, for controlling the motions of arms, legs and elephant trunks or flexible antennae in robots and for controlling the deflections of beams and columns in frames and structures. There opposed tension actuators are inflated with controlled air pressures which are oppositely varied from a predetermined common-mode pressure Po (initial fluid pressure level Po). In other words, as one tension actuator is being inflated with pressure increasing above Po, the opposed tension actuator is being inflated with pressure decreasing below Po for producing motion or deflection of the jointed member in one direction, and conversely for producing motion or deflection in the other direction. The opposed tension actuators have their ends anchored to rigid movable plates or struts containing sockets for the respective joints. By virtue of controlling the opposed actuators with a common-mode pressure level Po, their are always exerting a net compressive force on each joint, so advantageously permitting usage of simple, inexpensive, light-weight, non-capturing joints as shown. Moreover, the jointed member automatically returns to a predetermined mid-range rest position whenever air pressures are returned to Po.
A nearly uniform stiffness (or mechanical output impedance) is provided at all positions by controlling the opposed pressures to be Po + .DELTA.P and Po -.DELTA.P, where .DELTA.P is a corresponding incre-ment above and below the initial (common-mode) level Po. In this way, precision open-loop proportional control is achieved.
Description
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FIELD pF THE INVENTION
The present invention is in the field of air-inElatable tension actuators which decrease in length as they are inflated and conversely which elongate as they are deflated, for example as shown in U.S. Patent No. 3,645,173 of John M. Yarlott, and as shown in my U.S. Patent No. 4,751,8~9 issued June 21, 1988. More particularly, this invention relates to a method and system employing elongated strings of such pneumatic tension actuators arranged and operated in opposed relationship in jointed arms, legs, beams and columns for controlling their movements, Eor example for controlling the movements of arms, legs, elephant trunks or flexible antennae in robots and for controlling the deflections of beams and columns in frames and structures.
BACKGROUND OF THE DISCLOSURE
Small-size robots performing precise but rapid light assembly tasks, have often utilized electric and/or hydraulic drive operators. The mass and weight of such conventional operators have tended to limit the dynamic response of prior robots and to dominate the total cost of such robots.
SUMMARY OF THE DISCLOSURE
The present invention provides a method and a system, wherein pneumatic tension actuators are interconnect~d in s~ries to form strings arranged for controLling elongated jointed arms and the like. Such strings of tension actuators extend along opposite sides of the elongated jointed arms and they act in opposition to each other for controlling its motions or deflections.
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The term "el~ngated jointed arm" i~ intended to be interpreted broadly to include various types o~ elongated jointec members, for example such as arms, legs, ele~hant trunks, flexible antennae, and the like, in robots and including beams and columns in chasses and carriages, all haviny a plurality of joints, with the joints being located at spaced p~sitions along the length of the jointed member.
The opposed tension actuators are inflated with con-trolled air pressures which are oppositely varied from a prede-termined common-mode pressure PO (initial fluid pressure level PO). In other words, as one string of tension actuators is beinc inflated with pressure increasing above PO, the opposed string is ~upplied with pressure decreasing below PO, for producing motion or deflection of the jointed arm in one direction, and conversely for producing motion or deflection in the other direc-tion~ The jointed arm includes elongated links arranyed in sequence in end-to-end relationship along the length or longi-tudinal axis of the arm. The first link in sequence is position-ed near a supporting structure or support body, for example such as the body of a robot, and has a pivotal mounting to this sup-port body, and the last link in the sequence is positioned and rigidly attached near the remote (or outer) end of the arm. Each successive link in the sequence has a single pivotal mounting to the preceding link for enabling the arm to bend and swing into various angular positions. Thus, the arm can curve or straighter , can swing up or down.
Fastened rigidly to the above-described rigid links, thexe are rigid elements for controlling the movements of the arm, with a respective one of these rigid elements being located at each pivotal mounting and projecting out on opposite sides of the longitudinal axis of the arm. The strings of pneumatic ~.ZE3~'78~
tension actuat~rs which h~ve been de~cribed ~8 extending along opposite sides of the jointed arm are off6et from, i.e. ~paced away from, the longitudinal axis of the arm. These ~trings are fastened to the respective rigid elements at fastening positions which are located at points located between tension actuators in the respective strings.
A controllable source of pressurized air communicates with the first tension actuator in each of the respective strings for controllably inflating the strings on opposite sides of the arm for producing arm motion, like muscles in the arm. By virtue of controlling the opposed strings of actuators with a common-mode pressure level PO, they are always exerting a net compress-ive force on each pivotal mounting, i.e. each joint, so advantageously permitting usage of simple, inexpensive, light-weight, non-capturing joints as shown. Moreover, the use of a common-mode pressure automatically causes the jointed arm to return to a prPdetermined mid-range rest position whenever air pressures are returned to PO. A nearly uniform stiffness (or mechanical output impedance) is provided at all arm positions by controlling the opposed pressures to be PO ~ ~ P and PO - ~P, where ~ P is a correspondin~ increment above and below the initial (common-mode) level PO.
The terms "air" and "pneumatic" and "gaseous fluid"
are intended to be interpreted broadly to include the various appropriate gaseous media capable of being economically employed to inflate tension actuators, for example air, mixtures of gases or individual gases, nitrogen, carbon dioxide, and the like.
In accordance with the present invention in one of its embodiments there is provided a gaseous-fluid-pressure actuated, elongated jointed arm having a longitudinal axis and ~L28~
capable Df being moved about in variou~ controlled directions, comprising: a plurality of rigid elements located at re~pective positions spaced along the axis of the arm, each o these elements extending across the axis and having first and cecond projections protruding outwardly on opposite sides of the axis, all of the first projections being on a first side of said axis and all of the 6econd projections being on the second ~ide of said axis. Each of these elements is oriented generally perpendicular to the neighboring portion of the longitudinal axis at the respective position where the element crosses the axis. mere are a plurality of elongated rigid links extending longitudinally along the axis, with respective ones of these links extending along the axis between successive elements, and with one end of each link having a pivoted relationship with the adjacent element. There are first and second pluralities of fluid-inflatable tension actuators, and each of these tension actuators has an inlet end and an outlet end. The tension actuators of the first plurality are joined end-to-end, forming a first inflatable string with the outlet end of each actuator communicating with the inlet end of the next actuator in the first string, and with the outlet end of the last actuator in the first string being blocked. The tension actuators of the second plurality are joined end-to-end forming a second inflatable string with the outlet end of each actuator communicating with the inlet end of the next actuator in the second string, and with the outlet end of the last actuator in the second string being blocked. The first string of tension actuators extends generally parallel with the axis of the arm and is offset f~om the axis on the first side of the axis, while the second string of tension actuators extends generally parallel with the axis and is offset from the axis on the second side thereof. The 1 ~28~17~
fir~t string cf tension actuatsr6 is anchored t~ the fir6t projection~ of said elements, with respective anchoring connections bein~ located at the ends of tension actuators in said first string, and the ~econd string of tension actuators is anchored to the ~econd projecti~ns of 6aid elements with each respective anchoring connection being located at the ends of tension actuators in the second string. Pressurized gaseous fluid control means communicate with the inlet ends of the first and second strings for controllably inflating these ~rings with pressurized fluid controllably varying in opposite directions from a common pressure level PO for causing the jointed arm to move and bend in various directions.
BRIEF DESCRIPTION OF THE DRAWINGS
The various features, objects, aspects and advantages of the present invention will become more fully understood from a consiaeration of the following-detailed description in conjunction with the accompanying drawings, which are not drawn to scale but are arranged for clarity of illustration.
In these drawings:
FIGURE 1 is a longitudinal sectional view of a jointed arm including a plurality of strings of air-inflated tension actuators acting in opposition to each other for producing controlled movements through controlled curvature and bending of the arm. FIG. 1 is a section taken along the line 1-1 in FIG. 2.
FIG. 2 is a cross-sectional view of the jointed arm of FIG. 1, being a section taken along the plane 2-2 in FIG. 1.
FIG. 3 is a schematic diagram of a controllable source oi pressurized gaseous fluid, for example air at various pressures for controlling contraction and elongation of the -G-~2~
strlng~ oi ten~ion a~tuator6. For ~larity ~ ~llu~trati~n, electrical re~istance 6ymbol6 and variable re~i~tance 6ymbol6 are shown in ~IG. 3 for explaining oper~tion o~ the control-lable air source.
~ IG. 4 is an enlargement of a portion of the dia-gram of FIG. 3 in which mechanical ~ymbol~ replace the electrical symbols for further explanation of the illustrative embodiments, and showing the control system.
~ IG. ~ illustrates movement of the various embodiments of the jointed arm shown in FIGS. 1-4 and in ~IGS. 6-12.
FIG. 6 is an enlargement of a portion of FIG. 1 included within the dashed and dotted circle for illustratin~
one embodiment of the pivotal joints in the arm.
FIG. 7 is a view similar to FIG. 6 and illustrating another embodiment of the pivotal joints in the arm.
FIG. 8 is a longitudinal sectional view of a portion of a jointe~
arm similar to FIG. 1, except that the pivotal joints have line contact, and therefore they act like hinges for allowing swinging movement of the arm back and forth along predetermined arcs of movement in a predetermined plane.
FIG. 9 is a cross-sectional view of the jointed arm of FIG. 8, being a section taken along the plane 9-9 in FIG. 8.
FIG. 10 is a perspective view of one of the links of the arm of FIGS. 8 and 9.
FIG. 11 illustrates a further embodiment of a pivotal joint for use in the arm of FIGS. 8 and 9.
FIG. 12 is a perspective view of the type of link used with the joints of FIG. 11.
FIG. 13 shows a further embodiment of an elongated jointed arm operated by opposed pairs of pneumatic tension actuators.
FIG. 1~ is an enlarged sectional view showiny the I couplings between successive tension actuators in a jointed arm.
~ IG. 15 is an enlarged ~ectional view showing in greater detail the ball-and-socket pivotal joint corre~ponding to the embodiment depicted in FIG. 5.
FIG. 16 illustrates a further embodiment of the compression-carrying link in the form of a compression element constructed as a pressurized chamber sealed by a fiber-rein-forced elastomeric oblate surface of revolution.
~ IG. 17 shows in cross section yet another embodiment of the compression element in the form of a pres-surized flexible annular shell, shaped like a laterally-compressed tire inner-tube.
FIG. 18 depicts an advantageous embodiment of my invention wherein the compressive load is carried by a pres-surized cell formed by an air-tight membrane envelope extend-ing between rigid circular end-plates and completely enclosing the tension actuators contained within.
FIG. 19 shows a cross-sectional view of the jointed-arm embodiment illustrated in FIG. 18, being a section taken along the plane A-A of FIG. 18.
FIG. 20 represents a longitudinal interior view of the same jointed-arm embodiment shown in FIGS. 18 and 19, being a cross section taken along the plane B-B of FIG. 19.
FIG. 21 indicates the variation in curvature and resulting movement of a multi-section embodiment as the control pressures are varied.
FIG. 22 shows a useful embodiment employing two jointed-arm sections terminating in a gripper, all of which have independent open-loop control.
FIG. 23 graphs the proportional variation in tension actuator spring-rate with actuator supply pressure.
FIG. 24 indicates quantitatively how the push-pull operation of the opposed actuator strings yields open-loop proportional con-trol of arm curvature as portrayed in FIGS. 5, 21 and 22.
~ ~8078~
DETAIL~D DESCRIPTI~N OP PRE~ERRED EMB~DIM~N~S
Inviting attention to ~IGS. 1 ~nd 2, there is ~hown an elongated jointed arm 20 having an inner end 21 and an outer or remote end 22. The inner end 21 of the arm i~ mounted upon a support 24, for example such as the body of a robot having a ~ase or frame 26. A controllable source 30 of pressurized gaseous fluid located near the support 24 serves to control the arm motions, as will be explained later. The outer end 22 of the arm 20 is shown carrying an article-handling mechanism 40 for grasping, handling or manipulating objects or articles, as will be explained later.
In lieu of this article-handling mechanism 40, the outer end of the elongated jointed member 20 may carry any suit-able termination, for example in the case vf a jointed leg, a termination such as a friction foot is used with a wear-resistant sole for engaging the floor or the ground; in the case of a jointed antenna or elephant trunk, the termination 40 includes a suitable sensor, which may be a mechanical proxi-mity or contact or shape sensor or shape tracer; the sensor may be an optical, thermal, magnetic, electrical or radiation sensor. The teimination 40 may be a suitable tool, for example such as a paintspray gun, weldiny tool or grasping or mani-pulating tool, and this termination may comprise one or more sensors plus one or more tools in cooperative association with each other. In cases where the jointed member 10 is employed as a column or beam in a frame or structure, then the termination 40 is a mechanical fastening or coupling for attach-ing the outer end 22 of this column or beam to another frame member or structural element.
!
~ 8-Finally, the termination 40 may in turn comprise an extended additional sequence of elongated jointed-arms, like 20 itself, joined in various ways, and constructed with similar or different dimensions and controlled by a variety of supplied pressures. A particular embodiment with two arms, 20F and 20G is portrayed in FIG. 22.
In summary, the elongated jointed member 20 may carry any suitable termination means 40 or combinations thereof on its outer end 22, as appropriate for the instal-lation and usage of this jointed member 20 in various o~s -8~-I
Extending along the longitudinal axi6 ~f the arm 20 is a sequence of elongated rigid links 50-1, 50-2, ~0-3, 5~-(n-1) and 50-n, where "n" is the number of jointed sections in the arm 20. Each of these links 50 is formed of ~trong, lightweight material, for example aluminum or fiber-reinforced plastic, and each link is shown having the shape of a round rod, preferably of tubular configuration for minimizing weight, mass and inertia while maximizing rigidity, with conically pointed or tapered ends. It is noted that the links 50 can have any desired cross-sectional configuration for optimizing strength and rigidity for resisting deflection under axial compression, for example such as an extruded H-shape or star shape, or square rectangular, triangular or hexagonal shape, and so forth; and in each case, these links 50 are configured for maximizing strength and rigidity while minimizing weight, mass and inertia.
As shown most clearly in FIG. 6, the pointed or taperl ~d ends 52 of each link 50 are received in a centrally located socket indentation 54 ]o~ate~ ,7n, the adiacent face of a rigid, generally square (See FIG.2) plate element 60. As shown in FIG. 1, there are a plurality of these plate elements 60-1, 60-2, 60-(n-1) and 60-n, with each of these plate elements 60 being positioned between the adjacent pointed end of the successive links 50 along the length of the arm 20. The last plate element 60-n is located at the outer or remote end 22 of the arm and : carries the termination means 40. Thus, each link 50 has a pivotal mounting 52, 54, 60 at one of its end~.
FIG. 7 illustrates an alternative embodiment of the pivotal mountings at the ends of the respective links 50.
These ends 52 are rounded and are received in axially aligned socket indentations 54 located in opposite faces of the rigid plate elements 60.
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It is noted that regardless oE the specific shape of the tapered link ends 54, as seen in FIGS. 6 and 7, they are tapered inwardly toward the longitudinal arm axis 28 for causing the tip of each tapered end 52 to have a small area of contac-t with the center of each socket 5~, which is aligned with the axis 28 for defining and forming a pivot point 56. Moreover, the sockets 54 each flare outwardly away from the axis 28 for providing clearance for enabling the links 50 to move or swlng into various angular positions relative to these plate elements 60, as illu.strated in FIGS. 5 & 15, where ball and socket joints are indicated.
Each of the plate elements 60 is formed oE strong, lightweight material similar to that used to make the links 50 for the same reasons, as before, namely for minimizing weight, mass and inertia while maximizing strength and rigidity. It is noted that in order to reduce the weight and mass of the generally square plate elements 60 they may have cut-outs (not shown). Such cut-outs are not shown in FIG. 2 for clarity of illustration, and because the use of weight-reducing cut-outs is known for inclusion in lightweight but strong, rigid mechanical elements. In the embodiments indicated in FIGS. 16-20, 22, the end plates 60 are taken to be circular.
