JP2017078506A - Linear actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a linear actuator which is improved in drive power, driving speed, environmental resistance, light weight, flexibility, low drive sound and the like.SOLUTION: Within a bag 1, a material 2 which is thermally expanded by absorbing a specific light is encapsulated. Light emitted from a light source 4 that is disposed outside of the bag is introduced through a light guide 3 into the bag 1 and the material 2 is irradiated with the light. Thus, the bag 1 is expanded, and the bag 1 is degenerated in a length direction and converted into drive power of the linear actuator. The light source 4 is a laser beam representatively and the light guide is an optical fiber representatively. As the material 2, a mixture of a host absorbing light and a matrix having a large thermal expansion coefficient and an U-shaped bimetal or a mixture of a catalyst and a solvent and the like are effective. The light guide 3 may also be functioned as a signal transmission line of various sensors required for driving the linear actuator.SELECTED DRAWING: Figure 2

Description

The present invention relates to a linear actuator that can obtain a desired driving force by changing the volume of a substance filled in a container having high flexibility.

As the use of robots and robot suits for self-supporting movements advances, there is an increasing need to drive them with natural movements that are close to human movements.
As a driving method of various robots, a method has been devised in which a desired operation such as grasping, walking, moving an object, etc. is executed by combining with a cam based on the rotational motion of the motor described in Document 1 as a basic operation.

On the other hand, development of artificial muscles and linear actuators that can be driven closer to human movements is underway. As the artificial muscle, McKibben type artificial muscles (RAMs), which used compressed air devised in the 1960s to obtain a tensile force by inflating a bag made of nylon fiber, have been put into practical use. Since then, methods such as piezoelectric elements, electrostatic elements, and bimetal have been researched and developed. Recently, development of a method using a polymer such as an electric field responsive polymer (EAP) and an ion conductive polymer gel (ICPA) has progressed, and development of a linear actuator having a bucky gel type structure has been advanced. . In addition, it has been reported that a nylon thread can be brought close together, cooled and heated to obtain 100 times the strength of human muscles.

JP2009-17711 JP-A-2005-58351 Patent 5666944 JP 2010-279589 JP2001-232600

Japan Society of Mechanical Engineers [No. 00-2] Robotics and Mechatronics Lecture 2P1-47-079

As the linear actuator, a system in which an electromagnetic drive motor and a gear are combined is widely used. A linear actuator using an electromagnetic drive motor as a driving source has excellent features such as reliability, driving force, low cost, and rotation controllability, but also has problems.
The drive system using a rotary motor has excellent features such as reliability, versatility, low cost, and rotation controllability, while mechanical drive converters such as gears and cams are used for operations other than rotation. There was a problem that it was necessary and flexible operation was difficult.

On the other hand, for an artificial muscle, a method using the linear motor of Document 2 has been proposed. However, since the electromagnetic field force is used, the volume and weight of the magnet and the coil increase, and at the same time, electrical noise is accompanied. In addition, there is a problem that there is a limit to environmental resistance such as dust, sand dust, submergence resistance, corrosive gas, vibration shock, and radiation of the mechanical drive unit.

On the other hand, the method of sending compressed air to the bellows-like cylindrical body of Document 3 to expand and contract, the method of improving PAMs using compressed air of Document 4, and the like are disclosed. These methods can be operated with excellent flexibility similar to human movements, and although there is a merit that the artificial muscle alone has a small weight, a compressor for generating compressed air is required, and compressed air control For this reason, there is a problem that the size, weight and noise of the entire apparatus increase due to the necessity of a solenoid valve.

On the other hand, Document 5 discloses a method in which a laser beam is used as a drive source and a bending operation is performed using a phase transition of a substance irradiated with laser. If this method is used, it is possible to minimize the drive sound and to reduce the weight and size of the entire apparatus. However, the bending movement of the phase transition has problems such as not being able to obtain a sufficient driving force and driving amount as a linear actuator, causing bending movement due to the influence of external light, and low mechanical toughness. .

On the other hand, Non-Patent Document 1 discloses a method of bending operation while securing mechanical toughness by irradiating a laser beam leaked from an optical fiber onto a shape memory alloy pipe disposed so as to surround an optical fire. It is disclosed. Even in this method, sufficient driving force and driving amount as a linear actuator cannot be achieved, and there are problems such as limitation of the driving temperature range depending on the material of the shape memory alloy.

An object of the present invention is to solve these problems, and to provide a linear actuator that is light and low in noise and further excellent in environmental resistance while securing a particularly flexible and high driving force.

In order to solve the above problems, a linear actuator according to the present invention encloses a material whose volume is changed by an external element inside a bag, and serves to change the volume of the material from the outside of the bag. It is characterized by consisting of supplying. Here, the “linear actuator” referred to in the present specification includes a structure that is highly flexible and obtains a driving force by controlling the amount of expansion and contraction like a muscle of a living body. In addition, the “bag” includes a container having a high degree of freedom in shape, which has a poor elasticity but can change its volume.

According to this configuration, a mechanism for supplying and discharging a gas necessary for driving from the outside is not required unlike PAMs and steam engines, or a mechanism for igniting a material such as fuel after spray supply as in an internal combustion engine Therefore, it is possible to obtain a linear actuator that can perform repeated operations in a self-contained manner.

Furthermore, the driving force of the linear actuator according to the present invention mainly depends on the strength of the bag and the Young's modulus of the material used for the volume change inside the bag and / or its volume, and the driving speed of the linear actuator according to the present invention is as follows: Since it mainly depends on the expansion / contraction speed of the material and / or the amount of light energy supplied per unit time, it is possible to achieve both high driving force and driving speed by selecting an appropriate material and structure.

As a light energy source for providing a volume change of the material enclosed in the bag, laser light supplied via an optical light guide or a light guide line is typical. Typical examples of the material enclosed in the bag include resin, metal workpiece, liquid, and a mixture of liquid and gas.
A catalyst can also be used to promote the volume expansion of the material inside the bag by the introduced light energy source. Further, for the purpose of promoting the volume reduction of the bag, it is also possible to arrange a cooling pipe, a medium, etc. inside the bag and / or outside the bag.

By using the above means, in the state where the end portion of the bag is held and stress is applied, the linear actuator according to the present invention is driven in the pulling direction due to the volume expansion of the bag, and the bag is The linear actuator according to the present invention is reversibly driven in the extending direction by volume reduction. The bag is typically a braided lace made of carbon fiber, a metal foil, a resin foil, and a laminate thereof.

