Cable-driven parallel manipulator control mechanism and related systems and methods

Abstract

A mechanism for two-dimensional actuation and control of a device, such as an interventional device, via a cable drive. The mechanism can include multiple spring-loaded cam followers and a conical control surface acting as a cam. Movement of the conical cam results in vertical linear motion of the cam followers. One end of the cable is connected to the cam followers, and the other end is connected to the target device, so movement of the followers causes cable displacement, resulting in operation of the interventional device. The cable length can be adjusted at a rate determined by the cam, maintaining constant tension and preventing slack. The resulting system, in some embodiments, can be a completely passive mechanism capable of precise device position control, position estimation, and haptic feedback.

Description

[Technical field]

[0001] The present disclosure relates to mechanisms for control and actuation of devices and related systems using cables or ties. Embodiments of the mechanisms have application for steering and tracking of interventional devices for cardiovascular procedures. Embodiments may relate to control and navigation of interventional devices such as guidewires, catheters, needles, and imaging and ablation devices for cardiovascular interventions. Further embodiments relate to steerable robotics for remote camera manipulation applications, continuum robotics applications, inspection and rescue applications, and tight space robotics.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application No. 63 / 123,981, filed December 10, 2020, entitled "CABLE DRIVEN PARALLEL MANIPULATOR CONTROL MECHANISM AND RELATED SYSTEMS AND METHODS," which is incorporated by reference in its entirety.

[0003] References to "cable" throughout this disclosure should be understood to refer broadly to any type of string, wire, or similar operable member, for example made of metal, fabric, polymer, or crystal. [Background technology]

[0004] Past approaches to controlling cable drives in interventional devices have often used motorized winches attached to the cable. These winches utilize position and tension feedback to allow proportional adjustment of the cable length to position the end effector in the workspace as desired. These winches can also be used to maintain optimal tension in the cable and avoid cable sagging (losing tension).

[0005] Generally, a cable-driven mechanism with a given number of cables requires the same number of motors to control the position of the end effector. With this approach, the more cables there are, the more actuators are required, which increases the cost and complexity of control. Since all cables are directly connected to the end effector, there is an inherent interdependence in the interaction of the cables. To place it in the required position, the motors must adjust all the cables, taking into account their interdependent movements. These systems also require a frame that encompasses the available workspace to leverage the tensions from the cables and allow the maneuvering of the end effector. For example, there can be a cable-driven end effector with a two-dimensional planar workspace driven by four cables. To move to any desired position with one motor winding a cable, three other motors must release the corresponding cables. If this is not properly considered, the tensions in the cables can increase and damage the system or reduce its performance and precision.

[0006] Cable-driven systems have a long history in robotics. Typically, many robotic devices are configured as a master / slave system, with the "master" representing the input and the "slave" the output. In the context of this specification, the "master" refers to the way the cable is operated, and the "slave" refers to the device that is controlled and remotely operated. For intuitive operation, it is important that the input actions on the master are similar to the output actions on the slave.

[0007] In the case of cable-driven systems, the cables can utilize an expandable structure as a frame to support the cables for operation of slave devices by actuation of the master input unit. Various applications require the use of multiple cables connected to slaves. The mechanical linkage and interconnection of the cables requires cable ratioing at the input master unit for proper control and actuation of the slaves. In motor-driven systems, this requirement can be addressed by automatic ratio control of the motor, which adjusts the length of each cable at the desired tension. However, passive systems require a solution that takes into account the interdependence of these cables and allows cable lengths to be ratioed while reducing the complexity of the system. A suitable solution is needed that allows for the configuration of passive manual slaves while allowing a simpler solution for motor-driven configurations.

[0008] Therefore, an improved device or solution is desired that allows for control and actuation of cable-driven end effectors of desired devices with high efficiency and convenience, and overcomes past limitations. Summary of the Invention

[0009] Embodiments described or otherwise contemplated herein substantially provide precise control, actuation, and tensioning of cable-driven end effectors of devices, such as interventional devices. The embodiments disclosed herein relate to devices, systems, and methods that allow for the simultaneous actuation of multiple interacting cables to control the position of the device in a two-dimensional plane.