In order to produce controlled motion of the arm 20, there are four strings 70-1, 70-2, 70-3, and 70-~ (FIG. 2) of pneumatic, inflatable tension actuators 80. These tension actuators 80 are constructed as described and shown in U.S.
Patent No. 3,6~5,173 of ~ohn M. Yarlott, or as shown in U.S.
Patent No. ~,751,869. Such tension actuators 80 have the advantageous operating characteristic that inflation causes them to lncrease in their enc]osed cross-sectional area and volume while simultaneously decreasing (contracting) in their axial length. In other words, as they bulge, they contract in their axial length. Conversely, when ~ 7 -~ ~28~7~3~
such ten~icn ~ctu~t~rs ~re ~efl~ted, ~.e. ~ they become m~re ~lim, they elongate. The disclo6ures ~f these two referenceç
are incorporated herein by reference, and the reader i~ invite~
to read them to appreciate more fully the de~irable qualities of lightweight, low mass, quick respon6e, xeliability, long life, simplicity and economy, which are provided by cuch ten6ion actuators 80.
It i6 noted that these tension actuators 80 are 8ym-metrical end-to-end~ and they each include an inflatable, elastomeric bladder (envelope or impermeable skin) 81 with a pai of end fittings 82 and 83 attached to this elastomeric bladder at each end. These sleeve-like end fitting~ 82 and 33 define axial passages or ports 84 and 85, respectively, communicating with theinterior region 86 of the bladder 81 for enabling the bladder to be inflated or deflated. The two end fittings 82 and 83 in each tension actuator 80 are identical, and their axial passages or ports 84 and 85 are identical. However, for clarity of explanation, it is useful to describe that end fittin~
82 a,nd its passage or port 84 of each actuator that is located nearer to the controlled, pressurized air supply 30 as being the input end and input passage (input port), while that other end fitting 83 and its passage or port 85 that is farther from the controlled air supply 30 is described as being the outlet end ant outlet passage (outlet port). It will be understood that durin inflation of the respective actuator strings 70-1, 70-2, 70-3 and 70-4, air flows from the source 30 thr~ugh four respective air conduits or airlines 39-1, 39-2, 39-3 and 39-4 into the inPut end 82 of the first tension actuator of the respective actuator strings 70, and through the actuator interior region 86 and thence through its outlet end fitting 83 into the input end fitting 82 of the next successive actuator in the respective string 70, and so forth.
I
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~ hu , the 6tring6 70-1, 70-2, 70 3 and 70-4 of tensivn actuator~ 80 are formed by coupling ~ucce~sive tension actuators together in end-to-end relationship with the passage or port 85 in the outlet end fitting B3 of each actuator in the string communicating with the inlet passage or port 84 in the inlet end fitting 82 of the next successive tension actuator in the string. The outlet passage 85 in the last tension actuator 80 in each string 70 is plugged air-tight at 87.
The inflatable bladders 81 each includes longitudinally extending, relatively inextensible filaments or strands of stron~ ~, flexible high tensile strength material, for example 6uch as Xevlar plastic, polyester, or polypropylene, as described in detail in the references above. These longitudinal filaments or strands are attached to the tubular end fittings 82, 83 for causing these end fittings to be pulled toward each other as the ~ladder 81 is inflated for producing axial contraction of the tension actuator.
In order to control motions of the arm 20, the four actuator strings, in clockwise (FIG. 2) order around the arm axis 28, referenced as 70-1, 70-3, 70-2 and 70-4, are offset from the arm axis 28, as seen most clearly in FIG. 2, and they are uniformly spaced apart 90 around the axis 28, ~eing located near the four corners of the square plate elements 60.
The first actuator string 70-1 on a first side of the arm axis 28 operates in opposition to the second actuator string 70-2 spaced 180 away, namely, on the other or second side of the axis. Similarly, the third actuator string 70-3 on one side of the axis 28 operates in opposition to the fourth actuator string 70-4 spaced 180 away on the opposite side of the axis. In summary, these four actuator strings are operated as two opposed pairE~.
11 Z80 7~35 These actuator 6trings 70-1, 7D-3, 70-2 and 70-4 are fastened ~anchored) to the respective corner~ of the plate elements 60 by connecting the end fittings 82, 83 to apertures 62 in these plate elements. For example, the respective end fittings 82,83 are air-tight cemented or bonded in end-to-end relationship in the respective apertures 62. An alternative assembly procedure is to use screw-threaded coupling sleeves as in FIG. 14 for coupling together the respective end fittings 82, 83. Such coupling sleeves are fitted through the apertures 62 in the plate elements 60, shown in FIG. 14.
The gripping mechanism 40 is shown as including a bracket 41 secured to the outer face of the outer plate element 60-n. A pair of opposed gripping fingers or jaws 4Z are hinged to the bracket 41 by pivot pins 43. For opening and closing these grippers 42, there is a double-acting cylinde~
and piston assembly 44 having its piston rod 45 pivotally pinnec at 46 to one gripper 42. The cylinder has a mounting rod 47 pivotally pinned at 48 to the other gripper 42. A pair of flexible air lines 49 communicates with the cylinder 44 at opposite ends. Feeding pressurized air through one of the lin~ ~s 49 into one end of the cylinder 44 causes the grippers 42 to 128078~i close toward each other, and conversely to open when pressuriz ed air is fed through the other line into the other end of the cylinder 44. These flexible air lines 44 are strung through holes 64 ~FIG. 2~ in the plate elements 60 located near the arm axis 28. Air source 30 (FIG. 3) includes line 51 supplying regulated pressurized air to pneumatic controller 53 connected to air lines 49 for operating the article handler 40. There are electrical leads 55 connected from the control-ler 53 to a control panel 100 (FIG. 4) including a microprocessor for automatic operation of the article handler 40.
In FIG. 3 is shown the controlled pressurized air supply 30 comprising an intake air filter 31, communicating with ambient air and connected into an air compressor 3~, whose output passes through a moisture eliminator 33, and through a further filter 34 capable of removing fine particles rom the compressed air. From the output of filter 34 an air supply line 35 leads to a pressure regulator 38 whose regulated output feeds into two branches 36, 37 which feed into two pneumatic bridge networks 90-1 and 90-2, which are analogous to electrical Wheatstone bridges.
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Each bridge network 90 includes a pair of pressure-dropping flow resistors 92 and 93 and a pair of remotely con-trollable pressure-dropping flow resistors 94 and 95 whose out-lets are vented to atmosphere at 96.
As ~hown in FIG. 4, the pressure-dropping flow resist-ors 92 and 93 are manually adjustable valves each providing a flow-impeding orifice, for example needle valves. The remotely controllable pressure-dropping flow resistors 94 and 95 are needle valves which are controllably adjusted by electric actuator 97 and 98, re ~ ctively, for example solenoids or else reversible stepping mDt~ ~rs.
The output supply line 39-1 is connected to the bridge 90-1 at the juncture of components 92 and 94, while the second output supply line 39-2 is connected to the opposite side of this pneumatic bridge at the juncture of components 93 and 95. Similarly, the third and fourth output supply lines 39-3 and 39-4 are connected to the respective corresponding junctures located on opposite sides of the other pneumatic bridge 90-2.
Consequently, the pressures of the air being fed through the four respective output supply lines 39-1 39 2, 39-3 and 39-4 are controlled by varying the settings of the needle valves 94 and 95 in the two pneumatic bridges 90-1 and 90-2~
The operation of these two pneumatic bridges 90-1 and 90-2 will now be explained. The pressure regulator 38 is set to supply a regulated air pressure of 2Po through the two branch lines 36 and 37 into the input junctione 99 of the two bridges ~L280~78~i 90-1 and 90-2. The four pressure-dropping flow resisting com-ponents 92, 93, 94 and 95 in each bridge are all initially 6et the ~ame. Con~equently, one-half of the pre~sure drop occurring from the input junction 99 to the vent 96 will take place in the components 92 and 93, and the other half of the pressure drop will take place in the components 94 and 95. The result is that the initial output pressure in all four of the output supply lines 39-1, 39-2, 39-3 and 39-4 will be the same, namely, one-half of the input pressure of 2Po. Thus, the initial pressure in lines 39-1, 39-Z, 39-3 and 39-4 is PO' which is called the initial supply pressure level.
This initial ~upply pressure level of PO may be at any desired gage pressure, where atmospheric pressure is taken as zero p.s.i. gage, in the range from 3 p.s.i.g. up to 120 p.s.i.g. depending upon the burst strength limit of the individu~ ll tension actuators 80.
When the pressure-dropping flow resistance of the component 94 in the bridge 90-1 i5 increased from its initial value, more than one-half of the total pressure drop occurring from the input junction 99 to the vent 96 now occurs across this component 94. Consequently, the pressure now appearing in the output line 39-1 is greater than PO. The larger the pressure drop occurring in the component 94, the nearer the pressure in the output line 39-1 approaches the 2Po regulated pressure level at the input junction 99.
Conversely, when the pressure-dropping flow resistan ce of the component 94 in the bridge 90-1 is decreased from its initial value, less than one-half of the total pressure drop now occurs across this component 94. Thus, the pressure now appearing in the output line 39-1 is less than PO. The smaller ~ 8~)'78S
the pressure drop occurring ~n the component 94, the nearer the pressure in the output line 39-1 approaches the ~ero gage pressure of the atmospheric vent 96.
The motors 97 and 98 are connected for adjusting the components 94 and 9S in a bridge 90 in opposite directions.
Consequently, the output pressures appearing in the two output lines 39-1 and 39-2 ~and also in the two output lines 39-3 and 39-4) vary in opposite directions from the initial pressure level PO. Preferably these controllable pressure-dropping components 94 and 95 are arranged to produce equal and opposite incrementc ~P above and below the initial pressure level P; so that the pressures in the two output lines 39-l and 39-2 (and also in the two output lines 39-3 and 39-4) have values of PO + ~ P.
A nearly uniform stiffnessor mechanical output impedance of the motions of the arm 20 is advantageously obtained by controlling the pressures in the bridge output lines 39-l and 39-2 (and also in the other bridge output lines 39-3 and 39-4) to vary by equal increments ~ P in opposite directions from the initial common-mode pressure level PO. Moreover, by controlling the opposed actuator strings with a common mode pressure level PO , these actuator strings are always exerting a net compressive force on each joint, so advantageously permitting usage of simple , inexpensive, light-weight, non-capturing joints as shown in FIGS. 6, 7, 8 and ll.
The jointed arm 20 automatically returns and comes to rest at an intermediate linear or angular position, for example it returns to straight, as shown in FIG. l when the pressures in the four supply lines 39-1, 39-2, 39-3 and 39-4 are returned to their initial equal common-mode values of PO.
As shown in FIG. 5, when the pressure being supplied to the actuator string 70-1 is decreased below PO' the actuators ~LZ80785 80 in this ~tring 70-1 become elongated, causing the string 70-1 as a wh~le to elongate, while the pressure being 6upplied to the opposing actuator string 70-2 is increased above POI causing this latter ~tring as a whole to contract, thereby producing bending motion of the jointed arm 20. Thus, it will be under-stood that by varying the ~ettings of the components 94 and 95 in the two bridges 90-1 and 90-2, the jointed arm 20 can be caused to bend and move in any desired direction from the initial straight position shown in FIG~ 1. A sequence of such positions is shown in FIG. 21. The control motors 97, 98 in the two pneumatic bridges 90-1 and 90-2 are connected by electrical leads 101 to the control panel 100 which ~ontains a microproces-sor for automatically controlling movements of the jointed arm 20.
It is to be noted that unlike piston-type linear pneumatic actuators and unlike vane-type rotary pneumatic actuators, the opposed pneumatic tension actuators 80 provide the uni~ue and advantageous feature of coming to rest at a predeterminable intermediate specific position of the jointed an n 20 depending directly upon the opposed fluid pressures supplied to respective opposed strings 70 of actuators 80. Therefore, as the source 30 under control of the panel 100 is programmed to supply pressurized air at PO ~ ~P and PO - ~P, respectively, to the opposed actuator strings 70-1, 70-2 and 70-3 and 70-4, the various controlled positions of the arm 20 will vary in a predeterminable relationship with the various specific values of the pressure increments ~ P, as shown in FIG. 21. In other words, the various controlled positions of the arm 20 are pre-dictable because the curvature is a nearly linear function of variation of the controlled pressure increments, threby reducing complexity and cost.
Further, this feature of predictable and uniformly curved response of arm movements as a function of variations in the pressure ~ 785 alsoincrements ~ P/proYide~ an adv~ntageous nearly unif~rm 6tiffne~, i.e. a very nearly unif~rm bending stiffness, for all positions o r the arm 20.
In the elongated arm 20A ~hown in FIGS. 8 and 9 there are peg and groove socket joint~ 58, 54A, thus producing swinging movement of the jointed arm sections in a plane. As shown in FI~. lO, the links 50 have transver~e round rigid rod-like peg elements 58 attached to each end, forming a generally I-shaped or H-shaped configuration, depending upon the relative length of the transverse joint elements 58 in proportion to the length of the axial link 50.
The rigid plate elements 60A have a generally diamond or rhombus-shape configuration, and there are two opposed actuator strings 70-l and 70-2 fastened to apertures 62 located near the opposed tip portions of the plate elements 60A. It will be understood that-the controlled pressurized air supply 30 for this arm 20A includes only one pneumatic bridge 90-l (FIG. 3~ for operating the two opp~sed tension actuator strings 70-l and 70-2. The transverse pivot elements 58 are shown oriented perpendicular to a straight line passing through the centers of the apertures 62. The socket indentation~
54A are grooves extending for the full length of the transverse elements 58, and these grooves include barriers 59 at each end for preventing the peg elements 58 from inadvertently sliding along the grooves 54A in this pivotal mounting 58, 54A, 60A. By making the groove socket 54A with a larger radius of curvature than the xounded surface of the pivot element 58, a low-friction straight-line-contact 66 pivot action is provided.
In lieu of the peg and groove socket type of pivotal mounting 58, 54A, 50A, shown in FIGS. 8, 9 and lO, a knife-~2~ 85 edge S~A and groove 54A pivotal mounting can be used, as 6hown in FIGS. 11 and 12. The transverse rigid elements 58A have a triangular cro~s-sectional shape. The apex of this triangular pivot element 58A engages in the socket groove 54A for providing a very low-friction, straight-line 66 of pivot contact.
In the ~ointed arm 20B ~FIG. 13) there are opposed pairs of pneumatic tension actuators 80-1, 80-2 and 80-3, 80-4 which are offset away from opposite sides of the longitudinal axis 28 of the arm 20B. The inner end 21 of this arm 20B
is pivotally mounted upon a support 24, 26,for example such as a robot body, and the outer end 22 carries suitable termination means 40. The rigid links 50B-1 and 50R-2 each includes round rigid transverse peg elements 58 at their respective inner ends, which form pivotal joints by seating in non-capturing groove socket indentations 54A, ~imilar to those shown in FIGS. 8 and 9. These ~rooves 54A extend for the full length of the transverse pivot elements 58, and these grooves 54A include barriers at each end for preventing the pivot elements 58 from inadvertently sliding along the grooves 54A, similar to the barriers 59 (FIG. 9). Thus, it will be understood that the link elements 50B-1, 58 and 50B-2, 58 have generally a T-shaped con-figuration, with the stem ~OB extending axially along the arm axi 28 and constituting the shank of the T and with the transverse pivot element 58 extending perpendicular to the plane in which lies the arm axis 28 and consituting the cross bar of the T.
In order to attach the tension actuators 80, there are rigid attachment or anchoring elements 60~ projecting out on opposite sides of the arm axis 28 and oriented about the axis 28 at 90 relative to the length of the pivot elements 58. In other words, these attachment elements 60B lie in the same plane 1~80~85 as the arm axis 28. Near the elbow region 23, one ~f these attachments 60B' lies on the axis 28 of the inner link 50B-l.