Furthermore, along the guide provided on the structure having one or more joints holding the bag at the end or / and the middle of the bag, and having a tendon connected to the bag The tendon slides. As used herein, the term “tendon” refers to a string-like portion made of a continuous structure with the bag, and is preferably made of the same material as that of the bag, but is composed of a material different from that of the bag. It is also possible to use.

The configuration of the present plan includes a light source that emits a wavelength in a specific region that provides good light absorption characteristics with respect to the material inside the bag, and a light guide means that introduces the emitted light into the bag. . Furthermore, means for cooling the material inside the bag from the outside of the bag is included. The light guide means is typically an optical fiber. Various sensor signals used for operation control of the linear actuator according to the present invention and various optical signals and energy light other than the linear actuator according to the present invention can be multiplexed on the optical fiber. Typical examples of the multiplexing method include wavelength division multiplexing, polarization division multiplexing, time division multiplexing, and code division multiplexing.

Further, the material filled in the bag is a flexible material having a high degree of freedom in shape, and by using means for connecting a plurality of the bags, the flexibility of the linear actuator according to the present invention can be ensured, and the Since a sufficient driving amount can be obtained as a whole while suppressing individual volume expansion of the bag, it is possible to arrange the same as the muscles constituting the living body.

One driving means of the present invention includes means comprising a host material as the energy light absorber and a matrix as the thermal expansion body. The host material is dispersed in the matrix material. The energy light is absorbed by the host material and its temperature rises rapidly. The amount of heat generated at this time is conducted to the matrix material, and the matrix material is effectively heated to cause volume expansion, which is converted into the driving force of the linear actuator according to the present invention.

In addition, by using this means, the host material having a high light energy absorption rate and the matrix material having a high coefficient of thermal expansion can be separated and arranged, so that the degree of freedom in selecting the material is improved and driving is performed. Efficiency can be increased. It is preferable that the host material dispersed in the matrix material is selectively arranged in the dispersion density according to the intensity distribution state of the energy light.

As one driving means of the present invention, there is included means for enclosing the inside of the bag together with a solvent and a catalyst for promoting a photochemical reaction of the solvent. The energy light introduced into the bag causes a chemical reaction of the solvent through the catalyst, causes decomposition and vaporization reaction, enlarges the volume of the bag, and increases the driving force of the linear actuator according to the present invention. Converted. For the gas decomposed and vaporized by the above means, only the generated gas can be discharged out of the bag by using a mesh capable of separating the gas and liquid in the bag.

As one driving means of the present invention, a means for disposing a second catalyst or / and medium made of a material different from the catalyst in the bag and / or a wavelength different from the wavelength used for the photochemical reaction is used. Means for introducing into the bag are included. Thereby, the gas decomposed and generated from the solvent by the above means can be condensed or / and liquefied. By using this means, it is possible to reduce the volume of the bag that has been volume-expanded, and the bag can be expanded and contracted reversibly.

As one driving means of the present invention, a first material that expands by absorbing energy light introduced into the bag and rising in temperature, and a first material that is in close contact with and integrated with the first material, Means are included for inserting one or more bent pairs of second material having a smaller expansion coefficient than the material into the bag. By using this means, the bending pair heated by the energy light is deformed, and the volume of the bag is enlarged, so that the driving force of the linear actuator according to the present invention is converted.

As one driving means of the present invention, the light beam or light guide includes a plurality of light branching means, and each of the branched light beams or light guide and the linear actuator according to the present invention are optically connected. It is connected. Furthermore, the light source light has means for outputting a plurality of wavelengths, and the linear actuators according to the present invention arranged to correspond to the respective wavelength lights can be driven independently or simultaneously.

One drive control means of the present invention includes means for converting a sensor signal into an optical signal and means for using the light beam or light guide to transmit a signal from the sensor to the drive control processor. The driving energy of the sensor includes means for transmitting as light energy through the light beam or light guide and means for converting it into an electrical signal in the vicinity of the sensor. Accordingly, a plurality of linear actuator driving energies according to the present invention, driving energies of a plurality of sensors, and information signals can be multiplexed and transmitted by one light beam or light guide. As the multiplexing method, means such as wavelength multiplexing, polarization multiplexing, and time division multiplexing are used.

As one drive control means of the present invention, an optical sensor is used as a sensor, and a light source supply to the optical sensor and sensor optical signal information using the optical beam or the optical light guide are included. When handling a plurality of photosensors, it is possible to handle a plurality of photosensors independently by using various multiplexing means such as wavelength multiplexing, polarization multiplexing, and time division multiplexing.

As one driving means of the present invention, a plurality of light branching means to the light beam or light guide, and a means for connecting the light beam or light guide after branching to the linear actuator and photoelectric converter, including.

Accordingly, a plurality of linear actuators according to the present invention and a plurality of electric actuators can be used in parallel by one light beam or light guide. The drive control of each linear actuator according to the present invention can be handled independently by means such as wavelength multiplexing, polarization multiplexing, and time division multiplexing.

  According to the present invention, a material stored in a bag constituting a linear actuator rich in bending flexibility is driven by being expanded and contracted by supplying energy from the outside of the bag, thereby driving with high accuracy and large drive. It is possible to provide a linear actuator that can obtain force, has a high degree of freedom in arrangement, is small, lightweight, has low noise, and is excellent in environmental resistance.

Furthermore, by using a light beam or a light guide as an external energy supply path, the drive energy of the linear actuator and the optical signal related to the control of the linear actuator can be multiplexed and transmitted. Collective control is possible with a light guide line and a light guide. This contributes to the reduction in size and weight of the humanoid robot system using the linear actuator according to the present invention, and also enables the drive energy source and the control system to be separated from the humanoid robot, thereby enabling humans in extreme environments. This also has the effect of facilitating the work of the robot.

