U.S. patent application number 12/615897 was filed with the patent office on 2010-05-13 for robotic linkage.
This patent application is currently assigned to Intuitive Surgical, Inc.. Invention is credited to Joshua T. Oen, Christoph Matthias Pistor.
Application Number | 20100116080 12/615897 |
Document ID | / |
Family ID | 42163979 |
Filed Date | 2010-05-13 |
United States Patent
Application |
20100116080 |
Kind Code |
A1 |
Pistor; Christoph Matthias ;
et al. |
May 13, 2010 |
ROBOTIC LINKAGE
Abstract
Methods and apparatus for manufacturing and controlling an
elongate robotic instrument, or robotic endoscope, are provided
which may include any number of features. One feature is a robotic
link that can be easily manufactured and can withstand the forces
related to use within a robotic instrument. Another feature is a
joint on the link that increases compressive strength and minimizes
stress between links. Yet another feature is an elongate robotic
instrument that is constructed from a single type of link.
Inventors: |
Pistor; Christoph Matthias;
(Mountain View, CA) ; Oen; Joshua T.; (Fremont,
CA) |
Correspondence
Address: |
PATENT DEPT;INTUITIVE SURGICAL, INC
1266 KIFER RD, BUILDING 101
SUNNYVALE
CA
94086
US
|
Assignee: |
Intuitive Surgical, Inc.
Synnyvale
CA
|
Family ID: |
42163979 |
Appl. No.: |
12/615897 |
Filed: |
November 10, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61113453 |
Nov 11, 2008 |
|
|
|
Current U.S.
Class: |
74/490.05 ;
264/334 |
Current CPC
Class: |
B25J 9/0012 20130101;
A61B 1/055 20130101; A61B 34/30 20160201; A61B 2034/301 20160201;
Y10T 74/20329 20150115; B25J 18/06 20130101; A61B 1/0055
20130101 |
Class at
Publication: |
74/490.05 ;
264/334 |
International
Class: |
B25J 18/06 20060101
B25J018/06; B25J 17/00 20060101 B25J017/00; B29C 41/42 20060101
B29C041/42 |
Claims
1. A robotic link, comprising: a link having an outer wall surface
and an inner wall surface; a pair of outer hinge portions on a
first end of the link, each outer hinge portion having an inner
bearing surface positioned between the inner wall surface and an
outer ear; and a pair of inner hinge portions on a second end of
the link, each inner hinge portion having an outer bearing surface
positioned between the outer wall surface and an inner ear.
2. The robotic link of claim 1 wherein the robotic link comprises a
polymer.
3. The robotic link of claim 1 wherein each of the pair of outer
hinge portions are diametrically opposed across the link.
4. The robotic link of claim 1 wherein each of the pair of inner
hinge portions are diametrically opposed across the link.
5. The robotic link of claim 1 wherein an axis of rotation of the
outer hinge portions are substantially perpendicular to an axis of
rotation of the inner hinge portions.
6. The robotic link of claim 1 further comprising a guide block
positioned along each inner and outer hinge portion.
7. The robotic link of claim 1 further comprising a tendon guide
positioned integrally within the link along each inner and outer
hinge portion.
8. The robotic link of claim 1 further comprising an integrated
pulley and tendon guide positioned integrally within the link along
each outer hinge portion.
9. The robotic link of claim 1 further comprising an integrated
pulley and tendon guide positioned integrally within the link along
each inner and outer hinge portion.
10. A flexible robotic instrument, comprising: a first link and a
second link each having an outer wall surface and an inner wall
surface; a pair of outer hinge portions disposed on a first end of
each link, each outer hinge portion having an inner bearing surface
positioned between the inner wall surface and an outer ear of each
link; and a pair of inner hinge portions on a second end of each
link, each inner hinge portion having an outer bearing surface
positioned between the outer wall surface and an inner ear of each
link; wherein the outer bearing surface of the first link is
configured to slidably support the outer ear of the second link,
and wherein the inner bearing surface of the second link is
configured to slidably support the inner ear of the first link.