The tension actuators 80 have their inner and outer end fittings 82, 83 attached by strong flexible tension cords 88 to the respective attachments 60B and 60B'. The passage or port in the outer end fitting 83 of each actuator i6 plugged air-tight at 87. The passage (port) in the inner end fittings 82 of the respective actuators 80-1, 80-2, 80-3 and 80-4 communi-cate with the four respective pressurized air supply lines 39-l, 39-2, 39-3 and 39-4 (FIGS. 3 and 4). Thus, the first pneumatic bridge 90-1 is employed to control the two opposed tension actuators 80-1 and 80-2 for controlling movements of the inner section of the arm 20B, this inner section being the portion between the shoulder region 21 and the elbow region 23. The ~econd pneumatic bridge 90-2 i~ employed to control the two opposed tension actuators 80-3 and 80-4 for c~ntrolling movements of the outer ~ection of this arm 20B, this outer ~ection being the portion betweèn the elbow region 23 and the wrist region 22.
The motions of the whole arm 20B are thereby advantageously con-trolled automatically in accordance with the programmin~ of the microprocessor in the control panel 100. Consequently, the advantageous common-mode pressure control method is achieved for this arm 20B with all of the resulting desirable features as explained before, namely: (1) the arm comes to rest, i.e.
it always assumes predeterminable (predictable) intermediate specific portions depending directly upon the differences in the opposed fluid pressures being supplied to the opposed pairs of actuators 80-1 and 80-2, 80-3 and 80-4; in other words, depending directly up~n the various ~pecific values (magnitudes) of the pressure increments ~ P; (2) the various controlled positions ~2 !30~8~;
of the arm will vary in a nearly linear relationship as a function of, i.e. in response to, the various specific values, i.e. the magnitudes, of the present increments ~ P; (3) a nearly uniform stiffness of the arm is achieved at all of its positions;
and (4~ a nearly uniform output impedance is achieved for all positions of the arm.
It is noted that the various pivotal mountings as described above advantageously involve simple, non-capturing, inexpensive, lightweight, low-friction types of pivot mounts having low-friction point contact or line contact pivot action.
This ability to utilize these non-capturing type of pivot mounts is provided because the opposed pneumatic actuators 80 operated in the method, as described, always produce a net compressive force on the pivots, as described above.
It is to be understood that capturing types of pivotal socket joints can be employed in the jointed arm 20, 20A and 20B, if desired. Such capturing types of pivotal mountings are, for example, ball and socket joints where the ball is captured in the socket, and hingepin joints, where the hirge pin is captured within encircling portions of the hinged elements, for example, as in cupboard door hinaes.
It will be understood from FIG. 5 that when the end fittings 82 and 83 are fastened into the apertures 62 of the plate elements 60 or 60A, then bending of the jointed arm 20 or 20A is accommodated by flexibing of the bladders 81 in the respective pneumatic tension actuators 80.
The ball-and-socket joints shown in FIGS. 5 and 15 could be either the capturing or non-capturing type.
One final comment about advantages in the use of pneumatic tension actuators 8~ they operate in accordance with lZ80785 the ~irst Law of thermodynamics ~energy conservation), namely, tension force "F" times differential change in length, i.e.
differential contraction, "dx" equals inflation pressure "P"
times differ~ntial volume "dv":
(1) F dx = P dv Solving for tension force gives:
FIELD pF THE INVENTION
The present invention is in the field of air-inElatable tension actuators which decrease in length as they are inflated and conversely which elongate as they are deflated, for example as shown in U.S. Patent No. 3,645,173 of John M. Yarlott, and as shown in my U.S. Patent No. 4,751,8~9 issued June 21, 1988. More particularly, this invention relates to a method and system employing elongated strings of such pneumatic tension actuators arranged and operated in opposed relationship in jointed arms, legs, beams and columns for controlling their movements, Eor example for controlling the movements of arms, legs, elephant trunks or flexible antennae in robots and for controlling the deflections of beams and columns in frames and structures.
BACKGROUND OF THE DISCLOSURE
Small-size robots performing precise but rapid light assembly tasks, have often utilized electric and/or hydraulic drive operators. The mass and weight of such conventional operators have tended to limit the dynamic response of prior robots and to dominate the total cost of such robots.
SUMMARY OF THE DISCLOSURE
The present invention provides a method and a system, wherein pneumatic tension actuators are interconnect~d in s~ries to form strings arranged for controLling elongated jointed arms and the like. Such strings of tension actuators extend along opposite sides of the elongated jointed arms and they act in opposition to each other for controlling its motions or deflections.
.c ~.. ~
~ iJ
The term "el~ngated jointed arm" i~ intended to be interpreted broadly to include various types o~ elongated jointec members, for example such as arms, legs, ele~hant trunks, flexible antennae, and the like, in robots and including beams and columns in chasses and carriages, all haviny a plurality of joints, with the joints being located at spaced p~sitions along the length of the jointed member.
The opposed tension actuators are inflated with con-trolled air pressures which are oppositely varied from a prede-termined common-mode pressure PO (initial fluid pressure level PO). In other words, as one string of tension actuators is beinc inflated with pressure increasing above PO, the opposed string is ~upplied with pressure decreasing below PO, for producing motion or deflection of the jointed arm in one direction, and conversely for producing motion or deflection in the other direc-tion~ The jointed arm includes elongated links arranyed in sequence in end-to-end relationship along the length or longi-tudinal axis of the arm. The first link in sequence is position-ed near a supporting structure or support body, for example such as the body of a robot, and has a pivotal mounting to this sup-port body, and the last link in the sequence is positioned and rigidly attached near the remote (or outer) end of the arm. Each successive link in the sequence has a single pivotal mounting to the preceding link for enabling the arm to bend and swing into various angular positions. Thus, the arm can curve or straighter , can swing up or down.
Fastened rigidly to the above-described rigid links, thexe are rigid elements for controlling the movements of the arm, with a respective one of these rigid elements being located at each pivotal mounting and projecting out on opposite sides of the longitudinal axis of the arm. The strings of pneumatic ~.ZE3~'78~
tension actuat~rs which h~ve been de~cribed ~8 extending along opposite sides of the jointed arm are off6et from, i.e. ~paced away from, the longitudinal axis of the arm. These ~trings are fastened to the respective rigid elements at fastening positions which are located at points located between tension actuators in the respective strings.
A controllable source of pressurized air communicates with the first tension actuator in each of the respective strings for controllably inflating the strings on opposite sides of the arm for producing arm motion, like muscles in the arm. By virtue of controlling the opposed strings of actuators with a common-mode pressure level PO, they are always exerting a net compress-ive force on each pivotal mounting, i.e. each joint, so advantageously permitting usage of simple, inexpensive, light-weight, non-capturing joints as shown. Moreover, the use of a common-mode pressure automatically causes the jointed arm to return to a prPdetermined mid-range rest position whenever air pressures are returned to PO. A nearly uniform stiffness (or mechanical output impedance) is provided at all arm positions by controlling the opposed pressures to be PO ~ ~ P and PO - ~P, where ~ P is a correspondin~ increment above and below the initial (common-mode) level PO.
The terms "air" and "pneumatic" and "gaseous fluid"
are intended to be interpreted broadly to include the various appropriate gaseous media capable of being economically employed to inflate tension actuators, for example air, mixtures of gases or individual gases, nitrogen, carbon dioxide, and the like.
In accordance with the present invention in one of its embodiments there is provided a gaseous-fluid-pressure actuated, elongated jointed arm having a longitudinal axis and ~L28~
capable Df being moved about in variou~ controlled directions, comprising: a plurality of rigid elements located at re~pective positions spaced along the axis of the arm, each o these elements extending across the axis and having first and cecond projections protruding outwardly on opposite sides of the axis, all of the first projections being on a first side of said axis and all of the 6econd projections being on the second ~ide of said axis. Each of these elements is oriented generally perpendicular to the neighboring portion of the longitudinal axis at the respective position where the element crosses the axis. mere are a plurality of elongated rigid links extending longitudinally along the axis, with respective ones of these links extending along the axis between successive elements, and with one end of each link having a pivoted relationship with the adjacent element. There are first and second pluralities of fluid-inflatable tension actuators, and each of these tension actuators has an inlet end and an outlet end. The tension actuators of the first plurality are joined end-to-end, forming a first inflatable string with the outlet end of each actuator communicating with the inlet end of the next actuator in the first string, and with the outlet end of the last actuator in the first string being blocked. The tension actuators of the second plurality are joined end-to-end forming a second inflatable string with the outlet end of each actuator communicating with the inlet end of the next actuator in the second string, and with the outlet end of the last actuator in the second string being blocked. The first string of tension actuators extends generally parallel with the axis of the arm and is offset f~om the axis on the first side of the axis, while the second string of tension actuators extends generally parallel with the axis and is offset from the axis on the second side thereof. The 1 ~28~17~
fir~t string cf tension actuatsr6 is anchored t~ the fir6t projection~ of said elements, with respective anchoring connections bein~ located at the ends of tension actuators in said first string, and the ~econd string of tension actuators is anchored to the ~econd projecti~ns of 6aid elements with each respective anchoring connection being located at the ends of tension actuators in the second string. Pressurized gaseous fluid control means communicate with the inlet ends of the first and second strings for controllably inflating these ~rings with pressurized fluid controllably varying in opposite directions from a common pressure level PO for causing the jointed arm to move and bend in various directions.
BRIEF DESCRIPTION OF THE DRAWINGS
The various features, objects, aspects and advantages of the present invention will become more fully understood from a consiaeration of the following-detailed description in conjunction with the accompanying drawings, which are not drawn to scale but are arranged for clarity of illustration.
In these drawings:
FIGURE 1 is a longitudinal sectional view of a jointed arm including a plurality of strings of air-inflated tension actuators acting in opposition to each other for producing controlled movements through controlled curvature and bending of the arm. FIG. 1 is a section taken along the line 1-1 in FIG. 2.
FIG. 2 is a cross-sectional view of the jointed arm of FIG. 1, being a section taken along the plane 2-2 in FIG. 1.
FIG. 3 is a schematic diagram of a controllable source oi pressurized gaseous fluid, for example air at various pressures for controlling contraction and elongation of the -G-~2~
strlng~ oi ten~ion a~tuator6. For ~larity ~ ~llu~trati~n, electrical re~istance 6ymbol6 and variable re~i~tance 6ymbol6 are shown in ~IG. 3 for explaining oper~tion o~ the control-lable air source.
~ IG. 4 is an enlargement of a portion of the dia-gram of FIG. 3 in which mechanical ~ymbol~ replace the electrical symbols for further explanation of the illustrative embodiments, and showing the control system.
~ IG. ~ illustrates movement of the various embodiments of the jointed arm shown in FIGS. 1-4 and in ~IGS. 6-12.
FIG. 6 is an enlargement of a portion of FIG. 1 included within the dashed and dotted circle for illustratin~
one embodiment of the pivotal joints in the arm.
FIG. 7 is a view similar to FIG. 6 and illustrating another embodiment of the pivotal joints in the arm.
FIG. 8 is a longitudinal sectional view of a portion of a jointe~
arm similar to FIG. 1, except that the pivotal joints have line contact, and therefore they act like hinges for allowing swinging movement of the arm back and forth along predetermined arcs of movement in a predetermined plane.
FIG. 9 is a cross-sectional view of the jointed arm of FIG. 8, being a section taken along the plane 9-9 in FIG. 8.
FIG. 10 is a perspective view of one of the links of the arm of FIGS. 8 and 9.
FIG. 11 illustrates a further embodiment of a pivotal joint for use in the arm of FIGS. 8 and 9.
FIG. 12 is a perspective view of the type of link used with the joints of FIG. 11.
FIG. 13 shows a further embodiment of an elongated jointed arm operated by opposed pairs of pneumatic tension actuators.
FIG. 1~ is an enlarged sectional view showiny the I couplings between successive tension actuators in a jointed arm.
~ IG. 15 is an enlarged ~ectional view showing in greater detail the ball-and-socket pivotal joint corre~ponding to the embodiment depicted in FIG. 5.
FIG. 16 illustrates a further embodiment of the compression-carrying link in the form of a compression element constructed as a pressurized chamber sealed by a fiber-rein-forced elastomeric oblate surface of revolution.
~ IG. 17 shows in cross section yet another embodiment of the compression element in the form of a pres-surized flexible annular shell, shaped like a laterally-compressed tire inner-tube.
FIG. 18 depicts an advantageous embodiment of my invention wherein the compressive load is carried by a pres-surized cell formed by an air-tight membrane envelope extend-ing between rigid circular end-plates and completely enclosing the tension actuators contained within.
FIG. 19 shows a cross-sectional view of the jointed-arm embodiment illustrated in FIG. 18, being a section taken along the plane A-A of FIG. 18.
FIG. 20 represents a longitudinal interior view of the same jointed-arm embodiment shown in FIGS. 18 and 19, being a cross section taken along the plane B-B of FIG. 19.
FIG. 21 indicates the variation in curvature and resulting movement of a multi-section embodiment as the control pressures are varied.
FIG. 22 shows a useful embodiment employing two jointed-arm sections terminating in a gripper, all of which have independent open-loop control.
FIG. 23 graphs the proportional variation in tension actuator spring-rate with actuator supply pressure.
FIG. 24 indicates quantitatively how the push-pull operation of the opposed actuator strings yields open-loop proportional con-trol of arm curvature as portrayed in FIGS. 5, 21 and 22.
~ ~8078~
DETAIL~D DESCRIPTI~N OP PRE~ERRED EMB~DIM~N~S
Inviting attention to ~IGS. 1 ~nd 2, there is ~hown an elongated jointed arm 20 having an inner end 21 and an outer or remote end 22. The inner end 21 of the arm i~ mounted upon a support 24, for example such as the body of a robot having a ~ase or frame 26. A controllable source 30 of pressurized gaseous fluid located near the support 24 serves to control the arm motions, as will be explained later. The outer end 22 of the arm 20 is shown carrying an article-handling mechanism 40 for grasping, handling or manipulating objects or articles, as will be explained later.
In lieu of this article-handling mechanism 40, the outer end of the elongated jointed member 20 may carry any suit-able termination, for example in the case vf a jointed leg, a termination such as a friction foot is used with a wear-resistant sole for engaging the floor or the ground; in the case of a jointed antenna or elephant trunk, the termination 40 includes a suitable sensor, which may be a mechanical proxi-mity or contact or shape sensor or shape tracer; the sensor may be an optical, thermal, magnetic, electrical or radiation sensor. The teimination 40 may be a suitable tool, for example such as a paintspray gun, weldiny tool or grasping or mani-pulating tool, and this termination may comprise one or more sensors plus one or more tools in cooperative association with each other. In cases where the jointed member 10 is employed as a column or beam in a frame or structure, then the termination 40 is a mechanical fastening or coupling for attach-ing the outer end 22 of this column or beam to another frame member or structural element.
!
~ 8-Finally, the termination 40 may in turn comprise an extended additional sequence of elongated jointed-arms, like 20 itself, joined in various ways, and constructed with similar or different dimensions and controlled by a variety of supplied pressures. A particular embodiment with two arms, 20F and 20G is portrayed in FIG. 22.
In summary, the elongated jointed member 20 may carry any suitable termination means 40 or combinations thereof on its outer end 22, as appropriate for the instal-lation and usage of this jointed member 20 in various o~s -8~-I
Extending along the longitudinal axi6 ~f the arm 20 is a sequence of elongated rigid links 50-1, 50-2, ~0-3, 5~-(n-1) and 50-n, where "n" is the number of jointed sections in the arm 20. Each of these links 50 is formed of ~trong, lightweight material, for example aluminum or fiber-reinforced plastic, and each link is shown having the shape of a round rod, preferably of tubular configuration for minimizing weight, mass and inertia while maximizing rigidity, with conically pointed or tapered ends. It is noted that the links 50 can have any desired cross-sectional configuration for optimizing strength and rigidity for resisting deflection under axial compression, for example such as an extruded H-shape or star shape, or square rectangular, triangular or hexagonal shape, and so forth; and in each case, these links 50 are configured for maximizing strength and rigidity while minimizing weight, mass and inertia.
