Continuous body robot control system and continuous body robot control method

Abstract

In the present invention, a control unit device, which controls the operation of a continuum robot (100) including a bendable unit (170) having a plurality of bending sections (171 to 173), defines, as an origin point (O3), a predetermined position on a wire guide (1721) located at a farthest position of a base portion (140) in a second bending section (172, which is a subsequent bending section), the reference axes x3, y3, and z3 are set for a direction in which the wire guide 1721 faces, and a drive unit in the base portion 140 is caused to drive the wire 1732 of the third bending section 173, which is a distal bending section, so that the third bending section 173, which is a distal bending section, is bent based on a relative coordinate system 1730 in which the reference axes x3, y3, and z3 are aligned with each other. The origin point O3 and the reference axes x3, y3, and z3 related to the wire guide 1721 change according to the movement of the continuum robot 100.

Description

Technical Field

[0001] The present invention relates to a continuum robot control system and a continuum robot control method for controlling the actions of a continuum robot. Background Art

[0002] A continuum robot has a bendable unit consisting of multiple curved segments with flexible structures. The shape of the continuum robot is controlled by deforming the curved segments. Continuum robots offer two main advantages over robots configured with rigid links. The first advantage is that continuum robots can move along curves in confined spaces or in environments with scattered objects, where rigid-link robots might become stuck. The second advantage is that, due to the continuum robot's inherent softness, it can be manipulated without damaging delicate objects.

[0003] Continuum robots do not necessarily need to detect external forces, as rigid-link robots do. This feature holds promise for applications in healthcare, such as endoscope sheaths and catheters, and in extreme work robots, such as rescue robots.

[0004] Patent document 1 describes a control method for controlling a bendable unit of a continuum robot used as an endoscope when the bendable unit enters a narrow space. More specifically, in Patent document 1, for all pairs of adjacent bending segments in the bendable unit, control (leader following control) is performed so that as the base of the endoscope moves forward, the bending shape of the subsequent bending segment follows the bending shape of the preceding bending segment, and thus the shape of the endoscope propagates continuously. In this case, according to Patent document 1, the bending angle of the most distal (front) bending segment is continuously propagated to the subsequent bending segment over a virtual segment length that is less than the actual bending segment length. Therefore, an instruction is sent so that the bending angle of the subsequent bending segment is closer to the bending angle of the preceding bending segment. Therefore, contact with surrounding obstacles is less likely to occur in a narrow space, thereby facilitating entry into a narrow space path.

[0005] Citation List

[0006] Patent Literature

[0007] Patent Document 1: U.S. Patent No. 11103992 Summary of the Invention

[0008] Technical issues

[0009] In Patent Document 1, in the above-mentioned leader-following control, a coordinate system is established on a sliding table on which a continuum robot is fixed and moves back and forth, and the bending angles of all bending sections are determined based on this coordinate system. The technology described in Patent Document 1 makes the operation performed by the operator easier because when the operator is able to look down at the continuum robot, they can grasp the correspondence between the coordinate system for operating a bendable unit having multiple bending sections and the coordinate system for the front end of the continuum robot. In addition, the amount of calculation in the control system is reduced. However, according to the technology described in Patent Document 1, for example, when an operator who is unable to look down at the continuum robot and has a camera installed at the farthest end of the continuum robot operates the bendable unit while observing the camera image, it is difficult for the operator to intuitively operate the bendable unit because it is difficult to grasp the bending condition of the subsequent bending section.

[0010] Therefore, an object of the present invention is to provide a mechanism that enables an operator to intuitively operate a bendable unit of a continuum robot.

[0011] Solution to the problem

[0012] According to the present invention, a continuum robot control system includes: a continuum robot, the continuum robot including: a bendable unit, the bendable unit having a plurality of bending segments, each of the plurality of bending segments being configured to be bent by a driven linear member; a base, the base being configured to support the bendable unit; and a drive unit, the drive unit being configured to drive the linear member, wherein the plurality of bending segments of the bendable unit include a distal bending segment and a subsequent bending segment, the distal bending segment being located distal to the base and including a distal fixing member located at the farthest side of the base in the distal bending segment and a distal linear member serving as a linear member fixed to the distal fixing member and driven by the drive unit, the subsequent bending segment being located between the distal bending segment and the base and including a subsequent fixing member located at the farthest side of the base in the subsequent bending segment and a subsequent linear member serving as a linear member fixed to the subsequent fixing member and driven by the drive unit; and a control unit, the control unit being configured to control the movement of the continuum robot. The control unit defines a predetermined position on the subsequent fixing member as an origin, sets a reference axis for a direction faced by the subsequent fixing member, and causes the driving unit to drive the distal linear member so as to bend the distal bending section based on a relative coordinate system in which the origin and the reference axis associated with the subsequent fixing member change according to the movement of the continuum robot.

[0013] Furthermore, the present invention includes a continuum robot control method using the above-mentioned continuum robot control system.

[0014] Advantageous Effects of the Invention

[0015] According to the present invention, when operating the bendable unit of the continuum robot, the operator can intuitively operate the bendable unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 An example of a schematic configuration of a continuum robot according to a first embodiment of the present invention is shown.

[0017] Figure 2 Shown Figure 1 An example of a detailed schematic configuration of one of the curved sections in the schematic configuration of the continuum robot is shown.

[0018] Figure 3 Shown Figure 2 An example of the arrangement of three wires (a-wire to c-wire) in the xy plane is shown.

[0019] Figure 4 An example of a schematic configuration of a continuum robot control system according to a first embodiment of the present invention is shown.

[0020] Figure 5 The first embodiment of the present invention is shown, and Figure 1 An example of a kinematic model of a continuum robot is shown.

[0021] Figure 6 The first embodiment of the present invention is shown, and Figure 1 An example of a kinematic model of a continuum robot is shown.

[0022] Figure 7 An example of leader-following control of a continuum robot according to the second embodiment of the present invention is shown.

[0023] Figure 8 An example of a schematic configuration of a continuum robot control system according to a second embodiment of the present invention is shown.

[0024] Figure 9A The second embodiment of the present invention is shown and the Figure 8 The control unit shown performs leader-follower control.

[0025] Figure 9B The second embodiment of the present invention is shown and the Figure 8 The control unit performs leader-following control.

[0026] Figure 9C The second embodiment of the present invention is shown and the Figure 8The control unit shown performs leader-follower control.

[0027] Figure 10A Shown Figure 8 FIG. 1 shows an exemplary configuration of a coordinate transformation unit in a continuum robot control system according to a second embodiment of the present invention.

[0028] Figure 10B Shown Figure 8 FIG. 1 shows an exemplary configuration of a coordinate transformation unit in a continuum robot control system according to a second embodiment of the present invention.

[0029] Figure 11A The second embodiment of the present invention is shown and Figure 9C Simulation results in the control response of leader-follower control are shown.

[0030] Figure 11B The second embodiment of the present invention is shown and Figure 9C Simulation results in the control response of leader-follower control are shown.

[0031] Figure 11C The second embodiment of the present invention is shown and Figure 9C Simulation results in the control response of leader-follower control are shown.

[0032] Figure 11D The second embodiment of the present invention is shown and Figure 9C Simulation results in the control response of leader-follower control are shown.

[0033] Figure 11E The second embodiment of the present invention is shown and Figure 9C Simulation results in the control response of leader-follower control are shown.

[0034] Figure 11F The second embodiment of the present invention is shown and Figure 9C Simulation results in the control response of leader-follower control are shown.

[0035] Figure 11G The second embodiment of the present invention is shown and Figure 9C Simulation results in the control response of leader-follower control are shown.

[0036] Figure 12A Shown Figure 9B The simulation results of the control response of the leader follower control are shown as Figures 11A to 11G comparison.

[0037] Figure 12B Shown Figure 9BThe simulation results of the control response of the leader follower control are shown as Figures 11A to 11G comparison.

[0038] Figure 12C Shown Figure 9B The simulation results of the control response of the leader follower control are shown as Figures 11A to 11G comparison.

[0039] Figure 12D Shown Figure 9B The simulation results of the control response of the leader follower control are shown as Figures 11A to 11G comparison.

[0040] Figure 12E Shown Figure 9B The simulation results of the control response of the leader follower control are shown as Figures 11A to 11G comparison.

[0041] Figure 12F Shown Figure 9B The simulation results of the control response of the leader follower control are shown as Figures 11A to 11G comparison.

[0042] Figure 12G Shown Figure 9B The simulation results of the control response of the leader follower control are shown as Figures 11A to 11G comparison.

[0043] Figure 13 An example of a schematic configuration of a continuum robot control system according to a third embodiment of the present invention is shown. DETAILED DESCRIPTION

[0044] Embodiments of the present invention will be described below with reference to the accompanying drawings.

[0045] (First embodiment)

[0046] First, a first embodiment of the present invention will be described.

