JPS598516B2 - Multisegmented funicular apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multi-section functional cord device having a cord-like multi-section structure, each section of which is flexible and actively bends.

A multi-segmented cord-shaped device is a device that can form any posture and shape, similar to the body trunk of a snake in the biological world.For example, it can be used for inspections during the service life of nuclear reactors, inspections of the inside of complex devices, and flade inspections of water turbines. It is used as the arm of a pot for various examinations, and can also be applied as an active endoscope.

Such a multi-joint functional body requires each joint to be sufficiently lightweight, and requires a high-output and robust drive device, and a fully practical device has not yet been realized.

However, as this type of device, the following can be considered, for example.

That is, as shown in FIG.
b... are arranged in series, and each node Il
a, Ilb... are connected sequentially by actuators 12a, 12b... for bending motion, and the bending directions of the actuators 12a, 12b... are sequentially different, for example, by 90 degrees, It is something that enables three-dimensional movement of the funicular body. However, such devices have a low output-to-weight ratio and can only realize actuators that can only support their own weight, making it virtually impossible to construct robots that perform inspections or other tasks. Have difficulty. 5. Also, as shown in FIG. 2, a plurality of disk bodies 13a, 13b..., joints 14a, 14b... attached to their respective central shafts are sequentially connected by universal joints 15a, 15b..., It is made into a funicular body that can move in three dimensions.

The plurality of disc bodies 13a, 13b... are connected to each other by a plurality of pneumatic cylinders 16a, 16b... like bellows arranged axially symmetrically, and the respective pneumatic cylinders 16a, 16b... ...for pipe 1
Piping Ta, 17b..., cylinders 16a, 16b
. . . to control the intake and exhaust of air, and to enable bending operations using the universal joints 15a, 15b, . . . as fulcrums. Therefore, if this is done, there will be no mechanical interference for, for example, node drive, but the multiple disc bodies 13
It is necessary to install a plurality of small pneumatic cylinders 16a, 16b, . . . between each of the cylinders 16a, 13b, . In addition, for each of the pneumatic cylinders 16a, 16b, which are required in large numbers, pipes 17a, 1rb, 1rb, etc. for pneumatic pressure transmission are provided.
Since it is necessary to install piping for each of them, the volume for that purpose becomes large, and it becomes difficult to miniaturize and construct a multi-sectioned cable-like body. This invention was made in view of the above points, and it is possible to effectively and independently control the bending of each node arranged in a large number in the form of a cord, and to make it sufficiently simple, lightweight and robust. , it is an object of the present invention to provide a multi-segment functional cord-like device having high bending motility.

An embodiment of the present invention will be described below with reference to the drawings.

The cable device 20 according to the present invention is configured to be bendable as shown in FIG. 3, and a working device 21 for performing inspection and other operations is attached to the distal end thereof. The proximal end portion of the arm-shaped cable device 20 is attached to a control drive mechanism 22, and the cable device 20 makes arbitrary bending movements based on an operation command from this mechanism 22. FIG. 4 shows a section of a part of the cable-like device 20, which has a plurality of flanges 23a, 23b, . . . .

The flanges 23a, 23b, . . . are each formed into a ring shape having a hollow portion.
Coil springs 24a, 24b, .
will be connected sequentially. In this case, each of the coil springs 24a, 24b, . . . acts elastically to push open the adjacent flanges, and may be constituted by an elastic body such as a bellows that acts in the same way. The coil springs 24a, 24b... portions are
The plurality of nodes of the cord-like device 20 are configured to be able to bend. The bending motion mechanism at each node of this cord-like device is as shown in the node between flanges 23a and 23b, with respect to flange 23a corresponding to the distal direction.
For example, three inner wires 25a to 25c are connected.

In this case, the inner wires 25a to 25c are connected to the flange 23a on a concentric circle close to the outer periphery of the flange 23a, and are fixed at intervals of 120 degrees, which are equiangularly symmetrical positions with respect to the central axis. The inner wires 25a to 25c are inserted into hollow pipe-shaped outer wires 26a to 26c led out through the hollow portion of each flange in the proximal direction of the cable device 20, respectively. The tip is attached to the outer periphery of the flange 23b on the base end side of the joint represented above.
Install and fix at 20 degree intervals. Then, an inner wire 25 led out from the base end side of the outer wires 26a to 26c.
By changing and adjusting the withdrawal amount L of a to 25c,
Inner wire 25a~ between flanges 23a and 23b
By changing the length of the flange 25c, the bending angle formed between the flanges 23a and 23e can be variably set. Although the mechanism related to the inner wire and the outer wire for adjusting the bending angle is omitted in the figure, it is provided for each flange 23a, 23b, etc., and for example, depending on the number of flanges 23a, 23b. In the case of n pieces, 3n outer wires are taken out from the proximal end of the cable device 20 and guided into the control drive mechanism 22.

Inside the control drive mechanism 22, an inner wire tensioning mechanism is provided corresponding to each of the 3n inner and outer wires.

