Control of a robotic system actuator for driving an elongated flexible medical instrument

Abstract

This method (200) is intended for controlling an actuator kinematically connected to a drive element adapted to come into contact with an elongated flexible medical instrument so as to control the movement of said drive element about an axis. It comprises measuring (206) a force exerted by the medical instrument on the drive element about the axis, transmitting (214) to the actuator a primary control signal adapted to converge the speed of movement of the drive element about the axis towards a predetermined speed setpoint as long as the measured force is below a predetermined threshold, and transmitting (216) to the actuator a secondary control signal adapted to converge the measured force towards a predetermined force setpoint when the measured force exceeds said threshold. Figure for the abstract: Fig. 6

Description

Title of the invention: Control of a robotic system actuator for driving an elongated flexible medical instrument. Field of the invention

[0001] The present invention relates to robotic systems for driving elongated flexible medical instruments such as guides, catheters, etc., used particularly in angioplasty procedures. It relates more specifically to the control of the actuators of such a robotic system. Technological background

[0002] Angioplasty with manual insertion of an elongated, flexible medical instrument such as a catheter or guidewire into a patient is a relatively standard medical procedure. However, since this procedure is monitored by X-ray angiography, the practitioner performing the procedure is exposed to significant radiation if they carry out such an operation on numerous patients.

[0003] In order to reduce the risks to the practitioner, it has been proposed to automate such insertion by means of robotic systems comprising clamping elements, moved by actuators, that can move closer together and further apart to respectively clamp or release said medical instrument, said clamping elements, once brought close together so as to clamp the medical instrument, being able to perform: - a synchronous longitudinal translation to advance or retract the medical instrument, and / or - opposing transverse translations to rotate the medical instrument around its axis of elongation.

[0004] Such a robot is known for example from FR 3 044 541.

[0005] The clamping force applied by the clamping elements of these robotic systems must satisfy two opposing constraints. On the one hand, it must be sufficient to allow the medical instrument to be driven without slippage. On the other hand, it must not be too high to avoid ovalization of the medical instrument, that is, a change in the cross-section of said medical instrument, which, from being circular when new, would become oval or elliptical under the effect of the clamping force. Such ovalization is indeed problematic when driving the medical instrument in rotation because it can impede the correct rotation of the medical instrument, as described in WO 2022 / 219165.

[0006] Generally, to move the clamping elements from their extended position to their extended position, the actuators are controlled by means of a control law aimed at moving the components to a predetermined position, depending on the type of medical instrument being handled, which must have been previously specified by the robot operator. The clamping components are then held in this position as long as they are in a phase during which they must grip the medical instrument. However, this often leads to ovalization of the medical instrument.

[0007] To solve this problem, it was proposed in WO 2022 / 219165 to equip these robotic systems with sensors that measure the clamping force and a regulator that maintains the clamping force between a minimum and a maximum threshold. Thus, when the actuators are in a close position, their clamping force is regulated.

[0008] However, this solution is not entirely satisfactory. Indeed, WO 2022 / 219165 does not detail how this control of the clamping force of the clamping elements is coordinated with the control of the movement of the clamping elements from their extended position to their extended position. However, the inventors realized that it was difficult to control this movement of the clamping elements in such a way as to reconcile compliance with the maximum clamping force threshold and the speed of movement of the clamping elements. Description of the invention

[0009] One objective of the invention is to enable rapid movement, along a direction of travel, of a drive element intended to come into contact with an elongated flexible medical instrument, while preventing the force exerted by the drive element on the elongated flexible medical instrument along the direction of travel from exceeding a predetermined threshold. Other objectives are to prevent damage to the medical instrument and to enable slip-free movement of the medical instrument by the drive element.

[0010] To this end, the invention relates, according to a first aspect, to a method for controlling a robotic system for driving, in translation and / or rotation, an elongated flexible medical instrument, the robotic system comprising a drive element adapted to come into contact with the elongated flexible medical instrument and kinematically connected to the actuator so that the latter controls the movement of said drive element along a so-called main axis, the control method being implemented by a data processing unit and comprising the following steps: - measurement of a speed of movement of the drive element along the main axis, - measurement of the force exerted by the elongated flexible medical instrument on the drive organ along the main axis, and - displacement of the drive element along the main axis, in a first direction, with: • transmission to the actuator of a primary control signal adapted to converge the measured movement speed towards a predetermined speed setpoint as long as the measured force is below a predetermined non-zero force threshold, and • transmission to the actuator of a secondary control signal adapted to make the measured force converge towards a predetermined force setpoint when the measured force exceeds said force threshold.

[0011] According to particular embodiments of the invention, the control method also has one or more of the following characteristics, taken individually or in any technically possible combination(s): - the main axis consists of a clamping axis for the elongated flexible medical instrument, the first direction being oriented towards the elongated flexible medical instrument; - The process includes the following additional steps: • measurement of the position of the drive element along the main axis, and • displacement of the drive element along the main axis in a second direction opposite to the first direction, with transmission to the actuator of a tertiary control signal adapted to converge the measured position towards a predetermined position setpoint; - the process includes, between the displacement steps in the first direction and in the second direction, an additional step of immobilizing the drive element along the main axis during which a quaternary control signal adapted to maintain the measured force substantially equal to the force setpoint is transmitted to the actuator; - the process includes, during the step of immobilizing the drive element along the main axis, the displacement of the drive element along at least one axis orthogonal to the main axis; - the movement steps in the first direction and in the second direction are implemented one after the other, in a cyclical, repeated manner; - the measured position is deduced from a current position of the actuator; - the process includes an additional step of measuring a position of the drive unit along the main axis, the speed setpoint having a first value as long as the measured position is below a predetermined position threshold and a second value, lower than the first value, when the measured position is above said position threshold; - the position threshold is such that when the measured position is equal to said position threshold the drive organ is not in contact with the elongated flexible medical instrument; - the force setting is higher than the force threshold; - the measured speed of movement is deduced from a current speed of the actuator; - the measured force is deduced from a current power supply to the actuator; - the measured force is measured directly by a strain sensor; and - the elongated flexible medical instrument consists of a catheter or a catheter guide.

[0012] The invention also relates, according to a second aspect, to a robotic system for training an elongated flexible medical instrument, said robotic system comprising a frame, a drive element adapted to come into contact with the elongated flexible medical instrument, an actuator kinematically connected to the drive element so as to control the movement of said drive element relative to the frame along a main axis, and a data processing unit for implementing a method according to the first aspect.

[0013] The invention also relates, according to a third aspect, to a computer program product comprising code instructions for the implementation of a control method according to the first aspect when said computer program product is executed by a processor of a data processing unit of a robotic system for the drive of an elongated flexible medical instrument.

[0014] The invention also relates, according to a fourth aspect, to a means of storage readable by a computer equipment on which a computer program product is recorded according to the third aspect. Brief description of the Figures

[0015] Other features and advantages of the invention will become apparent from the following description, given solely by way of example and with reference to the accompanying drawings, in which: - Fig. 1 is a schematic side view of an example of an angioplasty installation comprising a robotic system according to an embodiment of the invention, - [Fig.2] is a schematic perspective view of the robotic system of the installation of [Fig.1], Figures 3A to 3E schematically represent several successive stages of rotational training of an elongated flexible medical instrument. by the robotic system of [Fig.2], - Figures 4A to 4G schematically represent several successive stages of translational training of an elongated flexible medical instrument by the robotic system of [Fig.2], - [Fig.5] is a functional diagram of a control unit of the robotic system of [Fig.2], - [Fig. 6] is a diagram illustrating a method for controlling actuators of the robotic system of [Fig. 2], and - [Fig.7] is a diagram illustrating the evolution over time of various parameters of the robotic system of [Fig.2] when the control process of [Fig.6] is applied. Detailed description of an example of implementation

[0016] The angioplasty installation 1 shown in [Fig.1] includes a robot 3 for introducing an elongated flexible medical instrument 5 into an anatomical conduit of a patient 7, typically into a blood vessel of said patient 7. It also includes an angiography system 10 to track the movement of the medical instrument 5 inside the body of the patient 7.

[0017] The angioplasty unit 1 is here distributed between an operating room 12 and a control room 14. In one embodiment, this control room 14 is close to the operating room 12 and is, for example, separated from it by a simple X-ray opaque wall 16. In another embodiment, the control room 14 is located away from the operating room 12. Alternatively (not shown), the angioplasty unit 1 is entirely located within the operating room 12 alone.

[0018] The robot 3 includes a robotic system 20 for driving the medical instrument 5, placed in the operating room 12 near the patient 7.

[0019] The robot 3 also includes a control station 22 for the operation of the robotic system 20 by an operator. Here, this control station 22 is a remote control station located in the control room 14 and communicating with the robotic system 20 via a communication box 24 connected to the robotic system 20.

[0020] In the example shown, the robot 3 also includes a local control box 26, located in the operations room 12, for the control of the robotic system 20 by an operator directly from the operations room 12.

[0021] The angiography system 10 includes a medical imager 30, in particular an X-ray imager, comprising a source 32 and a detector 34 arranged on either side of the patient 7, possibly movable relative to the patient 7.

[0022] The angiography system 10 also includes at least one screen 36, 38 communicating with the imager 30 for real-time display of the images acquired by the imager 30. Here, the screens 36, 38 include a remote screen 36 installed in the control room 14 and a local screen 38 installed in the operating room 12. Alternatively (not shown), the angiography system 10 includes only the remote screen 36 or the local screen 38.

[0023] The angiography system 10 further includes at least one control 40, 42 communicating with the imager 30 to control the image acquisition by the imager 30. Here, the controls 40, 42 include a remote control 40 installed in the control room 14 and a local control 42 installed in the operating room 12. Alternatively (not shown), the angiography system 10 includes only the remote control 40 or the local control 42.

[0024] The angiography system 10 further comprises a contrast agent injector 44 for injecting a contrast agent into the medical instrument 5 to facilitate imaging of said medical instrument 5, a fitting 46 connecting the injector 44 to the medical instrument 5 to guide the contrast agent from the injector 44 into the medical instrument 5, and at least one control 47, 48 for controlling the injector 44. Here, the controls 47, 48 comprise a remote control 47 installed in the control room 14 and a local control 48 installed in the operating room 12. Alternatively (not shown), the angiography system 10 comprises only the remote control 47 or the local control 48.

[0025] The elongated flexible medical instrument 5 is elongated along an axis of elongation. It consists of a medical instrument capable of being inserted into an anatomical conduit, typically a blood vessel, of the patient 7, and of being moved within said anatomical conduit through a sheath providing an access opening in the patient 7. This elongated flexible medical instrument 5 is typically a catheter or a catheter guidewire.

[0026] A catheter is, as is known, made up of a flexible and elongated tube, which is generally hollow over a portion close to the patient 7, or even along its entire length. Optionally, the catheter is equipped, at its distal end (opposite the robot 3), with a medical device such as a balloon, an endoprosthesis, etc.

[0027] A guidewire is, in a known manner, a medical instrument configured to guide the catheter to an implantation site in the patient's body 7. For this purpose, the guidewire is generally a cylinder with a transverse diameter smaller than that of the catheter, so that the catheter can be placed around the guidewire and slide along it under the effect of a force initiated by the robot 3 or by an operator until its free end reaches the desired implantation site. Optionally, the guidewire has a curved end to facilitate its navigation through the patient's bloodstream 7.

[0028] To move the elongated flexible medical instrument 5 inside the patient's body 7. It is desirable to be able to translate said instrument 5 along its axis of elongation and to be able to rotate it around said axis of elongation. Reference may be made to document FR 3 044 541 for further details regarding the usefulness of these movements.