[0010] One embodiment relates to a control mechanism for a cable-driven parallel manipulator with passive cable control. The control mechanism includes a control member, a translation stage, and a cable actuation mechanism. The control member includes a control surface that defines a three-dimensional contour. The translation stage has at least two degrees of freedom (DOF) and is operably coupled to the control member. The cable actuation mechanism is located below the control surface and includes at least one connector mechanism and a plurality of cables. The at least one connector mechanism is constrained to contact the control surface. Each of the plurality of cables has a first end and a second end, the first end connected to one of the at least one connector mechanism and the second end providing a coupling attachment to a device to be controlled. Furthermore, movement of the control member along a two-dimensional plane causes movement of the at least one connector perpendicular to the two-dimensional plane, generating a cable displacement that actuates the device to be controlled in proportion to the movement of the control member.

[0011] One embodiment relates to a device control mechanism for controlling a plurality of cables. The device control mechanism includes a control member having a control surface. The control surface forms a three-dimensional conical recess in a bottom of the control member that functions as a cam guide surface. The device control mechanism includes a translation stage operably coupled to the control member. The device control mechanism further includes a plurality of pistons. Each of the plurality of pistons includes a spring and a roller constrained to contact the guide surface from below. The device control mechanism also includes a plurality of cables, each of the plurality of cables having a first end and a second end, the first end connected to one of the plurality of pistons and the second end connected to a controlled end effector such as an interventional device. The plurality of cables are maintained in tension and are fixed proximate the first and second ends as vertices of corresponding polygonal shapes.

[0012] In certain embodiments, the systems and methods incorporate a control surface (e.g., a three-dimensional conical surface, etc.) coupled to a two-degree-of-freedom motion stage, which acts as a master to provide input to the system. In various embodiments, one end of each included cable is connected to a piston, which is constrained (e.g., by the use of a spring) to contact the control surface. The other end of the cable is coupled to a slave device that is intended to be controlled. As the control surface moves along a two-dimensional plane, the piston moves perpendicular to the plane, resulting in displacement of the cable, which actuates an end effector of the slave, such as the distal tip of a catheter. Such systems and methods allow a user to directly adjust the position of the control surface, which in turn causes a corresponding proportional adjustment of the catheter tip via an attached cable.

[0013] Some embodiments include a mechanism for actuating and controlling an interventional device in two dimensions via a cable-driven mechanism. The mechanism includes a number of spring-loaded cam followers and a conical control surface that functions as a cam. The conical cam moves in two degrees of freedom to cause vertical linear motion of the cam follower. A cable is coupled to the cam follower at one end and to the device of interest at the other end, such that movement of the follower causes cable displacement and ultimately manipulation of an end effector such as an interventional device. This approach allows the length of the cable to be adjusted at a ratio determined by the cam profile, thereby maintaining constant tension and avoiding slack. The resulting system can be a completely passive mechanism that allows for precise device position control, position estimation, and haptic feedback. Potential applications for such a device include interventional surgery and imaging, integration with continuum robotics, remote camera operation, search and rescue applications, and robotics in tight spaces.

[0014] The above summary is not intended to describe each illustrated embodiment or every embodiment of the subject matter of the present specification. The figures and the detailed description that follow more particularly exemplify various embodiments. [Brief description of the drawings]

