Electrostatic actuator

Abstract

The invention relates to an electrostatic actuator (10) comprising a stator element (12) with multiple stator electrodes (121) embedded in a stator electrode carrier array (125), an actuator element (14) movable relative to the stator element (12) and having multiple actuator electrodes (141) embedded in an actuator electrode carrier array (145), wherein the actuator element (14) is movable by an electrostatic force acting between the stator electrodes (121) and the actuator electrodes (141), wherein a dielectric fluid (16) is disposed in a space (18) between the stator element (12) and the actuator element (14), and an insulating housing (20) surrounding the stator element (12) and the actuator element (14), wherein both the carrier arrays (125, 145) and the insulating housing (20) are designed to be flexible.The actuator according to the invention (10) is relatively flexible and achieves particularly high actuation forces. The invention also relates to a device (100) for generating or maintaining relative motion between two body parts (42, 44) connected to each other by an articulated structure (40).

Description

[0001] The invention relates to a device for generating or supporting relative movement between two body parts connected via a joint-like structure, comprising a first load-bearing structure attached to a first body part and a second load-bearing structure attached to a second body part, which is pivotable relative to the first body part. Such devices are also referred to as exoskeletons or, if they are flexible, as exosuits. An exosuit is thus a type of suit that can be worn by a person to mechanically support their muscle power. Electromechanical actuators are typically used to generate the force necessary to support the person, with the exosuit transmitting the force provided by the actuators between at least two body parts.

[0002] US Patent 9,950,422 B2 discloses such an exosuit. The relative movement of the structure connecting the body parts is generated by flexible linear actuators, so-called twisted-string actuators (TSAs). The TSAs comprise several parallel flexible cable strands which, through twisting together and the resulting shortening, generate an essentially linear tensile force between two points. While the TSAs exhibit some flexibility in the relaxed, untwisted / lightly twisted state due to the flexible cable strands, in the highly twisted state there is a relatively high tensile stress in the individual cable strands, causing their flexibility to decrease significantly with increasing twisting. Furthermore, such actuators are relatively heavy and mechanically complex. In addition, the twisting of flexible cable strands only allows for unidirectional force generation, i.e.,The generation of a tensile force between two points.

[0003] Furthermore, electrostatic actuators are known. An electrostatic actuator comprises a stator element with several stator electrodes embedded in a stator electrode support matrix, an actuator element movable relative to the stator element with several actuator electrodes embedded in an actuator electrode support matrix, wherein the actuator element is movable by an electrostatic force acting between the stator electrodes and the actuator electrodes, wherein a dielectric fluid is arranged in a gap between the stator element and the actuator element, and an insulator housing that encloses the stator element and the actuator element.

[0004] Such electrostatic actuators are known from the prior art. US 2015 / 0134109, for example, discloses an electrostatic actuator comprising a rigid stator element and a rigid actuator element, wherein a gap arranged between the stator and actuator elements is filled with a dielectric fluid. Ideally, the dielectric fluid has a relatively high relative permittivity, which increases the strength of the electric field between the stator and actuator electrodes compared to an actuator with a simple air gap. Consequently, the electrostatic force acting between the stator and actuator electrodes increases compared to an actuator with a pure air gap. As a result, the actuating force generated by the actuator can be significantly increased compared to a conventional air-gap electrostatic actuator.

[0005] US patent 2011 / 0121691 A1 discloses a similar electrostatic actuator, wherein the stator element and the actuator element can be designed flexibly, so that the electrostatic actuator as a whole is deformable.

[0006] US 2007 / 0257582 A1 also reveals a flexible electrostatic actuator.

[0007] The invention is therefore based on the objective of creating a powerful and efficient device for generating or supporting a relative movement between two body parts connected to each other via a joint-like structure.

[0008] This problem is solved by a device for generating or supporting a relative movement between two body parts connected to each other via a joint-like structure, having the features of claim 1.