[0029] The robotic system 20 is configured to drive the elongated flexible medical instrument 5 so as to give it at least one of these movements, here both.

[0030] For this purpose, the robotic system 20 comprises, with reference to [Fig.2], a frame 50 and at least one, here two, drive module(s) 52, 52' each configured to drive the medical instrument 5 relative to the frame 50: - in translation along an X, X' axis of extension of the medical instrument 5 at the level of said training module 52, 52' here referred to as the longitudinal axis, and - in rotation around said longitudinal axis X, X'.

[0031] It will be noted that said longitudinal axis X, X' is most often different from the extension axis of the medical instrument 5 at the level of its distal end; nevertheless, a translation and / or a rotation of the medical instrument 5 along / around the longitudinal axis X, X', therefore along / around its elongation axis at the level of the robotic system 20 will result in a translation and / or a rotation of the medical instrument 5, respectively, along / around its elongation axis at the level of its distal end.

[0032] In the example shown, each drive module 52, 52' comprises a pair of drive members 54, 56 forming together a gripper configured to grasp and move the medical instrument 5 relative to the frame 50.

[0033] For this purpose, at least one of said drive members 54, 56, here each of the drive members 54, 56, is mounted movable in translation relative to the frame 50 along a clamping axis Y, Y' orthogonal to the longitudinal axis X, X' and substantially intersecting the axis of the medical instrument 5. The drive members 54, 56 are movable relative to each other along this clamping axis Y, Y' between a distant position, in which the drive members 54, 56 are at a distance from each other, and a close position in which the drive members 54, 56 are close to each other.

[0034] Each drive member 54, 56 of a pair is also movable in translation relative to the frame 50 along at least one other axis substantially orthogonal to the clamping axis Y, Y'. Each drive member 54, 56 of a pair is thus movable in translation relative to the frame 50 along at least one of the following axes: - the longitudinal axis X, X', and - a transverse axis Z, Z' substantially orthogonal to the clamping axes Y, Y' and longitudinal X, X'.

[0035] The two drive members 54, 56 of each drive module 52, 52' have in particular the same degrees of freedom along the longitudinal axis X, X', That is to say, for each drive module 52, 52', one of whose drive members 54, 56 is translationally movable along the longitudinal axis X, X', the other drive member 54, 56 of said drive module 52, 52' is also translationally movable along said longitudinal axis X, X'. Advantageously, the two drive members 54, 56 of each drive module 52, 52' also have the same degrees of freedom along the transverse axis Z, Z'.

[0036] Here, each drive member 54, 56 of each drive module 52, 52' is movable in translation relative to the frame 50 along each of the longitudinal axis X, X' and transverse axis Z, Z'.

[0037] Preferably, the drive modules 52, 52' are arranged so that the longitudinal axes X, X' are, as shown, substantially coincident. For the sake of simplicity, reference will therefore be made to the longitudinal axis X, the clamping axis Y, and the transverse axis Z.

[0038] Each drive element 54, 56 defines a drive surface, respectively 58, 59, configured to be away from the medical device 5 when the drive elements 54, 56 are in the extended position and in contact with the medical device 5 when the drive elements 54, 56 are in the extended position. These drive surfaces 54, 56 face each other and are spaced apart along the Y-axis. Each drive surface 58, 59, in particular, has a normal substantially parallel to the Y-axis.

[0039] Each drive element 54, 56 is typically formed of a key holder (not shown) and a removable key (not shown) mounted on the key holder and delimiting the drive surface 58, 59. The drive surface 58, 59 in contact with the medical instrument 5 can thus be changed with each use of the robot 3, which makes it possible to preserve the sterility of the medical instrument 5.

[0040] Each drive module 52, 52' also includes a drive device 60 for controlling the movement of the drive members 54, 56 of said module 52, 52' along the Y axis and, where applicable, the X and / or Z axis. This drive device 60 includes at least one actuator 62, 63, 64, 65, 66, 67 and, for each actuator 62, 63, 64, 65, 66, 67, a kinematic chain 72, 73, 74, 75, 76, 77 respectively, kinematically linking said actuator 62, 63, 64, 65, 66, 67 to at least one of the drive members 54, 56 so that the latter controls the movement of said drive member 54, 56 along at least one of the X, Y, Z axes.

[0041] According to one possible embodiment, as shown, each kinematic chain 72, 73, 74, 75, 76, 77 kinematically connects an actuator 62, 63, 64, 65, 66, 67 to only one of the drive members 54, 56. Each actuator 62, 63, 64, 65, 66, 67 thus controls the movement of only one of the drive members 54, 56. The device The drive unit 60 is thus formed of two drive sub-devices 80, 82, each specific to one of the drive elements 54, 56.

[0042] Here, each drive sub-device 80, 82 comprises three actuators, respectively 62, 63, 64 and 65, 66, 67. Each actuator 62, 63, 64, 65, 66, 67 contributes to the movement of the drive member, respectively 54, 56, along at least one of the X, Y, Z axes. Advantageously, each actuator 62, 63, 64, 65, 66, 67 contributes to the movement of the drive member, respectively 54, 56, along a single axis, specific to said actuator 62, 63, 64, 65, 66, 67, among the X, Y, Z axes or, failing that, has a majority contribution along an axis, specific to said actuator 62, 63, 64, 65, 66, 67, among the X, Y, Z axes, that is to say, the contribution of said actuator 62, 63, 64, 65, 66, 67 to the displacement of the drive element 54, 56 along said proper axis is large compared to the contribution of the actuator 62, 63, 64, 65, 66, 67 to the displacement of the drive element 54, 56 along each of the other axes. Thus, in the example shown: - the actuators 62, 65 contribute mainly or exclusively to the movement of the drive elements 54, 56 along the X axis, - the actuators 63, 66 contribute mainly or exclusively to the movement of the drive elements 54, 56 along the Y axis, and - the actuators 64, 67 contribute mainly or exclusively to the movement of the drive elements 54, 56 along the Z axis.