[0047] Figure 1 An example of a schematic configuration of the continuum robot 100 according to the first embodiment of the present invention is shown. Figure 1 A base 140 and a bendable unit 170 are shown as one configuration of the continuum robot 100 .

[0048] The base 140 is a component that supports the bendable unit 170. The bendable unit 170 is a component that includes a plurality of bending sections that bend when the wire (which is a linear member) is driven. More specifically, Figure 1In the illustrated example, the bendable unit 170 includes three bending sections as the plurality of bending sections, ie, a first bending section 171 , a second bending section 172 , and a third bending section 173 provided from a side adjacent to the base 140 .

[0049] The third bending section 173 is a "distal bending section" located on the distal side of the base 140 (more precisely, a "farthest bending section" located on the farthest side of the base 140) among the plurality of bending sections 171 to 173 provided in the bendable unit 170. The third bending section 173 is a preceding bending section when the continuum robot 100 moves forward. Figure 1 As shown, the third curved section 173 includes a wire guide 1731 and a wire 1732. The wire guide is a fixed member (distal fixed member) located at the farthest side of the base 140 in the third curved section 173. The wire is a linear member (distal linear member) fixed to the wire guide 1731 and driven by an actuator (a driving unit housed inside the base 140). Figure 1 In the illustrated example, the wire 1732 includes three wires, and three actuators each corresponding to one of the three wires are housed inside the base 140 .

[0050] The second bending section 172 and the first bending section 171 are located between the third bending section 173 and the base 140 and serve as "subsequent bending sections" that follow the third bending section 173 (which is the most distal bending section) when the continuum robot 100 moves forward. According to the present embodiment, the second bending section 172 serves as the "first subsequent bending section" and the first bending section 171 serves as the "second subsequent bending section."

[0051] The second curved segment 172 is a curved segment located between the third curved segment 173 (which is a distal curved segment (the most distal curved segment)) and the first curved segment 171 (which is a second subsequent curved segment). Figure 1 As shown, the second curved section 172 includes a wire guide 1721 and a wire 1722. The wire guide is a fixed member (first subsequent fixed member) located at the farthest side of the base 140 in the second curved section 172. The wire is a linear member (first subsequent linear member) fixed to the wire guide 1721 and driven by an actuator (which is a driving unit accommodated inside the base 140). Figure 1 In the illustrated example, the wire 1722 includes three wires, and three actuators (different from the three actuators corresponding to the three wires 1732 ) each corresponding to one of the three wires are housed inside the base 140 .

[0052] The first curved section 171 is a curved section located between the second curved section 172 (which is the first subsequent curved section) and the base 140. Figure 1 As shown, the first curved section 171 includes a wire guide 1711, which is a fixed member (second subsequent fixed member) located at the farthest side of the base 140 in the first curved section 171, and a wire 1712, which is a linear member (second subsequent linear member) fixed to the wire guide 1711 and driven by an actuator (which is a driving unit accommodated inside the base 140). Figure 1 In the example shown, the wire 1712 includes three wires, and three actuators, each corresponding to one of the three wires, are housed inside the base 1722 (three actuators that are different from the three actuators corresponding to the three wires 1732 and different from the three actuators corresponding to the three wires 1722).

[0053] The following describes a coordinate system used as a reference when performing control to bend each of the bending sections 171 to 173 according to the present embodiment.

[0054] In order to control the bending motion of the third bending section 173, a predetermined position on the wire guide 1721 of the second bending section 172 (for example, the position of the center of the surface of the wire guide 1721) is defined as the origin O3, and reference axes x3, y3, and z3 are set with respect to the direction faced by the wire guide 1721. Then, the bending motion is controlled based on the first relative coordinate system 1730, which is a relative coordinate system in which the origin O3 and reference axes x3, y3, and z3 relative to the wire guide 1721 change according to the movement of the continuum robot 100. More specifically, in Figure 1 In the example shown, the reference axes x3 and y3 are set to be orthogonal to each other in the surface direction of the wire guide 1721, and the reference axis z3 is set in a direction orthogonal to the surface of the wire guide 1721 (orthogonal to the reference axes x3 and y3). Figure 1 In the example shown, the bending angle θ-3 of the third bending section 173 and thus the third bending section 173 in the first relative coordinate system 1730 is determined by the angle formed by the reference axis 101-3 corresponding to the reference axis z3 and the direction orthogonal to the surface of the wire guide 1731 (the direction of the reference axis z4), as shown in FIG. Figure 1 shown.

[0055] In order to control the bending motion of the second bending section 172, a predetermined position on the wire guide 1711 of the first bending section 171 (for example, the position of the center of the surface of the wire guide 1711) is defined as the origin O2, and reference axes x2, y2, and z2 are set with respect to the direction facing the wire guide 1711. The bending motion is controlled based on the second relative coordinate system 1720, which is a relative coordinate system in which the origin O2 and the reference axes x2, y2, and z2 relative to the wire guide 1711 change according to the movement of the continuum robot 100.

[0056] More specifically, in Figure 1 In the example shown, the reference axes x2 and y2 are set to be orthogonal to each other in the surface direction of the wire guide 1711, and the reference axis z2 is set in a direction orthogonal to the surface of the wire guide 1711 (orthogonal to the reference axes x2 and y2). Figure 1 As shown, the bending angle θ2 of the second bending section 172 in the second relative coordinate system 1720 is determined by the angle formed by the reference axis 101 - 2 corresponding to the reference axis z2 and the direction orthogonal to the surface of the wire guide 1721 (the direction of the reference axis z3 ).

[0057] In order to control the bending motion of the first bending section 171, a predetermined position on the upper surface 141 of the base 140 (for example, the position of the center of the upper surface 141 of the base 140) is defined as the origin O1, and reference axes x1, y1, and z1 are set with respect to the direction faced by the upper surface 141 of the base 140. The bending motion is controlled based on the third relative coordinate system 1710, which is a relative coordinate system in which the origin O1 and the reference axes x1, y1, and z1 relative to the upper surface 141 of the base 140 change according to the movement of the continuum robot 100. More specifically, in Figure 1 In the example shown, the reference axes x1 and y1 are arranged to be orthogonal to each other in the surface direction of the upper surface 141 of the base 140, and the reference axis z1 is arranged in a direction orthogonal to the upper surface 141 of the base 140 (orthogonal to the reference axes x1 and y1). Figure 1 As shown, the bending angle θ˜1 of the first bending section 171 in the third relative coordinate system 1710 is determined by the angle formed by the reference axis 101 - 1 corresponding to the reference axis z1 and the direction orthogonal to the surface of the wire guide 1711 (the direction of the reference axis z2 ).

[0058] Actuator( Figure 1171 to 173) is provided inside the base 140. In addition to the bending motions performed by the plurality of bending segments 171 to 173 constituting the bendable unit 170, the continuum robot 100 can also realize Figure 1 The movement in the z1 direction (forward and backward) is shown. In this case, Figure 1 The displacement z of the base 140 is shown b , as an indicator of the movement amount of the continuum robot 100 in the z1 direction (for example, the forward movement amount in the case of forward movement). Figure 1 In the figure, the dotted line represents a virtual guide wire that extends a guide wire perpendicular to the reference axis x1 of the proximal curved segment 171 along the shape of each curved segment to the distal end. This guide wire is referred to as the "virtual reference guide wire." The reference axis x of each relative coordinate system 1710 to 1730 is set to be perpendicular to the virtual reference guide wire from the origin O of the relative coordinate system.

[0059] Figure 2 Shown Figure 1 An example of a detailed schematic configuration of the curved section 171 in the schematic configuration of the continuum robot 100 is shown. That is, Figure 2 A detailed schematic configuration of the proximal curved section 171 (the configuration positioned closest to the base 140) is shown. Figure 2 In, with Figure 1 Similar configurations to those shown in FIG are identified by the same reference numerals, and detailed descriptions of these configurations are omitted. Figure 2 In FIG. 1 , the bending angle of the curved section 171 is represented by the symbol θ1, the turning angle of the curved section 171 is represented by the symbol ζ1, and the curvature radius of the curved section 171 (in Figure 2 The line segment corresponding to the connection point O and point w in is represented by the symbol ρ1. Figure 2 , the bending angle θ1 of the bending section 171 is defined in an absolute coordinate system 1713 in which a predetermined position (e.g., a center position) on the upper surface 141 of the base 140 is defined as an origin O, and reference axes x, y, and z are set with respect to the direction facing the upper surface 141 of the base 140. If the direction facing the upper surface 141 of the base 140 is unchanged, then Figure 2 The absolute coordinate system 1713 shown in Figure 1 The third relative coordinate system 1710 shown in FIG. 1 is the same as that shown in FIG.

