U.S. patent application number 09/827503 was filed with the patent office on 2001-08-30 for articulated apparatus for telemanipulator system.
Invention is credited to Brock, David L., Lee, Woojin.
Application Number | 20010018591 09/827503 |
Document ID | / |
Family ID | 31190483 |
Filed Date | 2001-08-30 |
United States Patent
Application |
20010018591 |
Kind Code |
A1 |
Brock, David L. ; et
al. |
August 30, 2001 |
Articulated apparatus for telemanipulator system
Abstract
An articulated apparatus is disclosed that includes a first link
member, a second link member, and a third link member. The second
link member is coupled to the first link member at a proximal end
of the second link member by a first joint having a first axis of
rotation. The third link member is coupled to a distal end of the
second link member by a second joint. The movement of the third
link member with respect to the second link member is governed by
at least one tendon that passes through the first axis of rotation
of the first joint such that movement of the second member with
respect to the first member does not cause movement of the third
member with respect to the second member.
Inventors: |
Brock, David L.; (Natick,
MA) ; Lee, Woojin; (Cambridge, MA) |
Correspondence
Address: |
Samuels, Gauthier & Stevens LLP
Suite 3300
225 Franklin Street
Boston
MA
02110
US
|
Family ID: |
31190483 |
Appl. No.: |
09/827503 |
Filed: |
April 6, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09827503 |
Apr 6, 2001 |
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09746853 |
Dec 21, 2000 |
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|
09746853 |
Dec 21, 2000 |
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09375666 |
Aug 17, 1999 |
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6197017 |
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09375666 |
Aug 17, 1999 |
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09028550 |
Feb 24, 1998 |
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Current U.S.
Class: |
606/130 |
Current CPC
Class: |
G16H 20/40 20180101;
A61B 90/361 20160201; A61B 34/37 20160201; A61B 17/3421 20130101;
A61B 34/77 20160201; A61B 2034/715 20160201; A61B 34/35 20160201;
A61B 34/70 20160201; B25J 3/04 20130101; A61B 34/71 20160201; A61B
2017/2939 20130101; B25J 9/104 20130101; A61B 17/3462 20130101;
A61B 34/30 20160201; G16H 40/67 20180101; A61B 17/00234
20130101 |
Class at
Publication: |
606/130 |
International
Class: |
A61B 019/00 |
Claims
What is claimed is:
1. An articulated apparatus comprising: a first link member; a
second link member coupled to said first link member at a proximal
end of said second link member by a first joint having a first axis
of rotation; and a third link member coupled to a distal end of
said second link member by a second joint, the movement of said
third link member with respect to said second link member being
governed by at least one tendon that passes through said first axis
of rotation of said first joint such that movement of said second
member with respect to said first member does not cause movement of
said third member with respect to said second member.
2. An articulated apparatus as claimed in claim 1, wherein said
apparatus further includes a base portion including drive means for
controlling the movement of each said link member with respect to
other link members.
3. An articulated apparatus as claimed in claim 1, wherein said at
least one tendon includes a cable having a diameter of about
{fraction (80/1000)} inches.
4. An articulated apparatus as claimed in claim 1, wherein at
first, second and third link members may be inserted into a patient
during endoscopic surgery.
5. An articulated apparatus comprising: a first link member; a
second link member coupled to said first link member at a proximal
end of said second link member by a first joint having a first axis
of rotation; and at least one tendon extending through said first
axis of rotation of said first joint such that movement of said
second link member with respect to said first link member is
independent of movement of said at least one tendon with respect to
said first joint, said tendon being movable in a tendon direction
that is transverse to the first axis of rotation to effect movement
of a third link member with respect to said second link member.
6. An articulated apparatus as claimed in claim 5, wherein said
apparatus further includes a second tendon that extends through
said first axis of rotation of said first joint such that movement
of said second link member with respect to said first link member
is independent of movement of said tendons with respect to said
first joint.
7. An articulated apparatus as claimed in claim 5, wherein said
apparatus further includes a base portion including drive means for
controlling the movement of each said link member with respect to
other link members.
8. An articulated apparatus as claimed in claim 5, wherein said at
least one tendon includes a cable having a diameter of about
{fraction (80/1000)} inches.
9. An articulated apparatus as claimed in claim 5, wherein at
first, second and third link members may be inserted into a patient
during endoscopic surgery.
