Patent Description:
Laparoscopic surgery is widely performed because it does not require laparotomy, imposes a small burden on a patient, and provides quick recovery after the surgery. In the laparoscopic surgery, visual field adjustment of an endoscope affects the progress of the surgery, but a control technique is not constant for each operator (surgeon, scopist). Therefore, by introducing a medical arm device (See, for example, Patent Document <NUM>. ) that supports an endoscope, cost reduction such as labor cost of an operator, high accuracy of a control technique of the endoscope, and improvement of safety are achieved.

In the laparoscopic surgery, it is necessary to image the vicinity of a medical instrument such as forceps operated by a surgeon with an endoscope, and parts holding the endoscope and the medical instrument respectively move in the vicinity. If a tip part of the medical arm device that supports the endoscope is large, an operation of the medical instrument by the surgeon is hindered. On the other hand, in order to image a periphery of an affected area at a wide angle, it is necessary to operate the endoscope as wide as possible. Therefore, it is preferable to condense a multi-degree-of-freedom active joint having such a high torque that the endoscope can be held while a tip of the medical arm device is as thin and compact as possible.

Conventionally, a manipulator having a structure in which a small-diameter tip part is driven using a wire or a gear has been proposed (See, for example, Patent Documents <NUM> and <NUM>. If the gear is used, an infinite rotation structure is easily realized, but backlash is easily generated in a transmission part. In a case where a long structure such as an endoscope is supported, if there is backlash, the structure greatly swings, so that a drive mechanism using a gear is not appropriate.

An object of the present disclosure is to provide a medical arm device that is compact and includes a tip part in which a multi-degree-of-freedom active joint is condensed with a high torque so as to be able to hold a medical instrument such as an endoscope.

The present disclosure is defined by the appended set of claims.

According to the present disclosure, it is possible to provide a medical arm device that is small and light, and includes a tip part having a structure in which orthogonal rotation axes of three degrees of freedom that determine an attitude of an endoscope are disposed in a concentrated manner.

Note that the effects described in the present specification are merely examples, and the effects brought by the present disclosure are not limited thereto. Furthermore, the present disclosure may further provide additional effects in addition to the effects described above.

Still other objects, features, and advantages of the present disclosure will become apparent from a more detailed description based on embodiments as described later and the accompanying drawings.

Hereinafter, the technology according to the present disclosure will be described in the following order with reference to the drawings.

The present disclosure is a medical arm device capable of supporting an endoscope at a tip part having an active joint with three degrees of freedom, and determining an attitude of the endoscope by wire-driving each active joint. The present disclosure realizes a medical arm device that satisfies each of the following requirements, suppresses an increase in size of the device, and realizes a higher degree of freedom of an arm and a wider movable range.

<FIG> illustrates an appearance configuration example of a medical arm device <NUM> applied to laparoscopic surgery. The illustrated medical arm device <NUM> has a structure in which an arm having a multi-link structure supports an endoscope at a tip part, and orthogonal rotation axes of three degrees of freedom for determining an attitude of the endoscope are intensively disposed.

Specifically, the medical arm device <NUM> includes: a first link <NUM> attached substantially vertically to a base part; a first joint part <NUM> having a degree of freedom around a horizontal rotation axis (alternatively, a longitudinal axis of the first link <NUM>) at a tip of the first link <NUM>; a second link <NUM> attached horizontally to a tip of the first link <NUM> via the first joint part <NUM>; a second joint part <NUM> having a degree of freedom around a horizontal rotation axis (or an axis orthogonal to the longitudinal axis of the second link <NUM>) at a tip of the second link <NUM>; a third link <NUM> attached substantially vertically to a tip of the second link <NUM> via the second joint part <NUM>; a third joint part <NUM> having a degree of freedom around a vertical rotation axis (or an axis orthogonal to a longitudinal axis of the third link <NUM>) orthogonal to the horizontal rotation axis at a tip of the third link <NUM>, a fourth link <NUM> attached to the tip of the third link <NUM> via the third joint part <NUM>, and a tip part supporting an endoscope at a tip of the fourth link <NUM>. Note that the base part may be attached to, for example, a frame of an operating bed, may be installed on a floor surface of an operating room, or may be installed on a ceiling.

The tip part supporting an endoscope <NUM> at a distal end of the fourth link <NUM> has a structure in which orthogonal rotation axes of three degrees of freedom for determining the attitude of the endoscope <NUM> are intensively arranged. The structure in which the orthogonal rotation axes of three degrees of freedom of the tip part are intensively disposed corresponds to, for example, a structure in which three orthogonal rotation axes are connected without interposing a link, or a structure in which each of joint members corresponding to the three rotation axes is directly connected, and more specifically, a member connecting the three joint parts is not a link that gains an arm length but only a component that connects the joint parts. Note that the tip part that supports the endoscope <NUM> and the fourth link <NUM> having the tip part are referred to as a first arm part. Furthermore, a link part (the first link <NUM> and the second link) including two horizontal rotation axes (the first joint part <NUM> and the second joint part <NUM>) is defined as a second arm part. In the medical arm device <NUM> illustrated in <FIG>, the second arm part is connected by the third joint part <NUM> having a degree of freedom around the vertical rotation axis.

<FIG> illustrates an enlarged structure of the tip part of the medical arm device <NUM> that supports the endoscope <NUM>. The endoscope <NUM> includes a lens barrel <NUM> inserted into a body cavity of a patient at a tip, and a camera head <NUM> connected to a proximal end of the lens barrel <NUM>. The lens barrel <NUM> may be either a rigid mirror including a rigid lens barrel or a flexible mirror including a flexible lens barrel. An optical system and an imaging element (both not illustrated) are disposed in the camera head <NUM>. Reflected light (observation light) from an observation target such as a surgical site is imaged on the imaging element by the optical system. Of course, the tip part of the medical arm device <NUM> may support a medical instrument other than the endoscope <NUM>.

As illustrated in <FIG>, the tip part of the medical arm device <NUM> includes a vertical rotation axis part <NUM> having a degree of freedom around a vertical rotation axis (or an axis orthogonal to a longitudinal axis of the fourth link <NUM>) of the tip of the fourth link <NUM> and swinging the endoscope <NUM> in a vertical direction, a left-right rotation axis part <NUM> that is adjacent to the vertical rotation axis part <NUM>, has a degree of freedom around a left-right rotation axis orthogonal to the vertical rotation axis, and swings the endoscope <NUM> in a left-right direction, and an optical axis rotation axis part <NUM> having a degree of freedom around an optical axis of the endoscope <NUM> (or the lens barrel <NUM> of the endoscope <NUM>). Therefore, the orthogonal rotation axes of three degrees of freedom that determine the attitude of the endoscope <NUM> have a structure in which the optical axis rotation axis of the endoscope <NUM>, the left-right rotation axis, and the vertical rotation axis are disposed in this order from the most tip part.

Note that the left-right rotation axis part <NUM> can be referred to as a pan axis that changes an observation direction of the endoscope <NUM>, and the vertical rotation axis part <NUM> can be referred to as a tilt axis. Alternatively, in a case where the optical axis rotation axis part <NUM> is a roll axis, the left-right rotation axis part <NUM> can be referred to as a yaw axis, and the vertical rotation axis part <NUM> can be referred to as a pitch axis. If a combined volume of the joint parts corresponding to these three axes is smaller than a combined volume of human wrist and hand, there is an advantage of using the medical arm device <NUM> instead of the scopist. The optical axis rotation axis part <NUM> desirably minimizes a length to grip the endoscope <NUM> in an axial direction so as not to reduce an effective length of the endoscope <NUM>. Furthermore, a distance between the vertical rotation axis part <NUM> and the optical axis rotation axis part <NUM> is desirably set to a length that avoids self-interference of the arm.

The structure in which the rotation axes orthogonal to each other with three degrees of freedom are intensively disposed as illustrated in <FIG> is a structure in which the joint members corresponding to the rotation axes with three degrees of freedom are directly connected or a structure in which a distance between the joint corresponding to the rotation axis around the longitudinal axis and the joint corresponding to the pitch axis has a distance that does not cause interference when rotating around the pitch axis. Therefore, it is possible to reduce a space affected by the movement of the tip part, and it is possible to suppress interference with a work space of the surgeon. Incidentally, in a case where the vertical rotation axis part <NUM> is disposed closer to a root side, it is assumed that the movement on a surgeon's hand side becomes large when the vertical rotation axis part <NUM> is operated.

<FIG> illustrates an example in which the medical arm device <NUM> is used for laparoscopic surgery. However, in <FIG>, the base part of the medical arm device <NUM> includes an attachment structure part <NUM> attached to a bed rail <NUM> provided along a length direction on a side part of a surgical bed.

By moving and fixing the attachment structure part <NUM> along the bed rail <NUM>, an arrangement position of the medical arm device <NUM> can be adjusted according to an affected part position of a patient. When the inclination of the surgical bed is adjusted during surgery, a relative positional relationship between the patient and the medical arm device <NUM> can be maintained. During surgery, the surgical bed may be tilted by, for example, about <NUM> deg. Even in such a case, the medical arm device <NUM> according to the present disclosure can be used.

Furthermore, the medical arm device <NUM> can access a free space at hand of the surgeon from an opposite side of the surgeon across the patient (or the operating bed). In this manner, it is possible to avoid interference between the surgeon's hand or arm and the arm tip part by access from the surgeon's face.

Next, a structure for holding the endoscope <NUM> at the tip part of the medical arm device <NUM> will be described in more detail. As also illustrated in <FIG>, the tip part of the medical arm device <NUM> includes the vertical rotation axis part <NUM> having a degree of freedom around the vertical rotation axis and swinging the endoscope <NUM> in the vertical direction, the left-right rotation axis part <NUM> adjacent to the vertical rotation axis part <NUM> and having a degree of freedom around the left-right rotation axis orthogonal to the vertical rotation axis and swinging the endoscope <NUM> in the left-right direction, and the optical axis rotation axis part <NUM> having a degree of freedom around the optical axis of the endoscope <NUM>. Hereinafter, the optical axis rotation axis part <NUM> will be referred to as a roll axis, the left-right rotation axis part <NUM> will be referred to as a yaw axis, and the vertical rotation axis part <NUM> will be referred to as a pitch axis.

<FIG> illustrates an example in which components of the roll axis <NUM>, the yaw axis <NUM>, and the pitch axis <NUM> are disposed at the tip of the fourth link <NUM>. These three axes are active axes, but a driving system using a wire is applied in order to reduce a size of the tip. That is, motors that drive each of the axes of the roll axis <NUM>, the yaw axis <NUM>, and the pitch axis <NUM> are disposed on a root side (proximal end side) of the fourth link <NUM>, and a driving force by an output of each motor is transmitted using a wire and a pulley. <FIG> illustrates structures of a pitch axis wire <NUM>, a yaw axis wire <NUM>, and a roll axis wire <NUM> that tow the components of the pitch axis <NUM>, the yaw axis <NUM>, and the roll axis <NUM>, respectively. Furthermore, <FIG> illustrates a state where a pitch axis motor <NUM>, a yaw axis motor <NUM>, and a roll axis motor <NUM> that drive the pitch axis <NUM>, the yaw axis <NUM>, and the roll axis <NUM>, respectively, are disposed at a base of the fourth link <NUM>.

