Abstract
An articulating robotic arm for minimally invasive surgery, comprising a proximal arm segment extending along a longitudinal axis of the robotic arm and a distal arm segment connected to the proximal arm segment, pivotable about a pivot axis orthogonal to the longitudinal axis. The distal arm segment comprises a pinion segment formed with pinion teeth arranged about the pivot axis in the form of a pinion. A rack element is arranged on the proximal arm segment such that the rack element is movable in the longitudinal direction of the rack element parallel to the longitudinal axis by means of a translation, and rack teeth formed on the rack element are engaged with the pinion teeth so that a movement of the rack element in the longitudinal direction via the rack teeth and the pinion teeth is converted into a rotational movement of the distal arm segment about the pivot axis, and so that the distal arm segment pivots relative to the proximal arm segment about the pivot axis.
Claims
1. An articulating robotic arm for minimally invasive surgery, with a proximal arm segment extending along a longitudinal axis of the robot arm and a distal arm segment connected to the proximal arm segment, pivotable about a pivot axis which is orthogonal to the longitudinal axis, wherein the distal arm segment comprises a pinion segment formed with pinion teeth arranged about the pivot axis in the form of a pinion; and a rack element is arranged on the proximal arm segment in such a manner that the rack element is movable in the longitudinal direction of the rack element parallel to the longitudinal axis by means of a translation, and rack teeth formed on the rack element are engaged with the pinion teeth so that a movement of the rack element in the longitudinal direction via the rack teeth and the pinion teeth is converted into a rotational movement of the distal arm segment about the pivot axis and so that the distal arm segment pivots relative to the proximal arm segment about the pivot axis.
2. The articulating robotic arm according to claim 1, wherein the pinion teeth are formed as protrusions of the distal arm segment.
3. The articulating robotic arm according to claim 1, wherein the distal arm segment has a second pinion segment with pinion teeth arranged around the pivot axis, which second pinion segment is arranged spaced apart along the pivot axis from the pinion segment on the distal arm segment.
4. The articulating robotic arm according to claim 3, wherein the rack element has two sets of rack teeth, wherein the two sets of rack teeth are arranged parallel to and spaced apart from each other in the direction of the pivot axis such that the first set of rack teeth engages with the pinion teeth of the pinion segment and the second set of rack teeth engages with the pinion teeth of the second pinion segment.
5. The articulating robotic arm according to claim 1, wherein the rack element is formed with a proximal rack segment and a distal rack segment connecting to the proximal rack segment in the longitudinal direction, wherein the distal rack segment is wider in the direction of the pivot axis than the proximal rack segment.
6. The articulating robotic arm according to claim 1, wherein the proximal arm segment has a guide channel extending along the longitudinal axis in which the rack element, in particular with a proximal rack segment, is arranged and guided at least in sections.
7. The articulating robotic arm according to claim 1, wherein the proximal arm segment has an arm segment guide element, and the rack element has a rack element guide channel, wherein the arm segment guide element is arranged and guided at least in sections in the rack element guide channel.
8. The articulating robotic arm according to claim 1, wherein the distal arm segment is formed at least in sections as a flexible arm segment which can be angularly deflected continuously or quasi-continuously along its longitudinal extent.
9. The articulating robotic arm according to 8, wherein the flexible arm segment is formed with at least three pull-push elements which are arranged parallel along a longitudinal extent of the flexible arm segment and movable with respect to each other along the longitudinal extent.
10. The articulating robotic arm according to claim 1, wherein the distal arm segment is formed at least in sections as a discrete-robotic arm segment with segments arranged one behind the other along its longitudinal extent, wherein the discrete-robotic arm segment can be angularly deflected in segments along its longitudinal extent.
11. The articulating robotic arm according to claim 1, comprising a linear actuator connected to the rack element and configured to translationally move the rack element back and forth parallel to the longitudinal axis.
12. A surgical robot, in particular for minimally invasive surgery, with an articulating robotic arm according to claim 1.
13. The surgical robot according to claim 12, wherein the surgical robot is designed as a robot for assembly inside the body of a patient.
