CN111975759A - An optical sensor-embedded artificial muscle and its use and preparation method - Google Patents

Abstract

The invention discloses an optical sensor-embedded artificial muscle and its use and preparation method. The current feedback control of pneumatic muscle actuation systems mainly relies on the use of external pressure sensors and position sensors or encoders. The present invention includes an optical pressure detection end cap, an artificial muscle base and an optical length detection end cap. The artificial muscle base includes an elastic cylinder, an optical length detection diaphragm and an optical pressure detection diaphragm. The optical pressure detection diaphragm and the optical length detection diaphragm are respectively fixed on the pressure detection end and the length detection end of the inner cavity of the elastic cylinder body. The two sides of the optical pressure detection diaphragm are not connected. The two sides of the optical length detection film are communicated through the ventilation holes. The inner side of the elastic barrel absorbs light. The outer sides of the light pressure detection film and the light length detection film reflect light. The present invention feedbacks the contraction length and contraction force of the artificial muscle by designing an optical sensor, and has the advantages of light weight, good compliance and the like.

Description

An optical sensor-embedded artificial muscle and its use and preparation method

technical field

The invention belongs to the technical field of soft robots, in particular to a soft pneumatic artificial muscle embedded with an optical sensor.

Background technique

The field of soft robotics is well-positioned for wearables and human-robot interaction due to its light weight and compliance. For such applications, the perception of position and force is crucial for enhancing human-computer interaction, and implementing these functions in soft-body systems is a challenge due to the nonlinear nature of soft-body materials. The current feedback control of pneumatic muscle actuation systems mainly relies on the use of external pressure sensors and position sensors or encoders. While this works for some robotic systems, additional sensing hardware adds complexity to the design and negates the advantages of soft robotics in terms of light weight, compliance, and more. Especially in the case of wearable devices, external sensing may add bulk and weight to the wearer and inhibit movement.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a soft pneumatic artificial muscle embedded with an optical sensor.

The invention relates to an optical sensor-embedded artificial muscle, comprising an optical pressure detection end cap, an artificial muscle base and an optical length detection end cap. Two ends of the artificial muscle base are respectively a pressure detection end and a length detection end. The optical pressure detection end cap and the optical length detection end cap are respectively installed on the pressure detection end and the length detection end of the artificial muscle base. The artificial muscle base includes an elastic cylinder, an optical length detection diaphragm and an optical pressure detection diaphragm. The optical pressure detection diaphragm and the optical length detection diaphragm are respectively fixed on the pressure detection end and the length detection end of the inner cavity of the elastic cylinder body. The two sides of the optical pressure detection diaphragm are not connected. The two sides of the optical length detection film are communicated through the ventilation holes. The inner side of the elastic barrel absorbs light. The outer sides of the light pressure detection film and the light length detection film reflect light. An optical pressure detection sensor is installed on the inner side of the optical pressure detection end cap. An optical length detection sensor is installed on the inner side of the optical length detection end cap. Both the optical pressure detection sensor and the optical length detection sensor are capable of emitting light and capable of detecting the received light intensity.

Preferably, the artificial muscle matrix further includes a limiting ring and a reinforcing fiber mesh. The reinforced fiber mesh is inlaid inside the side wall of the elastic cylinder, and the elastic cylinder is divided into an outer cylinder and an inner cylinder. A plurality of limit rings arranged in sequence are embedded in the side wall of the pressure detection end of the elastic cylinder to limit the deformation of the pressure detection end of the elastic cylinder. The light pressure detection diaphragm is located at the edge of the part of the elastic barrel limited by the limit ring.

Preferably, the reinforced fiber mesh and the limiting ring are formed by winding Kevlar fibers. The reinforcing fiber web is formed by interlacing two sets of helical threads with opposite directions of rotation.

Preferably, the light-absorbing material is a mixture of platinum-cured silica gel and black organic silicone pigment; the light-reflecting material is a mixture of platinum-cured silica gel and white organic silicone pigment.

Preferably, the optical pressure detection end cap and the optical length detection end cap both include basic end cap assemblies with the same structure. The basic end cap assembly includes an end connector, a cap and a shielded aluminum plate. The main body of the end connector is cylindrical, and a plurality of threading blocks are arranged at the edge of the inner end. Each threading block is provided with threading holes. The fiber threads at both ends of the reinforced fiber web are respectively passed through the respective thread holes on the two end connectors. The cover is secured in the end connector. The shielding aluminum plate is fixed on the inner side of the cover body. The optical pressure detection sensor and the optical length detection sensor have the same structure, and both include light-emitting diodes and photodiodes. Light-emitting diodes and photodiodes are respectively installed on both sides of the corresponding shielding aluminum plate.

