A self-aware soft robot

Abstract

The present invention discloses a self-sensing soft robot, including a deformable soft structure, a digital resistance meter, a controller, a driver and a motor; the soft structure includes an upper structure and a lower structure; wherein the upper structure and the lower structure are connected together through an intermediate transition structure, a hydrogel sensor is embedded in the upper structure and the lower structure, and a fishing line for controlling the telescopic bending of the soft structure is penetrated in the upper structure and the lower structure; the hydrogel sensor is connected to the digital resistance meter, the digital resistance meter is used for an A / D module, and the A / D module is used to convert the resistance value of the hydrogel sensor into a digital quantity that can be transmitted to the controller through an RS485 protocol, the controller is connected to the driver, and the driver is connected to the motor. Compared with a rigid robot, the soft robot designed by the present invention is more flexible and versatile, has increased autonomous perception capabilities, and can respond sensitively to external stimuli, providing an important guarantee for the realization of closed-loop control.

Description

Technical Field

[0001] The present invention relates to the field of robotics technology, and in particular to a soft robot with self-perception. Background Art

[0002] Intelligent robots are playing an increasingly wide role in our lives, but traditional rigid robots can only move horizontally or rotate when interacting with the natural environment, and have limited adaptability to the environment, making them difficult to use in complex unstructured environments. For this reason, soft robots based on flexible materials have emerged, also known as soft robots. Soft robots are soft and can change shape, have infinite degrees of freedom, and can complete related tasks in narrow crevices of ruins and in organisms. However, due to the limitations of rigid sensors such as compatibility with soft robots, their own size, and mechanical properties, the development of soft robots has been hindered to a certain extent.

[0003] With the rapid development of materials science, flexible sensors with good flexibility and ductility, free bending or folding, and flexible and diverse structural forms have attracted wide attention in the fields of health detection, human-computer interaction, etc. Guo Shihui et al. designed a flexible sensor based on the saliency of human motion, which constructs a three-dimensional human model and sets human body parameters in the three-dimensional human model; through different operations, deformation analysis is performed to determine the wiring starting point and wiring direction of the flexible sensor, so as to optimize the layout of the position of the flexible sensor, improve the flexible sensor's ability to capture human deformation information, and can be widely used in flexible stretching sensors such as fabric sensors. In practical applications, MXene (maike ene) flexible stress / strain sensors can be used to monitor large deformation movements of the human body, such as joint movement, muscle contraction, and small deformation of life signals. In addition, MXene flexible stress / strain sensors can also be connected to wireless transmitters for remote monitoring, providing a possibility for long-distance human-computer dialogue. At present, there are flexible sensors that imitate plants, using leaves or petals of some plants in nature as templates for base materials, combined with some modern process technologies, such as graphene deposition and metal sputtering, to prepare flexible electrodes. At present, non-contact flexible sensors mainly use the electronic properties on the surface of the atomic structure of certain nanomaterials, or use high-resolution optical sensors, which can not only achieve high spatial resolution and sensitivity, but also achieve full-field sensing within a certain range, thereby effectively improving the comprehensiveness and continuity of the monitoring and surveillance structure. Flexible sensors usually also use reduced graphene oxide, carbon nanotubes, etc. as materials. Tong Kai et al. made a flexible graphene pressure sensor, which includes a flexible substrate, a microstructure bottom layer, an electrode, a graphene film and a flexible encapsulation layer; the preparation method includes preparing a graphene film, making a flexible substrate and performing a reverse molding operation on the flexible substrate, making a cylindrical array, and finally combining to prepare a flexible graphene pressure sensor. The carbon nanotube conductive ink designed by Duan Qiuyan et al. is prepared by modifying carbon nanotubes with a mixed solution of cellulose and dopamine. The carbon nanotube conductive ink can be used to prepare flexible fabric-based strain sensors. The above flexible sensors have high performance, high stability, high sensitivity, excellent rapid response characteristics and durability, low cost, and realize green manufacturing.

[0004] Although flexible sensors can currently meet the needs of specific objects, the destruction of the contact state of the conductive material during deformation usually leads to instability of the strain sensor. In addition, the curvature of most flexible materials is limited, which limits their development in the field of high-precision measurement. The materials of flexible substrates are limited, and in many cases, graphene materials are required to manufacture flexible sensors, which has not been mass-produced for a long time. At the same time, the soft robots made of these materials have low sensitivity in receiving responses, cannot react quickly, and are unstable, so the application range of robots is relatively narrow.

[0005] Sensors made of hydrogel materials have superior performance. PAM (polyacrylamide) hydrogel has good performance in the fields of water purification. The PAM hydrogel prepared by Weiwei Fan et al. has good in vitro cell compatibility, is a shape memory hydrogel, has acceptable mechanical and drug release properties, and can be used in wound dressings. Yuyan Yang et al. prepared a graphene oxide (GO) / polyacrylamide (PAM) composite hydrogels. The main driving force for the formation of the composite hydrogel is hydrogen bonding, electrostatic interaction, etc. When the amount of GO (PAM) is increased at a fixed PAM (GO) concentration, or when the total concentration is increased at a fixed GO molar ratio and the ratio of PAM is 1:1, the viscoelasticity of GO / PAM is significantly improved. The composite hydrogel is more efficient in adsorbing toxic dyes and is an environmentally friendly water purifier. Through research, it was found that the PAM composite hydrogel with the addition of conductive active material PEDOT:PSS has good compatibility, mechanical properties, toughness and plasticity. At the same time, the electrochemical properties of the hydrogel are also extremely superior, with rapid response and excellent electrical stability. The flexible strain sensor prepared using this hydrogel has the characteristics of flexibility, stretchability, compressibility, etc., has good repeatability and working stability, and shows great development potential in the application of soft robots.

[0006] Therefore, the composite hydrogel can be used to design the robot structure and fully embedded to make it a whole, thereby realizing the self-perception function of the soft robot (using the principles of physical artificial intelligence to realize the behavior and cognition of the soft robot), which is of great significance to the development of the field of soft robot perception.

[0007] There are two main categories of soft robot perception: external and internal perception. Cameras can be used for external perception of soft robots. Visual sensors are used to obtain environmental information and implement feedback motion control on the robot. For a six-degree-of-freedom hand-eye robot system, Wang Dahao et al. proposed a new image-based visual servoing method, which imposes prescribed transient and steady-state responses on the image feature coordinate error, satisfying the visibility constraints caused by the camera field of view (FOV) limitation. For the robot return path determination, Wang Xingtao et al. proposed a method for determining the return path of an inspection robot based on visual servoing. This method uses a visual servoing control method to control the speed of the inspection robot and then performs parameter tuning on the mechanical parameters of the inspection robot after speed data processing. Finally, based on the tuned parameters, the robot return path is planned and processed. Some scholars have provided a vision-based external state perception method for a spatial cell robot. This method establishes an image database of different types of cells in a spatial cell robot and performs image annotation. The labeled images are trained on a network based on deep learning, and the relative distance and angle relationship between the active connection surface and the passive connection surface are derived by combining the intrinsic parameters of the camera. This method can not only measure the relative distance and relative rotation angle to the target object, but also identify different types of target objects and obstacles according to the needs of the space cell robot. The angle measurement range is also larger, which is suitable for the external state perception of the space cell robot under any translation or rotation movement. However, these perception methods are usually difficult to use in unstructured spaces, so it is necessary to study the internal perception of the robot.

[0008] Internal perception of soft robots can use tools such as flex sensors, inclinometers, fiber optic sensors, and magnetic sensors. Li Hong et al. proposed a soft fiber curvature sensor for finger joint angle proprioception, which consists of a protective silicone layer, a fiber curvature sensor, and two wearable fingertips. The optical path difference between the sensor's core mode and the surrounding core mode changes with the curvature, causing the interference spectrum to shift. Through the verification test of the sensing device, this sensing method is effective for measuring the bending shape of the joint angle model. Currently, almost every joint of consumer, professional service, or social robot uses 2 or more magnetic angle position sensors. At least 1 magnetic angle position sensor is required for each axis of motion or joint rotation. Many robots today use small and powerful brushless DC motors (BLDC) to move the robot's joints and limbs. In order to drive the motor correctly, it is necessary to know the current position of the motor. Magnetic angle position sensor ICs are increasingly used to provide motor commutation feedback for motor controllers that move joints. In addition, closed-loop motor control of robot joints also requires angle position feedback of joint gears. Such sensors are not suitable for large deformations of themselves. Dong Zhou et al. implemented a method for self-sensing control of TAM (twisted artificial muscle made of nylon) temperature by real-time monitoring of the resistance of the heating wire, and achieved precise control of the TAM temperature. Using the self-sensing control method, the simultaneous control of 18 TAMs was achieved. Based on the principle of insect bionics, a new step-by-step walking method was adopted to realize a bionic soft hexapod robot with multi-motion and load-bearing capacity. In addition, due to the good environmental adaptability of TAM, the bionic robot can achieve amphibious movement under land and underwater conditions, and the corresponding maximum load capacity is 300g and 1kg, respectively. This not only provides a reliable self-sensing control method for TAMs, but also promotes the development of bionic soft robots. Lei Qin, Yucheng Tang et al. developed a soft mobile robot with high maneuverability and self-sensing ability for obstacle detection and avoidance. They developed a self-sensing method that modeled the robot body as a deformable capacitor. By measuring the real-time capacitance of the robot body, the robot can detect obstacles when the peak capacitance suddenly drops. This sensing method uses the robot body instead of external sensors to achieve obstacle detection, which greatly reduces the weight and complexity of the robot system. The two-dimensional maneuverability and self-perception capabilities ensure successful obstacle detection and avoidance, paving the way for the development of lightweight intelligent soft mobile robots.

[0009] In recent years, with the rapid development of materials science, hydrogels have received extensive attention. Hydrogels are made of a variety of materials. Yang Zhixi and others designed a hydrogel patch and its preparation method and application. The hydrogel patch includes a first hydrogel layer and a second hydrogel layer stacked together. The water content of the first hydrogel layer is 30% to 40%, and the water content of the second hydrogel layer is 50% to 60%. The conductivity of the hydrogel patch is 150μS / cm to 250μS / cm. The hydrogel patch can not only fix the microneedles on the skin surface, but also can be used with instruments to accelerate the dissolution of the microneedles, promote the diffusion and absorption of the effective ingredients, thereby greatly shortening the use time of the microneedles, and plays an important role in medical treatment. Lv Hua and others prepared a polyamino acid hydrogel, which has excellent biocompatibility and biodegradability, can well support stem cell growth and cartilage differentiation, and has good immunoregulatory properties. Wang Jing and others prepared a galactofucan sulfate hydrogel. On the one hand, the hydrogel can inhibit bacterial growth, adsorb inflammatory factors, reduce wound inflammation, and provide a good environment for wound healing; on the other hand, it can promote the proliferation and migration of fibroblasts, promote the formation of granulation tissue, and promote wound healing. It is particularly suitable for the treatment and care of chronic difficult-to-heal wounds that are widely present in clinical practice, such as diabetic foot and bedsores. PAM hydrogel is a hydrophilic polymer with good biocompatibility and has been widely used in water treatment, petroleum, electrochemistry and other fields. However, the general PAM hydrogel has poor conductivity and lacks mechanical strength, which limits its application in the field of flexible electronics. The sensitivity factor of PAM / PEDOT:PSS hydrogel sensors is generally higher than that of pure PAM hydrogel sensors. As a sensing material, it has better rapid response ability and excellent electrical stability. The application of PEDOT:PSS hydrogel in soft robots shows amazing potential. PEDOT:PSS hydrogel has good compatibility, mechanical properties, toughness and plasticity. At the same time, the electrochemical properties of the hydrogel are also extremely superior, with rapid response ability and excellent electrical stability. The flexible strain sensor prepared using this hydrogel has the characteristics of flexibility, stretchability, compressibility, etc., and has good repeatability and working stability. However, despite the above excellent characteristics, there is little work on its use in soft robot perception.

[0010] In summary, most robots currently used in life rely on external perception systems, such as cameras to replace vision and infrared laser technology. There are few robots with the ability to correct and respond to environmental changes, that is, autonomous perception. Traditional rigid robots are not suitable for the application of self-perception systems. Traditional rigid sensors are currently unable to match the large deformation of soft robots in unstructured spaces and infinite-dimensional motion. The lack of sensation and reaction limits their huge potential. Summary of the invention

[0011] The present invention provides a soft robot with self-perception to solve the technical problems that traditional rigid robots are not suitable for applications in self-perception systems, traditional rigid sensors cannot match the large deformation of soft robots in unstructured spaces, perform infinite-dimensional motion, and lack of sensation and reaction, which limits their huge potential.

[0012] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0013] A self-sensing soft robot, comprising a deformable soft structure, a digital resistance meter, a controller, a driver and a motor;

[0014] The software structure includes an upper structure and a lower structure; wherein the upper structure and the lower structure are connected together through an intermediate transition structure, and hydrogel sensors are embedded in the upper structure and the lower structure, and fishing lines for controlling the extension and bending of the software structure are passed through the upper structure and the lower structure; the hydrogel sensor is connected to the digital display ohmmeter, and the digital display ohmmeter is used for the A / D module, and the A / D module is used to convert the resistance value of the hydrogel sensor into a digital quantity that can be transmitted to the controller through the RS485 protocol, and the controller is connected to the driver, and the driver is connected to the motor, and the driver controls the movement of the software structure by driving the motor to operate.

[0015] Furthermore, the preparation process of the hydrogel sensor includes:

[0016] The acrylamide powder was dissolved in distilled water, and dissolved under ultrasonic oscillation at 25°C for 5 minutes to form an aqueous solution, and then 0.2 g of PEDOT:PSS was added to the aqueous solution. After the solution was evenly mixed, a crosslinker, an initiator and a catalyst were added, and then ultrasonically dissolved in an ice bath for ten minutes to obtain an AM / PEDOT:PSS precursor solution; the prepared precursor solution was poured into a customized polytetrafluoroethylene plate mold, and reacted in an oven at 60°C for 1 hour to obtain a PAM / PEDOT:PSS hydrogel;

[0017] The PAM / PEDOT:PSS hydrogel was cut into a preset shape using a polytetrafluoroethylene plate mold;

[0018] The cut hydrogel is connected to a lead wire to obtain the hydrogel sensor.

[0019] Furthermore, the cross-linking agent is 2-mercaptobenzoic acid MBA, the initiator is ammonium sulfate APS, and the catalyst is tetramethylethylenediamine TEMED.

[0020] Furthermore, an upper disc is arranged at one end of the upper structure away from the lower structure, a middle disc is arranged in the intermediate transition structure, and a lower disc is arranged at one end of the lower structure away from the upper structure; wherein,

[0021] The upper structure is provided with a first accommodating cavity and a first hollow cylinder penetrating the upper structure in the longitudinal direction thereof, a first hydrogel sensor is embedded in the first accommodating cavity, a first fishing line for controlling the extension and bending of the upper structure is passed through the first hollow cylinder, a second accommodating cavity and a second hollow cylinder penetrating the lower structure in the longitudinal direction thereof is provided inside the lower structure, a second hydrogel sensor is embedded in the second accommodating cavity, and a second fishing line for controlling the extension and bending of the lower structure is provided inside the second hollow cylinder;

[0022] The lead wire of the first hydrogel sensor passes through the upper disk and is led out from the upper disk; one end of the first fishing line is led out from the upper disk, and the other end passes through the middle disk and is tied, and then sealed with glue; one end of the second fishing line passes through the middle disk and the upper structure, and passes through the upper disk, and is led out from the upper disk; the other end passes through the lower disk and is tied, and then sealed with glue; the lead wire of the second hydrogel sensor is led out from the middle disk.

[0023] Furthermore, the number of the first accommodating cavities and the second accommodating cavities are both three, a first hydrogel sensor is embedded in each first accommodating cavity, and a second hydrogel sensor is embedded in each second accommodating cavity; the number of the first hollow cylinders and the second hollow cylinders are both three, a first fishing line is passed through each first hollow cylinder, and a second fishing line is passed through each second hollow cylinder.

[0024] Furthermore, the length of the first accommodating cavity is 2 mm longer than the length of the first hydrogel sensor, so that after the first hydrogel sensor is installed, the first accommodating cavity is sealed by a cover to seal the first hydrogel sensor, and each cover is provided with a hole for the sensor lead to pass through;

[0025] The length of the second accommodating cavity is 2 mm longer than the length of the second hydrogel sensor, so that after the second hydrogel sensor is installed, the second accommodating cavity is sealed by a cover to seal the second hydrogel sensor, and each cover is provided with a hole for the sensor lead to pass through.

[0026] Furthermore, the data calibration process of the hydrogel sensor includes:

[0027] After the hydrogel sensor is integrated into the soft robot, a digital resistance meter is used to measure the resistance change of the hydrogel sensor, and the resistance change data is recorded and the fitting data is analyzed through a python program. At the same time, the state of the soft robot is captured in real time, and the angle change of the soft robot is measured;

[0028] While the soft robot is being driven by a motor, the bending angle of the soft structure and the resistance value of the hydrogel sensor are measured synchronously to perform data analysis and obtain the corresponding relationship between the resistance value and the bending angle.

[0029] Furthermore, when the soft robot performs data communication, it uses the RS485 protocol to transmit communication data.

[0030] The beneficial effects brought about by the technical solution provided by the present invention include at least:

[0031] The advantage of the present invention is that the sensor is made of a new hydrogel flexible material, and a series of work such as signal acquisition, calibration, and signal output are performed on this basis to manufacture a soft robot with a cascade structure with self-sensing function and higher flexibility, and the self-sensing of the soft robot is realized in the form of physical artificial intelligence. It is not only more flexible and versatile than a rigid robot, and increases the robot's autonomous perception ability, but also can respond sensitively to external stimuli, providing an important guarantee for the realization of closed-loop control. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0033] Figure 1 is a schematic diagram of the design of a soft robot provided by an embodiment of the present invention;

[0034] Figure 2 is a flow chart of the preparation of a PAM / PEDOT:PSS hydrogel sensor provided by an embodiment of the present invention;

[0035] Figure 3 is a schematic diagram of the structure of a soft robot provided by an embodiment of the present invention;

[0036] Figure 4 It is a schematic diagram of measurement wiring provided by an embodiment of the present invention.

[0037] Description of reference numerals:

[0038] 1. First through hole; 2. Second through hole; 3. Third through hole; 4. Fourth through hole; 5. Fifth through hole;

[0039] 6. Sixth through hole; 7. Seventh through hole; 8. Upper disc; 9. Middle disc; 10. Lower disc. DETAILED DESCRIPTION

[0040] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0041] This embodiment provides a self-sensing soft robot, which uses a new material PAM / PEDOT:PSS hydrogel to achieve self-sensing; wherein PAM is polyacrylamide, PEDOT is a polymer of 3,4-ethylenedioxythiophene monomers, and PSS is a polymer of styrene sulfonate monomers, and the three are organically combined to form PAM / PEDOT:PSS hydrogel. This embodiment first calibrates the resistance value and bending posture according to the resistance characteristics of the hydrogel material. In this regard, it should be noted that generally, a certain error will be generated when measuring the resistance value during the posture calibration process. Therefore, this embodiment uses a four-wire method to measure the hydrogel resistance. This method can minimize the error caused by the wire resistance to the hydrogel resistance measurement. The measured resistance value of the hydrogel is displayed by a TRM digital resistance meter, which is used in the system A / D module. The A / D module is responsible for converting the analog value of the hydrogel resistance value into a digital value that can be transmitted to the main controller (Raspberry Pi) through the RS485 protocol, and connecting the various components in series. The communication part uses RS485 protocol transmission. The RS-485 interface has good anti-noise interference, long transmission distance and high data transmission rate, and works well when used in a variety of interfaces.

[0042] In addition, most soft robots on the market have a single-segment structure, a relatively narrow range of use, and low flexibility. In this regard, the present embodiment makes a double-segment soft robot, which has higher sensitivity under the same driving action. The sensor used to realize the self-sensing function of the soft robot is made of a new hybrid hydrogel material, which has better rapid response ability and excellent electrical stability than ordinary sensors.

[0043] Specifically, see Figures 1 to 4 , the self-sensing soft robot of this embodiment includes a deformable soft structure, a digital resistance meter, a controller, a driver and a motor;

[0044] The software structure includes an upper structure and a lower structure; wherein the upper structure and the lower structure are connected together through an intermediate transition structure, and hydrogel sensors are embedded in the upper structure and the lower structure, and fishing lines for controlling the extension and bending of the software structure are passed through the upper structure and the lower structure; the hydrogel sensor is connected to the digital display ohmmeter, and the digital display ohmmeter is used for the A / D module, and the A / D module is used to convert the resistance value of the hydrogel sensor into a digital quantity that can be transmitted to the controller through the RS485 protocol, and the controller is connected to the driver, and the driver is connected to the motor, and the driver controls the movement of the software structure by driving the motor to operate.

[0045] Next, the structure and design process of the soft robot of this embodiment are described in detail.

[0046] ① Preparation of PAM / PEDOT:PSS hydrogel sensor, the process is as follows Figure 2 As shown, including:

[0047] The acrylamide powder was dissolved in distilled water, and dissolved under ultrasonic oscillation at 25°C for 5 minutes to form an aqueous solution, and then 0.2g of PEDOT:PSS was added to the aqueous solution. After the solution was evenly mixed, a crosslinker MBA (2-mercaptobenzoic acid), an initiator APS (ammonium sulfate) and a catalyst TEMED (tetramethylethylenediamine) were added, and then ultrasonically dissolved in an ice bath for ten minutes to obtain an AM / PEDOT:PSS precursor solution; the prepared precursor solution was poured into a customized polytetrafluoroethylene plate mold, and reacted in an oven at 60°C for 1 hour to obtain a PAM / PEDOT:PSS hydrogel;

[0048] Use a polytetrafluoroethylene plate mold to cut the PAM / PEDOT:PSS hydrogel into the desired shape;

[0049] Specifically, in this embodiment, the hydrogel sensor is cut into a cylindrical shape with a length of 50 mm and a diameter of φ5 mm. The cut hydrogel is packaged and used as a sensor to realize embedded perception in a soft robot.

[0050] ②Design of soft robots

[0051] The soft robot of this embodiment is mainly divided into two parts: upper and lower parts. Figure 3 The upper section structure is provided with an upper disc at one end away from the lower section structure, the intermediate transition structure is provided with a middle disc, and the lower section structure is provided with a lower disc at one end away from the upper section structure; wherein,

[0052] 1. The structure of the first half

[0053] The overall length of the upper half robot is 100 mm, the cross-sectional dimension of the upper disk 8 is φ20 mm, the thickness h=2 mm, and there are 7 through holes in the upper disk 8 . The first through hole 1, the second through hole 2, and the third through hole 3 have an aperture of φ5mm and are used to install the hydrogel sensor. The cross-sectional size of the accommodating cavity for placing the hydrogel sensor in the upper half is φ5mm and the length is 52mm, which is 2mm longer than the length of the hydrogel sensor. This is to enable the sensor to be sealed with a cover made of soft glue 20A, 2mm thick, and with the same cross-section as the corresponding accommodating cavity. Each cover has two small holes, and the two holes can lead out two wires of the hydrogel sensor; wherein the number of accommodating cavities is three, and a hydrogel sensor is embedded in each accommodating cavity; the hollow cylinder for placing the fishing line is 100mm long and runs through the entire upper half structure; the aperture of the fourth through hole 4, the fifth through hole 5, and the sixth through hole 6 is φ1mm, and each hole can lead out a fishing line for controlling the extension and bending of the upper half structure; the aperture of the seventh through hole 7 is φ4mm, and the hollow cylinder corresponding to the seventh through hole 7 is 100mm long and also runs through the entire upper half structure, and can be used to lead out three fishing lines for controlling the lower half structure.

[0054] 2. Intermediate transition structure

[0055] The cross-sectional dimensions of the middle disk 9 are φ18 mm, the thickness h=2 mm, and there are 13 holes in total. Except for the middle hole which is φ4 mm, the remaining holes are each φ1 mm.

[0056] 3. Structure of the lower part

[0057] The structure of the lower section is similar to that of the upper section, with only some differences in size.

[0058] The lower half of the structure is 100mm long. The three cavities for accommodating hydrogel sensors have a cross-section of φ5mm and a length of 52mm, which is 2mm longer than the length of the hydrogel sensor. This is to enable the sensor to be sealed with a cover made of soft glue 20A with a thickness of 2mm and the same cross-section as the corresponding accommodating cavity. Each cover has two small holes, which can lead out the two wires of the hydrogel sensor; the hollow cylinder for placing the fishing line has a cross-section of φ1mm and a length of 100mm, running through the entire lower half of the structure.

[0059] The three fishing lines that control the movement of the upper half structure pass downward through the three small holes of the middle disk 9 and are tied, and then the three small holes are sealed with glue to better control the telescopic bending movement of the upper half structure; the three fishing lines that control the telescopic bending of the lower half structure pass upward through the other three small holes of the middle disk 9 and are led out through the seventh through hole 7 of the upper half structure. Two wires need to be led out of each hydrogel sensor, and two wires of a hydrogel sensor are led out of each of the remaining six small holes. The cross section of the lower disk 10 is 6.53*2mm, the thickness h=2mm, and there are 3 φ1mm small holes in total. The three fishing lines that control the lower half structure can pass downward through these three small holes and be tied, and then the three small holes are sealed with glue.

[0060] Through the embedded structural design of the hydrogel sensor in the soft robot, when the fishing line that controls the movement of the robot is stretched and pulled, the hydrogel sensor will also achieve a certain degree of bending or expansion. For example, when the fishing line led out of the fourth through hole 4 is stretched, the soft robot will bend to the upper right, and then the relationship between the measured hydrogel bending angle and the resistance value will be transmitted to the computer to judge the movement of the soft robot with a certain resistance value, thereby realizing the self-sensing function of the soft robot.

[0061] ③ Wiring and measurement process, such as Figure 4 Shown

[0062] 1. Wiring:

[0063] Motor: The driver's VCC is connected to the 24V power supply, GND is connected to the power ground, PUL- and DIR- are connected to the Raspberry Pi GND, PUL+ is connected to the Raspberry Pi P23, and DIR+ is connected to P24

[0064] The RS485 expansion board is connected to the Raspberry Pi via a pin header;

[0065] Measure resistance: Insert the four wires at the measuring end into the hydrogel, connect VCC and GND to the 5V and GND of the Raspberry Pi, and connect 485A and 485B to A and B of Channle 1 of the expansion board. Connect G of Channle 1 to GND of the Raspberry Pi.

[0066] 2. Data calibration:

[0067] After the hydrogel sensor is integrated into the soft robot, the resistance change is measured using a TRM digital resistance meter, and the data is recorded and analyzed through a python program. At the same time, the state of the soft robot is captured in real time, and the angle change of the soft robot is measured manually. While the soft robot is driven by a motor, the angle of the soft structure and the resistance of the hydrogel sensor are measured synchronously for data analysis to obtain the corresponding relationship between the resistance value and the bending angle.

[0068] 3. