JPH06209945A - Flexible pipe device having a multiple degree of freedom - Google Patents

Abstract

PURPOSE:To provide a small-sized flexible pipe device having a multiple degree of freedom which independently controls a plurality of actuators installed on each of a plurality of joints, with the less wiring, and permits the smooth movement. CONSTITUTION:A flexible pipe device having a multiple degree of freedom which consists of a plurality of actuators A1,... for curving operation which are installed in a flexible pipe and a plurality of driving means 4 for driving the actuators A1,... is equipped with a control signal line 8 which is installed in the flexible pipe and transmits one analog control signal, one synchronous signal line 7, and a plurality of selecting means for selectively inputting the analog control signal transmitted from the control signal line 8 into the driving means 4,....

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible tube device having multiple degrees of freedom, which is inserted into a complicated conduit and repairs the inside of the conduit or performs operations such as surgery.

[0002]

2. Description of the Related Art Conventionally, there have been known endoscopes and treatment tools for inserting a long insertion portion into a duct and observing or repairing the duct or performing a procedure such as surgery on an affected part. There is. However, when this is used by inserting it into a complicated conduit, it becomes more difficult to insert a long insertion part. Therefore, a multi-degree-of-freedom manipulator in which the long insertion part is divided into a plurality of parts and each part is curvedly driven by a shape memory alloy (SMA) so as to be suitable for insertion into a complicated conduit, is provided. It has been proposed (see JP-A-63-136014). In this, a method of independently controlling each actuator of a multi-joint manipulator and further performing feedback control is shown.

[0003]

However, there are many problems in significantly reducing the size and the function of the articulated manipulator having such a structure. First, as the number of joints increases, many wires are required at the base of the multi-joint manipulator to control them independently. Also, if a sensor is incorporated in each joint to perform feedback control in order to accurately control the displacement of each joint,
The number of wires required for them further increases.

Therefore, an endoscope of the type shown in FIG. 5 has been proposed. The bending portion 20 in the insertion portion of the endoscope is of a type that bends only in two directions,
As shown in FIG. 5A, five joint pieces 21 are connected in series. Adjacent joint pieces 21 are pivotally attached by pins 22. V-shaped notches 23 are provided alternately at the upper and lower sides of the pivotally connected connection portion, so that each joint piece 21 has a hexagonal sectional shape as shown in FIG.

In each V-shaped notch 23, a drive member 2 made of a V-shaped plate-shaped shape memory alloy (SMA).
4 is fitted and it is fixed to the joint piece 21.
The drive member 24 made of this shape memory alloy remembers the folded shape, and when heated, it becomes the folded memory shape. Each drive member 24 is heated by a heater selectively energized by a drive circuit described later.

Each joint piece 21 has five drive circuits D ₁ and D ₁ .
₂ , D ₃ , D ₄ , and D ₅ are provided. Each drive circuit D
₁ , D ₂ , D ₃ ... Are constructed as shown in FIG. The power line 25 from the hand side to the insertion part of the endoscope,
The control signal line 26, the clock line 27, and the GND line 28 are extended. Further, each drive circuit D ₁ , ...
A flip-flop (DFF) 29 is provided, a control signal is input to the data input terminal D, and a clock input terminal C
A clock signal is input to K. The output of the output terminal Q of the D flip-flop 29 is the switching transistor (F
ET) 30 and its output becomes high level, the switching transistor 30 is turned on and the heater 31 for heating the driving member connected between the power supply line 25 and the GND line 28. It is designed to energize.

Next, the bending operation of the bending portion 20 of the endoscope will be described with reference to the time chart of FIG. Here, a clock signal equal to the number of joints is transmitted in every fixed unit time (100 msec) cycle. At this time, the clock signal is transmitted for 1 msec, and the joint to be bent is selected within this time. The remaining 99 msec is spent to hold the movement of the drive member 24 (actuator).

Now, for example, when it is desired to actuate the driving members 24 of the second and third joint portions counted from the hand side to bend the joint portions, five clock signals as shown in FIG. 5C are used. A pulse signal is transmitted at a corresponding time in synchronization with. Then, the first D flip-flop 29
After the input of 5 clock signals, its output Q ₅ goes to L level, and the corresponding switching transistor (FET) 30 remains off, and the first heater side 3
1 is not heated. Therefore, since the drive member 24 of the first joint portion does not operate, the joint portion does not bend.