[0043] For this purpose, each drive sub-device 80, 82 is typically constituted by a drive device as described in WO 2022 / 144267.

[0044] Each actuator 62, 63, 64, 65, 66, 67 consists for example of an electric motor comprising a rotor and a stator (not shown), the stator being fixed relative to the frame 50 and the rotor forming the part of the actuator 62, 63, 64, 65, 66, 67 kinematically connected to the drive member 54, 56.

[0045] The robotic system 20 also includes sensors 84, 85 for measuring a clamping force, a travel speed and a position of the drive members 54, 56 of each module 52, 52' along the Y axis. Here, the robotic system 20 also includes sensors 87, 88 for also measuring a position of the drive members 54, 56 of each module 52, 52' along each of the X and Z axes.

[0046] The sensors 84, 85, 87, 88 are indirect sensors, meaning that they provide representative data on the clamping force, the speed of movement along the Y-axis, and the position of the drive elements 54, 56 of each module 52, 52' by indirect measurements, in this case by measurements on the actuators 62, 63, 64, 65, 66, 67. These indirect measurements are, for example, a measurement of the supply current to the actuators 62, 63, 64, 65, 66, 67 and a measurement of the Position of actuators 62, 63, 64, 65, 66, 67 (typically, in the case of electric motors, the position of the rotor relative to the stator). It is indeed known that there are transfer functions relating: - the electrical power consumed by an actuator compared to the force exerted by a component driven by said actuator, - the speed of an actuator relative to the speed of movement of a component driven by said actuator, and - the position of an actuator relative to the position of a component driven by said actuator,

[0047] These transfer functions depend on the kinematic chain linking the actuator to the component it drives. A person skilled in the art will readily be able to identify these transfer functions in order to deduce the clamping force, the speed of movement along the Y-axis, and the position of the drive components 54, 56 of each module 52, 52' from the measurements provided by the sensors 84, 85, 87, 88.

[0048] In an alternative (not shown), the sensors 84, 85, 87, 88 are direct sensors, that is to say they directly measure the clamping force, the speed of movement along the Y axis and the position of the drive elements 54, 56 of each module 52, 52'.

[0049] The robotic system 20 further includes a control unit 90 for the actuators 62, 63, 64, 65, 66, 67 of each drive module 52, 52', suitable for transmitting to each of said actuators 62, 63, 64, 65, 66, 67 a control signal for the latter.

[0050] This control unit 90 is here realized in the form of a data processing unit comprising a processor or CPU (“Central Processing Unit”) 92, a memory 94 of type RAM (“Random Access Memory”) and / or ROM (“Read Only Memory”), and a storage module 96 of type internal storage.

[0051] The storage module 96 is for example of the type HDD (“Hard Disk Drive” in English) or SSD (“Solid-State Drive” in English), or of the type of external storage media reader, such as an SD card reader (“Secure Digital” in English).

[0052] The processor 92 is configured to store data, or information, in memory 94 or in storage module 96 and / or read data stored in memory 94 or in storage module 96.

[0053] The processor 92 is configured to execute instructions loaded into memory 94, for example from the storage module 96. When the robotic system 20 is powered on, the processor 92 is able to read instructions from memory 94 and execute them. These instructions form a computer program causing the processor 92 to implement all or part of a method 200 for controlling the actuators 62, 63, 64, 65, 66, 67, which will be described later. far away. Thus, all or part of process 200 can be implemented in software form by executing a set of instructions by a programmable machine, such as a DSP (Digital Signal Processor) or a microcontroller.

[0054] In an alternative (not shown), the control unit 90 is implemented in the form of a data processing unit consisting at least in part of a dedicated machine or component, such as an FPGA (Field-Programmable Gate Array) or an ASIC (Application-Specific Integrated Circuit), to implement all or part of the process 200.

[0055] It will be noted that, although represented here as a single unit common to all actuators 62, 63, 64, 65, 66, 67, the control unit 90 can alternatively be made in the form of several units distributed at the level of each drive device 60 or at the level of each sub-device 80, 82, or even at the level of each actuator 62, 63, 64, 65, 66, 67, said distributed units then being synchronized by means of a shared synchronization signal.

[0056] The control unit 90 is specifically configured to control the actuators 62, 63, 64, 65, 66, 67 so as to rotate the medical instrument 5 around its elongation axis by simultaneously moving, in opposite directions, the drive members 54, 56 of the same pair along the Z-axis. To this end, the control unit 90 is typically configured to control the implementation of the following steps, illustrated in Figures 3A to 3E: - positioning of the drive elements 54, 56 in a spread-out position, their respective drive surfaces 58, 59 not being in contact with the medical instrument 5 ([Fig.3A]); - bringing the drive members 54, 56 closer together by translating said members 54, 56 in opposite directions along the Y axis, until their respective drive surfaces 58, 59 come together to enclose the medical instrument 5 ([Fig.3B]); - displacement of the drive elements 54, 56 in translation along the Z axis, in opposite directions to each other, so as to rotate the medical instrument 5 around its axis in one direction or the other, the drive surfaces 58, 59 keeping the medical instrument 5 clamped during this displacement ([Fig.3C]); - moving the drive elements 54, 56 away from the medical instrument 5 by translating said elements 54, 56 in opposite directions along the Y axis, until reaching a predetermined position in which the drive surfaces 58, 59 release the medical instrument 5 and cease to be in contact with the medical instrument 5 ([Fig. 3D]); and - repositioning of the drive components 54, 56 by translation of said components organs 54, 56 in opposite directions along the Z axis, their respective drive surfaces 58, 59 remaining away from the medical instrument 5 so as not to cause the medical instrument 5 to rotate, until the drive organs 54, 56 return to their original position ([Fig.3E] )•

[0057] The control unit 90 is in particular configured to control the cyclic repetition of these steps, so as to allow a complete rotation of the medical instrument 5 in both directions.

