A proximity and tactile dual-mode sensing system applied to an underwater end effector

Abstract

This invention discloses a dual-modal sensing system for proximity and tactile sensing applied to underwater end effectors, belonging to the field of robot sensing technology. It includes a multi-region optical ranging unit, an array-type tactile sensing unit, and a data acquisition and processing device. The multi-region optical ranging unit houses a vertical-cavity surface-emitting laser and a single-photon avalanche diode array detector, located above an angle-adjustable substrate. The array-type tactile sensing unit contains an electrode layer and a dielectric layer. The data acquisition and processing device includes a waterproof layer, a connecting device, a data processing unit, a main control unit, a water inlet, and a base. This invention achieves spatial coupling of the sensing areas and effective connection between the proximity and tactile fields by focusing the center of the optical proximity field directly above the tactile array. It can be installed on underwater end effectors to achieve continuous underwater near-field non-contact and contact sensing, solving the problems of near-field visual perception distortion and ineffective connection of sensing information.

Description

Technical Field

[0001] This invention relates to the field of robot sensing technology, and in particular to a proximity and tactile dual-modal sensing system for underwater end effectors. Background Technology

[0002] In underwater near-field operations, end effectors need to accurately perceive distance, orientation, and surface features before contacting the target, and simultaneously acquire contact force distribution information in real time after contact to achieve precise operation. Currently, underwater robots mainly rely on sonar, underwater vision, and single-point ranging sensors for environmental perception. Although sonar systems have a long detection range, they have blind spots in the near field (within a range of several centimeters to tens of centimeters) and limited resolution, making it difficult to meet the precision operation requirements of end effectors. Underwater vision systems are severely affected by water scattering, absorption, and lighting conditions, with imaging quality dropping sharply in turbid waters or low-light environments, leading to near-field visual perception distortion. Existing laser ranging sensors mostly use single-point measurement methods, providing distance information in only one direction and failing to acquire distance distribution on the target surface, making it difficult to support the multi-dimensional perception requirements during the approach process. Furthermore, existing underwater sensing technologies generally separate proximity detection from contact detection, lacking a sensing system that integrates the two. This separation of proximity and tactile sensing not only increases the complexity of system integration but also limits the continuity of perception during the continuous operation of the end effector in the approach and contact process. Summary of the Invention

[0003] This invention provides a dual-modal sensing system for proximity and touch in underwater end effectors, which solves the problem that existing underwater end effectors lack proximity sensing capabilities in close-range operations and that proximity and contact sensing information cannot be effectively integrated in the underwater near field.

[0004] This invention has the following features:

[0005] A proximity and tactile dual-modal sensing system for underwater end effectors includes a multi-area optical ranging unit, an array-type tactile sensing unit, and a data acquisition and processing device.

[0006] The multi-region optical ranging unit incorporates a vertical-cavity surface-emitting laser (VCSEL) and a single-photon avalanche diode (SPAD) array detector, both positioned above an angle-adjustable substrate. The VCSEL emits wide-field modulated blue-green light with a wavelength of 450nm-570nm. The SPAD array detector is... The unit structure is used to receive reflected light signals of corresponding bands in partitions and acquire time distribution array data.

[0007] The array-type tactile sensing unit includes an upper electrode, a lower electrode, and a dielectric layer disposed between the upper and lower electrodes. Multiple tactile sensing units are arranged independently to form a complete array. Tactile array.

[0008] The data acquisition and processing device includes a waterproof layer, a connecting device, a data processing unit, a main control unit, a water inlet, and a base. The data processing unit is used to generate a histogram from the time distribution array data acquired by the SPAD array detector; the main control unit includes an ADC sampling module, a computing unit, and an I3C interface.

[0009] The multi-region optical ranging unit adjusts its spatial orientation through the angle-adjustable substrate, so that its proximity field center is focused directly above the array-type tactile sensing unit, thereby achieving spatial coupling between proximity sensing and tactile sensing areas.

[0010] Preferably, the dielectric layer is a porous ionogel with hydrophobic properties and deformation self-healing properties.

