Rigid-flexible combined self-sensing suction cup and control method and control system thereof

Abstract

The invention relates to a rigid-flexible combined self-sensing suction cup and a control method and system thereof, and belongs to the field of robot grabbing. The suction cup comprises a suction cup shell, a self-sensing unit, a bionic microstructure contact unit and a suction cup nozzle, the self-sensing unit and the bionic microstructure contact unit are sequentially arranged on the suction cup shell in an annular structure, the suction cup nozzle is arranged in the middle of the suction cup shell, and the self-sensing unit comprises a flexible substrate layer, an interdigital electrode layer and a sensing unit array layer. The flexible substrate layer is attached to the suction cup shell, and the interdigital electrode layer is wrapped in the middle by the flexible substrate layer and the sensing unit array layer. According to the control system and the control method, the adsorption force is fitted by collecting data of the sensor on the suction cup, whether the adsorption force meets the grabbing requirement or not is judged, and if not, the air pump is dynamically regulated and controlled, and the grabbing adsorption force is adjusted. Static pressure and dynamic pressure in the grabbing process can be effectively sensed, and high adaptability and stability of the suction cup in executing the grabbing task are guaranteed.

Description

Technical Field

[0001] The present invention belongs to the field of robot grasping and relates to a rigid-flexible self-sensing suction cup and a control method and a control system thereof. Background Art

[0002] With the rapid development of industrial automation and intelligent manufacturing, research on robot end-mounted suction cups has gradually become an important direction for improving the intelligence and safety of industrial robots. In practical applications, industrial robot end-mounted suction cups are often required to perform grasping tasks in complex and dynamic environments. However, existing suction cup designs have many limitations: on the one hand, excessive suction cup hardness may cause damage to fragile objects; on the other hand, excessive hardness may cause objects to shake or fall off during grasping. In addition, traditional suction cups lack microstructures and have difficulty adapting to rough or irregular surfaces. More importantly, many suction cup systems lack integrated self-sensing functions and cannot detect the grasping status in real time, which affects the stability and safety of grasping.

[0003] In the prior art, the invention patent with publication number "CN117124351A" discloses "a sensing and execution integrated suction cup grasping mechanism", which designs a suction cup grasping mechanism for grasping fragile, large-volume and large-area target objects. It can effectively sense the deformation force and grasping force of grasping, and ensure the safety and stability during the grasping process. However, the overall skeleton of this suction cup grasping mechanism is made of flexible material. When grasping or transporting large mass objects, if it is impacted or vibrated, it may cause the object to shake or fall off. In addition, the conductive unit on the suction cup grasping mechanism is located on the side and cannot sense the normal pressure between the suction cup and the surface of the object. In addition, the bottom and skirt of the suction cup grasping mechanism have no microstructure, making it difficult to grasp objects with a certain surface roughness.

[0004] The invention patent with publication number "CN119897817A" discloses a "vacuum suction cup clamp". The vacuum suction cup clamp designed in this invention can effectively pick up, support, hold, place and release relatively bulky and / or heavy objects, such as boxes, furniture, panels and other heavy, bulky, fragile or difficult to grasp objects. However, this vacuum suction cup clamp does not have self-sensing capabilities and cannot feedback the clamping pressure of the vacuum suction cup clamp.

[0005] The invention patent with publication number "CN118622829A" discloses "Intelligent Suction Cup and Adsorption Working Method", which designs a multifunctional device that can be intelligently controlled: it can automatically determine whether the negative pressure of the suction cup needs to be reinforced based on the data of the air pressure sensor to ensure normal operation; but the air pressure sensor can only sense the overall adsorption force of the suction cup, and cannot accurately perceive the local adsorption force of the suction cup contact surface, which may pose risks when carrying fragile items.

[0006] To sum up, the current existing suction cups lack the function of local adsorption force perception, and cannot simultaneously meet the needs of overall adsorption force perception, adapting to surfaces of different roughness, and grasping large and fragile objects. When grasping objects of different roughness or large mass, their adaptability and stability also have room for improvement. Summary of the Invention

[0007] In view of this, the purpose of the present invention is to provide a rigid-flexible self-sensing suction cup and its control method and control system, which can effectively sense the static pressure and dynamic pressure during the grasping process, can grasp objects with different surface roughness or large mass objects, and ensure the high adaptability and stability of the suction cup in performing grasping tasks.

[0008] In order to achieve the above object, the present invention provides the following technical solutions:

[0009] A rigid-flexible self-sensing suction cup comprises a suction cup shell, a self-sensing unit, a bionic microstructure contact unit, and a suction cup nozzle. The self-sensing unit and the bionic microstructure contact unit are sequentially arranged in a ring structure on the suction cup shell, and the suction cup nozzle is arranged in the middle of the suction cup shell.

[0010] The self-sensing unit includes a flexible base layer, an interdigitated electrode layer, and a sensing unit array layer. The flexible base layer is adhered to the suction cup housing, and the flexible base layer and the sensing unit array layer wrap the interdigitated electrode layer in the middle.

