CN114700975B

CN114700975B - Flexible optical waveguide-based attitude sensor and robot

Info

Publication number: CN114700975B
Application number: CN202210374864.4A
Authority: CN
Inventors: 赵慧婵; 周婧祎; 刘辛军
Original assignee: Tsinghua University
Current assignee: Tsinghua University
Priority date: 2022-04-11
Filing date: 2022-04-11
Publication date: 2023-10-10
Anticipated expiration: 2042-04-11
Also published as: CN114700975A

Abstract

The invention relates to a flexible optical waveguide-based attitude sensor and a robot. The attitude sensor comprises an optical waveguide, a rack and a weight; the optical waveguide is arranged on the frame, the weight is slidably arranged on the frame along a preset direction, the weight is connected with the surface of the cladding of the optical waveguide and corresponds to the inner core of the optical waveguide, and the preset direction is perpendicular to the axis of the inner core and parallel to the surface of the cladding. The weight of the attitude sensor can only be arranged on the rack in a sliding manner along a preset direction, so that the optical waveguide can realize the perception of the absolute attitude through the gravity component of the weight, and compared with a gyroscope which realizes the attitude perception by means of angular velocity integration, the attitude sensor perceives the absolute attitude, and the problem of accumulated errors caused by the integration process is avoided; the sliding direction of the weight is perpendicular to the axis of the inner core and parallel to the surface of the cladding, so that the output of the optical waveguide has good linear relation with the sine value of the attitude angle, the optical waveguide has convenience in use, and the detection sensitivity is ensured.

Description

Flexible optical waveguide-based attitude sensor and robot

Technical Field

The invention relates to the technical field of robots, in particular to an attitude sensor based on a flexible optical waveguide and a robot.

Background

The perception of self-posture is an important precondition for human movement in the environment, especially the absolute posture perception with gravity as a reference direction. The pose obtained in space itself is of equal importance for robots (e.g. mobile robots, robotic arms). Currently, a gyroscope technology is often adopted for gesture sensing of a robot, and the gesture is obtained through integration of angular velocity. In such a gesture sensing manner, errors in angular velocity measurement are also accumulated continuously, and eventually, deviation of the gesture may be caused.

Disclosure of Invention

Accordingly, it is necessary to provide a flexible optical waveguide-based attitude sensor and a robot, which solve the problem that the attitude sensing of the robot is biased due to the gyroscope technology.

A flexible optical waveguide based attitude sensor, the attitude sensor comprising: an optical waveguide, a frame and a weight;

the optical waveguide is arranged on the rack, the weight is slidably arranged on the rack along a preset direction, and the weight is further connected with the surface of the cladding of the optical waveguide and corresponds to the inner core of the optical waveguide, wherein the preset direction is perpendicular to the axis of the inner core and parallel to the surface of the cladding.

According to the attitude sensor, the weight can only be arranged on the rack in a sliding manner along the preset direction, so that the optical waveguide can realize the sensing of the absolute attitude through the gravity component of the weight, and compared with a gyroscope which realizes the attitude sensing by means of angular velocity integration, the sensing is the absolute attitude, and the integration process and the accumulated error caused by the integration process are avoided; the sliding direction of the weight is perpendicular to the axis of the inner core and parallel to the surface of the cladding, so that the output of the optical waveguide has good linear relation with the sine value of the attitude angle, the convenience is realized in use, and the detection sensitivity is also ensured; the flexible material is adopted as a sensitive unit (namely the optical waveguide), so that the sensor has larger deformation under the action of a tiny force, which is equivalent to the effect of amplifying the force, so that the attitude sensor has very high sensitivity; the optical waveguide has robustness, and the optical waveguide serving as the sensing unit not only can resist overload load, but also has a certain shock absorption and buffering function, so that the robustness can enhance the usability of the attitude sensor in use.

In one embodiment, the number of the inner cores of the optical waveguide is 1, and the shape of the inner cores of the optical waveguide is linear.