As illustrated in <FIG>, the motors <NUM> to <NUM> for each axis are disposed on the root side of the fourth link <NUM>. Each of the motors <NUM> to <NUM> is fixed such that its rotation axis is parallel to the pitch axis <NUM>. Then, as also illustrated in <FIG>, the wires <NUM> to <NUM> are extended from output axis pulleys <NUM> to <NUM> of the motors <NUM> to <NUM> toward the tip part, respectively. The fourth link <NUM> extending each of the wires <NUM> to <NUM> long in a straight line corresponds to an "arm", and the three axes of the tip part of the fourth link correspond to a "wrist". If a site from the arm to the wrist can be configured to be thin as a whole, it is effective in avoiding interference between other medical instruments in an abdominal cavity and the tip part and collision between the arm and the surgeon's hand or arm. Therefore, as illustrated in <FIG>, the motors <NUM> to <NUM> for each axis are preferably disposed in a line along a longitudinal direction of the arm, that is, the fourth link <NUM>.

Furthermore, by disposing the motors <NUM> to <NUM> on the root side of the fourth link <NUM>, a torque of a motor group (for example, a motor that drives the third joint part <NUM>) further supporting the fourth link <NUM> is reduced. Therefore, it is preferable to dispose the motors <NUM> to <NUM> for each axis on the root side of the fourth link <NUM> as close as possible to each other.

The pitch axis <NUM> corresponds to a tilt axis that vertically rotates the lens barrel <NUM> of the endoscope <NUM>. In <FIG>, a structure for realizing a rotational degree of freedom around the pitch axis <NUM> in the tip part of the medical arm device <NUM> is extracted and illustrated. Furthermore, in <FIG>, an outline of other parts such as the fourth link <NUM> is indicated by a dotted line.

Near the tip of the fourth link <NUM>, a pitch axis component <NUM> is supported by a shaft <NUM> coaxial with the pitch axis <NUM> so as to be rotatable around the pitch axis <NUM>. Furthermore, as illustrated in <FIG>, since the pitch axis motor <NUM> is disposed such that the output axis is parallel to the pitch axis <NUM>, the other end of the pitch axis wire <NUM> wound around the output axis pulley <NUM> of the pitch axis motor <NUM> is wound around a pulley <NUM> integrated with the pitch axis component <NUM>, so that the tip parts of the pitch axis component <NUM> and the subsequent parts can be rotationally driven around the pitch axis <NUM>. In the example illustrated in <FIG>, the pitch axis wire <NUM> is directly wound around the output axis of the pitch axis motor <NUM> and the pulley <NUM> without interposing other pulleys. However, the pitch axis wire <NUM> may be wound around the pulley <NUM> after a path is adjusted using other pulleys as necessary.

The pitch axis <NUM> (alternatively, the pitch axis component <NUM>) can structurally have a rotation movable range of about ± <NUM> deg. However, the pitch axis <NUM> is a tilt axis of the endoscope <NUM>, and if considering holding the endoscope <NUM>, a rotation movable range of about ± <NUM> deg is sufficient. Rather, if the rotation movable range around the pitch axis <NUM> is too large, the endoscope <NUM> may collide with an arm such as the fourth link <NUM>. As a structural design, in a case where the rotation movable range of the pitch axis <NUM> may be less than ± <NUM> deg, the pulley <NUM> is only required to be a single-groove pulley as illustrated in <FIG>. In a case where a rotation movable range of the pitch axis <NUM> of ± <NUM> deg or more is required, the pitch axis wire <NUM> may be wound around different grooves in a forward path and a backward path with the pulley <NUM> as a two-groove pulley.

The structure for realizing the rotational degree of freedom around the pitch axis <NUM> illustrated in <FIG> is a simple structure in which an output torque of the pitch axis motor <NUM> disposed in parallel to the pitch axis <NUM> is transmitted to the pulley <NUM> by the pitch axis wire <NUM>. It is easy to replace the output torque of the pitch axis motor <NUM> with a transmission mechanism such as a link mechanism or a gear mechanism other than the pitch axis wire <NUM> to form a structure for realizing the rotational degree of freedom around the pitch axis <NUM>. Furthermore, the pitch axis <NUM> may be directly rotationally driven by the pitch axis motor <NUM> without using the transmission mechanism.

The yaw axis <NUM> corresponds to a pan axis that changes the observation direction of the endoscope <NUM>. In <FIG> and <FIG>, a structure for realizing the rotational degree of freedom around the yaw axis <NUM> in the tip part of the medical arm device <NUM> is extracted and illustrated. Furthermore, in <FIG> and <FIG>, an outline of other components such as the fourth link <NUM> is indicated by a dotted line.

A yaw axis pulley <NUM> is supported on a tip surface of the pitch axis component <NUM> (not illustrated in <FIG> and <FIG>) so as to be rotatable coaxially with the yaw axis <NUM>. Furthermore, as illustrated in <FIG>, the yaw axis motor <NUM> is disposed on the root side of the fourth link <NUM> such that the rotation axis is parallel to the pitch axis <NUM> together with the pitch axis motor <NUM> and the roll axis motor <NUM>. Then, by winding the yaw axis wire <NUM> wound around the output axis pulley <NUM> of the yaw axis motor <NUM> around the yaw axis pulley <NUM> while adjusting the path via each of pulleys <NUM>, <NUM>, <NUM>, and <NUM>, the tip part of the yaw axis pulley <NUM> and the subsequent parts can be rotationally driven around the yaw axis <NUM>.

A structure in which the yaw axis wire <NUM> is wound around the yaw axis pulley <NUM> will be specifically described. As a winding structure of the yaw axis wire <NUM>, the two-groove pulley <NUM> that is rotatable around a rotation axis parallel to the pitch axis <NUM> on the root side of the pitch axis <NUM> and corresponds to rotation around the pitch axis <NUM>, the two-groove pulley <NUM> that is rotatable around the pitch axis <NUM> and changes the path along the pitch axis <NUM>, and the two rerouting pulleys <NUM> and <NUM> that change the path of the yaw axis wire <NUM> between the pitch axis and the yaw axis are used.

The two-groove pulley <NUM> is rotatably supported around a rotation axis parallel to the pitch axis <NUM> by the shaft <NUM> on the root side of the pitch axis <NUM>, and the two-groove pulley <NUM> is rotatably supported around the pitch axis <NUM> by the shaft <NUM> coaxial with the pitch axis <NUM> (See the above and <FIG>. Furthermore, the rerouting pulleys <NUM> and <NUM> are supported on side surfaces on an opposite side of the pitch axis component <NUM> (not illustrated in <FIG> and <FIG>) so as to be rotatable on the identical axis around an axis orthogonal to the pitch axis <NUM> and the yaw axis <NUM>.

On a forward path side, when the yaw axis wire <NUM> comes out of the output axis pulley <NUM> (not illustrated in <FIG> and <FIG>) of the yaw axis motor <NUM>, the yaw axis wire is wound around the two-groove pulley <NUM> on the root side and the two-groove pulley <NUM> coaxial with the pitch axis <NUM> in this order from the longitudinal direction (or the pitch axis direction) of the fourth link <NUM> to change the path along the pitch axis, then wound around the rerouting pulley <NUM> to change the path from the pitch axis direction to the yaw axis direction, and wound around the yaw axis pulley <NUM>.

Furthermore, on a backward path side, when the yaw axis wire <NUM> is wound around the rerouting pulley <NUM> immediately after coming out of the yaw axis pulley <NUM> and rerouted from the yaw axis direction to the pitch axis direction, the yaw axis wire is wound around the two-groove pulley <NUM> coaxial with the pitch axis <NUM> and the two-groove pulley <NUM> on the root side in this order to change the route along the pitch axis, and then wound around the output axis pulley <NUM> (not illustrated in <FIG> and <FIG>) of the yaw axis motor <NUM>.

Next, a method of fixing the yaw axis pulley <NUM> and the yaw axis wire <NUM> will be considered. The yaw axis pulley <NUM> is a two-groove pulley, and the forward path and the backward path of the yaw axis wire <NUM> are fixed to different grooves, so that the yaw axis <NUM> can have a rotation movable range of ± <NUM> deg or more. However, in the present embodiment, as a basic structure, the rotation movable range around the yaw axis <NUM> is ± <NUM> deg. The larger a diameter of the yaw axis pulley <NUM> is, the larger a transmission torque can be handled, which is preferable. It is important for simplification of the structure that the diameter of each groove of the two-groove pulley used for the yaw axis pulley <NUM> is the same.

In the configuration example illustrated in <FIG> and <FIG>, two rerouting pulleys <NUM> and <NUM> are used to reroute the yaw axis wire <NUM> between the pitch axis and the yaw axis. If the rerouting pulleys <NUM> and <NUM> are configured by disposing two pulleys having different diameters on the identical axis in order to reduce the number of parts and simplify the structure, the yaw axis wire <NUM> can be smoothly rerouted with good compatibility with the two-groove pulley <NUM>. In the example illustrated in <FIG>, a diameter of the rerouting pulley <NUM> is larger than that of the rerouting pulley <NUM>. Therefore, on the forward path side of the yaw axis wire <NUM>, the path is changed from the pitch axis direction to the yaw axis direction by the rerouting pulley <NUM> while being wound around a groove inside the two-groove pulley <NUM>, and on the backward path side of the yaw axis wire <NUM>, the path is changed from the yaw axis direction to the pitch axis direction by the rerouting pulley <NUM>, and then the yaw axis wire is wound around a groove outside the two-groove pulley <NUM>.

Furthermore, in order to change the path of the yaw axis wire <NUM> along the pitch axis direction, it is important that the diameter of each groove of the two-groove pulley <NUM> coaxial with the pitch axis <NUM> is the same, and it is further preferable that the diameter is the same as a diameter of the yaw axis pulley <NUM> in terms of design.

Furthermore, the diameter of each groove of the two-groove pulley <NUM> on the root side of the pitch axis <NUM> is not necessarily the same. From the viewpoint of weight reduction, the two-groove pulley <NUM> is preferably small.

<FIG> is a cross-sectional view of the tip part of the medical arm device <NUM> taken along a plane (alternatively, a plane orthogonal to the roll axis) parallel to the pitch axis and the yaw axis. As illustrated in the figure, a first connection part <NUM> connected to the pitch axis component <NUM> is disposed on the root side (or proximal end side) of the yaw axis pulley <NUM>. Furthermore, a second connection part <NUM> connected to a roll axis component (roll axis pulley) as described later is disposed on a tip side (alternatively, a distal end side) of the yaw axis pulley <NUM>. The yaw axis pulley <NUM>, and the first connection part <NUM> and the second connection part <NUM> are integrally fastened by a fixing method such as a screw to constitute a yaw axis component. Therefore, when the yaw axis pulley <NUM> is rotated around the yaw axis, the first connection part <NUM> and the second connection part <NUM> are also interlocked. The roll axis component also rotates around the yaw axis <NUM> following the second connection part <NUM>.

Note that <FIG> also illustrates an arrangement of a bearing. In <FIG>, a bearing part is filled with a dot pattern. The yaw axis component is supported at the first connection part <NUM> via the bearing to be rotatable around the yaw axis <NUM> relative to the pitch axis component <NUM>. Furthermore, the yaw axis component supports a roll axis component (described later) (not illustrated) via the bearing so as to be rotatable around the roll axis <NUM> at the second connection part <NUM>.

The two-groove pulley <NUM> for accommodating rotation around the pitch axis <NUM> is supported by the shaft <NUM> having a rotation axis parallel to the pitch axis <NUM> via a bearing, and is rotatable coaxially with the shaft <NUM>. The two-groove pulley <NUM> for rerouting along the pitch axis <NUM> is supported by the shaft <NUM> coaxial with the pitch axis <NUM> via the bearing, and is rotatable coaxially with the shaft <NUM>, that is, around the pitch axis <NUM>.

Furthermore, as will be described later, a two-groove pulley <NUM> for accommodating rotation around the pitch axis <NUM> and a two-groove pulley <NUM> for changing the path along the pitch axis <NUM> are used as components for realizing the rotational degree of freedom around the roll axis. The two-groove pulley <NUM> is supported by the shaft <NUM> having a rotation axis parallel to the pitch axis <NUM> via the bearing, and is rotatable coaxially with the shaft <NUM>. The two-groove pulley <NUM> is supported by the shaft <NUM> coaxial with the pitch axis <NUM> via the bearing, and is rotatable coaxially with the shaft <NUM>, that is, around the pitch axis <NUM>.

The roll axis <NUM> corresponds to an optical axis of the lens barrel <NUM> of the endoscope <NUM>. In <FIG> and <FIG>, a structure for realizing the rotational degree of freedom around the roll axis <NUM> in the tip part of the medical arm device <NUM> is extracted and illustrated. Furthermore, in <FIG> and <FIG>, an outline of other components such as the fourth link <NUM> is indicated by a dotted line.

The roll axis pulley <NUM> is supported by the tip part of the second connection part <NUM> via a bearing so as to be rotatable around the roll axis <NUM> (see <FIG>). The roll axis pulley <NUM> is a structure body including a hollow cylinder, and includes pulleys 1101a and 1101b for winding a set of a forward path and a backward path of the roll axis wire <NUM> around both ends of the cylinder. One set of the pulleys 1101a and 1101b is integrally fastened so as to rotate around the roll axis <NUM> to constitute the pulley <NUM>. Although not illustrated in <FIG> and <FIG>, the endoscope <NUM> is attached inside a cylinder of the roll axis pulley <NUM>. Furthermore, as illustrated in <FIG>, the roll axis motor <NUM> is disposed on the root side of the fourth link <NUM> such that the rotation axis is parallel to the pitch axis <NUM> together with the pitch axis motor <NUM> and the yaw axis motor <NUM>. Then, both ends of the roll axis wire <NUM> wound around the output axis pulley <NUM> of the roll axis motor <NUM> are respectively wound around the set of pulleys 110a1 and 1101b of the roll axis pulley <NUM> via a plurality of the pulleys <NUM>, <NUM>,. , so that the endoscope <NUM> (or the lens barrel <NUM>) attached to the roll axis pulley <NUM> can be rotationally driven around the roll axis <NUM>.

A structure in which the roll axis wire <NUM> is wound around the roll axis pulley <NUM> will be specifically described. As the winding structure of the roll axis wire <NUM>, the two-groove pulley <NUM> that is rotatable around a rotation axis parallel to the pitch axis <NUM> on the root side of the pitch axis <NUM> and accommodates rotation around the pitch axis <NUM>, the two-groove pulley <NUM> that is rotatable around the pitch axis <NUM> and changes the path along the pitch axis <NUM>, two rerouting pulleys <NUM> and <NUM> that change the path of the roll axis wire <NUM> between the pitch axis and the yaw axis, a two-groove pulley <NUM> coaxial with the yaw axis <NUM> that changes the path along the yaw axis <NUM>, and two rerouting pulleys <NUM> and <NUM> that change the path of the roll axis wire <NUM> between the yaw axis and the roll axis are used.

The two-groove pulley <NUM> is rotatably supported around a rotation axis parallel to the pitch axis <NUM> by the shaft <NUM> on the root side of the pitch axis <NUM>, and the two-groove pulley <NUM> is rotatably supported around the pitch axis <NUM> by the shaft <NUM> coaxial with the pitch axis <NUM> (See the above and <FIG>. The rerouting pulleys <NUM> and <NUM> are respectively supported on side surfaces on an opposite side of the pitch axis component <NUM> (not illustrated in <FIG> and <FIG>) so as to be rotatable on the identical axis around an axis orthogonal to the pitch axis <NUM> and the yaw axis <NUM>. The two-groove pulley <NUM> is supported on a tip surface of the pitch axis component <NUM> via a bearing so as to be rotatable around the yaw axis <NUM> (See <FIG>. The rerouting pulley <NUM> is supported on a side surface of the second connection part <NUM> (not illustrated in <FIG> and <FIG>) so as to be rotatable around an axis parallel to the roll axis <NUM>. Furthermore, the reroute <NUM> is supported on a side surface of the second connection part <NUM> (not illustrated in <FIG> and <FIG>) so as to be rotatable around an axis orthogonal to the roll axis <NUM>.

On the forward path side, when the roll axis wire <NUM> comes out of the output axis pulley <NUM> (not illustrated in <FIG> and <FIG>) of the roll axis motor <NUM>, the roll axis wire is wound around the rerouting pulley to change the route along the pitch axis by winding the two-groove pulley <NUM> on the root side and the two-groove pulley <NUM> coaxial with the pitch axis <NUM> in this order from the longitudinal direction (or the pitch axis direction) of the fourth link <NUM>, then wound around the rerouting pulley <NUM> to change the path from the pitch axis direction to the yaw axis direction, then wound around the two-groove pulley <NUM> to change the path along the yaw axis, further wound around the rerouting pulley <NUM> to change the path from the yaw axis direction to the roll axis direction, and wound around one pulley 1101a of the roll axis pulley <NUM>.

Furthermore, on the backward path side, the roll axis wire <NUM> is wound around the rerouting pulley <NUM> immediately after coming out of the other pulley 1101b of the roll axis pulley <NUM> to change the path from the roll axis direction to the yaw axis direction, then wound around the two-groove pulley <NUM> to change the path along the yaw axis, further wound around the rerouting pulley <NUM> to change the path from the yaw axis direction to the pitch axis direction, then wound around the two-groove pulley <NUM> coaxial with the pitch axis <NUM> and the two-groove pulley <NUM> on the root side in this order to change the path along the pitch axis, and then wound around the output axis pulley <NUM> (not illustrated in <FIG> and <FIG>) of the roll axis motor <NUM>.

Next, a method of fixing the roll axis pulley <NUM> and the roll axis wire <NUM> will be considered. The roll axis pulley <NUM> includes a set of pulleys 1101a and 1101b, but may be a two-groove pulley similarly to the yaw axis. In the present embodiment, as a basic structure, the rotation movable range around the roll axis <NUM> is ± <NUM> deg. A diameter of the set of pulleys 1101a and 1101b of the roll axis pulley <NUM> needs to be the same. It is preferable that these diameters are larger because a larger transmission torque can be handled.

In the example illustrated in <FIG> and <FIG>, the two rerouting pulleys <NUM> and <NUM> that reroute the roll axis wire <NUM> between the yaw axis and the roll axis are used, but one of the pulleys interferes with the two rerouting pulleys <NUM> and <NUM> that reroute the roll axis wire <NUM> between the pitch axis and the yaw axis. In order to avoid such interference between the pulleys, as described above, the rotation movable range around the yaw axis <NUM> is ± <NUM> deg.

In order to change the path along the pitch axis, the two-groove pulley <NUM> on the root side of the pitch axis <NUM> and the two-groove pulley <NUM> coaxial with the pitch axis <NUM> are used, but it is important that these two-groove pulleys <NUM> and <NUM> have the same diameter as each other. Further, it is preferable in design that these two-groove pulleys <NUM> and <NUM> have the same diameter as the roll axis pulley <NUM>.

In the examples illustrated in <FIG> and <FIG>, the two rerouting pulleys <NUM> and <NUM> that reroute the roll axis wire <NUM> between the pitch axis and the yaw axis are used. However, in order to reduce the number of parts and simplify the structure, when the rerouting pulleys <NUM> and <NUM> are configured by disposing two pulleys having different diameters on the identical axis, the roll axis wire <NUM> can be smoothly rerouted with good compatibility with the two-groove pulley <NUM>. In the example illustrated in <FIG> and <FIG>, a diameter of the rerouting pulley <NUM> is larger than that of the rerouting pulley <NUM>. Therefore, on the forward path side of the roll axis wire <NUM>, the path is changed from the yaw axis direction to the pitch axis direction by the rerouting pulley <NUM> while being wound around a groove inside the two-groove pulley <NUM>, and on the backward path side of the roll axis wire <NUM>, the path is changed from the pitch axis direction to the yaw direction by the rerouting pulley <NUM>, and then the roll axis wire is wound around the outside of the two-groove pulley <NUM>.

Furthermore, in order to change the path of the roll axis wire <NUM> along the pitch axis direction, it is important that the diameter of each groove of the two-groove pulley <NUM> coaxial with the pitch axis <NUM> is the same, and it is further preferable that the diameter is the same as that of the yaw axis pulley <NUM> in terms of design.

As described with reference to <FIG>, the basic structure has a structure in which the motors <NUM> to <NUM> for three-axis drive are disposed as close as possible to each other, and the tip part can be driven by wire drive.

Note that regarding the drive of the pitch axis <NUM>, only the rotation between two parallel axes, that is, the pitch axis <NUM> and the output axis of the pitch axis motor <NUM> is transmitted. Therefore, it is possible to replace the transmission method with any transmission method such as a belt, a gear, or a link mechanism.

Next, a method of controlling the tip part described in section C described above will be described. First, symbols used in the following description will be described.

Furthermore, the definitions of the positive and negative directions of the rotation of the pitch axis <NUM>, the yaw axis <NUM>, the roll axis <NUM>, and the output axes of the motor <NUM> to <NUM> for each axis are as illustrated in <FIG>.

