Modular sensor-actuator

Abstract

The present application relates to a sensor-actuator (10) comprising at least two modules (12, 14) comprising: • - a core (18) designed to expand and generate forces under the effect of an environmental stimulus such as heat or humidity, • - a fibrous network (20) surrounding the core (18) so as to constrain the expansion of the core (18) in order to favour a deformation along at least one axis of extension, bending or torsion, the sensor-actuator (10) being such that, among the two modules (12, 14), • - the first end (30) of the core (18) of the first module (12) comprises a female assembly portion (34), and • - the second end (32) of the core (18) of the second module (14) comprises a male assembly portion (36) able to cooperate with the female assembly portion (34) of the first module (12) in order to assemble the first module (12) to the second module (14).

Description

[0001] DESCRIPTION

[0002] TITLE: Modular sensor-actuator

[0003] Technical field of the invention

[0004] The present invention relates to the field of sensors and actuators in the context of frugal robotics which are capable of sensing environmental changes and reacting to them by deforming or providing forces.

[0005] The invention relates more particularly to an assemblable and modular sensor-actuator as well as a method of manufacturing such a sensor-actuator.

[0006] Technical background

[0007] In the field of frugal robotics, sensor-actuators that use environmental stimuli as an energy source are known.

[0008] Examples of sensor-actuators are for example described in documents US2012161579A1, FR1523873, US2021265924A1 or US2014041377.

[0009] Stimuli can be, for example, a change in ambient temperature or humidity.

[0010] Conventionally, such sensor-actuators are designed to deform in response to a variation in temperature or humidity of the medium in which the sensor-actuator is located.

[0011] These sensor-actuators are designed to enable specific movements, which can be carried out in certain directions or articulated around certain axes. Thus, for each need, a new sensor-actuator must be developed.

[0012] However, there is an interest in having a sensor-actuator that can be adapted to any type of movement and effort.

[0013] Summary of the invention

[0014] The invention proposes a sensor-actuator comprising at least two modules, including a first and a second module, each module comprising:

[0015] - a core extending in a main direction of elongation between a first end and a second end and being designed to expand and generate forces under the effect of an environmental stimulus such as heat or humidity,

[0016] - a fibrous network enveloping the core so as to constrain the expansion of the core to favor a deformation along at least one axis of extension, flexion or torsion, the actuator being such that among the two modules,

[0017] - the first end of the core of the first module comprises a female assembly portion, and

[0018] - the second end of the core of the second module comprises a male assembly portion capable of cooperating with the female assembly portion of the first module to assemble the first module to the second module.

[0019] According to other characteristics of the invention:

[0020] - the core comprises a cylindrical main body;

[0021] - the core comprises a tubular main body;

[0022] - the core is made of polymer;

[0023] - the core is made of metal;

[0024] - the fibrous network is made of composite material comprising mineral fibers such as carbon or basalt fibers and a polymer matrix providing a binder;

[0025] - the fibers form a helical winding along the core according to the main direction of elongation;

[0026] - the inclination of the fibers relative to the main direction of elongation and the spacing between the fibers of a module are configured to obtain a predetermined deformation by torsion around the main axis of elongation;

[0027] - the core of a module has a length, a diameter and a wall thickness configured to obtain a predetermined deformation by torsion around the main axis of elongation;

[0028] - the core of a module comprises a lateral notch configured to obtain a deformation by bending around an axis perpendicular to the main axis of elongation; - the actuator sensor comprises a mechanism for locking the assembly of the modules.

[0029] The invention also relates to a solar tracker comprising a sensor-actuator according to the invention, the core of a module being capable of expanding under the effect of solar heat.

[0030] The invention also relates to a method for producing an actuator module, characterized in that it comprises the following steps:

[0031] - E1: production by additive manufacturing or by extrusion of a polymer core extending in a main direction of elongation between a first end and a second end,

[0032] - E2: production, at the first end of the core, of a female assembly portion,

[0033] - E3: production, at the second end of the core, of a male assembly portion capable of cooperating with the female assembly portion of another module to assemble the module being produced with the other module;

[0034] - E4: winding of carbon, basalt or plant fibers soaked in polymer so as to envelop the core of a helical fibrous network extending in a main direction of elongation.

[0035] The invention also relates to a method of manufacturing an actuator characterized in that it comprises the following steps:

[0036] - E5: production of at least two modules according to the process described previously, and

[0037] - E6: assembly of modules involving the insertion of a male assembly portion of one module into a female assembly portion of another module.