[0011] The suction cup shell is divided into a mounting surface with several grooves and a protective surface with a smooth surface. The mounting surface of the suction cup shell includes a suction cup exhaust hole, a suction cup exhaust buffer groove, a first inner groove of the suction cup, a second inner groove of the suction cup and an outer groove of the suction cup, which are arranged in sequence from the inside to the outside; the self-sensing unit and the bionic microstructure contact unit are respectively arranged in the second inner groove of the suction cup and the outer groove of the suction cup.

[0012] Furthermore, a number of symmetrically and evenly distributed shell holes are provided in the second inner groove of the suction cup; the flexible base layer of the self-sensing unit is placed in the second inner groove of the suction cup, a flexible base groove is provided on the flexible base layer, and a number of symmetrically and evenly distributed base holes are also provided in the flexible base groove, wherein the position and number of the base holes correspond to the shell holes on the second inner groove of the suction cup, and each hole is also ensured to correspond to each other during installation.

[0013] Furthermore, the interdigitated electrode layer of the self-sensing unit is placed in the groove of the flexible substrate, wherein a plurality of interdigitated electrodes corresponding to the solder joint positions are arranged on the surface away from the bottom of the flexible substrate groove, and a plurality of symmetrically and evenly distributed solder joint positions are arranged on the surface of the bottom of the flexible substrate groove adhered to the interdigitated electrode layer, wherein the position and number of the solder joint positions and the interdigitated electrodes correspond to the substrate holes and the shell holes. During installation, each solder joint position corresponds to the substrate hole and the shell hole, and each solder joint at the solder joint position is connected to a wire, and the wire passes through the substrate hole and the shell hole and is connected to an external resistance collector.

[0014] Furthermore, the sensing unit array layer of the self-sensing unit includes a bonding layer and a sensing unit layer, and the sensing unit layer contacts the interdigitated electrode layer on the flexible base layer, wherein a number of identical sensing unit arrays are arranged in the sensing unit layer, and each sensing unit array is spaced the same distance apart; the number of sensing unit arrays is consistent with the number of interdigitated electrodes, and during installation, the gap between each two sensing unit arrays corresponds to the interdigitated electrodes of the interdigitated electrode layer.

[0015] Furthermore, the suction cup exhaust hole is used to connect the suction cup nozzle. The bottom of the suction cup nozzle is connected to the suction cup exhaust hole on the protective surface of the suction cup shell. The other end of the suction cup nozzle is connected to the external exhaust device through an air pipe to realize the extraction of air in the suction cup exhaust buffer tank in the exhaust state.

[0016] Furthermore, the suction cup suction buffer groove is used to contact the surface of the object, and form a negative pressure space with the surface of the object in the suction state to assist in grasping.

[0017] Furthermore, the first inner groove of the suction cup is used to form a flexible base groove and to form an air extraction area together with the buffer groove.

[0018] Furthermore, the bionic microstructure contact unit includes a glue base layer and a microstructure, the microstructure includes any one of a prism, a hemisphere, a pyramid, and a prism, and the size and number of the microstructure can be adjusted according to actual conditions.

[0019] Furthermore, the sensing process of the self-sensing unit is as follows: when the suction cup is working, the sensing units in the sensing unit array layer of the self-sensing unit are deformed by pressure, causing the resistance value in the interdigital electrode layer to change. The resistance collector connected to the interdigital electrode layer collects the resistance change and transmits it to the upper control system. The control system calculates the suction cup deformation based on the change in resistance value, and then reversely infers the pressure on the suction cup contact surface from the suction cup deformation, thereby obtaining the adsorption force of the self-sensing suction cup.

[0020] (1) The relationship between the change in resistance value and the degree of deformation of the suction cup is:

[0021]

[0022] Where R0 is the initial resistance of the sensing unit before the suction cup is adsorbed, ρ0 is the initial resistivity, h0 is the initial thickness of the microstructure of the sensing unit before the suction cup is adsorbed, and A0 is the initial force contact area of the sensing unit before the suction cup is adsorbed;

[0023] When the suction cup starts to absorb, the resistance value R1 is:

[0024]

[0025] Where ρ1 is the resistivity in the current state, h1 is the thickness of the sensor unit microstructure after compression after the suction cup is adsorbed, and A1 is the contact area of the sensor unit after the suction cup is adsorbed. The change in resistance value when the suction cup is working is:

[0026] ΔR=R0-R1

[0027] (2) The relationship between the suction cup deformation and the adsorption force change is:

[0028]

[0029] Where ε is the deformation of the sensing unit; Δh is the thickness of the sensing unit microstructure that changes under pressure after adsorption; the corresponding adsorption force F is calculated. s for:

[0030] F s =A1Eε=na1Eε

[0031] Where E is the Young's modulus of the microstructure of the sensing unit, n is the number of microstructures, a1 is the contact area between the microstructure prism and the mounting surface, and A1 = na1.