FIG. 5 shows one of the tension mechanisms 27, in which a sliding body 28 is integrally attached to the tip of the inner wire 25. As shown by arrow 30 within block body 29, this sliding body 28 is provided with a gear mechanism, as appropriate.
Alternatively, it may be slid and moved by a magnetic mechanism. Here, the tip of the outer wire 26 is fixedly connected to the block body 29 so that L shown in FIG. 4 can be variably adjusted. By driving the wires corresponding to each node in a coordinated manner, the arm-shaped cable device 20 can take any bending posture. In this case, the force generated within the tension mechanism 27 of the drive mechanism 22 is
This acts as a relative force between the outer wire 26 and the inner wire 25, and even if a large force is propagated, the outer wire 26 is flexible and the wires do not pass through until the end of the wire reaches the node to be driven. There is no way to prevent movement of the proximal segment.

In order to further provide mechanical non-interference with each node by the wire, the tension mechanism 27 itself for each wire is installed on the rail 31 via a pulley 32, and the movement of the outer wire 26 is controlled by the tension mechanism 27 itself. It is effective to allow the mechanism 27 to follow freely.

Next, the driving principle of the mechanism surrounding the inner wire 26 and outer wire 27 will be explained.

Now, in order to bend the first node by a bending angle θi in an arbitrary bending direction τi, the length Tij of the jth (j=1 to 3) inner wire of the first node is . ．． ．． 2. ．． ．．
ρ1 tij=TiO−γIsin(endedπj+τi)Sini
And it is sufficient.

However, at this time, the length of the central axis of the first node is maintained at TiO.

Moreover, γi indicates the distance from the wire Tij to the center of the corresponding flange. FIG. 6 shows another example of the structure of the tensioning mechanism 27, which is constructed so that the inner wire 25 is tensioned by a spool 33. 34 is a block for connecting and fixing the base end portion of the outer wire 26.

The spool 33 may be rotated by finely adjusting the amount of rotation angle using, for example, a pulse motor. In such a drive mechanism 22, a coil spring 24 at each node is used.
A, 24b...A state occurs in which the three inner wires 25a to 25c are constantly attracted against the respective stretching forces. Therefore, in the tension mechanism 27, the inner wires 25a to 25a are always under the tension of this coil spring.
25c should be indexed. For this reason, the direction of expanding the coil spring at the joint can be easily changed, but conversely, in order to compress and bend the joint, a large tensile driving force is required. Therefore, it is necessary to add a compensating spring to the tension mechanism 27 to counteract this constantly acting tension.

Of course, if the tension mechanism 27 is strong enough to withstand the tension force of the coil spring, this compensating spring is not necessary, and in this way it is possible to have a simpler configuration. However, if a compact mechanism is used to drive the cable-like arm portion once, and a large number of nodes are set, and a large number of tension mechanisms are required, it is effective to install a compensation spring mechanism. The compensation spring will be discussed as follows. In other words, the displacement x of the inner wire resisting the coil spring and the tension F generated in the wire
The relationship with is shown in FIG. In other words, according to Hook's law, the tension F increases linearly with the displacement x. Here, the length of the inner wire is varied between X1 and X2, usually X. The length shall be kept at . At this time, if we insert a compensation spring that resists the coil spring, the characteristics of this compensation spring are shown in Figure 8A.
As shown in , if the tension mechanism 27 generates a force Fc having negative spring characteristics at least in the section from X1 to X2, then the tension mechanism 27 . Since the force that should be generated is "F-Fc", the displacement
In the range from 1 to X2, the force that should be generated can theoretically be zero. Of course, at this time, a force is required to resist the friction between the inner wire and the outer wire, but even so, by introducing this compensation spring, it is possible to significantly reduce the output that should be generated by the tension mechanism 27. Become. A spring mechanism with such negative characteristics is
For example, in the case of linear drive as shown in FIG. 5, rotary casters 36a to 36d are provided at the tips of the two links 35a and 35b as shown in FIG. It is preferable to use a mechanism that applies force in the direction.

Further, when the inner wire 25 is tension-controlled using a spool as shown in FIG. 6, a compensation spring may be used to cancel the rotational drive moment of the spool 33.

FIG. 10 shows a simplified configuration example in which the inner wire 25 is wound around an eccentric circular pulley 39 of the rotating shaft 38, and a simple linear compensation spring 40 is connected to the end of the wire. It is. Although the pulley 39 is omitted in the figure, a gear provided coaxially with the rotating shaft 3811C is rotated by a screw rotated by a pulse motor or the like. In other words, the drive torque that should be generated on the eccentric rotating shaft 38 is balanced against the tension caused by the joints and reduced.

FIG. 11 shows the relationship between the generated torque C after compensation from the characteristic A due to the coil spring and the characteristic B due to the compensation spring in the case of the mechanism as described above.

This method is mechanically very simple, and actual measurement data confirmed that the output increases about five times that of the case without compensation. Alternatively, as shown in FIG. 12, a spool 41 whose radius decreases with rotation may be used, and a compensation spring 43 may be attached to the rotating shaft 42 of this spool 41.