10. An articulated apparatus comprising: a first link member; a
second link member coupled to said first link member at a proximal
end of said second link member by a first joint having a first axis
of rotation; and a plurality of mutually independently
longitudinally movable tendons each extending through said first
axis of rotation of said first joint such that movement of said
second link member with respect to said first link member is
independent of longitudinal movement of said tendons with respect
to said first joint, said tendons being movable in a longitudinal
direction that is transverse to the first axis of rotation to
effect movement of a plurality of distal link members that coupled
to the distal end of said second link member.
11. An articulated apparatus as claimed in claim 10, wherein said
at least some of said serially coupled link members may be
introduced into a patient during endoscopic surgery.
12. An articulated apparatus as claimed in claim 10, wherein said
tendons each include a cable having a diameter of about {fraction
(80/1000)} inches.
13. An articulated apparatus as claimed in claim 10, wherein at
first and second link members may be inserted into a patient during
endoscopic surgery.
14. An articulated apparatus comprising: a first link member; a
second link member coupled to said first link member at a proximal
end of said second link member by a first joint having a first axis
of rotation; and a third link member coupled to a distal end of
said second link member by a second joint, the movement of said
third link member with respect to said second link member being
governed by at least one tendon that passes through said first axis
of rotation of said first joint such that movement of said at least
one tendon with respect to said first joint does not cause movement
of said second link member with respect to said first member.
15. An articulated apparatus as claimed in claim 14, wherein said
at least one tendon includes a cable having a diameter of about
{fraction (80/1000)} inches.
16. An articulated apparatus as claimed in claim 14, wherein at
first, second and third link members may be inserted into a patient
during endoscopic surgery.
Description
[0001] This application is a continuation application of U.S. Ser.
No. 09/746,853 filed Dec. 21, 2000, which is a divisional
application of U.S. Ser. No. 09/375,666 filed Aug. 17, 1999 and now
U.S. Pat. No. 6,197,017, which is a continuation application of
U.S. Ser. No. 09/028,550 filed Feb. 24, 1998, now abandoned.
BACKGROUND OF THE INVENTION
[0002] The invention generally relates to robotics and particularly
relates to telerobotic surgery.
[0003] Telerobotic surgical devices are well suited for use in
performing endoscopic (or minimal access) surgery, as opposed to
conventional surgery where the patient's body cavity is open to
permit the surgeon's hands access to internal organs. Endoscopic
techniques involve performing an operation through small (about 5
mm to 10 mm) skin incisions through which instruments are inserted
for performing the surgical procedure. A video camera may also be
inserted into the patient in the area of the surgical site to view
the procedure. Endoscopic surgery is typically less traumatic than
conventional surgery, in part, due to the significantly reduced
size of the incision. Further, hospitalization periods are shorter
and recovery periods may be quicker when surgery is performed
endoscopically rather than conventionally.
[0004] It is, of course, important that the surgeon have some
feedback from the surgical site, e.g., visual feedback either
through a camera and fiber optic cable, or through real-time
computerized tomography scan imagery. Even with good visualization,
however, the surgeon's tactile and position senses are physically
removed from the operative site rendering the endoscopic procedure
slow and clumsy. Current instrumentation, with forceps, scissors,
etc., inserted into the body at the end of long slender push rods
is not fully satisfactory. The use of such conventional
instrumentation may result in longer operative time, and
potentially higher risks, for example if a ruptured artery cannot
be quickly closed off then significant blood loss may occur.
Moreover, there are limitations on the type and complexity of
procedures that can be performed endoscopically due, in part, to
the limitations on the instruments that may be employed.
[0005] Limited development work has been undertaken to investigate
the use of robots in surgery. The robot at the surgical site,
however, must be small and light enough that it may be easily
manipulated around and inside of the patient, yet strong enough to
perform effective surgery. The controls for the robot must also be
precise and not sloppy. Presently existing telerobotic systems,
using manipulators both with and without haptic feedback, are
generally too bulky and heavy for many endoscopic techniques, or
are too weak and imprecise for surgery.
[0006] There is a need, therefore, for a micro-manipulator that is
strong and precise in its movements, yet is small, light and easily
manipulated.
