Tactile sensor

Abstract

The present disclosure relates to a finger assembly for a manipulation device comprising a rigid body and a deformable membrane received within an aperture, wherein an outer surface of the deformable membrane comprises a gripping surface arranged to grip an object being manipulated, and an inner surface of the deformable element comprises a visual marker, the finger assembly further comprising a reflective surface received within the rigid body opposite the deformable membrane to reflect an image of the visual marker, and an optical sensor arranged to view the visual marker on the inner surface of the deformable membrane and the reflected image of the visual marker to provide a stereoscopic view of the visual marker.

Description

Technical Field

[0001] The present disclosure relates to a tactile sensor for a finger assembly of an operating device. More particularly, the present invention relates to a camera-based tactile sensor. Aspects of the present invention relate to the finger assembly itself, the operating device, and a control device for the operating device.

Background Art

[0002] An automatic picking or sorting system requires an operating device that can select an item from a first container such as a tote or another type of storage unit, grip the item, and then move the item to a second container such as a bag. When manipulating an item, it is beneficial if the finger assembly that grips the item is appropriately small so that the finger assembly can access containers of different sizes without being obstructed by the containers. It is particularly beneficial to minimize their thickness relative to their width so that they can access narrow spaces while maintaining an appropriately large gripping surface area. Minimizing the size of the finger assembly can also have a beneficial effect on their operability. However, the desire for a smaller finger assembly is contrary to the requirement for a higher tactile response, which requires greater complexity within the finger assembly itself so that the finger assembly can manipulate a wider range of objects.

[0003] The present invention has been devised in view of such a background.

Summary of the Invention

[0004] In a first aspect, the present invention provides a finger assembly for an operating device. The finger assembly includes a rigid body having an opening, a deformable membrane received within the opening, wherein an outer surface of the deformable membrane has a gripping surface arranged to grip an object being manipulated, an inner surface of the deformable element has a visual marker, a reflecting surface received within the rigid body opposite the deformable membrane so as to reflect an image of the visual marker, and an optical sensor arranged to view the visual marker on the inner surface of the deformable membrane and the reflected image of the visual marker so as to provide stereoscopic vision. This absence of a second optical sensor for providing stereoscopic vision, for example, minimizes the thickness of the finger assembly and provides an opportunity to reduce the number of electrical components housed within the finger assembly compared to a finger assembly having two or more optical sensors, which significantly affects the form factor of the finger assembly. These are particularly desirable features as they not only reduce the volume of the finger assembly and improve its accessibility while maintaining the surface area of the gripping surface of the finger assembly, but also reduce capital and operating costs.

[0005] Preferably, the rigid body includes a housing and a frame fastened to the housing, the frame has an opening, and the deformable membrane is sandwiched between the housing and the frame.

[0006] Preferably, the surface area of the frame used to sandwich the deformable membrane is larger than the surface area of the housing used to sandwich the deformable element.

[0007] Preferably, the surface area of the housing used to sandwich the deformable element is formed on a rib surrounding the inner peripheral edge of the housing.

[0008] Preferably, the optical sensor is arranged such that its optical axis forms an acute angle with a plane defined by the intersection between the housing and the frame.

[0009] Preferably, the optical sensor is arranged such that its optical axis does not intersect the reflecting surface.

[0010] Preferably, the reflective surface and the deformable membrane are arranged convergently in one direction from the optical sensor.

[0011] Preferably, the reflective surface and the deformable membrane meet at the end of the rigid body on the side opposite to the optical sensor.

[0012] Preferably, the reflective surface is arranged so as to form an acute angle with the plane defined by the intersection between the housing and the frame.

[0013] Preferably, the visual marker comprises alternating markers of contrasting colors. Alternatively, the visual marker forms a grid comprising a plurality of rows of markers, the color of the markers within any one row being the same, and the color of the markers in at least one of the rows being different from the color of the markers in the other rows. Preferably, the color of the markers in each row is different from the color of the markers in the other rows.

[0014] Preferably, the finger assembly further comprises a light source for illuminating the interior of the finger assembly. Preferably, the light source is adjacent to the reflective surface. The light source is particularly preferred when the housing and the frame are opaque to reduce the influence of ambient light and the optical sensor can view the visual markers on the inner surface of the deformable membrane and the reflected image of the visual markers from the reflective surface, ensuring sufficient and controllable illumination inside the finger assembly. Arranging the light source adjacent to the reflective surface enhances the illumination inside the finger assembly.

[0015] In a second aspect, the present invention provides a control device for an operating device, the operating device comprising: a finger assembly according to the first aspect; an inflation means operably coupled to the finger assembly, the inflation means being configured to receive a control signal and pressurize the interior of the finger assembly depending on the control signal; the control device comprising: an input section configured to receive a first visual data input signal from an optical sensor, the first visual data input signal showing an image of a visual marker on the inner surface of a deformable membrane, and a second visual data input signal from the optical sensor, the second visual data input signal showing a reflected image of the visual marker on the inner surface of the deformable membrane; and a processor configured to determine a deformation of the deformable membrane depending on the first visual data input signal and the second visual data input signal, determine a force acting on the deformable membrane based on the deformation, and generate a control signal for the inflation means to increase the pressure in the finger assembly if the force acting on the deformable membrane is less than a target force, or generate a control signal for the inflation means to reduce the pressure in the finger assembly if the force acting on the deformable membrane is greater than the target force.

[0016] Preferably, the control device is further configured to initialize a first plurality of image points, wherein each image point of the first plurality of image points indicates the position of a respective marker of the visual marker in the first visual data input signal, initialize a second plurality of image points, wherein each image point of the second plurality of image points indicates the position of a respective marker of the visual marker in the second visual data input signal, determine a disparity map depending on the first plurality of image points and the second plurality of image points, and determine the shape of the deformable membrane depending on the disparity map.

[0017] In a third aspect, the present invention provides an operating device comprising: a finger assembly according to the first aspect; an inflation means operably coupled to the finger assembly, the inflation means being configured to receive a control signal and pressurize the interior of the finger assembly depending on the control signal; and a control device according to the second aspect.

[0018] Next, these and other aspects of the present invention will be described by way of example only with reference to the accompanying drawings.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Embodiments for Carrying Out the Invention

[0020] In the drawings, like features are denoted by like reference numerals as required.

[0021] In the following description, some specific details are included to provide a complete understanding of the disclosed examples. However, those skilled in the art will recognize that other examples may be implemented without one or more of these specific details, or with other components, materials, etc., and that structural changes may be made without departing from the scope of the invention as defined in the appended claims. Further, in the following description, any reference to terms having an implied orientation is not intended to be limiting and refers only to the orientation of the features shown in the accompanying drawings. In some cases, well-known features or systems such as processors, sensors, memory devices, network interfaces, fasteners, electrical connectors, etc. are not illustrated or described in detail in order to avoid unnecessarily obscuring the description of the disclosed embodiments.

[0022] Throughout this specification and the appended claims, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", are to be construed in an open, inclusive sense, meaning "including, but not limited to".

[0023] Throughout this specification, references to "one", "an", or "another" in connection with "embodiments", "examples", are meant that a particular feature, structure, or characteristic described in connection with the embodiment, example, or implementation is included in at least one embodiment, example, or implementation. Thus, appearances of the phrases "in one embodiment" or similar expressions throughout this specification are not necessarily all referring to the same embodiment. Further, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments, examples, or implementations.

[0024] As used in this specification and the appended claims, it should be noted that the forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise. Also, it should be noted that the term "or" is generally used in the sense of "and / or" unless the context clearly dictates otherwise.