Preferably, a light absorption ring is provided at the outer edge of the light length detection film;

Preferably, two light guides are installed on the inner side of the optical length detection end cap. The light-emitting position and the light-receiving position of the two light guides and the optical length detection sensor. The optical pressure detection end cap or the optical length detection end cap is provided with a trachea; the two ends of the trachea are respectively connected with the inner cavity and the gas source of the artificial muscle base.

The method of using the artificial muscle embedded in the optical sensor is as follows:

Step 1: Calibrate the optical pressure detection sensor and the optical length detection sensor.

Step 2: Use soft pneumatic artificial muscles to drive in continuous detection.

2-1. Put the soft pneumatic artificial muscle into the mechanical system as the power source;

2-2. The light-emitting diodes in the optical pressure sensor and the optical length sensor continue to emit light in a divergent shape. Photodiode.

2-3 Drive the expansion and contraction of the soft pneumatic artificial muscle by inflating and deflating the soft pneumatic artificial muscle. When the soft pneumatic artificial muscle is shortened, the distance between the optical length detection diaphragm and the optical length sensor decreases, which in turn increases the light intensity detected by the photodiode in the optical length sensor, which is derived from the light intensity value detected by the optical length sensor. The current length of the soft body pneumatic artificial muscle.

When the pressure in the soft pneumatic artificial muscle increases, the protruding range of the optical pressure detection diaphragm to the optical pressure sensor increases, which in turn reduces the light intensity detected by the photodiode in the optical pressure sensor. The current internal pressure of the soft-bodied pneumatic artificial muscle is derived from the light intensity value of .

Preferably, a specific process of step one of the method for using the artificial muscle embedded in the optical sensor is as follows:

1-1. Fill the muscle with gas with gradual pressure through the combination of proportional valve and solenoid valve, and the pressure is collected by the pressure sensor; during the whole test process, the length, internal pressure and optical pressure of the software pneumatic artificial muscle are continuously recorded The light intensity detected by the photodiode in the detection sensor, optical length detection sensor.

1-2. Through discrete point fitting, the light-pressure relationship curve between the light intensity detected by the optical pressure detection sensor and the internal pressure of the soft pneumatic artificial muscle, and the light intensity detected by the optical length detection sensor and the soft pneumatic artificial muscle are obtained. Light-length relationship curve between the lengths of the muscles.

The preparation method of the optical sensor-embedded artificial muscle is as follows:

Step 1. Use a vertically arranged cylindrical inner mold and a cylindrical first outer mold to cooperate to form a mold cavity for pouring the inner barrel; the inner side of the first outer mold is provided with a grid-like protrusion, and one end of the inner side is The ends are provided with multiple rings of protrusions. The light-absorbing material is poured between the inner mold and the first outer mold to form an inner barrel; the outer side of the inner barrel is provided with a grid-shaped groove, and one end is provided with a plurality of annular grooves. The grid-like grooves are formed by interweaving a plurality of left-handed spirals and a plurality of right-handed spirals. Both ends of the outer side surface of the inner cylinder body have a plurality of intersection points of the left-handed helix and the right-handed helix.

Step 2: Put the two end connectors on both ends of the inner mold and fix them with positioning pins, so that the multiple threading holes on the end connectors are against the multiple intersections of the spiral lines at the end of the inner barrel. Wrap a fiber thread along the grid grooves on the inner barrel so that the Kevlar fiber thread passes through all locations of the grid grooves and through all the threading holes of the two end connectors. A plurality of limit rings are then wound around the fiber line.

Step 3: Remove the first outer mold, and install a second outer mold with an inner diameter larger than the first outer mold; use light-absorbing material to pour between the inner barrel and the second outer mold to form an outer barrel; the outer barrel is completely covered fiber line. The inner cylinder body and the outer cylinder body together form an elastic cylinder body; the inner mold is taken out from the elastic cylinder body. At this time, the length detection end in the elastic cylinder body is set downward.

Step 4. Casting the optical length detection diaphragm: put the first diaphragm mold with the exhaust pin at the length detection end under the elastic cylinder body; the edge of the end of the first diaphragm mold is provided with an annular protrusion; then A reflective material is poured at the first diaphragm mold to form an optical length detection diaphragm; after the optical length detection diaphragm is cured, the elastic cylinder is turned over so that the annular groove on the outer side of the optical length detection diaphragm is set upward, and the removal Lower the first diaphragm mold, and pour light-absorbing material into the annular groove on the outer side of the light-length detecting diaphragm to form a light-absorbing ring.

