Tool changing system for robotic minimally invasive medical procedures

Abstract

The invention relates to a tool-changing system (50) for a robotic arm (13) of a medical robot. The tool-changing system comprises a fixed part (60) intended to be permanently positioned at one end of the robotic arm and a removable part (70) carrying a tool (80) adapted to assist a practitioner during a minimally invasive medical procedure. The removable part can be replaced to change the tool. The tool-changing system is configured such that, when the fixed part (60) and the removable part (70) are assembled together, a rotational movement of an actuating ring of the removable part relative to a locking pin of the fixed part allows a transition from an unlocked position to a locked position by pushing a locking element through the actuating ring into a recess in the locking pin. Figure for the abstract: Fig. 2

Description

Title of the invention: Tool changing system for robotic minimally invasive medical procedures Scope of the invention

[0001] This application falls within the field of robotic devices for assisting a practitioner during a medical procedure. More specifically, the application relates to a tool-changing system for a robotic arm of a medical robot. State of the art

[0002] In order to perform a minimally invasive medical intervention aimed at reaching a target anatomical area (for example to perform a biopsy or the removal of a tumor in an organ, to perform a vertebroplasty, a cementoplasty or to stimulate an anatomical area) in an anatomy of interest of a patient (for example a lung, a kidney, the liver, the brain, the tibia, the knee, a vertebra, etc.), an operator may be assisted by a medical robot comprising a robotic arm at the end of which is coupled a tool (for example a guide for a medical instrument such as a needle, an electrode, a probe, a trocar, etc.).

[0003] Advantageously, the tool can be coupled to the robotic arm via a tool changer, allowing the tool to be changed during or between procedures. Patent applications EP3939532A1, US20140066944A1, US20220409303A1, and CN114176737A provide various examples of the embodiment of a tool changer for a robotic arm of a medical robot.

[0004] It is important that the tool changer allows for quick and easy tool changes. Furthermore, the tool changer must ensure reliable tool mounting on the robotic arm. This means that the tool mounting must be identical and repeatable each time, and that it must not be possible to unintentionally dislodge the tool. Also, the tool changer must minimize errors introduced in calculating tool positioning during the medical procedure.

[0005] A sterile drape is generally used to isolate the robotic arm from the patient (the robotic arm is generally not sterilizable). The tool changer must then not compromise the sterility of the equipment used for the medical procedure. Furthermore, the positioning of the sterile drape must not cause any difficulty in mounting the tool onto the robotic arm.

[0006] Prior art tool changers do not optimally guarantee a quick, simple and reliable tool change with a sufficient level of sterility. Description of the invention

[0007] The present invention aims to remedy all or part of the drawbacks of the prior art, in particular those set out above.

[0008] To this end, and according to a first aspect, the present invention proposes a tool-changing system for a robotic arm of a medical robot. The tool-changing system comprises a fixed part intended to be permanently positioned at a distal end of the robotic arm and a removable part comprising a tool adapted to assist a practitioner during a minimally invasive medical procedure. The removable part can be replaced to change the tool. The fixed part comprises: - a chassis, - a locking pin of generally cylindrical shape, the surface of which includes at least one recess, - at least one positioning pin,

[0009] The removable part comprises: - a connecting piece comprising a tubular wall adapted to receive the locking pin, the tubular wall comprising at least one radial opening, the connecting piece comprising at least one orifice intended to cooperate with said at least one positioning pin, - an actuation ring comprising at least one slope on its internal surface, - at least one locking element housed at the level of said at least one radial opening between the internal surface of the actuating ring and the tubular wall of the connecting piece.

[0010] The tool changing system is configured so that, when the fixed part and the removable part are assembled together so that said at least one positioning pin is housed in said at least one orifice, a rotational movement of the actuating ring relative to the locking stud allows a passage from an unlocked position to a locked position by a push of the locking element by said at least slope of the actuating ring, along a radial axis, in said at least one recess of the locking stud.

[0011] The tool changing system according to the invention allows for quick and easy mounting of a tool on the robotic arm. The system is designed to allow the user to mount or remove a tool on the robotic arm by a simple rotation of the actuating ring.

[0012] In addition, the assembly is particularly reliable. Indeed, thanks to the irreversible geometry of the locking mechanism, the tool cannot be detached from the robotic arm unintentionally: only a rotational movement of the actuating ring around the locking pin allows the removable part to be detached.

[0013] In particular embodiments, the invention may further comprise one or more of the following features, taken individually or in all technically possible combinations.

[0014] In particular embodiments, the fixed part and the removable part each have at least one visual marker indicating the locked position or the unlocked position when the fixed part and the removable part are assembled together and said visual markers are opposite each other.

[0015] In particular embodiments, the tool and the actuation ring each comprise at least one optical marker.

[0016] In particular embodiments, the removable part includes at least one NFC tag, and the fixed part includes at least one NFC reader configured to receive information transmitted by said at least one NFC tag of the removable part when the fixed part and the removable part are assembled together and the actuating ring is in the locked position.

