Actively controlled steerable medical devices with passive bending modes

Abstract

An apparatus, method and system for a steerable medical device configured to be used in conjunction with guide tools and equipment in a robotically controlled medical procedure, the guide tools and equipment including an endoscope, a camera, a cutting tool and a catheter. In one embodiment, the steerable device includes an elongated body (100); a control wire (110) disposed in a channel (104) of the elongated body and displaceable along the channel to bend the elongated body; and a controller (320) for selectively controlling a driving force applied to the control wire (110) in an active control mode and a passive control mode. In the active control mode, the controller actively bends at least a portion of the elongated body. In the passive control mode, the controller (320) reduces the strain or displacement of the control wire so that the control wire becomes compliant with an external force.

Description

[0001] Citation of Related Applications

[0002] This application claims priority to U.S. Provisional Application No. 62 / 855,354, filed May 31, 2019, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure generally relates to robotic medical devices. More specifically, the present disclosure illustrates various embodiments of articulated, steerable medical devices with controllable stiffness that can be applied to guide interventional tools and instruments (such as robotic endoscopes and catheters) through tortuous intraluminal pathways. Background Art

[0004] Flexible medical devices such as endoscopic surgical instruments and catheters are well known and continue to gain acceptance in the medical field. These flexible medical devices typically include an elongated flexible tube, often referred to as a sleeve or sheath, having an opening extending from a proximal end to a distal end. One or more tool channels extend along the sheath (usually inside the sheath) to allow access to an end effector located at the distal end of the sheath. The endoscope may have imaging, illumination, and steering capabilities at the distal end of the flexible shaft, thereby enabling navigation of nonlinear lumens or tortuous paths within the human body. This type of medical device should provide a flexible pathway with at least one or more than one curve to access the intended lesion area while maintaining torsional stiffness and longitudinal stiffness so that the physician can control the end effector located at the distal end by manipulating the proximal end of the instrument.

[0005] In minimally invasive surgery (MIS) or natural orifice transluminal endoscopic surgery (NOTES), in which steerable medical endoscopic tools are primarily used to access difficult-to-reach desired lesion areas, some requirements for medical device design are (1) minimizing the outer size (outer diameter) of the bendable medical device, (2) maximizing the size of the opening (inner diameter) for the tool channel, and (3) providing appropriate flexibility (or stiffness) for traveling in a tortuous path without causing pain or discomfort to the patient. Thus, in order to optimize size, the bendable medical device must preferably include a sheath with a minimum wall thickness; and in order to minimize patient discomfort, the bendable medical device must preferably have a minimum overall outer diameter. At the same time, such a thin and delicate bendable medical device must provide sufficient stiffness and flexibility to be steerable and thus move in multiple directions, including insertion and retraction along its longitudinal axis, rotation about the longitudinal axis (axial rotation), and radial bending in multiple directions and / or multiple segments of the device. Recently, in order to enhance the maneuverability of the steerable medical device along a tortuous path within a lumen, a robotic device capable of controlling stiffness and navigation has emerged. In known robotic instruments, different techniques are disclosed in patents and non-patent publications for local bending and curve generation in the distal portion of a steerable instrument.

[0006] For example, pre-grant patent application publication US 20160067450A1 describes a flexible device with nested catheters, which is provided with multiple catheters to maintain the shape of the proximal portion while driving the distal portion of the tendon-bending bendable medical device. The multiple catheters will be controlled in a binary manner with the proximal end of the catheter constrained or unconstrained. By selecting a constrained catheter, the bendable medical device can change the length of the distal segment bend by changing the stiffness of the bendable medical device based on the area where the catheter is deployed.

[0007] Pre-grant patent application publication US 20100280449A1 discloses a steerable instrument having multiple independent segments, which can decouple the actuation force from multiple parts of the steerable segments to allow the controlled segments to follow the curvature of the path during the insertion of the medical device. US 20100280449A1 discloses a steerable instrument having a "first part" and a "second part", wherein the "first part" is a steerable catheter and the "second part" is a steerable sheath. Each part is independently controlled and can be decoupled from the articulation force or steering force to allow each part to follow the path. The first part can then be actuated again and inserted through the second part around the curvature of the second part. The disclosure focuses on the decoupling of the articulation force or steering force in the selected part while inserting the steerable instrument through the pulmonary airway.

[0008] Pre-grant patent application publication US 20140276594A1 discloses a robotic surgical system in which a steerable instrument is controlled by a control wire. The control wire is actuated by a pulley, and the torque on the pulley is measured by a torque sensor. The torque on the pulley is converted into control wire tension. In this disclosure, only tension can be sensed because the control wire can only be pulled against the pulley (i.e., pushing the control wire against the pulley will cause the control wire to untie from the pulley). U.S. Patent 8,644,988 discloses a steerable medical device that uses force and feedback control to steer the medical device, such as a catheter, with non-negligible compliance (i.e., no slack) between the positioning of the distal joint and the proximal actuator.

[0009] The non-patent publication by Blanc et al., “Flexible Medical Devices: Review of Controllable Stiffness Solutions,” Actuators, June 23, 2017, doi:10.3390 / act6030023, and the paper by Loeve et al., “Scopes Too Flexible…and Too Stiff,” IEEE Pulse, January 2011, DOI:10.1109 / MPUL.2010.939176, both describe many design challenges and proposed solutions for providing steerable medical devices with controllable flexibility and / or stiffness.

[0010] However, the prior art in general, and the exemplary publications discussed above in particular, do not address certain situations in a typical workflow or process where a steerable instrument is desired to have a certain level of flexibility as needed. More specifically, the known prior publications do not disclose a steerable instrument having an actively controlled passive bending mode with zero tension on the control wire, which may be desirable in certain situations. Summary of the invention

[0011] According to at least one embodiment of the present disclosure, a steerable medical device with an active control passive bending mode is provided. According to one aspect of the present disclosure, the steerable medical device comprises: a slender body, the slender body having a longitudinal axis, a proximal end, a distal end and a plurality of channels arranged along the slender body, the slender body having an inflexible segment and at least one bendable segment; a control line, the control line is arranged in the channel of the slender body and extends through the inflexible segment and the at least one bendable segment, the control line is fixed at the distal end of the at least one bendable segment and is configured to slide along the channel so as to bend the slender body at an angle relative to the longitudinal axis; a drive unit operably connected to the control line at the proximal end of the control line; a sensor, the sensor is configured to output a signal indicating the amount of strain applied to the control line or the amount of distance displacement of the control line; and a controller, the controller is configured to enable the drive unit to selectively apply a driving force to the control line in one of an active control mode and a passive control mode. In the active control mode, the controller uses the command signal to cause the drive unit to apply a driving force to bend the elongated body to navigate through a tortuous path. In the passive control mode, the controller uses the signal output from the sensor to cause the drive unit to reduce the amount of strain applied to the control line or reduce the distance displacement of the control line.

[0012] According to another aspect of the present invention, a steerable medical device comprises: an elongated body (100), the elongated body (100) having an inflexible segment (102) and at least one bendable segment (103), and comprising a plurality of channels (104, 105) extending from a proximal end to a distal end of the elongated body (100) along a longitudinal axis (Ax); a control wire (110), the control wire (110) being arranged in a first channel (104) of the elongated body (102), extending through the inflexible segment and the at least one bendable segment, and being attached to the at least one bendable segment. segment; a sensor (221, 231), the sensor (221, 231) is configured to measure the strain or displacement of the control line (110); an actuator (310), the actuator (310) is mechanically coupled to the control line (110), and is configured to actuate at least one bendable segment (103) of the slender body (100) by applying a driving force to the control line; and a controller (320), the controller (320) is configured to control the action of the actuator (310) according to an active control mode and a passive control mode based on an external force other than the driving force applied to the control line.

[0013] In accordance with various aspects of the present disclosure, steerable medical devices are significantly improved by providing an actively controlled passive bending mode whereby (1) the force on the control wire is zero when maximum flexibility is required in the steerable instrument; (2) the force and displacement of the control wire can be continuously monitored regardless of the control mode employed; (3) friction in the steerable instrument is minimized even when traveling through tortuous paths; and (4) the proximal end of the control wire can translate freely while being connected to its corresponding actuator.

[0014] These and other objects, features and advantages of the present disclosure will become apparent when the following detailed description of exemplary embodiments of the present disclosure is read in conjunction with the accompanying drawings and the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Other objects, features and advantages of the present disclosure will become apparent from the following detailed description when taken in conjunction with the accompanying drawings which show exemplary embodiments of the present disclosure.

[0016] Figure 1A An exemplary embodiment of a continuum robotic system 1000 suitable for catheter or endoscope-assisted minimally invasive surgery (MIS) using actively controlled passive bending modes is illustrated. Figure 1B Illustrated in greater detail is a steerable instrument 100 having an elongated flexible shaft (elongated body) and a plurality of channels or openings extending from a proximal end to a distal end thereof.

[0017] Figure 2A is a perspective view of an exemplary steerable instrument 100 having two curved sections. Figure 2B A perspective view showing a representative guide member having a through hole (guide hole) for guiding a control wire. Figure 2C An example of bending or steering a single bending section 106 of the steerable instrument 100 is shown.

[0018] Figure 3 An exemplary embodiment of actively controlling a passive bending mode, referred to herein as a "force control loop" implementation, is illustrated.

[0019] Figure 4 An exemplary embodiment of an actively controlled passive bending mode of the steerable instrument 100 is illustrated, which is referred to herein as a "frictionless direct drive" implementation.

[0020] Figure 5A and Figure 5B An exemplary embodiment of a frictionless direct drive configuration implemented by an induction motor having a frictionless bearing is illustrated.

[0021] Fig. 6A , Figure 6B and Figure 6CAnother exemplary implementation of a frictionless direct drive configuration implemented by an ultrasonic motor is illustrated.

[0022] Fig. 7A An exemplary block diagram of a control system 1500 configured to implement an actively controlled passive bending mode of a steerable medical device 100 in accordance with the present disclosure is illustrated. Figure 7B The diagram illustrates functional blocks of a computer 1600 that may operate a motor controller 1504 of the control system 1500 or be a part of the motor controller 1504 .

[0023] Figure 8 An exemplary flow chart for implementing an actively controlled passive bending mode of the steerable medical device 100 with a feedback force control loop is illustrated.

[0024] Fig. 9 An exemplary flow chart for achieving an actively controlled passive bending mode of the steerable medical device 100 with frictionless direct drive is illustrated.

[0025] Fig. 10A The diagram illustrates an exemplary flow chart implementing an algorithm that causes a drive unit to reduce the amount of strain or compression applied to a control wire, or reduce the amount of distance displacement of the control wire, so that when maximum flexibility is required in a steerable instrument, the control wire complies with external forces by reducing the force in the control wire to zero. Fig. 10B An exemplary process is illustrated for operating a scenario of user activated controls of the steerable instrument 100 in an active control mode and a passive control mode. DETAILED DESCRIPTION

[0026] The embodiments disclosed herein are described in detail with reference to the accompanying drawings. Although the drawings represent some possible configurations and methods, the drawings are not necessarily drawn to scale, and certain features may be enlarged, removed, or partially segmented to better illustrate and explain certain aspects of the present disclosure. The descriptions recorded herein are not exhaustive and are not intended to define or limit the claims to the precise forms and configurations shown in the drawings and disclosed in the following detailed description.

[0027] In all drawings, unless otherwise indicated, the same reference numerals and characters are used to represent the same features, elements, components or parts of the illustrated embodiments. In addition, although the present disclosure will now be described in detail with reference to the drawings, it is done in conjunction with the exemplary embodiments. It is intended that various changes and modifications may be made to the illustrated exemplary embodiments without departing from the true scope and spirit of the present disclosure as defined by the appended claims.

[0028] When a feature or element is referred to as "on" another feature or element in this article, it can be directly on another feature or element, or there can also be intervening features and / or elements. On the contrary, when a feature or element is referred to as "directly on" another feature or element, there are no intervening features or elements. It should also be understood that when a feature or element is referred to as "connected", "attached", "coupled", etc. to another feature or element, it can be directly connected, attached or coupled to another feature or element, or there can be intervening features or elements. On the contrary, when a feature or element is referred to as "directly connected", "directly attached" or "directly coupled" to another feature or element, there are no intervening features or elements. Although described or represented with respect to one embodiment, the features and elements so described or represented in one embodiment can be applied to other embodiments. It will also be appreciated by those skilled in the art that references to structures or features arranged "adjacent" to another feature can have portions overlapping or below adjacent features.

[0029] The present disclosure relates generally to medical devices and illustrates various embodiments of articulated steerable medical devices that can apply controllable stiffness to guided interventional tools and instruments (such as endoscopes and catheters) through tortuous paths within a lumen. Embodiments of the present disclosure can be configured as part of a robotic system, although those skilled in the art will appreciate that the steerable instruments disclosed herein can also be used in similar applications that do not require a robotic system.

[0030] Embodiments of steerable medical devices and their various parts are described using their states in three-dimensional space. As used herein, the term "position" refers to the location of an object or a portion of an object in three-dimensional space (e.g., three translational degrees of freedom along Cartesian X, Y, Z coordinates); the term "orientation" refers to the rotational placement of an object or a portion of an object (three rotational degrees of freedom - e.g., roll, pitch, and yaw); the term "pose" refers to the position of an object or a portion of an object in at least one translational degree of freedom, and the orientation of the object or a portion of an object in at least one rotational degree of freedom (up to a total of six degrees of freedom); the term "shape" refers to a set of poses, positions, and / or orientations measured along the elongated body of an object.

[0031] As is known in the medical device art, the terms "proximal" and "distal" are used herein with respect to manipulation of the end of an instrument extending from a user to a surgical or diagnostic site. In this regard, the term "proximal" refers to the portion of the instrument that is closer to the user, while the term "distal" refers to the portion of the instrument that is farther from the user and closer to the surgical or diagnostic site.

[0032] <Configuration of divertible medical equipment>

[0033] Figure 1A The diagram illustrates the general structure of a continuum robot system 1000 according to one embodiment of the present disclosure, which includes a computer system 400 (e.g., a console), a robot control system 300, and a steerable instrument 100, which is connected to the control system 300 via a handle interface 200. The steerable instrument 100 has a proximal non-steerable segment 102 and a steerable segment 103 composed of a plurality of curved segments suitable for minimally invasive medical procedures assisted by a catheter or endoscope. Specifically, Figure 1A A robotically controlled steerable instrument 100 is shown having a steerable segment 103 divided into a plurality of curved sections or segments (1, 2, 3...n) arranged along a longitudinal axis Ax and configured to bend at least one of the steerable segments at an angle β relative to the longitudinal axis Ax.

[0034] The steerable instrument 100 is controlled by an actuation system consisting of a handle interface 200 and a control system 300. The control system 300 typically includes a controller, or is connected to a computer system 400, and appropriate software, firmware, and peripheral hardware operated by a processor or central processing unit (CPU) 410, which will be described later. Among other functions, the control system 300 and the computer system 400 can provide an image display 420 and a graphical user interface (GUI) 422 to the surgeon or other operator to interact and operate the steerable instrument 100. The handle interface 200 provides an electromechanical interconnection between the steerable instrument 100 and the control system 300. For example, the handle interface 200 can provide mechanical, electrical, and / or optical connections, as well as a data / digital acquisition (DAQ) system for interfacing the steerable instrument 100 and the control system 300. The handle interface 200 may also provide an access port 250 for inserting a medical tool, one or more mechanical dials or knobs 252 that an operator may use to manually control operation of the end effector and / or steering of the instrument, and a user interface 254 having one or more control buttons and status indicators.

[0035] As part of the user interface 254, the handle 200 may include an LED for providing the user with the operating status of the robotic steerable instrument 100. In an embodiment, the LED may include, for example, different light colors to indicate normal operation (green light) and abnormal operation (red light), respectively. Alternatively, the LED may include, for example, a flashing code to indicate the type of abnormal operation. In addition, the user interface 254 may include an emergency on / off switch to manually stop the actuation of the steerable instrument in an emergency.

[0036] Figure 1BThe steerable instrument 100 is illustrated in more detail and has an elongated flexible shaft (elongated body) generally referred to as a sleeve or sheath; the sheet is formed of a non-steerable segment 102 and a steerable segment 103 composed of a plurality of curved segments; one or more channels or openings extend from the proximal end to the distal end along the longitudinal axis Ax of the steerable instrument 100. Among the openings or channels, the sheath may include one or more tool channels 105 extending along the wall (usually on the interior) of the sheath, and a plurality of guidewires 104 extending along the wall (usually on the interior) of the sheath. The one or more tool channels 105 allow access to an end effector to be delivered or located at the distal end of the steerable segment 103. The one or more channels 105 may also be used to deliver or retrieve liquid or gaseous substances (e.g., air, water) to or from a target area, or for passing optical fibers and / or electrical wires. In addition, the one or more channels 105 may be used to insert a medical imaging device 180, such as an endoscopic camera or an optical fiber-based imaging probe. Examples of endoscopic cameras include, but are not limited to, chip-on-tip (COT) cameras, such as cameras having a miniature CMOS sensor disposed at the tip of the imaging device. Examples of fiber-based imaging probes include, but are not limited to, near-infrared autofluorescence (NIRAF) imaging probes, spectrally encoded endoscopy (SEE) probes, intravascular ultrasound (IVUS) probes, or optical coherence tomography (OCT) imaging probes.

[0037] The wire conduit 104 allows the anchoring and / or passage of a control line 110 for steering (or bending) at least one segment of the sheath. To this end, at the distal end of the sheath, the steerable segment 103 is composed of a plurality of bendable segments. At the proximal end of the sheath, the non-steerable segment 102 is connected to a handle or handle interface 200, which has one or more control wheels or knobs 252 for bending the steerable segment in one or more directions. An access port 250 for tools to enter the tool channel 105 is also included in the handle or handle. The access port 250 can be used to insert small instruments, such as small forceps, needles or electrocautery instruments, etc. In some embodiments, the wire conduit 104 can be used to pass the wire 111 to, for example, connect an electromagnetic (EM) sensor 115 to an electrical terminal 212 located at the interface handle 200.

[0038] The steerable instrument 100 is configured to provide one or more curved curves for a flexible passage to a target area within the lumen to reach the desired target area near the distal end of the instrument while maintaining torsional stiffness and longitudinal stiffness, so that the physician can control the end effector or imaging device located at the distal end of the sheath by manipulating the control system. In order to provide this steerable function, the steerable instrument 100 is controlled by a plurality of control wires 110 arranged in a guide wire tube 104 along the wall (usually inside) of the sheath. Some control wires 110 are anchored at the distal end of the sheath using a wire anchor 112, and other control wires 110 can be anchored at a distance from the distal end using a wire anchor 113. In an exemplary embodiment, a steerable instrument 100 having 6 control wires can have two pairs of control wires 110 (i.e., 4 control wires) anchored in the middle of the sheath (e.g., at one or more turning points 107) using a wire anchor 113, and another pair of control wires 110 (2 control wires) can be anchored at the distal end of the sheath by a wire anchor 112. In this manner, the steerable instrument 100 may have at least two (ie, two or more) steerable sections controlled by three pairs of antagonistic control wires 110 that pass through separate guidewires 104 , respectively.

[0039] At the proximal end of the instrument 100, the handle interface 200 is configured to provide a mechanical connection and an electromechanical interface between the steerable instrument 100 and the control system 300. In one embodiment, the handle interface 200 provides a plurality of electromechanical connections 210 (one connection for each control wire 110) so that the actuator system 310 can mechanically operate each control wire 310. The controller 320 is used to electronically control the operation of each control wire 110 based on the tension or torsion state of each control wire, as described in further detail later in this disclosure.

[0040] like Figure 1B As shown in FIG. 3 , the control system 300 may include a plurality of actuation motors (or actuators) 1-M as part of an actuator system 310, where M is an integer greater than zero and equal to the number of control wires 110. In this manner, each control wire 110 may be actively controlled via a feedback control loop 325 to achieve appropriate shaft guidance for navigation through the patient's anatomy.

[0041] Figure 2A1 is a perspective view of an exemplary steerable instrument 100. According to one embodiment, the steerable instrument 100 may be a wire-driven continuum robot including a proximal non-steerable segment 102 and a steerable segment 103, the steerable segment 103 being divided into a plurality of curved segments or segments 106a and 106b having at least one turning point 107. In the steerable instrument 100, a plurality of control wires 110 pass through a guide tube 104 along the wall of the non-steerable segment 102 of the sheath, and through a plurality of guide members 108a, 108b in the steerable segment 103 of the sheath, as well as anchor members 103a, 103b, extending from the proximal end to the distal end. The control wires 110 are arranged in a direction parallel to the Z axis; some of the control wires 110 are coupled to the first anchor member 103a at the turning point 107, and some of the control wires 110 are coupled to the second anchor member 103b at the distal end. All control lines 110 are coupled at their proximal ends to individual motors or actuators (actuator systems 310, such as Figure 1B ). The control wire 110 may be a metal wire, such as a piano wire, a stainless steel wire, or a nickel-titanium alloy wire. The anchoring members 103a and 103b have a ring shape whose central axis extends along the Z-axis direction. Among the plurality of control wires 110, some control wires are fixedly attached to the anchoring member 103a, and some control wires are attached to the anchoring member 103b, for example, by bonding, pinning, ultrasonic welding or thermal welding, press fitting, or screws.

[0042] The support segment or non-steerable segment 102 of the sheath has a cylindrical shape with its longitudinal axis extending in the Z-axis direction, and a plurality of conduits or through holes extending in the wall of the cylindrical shape. The support segment is a non-steerable segment and has the function of transmitting the actuation force from the actuator when the control wire passing through the through hole of the sheath is driven in the Z-axis direction without any buckling or slack of the control wire.

[0043] Figure 2BA perspective view of a representative guide member 108b and a representative guide member 108a is shown. Each guide member has an annular shape with a central axis or longitudinal axis Ax extending in the z-axis direction. The guide member 108b has a wire tube or guide hole 104a, 104b and 104c extending along the wall of the annular shape of the guide member. The guide holes 104a, 104b and 104c are configured to allow corresponding control wires 110 to pass through and slide through during the navigation (steering) operation of the steerable device 100. Among the control wires 110, one control wire can be fixedly attached to a given anchoring member in the inner surface of the guide hole of a given anchoring member, and the other two control wires can slide relative to the guide hole of a given anchoring member. Since each guide member 108b contacts the control wire 110 through the guide hole 104, the guide member may include a lubricating material with a low coefficient of friction. The guide member 108a has guide holes 104a, 104b, 104c, 104d, 104e and 104f, allowing the control wire 110 to pass through the curved segment 106a and the curved segment 106b. Similar in design to the curved segment 106b, the curved segment 106a has a plurality of guide members 108a, each of which has guide holes 104a to 104f. The guide holes 104a to 104f are arranged to allow the control wire 110 coupled to the anchor member 103b and the control wire coupled to the anchor member 103a to pass through the guide holes.

[0044] Next, the bending motion (steering) of the steerable instrument 100 when the control line 110 is actively driven to navigate through a curved path is described. For simplicity, the bending of a single curved segment or section is explained. Figure 2C As shown in FIG. 1 , a single curved segment 106 of a steerable instrument 100 includes, from its distal end, an anchoring member 109, a plurality of guide members 108, and a supporting non-steerable segment 102 having a plurality of guide holes. Control wires 110a, 110b, and 110c extend from the proximal end of the steerable instrument to the distal end along guide holes 104a, 104b, and 104c, respectively. One or all of the control wires 110 are fixedly coupled to the anchoring member 109 at their distal ends. The control wires 110 coupled to the anchoring member 109 at their distal ends are controlled by the action of an actuator or motor connected to the proximal end of each control wire (see FIG. 1 ). Figure 1A-1B ) can slide relative to the guide member 108. One of the three control wires 110 (e.g., Figure 2C The control wire 110b in the embodiment is fixed relative to all guide members 108 (or mechanically grounded), and the remaining two control wires 110 (e.g., Figure 2C The control lines 110a and 110c) in the guide member 108 can slide relative to the guide hole.

[0045] When bending the steerable instrument 100, each control wire 110 is individually controlled by a corresponding actuator or motor. Figure 2C In the embodiment of the present invention, the control wire 110a is pulled with a first control force F1 and the control wire 110c is pulled with a second control force F2 different from the force F1 (in this example, the control force F2 is less than the control force F1) while the control wire 110b can be fixed or anchored to the anchor member 109. In this way, the bending segment 106 can be bent in a desired direction according to the combination of the driving amounts of the linear displacements of the control wires 110a and 110c. In order to control the posture of the distal end of the steerable instrument 100, it is sufficient to drive two (or even one) of the three control wires. When the forces F1 and F2 are applied to the control wires 110a and 110c, respectively, the corresponding sensors detect the tensile forces applied thereto, as described in more detail below. Here, it should be noted that the forces F1 and F2 are not limited to tensile forces applied by pulling the control wires. The forces F1 and F2 can also be compressive forces applied to the control wire 110 by mechanically pushing the control wire with a desired amount of compressive force.

[0046] Although the above Figure 2C The case of driving a control wire anchored at the distal end of a single curved segment 106 is described, but if the driving Figure 2A The control wires of all bending segments can independently and selectively control the posture of each bending segment (1, 2, 3...N) so that it bends in a serpentine motion, depending on the amount of drive of each control wire by the actuator of the actuator system 310 (drive unit). In addition, a mechanism for twisting or rotating the longitudinal axis of the steerable instrument 100 by winding a wire can be set up. In order to provide a certain amount of rotation or torsional action to the steerable instrument 100, the bending segment can be bent in the desired direction by first driving only one control wire 110, and then the entire sheath can be rotated by actuating the second control wire 110 in a different bending segment. This manipulation of the steerable instrument 100 can be achieved based on well-known mechanical and kinematic principles, such as those described in U.S. Patent No. 9,144,370, which is incorporated herein by reference.

[0047] According to one embodiment, Figure 2A-2C The steerable instrument 100 shown in the drawings may have an outer diameter of approximately 0.14 inches, a length of the distal steerable section of approximately 2.0 inches, and an overall length of the instrument 100 of approximately 24 inches. Similar to the guide ring, the anchoring member has a guide tube 104 and a tool channel 105, and is typically constructed of medical grade plastic or similar composite materials. These materials allow for the preparation of flexible but torsionally resilient steerable instruments, such as catheters and endoscopes of reduced size. For example, other prototype dimensions for the steerable instrument 100 are an outer diameter (OD) of approximately 3.3 mm, an inner diameter (tool channel) of approximately 2.4 mm, and a length of approximately 550 mm.

[0048] Typically, during the insertion or retraction of a steerable instrument, the centerline of the lumen (e.g., airway) is the desired trajectory to be followed during the active control of the curved segment. For this reason, known steerable instruments, such as robot-guided catheters or endoscopes, attempt to implement various concepts of shaft guidance systems, with the goal of forcing the flexible shaft to follow the desired trajectory. In one example, when using the shaft guidance system, the steerable instrument is advanced through the lumen, while a sensor measures the insertion depth of the shaft guide and the angle of the steerable tip segment controlled by the user to obtain trajectory information. The trajectory information is stored in the memory of the system and is continuously updated. After a brief advancement of the insertion depth, the shape of the steerable shaft guide is corrected by adjusting (rotating or bending) the segment of the instrument in a manner that the new shape closely matches the desired trajectory. Repeat the process until the target area is reached. When the steerable instrument is withdrawn from the patient, the same process is applied. For example, see US 2007 / 0135803, which is included herein by reference for all purposes.

[0049] However, most steerable medical devices still rely on support from the surrounding anatomical structures to follow the desired trajectory during insertion or withdrawal. In particular, when external disturbances (e.g., external forces generated by involuntary movements of the patient) are applied to the steerable instrument, it is difficult to keep the steerable instrument on the desired insertion (or withdrawal) trajectory because the tip (or other part) of the steerable instrument can get stuck on the patient's anatomical structure, thereby hindering proper navigation (e.g., due to unexpected bending or kinking of the instrument). It is worth noting that during the withdrawal of the steerable instrument, the guidance system is generally kept inactive, which puts the steerable instrument in an uncontrolled (passive) state. However, the steerable instrument can still contact the patient's anatomical structure and get stuck accidentally; this can cause discomfort and / or pain to the patient. To avoid this situation, the patent application publication US 2007 / 0135803 cited above proposes actively controlling the shape of the steerable instrument by using a sensor-based mapping technology that is continuously maintained while the instrument is moved within the patient's body.

[0050] However, when removing a steerable instrument from a path through a patient's anatomy, it would be beneficial to make the instrument very flexible (e.g., zero stretch) while still maintaining the ability to actively control its stiffness at any given time. For example, making the instrument very flexible (compliant) during removal can reduce trauma to the patient's anatomy (e.g., airway, colon wall, etc.), reduce the force required to remove the instrument, and reduce patient discomfort. However, if the instrument needs to be reinserted or reoriented after partial or complete removal (e.g., due to patient breathing or movement), immediate control of the instrument's position and stretching force is required. Thus, there is a need for an improved steerable medical device having (1) a minimal outer dimension (outer diameter), (2) a maximum opening dimension (inner diameter) for a tool channel, and (3) actively controlled flexibility (or stiffness) to effectively navigate through a tortuous path without causing any pain or discomfort to the patient. In particular, if the device needs to be reinserted or reoriented after partial or complete removal (e.g., due to patient breathing or movement), it is desirable to make the device very flexible (e.g., with approximately zero stretch) while still maintaining the ability to control its stiffness in an actively controlled passive bending mode.

[0051] In the present disclosure, a control guide system is used to place the steerable instrument 100 in a passive control state (active control passive bending mode) such that (1) the force on the control wire 110 is zero when maximum flexibility is required in the steerable instrument; (2) the force and displacement of the control wire 110 are continuously monitored regardless of the control mode used; (3) friction in the steerable instrument is minimized even when traveling through a tortuous path during insertion or withdrawal; and (4) the proximal end of the control wire 110 can translate freely while still being actively connected to the corresponding actuator.