[0015] The subject matter herein can be more fully understood from the following detailed description of various embodiments considered in conjunction with the accompanying drawings, in which: [Figure 1] FIG. 1 is an isometric view of a control mechanism for a steerable interventional medical device according to one embodiment. [Diagram 2] FIG. 2 is a side view of the control mechanism of FIG. 1 according to one embodiment. [Diagram 3] FIG. 3 is a cross-sectional view of the control mechanism of FIG. 1 according to one embodiment. [Figure 4A] FIG. 4A is a side cross-sectional view of the control mechanism of FIG. 1 in an alternating position, illustrating modified steering tension, according to one embodiment. [Figure 4B] 4B is a side cross-sectional view of the control mechanism of FIG. 1 in alternating positions showing different modified steering tensions according to one embodiment. [Figure 5A] FIG. 5A is a cross-sectional end view of the control mechanism of FIG. 1 in an alternating position according to one embodiment. [Figure 5B] 5B is a cross-sectional end view of the control mechanism of FIG. 1 in an alternating position, according to one embodiment. [Figure 6] FIG. 6 is an isometric view of control functions for a steerable interventional medical device, according to one embodiment. [Figure 7] FIG. 7 is a side view of the control mechanism of FIG. 6, according to one embodiment. [Figure 8] FIG. 8 is a side cross-sectional view of the control mechanism of FIG. 6, according to one embodiment. [Figure 9A] FIG. 9A is a side cross-sectional view of the control mechanism of FIG. 6 in an alternating position, illustrating modified steering tension, according to one embodiment. [Figure 9B] 9B is a side cross-sectional view of the control mechanism of FIG. 6 in an alternating position, illustrating different modified steering tensions, according to one embodiment. [Figure 10A] FIG. 10A is a cross-sectional end view of the control mechanism of FIG. 6 in an alternating position according to one embodiment. [Figure 10B]FIG. 10B is a cross-sectional end view of the control mechanism of FIG. 6 in an alternating position according to one embodiment. [Figure 11A] FIG. 11A is a schematic diagram of an example illustrating the positioning of a three-dimensional control surface that can be used to control the positioning of a catheter tip in a two-dimensional plane, according to one embodiment. [Figure 11B] FIG. 11B is a schematic diagram of an example illustrating the positioning of a three-dimensional control surface that can be used to control the positioning of a catheter tip in a two-dimensional plane, according to one embodiment. [Figure 11C] FIG. 11C is a schematic diagram of an example illustrating the positioning of a three-dimensional control surface that can be used to control the positioning of a catheter tip in a two-dimensional plane, according to one embodiment. [Figure 11D] FIG. 11D is a schematic diagram of an example illustrating the positioning of a three-dimensional control surface that can be used to control the positioning of a catheter tip in a two-dimensional plane, according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] While various embodiments are susceptible to various modifications and alternative forms, details thereof are illustrated by way of example in the drawings and described in detail below. It should be understood, however, that the intention is not to limit the claimed subject matter to the specific embodiments described in the specification. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the subject matter defined by the claims.

[0017] Detailed Description of the Drawings The embodiments disclosed herein include mechanisms for actuation and control of a cable-driven end effector. The proposed system may include a variety of features, such as a control member having a control surface, a motion stage system (i.e., axis system), and a cable actuation mechanism having at least one connector mechanism, such as a spring-actuated piston or lever. Additionally, the embodiments may include modifications such as the addition of a gearbox or encoder to track the displacement of the cable.

[0018] 1-5B depict a control mechanism 100 according to one embodiment. The control mechanism 100 may also be referred to and understood at times in this disclosure as a "steering mechanism." Additionally, the control mechanism 100 may also be understood at times throughout this disclosure and claims as a "cable-driven parallel manipulator control mechanism" or a "device control mechanism" that provides passive cable control. Such a cable-driven parallel manipulator control mechanism may provide passive cable control in some embodiments. Similarly, a device control mechanism may be understood to control multiple cables.

[0019] In various embodiments, control mechanism 100 includes a control member 110 having a control surface 112 (in a recessed lower portion) and an input surface 114 (on an upper portion) mounted on a motion stage (specifically, two-axis rail system 120 of FIGS. 1-5B), and a cable actuation mechanism 130 located below control surface 112. It should be understood that in some embodiments, a user may provide input to control mechanism 100 using user manipulation of input surface 114, such as by moving a thumb. Control mechanism 100 may be part of a steering wheel or other user control in some embodiments.

[0020] 2 is a side view of the control mechanism 100 according to one embodiment. As shown, the two-axis rail system 120 is comprised of two upper shafts 121 mounted on upper shaft mounts 122. The two-axis rail system 120 may be more generally understood to be a two-degree-of-freedom system on which the control member 110 is mounted and operatively slides. The two-degree-of-freedom system is not limited to merely a two-axis rail system for purposes of this disclosure. The control member 110 slides on the upper shafts 121. The upper shaft mounts 122 slide on two lower shafts 123 mounted on lower shaft mounts 124. The cable actuation mechanism 130 is generally located at the base of the control mechanism 100 and is shown to include a cable 131 and a mounting block 132.

[0021] 3 is a side cross-sectional view of the control mechanism 100, according to one embodiment. As shown, the cable actuation mechanism 130 is depicted in cross-section. Although not all pistons are visible in FIG. 3, it should be understood that the cable actuation mechanism 130 includes four pistons 133, each having a spring 134 and a roller 135.

[0022] In some embodiments, the piston 133 is not present, and instead there is at least one connector mechanism of some other type. In some embodiments, the at least one connector mechanism can be a lever or other mechanism for connecting a cable to the surface. For example, a lever can be used with a spring on one end that is constrained by the control surface.