In one embodiment, a sliding rail is arranged on the rack, a sliding block capable of sliding along the preset direction is arranged on the sliding rail, and the sliding block is connected with the weight.

In one embodiment, the attitude sensor further includes a first mount connected between the slider and the weight.

In one embodiment, the attitude sensor further comprises a force transmission member, wherein the force transmission member is connected between the weight and the cladding of the optical waveguide, the force transmission member corresponds to the inner core of the optical waveguide, and the area of the side surface of the force transmission member, which is close to the optical waveguide, is smaller than the area of the side surface of the weight, which is close to the optical waveguide.

In one embodiment, the attitude sensor further includes a second mount connected between the force transmitting member and the weight.

In one embodiment, the housing comprises: the device comprises a base, a mounting seat and a stand column for supporting the mounting seat above the base;

the optical waveguide is arranged on the base, and the weight is slidably arranged on the mounting seat.

In one embodiment, the mounting base is capable of sliding up and down along the upright.

In one embodiment, the upright is a screw, and the frame further comprises a nut in threaded connection with the upright, the nut being used to lock the mount at any height.

A robot comprising a flexible optical waveguide based attitude sensor as claimed in any one of the preceding claims.

According to the robot, the weight of the gesture sensor can only be slidably arranged on the rack along the preset direction, so that the optical waveguide can realize the sensing of the absolute gesture through the gravity component of the weight, compared with a gyroscope which realizes gesture sensing by means of angular velocity integration, the sensing is the absolute gesture, and the integration process and the accumulated error caused by the integration process are avoided; the sliding direction of the weight is perpendicular to the axis of the inner core and parallel to the surface of the cladding, so that the output of the optical waveguide has good linear relation with the sine value of the attitude angle, the convenience is realized in use, and the detection sensitivity is also ensured; the flexible material is adopted as a sensitive unit (namely the optical waveguide), so that the sensor has larger deformation under the action of a tiny force, which is equivalent to the effect of amplifying the force, so that the attitude sensor has very high sensitivity; the optical waveguide has robustness, and the optical waveguide serving as the sensing unit not only can resist overload load, but also has a certain shock absorption and buffering function, so that the robustness can enhance the usability of the attitude sensor in use.

Drawings

FIG. 1 is a schematic diagram of a flexible optical waveguide-based attitude sensor according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of the working principle of a flexible optical waveguide-based attitude sensor according to an embodiment of the present invention;

fig. 3 is a schematic diagram showing a relationship between the optical loss signal intensity and the sine value of the inclined plane included angle of the attitude sensor based on the flexible optical waveguide according to an embodiment of the present invention.

Wherein, the reference numerals in the drawings are as follows:

10. an attitude sensor; 100. an optical waveguide; 200. a frame; 210. a base; 220. a mounting base; 230. a column; 300. a weight; 400. a slide rail; 500. a slide block; 600. a first mounting member; 700. a force transmitting member; 800. a second mounting member; 20. and (5) an inclined plane.

Detailed Description

In order that the above objects, features and advantages of the invention will be readily understood, a more particular description of the invention will be rendered by reference to the appended drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The present invention may be embodied in many other forms than described herein and similarly modified by those skilled in the art without departing from the spirit of the invention, whereby the invention is not limited to the specific embodiments disclosed below.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present invention.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

In the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

In the present invention, unless expressly stated or limited otherwise, a first feature "up" or "down" a second feature may be the first and second features in direct contact, or the first and second features in indirect contact via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.

It will be understood that when an element is referred to as being "fixed" or "disposed" on another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like are used herein for illustrative purposes only and are not meant to be the only embodiment.

In this regard, one embodiment of the present invention provides a flexible optical waveguide-based attitude sensor 10, as shown in fig. 1, the flexible optical waveguide-based attitude sensor 10 comprising: optical waveguide 100, chassis 200, and weight 300; the optical waveguide 100 is disposed on the chassis 200, and the weight 300 is slidably disposed on the chassis 200 in a predetermined direction, wherein the predetermined direction is perpendicular to the axis of the inner core of the optical waveguide 100 and parallel to the surface of the cladding of the optical waveguide 100, and the weight 300 is further connected to the surface of the cladding of the optical waveguide 100 and corresponds to the inner core of the optical waveguide 100.