[0011] Preferably, the angle-adjustable substrate is placed around the tactile array, and its height does not exceed that of the tactile array.

[0012] Preferably, the data processing unit distinguishes between direct reflection signals and water backscattered signals based on the histogram generated by the time distribution array, and dynamically adjusts the VCSEL transmission power and the SPAD detection threshold.

[0013] Preferably, the operation of the dual-modal sensing system includes the following steps:

[0014] Step 1: The data processing unit performs geometric topological analysis on the tactile markers of the adjacent surface using the proximity field. Through centroid calculation, candidate neighborhood point search, and polar angle sorting of boundary markers, an ordered sequence of markers is generated. Based on the index correspondence, each proximity field is established to generate a standard proximity field. The calculation formula is as follows:

[0015] (1)

[0016] (2)

[0017] (3)

[0018] in, The coordinates of the tactile marker point, Using the centroid coordinates, This represents the number of unsorted markers. The coordinates of the candidate neighboring points, The coordinates of the sorted marked points. The nearest distance from a candidate neighboring point to a sorted labeled point. The polar angle of the boundary marker point relative to the centroid.

[0019] Step Two: Multiple optical ranging units collect spatial distribution information of the target area and jointly generate a proximity point cloud; the displacement of marker points is used to determine whether contact has occurred, and the displacement is compared with a preset threshold to identify the tactile point cloud. An iterative nearest-point method is used to align the standard proximity field with the self-tactile field, the expression of which is:

[0020] (4)

[0021] in, and These represent the rotation matrix and translation vector, respectively. Indicates the contact area of ​​itself Marker points; Indicates its position in the standard proximity field The corresponding point cloud coordinates, This represents a three-dimensional mapping function.

[0022] Step 3: If the standard proximity field is determined to be aligned with the tactile field, the dual-modal sensing data is transmitted to the terminal in real time via the I3C interface; otherwise, the process is repeated until alignment is achieved.

[0023] The technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

[0024] (1) The medium layer of the array-type tactile unit is made of porous ion gel, which has hydrophobic properties and deformation self-recovery performance, and is suitable for repeated contact and impact scenarios under still water conditions; the master-slave control unit ensures low-latency transmission of dual-modal data, and the I3C communication protocol meets the scalability requirements of integration into underwater end effectors.

[0025] (2) Using 450nm-570nm blue-green modulated light waves, the SPAD array detector is used to obtain the time distribution array and generate a histogram, which effectively distinguishes the direct reflection signal from the backscattered signal of the water body and dynamically adjusts the detection parameters; at the same time, based on the iterative topology matching of centroid, nearest neighbor distance and polar angle sorting, feature ambiguity caused by underwater background texture blurring is avoided, and reliable proximity field generation is achieved.

[0026] (3) By focusing the center of the optical proximity field onto the tactile array directly above the substrate with an adjustable angle, and combining geometric topology analysis to adaptively generate ordered marker points that are aligned with the tactile field, the problem of the proximity field and contact field sensing information of the underwater end effector cannot be effectively connected in close-range operation is solved. Attached Figure Description

[0027] Figure 1 These are external and internal structural diagrams of embodiments of the present invention;

[0028] Figure 2 This is a schematic diagram of the underwater two-fingered claw integrated in an embodiment of the present invention;

[0029] Figure 3 This is a schematic diagram of an underwater grasping experiment in an embodiment of the present invention;

[0030] Figure 4 This is a flowchart illustrating a process in an embodiment of the present invention;

[0031] Among them, 11-multi-area optical ranging unit, 12-angle adjustable substrate, 21-flexible water-permeable film, 22-array tactile sensing unit, 31-waterproof layer, 32-connection device, 33-data processing unit, 34-main control unit, 35-water inlet, and 36-base. Detailed Implementation

[0032] This invention provides a dual-modal sensing system for proximity and touch in underwater end effectors, solving the problems of lack of proximity sensing capability in close-range operations and the inability to effectively integrate proximity and contact sensing information in the underwater near-field. The detailed description of this invention is provided to enable those skilled in the art to implement it.