[0023] As the control member 110 slides on the two-axis rail system 120, the spring 134 holds the roller 135 in contact with its control surface 112. The control surface 112 forms a three-dimensional profile. In this particular example, the three-dimensional profile can be a three-dimensional conical concave shape, and thus can generally function as a cam for the mechanism. The conical shape of the control surface 112 provides a useful structure for ensuring the necessary cable displacement to provide tension and to transmit the ratio adjustment to the target device. See Figures 11A-D and the discussion therein relating to the conical shape of the control surface 112. Other three-dimensional shapes (profiles) are conceivable and may be possible as well.

[0024] The roller 135 may generally function as a cam follower. The roller 135 may rotate freely, reducing frictional wear on the control surface 112. The piston 133 has a lip for retaining the roller 135. As the piston 133 moves within the mounting block 132, the cable 131 is actuated with an associated displacement. The cable 131 passes through a cable guide 136 to actuate an end effector (or other feature of an interventional device attached to the end of the cable 131) to a required position in relation to the embodiment.

[0025] 4A and 4B are side cross-sectional views of control mechanism 100 with control surface 112 in an alternating position, according to one embodiment. Piston 133 is shown actuated with spring 134 restraining roller 135 into contact with control surface 112.

[0026] 5A and 5B show cross-sectional end views of control mechanism 100 with control surface 112 in an alternating position, according to one embodiment. Piston 133 is shown actuated with spring 134 restraining roller 135 into contact with control surface 112.

[0027] 6-10B show another embodiment of a control surface actuated control mechanism 200, which may sometimes be additionally referred to and understood in this disclosure as a "steering mechanism." In various embodiments, the control mechanism 200 includes a control member 210 having a control surface 212 (within a lower recess) and a joystick 225 (at an upper portion) attached to a motion stage (specifically, a planar roller system 220 in FIGS. 6-10B), and a cable actuation mechanism 230 located below and within the recess formed by the control surface 212.

[0028] FIG. 7 is a side view of the control mechanism 200 according to one embodiment. In one embodiment, the planar roller system 220 (which provides a two-degree-of-freedom translation stage) includes an upper roller surface 221 mounted on a mounting plate 224 by two vertical supports 222. Other two-degree-of-freedom translation stages are possible. The control member 210 is sandwiched between the upper roller surface 221 and a piston block 223, and the large roller 227 and small roller 228 distribute the load at the contact point. A joystick 225 is connected to the control member 210 by a joystick mount 226, allowing a user to manually actuate the control member 210 and its control surface 212. When the control member 210 is actuated, the large roller 227 and small roller 228 roll to reduce friction. The cable actuation mechanism 230 includes a cable 231 and a guide block 232 as shown.

[0029] FIG. 8 is a side cross-sectional view of the control mechanism 200 according to one embodiment. As shown, the cable actuation mechanism 230 includes, in cross section, four pistons 234, each with a spring 235 and a roller 237. Specifically, in this embodiment, the roller 237 is a ball. The spring 235 holds the roller 237 in contact with the control surface 212 as it moves on the planar roller system 220. The control surface 212 forms a three-dimensional conical recess and accordingly can generally function as a cam for the mechanism. As previously explained, the conical shape of the control surface 212 can be advantageous and useful for this purpose. The cable 231 is fixed in the piston 234 by the cable mount 236. The cable 231 moves on the guide shaft 233 through a cable guide in the guide block 232, which reduces friction for the cable 231. As the piston 234 moves in the piston block 223, the cable 231 is actuated by an associated displacement. The cable 231 continues to its termination point to actuate an end effector (or other feature of an interventional device attached to the cable 231) to the desired position relative to the embodiment.

[0030] 9A and 9B are side cross-sectional views of a control mechanism 200 with a control member 210 and its control surface 212 in alternating positions, according to one embodiment. The piston 234 is shown actuated with a spring 235 urging a roller 237 into contact with the control surface 212.

[0031] 10A and 10B are cross-sectional end views of a control mechanism 200 with a control member 210 and its control surface 212 in alternating positions, according to one embodiment. The piston 234 is shown actuated with a spring 235 urging a roller 237 into contact with the control surface 212.

[0032] The following discussion and Figures 11A-D show a shape for a three-dimensional control surface that can be used to control the positioning of an end effector of a desired device (such as a catheter tip) in a two-dimensional plane, which is shown to be an inverted cone shape. Additionally, the required shape of the handle and the relationship between user input and the resulting movement of the end effector are shown to correspond.