[0058] The control unit 90 is also configured to control the actuators 62, 63, 64, 65, 66, 67 so as to drive the translation of the medical instrument 5 along its axis by simultaneous displacement, in the same direction, of the drive members 54, 56 of the same pair along the X-axis. To this end, the control unit 90 is typically configured to control the implementation of the following steps, illustrated in Figures 4A to 4G: - positioning of the drive elements 54, 56 of each drive module 50, 50' in a spread-out position, their respective drive surfaces 58, 59 not being in contact with the medical instrument 5 ([Fig.4A]); - bringing the drive elements 54, 56 of a first drive module 50 closer together by translating said elements 54, 56 in opposite directions along the Y axis, until their respective drive surfaces 58, 59 come to enclose the medical instrument 5, the drive elements 54, 56 of the second drive module 50' remaining away from the medical instrument 5 ([Fig.4B]); - displacement of the drive members 54, 56 of the first drive module 50 in translation along the X axis, synchronously and in the same first direction, so as to drive the medical instrument 5 in translation along its axis in said first direction, the drive surfaces 58, 59 of the first drive module 50 keeping the medical instrument 5 clamped during this displacement, while the drive members 54, 56 of the second drive module 50' remain immobile away from the medical instrument 5 ([Fig.4C]); - moving the drive elements 54, 56 of the first drive module 50 away from the medical instrument 5 by translating said elements 54, 56 in opposite directions along the Y axis, until reaching a predetermined position in which the drive surfaces 58, 59 of said elements 54, 56 release the medical instrument 5 and cease to be in contact with the medical instrument 5, and simultaneously bringing the drive elements 54, 56 of the second drive module 50' closer by translation of said organs 54, 56 in opposite directions along the Y axis, until their respective drive surfaces 58, 59 come to grip the medical instrument 5 ([Fig.4D]); - displacement of the drive members 54, 56 of the second drive module 50' in translation along the X axis, synchronously and in the first direction, so as to drive the medical instrument 5 in translation along its axis in the first direction, the drive surfaces 58, 59 of the second drive module 50' holding the medical instrument 5 during this displacement, and simultaneous displacement of the drive members 54, 56 of the first drive module 50 in translation along the X axis, synchronously and in the second direction, their respective drive surfaces 58, 59 remaining away from the medical instrument 5 so as not to drive the medical instrument 5, until the drive members 54, 56 of the first drive module 50 return to their original position ([Fig.4E]); - moving the drive elements 54, 56 of the second drive module 50' away from the medical instrument 5 by translating said elements 54, 56 in opposite directions along the Y axis, until reaching a predetermined position in which the drive surfaces 58, 59 of said elements 54, 56 release the medical instrument 5 and cease to be in contact with the medical instrument 5, and simultaneously bringing the drive elements 54, 56 of the first drive module 50 closer by translating said elements 54, 56 in opposite directions along the Y axis, until their respective drive surfaces 58, 59 come to grip the medical instrument 5 ([Fig.4F]); - displacement of the drive members 54, 56 of the first drive module 50 in translation along the X axis, synchronously and in the first direction, so as to drive the medical instrument 5 in translation along its axis in the first direction, the drive surfaces 58, 59 of the first drive module 50 holding the medical instrument 5 during this displacement, and simultaneous displacement of the drive members 54, 56 of the second drive module 50' in translation along the X axis, synchronously and in the second direction, their respective drive surfaces 58, 59 remaining away from the medical instrument 5 so as not to drive the medical instrument 5, until the drive members 54, 56 of the second drive module 50' return to their original position ([Fig.4G]).

[0059] The control unit 90 is preferably configured to control the repetition cyclical steps of Figures 4D to 4G, so as to allow the lengthening of the displacement stroke of the medical instrument 5 along the X axis.

[0060] The control unit 90 is in particular configured so that, when the drive members 54, 56 are brought together, i.e. during the steps illustrated by Figures 3B, 4B, 4D and 4F, the clamping force exerted by the drive members 54, 56 does not exceed a predetermined limit threshold.

[0061] For this purpose, the control unit 90 comprises, for each drive sub-device 80, 82, a control sub-unit 98 of said sub-device 80, 82. With reference to [Fig.5], this control sub-unit 98 comprises a control module 100 of the actuators 62, 63, 64, 65, 66, 67 in position, a control module 102 of the actuators 62, 63, 64, 65, 66, 67 in speed and a control module 104 of the actuators 62, 63, 64, 65, 66, 67 in force.

[0062] The position control module 100 comprises a first input 110 for receiving a predetermined position command along each of the axes of movement of the drive element 54, 56 driven by the sub-device 80, 82 (therefore, here, along each of the X, Y, and Z axes) and a second input 112 for receiving a measurement of the position of said drive element 54, 56 along each of its axes of movement (therefore, here, along each of the X, Y, and Z axes). The position control module 100 is configured to generate, based on these inputs, for each of the axes of movement of the drive element 54, 56, a suitable position control signal to converge the measured position along said axis of movement to the corresponding position command.It also includes, for each axis of movement of the drive member 54, 56, a respective output 114, 116, 188 to transmit to each relevant actuator 62, 63, 64, 65, 66, 67 (i.e. to each actuator acting on the movement of the drive member along said axis of movement) this position control signal. Thus, in the example shown, the said outputs 114, 116, 118 include: - a first output 114 for the transmission to each of the actuators 62, 63, 64, 65, 66, 67 concerned of a position control signal adapted to make the measured position along the X axis converge towards the position setpoint along the X axis, - a second output 116 for the transmission to each of the actuators 62, 63, 64, 65, 66, 67 concerned of a position control signal adapted to make the measured position along the Y axis converge towards the position setpoint along the Y axis, and . - a third output 118 for transmitting to each relevant actuator 62, 63, 64, 65, 66, 67 a control signal in a suitable position to converge the measured position along the Z axis towards the setpoint of position along the Z axis.