Step 5. Casting the optical pressure detection diaphragm: insert the pressure detection end under the elastic cylinder into the second diaphragm mold with flat end surface; then pour the reflective material through the syringe at the second diaphragm mold to form the optical pressure detection diaphragm.

Step 6: Completely install the optical pressure detection end cap and the optical length detection end cap to both ends of the elastic barrel.

The beneficial effects that the present invention has are:

1. The present invention provides an optical sensor-embedded soft pneumatic artificial muscle. By designing an optical sensor, the contraction length and contraction force of the artificial muscle can be fed back. Compared with the existing artificial muscle that feeds back information through external sensing hardware, It has the advantages of light weight and good compliance, especially in the case of wearable devices, which greatly reduces the size and load of the wearer, making it lighter.

2. The present invention converts the internal pressure of the artificial muscle into the bending deformation degree of the optical pressure detection diaphragm, and judges the bending deformation degree of the optical pressure detection diaphragm by reflecting the light intensity of the optical pressure detection diaphragm to the optical pressure detection sensor, The detection of the internal pressure of the artificial muscle is realized.

3. The present invention converts the length of the artificial muscle into the distance from the optical length detection diaphragm to the end, and judges the distance from the optical length detection diaphragm to the end by the light intensity reflected from the optical pressure detection diaphragm to the optical pressure detection sensor. , to realize the length detection of artificial muscles.

4. The optical electronic components of the artificial muscle of the present invention can easily enter and exit the muscle, can be disassembled and replaced, and have high reusability, which greatly reduces the cost. In addition, the optical sensor does not have the common oxidation or leakage problems of conductive liquid sensors, and has high safety.

5. The artificial muscle of the present invention has a wide range of applications, overcomes the nonlinear characteristics of soft materials, and can be applied to fields such as mechanical arms, soft robots, and medical rehabilitation equipment.

Description of drawings

Fig. 1 is the overall structure schematic diagram of the present invention;

Fig. 2 is the side schematic diagram after expansion of the present invention;

Fig. 3 is the explosion schematic diagram of the present invention;

4a is a schematic diagram of the internal structure of the artificial muscle matrix in the present invention;

4b is a schematic structural diagram of an optical length detection film in the present invention;

5 is an exploded view of the end cover of the optical length sensor in the present invention;

6 is an exploded view of the end cover of the optical pressure sensor in the present invention;

7 is a schematic diagram of the present invention from an initial state to an expanded state;

FIG. 8 is a schematic flow chart of the preparation method of the present invention.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings.

As shown in Figures 1 and 2, an optical sensor-embedded soft pneumatic artificial muscle includes an optical pressure detection end cap 1, an artificial muscle base 2 and an optical length detection end cap 3. The artificial muscle base 2 is cylindrical, and will expand along the radial direction and shorten in length after being inflated with gas. Two ends of the artificial muscle base 2 are a pressure detection end and a length detection end, respectively. The optical pressure detection end cap 1 and the optical length detection end cap 3 are respectively installed on the pressure detection end and the length detection end of the artificial muscle base 2 , and are respectively used to detect the pressure and overall length of the artificial muscle base 2 .

As shown in FIGS. 3 and 4 a , the artificial muscle base 2 includes an elastic cylinder 4 , a limit ring 5 , a reinforced fiber mesh 6 , an optical length detection diaphragm 8 and an optical pressure detection diaphragm 7 . The reinforcing fiber mesh 6 is embedded inside the side wall of the elastic cylinder 4, and divides the elastic cylinder 4 into an outer cylinder 4-1 and an inner cylinder 4-2. The outer cylinder body 4-1 and the inner cylinder body 4-2 are formed by pouring twice, and are tightly fixed together. The reinforcing fiber mesh 6 can increase the strength of the artificial muscle base 2 and avoid local large deformation of the artificial muscle base 2 . The four limit rings 5 arranged in sequence are embedded in the side wall of the pressure detection end of the elastic cylinder 4 to limit the deformation of the elastic cylinder 4, so that the shape of the pressure detection end of the elastic cylinder 4 remains unchanged before and after inflation. The reinforcing fiber mesh 6 and the limiting ring 5 are both formed by winding Kevlar fibers. The reinforcing fiber web 6 is formed by interlacing two sets of eight helical threads with opposite directions of rotation, and is formed by winding one fiber thread.

