Intelligent flexible gripper with multimodal sensing capability and intelligent grasping method thereof

Abstract

The present invention discloses an intelligent flexible gripper with multimodal sensing capability and an intelligent grasping method thereof. The top surface of the flexible base is open, and the flexible gripper is connected to the opening on the top surface of the base through a flexible actuator. There is a proximity sensor at the bottom of the base; when the proximity sensor detects the target object, it automatically triggers the heating electrode in the flexible actuator to work, causing the flexible actuator to heat up and produce bending deformation, and drive the flexible gripper to bend and perform a grasping action. At the same time, the temperature sensing electrode and strain sensing electrode signals are collected and the real-time temperature and bending angle are calculated, and the power of the heating electrode is adaptively controlled to adjust the deformation degree of the flexible gripper to achieve closed-loop control and intelligent grasping and releasing functions of the device. The present invention greatly improves the integration and intelligence of the device by integrating actuation and multimodal sensing functions, overcomes the problem that traditional soft actuator devices cannot be adaptively adjusted, and is expected to be better applied in the field of intelligent perception and driving.

Description

Technical Field

[0001] The present invention relates to an intelligent flexible gripper with multimodal sensing capability and a preparation method thereof, and in particular to an intelligent flexible gripper with proximity, temperature and strain sensing capability and rapid actuation capability and an intelligent grasping method thereof. Background Art

[0002] Living organisms can be viewed as a collaborative system of flexible sensors and soft actuators. Their unique ability to both perceive environmental information and respond to external stimuli and execute actions is highly adaptive, providing insights into the design of intelligent soft devices. Research on intelligent soft devices that integrate both perception and execution is key to achieving this biomimetic intelligence. However, current intelligent soft devices, such as soft grippers and soft robots, mostly possess execution capabilities but lack perception. To impart perception, a common strategy involves attaching or embedding separately developed flexible sensors onto existing soft actuators. However, this introduces issues such as interfacial adhesion and poor conformality. The range mismatch caused by modulus mismatch can also significantly impact device performance. Furthermore, the sensing signal is relatively monotonous, with significant crosstalk, making multimodal sensing difficult to achieve. Furthermore, existing soft actuators are generally bulky and slow to respond, making them particularly challenging to miniaturize, integrate, and remotely control. Therefore, research on intelligent soft devices with both multimodal sensing and fast execution capabilities is of great significance, yet still faces significant challenges. Summary of the Invention

[0003] In order to solve the problems existing in the background technology, the purpose of the present invention is to provide an intelligent flexible gripper with multimodal sensing capabilities and an intelligent grasping method thereof.

[0004] By integrating actuation and multimodal sensing functions, the present invention greatly improves the integration and intelligence of the device, overcomes the problem that traditional soft actuator devices cannot perform adaptive adjustment, and is expected to be better applied in the field of intelligent perception and driving.

[0005] The object of the present invention is achieved through the following technical solutions:

[0006] 1. An intelligent flexible gripper with multimodal sensing capabilities:

[0007] It includes a flexible base, a flexible clamp, a flexible actuator and a proximity sensor; a cavity is provided inside the flexible base, the top surface of the cavity is opened to face the grasped object, and multiple flexible clamps are arranged around the opening on the top surface of the flexible base. The bottom of the flexible clamp is swingably and rotatably connected to the edge of the opening on the top surface of the flexible base through a flexible actuator. The bottom of the flexible clamp is connected to the edge of the opening on the top surface of the flexible base through a flexible actuator. When the flexible actuator bends and deforms, it can drive the flexible clamp to close inward. A proximity sensor is provided at the bottom of the flexible base for detecting whether the grasped object enters the inner cavity of the flexible base opening.

[0008] One end of the flexible actuator is connected to the flexible clamping claw, and the other end of the flexible actuator is connected to the edge of the opening on the top surface of the flexible base.

[0009] The top opening of the flexible base is set to a square, and a flexible clamping claw is connected to each side of the square. The four flexible clamping claws are all isosceles triangles, and form a pyramid shape when the four flexible clamping claws are closed toward the opening and cover the opening.

[0010] The flexible actuator is embedded with strain sensing electrodes and temperature sensing electrodes, which are used to detect the temperature and stress / bending angle of the flexible actuator during bending deformation.

[0011] The flexible actuator is mainly composed of two layers of flexible films, an inner layer and an outer layer, and a heating electrode located between the two layers of flexible films; the thermal expansion coefficients of the two layers of flexible film materials are different, and the thermal expansion coefficient of the flexible film layer close to the center of the opening on the top surface of the flexible base is lower than that of the flexible film layer far from the center of the opening on the top surface of the flexible base.

[0012] The proximity sensor includes a transmitting component located on one side and a receiving component located on the other symmetrical side; the transmitting component includes an LED light source and a light source circuit board, the light source circuit board is provided with an LED light source, and the LED light source is arranged toward the receiving component for emitting a light beam; the receiving component includes a photodetector and a detector circuit board, the detector circuit board is provided with a photodetector, and the photodetector is arranged toward the transmitting component for receiving a light beam.

[0013] The proximity sensor is configured as a capacitive proximity sensor, which is electrically connected to an external signal acquisition and processing system via a wire.

[0014] The intelligent flexible gripper of the present invention can be used to intelligently grasp fragile objects, soft objects, or living things, such as insects.

[0015] The innovation of the present invention lies in the embedded arrangement of strain sensing electrodes and temperature sensing electrodes in the flexible actuator of the gripper, which detects the matching degree through real-time detection of temperature and stress, and then makes intelligent judgment and control on the grasping status of the grasped object.