SUMMARY OF THE INVENTION
[0007] The invention provides an articulated apparatus that
includes a first link member, a second link member, and a third
link member. The second link member is coupled to the first link
member at a proximal end of the second link member by a first joint
having a first axis of rotation. The third link member is coupled
to a distal end of the second link member by a second joint. The
movement of the third link member with respect to the second link
member is governed by at least one tendon that passes through the
first axis of rotation of the first joint such that movement of the
second member with respect to the first member does not cause
movement of the third member with respect to the second member.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The following detailed description of the illustrated
embodiments may be further understood with reference to the
accompanying drawings in which:
[0009] FIG. 1 shows an illustrative view of a system incorporating
the benefits of the invention;
[0010] FIG. 2 shows a diagrammatic representation of the relative
rotational movements of the joints in the system of FIG. 1;
[0011] FIG. 3 shows an illustrative isometric view of the handle
portion of the system of FIG. 1;
[0012] FIG. 4 shows an illustrative top view of the handle portion
shown in FIG. 3 with a portion of the outer housing removed;
[0013] FIG. 5 shows an illustrative side view of the handle portion
shown in FIG. 3 with a portion of the outer housing removed;
[0014] FIGS. 6 through 11 show illustrative sectional views of the
handle portion shown in FIG. 5 taken along lines 6-6 through 11-11
respectively thereof;
[0015] FIGS. 12 and 13 show illustrative side and top views
respectively of the handle axial rotation portion of the system
shown in FIG. 1;
[0016] FIG. 14 shows an illustrative and partially exploded
isometric view of the rotating bearings of FIGS. 12 and 13;
[0017] FIG. 15 shows an illustrative view of the cable collector of
FIGS. 12 and 13 with its housing partially removed;
[0018] FIGS. 16 through 18 show illustrative sectional views of the
cable collector of FIG. 15 taken along lines 16-16 through 18-18
respectively thereof;
[0019] FIG. 19 shows an illustrative side view of the elbow joint
portion of the master robot shown in FIG. 1;
[0020] FIGS. 20 and 21 show illustrative sectional views of the
elbow joint portion shown in FIG. 19 taken along lines 20-20 and
21-21 thereof;
[0021] FIG. 22 shows an illustrative rear view of the elbow joint
of FIG. 19 taken along line 22-22 thereof;
[0022] FIG. 23 is an illustrative front view the base and shoulder
portions of the master robot of FIG. 1;
[0023] FIG. 24 is an illustrative side view of the shoulder portion
of the robot of FIG. 1 taken along line 24-24 of FIG. 23;
[0024] FIG. 25 is a plan view of a portion of the base portion of
FIG. 23 taken along line 25-25 thereof;
[0025] FIGS. 26 and 27 are illustrative top and side views
respectively of the gripper portion of the system of FIG. 1 with
the housing partially removed;
[0026] FIGS. 28-33 are illustrative sectional views of the gripper
portion of FIG. 27 taken along lines 28-28 through 33-33
respectively thereof;
[0027] FIGS. 34 and 35 show operational steps of different
embodiments of systems incorporating the invention;
[0028] FIGS. 36 and 37 show illustrative side views of a portion of
another embodiment of the invention involving a four bar linkage in
two different positions;
[0029] FIG. 38 shows an illustrative isometric view of another
embodiment of a gripper mechanism of a system of the invention;
[0030] FIG. 39 shows an illustrative side view of a portion of the
gripper assembly shown in FIG. 38; and
[0031] FIG. 40 shows an illustrative top view of the portion of the
gripper assembly shown in FIG. 39.
[0032] The drawings are not to scale and are intended to be
illustrative of the operation of various systems of the
invention.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
[0033] The invention provides a micro-manipulator that is suitable
for use in endoscopic surgery. During use, the surgeon should have
the familiarity and surety of experiencing his or her hands within
the patient at the operative site, while the surgeon's hands are
placed within a sensory interface outside of the patient. The
sensory interface, or master robot, precisely reflects the tactile
environment of the robotic hand to the operator's fingers. This
haptic interface electronically connects the surgeon's hand and
wrist position and motion to the micro-manipulator within the
patient. The digital information communicated between the haptic
interface and robotic manipulator is transmitted through the
endoscopic device, whether it be a laparoscope, thoracoscope,
arthroscope, laryngoscope or other minimal access surgical
device.
[0034] Due to the electronic digital interface, it is not required
that the haptic interface and micro-manipulator be mechanically
connected. This permits civilian, as well as military, physicians
to provide care to patients located in remote or potentially
hostile environments via telepresence. Telepresence with
appropriate sensing instruments could permit one surgeon to conduct
operations at different sites (any distance apart) without
traveling. Systems incorporating the invention also permit sterile
isolation of the slave robot at the operation site from the master
robot and surgeon.