[0025] FIG. 1 shows a schematic diagram of an operating device 10 according to an embodiment of the present invention, comprising a first finger assembly 12a facing a second finger assembly 12b and a control device 14. Each of the first and second finger assemblies 12a, 12b includes a deformable membrane (not shown) having a gripping surface arranged on its outer surface for gripping an object 16 being operated, together with an optical sensor housed inside the finger assemblies 12a, 12b for viewing the deformation of the deformable membrane while the object 16 is being operated. The operating device 10 further comprises a first actuator 18a and a first pressure adjusting means 20a, both of which are associated with the first finger assembly 12a, and a second actuator 18b and a second pressure adjusting means 20b are associated with the second finger assembly 12b. The first and second pressure adjusting means 20a, 20b are connected to their associated finger assemblies 12a, 12b by respective pressure lines 27a, 27b. The control device 14 comprises an electronic processor 21 having one or more electrical inputs for receiving first and second visual data input signals 23a, 23b from the optical sensors, and one or more electrical outputs for outputting one or more control signals 22a, 22b, 24a, 24b to the first and second actuators and pressure adjusting means 18a, 18b, 20a, 20b depending on the visual data input signals 23a, 23b. For example, the control device 14 is configured to output a first actuation control signal 22a for moving the first finger assembly 12a based on the first visual data input signal 23a. The first actuator 18a receives the first actuation control signal 22a and is configured to move the first finger assembly 12a relative to the second finger assembly 12b depending on the first actuation control signal 22a. Similarly, the control device 14 may also output a second actuation control signal 22b for moving the second finger assembly 12b based on the second visual data input signal 23b. The second actuator 18b receives the second actuation control signal 22b and is configured to move the second finger assembly 12b relative to the first finger assembly 12a depending on the second actuation control signal 22b. These movements are centered around a plurality of axes of movement and include rotation of one of the first or second finger assemblies 12a, 12b relative to the other of the first or second finger assemblies 12a, 12b.Such movement may enable the object 16 to be grasped between the first and second finger assemblies 12a, 12b. The first and second finger assemblies 12a, 12b may also be movable together such that the object 16 grasped between the first and second finger assemblies 12a, 12b can be moved from the first position to the second position. The control device 14 is further configured to output inflation control signals 24a, 24b for controlling the first or second pressure adjustment means 20a, 20b depending on the respective visual data input signals 23a, 23b in order to change the pressure inside the first or second finger assembly 12a, 12b and thereby change the compliance of their respective deformable elements. Specifically, the control device 14 is arranged to output a first inflation control signal 24a based on the first visual data input signal 23a, and the first pressure adjustment means 20a is configured to receive the first inflation control signal 24a and pressurize the first finger assembly 12a depending on the first inflation control signal 24a. Similarly, the control device 14 is arranged to output a second inflation control signal 24b based on the second visual data input signal 23b, and the second pressure adjustment means 20b is configured to receive the second inflation control signal 24b and pressurize the second finger assembly 12b depending on the second inflation control signal 24b in order to change the compliance of its deformable membrane. To generate the control signals 22a, 22b, 24a, 24b, the control device 14 further comprises an electronic processor 21 electrically coupled to and a memory device 25 storing instructions. The electronic processor 21 is configured to access the memory device 25 and execute the instructions stored thereon to perform the process 100 shown in FIG. 2.

[0026] Referring to FIG. 2, process 100 starts at step 102 and proceeds to step 104, where the deformation of the deformable membrane of finger assembly 12’ during the manipulation of object 16 is determined depending on visual data input signal 23’. The process 100 then proceeds to step 106, where the force acting on the deformable membrane is determined based on the deformation determined in step 104, and then proceeds to step 108. If at step 108 it is determined that the force acting on the deformable membrane is less than the target force, the process proceeds to step 110, where an inflation control signal 24’ is generated for increasing the pressure within finger assembly 12’ before the process ends at step 112. If at step 108 it is determined that the force acting on the deformable membrane is not less than the target force, process 100 proceeds to step 114, where it is determined whether the force is equal to or greater than the target force. If it is determined that the force is equal to the target force, process 100 proceeds to step 112 and ends there. On the other hand, if at step 114 it is determined that the force is not equal to but greater than the target force, process 100 proceeds to step 116, where an inflation control signal 24’ is generated for reducing the pressure within finger assembly 12’ before process 100 proceeds to step 112 and ends. The target force can be selected at any point prior to step 106 and can be predetermined based on the characteristics of the object 16 being manipulated or a combination of such characteristics such as its shape, weight, rigidity, fragility, etc. In this way, the force exerted by the deformable membrane on the object 16 being manipulated can be sensed and increased or decreased according to the characteristics of the object 16.