As shown in Figures 4a and 4b, the optical pressure detection diaphragm 7 and the optical length detection diaphragm 8 are respectively fixed on the pressure detection end and the length detection end of the inner cavity of the elastic cylinder 4, and both have a distance from the end, which is the light source. Propagation and reflection leave room. The optical pressure detection diaphragm 7 is located at the edge of the part of the elastic cylinder 4 restricted by the limit ring 5, and will not be stretched as the elastic cylinder 4 expands; the optical pressure detection diaphragm 7 separates the elastic cylinder 4 into There are two independent chambers, and the pressures in the two chambers can be different, so the optical pressure detection diaphragm 7 will undergo concave-convex deformation with the change of the internal pressure of the elastic cylinder 4 .

The edge of the optical length detection diaphragm 8 is provided with a vent hole 13, so that the pressures on both sides of the optical length detection diaphragm 8 are kept the same, so the optical length detection diaphragm 8 will be stretched with the expansion of the elastic cylinder 4, and will not The concave-convex deformation will occur with the change of the internal pressure of the elastic cylinder 4 . A light-absorbing ring 12 is provided on the outer side edge of the light length detecting film 8 ; the elastic barrel 4 and the light-absorbing ring 12 are all made of light-absorbing material. Both the light pressure detection film 7 and the light length detection film 8 are made of reflective materials. Since the part of the light length detection diaphragm 8 in contact with the inner wall of the elastic cylinder 4 will produce uncontrollable deformation when the air cavity expands, the light absorption ring 12 can reduce the amount of reflected light reflected to the photodiodes 14-215 at the uncontrollable deformation, thereby improving the sensor performance. response effect;

The light absorbing material is a mixture of platinum cured silica gel (Smooth-On Dragon skin) and black silicone pigment (SilcPig), which can absorb light (infrared light) to a great extent, reduce optical reflectance, and prevent ambient infrared light from affecting optics Sensor light signal; a mixture of reflective material platinum-cured silicone and white silicone pigment to maximize the optical reflectivity of the diaphragm. The mass fraction of the silicone pigment in the light-absorbing material and the light-reflecting material is both 3%

As shown in FIGS. 5 and 6 , both the optical pressure detection end cap 1 and the optical length detection end cap 3 include basic end cap assemblies with the same structure. The basic end cap assembly includes an end connector 9 , a cover body 10 and a shielding aluminum plate 11 . The main body of the end connector 9 is cylindrical, and eight threading blocks are arranged at the inner edge. The eight threading blocks are all provided with threading holes. The fiber lines at both ends of the reinforced fiber mesh 6 pass through the threading holes on the two end connectors 9 respectively to realize the fixation of the optical pressure detection end cap 1 and the optical length detection end cap 3 and the artificial muscle base 2 . The cover 10 is fixed in the end connector 9 for closing the end of the artificial muscle base 2 . The shielding aluminum plate 11 is fixed on the inner side of the cover body 10 , and separates the inner side of the cover body 10 into a light-emitting area and a light-receiving area that do not interfere with each other. The side wall of the end connector 9 is provided with a positioning hole 16 for positioning the mold during artificial muscle casting. A closing plate 17 is provided on the outer side of the cover body 10 .

An optical pressure detection sensor 14 and an optical length detection sensor 15 are installed in the optical pressure detection end cap 1 and the optical length detection end cap 3, respectively. The optical pressure detection sensor 14 and the optical length detection sensor 15 have the same structure, and both include a light-emitting diode 14-1 and a photodiode 14-2. The light emitting diodes 14 - 1 and the photodiodes 14 - 2 are respectively installed on both sides of the corresponding shielding aluminum plate 11 . The shielding aluminum plate can prevent the light emitted from the side of the light emitting diode 14-1 from directly entering the photodiode 14-2. The light emitting diode 14-1 is used to emit light; the photodiode 14-2 is used to receive and detect the intensity of the light reflected by the light pressure detection diaphragm 7 or the light length detection diaphragm 8, and judge the artificial muscle according to the received light intensity of internal pressure and length.

Two light guide members 18 are also installed on the inner side of the optical length detection end cover 3 . The light guide member 18 uses an optical fiber. The two light guides 18 are aligned with the light-emitting diode 14-1 and the photodiode 14-2 in the optical length detection sensor 15, respectively, so as to extend the light source divergence point of the optical length detection sensor 15, so as to avoid the muscles near the end cap when the air cavity expands. The stretching is uneven, which hinders the propagation of light.