11. The flexible robotic instrument of claim 10 wherein the first
and second links comprise a polymer.
12. The flexible robotic instrument of claim 10 wherein each of the
pair of outer hinge portions are diametrically opposed across the
first and second links.
13. The flexible robotic instrument of claim 10 wherein each of the
pair of inner hinge portions are diametrically opposed across first
and second links.
14. The flexible robotic instrument of claim 10 wherein the outer
hinge portions are substantially perpendicular to the inner hinge
portions.
15. The flexible robotic instrument of claim 10 further comprising
a guide block positioned along each inner and outer hinge
portion.
16. The flexible robotic instrument of claim 10 further comprising
a tendon guide positioned integrally within the first and second
links along each inner and outer hinge portion.
17. The flexible robotic instrument of claim 10 further comprising
an integrated pulley and tendon guide positioned integrally within
the first and second links along each outer hinge portion.
18. The flexible robotic instrument of claim 10 further comprising
an integrated pulley and tendon guide positioned integrally within
the first and second links along each inner and outer hinge
portion.
19. The flexible robotic instrument of claim 10 wherein the first
and second links can articulate up to approximately 30 degrees.
20. A method of manufacturing a robotic link comprising:
introducing a polymer into a mold; and recovering from the mold a
link having an outer wall surface and an inner wall surface, a pair
of outer hinge portions on a first end of the link, each outer
hinge portion having an inner bearing surface positioned between
the inner wall surface and an outer ear, the link also having a
pair of inner hinge portions on a second end of the link, each
inner hinge portion having an outer bearing surface positioned
between the outer wall surface and an inner ear.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit under 35 U.S.C. 119 of
U.S. Provisional Patent Application No. 61/113,453, filed Nov. 11,
2008, titled "ROBOTIC LINKAGE", which is herein incorporated by
reference in its entirety.
INCORPORATION BY REFERENCE
[0002] All publications, including patents and patent applications,
mentioned in this specification are herein incorporated by
reference in their entirety to the same extent as if each
individual publication was specifically and individually indicated
to be incorporated by reference.
FIELD OF INVENTION
[0003] The present invention relates generally to elongate robotic
instruments and elongate surgical robots, such as robotic
endoscopes. More particularly, it relates to methods and
apparatuses for manufacturing and forming elongate robotic
instruments.
BACKGROUND
[0004] The forms of elongate robotic instruments vary widely, but
many elongate robotic instruments share the features of a
mechanical, movable structure under some form of control. The
mechanical structure or kinematic chain (analogous to the human
skeleton) of an elongate robotic instrument can be formed from
several links (analogous to human bones), actuators (analogous to
human muscle) and joints between the links, permitting one or more
degrees of freedom of motion of the links. A continuum or
multi-segment elongate robotic instrument can be a continuously
curving device, like an elephant trunk for example. An example of a
continuum or multi-segment elongate robotic instrument is a
snake-like endoscopic device.
[0005] Snake-like endoscopic devices can transfer forces from an
actuator to particular sections of links in the snake-like device
to effect articulation of that section or link. During
articulation, these links are subjected to large stresses that can
result in breakage or failure of the link and thus, failure of the
endoscopic device. These failures typically occur at the weak point
between links, such as at the joints.
[0006] A typical robotic link is made from a metal or alloy, such
as aluminum or stainless steel. The links can be manufactured by
laser cutting tubes, by laser sintering, by metal injection
molding, or other processes as known in the art. Furthermore, a
snake-like endoscopic device can often include several types of
links, such as distal and proximal links for attachment to
actuators, and passive links therebetween. However, manufacturing
elongate robotic devices with these materials, as well as needing
several different types of links for each device can be expensive
and add to the cost of an elongate robotic instrument.