[0038] Brief description of the figures

[0039] Other characteristics and advantages of the invention will appear during the reading of the detailed description which follows for the understanding of which reference will be made to the appended drawings in which: [Fig.1] is a schematic perspective view of a sensor-actuator before assembly according to an embodiment of the invention;

[0040] [Fig.2] is a schematic perspective view of the sensor-actuator of Figure 1 after assembly;

[0041] [Fig.3] is a schematic perspective view of a sensor-actuator module of Figure 1;

[0042] [Fig.4] is a schematic bottom view of the module of Figure 3;

[0043] [Fig.5] is a schematic perspective view of another module of the sensor-actuator of Fig. 1 having a different form and function than the module of Fig. 3;

[0044] [Fig.6] is a perspective view showing four main module core bodies wrapped with a fibrous network forming a helical winding with different winding angles;

[0045] [Fig.7] is a perspective view showing four main core bodies with different rates of core coverage by the fiber network;

[0046] [Fig.8] is a bottom view showing four main core bodies with different core wall thicknesses;

[0047] [Fig.9] is a perspective view showing four main core bodies with different lengths;

[0048] [Fig.10] is a partial perspective view of a solar tracker according to one embodiment of the invention;

[0049] [Fig.11] is a flowchart of a method for producing a sensor-actuator module according to the invention;

[0050] [Fig.12] is a schematic perspective view of a rotating 3D (three-dimensional) printer winding the fibers of the fiber network onto the core of a module.

[0051] Detailed description of the invention

[0052] For the description of the invention and the understanding of the claims, the vertical, longitudinal and transverse orientations according to the reference V, L, T indicated in the figures, the longitudinal L and transverse T axes of which extend in a horizontal plane, will be adopted, without limitation and without limiting reference to Earth's gravity. By convention, the vertical axis is oriented from bottom to top, the longitudinal L axis is oriented from back to front and the transverse axis is oriented from right to left.

[0053] In the following description, identical, similar or analogous elements will be designated by the same reference numbers.

[0054] Figures 1 and 2 illustrate a sensor-actuator 10 according to a first embodiment of the invention.

[0055] In the example shown, the sensor-actuator 10 comprises three modules including a first module 12, a second module 14 and a third module 16. In Figure 1, the three modules 12 to 16 are disconnected and are therefore well separated from each other. In Figure 2, the three modules 12 to 16 are assembled, that is to say nested inside each other. The sensor-actuator may comprise a mechanism for locking the assembly of the modules such as a lug engaged against a stop by rotation or even a weld fixing the two modules together.

[0056] Figure 3 shows one of the modules, for example, the first module 12 or the second module 14.

[0057] The module 12, 14 comprises a central core 18 which gives its structure to the module 12, 14 and a peripheral fibrous network 20 applied to the core 18.

[0058] The core 18 extends along a main direction of vertical elongation D. In the example, the core 18 has a generally cylindrical shape and D constitutes the central axis of symmetry of revolution of the core 18.

[0059] Nucleus 18 has a strong ability to expand in response to environmental stimuli. The ability to expand is measured by a coefficient of expansion.

[0060] The expansion coefficient measures the relative increase in volume when only one parameter corresponding to the stimulus is varied.

[0061] Depending on the intended application for the sensor-actuator, the stimulus can be, for example:

[0062] - heat and in this case the core has a high coefficient of thermal expansion, - humidity and in this case the core has a high hygroscopic expansion.

[0063] Thermal expansion is the tendency of matter to change volume in response to changes in temperature. When a substance is heated, its particles move more, thus maintaining a greater average separation. Thermal expansion results in an increase in the volume of a body.

[0064] For purely illustrative purposes and in no way limiting, the core may have a coefficient of thermal expansion greater than 10' 6 K' 1 The materials selected to make a core capable of expanding with heat are, for example, polymers or metals.

[0065] Temperature can be induced directly by a variation in environmental conditions or indirectly by the Joule effect when the material is conductive.

[0066] Water expansion is the change in volume of matter due to the absorption of water when the humidity in the surrounding atmosphere changes. A difference in water concentration in a material can cause a change in the volume of the material through a difference in density.