[0009] The device according to the invention for generating or supporting relative movement between two body parts connected to each other via a joint-like structure comprises a first load-bearing structure attached to a first body part. The device further comprises a second load-bearing structure attached to a second body part, wherein the second body part is pivotable relative to the first body part. The load-bearing structures can be rigid, but are preferably at least partially made of flexible and / or soft materials, such as straps or belts. Such a device is generally referred to as an exosuit or is at least part of an exosuit.The joint-like structure is preferably a joint in the human body, such as a hip or elbow joint, but can also be formed by the spine, which allows, for example, the head to move relative to the torso or the torso relative to the hips. Accordingly, the term "body parts" encompasses not only the extremities, but also the rib cage, head, and buttocks, as well as feet, toes, hands, and fingers.

[0010] The device according to the invention further comprises an electrostatic actuator. The electrostatic actuator comprises a stator element with several stator electrodes embedded in a stator electrode support matrix. The electrostatic actuator further comprises an actuator element movable relative to the stator element, with several actuator electrodes embedded in an actuator electrode support matrix. Consequently, the electrodes in the respective support matrices are completely enclosed by the support matrix material, and the electrodes must have individual connection elements that protrude from the support matrix material.

[0011] The stator electrodes are subjected to a multiphase alternating voltage, inducing a wave-like propagating potential in the stator element. Simultaneously, the actuator electrodes are subjected to a multiphase alternating voltage, inducing another wave-like propagating potential in the actuator element, which is phase-shifted from the wave-like potential of the stator element. The electrostatic interaction between the wave-like potentials of the stator and actuator elements generates an electrostatic force that acts between the stator and actuator electrodes, thereby setting the actuator element in motion.

[0012] The stator and actuator elements are spaced apart, creating a gap between them in which a dielectric fluid is located. It has been shown that the electrostatic force acting between the stator and actuator elements depends significantly on the voltage across the electrodes and the resulting electric field strength. The voltage strength, in turn, depends on the dielectric strength and permittivity of the dielectric fluid. To date, air, which has a relatively low permittivity and dielectric strength, has been used as the dielectric in many applications. The use of dielectric fluids with relatively high permittivity and / or high dielectric strength enables stronger electric fields and thus the generation of higher actuating forces by the actuator.

[0013] Both the stator and actuator elements are enclosed in an insulator housing. This housing isolates the actuator from the environment, providing protection, in particular, from the voltage applied to the electrodes. This is especially important when the actuator is used in an exosuit, as the actuators are positioned relatively close to the user's body, and the user's safety must be guaranteed at all times, even in the event of a short circuit.

[0014] The insulator housing is also flexible and therefore highly elastically deformable. Furthermore, the support matrices are similarly flexible. This allows the stator and actuator elements to be deformed relatively easily and to a considerable degree. Thus, the entire electrostatic actuator is deformable, particularly bendable, making it especially suitable for use in an exosuit. For example, when a joint is bent, the actuator can deform appropriately, thereby providing greater freedom of movement for the exosuit wearer. Despite this flexibility, the actuator's functionality is not, or only minimally, affected by bending. This is made possible primarily by the use of dielectric fluid, which forms an effective dielectric layer between the actuator and stator elements, regardless of the type of deformation.

[0015] The first load-bearing structure is connected to the stator element of the electrostatic actuator according to the invention. Thus, the stator element is indirectly connected to the first body part. The second load-bearing structure is connected to the actuator element of the electrostatic actuator according to the invention, so that the actuator element is indirectly connected to the second body part.

[0016] The actuator is thus arranged between the two load-bearing structures, so that when the actuator is activated, one body part is moved relative to the other. Accordingly, the device according to the invention can, by means of the actuator, support a movement of a person already initiated by muscle power and in this way increase their performance, muscle strength, endurance, etc., or reduce strain and thereby prevent injuries or damage to the human body. Such an actuator can also generate an equal force in both directions, so that movements in both directions, i.e., for bending and straightening, can be generated. Furthermore, the actuator can brake human movements.

[0017] Alternatively, such a device can completely replace human muscle power by generating all the force necessary for relative movement directly from the actuator and transferring it to the corresponding body parts via the respective load-bearing structures. This would allow, for example, the movement of body parts in paralyzed individuals.