[0007] An elongate robotic instrument, and more particularly a link
that is used to make up the elongate robotic instrument, is
therefore needed that can be manufactured efficiently and
inexpensively while still being able to withstand the stresses
imposed upon it during normal use.
SUMMARY
[0008] In one embodiment, a robotic link is provided comprising a
link having an outer wall surface and an inner wall surface, a pair
of outer hinge portions on a first end of the link, each outer
hinge portion having an inner bearing surface positioned between
the inner wall surface and an outer ear, and a pair of inner hinge
portions on a second end of the link, each inner hinge portion
having an outer bearing surface positioned between the outer wall
surface and an inner ear.
[0009] In some embodiments, the robotic link comprises a polymer.
The robotic link can comprise PEEK, for example.
[0010] In one embodiment, each of the pair of outer hinge portions
are diametrically opposed across the link. In another embodiment,
each of the pair of inner hinge portions are diametrically opposed
across the link. In some embodiments, an axis of rotation of the
outer hinge portions are substantially perpendicular to an axis of
rotation of the inner hinge portions.
[0011] The robotic link can further comprise a guide block
positioned along each inner and outer hinge portion. In some
embodiments, a tendon guide is positioned integrally within the
link along each inner and outer hinge portion. The robotic link can
also comprise an integrated pulley and tendon guide positioned
integrally within the link along each outer hinge portion. In some
embodiments, the robotic link comprises an integrated pulley and
tendon guide positioned integrally within the link along each inner
and outer hinge portion.
[0012] In one embodiment, the robotic link has an outer diameter of
less than or equal to 0.75 inches.
[0013] A flexible robotic instrument is provided, comprising a
first link and a second link each having an outer wall surface and
an inner wall surface, a pair of outer hinge portions disposed on a
first end of each link, each outer hinge portion having an inner
bearing surface positioned between the inner wall surface and an
outer ear of each link, and a pair of inner hinge portions on a
second end of each link, each inner hinge portion having an outer
bearing surface positioned between the outer wall surface and an
inner ear of each link, wherein the outer bearing surface of the
first link is configured to slidably support the outer ear of the
second link, and wherein the inner bearing surface of the second
link is configured to slidably support the inner ear of the first
link.
[0014] In some embodiments, the first and second links comprise a
polymer. The first and second links can comprise PEEK, for
example.
[0015] In one embodiment, an interior volume of the instrument is
sized to accommodate at least two working channels.
[0016] In some embodiments, each of the pair of outer hinge
portions are diametrically opposed across the first and second
links. Similarly, each of the pair of inner hinge portions can be
diametrically opposed across first and second links. In one
embodiment, the outer hinge portions are substantially
perpendicular to the inner hinge portions.
[0017] The flexible robotic instrument can further comprise a guide
block positioned along each inner and outer hinge portion. In some
embodiments, a tendon guide is positioned integrally within the
first and second links along each inner and outer hinge portion. In
other embodiments, the flexible robotic instrument can comprise an
integrated pulley and tendon guide positioned integrally within the
first and second links along each inner and/or outer hinge
portion.
[0018] In one embodiment, the flexible robotic instrument has an
outer diameter of less than or equal to 0.75 inches.
[0019] The flexible robotic instrument can further comprise a
plurality of actuation tendons.
[0020] In one embodiment, the first and second link of the flexible
robotic instrument can articulate up to approximately 30
degrees.
[0021] A method of manufacturing a robotic link is provided,
comprising introducing a polymer into a mold, and recovering from
the mold a link having an outer wall surface and an inner wall
surface, a pair of outer hinge portions on a first end of the link,
each outer hinge portion having an inner bearing surface positioned
between the inner wall surface and an outer ear, the link also
having a pair of inner hinge portions on a second end of the link,
each inner hinge portion having an outer bearing surface positioned
between the outer wall surface and an inner ear.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is a cross sectional view of a robotic link.
[0023] FIG. 2 is an illustration of an elongate robotic
instrument.