[0032] A control method for controlling the aforementioned rigid-flexible self-sensing suction cup is also proposed, the method comprising:

[0033] Acquiring data signals from the sensing array unit layer of the self-sensing sucker through a resistance data collector;

[0034] The acquired data signal is first preprocessed, including signal normalization, noise reduction, and time window division;

[0035] The pre-processed resistance data is input into the fitting model and then converted into adsorption force data;

[0036] Based on the calibrated upper and lower limits of the adsorption force, it is determined whether the current stress meets the grasping requirements. If so, the signal is continuously collected. If not, a control signal is generated to instruct the air pump control device to adjust the air pump operating status and control the suction cup air pressure. The air pump operating status is dynamically adjusted through real-time feedback from the pressure sensor.

[0037] A rigid-flexible self-sensing suction cup control system is also proposed, which includes a power supply, an air pump control device, an air pump, a pressure differential transmitter, a resistance collector, and a host computer, wherein the power supply is connected to the air pump control device, the air pump control device is connected to the air pump and the pressure differential transmitter through a wire, the air pump control device communicates with the computer system of the host computer, and the air pump control device is powered by an external power supply; the air pump is connected to the suction cup mouth of the self-sensing suction cup through an air pipe, the wire led out from the hole in the shell of the self-sensing suction cup is connected to the resistance collector, and the resistance collector is connected to the host computer; the host computer executes the aforementioned self-sensing suction cup control method according to the status information obtained by the resistance collector to perform feedback control on the air pump control device.

[0038] The beneficial effects of the present invention are:

[0039] The suction cup shell of the present invention is used to bear weight, resist impact and reduce vibration, thereby ensuring the stability of the suction cup during grasping and transportation. The flexible base layer is embedded in the groove at the bottom of the suction cup shell as the base layer of the sensor. The interdigitated electrode layer has four symmetrical electrodes embedded in the groove of the flexible base layer. Each electrode is led out to the suction cup shell by a wire as the sensor electrode layer. The lower layer of the sensing unit array layer is composed of four identical and paired sensing units. The center between each two sensing unit arrays is aligned one by one with the four holes of the interdigitated electrode layer, the flexible base layer, and the suction cup shell. The upper layer of the sensing unit array layer is a flexible material in contact with the surface of the object. The sensor thus constructed can not only effectively sense the static normal pressure between the surface of the object and the contact surface of the suction cup, but also its special four-sensing unit array structure can sense the dynamic pressure when the object shakes. Due to its soft characteristics, it can also effectively protect fragile grasped objects. The bionic microstructure contact unit enables the suction cup to adapt to objects with a variety of surfaces of different roughness. The self-sensing suction cup with a combination of rigidity and flexibility constructed in this way can effectively sense the static and dynamic pressures during the grasping process, and can grasp objects with different surface roughness or large mass objects, ensuring the high adaptability and stability of the suction cup in performing grasping tasks.

[0040] Other advantages, objects, and features of the present invention will be described in part in the following description and, in part, will be apparent to those skilled in the art upon examination of the following description or may be learned from practice of the present invention. The objects and other advantages of the present invention may be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below with reference to the accompanying drawings, in which:

[0042] Figure 1 Schematic diagram of the assembly of a self-sensing suction cup according to an embodiment of the present invention;

[0043] Figure 2 Schematic diagram of the structure of the mounting surface of the suction cup housing according to an embodiment of the present invention;

[0044] Figure 3 Schematic diagram of the structure of the flexible substrate layer according to an embodiment of the present invention;

[0045] Figure 4 Schematic diagram of the process of preparing a flexible substrate layer according to an embodiment of the present invention;

[0046] Figure 5 Schematic diagram of the structure of the interdigitated electrode layer according to an embodiment of the present invention, wherein: Figure 5 (a) is the surface away from the bottom of the groove of the flexible substrate, Figure 5 (b) is a surface that fits the bottom of the groove of the flexible substrate;

[0047] Figure 6 Schematic diagram of the structure of the sensor unit array layer according to an embodiment of the present invention;

[0048] Figure 7 Schematic diagram of the preparation process of the sensing unit array layer according to an embodiment of the present invention;

[0049] Figure 8 Schematic diagram of the preparation process of the bionic microstructure contact unit according to an embodiment of the present invention;

[0050] Figure 9 Schematic diagram of the structure of the mounting surface of the assembled suction cup housing according to an embodiment of the present invention;

[0051] Figure 10 This is a working adsorption diagram of a self-sensing suction cup according to another embodiment of the present invention;

[0052] Figure 11 1 is a flow chart of a self-sensing suction cup control method according to another embodiment of the present invention;

[0053] Figure 12 Schematic diagram of a flow chart of a self-sensing chuck stress-resistance data fitting method according to another embodiment of the present invention;

[0054] Figure 13 Schematic diagram of equipment connections for a self-sensing suction cup control system according to another embodiment of the present invention.

[0055] Figure markings: 1-suction cup shell; 2-flexible substrate layer; 3-interdigitated electrode layer; 4-bionic microstructure contact unit; 5-sensing unit array layer; 6-suction cup mouth; 101-shell hole, 102-suction cup exhaust hole, 103-suction cup first inner groove, 104-suction cup second inner groove, 105-suction cup outer groove; 106-exhaust buffer groove; 201-flexible substrate layer groove; 202-substrate hole; 301-interdigitated electrode, 302-welding point; 501-bonding layer; 502-sensing unit layer. DETAILED DESCRIPTION

[0056] The following describes the embodiments of the present invention by means of specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0057] Among them, the accompanying drawings are only for illustrative purposes and represent only schematic diagrams rather than actual pictures, and should not be understood as limiting the present invention. In order to better illustrate the embodiments of the present invention, some parts of the accompanying drawings may be omitted, enlarged or reduced, and do not represent the dimensions of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions may be omitted in the accompanying drawings.