[0035] As shown in FIG. 1, a system 10 including benefits of the
invention includes a master robot 12, a central processor 14, and a
slave robot 16. The system may be used by positioning the end
effector tip 18 of the slave robot 16 through a trocar sleeve 20
into a patient 22 during surgery. During use, a surgeon may
manipulate the end effector handle unit 24 of the master robot, to
effect the desired positioning and movement of the grippers on the
tip unit 18 within the patient 22. The system may also include a
fiber optic cable with a camera (not shown) at its distal end
within the surgical site. The fiber optic cable is connected to a
video system (not shown) for viewing the surgical site. The camera
may be mounted on the instrument tip unit 18, or may be positioned
away from the site to provide additional perspective on the
surgical operation. In certain situations, it may be desirable to
provide the camera through an incision other than the one through
which the trocar sleeve 20 and instrument have been inserted into
the patient.
[0036] The master robot 12 includes handles 26, 27 similar to the
scissor handles on a conventional surgical instrument. These
handles may be independently rotated about two joints having a
common axis generally indicated at 28. The pair of handles may then
be rotated about a joint generally indicated at 30 that has an axis
of rotation orthogonally disposed to the axis of rotation of the
other two joints at 23. This structure may then be rotated axially
about an axial joint generally located at 32, which in turn may be
rotated about an elbow joint generally located at 34, a shoulder
joint generally located at 36, and a base rotation joint generally
located at 38. The relative rotational movements of these joints
are diagrammatically depicted in FIG. 2.
[0037] The slave robot 16 includes a base rotation joint 40, a
shoulder rotation joint 42, and an elbow rotation joint 44 each
similar to the joints 38, 36, and 34 of the master robot 12. The
slave robot 16 also includes two free joints 46 and 48 that provide
axial and longitudinal rotation without being connected to any
motors. This permits the arm of the slave robot to freely move
relative the incision point through the trocar generally indicated
at P. The slave robot 16 also includes an axial rotation joint 50
providing axial rotation of the tip unit 18, as well as joints 52
and 54 that provide movement of the grippers both independently and
together. The relative rotational movements of these joints are
also diagrammatically depicted in FIG. 2.
[0038] Significantly, the motors that control the joints proximate
the handle 26 in the master robot 12 are located in the base 58,
and the motors that control the joints in the slave robot 16
proximate the grippers 56, 57 are located in the base 60 of the
slave robot 16. Cables extend from motors in the base up through
each section and joint to control and monitor movement of the
non-free joints as will be discussed further below. This permits
the robots, and in particular the end effector portion of the slave
robot, to be both small and light. In a preferred embodiment, all
of the motors are located in the base of each respective robot.
[0039] As shown in FIGS. 3 through 5, the handles 26, 27 of the
system on FIG. 1 are attached to handle pulleys 62. Cables 64a-64d
extend from the handle pulleys 62 and pass around additional
pulleys within the handle unit 24. The cables 64 then extend toward
the next proximate section of the robot, and eventually terminate
in the base 58. Specifically, and with reference to the sectional
views shown in FIGS. 6 through 11, the cables 64 extend from the
handle pulleys 62 (FIG. 6), then pass around two split level
pulleys 66 (FIG. 7), then around another pulley 68 (FIG. 8) to
bring the cables near a set of four larger diameter pulleys 70
(FIG. 9), and finally to a set of four alignment pulleys 72 (FIG.
10).
[0040] The cables may be formed of any high strength, high
molecular weight polyethylene (or other polymeric) fibers such as
SPECTRA or VECTRAN polymers. The cables may be {fraction (80/1000)}
of an inch in diameter, and may be either two single loop cables
that are fixed to the handle pulleys 62, or may comprise four
separate cables, each of which is fixed to the handle pulleys 62.
The pulleys may be formed of any suitable material, e.g.,
polytetrafluoroethylene (PTFE) and the guide pulleys 66, 68 and 72
may either be independently freely rotating or fixed. The various
portions of pulleys 68 and 72 may also rotate independent of one
another. Pulleys 62 includes two pulleys that may rotated
independent of one another, and pulleys 70 include four pulleys
that may rotated independent of one another. Spacers formed of PTFE
tape may also be inserted between adjacent independently rotating
pulleys, such as is shown between adjacent pulley wheels 70 in FIG.
9. The spacers 71 permit rotation of the pulleys relative each
other with decreased friction, and help maintain placement of the
cables on the pulleys.
[0041] The handle unit 24 provides three degrees of freedom of
movement as follows. When one of the handles 26 is moved relative
the other 27, the pairs of cables 64a and 64c will produce
reciprocal movement, and the pair of cables 64b and 64d will
produce reciprocal movement as may be discerned from FIG. 3. With
reference to FIGS. 3, 5 and 9, however, when the handles are
rotated together about joint 30 which is coincident with the
centers of pulleys 70, the cables 64b and 64d will move together in
a direction opposite the direction of movement of cables 64a and
64c See FIG. 9. A surgeon, therefore, may hold the handles 26, 27
with his or her thumb and forefinger, and may place a third finger
against the handle unit at the location of the housing generally
indicated at A in FIG. 3. In alternative embodiments, the cables
may be run in a variety of ways, for example the placement of
cables 64c and 64d may be swapped on pulleys 70, 72 and 74.