Regarding the structure of the optical waveguide 100, as one example, the optical waveguide 100 includes: cladding, inner core, and optoelectronic component and circuit; the cladding is used for wrapping the inner core, and the photoelectric element and the circuit, wherein the photoelectric element and the circuit comprise a light emitting diode, a light source power supply circuit, a photoelectric triode and a signal acquisition circuit. The cladding layer and the inner core of the optical waveguide 100 are flexible materials with refractive indexes satisfying total reflection of the optical waveguide, wherein the refractive index of the material of the inner core of the optical waveguide 100 is higher than that of the material of the cladding layer of the optical waveguide 100, for example, the material of the cladding layer of the optical waveguide 100 may be silicone rubber, and the material of the inner core of the optical waveguide 100 may be polyurethane or polyacrylate. In addition, the shape of the core is a straight line shape, and the straight line shape of the core not only facilitates the manufacturing of the core, but also can more easily satisfy the total reflection requirement of the optical waveguide 100.

The principle of operation of the optical waveguide 100 described above may be described as: the light source power supply circuit supplies power to the light emitting diode and converts electric energy into light energy; the original optical signal emitted by the light emitting diode propagates in the inner core, when a force stimulus acts on the inner core, the inner core deforms, so that the original optical signal in the inner core is attenuated and becomes a lossy optical signal, the lossy optical signal is detected by a phototriode arranged at the tail end of the inner core, and the lossy optical signal is converted into an analog electric signal; the signal acquisition circuit captures an analog electric signal sent by the phototriode, and finally sends the analog electric signal to external equipment (such as a wireless receiving module), the external equipment receives, records and analyzes the analog electric signal, and decodes and restores original force stimulation information through operations such as linear interpolation, neural network and the like.

The dimension of the perceived gesture of the optical waveguide 100 is related to the number of inner cores of the optical waveguide 100, for example, if the gesture of the optical waveguide 100 along the defined angular direction (i.e. the preset direction) is sensed for sensing the one-dimensional gesture, and the gesture of the optical waveguide 100 is insensitive to the gesture changes of other two perpendicular directions in the space, at this time, an inner core may be disposed in the optical waveguide 100, and at this time, the weight 300 may be disposed at a position directly above the axis of the inner core, so that when the weight 300 drives the optical waveguide 100 to move, the maximum displacement may be detected by the inner core, thereby improving the sensitivity of the optical waveguide 100; if, in order to realize the perception of the two-dimensional posture, 2 inner cores may be disposed in the optical waveguide 100, and the 2 inner cores are crossed in a cross shape, correspondingly, the weight 300 is disposed at a position directly above the axes of the two inner cores and can slide in two preset directions perpendicular to each other in the plane. Of course, two optical waveguides 100 capable of realizing one-dimensional gesture sensing may be directly placed vertically to realize two-dimensional gesture sensing. The operation principle and structure of the attitude sensor 10 will be described one by taking an example in which an inner core is provided in the optical waveguide 100.

To describe the sensitivity of the attitude sensor 10 to the attitude inclination, referring to fig. 2, the attitude sensor 10 is fixed on the inclined surface 20 having the inclination angle θ. The operating principle of the attitude sensor 10 can be described as: the optical waveguide 100 of the attitude sensor 10 acts as a sensing element that is capable of responding to a changing tangential force acting on its surface (i.e., g×sin θ shown in fig. 2, G being the weight force of the weight 300). While the gravity of the weight 300 will generate a component perpendicular to the surface of the optical waveguide 100 (i.e., g×cos θ shown in fig. 2) and a component parallel to the surface of the optical waveguide 100 (i.e., g×sin θ shown in fig. 2) that varies depending on the posture on the surface of the optical waveguide 100, since the weight 300 is slidably disposed on the housing 200 only in a predetermined direction, the component acting on the surface of the optical waveguide 100 is kept constant while there is no constraint on the portion of the component parallel to the surface of the optical waveguide 100. Then as the attitude sensor 10 increases gradually from the horizontal home position to the attitude angle in the defined angular direction, the component force of the weight 300 parallel to the surface of the optical waveguide 100 increases gradually, and the response of the optical waveguide 100 increases gradually and is linearly related to the magnitude of the force, i.e., in a sinusoidal increasing relationship with the attitude angle (see fig. 3). In fig. 3, "going" means that the inclination angle θ of the inclined surface gradually increases from 0 ° to 90 °, and "returning" means that the inclination angle θ of the inclined surface gradually decreases from 90 ° to 0 °.