[0058] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", "front", "back", etc. indicating directions or positional relationships, they are based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operate in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0059] See also Figures 1 to 13 , which is a rigid-flexible self-sensing suction cup and its grasping process, data fitting method, control method, and control system.

[0060] Example 1

[0061] This embodiment first proposes a rigid-flexible self-sensing suction cup that can effectively sense the static and dynamic pressures during the grasping process, and can grasp objects with different surface roughness or large mass objects, ensuring the high adaptability and stability of the suction cup in performing grasping tasks.

[0062] like Figure 1 The assembly diagram of a rigid-flexible self-sensing suction cup in the present embodiment shown includes: a suction cup shell 1, a self-sensing unit, a bionic microstructure contact unit 4 and a suction cup mouth 6. The self-sensing unit and the bionic microstructure contact unit 4 are arranged in sequence in a ring structure on the suction cup shell 1, and the suction cup mouth 6 is arranged in the middle of the suction cup shell 1, wherein the self-sensing unit includes a flexible base layer 2, an interdigitated electrode layer 3 and a sensing unit array layer 5. The flexible base layer 2 is adhered to the suction cup shell 1, and the flexible base layer 2 and the sensing unit array layer 5 cover the interdigitated electrode layer 3 in the middle.

[0063] More specifically, in this embodiment, the suction cup housing 1 is divided into a mounting surface with a plurality of grooves and a protective surface with a smooth surface, wherein, Figure 2 As shown, the mounting surface of the suction cup housing 1 includes a suction cup exhaust hole 102, a suction cup exhaust buffer groove 106, a suction cup first inner groove 103, a suction cup second inner groove 104 and a suction cup outer groove 105 which are arranged in sequence from the inside to the outside.

[0064] In this embodiment, the suction cup housing 1 is made of a hard material, which includes any one of ABS (acrylonitrile butadiene styrene copolymer), polyester (PET), polyvinyl chloride, polytetrafluoroethylene, polycarbonate (PC), nylon (PA), polypropylene (PP), resin material, aluminum alloy, and stainless steel.

[0065] The suction cup exhaust hole 102 is used to connect the suction cup nozzle 6. The bottom of the suction cup nozzle 6 is connected to the suction cup exhaust hole 102 on the protective surface of the suction cup shell 1. The other end of the suction cup nozzle 6 is connected to the external exhaust device through an air pipe to realize the extraction of air in the suction cup exhaust buffer tank 106 in the exhaust state.

[0066] The suction cup air extraction buffer groove 106 is used to contact the surface of the object and form a negative pressure space with the surface of the object in the air extraction state to assist in grasping.

[0067] The first inner groove 103 of the suction cup is used to form a flexible base groove and to form an air extraction area together with the buffer groove.

[0068] The second inner groove 104 of the suction cup is used to install the self-sensing unit, wherein a plurality of symmetrically and evenly distributed shell holes 101 are opened in the second inner groove 104 of the suction cup. In this embodiment, the number of the shell holes 101 is four.

[0069] The flexible base layer 2 of the self-sensing unit is placed in the second inner groove 104 of the suction cup, as shown in FIG. Figure 3 As shown, a flexible substrate groove 201 is provided on the flexible substrate layer 2, and a number of symmetrically and evenly distributed substrate holes 202 are also provided in the flexible substrate groove 201, wherein the position and number of the substrate holes 202 correspond to the outer shell holes 101 on the second inner groove 104 of the suction cup, and each hole is also ensured to correspond to each other during installation.

[0070] In this embodiment, the flexible material of the flexible base layer 2 is any one of silicone rubber, natural rubber (NR), synthetic rubber (SBR, NBR, EPDM, etc.), polyurethane (PU), chloroprene rubber (Neoprene), thermoplastic elastomer (TPE), foam rubber (Foam Rubber), and polydimethylsiloxane (PDMS).

[0071] like Figure 4 As shown, in this embodiment, using a flexible polymer substrate (PDMS) as an example, the process for preparing the flexible base layer 2 is as follows: First, assemble and secure the 3D-printed suction cup housing 1 and the inner and outer rings. Uncured liquid PDMS is introduced into the assembled mold, ensuring that the PDMS slightly covers the inner baffle. The top cover is then assembled and secured, and dried in a drying oven at 70°C. After the PDMS solidifies, the top cover and inner and outer rings are demolded to form the flexible base layer 2.