As shown most clearly in FIG. 6, the pointed or taperl ~d ends 52 of each link 50 are received in a centrally located socket indentation 54 ]o~ate~ ,7n, the adiacent face of a rigid, generally square (See FIG.2) plate element 60. As shown in FIG. 1, there are a plurality of these plate elements 60-1, 60-2, 60-(n-1) and 60-n, with each of these plate elements 60 being positioned between the adjacent pointed end of the successive links 50 along the length of the arm 20. The last plate element 60-n is located at the outer or remote end 22 of the arm and : carries the termination means 40. Thus, each link 50 has a pivotal mounting 52, 54, 60 at one of its end~.
FIG. 7 illustrates an alternative embodiment of the pivotal mountings at the ends of the respective links 50.
These ends 52 are rounded and are received in axially aligned socket indentations 54 located in opposite faces of the rigid plate elements 60.
_g_ .2~3~7E~
It is noted that regardless oE the specific shape of the tapered link ends 54, as seen in FIGS. 6 and 7, they are tapered inwardly toward the longitudinal arm axis 28 for causing the tip of each tapered end 52 to have a small area of contac-t with the center of each socket 5~, which is aligned with the axis 28 for defining and forming a pivot point 56. Moreover, the sockets 54 each flare outwardly away from the axis 28 for providing clearance for enabling the links 50 to move or swlng into various angular positions relative to these plate elements 60, as illu.strated in FIGS. 5 & 15, where ball and socket joints are indicated.
Each of the plate elements 60 is formed oE strong, lightweight material similar to that used to make the links 50 for the same reasons, as before, namely for minimizing weight, mass and inertia while maximizing strength and rigidity. It is noted that in order to reduce the weight and mass of the generally square plate elements 60 they may have cut-outs (not shown). Such cut-outs are not shown in FIG. 2 for clarity of illustration, and because the use of weight-reducing cut-outs is known for inclusion in lightweight but strong, rigid mechanical elements. In the embodiments indicated in FIGS. 16-20, 22, the end plates 60 are taken to be circular.
In order to produce controlled motion of the arm 20, there are four strings 70-1, 70-2, 70-3, and 70-~ (FIG. 2) of pneumatic, inflatable tension actuators 80. These tension actuators 80 are constructed as described and shown in U.S.
Patent No. 3,6~5,173 of ~ohn M. Yarlott, or as shown in U.S.
Patent No. ~,751,869. Such tension actuators 80 have the advantageous operating characteristic that inflation causes them to lncrease in their enc]osed cross-sectional area and volume while simultaneously decreasing (contracting) in their axial length. In other words, as they bulge, they contract in their axial length. Conversely, when ~ 7 -~ ~28~7~3~
such ten~icn ~ctu~t~rs ~re ~efl~ted, ~.e. ~ they become m~re ~lim, they elongate. The disclo6ures ~f these two referenceç
are incorporated herein by reference, and the reader i~ invite~
to read them to appreciate more fully the de~irable qualities of lightweight, low mass, quick respon6e, xeliability, long life, simplicity and economy, which are provided by cuch ten6ion actuators 80.
It i6 noted that these tension actuators 80 are 8ym-metrical end-to-end~ and they each include an inflatable, elastomeric bladder (envelope or impermeable skin) 81 with a pai of end fittings 82 and 83 attached to this elastomeric bladder at each end. These sleeve-like end fitting~ 82 and 33 define axial passages or ports 84 and 85, respectively, communicating with theinterior region 86 of the bladder 81 for enabling the bladder to be inflated or deflated. The two end fittings 82 and 83 in each tension actuator 80 are identical, and their axial passages or ports 84 and 85 are identical. However, for clarity of explanation, it is useful to describe that end fittin~
82 a,nd its passage or port 84 of each actuator that is located nearer to the controlled, pressurized air supply 30 as being the input end and input passage (input port), while that other end fitting 83 and its passage or port 85 that is farther from the controlled air supply 30 is described as being the outlet end ant outlet passage (outlet port). It will be understood that durin inflation of the respective actuator strings 70-1, 70-2, 70-3 and 70-4, air flows from the source 30 thr~ugh four respective air conduits or airlines 39-1, 39-2, 39-3 and 39-4 into the inPut end 82 of the first tension actuator of the respective actuator strings 70, and through the actuator interior region 86 and thence through its outlet end fitting 83 into the input end fitting 82 of the next successive actuator in the respective string 70, and so forth.
I
lZ8~)71!3~
~ hu , the 6tring6 70-1, 70-2, 70 3 and 70-4 of tensivn actuator~ 80 are formed by coupling ~ucce~sive tension actuators together in end-to-end relationship with the passage or port 85 in the outlet end fitting B3 of each actuator in the string communicating with the inlet passage or port 84 in the inlet end fitting 82 of the next successive tension actuator in the string. The outlet passage 85 in the last tension actuator 80 in each string 70 is plugged air-tight at 87.
The inflatable bladders 81 each includes longitudinally extending, relatively inextensible filaments or strands of stron~ ~, flexible high tensile strength material, for example 6uch as Xevlar plastic, polyester, or polypropylene, as described in detail in the references above. These longitudinal filaments or strands are attached to the tubular end fittings 82, 83 for causing these end fittings to be pulled toward each other as the ~ladder 81 is inflated for producing axial contraction of the tension actuator.
In order to control motions of the arm 20, the four actuator strings, in clockwise (FIG. 2) order around the arm axis 28, referenced as 70-1, 70-3, 70-2 and 70-4, are offset from the arm axis 28, as seen most clearly in FIG. 2, and they are uniformly spaced apart 90 around the axis 28, ~eing located near the four corners of the square plate elements 60.
The first actuator string 70-1 on a first side of the arm axis 28 operates in opposition to the second actuator string 70-2 spaced 180 away, namely, on the other or second side of the axis. Similarly, the third actuator string 70-3 on one side of the axis 28 operates in opposition to the fourth actuator string 70-4 spaced 180 away on the opposite side of the axis. In summary, these four actuator strings are operated as two opposed pairE~.
11 Z80 7~35 These actuator 6trings 70-1, 7D-3, 70-2 and 70-4 are fastened ~anchored) to the respective corner~ of the plate elements 60 by connecting the end fittings 82, 83 to apertures 62 in these plate elements. For example, the respective end fittings 82,83 are air-tight cemented or bonded in end-to-end relationship in the respective apertures 62. An alternative assembly procedure is to use screw-threaded coupling sleeves as in FIG. 14 for coupling together the respective end fittings 82, 83. Such coupling sleeves are fitted through the apertures 62 in the plate elements 60, shown in FIG. 14.
The gripping mechanism 40 is shown as including a bracket 41 secured to the outer face of the outer plate element 60-n. A pair of opposed gripping fingers or jaws 4Z are hinged to the bracket 41 by pivot pins 43. For opening and closing these grippers 42, there is a double-acting cylinde~
and piston assembly 44 having its piston rod 45 pivotally pinnec at 46 to one gripper 42. The cylinder has a mounting rod 47 pivotally pinned at 48 to the other gripper 42. A pair of flexible air lines 49 communicates with the cylinder 44 at opposite ends. Feeding pressurized air through one of the lin~ ~s 49 into one end of the cylinder 44 causes the grippers 42 to 128078~i close toward each other, and conversely to open when pressuriz ed air is fed through the other line into the other end of the cylinder 44. These flexible air lines 44 are strung through holes 64 ~FIG. 2~ in the plate elements 60 located near the arm axis 28. Air source 30 (FIG. 3) includes line 51 supplying regulated pressurized air to pneumatic controller 53 connected to air lines 49 for operating the article handler 40. There are electrical leads 55 connected from the control-ler 53 to a control panel 100 (FIG. 4) including a microprocessor for automatic operation of the article handler 40.
In FIG. 3 is shown the controlled pressurized air supply 30 comprising an intake air filter 31, communicating with ambient air and connected into an air compressor 3~, whose output passes through a moisture eliminator 33, and through a further filter 34 capable of removing fine particles rom the compressed air. From the output of filter 34 an air supply line 35 leads to a pressure regulator 38 whose regulated output feeds into two branches 36, 37 which feed into two pneumatic bridge networks 90-1 and 90-2, which are analogous to electrical Wheatstone bridges.
i223078~
Each bridge network 90 includes a pair of pressure-dropping flow resistors 92 and 93 and a pair of remotely con-trollable pressure-dropping flow resistors 94 and 95 whose out-lets are vented to atmosphere at 96.
As ~hown in FIG. 4, the pressure-dropping flow resist-ors 92 and 93 are manually adjustable valves each providing a flow-impeding orifice, for example needle valves. The remotely controllable pressure-dropping flow resistors 94 and 95 are needle valves which are controllably adjusted by electric actuator 97 and 98, re ~ ctively, for example solenoids or else reversible stepping mDt~ ~rs.
The output supply line 39-1 is connected to the bridge 90-1 at the juncture of components 92 and 94, while the second output supply line 39-2 is connected to the opposite side of this pneumatic bridge at the juncture of components 93 and 95. Similarly, the third and fourth output supply lines 39-3 and 39-4 are connected to the respective corresponding junctures located on opposite sides of the other pneumatic bridge 90-2.
Consequently, the pressures of the air being fed through the four respective output supply lines 39-1 39 2, 39-3 and 39-4 are controlled by varying the settings of the needle valves 94 and 95 in the two pneumatic bridges 90-1 and 90-2~
The operation of these two pneumatic bridges 90-1 and 90-2 will now be explained. The pressure regulator 38 is set to supply a regulated air pressure of 2Po through the two branch lines 36 and 37 into the input junctione 99 of the two bridges ~L280~78~i 90-1 and 90-2. The four pressure-dropping flow resisting com-ponents 92, 93, 94 and 95 in each bridge are all initially 6et the ~ame. Con~equently, one-half of the pre~sure drop occurring from the input junction 99 to the vent 96 will take place in the components 92 and 93, and the other half of the pressure drop will take place in the components 94 and 95. The result is that the initial output pressure in all four of the output supply lines 39-1, 39-2, 39-3 and 39-4 will be the same, namely, one-half of the input pressure of 2Po. Thus, the initial pressure in lines 39-1, 39-Z, 39-3 and 39-4 is PO' which is called the initial supply pressure level.
This initial ~upply pressure level of PO may be at any desired gage pressure, where atmospheric pressure is taken as zero p.s.i. gage, in the range from 3 p.s.i.g. up to 120 p.s.i.g. depending upon the burst strength limit of the individu~ ll tension actuators 80.
When the pressure-dropping flow resistance of the component 94 in the bridge 90-1 i5 increased from its initial value, more than one-half of the total pressure drop occurring from the input junction 99 to the vent 96 now occurs across this component 94. Consequently, the pressure now appearing in the output line 39-1 is greater than PO. The larger the pressure drop occurring in the component 94, the nearer the pressure in the output line 39-1 approaches the 2Po regulated pressure level at the input junction 99.
Conversely, when the pressure-dropping flow resistan ce of the component 94 in the bridge 90-1 is decreased from its initial value, less than one-half of the total pressure drop now occurs across this component 94. Thus, the pressure now appearing in the output line 39-1 is less than PO. The smaller ~ 8~)'78S
the pressure drop occurring ~n the component 94, the nearer the pressure in the output line 39-1 approaches the ~ero gage pressure of the atmospheric vent 96.
The motors 97 and 98 are connected for adjusting the components 94 and 9S in a bridge 90 in opposite directions.
Consequently, the output pressures appearing in the two output lines 39-1 and 39-2 ~and also in the two output lines 39-3 and 39-4) vary in opposite directions from the initial pressure level PO. Preferably these controllable pressure-dropping components 94 and 95 are arranged to produce equal and opposite incrementc ~P above and below the initial pressure level P; so that the pressures in the two output lines 39-l and 39-2 (and also in the two output lines 39-3 and 39-4) have values of PO + ~ P.
A nearly uniform stiffnessor mechanical output impedance of the motions of the arm 20 is advantageously obtained by controlling the pressures in the bridge output lines 39-l and 39-2 (and also in the other bridge output lines 39-3 and 39-4) to vary by equal increments ~ P in opposite directions from the initial common-mode pressure level PO. Moreover, by controlling the opposed actuator strings with a common mode pressure level PO , these actuator strings are always exerting a net compressive force on each joint, so advantageously permitting usage of simple , inexpensive, light-weight, non-capturing joints as shown in FIGS. 6, 7, 8 and ll.
The jointed arm 20 automatically returns and comes to rest at an intermediate linear or angular position, for example it returns to straight, as shown in FIG. l when the pressures in the four supply lines 39-1, 39-2, 39-3 and 39-4 are returned to their initial equal common-mode values of PO.
As shown in FIG. 5, when the pressure being supplied to the actuator string 70-1 is decreased below PO' the actuators ~LZ80785 80 in this ~tring 70-1 become elongated, causing the string 70-1 as a wh~le to elongate, while the pressure being 6upplied to the opposing actuator string 70-2 is increased above POI causing this latter ~tring as a whole to contract, thereby producing bending motion of the jointed arm 20. Thus, it will be under-stood that by varying the ~ettings of the components 94 and 95 in the two bridges 90-1 and 90-2, the jointed arm 20 can be caused to bend and move in any desired direction from the initial straight position shown in FIG~ 1. A sequence of such positions is shown in FIG. 21. The control motors 97, 98 in the two pneumatic bridges 90-1 and 90-2 are connected by electrical leads 101 to the control panel 100 which ~ontains a microproces-sor for automatically controlling movements of the jointed arm 20.
It is to be noted that unlike piston-type linear pneumatic actuators and unlike vane-type rotary pneumatic actuators, the opposed pneumatic tension actuators 80 provide the uni~ue and advantageous feature of coming to rest at a predeterminable intermediate specific position of the jointed an n 20 depending directly upon the opposed fluid pressures supplied to respective opposed strings 70 of actuators 80. Therefore, as the source 30 under control of the panel 100 is programmed to supply pressurized air at PO ~ ~P and PO - ~P, respectively, to the opposed actuator strings 70-1, 70-2 and 70-3 and 70-4, the various controlled positions of the arm 20 will vary in a predeterminable relationship with the various specific values of the pressure increments ~ P, as shown in FIG. 21. In other words, the various controlled positions of the arm 20 are pre-dictable because the curvature is a nearly linear function of variation of the controlled pressure increments, threby reducing complexity and cost.
Further, this feature of predictable and uniformly curved response of arm movements as a function of variations in the pressure ~ 785 alsoincrements ~ P/proYide~ an adv~ntageous nearly unif~rm 6tiffne~, i.e. a very nearly unif~rm bending stiffness, for all positions o r the arm 20.
In the elongated arm 20A ~hown in FIGS. 8 and 9 there are peg and groove socket joint~ 58, 54A, thus producing swinging movement of the jointed arm sections in a plane. As shown in FI~. lO, the links 50 have transver~e round rigid rod-like peg elements 58 attached to each end, forming a generally I-shaped or H-shaped configuration, depending upon the relative length of the transverse joint elements 58 in proportion to the length of the axial link 50.
The rigid plate elements 60A have a generally diamond or rhombus-shape configuration, and there are two opposed actuator strings 70-l and 70-2 fastened to apertures 62 located near the opposed tip portions of the plate elements 60A. It will be understood that-the controlled pressurized air supply 30 for this arm 20A includes only one pneumatic bridge 90-l (FIG. 3~ for operating the two opp~sed tension actuator strings 70-l and 70-2. The transverse pivot elements 58 are shown oriented perpendicular to a straight line passing through the centers of the apertures 62. The socket indentation~
54A are grooves extending for the full length of the transverse elements 58, and these grooves include barriers 59 at each end for preventing the peg elements 58 from inadvertently sliding along the grooves 54A in this pivotal mounting 58, 54A, 60A. By making the groove socket 54A with a larger radius of curvature than the xounded surface of the pivot element 58, a low-friction straight-line-contact 66 pivot action is provided.