The optical pressure detection end cap 1 or the optical length detection end cap 3 is provided with a trachea 19; the two ends of the trachea 19 are respectively connected with the inner cavity and the air source of the artificial muscle base 2 to realize the inflation and deflation of the artificial muscle base 2, thereby realizing Actuation of artificial muscles.

As shown in Figure 7, the detection principle of the present invention is as follows:

When the overall length of the artificial muscle base 2 is shortened due to gas filling or changes in external load, the part of the artificial muscle base 2 except the position limited by the limit ring 5 is shortened proportionally. At this time, the optical length detection diaphragm 8. The distance from the optical length sensor decreases; since the light emitted by the photodiode 14-2 is emitted in a diverging shape, the farther the light travels, the larger the light coverage is, and the smaller the light intensity per unit area, so when the light When the distance between the length detection diaphragm 8 and the optical length sensor decreases, the propagation distance of the light decreases, and the light intensity detected by the photodiode 14-2 increases (that is, the difference between the light intensity received by the optical length sensor and the length of the artificial muscle base 2). is a monotonically decreasing function relationship); according to this relationship, the length of the artificial muscle base 2 can be calculated.

When the internal air pressure of the artificial muscle base 2 increases due to gas filling or external load changes, the pressure difference between the two sides of the optical pressure detection diaphragm 7 increases, and the optical pressure detection diaphragm 7 protrudes toward the optical pressure sensor. increase, that is, the curvature of the outer convex surface of the optical pressure detection diaphragm 7 increases; the light emitted by the optical pressure sensor tends to be more dispersed when reflected by the optical pressure detection diaphragm 7, so that the light intensity detected by the photodiode 14-2 decreases (That is, the relationship between the light intensity received by the optical pressure sensor and the internal pressure of the artificial muscle base 2 is a monotonically increasing function); according to this relationship, the internal pressure of the artificial muscle base 2 can be calculated.

The method of using the software pneumatic artificial muscle embedded in the optical sensor is as follows:

Step 1: Calibrate the optical pressure detection sensor 14 and the optical length detection sensor 15 .

1-1. Perform multiple sets of no-load tests on the soft pneumatic artificial muscle to characterize the response of the optical length sensor and the pressure sensor, as well as the muscle contraction range. The optical pressure detection end cap 1 is suspended so that the artificial muscle base 2 is vertically arranged, and the optical length detection sensor 15 is fixed on the free end of the muscle.

1-2. The inside of the muscle is inflated with gas with a gradual pressure gradient through a combination of proportional valve and solenoid valve (and preloaded to 1 standard atmosphere before pressurization to eliminate any slack in the test setup), the air pressure is passed through the air pressure sensor Acquisition: During the whole testing process, the length of the software pneumatic artificial muscle, the internal pressure, the optical pressure detection sensor 14 and the light intensity detected by the photodiode 14-2 in the optical length detection sensor 15 are continuously recorded.

1-3. Through discrete point fitting, the light-pressure relationship curve between the light intensity detected by the optical pressure detection sensor 14 and the internal pressure of the soft pneumatic artificial muscle, and the light intensity detected by the optical length detection sensor 15 and the software Light-length relationship curve between the lengths of pneumatic artificial muscles. In the subsequent detection process, the light intensity detected by the optical pressure detection sensor 14 and the optical length detection sensor 15 are respectively taken on the light-pressure relationship curve and the light-length relationship curve to obtain the length of the corresponding software pneumatic artificial muscle. , Internal pressure.

1-4. The occlusion force test was performed on the soft pneumatic artificial muscle to characterize the relationship between muscle contraction force and length. In order to measure the force, the muscle is connected to a mechanical test system, the optical length detection end cap 3 is fixed on the base of the test bench, the optical pressure detection end cap 1 is connected to the mechanical push rod, and a pressure sensor is connected in between to test and collect the push rod force, which is equivalent to In each test, the mechanical push rod pushes the muscle at a certain speed, the air pressure in the muscle is constant, and the relationship between the muscle contraction force and length is recorded; the air pressure is changed in turn, and the experiment is successfully calibrated after repeated experiments.

Step 2: Use soft pneumatic artificial muscles to drive in continuous detection.

2-1. Put the soft pneumatic artificial muscle into the mechanical system as the power source;

2-2. The light-emitting diodes 14-1 in the optical pressure sensor and the optical length sensor continue to emit light in a divergent shape. Photodiode 14-2 in the optical length sensor.