[0017] In particular embodiments, the tool includes a device for guiding a medical instrument such as a needle, a probe, an electrode, a catheter, a screw, a drill or a trocar.

[0018] In particular embodiments, the tubular wall of the connecting piece of the removable part has at least one additional radial opening to promote sterilization of the removable part.

[0019] In particular embodiments, the tool-changing system further comprises a sterile drape intended to cover at least the robotic arm of the medical robot. The sterile drape has a circular opening, the periphery of which is formed by a ring intended to grip a shoulder of the frame of the fixed part. The shoulder is configured to be covered by the actuating ring when the fixed part and the removable part are assembled together, the ring then being held between the shoulder and the actuating ring.

[0020] Advantageously, placing the sterile drape at the tool changing system does not add any additional interface that could cause difficulties in locking the system. This is because the sterile drape is positioned radially with respect to the main axis of the tool changing system. In this way, no interface is added at the contact plane between the fixed and removable parts. This last point ensures better repeatability of tool mounting on the robotic arm.

[0021] In particular embodiments, the sterile sheet includes an NFC tag, the fixed part includes an NFC reader configured to receive information transmitted by the NFC tag of the sterile sheet when the ring of the sterile sheet encircles the shoulder of the frame of the fixed part.

[0022] According to a second aspect, the present invention relates to a medical robot comprising a robotic arm and a tool changing system according to any one of the preceding embodiments.

[0023] In particular embodiments, the medical robot includes a control unit for the robotic arm, and the fixed part of the tool changing system includes a display screen connected to the control unit and taking the form of a flexible band wrapped around the chassis of the fixed part.

[0024] In particular embodiments, the control unit is configured to display on the display screen an indication relating to the control of the robotic arm.

[0025] In particular embodiments, the tool and the actuating ring of the removable part of the tool-changing system each comprise at least one optical marker, and the control unit is configured to: - receive information from an optical navigation system relating to the positions of the optical markers of the tool and the actuating ring, - check, based on the position information of the optical markers, whether the actuation ring is in the locked position.

[0026] In particular embodiments, the control unit is configured to check, depending on whether or not the information transmitted by the NFC tag of the sterile sheet is received, whether the sterile sheet is correctly positioned on the fixed part of the tool changing system.

[0027] In particular embodiments, the control unit is configured to check, based on the information transmitted by said at least one NFC tag of the removable part, whether the tool is suitable for a minimally invasive medical intervention planned and memorized by the control unit.

[0028] In particular embodiments, predetermined calibration data for different removable parts are stored in the control unit or are accessible by the control unit. The information transmitted by the NFC tag of the removable part includes an identifier for the removable part. The control unit is configured to select, from this identifier, calibration data to be used to control the robotic arm.

[0029] Each removable part is measured and calibrated after the various parts have been assembled. Thanks to this calibration, the system is free from positioning errors related to the assembly of the removable part's components during its manufacture. Presentation of the figures

[0030] The invention will be better understood upon reading the following description, given by way of non-limiting example, and made with reference to Figures 1 to 13, which represent:

[0031] [Fig. 1] a schematic representation of an example of an embodiment of a medical robot,

[0032] [Fig.2] an example of an embodiment of a tool changing system for the arm robotic medical robot shown in [Fig. 1],

[0033] [Fig.3] an example of an embodiment of the fixed part of the tool changing system represented in [Fig.2],

[0034] [Fig.4] an example of an embodiment of the removable part of the changing system of tool shown in [Fig.2],

[0035] [Fig.5] another view of the example embodiment of the removable part shown in Figure 4, highlighting the parts encircled by the actuating ring,

[0036] [Fig. 6] a representation, according to a cross-sectional view, of the assembled removable part on the fixed part in an unlocked position,

[0037] [Fig.7] a representation, according to a cross-sectional view, of the assembled removable part on the fixed part in a locked position,

[0038] [Fig.8] a representation of the actuating ring in a position unlocked

[0039] [Fig.9] a representation of the actuating ring in a locked position,

[0040] [Fig. 10] an illustration of the placement of a sterile drape at the level of the fixed part of the tool change system for covering the robotic arm,

[0041] [Fig. 11] a schematic representation of the placement of the sterile drape at the level of the fixed part of the tool changing system,

[0042] [Fig. 12] a representation of the connecting piece of the removable part intended to receive the locking pin for the fixed part,

[0043] [Fig.13] another view of the connecting piece illustrated in [Fig.12].

[0044] In these figures, identical reference numerals from one figure to another designate identical or analogous elements. For clarity, the elements shown are not necessarily to the same scale, unless otherwise stated.

[0045] Detailed description of an embodiment of the invention

[0046] Fig. 1 schematically represents an example of an embodiment of a medical robot 10. The medical robot 10 is used to assist a practitioner during a minimally invasive medical intervention on an anatomy of interest of a patient 20 positioned on an operating table 21.

[0047] This type of intervention generally requires the insertion by the practitioner of one or more medical instruments 15 into the patient's body 20 from an entry point located at the level of the patient's skin to a certain depth to reach a target point in or near a region to be treated of the anatomy of interest.