[0052] More specifically, the present disclosure proposes a passive bending mode that can be easily converted to active shape control and vice versa without losing any critical feedback information, such as control line position and control line tension or compression force. The main principle of this passive-active mode conversion is that the actively controlled drive line (control line 110) allows negligible force to be applied, thus producing a very soft bending behavior of the steerable instrument 100. This effect or mode is referred to as the active control passive bending mode of the steerable medical device in this article. Although the active control passive bending mode of the steerable medical device can be achieved in various configurations, it is important that the drive line is directly driven with hardware that avoids increasing friction or generating excessive relaxation. To this end, it is preferred to drive the control line 110 with hardware that can maintain a stable and precise relationship between the controller and the end effector, thereby accurately controlling the position of the actuated element. The active control passive bending mode is particularly advantageous in controlling the smooth and precise bending of the steerable medical device during insertion and withdrawal through the tortuous path of the patient's anatomy.

[0053] In any embodiment, there is a motor or actuator that actuates the control wires. Each control wire can have a separate motor or actuator, or there can be a single motor or actuator that can control each control wire individually. The control wire moves longitudinally along the length of the instrument with the other control wires to generate a bending moment at a distal position on the instrument. The structure of the instrument allows one or more of these bending segments to be actuated individually. In the present disclosure, it is important that regardless of the type of actuator used (DC motor, linear induction motor, ultrasonic motor, etc.), a linear force is generated to move the control wires individually in an active bending mode, and a control loop is used to keep each control wire completely passive (compliant and able to be moved by external forces, just like the control wire is disconnected from any drive actuator), while still maintaining encoder position feedback and force feedback on the drive wire. In one embodiment, in order to keep each control wire completely passive, the controller achieves force balance by reducing the strain force to essentially zero. In another embodiment, the controller implements active movement of the actuator connected to the control wire; this is different from force balance feedback because in this case, the actuator can be passively moved by the control wire.

[0054] In the case of a direct current (DC) motor, a conversion from rotary motion to linear motion is required; for this purpose, a lead screw or ball screw mechanism is usually used. However, other alternatives such as ultrasonic and direct drive actuators may be more advantageous. The benefit of ultrasonic motors and linear induction motors is that they are both linear actuators and do not require mechanical conversion. Ultrasonic motors or linear induction motors can drive the control line directly without the need for any mechanical gears or intermediate mechanisms. One benefit of using such a linear actuator to directly drive the control line is the reduction of friction and other nonlinearities (for example, mechanical ramps in a lead screw mechanism).

[0055] In active control mode, each control wire for a given bending segment is assigned a specific position. Any error in position is measured and corrective action is taken to reduce that error. This process occurs many times per second and will quickly reduce position errors to negligible amounts. The result is closed-loop control of the desired shape of the instrument based on the positions of the control wires.

[0056] However, it is sometimes necessary to conform the shape of the instrument to external forces applied to the instrument, such as forces from the walls of a tortuous path, or unexpected changes in the navigation path due to, for example, the patient's respiratory movement. In order to apply force feedback, the present disclosure includes a force sensor on each control wire. When stretch or compression is sensed on the control wire, the controller can measure the stretch or compression or control wire displacement based on the signal from the sensor. An algorithm is then provided to take corrective action to reduce the measured force toward zero; this will reduce the total force acting between the tortuous path walls and the instrument. This process also occurs many times per second and can quickly reduce the force to a negligible amount.

[0057] In the present disclosure, another aspect of reducing the external forces applied to the instrument due to contact between the instrument and the tortuous path is achieved through a unique control wire configuration and actuation method. Most known steerable instruments use only tension mode in their control wires and have at least two control wires in an antagonistic configuration for each set of actuation positions. This means that when only tension is used, a bending segment that can bend in one plane will require two control wires. This conventional method also requires a rigid backbone in the instrument to prevent the instrument from deforming in the longitudinal direction under tension. However, in the present disclosure, both tension and compression can be used in the control wires, and the steerable instrument has no backbone. In contrast, in the present disclosure, multiple control wires are used in a symmetrical configuration to generate pure bending moments in the bending segments using force couples. Pure bending moments generate zero longitudinal forces along the instrument; this not only allows precise control of tension and compression forces, but also allows the size of the instrument to be reduced by not including a backbone. Typically, for control wires that only have tension, a small but non-zero amount of tension is always maintained on the control wire to preload the mechanism and avoid any slack or nonlinearity that would destroy the control system. The steerable instrument of the present disclosure does not have this problem. There is no mechanical tilt or slack in the control line; especially when it is directly connected to the actuator; and the actuator is a linear actuator. This allows all axial forces in the control line to be reduced to zero while continuously monitoring and adjusting the control force. This action coupled with the lack of a rigid backbone produces a very compliant instrument on demand. In addition, the programming algorithm changes seamlessly from active control bending mode to passive control bending mode and vice versa.

[0058] <First implementation: force control loop>

[0059] Figure 3 An exemplary embodiment of actively controlling a passive bending mode, referred to herein as a "force control loop" implementation, is illustrated. Figure 3 As shown in FIG, each control line 110 of the steerable instrument 100 is connected at its proximal end to a corresponding motor and motor control system. For ease of illustration, Figure 3A first control line 110a is shown connected to a first linear motor 311, which is in turn controlled by a first motor control system 321 (motor controller). Similarly, a second control line 110b is connected to a second linear motor 312, which is in turn controlled by a second motor control system 322. To ensure precise positioning (to avoid looseness), the linear motor 311 is fixed to a structural base 311a and the linear motor 312 is fixed to a similar base 312a. The base 311a / 312a can be, for example, a housing or chassis of a patient interface unit (PIU) that surrounds at least a portion of the interface 200 and the control system 300. For a steerable instrument 100 having i to M control lines 110, a corresponding number of i to M control motors or actuators is expected. However, it is neither expected nor required to provide a corresponding equal number of motor controllers. As long as each motor M is individually controlled to actuate the corresponding control line 110, a single controller can be programmed to drive each of all motors or actuators described herein separately.

[0060] exist Figure 3 In the embodiment of FIG. 1 , in order to realize the principle of passive-active mode conversion, each control line 110 is also connected to a strain sensor and a position sensor. Figure 3 In the embodiment, the first control line 110a is connected to the strain sensor 221 and the position sensor 231 (displacement sensor). Similarly, the second control line 110b is connected to the strain sensor 222 and the position sensor 232. The strain sensor can be a strain gauge-based, optical-based or encoder-based sensor, while the position sensor can be an encoder-based, electromagnetic-based or Hall effect-based sensor; encoder-based sensors include optical encoders, magnetic encoders, potentiometers, etc.

[0061] The strain sensor detects and / or measures the compressive or tensile force F applied to the driven control wire 110, and outputs a signal (Fi) corresponding to (indicating) the amount of compressive or tensile force (strain) applied to the control wire at any given point in time. Similarly, the position sensor detects the longitudinal position (or distance moved) of the control wire 110, and outputs a signal (Xi) corresponding to (indicating) the current position of the control wire. The signals from the strain sensor and position sensor for each control wire 110 are fed into the motor control system. The motor control system generates a control signal (Ci), which is fed back to the motor or actuator to move the corresponding control wire 110 in the direction of the smaller force. That is, the control signal (Ci) generated by the motor control system is used in the feedback loop of the corresponding actuator or motor, which moves the corresponding control wire 110 in the direction opposite to the direction of force F in order to reduce the amount of strain applied to the control wire. This will result in the residual force in the control wire being negligible after a short amount of time t, as described below with respect to Figures 7A-10B In this manner, the actively controlled slave control wire 110 allows the forces exerted on the steerable instrument 100 to be substantially negligible, thereby producing a very soft bending behavior of the distal end of the instrument.

[0062] <Second implementation: Frictionless direct drive>

[0063] Figure 4 Another exemplary embodiment of an actively controlled passive bending mode of a steerable instrument 100 is illustrated; this embodiment is referred to herein as a "frictionless direct drive" implementation. Figure 4 In the embodiment, the first control wire 110a of the steerable instrument 100 is directly connected to the corresponding first motor 311 via a moving carriage 341 at its proximal end, and the second control wire 110b is directly connected to the second motor 312 at its proximal end via a moving carriage 342. The moving carriages 341 and 342 are mechanically connected to the corresponding motors 311 and 312, for example, by a helical linear shaft configured to linearly displace the control wire 110 along the paths L1 and L2. These helical linear actuators can be based on the well-known lead screw, ball screw or roller screw principles. Both the first and second control motors 311 and 312 are operably connected to the motor controller 320. In addition, the first support wire 121a is connected to the first strain sensor 211 at its proximal end, and the second support wire 121b is connected to the second strain sensor 222 at its proximal end. Each strain sensor outputs a signal corresponding to the amount of strain applied to its nearest control wire 110 (or a signal corresponding to the average of the strain forces applied to at least two nearest control wires 110). The first strain sensor 221 outputs a first strain signal (F i ), the second strain sensor 222 outputs a second strain signal (F i+1). Output signals corresponding to the strain amounts detected by all strain sensors are fed back to the controller 320 as a feedback loop 325. In some embodiments, the controller 320 can be implemented using a standard scheme such as proportional integral derivative control (PID).

[0064] exist Figure 3 In the above-mentioned embodiment, the linear motor is connected to the control line 110, and the strain sensor is arranged between them. Figure 4 In an embodiment, the linear motor 311 / 312 is directly connected from the moving carriage 341 / 342 to the corresponding control line 110a / 110b. In order to monitor the strain applied to the control line, a first strain sensor is set at the distal end of the first support line 121a, and a second strain sensor 222 is set at the proximal end of the second support line 121b. Through this direct connection configuration, friction is minimized between the moving carriage 341 / 342 and the base (or housing) of the actuator or motor 311 / 312. In this way, when the mode of commanding the linear motor has a zero force - the force from the drive line will displace the moving carriage 341 / 341 of the corresponding motor, thereby eliminating residual force or stretch in the control line.

[0065] Frictionless direct drive using induction linear motors and air bearing stages

[0066] Another implementation of a frictionless direct drive configuration is to use a linear inductive actuator with extremely low friction between the moving carriage and the base of the actuator or motor. An example of this implementation is the use of a precision linear motor with an air bearing. Precision linear motors (PLMs) with air bearings are widely used in optical lithography manufacturing of wafers to achieve almost zero friction and achieve sub-micron position accuracy of table motion. The mover of the PLM floats on the stator through three air bearings in the normal direction and two air bearings in the lateral direction (one on each side). The PLM with air bearings is expected to move in a straight line and can achieve sub-micron positioning accuracy during operation. The advantages of air bearings are almost frictionless, low heat generation and low noise. The PLM with air bearings also greatly reduces the nonlinearity and interference caused by backlash and friction. These advantages make the PLM with air bearings applicable to advanced manufacturing fields, such as semiconductor manufacturing, but can also be implemented in the frictionless direct drive configuration of the control line 110 of the new steerable medical device 100 using a micro-electromechanical system to operate the control line.

[0067] Figure 5A and Figure 5B An exemplary embodiment of a frictionless direct drive configuration implemented by an induction motor having a frictionless bearing is illustrated. Figure 5A In the embodiment, the steerable medical device 100 is similar to the previously described medical device 100. Figure 1A ,1B , 3 and / or 4. Figure 5A In the embodiment, the actuator or motor is implemented as a drive unit 1300 consisting of a mover or motor carriage 1330 and a stator, wherein the stator consists of a magnetic bottom plate 1360 and a top plate or guide plate 1310. The drive unit 1300 is marked as M1, which represents Figure 1A of the motor 1. It is understood that Figure 5A There are multiple drive units 1300 (eg, one for each control line). Figure 5B A diagram showing an induction linear motor (drive unit 1300) in combination with an air bearing stage is shown in more detail. Figure 5B , the top plate or guide plate 1310 includes a plurality of pressure zones (P) 1312 and a plurality of vacuum zones (V) 1314. These zones are balanced to maintain the guide plate 1310 at a predetermined distance from the motor carriage 1330. The pressure zones and vacuum zones are preloaded by the manufacturer and are represented here as springs to illustrate the "floating" effect of the air bearing portion 1320. When the inductive force 1340 applied to the motor carriage 1330 is zero (no inductive force), the mover or motor carriage 1330 can move freely in a linear direction 1302. The position sensor 1331 monitors the linear motion of the motor carriage 1330 and outputs a signal Xi indicating the displacement of the motor carriage 1330 (moving carriage). Here, the signal Xi is used as a feedback signal 1325 to control the actuation of the motor 1300 to the control line 110. The inductive force 1340 is applied to the motor winding 1332 of the motor carriage 1330. An air gap 1350 is provided between the motor winding 1332 and the permanent magnets (N, S) of the magnetic base plate 1360 which is a permanent magnet.

[0068] In this arrangement, the motor carriage 1330 is free floating on the air bearing due to the air gap 1350. There is no friction in the longitudinal direction due to the air gap. And when no current is passed through the linear induction motor, no force is applied to the motor carriage 1330. Then, the motion and force applied to the motor carriage by the control wire 110 will cause the motor carriage to move freely in the linear direction 1302. The motion of the carriage can be continuously measured by the position sensor 1331. When it is necessary to actively control the position of the control wire 110 and the motor carriage 1330, the control system only needs to pass current through the linear induction motor and use the position data as feedback in the control loop, as in the previous embodiment.

[0069] Figure 5BA simple diagram of a linear induction motor 1300 paired with a frictionless air bearing is illustrated. Both elements, bearings and an inductive drive force, are necessary to implement this embodiment. Here, there must be a mode in which the motor carriage 1330 (which is attached to the drive control line 110) can move freely. Then, when necessary, current can be applied to the motor windings 1332, thereby generating a force 1340 that moves the carriage 1330 in the desired direction (preferably in the direction of lesser force). Another element of this implementation here is that the motor carriage 1330 can be allowed to move freely while maintaining position sensor feedback. Then, since the position sensor data is constantly being acquired, the mode can be switched from the free movement mode back to the active control mode at any time.

[0070] Another detail about air bearings. Figure 5A and Figure 5B In the diagram of , the inventors show a spring to represent the mass of air located between the motor carriage 1330 and the upper guide surface of the top plate 1310. This particular diagram shows the pressure area (P) and vacuum area (V) in a so-called vacuum preloaded air bearing. The pressure area and vacuum area "oppose" each other. The pressure pushes the motor carriage apart, while the vacuum pulls the motor carriage closer. The motor carriage will stay at a certain distance from the upper guide surface at which these two opposing forces are balanced. If the distance from the motor carriage 1330 to the upper guide surface of the top plate 1310 changes, the vacuum and pressure will not balance, and a net corrective force will naturally be generated, which will return the motor carriage 1330 to the original flying height (where the forces were balanced). This will cause the control wire 110 to continuously maintain a substantially zero force unless an external force is applied to the control wire 110.

[0071] Frictionless direct drive using ultrasonic motors

[0072] Another implementation of a frictionless direct drive configuration may be to use a linear ultrasonic motor that can operate in a mode where the contact friction between the carriage and the stator is extremely small due to the application of a control signal. Fig. 6A , Figure 6B and Figure 6C An exemplary embodiment of an ultrasonic motor actuated on a control line 110 is illustrated. Fig. 6A In the embodiment, the steerable medical device 100 is similar to the previously described medical device 100. Figure 1A , 1B , 3 and 4, and the bending control is similar to that of Figure 2A-2C The bending control.

[0073] Fig. 6AIn the embodiment, the motor or actuator is implemented as an ultrasonic piezoelectric drive unit 1400 composed of a sliding block or movable body 1430 and a stator, wherein the stator is composed of a coupling plate 1420 and an oscillating piezoelectric element 1410. The drive unit 1400 is marked as M1, which represents Figure 1A of the motor 1. It is understood that Fig. 6A There are multiple drive units 1400 (e.g., one for each control line). Piezoelectric actuators are transducers that convert electrical energy into mechanical displacement based on the piezoelectric effect. These actuators can be advantageously used as high-precision positioning mechanisms because small mechanical displacements can be controlled at high speeds while generating relatively large forces. For example, The ultrasonic piezoelectric motor can achieve a speed of 500mm / sec at a resolution of 2nm, and has a holding force of up to 15N and a torque of up to 0.3Nm.

[0074] Figure 6B and 6C The application of the ultrasonic drive unit 1400 to the steerable medical device 100 is shown in more detail. In a linear ultrasonic piezoelectric motor, a high-frequency oscillating voltage waveform is applied to the piezoelectric element 1410 under the program control of the controller system 300. The waveform signal induces modal vibration in the coupling plate 1420, and the contact points 1421 and 1422 ("feet") contact the movable body 1430 alternately at high speed. There is a preloaded normal force between the movable body 1430 and the foot contacts 1421 and 1422, which causes instantaneous static friction between one foot and the movable body 1430 (moving plate) at a time when in contact. The path taken by the contact point during this oscillating vibration has components in the vertical and planar or horizontal directions. The vertical movement causes one foot to contact the plate at a time, while the horizontal movement pushes the movable body 1430 in one direction (preferably the longitudinal direction of the control line). Similar to the previous embodiments, the strain and / or position sensor 1431 outputs a signal Xi indicating the amount of strain or displacement (distance) actuated or transmitted by the movable body 1430 to the control wire 110. The feedback signal 1425 is used to control actuation of the steerable instrument 100.

[0075] For example, Figure 6B This shows the initial position where the first leg 1421 contacts the movable body 1430 and causes the movable body 1430 to slide or move in the right direction. Figure 6C 1422 now contacts the movable body 1430 and causes the movable body 1430 to continue to slide or move to the right. The resulting effect is that the movable body 1430 performs a linear motion of a distance 1450, while the strain sensor 1431 continuously monitors the position of the movable body 1430. In this way, when at least one segment of the steerable segment 103 of the steerable instrument 100 is bent, the movable body 1430 can be moved from the first position Z to the final position Z. 0Linear translation (movement) to the second position Z 1 (e.g. due to catheter or endoscope bending).

[0076] Depending on the voltage waveform applied to the ultrasonic motor, different movements and behaviors can be achieved. The movable body 1430 is attached to the control wire 110 so that the control wire 110 can be driven in either direction of the linear motion 1402 at a controllable speed. Position feedback is also constantly monitored by the strain sensor 1431 so that at any point in time, the control system can use the information from the strain sensor 1431 for positioning. The piezoelectric actuator also has the characteristic that when no power is applied to the piezoelectric actuator 1410, there is static friction between the foot and the moving body. This static friction acts as a passive braking force on the drive control wire, which can also be used in a clinical environment to avoid involuntary movement of the end effector. Another behavior of the ultrasonic drive unit 1400 is to have a low friction mode. A specific oscillating voltage signal can be applied to the piezoelectric element 1410 so that the foot (contact points 1421 and 1422) generates a small horizontal force on the movable body 1430 and spends little time in contact with the surface of the movable body 1430. The result is that the ultrasonic actuator behaves more like a low-friction bearing than a friction-driven actuator.

[0077] Similar to the inductive actuator design, the movable body 1430 of the linear ultrasonic motor can move freely in response to the change in the position of the control wire caused by the bending of the catheter. The position of the movable body 1430 is continuously monitored by the strain sensor 1431, and at any time, the control system can switch back to active mode and apply force to the movable body.

[0078] In both cases, the linear motor is directly connected to the control wire 110 and can be moved by small forces from the control wire. The force on the control wire and the displacement of the control wire can be measured independently of each other and independently of the control mode of the motor, and these forces are not disturbed by mode changes because the strain sensors and position sensors are still continuously active even when the driving force is negligible.

[0079] When there is no force on the drive control wire 110, the shape of the device 100 can be easily changed because the control wire is free to translate. For example, external contact of the distal end of the steerable device 100 by certain obstacles, such as the patient's airway wall, can cause the steerable device to bend, which leads to misalignment of the control wire. Once the control wire moves, the strain sensor 1431 provides an output signal to the controller, which triggers the actuator to apply a drive force to the control wire in the opposite direction (the direction of the smaller force).

[0080] The sensing principle of the "strain sensor" in all embodiments can be based on a strain gauge. A known strain gauge is a circuit using a force-sensitive resistor for measuring the compressive or tensile force (strain) applied to an object. When an object is deformed within its elastic limit, it either becomes narrower and longer, or shorter and wider. The result is a change in resistance. The force-sensitive resistor contains a conductive polymer film that changes its resistance in a predictable manner when a force is applied to its surface. The amount of change in resistance value caused gives a measure of the amount of force applied. Strain gauges can have a variety of geometries, including linear strain gauges, shear strain gauges, and the like. There are also semiconductor strain gauges called piezoresistors, nanoparticle strain gauges made of gold-based or carbon-based resistors, and micrometer-scale strain gauges widely used in microelectromechanical systems (MEMS). In other implementations, optical fiber sensors, such as fiber Bragg gratings or Fabry-Perot interferometers, can be used; for example, see patent application publication US 2018 / 0193100, which is included herein by reference for all purposes.

[0081] Of these two implementation modes, embodiments using ultrasonic motors may be more advantageous. Specifically, due to continued advances in ultrasonic motor technology, it is possible to implement a steerable instrument 100 using ultrasonic motors that are lightweight; can achieve micron-scale motion, can be expanded to achieve greater forces without sacrificing speed, and can operate independently of force and position sensing. In addition, ultrasonic motors are very small, allowing them to fit in very compact spaces. Greater speeds can be achieved without affecting the amount of force transfer.

[0082] <Control System and Feedback Control Implementation>

[0083] Fig. 7A An exemplary block diagram of a control system 1500 configured to implement an active-controlled passive bending mode of a steerable medical device 100 in accordance with the present disclosure is illustrated. In the active-controlled passive bending mode, the control system 1500 controls the steerable instrument 100 such that: (1) the force on the control wire 110 is zero when maximum flexibility is desired in the steerable instrument; (2) the force and displacement of the control wire 110 are constantly monitored regardless of the control mode employed; (3) friction in the steerable instrument is minimized even when traveling through a tortuous path during insertion or during withdrawal through such a path; and (4) the proximal end of the control wire 110 is free to translate while connected to its corresponding actuator.

[0084] exist Fig. 7A, the control system 1500 includes a "desired control line position" block 1502, a "motor controller" block 1504, a motor or actuator block 1506, an "actual control line position" 1508, a strain and / or position sensor block 1510, and a comparator block 1512. The control system 1500 is a very simplified form of a feedback control loop that generates an error signal (at the comparator block 1512) based on the difference between the desired position and the actual position (provided by the force / position sensor block 1510). The error signal can also be generated by comparing the desired or previously measured force on the control line with a sudden change in force (e.g., an external force) detected by the strain sensor. The error signal is converted by the motor controller 1504 into a control input signal, which is then sent to the motor or actuator. This is a closed loop control of one of the control lines. Each control line 110 will have its own feedback loop (this is called a single input single output "SISO"). In this case, if it is desired that more than one motor be controlled by one feedback loop, a multiple input / output system is also possible, although such an implementation is not described in this patent application.

[0085] As will be appreciated by those skilled in the art, the control system 1500 may take the form of a pure hardware embodiment, a pure software embodiment (including firmware, resident software, microcode, etc.), or an embodiment combining software and hardware aspects, which may generally be referred to herein as a "circuit," "module," or "system." In addition, some aspects of the control system 1500 may take the form of a computer program product contained in any tangible medium of expression in which computer usable program code is stored. For example, some aspects of the control system 1500 described below with reference to the flowchart examples and / or block diagrams of methods, apparatus (systems), and computer program products may be implemented by computer program instructions. The computer program instructions may be stored in a computer-readable medium that may instruct a computer or other programmable data processing device to operate in a particular manner such that the instructions stored in the computer-readable medium constitute an article of manufacture that includes instructions and processes to implement the functions / actions / steps specified in the flowcharts and / or block diagrams.

[0086] Figure 7B The diagram illustrates functional blocks of a computer 1600 that may operate or be a part of a motor controller 1504 or computer system 400. Figure 7BAs shown in , the computer 1600 may include a central processing unit (CPU) 1601 operably interconnected via a data bus 1605, a memory 1602 including a volatile random access memory (RAM) and a non-volatile read-only memory (ROM), a user input / output (I / O) interface 1603, and a system interface 1604, etc. The computer 1600 can be programmed to issue commands when receiving user input, such as via the user interface 1603, which can be transmitted to various parts of the control system 1600. As part of the user interface 1603, a touch panel screen, a keyboard, a mouse, a steering rod, a control ball and / or a foot pedal may be included. By using the user interface 1603, the user can issue commands that cause the control system 1500 to actively operate the steerable device 100. For example, when a user inputs a command via the user interface 1603, the command is transmitted to the central processing unit CPU 1601 to execute a given program routine, thereby causing the CPU 1601 to send a command to one or more control lines 110 via the system interface 1604, or to prepare to output a signal from one or more strain sensors 221 or 222.

[0087] CPU 1601 may include one or more microprocessors (processors) configured to read and execute computer executable instructions stored in memory 1602. Computer executable instructions may include program code for performing the novel processes, methods, and / or calculations disclosed herein. In particular, computer executable instructions may include instructions for executing the instructions in the memory 1602. Figure 8 , 9 , 10A and 10B to implement program code for actively controlling the passive bending mode of the steerable medical device 100.

[0088] The memory 1602 includes one or more computer-readable and / or writable media, which may include, for example, a magnetic disk (e.g., a hard disk), an optical disk (e.g., a DVD, a Blu-ray), a magneto-optical disk, a semiconductor memory (e.g., a non-volatile memory card, a flash memory, a solid-state drive, a SRAM, a DRAM), an EPROM, an EEPROM, etc. The memory 1602 may store computer-readable data and / or computer-executable instructions.

[0089] System interface 1604 provides an electronic communication interface to input devices and output devices. In particular, system interface 1604 may include one or more circuits, such as a field programmable gate array (FPGA), that interface computer 1600 with motors or actuators that operate control line 110. System interface 1604 may also include a keyboard, display, mouse, printing device, touch screen, light pen, optical storage device, scanner, microphone, camera, drive, communication cables and networks (wired or wireless).

[0090] Figure 8 An exemplary flow chart for implementing an actively controlled passive bending mode of the steerable medical device 100 using a feedback force control loop is illustrated. Figure 8 The process includes the following steps, namely: (a) determining whether the catheter is bent by an external force; (b) reading the tensile / compressive force sensed by a strain or position sensor at the proximal end of the catheter; (c) executing a control algorithm to determine how to move the drive line actuator to reduce the bending force; and (d) determining whether residual bending force on the drive line continues to exist.

[0091] More specifically, Figure 8 The process assumes that the steerable instrument 100 is in active shaft guidance mode, wherein at step 1702, the control system 1500 is performing ongoing steerable instrument guidance. That is, at step 1702, the system monitors the navigation of the steerable instrument during catheter insertion or during removal (withdrawal). At step 1704, the system 1500 reads a signal from a sensor; that is, the system reads a signal from a strain sensor 221 / 222, a position sensor 231 / 232, or from one or more strain sensors and one or more position sensors located at the proximal end of the device. In some embodiments, a strain, position and / or orientation sensor (e.g., EM sensor 115) may also be disposed at the distal end of the steerable instrument 100. At step 1706, the system 1500 continuously monitors the signal from the sensor until it determines whether the steerable instrument is actuated (bent) by an external force other than the active driving force. If the instrument is bent by an external force, "yes" in step 1706, the process proceeds to step 1708. At step 1708, the system 1500 temporarily stops navigation of the steerable instrument 100. At step 1710, the system 1500 initiates an algorithm to determine how to move the motor or actuator to reduce the strain of the force applied to the steerable device. At step 1712, the system 1500 determines whether the bending force is negligible. If the force applied by the external bending force is not negligible ("No" in step 1712), the system 1500 continuously adjusts the force applied to the control line 110 until the external force becomes negligible. If the bending force is negligible (approximately equal to zero), the process proceeds to step 1714, and the control system continues normal navigation of the steerable instrument 100.

[0092] According to one embodiment, in Figure 8During the process, at step 1706, the system transitions from active shape control (active control mode: steps 1702-1704) to passive bending mode (passive control mode: 1708-1712) without losing any key feedback information, such as control line position and control line force (tension or compression). To this end, the system can employ sensor-based mapping techniques in a manner similar to that described in US 2007 / 0135803, where trajectory information is stored in the system's memory and is continuously updated as the instrument moves within the patient's anatomy. However, in the present disclosure, at step 1706, when the system determines that the instrument is bent by an external force, the system enters a passive bending mode, which can be easily transitioned to active shape control, and vice versa, without losing key feedback information such as control line position and control line force (tension or compression). The determination of step 1706 can be based on a comparison made by the system controller between a desired or recorded control line position (or a desired or recorded driving force on the control line) and an actual force or position measured by a sensor. The determination of step 1706 can include a threshold. Specifically, to prevent kinking of the steerable instrument and ensure patient comfort and safety, the user can set a threshold value for the amount of linear displacement, twisting, rotation (or strain) in the software. For example, if the user sets 5% or 10% or 15% as the threshold difference between the desired value and the measured value, the system controller software triggers the change between the active control mode and the passive control mode only when the error exceeds the threshold. The active transition of the steering line from "active" control to "passive" control reduces the system response time without losing key feedback information such as control line position and control line force.

[0093] Fig. 9 An exemplary flow chart for implementing an actively controlled passive bending mode of the steerable medical device 100 using frictionless direct drive is illustrated. Fig. 9 The process includes the following steps, namely: (a) determining whether the catheter is bent by an external force; (b) reading the tensile / compressive force sensed by a strain or position sensor at the proximal end of the catheter; (c) executing a control algorithm to put the actuator in a passive mode so that the actuator itself moves in response to the force applied to the control line; (d) determining whether the bending force on the driving control line is negligible; and (e) returning the actuator to its active mode (engaged with the control line).

[0094] More specifically, Fig. 9 The process is similar to Figure 8 , because it assumes that the steerable instrument 100 is in active axis guidance mode, where the control system 1500 is performing ongoing steerable instrument guidance at step 1802. That is, Fig. 9, steps 1802, 1804, 1806, and 1808 are similar to steps 1702, 1704, 1706, and 1708, respectively. In particular, at step 1806, the system controller determines whether the steerable instrument is bent by an external force other than the conventional navigation force applied by the actuator. At step 1810, the system 1500 initiates an algorithm to place the motor or actuator in a passive mode, in which the actuator stops applying any force to the control line. In this state, if the control line is acted upon by an external force, the actuator is linearly displaced (moved) with minimal friction until the external force applied to the control line 110 becomes negligible (e.g., substantially zero). At step 1812, the system 1500 determines whether the bending force is negligible. If the bending force is negligible (approximately equal to zero), the process proceeds to step 1814, and the control system 150O places the actuator in an active mode (the motor engages the control line) and resumes normal navigation of the steerable instrument 100.

[0095] In another case, the algorithm for releasing (disengaging) the control line can be based on user input. Specifically, in step 1806, the user can determine certain abnormal events in the instrument navigation and manually input a signal to switch from the active control mode to the passive control mode. For example, during navigation, when the catheter is driven through a tortuous path, the catheter may have a propulsion problem and / or a tracking problem; when these problems occur, the system can prompt the user to manually stop active navigation and enter passive control. When the proximal portion of the catheter is further pushed into the lumen access point, but the distal end of the catheter does not move a corresponding distance, a propulsion problem occurs. When the proximal portion is twisted and the distal end is not rotated proportionally as expected, a tracking problem occurs. Propulsion and tracking control are very important aspects of the catheter when navigating through difficult curves and / or obstacles in the patient's anatomical structure. To address these problems, the system can be equipped with an alarm system, such as tactile feedback, or an audible or visual indicator, for example, at the handle 200, so that if the instrument is stuck, the user is prompted to propel and / or track problems.

[0096] In the active control passive bending mode of the steerable medical device 100, an exemplary algorithm for reducing the stretch on the control wire may include the above-mentioned Figure 8 and 9 Similar process discussed. Fig. 10A The diagram illustrates that the same Figure 8 In step 1710, the tensile force (or displacement) is reduced, and in Fig. 9 An exemplary algorithm for releasing the control line in step 1810.

[0097] Fig. 10AIn the example of FIG. 1 , the process begins when the normal navigation of the steerable instrument 100 is temporarily stopped (interrupted) due to the detection of an external force exerting tension in one or more control lines 110. That is, in Figure 8 Step 1710 or Fig. 9 In step 1810, the control system 1500 receives a signal from a strain or position sensor ( Fig. 10A Step 1902). Fig. 10A In the algorithm of FIG. 1904, the system controller reverses the driving direction of the actuator or motor (in Figure 8 In the case of: step 1710), or by releasing the control line (in Fig. 9 In the case of: step 1810), reduce the strain force measured in step 1902. Then, Fig. 10A At step 1906, the system 1500 determines whether the stretch signal indicates a strain force that is approximately zero (or negligible). If the signal from the sensor indicates a value other than approximately zero ("No" at 1906), the system determines whether the steerable device is controlled according to a force control loop or a frictionless direct drive. Figure 8 or Fig. 9 The process continues to reduce the strain force. Once the external force tension is reduced to approximately zero ("yes" at 1906), the active control of the tension force is terminated.

[0098] Fig. 10B The diagram illustrates that based on user input, Figure 8 Step 1710 or Fig. 9 Step 1810 of releases the actuation of one or more control wires 110 (or adjusts the displacement of one or more control wires 110), and an exemplary algorithm for similarly reducing the stretching force. More specifically, as described above, based on external forces monitored by strain and / or position sensors (e.g., due to patient movement) and certain thresholds thereof, a change from an active control mode to a passive control mode, and vice versa, occurs automatically. However, in alternative embodiments, switching between passive / active modes may also be achieved by an operator of the steerable instrument 100. In particular, the passive control mode may help the catheter get rid of a "blocked" condition during navigation through a patient's tortuous anatomical structure (e.g., airway). In this case, when the physician operator determines that the catheter is stuck, the user can stop the active control mode and enter the passive control mode by, for example, pressing a button on the controller, switching the active mode to the passive mode. In the passive mode, the system controller "relaxes" the posture of the catheter so that the catheter can get rid of the "stuck" condition. Afterwards, the operator can return the mode to the active mode and continue to use robotic control.

[0099] Fig. 10BAn exemplary process is illustrated for operating a scenario of user activated controls of the steerable instrument 100 in an active control mode and a passive control mode. Fig. 10B In step 1912, the controller 320 receives an input signal from the user, for example, when the user determines that the steerable instrument 100 may be blocked or stuck in the intraluminal path and presses a control button in the user interface 254 of the handle 200, or manually enters a command through the GUI 422 of the computer system 400. Once the user enters such an input signal, in step 1914, the system controller 320 causes the actuator 310 to disengage and release the control line 110. In step 1915, the strain sensor measures the remaining tensile force in the control line. Then, in step 1916, the system controller determines whether the tensile signal in the control line is approximately zero (or negligible). If the signal from the sensor indicates a value other than approximately zero ("No" in 1916), the system determines that the steerable instrument is stuck and proceeds to step 1918. In step 1918, the system actively reduces the strain force by actuating the control line 110 in the direction of the smaller force. This process of steps 1915, 1916, and 1918 continues until the catheter is relaxed (in passive mode). Once the tension in the control wire is reduced to approximately zero ("yes" at 1906), the passive control mode is ended and the user can return the system to active control mode.

[0100] In the active controlled passive bending mode, there is no active force applied to the control wire 110. When there is no force on the control wire 110, the shape of the steerable instrument 100 can be easily changed because the control wire can translate freely. For example, when something such as an airway wall causes external contact at the distal end of the steerable device 100, such interference can cause unintended bending of the sheath, which causes the control wire to be misplaced and alleviates any possible discomfort or pain for the patient. In contrast, when the control wire 110 is actively bending under the action of the applied tensile force, any external contact may not be detected and therefore cannot be corrected.

[0101] In the event that the steerable instrument may accidentally become blocked or stuck in the patient's anatomy, the user can manually stop the actuation force to place the steerable instrument in a passive associated state. Additionally, under manual operation, if the catheter is passive but still stuck, the system or user can control the actuator to drive the control line in the direction of less force until the catheter becomes unstuck. Thereafter, the operator returns the mode to active mode and continues to use robotic control. Passive mode by manual operation of the user is a very simple judgment made by the system (because the operator makes the judgment to switch modes).

[0102] The actively controlled passive bending mode produces various advantageous effects over known shaft guidance control systems. First, for both embodiments, one of the advantages is that the control lines can be completely passive (capable of being moved by external forces as if they were disconnected from any drive actuator) while still maintaining encoder position feedback and force feedback. In addition, the control line 110 is driven directly by a linear actuator without the need for gears, belts or pulleys, which avoids increased friction and prevents excessive relaxation of the control line. The control line 110 can be actively controlled in both pull and push modes (tension and compression). Thus, an actively controlled passive bending mode can be achieved during insertion and removal (withdrawal) of the steerable instrument 100.

[0103] A particular advantage of the second embodiment is that it differs from using a feedback balanced force because in this case the actuator can be moved passively by the drive wire, which is not affected by sensor noise or velocity issues. In addition, friction is minimized (using unique frequencies and waveforms in the case of ultrasonic motor drive systems and low friction surfaces such as air bearing stages in the case of linear induction motors) to allow the motor moving body to move passively.

[0104] Although all of the embodiments described herein are believed to provide advantages over conventional techniques of active bending modes, the second embodiment is believed to be more advantageous, particularly when using ultrasonic motors. That is, the use of ultrasonic motors to achieve active control of passive bending modes allows for steerable instruments with low moving weight that can be expanded to obtain greater forces without losing speed. In addition, it allows the steerable instrument to operate in active control mode or passive control mode independently of force and position sensing. Since ultrasonic motor technology allows high-precision control through small actuators, the steerable instrument can be very compact. In addition, there is no mechanical tilt, and there is a seamless transition between active shape control and passive bending control, which allows higher speed control without affecting the amount of force transfer.

[0105] <Modifications, Definitions, and Other Embodiments>

[0106] The embodiments of the present invention may also be implemented by a computer of a system or device, the computer reading and executing computer executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be more comprehensively referred to as a "non-transitory computer-readable storage medium") to perform the functions of one or more of the above-mentioned embodiments, and / or including one or more circuits (e.g., application-specific integrated circuits (ASICs)) for performing the functions of one or more of the above-mentioned embodiments, and the method performed by the computer of the system or device, for example, by reading and executing computer executable instructions from a storage medium to perform the functions of one or more of the above-mentioned embodiments, and / or controlling the one or more circuits to perform the functions of one or more of the above-mentioned embodiments. The computer may include one or more processors (e.g., a central processing unit (CPU), a microprocessing unit (MPU)), and may include a network of independent computers or independent processors to read and execute computer executable instructions. Computer executable instructions may be provided to the computer, for example, from a network or a storage medium. The storage medium may include, for example, a hard disk, a random access memory (RAM), a read-only memory (ROM), a storage device of a distributed computing system, an optical disk (such as a compact disk (CD), a digital versatile disk (DVD), or a Blu-ray disk (BD)) TM ), flash memory devices, memory cards, etc. The I / O interface can be used to provide a communication interface to input devices and output devices, which may include a keyboard, a display, a mouse, a touch screen, a non-touch interface (e.g., a gesture recognition device), a printing device, a light pen, an optical storage device, a scanner, a microphone, a camera, a drive, a communication cable, and a network (wired or wireless).

[0107] Where reference is made to the description, specific details are set forth to provide a thorough understanding of the disclosed examples. In other instances, well-known methods, processes, components, and circuits have not been described in detail to avoid unnecessarily prolonging the present disclosure. Unless otherwise defined herein, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. The scope of the present invention is not limited by this specification, but only by the clear meaning of the terms of the claims adopted.

[0108] It should be understood that if an element or component is referred to herein as being on, "against," "connected to," or "coupled to" another element or component, it may be directly on, directly against, connected to, or coupled to another element or component, or there may be intervening elements or components. Conversely, if an element is referred to as being directly on, "directly connected to," or "directly coupled to" another element or component, there may be no intervening elements or components. When used, the term "and / or" may be abbreviated as " / ," and it includes any and all combinations of one or more of the associated enumerated items, if any.

[0109] For ease of description, to illustrate the relationship of one element or feature to other elements or features as illustrated in the various figures, spatially relative terms may be used herein, such as "below," "below," "under," "below," "above," "up," "proximal," "distal," etc. However, it should be understood that, in addition to the orientations shown in the figures, spatially relative terms are intended to include different orientations of the device in use or operation. For example, if the device in the figure is turned over, the elements described as "below" or "below" other elements or features will be oriented to be "above" other elements or features. Thus, relative spatial terms such as "under" may include orientations of above and below. The device may be oriented in other ways (rotated 90° or in other orientations), so that the spatially relative descriptors used herein will be interpreted accordingly. Similarly, the relative spatial terms "proximal" and "distal" may also be interchangeable where applicable.

[0110] The term "about" or "approximately" used herein means, for example, within 10%, within 5%, or less. In some embodiments, the term "about" can mean within the measurement error. In this regard, in the description or claim, all numbers can be understood as if they are preceded by the word "about" or "approximately", even if the term does not appear explicitly. The phrase "about" or "approximately" can be used when describing a value and / or position to indicate that the value and / or position described are within the reasonable expected range of the value and / or position. For example, a numerical value can have a value of ±0.1% of the stated value (or numerical range), a value of ±1% of the stated value (or numerical range), a value of ±2% of the stated value (or numerical range), a value of ±5% of the stated value (or numerical range), a value of ±10% of the stated value (or numerical range), etc. Any numerical range (if listed in this article) is intended to include all sub-ranges included therein.

[0111] The terms "first", "second", "third", etc. may be used herein to describe various elements, components, regions, parts and / or segments. It should be understood that these elements, components, regions, parts and / or segments should not be limited by these terms. These terms are only used to distinguish one element, component, region, part or segment from another region, part or segment. Thus, without departing from the teachings of this article, the first element, component, region, part or segment discussed below may be referred to as the second element, component, region, part or segment.

[0112] The terms used herein are only used to describe specific embodiments and are not restrictive. The singular forms "a", "an", "said" and "the" used herein are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should be further understood that when used in this specification, the terms "include" and / or "comprise" specify the presence of stated features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof that are not explicitly stated. It should be further noted that some claims may be written to exclude any optional elements; such a claim may use exclusive terms such as "only", "only" in conjunction with the enumeration of claim elements, or it may use a "negative" limitation.

[0113] In the example embodiments illustrated in the drawings, specific terminology is employed for clarity. However, the disclosure of this patent specification is not intended to be limited to the specific terminology selected, and it is to be understood that each specific element includes all technical equivalents that operate in a similar manner.

[0114] While the present disclosure has been described with reference to exemplary embodiments, it is to be understood that the present disclosure is not limited to the disclosed exemplary embodiments.The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. A steerable medical device, comprising: An elongated catheter body (100) having at least one bendable section (103) and comprising a plurality of channels (104, 105) extending longitudinally from a proximal end to a distal end of the elongated catheter body (100); a control wire (110) disposed in the first channel (104) of the elongated catheter body (102) and extending to the at least one bendable segment such that a distal end of the control wire is attached to the at least one bendable segment; A sensor (221, 231), wherein the sensor (221, 231) is configured to measure one or more of a strain amount and a displacement amount of the control line (110); an actuator (310) mechanically coupled to a proximal end of a control wire (110) and configured to actuate the elongated catheter body (100) by applying a driving force to the control wire to push and / or pull the at least one bendable segment, wherein the actuator comprises an electric motor (1400) having a movable carriage (1430) and a stator (1420); and a controller (320) configured to interchangeably switch between an active control mode and a passive control mode based on an external force applied to the control line other than the driving force applied by the actuator, or based on a user input, wherein, in the active control mode, the controller controls the actuation of the steerable medical device based on the driving force applied to the control line, Wherein, in the passive control mode, the controller controls the control line to comply with the external force by reducing the driving force applied to the control line by the actuator, so that the control line can be moved by the external force as if the control line is disconnected from the actuator.

2. The steerable medical device according to claim 1, in, In the passive control mode, the controller (320) controls the actuator (310) to move the control wire (110) in a direction opposite to the driving force applied to the control wire (110), so that the control wire (110) is passive, as if the control wire is disconnected from the actuator.

3. The steerable medical device according to claim 1, in, In the active control mode, the controller (320) controls the actuator (310) to apply a driving force to the control wire (110) to actively bend the slender catheter body by displacing the control wire along a first direction, and the sensor outputs a first signal indicating the amount of strain applied to the control wire (110) by the driving force or the amount of displacement of the control wire (110) applied.

4. The steerable medical device according to claim 3, in, In the passive control mode, the controller (320) controls the actuator (310) to stop applying the driving force to the control wire (110), so that the control wire is passive and can be moved by an external force, as if the control wire is disconnected from the actuator.

5. The steerable medical device according to claim 3, in, In the passive control mode, the sensor is configured to output a second signal indicative of an external force applied to the control line, and The controller (320) uses the second signal output from the sensor to cause the actuator (310) to reduce the amount of strain applied to the control line, or to reduce the amount of displacement of the control line.

6. The steerable medical device according to claim 5, in, In the passive control mode, the controller causes the actuator to reduce the driving force applied to the control wire until the amount of strain applied to the control wire is substantially zero, or until the amount of displacement of the control wire is substantially zero.

7. The steerable medical device according to claim 3, in, In the passive control mode, the controller (320) controls the actuator (310) to move the control wire (110) in a second direction opposite to the first direction, so that the control wire (110) is passive, as if the control wire is disconnected from the actuator.

8. The steerable medical device according to claim 1, The sensor includes a strain gauge for measuring the strain amount on the control line and an encoder for measuring the displacement amount of the control line, which are independent of the active control mode and the passive control mode.

9. The steerable medical device according to claim 1, in, In the active control mode, the sensor is configured to measure the amount of strain applied to the control line by the driving force and the amount of strain applied by the external force, and The controller stops the active control mode and enters the passive control mode based on the amount of strain applied by the external force.

10. The steerable medical device according to claim 1, in, In the active control mode, the controller is configured to receive an input signal from the user indicating a malfunction of the steerable medical device, and The controller stops the active control mode and enters the passive control mode based on a signal input by a user.

11. The steerable medical device according to claim 1, The motor is a direct drive motor (312, 1300, 1400) directly coupled to a control line (110).

12. The steerable medical device according to claim 11, wherein the direct drive motor is a linear motor (1300), wherein the controller (320) controls the linear motor (1300) using a command signal (325) based on the external force to apply a substantially zero force on the control line, and in, When the linear motor (1330) is commanded to have substantially zero force, an external force applied to the control wire displaces the moving carriage (1330) of the linear motor, thereby eliminating the strain force applied to the control wire.

13. The steerable medical device according to claim 1, The motor is an ultrasonic motor, and the controller (320) controls the ultrasonic motor using a signal (1425) output from a sensor (1431) or a signal input by a user to minimize contact between the movable slide and the stator, thereby causing a force from a control line to displace the movable slide and eliminate strain applied to the control line.

14. The steerable medical device according to claim 1, in, In the passive control mode, the controller causes the actuator to drive the control wire so that the control wire is passive and is moved by an external force as if the control wire is disconnected from the actuator, while the sensor continues to output a position feedback signal and / or a force feedback signal based on the measured strain or displacement of the control wire (110).

15. The steerable medical device according to claim 1, in, In the active control mode, the at least one bendable segment (103) is configured to be driven through a tortuous path within the lumen in both an insertion direction and a withdrawal direction, and Wherein, in the passive control mode, the controller causes the actuator to drive the control line to have substantially zero strain in the insertion direction and / or the withdrawal direction.

16. The steerable medical device according to claim 1, in, In a passive control mode, the controller causes the actuator to freely translate a control wire along the first channel without actuating the elongate catheter body while the control wire remains connected to the actuator.

17. A non-transitory computer-readable medium storing computer-executable instructions which, when executed by one or more processors, cause a computer to control a steerable medical device (100) according to a method of controlling a steerable medical device (100) interchangeably in an active control mode and a passive control mode, the medical device comprising: An elongated catheter body (100) having at least one bendable segment (103) and comprising a plurality of channels (104, 105) extending longitudinally from a proximal end to a distal end of the elongated catheter body (100); and a control line (110) arranged in the channel (104) of the elongated catheter body (100) and extending to the at least one bendable segment, the control line being attached to the at least one bendable segment, the method comprising: actuating the control wire (110) with a driving force applied by an actuator (310) to bend the at least one bendable section (103) of the elongated catheter body, wherein the actuator (310) comprises an electric motor (1400) having a movable carriage (1430) and a stator (1420); sensing the control wire with a sensor and outputting a signal indicating the amount of strain applied to the control wire (110) or the amount of displacement of the control wire; and The action of controlling the actuator (310) by the controller (320) is interchangeably switched between an active control mode and a passive control mode based on an external force applied to the control line other than the driving force or based on a user input, Wherein, in the passive control mode, the controller controls the control line to comply with the external force by reducing the driving force applied to the control line by the actuator, so that the control line can be moved by the external force as if the control line is disconnected from the actuator.

18. The non-transitory computer readable medium of claim 17, The motor is a direct drive motor (312, 1300, 1400) directly coupled to a control line (110).

19. The non-transitory computer readable medium of claim 18, wherein the direct drive motor is a linear motor (1300), wherein the controller (320) controls the linear motor (1300) using a command signal (325) based on the external force to apply a substantially zero force on the control line, and in, When the linear motor (1330) is commanded to have substantially zero force, an external force applied to the control wire displaces the moving carriage (1330) of the linear motor, thereby eliminating the strain force applied to the control wire.

20. The non-transitory computer readable medium of claim 17, The motor is an ultrasonic motor, and the controller (320) controls the ultrasonic motor using a signal (1425) output from a sensor (1431) or a signal input by a user to minimize contact between the movable slide and the stator, thereby causing a force from a control line to displace the movable slide and eliminate strain applied to the control line.

21. The non-transitory computer readable medium of claim 17, in, In the active control mode, the controller controls actuation of the steerable medical device based on a driving force applied to the control line by the actuator.

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