The rotational moment of the spool 41 to resist the coil spring of the Tlll joint is approximately constant because it is equal to "tension x spool radius". If the reduction rate of the radius with respect to the rotation angle of the spool 41 is increased,
As the spool 41 rotates, the rotational moment tends to decrease. Therefore, if the compensating spring 43 is configured as a spiral spring as shown in the figure to generate a substantially constant rotational force, it is possible to compensate one drive torque generated at the rotating shaft 42 portion to substantially zero. As described above, according to the present invention, a cable-like arm is formed by an elastic body made of a coil spring, a bellows, etc. and a flange, and the bending state of each joint made of a combination of an inner wire and an outer wire is variable. The present invention provides a cord-like device capable of controlling multi-section functions, which is driven, has very good effective operability, and is miniaturized.

Of course, the working device 21 at the tip of the cable arm can also be remotely controlled by the same wire mechanism as described above. The mechanism that was actually tested consisted of 8 sections:
The outer diameter of the coil spring is 68mm, the basic total length is 800mm.
rm, and the maximum bending angle of one node is 60 degrees.

In this case, the center part of the ring-shaped flange has a diameter of 40 mm.
There is a hollow part of approximately m length, and it is easy to guide the wire for driving the tip working part or the endoscope 4, etc. By pulling the entire wire sufficiently and driving the coil spring section in a stiff state, it is possible to perform a cantilever-like floating motion.

In addition, when the wire is loosened, it can exhibit the characteristic of bending the body at the bending part while resting its own weight, and this allows it to change between active and passive positions in narrow spaces. The operation can be realized.
In this case, each tensioning mechanism is powered by a DC motor with a power of 2.5W,
A microcomputer was used to control each node.

It is also effective to set the elasticity of the coil spring, which is an elastic body of each node, to be smaller as it approaches the tip where the load is reduced. Devices configured in this way can be sufficiently miniaturized, so they can be used, for example, by actively deforming gastrocameras and colonoscopes according to the shape of internal organs and inserting them deep into the body. Become. At this time, the degree of freedom of each joint is not completely constrained by the wire, and even if it normally maintains its posture, it is a passive device that deforms in response to external loads depending on the strength of the elastic body that makes up the joint. It has flexibility. For example, in the case of applications such as endoscopes that enter body cavities, this moderate automatic deformation characteristic effectively increases adaptability and cooperates with its own active bending characteristics. Become. In addition, it can exhibit an effective property of entering the living body with good consistency. This passive flexibility can be significantly reduced if the tension in the wire is increased and the elastic bodies forming the nodes are used in a compressed state.

Also in this case, due to the action of the compensation spring,
The driving power is sufficiently small. As a matter of course, it can effectively function as a robot device for various inspections, operations, etc. as described above.

In the embodiment, the flange that connects each node of the elastic body is formed into a ring shape, and wires and the like are guided to the control drive mechanism through the hollow part of the flange.

However, by forming guide holes corresponding to each wire on the outer circumference of the flange to guide the inner and outer wires to the drive mechanism, the hollow part can be used more effectively and can be used for various inspections and work. information transmission system, etc. can be effectively accommodated.

[Brief explanation of the drawing]

1 and 2 are diagrams each explaining a cable-like device that has been considered up to now, FIG. 3 is a diagram schematically showing a cable-like device according to an embodiment of the present invention, and FIG. 4 is a diagram illustrating the above-mentioned device. FIGS. 5 and 6 are views showing an example of the wire tensioning mechanism in the above device, and FIGS.
8 and 8 are diagrams each explaining the characteristics of the compensation spring included in the tension mechanism, FIG. 9 is a diagram explaining an example of the configuration of the compensation spring, and FIG. 10 is a diagram showing another example of the tension mechanism. FIG. 11 is a diagram illustrating the compensation characteristics of the compensation spring, and FIG. 12 is a diagram illustrating still another example of the tension mechanism. 20... Cable device, 21... Working device,
22...Control drive mechanism, 23a, 23b...
...Flange, 24a, 24b...Coil spring, 25, 25a-25c...Inner wire, 26, 26a-26c...Outer wire, 27...・Tension mechanism, 33, 39, 41...
... Spool, 37, 40, 42 ... Compensation spring.

Claims (1)

[Scope of Claims] 1. A plurality of flanges that are sequentially connected via elastic bodies to form a cord-like body, a large number of inner wires connected to at least three axially symmetrical points of each of the plurality of flanges, and the above-mentioned Each of the inner wires is guided by the inner wire connected to each of the plurality of flanges, and the outer wire is connected to the adjacent flange on the proximal end side. A multi-section functional cord-like device characterized by being tension-controlled. 2. The device according to claim 1, wherein each of the flanges is formed into a ring shape, and the outer wire is guided to the base end of the cable body through the central hole thereof. 3. Claims in which each of the flanges is formed into a ring shape, and a through hole is formed in the ring portion through which each of the outer wires is inserted, and the outer wire is guided to the base end through each of the through holes. 1st
Apparatus described in section. 4. The device according to claim 1, wherein each of the elastic bodies connecting each of the plurality of flanges is a coil spring that connects each end to an adjacent flange. 5 The elastic body that connects the plurality of flanges is
2. The device according to claim 1, comprising a bellows.