It is a figure explaining the operation principle of the linear actuator by this invention. It is a figure explaining the operation principle of the linear actuator by this invention using light. It is a figure explaining the structural example of the linear actuator by this invention using light. It is a figure explaining the principle of operation of the linear actuator by the present invention using vaporization expansion of a solvent. It is a figure explaining the structural example of the linear actuator by this invention using an expansion coefficient difference. It is a figure explaining the principle of operation of the linear actuator by the present invention using the expansion coefficient difference. It is a figure explaining the operation principle of the linear actuator by this invention using the expansion coefficient difference which has the shape wound by the coil shape. It is a figure explaining the operating principle of the linear actuator by this invention which has a some bag. It is a figure explaining the calculation method of the expansion rate of a bag, and the linear actuator drive amount by this invention. It is a figure which shows the expansion rate of a bag, and the linear actuator drive amount calculation result example by this invention. It is a block diagram which shows the control structural example of the linear actuator by this invention. It is a figure explaining the example which used the linear actuator by this invention for the inclination drive of a joint. It is a figure explaining the example which applied the linear actuator by this invention to the rotational drive of a joint. It is a figure explaining the linear actuator drive amount and inclination angle calculation method by this invention at the time of using for the inclination drive of a joint. It is a figure which shows the result of having calculated the relationship between the linear actuator drive amount by this invention, and a joint inclination angle. It is a figure explaining the example which drives a joint using the linear actuator by this invention of this invention of the structure which connected the some bag. It is a figure explaining the example which drives a some joint using the linear actuator by this invention. It is a figure explaining the example which used the linear actuator by this invention as a drive module equivalent to the arm of a humanoid robot. It is a figure explaining the example of arrangement of a light guide line and various sensors at the time of applying to a module equivalent to an arm of a humanoid robot using a linear actuator by the present invention. In the module corresponding to the arm of the humanoid robot using the linear actuator according to the present invention, a configuration example for cooling the linear actuator according to the present invention by enclosing the module in a bag and filling the bag with liquid. is there. It is a figure explaining the example which used the linear actuator by this invention as a drive module equivalent to the leg of a humanoid robot.

Embodiments according to the present invention will be described below.
This description is intended to confirm the contents of the present invention by using specific examples, and is described in the details of the invention. Even if there is an embodiment which is not described here as a form, it does not mean that the embodiment does not correspond to the constituent requirements. Further, this does not mean that the described embodiment does not correspond to configuration requirements other than the configuration requirements.

FIG. 1 shows the driving principle of one aspect of a linear actuator according to the present invention.
A material 2 is enclosed in a bag 1 made of a material that is poor in elasticity but rich in flexibility. When the bag 1 is filled with the material 2 up to an allowable volume, it becomes a sphere. On the other hand, when the filling rate of the container is smaller than that at the time of forming the sphere, the container is deformed into an ellipsoid. For example, when a constant tensile stress F is applied to both ends of the container in a state where the filling rate is smaller than 50% as shown in FIG. 1A, the container is deformed, and the total length is L1 according to the filling amount inside the container. It transforms into an elliptical shape. When the material 2 inside the container expands from this state, the cross-sectional area of the ellipsoid increases according to the volume expansion coefficient.

Since the surface area of the container 1 which is poor in elasticity but rich in shape flexibility is constant, as shown in FIG. Degenerate to L2. This degeneration of the container 1 becomes the driving force of the linear actuator.

FIG. 2 shows the principle of driving a linear actuator by using a light source 4 as a driving energy source of a linear actuator according to the present invention and introducing energy light into the bag 1 through a light guide wire 3 to thermally expand the material 2. Show. As an example of the light guide line 3, an optical fiber is preferable. Typical materials for optical fibers are glass and plastic, but hollow tubes can also be used.

The light emitted from the light source 4 is guided to the bag 1 by using the light guide line 3 and irradiated to the material 2. (FIG. 2 (a)). The light source 4 is typically a module composed of a sealed container in which a chip that emits laser light is stored, and a light guide wire 3 optically coupled via a lens. A plurality of chips emitting laser light can be arranged in parallel to increase the output, or a plurality of laser light emitting chips having different wavelengths can be used. In addition, other light sources such as an LED light source and a xenon light source can be used.

The light guide wire 3 passes through the bag 1 and is guided to the material 2 stored in the bag 1. The light source light emitted from the end portion of the light guide line 3 is efficiently applied to the material 2 through a lens or the like. The material 2 has a composition that efficiently absorbs the introduced light, and the temperature of the material 2 rises according to the intensity of the irradiated light, causing body expansion (FIG. 2B). As a result, the cross-sectional area of the bag 1 is expanded, so that the entire length in the longitudinal direction of the bag 1 is reduced and the linear actuator is driven.

FIG. 3 shows a configuration of one side surface inside the bag 1 in a system in which the linear actuator is driven using volume expansion due to light energy of the material 2 according to the present invention. The inside of the bag 1 is hollow, both ends are closed with the material of the bag 1, and the extension portion has a feature including a bush 8 for fixing the linear actuator. The bag 1 has a low stretchability but a high tensile strength, a light weight, and a configuration in which carbon fibers excellent in heat conductivity are knitted.

As shown in FIG. 3A, the material 2 has a high coefficient of thermal expansion and is suitable for a composition and configuration that can ensure the flexibility of the bag 1, and is enclosed so as not to leak out of the bag 1. ing. The material 2 is preferably a polyethylene terephthalate fibrous sponge, a colloidal polyethylene terephthalate microsphere-solvent mixture, a stabilizing gel, or the like.

In the material 2, a light absorber 5 having high absorption characteristics is dispersed with respect to light introduced and irradiated into the bag 1. The light guide wire 3 is inserted in a coiled state so as to penetrate the inside of the bag 1. By winding the light guide wire 3 in a coil shape, light leaks from the coiled portion and diffuses to the surroundings according to the winding diameter, the diameter of the light guide path, the wavelength of the light source 4 and the like. The diffused light source light is absorbed by the light absorber 5 and converted from light to heat.

The light absorber 5 is preferably a metal chelate complex of ethylenediamine, bipyridine, ethylenediamine complex, phenanthroline, and a metal chelate complex of polyphylline and crown ether, each composed of a cyclic ligand. When, for example, benzopyromethene is used as the metal chelate complex, a laser beam having an emission wavelength band from 540 nm to 620 nm is suitable.

FIG. 3A shows a state in which the cooling pipe 6 is disposed so as to pass through the central portion of the light guide wire 3 wound in a coil shape. The cooling medium in the cooling pipe 6 circulates in the cooling pipe using the expansion / contraction drive of the linear actuator. By arranging the heat exchanger in the middle of the cooling pipe 6, the cooling effect is enhanced. Use of a shape memory alloy as the material constituting the cooling pipe 6 is preferable because thermal conductivity as cooling can be secured and the overall length of the cooling pipe 6 can be controlled in conjunction with the expansion and contraction operation of the bag 1.

With the above configuration, light introduced into the light guide wire 3 causes a light guide loss at the coiled portion and leaks into the bag 1. The leaked light is efficiently absorbed by the light absorber 5 and converted into heat. The heat generated in the light absorber 5 is conducted to the material 2 excellent in thermal expansion and expands. As a result, the cross-sectional area of the bag 1 is enlarged, and the near actuator is driven to degenerate as the entire length of the bag 1 is degenerated.