[0024] FIGS. 3a-3c are illustrations of a robotic link.
[0025] FIGS. 4a-4b are illustrations of a robotic link.
[0026] FIG. 5 is a schematic illustration of various robotic links
used in an elongate robotic instrument.
[0027] FIGS. 6a-6b illustrate a double knee joint in a robotic
link.
[0028] FIGS. 7a-7b are schematic illustrations of various robotic
links used in an elongate robotic instrument.
[0029] FIG. 8 is a schematic illustration of various robotic links
used in an elongate robotic instrument.
[0030] FIG. 9 shows a factor of safety for different link
designs.
[0031] FIG. 10 shows a factor of safety for aluminum and victrex
link designs.
[0032] FIG. 11 is a bar graph illustrating predicted link strength
vs. testing.
[0033] FIG. 12 is an illustration of a pair of joined robotic
links.
[0034] FIG. 13 is an illustration of a pair of joined robotic
links.
[0035] FIG. 14 is a schematic illustration showing the effect of
guide blocks within a link and vertebra diameter on dead space.
[0036] FIG. 15 is a cross sectional view of a link with a guide
block.
[0037] FIG. 16 is a cross sectional view of a link without a guide
block.
[0038] FIG. 17 illustrates the location of eyelets in a link
without a guide block.
[0039] FIG. 18 illustrates the eyelet distance vs. articulation
angle in an elongate robotic instrument.
[0040] FIGS. 19a-19b illustrates embodiments of a robotic link
without a guide block.
[0041] FIG. 20 shows data from a shape sensor in a 120 degree sweep
of an elongate robotic instrument in the x-plane.
[0042] FIG. 21 shows data from a shape sensor in a sweep of an
elongate robotic instrument in the x, y, and z-planes.
[0043] FIG. 22 shows data from a shape sensor in a 120 degree sweep
of an elongate robotic instrument.
[0044] FIG. 23 illustrates a robotic link without a guide
block.
[0045] FIG. 24 illustrates a robotic link without a guide block and
including a pulley feature.
DETAILED DESCRIPTION
[0046] Aspects of various embodiments include: Dimensioning and
design of the part to make it mass-manufacturable by injection
molding while still withstanding the high compressive loading that
occurs inside robotic endoscopes; Double knee-joint to resolve
compressive loading during articulation; integrated static pulley;
Flat pulley surface to reduce friction; Integrated design of cable
routing features that allows the same part to be used as a segment
boundary and passive link.
[0047] The NOTES Vertebra development had the following design
goals: Provide a max 150 degrees of articulation/seg; 4 active
segments; Min 48 cm active length; 20 mm outside diameter (with
skin); implement 2:1 purchase.
[0048] These goals resulted in the following design constraints and
requirements: Provide room for two lumens; 16 coil tubes;
Air/Water; Light bundle; Camera cable; Eight sense cable; Four
ascension sensors; Maintain vertebrae OD of 0.75 inches; Use
current alternating X-Y config; Use PE for actuation tendons;
Capable to do straight or helix payload. See FIG. 1.
[0049] Based on this the following segment geometry was chosen:
Links limited 30 degrees bend; X-Y pair length 1.12 inch; 150
degrees=5 paired links; Segment length=5.6 inches; Articulated
length=5.6''/seg.times.4 seg=22.4'' (57 cm). See FIG. 2.
[0050] Termination of the actuation coil pipes and the
implementation of the 2:1 purchase is shown in FIGS. 3a-3c.
[0051] Routing of the sense wire was chosen to be at an angle of 45
deg from the actuation cables. See FIGS. 4a-4b.
[0052] Major characteristics of this implementation of the NOTES
(BETA PHASE) vertebra are: Machined aluminum (AL 7075 T6) links
with nickel plating; Three different (Front, Middle, and Back)
boundary links; Implements sense wire routing; PEEK inserts in all
Cable eyelets; Glued two piece rivet to attach links; Decoupling of
cables using swiveling guide block for out-of-plane cable routing.