In lieu of the peg and groove socket type of pivotal mounting 58, 54A, 50A, shown in FIGS. 8, 9 and lO, a knife-~2~ 85 edge S~A and groove 54A pivotal mounting can be used, as 6hown in FIGS. 11 and 12. The transverse rigid elements 58A have a triangular cro~s-sectional shape. The apex of this triangular pivot element 58A engages in the socket groove 54A for providing a very low-friction, straight-line 66 of pivot contact.
In the ~ointed arm 20B ~FIG. 13) there are opposed pairs of pneumatic tension actuators 80-1, 80-2 and 80-3, 80-4 which are offset away from opposite sides of the longitudinal axis 28 of the arm 20B. The inner end 21 of this arm 20B
is pivotally mounted upon a support 24, 26,for example such as a robot body, and the outer end 22 carries suitable termination means 40. The rigid links 50B-1 and 50R-2 each includes round rigid transverse peg elements 58 at their respective inner ends, which form pivotal joints by seating in non-capturing groove socket indentations 54A, ~imilar to those shown in FIGS. 8 and 9. These ~rooves 54A extend for the full length of the transverse pivot elements 58, and these grooves 54A include barriers at each end for preventing the pivot elements 58 from inadvertently sliding along the grooves 54A, similar to the barriers 59 (FIG. 9). Thus, it will be understood that the link elements 50B-1, 58 and 50B-2, 58 have generally a T-shaped con-figuration, with the stem ~OB extending axially along the arm axi 28 and constituting the shank of the T and with the transverse pivot element 58 extending perpendicular to the plane in which lies the arm axis 28 and consituting the cross bar of the T.
In order to attach the tension actuators 80, there are rigid attachment or anchoring elements 60~ projecting out on opposite sides of the arm axis 28 and oriented about the axis 28 at 90 relative to the length of the pivot elements 58. In other words, these attachment elements 60B lie in the same plane 1~80~85 as the arm axis 28. Near the elbow region 23, one ~f these attachments 60B' lies on the axis 28 of the inner link 50B-l.
The tension actuators 80 have their inner and outer end fittings 82, 83 attached by strong flexible tension cords 88 to the respective attachments 60B and 60B'. The passage or port in the outer end fitting 83 of each actuator i6 plugged air-tight at 87. The passage (port) in the inner end fittings 82 of the respective actuators 80-1, 80-2, 80-3 and 80-4 communi-cate with the four respective pressurized air supply lines 39-l, 39-2, 39-3 and 39-4 (FIGS. 3 and 4). Thus, the first pneumatic bridge 90-1 is employed to control the two opposed tension actuators 80-1 and 80-2 for controlling movements of the inner section of the arm 20B, this inner section being the portion between the shoulder region 21 and the elbow region 23. The ~econd pneumatic bridge 90-2 i~ employed to control the two opposed tension actuators 80-3 and 80-4 for c~ntrolling movements of the outer ~ection of this arm 20B, this outer ~ection being the portion betweèn the elbow region 23 and the wrist region 22.
The motions of the whole arm 20B are thereby advantageously con-trolled automatically in accordance with the programmin~ of the microprocessor in the control panel 100. Consequently, the advantageous common-mode pressure control method is achieved for this arm 20B with all of the resulting desirable features as explained before, namely: (1) the arm comes to rest, i.e.
it always assumes predeterminable (predictable) intermediate specific portions depending directly upon the differences in the opposed fluid pressures being supplied to the opposed pairs of actuators 80-1 and 80-2, 80-3 and 80-4; in other words, depending directly up~n the various ~pecific values (magnitudes) of the pressure increments ~ P; (2) the various controlled positions ~2 !30~8~;
of the arm will vary in a nearly linear relationship as a function of, i.e. in response to, the various specific values, i.e. the magnitudes, of the present increments ~ P; (3) a nearly uniform stiffness of the arm is achieved at all of its positions;
and (4~ a nearly uniform output impedance is achieved for all positions of the arm.
It is noted that the various pivotal mountings as described above advantageously involve simple, non-capturing, inexpensive, lightweight, low-friction types of pivot mounts having low-friction point contact or line contact pivot action.
This ability to utilize these non-capturing type of pivot mounts is provided because the opposed pneumatic actuators 80 operated in the method, as described, always produce a net compressive force on the pivots, as described above.
It is to be understood that capturing types of pivotal socket joints can be employed in the jointed arm 20, 20A and 20B, if desired. Such capturing types of pivotal mountings are, for example, ball and socket joints where the ball is captured in the socket, and hingepin joints, where the hirge pin is captured within encircling portions of the hinged elements, for example, as in cupboard door hinaes.
It will be understood from FIG. 5 that when the end fittings 82 and 83 are fastened into the apertures 62 of the plate elements 60 or 60A, then bending of the jointed arm 20 or 20A is accommodated by flexibing of the bladders 81 in the respective pneumatic tension actuators 80.
The ball-and-socket joints shown in FIGS. 5 and 15 could be either the capturing or non-capturing type.
One final comment about advantages in the use of pneumatic tension actuators 8~ they operate in accordance with lZ80785 the ~irst Law of thermodynamics ~energy conservation), namely, tension force "F" times differential change in length, i.e.
differential contraction, "dx" equals inflation pressure "P"
times differ~ntial volume "dv":
(1) F dx = P dv Solving for tension force gives:
(2) F = PdX
Therefore, the tension force F is directly proportional to the inflation pressure P within the interior region 86 of each bladder 81 multiplied by the incremental rate of change of volume dv with respect to incremental rate of change in length dx of the actuator. When the bladder Bl and its longitudinal strands or filaments are architectured for maintaining dv substantially constant throughout the range of contraction, then the tension force F is directly proportional to the inflation pressure P as shown in FIG. 23. In other words, the tension actuators act like linear tension springs in accordance with Hooke's Law; when fully extended the tension force is maximum, and when fully contracted the tension force is minimum. The values of X are shown in FIG. 23 as negative, because a con-traction is produced.
When according to my invention, as disclosed above and claimed below, the tension actuators and actuator strings are used in opposition, the relation between control pressure (+ ~P) and resulting curvature (+ K) follows necessarily from the geometric constraints:
Therefore, the tension force F is directly proportional to the inflation pressure P within the interior region 86 of each bladder 81 multiplied by the incremental rate of change of volume dv with respect to incremental rate of change in length dx of the actuator. When the bladder Bl and its longitudinal strands or filaments are architectured for maintaining dv substantially constant throughout the range of contraction, then the tension force F is directly proportional to the inflation pressure P as shown in FIG. 23. In other words, the tension actuators act like linear tension springs in accordance with Hooke's Law; when fully extended the tension force is maximum, and when fully contracted the tension force is minimum. The values of X are shown in FIG. 23 as negative, because a con-traction is produced.
When according to my invention, as disclosed above and claimed below, the tension actuators and actuator strings are used in opposition, the relation between control pressure (+ ~P) and resulting curvature (+ K) follows necessarily from the geometric constraints:
(3) Curvature K = l/R -- A/L = L~X/D, where R,A,L, and D are as indicated in FIG. 5 and ~ X is as shown in FIG. 23.
1'~8~
Also ~IGS. 16 through 20 show useEul embodiments where the compression-carrying links 50 are embodied in suitable oblate or toroidal compressive air-springs (or air-actuators).
Jointed -arms in this form have particular value if the arms must be compactly stowed when not in use.
Correspondin~ reference numbers are used throughout the various FIGURES for indicating the same elements and for indicating elements which perform corresponding functions even though their physical structures or shapes may be somewhat different.
While the novel features of the invention have been illustrated and described in connection with specific embodiments of the invention, it is beieved that these embodi-ments will enable others skilled inthe art to apply the principles of the invention in forms departing from the exemplary embodiments herein, and such departures are contempled by the ~e~e2 L~ y~ e~e~ ~- eb~ e~e~e~
1'~8~
Also ~IGS. 16 through 20 show useEul embodiments where the compression-carrying links 50 are embodied in suitable oblate or toroidal compressive air-springs (or air-actuators).
Jointed -arms in this form have particular value if the arms must be compactly stowed when not in use.
Correspondin~ reference numbers are used throughout the various FIGURES for indicating the same elements and for indicating elements which perform corresponding functions even though their physical structures or shapes may be somewhat different.
While the novel features of the invention have been illustrated and described in connection with specific embodiments of the invention, it is beieved that these embodi-ments will enable others skilled inthe art to apply the principles of the invention in forms departing from the exemplary embodiments herein, and such departures are contempled by the ~e~e2 L~ y~ e~e~ ~- eb~ e~e~e~
Claims (40)
1. A fluid-pressure actuated elongated jointed member having a longitudinal axis and capable of being moved about in various controlled directions, comprising:
a plurality of rigid elements located at respective positions spaced along said axis, each of said elements extending across the axis and having first and second projections projecting outwardly on opposite sides of the axis, all of said first projections being on a first side of said axis and all of said second projections being on the second side of said axis, said second side being opposite to said first side, each of said elements being oriented generally perpendicular to the neighbouring portion of the longitudinal axis at the respective position where the element crosses the axis, a plurality of compression-carrying links positioned concentrically along the axis, respective ones of said links extending between successive elements, each link being rigidly connected to an element and having a pivotal relationship with the adjacent element, first and second pluralities of fluid-inflatable tension actuators, each of said tension actuators having an inlet end and an outlet end, the tension actuators of the first plurality being joined end-to-end for forming a first inflatable string with the outlet end of each actuator in said first string communicating with the inlet end of the next actuator in said first string, and with the outlet end of the last actuator in said first string being blocked, means for feeding pressurized fluid into the inlet end of said first string of tension actuators, the tension actuators of the second plurality being joined end-to-end for forming a second inflatable string with the outlet end of each actuator in said second string communicating with the inlet end of the next actuator in said second string, and with the outlet end of the last actuator in said second string being blocked, means for feeding pressurized fluid into the inlet end of said second string of tension actuators, the first string of tension actuators extending generally parallel with said axis and being offset from said axis on the first side of said axis, the second string of tension actuators extending generally parallel with said axis and being offset from said axis on the second side of said axis, said first string of tension actuators being fastened to the first projections of said elements with respective fastening connections being located near ends of tension actuators in said first string, and said second string of tension actuators being fastened to the second projections of said elements with respective fastening connections being located near ends of tension actuators in said second string.
a plurality of rigid elements located at respective positions spaced along said axis, each of said elements extending across the axis and having first and second projections projecting outwardly on opposite sides of the axis, all of said first projections being on a first side of said axis and all of said second projections being on the second side of said axis, said second side being opposite to said first side, each of said elements being oriented generally perpendicular to the neighbouring portion of the longitudinal axis at the respective position where the element crosses the axis, a plurality of compression-carrying links positioned concentrically along the axis, respective ones of said links extending between successive elements, each link being rigidly connected to an element and having a pivotal relationship with the adjacent element, first and second pluralities of fluid-inflatable tension actuators, each of said tension actuators having an inlet end and an outlet end, the tension actuators of the first plurality being joined end-to-end for forming a first inflatable string with the outlet end of each actuator in said first string communicating with the inlet end of the next actuator in said first string, and with the outlet end of the last actuator in said first string being blocked, means for feeding pressurized fluid into the inlet end of said first string of tension actuators, the tension actuators of the second plurality being joined end-to-end for forming a second inflatable string with the outlet end of each actuator in said second string communicating with the inlet end of the next actuator in said second string, and with the outlet end of the last actuator in said second string being blocked, means for feeding pressurized fluid into the inlet end of said second string of tension actuators, the first string of tension actuators extending generally parallel with said axis and being offset from said axis on the first side of said axis, the second string of tension actuators extending generally parallel with said axis and being offset from said axis on the second side of said axis, said first string of tension actuators being fastened to the first projections of said elements with respective fastening connections being located near ends of tension actuators in said first string, and said second string of tension actuators being fastened to the second projections of said elements with respective fastening connections being located near ends of tension actuators in said second string.
2. A fluid-pressure actuated jointed member as claimed in claim 1, and in which:
pressurized fluid control means communicates with the inlet ends of the first and second strings of tension actuators for inflating said first and second strings with pressurized fluid controllably varying by equal pressure increments .DELTA.P in opposite directions from a common pressure level Po for causing the jointed member to move into various positions coming to rest at various predetermined predictable positions depending directly upon the various specific values of the pressure increments.DELTA.P.
pressurized fluid control means communicates with the inlet ends of the first and second strings of tension actuators for inflating said first and second strings with pressurized fluid controllably varying by equal pressure increments .DELTA.P in opposite directions from a common pressure level Po for causing the jointed member to move into various positions coming to rest at various predetermined predictable positions depending directly upon the various specific values of the pressure increments.DELTA.P.
3. A fluid-pressure actuated jointed member as claimed in claim 2, in which:
said pressurized fluid control means comprises:
a source of pressurized air at regulated pressure, four pressure-dropping flow resisting components connected to form a four-sided pneumatic bridge network having four corners, with an inlet junction and a vent to atmosphere located at two opposite corners of said bridge and wherein there are two junctions located at the respective other two opposite corners of the bridge forming first and second outlets from the bridge, said source of pressurized air is connected to said inlet junction for supplying pressurized air at regulated pressure to the bridge, the first pressure-dropping flow resisting component located between said inlet junction and said first outlet is equal in effect to the second pressure-dropping flow resisting component located between said inlet junction and said second outlet, the third pressure-dropping flow resisting component is located between said first outlet and said vent, the fourth pressure-dropping flow resisting component is located between said second outlet and said vent, said first and second outlets respectively communicate with said inlet ends of said first and second actuator strings, and variable control means are connected to said third and fourth components for varying their pressure-dropping effects by equal amounts in opposite directions from an initially equal condition.
said pressurized fluid control means comprises:
a source of pressurized air at regulated pressure, four pressure-dropping flow resisting components connected to form a four-sided pneumatic bridge network having four corners, with an inlet junction and a vent to atmosphere located at two opposite corners of said bridge and wherein there are two junctions located at the respective other two opposite corners of the bridge forming first and second outlets from the bridge, said source of pressurized air is connected to said inlet junction for supplying pressurized air at regulated pressure to the bridge, the first pressure-dropping flow resisting component located between said inlet junction and said first outlet is equal in effect to the second pressure-dropping flow resisting component located between said inlet junction and said second outlet, the third pressure-dropping flow resisting component is located between said first outlet and said vent, the fourth pressure-dropping flow resisting component is located between said second outlet and said vent, said first and second outlets respectively communicate with said inlet ends of said first and second actuator strings, and variable control means are connected to said third and fourth components for varying their pressure-dropping effects by equal amounts in opposite directions from an initially equal condition.
4. A fluid-pressure actuated jointed member as claimed in claim 2, in which:
ends of the links have low-friction non-captured pivotal relationships with the adjacent elements, and said first and second strings of tension actuators exert a net compressive force on said pivotal relationships in all positions of the jointed member, thereby preventing separation of the links from the elements in spite of being non-captured.
ends of the links have low-friction non-captured pivotal relationships with the adjacent elements, and said first and second strings of tension actuators exert a net compressive force on said pivotal relationships in all positions of the jointed member, thereby preventing separation of the links from the elements in spite of being non-captured.
5. A fluid-pressure actuated jointed member as claimed in claim 1, in which:
said elements have pairs of straight grooves facing in opposite directions, said pair of straight grooves in each element are parallel with each other and each groove intersects the longitudinal axis of the jointed member, said pair of parallel straight grooves in each element are oriented perpendicular to a straight line passing through the respective fastening connections on said first and second fastening connections on said first and second projections of the element, and the pivotal relationship of the links with said elements comprises a transverse straight pivot rod on an end of each link rotatably seating in one of said grooves.
said elements have pairs of straight grooves facing in opposite directions, said pair of straight grooves in each element are parallel with each other and each groove intersects the longitudinal axis of the jointed member, said pair of parallel straight grooves in each element are oriented perpendicular to a straight line passing through the respective fastening connections on said first and second fastening connections on said first and second projections of the element, and the pivotal relationship of the links with said elements comprises a transverse straight pivot rod on an end of each link rotatably seating in one of said grooves.