[0033] Here, the end effector is operated by multiple cables, each of which uses one anchor as a lever. The control surface must change the length of the cable at the handle to match the change in length of the cable at the end effector. Here, the control surface is called the master and the end effector is called the slave. Their corresponding coordinate systems are denoted by the superscripts m and s, respectively.

[0034] Let the gear ratio between the slave and the master be α, i.e., if you shorten the cable by 1 mm on the master side, the gearing system will shorten by α mm on the slave side.

number

[0035] Slave side i th The anchor coordinates are JPEG0007606613000002.jpg1536, and the coordinates of the corresponding piston in the handle are JPEG0007606613000003.jpg1538 and both are assumed to be constant. This explanation is given with full generality, so it can be applied to any of several cables (values ​​of i) individually. In the figure, the explanation focuses on the right-most cable.

[0036] The displacement of the control surface is (x m ,y m ) and is considered arbitrary. The resulting displacement of the catheter tip is (x s ,y s), which is a function of the fixed geometry (i.e., the anchor and piston positions and the control surface equations) as well as the current displacement of the surface.

[0037] Slave side (2D plane): The change in the slave cable length is the initial cable length (L 0 ) and calculate the final cable length (L f ) is calculated by subtracting

number

[0038] Using the Pythagorean theorem, the initial (FIG. 11A) and final (FIG. 11B) cable lengths of the anchor can be determined. The following equations are given by i th where i is arbitrary.

number

[0039] Master side (3D surface): The cables are individually constrained to the control surfaces via the pistons. They are fixed at their positions x and y (similar to the anchors on the catheter side), so that the position z of the cables is determined by the height of the control surface at that position. The control surface is free to move along the x and y axes. The change in cable length is a function of the initial vertical position (z 0 ) (shown in FIG. 11C) and use it to calculate the final vertical position of the cable (z f ) (shown in FIG. 11D).

number

[0040] The initial (FIG. 11A) and final (FIG. 11B) positions x and y of the piston relative to the (control) surface centre can be determined. The final x,y position also depends on the displacement of the surface. This puts the position in terms of an equation for the height of the surface as a function of x and y.

number

[0041] JPEG0007606613000008.jpg1117 and The relationship between α and 1117 is due to the maintenance of cable length. A negative relationship arises because increasing the cable length at the handle decreases the cable length at the catheter tip. Furthermore, due to gearing, increasing the cable length at the handle by α millimeters requires decreasing the cable length at the catheter tip by 1 millimeter. Therefore,

number

number

[0042] Therefore, to elegantly fit both sides of this equation together, the following surface equation is well suited:

number

[0043] This is the equation for a cone with a slope of 1 as claimed. The height offset H 0 is arbitrary and has no bearing on the outcome, so you can use any convenient height offset.

[0044] Furthermore, this approach suggests that the shape of the piston in the handle should be a reduced version of the shape of the anchor at the catheter tip.

number

[0045] Furthermore, it explicitly states that the catheter tip displacement is a magnified version of the control surface displacement.

number

[0046] The cone inclination may be changed to a value other than 1. For example, changing the inclination to 2 will double the cable displacement, which can be combined with a 1 / 2 gear ratio in the tensioning system to keep the overall power output the same. This can be useful as it reduces the required handle width, improving ergonomics.

[0047] Thus, the use of a three-dimensional conical shape for the control surface 212, as illustrated by this description and by FIGS. 11A-D, provides a desirable physical structure for the control mechanism and can result in a particularly useful device.

[0048] The control mechanisms (e.g., 100, 200, etc.) are widely applicable to cable-driven devices. Furthermore, cable-driven master / slave systems have many applications. One application can be found in minimally invasive catheter-based procedures. These procedures are typically guided by flexible elongated members that can be manipulated from outside the body with two degrees of freedom, limiting the available workspace. Using cable-driven end effectors instead can provide additional degrees of freedom and improve maneuverability. Furthermore, due to the direct mechanical connection, the operator can also receive haptic feedback from the end effector.

[0049] Another potentially relevant embodiment and application of catheters such as these is in forward-looking imaging probes. One of the main limitations of miniaturizing imaging probes is the limited space available at the tip of the miniaturized device, thus restricting the ability to integrate sensors or transducers that allow for a large field of view (FOV). Using a cable-driven catheter that utilizes a stretchable structure, a transducer or sensor with a small field of view can be advanced and measured at multiple locations. Using the position data obtained from the sensors, multiple readings can be combined into one image with a large FOV. This can be applied to a variety of imaging modalities, such as ultrasound and optical coherence tomography (OCT).

[0050] It can also be used for robotic manipulation in tight spaces. In some embodiments, continuum robots can be used to access hard-to-reach areas while allowing precise remote control of the end effector. Potential applications for robots in tight spaces include search and rescue, industrial and nuclear maintenance robots, aerospace and automotive manufacturing, and endoscopy.

[0051] As discussed above, embodiments of the proposed system and method generally incorporate a control surface (e.g., a three-dimensional conical surface) coupled to a two-degree-of-freedom motion stage, which acts as a master to provide input to the system. In one embodiment, one end of each included cable is connected to a piston that is constrained (e.g., by use of a spring) in contact with the control surface. The other end of the cable is coupled to the slave device to be controlled. As the control surface moves along a two-dimensional plane, the piston moves perpendicular to that plane, displacing the cable and thereby actuating a slave end effector, e.g., the distal end of a catheter. This system allows a user to directly adjust the position of the control surface, which in turn allows a corresponding proportional adjustment to the tip of the catheter via an attached cable.

[0052] In some embodiments, the cable can be connected to a gearing system before transitioning to the slave. As mentioned before, this has the effect of changing the (geometric) shape, so that for a given displacement of the end effector a proportionally smaller displacement of the control surface is required. This allows the footprint of the master control to be tailored to the application. In another embodiment, the system can be adapted to increase the amount of force applied to the end effector of the interventional device. Additionally, this can be used to adjust the resolution between the master and the slave.

[0053] The control mechanism (e.g., 100, 200, etc.) can be constructed such that the dimensional displacement of the control surface is proportional in both direction and magnitude to the displacement of, for example, the end effector. Additionally, the position and shape of the piston in the master is proportional to the shape of the cable anchor point on the slave frame. Also, the position and shape of the center of the cylinder relative to the piston in the master is proportional to the position and shape of the end effector relative to the extension anchor of the slave. The proportionality constant is the gear ratio between the master and slave mechanisms.

[0054] In some embodiments, only four cables may be used to actuate the device. Typically, in this scenario, the anchor points in the slave's frame will have a square shape. This allows maximum coverage of the total area with only four anchor points for the cables. Correspondingly, the four pistons moving perpendicular to the conical surface on the master side are also arranged in a square shape. However, the proposed system is more general and any number of anchors can be arranged at any position. For example, in some embodiments, the anchors can be arranged at the vertices of a regular polygon with an increasing number of sides. There will then be a corresponding number of cables and the pistons in the master will be arranged in the corresponding polygon. This has the advantage that as the number of vertices of the polygon increases, the end effector can traverse a larger percentage of a circular cross-sectional area.

[0055] In one embodiment, position sensors including devices such as linear or rotary encoders can be added to the master to track the position of a control surface or the displacement of a cable. In such an embodiment, the sensor data can be used to visualize the position of the slave device or end effector relative to its available workspace and displayed to the operator via a user interface.

[0056] In one embodiment, the control mechanism (e.g., 100 or 200) can be applied to a cable-driven steerable catheter with an expandable frame, such as the steerable catheter configuration disclosed in WO 2019 / 213215 A1 by Tavallaei et al. The expandable frame can be used as a rigid lever for the cable to actuate an end effector, such as the distal tip of the catheter. This allows for a fully mechanical solution of the master side of the catheter. Position sensors (including linear or rotary encoders, etc.) can also be used to track the catheter tip and provide feedback to the user.

[0057] Also, in one embodiment, a forward-looking imaging transducer can be attached to the end effector. In such an embodiment, the end effector can be moved to various positions and the imaging probe can be used along with the positioning data to reconstruct an image with a large field of view (FOV). This can be applied to catheters as discussed in the previous embodiment, or to robots in limited workspaces for search and rescue applications or imaging systems in hard-to-reach spaces. Various imaging modalities or sensors can be integrated into the system. Examples include, but are not limited to, optically based sensors, ultrasonic transducers, or radiation sensors. In such an embodiment, linear, rotary actuators, or motors can be used to move the position of the control surface on the master. This is particularly useful for imaging probes as it allows the probe to sweep across a cross section and reconstruct an image autonomously.