[0067] This capacity for hydric or hygroscopic expansion of a material can be measured by characterizing the hygroscopic expansion as a function of the evolution of the water content of the material, by measuring the water absorption isotherm which corresponds to a curve, representing for a given temperature. The curves of the materials of interest for producing the sensor-actuator have a relatively steep slope.

[0068] Ambient humidity, or hygrometric degree, corresponds to the ratio of the partial pressure of water vapor contained in the air to the saturated vapor pressure at the same temperature. It is therefore a measure of the ratio between the water vapor content of the air and its maximum capacity to contain it under these conditions. This ratio depends not only on temperature but also on pressure. Highly hygroscopic materials selected to create a core capable of expanding with humidity are, for example, synthetic polymers.

[0069] Core 18 can also be made of composite material.

[0070] The core 18 may be, for example, a tube or a mandrel.

[0071] The fibrous network 20 is produced by means of fibers 22 wound around the core 18 so as to envelop the core 18. In the example shown, the fibrous network 20 is wound on a peripheral lateral face 24 delimiting the circumference of the core. Thus, the fibrous network 20 restricts the radial expansion of the core 18. The expansion of the core 18 will therefore occur mainly along the axis D with regard to the extension.

[0072] Furthermore, since the fibers 22 are wound in a D-axis helical winding, expansion of the core 18 will also cause a twisting motion about the D-axis as shown by arrow 26.

[0073] Thus, the fibrous network 20 is arranged so as to constrain the expansion of the core 18 to favor a deformation along at least one axis of extension, flexion or torsion.

[0074] The fibrous network 20 can be made of a composite material comprising mineral fibers 22 such as carbon or basalt fibers and a polymer matrix providing a binder between the fibers 22 and the core 18.

[0075] In particular, the fibers 22 can be structured based on the microstructure of bast plant fibers having a concentric bimetallic shape.

[0076] The core 18 comprises a main body 28 having a first lower end 30 and a second upper end 32.

[0077] The first end 30 comprises a female assembly portion 34. The second end 32 comprises a male assembly portion 36.

[0078] In the example shown, the male assembly portion 36 of a module 12, 14, 16 is capable of cooperating with the female assembly portion 34 of any other module to assemble the two modules in question. Alternatively, a module:

[0079] - could comprise a female assembly portion 34 capable of cooperating specifically with the male assembly portion 36 of another module placed immediately below, and / or

[0080] - could comprise a male assembly portion 36 capable of cooperating specifically with the female assembly portion 34 of yet another module, placed immediately above.

[0081] In the example shown, the male assembly portion 36 is a stud 38 projecting from an upper face 40 of the main body 28 of the core 18, the upper face 40 being located at the second end 32 of the main body 28. The stud 38 of the male assembly portion 36 has a cylindrical shape of axis D. The stud 38 may be solid or hollow and be open or closed in the lower part and / or in the upper part. By way of illustration and in no way limiting, the stud 38 may have a diameter substantially equal to two-thirds of the diameter of the main body 28 of the core 18. Also by way of illustration and in no way limiting, the stud 38 may have a height substantially equal to half the radius of the stud 38.

[0082] The female assembly portion 34 is shown in Figure 4. The female assembly portion 34 is formed in a lower face 42 of the main body 28 of the core 18. The lower face 42 comprises an orifice 44 delimited by side walls 46. The side walls 46 of the orifice 44 are part of the female assembly portion 34. The side walls 46 are intended to be in contact with a peripheral wall 47 of a stud 38 of a male assembly portion 36 of another module. To prevent the relative sliding of two assembled modules, the orifice 44 is sized so that the side walls 46 delimiting it rub against the peripheral wall 47 of the corresponding stud 38.

[0083] The fibrous network 20 has been shown with a deliberately exaggerated thickness for the sake of clarity. The example in Figure 4 corresponds to the particular case of a tubular main body 28 with the same internal diameter as the orifice 44. In Figure 4, it is visible that the wall of the core 18 has a thickness e n and that the fibrous network 20 has a thickness £ m . The sizing of the core thicknesses En and £ m of fiber network conditions the magnitude of the deformation in response to a given stimulus as will be shown in the context of Figure 8.

[0084] Figure 5 shows a module of the sensor-actuator 10, for example the module 16, having a shape different from that of the modules of Figure 3.

[0085] The module 16 of Figure 5 differs from the module 12, 14 of Figure 3 in that it comprises at least one notch 48 in the peripheral lateral face 24.