14. A method for producing an articulating robotic arm, comprising the steps of: providing a proximal arm segment whose direction of extent defines a longitudinal axis of the robotic arm; providing a distal arm segment comprising a pinion segment formed with pinion teeth arranged about a pivot axis in the form of a pinion; connecting the distal arm segment to the proximal arm segment such that the distal arm segment is pivotable about the pivot axis relative to the proximal arm segment and the pivot axis extends orthogonal to the longitudinal axis; and arranging a rack element on the proximal arm segment such that the rack element is movable in the longitudinal direction of the rack element parallel to the longitudinal axis by means of a translation, and rack teeth formed on the rack element are engaged with the pinion teeth so that a movement of the rack element in the longitudinal direction via the rack teeth and the pinion teeth is converted into a rotational movement of the distal arm segment about the pivot axis and the distal arm segment pivots relative to the proximal arm segment about the pivot axis.
Description
DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0042] In the following, further exemplary embodiments are explained in more detail with reference to figures of a drawing. In the figures:
[0043] FIG. 1 shows a schematic illustration of an articulating robotic arm for minimally invasive surgery;
[0044] FIG. 2A shows a schematic detail view of the articulating robotic arm according to FIG. 1;
[0045] FIG. 2B shows another schematic detail view of the articulating robotic arm according to FIG. 1;
[0046] FIG. 2C shows yet another schematic detail view of the articulating robotic arm according to FIG. 1;
[0047] FIG. 3 shows a schematic illustration of a rack element of an articulating robotic arm;
[0048] FIG. 4A shows a schematic illustration of a proximal arm segment of an articulating robotic arm;
[0049] FIG. 4B shows a schematic detail view of the proximal arm segment of FIG. 4A;
[0050] FIG. 5A shows a schematic illustration of an element of a distal arm segment of an articulating robotic arm;
[0051] FIG. 5B shows a schematic illustration of the element of FIG. 5A from a different perspective;
[0052] FIG. 5C shows a schematic sectional view of the element of FIG. 5A;
[0053] FIG. 6A shows a schematic illustration of a part of a surgical robot;
[0054] FIG. 6B shows a schematic detail view of the surgical robot of FIG. 6A;
[0055] FIG. 6C shows another schematic detail view of the surgical robot of FIG. 6A;
[0056] FIG. 7 shows a schematic illustration of a housing of a surgical robot;
[0057] FIG. 8 shows a schematic illustration of a fixing element for a surgical robot;
[0058] FIGS. 9A to 9G show schematic illustrations of the assembly procedure of a surgical robot for assembly in the body of a patient;
[0059] FIG. 10A shows a schematic view of an articulating robotic arm with a large angular deflection of a distal arm segment and a large bend of a flexible arm segment of the distal arm segment; and
[0060] FIG. 10B shows a schematic view of the angular robotic arm of FIG. 10A with a small angular deflection of the distal arm segment and a small bend of the flexible arm segment of the distal arm segment.
[0061] FIG. 1 shows an embodiment of an articulating robotic arm for minimally invasive surgery. The robotic arm is formed with a proximal arm segment 1 and a distal arm segment 2. Here, the proximal arm segment 1 is formed as a rigid segment. The distal arm segment 2 is formed with a fixed segment 3 and a flexible arm segment 4 connected distally thereto. The flexible arm segment 4 has five NiTi wires serving as pull-push means or elements 5. Two pairs of push-pull elements 5 each of which act antagonistically, are arranged around a central axis of the flexible arm segment 4. Pulling on one of the pull-push means 5 of a pair while simultaneously pushing on the other pull-push elements 5 of the pair causes an angular deflection in the form of a bend of the flexible arm segment 4. By means of pushing and pulling on a pull-push means 5 running on the central axis of the flexible arm segment 4, an end effector 6 of the robotic arm is actuated, which in the exemplary embodiment of FIG. 1 is a forceps element whose forceps jaws are opened and closed to provide a gripping movement.