[0048] The intervention may in particular aim to remove or biopsy a tumor in an organ or in a bone, to treat a bone pathology (for example (by vertebroplasty or cementoplasty), or to stimulate a particular anatomical area. The anatomy of interest may correspond to an organ or a bone, for example the liver, a lung, a kidney, the brain, a vertebra, the tibia, the femur, the hip, the knee, the pelvic bones, the pelvis, etc. The medical instrument 15 may be a needle, an electrode, a probe, a drill, a trocar, a screw, etc.

[0049] In the example considered and illustrated in [Fig.1], the medical robot 10 includes a base 11. The base 11 of the medical robot 10 is equipped with motorized wheels, which allows the medical robot 10 to move in different directions by translational and / or rotational movements.

[0050] The medical robot 10 further comprises a robotic arm 13, one end of which is connected to the base 11. A tool-changing system 50 is attached to the other end of the robotic arm 13. As will be detailed later, the tool-changing system 50 includes a removable part with a tool adapted to assist the practitioner during the minimally invasive procedure. This tool is, for example, intended to guide the medical instrument 15 (e.g., a needle, a probe, an electrode, or a trocar). The medical robot 10 thus acts as a third hand for the practitioner.

[0051] As illustrated in [Fig. 1], the medical robot 10 includes a control unit 12 configured to control the movement of the robotic arm 13 (and therefore of the tool carried by the robotic arm 13). The control unit 12 includes at least one processor 122 and at least one memory 121 (magnetic hard drive, electronic memory, optical disk, etc.) in which a computer program product is stored, in the form of a set of program code instructions to be executed to implement the control of the robotic arm 13.

[0052] In the example considered and illustrated in [Fig.1], the robotic arm 13 has six revolute joints 131 to 136 giving six degrees of freedom allowing the medical instrument 15 to be positioned and / or moved in any pose in three-dimensional space (in the present application, the term "pose" should be understood as meaning "position and orientation").

[0053] As illustrated in [Fig. 1], a navigation system 30 can be used to provide the control unit 12 of the medical robot 10 with information relating to a current pose of the tool 80 and an insertion pose that the tool 80 must reach. The current pose and the insertion pose are, for example, initially defined in a reference frame of the navigation system 30 and then transformed into poses in a reference frame of the medical robot 10 by the control unit 12. The control unit 12 can then be configured to automatically move the robotic arm 13 so that it reaches the insertion pose. The insertion pose corresponds to a pose of the tool 80 at which allows the medical instrument 15 to be guided along a planned trajectory and to the exact depth to reach the target point in the anatomy of interest.

[0054] The navigation system 30 and the control unit 12 of the medical robot 10 can exchange data via communication means (wired or wireless). In the example considered, the navigation system 30 is an optical navigation system. As illustrated in [Fig. 4], the tool 80 has pads 82 designed to hold optical markers. All the optical markers present on the tool 80 correspond to a robot reference 14. The use of at least three optical markers makes it possible to define a plane and therefore a direct orthonormal three-dimensional reference frame. This allows the pose of the reference frame formed from the optical markers that represent the tool 80 to be determined.

[0055] As illustrated in [Fig. 1], a patient reference 22 is placed on patient 20 near the anatomy of interest. In the example considered, the patient reference 22 also has at least three optical markers, so that the position of the patient reference 22 can be determined in the three spatial dimensions of the reference frame of the navigation system 30.

[0056] The insertion position that the tool 80 must reach can in particular be defined from the position of the patient reference 22. For this purpose, the patient reference 22 also includes radio-opaque markers that are visible on a medical image acquired by a medical imaging device (for example by computed tomography, magnetic resonance imaging, ultrasound, tomography, positron emission tomography, etc.).

[0057] It is thus possible to plan the medical intervention from a pre-intervention medical image 40 acquired on the patient with the patient reference 22. This pre-intervention medical image 40 is stored in the memory 121 of the control unit 12. It is then possible for the control unit 12, from the pre-intervention medical image 40, to define the insertion position that the tool 80 must take to guide the medical instrument 15 to perform the medical intervention.

[0058] The planning involves determining, on the pre-intervention image 40, the trajectory 41 to be followed by the medical instrument 15 (e.g., a needle) between an entry point 43 located on the skin of patient 20 and a target point 44 located in or near a region to be treated (e.g., a tumor) in the anatomy of interest 45 (e.g., the liver) of patient 20. The patient reference 22 (more precisely, the radiopaque elements of the patient reference 22) is visible on the pre-intervention image 40. The position of the patient reference 22 can therefore be defined in the medical image. The insertion position of the tool 80, which allows the trajectory 41 to be followed, can then be defined relative to the position of the patient reference 22.

[0059] Using the navigation system 30, the medical robot 10 can determine the placement of the tool 80 (or more precisely the placement of the robot reference 14) and the placement of the patient reference 22. Thanks to the pre-intervention image 40, the medical robot 10 knows the insertion position that the tool 80 must reach in relation to the position of the patient reference 22. The control unit 12 can then be configured to automatically move the robotic arm 13 so that it reaches the insertion position.