[0042] As shown in FIGS. 12 and 13, the axial rotational joint 32
on the master robot 12 of FIG. 1, is driven by two cables 74a and
74b The cables extend radially outwardly from one robot arm member
76, around one set of pulleys each positioned over another arm
member 78 fixed to the arm member 76, and then are attached to an
adjoining arm member 80. By rotating the arm member 80 with respect
to the arm member 76, the cables 74a and 74b will alternately move
in opposite directions. A safety tie strap 82 may be fixed to each
of the arms 78 and 80 to prevent rotation beyond a certain range.
This will prevent damage to the cables from over rotation since the
cables 64 that extend from the handle unit 24 run through the
center of the arm members 78 and 80 as shown. The arm member 80
also includes internal rotational bearing 83 through which the
cables pass as shown in FIG. 14. FIG. 14 illustrates the rotational
relationship of the cable arms 78 and 80 (shown slightly spaced
apart. The positioning of the cables 64 in the center of the
sections 80 and 78 permits the section 80 to be rotated with
respect to section 78 about joint 32 without significant attendant
movement of the cables 64.
[0043] As shown in phantom in FIG. 12, a cable collector 84 is
located within the robot section 76. The cable collector 84
receives the cables 64 that are positioned within the center of the
sections 80 and 78, and distributes the cables approximately along
a plane B that is extends within the section 76 toward the next
joint as shown in FIGS. 12, 13 and 19. Cable collectors similar to
cable collector 84 are used in several other places in the robots
12 and 16, wherever it is convenient to receive a centrally bundled
set of cables at one end and produce a planar distribution of the
cables at the other end, or vice versa. The cable collector 84 may
be used to distribute six cables instead of the four shown by
feeding the two additional cables through the upper pulleys 86
shown in FIG. 16 (similar to cable pairs 64a, 64b and 64c, 64d).
The fifth and sixth cables would then pass around the upper pulleys
88 shown in FIG. 17 (similar to cables 64c, 64d), and finally
around the outside of the pulleys 90 (again, similar to the cables
64c and 64d). Applicants have discovered that although the two
additional cables will be positioned directly above the two other
cables (64c and 64d), the two upper cables will fan out away from
the cables 64a-64d to form the planar distribution, in part,
because the receiving pulleys at the elbow joint 34 urge the cables
to form a planar distribution.
[0044] The cables 74a and 74b that control the axial rotation joint
32 extend above the cable connector 84 within the section 84, and
approach the plane B, as shown in FIGS. 19 and 20. The cables 64
and 74 are received between two sets of pulleys 78 and 80, each set
including six mutually independently rotatable pulleys as shown in
FIG. 22. The pulleys 78 and 80 ensure that the cables 64 and 74
remain approximately in the center of the joint 34 as the section
80 is rotated about the section 78 of the robot 12. This permits
the section 76 to be rotated with respect to the section 82 about
the joint 34 without significant attendant movement of the cables
64 and 74.
[0045] The joint 34 is actuated by either of cables 84a and 84b
which extend around pulleys 86a and 86b respectively in opposite
directions, and terminate at fixed points 88a and 88b respectively
on opposite sides of section 76 as shown in FIGS. 19 and 22. The
cables 64, 74, and 84 extend through the section 82 along a plane
generally indicated at C in FIG. 22.
[0046] As shown in FIG. 23, the cables 64, and 74 are received
between another two sets of pulleys 90 and 92 at the proximal end
of section 82 within joint 36. Each set of pulleys 90 and 92 also
includes six independently rotatable pulleys, and the pulleys 90
and 92 are positioned to permit the cables 64 and 74 to extend
through approximately the center to the joint 36. The section 82
may therefore be rotated with respect to the base section 94 about
joint 36 without significant attendant movement of the cables 64
and 74. The cables 84a and 84b extend through the joint 36 around
pulleys 96a and 96b respectively, and then around pulleys 98a and
98b respectively as shown in FIGS. 23 and 24. The cable 84a then
wraps around one more pulley 100a, and then both cables 84a and 84b
are brought to a hollow termination cylinder 102. In a preferred
embodiment, the ends of the two cables 84 wrapped around the
cylinder 102 are attached to each other, forming a single cable 84.
As the cylinder 102 is rotated between alternate directions, the
joint 34 is actuated in mutually opposing directions.
[0047] The shoulder section 94 may be rotated with respect to the
base 106 providing a joint 38 that has an axis of rotation that is
perpendicular to the axis of rotation of the joint 36 (as shown in
FIG. 2). The cables 64 and 74 extend through a cable collector 104
similar to the cable collector described above with reference to
FIGS. 15-18, except that six cables are run through the cable
collector 104. The cables extend from the collector 104 toward the
base 106 in three pairs that are positioned such that cables 74a
and 74b are visible in FIG. 23, and cables 74b, 64b, and 64d are
visible in FIG. 24.
[0048] Rotation about joint 34 may be effected by controlling the
movement of the motor M1, which causes cylinders 108, 110 and 102
to rotate, thereby effecting movement of cables 84 causing rotation
of the section 76 with respect to section 82 with respect to the
joint 34.
[0049] Rotation may be effected about joint 36 by controlling the
movement of the motor M2, which causes cylinders 112 and 114 to
rotate. Cylinder 114 is fixed to the section 82, so rotation of the
cylinder 114 causes rotation of the section 82 with respect to the
shoulder section 94 about joint 36.
[0050] Rotation about joint 38 may be achieved by controlling the
movement of the motor M3, which causes cylinders 116, 118, and 120
to rotate, thereby effecting movement of the shoulder section 94
with respect to the base 106 about joint 38.
[0051] The remaining six joints are controlled by the remaining six
motors in the base. Only two of the remaining motors M4 and M5 are
shown in FIG. 23. The other four motors are positioned in the base
behind the drive system for motors M4 and M5, as indicated in FIG.
25, and operate similar to the systems of motors M4 and M5. In
particular, cable 64c may be drawn toward the base by controlling
the movement of the motor M4, which causes cylinders 122 and 124 to
rotate. Similarly, cable 64d may be drawn toward the base by
controlling the movement of the motor M5, which causes cylinders
126 and 128 to rotate. With reference to FIGS. 23 and 25, it can be
seen that the other cables 64a, 64b, 74a and 74b may be similarly
controlled by four other motors and associated cylinders, including
cylinders 130, 132, 134 and 136 as shown.
[0052] The gearing ratios of the base rotation joint 38 (associated
with M3), the shoulder joint 36 (associated with M2) and the elbow
joint 34 (associated with M1) should each be about 40 to 1, while
the gearing ratios of the remaining joints should be about 8 to
1.
[0053] The slave robot 16 is identical to the master robot from the
base up to the joint 46, with the one exception that the gearing
ratio for the remaining joints (that was 8 to 1 with the master) is
20 to 1 for the slave robot 16. Specifically, the joint 40 on the
slave robot 16 is similar to the joint 38 on the master robot 12,
and the joint 42 on the slave robot is similar to the joint 36 on
the master robot, and the joint 44 on the slave robot is similar to
the joint 34 on the master robot. The slave robot also includes
cable tracking through the base 60 and shoulder section and section
140 similar to the cable tracking of the master robot 12 through
the base 58, shoulder section 94 and section 82.
[0054] In the slave robot 16, the joints 46 and 48 are not
controlled by any motors. The joint 46 is similar to the joint 32
described above with reference to FIGS. 12 through 18 except that
there are no cables that extend radially outwardly from the section
142 similar to the cables 74 that extend out from the section 76 on
the master robot 12. There are six cables that extend through the
section 142. The cables are collected by a cable collector (as
discussed above) prior to the joint 46 where they are redistributed
from a planar arrangement to a centrally positioned collection. The
six cables then pass through the joint 46 centrally positioned
similar to that shown in FIG. 14. Following the joint 46, the
cables are again redistributed by another cable collector from the
central position to a planar distribution.
[0055] The six planar distributed cables are then fed between two
sets of pulleys at the joint 48 as described above with reference
to FIGS. 19-22, except that all of the cables pass through the
joint. There are no pulleys at joint 48 similar to the pulleys 86
at joint 34. Joints 46 and 48 are passive joints.
[0056] The six cables then continue through the subsequent section
144. The joint 50 is identical to (though smaller in scale than)
the joint 32, and is driven by two cables in the same fashion that
cables 74a and 74b drive joint 32 as discussed above with reference
to FIGS. 12-18. A cable collector is also positioned on the
proximate side of the joint 50 to redistribute the remaining four
cables into the center of the section 146. The section 146
(together with the remaining four cables) pass into a patient 22
through the trocar sleeve 20.