2-3 Drive the expansion and contraction of the soft pneumatic artificial muscle by inflating and deflating the soft pneumatic artificial muscle through the air source. When the soft pneumatic artificial muscle is shortened, the distance between the optical length detection diaphragm 8 and the optical length sensor decreases, thereby increasing the light intensity detected by the photodiode 14-2 in the optical length sensor. The intensity value and the light-pressure relationship curve obtained in step 1 obtain the current length of the soft-bodied pneumatic artificial muscle.

When the pressure in the soft pneumatic artificial muscle increases, the protruding extent of the optical pressure detection diaphragm 7 toward the optical pressure sensor increases, thereby reducing the light intensity detected by the photodiode 14-2 in the optical pressure sensor. The light intensity value detected by the pressure sensor and the light-length relationship curve obtained in step 1 are used to obtain the current internal pressure of the soft pneumatic artificial muscle.

As shown in Figure 8, the preparation method of the optical sensor-embedded soft pneumatic artificial muscle is as follows:

Step 1. Use a vertically arranged cylindrical inner mold 20 and a cylindrical first outer mold 21 to cooperate to form a mold cavity for pouring the inner barrel 4-2; the inner side of the first outer mold 21 is provided with a mesh There are four circles of protrusions at one end of the inner side surface. The light-absorbing material is poured between the inner mold 20 and the first outer mold 21 to form an inner barrel 4-2; the outer side of the inner barrel 4-2 has grid-shaped grooves, and one end has four annular grooves. The grid-like grooves are interwoven by eight left-handed and eight right-handed spirals. There are eight intersection points of the left-handed helix and the right-handed helix at both ends of the outer side surface of the inner cylinder body 4-2.

Step 2: Put the two end connectors 9 on both ends of the inner mold 20 and fix them with positioning pins, so that the eight threading holes on the end connectors 9 are against the eight spiral lines at the end of the inner barrel 4-2. intersection. Wrap a Kevlar thread along the mesh grooves on the inner barrel so that the Kevlar thread passes through all locations of the mesh grooves and through all of the two end connectors 9 needle. Then four limit rings 5 are wound with Kevlar fibers.

Step 3: Remove the first outer mold 21, and install a second outer mold 22 with an inner diameter larger than the first outer mold 21; use light-absorbing material to pour between the inner barrel 4-2 and the second outer mold 22 to form an outer barrel Body 4-1; outer body 4-1 completely covered with Kevlar fiber. The inner cylinder body 4-2 and the outer cylinder body 4-1 together form the elastic cylinder body 4. After the silica gel is cured, the positioning pin is pulled out, and the inner mold 20 is taken out from the elastic cylinder body 4. At this time, the length detection end in the elastic cylinder body 4 is set downward.

Step 4. Casting the optical length detection diaphragm 8: put the first diaphragm mold 24 with the exhaust pin 23 at the length detection end below the elastic cylinder 4; the end edge of the first diaphragm mold 24 is provided with Then, the reflective material is poured through the syringe at the first diaphragm mold 24 to form the optical length detection diaphragm 8; after the optical length detection diaphragm 8 is cured, the elastic cylinder 4 is turned over, so that the optical length detection diaphragm 8 is outside the The annular groove on the side is set upward, the first diaphragm mold 24 is removed, and light-absorbing material is poured into the annular groove on the outer side of the optical length detection diaphragm 8 to form the light-absorbing ring 12 . Finally, the exhaust pin 23 is removed.

Step 5. Casting the optical pressure detection diaphragm 7: insert the second diaphragm mold 25 with a flat end face at the pressure detection end under the elastic cylinder 4; then pour the reflective material through the syringe at the second diaphragm mold 25 to form the optical pressure Detect the diaphragm 7; remove the second diaphragm mold 25 after curing.

Step 6: Repair the holes left on the elastic cylinder body 4 during injection and pouring; install the optical pressure detection end cap 1 and the optical length detection end cap 3 on both ends of the elastic cylinder body 4 completely; The connection between the body 4 and the optical pressure detection end cap 1 and the optical length detection end cap 3 is sealed.