[0018] Due to the aforementioned features, particularly the use of the dielectric fluid mentioned, the actuator according to the invention exhibits a particularly high power density, is relatively precisely adjustable with respect to the required force, and can be controlled very accurately. The actuator is therefore particularly well-suited for use in an exosuit. Furthermore, the flexibility of the actuator and its resulting adaptability to the human body result in a particularly high level of wearing comfort for the exosuit.

[0019] According to a particularly preferred embodiment of the present invention, the insulator housing encloses the dielectric fluid. The insulator housing thus seals the interior of the electrostatic actuator from the environment, preventing, in particular, the dielectric fluid from escaping or evaporating from the insulator housing. Additionally, the insulator housing protects the interior of the electrostatic actuator from the ingress of dirt, foreign matter, moisture, and / or similar substances.

[0020] According to a particularly advantageous embodiment of the invention, the dielectric fluid is a liquid. Dielectric fluids are characterized, among other things, by their self-healing properties after an electrical breakdown. Furthermore, the dielectric fluid forms a kind of sliding layer between the stator element and the actuator element, thus enabling relatively low-friction actuation of the actuator element. Liquids are also suitable as dielectrics for an electrostatic actuator due to their high thermal conductivity and their almost complete incompressibility.

[0021] According to a particularly preferred embodiment of the invention, the dielectric fluid has a relative permittivity of greater than 2. The relative permittivity is directly related to the strength of the electric field generated by the electrodes. The stronger the electric field, the greater the force generated by the actuator. With a relative permittivity greater than 2, the use of dielectric fluids ensures that a relatively strong electric field can be generated, such that the force generated by the actuator is large enough to make it suitable for use in an exosuit.

[0022] According to a particularly preferred embodiment of the invention, the actuator is a linear actuator, wherein the relative movement of the actuator element is a linear movement. The actuator electrodes and the stator electrodes are arranged parallel to each other in a row. As a result of the voltage applied to the actuator electrodes and the stator electrodes, attractive or repulsive forces act between the actuator electrodes and the stator electrodes, thereby generating the relative movement between the stator element and the actuator element. The progressive wave-like potential causes a polarization change of the stator / actuator electrodes, resulting in a continuous linear movement of the actuator element. The actuator element of the linear actuator thus performs a translational movement, which is particularly suitable for exerting a tensile and / or compressive force and thus preferably, as part of an exosuit, for generating or supporting relative movement between body parts.Due to its flexibility, the electrostatic actuator according to the invention can be used particularly well as a bendable linear actuator, which enables linear relative movement even in the bent state and is therefore particularly suitable for supporting human musculature in an exosuit due to its adaptability to a predetermined contour.

[0023] In a preferred embodiment of the invention, the insulator housing is made of an electrically non-conductive plastic. For example, the insulator housing could be made of polypropylene (PP) or polyethylene terephthalate (PET). Such plastics offer relatively good electrical insulation properties, are cost-effective, flexible, and relatively lightweight. Furthermore, such plastics are relatively resistant to environmental influences such as UV light, moisture, and aging.

[0024] In a further advantageous embodiment of the invention, both the stator electrode support matrix and the actuator electrode support matrix are designed as thin-film components. The thickness of each individual thin-film component is at most 0.5 mm, and the electrostatic actuator consists of at least two of these thin-film components, namely a first thin-film component as the actuator element and a second thin-film component as the stator element. Furthermore, the thin-film components can be multilayered to increase the force output, i.e., they can have several electrode layers. The use of such thin-film support matrices also ensures the high flexibility of the actuator.

[0025] According to a particularly advantageous embodiment of the invention, the wall thickness of the insulator housing is at most 1.5 mm. This thin wall thickness results in relatively high flexibility of the insulator housing, which also ensures corresponding flexibility of the actuator. Furthermore, the thin-walled design results in a low weight for the actuator, which is particularly advantageous when the electrostatic actuator is used in an exosuit.