[0033] like Figure 1 As shown, a proximity and tactile dual-modal sensing system for underwater end effectors includes a multi-area optical ranging unit 11, an array-type tactile sensing unit 21, and a data acquisition and processing device.

[0034] The multi-region optical ranging unit 11 includes a vertical-cavity surface-emitting laser (VCSEL) and a single-photon avalanche diode (SPAD) array detector, both positioned above an angle-adjustable substrate 12. The VCSEL emits wide-field modulated blue-green light with a wavelength of 450nm-570nm. The SPAD array detector is... The unit structure is used to receive reflected light signals of corresponding bands in partitions and acquire time distribution array data.

[0035] The array-type tactile sensing unit 22 includes an upper electrode, a lower electrode, and a dielectric layer disposed between the upper and lower electrodes. Multiple tactile sensing units are arranged independently to form a complete array. Tactile array.

[0036] The data acquisition and processing device includes a waterproof layer 31, a connecting device 32, a data processing unit 33, a main control unit 34, a water inlet 35, and a base 36. The data processing unit 33 is used to generate a histogram from the time distribution array data acquired by the SPAD array detector; the main control unit 34 includes an ADC sampling module, a computing unit, and an I3C interface.

[0037] The multi-region optical ranging unit adjusts its spatial orientation through the angle-adjustable substrate 12, so that its proximity field center is focused directly above the array-type tactile sensing unit 22, thereby achieving spatial coupling between proximity sensing and tactile sensing areas.

[0038] Preferably, the dielectric layer is a porous ionogel with hydrophobic properties and deformation self-healing properties.

[0039] Preferably, the angle-adjustable substrate 12 is placed around the tactile array, and its height does not exceed that of the tactile array.

[0040] Preferably, the data processing unit distinguishes between direct reflection signals and water backscattered signals based on the histogram generated by the time distribution array, and dynamically adjusts the VCSEL transmission power and the SPAD detection threshold.

[0041] like Figure 2 , Figure 3 and Figure 4 As shown, the operation of the dual-modal sensing system includes the following steps:

[0042] Step 1: Integrate the present invention into the end of the underwater parallel two-finger claw, and open and initialize the parameters.

[0043] Step 2: Data processing unit 33 performs geometric topological analysis using tactile markers on the adjacent surfaces of the proximity field. Through centroid calculation, candidate neighborhood point search, and polar angle sorting of boundary markers, it generates ordered marker sequence sequences and establishes each proximity field according to the index correspondence to generate a standard proximity field. The calculation formula is as follows:

[0044] (1)

[0045] (2)

[0046] (3)

[0047] in, The coordinates of the tactile marker point, Using the centroid coordinates, This represents the number of unsorted markers. The coordinates of the candidate neighboring points, The coordinates of the sorted marked points. The nearest distance from a candidate neighboring point to a sorted labeled point. The polar angle of the boundary marker point relative to the centroid.

[0048] Step 3: The optical ranging unit collects spatial distribution information of the target area to jointly generate a standard proximity point cloud; and uses the displacement of event-triggered marker points to determine whether contact has occurred, comparing the displacement with a preset threshold to identify its own tactile point cloud. Then, the iterative nearest point method is used to align the standard proximity field with its own tactile field, the expression of which is:

[0049] (4)

[0050] in, and These represent the rotation matrix and translation vector, respectively. Indicates the contact area of ​​itself Marker points; Indicates its position in the standard proximity field The corresponding point cloud coordinates, This represents a three-dimensional mapping function.

[0051] Step 4: If the standard proximity field is determined to be aligned with the tactile field, the dual-modal sensing data is transmitted to the terminal in real time via the I3C interface; otherwise, the process is repeated until alignment is achieved.

[0052] Step 5: Use the two-finger gripper to pick up the object and place it in the correct place.

[0053] Unlike existing underwater near-field operation scenarios that rely solely on sonar and visual perception, this invention introduces an approach field using 450nm-570nm blue-green modulated light waves and a contact field using porous ion gel in its underwater end effector. This enables a continuous sensing flow to prevent near-field sensing blind spots and distortion risks.

[0054] The present invention can adaptively generate near-field markers by using tactile markers on the opposite surface and align them with the tactile field, thereby achieving effective connection between the proximity field and contact field sensing information in underwater close-range operations.

[0055] This invention features a structure that is resistant to static water pressure, detachable, easy to integrate, and has the characteristics of extreme data transmission.

[0056] The specific embodiments of the present invention have been described in detail above, but they are only examples.

[0057] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A proximity and tactile dual-modal sensing system for underwater end effectors, characterized in that: Includes a multi-area optical ranging unit, an array-type tactile sensing unit, and a data acquisition and processing device; The multi-region optical ranging unit includes a vertical-cavity surface-emitting laser (VCSEL) and a single-photon avalanche diode (SPAD) array detector, both positioned above an angle-adjustable substrate. The VCSEL emits wide-field modulated blue-green light with a wavelength of 450nm-570nm. The SPAD array detector is... The unit structure is used to receive reflected light signals in corresponding bands in partitions and acquire time distribution array data; The array-type tactile sensing unit includes an upper electrode, a lower electrode, and a dielectric layer disposed between the upper and lower electrodes; multiple tactile sensing units are arranged independently to form a complete array. Tactile array; The data acquisition and processing device includes a waterproof layer, a connecting device, a data processing unit, a main control unit, a water inlet, and a base; the data processing unit is used to generate a histogram from the time distribution array data acquired by the SPAD array detector; the main control unit includes an ADC sampling module, a computing unit, and an I3C interface. The multi-region optical ranging unit adjusts its spatial orientation through the angle-adjustable substrate, so that its proximity field center is focused directly above the array-type tactile sensing unit, thereby achieving spatial coupling between proximity sensing and tactile sensing areas. When the proximity and tactile dual-modal sensing system is in operation, it includes the following steps: Step 1: The data processing unit performs geometric topological analysis on the tactile markers of the proximity field's opposing surface. Through centroid calculation, candidate neighborhood point search, and polar angle sorting of boundary markers, it generates ordered marker sequence sequences for each field. Based on the index correspondence, it calibrates each proximity field to generate a standard proximity field, the calculation of which is expressed as follows: Formula 1: Formula 2: Formula 3: in, The coordinates of the tactile marker point, Using the centroid coordinates, This represents the number of unsorted markers. The coordinates of the candidate neighboring points, The coordinates of the sorted marked points. The nearest distance from a candidate neighboring point to a sorted labeled point. The polar angle of the boundary marker point relative to the centroid; Step 2: The optical ranging unit collects spatial distribution information of the target area to jointly generate a proximity point cloud; the displacement of the marker points is used to determine whether contact has occurred, and the displacement is compared with a preset threshold to identify the tactile point cloud; then, the iterative nearest point method is used to align the standard proximity field with its own tactile field, that is: Formula 4: in, and These represent the rotation matrix and translation vector, respectively. Indicates the contact area of ​​itself Marker points; Indicates its position in the standard proximity field The corresponding point cloud coordinates, Represents a three-dimensional mapping function; Step 3: If the standard proximity field is determined to be aligned with the tactile field, the dual-modal sensing data is transmitted to the terminal in real time via the I3C interface; otherwise, the process is repeated until alignment is achieved.

2. The proximity and tactile dual-modal sensing system for an underwater end effector according to claim 1, characterized in that: The dielectric layer is a porous ionogel with hydrophobic properties and deformation self-healing properties.

3. The proximity and tactile dual-modal sensing system for underwater end effectors according to claim 1, characterized in that: The angle-adjustable substrate is placed around the tactile array, and its height does not exceed that of the tactile array.

4. The proximity and tactile dual-modal sensing system for an underwater end effector according to claim 1, characterized in that: The data processing unit distinguishes between direct reflection signals and water backscattered signals based on the histogram, and dynamically adjusts the transmission power of the VCSEL and the detection threshold of the SPAD.

Images