Claims (10)

1. An optical sensor embedded artificial muscle comprises an artificial muscle base body (2); the method is characterized in that: the device also comprises an optical pressure detection end cover (1) and an optical length detection end cover (3); two ends of the artificial muscle matrix (2) are respectively a pressure detection end and a length detection end; the optical pressure detection end cover (1) and the optical length detection end cover (3) are respectively arranged at the pressure detection end and the length detection end of the artificial muscle matrix (2); the artificial muscle matrix (2) comprises an elastic cylinder body (4), an optical length detection diaphragm (8) and an optical pressure detection diaphragm (7); the optical pressure detection diaphragm (7) and the optical length detection diaphragm (8) are respectively fixed at the pressure detection end and the length detection end of the inner cavity of the elastic cylinder body (4); the two sides of the light pressure detection diaphragm (7) are not communicated; the two sides of the optical length detection membrane (8) are communicated through a vent hole (13); the inner side surface of the elastic cylinder body (4) absorbs light; the outer side surfaces of the light pressure detection diaphragm (7) and the light length detection diaphragm (8) are reflective; an optical pressure detection sensor (14) is arranged on the inner side of the optical pressure detection end cover (1); an optical length detection sensor (15) is arranged on the inner side of the optical length detection end cover (3); both the optical pressure detection sensor (14) and the optical length detection sensor (15) are capable of emitting light and detecting the intensity of received light.

2. An optical sensor embedded artificial muscle according to claim 1, wherein: the artificial muscle matrix (2) also comprises a spacing ring (5) and a reinforcing fiber net (6); the reinforced fiber net (6) is embedded in the side wall of the elastic cylinder body (4) to divide the elastic cylinder body (4) into an outer cylinder body (4-1) and an inner cylinder body (4-2); the plurality of limiting rings (5) which are sequentially arranged are all embedded in the side wall of the pressure detection end of the elastic cylinder body (4) to limit the deformation of the pressure detection end of the elastic cylinder body (4); the light pressure detection diaphragm (7) is positioned at the edge of the part of the elastic cylinder body (4) limited by the limiting ring (5).

3. An optical sensor embedded artificial muscle according to claim 1, wherein: the reinforcing fiber net (6) and the limiting ring (5) are formed by winding Kevlar fiber wires; the reinforcing fiber net (6) is formed by interweaving two groups of spiral lines with opposite rotation directions.

4. An optical sensor embedded artificial muscle according to claim 1, wherein: the light absorption material is a mixture of platinum-cured silica gel and black organic silicone pigment; the light reflecting material is a mixture of platinum-cured silica gel and a white organic silicone pigment.

5. An optical sensor embedded artificial muscle according to claim 1, wherein: the optical pressure detection end cover (1) and the optical length detection end cover (3) both comprise basic end cover components with the same structure; the basic end cover assembly comprises a terminal connector (9), a cover body (10) and a shielding aluminum plate (11); the main body of the end connector (9) is cylindrical, and a plurality of threading blocks are arranged at the edge of the inner end of the end connector; each threading block is provided with a threading hole; fiber wires at two ends of the reinforced fiber net (6) respectively pass through the threading holes on the two end connectors (9); the cover body (10) is fixed in the end connector (9); the shielding aluminum plate (11) is fixed on the inner side of the cover body (10); the optical pressure detection sensor (14) and the optical length detection sensor (15) have the same structure and respectively comprise a light-emitting diode (14-1) and a photodiode (14-2); the light emitting diode (14-1) and the photodiode (14-2) are respectively arranged on two sides of the corresponding shielding aluminum plate (11).

6. An optical sensor embedded artificial muscle according to claim 1, wherein: and the edges of the outward side surfaces of the optical length detection membranes (8) are provided with light absorption rings (12).

7. An optical sensor embedded artificial muscle according to claim 1, wherein: two light guide pieces (18) are further mounted on the inner side of the optical length detection end cover (3); the light emitting position and the light receiving position of the two light guide members (18) and the optical length detection sensor (15); an air pipe (19) is arranged on the optical pressure detection end cover (1) or the optical length detection end cover (3); two ends of the air pipe (19) are respectively connected with the inner cavity of the artificial muscle matrix (2) and an air source.

8. The method of using an optical sensor embedded artificial muscle according to claim 1, wherein:

calibrating an optical pressure detection sensor (14) and an optical length detection sensor (15);

step two, using soft pneumatic artificial muscles to drive in the continuous detection;

2-1, filling the soft pneumatic artificial muscle into a mechanical system as a power source;

2-2, light emitting diodes (14-1) in the optical pressure sensor and the optical length sensor continuously emit light rays in a divergent shape, and the two groups of light rays are respectively reflected by the optical pressure detection diaphragm (7) and the optical length detection diaphragm (8) and enter the photodiodes (14-2) in the optical pressure sensor and the optical length sensor;

2-3, driving the flexible pneumatic artificial muscle to stretch by inflating and deflating the pneumatic artificial muscle; when the soft pneumatic artificial muscle is shortened, the distance from the optical length detection diaphragm (8) to the optical length sensor is reduced, so that the light intensity detected by a photodiode (14-2) in the optical length sensor is increased, and the current length of the soft pneumatic artificial muscle is deduced according to the light intensity value detected by the optical length sensor;

when the pressure in the soft pneumatic artificial muscle is increased, the protruding amplitude of the light pressure detection diaphragm (7) towards the optical pressure sensor is increased, so that the light intensity detected by a photodiode (14-2) in the optical pressure sensor is reduced, and the current internal pressure of the soft pneumatic artificial muscle is deduced according to the light intensity value detected by the optical pressure sensor.