Inverse kinematics is obtained on the basis of the conditions described above. The rotation angles θmp, θmy, and θmr of the output axes of the motors <NUM> to <NUM> for driving each axis are derived as in the following formulas (<NUM>) to (<NUM>) on the basis of the respective rotation angles θp, θy, and θr of the pitch axis <NUM>, the yaw axis <NUM>, and the roll axis <NUM> at the tip part. [Mathematical formula <NUM>] <MAT> [Mathematical formula <NUM>] <MAT> [Mathematical formula <NUM>] <MAT> Here, the rotation angle θmp θmy, or θmr of the output axis of each of the motors <NUM> to <NUM> can be measured by an encoder attached to the output axis of each of the motors <NUM> to <NUM>.

In a case where each of the rotation angles θp, θy, and θr of the pitch axis <NUM>, the yaw axis <NUM>, and the roll axis <NUM> of the tip part is obtained by forward kinematics, it is only necessary to arrange the simultaneous equations (<NUM>) to (<NUM>) described above with respect to each of the rotation angles θp, θy, and θr, and the rotation angles θp, θy, and θr are obtained as the following formulas (<NUM>) to (<NUM>). [Mathematical formula <NUM>] <MAT> [Mathematical formula <NUM>] <MAT> [Mathematical formula <NUM>] <MAT> By using the above formulas (<NUM>) to (<NUM>), it is possible to derive a rotation movable range that needs to be adaptable to each motor and each pulley.

First, the rotation movable range of each of the joint angles θp, θy, and θr of the pitch axis <NUM>, the yaw axis <NUM>, and the roll axis <NUM> is set in a range represented by the following formula (<NUM>), (<NUM>), or (<NUM>), as described above. [Mathematical formula <NUM>] <MAT> [Mathematical formula <NUM>] <MAT> [Mathematical formula <NUM>] <MAT>.

By setting Ry = Rpy and Rr = Rpr = Ryr in terms of a mechanical design, it is possible to generate the path of the wires <NUM> to <NUM> simply, at low cost, and smoothly. By substituting the values described above in consideration of this, the rotation angle θmp, θmy, or θmr of the output axis of each motor <NUM>, <NUM>, or <NUM> necessary for realizing the rotation movable range of each joint shown in the above formula (<NUM>), (<NUM>), or (<NUM>) can be simply calculated as in the following formula (<NUM>), (<NUM>), or (<NUM>). [Mathematical formula <NUM>] <MAT> [Mathematical formula <NUM>] <MAT> [Mathematical formula <NUM>] <MAT>.

Strictly speaking, although it depends on the design, rotation movable ranges in which the rotation angle θmp of the output axis of the pitch axis motor <NUM> is about half rotation, the rotation angle θmy of the output axis of the yaw axis motor <NUM> is about one rotation, and the rotation angle θmr of the output axis of the roll axis motor <NUM> is about two rotations are required. Therefore, the wire <NUM> is spirally wound around the output axis pulley <NUM> of the roll axis motor <NUM> so as to be rotatable by two or more rotations.

Incidentally, one rotation is insufficient for an absolute encoder mounted on an output axis of a motor requiring a rotation movable range exceeding one rotation. Therefore, it is necessary to mount a multi-rotation absolute encoder or mount an absolute encoder in a joint part (for example, the roll axis pulley <NUM>).

A multi-rotation absolute encoder generally needs to hold what rotation it is, and examples thereof include a method of mounting a battery and electrically holding the absolute encoder or a method of mechanically holding the absolute encoder using a structure such as a screw, but there is a problem that the number of parts and weight increase in any method. On the other hand, in a case where the absolute encoder is mounted in the joint part, there is a problem that the number of wires to the tip part of the arm increases, and it is necessary to devise wiring, and the weight of the tip part increases, so that the load of each of the motor <NUM> to <NUM> also increases.

Therefore, in the present disclosure, a method of deriving the number of rotations from a measurement value of the one-rotation absolute encoder is used for the output axis of the roll axis motor <NUM>.

The rotation angle θmp, θmy, or θmr of the output axis of the motor <NUM>, <NUM>, or <NUM> for each axis corresponding to each of the target angles θp, θy, and θr of the pitch axis <NUM>, the yaw axis <NUM>, and the roll axis <NUM> was derived using the inverse kinematics shown in the above formulas (<NUM>) to (<NUM>) so as to cover all the attitudes of the tip part. As a result, it has been found that the rotation angles θmp, θmy, and θmr of the output axes of the motors <NUM> to <NUM> for each axis vary within the ranges of the following formulas (<NUM>) to (<NUM>), respectively, which are consistent with the results of the simple calculation shown in the above formulas (<NUM>) to (<NUM>). [Mathematical formula <NUM>] <MAT> [Mathematical formula <NUM>] <MAT> [Mathematical formula <NUM>] <MAT>.

Here, it is assumed that a one-rotation absolute encoder is mounted on the roll axis <NUM>, and the rotation angle θr of the roll axis <NUM> can be measured in a range of <NUM> to <NUM> deg. Then, a value obtained by converting the rotation angle θmr of the output axis of the roll axis motor <NUM> so as to fall within this angle range is set as a pseudo roll axis motor output rotation angle θmr_1.

Therefore, it is sufficient that the forward kinematics calculation shown in the above formulas (<NUM>) to (<NUM>) is performed using this value θmr_1 instead of the original rotation angle θmr of the motor output axis, and the attitude of the tip part can be derived similarly.

When each of the target angles θp, θy, and θr of the pitch axis <NUM>, the yaw axis <NUM>, and the roll axis <NUM> is calculated by the forward kinematics calculation using the value θmr_1 so as to cover all the attitudes of the tip part, it can be confirmed that a value matching the original target value (that is, when calculated using the original value θmr) can be derived for each of the target angles θp and θy of the pitch axis <NUM> and the yaw axis <NUM>. On the other hand, with respect to the target angle θr_1r of the roll axis <NUM> derived using an alternative value θmr_1r, it has been confirmed that the value is divided into two groups, and one group is lower than -<NUM> deg that is a rotation movable range limit of the roll axis <NUM>. This is because, by using a one-rotation absolute encoder for the output axis of the roll axis motor <NUM>, a numerical value such as -<NUM> deg is originally measured as <NUM> deg. Therefore, in the present disclosure, the forward kinematics described in the above formulas (<NUM>) to (<NUM>) is corrected to the following formulas (<NUM>) to (<NUM>). [Mathematical formula <NUM>] <MAT> [Mathematical formula <NUM>] <MAT> [Mathematical formula <NUM>] <MAT> [Mathematical formula <NUM>] <MAT> [Mathematical formula <NUM>] <MAT>.

It could be confirmed that the original attitude of the tip part could be derived using the forward kinematics represented by the above formulas (<NUM>) to (<NUM>). Therefore, by introducing the correction calculation using the above formulas (<NUM>) and (<NUM>), it can be seen that the attitude of the tip part can be easily derived using the forward kinematics represented by the above formulas (<NUM>) to (<NUM>) only by mounting the one-rotation absolute encoder on the output axis of the motors <NUM> to <NUM> for each axis.

However, in order to establish the correction calculation using the above formulas (<NUM>) and (<NUM>), it is required that the radius Rmr of the output axis pulley <NUM> of the roll axis motor <NUM> is larger than the radius Rr of the roll axis pulley <NUM>, that is, the following formula (<NUM>) is satisfied. Therefore, the rotation movable range of the rotation angle θmr of the output axis of the roll axis motor <NUM> can be suppressed to within two rotations. [Mathematical formula <NUM>] <MAT>.

Note that in terms of safely transmitting a large torque, the radius Rp of the pulley <NUM> for driving the pitch axis <NUM>, the radius Ry of the yaw axis pulley <NUM>, and the radius of the roll axis pulley <NUM> may each be as large as possible. It is preferable to select a larger diameter of the pulley within a range in which the arm and the wrist of the medical arm device <NUM> can be sufficiently downsized.

In the endoscope holding structure described in section C described above, the two rerouting pulleys <NUM> and <NUM> that reroute the roll axis wire <NUM> between the yaw axis and the roll axis are used (See <FIG> and <FIG>. Among them, the rerouting pulley <NUM> is supported on the side surface of the second connection part <NUM> so as to be rotatable around an axis parallel to the roll axis <NUM>, and the reroute <NUM> is supported on the side surface of the second connection part <NUM> so as to be rotatable around an axis orthogonal to the roll axis <NUM>. On the other hand, in a second endoscope holding structure, the rerouting pulley <NUM> is reduced to reduce the number of components and the total length of the wire <NUM>. In <FIG> and <FIG>, a structure for realizing a rotational degree of freedom around the roll axis <NUM> in the second endoscope holding structure is extracted and illustrated.

As described above, the rerouting pulley <NUM> plays a role of rerouting the roll axis wire <NUM> on the forward path side from the yaw axis direction to the roll axis direction. On the other hand, in the second endoscope holding structure, as illustrated in <FIG> and <FIG>, the path of the roll axis wire <NUM> is changed from the yaw axis direction to the roll axis direction without using the rerouting pulley <NUM> by directly winding the roll axis wire <NUM> from the two-groove pulley <NUM> to the pulley 1101a. In <FIG> and <FIG>, positions where the roll axis wire <NUM> is passed from the two-groove pulley <NUM> to the pulley 1101a are indicated by reference numerals <NUM> and <NUM>, respectively. By shortening a distance between the yaw axis pulley <NUM> and the roll axis <NUM>, the wire <NUM> can be directly passed from the two-groove pulley <NUM> to the roll axis pulley 1101a, and the rerouting pulley <NUM> can be reduced.

In the second endoscope holding structure, there is an advantage that the number of components and the total length of the wire <NUM> are shortened by the reduction of the pulley <NUM>. However, since the path is changed from the yaw axis direction to the roll axis direction by directly passing the wire <NUM> from the two-groove pulley <NUM> to the roll axis pulley 1101a, attention should be paid to wear of the wire <NUM>, increased resistance during rotation, and derailment of the wire <NUM>.

Note that, in the second endoscope holding structure illustrated in <FIG> and <FIG>, the same kinematics as that of the endoscope holding structure described in section C described above (See section D described above. ) can be applied.

In the endoscope holding structure described in section C described above, when the endoscope holding structure rotates around the yaw axis <NUM>, interference occurs between the rerouting pulley <NUM> that reroutes from the yaw axis direction to the roll axis direction and the rerouting pulley <NUM> that reroutes from the pitch axis direction to the yaw axis direction (See <FIG>. Therefore, the rotation movable range on one side around the yaw axis <NUM> is limited to about <NUM> deg.

The interference between the rerouting pulleys will be described in detail. <FIG> illustrates the endoscope holding structure (tip part of the medical arm device <NUM>) described in section C described above as viewed from above. It can be seen from <FIG> that the rerouting pulley <NUM> that reroutes from the yaw axis direction to the roll axis direction and the rerouting pulley <NUM> from the roll axis direction to the yaw axis direction are dispersedly disposed on the side surface of the second connection part <NUM> facing the roll direction and the side surface orthogonal thereto. Furthermore, from <FIG>, the rerouting pulley <NUM> that reroutes from the pitch axis direction to the yaw axis direction and the rerouting pulley <NUM> that reroutes from the yaw axis direction to the pitch axis direction are supported on the side surface of the pitch axis component <NUM> so as to be rotatable around a common (or parallel to each other. ) axis orthogonal to the pitch axis <NUM>. In such arrangement of each of the rerouting pulleys <NUM> to <NUM>, as described with reference to <FIG>, when the rotation movable range around the yaw axis <NUM> is increased, there is a risk that the rerouting pulleys interfere with each other in the vicinity of the yaw axis pulley <NUM>.

On the other hand, in a third endoscope holding structure, the two rerouting pulleys <NUM> and <NUM> for rerouting the wire <NUM> between the pitch axis and the yaw axis and the two rerouting pulleys <NUM> and <NUM> for rerouting the wire <NUM> between the yaw axis and the roll axis are collected and disposed in as narrow ranges as possible, thereby reducing the risk of interference between the rerouting pulleys as much as possible. <FIG> illustrates the endoscope holding structure (tip part of the medical arm device <NUM>) described in section C described above as viewed from above.

Specifically, in the third endoscope holding structure, the two rerouting pulleys <NUM> and <NUM> that reroute the wire <NUM> between the pitch axis and the yaw axis are disposed such that the rotation axes thereof cross each other, thereby minimizing a region where each of the rerouting pulleys <NUM> and <NUM> is in contact with the yaw axis pulley <NUM>.

Furthermore, in the third endoscope holding structure, the two rerouting pulleys <NUM> and <NUM> that reroute the wire <NUM> between the yaw axis and the roll axis are collectively disposed on the side surface of the second connection part <NUM> facing a direction orthogonal to the roll axis <NUM>, so that a region where each of the rerouting pulleys <NUM> and <NUM> is in contact with the yaw axis pulley <NUM> is minimized. As can be seen by comparing <FIG> with <FIG>, the rerouting pulley <NUM> is disposed to move from the side surface of the second connection part <NUM> facing the roll axis <NUM> to the side surface of the second connection part <NUM> facing a direction orthogonal to the roll axis <NUM>.

As described above, by minimizing the regions where each of the rerouting pulleys <NUM> and <NUM> and the rerouting pulleys <NUM> and <NUM> is in contact with the yaw axis pulley <NUM>, it is possible to suppress the risk of interference between the rerouting pulleys when the roll axis component greatly rotates around the yaw axis <NUM>.

<FIG> illustrates a state where the third endoscope holding structure is rotated in a positive direction of the yaw axis <NUM>. Furthermore, <FIG> illustrates a state where the third endoscope holding structure is rotated in a negative direction of the yaw axis <NUM>. It can be understood from <FIG> and <FIG> that interference between the rerouting pulleys can be avoided when the rotation is performed around the yaw axis <NUM>. According to the third endoscope holding structure, a rotation movable range of about ± <NUM> deg around the yaw axis <NUM> can be realized.

Note that, referring to <FIG>, on the forward path side, the roll axis wire <NUM> is wound around the two-groove pulley <NUM> along the yaw axis, then wound around the rerouting pulley <NUM> to change the path from the yaw axis direction to a direction orthogonal to the roll axis, further wound around the rerouting pulley <NUM> to change the path from the direction orthogonal to the roll axis to the roll axis direction, and then wound around one pulley 1101a of the roll axis pulley <NUM>. Since the rerouting pulley <NUM> is disposed by moving to the side surface of the second connection part <NUM> facing the direction orthogonal to the roll axis <NUM> (described above), the rerouting pulley <NUM> for rerouting the wire <NUM> from the direction orthogonal to the roll axis to the roll axis direction is required. The rerouting pulley <NUM> is disposed at a high position on the side surface of the second connection part <NUM> so as to avoid interference with the other rerouting pulleys <NUM> and <NUM> during rotation around the yaw axis <NUM>.

Furthermore, in a case where the roll axis part (the roll axis pulley <NUM>) is allowed to become slightly larger, or in a case where it is desired to wind the roll axis wire <NUM> around one of the set of pulleys 1101a and 1101b, the two rerouting pulleys <NUM> and <NUM> for changing the route of the wire <NUM> between the yaw axis and the roll axis may also be disposed such that the rotation axes thereof cross each other (not illustrated).

In the endoscope holding structure described above, in a case where a stainless wire rope or the like is used as the wires <NUM> to <NUM> for driving each axis, it is possible to generate a torque sufficient to support the endoscope <NUM> at the tip part of the medical arm device <NUM>.

<FIG> illustrates that the motors <NUM> to <NUM> for each axis are disposed on the root side of the fourth link <NUM> as close as possible to each other. It is computationally known that a moment can be suppressed to about <NUM>/<NUM> compared to a case where these actuators are disposed at the distal end of the arm, such as the tip side of the fourth link <NUM>. Therefore, the arrangement of the motors <NUM> to <NUM> for each axis illustrated in <FIG> can reduce the weight of the tip part and reduce the load on the motors <NUM> to <NUM> for each axis.

<FIG> illustrates an example in which the pitch axis motor <NUM>, the yaw axis motor <NUM>, and the roll axis motor <NUM> are disposed in this order from the tip side, but the order of disposing these motors may be changed. However, it is preferable to dispose the heavy motors in this order from the root side (or the proximal end side) because the output required for driving the three degrees of freedom of the tip part can be reduced.

On the other hand, since a high torque is required for driving around the pitch axis <NUM>, as illustrated in <FIG>, disposing each component such that the pulley group (See, for example, <FIG> and <FIG>. ) of the pitch axis wire <NUM> is located inside the pulley group (See, for example, <FIG> and <FIG>. ) for driving around the yaw axis <NUM> and the pulley group (See, for example, <FIG> and <FIG>. ) for driving around the roll axis <NUM> can contribute to downsizing and high torque.

Furthermore, since the roll axis <NUM> is used for the optical axis rotation of the endoscope <NUM> (See <FIG>. ), a small torque is sufficient, and there is no problem in design even if the group of pulleys for driving around the roll axis <NUM> is disposed on the outermost side.

To sum up, as illustrated in <FIG>, it can be said that it is ideal to dispose the pitch axis motor <NUM>, the yaw axis motor <NUM>, and the roll axis motor <NUM> in this order from the tip side.

As described in section C-<NUM> described above, the two-groove pulley <NUM> is used on a front side (proximal end side) of the pitch axis <NUM> in order to make the yaw axis wire <NUM> accommodate the rotation around the pitch axis <NUM>. Furthermore, as described in section C-<NUM> described above, the two-groove pulley <NUM> is used on the front side (proximal end side) of the pitch axis <NUM> in order to make the roll axis wire <NUM> accommodate the rotation around the pitch axis <NUM>.

Both of these two two-groove pulleys <NUM> and <NUM> are supported by the shaft <NUM> parallel to the pitch axis <NUM>. The two-groove pulleys <NUM> and <NUM> accommodating the pitch axis rotation are preferably close to the two-groove pulleys <NUM> and <NUM> coaxial with the pitch axis, respectively, but may be slightly separated from each other. In the examples illustrated in <FIG>, <FIG>, and <FIG>, the two-groove pulleys <NUM> and <NUM> accommodating the pitch axis rotation are disposed close to the two-groove pulleys <NUM> and <NUM> coaxial with the pitch axis, respectively.

These two-groove pulleys <NUM> and <NUM> for accommodating the pitch axis rotation may not be of the same diameter.

In the embodiment illustrated in <FIG>, the two-groove pulleys <NUM> and <NUM> for accommodating the pitch axis rotation are both rotatably supported by the shaft <NUM> that is coaxial with the pitch axis <NUM>, but may also be supported by shafts that are different from each other. Furthermore, the shaft supporting the two-groove pulley <NUM> and the shaft supporting the two-groove pulley <NUM> may not have the identical axis. In a case where the shaft supporting the two-groove pulley <NUM> and the shaft supporting the two-groove pulley <NUM> are separated, there is an advantage that the layout of the wiring to the tip is easily designed.

As described in section C-<NUM> described above, the two-groove pulley <NUM> is used to change the path of the yaw axis wire <NUM> along the pitch axis <NUM>. Furthermore, as described in section C-<NUM> described above, the two-groove pulley <NUM> is used to change the path of the roll axis wire <NUM> along the pitch axis <NUM>. Both of these two two-groove pulleys <NUM> and <NUM> are supported by the shaft <NUM> coaxial with the pitch axis <NUM>.

These two-groove pulleys <NUM> and <NUM> for accommodating the pitch axis rotation may not be of the same diameter. Furthermore, none of these two-groove pulleys <NUM> and <NUM> for accommodating the pitch axis rotation may have the same diameter as the pulley <NUM> for driving the pitch axis.

Note that the pulley is generally a component with two flanges and a groove drilled between the two flanges along an outer periphery of a disk, and is used for transmission of a tensile force by a wire and change of a path (direction of force) of the wire by being hooked on the groove of the outer periphery of the disk so as not to deviate from a flexible string like a wire. Furthermore, the two-groove pulley is a pulley provided with two grooves on the outer periphery of the disk, but may be configured by coaxially integrating pulleys of one groove.

Referring to <FIG> and the like, the forward path and the backward path of the roll axis wire <NUM> are respectively wound around the set of pulleys 1101a and 1101b rotatably attached around the roll axis <NUM> at both ends of the structure body <NUM> including a hollow cylinder. As a modification example thereof, a two-groove pulley may be attached to one side of the hollow cylindrical structure body <NUM>, and the forward path and the backward path of the roll axis wire <NUM> may be wound around each groove of the two-groove pulley.

The yaw axis <NUM> corresponds to a pan axis that changes the observation direction of the endoscope <NUM> (described above). In order to improve the driving torque around the yaw axis <NUM> (increase the torque), it is preferable to maximize a diameter of the yaw axis pulley <NUM> while keeping the entire structure from the arm to the wrist thin (Specifically, a dimension of the fourth link <NUM> is not increased.

<FIG> illustrates an enlarged structure for realizing the rotational degree of freedom around the yaw axis <NUM> in the tip part of the medical arm device <NUM>. The yaw axis pulley <NUM> is supported on a tip surface of the pitch axis component <NUM> so as to be rotatable coaxially with the yaw axis <NUM>. Furthermore, the two-groove pulley <NUM> and the yaw axis pulley <NUM> are supported on the tip surface of the pitch axis component <NUM> so as to be rotatable coaxially with the yaw axis <NUM>.

On the other hand, a pair of the rerouting pulleys <NUM> and <NUM> for rerouting the pitch axis wire <NUM> between the yaw axis and the pitch axis is supported on the side surface of the pitch axis component <NUM>. The two rerouting pulleys <NUM> and <NUM> having different diameters are disposed on the identical axis in order to smoothly reroute the yaw axis wire <NUM> and wind the yaw axis wire around the yaw axis pulley <NUM> compatible with the two-groove pulley <NUM> rotating around the pitch axis <NUM>. As illustrated in <FIG>, the two rerouting pulleys <NUM> and <NUM> are rotatably supported by a shaft <NUM> constituting the identical axis.