[0057] As shown in FIGS. 26-33, the gripper portion 18 is similar
to (though smaller in scale than) the handle portion 24, except
that where the handle portion included a single pulley wheel
(pulley 68 in FIGS. 5 and 8), the associated arrangement of the
gripper portion includes two pulley wheels (see pulleys 150 of
FIGS. 27 and 31). Generally, cables 156a-156d extend through the
gripper portion around pulleys 158 (FIG. 29), around pulleys 160
(FIG. 30), around pulleys 150 (FIG. 31), around pulleys 162 (FIG.
32), and terminate on pulleys 164 (FIG. 33) as shown.
[0058] The cables 156 may be formed as discussed above in
connection with the handle portions shown in FIGS. 3-11, and the
guide pulleys 150, 158, and 162 may be independently freely
rotating or fixed. Again, PTFE spacers may be placed between
adjacent, independently rotating pulleys.
[0059] The gripper unit provides three degrees of freedom as
follows. When one of the cables, 156a, is moved relative the other
of its air, 156d, the associated gripper 166 will rotate with
respect to the central axis of the pulley 164. Similarly, when one
of the cables 156b is moved relative the other of its pair, 156c,
then the associated gripper 168 will rotate with respect to the
central axis of the pulley 164. When both of cables 156a and 156d
are pulled with respect to the other cables 156b and 156c (and vice
versa), then the gripper unit will rotate with respect to the
central axis of the pulleys 160. See FIGS. 27 and 30.
[0060] During operation, and with reference to the flow chart shown
in FIG. 34, a system including robotic manipulators of the
invention, begins (step 3400) by initializing variables and
establishing a home position for the master and robot slaves. The
system (step 3405) then reads the outputs of the optical encoders
to identify movement of the joints of the master robot. The system
also reads the outputs of the optical encoders of the slave robot
(step 3410) for identifying feedback. The feedback information is
utilized later in the process loop. The system then computes the
new position of the handle based on the position sensor signals
read from the optical encoders of the master robot (step 3415). A
new gripper position is then computed (step 3420) based on the new
handle position and a predetermined mapping function that maps
handle position to gripper position. The desired motor movements of
the slave robot (step 3425) are then computed based on the new
desired position of the gripper using inverse kinematics. The
desired gripper position is then compared (step 3430) with the
actual gripper position as known from monitoring the optical
encoder outputs of the slave robot motors. The voltages required to
move the gripper to the desired position are then calculated and
applied (step 3435) proportional to the difference between the
desired and actual positions of the gripper.
[0061] A feedback gripper position is then computed (step 3440)
based on the outputs of the optical encoders of the slave robot,
using forward kinematics. The associated handle position is then
computed (step 3445) based on the feedback gripper position using
the mapping function, and the desired motor movements are
calculated for the master robot using inverse kinematics (step
3450). The feedback voltages are applied to the required motors of
the master robot (step 3455) to effect the required feedback from
the slave robot. The process then returns to step 3405 and begins
again. The system may cycle very rapidly, providing continuous
actuation and feedback responses. The forward and inverse
kinematical equations are well known in the art, as is the
generation and use of three space mapping functions.
[0062] The process of FIG. 35 is similar to the process of FIG. 34
except that the feedback signals are responsive to torque sensors
instead of position sensors. Steps 3500-3535 are the same as steps
3400-3435 of FIG. 34. The system of FIG. 35 then reads the outputs
from torque force sensors on the slave robot (step 3540), which
outputs are then digitized (step 3545). A set of feedback gripper
forces are then calculated based on the torque sensor outputs using
forward kinematics (step 3550). Feedback handle forces are then
computed from the feedback gripper forces by using a mapping
function (step 3555), and the desired motor movements of the master
robot may then be calculated by inverse kinematics (step 3560). The
required voltages to be applied to the master robot motors may then
be calculated (step 3565), converted to analog signals (step 3570),
and then applied to the master robot motors (step 3575) to effect
the required feedback onto the master robot. The process then
returns to step 3505 and begins again.
[0063] As shown in FIGS. 36 and 37, in an alternative embodiment of
a system incorporating the benefits of the invention, a robot may
include a four bar linkage system. Specifically, the link 170 is
analogous to the link 82 of the system shown in FIG. 1, and the
joints 172 and 174 are analogous to the joints 34 and 36 of FIG. 1.
The cables controlling the link members at the distal end of the
robot may run through the joints 174 and 172 as well as the member
170 similar to the system of FIG. 1.