FIG. 3B shows an example in which the inside of the bag 1 can be cooled more efficiently by winding the cooling pipe 6 in a coil shape, and at the same time, the change in the total length corresponding to the expansion and contraction operation of the bag 1 can be handled. At the end of the bag 1, the cavity is terminated, and the material of the bag is extended to be processed into a string shape. The light guide line 3 and the cooling pipe 6 are arranged so as to be inserted into the string-like part. Further, a bush 8 for mechanically locking the linear actuator to the structure is attached to the end portion of the string-like portion.

FIG. 3C illustrates a configuration in which the light derived from the light guide wire 3 is irradiated to a specific part of the bag 1 by the illumination module 7.
The illumination module 7 is formed into an arbitrary light beam shape by using a diffraction grating, a microlens array, or the like, and is irradiated into the container. Thereby, it becomes possible to collect the irradiation range of light source light into arbitrary ranges, and the utilization efficiency of light source light increases.

When the divergent light from the illumination module 7 takes the form of a Gaussian distribution starting from the light emitting point, the distribution density of the light absorber 5 is set so as to be inversely proportional to the intensity of the irradiation light. Uniform heating is preferable. When the light supply from the light source 4 is stopped, the expansion of the container 1 is stopped, the material 2 is cooled by the cooling pipe 6 introduced into the container, the degeneration of the linear actuator is stopped, and it is driven in the extending direction. The light energy can also be effectively utilized by leading the light guide wire 3 and the cooling pipe 6 out of the container from one end of the container and introducing it again into the next container.

FIG. 4 shows a configuration example of another aspect of the linear actuator according to the present invention. By enclosing the solvent 10 in the bag 1 having airtightness, and condensing and radiating the light toward the catalyst 9 from the illumination module 7 optically coupled to the light guide 3 inserted in the bag 1, A photochemical reaction region 11 is formed around the catalyst 9.

In the photochemical reaction region 11, the solvent 10 is decomposed and vaporized, and the volume of the bag 1 rapidly expands and is converted into the driving force of the linear actuator. Although the vaporized solvent 10 is not illustrated, it is cooled by a cooling pipe provided inside the bag 1 to cause a coagulation reaction and return to the solvent again, thereby stopping the degeneration of the linear actuator. The bag 1 is driven by the external force F in the extending direction.

The decomposed gas can be discharged to the outside of the bag 1 through a fine gap in the mesh constituting the bag 1. By optimizing the mesh gap, only the gas can be discharged while the solvent 10 is sealed in the bag 1. It is also possible to store the gas discharged from the bag 1 in an exhaust collecting container, cool it down, return it to the solvent 10 state, and then supply it again into the bag 1 for reuse.

As the solvent 10, a diluted solution of ethylene glycol and higher alcohol is suitable. In the case where an alcohol-based diluent is used as the solvent 10 as the catalyst 9, a nickel-alumina porous body is suitable. In addition, the flexibility of the bag 1 is maintained and suitable by using a noble metal sponge body processed into a line as the catalyst 9.

FIG. 5 shows a configuration example of another aspect of the linear actuator according to the present invention. By absorbing the energy light emitted from the light source 4 through the light guide line 3 and the illumination module 7, it is arranged so as to be in close contact with the joined body 14 (a) that rises in temperature and expands, and the joined body 14 (a). And the feature which uses the U-shaped processed body which has the some arm which consists of the joined body 14 (b) whose expansion coefficient is smaller than the joined body 14 (a) as the raw material 2 for the volume expansion of the bag 1 is used. Have.

FIG. 5A shows one aspect of a drive principle having a configuration in which a U-shaped workpiece having four arms is fixed so as to connect the bushes 8 provided at both ends of the bag 1 by wires 13. Show. The wire 13 is locked to each of the four arms, and one of the four wires 13 is formed at the base portion of the U-shaped workpiece and the extension of the wire 13 having a length approximately equal to the length of the arm. It is bundled with the wire.

The energy light emitted from the illumination module 7 is absorbed by the joined body 14 (a) and heats and expands the joined body 14 (a). On the other hand, the joined body 14 (b) is shielded from light by the joined body 14 (a) and has a configuration in which the temperature hardly rises, and the expansion coefficient is smaller than that of the joined body 14 (a). As illustrated in FIG. 5B, the bonded body 14 processed into a U shape is deformed in the opening direction.

Due to the deformation of the joined body 14, the area of the region surrounded by the tip portions of the four arms is enlarged. The bonded body 14 is typically a bimetal, but may be a bonded body made of non-ferrous metal having a different composition. Note that by increasing the number of arms of the U-shaped workpiece, the driving force as the linear actuator and the rigidity of the U-shaped workpiece can be increased. Further, by setting the number of arms to two, it can be used as a thin linear actuator having a large cross-sectional aspect ratio.

In addition, since the joints between the U-shaped workpieces have a degree of freedom of movement in the bending and rotation directions, it is possible to drive the linear actuator to follow the structure having a three-dimensional aspect. . As an application example of the thin linear actuator described above, for example, to a part corresponding to the genital muscle, the muzzle muscle, the lower-angular control muscle, the lower lip control muscle, the ocular muscle, the frontal muscle, etc. in the facial muscle of a humanoid robot Can be exemplified.

FIG. 6 illustrates a configuration in which seven joined bodies 14 processed into a U shape are connected and sealed in the bag 1. The connecting portions of the joined bodies 14 are joined by wires 13, and have flexibility in driving in the bending direction and the rotating direction between the joined bodies 14, and the flexibility of the bag 1 is ensured.

The illumination module 7 is arranged so as to face each joined body 14, and as shown in FIG. 6A, energy is supplied to each illumination module 7 from the light guide line 3 using the multiplexing / demultiplexing / branching device 15. The light is distributed. When the joined body 14 is irradiated with energy light and the joined body 14 processed into a U-shape is deformed in the opening direction, the cross-sectional area of the bag 1 is enlarged, and the distance between the bushes 8 is degenerated and converted into driving force. The

In addition, in the wiring of the illumination module 7 and the light guide line 3 arranged so as to face each joined body 14, it is possible to connect the light source 4 directly without using the multiplexing / demultiplexing / branching unit 15. Each joined body 14 processed into a shape can be driven independently. Thereby, for example, it is possible to cope with a complicated movement in which the inside of the pipe is moved by the peristaltic movement of the bag 1.