[0016] 2. An intelligent grasping method of an intelligent flexible gripper:

[0017] When the intelligent flexible gripper is working, a proximity sensor is used to detect in real time whether the target object of the gripping object enters the flexible base cavity. When the gripping object is detected in real time, the heating electrode in the flexible actuator is controlled to operate, so that the flexible film is heated. The different thermal expansion coefficients of the two layers of flexible film cause the flexible actuator to bend toward the center of the flexible base opening and drive the flexible gripper to bend and perform a gripping action.

[0018] By collecting the electrical signals of the strain sensing electrodes and the temperature sensing electrodes and calculating the real-time temperature and bending angle of the intelligent flexible gripper, the power of the heating electrode in the flexible actuator is adaptively controlled according to the real-time temperature and bending angle to adjust the grasping action and deformation degree of the flexible gripper, thereby realizing closed-loop control and intelligent grasping and releasing functions of the intelligent flexible gripper.

[0019] The proximity sensor detects whether the distance between the target object of the grasping object and the bottom surface of the flexible base of the intelligent flexible gripper reaches a preset distance threshold, thereby determining whether the target object of the grasping object enters the flexible base cavity.

[0020] The flexible actuator and the flexible gripper have a pre-fixed matching relationship curve between the temperature and the bending angle during deformation. When the real-time detected temperature and the bending angle do not match on the relationship curve, adaptive feedback control increases or decreases the heating power of the heating electrode in the flexible actuator, driving the flexible gripper away from the opening of the flexible base and adjusting the grasping state. If the temperature and the bending angle still cannot match on the relationship curve, it is determined that the grasping object is not suitable for grasping, heating is stopped, and the target object is released.

[0021] When the temperature and bending angle detected in real time match on the relationship curve, the adaptive feedback control maintains the heating power of the heating electrode in the flexible actuator, driving the flexible gripper to maintain the gripping state of the gripping object.

[0022] The beneficial effects of the present invention are:

[0023] The present invention integrates a flexible actuator and a multimodal sensor in a flexible gripper, utilizes the multimodal sensor to collaboratively sense and feedback the actuation effect, realizes perception-adaptive adjustment of the drive, and achieves actuation-perception integration, thereby improving the integration, intelligence and functionality of the device.

[0024] By detecting the distance to the target object and triggering the grasping task, the grasping efficiency of the flexible gripper can be greatly improved.

[0025] With the help of temperature and strain sensors to judge the grasping state and target size, adaptive intelligent grasping of the flexible gripper can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the structure of an intelligent flexible gripper with multimodal sensing capabilities;

[0027] Figure 2 Schematic diagram of the structure of a flexible actuator having temperature sensing electrodes and strain sensing electrodes;

[0028] Figure 3 is a schematic top view of a base cavity with an optical proximity sensor;

[0029] Figure 4 is a graph showing the rate of change of resistance of the temperature sensing electrode versus temperature;

[0030] Figure 5 is a graph showing the resistance change rate of the strain sensing electrode versus bending angle;

[0031] Figure 6 Schematic diagram of a top view of a base cavity with a capacitive proximity sensor.

[0032] In the figure, 1-flexible base, 2-flexible clamp, 3-strain sensing electrode, 4-temperature sensing electrode, 5-flexible actuator, 501-PE flexible film, 502-PI flexible film, 503-heating electrode, 6-wire, 7-proximity sensor, 701-LED light source, 702-light source circuit board, 703-photodetector, 704-detector circuit board, 705-capacitive proximity sensor. DETAILED DESCRIPTION

[0033] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] like Figure 1 As shown, it includes a flexible base 1, a flexible clamp 2, a flexible actuator 5 and a proximity sensor 7; the top surface opening of the flexible base 1 is used to face the grasped object, and a plurality of flexible clamps 2 are arranged around the opening of the top surface of the flexible base 1. The bottom of the flexible clamp 2 is connected to the edge of the opening of the top surface of the flexible base 1 through the flexible actuator 5. When the flexible actuator 5 is bent and deformed, it can drive the flexible clamp 2 to close inward. A proximity sensor 7 is provided in the flexible base 1 for detecting whether the grasped object enters the cavity of the flexible base 1. The flexible actuator 5 and the proximity sensor 7 are connected to an external signal acquisition and processing system via a wire 6.

[0035] After the proximity sensor 7 detects that the grasped object enters the cavity of the flexible base 1, each flexible clamping claw 2 closes inward and covers the opening, so that the grasped object is enclosed in the cavity formed by each flexible clamping claw 2 and the flexible base 1.

[0036] One end of the flexible actuator 5 is connected to the flexible clamping claw 2 , and the other end is connected to the edge of the top opening of the flexible base 1 , so that the flexible clamping claw 2 and the top opening of the flexible base 1 are not directly connected.

[0037] like Figure 1 As shown, the top opening of the flexible base 1 is set to a square, and a flexible clamping claw 2 is connected to each of the four sides of the square. The four flexible clamping claws 2 have the same structural size and are all isosceles triangles. When the four flexible clamping claws 2 are closed into the opening and cover the opening, a pyramid shape is formed.

[0038] like Figure 2 As shown, the flexible actuator 5 is embedded with strain sensing electrodes 3 and temperature sensing electrodes 4. These electrodes are used to detect the temperature and stress of the flexible actuator 5 during bending deformation, thereby providing feedback control over the deformation of the flexible actuator 5. The strain sensing electrodes 3 and temperature sensing electrodes 4 can be connected to an external signal acquisition and processing system via wires 6.

[0039] like Figure 2 As shown, the flexible actuator 5 primarily consists of two inner and outer flexible film layers 501 and 502, and a heating electrode 503 located between the two layers. The heating electrode 503 can also be connected to an external signal acquisition and processing system via a wire 6. Strain sensing electrodes 3 and temperature sensing electrodes 4 are arranged on the surface of the flexible film 501. The flexible actuator consists of a heating electrode and two layers of flexible films with different thermal expansion coefficients. The temperature sensing electrode and strain sensing electrode are integrated into the flexible actuator, and the proximity sensor is located in the cavity of the flexible base opening.