[0062] As can be seen in the detail view of FIG. 2A, the proximal arm segment 1 and the distal arm segment 2 are connected to each other in an angularly deflectable manner. For this purpose, two flanks of the fixed segment 3 are arranged around a connection protrusion 7 and are pivotably connected to the connection protrusion 7 by means of a screw connection 8 passing through the flanks and the connection protrusion 7. The screw connection 8 thus defines a pivot axis of the distal arm segment 2 with respect to the proximal arm segment 1. For angularly deflecting the distal arm segment 2 with respect to the proximal arm segment 1, the distal arm segment 2 has two pinion segments 9 formed from the flanks, which are formed with pinion teeth 10, wherein the pinion teeth 10 are arranged around the pivot axis corresponding to a pinion. Rack teeth 11 of a rack element 12 engage with the pinion teeth. As a result of this, an angular deflection of the distal arm segment 2, namely the fixed segment 3, relative to the proximal arm segment 1 about the pivot axis can be achieved by means of a linear movement of the rack element 12, wherein the linear or translational movement of the rack teeth 11, via the engagement with the pinion teeth 10, cause a rotation of the pinion segments 9 and thus of the fixed segment 3 about the pivot axis. This angular deflection of the distal arm segment 2 is in principle independent of any angular deflection caused by a bending of the flexible arm segment 4, wherein, however, a relative change in the path of the pull-push means 5 when the fixed segment 3 is angularly deflected can result in an influence on the flexible arm segment 4.
[0063] The detail views of FIGS. 2B and 2C illustrate the angular deflection of the distal arm segment 2 with respect to the proximal arm segment 1 and the linear guidance of the rack element 12 during the angular deflection. In this connection, FIG. 2B illustrates a view of the proximal end of the proximal arm segment 1. FIG. 2C illustrates a view of the distal end of the proximal arm segment 1 with the distal arm segment 2 pivotably disposed thereon. It can be seen here that the pull-push elements 5 of the flexible arm segment 4 are guided along the entire length of the proximal arm segment 1 up to the proximal end thereof. Here, linear actuators can be operatively connected to the pull-push elements 5 to move them linearly and thus to actuate the flexible arm segment 4.
[0064] As shown in FIG. 3, the rack element 12 is formed with a narrow proximal rack segment 13 and a wider distal rack segment 14. Here, two sets of rack teeth 11 are formed on opposite sides of the distal rack segment 14, each of which engages pinion teeth 10 of one of the pinion segments 9 of the distal arm segment 2 in the articulating robotic arm.
[0065] FIG. 4A shows the proximal arm segment 1. FIG. 4B is a detail view of the distal end of the proximal arm segment 1. A guide channel 15, which receives the narrow proximal rack segment 13 for linearly guiding the rack element 12 in the longitudinal direction of the proximal arm segment 1, is formed in the proximal arm segment 1. The guide channel 15 is formed with a cross-section approximating a U-shape and the cross-section of the proximal rack segment 13 is adapted to the cross-section of the guide channel 15, as can be seen in FIG. 2B, for example.
[0066] Additionally, the proximal arm segment 1 has a guide rod 16 which is linearly guided in a rack element guide channel 17, thereby providing additional guidance of the translational movement of the rack element 12 for the angular deflection of the distal arm segment 2. The guide rod 16 is arranged at the distal end of the proximal arm segment 1 and protrudes therefrom in the longitudinal direction. The rack element guide channel 17 is formed on the underside of the wide distal rack segment 14, and the cross-sectional shapes of the guide rod 16 and the rack element guide channel 17 are matched with one another such that the rack element 12 with the rack element guide channel 17 can run on the guide rod 16 in the sense of a linear guide, as shown in FIGS. 2A and 2C, for example. In the exemplary embodiment shown, the rack element 12 and the rack element guide channel 17 have rectangular cross-sections. Alternatively, other cross-sectional shapes are also suitable, such as a U-shape or a V-shape.
[0067] FIGS. 5A and 5B show a fixed segment 3 of a distal arm segment 2 from different perspectives. On a side of the fixed segment opposite in the longitudinal direction to the pinion segments 9 formed on the flanks, guide holes 18 are formed which receive and linearly guide the pull-push elements 5 of the flexible arm segment 4. The pull-push elements 5 are guided through the guide holes from the flexible arm segment 4 to the proximal arm segment 1, and through the latter to the proximal end thereof, as can be seen in FIGS. 2A, 2B and 2C. At the proximal end of the proximal arm segment 1, the pull-push elements 5 can then be connected to linear actuators to drive and control the flexible arm segment 4.
[0068] FIG. 5C shows a sectional view of the fixed segment 3, in which it can be seen that the guide holes 18 are through-holes. Here, two guide holes 18a of the embodiment shown run partially through the flanks with the pinion segments 9 and open into a recess in the flanks, respectively. In FIG. 5C, it can be seen that the respective push-pull elements 5 can be guided in these guide holes 18a through a distal wall of the fixed segment 3 and then guided away from the respective flank by a slight bend.
[0069] When the fixed segment 3 is angularly deflected with respect to the proximal arm segment 1, a path from the proximal end of the proximal arm segment 1 to the distal end of the fixed segment 3 can change slightly for some of the pull-push elements 5, depending on their guidance along the robotic arm, which in turn can lead to a slight actuation of the flexible arm segment 4. Such a slight actuation of the flexible arm segment 4 can either be taken into account and used in an overall movement of the robotic arm, or it can be provided to compensate for the path change by a corresponding actuated countermovement of the respective pull-push element, thus avoiding an unwanted actuation of the flexible arm segment 4.
[0070] FIG. 6A shows a surgical robot with four articulating robotic arms according to the disclosure. Here, the four proximal arm segments 1a, 1b, 1c, 1d of the robotic arms are arranged over the major part of their respective longitudinal extent in an enveloping housing 19. The distal arm segments 2a, 2b, 2c, 2d with the fixed segments 3a, 3b, 3c, 3d and the flexible arm segments 4a, 4b, 4c, 4d are arranged outside the housing 19 and can move during an operation with the surgical robot.
[0071] In FIG. 6B, an angular deflection of the respective fixed segments 3a, 3b, 3c, 3d with respect to the respective proximal arm segments 1a, 1b, 1c, 1d is shown in detail. By means of an angular deflection of the respective fixed segments 3a, 3b, 3c, 3d, the flexible arm segments 2a, 2b, 2c, 2d can first be moved apart and subsequently, by bending the flexible arm segments 2a, 2b, 2c, 2d of their end effectors, can be brought back to each other at the surgical site from different directions, whereby surgical movements in the course of so-called triangulation can be facilitated compared to parallel guidance of the robotic arms to the surgical site.
[0072] FIG. 6C shows the surgical robot from a perspective from a proximal end. The proximal end of the surgical robot can be connected to other components for actuation of the robotic arms, in particular to a drive unit with actuators for driving the various degrees of freedom of the robotic arms.
[0073] In the embodiment shown, the surgical robot is a robot that can be assembled or mounted in the body of a patient. In this case, the articulating robotic arms are inserted individually into the patient's body and only thereafter are connected to one another in the housing 19 to form the surgical robot.
[0074] FIG. 7 is a detail view of the housing 19 of the surgical robot. It can be seen here that the housing 19 has recesses 20 at a distal end, which serve to mount the surgical robot, as explained in detail below.
[0075] FIG. 8 shows a sealing fixing element 21 which, after arranging a plurality of robotic arms in the housing 19, is inserted into a proximal end of the housing 19 to correctly position the robotic arms in relation to each other in the housing and to fix them in this position. At the same time, the fixing element 21 acts in a sealing manner. In particular, this can prevent insufflation gas from escaping from the patient's abdominal cavity between the robotic arms through the housing 19 during use, i.e., during an operation. For example, the fixing element 21 can be provided with a rubber coating for sealing purposes.
[0076] FIGS. 9A to 9G illustrate a mounting or assembly process of the surgical robot. Here, the robotic arms are inserted one after the other into the distal end of the housing 19. As can be seen in FIGS. 9A and 9B, the first robotic arm is inserted centrally into the housing 19 and then moved to the edge of the housing 19. In this manner, the other robotic arms can also be inserted into the housing 19 and moved to the edge of the housing 18. Insertion of the fourth robotic arm requires a twist to insert it through the cavity between the three robotic arms al-ready inserted and to subsequently move it to the edge of the housing 19 This can be seen in detail in FIGS. 9C and 9D.