[0027] Figure 3 shows a finger assembly 12' according to an embodiment of the present invention that is suitable for use in the operating device 10. The finger assembly 12' includes a rigid body, generally indicated at 26, having an opening 28 within which a deformable membrane 30 is received. The deformable membrane 30 can be formed, for example, from two layers of flexible silicon material that are firmly connected to each other by using an adhesive. The outer surface 31 of the deformable membrane 30 includes a gripping surface 32 that is arranged to grip the object 16 being manipulated, while the inner surface 33 of the deformable membrane 30 includes a visual marker.

[0028] Referring to FIG. 4, the rigid body 26 includes a housing 34 and a frame 36 configured to be fixed to the housing 34. The frame 36 can be adhered to the housing 34, or it can be screwed or clamped to the housing 34 using a suitable mechanism that allows straightforward access to the inside of the finger assembly 12' when the deformable membrane 30 or any other component housed within the finger assembly 12' needs to be replaced. The deformable membrane 30 is disposed between the housing 34 and the frame 36 so as to be clamped therebetween when the finger assembly 12' is assembled. The finger assembly 12' further includes a reflective surface 38 and an optical sensor 40 having a single optical axis, such as a complementary metal oxide semiconductor (CMOS) or charge coupled device (CCD) camera. The reflective surface 38 is disposed on the side facing the deformable membrane 30 within the rigid body 26 so as to reflect an image of the visual marker on the inner surface 33 of the deformable membrane 30. A flow path 42 is also provided within the finger assembly 12' to provide fluid communication between the inside of the finger assembly 12' and its respective pressure regulating means 20' through its respective pressure lines 27'. A light source 44, such as a light emitting diode (LED), can also be provided to illuminate the inside of the finger assembly 12'. The use of the light source 44 is particularly preferred to ensure sufficient and controllable illumination inside the finger assembly 12' when the housing 34 and the frame 36 are made opaque to reduce the influence of ambient light. In this embodiment, the light source 44 is disposed adjacent to the reflective surface 38, whereby direct light from the light source 44 is reflected to enhance the illumination inside the finger assembly 12'.

[0029] FIG. 5 is a schematic cross-sectional view of the finger assembly 12' showing the deformable membrane 30 sandwiched between the housing 34 and the frame 36. The housing 34 and the frame 36 each include respective ridges 46, 48 that define opposing clamping surfaces 50, 52 for holding the deformable membrane 30 in a predetermined position. The ridge 46 of the housing 34 surrounds the inner peripheral edge 54 of the housing 34, and the ridge 48 of the frame 36 defines the opening 28. The ridge 48 of the frame 36 is wider than the ridge 46 of the housing 34, and thus the area of the clamping surface 52 of the frame 36 is larger than the area of the clamping surface 50 of the housing 34. Accordingly, for a given clamping force, the pressure applied to the inner surface 33 of the deformable membrane 30 by the clamping surface 50 of the housing 34 is relatively greater than the pressure applied to the outer surface 31 of the deformable membrane 30 by the clamping surface 52 of the frame 36. This is desirable to avoid leakage from within the finger assembly 12' when the interior of the finger assembly 12' is pressurized.

[0030] As described above, the inner surface 33 of the deformable membrane 30 is provided with visual markers, and FIGS. 6a-6c show three examples of visual markers generally designated 56, all of which are suitable for use with the finger assembly 12'. The first two examples of visual markers 56 shown in FIGS. 6a and 6b can be generalized in that they comprise alternating markers of contrasting colors. The deformable membrane 30 is generally elongated insofar as it has major and minor perpendicular axes 58, 60 to which it is orthogonal. A first example of a visual marker 56 shown in FIG. 6a comprises a plurality of straight lines having contrasting colors. In this example, the straight lines extend across the inner surface 33 of the deformable membrane 30 in the direction of the minor axis 60 and alternate between contrasting colors in the direction of the major axis 58. A second example of a visual marker 56 shown in FIG. 6b comprises a monochromatic 6×11 grid or square array that is contrastive like a checkerboard. In a third example shown in FIG. 6c, the visual marker 56 comprises a plurality of circular markers or dots arranged in a plurality of rows of markers extending in the direction of the minor axis 60. The circular markers forming each row are the same color, but the color of the markers in each row is different from the color of the markers in other rows. Using rows of different colors provides additional visual information to the optical sensor 40 about the sequence of the rows. This can be particularly beneficial when the deformation of the deformable membrane 30 causes one or more of the rows to be out of view of the optical sensor 40. FIGS. 6a-6c show only three examples of visual markers 56, but it should be understood that the visual marker 56 can take a wide variety of forms, for example, one or more or combinations of diagonal lines, curves, intersecting lines, regular and / or irregular polygons, lines, and / or 2D or 3D shapes, etc. of different colors and / or shades. Thus, while there are advantages and benefits to selecting one type of visual marker 56 over another, it should be understood that the specific nature of the visual marker 56 is not important to the teachings of the present invention.

[0031] FIG. 7 is a schematic cross-sectional view of the finger assembly 12' showing the orientation of the optical sensor 40. The reflective surface 38 and the deformable membrane 30 are convergently arranged in a direction extending from the optical sensor 40 so as to form an acute angle α with a plane 62 defined by the intersection between the housing 34 and the frame 36. Preferably, the reflective surface 38 and the deformable membrane 30 are connected at the end of the rigid body 26 on the side opposite to the optical sensor 40, minimizing the thickness of the finger assembly 12' in that region. In this example, the optical sensor 40 is arranged such that an acute angle β is formed between its optical axis 64 and the plane 62. Generally, the optical sensor 40 is arranged here to view the visual markers 56, which are illustrated by a series of vertical lines, so that their positions in three dimensions can be determined. For this purpose, the optical sensor 40 is directed to receive, with respect to the reflective surface 38, two images, namely, i) a direct image 70 of the visual marker 56 along its optical axis 64, and ii) a reflected image 72 of the visual marker 56 from the reflective surface 38 along a second optical axis 74 (see FIG. 8). The reflected image 72 provides an image equivalent to a direct image from a virtual optical sensor 76, which, when combined with the direct image 70 from the optical sensor 40, can provide a stereoscopic view of the visual marker 56, from which the deformation of the deformable membrane 30 can be determined without the need for a second optical sensor. That is, the reflective surface 38 provides a viewing perspective of the visual marker 56 that is different from the viewing perspective of the optical sensor 40 without the space that would be required by a second optical sensor to provide the desired viewing perspective. This is particularly desirable because the absence of a second optical sensor provides a mechanism for minimizing the thickness of the rigid body 26 and reducing the number of electrical components compared to a finger assembly with two or more optical sensors, which greatly affects the form factor of the finger assembly 12'. These are particularly desirable features as they not only reduce the volume of the finger assembly 12' and improve its accessibility to narrow spaces while maintaining the size of the gripping surface 32, but also reduce capital and operating costs.

[0032] As described above, the electrical input of the electronic processor 21 is configured to receive first and second visual data input signals 23' from the optical sensor 40, and the first and second visual data input signals 23' respectively show the direct image 70 and the reflected image 72 of the visual marker 56. Next, the electronic processor 21 accesses the memory device 25 and executes the instructions stored thereon to determine the deformation of the deformable membrane 30 depending on the first and second visual data input signals 23' according to step 104 of the process 100 shown in FIG. 2. To perform this step, the electronic processor 21 executes the process 200 shown in FIG. 9. The process 200 starts at step 202 and proceeds to step 204, where a plurality of first and second image points are initialized, and here each image point of the plurality of first and second image points respectively indicates the position of each mark of the visual marker 56 within the first and second visual data input signals 23'. From here, the process 200 proceeds to step 206, where a disparity map is generated depending on the plurality of first and second image points. Then, at step 208, before the process 200 ends at step 210, the deformation of the deformable membrane 30 is determined based on the disparity map.