[0026] In a preferred embodiment of the invention, the insulator housing has at least one opening through which a force transmission structure connected to the actuator element is guided. By means of the force transmission structure, the actuator element can be indirectly connected inside the insulator housing to an external element to be actuated, for example, to a part of an exosuit. The opening also has a sealing element that seals the interior of the insulator housing from the environment. The sealing element is arranged in the area of ​​the opening between the insulator housing and the force transmission structure and, in particular, prevents the escape of the dielectric fluid from the interior of the insulator housing as well as the ingress of dirt and moisture into the interior of the insulator housing.

[0027] In an alternative embodiment of the invention, the insulator housing at least partially comprises a bellows structure which is connected to the actuator element in a section of the insulator housing. The bellows structure is preferably an integral part of the insulator housing, so that the insulator housing and the bellows structure form a closed, sealed interior space. The bellows structure is oriented with respect to the direction of movement of the actuator element such that the bellows structure is folded or unfolded during the relative movement of the actuator element. The insulator housing section preferably located adjacent to the bellows structure is rigidly connected to the actuator element, so that an external force transmission structure can be connected to the insulator housing section on the outside of the insulator housing.This allows the force transmission structure to be indirectly connected to the actuator element without requiring a direct connection to the interior of the insulator housing. The use of a flexible bellows structure enables the insulator housing section, which is rigidly connected to the actuator element, to move with the actuator element while still ensuring a seal between the insulator housing interior and the environment as an integral part of the insulator housing. Therefore, no separate sealing elements are necessary to seal the insulator housing interior from the environment.

[0028] In a further alternative embodiment of the invention, the insulator housing has at least a partially elastically expandable wall structure. The elastically expandable wall structure is an integral part of the insulator housing, so that the insulator housing forms a closed and externally sealed interior. The elastically expandable wall structure is rigidly connected to the actuator element in a section of the insulator housing. Due to this rigid connection, the insulator housing section follows the movement of the actuator element, with the elastically expandable wall structure expanding and contracting accordingly. An external force transmission structure can be directly connected to the insulator housing section on the outside and thus indirectly to the actuator element.The force transmission structure could, for example, be part of an exosuit or any other structure connected to a body part that needs to be actuated. Due to the use of the elastically expandable wall structure, it is possible to indirectly connect the force transmission structure to the actuator element located inside the insulator housing via the outside of the housing, while still creating a self-contained and sealed insulator housing interior without additional separate sealing points.

[0029] In a particularly preferred embodiment of the invention, electrical conductors for transmitting electrical energy and / or control signals protrude through an opening in the insulator housing and are connected to the stator and actuator electrodes inside the insulator housing. Preferably, several conductors are combined into a single cable, which transmits the control signals from the control unit and supplies the stator and actuator electrodes with the necessary voltage. Additional conductors can also be provided, for example, to transmit information such as sensor data from the actuator to the control unit. Electrical energy can also be transmitted from the actuator to a corresponding unit, for example, if the actuator generates electrical energy as part of a recuperation function.The electrical conductors run through an opening in the insulator housing and to the stator and actuator electrodes, preferably at least partially within or along force transmission structures connected to the actuator. The electrical conductors can, for example, be guided along flexible bands serving as force transmission structures. The electrical conductors are then guided through the insulator housing into its interior, for example, through corresponding openings fitted with sealing elements. Alternatively, the electrical conductors can be embedded within the insulator housing during its manufacture or guided through the openings of the aforementioned tension cables. Furthermore, the electrical conductors can also run within the bands or tension cables, thus protecting them from damage.If the electrical wires run inside the pull cables connected to the actuator, no additional openings need to be provided in the insulator housing. Instead, the electrical wires can be routed through the pull cables into the interior of the insulator housing.

[0030] An embodiment of a device according to the invention for generating or supporting a relative movement between two body parts connected to each other via a joint-like structure with an electrostatic actuator, as well as several embodiments of electrostatic actuators, are shown in the figures and are described below. Figure 1 shows the basic structure of an electrostatic actuator for a device according to the invention in a schematic sectional view. Figure 2A first embodiment of an electrostatic actuator for a device according to the invention is shown in a schematic sectional view. Figure 3 Figure 1 shows a second embodiment of an electrostatic actuator for a device according to the invention in a schematic sectional view. Figure 4 Figure 1 shows a third embodiment of an electrostatic actuator for a device according to the invention in a schematic sectional view. Figure 5 Figure 1 shows an embodiment of a device according to the invention for generating or supporting a relative movement between two body parts connected to each other via a joint-like structure with an electrostatic actuator.