Furthermore, a pair of the rerouting pulleys <NUM> and <NUM> for rerouting the roll axis wire <NUM> between the yaw axis and the pitch axis are supported on side surfaces on an opposite side of the pitch axis component <NUM>. Similarly, the two rerouting pulleys <NUM> and <NUM> having different diameters are disposed on the identical axis in order to smoothly reroute the roll axis wire <NUM> and wind the wire around the two-groove pulley <NUM> which is compatible with the two-groove pulley <NUM> rotating around the pitch axis <NUM>. As illustrated in <FIG>, the two rerouting pulleys <NUM> and <NUM> are rotatably supported by a shaft <NUM> constituting the identical axis.

In a case where a diameter of the yaw axis pulley <NUM> is increased while the entire structure from the arm to the wrist is kept small, the shaft <NUM> or the shaft <NUM> may interfere with the yaw axis pulley <NUM> near the center. Therefore, as illustrated in <FIG>, the diameter of the yaw axis pulley <NUM> may be maximized by forming the central parts of the shaft <NUM> and the shaft <NUM> to be thin or forming the central parts to have a D-cut structure.

In this section N, effects brought by the endoscope holding structure and the wire driving method according to the present disclosure will be summarized.

Therefore, wiring to the tip part can be reduced, and control disturbance can be reduced.

<FIG> illustrates an example of how the medical arm device <NUM> illustrated in <FIG> corresponds to a surgical procedure. In the example illustrated in <FIG>, the medical arm device <NUM> is installed on an opposite side of the surgeon across a surgical bed. Then, the surgeon performs laparoscopic surgery on a patient on the surgical bed while observing the state of a surgical site in an abdominal cavity observed using an endoscope (not illustrated) held at the tip of the medical arm device <NUM>.

As described above, in the medical arm device <NUM> to which the present disclosure is applied, the tip part can realize a small and lightweight structure by intensively disposing orthogonal rotation axes of three degrees of freedom that determine the attitude of the endoscope, and can avoid interference with the surgeon's hand or arm. However, referring to <FIG>, not only the tip part with three degrees of freedom but also the fourth link <NUM> supporting the tip part is in an interference region with the surgeon's hand or arm. Therefore, it can be said that it is desirable to design the fourth link <NUM> with a reduced diameter in order to avoid collision with the surgeon's hand or arm.

<FIG> illustrates an example in which the components of the roll axis <NUM>, the yaw axis <NUM>, and the pitch axis <NUM> are disposed at the tip of the fourth link <NUM>. Furthermore, <FIG> illustrates the structures of the pitch axis wire <NUM>, the yaw axis wire <NUM>, and the roll axis wire <NUM> that tow the components of the pitch axis <NUM>, the yaw axis <NUM>, and the roll axis <NUM>, respectively. <FIG> illustrates an example in which the pitch axis motor <NUM>, the yaw axis motor <NUM>, and the roll axis motor <NUM> are disposed at the root of the fourth link <NUM>.

Here, <FIG> schematically illustrates an appearance configuration of a motor <NUM> used for the pitch axis motor <NUM>, the yaw axis motor <NUM>, and the roll axis motor <NUM>. However, the motors <NUM> to <NUM> are all assumed to be cylindrical electromagnetic actuators. In general, on an output axis of a rotary motor body <NUM>, a brake <NUM>, a speed reducer <NUM>, an encoder <NUM> for detecting a rotational position, a torque sensor <NUM> for detecting an external force acting on the output axis, and a circuit unit <NUM> are disposed. The brake <NUM>, the speed reducer <NUM>, the encoder <NUM>, and the torque sensor <NUM> basically need to be attached in an output axis direction of the motor body <NUM>, and a dimension in the output axis direction of the entire motor <NUM> is expanded. Therefore, the rotary motor <NUM> has a cylindrical shape having a small diameter and long in the output axis direction. Note that the circuit unit <NUM> includes a printed wired board (PWB) on which a circuit chip that performs signal processing of a sensor signal and a drive signal and the like is mounted, but an arrangement position is not particularly limited. As illustrated in <FIG>, in a case where the circuit unit <NUM> is also disposed in the output axis direction of the motor body <NUM>, an outer shape of the motor <NUM> further expands in the output axis direction while maintaining the small diameter.

<FIG> illustrates an example in which the pitch axis motor <NUM>, the yaw axis motor, and the roll axis motor <NUM> that drive the tip part are disposed on the root side of the fourth link <NUM> so that the output axes are all parallel to the pitch axis <NUM>, in other words, aligned in a direction orthogonal to the longitudinal direction of the fourth link <NUM>. In such an arrangement of the motors <NUM> to <NUM>, since a thickness of the fourth link <NUM> is larger than or equal to a dimension in an output axis direction of the motors <NUM> to <NUM>, it is difficult to realize the reduction in diameter of the fourth link.

Therefore, in this section O, an actuator arrangement method is proposed in which at least one of the pitch axis motor <NUM>, the yaw axis motor, or the roll axis motor <NUM> that drive the tip part is disposed with the output axis direction aligned with the longitudinal direction of the fourth link <NUM>, thereby realizing the reduction in diameter of the fourth link <NUM>.

Note that the encoder <NUM> used for the motor <NUM> is assumed to be an absolute encoder. Furthermore, in a case where the motor <NUM> is used for a roll axis, the method of deriving the rotation number from the measurement value of the one-rotation absolute encoder for the output axis (See the section D described above. ) is adopted.

<FIG> illustrates an example in which all three motors <NUM> to <NUM> that drive the respective rotation mechanisms of the tip part having the three rotation mechanisms are disposed with the output axis direction aligned with the longitudinal direction of the fourth link <NUM>. As illustrated in <FIG>, the fourth link <NUM> has a hollow cylindrical shape. Then, the first motor <NUM>, the second motor <NUM>, and the third motor <NUM> are disposed in this order in the hollow cylinder of the fourth link <NUM> from a tip part side toward a root side. However, it is assumed that all of the three motors <NUM> to <NUM> are electromagnetic actuators configured in a cylindrical shape elongated in the output axis direction as illustrated in <FIG>.

As already described with reference to <FIG>, the tip part includes the vertical rotation axis (pitch axis) part <NUM> that swings the endoscope <NUM> in the vertical direction, the left-right rotation axis (yaw axis) part <NUM> that is adjacent to the vertical rotation axis part <NUM>, has a degree of freedom around the left-right rotation axis orthogonal to the vertical rotation axis, and swings the endoscope <NUM> in the left-right direction, and the optical axis rotation axis (roll axis) part <NUM> having a degree of freedom around the optical axis of the endoscope <NUM>. Which axial rotational drive the first motor <NUM>, the second motor <NUM>, and the third motor <NUM> are used is arbitrary. However, in order to reduce the moment of inertia around the joint axis of the third joint part <NUM> of the fourth link <NUM> and reduce an output of the actuator for driving the third joint part <NUM>, it is preferable to dispose the motors in order of weight from the tip part side toward the root side.

Although it is possible to drive the endoscope <NUM> around the roll axis with low torque only by the rotation of the optical axis, high torque is required around the pitch axis in order to drive the entire tip part. Then, assuming that a relationship in which an output of the motor is substantially proportional to a weight of the motor (That is, the weight of the motor increases as the output of the motor increases. ) is established, it is considered preferable to assign the motors in which the first motor <NUM> performs the rotational drive around the roll axis <NUM> of the lens barrel <NUM>, the second motor <NUM> performs the rotational drive around the yaw axis <NUM> of the endoscope <NUM>, and the third motor <NUM> performs the rotational drive around the pitch axis <NUM> of the entire tip part.

Note that, since the structure of the tip part is as described in section C described above, the tip part is not illustrated in <FIG>. Furthermore, in <FIG>, for simplification of the drawing, illustration of a wire transmission mechanism including a wire for transmitting the rotation of each of the motors <NUM> to <NUM> to the tip part side and a pulley for changing the path of the wire and the like is also omitted. By using the wire transmission mechanism for transmitting the rotational force, there is an advantage that the driving force of the actuator can be transmitted with high efficiency and with high accuracy while suppressing the occurrence of backlash. Since the load torque of each rotation mechanism of three degrees of freedom of the tip part is relatively small, it is possible to cover low strength which is a disadvantage of the wire transmission mechanism. Furthermore, it is possible to maximally utilize small and lightweight drive transmission which is an advantage of the wire transmission mechanism. Since each of the motors <NUM> to <NUM> is disposed on the root side of the fourth link <NUM> while being separated from the actual joint position of the tip part, the tip part is reduced in weight, and the torque required to drive each joint can be reduced, which contributes to downsizing of the entire medical arm device <NUM>.

<FIG> illustrate an example in which, out of three motors <NUM> to <NUM> that drive the respective rotation mechanisms of the tip part having the three rotation mechanisms, the first motor <NUM> and the second motor <NUM> are disposed with the output axis direction aligned with the longitudinal direction of the fourth link <NUM>, and the third motor <NUM> on the root side is disposed with the output axis direction oriented in a direction orthogonal to the longitudinal direction of the fourth link <NUM>. <FIG> illustrates a state viewed from a direction of a side surface of the third motor <NUM>, and <FIG> illustrates a state viewed from a direction of a rotation axis of the third motor <NUM>. However, all of the three motors <NUM> to <NUM> are cylindrical electromagnetic actuators elongated in the output axis direction as illustrated in <FIG>.

According to the actuator arrangement example illustrated in <FIG>, a length of a section in which the third motor <NUM> is disposed is shortened to around a diameter of the motor <NUM>. That is, a link length of the fourth link <NUM> can be shortened. However, in the arrangement example of the actuators illustrated in <FIG>, a diameter of a section in which the first motor <NUM> and the second motor <NUM> are disposed in the fourth link <NUM> can be reduced, but the diameter of the section in which the third motor <NUM> is disposed needs to be increased. In a case where an increase in the diameter of the fourth link <NUM> is allowed, it is an effective design. On the other hand, in the case of the actuator arrangement example illustrated in <FIG>, the link length of the fourth link <NUM> is longer than the sum of the dimensions of the motors <NUM> to <NUM> in the output axis direction at the shortest. In short, according to the arrangement example of the actuators illustrated in <FIG>, it is possible to balance the reduction in the diameter of the fourth link <NUM> and the reduction in the link length.

Also in the arrangement example of the actuators illustrated in <FIG>, in order to reduce the inertia moment around the joint axis of the third joint part <NUM> of the fourth link <NUM> and reduce the output of the actuator for driving the third joint part <NUM>, it is preferable to dispose the motors in ascending order of weight from the tip part side toward the root side. Specifically, it is considered preferable to assign the motors in which the first motor <NUM> performs the rotational drive around the roll axis <NUM> of the lens barrel <NUM>, the second motor <NUM> performs the rotational drive around the yaw axis <NUM> of the endoscope <NUM>, and the third motor <NUM> performs the rotational drive around the pitch axis <NUM> of the entire tip part.

Note that, since the structure of the tip part is as described in section C described above, illustration of the tip part is omitted in <FIG>. Furthermore, although a wire transmission mechanism is used to transmit the rotation of each of the motors <NUM> to <NUM> to the tip part side, the wire transmission mechanism is not illustrated in <FIG> for simplification of the drawings. By using the wire transmission mechanism, it is possible to transmit the rotation of each of the motors <NUM> to <NUM> with high accuracy by suppressing the occurrence of backlash with high efficiency of the driving force of the actuator. Since the load torque of each rotation mechanism of three degrees of freedom of the tip part is relatively small, it is possible to cover low strength which is a disadvantage of the wire transmission mechanism. Furthermore, it is possible to maximally utilize small and lightweight drive transmission which is an advantage of the wire transmission mechanism. Since each of the motors <NUM> to <NUM> is disposed on the root side of the fourth link <NUM> while being separated from the actual joint position of the tip part, the tip part is reduced in weight, and the torque required for the rotational drive of the fourth link <NUM> can be reduced, which contributes to downsizing of the entire medical arm device <NUM>.

<FIG> illustrate an example in which, among three motors <NUM> to <NUM> that drive the respective rotation mechanisms at the tip part having the three rotation mechanisms, the motor <NUM> is disposed with the output axis direction aligned with the longitudinal direction of the fourth link <NUM>, while the second motor <NUM> and the third motor <NUM> are disposed with the output axis direction oriented in a direction orthogonal to the longitudinal direction of the fourth link <NUM>. <FIG> illustrates a state viewed from a direction of side surfaces of the second motor <NUM> and the third motor <NUM>, and <FIG> illustrates a state viewed from a direction of rotation axes of the second motor <NUM> and the third motor <NUM>. However, all of the three motors <NUM> to <NUM> are cylindrical electromagnetic actuators elongated in the output axis direction as illustrated in <FIG>.

According to the arrangement example of the actuators illustrated in <FIG>, since a length of a section in which the second motor <NUM> and the third motor <NUM> are disposed is shortened to about a diameter of each of the motors <NUM> and <NUM>, it is possible to further shorten the link length of the fourth link <NUM> as compared with the arrangement example of the actuators illustrated in <FIG> while forming a reduced diameter part of the fourth link <NUM>. In a case where an increase in the diameter of the fourth link <NUM> is allowed, it is an effective design. In short, according to the arrangement example of the actuators illustrated in <FIG>, it is possible to balance the reduction in the diameter of the fourth link <NUM> and the reduction in the link length.

Note that, also in the arrangement example of the actuators illustrated in <FIG>, in order to reduce the moment of inertia around the joint axis of the third joint part <NUM> of the fourth link <NUM> and reduce the output of the actuator for driving the third joint part <NUM>, it is preferable to dispose the motors in ascending order of weight from the tip part side toward the root side. Specifically, it is considered preferable to assign the motors in which the first motor <NUM> performs the rotational drive around the roll axis <NUM> of the lens barrel <NUM>, the second motor <NUM> performs the rotational drive around the yaw axis <NUM> of the endoscope <NUM>, and the third motor <NUM> performs the rotational drive around the pitch axis <NUM> of the entire tip part.

<FIG> illustrate an example in which all three motors <NUM> to <NUM> that drive the respective rotation mechanisms at the tip part having the three rotation mechanisms are disposed with the output axis direction aligned with the longitudinal direction of the fourth link <NUM>. <FIG> illustrates a state viewed from a direction of side surfaces of the motors <NUM> to <NUM>, and <FIG> illustrates a state viewed from a direction of rotation axes of the motors <NUM> to <NUM>. However, all of the three motors <NUM> to <NUM> are cylindrical electromagnetic actuators elongated in the output axis direction as illustrated in <FIG>.

A difference between the arrangement example of the actuators illustrated in <FIG> and the arrangement example of the actuators illustrated in <FIG> is that a part of a section on the tip part side where the three motors <NUM> to <NUM> are not disposed in the fourth link <NUM> is reduced in diameter.

Note that, since the structure of the tip part is as described in section C described above, illustration of the tip part is omitted in <FIG>. Furthermore, although a wire transmission mechanism is used to transmit the rotation of each of the motors <NUM> to <NUM> to the tip part side, the wire transmission mechanism is not illustrated in <FIG> for simplification of the drawings.

<FIG> and <FIG> illustrate an example in which, out of three motors <NUM> to <NUM> that drive the respective rotation mechanisms at the tip part having the three rotation mechanisms, the first motor <NUM> and the second motor <NUM> are disposed on the fourth link <NUM> with the output axis direction aligned with the longitudinal direction of the fourth link <NUM>, while the third motor <NUM> is disposed in an outside (on the root side) of the fourth link <NUM> with the output axis direction oriented in a direction orthogonal to the longitudinal direction of the fourth link <NUM>. <FIG> illustrates a state viewed from a direction of a side surface of the third motor <NUM>, and <FIG> illustrates a state viewed from a direction of a rotation axis of the third motor <NUM>. However, all of the three motors <NUM> to <NUM> are cylindrical electromagnetic actuators elongated in the output axis direction as illustrated in <FIG>.

Note that, since the structure of the tip part is as described in section C described above, illustration of the tip part is omitted in <FIG> and <FIG>. Furthermore, although a wire transmission mechanism is used to transmit the rotation of each of the motors <NUM> to <NUM> to the tip part side, the wire transmission mechanism is not illustrated in <FIG> and <FIG> for simplification of the drawings.

The arrangement example of the actuators illustrated in <FIG> and <FIG> is common to the arrangement example of the actuators illustrated in <FIG> in that the first motor <NUM> and the second motor <NUM> are disposed with the output axis direction aligned with the longitudinal direction of the fourth link <NUM>, while the third motor <NUM> on the root side is disposed with the output axis direction oriented in a direction orthogonal to the longitudinal direction of the fourth link <NUM>. However, the actuator arrangement example illustrated in <FIG> and <FIG> is different from the example illustrated in <FIG> in that the third motor <NUM> is disposed outside the fourth link <NUM>. In the arrangement example of the actuators illustrated in <FIG>, the third motor <NUM> is disposed in the fourth link <NUM>. By disposing the third motor <NUM> outside the fourth link <NUM>, compactness of the fourth link <NUM> can be realized.

Specifically, the third motor <NUM> is disposed in a rotation mechanism unit on the root side of the fourth link <NUM>. Here, the rotation mechanism unit on the root side of the fourth link <NUM> corresponds to the third joint part <NUM> in <FIG>. The third joint part <NUM> is a rotation mechanism that rotates the fourth link <NUM> around the vertical rotation axis (alternatively, the pitch axis) on the root side. By disposing the third motor <NUM> outward from the root side of the fourth link <NUM>, the torque required for the rotational drive of the fourth link <NUM> is further reduced, which contributes to further downsizing of the entire medical arm device <NUM>.

In a case where the third motor <NUM> is disposed in the third joint part <NUM>, a motor <NUM> for rotating the fourth link <NUM> around the pitch axis cannot be disposed in the third joint part <NUM>. Therefore, in the arrangement example of the actuators illustrated in <FIG> and <FIG>, the motor <NUM> for driving the third joint part <NUM> is disposed outside the third joint part <NUM> (on an opposite side of the fourth link <NUM>). Then, a rotational force of the motor <NUM> is transmitted to the third joint part <NUM> accommodating the third motor <NUM> using a steel belt <NUM> to realize the rotation of the fourth link <NUM> around the pitch axis.

Referring to <FIG> and <FIG>, the third joint part <NUM> has a hollow cylindrical structure having a central axis in the pitch axis direction, and is joined and integrated with an inner wall of the fourth link <NUM>. On the other hand, the third motor <NUM> and the motor <NUM> are fixed to a frame of the third link <NUM>. The third motor <NUM> is disposed in the hollow cylinder of the third joint part <NUM> such that the rotation axis coincides with a joint axis of the third joint part <NUM>, and is rotatably supported around the joint axis via a bearing.

An output axis pulley <NUM> of the motor <NUM> includes a hollow cylinder that covers an outer periphery of the motor <NUM>. Then, the steel belt <NUM> is wound around the third joint part <NUM> and the output axis pulley <NUM>. Therefore, the rotation of the motor <NUM> is transmitted to the third joint axis <NUM> via the steel belt <NUM>, and the fourth link <NUM> can be rotated around the joint axis of the third joint part <NUM> (around the pitch axis or around the vertical rotation axis). At this time, since the third motor <NUM> is rotatably supported in the hollow cylinder of the third joint part <NUM> via a bearing, the rotational operation of the motor <NUM> is not transmitted to the third motor <NUM>. Furthermore, by using the steel belt <NUM> including a metal plate such as stainless steel for the transmission mechanism of the rotation of the motor <NUM>, it is possible to perform drive transmission with high strength, wide movable range, high efficiency, and high accuracy without rattling.

<FIG> and <FIG> illustrate an example in which all three motors <NUM> to <NUM> that drive the respective rotation mechanisms of the tip part having the three rotation mechanisms are disposed on the fourth link <NUM> with the output axis direction aligned with the longitudinal direction of the fourth link <NUM>, and a motor <NUM> for driving the third joint part <NUM> is disposed outside the third joint part <NUM> (on an opposite side of the fourth link <NUM>). <FIG> illustrates a state viewed from a direction of a side surface of the motor <NUM>, and <FIG> illustrates a state viewed from a direction of a rotation axis of the motor <NUM>. However, all of the three motors <NUM> to <NUM> are cylindrical electromagnetic actuators elongated in the output axis direction as illustrated in <FIG>.

The arrangement example of the actuators illustrated in <FIG> and <FIG> is common to the arrangement example of the actuators illustrated in <FIG> and <FIG> in that the motor <NUM> for driving the third joint part <NUM> is disposed outside the third joint part <NUM> (on an opposite side of the fourth link <NUM>). However, the arrangement example of the actuators illustrated in <FIG> and <FIG> is different from the example illustrated in <FIG> and <FIG> in that the first to third motors <NUM> to <NUM> are disposed in the fourth link <NUM> and none of the actuators is disposed in the third joint part <NUM>. In the actuator arrangement example illustrated in <FIG> and <FIG>, the entire fourth link <NUM> can be reduced in diameter by disposing all the motors <NUM> to <NUM> on the fourth link <NUM> with the output axis direction aligned with the longitudinal direction of the fourth link <NUM>. Furthermore, by not disposing any motor in the third joint part <NUM>, the third joint part <NUM> is downsized, so that a small diameter part of the fourth link <NUM> can be secured in a long section.

The third joint part <NUM> is a rotation mechanism that rotates the fourth link <NUM> around the vertical rotation axis (alternatively, the pitch axis) on the root side (described above). Referring to <FIG> and <FIG>, the third joint part <NUM> has a hollow cylindrical structure having a central axis in the pitch axis direction, and is joined and integrated with an inner wall of the fourth link <NUM>. Furthermore, the third joint part <NUM> is supported by the third link <NUM> via a bearing disposed in the hollow cylinder so as to be rotatable around the joint axis.

An output axis pulley <NUM> of the motor <NUM> includes a hollow cylinder that covers an outer periphery of the motor <NUM>. Then, a steel belt <NUM> is wound around the third joint part <NUM> and the output axis pulley <NUM>. Therefore, the rotation of the motor <NUM> is transmitted to the third joint axis <NUM> via the steel belt <NUM>, and the fourth link <NUM> can be rotated around the joint axis of the third joint part <NUM> (around the pitch axis or around the vertical rotation axis). Furthermore, by using the steel belt <NUM> including a metal plate such as stainless steel for the transmission mechanism of the rotation of the motor <NUM>, it is possible to perform drive transmission with high strength, wide movable range, high efficiency, and high accuracy without rattling.

As described in sections O-<NUM> to O-<NUM> described above, in a case where the motors for each axis are disposed on the root side of the fourth link <NUM> apart from the roll axis, the yaw axis, and the peach axis of the tip part, a transmission mechanism for transmitting a rotational force of each of the motors to the tip part is required. In the present disclosure, by using a wire transmission mechanism for transmitting the rotational force, a driving force of the actuator is transmitted with high efficiency and with high accuracy while suppressing the occurrence of backlash. Since the load torque of each rotation mechanism of three degrees of freedom of the tip part is relatively small, it is possible to cover low strength which is a disadvantage of the wire transmission mechanism. Furthermore, it is possible to maximally utilize small and lightweight drive transmission which is an advantage of the wire transmission mechanism.

In this section O-<NUM>, an arrangement example of a wire drive mechanism that transmits the rotational force of each of the motors to the tip part in the fourth link <NUM> in the arrangements of each of the motors described in sections O-<NUM> to O-<NUM> described above will be described. Basically, a rotational force of the motor is extracted using a wire wound around the output axis pulley attached to an output axis of the motor. Then, the position and direction of the pitch axis or the roll axis of the wire are changed appropriately using the rerouting pulley to avoid interference with other motors and other components existing between the output axis pulley and the tip part, and the motor and the target component are connected by the wire.

<FIG> illustrate a configuration example of a wire transmission mechanism in a case where all three motors <NUM> to <NUM> described in section O-<NUM> described above are disposed with the output axis direction aligned with the longitudinal direction of the fourth link <NUM>. However, in <FIG>, a rotational position of the fourth link <NUM> around the longitudinal axis is changed by <NUM> degrees.

A position of a wire <NUM> wound around an output axis pulley <NUM> of the first motor <NUM> in the fourth link <NUM> is adjusted via a rerouting pulley <NUM> on a forward path side and a rerouting pulley <NUM> on a backward path side, and is directed toward the tip part side. Furthermore, a position of a wire <NUM> wound around an output axis pulley <NUM> of the second motor <NUM> in the fourth link <NUM> is adjusted via a rerouting pulley <NUM> on a forward path side and a rerouting pulley <NUM> on a backward path side. Here, the wire <NUM> is disposed so as not to interfere with the wire <NUM> by changing the rotational position of the rerouting pulleys <NUM> and <NUM> around the longitudinal axis only by <NUM> degrees with respect to the rerouting pulleys <NUM> and <NUM>. Furthermore, a position of a wire <NUM> wound around an output axis pulley <NUM> of the third motor <NUM> in the fourth link <NUM> is adjusted via a rerouting pulley <NUM> on a forward path side and a rerouting pulley <NUM> on a backward path side. Here, the rerouting pulleys <NUM> and <NUM> are disposed at the same rotational position around the longitudinal axis as the rerouting pulleys <NUM> and <NUM>, and at different positions in a radial direction (or width direction) the wire <NUM> is disposed so as not to interfere with the wire <NUM>.

Note that, although the configuration of the tip part side of each of the wires <NUM>, <NUM>, and <NUM> is not illustrated, it is assumed that a rerouting pulley or the like is appropriately used to match the arrangements of the wires illustrated in <FIG>, for example.

<FIG> illustrate a configuration example of a wire transmission mechanism in a case where, out of three motors <NUM> to <NUM> described in section O -<NUM> described above, the first motor <NUM> and the second motor <NUM> are disposed with the output axis direction aligned with the longitudinal direction of the fourth link <NUM>, and the third motor <NUM> on the root side is disposed with the output axis direction oriented in a direction orthogonal to the longitudinal direction of the fourth link <NUM>. However, in <FIG>, a rotational position of the fourth link <NUM> around the longitudinal axis is changed by <NUM> degrees.

A position of a wire <NUM> wound around an output axis pulley <NUM> of the first motor <NUM> in the fourth link <NUM> is adjusted via a rerouting pulley <NUM> on a forward path side and a rerouting pulley <NUM> on a backward path side, and is directed toward the tip part side. Furthermore, a position of a wire <NUM> wound around an output axis pulley <NUM> of the second motor <NUM> in the fourth link <NUM> is adjusted via a rerouting pulley <NUM> on a forward path side and a rerouting pulley <NUM> on a backward path side. Similarly to the example illustrated in <FIG>, the wire <NUM> is disposed so as not to interfere with the wire <NUM> by changing the rotational position of the rerouting pulleys <NUM> and <NUM> around the longitudinal axis only by <NUM> degrees with respect to the rerouting pulleys <NUM> and <NUM>. Furthermore, a wire <NUM> wound around an output axis pulley <NUM> of the third motor <NUM> can be wired in the fourth link <NUM> so as to avoid interference with the first motor <NUM> disposed on the tip side, the second motor <NUM>, each of the wires <NUM> and <NUM>, and the like. Of course, a pulley (not illustrated) for changing the path or adjusting the position may be further disposed on at least one of a forward path side or a backward path side of the wire <NUM>.

Note that, although a configuration of the tip part side of each of the wires <NUM>, <NUM>, and <NUM> is not illustrated, it is assumed that a rerouting pulley or the like is appropriately used to match the arrangements of the wires illustrated in <FIG>, for example.

<FIG> illustrate a configuration example of a wire transmission mechanism in a case where, out of three motors <NUM> to <NUM> described in section O-<NUM> described above, the first motor <NUM> is disposed with the output axis direction aligned with the longitudinal direction of the fourth link <NUM>, and the second motor <NUM> and the third motor <NUM> are disposed with the output axis direction oriented in a direction orthogonal to the longitudinal direction of the fourth link <NUM>. However, in <FIG>, a rotational position of the fourth link <NUM> around the longitudinal axis is changed by <NUM> degrees.

A position of a wire <NUM> wound around an output axis pulley <NUM> of the first motor <NUM> in the fourth link <NUM> is adjusted via a rerouting pulley <NUM> on a forward path side and a rerouting pulley <NUM> on a backward path side, and is directed toward the tip part side. Furthermore, an output axis of the second motor <NUM> is orthogonal to the longitudinal direction of the fourth link <NUM>, and an output axis pulley <NUM> of the second motor <NUM> is disposed in a direction opposite to the wire <NUM>. Therefore, a wire <NUM> wound around the output axis pulley <NUM> can be wired in the fourth link <NUM> so as to avoid interference with the first motor <NUM>, the wire <NUM>, and the like disposed on the tip side. Of course, a pulley (not illustrated) for changing the path or adjusting the position may be further disposed on at least one of a forward path side or a backward path side of the wire <NUM>. Furthermore, similarly to the second motor <NUM>, an output axis of the third motor <NUM> is orthogonal to the longitudinal direction of the fourth link <NUM>, and an output axis pulley <NUM> of the third motor <NUM> is disposed in the same direction as the output axis pulley <NUM> of the second motor <NUM>. As can be seen from <FIG>, a position of the output axis pulley <NUM> is shifted in a direction orthogonal to the longitudinal direction of the fourth link <NUM> so as not to overlap with the output axis pulley <NUM>. Therefore, the wire <NUM> wound around the output axis pulley <NUM> can be wired in the fourth link <NUM> so as to avoid interference with the first motor <NUM> disposed on the tip side, the second motor <NUM>, each of the wires <NUM> and <NUM>, and the like. Of course, a pulley (not illustrated) for changing the path or adjusting the position may be further disposed on at least one of a forward path side or a backward path side of the wire <NUM>.

The present disclosure has been described in detail above with reference to specific embodiments. However, it is obvious that those skilled in the art can make modifications and substitutions of the embodiments without departing from the gist of the present disclosure.

In the present specification, the embodiments in which the present disclosure is applied to a medical arm device that supports an endoscope have been mainly described, but the gist of the present disclosure is not limited thereto. The present disclosure can be similarly applied to a medical arm device that supports a medical instrument other than the endoscope, for example, forceps, a pneumoperitoneum tube, an energy treatment tool, tweezers, a retractor, or the like at the tip, and the attitude of the medical instrument to be supported can be determined without backlash in three orthogonal degrees of freedom.

Claim 1:
A medical arm device (<NUM>) comprising:
a first arm part including a tip part that holds a medical instrument (<NUM>) and a link (<NUM>) that supports the tip part; and
a second arm part that supports the first arm part, wherein
the tip part includes
a structure in which three rotation axes are disposed in order of a rotation axis (<NUM>) around a longitudinal axis of the medical instrument (<NUM>), a yaw axis (<NUM>) that rotates the medical instrument (<NUM>) left and right with respect to a tip of the link (<NUM>), and a pitch axis (<NUM>) that rotates the medical instrument (<NUM>) up and down with respect to the tip of the link (<NUM>) in order from a most tip part, and
a first wire (<NUM>) for rotation transmission of the yaw axis (<NUM>), a second wire (<NUM>) for rotation transmission of the roll axis (<NUM>), a first rerouting pulley that reroutes the first wire (<NUM>) between the pitch axis (<NUM>) and the yaw axis (<NUM>), a second rerouting pulley that reroutes the second wire (<NUM>) between the pitch axis (<NUM>) and the yaw axis (<NUM>), and a third rerouting pulley that reroutes the second wire (<NUM>) between the yaw axis (<NUM>) and the roll axis (<NUM>) are disposed on the link (<NUM>);
wherein at least one of the first rerouting pulley or the second rerouting pulley includes a set of rerouting pulleys having different diameters disposed on an identical axis on an opposite side of a structure body rotating around the pitch axis (<NUM>); and
wherein the medical arm device (<NUM>) further comprises at least one of a third wire for rotation transmission of the pitch axis, a link mechanism, a gear mechanism, or a motor that directly rotates the pitch axis (<NUM>) .