[0072] The interdigitated electrode layer 3 of the self-sensing unit is placed in the groove 201 of the flexible substrate, wherein Figure 5 in Figure 5 As shown in (a), a plurality of interdigitated electrodes 301 corresponding to the soldering points 302 are provided on the surface away from the bottom of the flexible substrate groove 201. Figure 5 in Figure 5 As shown in Figure (b), the interdigitated electrode layer 3 is attached to the surface at the bottom of the flexible substrate groove 201 and is provided with a number of symmetrically and evenly distributed solder joints 302. The positions and number of the solder joints 302 and interdigitated electrodes 301 correspond to the substrate holes 202 and the housing holes 101. During installation, each solder joint 302 corresponds to the substrate holes 202 and the housing holes 101. Each solder joint at the solder joint 302 is connected to a wire, which passes through the substrate holes 202 and the housing holes 101 and is connected to an external resistor collector. In this embodiment, the interdigitated electrode layer 3 is annular in shape, with four symmetrically and evenly distributed interdigitated electrodes 301 on the front and four corresponding solder joints 302 on the back. Each solder joint 302 has two solder joints, for a total of eight solder joints. Each solder joint is connected to a wire, which passes through the holes in the flexible groove and the suction cup housing 1.

[0073] like Figure 6As shown, the sensor unit array layer 5 of the self-sensing unit includes a bonding layer 501 and a sensor unit layer 502. The sensor unit layer 502 contacts the interdigitated electrode layer 3 on the flexible base layer. The sensor unit layer 502 is provided with a plurality of identical sensor unit arrays, and each sensor unit array is spaced the same distance apart. In this embodiment, the sensor unit array layer 5 is arranged in a ring shape, and its sensor array units are the arc segments under the ring structure. The number of sensor unit arrays is consistent with the number of interdigitated electrodes 301. During installation, the gap between each two sensor unit arrays corresponds to the interdigitated electrodes 301 of the interdigitated electrode layer 3.

[0074] In this embodiment, the bonding layer 501 of the sensing unit array layer 5 is also made of a flexible material, wherein the flexible material includes any one of silicone rubber, natural rubber (NR), synthetic rubber (SBR, NBR, EPDM, etc.), polyurethane (PU), chloroprene rubber (Neoprene), thermoplastic elastomer (TPE), foam rubber (Foam Rubber), and polydimethylsiloxane (PDMS). The sensing unit layer 502 is made of a polymer of any one of silicone rubber, natural rubber (NR), synthetic rubber (SBR, NBR, EPDM, etc.), polyurethane (PU), chloroprene rubber (Neoprene), thermoplastic elastomer (TPE), foam rubber (Foam Rubber), and polydimethylsiloxane (PDMS) and any one of carbon nanotubes, graphene, MXene, carbon fiber, carbon nanofiber, and carbon nanospheres, or any combination thereof.

[0075] In this embodiment, if Figure 7 As shown, taking the polymer flexible substrate PDMS and carbon nanomaterials CNTs as an example, the process of preparing the above-mentioned sensor unit array layer 5 is as follows: first, the prepolymer and the cross-linking agent are prepared into a PDMS solution at a ratio of 10:1 for standby use, the carbon nanotubes are mixed into the PDMS solution and stirred evenly, then the mixed solution is poured into the mold so that it just covers the microstructure of the mold, and then the mold and the mixed solution are dried and solidified. At this time, the mixed solution is in a semi-solid state, and then the PDMS solution is introduced into the mold containing the mixed solution. After the whole solution is dried and solidified, the sensor unit array layer 5 is taken out from the mold.

[0076] The outer groove 105 of the suction cup is used to mount the biomimetic microstructure contact unit 4. The biomimetic microstructure contact unit 4 includes an adhesive base layer and a microstructure. The microstructure can be any of a prism, hemisphere, pyramid, or prism. The size and number of the microstructures can be adjusted according to actual conditions. In this embodiment, the biomimetic microstructure contact unit 4 is a honeycomb.

[0077] In this embodiment, the material of the bionic microstructure contact unit 4 is any one of silicone rubber, natural rubber (NR), synthetic rubber (SBR, NBR, EPDM, etc.), polyurethane (PU), chloroprene rubber (Neoprene), thermoplastic elastomer (TPE), foam rubber (Foam Rubber), and polydimethylsiloxane (P0DMS).

[0078] like Figure 8 As shown, taking the polymer flexible substrate PDMS as an example, the process of preparing the biomimetic microstructure contact unit 4 is as follows: the prepolymer and the cross-linking agent are mixed in a ratio of 10:1 to form a PDMS solution and poured into a self-designed and 3D-printed mold. After drying and curing, the flexible substrate layer 2 is removed from the mold and finally adhered to the outer groove 105 of the suction cup with the PDMS solution.

[0079] Figure 9 The figure shows the structural schematic of the mounting surface of the suction cup housing 1 after assembly. The present invention utilizes flexible materials and carbon nanomaterials to fabricate the pressure sensor. Polydimethylsiloxane (PDMS) is preferred among flexible materials for its chemical resistance, high flexibility, and long-term stability. Carbon nanotubes are preferred among carbon nanomaterials for their excellent electrical conductivity and mechanical properties. The combination of these two materials allows the suction cup, which functions as a sensor, to possess both a wide measurement range and high sensitivity. This allows the suction cup to accurately sense the change in sensor resistance caused by the suction force during the suction process, ensuring stability when grasping the target object.

[0080] The lower layer of the sensing unit array layer 5 of the sensor manufactured by the present invention is four equally divided annular arrays. This structure can simultaneously sense the static normal pressure and dynamic pressure of the contact surface at the bottom of the suction cup, and can determine whether the suction cup is firmly adsorbed and the direction of shaking.

[0081] The shape of the sensing unit of the sensor produced by the present invention is preferably a prism-shaped microstructure, because its structure has a relatively flat contact surface and a gradually expanding shape, which can effectively disperse the applied pressure, avoid local stress concentration, and provide a larger contact area, thereby ensuring more uniform stress transfer and higher stability.

[0082] The bionic microstructure contact unit 4 produced by the present invention is adhered to the outer groove 105 of the suction cup. Its bionic honeycomb structure still has good air tightness and stability after a large deformation. The bionic microstructure contact unit 4 made of polydimethylsiloxane (PDMS) can adhere well to the rough surface, so that the suction cup can adsorb objects with different surfaces of roughness.

[0083] The suction cup made by the present invention adopts a combination of rigidity and flexibility. The suction cup shell 1 is made of hard material, preferably resin material. This material is easy to process, has good strength and rigidity, and can provide better structural support to prevent the object from shaking or falling off due to impact or vibration when grasping or carrying large mass objects; the contact surface with the object is composed of a bionic microstructure contact unit 4, a flexible base layer 2, and an upper layer of a sensor unit array layer 5. Its soft characteristics can better absorb fragile objects.

[0084] The sensing process of the self-sensing unit is as follows: when the suction cup is working, the sensing units in the sensing unit array layer of the self-sensing unit are deformed by pressure, causing the resistance value in the interdigital electrode layer to change. The resistance collector connected to the interdigital electrode layer collects the resistance change and transmits it to the upper control system. The control system calculates the suction cup deformation based on the change in resistance value, and then reversely infers the pressure on the suction cup contact surface from the suction cup deformation, thereby obtaining the adsorption force of the self-sensing suction cup.

[0085] (1) The relationship between the change in resistance value and the degree of deformation of the suction cup is:

[0086]

[0087] Where R0 is the initial resistance of the sensor unit before the suction cup is adsorbed, ρ0 is the initial resistivity, h0 is the initial thickness of the sensor unit microstructure before the suction cup is adsorbed, and A0 is the initial force contact area of the sensor unit before the suction cup is adsorbed. When the suction cup starts to adsorb, the resistance value R1 is

[0088]

[0089] Among them, ρ1 is the resistivity in the current state, h1 is the thickness of the sensor unit microstructure after compression after the suction cup is adsorbed, and A1 is the contact area of the sensor unit after the suction cup is adsorbed. Therefore, the change in resistance value when the suction cup is working is

[0090] ΔR=R0-R1

[0091] (2) The relationship between the suction cup deformation and the adsorption force change is:

[0092]

[0093] Where ε is the deformation of the sensing unit; Δh is the thickness of the sensing unit microstructure that changes under pressure after adsorption; the corresponding adsorption force F can be calculated s for

[0094] F s =A1Eε=na1Eε

[0095] Where E is the Young's modulus of the microstructure of the sensing unit, n is the number of microstructures, a1 is the contact area between the microstructure prism and the mounting surface, and A1 = na1.

[0096] The core links are: 1. Resistance change 2. Deformation 3. Adsorption force. ΔR→ε→F s .

[0097] like Figure 10 As shown, after the air pump evacuates the suction cup, the suction cup buffer groove generates negative pressure, causing the bionic microstructure contact unit at the bottom of the suction cup to deform and adhere to the rough surface; the internal sensing unit array layer is subjected to stress and deformed (the contact area between the sensing unit microstructure and the interdigitated electrode gradually increases, and the number of connections between CNTs and CNTs inside the sensing unit microstructure increases), thereby reducing the sensor resistance value; since there is a proportional relationship between the negative pressure area and the pressure area of the contact surface, the stress and pressure can be solved with each other, and the relationship between the resistance value and the pressure is fitted and then the control algorithm is used to determine whether to adjust the adsorption force; an increase in the adsorption force will cause the bionic microstructure contact unit to deform more and the pressure in the buffer groove to continue to decrease, and a decrease in the adsorption force will cause the bionic microstructure contact unit to deform less and the pressure in the buffer groove to increase.

[0098] Example 2

[0099] This embodiment provides a control method for controlling the self-sensing sucker in embodiment 1, such as Figure 11 As shown, it includes:

[0100] The collected resistance data signal is pre-processed, including signal normalization, noise reduction, and time window division, and then input into the data fitting model and converted into adsorption force data;

[0101] Based on the calibrated upper limit of adsorption force (F sMax ) and the lower limit (F sMin ) Determine whether the current stress meets the grasping requirements. If so, continue to collect signals; if not, generate a control signal to instruct the air pump control device to adjust the air pump operating status and control the suction cup air pressure; through real-time feedback from the pressure sensor, dynamically adjust the air pump working status.

[0102] Specifically, in actual operation, the process includes:

[0103] Step 1: The computer system receives the digital signal from the resistance data logger and performs a multi-stage data processing process. The preprocessing stage includes signal normalization, noise reduction, and time windowing to eliminate the effects of environmental vibration or electromagnetic interference.

[0104] Step 2: The computer inputs the preprocessed signal data into the model, which converts it into stress data and determines whether the current stress meets the gripping requirements (for example, insufficient suction force causing the object to slip, or excessive suction force causing the object to deform). If adjustment is required, the system generates a control signal using a proportional-integral-derivative (PID) control algorithm or a Q-learning-based reinforcement learning algorithm, instructing the air pump control device to adjust the air pump's operating status and control the suction cup air pressure. If no adjustment is required, the system returns to the initial data acquisition state.

[0105] Step 3: Dynamically adjust the air pump's operating status using real-time feedback from the pressure sensor. The feedback process includes: 1) The sensor collects pressure data; 2) The computer processes the data and generates control instructions; 3) The air pump control device adjusts the air pressure based on the instructions; 4) The sensor verifies the adjustment effect and updates the feedback data.

[0106] Example 3

[0107] This embodiment provides a fitting method for controlling the adsorption force and resistance value of the self-sensing suction cup in embodiment 1, such as Figure 12 As shown, it includes:

[0108] Step 1: The pressure and resistance data collected by the differential pressure transmitter and resistance collector undergo a multi-stage data processing process. The preprocessing stage includes signal normalization, noise reduction, and time windowing to eliminate the effects of environmental vibration or electromagnetic interference.

[0109] Step 2: Split the preprocessed data into a training set, a validation set, and a test set. The training set and validation set are used for model testing and verification. The input of the data set is the resistance value, and the output label information is the adsorption force. The adsorption force can be calculated by multiplying the pressure collected by the differential pressure transmitter by the area adsorbed by the suction cup.

[0110] Step 3: Build a network model such as a multi-layer perceptron (MLP), a radial basis function network (RBFN), a physical information neural network (PINN), etc. to fit the relationship between adsorption force and resistance value.

[0111] Step 4: When training is completed or verification performance reaches the best, save the model weight parameters.

[0112] Step 5: Load the saved weight parameters into the model structure and then test the model using the test set. If the model meets the performance requirements, save it for subsequent real-time inference. If not, perform data expansion or optimize the algorithm model, and repeat steps 1 to 5 until the performance indicators are met.

[0113] Example 4

[0114] This embodiment is based on the self-sensing sucker in the above embodiment 1 and the self-sensing sucker control method in the embodiment 2, and proposes a self-sensing sucker control system, wherein, Figure 13 As shown, the self-sensing suction cup control system includes a power supply, an air pump control device, an air pump, a resistance collector, and a host computer. The power supply is connected to the air pump control device, which is connected to the air pump through a wire and can communicate with the computer system of the host computer through a serial port such as RS-485 or a Wi-Fi module. The air pump control device is powered by an external power supply; the air pump is connected to the suction cup nozzle 6 of the self-sensing suction cup through an air pipe, and the wire leading out of the shell hole 101 of the self-sensing suction cup is connected to the resistance collector, which is connected to the host computer; the host computer performs feedback control on the air pump control device according to the status information obtained by the resistance collector.

[0115] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions, which should all be included in the scope of the claims of the present invention.

Claims

1. A rigid-flexible self-sensing suction cup, characterized by: The self-sensing suction cup comprises: a suction cup shell, a self-sensing unit, a bionic microstructure contact unit and a suction cup mouth. The self-sensing unit and the bionic microstructure contact unit are arranged in a ring structure on the suction cup shell in sequence. The suction cup mouth is arranged in the middle of the suction cup shell, wherein: The self-sensing unit includes a flexible base layer, an interdigitated electrode layer, and a sensing unit array layer. The flexible base layer is adhered to the suction cup housing, and the flexible base layer and the sensing unit array layer wrap the interdigitated electrode layer in the middle. The suction cup shell is divided into a mounting surface with several grooves and a protective surface with a smooth surface. The mounting surface of the suction cup shell includes a suction cup exhaust hole, a suction cup exhaust buffer groove, a first inner groove of the suction cup, a second inner groove of the suction cup and an outer groove of the suction cup, which are arranged in sequence from the inside to the outside; the self-sensing unit and the bionic microstructure contact unit are respectively arranged in the second inner groove of the suction cup and the outer groove of the suction cup.

2. The rigid-flexible self-sensing suction cup according to claim 1, characterized in that: Several symmetrically and evenly distributed shell holes are provided in the second inner groove of the suction cup; the flexible base layer of the self-sensing unit is placed in the second inner groove of the suction cup, and a flexible base groove is provided on the flexible base layer, and several symmetrically and evenly distributed base holes are also provided in the flexible base groove, wherein the position and number of the base holes correspond to the shell holes on the second inner groove of the suction cup, and each hole is also ensured to correspond to each other during installation.

3. The rigid-flexible self-sensing suction cup according to claim 2, characterized in that: The interdigitated electrode layer of the self-sensing unit is placed in the groove of the flexible substrate, wherein a number of interdigitated electrodes corresponding to the solder joints are arranged on the surface away from the bottom of the flexible substrate groove, and a number of symmetrically and evenly distributed solder joints are arranged on the surface of the interdigitated electrode layer attached to the bottom of the flexible substrate groove, wherein the position and number of the solder joints and the interdigitated electrodes correspond to the holes in the substrate and the holes in the shell. During installation, each solder joint corresponds to the hole in the substrate and the hole in the shell, and each solder joint at the solder joint is connected to a wire, which passes through the hole in the substrate and the hole in the shell and is connected to an external resistance collector.

4. The rigid-flexible self-sensing suction cup according to claim 3, characterized in that: The sensing unit array layer of the self-sensing unit includes a bonding layer and a sensing unit layer. The sensing unit layer contacts the interdigital electrode layer on the flexible base layer, wherein a number of identical sensing unit arrays are arranged in the sensing unit layer, and each sensing unit array is spaced the same distance apart; the number of sensing unit arrays is consistent with the number of interdigital electrodes. During installation, the gap between each two sensing unit arrays corresponds to the interdigital electrodes of the interdigital electrode layer.

5. The rigid-flexible self-sensing suction cup according to claim 1, characterized in that: The suction cup exhaust hole is used to connect the suction cup nozzle. The bottom of the suction cup nozzle is connected to the suction cup exhaust hole on the protective surface of the suction cup shell. The other end of the suction cup nozzle is connected to the external exhaust device through an air pipe to realize the extraction of air in the suction cup exhaust buffer tank under the exhaust state.

6. The rigid-flexible self-sensing suction cup according to claim 1, characterized in that: The suction cup's air extraction buffer groove is used to contact the surface of the object, forming a negative pressure space with the object surface in the air extraction state to assist in grasping; The first inner groove of the suction cup is used to form a flexible base groove and to form an air extraction area together with the buffer groove.

7. The rigid-flexible self-sensing suction cup according to claim 1, characterized in that: The bionic microstructure contact unit includes a glue base layer and a microstructure. The microstructure includes any one of a prism, a hemisphere, a pyramid, and a prism. The size and number of the microstructure can be adjusted according to actual conditions.

8. The rigid-flexible self-sensing suction cup according to claim 1, characterized in that: The sensing process of the self-sensing unit is as follows: when the suction cup is working, the sensing units in the sensing unit array layer of the self-sensing unit are compressed and deformed, causing the resistance value in the interdigital electrode layer to change. The resistance collector connected to the interdigital electrode layer collects the resistance change and transmits it to the upper control system. The control system calculates the suction cup deformation based on the resistance change, and then infers the pressure on the suction cup contact surface from the suction cup deformation, thereby obtaining the adsorption force of the self-sensing suction cup. (1) The relationship between the change in resistance value and the degree of deformation of the suction cup is: Where R0 is the initial resistance of the sensing unit before the suction cup is adsorbed, ρ0 is the initial resistivity, h0 is the initial thickness of the microstructure of the sensing unit before the suction cup is adsorbed, and A0 is the initial force contact area of the sensing unit before the suction cup is adsorbed; When the suction cup starts to absorb, the resistance value R1 is: Where ρ1 is the resistivity in the current state, h1 is the thickness of the sensor unit microstructure after compression after the suction cup is adsorbed, and A1 is the contact area of the sensor unit after the suction cup is adsorbed. The change in resistance value when the suction cup is working is: ΔR=R0-R1 (2) The relationship between the suction cup deformation and the adsorption force change is: Where ε is the deformation of the sensing unit; Δh is the thickness of the sensing unit microstructure that changes under pressure after adsorption; the corresponding adsorption force F is calculated. s for: F s =A1Eε=na1Eε Where E is the Young's modulus of the microstructure of the sensing unit, n is the number of microstructures, a1 is the contact area between the microstructure prism and the mounting surface, and A1 = na1.

9. A method for controlling the rigid-flexible self-sensing suction cup according to any one of claims 1 to 8, characterized in that: The method comprises: Acquiring data signals from the sensing array unit layer of the self-sensing sucker through a resistance data collector; The acquired data signal is first preprocessed, including signal normalization, noise reduction, and time window division; The pre-processed resistance data is input into the fitting model and then converted into adsorption force data; Based on the calibrated upper and lower limits of the adsorption force, it is determined whether the current stress meets the grasping requirements. If so, the signal is continuously collected. If not, a control signal is generated to instruct the air pump control device to adjust the air pump operating status and control the suction cup air pressure. The air pump operating status is dynamically adjusted through real-time feedback from the pressure sensor.

10. A rigid-flexible self-sensing suction cup control system, characterized by: The system includes a power supply, an air pump control device, an air pump, a pressure differential transmitter, a resistance collector, and a host computer, wherein the power supply is connected to the air pump control device, the air pump control device is connected to the air pump and the pressure differential transmitter through a wire, the air pump control device communicates with the computer system of the host computer, and the air pump control device is powered by an external power supply; the air pump is connected to the suction cup mouth of the self-sensing suction cup through an air pipe, the wire led out from the shell hole of the self-sensing suction cup is connected to the resistance collector, and the resistance collector is connected to the host computer; the host computer executes the self-sensing suction cup control method described in claim 9 according to the status information obtained by the resistance collector to feedback control the air pump control device.

Images