[0060] like Figure 2 As shown, in the continuum robot 100 , the wires 111 to 113 are fixedly connected to the connection portions 121 to 123 of the wire guide 160 located at the distal end of the curved section 171 , respectively. Figure 2 The wire guide 160 corresponds to Figure 1 The wire guide 1711 in the embodiment of the present invention is provided. Figure 2 The wires 111 to 113 in the Figure 1 The wire 1712 in the base 140 is pushed and pulled by the actuators 131 to 133 installed inside the base 140. Figure 2 The wires 111 to 113 shown are used to control the posture (bending shape) of the bending section 171. The actuator 131 is a driving unit for driving the wire 111, the actuator 132 is a driving unit for driving the wire 112, and the actuator 133 is a driving unit for driving the wire 113. Figure 2 As shown, the continuum robot 100 further includes wire guides 161 to 164 in the curved section 171, which are members for guiding the wires 111 to 113. The wire guides 161 to 164 can be made into accordion-shaped or mesh-shaped continuum members instead of using a technique of discretely arranging a plurality of members. Figure 2 In the example shown, the wire 111 is fixed to the fixing portions 150 to 153 of the wire guides 161 to 164, respectively. Figure 2 , the central axis of the continuum robot 100 is indicated by a dotted line.

[0061] According to the present embodiment, the wires 111 to 113 are respectively referred to as a wire, b wire, and c wire in the counterclockwise direction in the xy plane. More specifically, Figure 2 In the example shown, the wire 111 corresponds to the a-wire, and the driving displacement (driving amount) of the wire 111 in the bending section 171 generated by the push and pull of the actuator 131 is represented by l p1a Indicates. Figure 2 In the example shown, the wire 112 corresponds to the b wire, and the driving displacement (driving amount) of the wire 112 in the bending section 171 generated by the push and pull of the actuator 132 is represented by l p1b In addition, Figure 2 In the example shown, the wire 113 corresponds to the c-wire, and the driving displacement (driving amount) of the wire 113 in the curved section 171 generated by the push and pull of the actuator 133 is represented by l p1c express.

[0062] exist Figure 2 In the example shown, only the detailed schematic construction related to the curved section 171 is shown and described. Figure 2 The detailed schematic structure of the curved section 171 is shown as follows. Figure 1Each of the illustrated bending sections 172 and 173 is configured to include wires corresponding to the wires 111 to 113, actuators corresponding to the actuators 131 to 133, a wire guide corresponding to the wire guide 160 at the distal end, and wire guides corresponding to the wire guides 161 to 164. In summary, the driving displacements (driving amounts) of the wires a to c that drive the n-th bending section are respectively referred to as l pna 、l pnb and l pnc .

[0063] Figure 3 Shown Figure 2 The example of arrangement of three wires 111 to 113 (a wire to c wire) in the xy plane is shown. Figure 3 As shown, Figure 2 The three wires 111 to 113 (wire a to wire c) are arranged on a side with a length of r. s The vertices of an equilateral triangle, and Figure 3 The phase angle ξ shown n It is the angle that determines the arrangement of the wires driving the nth bending segment.

[0064] Figure 4 FIG. 2 shows an example of a schematic configuration of a continuum robot control system 10-1 according to a first embodiment of the present invention. Figure 4 As shown, the continuum robot control system 10 - 1 includes a continuum robot 100 , a control unit 200 , and various input devices 310 to 340 .

[0065] The input device 310 is used to input the target bending angle θ of the most distal bending section in the relative coordinate system to the control unit 200. L More specifically, in Figure 1 In the example shown, the input device 310 inputs the target bending angle θ~3 of the third bending segment 173 in the first relative coordinate system 1730 to the control unit 200 as the target bending angle θ~3 of the most distal bending segment in the first relative coordinate system 1730. L Except for the target bending angle θ of the most distal bending segment in the relative coordinate system, L In addition, the input device 310 can also input the target turning angle ζ of the farthest curved section in the relative coordinate system to the control unit 200. L .

[0066] The input device 320 inputs the target bending angle θ of the subsequent bending section in the relative coordinate system to the control unit 200. F More specifically, in Figure 1In the example shown, the input device 320 inputs the target bending angle θ˜2 of the second bending segment 172 in the second relative coordinate system 1720 to the control unit 200 as the target bending angle θ˜2 of the subsequent bending segment (first subsequent bending segment) in the second relative coordinate system 1720. F In addition, the input device 320 can input the target bending angle θ~1 of the first bending segment 171 in the third relative coordinate system 1710 to the control unit 200 as the target bending angle θ~1 of the second subsequent bending segment in the third relative coordinate system 1710. F .

[0067] The input device 330 is used to input the displacement z of the base 140 in the moving direction (for example, the forward moving direction) of the continuum robot 100 to the control unit 200. b And also controls the base 140 of the continuum robot 100 to move the displacement z in the z direction b device.

[0068] The input device 340 is a device for inputting various types of information to the control unit 200. More specifically, for example, Figure 1 In the example shown, the input device 340 inputs information such as the length l of the third bending segment 173 (which is the most distal bending segment) and the length l of the second bending segment 172 (which is the subsequent bending segment) (the length l of the second bending segment 172 may include the length l of the first bending segment 171) to the control unit 200.

[0069] The control unit 200 is a unit that controls the actions of the continuum robot 100. Figure 4 As shown, the control unit 200 includes a kinematics calculation unit (Kinematics) 220 and a coordinate transformation unit 230 .

[0070] The kinematics calculation unit 220 is a calculation device for calculating the drive displacement (drive amount) of the wire for each bending section in the corresponding relative coordinate system when the wire of the bending section is driven by the actuator (which is a drive unit). More specifically, the kinematics calculation unit 220 calculates the target bending angle θ of the most distal bending section in the relative coordinate system based on the target bending angle θ~ L and the target bending angle θ of the subsequent bending section in the relative coordinate system input from the input device 320 F To calculate the driving displacement (driving amount) l~ of the wire 1732 (which is the distal linear member) in the relative coordinate system pL and the driving displacement (driving amount) l~ of the wire 1722 (which is a subsequent linear member and may include the wire 1712) in the relative coordinate system. pF .exist Figure 4In the relative coordinate system, the driving displacement (driving amount) of the far-side linear member is l~ pL and the subsequent linear component's driving displacement (driving amount) l~ pF It is uniformly expressed as the driving displacement (driving amount) l of the linear member (conductor) in the relative coordinate system. p .

[0071] The coordinate conversion unit 230 is a unit for converting the driving displacement (driving amount) l of the distal linear member in the relative coordinate system obtained by the kinematics calculation unit 220 to pL and the subsequent linear component's driving displacement (driving amount) l~ pF The driving displacement (driving amount) l of the distal linear member is transformed into the absolute coordinate system. pL and the subsequent linear component's driving displacement (driving amount) l pF The conversion device. Figure 4 The driving displacement (driving amount) of the distal linear member in the absolute coordinate system is l pL and the subsequent linear component's driving displacement (driving amount) l pF It is uniformly expressed as the driving displacement (driving amount) l of the linear member (conductor) in the absolute coordinate system p .

[0072] Then, based on the driving displacement (driving amount) l of the distal linear member in the absolute coordinate system obtained by the coordinate conversion unit 230, pL and the subsequent linear component's driving displacement (driving amount) l pF , the control unit 200 controls the corresponding actuator (driving unit of the continuum robot 100). That is, the control unit 200 controls the driving displacement (driving amount) l of the distal linear member based on the absolute coordinate system. pL and the subsequent linear component's driving displacement (driving amount) l pF Controls the bending motion of the distal bending segment (the most distal bending segment) and subsequent bending segments.

[0073] According to this embodiment, all phase angles ξ n = 0. First, the control performed by the control unit 200 in the x1-z1 plane will be described.

[0074] [Modeling]

[0075] In this chapter, the kinematics of the continuum robot 100 in the x1-z1 plane are derived. The symbols used in this chapter are defined as follows:

[0076] l n : the length of the nth bending segment,

[0077] r n: the distance from the wire passing through the wire guide of the nth bending section to the center of the wire guide,

[0078] e: the number of bending segments in the bendable unit 170 of the continuum robot 100,

[0079] θ n : target bending angle of the nth bending segment (at the distal end),

[0080] θ~ n : target bending angle of the nth bending segment (at the distal end) in the relative coordinate system,

[0081] ρn: the curvature radius of the nth curved segment,

[0082] l pn : the driving displacement (driving amount) of the wire in the nth bending section,

[0083] l~ pn : Drive displacement (drive amount) of the wire in the nth bending section in the relative coordinate system, x tn ,z tn : the coordinates of the far end of the nth curved segment, and

[0084] z b : Displacement of base 140.

[0085] Figure 5 and Figure 6 The first embodiment of the present invention is shown, and Figure 1 An example of a kinematic model of the continuum robot 100 is shown. Figure 2 Same, Figure 5 and Figure 6 It is shown based on the absolute coordinate system. Figure 5 In, with Figure 1 and Figure 2 Configurations similar to those shown in are identified by the same reference numerals, and detailed descriptions of these configurations are omitted.