[0058] As a further embodiment, where the use of a motorized design is permitted, the use of a control surface can reduce the number of motors required to as few as two, required to control the two dimensional movement of the control surface.

[0059] Also, in one embodiment, the cables can be attached to the control surface at one point. Different types of designs are possible, for example with three cables and very thin surfaces. In this embodiment, the control surface is a three-dimensional surface that accommodates the required length changes for the individual cables at a single attachment point. In such an embodiment, the cables are constrained to the surface, and as the attachment point for the cables moves on the three-dimensional surface, the length of the cables on the surface changes proportionately, resulting in the slave device being controlled in the desired two-dimensional surface. For other embodiments, alternative attachment methods can be utilized for either the end effector or control side cables. According to these embodiments, the attachment methods can be described using various three-dimensional control surfaces.

[0060] The proposed method can also be used to actuate a continuous cable-driven manipulator actuated by multiple cables. For example, a deflectable catheter that is cable-driven and can redirect its distal end using one or more cables can use the same strategy: a cam surface (also referred to herein as a "cam guide surface") can be coupled to the cable so that the movement of the cam surface can adjust the length of the cable. This allows a passive remote actuation method, providing a mapping between the manipulation of the master unit and the movement of the catheter tip based on the contour of the cam surface.

[0061] Various embodiments of systems, devices, and methods have been described herein. These embodiments are provided by way of example only and are not intended to limit the scope of the invention as claimed. It should be understood that the various features of the described embodiments can be combined in various ways to create numerous additional embodiments. Furthermore, while various materials, dimensions, shapes, configurations, and arrangements, etc., have been described for use in the disclosed embodiments, other than those disclosed may be utilized without departing from the scope of the invention as claimed.

[0062] Those skilled in the relevant art will understand that the subject matter herein may include fewer features than those shown in the individual embodiments above. The embodiments described herein do not represent an exhaustive suggestion of how various features of the subject matter herein may be combined. Thus, the embodiments are not combinations of mutually exclusive features, but rather various embodiments may include combinations of different individual features selected from different individual embodiments, as would be understood by one skilled in the art. Furthermore, elements described with respect to one embodiment may be implemented in other embodiments, unless otherwise noted in such embodiment.

[0063] Although a dependent claim may refer to a specific combination with one or more other claims in the claim, other embodiments may likewise include combinations of the dependent claim with the subject matter of each other dependent claim, or combinations of one or more features with other dependent or independent claims, and such combinations are suggested herein unless it is specifically stated that such combinations are not intended.

[0064] The incorporation by reference of the above documents is limited such that no subject matter contrary to the express disclosure of this specification is incorporated herein. The incorporation by reference of the above documents is further limited such that no claims contained in the documents are incorporated herein by reference. The incorporation by reference of the above documents is further limited such that any definitions provided in the documents are not incorporated herein by reference unless expressly included herein.

[0065] For purposes of claim interpretation, it is expressly intended that the provisions of 35 U.S.C. §112(f) not be invoked unless the specific terms "means" or "step" are recited in a claim.

Claims

1. 1. A cable-driven parallel manipulator control mechanism that provides passive cable control, comprising: a control member having a control surface, the control surface defining a three-dimensional contour; a translation stage having at least two degrees of freedom and operably coupled to the control member; a cable actuation mechanism, the cable actuation mechanism being located below the control surface; The cable actuation mechanism includes at least one connector mechanism and a plurality of cables, the connector mechanism being constrained in contact with the control surface, each of the cables having a first end and a second end; a first end adapted to connect to one of the at least one connector mechanism and a second end adapted to provide a mating attachment to a device to be controlled; A cable driven parallel manipulator control mechanism, wherein movement of a control member along a two dimensional plane causes movement of at least one connector mechanism perpendicular to the two dimensional plane, resulting in displacement of the cables in response to movement of the control member, thereby moving a controlled device.

2. 2. The cable-driven parallel manipulator control mechanism of claim 1, wherein the controlled device is an interventional device.

3. 2. The cable-driven parallel manipulator control mechanism of claim 1, wherein the three-dimensional contour is a conical recess.

4. 10. The cable-driven parallel manipulator control mechanism of claim 1, wherein at least one connector includes a plurality of pistons, each piston including a spring and a roller constrained to contact a control surface.

5. 10. The cable-driven parallel manipulator control mechanism of claim 1, wherein at least one connector includes a lever that constrains a spring at one end.