6. A fluid-pressure actuated jointed member as claimed in claim 1, in which:
said elements have first, second, third and fourth projections projecting outwardly from the axis and oriented with respect to each other about 90° around the longitudinal axis of the arm, there are first, second, third and fourth pluralities of fluid-inflatable tension actuators respectively joined end-to-end forming first, second, third and fourth strings of tension actuators, said four strings of tension actuators all extend generally parallel with the axis and all are offset from the axis and are located at spaced positions separated from each other about 90° around said longitudinal axis, and said first, second, third and fourth strings of tension actuators being fastened to the respective first, second, third and fourth projections of said elements for being the jointed member in various directions by varying the internal pressures of the tension actuators in the various strings.
said elements have first, second, third and fourth projections projecting outwardly from the axis and oriented with respect to each other about 90° around the longitudinal axis of the arm, there are first, second, third and fourth pluralities of fluid-inflatable tension actuators respectively joined end-to-end forming first, second, third and fourth strings of tension actuators, said four strings of tension actuators all extend generally parallel with the axis and all are offset from the axis and are located at spaced positions separated from each other about 90° around said longitudinal axis, and said first, second, third and fourth strings of tension actuators being fastened to the respective first, second, third and fourth projections of said elements for being the jointed member in various directions by varying the internal pressures of the tension actuators in the various strings.
7. A fluid-pressure actuated jointed member as claimed in claim 6, and in which:
first pressurized fluid control means communicates with the inlet ends of the first and second actuator strings, second pressurized fluid control means communicates with the inlet ends of the third and fourth actuator strings, said first pressurized fluid control means inflates said first and second actuator strings with pressurized fluid controllably varying by equal pressure increments.DELTA.P in opposite directions from a common pressure level Po, and said second pressurized fluid control means inflates said third and fourth actuator strings with pressure increments .DELTA.P in opposite directions from the same common pressure level Po, bending said jointed member in various directions with the jointed member assuming various predictable predetermined positions determined by the various values of the equal and opposite pressure increments.DELTA.P.
first pressurized fluid control means communicates with the inlet ends of the first and second actuator strings, second pressurized fluid control means communicates with the inlet ends of the third and fourth actuator strings, said first pressurized fluid control means inflates said first and second actuator strings with pressurized fluid controllably varying by equal pressure increments.DELTA.P in opposite directions from a common pressure level Po, and said second pressurized fluid control means inflates said third and fourth actuator strings with pressure increments .DELTA.P in opposite directions from the same common pressure level Po, bending said jointed member in various directions with the jointed member assuming various predictable predetermined positions determined by the various values of the equal and opposite pressure increments.DELTA.P.
8. A fluid-pressure actuated elongated jointed member as claimed in claim 7, in which:
said first pressurized fluid control means and said second pressurized fluid control means each comprises:
a source of pressurized air at regulated pressure, four pressure-dropping flow resisting components connected to form a four-sided pneumatic bridge network having four corners, with an inlet junction and a vent to atmosphere located at two opposite corners of said bridge and wherein there are two junctions located at the respective other two opposite corners of the bridge forming first and second outlets from the bridge network, said source of pressurized air is connected to said inlet junction for supplying pressurized air at regulated pressure to the bridge network, the first pressure-dropping low resisting component located between said inlet junction and said first outlet is equal in effect to the second pressure-dropping flow resisting component located between said inlet junction and said second outlet, the third pressure-dropping flow resisting component is located between said first outlet and said vent, the fourth pressure-dropping flow resisting component is located between said second outlet and said vent, and said first and second outlets of one of said bridge networks respectively communicate with the inlet ends of said first and second actuator strings, and the first and second outlets of the other of said bridge networks respectively communicate with the inlet ends of said third and fourth actuator strings, and variable control means connected to said third and fourth components in each bridge network for varying their pressure-dropping effects by equal amounts in opposite directions from an initially equal condition.
said first pressurized fluid control means and said second pressurized fluid control means each comprises:
a source of pressurized air at regulated pressure, four pressure-dropping flow resisting components connected to form a four-sided pneumatic bridge network having four corners, with an inlet junction and a vent to atmosphere located at two opposite corners of said bridge and wherein there are two junctions located at the respective other two opposite corners of the bridge forming first and second outlets from the bridge network, said source of pressurized air is connected to said inlet junction for supplying pressurized air at regulated pressure to the bridge network, the first pressure-dropping low resisting component located between said inlet junction and said first outlet is equal in effect to the second pressure-dropping flow resisting component located between said inlet junction and said second outlet, the third pressure-dropping flow resisting component is located between said first outlet and said vent, the fourth pressure-dropping flow resisting component is located between said second outlet and said vent, and said first and second outlets of one of said bridge networks respectively communicate with the inlet ends of said first and second actuator strings, and the first and second outlets of the other of said bridge networks respectively communicate with the inlet ends of said third and fourth actuator strings, and variable control means connected to said third and fourth components in each bridge network for varying their pressure-dropping effects by equal amounts in opposite directions from an initially equal condition.
9. A fluid-pressure actuated jointed member as claimed in claim 6, in which:
said elements have a socket aligned with the longitudinal axis, and the pivotal relationship of the ends of the links with said elements comprises ends of the links received in said sockets.
said elements have a socket aligned with the longitudinal axis, and the pivotal relationship of the ends of the links with said elements comprises ends of the links received in said sockets.
10. A fluid-pressure actuated jointed member as claimed in claim 9, in which:
said ends of said links are tapered and are received in said sockets in low-friction non-captured relationships, and said four actuator strings exert a net compressive force on said tapered ends and sockets in all positions of the jointed member, thereby retaining said tapered ends in said sockets in spite of their non-captured relationship with their sockets.
said ends of said links are tapered and are received in said sockets in low-friction non-captured relationships, and said four actuator strings exert a net compressive force on said tapered ends and sockets in all positions of the jointed member, thereby retaining said tapered ends in said sockets in spite of their non-captured relationship with their sockets.
11. The method for controlling movements of an elongated arm having a longitudinal axis comprising the steps of:
providing a pivotal mounting between one end of said arm and a support, positioning first and second effectively identical fluid-inflatable tension actuators on opposite sides of said arm with said actuators extending generally parallel with the axis and being offset away from the axis on opposite sides of the arm, connecting each tension actuator between the support and corresponding positions on the arm on opposite sides of the arm for causing the tension forces of said actuators acting on the arm to be opposed to each other, inflating the first and second opposed tension actuators with pressurized gaseous fluid controllably varying by equal pressure increments.DELTA.P in opposite directions from a common pressure level PO for causing the arm to assume various predictable predetermined positions depending directly upon the various values of the pressure increments.DELTA.P, said various predictable predetermined positions of the arm varying in a nearly linear relationship in response to the various specific values of the pressure increments .DELTA.P, and said arm having a nearly uniform stiffness at all of its positions.
providing a pivotal mounting between one end of said arm and a support, positioning first and second effectively identical fluid-inflatable tension actuators on opposite sides of said arm with said actuators extending generally parallel with the axis and being offset away from the axis on opposite sides of the arm, connecting each tension actuator between the support and corresponding positions on the arm on opposite sides of the arm for causing the tension forces of said actuators acting on the arm to be opposed to each other, inflating the first and second opposed tension actuators with pressurized gaseous fluid controllably varying by equal pressure increments.DELTA.P in opposite directions from a common pressure level PO for causing the arm to assume various predictable predetermined positions depending directly upon the various values of the pressure increments.DELTA.P, said various predictable predetermined positions of the arm varying in a nearly linear relationship in response to the various specific values of the pressure increments .DELTA.P, and said arm having a nearly uniform stiffness at all of its positions.
12. The method for controlling movements of an elongated arm as claimed in claim 11, including the further steps of:
providing pressurized air at a regulated pressure of 2Po, feeding some of such regulated pressurized air through first and second pressure-dropping components in serial relation and venting to atmosphere after flowing through the second component, placing the first tension actuator in communication with a first outlet point in the flow path through said first and second components, such first outlet point being located between said first and second components, feeding some of such regulated pressurized air through third and fourth pressure-dropping components in serial relationship and venting to atmosphere after flowing through the fourth component, placing the second tension actuator in communication with a second outlet point in the flow path through said third and fourth components, such second outlet point being located between said third and fourth components, initially setting the pressure-dropping effects of said first, second, third and fourth components to be equal for providing pressurized air at the same common pressure level Po from said first and second outlets, and controllably varying the pressure-dropping effects of said third and fourth components in opposite directions from their initial effects for causing the pressurized air supplied from said first and second outlets to said first and second tension actuators to vary in opposite directions by equal pressure increments.DELTA.P.
providing pressurized air at a regulated pressure of 2Po, feeding some of such regulated pressurized air through first and second pressure-dropping components in serial relation and venting to atmosphere after flowing through the second component, placing the first tension actuator in communication with a first outlet point in the flow path through said first and second components, such first outlet point being located between said first and second components, feeding some of such regulated pressurized air through third and fourth pressure-dropping components in serial relationship and venting to atmosphere after flowing through the fourth component, placing the second tension actuator in communication with a second outlet point in the flow path through said third and fourth components, such second outlet point being located between said third and fourth components, initially setting the pressure-dropping effects of said first, second, third and fourth components to be equal for providing pressurized air at the same common pressure level Po from said first and second outlets, and controllably varying the pressure-dropping effects of said third and fourth components in opposite directions from their initial effects for causing the pressurized air supplied from said first and second outlets to said first and second tension actuators to vary in opposite directions by equal pressure increments.DELTA.P.
13. A fluid-pressure actuatable elongated jointed arm having an axis extending along the length of the arm, said arm being capable of reaching in various controlled directions, comprising:
base means, a plurality of elongated links arranged in sequence in end-to-end relationship along the length of the axis of said arm, the first of said links in said sequence being positioned near said base means and the last of said links in said sequence being positioned remote from said base means, the first of said links having a pivotal mounting to said base means for enabling said first link to swing into various angular positions relative to said base means, each successive link in said sequence having a pivotal mounting to the preceding link in said sequence for enabling each successive link to swing into various angular positions relative to the preceding link, a plurality of rigid elements, respective ones of said rigid elements being connected to the respective pivotal mountings between links, said rigid elements projecting out on opposite sides of said axis, a first plurality of fluid-inflatable tension actuators connected in sequence in end-to-end relationship with each actuator in the sequence communicating with the next successive actuator forming a first inflatable string of tension actuators, a second plurality of fluid-inflatable tension actuators connected in sequence in end-to-end relationship with each actuator in the sequence communicating with the next successive actuator forming a second inflatable string of tension actuators, the first string of tension actuators extending along the length of the arm and being offset to a first side of the axis, said second string of tension actuators extending along the length of the arm and being offset to a second side of the axis opposite to said first side, said first string of tension actuators being attached to the respective rigid elements at attachment positions offset to the first side of the axis, said attachment positions being located along the first string at points located between tension actuators in the first string, said second string of tension actuators being attached to the respective rigid elements at attachment positions offset to the second side of the axis, and said latter attachment positions being located along the second string at points located between tension actuators in the second string.
base means, a plurality of elongated links arranged in sequence in end-to-end relationship along the length of the axis of said arm, the first of said links in said sequence being positioned near said base means and the last of said links in said sequence being positioned remote from said base means, the first of said links having a pivotal mounting to said base means for enabling said first link to swing into various angular positions relative to said base means, each successive link in said sequence having a pivotal mounting to the preceding link in said sequence for enabling each successive link to swing into various angular positions relative to the preceding link, a plurality of rigid elements, respective ones of said rigid elements being connected to the respective pivotal mountings between links, said rigid elements projecting out on opposite sides of said axis, a first plurality of fluid-inflatable tension actuators connected in sequence in end-to-end relationship with each actuator in the sequence communicating with the next successive actuator forming a first inflatable string of tension actuators, a second plurality of fluid-inflatable tension actuators connected in sequence in end-to-end relationship with each actuator in the sequence communicating with the next successive actuator forming a second inflatable string of tension actuators, the first string of tension actuators extending along the length of the arm and being offset to a first side of the axis, said second string of tension actuators extending along the length of the arm and being offset to a second side of the axis opposite to said first side, said first string of tension actuators being attached to the respective rigid elements at attachment positions offset to the first side of the axis, said attachment positions being located along the first string at points located between tension actuators in the first string, said second string of tension actuators being attached to the respective rigid elements at attachment positions offset to the second side of the axis, and said latter attachment positions being located along the second string at points located between tension actuators in the second string.
14. A fluid-pressure actuatable elongated jointed arm as claimed in claim 13, in which:
controllable pressurized fluid supply means communicates with said first and second strings of tension actuators for controlling inflating said first and second strings of tension actuators with respective first and second sources of pressurized fluid variable oppositely upwardly and downwardly from a common pressure level Po for causing the arm to reach in various directions from said base means.
controllable pressurized fluid supply means communicates with said first and second strings of tension actuators for controlling inflating said first and second strings of tension actuators with respective first and second sources of pressurized fluid variable oppositely upwardly and downwardly from a common pressure level Po for causing the arm to reach in various directions from said base means.
15. A fluid-pressure actuatable elongated jointed arm as claimed in claim 14, in which:
said first and second sources of pressurized fluid are oppositely varied by equal pressure increments .DELTA.P upwardly and downwardly, respectively, from a common pressure level Po for causing the arm to reach into various predeterminable predictable specific positions depending directly upon the various magnitudes of the pressure increments.DELTA.P.
said first and second sources of pressurized fluid are oppositely varied by equal pressure increments .DELTA.P upwardly and downwardly, respectively, from a common pressure level Po for causing the arm to reach into various predeterminable predictable specific positions depending directly upon the various magnitudes of the pressure increments.DELTA.P.
16. A fluid-pressure actuatable elongated jointed arm as claimed in claim 14, in which:
said pressurized fluid supply means comprises:
a source of pressurized air at regulated pressure, four pressure-dropping flow resisting components connected to form a four-sided pneumatic bridge network having four corners, with an inlet junction and a vent to atmosphere located at two opposite corners of said bridge and wherein there are two junctions located at the respective other two opposite corners of the bridge forming first and second outlets from the bridge network, said source of pressurized air is connected to said inlet junction for supplying pressurized air at regulated pressure to the bridge network, the first pressure-dropping flow resisting component located between said inlet junction and said first outlet is equal in effect to the second pressure-dropping flow resisting component located between said inlet junction and said second outlet, the third pressure-dropping flow resisting component is located between said first outlet and said vent, the fourth pressure-dropping flow resisting component is located between said second outlet and said vent, said first and second outlets respectively communicate with said first and second actuator strings, and there are control means connected to said third and fourth components for varying their pressure-dropping effects by equal amounts in opposite directions from an initially equal condition.
said pressurized fluid supply means comprises:
a source of pressurized air at regulated pressure, four pressure-dropping flow resisting components connected to form a four-sided pneumatic bridge network having four corners, with an inlet junction and a vent to atmosphere located at two opposite corners of said bridge and wherein there are two junctions located at the respective other two opposite corners of the bridge forming first and second outlets from the bridge network, said source of pressurized air is connected to said inlet junction for supplying pressurized air at regulated pressure to the bridge network, the first pressure-dropping flow resisting component located between said inlet junction and said first outlet is equal in effect to the second pressure-dropping flow resisting component located between said inlet junction and said second outlet, the third pressure-dropping flow resisting component is located between said first outlet and said vent, the fourth pressure-dropping flow resisting component is located between said second outlet and said vent, said first and second outlets respectively communicate with said first and second actuator strings, and there are control means connected to said third and fourth components for varying their pressure-dropping effects by equal amounts in opposite directions from an initially equal condition.