[0031] The Figure 1Figure 1 schematically shows an electrostatic linear actuator 10. This linear actuator 10 comprises a stator element 12 with a stator electrode support matrix 125 formed from a fully flexible thin-film layer, which can be made, for example, from a polyimide serving as an insulator. A plurality of stator electrodes 121 are embedded in the stator electrode support matrix 125, arranged in a row at equal intervals and interconnected in phase. The layer thickness d of this stator electrode support matrix 125 is approximately 0.025 mm.

[0032] The linear actuator 10 further comprises an actuator element 14 which is constructed analogously to the stator element 12. The actuator element 14 comprises an actuator electrode support matrix 145 formed from a fully flexible thin-film layer, which can be made, for example, from a polyimide serving as an insulator. A plurality of actuator electrodes 141 are embedded in the actuator electrode support matrix 145, arranged in a row at equal intervals, with the actuator electrodes 141 being connected to each other in phases. The layer thickness d of this actuator electrode support matrix 145 is also approximately 0.025 mm.

[0033] A gap 18 is formed between the stator element 12 and the actuator element 14, in which a dielectric fluid 16 is located. The dielectric fluid 16 is, for example, a liquid with a relatively high permittivity and good sliding properties.

[0034] A multiphase AC signal is generated by means of external control electronics 50 and an external energy storage device 55 as a voltage source. This multiphase AC signal is applied to the stator electrodes 121 and the actuator electrodes 141, thereby supplying the electrodes 121 and 141 with a multiphase AC voltage. In the present embodiment, corresponding three-phase AC voltages are applied to the electrodes 121 and 141.

[0035] Specifically, voltages are sequentially applied to electrodes 121 and 141, but these voltages are phase-shifted. When these three-phase sinusoidal voltages are applied, wave potentials P develop in the stator element 12 and the actuator element 14. The phase difference between these two wave potentials P generates an electrostatic force between the stator element 12 and the actuator element 14, causing the actuator element 14 to move translationally along the stator element 12 while holding the stator element 12 in place. The high permittivity of the dielectric fluid 16 enables the generation of relatively high electrostatic forces, resulting in a relatively high translational actuation force for the linear actuator 10.

[0036] The stator element 12 and the actuator element 14 are enclosed by a thin-walled and flexible insulator housing 20, which seals the interior of the actuator 10, namely the insulator housing interior 21, from the environment. This seals the dielectric fluid 16 within the insulator housing 20 and protects it from evaporation or leakage. The flexibility of the insulator housing 20 is comparable to that of the carrier matrices 125, 145, making the actuator 10 as a whole flexible and therefore particularly bendable. In addition, the insulator housing 20 is made of an electrically non-conductive material and electrically insulates the insulator housing interior 21 from the environment, thus ensuring electrical safety at all times, especially when using relatively high voltages. The thickness s of the insulator housing is a maximum of 1.5 mm.

[0037] The dielectric fluid 16, which is arranged in the gap 18 between the stator element 12 and the actuator element 14, additionally enables relatively low-friction sliding of the actuator element 14 on the stator element 12 when the electrostatic force generated by the electrodes 121, 141 sets the actuator element 14 in motion. Furthermore, the dielectric fluid 16 forms a lubricating film between the actuator element 14 and an inner wall 201 of the insulator housing 20, whereby the friction between the actuator element 14 and the insulator housing 20 is relatively low, especially when the actuator 10 is bent.

[0038] The in Figure 2 The linear actuator 10 shown corresponds in its basic structure to the one in Figure 1 The linear actuator 10 shown serves as the basis for all embodiments. For clarity, the electrodes 121, 141 are shown in the Figure 2 as in the Figure 3 and 4not shown, their arrangement being the arrangement of electrodes 121, 141 in Figure 1 corresponds.