6. 2. The cable-driven parallel manipulator control mechanism of claim 1, wherein the motion stage is a two degree of freedom system, and the control member is attached to the motion stage, and the control member operatively slides on the motion stage.

7. 7. The cable-driven parallel manipulator control mechanism of claim 6, wherein the two degree of freedom system includes two upper shafts attached to two upper shaft mounts; A cable-driven parallel manipulator control mechanism in which two upper axis mounts slide on two lower axes attached to two lower axis mounts.

8. 2. The cable-driven parallel manipulator control mechanism of claim 1, wherein the motion stage is a planar roller system, the control member is mounted on the planar roller system, and the control member operatively slides on the planar roller system.

9. 9. The cable-driven parallel manipulator control mechanism of claim 8, wherein the planar roller system includes an upper roller surface, a plurality of vertical supports, and a mounting plate.

10. 10. The cable-driven parallel manipulator control mechanism of claim 1, wherein the cable actuation mechanism includes a mounting block.

11. 10. The cable-driven parallel manipulator control mechanism of claim 1, further comprising a gearing system connected to the plurality of cables.

12. 12. The cable-driven parallel manipulator control mechanism of claim 11, wherein the gearing system gears to increase the magnitude of force applied to the interventional device.

13. 2. A cable-driven parallel manipulator control mechanism according to claim 1, wherein the position of the control member is joystick operated.

14. 10. The cable-driven parallel manipulator control mechanism of claim 1, wherein the cable-driven mechanism includes a cable guide.

15. 10. The cable-driven parallel manipulator control mechanism of claim 1, wherein the cable-driven mechanism comprises a piston block.

16. 10. The cable-driven parallel manipulator control mechanism of claim 1 , further comprising a plurality of position sensors for tracking a position of at least one of the control surfaces and for tracking a displacement of at least one of the plurality of cables.

17. 10. The cable-driven parallel manipulator control mechanism of claim 1, wherein the controlled device is a cable-driven steerable catheter having an expandable frame.

18. 2. The cable-driven parallel manipulator control mechanism of claim 1, wherein the plurality of cables of the cable drive mechanism includes three or more cables that are fixed to a polygon-shaped cable drive mechanism.

19. 10. The cable-driven parallel manipulator control mechanism of claim 1, wherein the controlled device comprises a forward looking imaging transducer.

20. 10. The cable-driven parallel manipulator control mechanism of claim 1, wherein the device being controlled is a catheter.

21. 10. The cable-driven parallel manipulator control mechanism of claim 1, wherein the device being controlled is a robotic device for search and rescue applications.

22. 10. The cable-driven parallel manipulator control mechanism of claim 1, wherein a rotary actuator is used to move the position of the control surface.

23. A device control mechanism for controlling a plurality of cables, comprising: a control member having a control surface, the control surface forming a three-dimensional conical recess at a bottom of the control member which acts as a cam guide surface; a translation stage operatively connected to the control member; a plurality of pistons, each including a spring and a roller constrained to contact a guide surface from below; a plurality of cables, each having a first end and a second end, the first end connected to one of the plurality of pistons and the second end connected to an end effector to be controlled; A device control mechanism, in which a plurality of cables are maintained in tension and are fixed at first and second ends as vertices of corresponding polygonal shapes.

24. 24. The device control of claim 23, wherein the motion stage is a two degree of freedom system, and the control member is mounted to the motion stage such that the control member operatively slides on the motion stage.

25. 24. The device control mechanism of claim 23, wherein the motion stage is a two degree of freedom planar roller system, and the control member is attached to the planar roller system such that the control member operatively slides on the planar roller.

26. 24. The device control of claim 23, wherein the plurality of pistons comprises at least three pistons.

27. 24. The device control of claim 23, further comprising a gearing system connected to the plurality of cables.

28. 24. A device control as claimed in claim 23, wherein the position of the control member is joystick operated.

29. 24. A device control as claimed in claim 23, including a plurality of position sensors for tracking the position of at least one of the control surfaces and the displacement of at least one of the plurality of cables.

30. 24. The device control of claim 23, wherein the end effector being controlled is an interventional device.

31. 31. The device control of claim 30, wherein the interventional device is a cable driven steerable catheter having an expandable frame.

32. 31. The device control of claim 30, wherein the interventional device includes a forward looking imaging transducer.

33. 24. A device control as claimed in claim 23, wherein an actuator or motor is used to move the position of the control surface.

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