[0063] The speed control module 102 includes a first input 120 for receiving a speed command along the clamping axis Y and a second input 122 for receiving a speed measurement of the drive element 54, 56 driven by the sub-device 80, 82 along the clamping axis Y. The speed control module 102 is configured to generate, based on these inputs, a speed control signal adapted to converge the measured speed towards the speed command. It also includes an output 124 for transmitting this speed control signal to each relevant actuator 62, 63, 64, 65, 66, 67 (i.e., to each actuator acting on the movement of the drive element along the clamping axis Y).

[0064] The force control module 104 includes a first input 130 for receiving a predetermined force setpoint along the clamping axis Y and a second input 132 for receiving a measurement of the force exerted by the medical instrument 5 on the drive member 54, 56 driven by the sub-device 80, 82 along the clamping axis Y. The force control module 104 is configured to generate, based on these inputs, a force control signal adapted to converge the measured force towards the force setpoint. It also includes an output 134 for transmitting this force control signal to each relevant actuator 62, 63, 64, 65, 66, 67 (i.e., to each actuator acting on the displacement of the drive member along the clamping axis Y).

[0065] The force setting is strictly less than the limit threshold. For example, it is less than 90% of the limit threshold, preferably between 80 and 90% of the limit threshold.

[0066] The control subunit 98 also includes a switch 140 for switching the control of the actuators 62, 63, 64, 65, 66, 67 in clamping mode between position control, speed control, and force control. For this purpose, the switch 140 includes a first input 142 for receiving the position control signal, a second input 143 for receiving the speed control signal, and a third input 144 for receiving the force control signal. It also includes an output 145 for transmitting a clamping control signal to each relevant actuator 62, 63, 64, 65, 66, 67 (i.e., to each actuator acting on the movement of the drive element along the clamping axis Y).The switch 140 further includes a fourth input 146 for receiving a measurement of the force exerted by the medical instrument 5 on said drive member 54, 56 along the clamping axis Y and a fifth input 147 for receiving information regarding the current phase of movement along the clamping axis Y (movement of the drive members 54, 56 towards or away from each other). The com. Switch 140 is configured to selectively connect output 145 to the first, second, or third input 142, 143, 144, depending on the fourth and fifth inputs 146, 147. In particular, switch 140 is configured to switch between three configurations: - a first configuration in which it connects the output 145 to the first input 142, that is to say it transmits as a clamping signal the position control signal to the relevant actuators 62, 63, 64, 65, 66, 67, when the fifth input 147 indicates that the current movement phase along the clamping axis Y is a phase of spreading the drive members 54, 56 (that is to say typically during the steps illustrated by Figures 3D, 4D and 4F), regardless of the value of the fourth input 146; - a second configuration in which it connects output 145 to the second input 143, i.e., it transmits the speed control signal as a clamping signal to the relevant actuators 62, 63, 64, 65, 66, 67, when the fifth input 147 indicates that the current movement phase along the clamping axis Y is a phase of bringing the drive elements 54, 56 closer together and that the measured clamping force received on the fourth input 146 is less than or equal to a predetermined switching threshold; and - a third configuration in which it connects output 145 to the third input 144, i.e. it transmits as a clamping signal the force control signal to the relevant actuators 62, 63, 64, 65, 66, 67, when the fifth input 147 indicates that the current movement phase along the clamping axis Y is a phase of bringing the drive members 54, 56 closer together and that the measured clamping force received on the fourth input 146 is strictly greater than the predetermined switching threshold.

[0067] The predetermined switching threshold is strictly less than the force setpoint.

[0068] The clamping signal is typically constituted by an electrical signal controlling, for each actuator 62, 63, 64, 65, 66, 67 concerned, the switching of the power switches of a power supply element of said actuator 62, 63, 64, 65, 66, 67.

[0069] The control subunit 98 further includes a speed setpoint generator 150. This generator 150 includes an input 152 for receiving a measurement of the position of the drive element 54, 56 driven by the sub-device 80, 82 along the clamping axis Y and an output 154 for transmitting the speed setpoint to Speed ​​control module 102. Generator 150 is configured to compare the measured position to a predetermined position threshold and to assign to the speed setpoint a first predetermined value when the measured position is less than or equal to the position threshold and a second predetermined value, strictly less than the first value, when the measured position is strictly greater than the position threshold.

[0070] The second speed setpoint value is preferably less than 90% of the first value, for example less than 60%, advantageously between 60 and 40% of the first value. Furthermore, the second value is preferably less than the achievable speed of the drive element 54, 56 as it moves from its original position to the position threshold.

[0071] The position threshold is such that when the measured position is equal to said position threshold the drive organ 54, 56 is not in contact with the medical instrument 5.

[0072] The process 200 implemented by the control unit 90 will now be described, with reference to Figures 6 and 7. For simplicity, the description given here concerns the control of only the actuators 62, 63, 64 of the same drive sub-device 80 driving a single drive element 54. A person skilled in the art will easily be able to deduce the control of the other actuators.

[0073] This method 200 first includes a force measurement step 202, a speed measurement step 204 and a position measurement step 206.

[0074] The force measurement step 202 includes measuring the force exerted by the medical instrument 5 on the drive member 54 along the clamping axis Y. This force is typically deduced, as described above, from the power supply to the actuators 62, 63, 64. Alternatively, this force is measured directly by a strain sensor.

[0075] The speed measurement step 204 includes measuring the speed of movement of the drive member 54 along the clamping axis Y. This speed is typically deduced, as described above, from the current speed of at least one of the actuators 62, 63, 64. For example, the speed of movement of the drive member 54 along the clamping axis Y is deduced from the current speed of the actuator 63 (i.e., the actuator contributing mainly or exclusively to the movement of the drive member 54 along the axis Y).