The attitude sensor 10 based on the flexible optical waveguide as described above, the weight 300 is slidably disposed on the frame 200 only along the preset direction, which enables the optical waveguide 100 to realize the sensing of the absolute attitude through the gravity component of the weight 300, compared with the gyroscope which realizes the attitude sensing by means of the angular velocity integration, the sensing is the absolute attitude, and there is no integration process and the accumulated error problem caused by the integration process; since the sliding direction of the weight 300 is perpendicular to the axis of the inner core and parallel to the surface of the cladding, the output of the optical waveguide 100 has a good linear relationship with the sine value of the attitude angle, and the convenience is provided in use, and the sensitivity of detection is also ensured; the flexible material is used as the sensitive unit (namely, the optical waveguide 100), and has larger deformation even under the action of a tiny force, which is equivalent to the effect of amplifying the force, so that the attitude sensor 10 has high sensitivity; the optical waveguide 100 has robustness, and the optical waveguide 100 as a sensing unit can not only resist overload load, but also has a certain shock absorption and buffering effect, and the robustness can enhance the usability of the attitude sensor 10 in use.

As shown in fig. 1, in some embodiments of the present invention, a slide rail 400 is provided on the rack 200, and a slider 500 capable of sliding along a predetermined direction is provided on the slide rail 400, and the slider 500 is connected with the weight 300. By the cooperation of the slide rail 400 and the slider 500, it is possible to realize that the weight 300 can only slide in a predetermined direction, and also to simplify the structure of the attitude sensor 10.

Regarding how the slider 500 is fitted with the slide rail 400, as an example, the cross-sectional shape of the slide rail 400 is T-shaped, a T-shaped sliding groove is provided on the slider 500, and the slide rail 400 is inserted into the sliding groove of the slider 500 to slide the slider 500 along itself.

Alternatively, the sliding rail 400 may be disposed on the frame 200 by welding, screwing, fastening, or the like.

Further, in some embodiments of the present invention, as shown in fig. 1, the attitude sensor 10 further includes a first mount 600, the first mount 600 being connected between the slider 500 and the weight 300. The first mount 600 facilitates the connection of the slider 500 to the weight 300.

Alternatively, the first mounting member 600 may be a plastic member that may be manufactured and machined using additive manufacturing. The first mounting member 600 may be mounted on the slider 500 by using a screw, an adhesive, a buckle, or the like, and the first mounting member 600 may be connected to the weight 300 by using an adhesive, a screw, an interference fit, or the like, wherein the weight 300 may be a metal block.

As shown in fig. 1, in some embodiments of the present invention, the attitude sensor 10 further includes a force-transmitting member 700, where the force-transmitting member 700 is connected between the weight 300 and the cladding of the optical waveguide 100, the force-transmitting member 700 corresponds to the inner core of the optical waveguide 100, and the area of the side of the force-transmitting member 700 near the optical waveguide 100 is smaller than the area of the side of the weight 300 near the optical waveguide 100. The side of force-transmitting member 700 that is close to optical waveguide 100 refers to the side of force-transmitting member 700 that is in direct contact with the cladding of optical waveguide 100; if the force transmitting member 700 is not provided between the weight 300 and the cladding of the optical waveguide 100, the side of the weight 300 close to the optical waveguide 100 is in direct contact with the cladding of the optical waveguide 100. The force transmission member 700 having a small size is provided between the weight 300 and the optical waveguide 100, so that the weight of the weight 300 can be concentrated as much as possible on the optical waveguide 100, and the sensitivity of the optical waveguide 100 can be increased.