17. A fluid-pressure actuatable elongated jointed arm as claimed in claim 13, in which:
said rigid elements have first, second, third and fourth projections projecting outwardly from the axis and oriented with respect to each other about 90° around the longitudinal axis of the arm, there are first, second, third and fourth pluralities of fluid-inflatable tension actuators respectively joined end-to-end forming first, second, third and fourth strings of tension actuators, said four strings of tension actuators all extend generally parallel with the axis and all are offset from the axis and are located at spaced positions separated from each other about 90° around said longitudinal arm axis, and said first, second, third and fourth strings of tension actuators are fastened to the respective first, second, third and fourth projections of said rigid elements for bending the jointed arm in various directions by varying the internal pressures of the tension actuators in the various strings.
said rigid elements have first, second, third and fourth projections projecting outwardly from the axis and oriented with respect to each other about 90° around the longitudinal axis of the arm, there are first, second, third and fourth pluralities of fluid-inflatable tension actuators respectively joined end-to-end forming first, second, third and fourth strings of tension actuators, said four strings of tension actuators all extend generally parallel with the axis and all are offset from the axis and are located at spaced positions separated from each other about 90° around said longitudinal arm axis, and said first, second, third and fourth strings of tension actuators are fastened to the respective first, second, third and fourth projections of said rigid elements for bending the jointed arm in various directions by varying the internal pressures of the tension actuators in the various strings.
18. A fluid-pressure actuatable elongated jointed arm as claimed in claim 17, in which:
a first pneumatic bridge operates said first and second actuator strings and a second pneumatic bridge operates said third and fourth actuator strings, said first and second pneumatic bridges each comprises:
a source of pressurized air at regulated pressure, four pressure-dropping flow resisting components connected to form a four-sided pneumatic bridge having four corners, with an inlet junction and a vent to atmosphere located at two opposite corners of said bridge and wherein there are two junctions located at the respective other two opposite corners of the bridge forming first and second outlets from the bridge, said source of pressurized air is connected to said inlet junction for supplying pressurized air at regulated pressure to the bridge, the first pressure-dropping flow resisting component located between said inlet junction and said first outlet is equal in effect to the second pressure-dropping flow resisting component located between said inlet junction and said second outlet, the third pressure-dropping flow resisting component is located between said first outlet and said vent, the fourth pressure-dropping flow resisting component is located between said second outlet and said vent, and the first and second outlets of the first bridge communicate with said first and second actuator strings, respectively and the first and second outlets of the second bridge communicate with said third and fourth actuator strings, respectively, and there are control means connected to said third and fourth components in both of said pneumatic bridges for varying the pressure-dropping effects of the third and fourth components in each bridge by equal amounts in opposite directions from an initially equal condition.
a first pneumatic bridge operates said first and second actuator strings and a second pneumatic bridge operates said third and fourth actuator strings, said first and second pneumatic bridges each comprises:
a source of pressurized air at regulated pressure, four pressure-dropping flow resisting components connected to form a four-sided pneumatic bridge having four corners, with an inlet junction and a vent to atmosphere located at two opposite corners of said bridge and wherein there are two junctions located at the respective other two opposite corners of the bridge forming first and second outlets from the bridge, said source of pressurized air is connected to said inlet junction for supplying pressurized air at regulated pressure to the bridge, the first pressure-dropping flow resisting component located between said inlet junction and said first outlet is equal in effect to the second pressure-dropping flow resisting component located between said inlet junction and said second outlet, the third pressure-dropping flow resisting component is located between said first outlet and said vent, the fourth pressure-dropping flow resisting component is located between said second outlet and said vent, and the first and second outlets of the first bridge communicate with said first and second actuator strings, respectively and the first and second outlets of the second bridge communicate with said third and fourth actuator strings, respectively, and there are control means connected to said third and fourth components in both of said pneumatic bridges for varying the pressure-dropping effects of the third and fourth components in each bridge by equal amounts in opposite directions from an initially equal condition.
19. A fluid-actuatable elongated jointed arm comprising:
a support for the arm having first and second spaced fastening points, a first rigid link extending longitudinally along the longitudinal axis of the arm, said first link being pivotally mounted to said support at a first pivot position intermediate said first and second spaced fastening points, first and second pneumatically inflatable tension actuators positioned on opposite sides of said link and each having an inlet end and an outlet end, the inlet end of the first actuator being connected to the first fastening point, the outlet end of the first actuator blocked and being connected to said link at a third fastening point remote from said pivot mounting, the inlet end of the second actuator being connected to the second fastening point, the outlet end of the second actuator being blocked and being connected to said link at a fourth fastening point remote from said pivot mounting, a second rigid link extending longitudinally along the longitudinal axis of the arm pivotally mounted to the arm at a second pivot position remote from said first pivot positions, fifth and sixth spaced fastening points on said first link on opposite sides of said second pivot position and each being spaced from said second pivot position, third and fourth pneumatically inflatable tension actuators positioned on opposite sides of said second link and each having an inlet end and an outlet end, the inlet end of the third actuator being connected to the fifth fastening point, the outlet end of the third actuator being blocked and being connected to said second link at a seventh fastening point remote from said second pivot position, the inlet end of the fourth actuator being connected to the sixth fastening point, and the outlet end of the fourth actuator being blocked and being connected to said second link at an eighth fastening point remote from said second pivot connection.
a support for the arm having first and second spaced fastening points, a first rigid link extending longitudinally along the longitudinal axis of the arm, said first link being pivotally mounted to said support at a first pivot position intermediate said first and second spaced fastening points, first and second pneumatically inflatable tension actuators positioned on opposite sides of said link and each having an inlet end and an outlet end, the inlet end of the first actuator being connected to the first fastening point, the outlet end of the first actuator blocked and being connected to said link at a third fastening point remote from said pivot mounting, the inlet end of the second actuator being connected to the second fastening point, the outlet end of the second actuator being blocked and being connected to said link at a fourth fastening point remote from said pivot mounting, a second rigid link extending longitudinally along the longitudinal axis of the arm pivotally mounted to the arm at a second pivot position remote from said first pivot positions, fifth and sixth spaced fastening points on said first link on opposite sides of said second pivot position and each being spaced from said second pivot position, third and fourth pneumatically inflatable tension actuators positioned on opposite sides of said second link and each having an inlet end and an outlet end, the inlet end of the third actuator being connected to the fifth fastening point, the outlet end of the third actuator being blocked and being connected to said second link at a seventh fastening point remote from said second pivot position, the inlet end of the fourth actuator being connected to the sixth fastening point, and the outlet end of the fourth actuator being blocked and being connected to said second link at an eighth fastening point remote from said second pivot connection.
20. A fluid-actuatable elongated jointed arm as claimed in claim 19, in which:
each of said pivot mountings comprises a peg in a groove pivot.
each of said pivot mountings comprises a peg in a groove pivot.
21. A fluid-actuatable elongated jointed arm as claimed in claim 19, in which:
pressurized fluid control means communicates with the inlet ends of the first, second, third and fourth actuators for inflating said first and second actuators, respectively, and for inflating said third and fourth actuators, respectively, with pressurized fluid controllably varying by equal pressure increments .DELTA.P in opposite directions from a common pressure level Po for causing the jointed arm to move into various positions coming to rest at various predetermined predictable positions depending directly upon the various specific values of the pressure increments.DELTA.P.
pressurized fluid control means communicates with the inlet ends of the first, second, third and fourth actuators for inflating said first and second actuators, respectively, and for inflating said third and fourth actuators, respectively, with pressurized fluid controllably varying by equal pressure increments .DELTA.P in opposite directions from a common pressure level Po for causing the jointed arm to move into various positions coming to rest at various predetermined predictable positions depending directly upon the various specific values of the pressure increments.DELTA.P.
22. A fluid-pressure actuated elongated jointed member having a longitudinal axis and capable of being moved in various controlled directions, comprising:
a plurality of rigid elements located at respective positions spaced along said axis, each of said elements extending across the axis and having first and second projections projecting outwardly on opposite sides of the axis, all of said first projections being on a first side of said axis and all of said second projections being on the second side of said axis, said second side being opposite to said first side, each of said elements being oriented generally perpendicular to the neighbouring portion of the longitudinal axis at the respective position where the element crosses the axis, a plurality of compression-carrying links positioned concentrically along the axis, respective ones of said links extending between successive elements, each link having a pivotal relationship with the adjacent element, said compression-carrying links comprising a plurality of compressive air springs or air actuators of generally oblate form, said air springs being constructed so that a decrease of length corresponds to a decrease in internal pressurized volume, first and second pluralities of fluid-inflatable tension actuators, each of said tension actuators having an inlet end and an outlet end, the tension actuators of the first plurality being joined end-to-end for forming a first inflatable string with the outlet end of each actuator in said first string communicating with the inlet end of the next actuator in said first string, and with the outlet end of the last actuator in said first string being blocked, the tension actuators of the second plurality being joined end-to-end for forming a second inflatable string with the outlet end of each actuator in said second string communicating with the inlet end of the next actuator in said second string, and with the outlet end of the last actuator in said second string being blocked, the first string of tension actuators extending generally parallel with said axis and being offset from said axis on the first side of said axis, the second string of tension actuators extending generally parallel with said axis and being offset from said axis on the second side of said axis, said first string of tension actuators being fastened to the first projections of said elements with respective fastening connections being located near ends of tension actuators in said first string, and said second string of tension actuators being fastened to the second projections of said elements with each respective fastening collection being located near ends of tension actuators in said second string.
a plurality of rigid elements located at respective positions spaced along said axis, each of said elements extending across the axis and having first and second projections projecting outwardly on opposite sides of the axis, all of said first projections being on a first side of said axis and all of said second projections being on the second side of said axis, said second side being opposite to said first side, each of said elements being oriented generally perpendicular to the neighbouring portion of the longitudinal axis at the respective position where the element crosses the axis, a plurality of compression-carrying links positioned concentrically along the axis, respective ones of said links extending between successive elements, each link having a pivotal relationship with the adjacent element, said compression-carrying links comprising a plurality of compressive air springs or air actuators of generally oblate form, said air springs being constructed so that a decrease of length corresponds to a decrease in internal pressurized volume, first and second pluralities of fluid-inflatable tension actuators, each of said tension actuators having an inlet end and an outlet end, the tension actuators of the first plurality being joined end-to-end for forming a first inflatable string with the outlet end of each actuator in said first string communicating with the inlet end of the next actuator in said first string, and with the outlet end of the last actuator in said first string being blocked, the tension actuators of the second plurality being joined end-to-end for forming a second inflatable string with the outlet end of each actuator in said second string communicating with the inlet end of the next actuator in said second string, and with the outlet end of the last actuator in said second string being blocked, the first string of tension actuators extending generally parallel with said axis and being offset from said axis on the first side of said axis, the second string of tension actuators extending generally parallel with said axis and being offset from said axis on the second side of said axis, said first string of tension actuators being fastened to the first projections of said elements with respective fastening connections being located near ends of tension actuators in said first string, and said second string of tension actuators being fastened to the second projections of said elements with each respective fastening collection being located near ends of tension actuators in said second string.
23. A fluid-pressure actuated elongated jointed member as in claim 22, whose compression-carrying links comprise:
a plurality of compressive air springs of generally oblate form, said air springs completely enveloping the tension actuators contained therein.
and where the pressure supplies for the tension actuators operate so that Po ? .DELTA.P is measured relative to the internal pressure of the compressive air springs or air-actuators.
a plurality of compressive air springs of generally oblate form, said air springs completely enveloping the tension actuators contained therein.
and where the pressure supplies for the tension actuators operate so that Po ? .DELTA.P is measured relative to the internal pressure of the compressive air springs or air-actuators.
24. A fluid-pressure actuated elongated jointed member having a longitudinal axis and capable of being moved about in various controlled directions, comprising:
a plurality of rigid elements extending across the axis at spaced positions along the axis, forming a succession of such elements, a plurality of fluid-actuatable tension actuators, each of said tension actuators having an inflatable flexible bladder extending between two spaced ends and said ends of each actuator having a passage therein providing communication with the interior of the bladder through each end, said tension actuators being arranged in communication end-to-end forming first and second strings of tension actuators, said first and second strings being positioned on opposite sides of said axis with respective tension actuators so connected to said rigid elements as to form pairs of opposed tension actuators between successive rigid elements, and compression-carrying means positioned concentrically with respect to the axis and between successive rigid elements so as to provide pivotal joints between successive rigid elements.
a plurality of rigid elements extending across the axis at spaced positions along the axis, forming a succession of such elements, a plurality of fluid-actuatable tension actuators, each of said tension actuators having an inflatable flexible bladder extending between two spaced ends and said ends of each actuator having a passage therein providing communication with the interior of the bladder through each end, said tension actuators being arranged in communication end-to-end forming first and second strings of tension actuators, said first and second strings being positioned on opposite sides of said axis with respective tension actuators so connected to said rigid elements as to form pairs of opposed tension actuators between successive rigid elements, and compression-carrying means positioned concentrically with respect to the axis and between successive rigid elements so as to provide pivotal joints between successive rigid elements.
25. A jointed member as claimed in claim 24, in which:
said compression-carrying means are pivotal links.
said compression-carrying means are pivotal links.
26. A fluid-pressure actuated elongated jointed member as claimed in claim 25, in which:
said pivotal links provide swinging movement in three dimensions, said tension actuators are arranged in communication end-to-end forming third and fourth strings of tension actuators, said third and fourth strings are positioned on opposite sides of said axis with respective tension actuators of said third and fourth strings so connected to said rigid elements as to form pairs of opposed tension actuators between successive rigid elements, and said first, second, third and fourth strings are arranged in order first, second, third and fourth around said axis for enabling movement of said elongated jointed member in three dimensions of movement by controllably inflating said first, second, third and fourth strings of tension actuators.
said pivotal links provide swinging movement in three dimensions, said tension actuators are arranged in communication end-to-end forming third and fourth strings of tension actuators, said third and fourth strings are positioned on opposite sides of said axis with respective tension actuators of said third and fourth strings so connected to said rigid elements as to form pairs of opposed tension actuators between successive rigid elements, and said first, second, third and fourth strings are arranged in order first, second, third and fourth around said axis for enabling movement of said elongated jointed member in three dimensions of movement by controllably inflating said first, second, third and fourth strings of tension actuators.
27. A fluid-pressure actuated elongated jointed member as claimed in claim 24, further comprising:
another plurality of fluid actuatable tension actuators, each of said tension actuators of said another plurality having an inflatable flexible bladder extending between two spaced ends and said ends of each actuator having a passage therein providing communication with the interior of the bladder through each end, said tension actuators of said another plurality being arranged in communication end-to-end forming third and fourth strings of tension actuators, said third and fourth strings being positioned on opposite sides of said axis with respective tension actuators of said third and fourth strings so connected to said rigid elements as to form pairs of opposed tension actuators between successive rigid elements, said first, second, third and fourth strings being arranged in order first, second, third and fourth around said axis, said compression-carrying means. providing pivotal joints enabling said rigid elements to swing into various angular positions in three dimensions, and controllable pressurized fluid supply means communicating with the bladders of said first, second, third and fourth strings for moving said elongated jointed member into various positions with three dimensions of movement.
another plurality of fluid actuatable tension actuators, each of said tension actuators of said another plurality having an inflatable flexible bladder extending between two spaced ends and said ends of each actuator having a passage therein providing communication with the interior of the bladder through each end, said tension actuators of said another plurality being arranged in communication end-to-end forming third and fourth strings of tension actuators, said third and fourth strings being positioned on opposite sides of said axis with respective tension actuators of said third and fourth strings so connected to said rigid elements as to form pairs of opposed tension actuators between successive rigid elements, said first, second, third and fourth strings being arranged in order first, second, third and fourth around said axis, said compression-carrying means. providing pivotal joints enabling said rigid elements to swing into various angular positions in three dimensions, and controllable pressurized fluid supply means communicating with the bladders of said first, second, third and fourth strings for moving said elongated jointed member into various positions with three dimensions of movement.