[0086] In the example shown in Figure 5, the notch 48 corresponds to a notch extending horizontally along the entire circumference of the core 18 at mid-height between the first end 30 and the second end 32. By way of illustration and in no way limiting, the notch has a depth substantially equal to half the radius of the core 18.

[0087] The notch 48 is made between two bimetal ligaments having deformations in phase to generate a movement in the same direction. Alternatively, the notch 48 can be made between a ligament generating the movement and another neutral ligament not generating any particular movement.

[0088] The notch 48 allows a bending movement around a horizontal axis A located in the plane of the notch 48 and allows the forces to be oriented in a specific manner. This bending movement is represented by the arrow 50 and corresponds to a situation in which the stimulus comes from the right of the figure and is oriented in the transverse direction T. This configuration is particularly suitable in the case of a spatial application in which the stimulus is not global insofar as the convection phenomenon does not intervene.

[0089] As shown in Figure 5, the module 16 may be hollow.

[0090] The distribution of the fibers 22 is adjusted to obtain the desired deformations and forces.

[0091] Figures 6 to 9 show different configurations of main bodies 28 of core 18 wrapped with a fibrous network 20. In each figure, four examples of main bodies 28 of core 18 wrapped with a fibrous network 20 are given and only one parameter varies in the design of these four examples. Varying this parameter makes it possible to obtain a different deformation of the module in response to a given stimulus.

[0092] Figure 6 shows main bodies 28 of core 18 wrapped with a fibrous network 20 forming a helical winding along the core along the main elongation direction D with an angle a relative to the direction D varying between 10° (left example) and 60° (right example). Table 1 below indicates experimental measurements of twist rate with temperature (dtorsion / dT) and percentage elongation (AL / L) for each angle a.

[0093] [Table 1]

[0094] The measurements in Table 1 show that the twist rate dtorsion / dT is more than twice as low for an angle of 10° as for angles of 35° to 60°, for which the twist rate is approximately equivalent. On the other hand, the higher the angle a among the wrap angles studied, the lower the elongation. In particular, the elongation is approximately half as high for an angle a of 60° as for an angle a of 10°. Thus, an angle a of 35% appears to be the best compromise tested because it allows both a large twist angle and a large elongation to be obtained.

[0095] Figure 7 shows main bodies 28 of core 18 wrapped with a fibrous network 20 forming a helical winding along the core along the main elongation direction D with a constant angle a of 35° and with a rate of coverage of the core 18 by the fibrous network 20 varying between 10° (example on the left) and 60° (example on the right) of the peripheral lateral face 24. Table 2 below indicates experimental measurements of twist rate with temperature (dtorsion / dT) and percentage elongation (AL / L) for each rate of coverage of the core 18 by the fibrous network 20.

[0096] [Table 2]

[0097] The measurements in Table 2 show that the torsion rate dtorsion / dT is approximately three times lower for a coverage rate of the core 18 by the fibrous network 20 of 10% than for coverage rates of 35% to 60% for which the torsion rate is approximately equivalent. As for the elongation, it is more than twice as high for a coverage rate of 10% as for coverage rates of 35% to 60% for which the elongation is approximately equivalent. Thus, to obtain a high torsion angle, coverage rates greater than or equal to 35% must be favored and to obtain a high elongation, coverage rates less than 35% must be favored.

[0098] Figure 8 shows main bodies 28 of core 18 wrapped with a fibrous network 20 forming a helical winding along the core along the main direction of elongation D with a constant angle a of 35°, with a coverage rate of the core 18 by the fibrous network 20 constant of 35%, and with a thickness e n of the core wall 18 varying so that the ratio of the thickness e m of the fibrous network 20 on the thickness e n of the core wall 18 varies between 100% (left example) and 6% (right example). Table 3 below shows experimental measurements of twist rate with temperature (dtorsion / dT) and percentage elongation (AL / L) for each ratio £ m / £n.