See FIG. 5.
[0053] After successful testing of the BETA PHASE vertebrae in a
single link compression, in segment compression and in full scope
assemblies the BOM COGS PHASE of NOTES vertebra was developed in
which the focus was in cost reduction. The main emphasis was to
reduce cost by using injection molding instead of machining.
Injection molding requires the use of plastic resin, so the first
exercise was to develop a design that would withstand the
anticipated compressive load.
[0054] After estimating the expected compressive loading the
following concept was presented: Load bearing knee joint. See FIGS.
6a-6b. To minimize stress, the knee joint should include the inner
ear. Design provides a total of 4.times.0.00406 in.sup.2=0.0162
in.sup.2 projected area. Maximum compressive loading is therefore
3081.96 psi. The compressive strength of unreinforced PEEK is
20,000 psi and 30% carbon reinforced PEEK it is 29,000 psi. The
safety factor to compressive failure of the ears is therefore 6.5
and 9.4 respectively.
[0055] The double knee-joint design was possible due to the fact
that the link was now an injection molded component. In addition to
molding the link components, cost savings was realized by
integrating the features of the three different boundary links
(front, middle, and back) into a single boundary link. The initial
design for the molded passive link and boundary link of the BOM
COGS PHASE in comparison to the links of the BETA PHASE is shown in
FIG. 7a-7b.
[0056] The notion of the Front Middle and Back link for the segment
boundary still exists in the BOM COGS design, however these links
are now built up using the same base part and adding the features
with the necessary inserts. An overview of the arrangement of
inserts and link components for the BOM COGS master segment is
shown in FIG. 8.
[0057] To ensure that this new design will fulfill the load bearing
requirements of the NOTES scope application, several Finite Element
studies were performed. The following figures show the results from
these studies. First a comparison of the different designs is shown
assuming all links are made from Aluminum. See FIG. 9. Second the
factor of safety for the molded link design in Al is shown to the
factor of safety of the molded link design in Victrex 90HMF40 is
shown in FIG. 10.
[0058] An overview of the link strength prediction via FEA vs the
actual results from Instron testing after the links had been molded
is shown in FIG. 11.
[0059] After successful link compression, and full scope testing of
the BOM COGS PHASE NOTES vertebra design, a new NOTES design phase
was initiated. For this phase a different vertebra design that
eliminates the need for a PE guide block has been suggested and is
shown in FIGS. 12-13 in comparison to the previous design.
[0060] The main idea is to thread the out-of-plane PE tendons
within the outer circumference of the vertebrae instead of bringing
them into the inner lumen. This design would have the following
advantages: Increase available lumen space (could be used for
extra/larger payload, could lead to a total diameter reduction of
the backbone); Allowing the helix to propagate during assembly more
easily; Avoiding restriction of local slack of the helix during
articulation; Simplifying assembly by giving assemblers access to
all the eyelets from the outside of the backbone; Saving cost by
reducing the assembly part count by two parts (guide block removed
from BOM and long rivet replaced by existing short rivet).
[0061] The potential risks/disadvantages of such a design are:
Control issues due to coupling between out-of-plane and in-plane
cable motion; Increased articulation forces; Reduced strength of
the vertebrae due to material removal at the ear base.
[0062] To show the effect of the no-guide block link design on the
available dead space inside the endoscope, a packing study has been
performed that shows that eliminating the guide blocks results in
the possibility of reducing the vertebra diameter from 0.75'' to
0.7'' while conserving the same amount of dead space. See FIGS.
14-16.
[0063] Based on the link geometry a kinematic analysis was
performed to determine the distance between the out-of-plane PE
eyelets (EarEyelets) and the in-plane eyelets (ActEyelets).
[0064] FIGS. 17-18 show the geometry and the results of the
analysis. The results show that the average value of the sum of the
EarEyelet distance is 0.231192'' with a standard deviation of
0.002441'' over the complete range of articulation from -30 to +30
degrees. The average value of the sum of the ActEyelet distance is
0.494157'' with a standard deviation of 0.005252''.