[0086] According to this embodiment, Figure 5 The kinematics of the continuum robot 100 shown with the number of curved segments e is derived based on the following assumptions:

[0087] 1. The wire is deformed only in the x1-z1 plane.

[0088] 2. In each bending section, the wire deforms with a constant curvature.

[0089] 3. The torsional deformation of the wire is not considered.

[0090] 4. The conductor does not deform in the longitudinal direction.

[0091] Let's first discuss the first curved section (corresponding to Figure 1 and Figure 2 The curved section 171 in FIG.

[0092] When the wire a is driven while the wire b and wire c are fixed, the wire drive displacement (drive amount) l p1 The relationship with the (distal end) bending angle θ1 of the first bending section is given by the following expression (1).

[0093] [Formula 1]

[0094]

[0095] Then, the driving displacement (driving amount) l of the wire in the n-th bending section 17n is derived. pn The bending angle θ at the distal end of the n-th bending section 17n is n , where n is greater than or equal to 2. The bending angle θ of the n-th bending segment 17n (at the distal end) in the relative coordinate system is n is defined as follows:

[0096] θ~ n =θ n -θ n-1 ...(2).

[0097] like Figure 5 As shown, the origin O of the nth curved segment 17n n The coordinates of are expressed as (x tn-1 , z tn-1 ), and adopt the n-1 The relative coordinate system x of the direction and its orthogonal direction n -z n Then, relative coordinate system x n -z n The driving displacement (driving amount) of the wire in l~ pn The bending angle θ with the n-th bending section 17n (at the distal end) is n The relationship between is given by the following expression (3).

[0098] [Formula 2]

[0099]

[0100] The driving displacement (driving amount) of the wire in the n-th bending section 17n is l pn is the sum of the driving displacements (driving amounts) of the conductive wires for driving the nth bending section in the relative coordinate system in the first bending section 171 to the (n-1)th bending section, and is given by the following expressions (4) and (5).

[0101] [Formula 3]

[0102]

[0103] It can be seen from the expression that the bending angle θ of the n-th bending section 17n (at the distal end) is n The driving displacement (driving amount) of the wire only pn The angle of the intermediate curved section is determined by the

[0104] Then, the relationship between the (distal end) bending angle of the nth bending segment 17n and the coordinates of its distal end is derived. First, the first bending segment 171 is discussed. The bending angle θ1 of the first bending segment 171 at the distal end is related to the coordinates (x t1 , z t1 ) are represented by the following expressions (6) and (7).

[0105] [Formula 4]

[0106]

[0107] Then, the (distal end) bending angle θ of the n-th bending segment 17n in the relative coordinate system is n With the far end in the relative coordinate system x n -z n The coordinates in (x~ tn , z~ tn ) are represented by the following expressions (8) and (9).

[0108] [Formula 5]

[0109]

[0110] Therefore, by using the rotation transformation matrix, the coordinates of the far end in the absolute coordinate system (x tn , z tn ) is given by the following expression (10).

[0111] [Formula 6]

[0112]

[0113] According to the present embodiment, the target bending angle of each bending section based on the relative coordinate system is provided to the control unit 200. Therefore, the control unit 200 can calculate the driving displacement (driving amount) of the wire in each bending section in the relative coordinate system based on the target bending angle of each bending section in the relative coordinate system by using the relationship described in Expression (3). Figure 4The kinematics calculation unit 220 shown performs calculation processing using expression (3). Then, the control unit 200 can transform the driving displacement (driving amount) of the wire of each bending section in the relative coordinate system obtained using expression (3) into the driving displacement (driving amount) of the wire of the bending section in the absolute coordinate system using expression (4). Figure 4 The coordinate transformation unit 230 shown performs the transformation processing using the expression (4). Then, the control unit 200 can control the shape of the bendable unit 170 of the continuum robot 100 by providing the drive displacement (drive amount) of the wire of each bending section in the absolute coordinate system obtained using the expression (4) as the target drive displacement (target drive amount) to the actuator serving as the drive unit.

[0114] The control unit 200 of the continuum robot control system 10 - 1 according to the first embodiment executes the processing described below.

[0115] The control unit 200 defines a predetermined position on the wire guide 1721 as the origin O3 and sets reference axes x3, y3, and z3 for the direction facing the wire guide 1721, which is a subsequent fixing member (first subsequent fixing member) of the second bending section 172 (which is a subsequent bending section (first subsequent bending section)). Then, the control unit 200 drives the wire 1732 (which is a distal linear member of the third bending section 173) with an actuator serving as a driving unit of the continuum robot 100 based on a relative coordinate system (first relative coordinate system) 1730 (in which the origin O3 and reference axes x3, y3, and z3 related to the wire guide 1721 change according to the movement of the continuum robot 100), so that the third bending section 173 (which is a distal bending section) is bent.

[0116] This configuration enables, for example, an operator to intuitively operate the bendable unit 170 of the continuum robot 100 even when the camera is located at the farthest end of the continuum robot 100 and the operator cannot look down at the continuum robot 100 while observing the camera image. Therefore, the bendable unit 170 of the continuum robot 100 is less likely to come into contact with surrounding obstacles in a narrow space and can easily enter a desired path.

[0117] Furthermore, the control unit 200 of the continuum robot control system 10 - 1 according to the first embodiment executes the processing described below.

[0118] The control unit 200 defines a predetermined position on the wire guide 1711 as an origin O2 and sets reference axes x2, y2, and z2 for the direction facing the wire guide 1711. The wire guide is a subsequent fixing member (which is a second subsequent fixing member) of the first bending section 171. The subsequent fixing member is the second subsequent fixing member. Then, based on the second relative coordinate system 1720 (in which the origin O2 and reference axes x2, y2, and z2 associated with the wire guide 1711 change according to the movement of the continuum robot 100), the control unit 200 drives the wire 1722 (which is the first subsequent linear member of the second bending section 172) with an actuator serving as a driving unit of the continuum robot 100, so that the second bending section 172 (which is the first subsequent bending section) bends following the bending action of the third bending section 173 (which is the distal bending section).

[0119] This configuration enables, for example, an operator to perform intuitive operations even when a camera is set at the farthest end of the continuum robot 100 and an operator who cannot look down at the continuum robot 100 operates the bendable unit 170 of the continuum robot 100 while observing the camera image.

[0120] The control unit 200 of the continuum robot control system 10 - 1 according to the first embodiment further includes a kinematics calculation unit 220 and a coordinate transformation unit 230 that perform the processing described below.

[0121] The kinematics calculation unit 220 calculates the target bending angle θ of the distal bending segment (the most distal bending segment) input in the relative coordinate system. L and the target bending angle θ of the subsequent bending section input F To calculate the driving displacement (driving amount) l~ of the wire 1732 (which is the distal linear member) in the relative coordinate system pL and the driving displacement (driving amount) of the wire 1722 (which is a subsequent linear member) (and may include the wire 1712) l~ pF .

[0122] The coordinate conversion unit 230 converts the driving displacement (driving amount) l of the distal linear member in the relative coordinate system obtained by the kinematics calculation unit 220 to pL and the subsequent linear component's driving displacement (driving amount) l~ pF The driving displacement (driving amount) l of the distal linear member is transformed into the absolute coordinate system. pL and the subsequent linear component's driving displacement (driving amount) l pF According to this embodiment, when obtaining the driving displacement (driving amount) l of the distal linear member in the absolute coordinate system, pLWhen the coordinate transformation unit 230 uses the expression (4) to transform the driving displacement (driving amount) l of the subsequent linear member to pF The driving displacement (driving amount) l~ added to the distal linear member in the relative coordinate system obtained by the kinematics calculation unit 220 pL When obtaining the driving displacement (driving amount) l of the subsequent linear component in the absolute coordinate system pF When , the coordinate transformation unit 230 can also perform similar addition using Expression (4).

[0123] Then, the control unit 200 calculates the driving displacement (driving amount) of the distal linear member based on the driving displacement (driving amount) l in the absolute coordinate system obtained by the coordinate conversion unit 230. pL and the subsequent linear component's driving displacement (driving amount) l pF The respective actuators serving as driving units of the continuum robot 100 are controlled.

[0124] The first embodiment also includes a processing method (continuum robot control method) executed by the continuum robot control system 10 - 1 .

[0125] (Second embodiment)

[0126] In the following description of the second embodiment, the description of the same matters as those of the first embodiment is omitted, and matters different from those described above in the first embodiment are described.

[0127] According to the second embodiment, a leader-following control system is designed based on the control using the relative coordinate system described in the above-mentioned first embodiment.

[0128] Figure 7 FIG. 2 shows an example of leader following control of the continuum robot 100 according to the second embodiment of the present invention. Figure 7 In, with Figure 1 and Figure 2 Similar structures to those shown in FIG are identified by the same reference numerals. Figure 1 The z shown b The direction is Figure 7 In the direction from bottom to top. In addition, Figure 7 , a target path 710 along which the continuum robot 100 including the base 140 and the bendable unit 170 moves is indicated by a dotted line.

[0129] As used herein, the term “leader following control” refers to a method for controlling subsequent bending segments to move along the same path (target path 710) as the path along which the distalmost bending segment of the bendable unit 170 moves. Figure 7 shown.

[0130] exist Figure 7 In FIG. 7 , time point 701 represents an initial state in which the bendable unit 170 extends from the upper surface of the base 140 in the z direction without being bent. Figure 7 As shown, as time passes from time point 702 to time point 703, to time point 704, and then to time point 705, the base 140 moves in the z-direction and the bendable unit 170 is bending.

[0131] This leader-following control enables the continuum robot 100 to glide through narrow spaces. Leader-following control does not require pre-defining the target path 710. For example, the bending angle of the distal-most curved segment can be continuously propagated to the bending angles of subsequent curved segments along the length of that curved segment. This method allows the operator to perform leader-following control of the continuum robot 100 in real time by providing instructions using a joystick or the like regarding only the bending angle of the distal-most curved segment and the displacement (advancement) of the base 140.

[0132] Figure 8 FIG. 2 shows an example of a schematic configuration of a continuum robot control system 10-2 according to a second embodiment of the present invention. Figure 8 In, with Figure 4 Configurations similar to those shown in are identified by the same reference numerals, and detailed descriptions of these configurations are omitted.

[0133] like Figure 8 As shown, the continuum robot control system 10 - 2 includes a continuum robot 100 , a control unit 200 , and various input devices 310 , 330 , and 340 .

[0134] The control unit 200 is a unit that controls the actions of the continuum robot 100. Figure 8 As shown, the control unit 200 includes an angle calculation unit 210, a kinematics calculation unit 220, and a coordinate transformation unit 230. That is, Figure 8 The control unit 200 according to the second embodiment shown includes Figure 4 The control unit 200 according to the first embodiment shown has an angle calculation unit 210 additionally provided in its configuration.

[0135] The angle calculation unit 210 is used to calculate the target bending angle θ of the most distal bending segment in the relative coordinate system based on the input from the input device 310. L , the displacement z of the base 140 input from the input device 330 b The target bending angle θ of the most distal bending segment in the relative coordinate system is calculated based on the length l of the subsequent bending segment input from the input device 340.L The target bending angle θ of the subsequent bending section in the relative coordinate system is changed. F Computing device. Figure 8 As shown in FIG, the angle calculation unit 210 includes a storage unit 211, a reference table rewriting unit 212, and an information input unit 213. The storage unit 211 is a storage device for storing a plurality of different reference tables 2111, each of which represents a target bending angle θ of a pair of distalmost bending segments in a relative coordinate system, and various information required for the processing performed by the angle calculation unit 210. L and the target bending angle θ of the subsequent bending section F Displacement z from base 140 b The information input unit 213 is an information input device for inputting information related to the length l of the bending segment and information specifying the reference table 2111 to be used, which is input from the input device 340, to the reference table rewriting unit 212. The reference table rewriting unit 212 selects one reference table 2111 to be used from the plurality of reference tables 2111 stored in the storage unit 211 based on the information input from the information input unit 213, and selects the reference table 2111 to be used according to the target bending angle θ of the most distal bending segment in the relative coordinate system. L and the displacement z of the base 140 b Changes rewrite the selected reference table 2111.

[0136] Then, the kinematics calculation unit 220 calculates the target bending angles θ and θ of the distalmost bending segment in the relative coordinate system based on the target bending angles θ and θ of the distalmost bending segment input from the input device 310. L and the target bending angle θ of the subsequent bending section in the relative coordinate system calculated and output by the angle calculation unit 210. F Calculate the driving displacement (driving amount) l~ of the wire 1732 (which is the distal linear member) in the relative coordinate system. pL and the driving displacement (driving amount) l~ of the wire 1722 (which is the subsequent linear member) (and may include the wire 1712) in the relative coordinate system. pF .exist Figure 8 In, such as Figure 4 Similarly, the driving displacement (driving amount) of the far-side linear member in the relative coordinate system is l~ pL and the subsequent linear component's driving displacement (driving amount) l~ pF It is uniformly expressed as the driving displacement (driving amount) l of the linear member (conductor) in the relative coordinate system. p .

[0137] 1) Control system design

[0138] 1.1) Leader-Follower Control

[0139] Figures 9A to 9C The second embodiment of the present invention is shown and the Figure 8 The control unit 200 shown in FIG. 1 performs leader-following control.

[0140] Figure 9A is a graph in which the abscissa axis represents the displacement z of the base 140 b , while the ordinate axis represents the bending angle θ in the absolute coordinate system. Figure 9A In FIG, the dotted line represents the bending angle instruction (target bending angle) from the operator for the most distal bending segment (leader), and the thick dotted line represents the bending angle instruction (target bending angle) for the subsequent bending segment (follower). Figure 9A In the embodiment, if the operator gives a bending angle instruction ab for the most distal bending section at the displacement a of the base 140, the bending angle of the subsequent bending section can be automatically generated as, for example, cd at the displacement c of the base 140. In this case, the displacement c of the base 140 is determined so that the distance ac is, for example, the length l of the subsequent bending section. Then, the bending angle instruction for the subsequent bending section is stored in the storage unit 211 of the control unit 200 and is automatically generated according to the displacement z of the base 140. b The bending angle command is read out. If the number of bending sections of the bendable unit 170 is three or more, the subsequent bending section is replaced with the most distal bending section, and the process is continuously performed. Therefore, the bending angle command for all the bending sections can be obtained.

[0141] However, in the case of such a bending angle instruction, when the displacement Z of the base 140 b When the bending angle of the subsequent bending section is between point a and point c, the bending angle of the subsequent bending section does not change, and the bending angle instruction for the subsequent bending section increases at the displacement c of the base 140, causing the movement of the continuum robot 100 to change abruptly. Therefore, the bending angle instruction of the subsequent bending section can be interpolated to connect Figure 9A Points a and d are shown.

[0142] However, when the length of the subsequent bending section is greater than the length of the most distal bending section, the base 140 moves forward with the bending angle of the subsequent bending section being shallow. Therefore, the bendable unit 170 is likely to come into contact with surrounding obstacles. Figure 9A As shown, the displacement e of the base 140 that causes the bending angle of the subsequent bending section to rise is determined so that the distance ae is smaller than the actual length l of the subsequent bending section, and the distance ae is set as the virtual length of the subsequent bending section.

[0143] Therefore, an instruction is made so that the bending angle of the subsequent bending section is closer to the bending angle of the most distal bending section, which helps to enter a narrow space path. According to Patent Document 1, in order to perform the interpolation method, Figure 9A The hatched right triangle in FIG is a right triangle, wherein the length of the base of the right triangle is set to the virtual length of the subsequent bending section, the height is the distance ab, and the base of the right triangle coincides with the line segment ae. In addition, according to Patent Document 1, the displacement z of the base 140 is b At each point from point a to point e, the displacement z of the base 140 is obtained b The intersection of the straight line orthogonal to the coordinate axis and the hypotenuse of the right triangle is obtained, and the length from the intersection to the base of the right triangle is added to the bending angle instruction of the subsequent bending section indicated by the thick dotted line. Thus, the target bending angle is generated by interpolation. Figure 9A In FIG, the solid line represents the target bending angle of the subsequent bending segment after interpolation.

[0144] exist Figure 9A In the leader-following control using the virtual length of the subsequent bending section in the absolute coordinate system, when the base 140 moves forward beyond the displacement e of the base 140, the bending angle ab of the distalmost bending section remains unchanged. This allows, for example, insertion into a narrow space without changing the operator's bending angle command. However, if this control algorithm is applied directly to the relative coordinate system, the response will be different from that in the absolute coordinate system. Figure 9B Describe this phenomenon.

[0145] Figure 9B is a graph in which the horizontal axis is the displacement z of the base 140 b , and the vertical axis is the bending angle θ~ in the relative coordinate system. Figure 9B In FIG, the dotted line represents the bending angle instruction (target bending angle) of the most distal bending segment (leader) from the operator, and the solid line represents the bending angle instruction (target bending angle) of the subsequent bending segment (follower) after interpolation. Figure 9B When the operator gives the bending angle instruction ab for the distalmost bending section at the displacement a of the base 140, the bending angle is automatically generated for the subsequent bending sections, for example, so that the bending angle is ef at the displacement e of the base 140. Figure 9BAt the displacement e of the base 140 shown, the operator's bend angle command for the farthest bend segment is fully propagated to the subsequent bend segments, so that in the relative coordinate system, the operator assigns a bend angle command of 0 to the farthest bend segment to maintain the initial movement direction. Since the bend angle command propagates to the subsequent bend segments over their virtual lengths, the bend angle command for the subsequent bend segments is interpolated to 0 at the displacement g of the base 140. The continuum robot 100 then maintains a completely straight posture during forward movement following the displacement g of the base 140.

[0146] Therefore, this embodiment provides a leader-following control algorithm that enables operability when using a bending angle instruction based on a relative coordinate system to be similar to that in an absolute coordinate system. The subsequent bending section is divided into multiple virtual bending sections (hereinafter referred to as "virtual bending sections"). Assume that nv is the length of the virtual bending section used when dividing the n-th bending section (which is the subsequent bending section). Then, the number of divisions d is given by the following expression (11).

[0147] [Formula 7]

[0148]

[0149] According to this embodiment, the virtual bending segments obtained by virtually dividing the subsequent bending segments are referred to as the first (1st virtual follower), ..., mth, ..., and dth virtual bending segments in order from the virtual bending segment at the distal end. The angle calculation unit 210 propagates the bending angle of the distalmost bending segment in the same manner as the leader-following control in the absolute coordinate system. In addition, the angle calculation unit 210 superimposes all the bending angle commands of the divided multiple virtual bending segments to generate bending angle commands (target bending angles) θ~ for the subsequent bending segments. F .

[0150] Figure 9C 2 shows the processing performed by the angle calculation unit 210 according to the present embodiment.

[0151] like Figure 9B Same, Figure 9C is a graph in which the abscissa axis represents the displacement z of the base 140 b , and the vertical axis represents the bending angle θ~ in the relative coordinate system. Figure 9C, the dotted line represents the bending angle instruction (target bending angle) from the operator for the most distal bending segment (leader), and the thin solid line, the dot-dash line, and the double-dot-dash line represent the bending angle instructions (target bending angles) for the first virtual bending segment (1st virtual follower), the second virtual bending segment (2nd virtual follower), and the third virtual bending segment (3rd virtual follower) in the subsequent bending segments. Figure 9C In the figure, the thick solid line represents the bending angle instruction (target bending angle) θ for the subsequent bending section. F .

[0152] exist Figure 9C , when the operator gives a bending angle instruction ab for the most distal bending segment at the displacement a of the base 140, a bending angle is automatically generated for the first virtual bending segment in the subsequent bending segments so that the bending angle is ef at the displacement e of the base 140 and is 0 at the displacement g of the base 140. Similarly, for the second virtual bending segment in the subsequent bending segments, the bending angle is automatically generated to be gh at the displacement g of the base 140 and is 0 at the displacement c of the base 140. For the third virtual bending segment in the subsequent bending segments, the bending angle is automatically generated to be cd at the displacement c of the base 140 and is 0 at the displacement i of the base 140.

[0153] Then, in Figure 9C , the angle calculation unit 210 superimposes the bending angles of all virtual bending sections (first to third virtual bending sections) in the subsequent bending section, and therefore, for the displacement z from point e to point c of the base 140 b , maintain the bending instruction angle ab as the bending angle instruction (target bending angle) θ for the subsequent bending section F This is consistent with Figure 9A The bending angle instructions for the subsequent bending sections shown in FIG are the same. It can be seen that by using the virtual bending section, the leader following control based on the relative coordinate system can have the same operability as the leader following control using the absolute coordinate system.

[0154] 1.2) Calculation of wire drive displacement (drive amount)

[0155] According to this embodiment, a bending angle instruction (target bending angle) θ~ is provided to the most distal bending section based on the relative coordinate system. L, and the bending angle of the subsequent bending section is propagated in the relative coordinate system. Therefore, in order to obtain the driving displacement (driving amount) of the wire, first, the driving displacement (driving amount) of the wire can be obtained for each bending section in the relative coordinate system by using expression (3), and then the result can be converted into the driving displacement (driving amount) of the wire in the absolute coordinate system by using expression (4). Then, by providing the driving displacement (driving amount) of the wire in the absolute coordinate system as the target driving displacement (target driving amount) of the driving unit, the shape of the bendable unit 170 of the continuum robot 100 can be controlled.

[0156] Figure 10A and Figure 10B Shown Figure 8 The example configuration of the coordinate transformation unit 230 of the continuum robot control system 10-2 according to the second embodiment of the present invention is shown. Figure 10A and Figure 10B In, with Figure 8 Similar configurations to those shown in FIG are identified by the same reference numerals, and detailed descriptions of these configurations are omitted. More specifically, Figure 10A shows a first configuration example of the coordinate transformation unit 230 according to the second embodiment, and Figure 10B A second configuration example of the coordinate transformation unit 230 according to the second embodiment is shown.

[0157] exist Figure 10A and Figure 10B In FIG, FTL represents the angle calculation unit 210, which corresponds to the algorithm part of the leader following control in the relative coordinate system. Figure 10A and Figure 10B The symbols l~ pL Indicates the drive displacement (drive amount) of the wire in the farthest curved section in the relative coordinate system. Figure 10A The symbols l~ pF and Figure 10B The symbols l~ pn To l~ p1 Indicates the driving displacement (driving amount) of the wire in the subsequent position bending section in the relative coordinate system. Figure 10A and Figure 10B The coordinate conversion unit 230 shown in φ converts the drive displacement (drive amount) of the wire in the relative coordinate system into the drive displacement (drive amount) of the wire in the absolute coordinate system by using Expression (4).

[0158] Figure 10A The algorithm is shown in relation to two bending segments: the most distal bending segment and the subsequent position bending segment. Figure 10B A more general algorithm is shown, where the number of curved segments is L (L is a positive number, e.g., greater than or equal to three). Figure 10B In the relative coordinate system, the bending angle instruction (target bending angle) θ of the farthest bending section is L The angle calculation unit 210 propagates to the first bending section, and the drive displacement (drive amount) of the wire in each bending section in the relative coordinate system is calculated by the kinematics calculation unit 220. Then, in the coordinate transformation unit 230 surrounded by the dotted line, the drive displacement (drive amount) of the wire in the n-th bending section in the absolute coordinate system is calculated using, for example, Expression (4).

[0159] 2) Simulation

[0160] In this chapter, the leader-following control system in the relative coordinate system described in the previous chapter is used for simulation. In this simulation, the number of bending segments of the bendable unit 170 is three (i.e., the bendable unit 170 consists of the first bending segment 171 to the third bending segment 173, as shown in FIG. Figure 1 ). In addition, the simulation was performed on a continuum robot 100 including a first curved section 171 having a length of 0.04 m, a second curved section 172 having a length of 0.01 m, and a third curved section 173 having a length of 0.01 m. The first curved section 171 (which is a subsequent curved section) was divided into four virtual curved sections, each having a length of 0.01 m.

[0161] Figures 11A to 11G A second embodiment of the present invention is shown, and Figure 9C The simulation results of the control response of the leader follower control are shown. More specifically, Figures 11A to 11G The simulation results are shown in Figures 11A to 11G In, with Figure 1 Similar configurations to those shown in FIG. 1 are identified by the same reference numerals.

[0162] exist Figures 11A to 11G In the simulation shown in , the bending operation for the third bending segment 173 (which is the most distal bending segment) includes moving the third bending segment 173 straight forward 0.01 m after the start of the action, bending the third bending segment 173 at a bending angle of 45 degrees, and further moving the third bending segment 173 forward 0.05 m.

[0163] exist Figures 11A to 11G In FIG. 1 , a square mark indicates the base 140 , a solid line indicates the first bending section 171 , a dashed line indicates the second bending section 172 , and a dashed line indicates the third bending section 173 . Figures 11A to 11G , the dotted line represents the assumed path 1110 .

[0164] More specifically, in Figure 11BIn FIG. 1 , the operator issues a bending angle instruction to the third bending section 173 (which is the most distal bending section) to bend at 45 degrees. Figure 11C , the bending angle instruction from the operator is propagated to the second bending segment 172 (which is the first subsequent bending segment), and the second bending segment 172 is bent at 45 degrees. Then, the operator operates the third bending segment 173 (which is the most distal bending segment) to bend at 0 degrees based on the relative coordinate system and maintain the movement direction.

[0165] Later, in Figure 11D , the bending angle instruction from the operator is propagated to the first bending segment 171 (which is the second subsequent bending segment), and the first bending segment 171 is bent at 45 degrees. At this time, the bending angle instruction of 0 degrees based on the relative coordinate system is propagated to the second bending segment 172. Since the length of each virtual bending segment in the first bending segment 171 is set to 0.01m, the "45 degrees" specified by the initial bending angle instruction from the operator is propagated to the first virtual bending segment. The bending angles of the second to fourth virtual bending segments in the first bending segment 171 are 0 degrees. According to the present embodiment, since all the bending angle instructions of the virtual bending segments are superimposed to generate the bending angle instruction (target bending angle) for the first bending segment 171 in the relative coordinate system, the first bending segment 171 is bent at 45 degrees. This is the same response as the response when the virtual segment length is set to 0.01 in Patent Document 1.

[0166] Later, in Figures 11E to 11G , the bending angle instruction of 45 degrees (which is the initial bending angle instruction from the operator) is propagated to the second to fourth virtual bending sections in the first bending section 171, respectively, and the bending angles of the bending sections including the other virtual bending sections are 0 degrees. Figures 11E to 11G In each of the figures, the bending angle of the first bending section 171 is 45 degrees. Figure 11B , while moving the base 140 forward while executing the bending angle instruction for the third bending segment 173 specified in . This enables the operator to intuitively operate the bendable unit 170 using a relative coordinate system based on the second bending segment 172 when, for example, the operator uses a camera mounted on the front end of the continuum robot (for example, the front end (farthest end) of the third bending segment 173). In addition, according to the present embodiment, the maintenance of the bending angle instruction during the forward movement, which is achieved by using a virtual segment length in the absolute coordinate system, is achieved in the relative coordinate system. Therefore, for example, if Figures 11A to 11G The assumed path 1110 indicated by the dotted line in FIG. 1 is a narrow space having a certain width, and the continuum robot 100 can enter the narrow space along the shape of the narrow space.

[0167] Figures 12A to 12G Shown with Figures 11A to 11G Comparative Figure 9B The simulation results of the control response of the leader follower control are shown. More specifically, as a comparative example, Figures 12A to 12G Shown when not in use Figure 9B The simulation results of the control response of the leader-following control in the case of a virtual curved section are shown in FIG. Figures 12A to 12G In, with Figure 1 and Figures 11A to 11G Similar configurations to those shown in FIG. 1 are identified by the same reference numerals.

[0168] 12A to 12D Shown with the above 11A to 11D Same response as in the response.

[0169] However, in Figures 12E to 12G In the example, the bending angle instruction of 0 degrees is propagated to the first bending section 171. This is because Figure 12C , the bending angle instruction provided to the third bending section 173 (which is the most distal bending section) is propagated. Therefore, it can be seen that the bending angle of the first bending section 171 is restored to 0 degrees, and therefore, the bending angle instruction provided by the operator in Figure 12B The base 140 is moved forward while the bending angle instruction of the third bending section 173 specified in the embodiment is set. For example, if Figures 12A to 12G If the assumed path 1110 indicated by the dotted line is a narrow space having a certain width, the front end of the bendable unit 170 of the continuum robot 100 enters the narrow space while contacting the wall of the narrow space at an angle of 45 degrees, which may damage the continuum robot 100.

[0170] The control unit 200 of the continuum robot control system 10 - 2 according to the second embodiment includes an angle calculation unit 210 that performs the processing described below.

[0171] When calculating the target bending angle θ of the subsequent bending section in the relative coordinate system, F When the following bending segment is bent, the angle calculation unit 210 divides the subsequent bending segment into a plurality of segments (virtual bending segments), and performs a process of superimposing the target bending angles of the plurality of virtual bending segments in the relative coordinate system when the subsequent bending segment is bent following the bending action of the distal bending segment (for example, referring to Figure 9C ).

[0172] This configuration enables the bendable unit 170 to enter a narrow space along the narrow space when the bendable unit 170 of the continuum robot 100 enters the narrow space.

[0173] (Third embodiment)

[0174] In the description of the third embodiment described below, the description of the same matters as the first and second embodiments described above is omitted, and matters different from those described above in the first and second embodiments are described.

[0175] According to the first and second embodiments, the motion control of the continuum robot 100 in the xz plane is described. According to the third embodiment, the motion control of the continuum robot 100 based on the relative coordinate system in the three-dimensional space is described.

[0176] In order to obtain the driving displacement generated by the actuator for controlling the bending angle and the turning angle of the continuum robot 100 , kinematic derivation is performed.

[0177] The symbols used in this embodiment are defined as follows:

[0178] l nd : the length of the central axis of the nth bending segment,

[0179] θ n : target bending angle of (the distal end of) the nth bending segment,

[0180] ζ n : target steering angle of (the far end of) the nth curved segment,

[0181] θ~ n : target bending angle of (the distal end of) the nth bending segment in the relative coordinate system,

[0182] ζ~ n : the target steering angle of (the far end of) the nth bending segment in the relative coordinate system, and

[0183] ρn: The curvature radius of the nth curved segment.

[0184] In addition, according to the present embodiment, the sign for the driving displacement (driving amount) of the wire is defined as follows:

[0185] l~ pnam 、l~ pnbm 、l~ pncm : The driving displacement (driving amount) of the a-wire, b-wire and c-wire connected to the distal end of the n-th bending segment in the relative coordinate system xm-ym-zm in the m-th bending segment.

[0186] Here, n≥m.

[0187] According to the present embodiment, the following assumptions are then made to derive the kinematics of the continuum robot 100:

[0188] 1. In each bending section, the wire deforms with a constant curvature.

[0189] 2. The torsional deformation of the wire is not considered.

[0190] 3. The conductor does not deform in the longitudinal direction.

[0191] 4. The friction between the wire guide and the wire is not considered.

[0192] According to this embodiment, the rotation matrices around the reference axis z and the reference axis y are represented as R z (θ) and R y (θ), which is given by the following expression (12).

[0193] [Formula 8]

[0194]

[0195] The first curved section 171 is discussed first.

[0196] In the first bending section 171, the corresponding driving displacements (driving amounts) of the wires a to c are l to p1a1 、l~ p1b1 and l~ p1c1 The relationship between the bending angle θ˜1 and the turning angle ζ˜1 at its distal end is given by the following expression (13).

[0197] [Formula 9]

[0198]

[0199] Then, the corresponding driving displacement (driving amount) l of the wire a to the wire c in the n-th bending section of the continuum robot 100 having a plurality of bending sections is obtained. pna 、l pnb and l pnc The bending angle θ at the distal end n and steering angle ζ~ n First, let e denote the number of curved segments, and let ξ n represents the phase angle of the wire driving the nth bending segment. Then, the phase angle ξ n It is given by the following expression (14).

[0200] [Formula 10]

[0201]

[0202] Therefore, the driving displacement (driving amount) from wire a to wire c in the relative coordinate system xm-ym-zm is l~ pnam 、l~ pnbm and l~ pncmIt is given by the following expression (15).

[0203] [Formula 11]

[0204]

[0205] Therefore, the driving displacement (driving amount) of the wire a to the wire c in the n-th bending section is l pna 、l pnb and l pnc Each of is the sum of the drive displacements (drive amounts) of the a-wire to the c-wire in the first to n-th bends in the relative coordinate system, and is given by the following Expression (16).

[0206] [Formula 12]

[0207]

[0208] The driving displacement (driving amount) of the wire a to the wire c can be obtained by using expression (15) to obtain the driving displacement (driving amount) of the wire in each bending segment in the relative coordinate system and then by using expression (16) to transform the driving displacement (driving amount) of the wire into the driving displacement (driving amount) in the absolute coordinate system.

[0209] Then, the relationship among the coordinate transformation matrix obtained by the transformation, the bending angle and the steering angle of the n-th bending section (at the distal end), and the coordinates of the distal end of the n-th bending section is derived.

[0210] The coordinates of the far end of the nth curved segment in the relative coordinate system xm-ym-zm (x~ tn ,y~ tn , z~ tn ) are given by the following expressions (17), (18) and (19) respectively.

[0211] [Formula 13]

[0212]

[0213] Therefore, by using the rotation transformation matrix, the coordinates (x tn ,y tn , z tn ) is given by the following expression (20).

[0214] [Formula 14]

[0215]

[0216] Figure 13FIG. 1 shows an example of a schematic configuration of a continuum robot control system 10-3 according to a third embodiment of the present invention. Figure 13 In, with Figure 8 as well as Figure 10A and Figure 10B Configurations similar to those shown in are identified by the same reference numerals, and detailed descriptions of these configurations are omitted.

[0217] like Figure 13 As shown, the continuum robot control system 10 - 3 includes a continuum robot 100 , a control unit 200 , and various input devices 310 and 330 to 350 .

[0218] The input device 350 is used to drive the phase angles ξ1 to ξ L The devices are input to the control unit 200 respectively.

[0219] According to this embodiment, the input device 310 is used to input the target bending angle θ of the most distal bending segment in the relative coordinate system. L and target steering angle ζ~ L Input to the device of the control unit 200.

[0220] The target steering angle ζ of the subsequent bending section in the relative coordinate system is obtained by replacing the in-plane bending angle in the leader following control according to the first embodiment with the steering angle. F At this time, the virtual bending section can be used to provide the same maneuverability as that in leader-following control using an absolute coordinate system.

[0221] In addition, the angle of each bending section can be controlled by obtaining the driving displacement (driving amount) of the wire for each bending section in the relative coordinate system using expression (15) and converting the driving displacement (driving amount) of the wire into the driving displacement (driving amount) in the absolute coordinate system using expression (16).

[0222] like Figure 13 As shown, the kinematics calculation unit 220 according to the third embodiment includes a plurality of "Loc.Kine." blocks 221. The "Loc.Kine." block 221 receives the target bending angles θ to θ of the n-th bending segment in the relative coordinate system. n and target steering angle ζ~ n and the phase angle ξ of the wire driving the nth bending segment n , and output the driving displacement (driving amount) l of the wire in the relative coordinate system pnam 、l~ pnbm and l~ pncm .exist Figure 13 In the example, we use vector representation to represent l~pnam 、l~ pnbm and l~ pncm Unified expression is l~ pnxm .

[0223] The coordinate transformation unit 230 according to the third embodiment calculates the sum of the drive displacements (drive amounts) of the wires in the relative displacement system as expressed by Expression (16). Therefore, the drive displacement (drive amount) l of the wires in the n-th bending section can be obtained. pna 、l pnb and l pnc .exist Figure 13 In the vector representation, l pna 、l pnb and l pnc Unified as l pnx .

[0224] As in the first embodiment, according to the third embodiment, even in a case where, for example, a camera is set at the farthest end of the continuum robot 100 and the operator who cannot look down at the continuum robot 100 operates the flexible unit 170 of the continuum robot 100 while observing the camera image, the operator can intuitively operate the flexible unit 170 of the continuum robot 100.

[0225] (Other embodiments)

[0226] The present invention may also be implemented by providing a program that provides one or more functions of the above-described embodiments to a system or device via a network or storage medium and causing one or more processors of the system or device to execute the program. Alternatively, the present invention may also be implemented by a circuit (e.g., ASIC) that implements one or more functions.

[0227] The program and the computer-readable storage medium storing the program are included in the present invention.

[0228] The above-described embodiments of the present invention are merely examples of embodiments for implementing the present invention, and the technical scope of the present invention should not be interpreted as being limited by the embodiments. That is, the present invention can be implemented in various forms without departing from the technical concept of the present invention or its main features.

[0229] The present invention is not limited to the above embodiments, and various changes and modifications can be made without departing from the spirit and scope of the present invention. Therefore, the following claims are attached to disclose the scope of the present invention.

[0230] This application claims the benefit of Japanese Patent Application No. 2022-020491, filed February 14, 2022, which is hereby incorporated by reference herein in its entirety.

[0231] Reference Signs List

[0232] 100 Continuum Robot

[0233] 140 base

[0234] 141 Upper surface of base

[0235] 170 bendable units

[0236] 171 First bending section

[0237] 1710 The third relative coordinate system

[0238] 1711 Wire Guide

[0239] 1712 Wire

[0240] 172 Second bending section

[0241] 1720 Second relative coordinate system

[0242] 1721 Wire Guide

[0243] 1722 Wire

[0244] 173 Third bending section

[0245] 1730 First relative coordinate system

[0246] 1731 Wire Guide

[0247] 1732 Wire

Claims

1. A continuum robot control system comprising: A continuum robot, comprising: a bendable unit having a plurality of bending segments, each of the plurality of bending segments being configured to be bent by a driven linear member; a base configured to support the bendable unit; and a driving unit configured to drive the linear member, wherein the plurality of bending segments of the bendable unit include a distal bending segment and a subsequent bending segment, the distal bending segment being located distal to the base and including a distal fixing member located distal most of the base in the distal bending segment and a distal linear member serving as a linear member fixed to the distal fixing member and driven by the driving unit, the subsequent bending segment being located between the distal bending segment and the base and including a subsequent fixing member located distal most of the base in the subsequent bending segment and a subsequent linear member serving as a linear member fixed to the subsequent fixing member and driven by the driving unit; and a control unit configured to control the motion of the continuum robot, wherein the control unit defines a predetermined position on the subsequent fixing member as an origin, sets a reference axis for the direction faced by the subsequent fixing member, and causes the drive unit to drive the distal linear member so as to bend the distal bending section based on a relative coordinate system, in which the origin and the reference axis associated with the subsequent fixing member change according to the movement of the continuum robot.

2. The continuum robot control system according to claim 1, wherein: The subsequent bending section includes a first subsequent bending section and a second subsequent bending section, wherein the first subsequent bending section is located between the distal bending section and the second subsequent bending section and includes a first subsequent fixing member and a first subsequent linear member, the first subsequent fixing member being located at the distalmost side of the base in the first subsequent bending section, the first subsequent linear member being a linear member fixed to the first subsequent fixing member and driven by the driving unit, wherein the second subsequent bending section is located between the first subsequent bending section and the base, and includes a second subsequent fixing member and a second subsequent linear member, the second subsequent fixing member being located at the farthest side of the base in the second subsequent bending section, the second subsequent linear member serving as a linear member fixed to the second subsequent fixing member and driven by the driving unit, wherein the control unit defines the predetermined position on the first subsequent fixing member as an origin, sets a reference axis for a direction faced by the first subsequent fixing member, and causes the driving unit to drive the distal linear member so as to bend the distal bending section based on a first relative coordinate system serving as a relative coordinate system in which an origin and a reference axis associated with the first subsequent fixing member change according to movement of the continuum robot, and wherein the control unit defines the predetermined position on the second subsequent fixing member as an origin, sets a reference axis for the direction faced by the second subsequent fixing member, and causes the driving unit to drive the first subsequent linear member so as to bend the first subsequent bending section following the bending action of the distal bending section based on a second relative coordinate system, wherein the second relative coordinate system serves as such a relative coordinate system, wherein the origin and the reference axis associated with the second subsequent fixing member change according to the movement of the continuum robot.

3. The continuum robot control system according to claim 1 or 2, wherein: The control unit includes a kinematics calculation unit configured to calculate a driving amount of the distal linear member and a driving amount of the subsequent linear member in the relative coordinate system based on an input target bending angle of the distal bending section and an input target bending angle of the subsequent bending section in the relative coordinate system, and a coordinate transformation unit configured to transform the driving amount of the distal linear member and the driving amount of the subsequent linear member in the relative coordinate system obtained by the kinematics calculation unit into the driving amount of the distal linear member and the driving amount of the subsequent linear member in the absolute coordinate system, and wherein the control unit controls the driving unit based on the driving amount of the distal linear member and the driving amount of the subsequent linear member in the absolute coordinate system obtained by the coordinate conversion unit.

4. The continuum robot control system according to claim 3, wherein: The control unit further includes an angle calculation unit configured to calculate a target bending angle of the subsequent bending segment in the relative coordinate system based on the input target bending angle of the distal bending segment in the relative coordinate system, the displacement of the base, and the length of the subsequent bending segment, and The kinematics calculation unit performs the calculation using the target bending angle of the subsequent bending segment in the relative coordinate system calculated by the angle calculation unit.

5. The continuum robot control system according to claim 4, wherein: When calculating the target bending angle of the subsequent bending segment in the relative coordinate system, the angle calculation unit divides the subsequent bending segment into multiple segments, and performs a process of superimposing the target bending angles of the multiple segments in the relative coordinate system when the subsequent bending segment bends following the bending action of the distal bending segment.

6. The continuum robot control system according to any one of claims 3 to 5, wherein: When obtaining the driving amount of the distal linear member in the absolute coordinate system, the coordinate conversion unit adds the driving amount of the subsequent linear member to the driving amount of the distal linear member in the relative coordinate system obtained by the kinematics calculation unit.

7. A continuum robot control method for a continuum robot control system, the system comprising: A continuum robot, comprising: a bendable unit having a plurality of bending segments, each of the plurality of bending segments being configured to bend by a driven linear member; a base configured to support the bendable unit; and a driving unit configured to drive the linear member, wherein the plurality of bending segments of the bendable unit include a distal bending segment and a subsequent bending segment, the distal bending segment being located distal to the base and including a distal fixing member located at the most distal side of the base in the distal bending segment and a distal linear member serving as a linear member fixed to the distal fixing member and driven by the driving unit, the subsequent bending segment being located between the distal bending segment and the base and including a subsequent fixing member located at the most distal side of the base in the subsequent bending segment and a subsequent linear member serving as a linear member fixed to the subsequent fixing member and driven by the driving unit; and a control unit configured to control the motion of the continuum robot, wherein the continuum robot control method comprises: defining a predetermined position on the subsequent fixing member as an origin by the control unit; setting, by the control unit, a reference axis for a direction that the subsequent fixing member faces; and The driving unit is caused by the control unit to drive the distal linear member so that the distal bending section is bent based on a relative coordinate system in which an origin and a reference axis associated with the subsequent fixing member change according to movement of the continuum robot.

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