[0039] In detail, the linear actuator 10 of the Figure 2The insulator housing 20, which has two openings 24 but is otherwise completely closed, seals the insulator housing interior 21, filled with the dielectric fluid 16, from the environment. To transmit the movement of the actuator element 14, a force transmission structure 30 is connected to the actuator element 14. The force transmission structure 30 is preferably formed by two spaced-apart and substantially parallel flexible tension cables 31, the tension cables 31 extending outwards from the actuator element 14 through corresponding openings 24 in the insulator housing 20 in the direction of movement M of the actuator element 14.The pull cables 31 can thus be attached to a first element or structure to be actuated, while the stator element 12 is attached to a second element or structure via a second force transmission structure 32 that runs through the insulator housing 20. This allows relative movement of the actuator element 14 between the two force transmission structures 30 and 32 to be generated. To ensure that the interior of the insulator housing 21 is sealed from the environment despite the pull cables 31 extending from the insulator housing 20, the openings 24 in the insulator housing 20 have sealing elements 34 that seal the gap between the pull cable 31 and the respective corresponding opening 24. In this way, the interior of the insulator housing 21 is completely sealed to the outside. Nevertheless, the movement of the actuator element 14 can be reliably transmitted to the outside.Furthermore, electrical conductors 57 run through the power transmission structures 30, 32 into the insulator housing interior 21, which serve to contact the electrodes 121, 141. Alternatively, corresponding openings with sealing elements can be provided through which the electrical conductors 57 are guided into the insulator housing interior 21.

[0040] Figure 3 Figure 1 shows an alternative embodiment of the electrostatic linear actuator 10, which differs from the one in Figure 20 only in terms of the construction of the insulator housing 20. Figure 2 The linear actuator 10 shown differs. The insulator housing 20 of the in Figure 3The actuator 10 shown is completely enclosed and comprises an integral bellows structure 26 on the side of the actuator element 14 facing away from the stator element 12. On this side of the actuator 10, the bellows structure 26 extends over the entire length and width of the insulator housing 20, with the individual folds 261 being oriented such that the bellows structure 26 can fold and unfold in the direction of movement M of the actuator element 14. The inner surface of the bellows structure 26 is rigidly connected to the actuator element 14 in an insulator housing section 25. In the insulator housing section 25, the bellows structure 26 is flat, i.e., it has no folds there. In this way, a planar connection with the actuator element 14 is created.

[0041] In Figure 3The actuator element 14 is positioned approximately centrally to the stator element 12 with respect to the direction of movement M, so that the insulator housing section 25 is also positioned approximately centrally to the stator element 12 with respect to the direction of movement M. With respect to the view of the Figure 3The bellows structure 26 has the same number of folds 261 to the right and left of the insulator housing section 25. These folds unfold on one side of the insulator housing section 25 and unfold on the other side, depending on the direction of movement M. This allows an external force transmission structure 30 to act on the actuator element 14 from the outside through the insulator housing 20 within the insulator housing section 25, which moves with the actuator element 14. Furthermore, another force transmission structure 32 is connected to the stator element 12 through the insulator housing 20. The sealing of the insulator housing 20 at the corresponding penetration points is achieved, for example, by overmolding the force transmission structures 30 and 32 during the manufacture of the insulator housing 20. The contacting of the electrodes 121 and 141 is analogous to that of the actuator 10. Figure 2This is achieved by means of electrical conductors 57 running within the power transmission structures 30, 32. The insulator housing 20 with the bellows structure 26 thus forms a self-contained unit, so that the interior of the insulator housing 21 is completely insulated from the outside. The flexibility and insulating properties of the insulator housing 20 are achieved by preferably manufacturing the insulator housing 20 from polypropylene (PP) or polyethylene terephthalate (PET) and by making it approximately 0.5 mm thick, which makes it relatively light, flexible, and electrically insulating.

[0042] Figure 4 shows another one on the in Figure 1 The actuator 10 shown is an embodiment of a linear actuator 10 with an insulator housing 20 that differs from the other embodiments. The insulator housing 20 of the actuator 10 shown is a linear actuator 10 based on an actuator 10 with an insulator housing 20 that differs from the other embodiments shown. Figure 4The actuator 10 shown has an integral wall structure 28 made of a particularly elastic, stretchable material, for example, a silicone-based plastic, and is approximately 0.1 mm thick. The elastically stretchable wall structure 28 is located on the side of the actuator element 14 facing away from the stator element 12 and is rigidly connected to the actuator element 14 within an insulator housing section 25. The insulator housing section 25 moves together with the actuator element 14 when the latter is moved, whereby the elastic wall sections 281 of the wall structure 28 adjacent to the direction of movement M stretch or contract. For one of the wall sections 281 to contract, the elastic wall sections 281 in the Figure 4The actuator element 14 is prestressed in the position shown. The prestress should be large enough that the respective elastic wall section 281 can contract without wrinkles when the actuator element 14 is moved into its respective end position.

[0043] Due to the fixed connection between the actuator element 14 and the moving insulator housing section 25, an external force transmission structure 30 can act on the actuator element 14 through the insulator housing 20. The contacting of the electrodes 121, 141 is analogous to that of the actuator 10. Figure 2 realized by means of electrical lines 57 running in the power transmission structures 30, 32. Consequently, the actuator 10 of the Figure 4 in contrast to the one in Figure 2In the illustrated embodiment of the actuator 10, there are no external sealing points, so that the insulator housing 20 with the elastic wall structure 28 forms a self-contained unit, and thus the interior of the insulator housing 21 is completely insulated from the outside. The remaining walls of the insulator housing 20 are designed to be flexible, analogous to the previously mentioned embodiments, and are made of an electrically insulating material. This can either be the same elastically stretchable material from which the elastic wall structure 28 is made, or another flexible plastic that is integrally bonded to the elastic material of the wall structure 28, thus ensuring the tightness of the insulator housing 20.

[0044] Figure 5Figure 100 shows an exemplary device 100 for generating or supporting relative movement between two body parts 42, 44 connected to each other via a joint-like structure 40. The first body part 42 is a human torso 42, which is connected to the second body part 44, namely a thigh 44, via the joint-like structure 40, namely a hip joint 40. The device 100, which can also be referred to as an exosuit, comprises a first load-bearing structure 106 that encircles the torso 42 of the wearer in the pelvic region like a belt. A second load-bearing structure 108 encircles the thigh 44 of the wearer. Thus, both load-bearing structures 106, 108 are connected to the respective body parts 42, 44 in such a way that a force can be transmitted between the two body parts 42, 44 via the load-bearing structures 106, 108. The force is applied here by way of example by an electrostatic linear actuator 10 according to Figure 10. Figure 4 generated.

[0045] The actuator 10 is connected to the load-bearing structures 106, 108 via force transmission structures 30, 32, for example flexible bands 31, 33, wherein the first load-bearing structure 106 is connected to the stator element 12 via flexible bands 33 and via the insulator housing 20, and the second load-bearing structure 108 is connected to the elastically stretchable wall structure 26 of the linear actuator 10 via flexible bands 33. Figure 4 The actuating ligaments 31 are connected to the actuator element 14. By actuating the actuator 10, for example, when the actuator element 14 is moved towards the torso 42, the leg of the bearer can be pivoted relative to the torso 42 via the load-bearing structure 108 on the thigh 44 and thereby raised, with the hip joint 40 forming the pivot point. By moving the actuator element 14 in the opposite direction, the leg can be extended again. This can, for example, make climbing stairs easier.