[0040] In a specific implementation, the two flexible films 501 and 502 have different thermal expansion coefficients. The flexible film 502 near the center of the top opening of the flexible base 1 has a lower thermal expansion coefficient than the flexible film 501 far from the center of the top opening of the flexible base 1 .

[0041] like Figure 3As shown, the proximity sensor 7 includes a transmitting component located on one side of the flexible base 1 and a receiving component located symmetrically on the other side of the flexible base 1; the transmitting component includes an LED light source 701 and a light source circuit board 702, the light source circuit board 702 is provided with an LED light source 701, and the LED light source 701 is arranged toward the receiving component for emitting a light beam; the receiving component includes a photodetector 703 and a detector circuit board 704, the detector circuit board 704 is provided with a photodetector 703, and the photodetector 703 is arranged toward the transmitting component for receiving a light beam.

[0042] The LED light source 701 and the photodetector 703 are connected to an external signal acquisition and processing system via a wire 6 after passing through a light source circuit board 702 and a detector circuit board 704 respectively.

[0043] Or as Figure 6 As shown, the proximity sensor 7 is configured as a capacitive proximity sensor 705 , and the capacitive proximity sensor 705 is connected to an external signal acquisition and processing system via a wire 6 .

[0044] In a specific implementation, the signal acquisition and processing system ultimately controls the LED light source 701 to work in real time, collects the electrical signal of the photodetector 703 of the proximity sensor 7 or the capacitance signal of the capacitive proximity sensor 705, and when it is detected that the grasped object enters the flexible base 1, the feedback control heats the heating electrode 503 of the flexible actuator 5, drives the flexible clamping claw 2 to open and close toward the flexible base 1, and grasps. During the grasping process, the electrical signals of the strain sensing electrode 3 and the temperature sensing electrode 4 are collected in real time and the temperature and bending angle are calculated. There is a pre-fixed matching relationship curve between the temperature and the bending angle of the flexible actuator 5 and the flexible clamping claw 2 during deformation. When the real-time detected temperature and bending angle do not match on the relationship curve, the adaptive feedback control increases or decreases the heating power of the heating electrode 503 in the flexible actuator 5, drives the flexible clamping claw 2 to close or open toward the flexible base 1, and adjusts the grasping state. If the temperature and bending angle on the relationship curve still cannot match, it is determined that the grasped object is not suitable for grasping, and heating is stopped and the target object is released.

[0045] When the real-time detected temperature and bending angle match on the relationship curve, adaptive feedback control maintains the heating power of the heating electrode 503 in the flexible actuator 5, driving the flexible gripper 2 to maintain the gripping state of the grasped object. When the intelligent flexible gripper device is in operation, the proximity sensor 7 detects in real time whether the grasped object enters the opening of the flexible base 1. When the grasped object enters the cavity of the flexible base 1, the control triggers the heating electrode 503 in the flexible actuator 5 to operate and heat the flexible actuator 5. Due to the different thermal expansion coefficients of the two layers of flexible films in the flexible actuator 5, the flexible actuator 5 bends and deforms toward the center of the opening of the flexible base 1, driving the flexible gripper 2 to bend and grasp.

[0046] The signal acquisition and processing system collects electrical signals from the strain sensing electrodes 3 and temperature sensing electrodes 4 and calculates the real-time temperature and bending angle of the intelligent flexible gripper. Based on these real-time temperature and bending angle, it adaptively controls the power of the heating electrode 503 in the flexible actuator 5 to adjust the gripping action and deformation of the flexible gripper 2, thus achieving closed-loop control and intelligent pick-and-release functionality. The bending angle of the intelligent flexible gripper is calculated by converting the stress detected by the strain sensing electrodes 3.

[0047] Specifically, the proximity sensor 7 detects whether the distance between the grasped object and the bottom surface of the flexible base 1 of the intelligent flexible gripper reaches a preset distance threshold, and then determines whether the grasped object enters the opening of the flexible base 1.

[0048] Predefined matching curves exist between the resistance change rate of the strain sensing electrode 3 and the bending angle, and between the resistance change rate of the temperature sensing electrode 4 and the temperature. These curves enable the setting of corresponding preset bending angle and temperature thresholds in the signal acquisition and processing system. As the flexible actuator 5 and flexible gripper 2 deform, the signal acquisition and processing system calculates the bending angle and temperature based on the real-time resistance signals collected.

[0049] When the real-time temperature of the temperature sensing electrode 4 reaches the preset temperature threshold and the measured bending angle of the strain sensing electrode 3 reaches the preset bending angle threshold, the heating power of the heating electrode 503 in the flexible actuator 5 is adaptively maintained by feedback control, indicating that the grasping state of the grasping object is achieved.

[0050] When the real-time temperature of the temperature sensing electrode 4 reaches the preset temperature threshold, but the measured bending angle of the strain sensing electrode 3 is lower than the preset bending angle threshold, the heating power of the heating electrode 503 in the flexible actuator 5 is further increased to intelligently adjust the grasping action.

[0051] When the heating power increases, the measured temperature is greater than the preset temperature threshold, and the measured bending angle increases to the preset bending angle threshold, indicating that the device successfully achieves grasping after intelligently adjusting the grasping action.

[0052] When the heating power increases, the measured temperature is greater than the preset temperature threshold, but the measured bending angle is always lower than the preset bending angle threshold, indicating that the size of the grasped object is too large and not suitable for grasping. In this case, it is necessary to remove the heating power of the heating electrode 503 in the flexible actuator 5 through feedback control to avoid burning the device and release the grasping action.