Regarding the manner of attachment of force-transmitting member 700, as one way, force-transmitting member 700 may be attached to the cladding surface of optical waveguide 100 by means of an adhesive, screw, interference fit, or the like.

Further, in some embodiments of the present invention, as shown in FIG. 1, the attitude sensor 10 further includes a second mount 800, the second mount 800 being connected between the force transmitting member 700 and the weight 300. The second mount 800 facilitates the connection of the force transfer member 700 and the weight 300.

Alternatively, the second mounting member 800 may be a plastic member, may be manufactured using additive manufacturing, and may be coupled to the force-transmitting member 700, the weight 300 using adhesive, screws, interference fit, or the like.

As shown in fig. 1, in some embodiments of the invention, a rack 200 includes: base 210, mount 220, and upright 230 supporting mount 220 above base 210; the optical waveguide 100 is disposed on the base 210 and the weight 300 is slidably disposed on the mount 220. The frame 200 with the structure has a simple structure and is convenient to produce and manufacture. As one example, the slide rail 400 is disposed on the mount 220.

Regarding the number of the columns 230, as an example, 4 columns may be provided, each column 230 being disposed between the base 210 and a corner of the mount 220.

Further, in some embodiments of the present invention, mount 220 is capable of sliding up and down column 230. The initial pre-compression of the optical waveguide 100 by the weight 300 can be controlled by leveling the weight 300 on the surface of the optical waveguide 100 by moving the mount 220 up and down.

Specifically, in some embodiments of the present invention, as shown in fig. 1, the column 230 is a screw, and the frame 200 further includes a nut threadedly coupled with the column 230 for locking the mount 220 at any height. It will be appreciated that the mounting base 220 is provided with a through hole for the upright 230 to pass through. As an example, two nuts are provided on each upright 230, and when the mount 220 reaches a preset height, the mount 220 is clamped by the cooperation of the two nuts and the screw, so that the mount 220 is locked.

Another embodiment of the present invention provides a robot comprising a gesture sensor 10 as described in any of the above.

As an example, the robot may be a mobile robot or a robot arm.

To describe the sensitivity of the attitude sensor 10 of the robot to the attitude inclination, referring to fig. 2, the attitude sensor 10 is fixed on the inclined surface 20 having the inclination angle θ. The operating principle of the attitude sensor 10 can be described as: the optical waveguide 100 of the attitude sensor 10 acts as a sensing element that is capable of responding to a changing tangential force acting on its surface (i.e., g×sin θ shown in fig. 2, G being the weight force of the weight 300). While the gravity of the weight 300 will generate a component perpendicular to the surface of the optical waveguide 100 (i.e., g×cos θ shown in fig. 2) and a component parallel to the surface of the optical waveguide 100 (i.e., g×sin θ shown in fig. 2) that varies depending on the posture on the surface of the optical waveguide 100, since the weight 300 is slidably disposed on the housing 200 only in a predetermined direction, the component acting on the surface of the optical waveguide 100 is kept constant while there is no constraint on the portion of the component parallel to the surface of the optical waveguide 100. Then as the attitude sensor 10 increases gradually from the horizontal home position to the attitude angle in the defined angular direction, the component force of the weight 300 parallel to the surface of the optical waveguide 100 increases gradually, and the response of the optical waveguide 100 increases gradually and is linearly related to the magnitude of the force, i.e., in a sinusoidal increasing relationship with the attitude angle (see fig. 3).