[0009] The next drive circuit D ₂ of the D flip-flop 2
The output of Q ₅ is input to 9 and the signal similarly shifts to L level after the selection time, and the driving member 24 of the second joint portion does not operate, so that the joint portion does not bend. The D flip-flop 29 in the third and fourth drive circuits D ₃ and D ₄ becomes H level after the selection time, the switch transistor 30 is turned on, and the respective heaters 31 corresponding thereto drive the drive member 24. Is heated to bend the third joint part downward and the fourth joint part upward. By appropriately selecting the pulse of the control signal in this way, it is possible to make an arbitrary joint bend. Therefore, the bending portion 20 can be bent up and down in an arbitrary state as a whole.

During the selected time, the switch transistor (FET) 30 is momentarily turned on and the heater 31 is turned on.
Is energized, but this is not really a problem because of the poor thermal response.

According to this method, since the digital control is possible, the circuit structure is simplified. In particular, it is advantageous to make it into a chip to make it ultra-small. In addition, if you want to make the movement smooth, you can make some smooth motion by shortening the unit time. But,
In the example of this system, only on / off control can be performed with a pulse signal, and it has been difficult to realize smooth movement.

US Pat. No. 3,712,481 proposes that an analog signal is transmitted to a plurality of modules. In this method, the control signal line for transmitting the analog signal is a module. Is required, and it is difficult to reduce the diameter. In this respect, this is a problem in the field of endoscopes in which the diameter reduction is required as much as possible.

The present invention solves such a problem by
An object of the present invention is to provide a small-sized flexible tube device having multiple degrees of freedom, which enables smooth movement by independently controlling a plurality of actuators provided in a plurality of joints with a small amount of wiring.

[0014]

SUMMARY OF THE INVENTION The present invention has a multi-degree-of-freedom structure comprising a plurality of bending operation actuators provided in a flexible tube and a plurality of drive means for driving the actuators. In the flexible tube device, a control signal line for transmitting one analog control signal provided in the flexible tube, one synchronization signal line, and an analog control signal transmitted by the control signal line are selectively used. And a plurality of selecting means for inputting to the driving means. According to this, a plurality of actuators can be independently controlled with a small amount of wiring, and smooth movement is possible.

[0015]

EXAMPLES Examples of the present invention will be described below. A first embodiment is shown in FIG. 1 and FIG. FIG. 1A shows a bending portion 1 formed near the distal end portion of an insertion portion of an endoscope, and the bending portion 1 is formed by connecting n joint pieces 2.
Between the two adjacent joint pieces 2, bending operation actuators A ₁ , A ₂ , A ₃ ... A _n each made of a directional shape memory alloy (SMA) wire 3 that expands and contracts in the axial direction are installed. Has been done. The positions at which the wires 3 are installed are alternately staggered in each joint. Each end of the wire 3 is attached to the corresponding joint piece 2. Furthermore, each joint piece 2
Inside each of the actuators A ₁ , A ₂ , A ₃
A drive circuit 4 for operating A _n is provided.

FIG. 1B shows the actuators A ₁ , A.
₂ , A ₃ ... A _n and the drive circuits D ₁ , D ₂ , D ₃ ... D _n are connected. An actuator A provided between the first joint piece 2 and the second joint piece 2 counted from the tip end side.
₁ is connected to a common GND line 5 which extends from one end to the common GND line ₁ , and the other end is connected to a drive circuit D ₁ . The drive circuit D ₁ includes a power supply line 6 for supplying energy to the actuator A ₁ , a clock signal line 7 and actuators A ₁ , A ₂ , A which are sent at a constant cycle.
₃ ... An control signal line 8 for controlling the operation of A _n . The actuators A _{2 to} A _n are similarly connected. That is, the GND line 5, the power supply line 6, the clock signal line 7, and the control signal line 8 are commonly used.

FIG. 1C shows a concrete structure of the drive circuits D ₁ ... D _n . In particular, the drive circuit D ₁ is composed of only the sample hold circuit 10 ₁ , but the other drive circuits D ₂ ... D _n are the sample hold circuits 10 ₂ to 10 _n and the delay circuits 11 _{2 to} 11 _n. It consists of and. For this reason, the values of the control signal appear in the actuators A _{2 to} A _{n as} they are while the clock signal is L, and when the clock signal is H, the value obtained by holding the value immediately before that appears.

The clock signal transmitted through the clock signal line 7 repeats a pulse having a pulse width t at a constant period T as shown in FIG. In this case, the period T is actuated - is set larger than the product "nt" of data A _1, A ₂ ... A _n number n and the pulse width t of. This plurality of actuator to a single control signal line - in order to send the data - de by time division control information data _{A 1, A 2 ... A n} . Similarly, as shown in FIG. 2, the control signal is an analog signal whose voltage changes at every constant time t, and the respective voltage values V ₁₁ , V ₂₁ ,
Each of the actuators A ₁ , A ₂ ... A described above for V ₃₁ ... V _n1
Control the behavior of _n .

The time-divided signals on one control signal line 8 from the proximal side of the endoscope are sent to drive circuits D ₁ , D ₂ ... D _n provided in the bending section 1. The drive circuit D ₁ samples and holds the control signal when the pulse of the clock signal is H, and holds the voltage value V ₁₁ of the control signal at this time until it is sampled and held by the pulse of the next clock signal. It Then, during the constant period T of the clock signal, the voltage value V ₁₁ is applied to the actuator A _1, and the actuator A ₁ contracts in accordance with the voltage value V ₁₁ to generate the _first voltage.
Th joint bends.

The drive circuit D ₂ connected to the actuator A ₂ comprises a delay circuit 11 ₂ having a delay amount t and a sample hold circuit 10 ₂ , and the input clock signal is delayed by the delay circuit 11 _2. It is delayed by t and input to the sample hold circuit 10 ₂ . Then, the voltage value V ₂₁ of the time-divided control signal is held. And a certain time T
The new voltage value V ₂₂ is held at the next clock signal. The second joint flexes according to this voltage value. In this way, the actuator A _n is also (n
-1) The voltage V _{n1 which} is sampled and held by the clock signal delayed by t time and which is held is the actuator A _n.
Applied to. Then, the actuator A _n bends. Although the control signal in this case has a constant voltage, it may not necessarily be constant and may change. For example, in order to improve the responsiveness, a large voltage may be first applied and then decreased. Then, the time when the clock signal is input depends on the change of this analog signal.
₁ , A ₂ , A ₃ ... _An operate.

According to the above construction, however, the power supply line 6, the clock signal line 7, the control signal line 8 and the GN.
It is possible to independently operate a plurality of actuators A ₁ , A ₂ , A ₃ ... A _n only by a total of four lines of the D line 5. Therefore, it is possible to reduce the diameter of the insertion portion of the endoscope.

FIG. 3 shows a second embodiment. In this embodiment, as shown in FIG. 3A, the bending portion 15 of the endoscope connects the joint pieces 12 so as to be bendable in the four directions of up, down, left and right. That is, between the joint pieces 12, the actuators A ₁ , A ₂ ,
A directional shape-memory alloy wire 3 that expands and contracts in the axial direction, which constitutes A ₃ ... A _n , is provided. These other points are the same as those in the first embodiment described above, and the description of their specific configurations will be omitted.

In particular, the actuator (SMA) A ₁ , A
₂ , A ₃ ... And drive circuits D ₁ , D ₂ ... And drive circuit D ₁ ,
The configuration of D ₂ ... Is as shown in FIG.
That is, the drive circuit D ₁ is the sample hold circuit 10 ₁
The other drive circuits D ₂ ... D _n are composed of only sample hold circuits 10 ₂ to 10 _n and delay circuits 11 ₂ to.
11 _n . Then, the sample-hold circuits 10 ₁ , 10 ₂ to 10 _n sample-hold the control signal transmitted from the near side of the endoscope.

A clock signal determines the timing of this sampling, and this clock signal is directly input to the sample hold circuit 10 ₁ and the delay circuit 11 ₂
Through 11 _n to other sample and hold circuits 10 ₂ to 1
Input to 0 _n . Sample-hold circuit 10 ₁ , 10
_The analog signal sampled at ₂ to 10 _n is
It is input to the PWM generation circuits 16 ₁ , 16 _{2 to} 16 _n , which outputs a signal having a pulse width corresponding to the voltage value of the analog signal. Here, the delay amount t of each of the delay circuits 11 _{2 to} 11 _n is set to be constant.

Further, each actuator A ₁ , A ₂ , A ₃
A _n are connected between the GND line 5 and the power supply line 6 via the switching elements SW ₁ ... SW _n1 , respectively. That is, each actuator A ₁ , A ₂ ,
Each switching element SW ₁ ... SW is provided for A ₃ ... A _n .
It is energized through _n1 . Each of the switching elements SW ₁ ...
Is composed of, for example, a power FET or a transistor, and as will be described later, actuators A ₁ , A ₂ , A ₃ ...
Control the power supplied to A _n .

Next, the operation of this embodiment will be described. In each of the drive circuits D ₁ , D _2, ... As in the first embodiment described above, the reference clock signal is delayed and the time-division signal transmitted on one control signal line 8 is sampled. e - and field, actuator - drives the motor _{a 1, a 2 ... a n} . That is, the clock signal is input at regular time intervals (T), the value of the control signal (analog signal) is sampled accordingly, and the value is held for T (a _{1 to} a ₃ ). Then, this signal is the PWM generation circuit 1
6 ₁ , 16 _{2 to} 16 _n , and an analog signal (a ₁
~ A ₃ ) corresponding to PWM generating circuits 16 ₁ , 16 ₂ ~ 1
_6n output pulse width is set and switching element SW
₁ ... to operate the actuators A ₁ , A ₂ , A ₃ ... A _n
It is possible to continuously control the amount of electricity supplied to the.

In this embodiment, the analog signals sampled and held are once converted into PWM circuits 16 ₁ , 16 _{2 to} 16 _n.
It is characterized in that it is converted into digital and is driven by pulse. Thus, according to this configuration, the delay circuit 11
_The amount of delay due to _{2 to} 11 _n is constant at “t”, which enables miniaturization and reduction in the diameter of the endoscope. Further, the pulse drive of the actuator (SMA) improves the response as compared with the analog drive.

Although shape memory alloy (SMA) is used as the actuator in each of the above-described embodiments, a chemo-mechanical actuator and a hydrogen storage alloy actuator are used.
As long as it is a small actuator such as a piezoelectric actuator or a piezoelectric actuator, it is not particularly limited thereto. Further, although the endoscope is shown, it may be a flexible tube such as a catheter, a guide wire, and a manipulator. Further, in the embodiment of the present invention, only one control signal line and one synchronization signal line are used. However, if a large number of bending operation actuators are required, a plurality of bending signal actuators may be provided. The substantial effect of the invention can be obtained.

[0029]

As described above, according to the present invention, even in a flexible tube device having multiple degrees of freedom, a plurality of actuators can be independently controlled by, for example, only four signal lines. The diameter can be reduced.

[Brief description of drawings]

1A is an explanatory view schematically showing the vicinity of a distal end portion of an insertion portion of an endoscope according to a first embodiment, FIG. 1B is an explanatory view of an actuator and a drive circuit thereof, and FIG. ) Is a circuit diagram showing a specific configuration of a drive circuit.

FIG. 2 is a waveform chart showing the operation of the circuit of the first embodiment.

3A is an explanatory view schematically showing the vicinity of a distal end portion of an insertion portion of an endoscope according to a second embodiment, and FIG. 3B is an explanatory view of an actuator and a drive circuit thereof.

FIG. 4 is a waveform diagram showing the operation of the circuit of the second embodiment.

FIG. 5 (a) is an explanatory view schematically showing the vicinity of a distal end portion of an insertion portion of a previously proposed endoscope, FIG. 5 (b) is an explanatory view of an actuator and a drive circuit thereof, and FIG. FIG. 6 is a waveform chart showing the operation of the circuit of the embodiment.

[Explanation of symbols]

1 ... curved portion, 2 ... joint piece, A ₁ to A _n ... for bending operation actuator - data, D ₁ to D _n ... driving circuit, 4 ... driving circuit, 5
... GND lines, 6 ... power lines, 7 ... clock signal line (sync signal line), 8 ... control signal line (control signal line) 11 ₂ to 11 _n ... delay circuit, 10 ₁ to 10 _n ... Sample E - field circuit.

Claims (1)

[Claims] 1. A multi-degree-of-freedom flexible tube device comprising a plurality of bending operation actuators provided in the flexible tube and a plurality of drive means for driving the actuators, respectively. A control signal line for transmitting one analog control signal and one synchronization signal line, and a plurality of selecting means for selectively inputting the analog control signal transmitted by the control signal line to the driving means. And a flexible tube device having multiple degrees of freedom.