[0053] In a specific implementation, the intelligent flexible gripper with multimodal sensing capability is prepared as follows:

[0054] A) Preparation of strain sensing electrodes and temperature sensing electrodes

[0055] A 30-100 nm thick metal film of Au, Ag, or other materials is deposited on the surface of a 50-200 μm thick film with a high thermal expansion coefficient, such as polyethylene (PE), PDMS, or PP. Patterned metal electrodes are then formed using a mask and laser etching techniques. The film is then pre-stretched to a certain strain, inducing a through-crack to create a strain-sensing electrode.

[0056] The area close to the strain sensing electrode was subjected to plasma surface modification treatment, and then evenly coated with PEDOT:PSS, RGO, etc. After curing at room temperature for 12 hours, a patterned temperature sensing electrode was prepared using processes such as laser etching.

[0057] B) Preparation of flexible actuators

[0058] A heating electrode was prepared on the other side of the strain and temperature sensing electrodes by screen printing. After curing at room temperature for 12 hours, conductive silver paste was used to bond wires from the pin positions of the strain sensing electrode, temperature sensing electrode and heating electrode and lead them out. Subsequently, the film prepared with the temperature sensing electrode, strain sensing electrode and heating electrode was placed in a heating furnace and kept warm at 50°C for 2 hours. After cooling, it was taken out and a flexible polyimide PI layer with a low thermal expansion coefficient and a thickness of 20-50 um was covered on the surface of the heating electrode to prepare a flexible actuator with integrated temperature sensing electrode and strain sensing electrode.

[0059] C) Assembly

[0060] A flexible actuator with integrated temperature sensing electrodes and strain sensing electrodes is assembled with a flexible base and a flexible clamp, and the wires leading from each electrode are connected to a signal acquisition and processing system to achieve multi-channel voltage output for driving and multi-channel independent resistance signal acquisition for temperature sensing and strain sensing.

[0061] The proximity sensor is integrated into the flexible base. For the proximity sensor based on optical principles, the LED light source and the photodetector are assembled on the side of the base cavity of the flexible base.

[0062] For proximity sensors based on electrical principles, metal films such as Au and Ag with a thickness of 30-100 nm are prepared on thin films such as PET and PI. With the help of mask plates, laser etching and other processes, interdigitated electrodes are obtained and assembled on the bottom surface of the base cavity of the flexible base for detecting capacitance.

[0063] The embodiments of the present invention are as follows: Example 1:

[0064] The following Figures 1 to 5 The illustrated embodiment is taken as an example to illustrate the structure of the intelligent flexible gripper with multimodal sensing capability and the intelligent grasping method thereof of the present invention.

[0065] A 30 nm thick Au metal film was deposited on a 100 μm thick polyethylene (PE) film 501 using electron beam evaporation. A patterned gold electrode was then formed using a mask. The film was pre-stretched to a certain strain to induce a through-crack, creating a strain sensing electrode 3. The area immediately adjacent to the strain sensing electrode was plasma-modified and then uniformly coated with the conductive polymer PEDOT:PSS. After curing at room temperature for 12 hours, a patterned PEDOT:PSS temperature sensing electrode 4 was fabricated using laser etching. On the other side of the strain and temperature sensing electrodes, a heating silver electrode 503 was prepared by screen printing. After curing at room temperature for 12 hours, a conductive silver paste was used to bond a wire 6 from the pin positions of the gold film, PEDOT:PSS and the heating silver electrode and lead out. Subsequently, the film prepared with the strain sensing electrode 3, the temperature sensing electrode 4 and the heating silver electrode 503 was placed in a heating furnace and kept at 50°C for 2 hours. After cooling, it was taken out and a layer of polyimide (PI) flexible layer 502 with a low thermal expansion coefficient and a thickness of 30 μm was covered on the surface of the heating silver electrode 503 to prepare a flexible actuator 5 integrated with a temperature sensing electrode and a strain sensing electrode. Figure 2 The relationship curve between the resistance change rate of the temperature sensing electrode 4 and the temperature is shown in FIG. Figure 4 As shown, the relationship curve between the resistance change rate of the strain sensing electrode 3 and the bending angle is as follows: Figure 5 According to the relationship curve, corresponding preset temperature thresholds and preset bending angle thresholds can be set in the signal acquisition and processing system.

[0066] The four flexible actuators 5 integrated with the strain sensing electrodes 3 and the temperature sensing electrodes 4 are assembled together with the flexible base 1 and the flexible gripper 2, as shown in FIG. Figure 1 As shown, the wires 6 from each electrode are connected to the signal acquisition and processing system to achieve 4-way voltage output for driving and 8-way independent resistance signal acquisition for temperature sensing and strain sensing. The proximity sensor based on optical principle is assembled in the flexible base 1, as shown in FIG. Figure 3 As shown, the transmitting assembly includes an LED light source 701 and a light source circuit board 702 mounted on one side of the flexible base 1. The receiving assembly, located on the other side, includes a photodetector 703 and a corresponding circuit board 704. The LED light source 701 is arranged toward the receiving assembly for transmitting a light beam, and the photodetector 703 is arranged toward the transmitting assembly for receiving a light beam. The transmitting assembly is led out via a wire 6 for driving the light source, and the receiving assembly is led out via a wire 6 for signal acquisition.