FIG. 7 shows the winding diameter of the spiral bonded body 14 by disposing the light guide wire 3 inside the spirally bonded body 14 and heating the bonded body 14 with the energy light leaked from the light guide line 3. Is enlarged, and the cross-sectional area of the bag 1 is enlarged to convert it into driving of a linear actuator. The joined body 14 (a) having a larger thermal expansion coefficient is arranged inside the helix, and the light guide wire 3 is arranged so as to contact along the joined body 14 (a) (FIG. 7 (a)). The spiral joined body 14 is enclosed in the bag 1 and the bush 8 is attached to both ends.

When the energy light is guided to the light guide line 3, the energy light leaks from the light guide line 3, and the joined body 14 (a) is absorbed and heated. Since the joined body 14 (a) has a larger amount of thermal expansion than the joined body 14 (b), the joined body 14 (a) is deformed in a direction in which the spiral diameter is increased. As the diameter of the spiral bonded body 14 increases, the cross-sectional area of the bag 1 increases, and a driving force acts in a direction to shorten the distance between the bushes 8. In addition, when the amount of energy light leakage from the light guide line 3 is not sufficiently obtained, the tapered light guide line 3 is formed by gradually reducing the light guide path diameter of the light guide line 3 in the direction in which the energy light is guided. Is preferred.
In addition, by arranging the light guide wire 3 at a different part of the spiral joined body 14 as a set independently of the light source 4, the spiral diameter of an arbitrary portion of the spiral joined body 14 can be selectively enlarged. .

FIG. 8 illustrates the configuration of a linear actuator that uses energy light having a configuration in which five bags 1 are arranged in series as a drive source. Each bag 1 having an independent energy supply path is driven by a structure that can irradiate each material 2 via five light guide lines 3 bundled corresponding to each bag. Depending on conditions, the amount of expansion is controlled, and an arbitrary driving force and driving speed can be obtained.

For example, when only the containers No. 2 and No. 4 are expanded (FIG. 8B), the total length of the linear actuator is changed from L1 to L2. When all the containers No. 1 to No. 5 are expanded (FIG. 8C), the total length of the linear actuator is reduced to the minimum length L3. Moreover, it is also possible to control each bag 1 independently by arranging different wavelengths to be absorbed by each material 2 and multiplexing five wavelengths respectively corresponding to one light guide line 3.

As described above, more accurate drive control is possible, and the maximum cross-sectional area of the bag 1 with respect to the unit drive amount of the linear actuator can be set small. Further, a larger driving force can be obtained by bundling linear actuators having a plurality of containers arranged in series in parallel.

FIG. 9 is a diagram for explaining the specifications of the mathematical formula used when calculating the relationship between the body expansion rate of the container constituting the linear actuator and the drive amount. As shown in FIG. 9A, when the coating of the container is an inelastic body, it becomes a sphere when the inside of the container expands to the limit volume of the container. When the radius at this time is Re, the volume Ve and the surface area Se of the sphere are expressed by Equation 1.

Here, as shown in FIG. 9B, when the volume inside the container is reduced in a state where tensile stress F is applied to both end faces of the sphere, the sphere increases the load direction of the stress F according to the volume reduction amount. It becomes an ellipsoid with an axis. If the major axis radius at this time is R ₁ and the minor axis radius is R ₂ , the volume is expressed by Equation 2. However, it is assumed that there is no elastic contraction due to the tensile stress F.

In this case, the surface area of an ellipsoid becomes S _e is the same as the sphere. As the volume fraction of the container alpha, the relationship between the surface area S _e and R _1, R ₂ of the ellipsoid is expressed by Equation 3. In the case of a sphere, α = 1.

乗数ｐはｐ＝１．６０７５とした場合、誤差率を１．０６１％に抑えられることが知られている。
そこで、体積減少に伴う楕円体の長軸変動の理論計算では、数式４を用いた。
ここで、Ｒ_１＞Ｒ_ｅ＞Ｒ_２，Ｖｍ＜Ｖｅ，とする。On the other hand, the surface area of the ellipsoid can be approximated by Equation 4 using the multiplier p.

It is known that when the multiplier p is p = 1.6075, the error rate can be suppressed to 1.061%.
Therefore, Formula 4 was used in the theoretical calculation of the long axis fluctuation of the ellipsoid accompanying the volume reduction.
Here, it is assumed that R ₁ > R _e > R ₂ and Vm <Ve.

On the other hand, since R ₂ is affected by the volume of the container, the mechanical properties of the skin, gravity and the like, strictly speaking, it cannot be an ellipsoid. However, in order to simplify the calculation, the calculation was performed assuming that the relationship of R ₂ = R ₁ ⁿ holds. A numerical value by which the calculation result of the area of the ellipsoid and the volume of the ellipsoid (Vm) when R ₁ and n are set to arbitrary numerical values is infinitely consistent with the initial values of the spheres was obtained by Equation 5.

When the volume of the container forming the linear actuator is small as in the case of α = 0.1, if the relationship between α and R ₁ of the ellipsoidal short axis is adopted, the area and volume errors with respect to the initial value of the sphere do not converge. It was.
For this reason, it is calculated as an individual optimum numerical value not related to R ₁ . When α is 0.2 or more, error convergence is good and a constant correlation is obtained between α, R ₁ and n.

FIG. 10 shows the relationship between α and R ₁ when Re = 10 mm. The initial volume of the vessel was 25% of the sphere S _e, substantially the same total length of the linear actuator when it is assumed from the initial volume and was 20% volume expansion, when the α and R ₁ is assumed to be power approximation, the volume expansion rate It is expected to shrink about 19.7%.

The driving force of the linear actuator originates from the thermal expansion stress of the material inside the container. Incidentally, the Young's modulus of the vessel Ea, volume expansion ratio A, the amount of temperature change [Delta] T, when the volume of the container and V _he optical actuator driving force sigma _he is represented by Equation 6. κ indicates the thermal expansion stress conversion efficiency of the material in the container

FIG. 11 shows a connection path of the light source 4 supplied to the linear actuator, signal circuits of various sensors 22 and optical sensors 17 used for controlling the driving of the linear actuator, and a control processor 20 for integrally controlling them. The block diagram explaining the example of a connection is illustrated.

In addition to the supply of energy light to the linear actuator in the present invention, the communication between the optical sensor 17 and various sensors 22 used for control and the control processor 20 is multiplexed as an optical signal on the light guide 3. Typical optical multiplexing methods include optical communication techniques such as wavelength multiplexing, polarization multiplexing, deflection multiplexing, time division multiplexing, and optical code division multiplexing.