[0076] The position measurement step 206 includes measuring the position of the drive member 54 along the clamping axis Y. This position is typically deduced, as described above, from the current position of at least one of the actuators 62, 63, 64. For example, the position of the drive member 54 along the clamping axis Y is deduced from the current position of the actuator 63 (i.e., the actuator contributing mainly or exclusively to the movement of the drive element 54 along the Y axis).

[0077] These steps 202, 204, 206 are repeated throughout the implementation of the process 200, at a predetermined sampling frequency, possibly variable but preferably constant.

[0078] The process 200 then includes a step 210 of clamping the medical instrument 5. During this step 210, the control unit 90 commands the actuators 62, 63, 64 so as to bring the drive member 54 closer to the drive member 56. This step 210 is typically implemented during the steps illustrated by Figures 3B, 4B, 4D and 4F.

[0079] Step 210 first involves comparing the measured force to the switching threshold. If the measured force is less than or equal to said threshold, this comparison is followed by the transmission of a first control signal to actuators 62, 63, 64. If the measured force is strictly greater than said threshold, this comparison is followed by the transmission of a second control signal to actuators 62, 63, 64.

[0080] During transmission step 214, switch 140 is in the second configuration: the first control signal is therefore the speed control signal. This first control signal is thus adapted to bring the measured travel speed towards the speed setpoint provided by generator 150.

[0081] This transmission step 214 includes comparing 217 the measured position of the drive element 54 along the Y-axis with the position threshold. If the measured position is less than or equal to said threshold, this comparison 217 is followed by assigning 218 the first value to the speed setpoint; in other words, the generator 150 assigns the first value to the speed setpoint. If the measured position is strictly greater than said threshold, this comparison 217 is followed by assigning 219 the second value to the speed setpoint; in other words, the generator 150 assigns the second value to the speed setpoint.

[0082] After the implementation of the transmission step 214, the process 200 returns to the force comparison 212.

[0083] During transmission step 216, switch 140 is in the third configuration: the second control signal is therefore the force control signal. The second control signal is thus adapted to make the measured force converge towards the force setpoint.

[0084] The timing of this tightening step 210 is illustrated in [Fig. 7]. Step 210 begins at time t0. At this time, the drive element 54 is still in its initial position along the Y-axis; the measured position P has therefore not yet reached The SP position threshold. Furthermore, the drive unit 54 is still some distance from the medical instrument 5; the measured force F is therefore zero. Thus, the first control law is transmitted, with a speed setpoint Cv at the initial value Vb. The measured speed V therefore increases progressively, tending to converge towards the speed setpoint Cv.

[0085] However, at time tb, even before the speed V has reached the setpoint Cv, the measured position P reaches the threshold SP. The drive element 54 is then still some distance from the medical instrument 5, so the measured force F is still zero. The first control law therefore remains in effect, but the value of the speed setpoint Cv is reduced to the second value V2. Since this value is lower than the value reached by the measured speed V at time tb, the speed V gradually decreases so as to approach the new value of the speed setpoint Cv. This initiates a braking of the drive element 54.

[0086] It is during this deceleration phase that the drive element 54 comes into contact with the medical instrument 5, resulting in an increase in the measured force F, which then reaches the switching threshold SF at time t2. This has the effect of stopping the transmission of the first control law to the actuators 62, 63, 64, and the second control law is then transmitted, with a force setpoint CF equal to a value Fc which, as can be seen in [Fig. 7], is strictly less than a limit threshold Fmax that we do not wish to exceed. Under the effect of this new control law, the measured force F briefly exceeds the value Fc but without crossing the threshold Fmax, then stabilizes at the force setpoint CF.

[0087] The implementation of step 210 thus allows a rapid movement of the drive element along the clamping axis Y, without crossing the limit threshold Fmax.

[0088] Returning to [Fig.6], step 210 is followed by a step 220 of holding the medical instrument 5 tight, during which the drive member 54 is substantially immobilized along the Y axis. This step 220 is typically implemented during the steps illustrated in Figures 3C, 4C, 4E and 4G.

[0089] This step 220 includes the transmission 222 to the actuators 62, 63, 64 of a third control signal adapted to maintain the measured force substantially equal to the force setpoint. For this purpose, the switch 140 is typically maintained in its third configuration during this step 220.

[0090] Optionally, step 220 also includes the displacement 224 of the drive member 54 along the longitudinal axis X and / or the displacement 226 of the drive member 54 along the transverse axis Z. This displacement is typically obtained by superimposing on the third control signal a position control signal along the X axis and / or along the Z axis provided by the control module in position 100.

[0091] Step 220 is itself followed by a step 230 of loosening the medical instrument 5. During this step 220, the control unit 90 commands the actuators 62, 63, 64 so as to move the drive member 54 away from the drive member 56. This step 220 is typically implemented during the steps illustrated by Figures 3D, 4D and 4F.

[0092] Step 230 comprises the transmission 232 of a fourth control signal to the actuators 62, 63, 64. During step 230, the switch 140 is informed by its fifth input 147 that the drive elements 54, 56 are in a phase of separation and is therefore switched to its first configuration. Thus, the fourth control signal is the position control signal. In other words, the fourth control signal is adapted to bring the measured position towards the position setpoint.

[0093] Step 230 is followed by a step 240 of holding the medical instrument 5 loose, during which the drive member 54 is substantially immobilized along the Y axis. This step 240 is typically implemented during the steps illustrated in Figures 3E, 4E and 4G.

[0094] This step 240 includes the transmission 242 to the actuators 62, 63, 64 of a fifth control signal adapted to maintain the measured position along the Y-axis substantially equal to the position setpoint. For this purpose, the switch 140 is typically held in its initial configuration during this step 240.

[0095] Optionally, step 240 also includes the displacement 244 of the drive member 54 along the longitudinal axis X and / or the displacement 246 of the drive member 54 along the transverse axis Z. This displacement is typically obtained by superimposing on the fifth control signal a position control signal along the X axis and / or along the Z axis provided by the control module in position 100.

[0096] After step 240, process 200 finally returns to step 210, steps 210, 220, 230, 240 thus being repeated cyclically one after the other, as described above in relation to Figures 3A to 3E and 4A to 4G.

[0097] Thus, thanks to the embodiment described above, it is possible to move the drive members 54, 56 quickly along the clamping axis Y, while preventing the force exerted by the drive members 54, 56 on the medical instrument 5 along the Y axis from exceeding the limit threshold Fmax, which prevents damage to the medical instrument 5. In addition, the clamping force is maintained and controlled during step 220 of holding the medical instrument 5 clamped, which again prevents damage to the medical instrument 5 and also ensures non-slip driving of the medical instrument 5 by the drive members 54, 56.

[0098] According to a further embodiment, the drive elements are rollers rotating about the Z-axis, the rotation of said rollers about the Z-axis enabling the medical instrument 5 to be driven in translation along the X-axis. In addition, these rollers are movable in translation about the clamping axis Y in order to clamp or release the medical instrument 5. Furthermore, the rollers can be movable in translation about the Z-axis in order to drive the medical instrument 5 in rotation about the X-axis. Such a solution for the drive elements is, for example, described in the patent application filed on April 26, 2022, under number FR2203874. The clamping management described above, where the drive elements are key holders on which single-use keys are attached, can be applied similarly when the drive elements are rotating rollers.

Claims

Demands

1. Robotic system (20) for driving an elongated flexible medical instrument (5), said robotic system (200) comprising a frame (50), a drive member (54, 56) adapted to come into contact with the elongated flexible medical instrument (5), an actuator (62, 63, 64, 65, 66, 67) kinematically connected to the drive member (5) so as to control the movement of said drive member (54, 56) relative to the frame (50) along a principal axis (Y), and a data processing unit (90) for implementing a method (200) for controlling the actuator (62, 63, 64, 65, 66, 67) for driving, in translation and / or rotation, the elongated flexible medical instrument (5), the method (200) comprising the following steps: - measurement (204) of a speed of movement (V) of the drive element (54, 56) along the main axis (Y),- measurement (206) of a force (F) exerted by the elongated flexible medical instrument (5) on the drive element (54, 56) along the principal axis (Y), and - displacement (210) of the drive element (54, 56) along the principal axis (Y), in a first direction, with: • transmission (214) to the actuator (62, 63, 64, 65, 66, 67) of a primary control signal adapted to converge the measured movement speed (V) towards a predetermined speed setpoint (Cv) as long as the measured force (F) is below a predetermined non-zero force threshold (SF), and • transmission (216) to the actuator (62, 63, 64, 65, 66, 67) of a secondary control signal adapted to converge the measured force (F) towards a predetermined force setpoint (CF) when the measured force (F) exceeds said force threshold (SF).

2. Robotic system (20) according to claim 1, wherein the main axis (Y) consists of a clamping axis for the elongated flexible medical instrument (5), the first direction being oriented towards the elongated flexible medical instrument (5).

3. Robotic system (20) according to claim 1 or 2, wherein the method (200) includes the following additional steps: - measurement (202) of a position (P) of the drive member (54, 56) along the main axis (Y), and - displacement (230) of the drive member (54, 56) along the main axis (Y) in a second direction opposite to the first direction, with transmission (232) to the actuator (62, 63, 64, 65, 66, 67) of a tertiary control signal adapted to converge the measured position (P) towards a predetermined position setpoint.

4. Robotic system (20) according to claim 3, wherein the method (200) comprises between the first-direction and second-direction movement steps (210, 230) an additional step (220) of immobilizing the drive member (54, 56) along the main axis (Y) during which a quaternary control signal adapted to maintain the measured force (F) substantially equal to the force setpoint (CF) is transmitted to the actuator (62, 63, 64, 65, 66, 67).

5. Robotic system (20) according to claim 4, wherein the method (200) comprises, during the immobilization step (220) of the drive member (54, 56) along the main axis (Y), the displacement (224, 226) of the drive member (54, 56) along at least one axis (X, Z) orthogonal to the main axis (Y).

6. Robotic system (20) according to any one of claims 3 to 5, wherein the first-direction and second-direction movement steps (210, 230) are implemented one after the other, in a cyclically repeated manner.

7. Robotic system (20) according to any one of claims 3 to 6, wherein the measured position (P) is deduced from a current position of the actuator (62, 63, 64, 65, 66, 67).

8. Robotic system (20) according to any one of the preceding claims, wherein the method (200) includes an additional step (202) of measuring a position (P) of the drive member (54, 56) along the principal axis (Y), the speed setpoint (Cv) having a first value (Vi) as long as the measured position (P) is below a predetermined position threshold (SP) and a second value (V2), lower than the first value (Vi), when the measured position (P) is above said position threshold (SP).

9. Robotic system (20) according to claim 8, wherein the position threshold (SP) is such that when the measured position (P) is equal to said position threshold (SP) the drive member (54, 56) is not in contact with the elongated flexible medical instrument (5).

10. Robotic system (20) according to any one of the preceding claims, wherein the force setpoint (CF) is greater than the force threshold (SF).

11. Robotic system (20) according to any one of the preceding claims, wherein the measured travel speed (V) is deduced from a current speed of the actuator (62, 63, 64, 65, 66, 67).

12. Robotic system (20) according to any one of the preceding claims, wherein the measured force (F) is deduced from a current supply power of the actuator (62, 63, 64, 65, 66, 67).

13. Robotic system (20) according to any one of the preceding claims, wherein the elongated flexible medical instrument (5) consists of a catheter or a catheter guide.

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