[0099] [Table 3]

[0100] The measurements in Table 3 show that the torsion rate dtorsion / dT is slightly lower for a ratio £ m / £n of 6% and slightly higher for a £ ratiom / £n of 100% compared to the torsion rates dtorsion / dT for ratios of 25% and 75%. On the other hand, the elongation is slightly lower for £m / £n ratios of 6% and 100% than for ratios £ m / £n of 25% and 75%. During these tests on the thickness £ n of the core wall 18, the torque generated during deformation with heat was measured. For a ratio £ m / £n of 6%, the torque remained below 10 Nmkg -1 whatever the temperature while for ratios £ m / £n from 25% to 100%, the torque was greater than 20 Nmkg' 1 at 100°C, therefore twice as high. For ratios £ m / £n between 25% and 75%, the twist angle and elongation are little impacted by the thickness £ n of the core wall 18 and the torque obtained is satisfactory.

[0101] Figure 9 shows main bodies 28 of core 18 wrapped in a fibrous network 20 forming a helical winding along the core along the main direction of elongation D with:

[0102] - a constant angle a of 35°,

[0103] - a constant rate of coverage of the core 18 by the fibrous network 20 of 35%,

[0104] - a thickness £ n of the core wall 18 constant with a ratio £ m / £n of 50%,

[0105] - a constant diameter B of the main body 28 of 2cm, and

[0106] - a length C of the main body 28 along the direction D varying so that the ratio C / B of the length to the diameter of the main body 28 varies between 7 (example on the right) and 1.5 (example on the left). Table 4 below indicates experimental measurements of torsion rate with temperature (dtorsion / dT) and percentage elongation (AL / L) for each C / B ratio.

[0107] [Table 4]

[0108] The measurements in Table 4 show that the torsion rate dtorsion / dT increases with the ratio C / B and therefore with the length C of the main body 28. As for the percentage of elongation (AL / L), it remains of the same order of magnitude between 10% and 16%. The torsion angle and the elongation therefore increase with the length C of the main body 28 of the core 18.

[0109] The examples in Figures 6 to 9 show that it is possible to configure a module to obtain a predetermined deformation, in particular through experimental measurements. The predetermined deformations are, for example, a torsion rate with temperature (dtorsion / dT) and a percentage of elongation (AL / L). The parameters used to configure the module are:

[0110] - the angle a of inclination of the fibers relative to the main direction of elongation,

[0111] - the rate of coverage of the core 18 by the fiber network 20 or the spacing between the fibers of a module, - the length C of the main body 28 of the core,

[0112] - the diameter B of the core 18 orthogonal to the main direction of elongation D, and / or

[0113] - the wall thickness of the core 18 or the thickness £ m of the fiber network.

[0114] More generally, the deformation of a module is programmable by the architecture and the choice of materials used.

[0115] Figure 10 shows an example of assembly of modules 12, 14, 16 forming a sensor-actuator 10 for example to produce a solar tracker. The modules 12, 14, 16 are assembled in series, that is to say they are fitted together in the vertical elongation direction D by means of the male 36 and female 34 assembly portions.

[0116] In the case of an assembly of modules 12, 14, 16 in series, the deformations obtained in response to a stimulus can be modeled in order to be predictable.

[0117] Such an assembly can, for example, make it possible to obtain a solar tracker or solar follower. A solar tracker is a device that allows a heliographic telescope to observe the sun or some of its effects in the atmosphere, or a solar energy production facility to track the sun according to the heliostat principle. This supporting structure includes one or more sensor-actuators that orient the telescope or the solar panels to increase their efficiency or productivity.

[0118] The solar tracker aims to orient the telescope or panels towards the Sun in real time, to place them in an optimal position in relation to the incidence of solar radiation, i.e. perpendicular to the radiation if possible. Indeed, at any given moment, the position of the sun depends on the time, latitude and day of the year. Real-time adaptation makes it possible to substantially increase the efficiency of the telescope and panels.

[0119] Orientation can be done on two axes:

[0120] - in azimuth, that is to say from east to west, as the day progresses, and

[0121] - in height, that is to say according to the season and the progress of the day. Thanks to an appropriate combination of the modules 12, 14 and 16, it is possible to obtain a solar tracker 54 in the form of a foot placed stably on the ground or fixed to the ground at its base 56. The upper end 58 is fixedly fixed to the telescope or to the solar panels 60. The sensor-actuator 10 is integrated into the foot of the solar tracker 54 and constitutes, for example, its structure. The deformation of the sensor-actuator 10 under the effect of the heat of the sun makes it possible to automatically orient the telescope or the solar panels 60 along two axes. Such a solar tracker 54 does not require any energy input other than that of the sun and / or humidity variation, and in particular does not require additional sensors and control chain. It can be used for space installations in the case where the operation is based on temperature stimulation.