[0065] Finite Element Analysis showed that the new design has a
Factor of safety that is comparable with the one of the current
design when loaded in compression at 50 lbs. See FIGS. 19a-19b.
[0066] Five no-guide-block design links were prototyped via PolyJet
and built into a segment using standard segment boundary links. The
segment was built using standard coil-pipes and 50 lbs Power Pro
cable for actuation. The segment was outfitted with two ascension
sensors, one in the proximal middle link and the other one in the
distal middle link.
[0067] Initial tests showed that single line actuation of the
segment results in a coupled articulation in the x and y-plane. By
first applying tension to all cables and then applying slightly
more tension in the desired actuation direction, while slightly
releasing tension on the opposing cable, in-plane articulation was
achieved.
[0068] FIGS. 20 through 22 and Table 1 show the Ascension sensor
readings of the distal ascension sensor during such articulations.
In this case, several sweeps from the -x hard stops to +x hard
stops (total of 120 degree).
TABLE-US-00001 TABLE 1 Stddev 1.963595 mm Average -275.013 mm Min
-281.955 mm Max -269.677 mm Range -12.278 mm
[0069] The Ascension data shows a total range of about 12 mm in the
z-coordinate. Some of this variation can be attributed to
noise.
[0070] Due to the fact that the PolyJet prototype material has a
relatively low modulus, the links started to bend ("potato chip")
when the tension in the cables was increased. Therefore, a second
no-guide-block segment was built. For this second segment,
injection molded passive links were modified with holes from next
to the ears into the actuation cable slots. See FIG. 23.
[0071] Another no-guide-block link with straight slots to reduce
cable friction has been designed and it is suggested to prototype
this link in a stronger material to build up a third test
segment.
[0072] Before testing of the design of FIG. 23 was completed, a new
fully integrated design was suggested. This design was named
Universal Link since it integrates all the features that are
necessary for passive links and all the features that are needed in
boundary links are combined into a single link. See FIG. 24. The
main advantages of this design are: Lower tooling cost, only one
link is needed therefore only one tool needs to be made; The pulley
has been integrated and there is no bonding necessary of the pulley
to the link; The pulley has a flat surface instead of a groove
which substantially reduces friction (even in all the previous
designs the pulley was implemented as a static pulley); The pulley
diameter has been increased which again lowers cable friction; The
pulley has been implemented in such a way that derailing of the
cable is impossible, due to the fact that the cable takes the
shortest distance between eyelets; Even under compression/slack of
the cables, the cables do not derail since they are guided and
aligned by the eyelets; All of the features have been implemented
in such a way that the link can be manufactured by injection
molding which reduces the manufacturing cost substantially.
[0073] As for additional details pertinent to the present
invention, materials and manufacturing techniques may be employed
as within the level of those with skill in the relevant art. The
same may hold true with respect to method-based aspects of the
invention in terms of additional acts commonly or logically
employed. Also, it is contemplated that any optional feature of the
inventive variations described may be set forth and claimed
independently, or in combination with any one or more of the
features described herein. Likewise, reference to a singular item,
includes the possibility that there are plural of the same items
present. More specifically, as used herein and in the appended
claims, the singular forms "a," "and," "said," and "the" include
plural referents unless the context clearly dictates otherwise. It
is further noted that the claims may be drafted to exclude any
optional element. As such, this statement is intended to serve as
antecedent basis for use of such exclusive terminology as "solely,"
"only" and the like in connection with the recitation of claim
elements, or use of a "negative" limitation. Unless defined
otherwise herein, all technical and scientific terms used herein
have the same meaning as commonly understood by one of ordinary
skill in the art to which this invention belongs. The breadth of
the present invention is not to be limited by the subject
specification, but rather only by the plain meaning of the claim
terms employed.
* * * * *