28. A fluid pressure actuated elongated member having a longitudinal axis and capable off being moved about in various controlled directions, comprising:
a plurality of rigid elements extending across the axis at spaced positions along the axis, forming a succession of such elements, a plurality of fluid-actuatable tension actuators, each of said tension actuators having an inflatable flexible bladder extending between two spaced ends and said ends of each actuator having a passage therein providing communication with the interior of the bladder through each end, said tension actuators being arranged in communication end-to-end forming first and second strings of tension actuators, said first and second strings being positioned on opposite sides of said axis with respective tension actuators so connected to said rigid elements as to form pairs of opposed tension actuators between successive rigid elements, and compression-carrying means positioned concentrically with respect to the axis and between successive rigid elements so as to provide pivotal joints between successive rigid elements, said compression-carrying means being bendable.
a plurality of rigid elements extending across the axis at spaced positions along the axis, forming a succession of such elements, a plurality of fluid-actuatable tension actuators, each of said tension actuators having an inflatable flexible bladder extending between two spaced ends and said ends of each actuator having a passage therein providing communication with the interior of the bladder through each end, said tension actuators being arranged in communication end-to-end forming first and second strings of tension actuators, said first and second strings being positioned on opposite sides of said axis with respective tension actuators so connected to said rigid elements as to form pairs of opposed tension actuators between successive rigid elements, and compression-carrying means positioned concentrically with respect to the axis and between successive rigid elements so as to provide pivotal joints between successive rigid elements, said compression-carrying means being bendable.
29. A fluid-pressure actuated elongated jointed member having a longitudinal axis and capable of being moved about in various controlled directions, comprising:
a plurality of rigid elements extending across the axis at spaced positions along the axis, forming a succession of such elements, a plurality of fluid-actuatable tension actuators, each of said tension actuators having an inflatable flexible bladder extending between two spaced ends and said ends of each actuator having a passage therein providing communication with the interior of the bladder through each end, said tension actuators being arranged in communication end-to-end forming first and second strings of tension actuators, said first and second strings being positioned on opposite sides of said axis with respective tension actuators so connected to said rigid elements as to form pairs of opposed tension actuators between successive rigid elements, and compression-carrying means positioned concentrically with respect to the axis and between successive rigid elements so as to provide pivotal joints between successive rigid elements, said compression-carrying means being compression actuators positioned between the opposed pairs of tension actuators.
a plurality of rigid elements extending across the axis at spaced positions along the axis, forming a succession of such elements, a plurality of fluid-actuatable tension actuators, each of said tension actuators having an inflatable flexible bladder extending between two spaced ends and said ends of each actuator having a passage therein providing communication with the interior of the bladder through each end, said tension actuators being arranged in communication end-to-end forming first and second strings of tension actuators, said first and second strings being positioned on opposite sides of said axis with respective tension actuators so connected to said rigid elements as to form pairs of opposed tension actuators between successive rigid elements, and compression-carrying means positioned concentrically with respect to the axis and between successive rigid elements so as to provide pivotal joints between successive rigid elements, said compression-carrying means being compression actuators positioned between the opposed pairs of tension actuators.
30. A fluid-pressure actuated elongated jointed member having a longitudinal axis and capable of being moved about in various controlled directions comprising:
a plurality of rigid elements extending across the axis at spaced positions along the axis, forming a succession of such elements, a plurality of fluid-actuatable tension actuators, each of said tension actuators having an inflatable flexible bladder extending between two spaced ends and said ends of each actuator having a passage therein providing communication with the interior of the bladder through each end, said tension actuators being arranged in communication end-to-end forming first and second strings of tension actuators, said first and second strings being positioned on opposite sides of said axis with respective tension actuators so connected to said rigid elements as to form pairs of opposed tension actuators between successive rigid elements, and compression-carrying means positioned concentrically with respect to the axis and between successive rigid elements so as to provide pivotal joints between successive rigid elements, said compression-carrying means are compression actuators each having an inflatable flexible bladder, and the bladder of each compression actuator encircles a pair of opposed tension actuators.
a plurality of rigid elements extending across the axis at spaced positions along the axis, forming a succession of such elements, a plurality of fluid-actuatable tension actuators, each of said tension actuators having an inflatable flexible bladder extending between two spaced ends and said ends of each actuator having a passage therein providing communication with the interior of the bladder through each end, said tension actuators being arranged in communication end-to-end forming first and second strings of tension actuators, said first and second strings being positioned on opposite sides of said axis with respective tension actuators so connected to said rigid elements as to form pairs of opposed tension actuators between successive rigid elements, and compression-carrying means positioned concentrically with respect to the axis and between successive rigid elements so as to provide pivotal joints between successive rigid elements, said compression-carrying means are compression actuators each having an inflatable flexible bladder, and the bladder of each compression actuator encircles a pair of opposed tension actuators.
31. A jointed member as claimed in claim 30, in which:
the bladder of each compression actuator has generally the shape of a tire inner tube.
the bladder of each compression actuator has generally the shape of a tire inner tube.
32. A fluid-pressure actuated elongated jointed member as claimed in claim 30, in which:
the flexible inflatable bladders of the compression actuators encircle said first and second strings of tension actuators, and the flexible inflatable bladders of the compression actuators serve as the skin of the jointed member.
the flexible inflatable bladders of the compression actuators encircle said first and second strings of tension actuators, and the flexible inflatable bladders of the compression actuators serve as the skin of the jointed member.
33. A fluid-pressure actuated elongated jointed member as claimed in claim 30, in which:
each of said rigid elements has a perimeter, the flexible inflatable bladders of the compression actuators encircle said first and second strings of tension actuators and are connected to the perimeters of said rigid elements, the flexible inflatable bladders of the compression actuators serve as the skin of the jointed member, and said rigid elements include means providing communication between the flexible inflatable bladders of the compression actuators for enabling their simultaneous inflation and deflation.
each of said rigid elements has a perimeter, the flexible inflatable bladders of the compression actuators encircle said first and second strings of tension actuators and are connected to the perimeters of said rigid elements, the flexible inflatable bladders of the compression actuators serve as the skin of the jointed member, and said rigid elements include means providing communication between the flexible inflatable bladders of the compression actuators for enabling their simultaneous inflation and deflation.
34. A fluid-pressure actuated elongated jointed member as claimed in claim 30, in which:
said elongated jointed member has a skin, the flexible inflatable bladders of the compression actuators encircle said first and second strings of tension actuators, and the flexible inflatable bladders of the compression actuators are associated with the skin of said elongated jointed member.
said elongated jointed member has a skin, the flexible inflatable bladders of the compression actuators encircle said first and second strings of tension actuators, and the flexible inflatable bladders of the compression actuators are associated with the skin of said elongated jointed member.
35. A fluid-pressure actuated elongated jointed member having a longitudinal axis and capable of being moved about in various controlled directions comprising:
a plurality of rigid elements extending across the axis at spaced positions along the axis, forming a succession of such elements, a plurality of fluid-actuatable tension actuators, each of said tension actuators having an inflatable flexible bladder extending between two spaced ends and said ends of each actuator having a passage therein providing communication with the interior of the bladder through each end, said tension actuators being arranged in communication end-to-end forming first and second strings of tension actuators, said first and second strings being positioned on opposite sides of said axis with respective tension actuators so connected to said rigid elements as to form pairs of opposed tension actuators between successive rigid elements, and compression-carrying means positioned concentrically with respect to the axis and between successive rigid elements so as to provide pivotal joints between successive rigid elements, said compression-carrying means are compression actuators each having an inflatable flexible bladder, and the bladder of each compression actuator has generally an oblate shape.
a plurality of rigid elements extending across the axis at spaced positions along the axis, forming a succession of such elements, a plurality of fluid-actuatable tension actuators, each of said tension actuators having an inflatable flexible bladder extending between two spaced ends and said ends of each actuator having a passage therein providing communication with the interior of the bladder through each end, said tension actuators being arranged in communication end-to-end forming first and second strings of tension actuators, said first and second strings being positioned on opposite sides of said axis with respective tension actuators so connected to said rigid elements as to form pairs of opposed tension actuators between successive rigid elements, and compression-carrying means positioned concentrically with respect to the axis and between successive rigid elements so as to provide pivotal joints between successive rigid elements, said compression-carrying means are compression actuators each having an inflatable flexible bladder, and the bladder of each compression actuator has generally an oblate shape.
36. A fluid-pressure actuated elongated jointed member as claimed in claim 35, in which:
said tension actuators are arranged in communication end-to-end forming third and fourth strings of tension actuators, said third and fourth strings are positioned on opposite sides of said axis with respective tension actuators of said third and fourth strings so connected to said rigid elements as to form pairs of opposed tension actuators between successive rigid elements, and said first, second, third and fourth strings of tension actuators are arranged in order first, second, third and fourth around said axis for enabling movement of said elongated jointed member in three dimensions of movement by controllably inflating said first, second, third and fourth strings of tension actuators.
said tension actuators are arranged in communication end-to-end forming third and fourth strings of tension actuators, said third and fourth strings are positioned on opposite sides of said axis with respective tension actuators of said third and fourth strings so connected to said rigid elements as to form pairs of opposed tension actuators between successive rigid elements, and said first, second, third and fourth strings of tension actuators are arranged in order first, second, third and fourth around said axis for enabling movement of said elongated jointed member in three dimensions of movement by controllably inflating said first, second, third and fourth strings of tension actuators.
37. A fluid-pressure actuated elongated jointed member having a longitudinal axis and capable of being moved about in various controlled directions, comprising:
a plurality of rigid elements extending across the axis at spaced positions along the axis, forming a succession of such elements, a plurality of fluid-actuatable tension actuators, each of said tension actuators having an inflatable flexible bladder extending between two spaced ends and said ends of each actuator having a passage therein providing communication with the interior of the bladder through each end, said tension actuators being arranged in communication end-to-end forming first and second strings of tension actuators, said first and second strings being positioned on opposite sides of said axis with respective tension actuators so connected to said rigid elements as to form pairs of opposed tension actuators between successive rigid elements, and compression-carrying means positioned concentrically with respect to the axis and between successive rigid elements so as to provide pivotal joints between successive rigid elements, said compression-carrying means are compression actuators each having an inflatable flexible bladder, and the bladder of each compression actuator has generally toroidal shape.
a plurality of rigid elements extending across the axis at spaced positions along the axis, forming a succession of such elements, a plurality of fluid-actuatable tension actuators, each of said tension actuators having an inflatable flexible bladder extending between two spaced ends and said ends of each actuator having a passage therein providing communication with the interior of the bladder through each end, said tension actuators being arranged in communication end-to-end forming first and second strings of tension actuators, said first and second strings being positioned on opposite sides of said axis with respective tension actuators so connected to said rigid elements as to form pairs of opposed tension actuators between successive rigid elements, and compression-carrying means positioned concentrically with respect to the axis and between successive rigid elements so as to provide pivotal joints between successive rigid elements, said compression-carrying means are compression actuators each having an inflatable flexible bladder, and the bladder of each compression actuator has generally toroidal shape.
38. A fluid-pressure actuated elongated jointed member as claimed in claim 37, in which:
the toroidal shaped bladder of each compression actuator encircles a pair of opposed tension actuators.
the toroidal shaped bladder of each compression actuator encircles a pair of opposed tension actuators.
39. A fluid-pressure actuated elongated jointed member as claimed in claim 37, in which:
said tension actuators are arranged in communication end-to-end forming third and fourth strings of tension actuators, said third and fourth strings are positioned on opposite sides of said axis with respective tension actuators of said third and fourth strings so connected to said rigid elements as to form pairs of opposed tension actuators between successive rigid elements, said first, second, third and fourth strings of tension actuators are arranged in order around said axis for enabling movement of said elongated member in three dimensions of movement by controllably inflating said first, second, third and fourth strings of tension actuators, and the toroidal shaped bladder of each compression actuator encircles a pair of opposed tension actuators of said first and second string and encircles a pair of opposed tension actuators of said third and fourth string.
said tension actuators are arranged in communication end-to-end forming third and fourth strings of tension actuators, said third and fourth strings are positioned on opposite sides of said axis with respective tension actuators of said third and fourth strings so connected to said rigid elements as to form pairs of opposed tension actuators between successive rigid elements, said first, second, third and fourth strings of tension actuators are arranged in order around said axis for enabling movement of said elongated member in three dimensions of movement by controllably inflating said first, second, third and fourth strings of tension actuators, and the toroidal shaped bladder of each compression actuator encircles a pair of opposed tension actuators of said first and second string and encircles a pair of opposed tension actuators of said third and fourth string.
40. A fluid-pressure actuated elongated jointed member having a longitudinal axis and capable of being moved about in various controlled directions, comprising;
a plurality of rigid elements extending across the axis at spaced positions along the axis, forming a succession of such elements, a plurality of fluid-actuable tension actuators, each of said tension actuators having an inflatable flexible bladder extending between two spaced ends and said ends of each actuator having a passage therein providing communication with the interior of the bladder through each end, said tension actuators being arranged in communication end-to-end forming first and second strings of tension actuators, said first and second strings being positioned on opposite sides of said axis with respective tension actuators so connected to said rigid elements as to form pairs of opposed tension actuators between successive rigid elements, and compression-carrying means positioned concentrically with respect to the axis and between successive rigid elements so as to provide pivotal joints between successive rigid elements, said compression-carrying means are compression actuators chamber, and said inflatable chambers are in communication with each other for enabling said compression actuators to be deflated for collapsing the jointed member upon concurrent deflation of all tension actuators so to permit compact storage of said jointed member.
a plurality of rigid elements extending across the axis at spaced positions along the axis, forming a succession of such elements, a plurality of fluid-actuable tension actuators, each of said tension actuators having an inflatable flexible bladder extending between two spaced ends and said ends of each actuator having a passage therein providing communication with the interior of the bladder through each end, said tension actuators being arranged in communication end-to-end forming first and second strings of tension actuators, said first and second strings being positioned on opposite sides of said axis with respective tension actuators so connected to said rigid elements as to form pairs of opposed tension actuators between successive rigid elements, and compression-carrying means positioned concentrically with respect to the axis and between successive rigid elements so as to provide pivotal joints between successive rigid elements, said compression-carrying means are compression actuators chamber, and said inflatable chambers are in communication with each other for enabling said compression actuators to be deflated for collapsing the jointed member upon concurrent deflation of all tension actuators so to permit compact storage of said jointed member.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US82878686A | 1986-02-12 | 1986-02-12 | |
| US828,786 | 1986-02-12 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1280785C true CA1280785C (en) | 1991-02-26 |
Family
ID=25252747
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 529523 Expired CA1280785C (en) | 1986-02-12 | 1987-02-11 | Method and system employing strings of opposed air- inflatable tension actuators in jointed arms, legs, beams and columns for controlling theirmovements |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1280785C (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102011107580A1 (en) | 2011-07-16 | 2013-01-17 | Festo Ag & Co. Kg | Bellows for actuator, has support that is arranged in intermediate space to mutually decouple wall layers so that relative movement of bellows wall transversely to thickness direction is enabled |
| CN110998104A (en) * | 2017-05-31 | 2020-04-10 | 哈佛大学董事会 | Textile actuator |
-
1987
- 1987-02-11 CA CA 529523 patent/CA1280785C/en not_active Expired
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102011107580A1 (en) | 2011-07-16 | 2013-01-17 | Festo Ag & Co. Kg | Bellows for actuator, has support that is arranged in intermediate space to mutually decouple wall layers so that relative movement of bellows wall transversely to thickness direction is enabled |
| DE102011107580B4 (en) * | 2011-07-16 | 2015-02-05 | Festo Ag & Co. Kg | Bellows and method of making a bellows |
| CN110998104A (en) * | 2017-05-31 | 2020-04-10 | 哈佛大学董事会 | Textile actuator |
| CN110998104B (en) * | 2017-05-31 | 2022-07-05 | 哈佛大学董事会 | Textile actuator |
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