[0122] The invention also relates to a method for producing a sensor-actuator module. The flowchart of such a method is shown in Figure 11. The method for producing an actuator module comprises the following steps:

[0123] - E1: production of a core extending in a main direction of elongation between a first end and a second end in polymer by additive manufacturing or by extrusion,

[0124] - E2: production, at the first end of the core, of a female assembly portion,

[0125] - E3: production, at the second end of the core, of a male assembly portion capable of cooperating with the female assembly portion of another module to assemble the module being produced with the other module;

[0126] - E4: winding of carbon, basalt or plant fibers soaked in polymer so as to envelop the core of a helical fibrous network extending in a main direction of elongation.

[0127] Step E1 can be carried out using a 3D printer that deposits successive layers of the core. Alternatively, step E1 can be carried out by extrusion and the polymer material is then fluidized and pushed through a die to give it its cylindrical or tubular shape. Step E2 can be carried out during additive manufacturing or during extrusion when the female assembly portion is directly derived from the shape of the first end of the core. Alternatively, it can be carried out by machining or by adding an end piece comprising the female assembly portion. The end piece comprising the female assembly portion can be fitted or glued.

[0128] Similarly, step E3 can be carried out during additive manufacturing or during extrusion when the male assembly portion is directly derived from the shape of the first end of the core. Alternatively, it can be carried out by machining or by adding an end piece comprising the male assembly portion. The end piece comprising the male assembly portion can be fitted or glued.

[0129] Figure 12 represents step E4 of winding the fibers onto the core 18. This step E4 can be carried out using a machine 62 such as a rotary printer or a three-dimensional (3D) printer comprising:

[0130] - a rotation axis 64 on which the core 18 is securely fixed, and

[0131] - a head 66 capable of depositing fibers 22 from the fiber network 20 by means of a tip 68. The head 66 is movable in translation along a translation axis 70 parallel to the rotation axis 64 and located immediately above.

[0132] To wind the fibers 22, the rotation axis 64 drives the core 18 in rotation and the head 66 is driven in translation along the translation axis 70 while the fibers are deposited on the peripheral lateral face 24 of the core 18.

[0133] The invention also relates to a method of manufacturing an actuator comprising the following steps:

[0134] - E5: production of at least two modules according to the method for producing a module of an actuator comprising steps E1 to E4, and

[0135] - E6: assembly of the modules comprising the insertion of a male assembly portion of one module into a female assembly portion of another module to produce a series connection of the modules. Step E6 is for example carried out by means of an assembly comparable to that of assembly sets comprising interlocking bricks.

[0136] The assembly of the modules can also include a locking step to prevent the modules from becoming detached. The locking solutions have been described previously.

[0137] The manufacturing of the actuator may also include steps for paralleling the modules as in the example in Figure 10.

[0138] The invention has several technical advantages presented below.

[0139] The invention allows the production of transportable and modular structures according to each specification, in particular thanks to the modular nature conferred by the possibility of assembling modules designed to obtain a specific unitary deformation. The modular actuator of the invention makes it possible to obtain a complex movement by decomposing this complex movement into a plurality of unitary deformations carried out by each module.

[0140] The invention also makes it possible to obtain actuators comprising easily recyclable components.

[0141] The actuator of the invention is particularly robust and reliable since no electronics are required for its operation. The causes of breakdowns are therefore extremely reduced.

[0142] The invention also allows for easy maintenance of the actuator thanks to a particularly simple structure. In the case of a defective module, it is very easy to remove the defective module and replace it with a functional module thanks to the snap-in assembly mechanism.

[0143] Furthermore, the invention provides an actuator which can be used in extreme conditions and in particular in space, notably thanks to its autonomous nature.

[0144] The invention is particularly suitable for the design of autonomous solar trackers. The invention can nevertheless be used for the manufacture of any adaptive system, that is to say any system traditionally composed of sensors and actuators making it possible to adapt the configuration of the system to an environmental stimulus. The invention is applicable in particular in the case of adaptive systems having to perform a rotation with associated forces.