[0064] In the system of FIGS. 36 and 37, however, the link 176
(which is analogous to the link 76 of FIG. 1), extends beyond the
joint 172. The extended portion of member 176 is connected to
another joint 178, which in turn connects to member 180. Member 180
is connected at joint 182 to member 184 which extends to joint 174.
Members 176 and 184 are always parallel to each another, as are
members 170 and 180 always parallel to each other. The joint 172 is
actuated in the present embodiment, by having a cable extend from
the base 186 around a pulley at the joint 174 and fasten to member
184. When this cable is pulled, the member 184 rotates with respect
to the joint 174, rotating the member 176 with respect to the joint
172. The four bar linkage system, therefore, replaces the elbow
joint 34 actuator system of FIG. 1. The system of FIGS. 36 and 37
permits the elbow joint to be actuated from closer to the base, and
may provide for greater strength and rigidity.
[0065] As shown in FIG. 38, an alternative embodiment of a gripper
unit 200 of the invention includes link members instead of the
cables and pulleys of FIGS. 26-33. Specifically, one half of the
gripper unit 200 includes links 202-220 for controlling gripper
222, and the other half of the gripper unit includes links 232-248
for controlling gripper 252. The gripper unit halves are shown in
somewhat exploded view. The grippers 222 and 252 should be adjacent
one another during operation such that they may each rotate about
their respective openings 224 and 226 that are mounted along a
common axis 259 that is shown in exploded view in FIG. 38. The face
of gripper 222 that does not include the links 210 and 220, is
adjacent the face of gripper 252 that does not include the links
240 and 250.
[0066] Each of link members 206, 216, 236 and 246 include openings
228, 230, 254 and 256 respectively, that mutually align along an
axis generally indicated at 258. In various embodiments, the links
206, 216, 236 and 246 may be stacked in different orders along the
axis 258. For example, the links may be ordered from top down as
206, 216, 236 and 246, or they may be interleaved as 206, 236, 216
and 246.
[0067] As shown in FIG. 39, in a side view of one half of the
gripper unit 200 of FIG. 38, it can be seen that adjacent links
rotate about joint axes that are parallel with the axis 258. As
shown in FIG. 40, the gripper 222 rotates about the axis 259
through opening 224 that is orthogonal to the axis 258. The links
206, 216, 236 and 246 may rotate about the axis 258, but are
otherwise fixed in place. The grippers 222 and 252 may rotate about
the axis 259, and the secured a fixed distance from the axis 258,
but the pair of grippers 222 and 252 are together rotatable with
respect to the axis 258.
[0068] During use, when link 202 is pulled away from the axis 258
with respect to link 212, then link 210 will rotate (clockwise in
FIG. 39) until it contacts a stop 260 on the gripper 222. When the
stop 260 is contacted and link 202 continues to be pulled away from
the axis 258, then gripper 222 will begin to rotate (clockwise in
FIG. 39) about its opening 224. Pulling link 212 away from the axis
258 may similarly cause the gripper 222 to rotate (counterclockwise
in FIG. 39) about the opening 224 when link 220 contacts stop 262
on the gripper 222. The second portion of the gripper unit
including gripper 252 may be caused to rotate in a similar fashion
by pulling links 232 or 242 away from the axis 258.
[0069] If link members 202 and 212 are both pulled away from the
axis 258, then the entire gripper assembly (including grippers 222
and 252) will rotate (counterclockwise in FIG. 40) about the axis
258. Similarly, if links 232 and 242 are both pulled away from the
axis 258, then the entire gripper assembly will rotate (clockwise
in FIG. 40) about the axis 258.
[0070] The gripper assembly 200 may provide greater strength, and
reduced size. Moreover, the gripper assembly 200 may also provide
improved access through extremely small openings. If the links 210
and 220 are rotated about the axis 259 such that the outer ends of
the links 210 and 220 are drawn toward the axis 258 and close to
one another, and the links 240 and 250 of the gripper 252 are
similarly collapsed upon one another, then the gripper assembly 200
may be introduced through an opening that is only the size of the
round portion of the grippers 220 and 252. Once introduced through
the small opening, the links 210, 220, 240 and 250 may be rotated
outward to their respective stops (e.g., 260 on gripper 222),
whereupon the gripper assembly 200 may be employed within a
patient.
[0071] Any of the various features of the invention disclosed
herein may be employed in a wide variety of systems. Those skilled
in the art will appreciate that modifications and variations may be
made to the above disclosed embodiments without departing from the
spirit and scope of the invention.
* * * * *