As described above, the weight 300 of the gesture sensor 10 is slidably disposed on the frame 200 only in a preset direction, which allows the optical waveguide 100 to realize sensing of an absolute gesture through a gravity component of the weight 300, which is an absolute gesture sensed by means of a gyroscope performance ratio of gesture sensing by means of angular velocity integration, without an integration process and an accumulated error problem caused by the integration process; since the sliding direction of the weight 300 is perpendicular to the axis of the inner core and parallel to the surface of the cladding, the output of the optical waveguide 100 has a good linear relationship with the sine value of the attitude angle, and the convenience is provided in use, and the sensitivity of detection is also ensured; the flexible material is used as the sensitive unit (namely, the optical waveguide 100), and has larger deformation even under the action of a tiny force, which is equivalent to the effect of amplifying the force, so that the attitude sensor 10 has high sensitivity; the optical waveguide 100 has robustness, and the optical waveguide 100 as a sensing unit can not only resist overload load, but also has a certain shock absorption and buffering effect, and the robustness can enhance the usability of the attitude sensor 10 in use.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The above examples illustrate only a few embodiments of the invention, which are described in detail and are not to be construed as limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.

Claims

1. A flexible optical waveguide based attitude sensor, characterized in that the attitude sensor (10) comprises: an optical waveguide (100), a chassis (200), and a weight (300); the optical waveguide (100) includes: the photoelectric device comprises a cladding, an inner core and a photoelectric element and a circuit, wherein the cladding is used for wrapping the inner core and the photoelectric element and the circuit, and the photoelectric element and the circuit comprise a light emitting diode, a light source power supply circuit, a photoelectric triode and a signal acquisition circuit;

the light source power supply circuit is used for supplying power to the light emitting diode so as to convert electric energy into light energy; the original light signal emitted by the light emitting diode can be transmitted in the inner core, when a force stimulus acts on the inner core, the inner core deforms, so that the original light signal in the inner core is attenuated to become a lossy light signal, and the lossy light signal can be converted into an analog electric signal when being detected by the phototriodes arranged at the tail end of the inner core; the signal acquisition circuit is used for capturing the analog electric signal sent by the phototriode and sending the analog electric signal to external equipment;

the optical waveguide (100) is arranged on the frame (200), the weight (300) is slidably arranged on the frame (200) along a preset direction, the weight (300) is also connected with the surface of the cladding of the optical waveguide (100) and corresponds to the inner core of the optical waveguide (100), and the preset direction is perpendicular to the axis of the inner core of the optical waveguide (100) and parallel to the surface of the cladding of the optical waveguide (100).

2. The attitude sensor according to claim 1, characterized in that the number of cores of the optical waveguide (100) is 1, and the shape of the cores of the optical waveguide (100) is a straight line.

3. The attitude sensor according to claim 1, characterized in that a slide rail (400) is provided on the frame (200), and a slider (500) slidable in the preset direction is provided on the slide rail (400), the slider (500) being connected with the weight (300).

4. A posture sensor according to claim 3, characterized in that the posture sensor (10) further comprises a first mount (600), which first mount (600) is connected between the slider (500) and the weight (300).

5. The attitude sensor according to claim 1, characterized in that the attitude sensor (10) further comprises a force transmitting member (700), the force transmitting member (700) being connected between the weight (300) and the cladding of the optical waveguide (100), the force transmitting member (700) corresponding to the inner core of the optical waveguide (100), a side area of the force transmitting member (700) close to the optical waveguide (100) being smaller than a side area of the weight (300) close to the optical waveguide (100).

6. The attitude sensor according to claim 5, wherein the attitude sensor (10) further comprises a second mounting (800), the second mounting (800) being connected between the force transmitting member (700) and the weight (300).

7. The attitude sensor according to any one of claims 1 to 6, wherein the rack (200) includes: a base (210), a mount (220), and a column (230) supporting the mount (220) above the base (210);

the optical waveguide (100) is disposed on the base (210), and the weight (300) is slidably disposed on the mount (220).

8. The attitude sensor according to claim 7, characterized in that the mount (220) is slidable up and down along the upright (230).

9. The attitude sensor according to claim 8, wherein the upright (230) is a screw, the frame (200) further comprising a nut in threaded connection with the upright (230), the nut being used to lock the mount (220) at any height.

10. A robot, characterized in that it comprises a flexible optical waveguide based attitude sensor (10) according to any one of claims 1-9.