[0145] Legend

[0146] 10 actuator

[0147] 12 first module

[0148] 14 second module

[0149] 16 third module

[0150] 18 core

[0151] 20 fiber network

[0152] 22 fiber

[0153] 24 peripheral side face

[0154] 26 twisting movement

[0155] 28 main body

[0156] 30 first end

[0157] 32 second end

[0158] 34 female assembly portion

[0159] 36 male assembly portion

[0160] 38 plot

[0161] 40 upper face

[0162] 42 lower face

[0163] 44 hole

[0164] 46 side walls

[0165] 47 peripheral wall

[0166] 48 notch

[0167] 54 solar tracker

[0168] 56 base

[0169] 58 upper end

[0170] 60 solar panel or telescope

[0171] 62 machine 64 rotation axis

[0172] 66 head

[0173] 68 tip

[0174] 70 translation axis of the head D main direction of elongation a angle of inclination of the fibers En thickness of the core wall Em thickness of the fiber network B diameter of the main body C length of the main body

Claims

CLAIMS 1. Sensor-actuator (10) comprising at least two modules (12, 14) including a first (12) and a second (14) module, each module comprising: - a core (18) extending in a main direction of elongation (D) between a first end (30) and a second end (32) and being designed to expand and generate forces under the effect of an environmental stimulus including heat or humidity, - a fibrous network (20) enveloping the core (18) so as to constrain the expansion of the core (18) to favor a deformation along at least one axis of extension, flexion or torsion, the sensor-actuator (10) being characterized in that among the two modules (12, 14), - the first end (30) of the core (18) of the first module (12) comprises a female assembly portion (34), and - the second end (32) of the core (18) of the second module (14) comprises a male assembly portion (36) capable of cooperating with the female assembly portion (34) of the first module (12) to assemble the first module (12) to the second module (14), and the core (18) of a module (12, 14, 16) comprising a lateral notch (48) configured to obtain deformation by bending around an axis perpendicular to the main axis of elongation (D).

2. Sensor-actuator (10) according to claim 1, characterized in that the core (18) comprises a cylindrical main body (28).

3. Sensor-actuator (10) according to any one of the preceding claims, characterized in that the core (18) comprises a tubular main body (28).

4. Sensor-actuator (10) according to any one of claims 1 to 3, characterized in that the core (18) is made of polymer.

5. Sensor-actuator (10) according to any one of claims 1 to 3, characterized in that the core (18) is made of metal.

6. Sensor-actuator according to any one of claims 1 to 5, characterized in that the fibrous network (20) is made of composite material comprising mineral fibers (22) such as carbon or basalt fibers and a polymer matrix forming a binder.

7. Sensor-actuator (10) according to the preceding claim, characterized in that the fibers (22) form a helical winding along the core (18) in the main direction of elongation (D).

8. Sensor-actuator (10) according to the preceding claim, characterized in that the inclination of the fibers (22) relative to the main direction of elongation (D) and the spacing between the fibers (22) of a module (12, 14, 16) are configured to obtain a predetermined deformation by torsion around the main axis of elongation (D).

9. Sensor-actuator (10) according to any one of the preceding claims when it depends on claim 3, characterized in that the core (18) of a module (12, 14, 18) has a length (C), a diameter (B) and a wall thickness (EN) configured to obtain a predetermined deformation by torsion around the main axis of elongation (D).

10. Sensor-actuator (10) according to any one of the preceding claims, characterized in that it comprises a mechanism for locking the assembly of the modules (12, 14, 16).

11. Solar tracker (54) characterized in that it comprises a sensor-actuator (10) according to any one of claims 1 to 10, the core (18) of a module (12, 14, 16) being capable of expanding under the effect of solar heat.

12. Method for producing a sensor-actuator module (10) according to any one of claims 1 to 10, characterized in that it comprises the following steps: - E1: production by additive manufacturing or by extrusion of a polymer core (18) extending in a main direction of elongation (D) between a first end (30) and a second end (32), - E2: production, at the first end (30) of the core (18), of a female assembly portion (34), - E3: production, at the second end (32) of the core (18), of a male assembly portion (36) capable of cooperating with the female assembly portion (34) of another module to assemble the module being produced with the other module; - E4: winding of carbon, basalt or plant fibers (22) soaked in polymer so as to envelop the core (18) of a helical fibrous network (20) extending in a main direction of elongation (D).

13. Method for manufacturing a sensor-actuator (10) characterized in that it comprises the following steps: - E5: production of at least two modules (12, 14, 16) according to the method of claim 12, and - E6: assembly of the modules (12, 14, 16) comprising the insertion of a male assembly portion (36) of one module into a female assembly portion (34) of another module.

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