[0077] Thereafter, a rearrangement of the robotic arms in the housing 19 takes place, as shown in FIGS. 9E and 9F, so that each of the robotic arms is arranged in an assigned mounted position. When arranging the robotic arms at the edge of the housing 19, as can be seen in FIGS. 9A to 9D, the respective connecting protrusion 7 of the respective robotic arm is pushed over the edge of the housing 19, thereby connecting the robotic arm to the edge of the housing. After rearrangement of the robotic arms, the respective connecting protrusions 7 are slid into the assigned recesses 20, thereby fixing the robotic arms in their mounted position at the distal end of the housing 19.
[0078] In alternative configurations, the robotic arms can be miniaturized such that they can be inserted directly into the housing 19 in their final arrangement. In this case, the step of rearranging during mounting can be omitted.
[0079] Finally, the sealing fixing element 21 is arranged in the proximal end of the housing 19 as shown in FIG. 9G, wherein FIG. 9G is a view of the distal end of the housing 19 so that the fixing element 21 is shown partially covered. The fixation element both fixes the robotic arms in their mounted arrangement to the proximal end of the housing 19 and maintains insufflation during an operation by means of the seal.
[0080] In alternative configurations, a surgical robot can be provided that is not mountable within a patient's body. For example, robotic arms can be arranged on arms of robots known as such, which remain completely outside the patient also during surgery and provide additional degrees of freedom.
[0081] In FIGS. 10A and 10B, an embodiment of an articulating robotic arm for minimally invasive surgery is shown in different states of movement. According to FIG. 10A, the fixed segment 3 is angled at an approximately right angle with respect to the proximal arm segment 1. It can be seen here that the rack element 12 is pushed far forward. In addition, the flexible arm segment 4 is strongly bent. The distal end of the robotic arm holds a weight. Compared to the state shown in FIG. 10A, the fixed segment 3 according to FIG. 10B is angled by a much smaller angle with respect to the proximal segment, and the flexible arm segment 4 is less strongly bent.
[0082] Load capacity tests were carried out with an exemplary embodiment of an articulating robotic arm. In this case, the structure of the robotic arm and the forms of movement corresponded to the illustrations in FIGS. 10A and 10B, with the proximal arm segment 1, the fixed segment 3 and the rack element 12 being produced by means of 3D printing. The robotic arm consists of proximal arm segment, distal arm segment with fixed segment, a screw connection, a rack, and a flexible arm segment. A pinion is integrated into the distal arm segment. The teeth of the rack and the teeth of the pinion engage with each other. The rack is guided by means of a guide channel. The flexible arm segment consists of discs. The discs have two functions: They ensure radial spacing between individual NiTi wires, and bending can be achieved by attaching all wires to the end of the flexible arm segment. An end disc is attached to both sides of each NiTi wire.
[0083] In the tests, the angle adjustment unit showed high functionality. The NiTi wires proved to be the weakest point. The meshing between the rack and pinion was flawless at all times. Although the angle adjustment mechanism was subjected to a double load due to the bending of the NiTi wires as well as the lifting of a load with a mass of 30 g and with the teeth being relatively flat with a height of approx. 1.5 mm, power was transmitted at all times. The minimal play between the pinion teeth and the rack teeth was sufficient to ensure smooth movement. Due to the guidance by guide rail, position-independent stability of the rack was achieved.
[0084] When the weight was attached directly to the end of the distal arm segment, i.e., to a base plate, loads of 200 g could be lifted without any problems. From this, it can be concluded that the angular deflection mechanism is suitable for use in minimally invasive surgery. Herein, it was unexpected that the combination of rack, pinion, and guide rail exhibited the established functionality as an angular adjustment mechanism, even with a high load of 200 g. The gearing proved to be reliable and positioning commands were implemented.
[0085] The features disclosed in the foregoing description, the claims, and the drawing can be relevant in the implementation of the various embodiments, either individually or in any combination.