Note that communication other than the optical sensor, such as the sensor 22, is performed after being converted from an electrical signal to an optical signal by the photoelectric converter 21 and then multiplexed on the light guide line 3. As a result, the energy light for driving the linear actuator in the present invention and the optical signal provided from the photoelectric converters 21 connected to the plurality of optical sensors 17 and the plurality of sensors 22 are multiplexed onto one light guide line 3 and controlled. The processor 20 can be connected and controlled.

On the other hand, the linear actuator driving light source 4 in the present invention connected to the control processor 20 is introduced into the light guide line 3 through the multiplexing / demultiplexing filter 16. Similarly, an optical signal generated from the plurality of optical sensors and the photoelectric converter 21 connected to the plurality of sensors 22 also passes through the multiplexing / demultiplexing filter 16 to the optical signal transmission light source 4 or the light receiving module 19 on the control processor 20 side. And is used for control of the linear actuator in the present invention.

The sensor 22 is typically a magnetic sensor, electric field sensor, piezoelectric sensor, pyroelectric sensor, radar, sound wave sensor, gyro sensor, mechanical sensor, sound wave sensor, radiation sensor, chemical reaction sensor, or image sensor. Typical examples of the optical sensor 17 include an optical fiber type acoustic sensor, a pressure sensor, a thermal sensor, a gyro sensor, a distance measuring sensor, a temperature sensor, an acceleration sensor, a speed sensor, an angular velocity sensor, and a gas sensor.

If a sufficient optical distance can be set between the light source 4 and the optical sensor 17, the linear actuator in the present invention can be controlled in a three-dimensional space using an optical gyroscope function utilizing the Sagnac effect due to ring interference. . Furthermore, the sensing position on the light guide line 3 can be specified by utilizing the optical pulse test technique (OTDR).

FIG. 12 shows an example in which the linear actuator according to the present invention is applied to a pair of skeletons 23 via joints 24. The joint 24 is composed of a hemispherical rotor, has a pendulum configuration that tilts in one axial direction with the center of the hemisphere as a base axis, and a stress F is applied to the skeleton 23. Furthermore, two linear actuators Ra and Rb that are opposed to each other via the joint 24 with respect to the rotation center of the joint 24 are arranged so as to connect the skeletons.

With the above-described configuration, the skeleton 24 is driven to tilt clockwise by driving Rb to contract and driving to extend Ra (FIG. 12A). On the other hand, as shown in FIG. 12B, when the skeleton 23 is rotated counterclockwise, Ra is degenerated and Rb is extended. FIG. 12C shows an example in which a constant tilt angle can be maintained even if the direction of the stress F varies by continuing the degenerative drive of the linear actuators Ra and Rb in an arbitrary balance in the present invention.

FIG. 13 illustrates a configuration in which two linear actuators according to the present invention are used so as to intersect with each other so that the skeleton 23 can be driven to rotate and tilt at the same time.
As illustrated in FIG. 13A, the linear actuators Ra and Rb are connected to the skeleton 23 through the indirect 24 having a degree of freedom of movement in the rotation direction and the tilt direction so that the respective attachment positions intersect with each other by 180 degrees. Has been placed. The skeleton 23 is applied with a rotational torque T _f that rotates the skeleton 23 counterclockwise together with the stress F.

Here, when Ra degenerates and Rb maintains a constant degenerative driving force, the skeleton 23 generates a rotational driving force in the clockwise direction simultaneously with the inclining driving in the counterclockwise direction with respect to the indirect 24.
On the other hand, when Rb is degenerated and Ra maintains a constant degenerative driving force, the skeleton 23 generates a rotational driving force in the clockwise direction simultaneously with the tilting drive in the clockwise direction with respect to the indirect 24.

When the indirect 24 is a sphere and operates in all directions, it is possible to control driving in any direction by combining a plurality of linear actuators according to the present invention that combine rotation and tilt, and controlling the amount of contraction and extension, respectively. Become.

As described above, by arranging the linear actuators Ra and Rb so as to intersect each other by 180 degrees, it is possible to simultaneously perform tilt driving in different directions and rotational driving in one direction.
FIG. 14 is a diagram for explaining the specifications of the mathematical formula used when calculating the relationship between the amount of degeneration of the linear actuator Ra attached to the skeleton 23 via the indirect 24 and the tilt angle of the skeleton 23. Note that a configuration in which two bags 1 are connected to the linear actuator Ra is illustrated.

数式７から、リニアアクチュエータの縮退量δと骨格回転角θは数式８の関係で示される。

The points at both ends where the linear actuator in the present invention is fixed to the skeleton are set as B and C, respectively, and the rotation center of the skeleton is set as A. Since the fixed point B of the linear actuator is different from the rotation center position of the skeleton, the skeleton has an inclination corresponding to the angle θ according to the reduction amount δ.
The distance between A and B is L, the distance between A and C is F, the distance between B and C is R, the scissor angle between B, A, and C is θ _k, and the depression angle between A, B, and C is θ _In the case of _F , the relationship of Formula 7 is established.

From Equation 7, the degeneracy amount δ and the skeleton rotation angle θ of the linear actuator are expressed by the relationship of Equation 8.

FIG. 15 shows the result of a trial calculation of the relationship between the amount of degeneration of the linear actuator and the bending angle of the joint in the present invention, using the relational expression as an example of the size approximated to a human arm.
When L = 30 mm, F = 250, and θ _F = 85 degrees, the degeneration rate and the bending angle of the linear actuator have a substantially direct relationship. A bending angle of about 40 degrees can be obtained at the joint by 8% degeneration of the linear actuator.

FIG. 16 shows that ten of the bags 1 are connected and spirally arranged so as to surround the skeleton 23, and the tendon 26 extends along a guide 25 provided at one end of the skeleton 23 near the joint 24. The application example of the linear actuator in this invention which has the structure which slides is shown.
One end of the linear actuator is attached to the skeleton 23 by a bush 8 at one end of the skeleton 23 on the side opposite to the guide 25.

With the above configuration, even when a skeleton having a short overall length is wound, the linear actuator can be spirally wound to increase the overall length of the linear actuator. It becomes possible to drive tilting. In addition, by arranging another linear actuator spirally wound in a direction different from the winding direction at the position indicated by a broken line in FIG. 16, the frame 23 can be tilted and reciprocated.

FIG. 17 shows an application example in which a plurality of linear actuators according to the present invention are arranged on an arm having three joints 24 and four skeletons 23. At least one of the plurality of linear actuators is attached to the skeleton 23 across the two joints 24, and the tendon 26 extends along a guide 25 provided at one end of the skeleton 23 located in the vicinity of the central joint 24. It is arranged to slide.

By using the above configuration, two linear joints can be simultaneously driven by one linear actuator, and the arm shown in FIG. 17A is coupled with the linear actuator arranged across the single joint 24. An operation close to a living body as shown in the transition from the form to the arm form shown in FIG.

In order to make the arm behave more like a human body, it is effective to place it at a site that imitates the arrangement of various muscles of the human body. Specifically, the following muscles are candidates.
Sternocleidomastoid muscle, deltoid muscle, triceps surae, anterior saw flexor, forearm flexor muscles, long adductor, tensor fascia latae muscle, thin muscle, medial vastus muscle, anterior tibialis, gastrocnemius, rectus femoris, lateral Vastus musculoskeletal muscle, adductor muscle, pubic muscle, iliac muscle, external oblique muscle, rectus abdominis, biceps brachii, great pectoral muscle, trapezius, inferior spinal muscle, latissimus dorsi Muscle, biceps femoris, soleus, semi-tendonoid, spine standing muscle, great circular muscle, small circular muscle, ulnar carpal flexor, little finger allele, little abductor, short finger flexor, wormlike muscle, Superficial flexor, deep flexor, long thumb flexor, palmar interosseous muscle, thumb adductor, short thumb abductor, short thumb flexor, thumb allele, flexor carpal flexor, long finger A location corresponding to one or more flexors.

On the other hand, the plurality of linear actuator light guide lines 3 are disposed so as to penetrate the skeleton 23 and the inside of the bush 8. With this configuration, the light guide wire 3 is protected against impact and various damages, and high durability is obtained.

As described above, in particular, in a case where the linear actuator according to the present invention is applied to an arm-like structure arranged so as to straddle one or more joints, a plurality of linear actuators can be arranged while keeping the arm small. Each linear actuator can be controlled independently, and the light source for driving the linear actuator can be supplied using a collection of lightweight optical fibers with a small light guide path diameter, so the distance between the drive light source and the arm must be set large. Even when a light source having a large output is used, the moment of inertia when the arm is driven can be minimized due to the weight of the arm.

FIG. 18 shows an example in which the linear actuator according to the present invention is applied to a humanoid robot hand module simulating the movement of a human arm and hand.
By taking advantage of the characteristics of the linear actuator in the present invention, it is possible to cope with delicate and complicated operations required in a mechanism that imitates a human finger and requires a small group of linear actuators.

On the other hand, the electromagnetic motor 27 can be used as appropriate in a portion that is difficult for humans and that requires a rotational motion. Electric power is supplied to the motor by optical-electrical conversion of energy light transmitted through the optical fiber. The converted electric energy can be used by charging the storage battery to stably drive the electromagnetic motor 25 regardless of the transmission timing of the energy light. Furthermore, the charged electric energy can be utilized as a drive source for an electric heater type linear actuator or a drive source for a sensor.

A part corresponding to the fingertip can be provided with a high-power laser emission function for laser processing in addition to the sensor 22 for pressure sensitivity, heat sensitivity, distance measurement, and the like. Moreover, near infrared laser light is irradiated toward a living body, and image light reflected from the living body is introduced into an image sensor through an array type light guide using a bundle fiber, thereby enabling biometric authentication and inspection of the living body.

When driving a linear actuator in an environment where the radiation concentration is high, such as in a nuclear reactor or outer space, the conventional electric-magnetic motor system can cause damage to the lubricant and electrical wiring system due to the destruction of the polymer due to radiation. There is a problem that the linear actuator cannot be driven due to deterioration.

Also in the case of the linear actuator in the present invention, along with deterioration of the thermal expansion body in the container, defects and impurities in the optical fiber into which the light from the light source is introduced may become a color center and the light guide characteristics may deteriorate. Therefore, when working with a robot arm using a linear actuator under high radiation, a method using a hollow light guide tube as the light guide wire 3 is suitable.

FIG. 19 shows an example in which the linear actuator according to the present invention is used in a hand module of a humanoid robot that can perform an operation similar to that of a human arm and hand. The two skeletons 23 via the joints 24 are joined by the muscles 28, so that the joints can be prevented from being detached, and at the same time, the driving direction of the joints 24 can be restricted.

The skeleton 23 capable of efficiently converting the degeneracy amount of the linear actuator into the angle of the joint 24, the arrangement configuration of the linear actuator in the present invention, the gyro arranged inside the skeleton 23, and the optical type installed in the indirect portion The optical sensor is composed of an angle sensor 17, an optical energy supply to the linear actuator, and a light guide path 3 serving as a transmission path for optical signals supplied from various sensors, and a multiplexer / demultiplexer 15.

It is joined so as to sandwich a lubricant 30 that smoothes the operation of the joint 24. The lubricant 30 has a property of solidifying at a constant temperature. The lubricant 30 has a lubrication state at the time of driving the joint and a solidification state at the time of indirect fixing. Can be selected by control. In the state where the lubrication 30 is solidified, the joint 24 is fixed.

Devices such as the light guide line 3, the multiplexer / demultiplexer 15, the optical sensor 17, and the photoelectric converter, and the wiring are housed inside the skeleton 23, and the durability is ensured and the size is reduced. The linear actuator is terminated by a bush 8 made of ceramics or metal, and is fixed so as to be embedded in the skeleton 23. The light guide wire 3 penetrates the terminal portion and is introduced into the linear actuator. The light guide line 3 is branched by a multiplexer / demultiplexer 15 provided inside the skeleton 23 and introduced into each linear actuator, and the distribution ratio and intensity of the light source are controlled.

The signal of the optical sensor 17 is introduced into the light guide line 3 via the multiplexer / demultiplexer 15 and reaches the control processor. When the signal is an electrical signal, the potential signal is changed into an optical signal near the sensor and introduced into the light guide line 3. When it is necessary to supply electricity to a sensor other than light, the energy light and the signal light multiplexed on the light guide line 3 are separated by the multiplexer / demultiplexer 15 and subjected to photoelectric conversion. The light guide line 3 arranged so as to pass through the joint 24 is led out from the skeleton 23 in the vicinity of the joint 24 and arranged so as to bypass the joint 24.

FIG. 20 shows an example in which an elastic skin 31 is disposed outside the hand module shown in FIG. 19 so as to cover the hand module. The inside of the skin 31 is filled with a solvent 10 for cooling the linear actuator. The solvent 10 filled in the skin 31 can enhance the cooling effect of the linear actuator in the present invention by the stirring by driving the hand module and the diffusion of heat to the outside through the skin 31.
In addition, it cannot be overemphasized that the skin 31 can optimize a composition and a structure suitable for the external conditions where a hand module is set | placed.

FIG. 21 shows an example in which the linear actuator according to the present invention is applied to a foot module for a humanoid robot simulating the motion of a foot centered on a human foot.
60% of over 600 whole body muscles to support the weight, balance the body, allow the upper body to move freely, and to walk and run on complex road surfaces The above is occupied by leg muscles.
For this reason, utilization of the linear actuator in the present invention is suitable for realizing a function equivalent to a foot in a human body.

FIG. 21A shows a skeleton 23, a joint 24, a bag 1, a muscle 26, a guide 25, a linear actuator, and a sensor 22 in a muscle, muscle, and skeletal structure imitating a portion corresponding to a leg muscle from a lower leg muscle in a human body. The arrangement configuration of the optical sensor 17, the light guide line 3, and the multiplexer / demultiplexer 15 is illustrated. Note that the muscles and epidermis are omitted for the sake of simplicity.

In FIG. 21A, the linear actuator according to the present invention corresponding to the long finger extensor and the tendon 26 corresponding to the long extensor key are bushed on the skeleton 23 corresponding to the distal phalanx of the foot. The tendon 26 corresponding to the long extensor is connected to the ribs, the wedge bone and the cubic bone, the second to fifth metatarsals, the second to fifth proximal phalanges, and the second to fifth middles. It is configured to slide along the guide 25 provided at the end of the skeleton 26 corresponding to the phalanx.

Similarly, a linear actuator according to the present invention corresponding to the long thumb extensor and a tendon 26 corresponding to the long thumb extensor are attached to the right side by the bush 8 with a skeleton 23 corresponding to the distal phalanx of the foot. The tendon 26 corresponding to the long thumb extensor is provided on the guide 25 provided at the end of the skeleton 23 corresponding to the rib, the intermediate wedge bone, the medial wedge bone, the first metatarsal bone, and the first proximal phalanx. It is configured to slide along. The guide 25 has a function corresponding to a muscle support band in the human body.

With the above configuration, an operation of lifting the toe of the foot can be performed by the expansion and contraction drive of the bag 1 provided in the portion corresponding to the kneading of the human body. On the other hand, on the right side in FIG. 21A, a bag 1 corresponding to the triceps surae, gastrocnemius and soleus is provided along the skeleton 23 corresponding to the kneading.

These bags 1 are attached to the bush 1 by a tendon 26 provided continuously with the bag 1, a tendon 26 corresponding to the sole flexor muscle, and a skeleton 23 corresponding to the first to fifth distal phalanges. In the same manner as described above, the tendon 26 slides along the guide 25 provided at the end of each skeleton at the intermediate portion until the bush 8 is reached.

In particular, the bag 1 corresponding to the triceps surae and the tendon 26 continuous thereto correspond to the Achilles tendon in the human body, and therefore, the structure of the bag that can obtain a larger expansion / contraction driving force and the material of the bag 1 having strong toughness are used. It is preferable to optimize.

FIG. 21B shows a view of the part corresponding to the leg muscles from the lower leg muscles as seen from the sole side in the human body shown in FIG. Muscles independent of the triceps surae, long finger extensor, long thumb extensor and anterior tibial muscle are arranged on the sole side, and the linear actuator in the present invention is also arranged in the corresponding part it can.

An optical sensor 17 for mainly detecting pressure is connected to the skeleton 23 corresponding to the distal phalanx through an extension of the light guide line 3 that penetrates the bag 1. Further, a non-optical pressure sensor 22 is provided on the skeleton 22 corresponding to the rib. The photoelectric converter of the sensor 22 is housed inside the skeleton 23 at a site corresponding to the tibia.

In FIG. 21 (b), the thumb adductor lateral head is omitted, but a part of the muscle arrangement configuration in the human body can be omitted according to the required function. Of course, it is possible to add the muscle arrangement configuration in the human body so as to complement the movement, and it is also possible to incorporate an operation that does not exist in the human body.

DESCRIPTION OF SYMBOLS 1 Bag 2 Material 3 Light guide line 4 Light source 5 Light absorber 6 Cooling tube 7 Illumination module 8 Bush 9 Catalyst 10 Solvent 11 Photochemical reaction area 12 Gas 13 Wire 14 Joining body 15 Combined / demultiplexer / branch 16 Combined / demultiplexed filter 17 Light Sensor 18 Optical sensor signal light 19 Light receiving module 20 Control processor 21 Photoelectric converter 22 Sensor 23 Skeleton 24 Joint 25 Guide 26 Tendon 27 Electromagnetic motor 28 Muscle 29 Optical waveguide 30 Lubricant 31 Epidermis

Claims (7)

It consists of a bag that is held at both ends and a substance filled inside the bag, and the driving force is increased by changing the distance between the holding parts by enlarging or reducing the volume of the substance inside the filled bag. A linear actuator characterized by being obtained. The method of inflating and shrinking a material filled in a bag is characterized in that light introduced into the container by a light guide wire or light guide is absorbed by a substance in the container, The linear actuator according to 1. The material filled in the container is composed of a material mainly contributing to absorption of light energy introduced into the container and a material mainly contributing to expansion and contraction. The linear actuator described. These arms have two or more arms that are arranged so as to be in close contact with the first material and have a second material having a smaller expansion coefficient than that of the first material. In a U-shaped or / and spiral-shaped joined body having a mechanism for holding between the parts, the temperature of the U-shaped or / and spiral shaped joined body is raised / lowered by light irradiation to change the distance between the holding parts in a straight line. A linear actuator characterized by being converted into motion and driven. 2. The linear actuator according to claim 1, wherein the linear actuator according to claim 1 is composed of a catalyst or / and medium that promotes a photochemical reaction, and a solvent that generates a vaporization or liquefaction reaction by the photochemical reaction as a material filled in the container. One or more optical sensors, one or more magnetic sensors, one or more electric field sensors, one or more piezoelectric sensors, one or more pyroelectric sensors at the end of the light beam or light guide or in the middle thereof One or more radars, one or more acoustic sensors, one or more gyro sensors, one or more mechanical sensors, one or more acoustic sensors, one or more radiation sensors, one or more chemical reaction sensors, one The linear actuator according to claim 2, comprising one or more types of sensors among the two or more image sensors. In one or more bags, both ends of which are fixed to the structure via one or more links and are held under tension, the end or / and middle part of the bag is filled with a substance. The portion connected to the bag slides along one or more guides provided on a structure having one or more links on which the bag is held and has a portion connected to the bag. The linear actuator according to claim 1, comprising:

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