9. The use method of an optical sensor embedded artificial muscle according to claim 8, wherein: the specific process of the step one is as follows:

1-1, filling air with gradually changed air pressure into muscles through a combination of a proportional valve and an electromagnetic valve, and collecting the air pressure through an air pressure sensor; in the whole testing process, the length, the internal pressure, the optical pressure detection sensor (14) and the light intensity detected by a photodiode (14-2) in the optical length detection sensor (15) of the soft pneumatic artificial muscle are continuously recorded;

1-2, obtaining a light-pressure relation curve between the light intensity detected by the optical pressure detection sensor (14) and the internal pressure of the soft pneumatic artificial muscle and a light-length relation curve between the light intensity detected by the optical length detection sensor (15) and the length of the soft pneumatic artificial muscle through discrete point fitting.

10. The method for preparing an optical sensor embedded artificial muscle as claimed in claim 1, wherein:

step one, forming a die cavity for pouring an inner cylinder body (4-2) by matching a vertically arranged cylindrical inner die (20) with a cylindrical first outer die (21); the inner side surface of the first outer die (21) is provided with grid-shaped bulges, and the end part of one end of the inner side surface is provided with a plurality of circles of bulges; pouring a light-absorbing material between the inner mold (20) and the first outer mold (21) to form an inner barrel body (4-2); the outer side surface of the inner cylinder body (4-2) is provided with a latticed groove, and one end of the inner cylinder body is provided with a plurality of circles of annular grooves; the latticed grooves are formed by interweaving a plurality of left-handed spiral lines and a plurality of right-handed spiral lines; the end parts of the two ends of the outer side surface of the inner barrel body (4-2) are respectively provided with a plurality of intersection points of the left-handed spiral line and the right-handed spiral line;

sleeving two end connectors (9) on two ends of the inner mold (20) and fixing the two end connectors through positioning pins, so that a plurality of threading holes in the end connectors (9) are abutted against a plurality of spiral line intersection points at the end part of the inner cylinder body (4-2); winding a fiber line along the latticed grooves on the inner barrel body, so that the Kevlar fiber line passes through all the positions of the latticed grooves and passes through all the threading holes of the two end connectors (9); then winding a plurality of limiting rings (5) by using fiber wires;

step three, removing the first outer die (21), and installing a second outer die (22) with the inner diameter larger than that of the first outer die (21); pouring a light-absorbing material between the inner cylinder (4-2) and the second outer die (22) to form an outer cylinder (4-1); the outer cylinder body (4-1) completely covers the fiber line; the inner cylinder body (4-2) and the outer cylinder body (4-1) together form an elastic cylinder body (4); taking the inner mold (20) out of the elastic cylinder body (4); at the moment, the length detection end in the elastic cylinder body (4) is arranged downwards;

step four, casting an optical length detection diaphragm (8): a first membrane mould (24) with an exhaust pin (23) is placed at the length detection end below the elastic cylinder body (4); an annular bulge is arranged at the edge of the end part of the first membrane mould (24); then pouring a reflective material at the first membrane mould (24) through an injector to form the optical length detection membrane (8); after the optical length detection diaphragm (8) is solidified, the elastic barrel body (4) is turned over, so that an annular groove on the outer side surface of the optical length detection diaphragm (8) is arranged upwards, the first diaphragm mold (24) is disassembled, and light absorption materials are poured in the annular groove on the outer side surface of the optical length detection diaphragm (8) to form a light absorption ring (12);

step five, casting a light pressure detection diaphragm (7): a second diaphragm die (25) with a flat end face is inserted into the pressure detection end below the elastic cylinder body (4); then pouring a reflective material at the second membrane mould (25) through an injector to form the light pressure detection membrane (7);

and sixthly, completely installing the optical pressure detection end cover (1) and the optical length detection end cover (3) at two ends of the elastic cylinder body (4).

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