[0046] The embodiment shown here is one of many possible embodiments. The invention is therefore not limited to the present embodiment. For example, the electrodes 121, 141 arranged in series in the stator element 12 and / or the actuator element 14 could be offset from one another with respect to the thickness direction, i.e., not arranged on a single plane. Furthermore, instead of one, for example, two separate voltage sources could be provided, supplying the stator element 12 and the actuator element 14 separately and thereby exciting them at different frequencies. In addition, instead of a three-phase voltage, for example, a four-phase voltage could be provided to supply the actuator 10. In the embodiment shown in Figure 2Alternatively, the actuator 10 shown could be provided with only a single pull cable 31. Furthermore, the electrical lines 57 could alternatively run outside or away from the force transmission structures 30, 32. The position at which the force application structures 30, 32 act on the stator element 12 or on the actuator element 14 could also vary. Alternatively, the Figure 4 The first load-bearing structure 106 shown is connected to the actuator element 14, and the second load-bearing structure 108 is connected to the stator element 12. Furthermore, instead of a dielectric fluid 16, a dielectric gas can be used as the dielectric between the stator element 12 and the actuator element 14.

Claims

1. Apparatus (100) for generating or assisting a relative movement between two body parts (42, 44) which are connected to one another via a joint-like structure (40), having a first load-receiving structure (106) which is attached to a first body part (42), having a second load-receiving structure (108) which is attached to a second body part (44) which is pivotable relative to the first body part (42), and having an electrostatic actuator (10), comprising: a stator element (12) having a plurality of stator electrodes (121) which are embedded in a stator electrode carrier matrix (125), an actuator element (14) which is movable relative to the stator element (12) and has a plurality of actuator electrodes (141) which are embedded in an actuator electrode carrier matrix (145), wherein the actuator element (14) is movable by an electrostatic force which acts between the stator electrodes (121) and the actuator electrodes (141), wherein a dielectric fluid (16) is arranged in a gap (18) between the stator element (12) and the actuator element (14), and an insulator housing (20) which encloses the stator element (12) and the actuator element (14), wherein both the carrier matrices (125, 145) and the insulator housing (20) are of formed flexibly, and wherein the first load-receiving structure (106) is connected to the stator element (12) of the electrostatic actuator (10) and the second load-receiving structure (108) is connected to the actuator element (14) of the electrostatic actuator (10).

2. Apparatus (100) according to claim 1, characterized in that the insulator housing (20) encloses the dielectric fluid (16) and seals the electrostatic actuator (10) with respect to the outside.

3. Apparatus (100) according to claim 1 or 2, characterized in that the dielectric fluid (16) is a liquid.

4. Apparatus (100) according to claim 3, characterized in that the relative permittivity of the dielectric fluid (16) is greater than 2.

5. Apparatus (100) according to one of the preceding claims, characterized in that the actuator (10) is a linear actuator, wherein the relative movement of the actuator element (14) is a linear movement.

6. Apparatus (100) according to one of the preceding claims, characterized in that the insulator housing (20) is produced from an electrically non-conductive plastic.

7. Apparatus (100) according to one of the preceding claims, characterized in that the carrier matrices (125, 145) are formed as a thin-film, respectively.

8. Apparatus (100) according to claim 7, characterized in that the thickness (d) of the thin-film is at most 0.5 mm.

9. Apparatus (100) according to one of the preceding claims, characterized in that the wall thickness (s) of the insulator housing (20) is at most 1.5 mm.

10. Apparatus (100) according to one of the preceding claims, characterized in that the insulator housing (20) has at least one opening (24) through which a force transmission structure (30) connected to the actuator element (14) is guided, wherein an insulator housing interior (21) is sealed off from the surroundings by means of at least one sealing element (34).

11. Apparatus (100) according to one of claims 1-9, characterized in that the insulator housing (20) at least partially has a bellows structure (26) which is connected to the actuator element (14) in an insulator housing portion (25).

12. Apparatus (100) according to one of claims 1-9, characterized in that the insulator housing (20) at least partially has an elastically expandable wall structure (28) which is connected to the actuator element (14) in an insulator housing portion (25).

13. Apparatus (100) according to one of the preceding claims, characterized in that electrical lines (57) for transmitting electrical energy and / or control signals project through an opening (24) of the insulator housing (20) and are connected to the stator electrodes (121) and actuator electrodes (141) in the insulator housing interior (21).

14. Apparatus (100) according to one of the preceding claims, characterized in that the electrical lines (57) run at least partially in or on force transmission structures (30, 32) connected to the actuator (10).

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