[0033] The foregoing description is presented for purposes of illustration only and is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Modifications and variations may be made to the described embodiments without departing from the scope of the invention as defined in the appended claims. The matters described in the claims of the patent application at the time of filing are appended as they are below. [C1] A finger assembly for an operating device, wherein the finger assembly comprises a rigid body having an opening, a deformable membrane received within the opening, wherein an outer surface of the deformable membrane comprises a gripping surface arranged to grip an object being operated, and an inner surface of the deformable element comprises a visual marker, a reflecting surface received within the rigid body opposite the deformable membrane so as to reflect an image of the visual marker, an optical sensor arranged to view the visual marker on the inner surface of the deformable membrane and the reflected image of the visual marker so as to provide a stereoscopic view of the visual marker, A finger assembly comprising. [C2] The finger assembly according to C1, wherein the rigid body comprises a housing and a frame fastened to the housing, the frame comprises the opening, and the deformable membrane is sandwiched between the housing and the frame. [C3] The finger assembly according to C2, wherein a surface area of the frame used to sandwich the deformable membrane is larger than a surface area of the housing used to sandwich the deformable element. [C4] The finger assembly according to C3, wherein the surface area of the housing used to sandwich the deformable element is formed on a rib surrounding an inner peripheral edge of the housing. [C5] The finger assembly according to any one of C2 to 4, wherein the optical sensor is arranged such that an acute angle is formed between its optical axis and a plane defined by an intersection between the housing and the frame. [C6] The finger assembly according to any one of C1 to 5, wherein the optical sensor is arranged such that its optical axis does not intersect the reflecting surface. [C7] The finger assembly according to any one of C1 to 6, wherein the reflecting surface and the deformable membrane are arranged convergently in one direction from the optical sensor. [C8] The finger assembly according to C7, wherein the reflecting surface and the deformable membrane are connected at an end of the rigid body on the side opposite to the optical sensor. [C9] The finger assembly according to any one of C2 to 8, wherein the reflecting surface is arranged such that an acute angle is formed between it and a plane defined by an intersection between the housing and the frame. [C10] The finger assembly according to any one of C1 to 9, wherein the visual marker comprises alternating markers of contrasting colors. [C11] The visual marker forms a grid comprising a plurality of rows of markers, the color of the markers in any one row being the same, and the color of the markers in at least one of the rows being different from the color of the markers in the other rows, the finger assembly according to any one of C1 to 9. [C12] The finger assembly according to C11, wherein the color of the markers in each row is different from the color of the markers in the other rows. [C13] The finger assembly according to any one of C1 to 12, further comprising a light source for illuminating the interior of the finger assembly. [C14] The finger assembly according to C13, wherein the light source is adjacent to the reflective surface. [C15] A control device for an operating device, wherein the operating device is The finger assembly according to any one of C1 to 14, and Inflation means operably coupled to the finger assembly, the inflation means being configured to receive a control signal and pressurize the interior of the finger assembly depending on the control signal. The control device is An input unit configured to receive a first visual data input signal from the optical sensor, the first visual data input signal showing an image of the visual marker on the inner surface of the deformable membrane, and a second visual data input signal from the optical sensor, the second visual data input signal showing a reflected image of the visual marker on the inner surface of the deformable membrane. A processor, Determining the deformation of the deformable membrane depending on the first visual data input signal and the second visual data input signal, Determining the force acting on the deformable membrane based on the deformation, and When the force acting on the deformable membrane is less than a target force, generating a control signal for the inflation means to increase the pressure in the finger assembly, or When the force acting on the deformable element is greater than the target force, generating a control signal for the inflation means to reduce the pressure in the finger assembly. A processor configured to perform the above, and A control device comprising the above. [C16] The control device is Initializing a first plurality of image points, wherein each image point of the first plurality of image points indicates the position of each mark of the visual marker in the first visual data input signal. Initializing a second plurality of image points, wherein each image point of the second plurality of image points indicates the position of each mark of the visual marker in the second visual data input signal, Determining a disparity map depending on the first plurality of image points and the second plurality of image points, Determining the shape of the deformable membrane depending on the disparity map, The control device according to C15, further configured to perform the above. [C17] An operating device, The finger assembly according to any one of C1 to 14, Inflation means operably coupled to the finger assembly, the inflation means being configured to receive a control signal and pressurize the interior of the finger assembly depending on the control signal, The control device according to C15 or 16, An operating device comprising the above.

Claims

1. A finger assembly for an operating device, wherein the finger assembly comprises: A rigid body having an opening; A deformable membrane received within the opening, wherein an outer surface of the deformable membrane comprises a gripping surface arranged to grip an object being operated, and an inner surface of the deformable element comprises a visual marker; A reflective surface received within the rigid body opposite the deformable membrane so as to reflect an image of the visual marker; An optical sensor arranged to view the visual marker on the inner surface of the deformable membrane and the reflected image of the visual marker so as to provide stereoscopic vision of the visual marker; Wherein the optical sensor is arranged such that its optical axis does not intersect the reflective surface. A finger assembly comprising the above.

2. The rigid body comprises a housing and a frame fastened to the housing, the frame has the opening, and the deformable membrane is clamped between the housing and the frame. The finger assembly according to claim 1.

3. The surface area of the frame used to clamp the deformable membrane is larger than the surface area of the housing used to clamp the deformable element. The finger assembly according to claim 2.

4. The surface area of the housing used to clamp the deformable element is formed on a rib surrounding the inner peripheral edge of the housing. The finger assembly according to claim 3.

5. The optical sensor is arranged such that its optical axis forms an acute angle with a plane defined by the intersection between the housing and the frame. The finger assembly according to any one of claims 2 to 4.

6. The reflective surface and the deformable membrane are arranged convergently in one direction from the optical sensor. The finger assembly according to any one of claims 1 to 5.

7. The reflective surface and the deformable membrane are connected at an end of the rigid body opposite the optical sensor. The finger assembly according to claim 6.

8. The reflective surface is arranged such that it forms an acute angle with a plane defined by the intersection between the housing and the frame. The finger assembly according to any one of claims 2 to 5.

9. The visual marker comprises alternating markers of contrasting colors. The finger assembly according to any one of claims 1 to 8.

10. The visual marker forms a grid including a plurality of rows of markers, the color of the markers in any one row being the same, and the color of the markers in at least one of the rows being different from the color of the markers in other rows, the finger assembly according to any one of claims 1 to 8.

11. The finger assembly according to claim 10, wherein the color of the markers in each row is different from the color of the markers in the other rows.

12. The finger assembly according to any one of claims 1 to 11, further comprising a light source for illuminating the interior of the finger assembly.

13. The finger assembly according to claim 12, wherein the light source is adjacent to the reflecting surface.

14. A control device for an operating device, the operating device the finger assembly according to any one of claims 1 to 13, an inflation means operably coupled to the finger assembly, the inflation means being configured to receive a control signal and pressurize the interior of the finger assembly depending on the control signal, the control device an input section configured to receive a first visual data input signal from the optical sensor, the first visual data input signal showing an image of the visual marker on the inner surface of the deformable membrane, and a second visual data input signal from the optical sensor, the second visual data input signal showing a reflected image of the visual marker on the inner surface of the deformable membrane, a processor determining deformation of the deformable membrane depending on the first visual data input signal and the second visual data input signal, determining a force acting on the deformable membrane based on the deformation, and when the force acting on the deformable membrane is less than a target force, generating a control signal for the inflation means to increase the pressure in the finger assembly, or when the force acting on the deformable element is greater than the target force, generating a control signal for the inflation means to reduce the pressure in the finger assembly, a processor configured to perform a control device comprising.

15. The control device initializing a first plurality of image points, wherein each image point of the first plurality of image points indicates the position of each mark of the visual marker in the first visual data input signal, Initializing a second plurality of image points, wherein each image point of the second plurality of image points indicates the position of each mark of the visual marker in the second visual data input signal; Determining a disparity map depending on the first plurality of image points and the second plurality of image points; Determining the shape of the deformable membrane depending on the disparity map; The control device according to claim 14, further configured to perform the above.

16. An operating device, The finger assembly according to any one of claims 1 to 13, Inflating means operably coupled to the finger assembly, the inflating means being configured to receive a control signal and pressurize the interior of the finger assembly depending on the control signal; The control device according to claim 14 or 15, An operating device comprising the above.

Images