[0060] It is important to be able to change tools easily, quickly, and reliably during a medical procedure (for example, when several different medical instruments need to be inserted into the patient's body during the same procedure), or between two medical procedures. It is also important to guarantee a sufficient level of sterility of the equipment used during a medical procedure.

[0061] Figure 2 illustrates an example of an embodiment of a tool-changing system 50 for the robotic arm 13 of the medical robot 10 described above with reference to Figure 1. The tool-changing system 50 comprises a fixed part 60 intended to be permanently positioned at the distal end of the robotic arm 13, and a removable part 70 carrying a tool 80 adapted for the intended medical procedure. The removable part 70 can be replaced to change the tool.

[0062] Figure 3 shows an example of an embodiment of the fixed part 60 of the tool changing system 50. The fixed part 60 comprises a frame 61, preferably made of electrically insulating material, for example plastic, to allow electrical isolation with the tool 80 (or with the medical instrument 15 carried by the tool 80 if the tool is a guide).

[0063] The fixed part 60 also includes a locking pin 62, generally cylindrical in shape, the surface of which has at least one recess 63 (for example, a groove, a channel, a channel, or a hollow). The recess or recesses are arranged circumferentially on the cylindrical surface of the locking pin 62. In the example considered and illustrated in [Fig. 3], the recess 63 corresponds to a groove that occupies the entire circumference of the locking pin 62. However, according to another embodiment, nothing would prevent having several disjointed grooves along the circumference of the locking pin 62.

[0064] The fixed part 60 also includes at least one positioning pin 64. As will be seen later, this positioning pin 64 serves as a reference for correctly assembling the removable part 70 onto the fixed part 60. In the example considered and illustrated in [Fig.3], the fixed part 60 includes two positioning pins 64 on the chassis 61.

[0065] The chassis 61 serves as a support for the locking pin 62 and the positioning pin(s) 64.

[0066] Figures 4 and 5 represent an example of an embodiment of the removable part 70 of the tool changing system 50.

[0067] In the example considered, and as illustrated in [Fig. 4], the removable part 70 comprises a tool 80 which includes a guiding device 81 with two parts movable relative to each other. The guiding device 81 is designed to hold and guide the medical instrument 15 (for example, a needle, probe, electrode, catheter, screw, drill bit, or trocar) within a clamp formed by the two movable parts. The two movable parts of the guiding device 81 can be driven by a system such as a gear, cam, reverse-threaded screw, and / or linear actuator, in order to lock or release the medical instrument 15. The tool 80 allows, for example, the guidance of medical instruments of different diameters. For example, it allows the guidance of medical instruments with a diameter between 11 and 21 gauges.The guidance device 81 can in particular follow one of the embodiments described in patent application FR3094627A1.

[0068] As illustrated in [Fig. 5], the removable part 70 comprises a connecting piece 74 having a tubular wall 75 adapted to receive the locking pin 62 (in other words, the locking pin 62 is intended to fit into the space formed inside the tubular wall 75 of the connecting piece 74 when the removable part 70 is assembled onto the fixed part 60). The connecting piece 74 has at least one opening 77 for cooperating with a positioning pin 64 of the fixed part 60. In the example considered and illustrated in [Fig. 5], the connecting piece 74 has two openings 77 for receiving the two positioning pins 64 of the fixed part 60. The tubular wall 75 also has one or more radial openings 76 arranged circumferentially around the tubular wall 75 of the connecting piece 74.

[0069] As illustrated in [Fig. 5], the removable part 70 also includes an actuating ring 71 and at least one locking element 78 housed in a radial opening 76, between the inner surface of the actuating ring 71 and the tubular wall 75 of the connecting piece 74. In the example considered and illustrated in [Fig. 5], there are three radial openings 76 and three locking elements 78 (only two are visible in the figure). Each locking element 78 is in the form of a ball. Each radial opening 78 is in the form of a circular opening whose diameter is smaller than that of the ball it accommodates, in order to prevent the ball from passing through the opening.

[0070] The tool changing system 50 is configured such that, when the fixed part 60 and the removable part 70 are assembled with each other so that the positioning pins 64 are housed in their respective holes 77, a rotational movement of the actuating ring 71 relative to the stud of The locking mechanism 62 allows a transition from an unlocked position to a locked position by pushing each locking element 78 through a slope of the internal surface of the actuating ring 71, along a radial axis, into the recess 63 of the locking pin 62 (the internal surface 72 of the actuating ring 71 and the slope 73 of the internal surface 72 are visible in Figures 8 and 9 which will be described later).

[0071] The recess 63 is therefore shaped to accommodate the locking elements 78. In other words, the shape of the recess 63 allows the locking elements 78 to fit into the recess 63 when the fixed part 60 and the removable part 70 are assembled in the locked position. The fitting of each locking element 78 into the recess 63 keeps the tool-changing system 50 in the locked position.

[0072] As previously stated, nothing would prevent, in a variant, several distinct recesses 63 from being arranged circumferentially on the cylindrical surface of the locking stud 62 (instead of a single recess all along the circumference of the locking stud 62), so that each recess 63 is adapted to accommodate a locking element 78.

[0073] In the example considered and illustrated in the figures, a fraction of a turn (for example, one-sixth of a turn) of the actuating ring 71 in one direction allows the movement from the unlocked position to the locked position. A fraction of a turn of the actuating ring 71 in the opposite direction allows the movement from the locked position to the unlocked position.

[0074] Figures 6 to 9 illustrate the assembly of the removable part 70 with the fixed part 60, and the transition from the unlocked position to the locked position.

[0075] Figure 6 shows the assembly of the removable part 70 onto the fixed part 60 in the unlocked position. It can be seen in particular on [Fig.6] that the locking element 78 is not fitted into the recess 63 of the locking pin 62. In this position, the locking element 78 rests at the bottom of a slope 73 cut into the internal surface 72 of the actuating ring 71.

[0076] Figure 8 shows the actuating ring 71 and the locking elements 78 in the unlocked position. It can be seen in this figure that, in the unlocked position, each locking element 78 rests at the bottom of a slope 73 cut into the inner surface 72 of the actuating ring 71.

[0077] Figure 7 shows the assembly of the removable part 70 onto the fixed part 60 in a locked position. It can be seen in particular on [Fig.7] that the locking element 78 is fitted into the recess 63 of the locking pin 62. In this position, the locking element 78 rests at the top of the slope 73 cut into the internal surface 72 of the actuating ring 71.

[0078] Figure 9 shows the actuating ring 71 and the locking elements 78 in the locked position. It can be seen in this figure that, in the locked position, each locking element 78 rests at the top of a slope 73 cut into the inner surface 72 of the actuating ring 71.

[0079] During the transition from the unlocked position (Figures 6 and 8) to the locked position (Figures 7 and 9), the rotational movement of the actuating ring 71 relative to the locking pin 62 causes the locking elements 78 to be pushed by the slopes 73 of the internal surface 72 of the actuating ring 71, along a radial axis, towards the recess 63 of the locking pin 62, through the radial openings 76. The locking elements 78 then engage in the recess 63 and hold the tool-changing system 50 in the locked position. Only a reverse rotational movement of the actuating ring 71 can then allow the transition from the unlocked position to the locked position. During this reverse rotation movement, the locking elements 78 move away from the recess 63, reaching the bottom of the slopes 73, thus allowing a separation of the fixed part 60 and the removable part 70.

[0080] The inclination of the slopes 73 is preferably very shallow (less than a few degrees, for example, less than 5°) to ensure the irreversibility of the system. An irreversible mechanism is a system that can be actuated by only one component, called the driving element. In the case of the tool-changing system 50 according to the invention, the driving element is the actuating ring 71. Each ball (locking element 78) moves in contact with the slope 73 during a rotational movement of the actuating ring 71. These balls cannot, under any circumstances, open the mechanism by applying any force to the balls other than that caused by a rotational movement of the actuating ring 71. This phenomenon ensures that the tool-changing system 50 cannot open during operation without the activation of the actuating ring 71.

[0081] In particular embodiments, and as illustrated in [Fig.3], the fixed part 60 of the tool changing system 50 includes a display screen 66 connected to the control unit 12. The display screen 66 takes, for example, the form of a flexible band wrapped around the frame 61 of the fixed part 60. The control unit 12 can then be configured to display on the display screen 66 an indication relating to the control of the robotic arm 13 (for example, to indicate whether the robotic arm 13 is moving, whether the tool 80 has reached the insertion position, whether the tool 80 is approaching an obstacle or is in contact with an obstacle, and / or whether an urgent action must be taken by the practitioner). The 66-inch display screen allows the practitioner to receive feedback on the ongoing procedure without having to take their eyes off the operating field.

[0082] To detect whether the tool 80 is approaching an obstacle, the tool-changing system 50 may include a distance sensor, such as an ultrasonic sensor or a retroreflective photoelectric sensor. To detect whether the tool 80 is in contact with an obstacle, the tool-changing system 50 may include a force sensor 68 (see [Fig. 3]). When the tool 80 encounters an obstacle, the force sensor 68 detects a discontinuity in the perceived forces and moments.

[0083] As illustrated in [Fig. 2], the fixed part 60 and the removable part 70 may each have at least one visual marker 65a, 65b indicating the locked or unlocked position when the fixed part 60 and the removable part 70 are assembled together and said visual markers 65a, 65b are facing each other. For example, the assembly ring 71 of the removable part 70 has a visual marker 65b in the shape of an arrow, and the fixed part 60 has a first visual marker 65a in the shape of an open padlock and a second visual marker in the shape of a closed padlock.When the fixed part 60 and the removable part 70 are assembled together, with the positioning pins 64 housed in their respective holes 77, if the arrow points to the open padlock, this means that the tool changing system 50 is in the unlocked position (the removable part 70 can then be freely removed from the fixed part 60), and if the arrow points to the closed padlock, this means that the tool changing system 50 is in the locked position (the removable part 70 cannot then be removed from the fixed part 60 without rotating the actuating ring 71).

[0084] It may be advantageous to automatically detect whether the tool changing system 50 is in the locked position. For this purpose, the actuating ring 71 may include an optical reference formed by one or more optical markers similar to those of the tool 80. The navigation system 30 can then enable the control unit 12 of the medical robot 10 to determine the position of the actuating ring 71 relative to the position of the tool 80, and to deduce whether the tool changing system 50 is in the locked position or not. Advantageously, an indication of whether the tool changing system 50 is in the locked position or not can be displayed on the display screen 66.

[0085] In particular embodiments, the removable part 70 includes an NFC tag, and the fixed part 60 includes an NFC reader configured to receive information transmitted by the NFC tag of the removable part 70 when the fixed part 60 and the removable part 70 are assembled together and the actuating ring 71 is in the locked position. The term "NFC" is the English acronym for "Near Field Communication." "in the near field." This is a short-range (on the order of centimeters) and high-frequency wireless communication technology.

[0086] The control unit 12 can then be configured to check, based on the information transmitted by the NFC tag of the removable part 70, whether the tool changing system 50 is in the locked position or not. Indeed, for the NFC reader to receive information from the NFC tag, the reader and the tag must be facing each other (they must be sufficiently close to each other). The reader and the tag can be arranged so that when the NFC tag of the removable part 70 is facing the NFC reader of the fixed part 60, it means that the tool changing system 50 is in the locked position. Thus, when the NFC reader receives information from the NFC tag, it means that the removable part 70 is correctly assembled to the fixed part 60 in the locked position. This provides another way to automatically detect whether the tool changing system 50 is in the locked position.Here again, an indication of whether the tool changing system 50 is locked or not can be displayed on the display screen 66.

[0087] It is also possible to use two NFC readers at the level of the fixed part 60 and one NFC tag at the level of the removable part 70. The readers and the NFC tag can be arranged in such a way that when the NFC tag of the removable part 70 is opposite a first NFC reader of the fixed part 60 this means that the tool changing system 50 is in the unlocked position, and when the NFC tag of the removable part 70 is opposite a second NFC reader of the fixed part 60 this means that the tool changing system 50 is in the locked position.

[0088] It is also possible to use two NFC tags on the removable part 70 and an NFC reader on the fixed part 60. The tags and the NFC reader can be arranged so that when a first NFC tag on the removable part 70 is opposite the NFC reader on the fixed part 60 it means that the tool changing system 50 is in the unlocked position, and when a second NFC tag on the removable part 70 is opposite the NFC reader on the fixed part 60 it means that the tool changing system 50 is in the locked position.

[0089] The control unit 12 can also be configured to check, based on the information transmitted by the NFC tag of the removable part 70, whether the tool 80 is suitable for the minimally invasive medical intervention planned and stored by the control unit 12. The information transmitted by the NFC tag of the removable part 70 can indeed correspond to an identifier of the tool 80 carried by the removable part 70, and the control unit 12 can store data associating for each tool identifier one or more types of intervention likely to be implemented with the corresponding tool.

[0090] In particular embodiments, predetermined calibration data for different removable parts are stored in the control unit 12 (or are accessible by the control unit 12, for example via communication with a data server). If the information transmitted by the NFC tag of the removable part 70 includes an identifier of the removable part 70, the control unit 12 can be configured to select, from said identifier, calibration data to be used to control the robotic arm 13.

[0091] Advantageously, the various parts of the removable part 70 (in particular the actuating ring 71, the connecting piece 74, the locking elements 78, and the tool 80) are assembled by the manufacturer and cannot be disassembled by the user. This allows for calibration of the entire removable part 70 to ensure greater accuracy of the component as a whole. Calibration consists of metrological measurement, using a coordinate measuring machine (CMM), of the functional geometries of the component formed by the removable part 70. For example, calibration consists of measuring: - of the contact plane 85 between the fixed part 60 and the removable part 70 (see [Fig.11]), - of the orifice 77 housing for the positioning pin 64, - of the axis of the medical instrument 15 intended to be guided by the guidance device 81, - a mechanical stop allowing the medical instrument 15 to stop in translation during its insertion.

[0092] With knowledge of these unique calibration data for each component, the position of each part is transparent in the positioning of the assembly through the robotic arm 13. In other words, all interfaces between the different elements of the component do not generate positioning errors, because the component (i.e., the set of parts forming the component) is measured after assembly. The positioning error of the medical instrument 15 is then limited to: - the accuracy of the calibration measurement, - the error related to the repeatability of the mounting of the removable part 70 on the fixed part 60. - the error related to the repeatability of the positioning of the medical instrument in the guidance device 80.

[0093] Conversely, if the component (the removable part 70) was not calibrated as a whole, then the manufacturing accuracy of each of the parts should be taken into account in the overall positioning error of the medical instrument 15.

[0094] As previously stated, the tool-changing system 50 must not compromise the sterility of the equipment used for the medical procedure. It is It is advantageous to use a sterile sheet to cover the robotic arm 13 or even the entire medical robot 10. The removable part 70 is sterilized before each intervention.

[0095] To facilitate the assembly of the removable part 70 with the fixed part 60 despite the presence of the sterile drape, it is advantageous to use a sterile drape specially adapted to the tool-changing system 50. For this purpose, and as illustrated in [Fig. 10], the tool-changing system 50 may include a sterile drape 90 having a circular opening, the periphery of which is formed by a ring 91 intended to grip a shoulder 67 of the frame 61 of the fixed part 60. The ring 91 may be made of a rigid material so as to be press-fitted onto the shoulder 67. Alternatively, the ring 91 may be made of an elastic material to facilitate its positioning on the shoulder 67. Advantageously, the shoulder 67 is configured to be covered by the actuating ring 71 when the fixed part 60 and the removable part 70 are assembled together.The ring 91 is then held between the shoulder 67 and the actuating ring 71 (the ring 91 is sandwiched between the shoulder 67 and the actuating ring 71). The ring 91 may also include a positioning element (groove, pin, flat) intended to cooperate with the shoulder 67 to prevent the ring 91 from rotating around the shoulder 67 once the sterile drape is positioned.

[0096] With such arrangements, an operator does not have to touch a non-sterile part of the robotic arm 10 when assembling the removable part 70 or when removing the removable part 70 to install another in order to change tool 80.

[0097] Since the ring 91 is held between the shoulder 67 and the actuating ring 71, the risk of the sterile drape 90 moving from its attachment point during a movement of the robotic arm 13 is limited. In other words, once assembled, the sterile drape can no longer be moved or expose a non-sterile portion.

[0098] Furthermore, the circular opening in the sterile drape 90 prevents the sterile drape from obstructing the assembly of the fixed part 60 with the removable part 70. As can be seen in [Fig. 11], when the sterile drape 90 is positioned, no interface is added at the contact plane 85 between the fixed part 60 and the removable part 70 (in particular, the sterile drape 90 does not come into contact with this contact plane 85). This ensures better repeatability of the assembly of the removable part 70 onto the fixed part 60 of the tool-changing system 50.

[0099] In particular embodiments, the sterile sheet 90 has an NFC tag, and the fixed part 60 has an NFC reader configured to receive information transmitted by the NFC tag of the sterile sheet 90 when the ring 91 of the sterile sheet encircles the shoulder 67 of the frame 61 of the fixed part 60.

[0100] The control unit 12 can then be configured to check, depending on whether or not the information transmitted by the NFC tag of the sterile sheet 90 has been received, whether the sterile sheet 90 is correctly positioned on the fixed part 60 of the tool changing system 50.

[0101] Indeed, in order for the NFC reader to receive information from the NFC tag, the reader and the tag must be facing each other (they must be sufficiently close to each other). The reader and the tag can be arranged so that when the NFC tag of the sterile drape 90 is facing the NFC reader of the fixed part 60, this means that the sterile drape 90 is correctly positioned on the fixed part 60 of the tool changing system 50.

[0102] The NFC reader used to read information from the NFC tag on the sterile drape may be the same NFC reader used to read information from a tag on the removable part 70 of the tool-changing system 50. Alternatively, different NFC readers may be used.

[0103] Advantageously, the information transmitted by the NFC tag of the sterile sheet 90 can include an identifier (for example a serial number) of the sterile sheet 90. It then becomes possible to automate the traceability of the material (sterile sheet 90 and / or tool 80) used during the medical intervention and the management of stocks of the hospital in which the intervention takes place.

[0104] As illustrated in Figures 5, 12 and 13, to promote sterilization of the removable part 70, the tubular wall 75 of the connecting piece 74 of the removable part 70 may have one or more additional radial openings 79. These additional radial openings 79 are not associated with locking elements 78. The purpose of the additional radial openings 79 is to allow the passage of a sterilizing product (fluid) into the space separating the tubular wall 75 of the connecting piece 74 and the inner surface 72 of the actuating ring 71.

[0105] Furthermore, the base of the connecting piece 74 is designed with specific geometric shapes 86 to limit the interface surface between this base and the actuating ring 71 when the connecting piece 74 is attached to the actuating ring 71. This also promotes sterilization of the removable part 70. It optimizes access to and flow of the sterilizing agent onto the actuating ring 71. Indeed, the autoclave is a hot steam bath, and it is essential to prevent steam from becoming trapped in the mechanism, particularly during drying. This can cause condensation of the fluid and form a pocket of liquid inside the system (liquid that cannot escape quickly becomes stagnant water and is therefore unsuitable for medical use).

Claims

1. Demands Tool changing system (50) for a robotic arm (13) of a medical robot (10), the tool changing system (50) comprising a fixed part (60) intended to be permanently positioned at a distal end of the robotic arm (13) and a removable part (70) comprising a tool (80) adapted to assist a practitioner during a minimally invasive medical procedure, the removable part (70) being replaceable to change the tool, the fixed part (60) comprising: - a chassis (61), - a locking pin (62) of generally cylindrical shape, the surface of which has at least one recess (63), - at least one positioning pin (64), the removable part (70) comprising: - a connecting piece (74) comprising a tubular wall (75) adapted to receive the locking stud (62), the tubular wall (75) comprising at least one radial opening (76), the connecting piece (74) comprising at least one orifice (77) intended to cooperate with said at least one positioning pin (64), - an actuation ring (71) comprising at least one slope (73) on its internal surface (72), - at least one locking element (78) housed at said at least one radial opening (76) between the internal surface (72) of the actuating ring (71) and the tubular wall (75) of the connecting piece (74), The tool-changing system (50) is configured such that, when the fixed part (60) and the removable part (70) are assembled with each other so that said at least one positioning pin (64) is housed in said at least one orifice (77), a rotational movement of the actuating ring (71) relative to the locking pin (62) allows a transition from an unlocked position to a locked position by a push of the locking element (78) by said at least slope (73) of the ring actuation (71), along a radial axis, in said at least one recess (63) of the locking pin (62), the tool changing system (50) being characterized in that the connecting piece (74) of the removable part (70) has at least one additional radial opening (79) which is not associated with a locking element (78) and which allows the passage of a sterilizing fluid between the tubular wall (75) of the connecting piece (74) and the internal surface (72) of the actuating ring (71).

2. Tool changing system (50) according to claim 1 wherein the fixed part (60) and the removable part (70) each have at least one visual marker (65a, 65b) indicating the locked position or the unlocked position when the fixed part (60) and the removable part (70) are assembled with each other and said visual markers (65a, 65b) are opposite each other.

3. Tool changing system (50) according to any one of claims 1 to 2 wherein the tool (80) and the actuating ring (71) each have at least one optical marker.

4. Tool changing system (50) according to any one of claims 1 to 3 wherein the removable part (70) has at least one NFC tag, and the fixed part (60) has at least one NFC reader configured to receive information transmitted by said at least one NFC tag of the removable part (70) when the fixed part (60) and the removable part (70) are assembled together and the actuating ring (71) is in the locked position.

5. Tool changing system (50) according to any one of claims 1 to 4 wherein the tool (80) comprises a guiding device (81) for a medical instrument (15) such as a needle, probe, electrode, catheter, screw, drill bit or trocar.

6. A tool changing system (50) according to any one of claims 1 to 5, further comprising a sterile drape (90) intended to cover at least the robotic arm (13) of the medical robot (10), the sterile drape (90) having a circular opening the periphery of which is formed by a ring (91) intended to enclose a shoulder (67) of the chassis (61) of the fixed part (60), said shoulder (67) being configured to be covered by the actuating ring (71) when the fixed part (60) and the removable part (70) are assembled together, the ring (91) then being held between the shoulder (67) and the actuating ring (71).

7. Tool changing system (50) according to claim 6 wherein the sterile drape (90) has an NFC tag, the fixed part (60) has an NFC reader configured to receive information transmitted by the NFC tag of the sterile drape (90) when the ring (91) of the sterile drape clamps the shoulder (67) of the frame (61) of the fixed part (60).

8. Medical robot (10) comprising a robotic arm (13) and a tool changing system (50) according to any one of claims 1 to 7.

9. Medical robot (10) according to claim 8 comprising a control unit (12) of the robotic arm (13), and wherein the fixed part (60) of the tool changing system (50) comprises a display screen (66) connected to the control unit (12) and taking the form of a flexible band wrapped around the chassis (61) of the fixed part (60).

10. Medical robot (10) according to claim 9 wherein the control unit (12) is configured to display on the display screen (66) an indication relating to the control of the robotic arm (13).

11. Medical robot (10) according to any one of claims 8 to 10, wherein the tool (80) and the actuating ring (71) of the removable part (70) of the tool changing system (50) each have at least one optical marker, and wherein the control unit (12) is configured to: - receive information from an optical navigation system (30) relating to the positions of the optical markers of the tool (80) and the actuating ring (71), - check, based on the position information of the optical markers, whether the actuating ring (71) is in the locked position.

12. Medical robot (10) according to claim 8, wherein the tool changing system (50) is according to claim 7, and the control unit (12) is configured to check, depending on whether or not the information transmitted by the NFC tag of the sterile drape (90) has been received, whether the sterile drape (90) is correctly positioned on the fixed part (60) of the tool changing system (50).

13. Medical robot (10) according to claim 8, wherein the tool-changing system (50) is according to claim 4, and the unit control unit (12) is configured to check, based on the information transmitted by said at least one NFC tag of the removable part (70), whether the tool (80) is suitable for a minimally invasive medical intervention planned and memorized by the control unit (12).

14. Medical robot (10) according to claim 8, wherein the tool changing system (50) is according to claim 4, calibration data previously determined for different removable parts are stored in the control unit (12) or are accessible by the control unit (12), the information transmitted by the NFC tag of the removable part (70) includes an identifier of the removable part (70), and the control unit (12) is configured to select, from said identifier, calibration data to be used to control the robotic arm (13).

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