[0067] When the device is operating, light emitted by the LED light source 701 in the optical proximity sensor propagates within the cavity of the flexible base 1 and is received by the photodetector 703, which detects the photoelectric signal. When the grasped object appears in the light plane, the light is blocked by the grasped object, causing the photoelectric signal detected by the photodetector to drop. At this time, it is determined that the distance between the grasped object and the flexible base 1 has reached a threshold, and the heating silver electrode 503 in the flexible actuator 5 is automatically triggered to operate, causing the flexible actuator 5 to heat up. Due to the different thermal expansion coefficients of the two flexible films of PE and PI, the flexible actuator 5 bends toward the center of the opening of the flexible base 1 and drives the flexible gripper 2 to bend and grasp. At the same time, the signal acquisition and processing system collects the resistance signals of the temperature sensing electrode 4 and the strain sensing electrode 3, calculates the real-time temperature and bending angle of the device, and determines the relationship between the real-time temperature and bending angle and the temperature threshold and bending angle threshold preset in the signal acquisition and processing system. The heating power of the heating electrode 503 in the flexible actuator 5 is adaptively controlled to adjust the deformation degree of the flexible gripper 2, realizing the closed-loop control and intelligent grasping and releasing function of the device. The specific adaptive control steps are as follows:

[0068] If the measured temperature of the temperature sensing electrode 4 is lower than the preset temperature threshold, it indicates that the heating electrode 503 in the flexible actuator 5 cannot work normally, and it is necessary to remove the heating power of the heating electrode and check whether the device is normal;

[0069] If the measured temperature of the temperature sensing electrode 4 reaches a preset temperature threshold and the measured bending angle of the strain sensing electrode 3 reaches a preset bending angle threshold, it indicates that the device is successfully grasped;

[0070] If the measured temperature of the temperature sensing electrode 4 reaches the preset temperature threshold, but the measured bending angle of the strain sensing electrode 3 is lower than the preset bending angle threshold, the grasping action is intelligently adjusted by further increasing the heating power of the heating electrode 503 in the flexible actuator 5:

[0071] If, after the heating electrode power is increased, the measured temperature of the temperature sensing electrode 4 is greater than the preset temperature threshold, and the measured bending angle of the strain sensing electrode 3 continues to increase until it reaches the preset bending angle threshold, it indicates that the device has successfully achieved grasping after intelligently adjusting the grasping action;

[0072] If after the power of the heating electrode is increased, the measured temperature of the temperature sensor 4 is greater than the preset temperature threshold, and the measured bending angle of the strain sensing electrode 3 is always lower than the preset bending angle threshold, it means that the size of the grasped object is too large and not suitable for grasping. In this case, it is necessary to remove the heating power of the heating electrode 503 in the flexible actuator 5 through feedback control to avoid burning the device, release the grasping action, and realize the intelligent release function of the device.

[0073] The above-mentioned intelligent flexible gripper with multimodal sensing capability detects the distance of the grasped object through a proximity sensor, and triggers the grasping action when it approaches the flexible base 1, which can greatly improve the grasping efficiency; through the real-time temperature and bending angle sensed by the temperature sensing electrode 4 and the strain sensing electrode 3, the flexible actuator 5 heating electrode power is adaptively controlled to adjust the deformation degree of the flexible gripper, realizing the closed-loop control and intelligent grasping and releasing functions of the device, and significantly improving the integration and intelligence of the device. Example 2:

[0074] The following Figures 1 to 3 and Figure 5 The illustrated embodiment is taken as an example to illustrate the structure of the intelligent flexible gripper with multimodal sensing capability and the intelligent grasping method thereof of the present invention.

[0075] A 40 nm thick Ag film with a loosely arranged cluster structure was deposited on a 100 μm thick polyethylene (PE) film 501 using magnetron sputtering. A patterned gold electrode was then formed using a mask. The film was pre-stretched to a certain strain to induce a through-crack, creating a strain sensing electrode 3. A certain amount of reduced graphene oxide (RGO) powder was dissolved in isopropyl alcohol and ultrasonically dispersed to produce an RGO solution. The area immediately adjacent to the strain sensing electrode was plasma-modified, then uniformly coated with an RGO film. After curing at room temperature for 12 hours, a patterned RGO temperature sensing electrode 4 was fabricated using laser etching. On the other side of the strain and temperature sensing electrode, a heating silver electrode 503 is prepared by screen printing. After curing at room temperature for 12 hours, a conductive silver paste is used to bond a wire 6 from the pin position of the silver film, RGO film and the heating silver electrode and lead it out. Then, the film prepared with the strain sensing electrode 3, the temperature sensing electrode 4 and the heating silver electrode 503 is placed in a heating furnace and kept at 50°C for 2 hours. After cooling, it is taken out and a polyimide (PI) flexible layer 502 with a low thermal expansion coefficient and a thickness of 20 μm is covered on the surface of the heating silver electrode 503 to prepare a flexible actuator 5 with integrated temperature sensing electrode and strain sensing electrode. Figure 2 As shown. The four flexible actuators 5 integrated with the strain sensing electrodes 3 and the temperature sensing electrodes 4 are assembled together with the flexible base 1 and the flexible clamp 2, as shown. Figure 1 As shown, the wires 6 from each electrode are connected to the signal acquisition and processing system to achieve 4-way voltage output for driving and 8-way independent resistance signal acquisition for temperature sensing and strain sensing. The proximity sensor based on optical principle is assembled in the flexible base 1, as shown in FIG. Figure 3As shown, the transmitting assembly includes an LED light source 701 and a light source circuit board 702 mounted on one side of the flexible base 1. The receiving assembly, located on the other side, includes a photodetector 703 and a corresponding circuit board 704. The LED light source 701 is arranged toward the receiving assembly for transmitting a light beam, and the photodetector 703 is arranged toward the transmitting assembly for receiving a light beam. The transmitting assembly is led out via a wire 6 for driving the light source, and the receiving assembly is led out via a wire 6 for signal acquisition.

[0076] When the device is working, the light emitted by the LED light source 701 in the optical proximity sensor propagates in the cavity of the flexible base 1 and is received by the photodetector 703 to detect the photoelectric signal. When the grasped object appears on the light plane, the light is blocked by the grasped object, causing the photoelectric signal detected by the photodetector to decrease. At this time, it is judged that the distance between the grasped object and the flexible base 1 has reached the threshold, and the heating silver electrode 503 in the flexible actuator 5 is automatically triggered to work, causing the flexible actuator 5 to heat up. Due to the different thermal expansion coefficients of the two layers of PE and PI flexible films, the flexible actuator 5 moves toward the flexible base 1. A bending deformation occurs in the center direction of the opening and drives the flexible clamp 2 to bend and perform a grasping action. At the same time, the signal acquisition and processing system collects the resistance signals of the temperature sensing electrode 4 and the strain sensing electrode 3 and calculates the real-time temperature and bending angle of the device, and judges the relationship between the real-time temperature and bending angle and the temperature threshold and bending angle threshold preset in the signal acquisition and processing system. The heating power of the heating electrode 503 in the flexible actuator 5 is adaptively controlled to adjust the deformation degree of the flexible clamp 2, thereby realizing the closed-loop control and intelligent grasping and releasing functions of the device. The specific adaptive control steps are carried out with reference to Example 1. Example 3:

[0077] The following Figures 1 to 3 and Figure 5 The illustrated embodiment is taken as an example to illustrate the structure of the intelligent flexible gripper with multimodal sensing capability and the intelligent grasping method thereof of the present invention.

[0078] The surface of a 100 μm thick polyethylene (PE) film 501 was plasma modified, and a silver nanowire (AgNWs) ethanol dispersion and a conductive polymer PEDOT:PSS were uniformly coated at adjacent positions. After curing at room temperature for 12 hours, patterned AgNWs strain sensing electrodes 3 and PEDOT:PSS temperature sensing electrodes 4 were prepared by laser etching. On the other side of the strain and temperature sensing electrode, a heated silver electrode 503 was prepared by screen printing. After curing at room temperature for 12 hours, a conductive silver paste was used to bond a wire 6 from the pin positions of AgNWs, PEDOT:PSS and the heated silver electrode and lead out. Subsequently, the film prepared with the strain sensing electrode 3, the temperature sensing electrode 4 and the heated silver electrode 503 was placed in a heating furnace and kept at 50°C for 2 hours. After cooling, it was taken out and a flexible polyimide (PI) layer 502 with a low thermal expansion coefficient and a thickness of 30 μm was covered on the surface of the heated silver electrode 503 to prepare a flexible actuator 5 with integrated temperature sensing electrode and strain sensing electrode. Figure 2 shown.

[0079] The four flexible actuators 5 integrated with the strain sensing electrodes 3 and the temperature sensing electrodes 4 are assembled together with the flexible base 1 and the flexible gripper 2, as shown in FIG. Figure 1 As shown, the wires 6 from each electrode are connected to the signal acquisition and processing system to achieve 4-way voltage output for driving and 8-way independent resistance signal acquisition for temperature sensing and strain sensing. The proximity sensor based on optical principle is assembled in the flexible base 1, as shown in FIG. Figure 3 As shown, the transmitting assembly includes an LED light source 701 and a light source circuit board 702 mounted on one side of the flexible base 1. The receiving assembly, located on the other side, includes a photodetector 703 and a corresponding circuit board 704. The LED light source 701 is arranged toward the receiving assembly for transmitting a light beam, and the photodetector 703 is arranged toward the transmitting assembly for receiving a light beam. The transmitting assembly is led out via a wire 6 for driving the light source, and the receiving assembly is led out via a wire 6 for signal acquisition.

[0080] During operation, light emitted by the LED light source 701 in the optical proximity sensor propagates within the cavity of the flexible base 1 and is received by the photodetector 703, which detects a photoelectric signal. When an object to be grasped appears in the light plane, the light is blocked by the object, causing the photoelectric signal detected by the photodetector to decrease. At this point, it is determined that the distance between the object and the flexible base 1 has reached a threshold, automatically triggering the heating silver electrode 503 in the flexible actuator 5 to operate, causing the flexible actuator 5 to heat up. Due to the different thermal expansion coefficients of the PE and PI flexible films, the flexible actuator 5 bends toward the center of the opening of the flexible base 1, driving the flexible gripper 2 to bend and grasp. Simultaneously, the signal acquisition and processing system collects the resistance signals of the temperature sensing electrode 4 and the strain sensing electrode 3, calculates the real-time temperature and bending angle of the device, and determines the relationship between the real-time temperature and bending angle and the temperature and bending angle thresholds preset in the signal acquisition and processing system. The power of the flexible actuator heating electrode 503 is adaptively controlled to adjust the deformation of the flexible gripper 2, thereby achieving closed-loop control and intelligent grasping and releasing functions of the device. The specific adaptive control steps are carried out in accordance with Example 1. Example 4:

[0081] The following Figures 1 to 3 and Figure 5 The illustrated embodiment is taken as an example to illustrate the structure of the intelligent flexible gripper with multimodal sensing capability and the intelligent grasping method thereof of the present invention.

[0082] Polydimethylsiloxane (PDMS) and a curing agent were mixed in a 10:1 ratio and stirred to obtain a PDMS emulsion. The emulsion was then allowed to stand in a vacuum dryer for 30 minutes to defoam. The emulsion was then poured onto a silicon wafer, centrifuged using a spinner, and dried in an oven at 80°C. The PDMS film was then peeled off to obtain a thin PDMS film. A 30 nm thick Au film was deposited on the 200 μm thick PDMS film using electron beam evaporation, and patterned gold electrodes were formed using a mask. The film was pre-stretched to a certain strain to induce a through-crack, resulting in a strain sensing electrode 3. The area immediately adjacent to the strain sensing electrode was plasma-modified and then uniformly coated with the conductive polymer PEDOT:PSS. After curing at room temperature for 12 hours, the patterned PEDOT:PSS temperature sensing electrode 4 was fabricated using laser etching. On the other side of the strain and temperature sensing electrodes, a heated silver electrode 503 was prepared by screen printing. After curing at room temperature for 12 hours, a conductive silver paste was used to bond a wire 6 from the pin positions of the gold film, PEDOT:PSS and the heated silver electrode and lead out. Subsequently, the film prepared with the strain sensing electrode 3, the temperature sensing electrode 4 and the heated silver electrode 503 was placed in a heating furnace and kept at 50°C for 2 hours. After cooling, it was taken out and a flexible polyimide (PI) layer 502 with a low thermal expansion coefficient and a thickness of 50 μm was covered on the surface of the heated silver electrode 503 to prepare a flexible actuator 5 with integrated temperature sensing electrode and strain sensing electrode. Figure 2 shown.

[0083] The four flexible actuators 5 integrated with the strain sensing electrodes 3 and the temperature sensing electrodes 4 are assembled together with the flexible base 1 and the flexible gripper 2, as shown in FIG. Figure 1 As shown, the wires 6 leading out of each electrode are connected to the signal acquisition and processing system to achieve 4-way voltage output for driving and 8-way independent resistance signal acquisition (for temperature sensing and strain sensing). The proximity sensor based on optical principle is assembled in the flexible base 1, as shown in FIG. Figure 3 As shown, the transmitting assembly includes an LED light source 701 and a light source circuit board 702 mounted on one side of the flexible base 1. The receiving assembly, located on the other side, includes a photodetector 703 and a corresponding circuit board 704. The LED light source 701 is arranged toward the receiving assembly for transmitting a light beam, and the photodetector 703 is arranged toward the transmitting assembly for receiving a light beam. The transmitting assembly is led out via a wire 6 for driving the light source, and the receiving assembly is led out via a wire 6 for signal acquisition.

[0084] During operation, light emitted by the LED light source 701 in the optical proximity sensor propagates within the cavity of the flexible base 1 and is received by the photodetector 703, which detects a photoelectric signal. When an object to be grasped appears in the light plane, the light is blocked by the object, causing the photoelectric signal detected by the photodetector to decrease. At this point, it is determined that the distance between the object and the flexible base 1 has reached a threshold, automatically triggering the heating silver electrode 503 in the flexible actuator 5 to operate, causing the flexible actuator 5 to heat up. Due to the different thermal expansion coefficients of the PE and PI flexible films, the flexible actuator 5 bends toward the center of the opening of the flexible base 1, driving the flexible gripper 2 to bend and grasp. Simultaneously, the signal acquisition and processing system collects the resistance signals of the temperature sensing electrode 4 and the strain sensing electrode 3, calculates the real-time temperature and bending angle of the device, and determines the relationship between the real-time temperature and bending angle and the temperature and bending angle thresholds preset in the signal acquisition and processing system. The power of the flexible actuator heating electrode 503 is adaptively controlled to adjust the deformation of the flexible gripper 2, thereby achieving closed-loop control and intelligent grasping and releasing functions of the device. The specific adaptive control steps are carried out in accordance with Example 1. Example 5:

[0085] The following Figures 1 to 2 and Figure 6 The illustrated embodiment is taken as an example to illustrate the structure of the intelligent flexible gripper with multimodal sensing capability and the intelligent grasping method thereof of the present invention.

[0086] In this embodiment, the structure and preparation method of the flexible actuator 5, which consists of the strain sensor 3, the temperature sensor 4, and the heated silver electrode 503, are similar to those in Example 1. The difference is that a capacitive proximity sensor 705 is used to monitor the distance between the grasped object and the flexible base 1, and the heating electrode 503 in the flexible actuator is automatically triggered when a certain threshold is reached.

[0087] A 30 nm thick Au metal film is deposited on the surface of a 100 μm thick polyethylene (PE) film 501 using electron beam evaporation. A patterned gold electrode is obtained with the help of a mask. A conductive silver paste is used to bond a wire 6 to the pin position and lead it out to prepare a capacitive proximity sensor 705, which is then placed on the bottom surface of the flexible base 1. Figure 6 As shown. The four flexible actuators 5 integrated with the strain sensing electrodes 3 and the temperature sensing electrodes 4 and the capacitive proximity sensor 705 are assembled together with the flexible base 1 and the flexible gripper 2, as shown. Figure 1 As shown, the wires 6 leading out of each electrode are connected to the signal acquisition and processing system to achieve 4-way voltage output for driving, 8-way independent resistance signal acquisition for temperature sensing and strain sensing, and 1-way capacitance signal acquisition for proximity judgment.

[0088] During operation, the proximity sensor's electric field distribution changes with the approach of the grasped object, reflected in a change in capacitance. When the rate of change in capacitance reaches a certain threshold, the grasped object is deemed sufficiently close to the flexible base 1, automatically triggering the activation of the heating silver electrode 503 in the flexible actuator 5, causing the flexible actuator 5 to heat up. Due to the different thermal expansion coefficients of the two flexible films in the flexible actuator 5, the flexible actuator 5 bends toward the center of the opening of the flexible base 1, driving the flexible gripper 2 to bend and grasp. Simultaneously, the signal acquisition and processing system collects the resistance signals from the temperature sensing electrode 4 and the strain sensing electrode 3, calculates the device's real-time temperature and bending angle, and determines their relationship to preset temperature and bending angle thresholds in the signal acquisition and processing system. After the capacitive proximity sensor 705 triggers the flexible actuator 5, it adaptively controls the heating power of the heating electrode 503 in the flexible actuator 5 according to the operating principles of Example 1 to adjust the deformation of the flexible gripper 2, achieving closed-loop control and intelligent grasping and releasing capabilities.

[0089] The above specific embodiments are used to illustrate the present invention rather than to limit the present invention. Any modifications and changes made to the present invention within the spirit of the present invention and the protection scope of the claims shall fall within the protection scope of the present invention.

[0090] The above description is only a preferred embodiment of the present invention. Therefore, any equivalent changes or modifications made according to the structure, characteristics and principles described in the scope of the patent application of the present invention are included in the scope of the patent application of the present invention.

Claims

1. An intelligent flexible gripper with multimodal sensing capability, characterized by: The invention comprises a flexible base (1), a flexible clamping claw (2), a flexible actuator (5) and a proximity sensor (7); a cavity is provided inside the flexible base (1), the top surface of the cavity is opened for facing the grasping object, a plurality of flexible clamping claws (2) are arranged around the opening of the top surface of the flexible base (1), the bottom of the flexible clamping claw (2) is swingably and rotatably connected to the edge of the top surface opening of the flexible base (1) through the flexible actuator (5), and a proximity sensor (7) is provided at the bottom of the flexible base (1) for detecting whether the grasping object enters the cavity of the flexible base (1); The flexible actuator (5) is embedded with a strain sensing electrode (3) and a temperature sensing electrode (4), and the strain sensing electrode (3) and the temperature sensing electrode (4) are used to detect the temperature and bending angle of the flexible actuator (5) when it is bent and deformed; The flexible actuator (5) is mainly composed of two layers of flexible films (501, 502) and a heating electrode (503) located between the two layers of flexible films (501, 502). The thermal expansion coefficients of the materials of the two layers of flexible films (501, 502) are different. The thermal expansion coefficient of the layer of flexible film (501 / 502) close to the center of the top opening of the flexible base (1) is lower than that of the layer of flexible film (501 / 502) far from the center of the top opening of the flexible base (1).

2. The intelligent flexible gripper with multimodal sensing capability according to claim 1, characterized in that: One end of the flexible actuator (5) is connected to the flexible clamping claw (2), and the other end of the flexible actuator (5) is connected to the edge of the top opening of the flexible base (1).

3. The intelligent flexible gripper with multimodal sensing capability according to claim 1, characterized in that: The top opening of the flexible base (1) is arranged in a square shape, and a flexible clamping claw (2) is connected to each of the four sides of the square. The four flexible clamping claws (2) are all in the shape of an isosceles triangle, and when the four flexible clamping claws (2) are closed toward the opening and cover the opening, a pyramid shape is formed.

4. The intelligent flexible gripper with multimodal sensing capability according to claim 1, characterized in that: The proximity sensor (7) comprises a transmitting component located on one side and a receiving component located symmetrically on the other side; the transmitting component comprises an LED light source (701) and a light source circuit board (702), the light source circuit board (702) is provided with an LED light source (701), and the LED light source (701) is arranged toward the receiving component for transmitting a light beam; the receiving component comprises a photodetector (703) and a detector circuit board (704), the detector circuit board (704) is provided with a photodetector (703), and the photodetector (703) is arranged toward the transmitting component for receiving the light beam.

5. The intelligent flexible gripper with multimodal sensing capability according to claim 1, characterized in that: The proximity sensor (7) is configured as a capacitive proximity sensor (705), and the capacitive proximity sensor (705) is electrically connected to an external signal acquisition and processing system via a wire (6).

6. An intelligent grasping method applied to the intelligent flexible gripper according to any one of claims 1 to 5, characterized in that: When the intelligent flexible gripper is working, a proximity sensor (7) is used to detect in real time whether the target object of the gripping object enters the cavity of the flexible base (1). When it is detected in real time that the gripping object enters the cavity of the flexible base (1), the heating electrode (503) in the flexible actuator (5) is controlled to operate, so that the temperature of the flexible film (501 / 502) is increased. The thermal expansion coefficients of the two layers of flexible film are different, so that the flexible actuator (5) generates a bending deformation toward the center of the opening of the flexible base (1) and drives the flexible gripper (2) to bend and perform a gripping action; By collecting the electrical signals of the strain sensing electrode (3) and the temperature sensing electrode (4) and calculating the real-time temperature and bending angle of the intelligent flexible gripper, the power of the heating electrode (503) in the flexible actuator (5) is adaptively controlled according to the real-time temperature and bending angle to adjust the grasping action and deformation degree of the flexible gripper (2), thereby realizing closed-loop control and intelligent grasping and releasing functions of the intelligent flexible gripper.

7. The intelligent grasping method according to claim 6, characterized in that: The proximity sensor (7) detects whether the distance between the target object of the grasping object and the bottom surface of the flexible base (1) of the intelligent flexible gripper reaches a preset distance threshold, thereby determining whether the target object of the grasping object enters the cavity of the flexible base (1).

8. The intelligent grasping method according to claim 6, characterized in that: The flexible actuator (5) and the flexible clamping claw (2) have a pre-fixed matching relationship curve between the temperature and the bending angle during deformation. When the temperature and the bending angle detected in real time do not match on the relationship curve, the adaptive feedback control increases or decreases the heating power of the heating electrode (503) in the flexible actuator (5), drives the flexible clamping claw (2) away from the opening of the flexible base (1), and adjusts the grasping state; if the temperature and the bending angle still cannot be matched on the relationship curve, it is determined that the grasping object is not suitable for grasping, and the heating is stopped and the target object is released; When the temperature and bending angle detected in real time match on the relationship curve, the adaptive feedback control maintains the heating power of the heating electrode (503) in the flexible actuator (5), driving the flexible gripper (2) to maintain a gripping state of the gripping object.

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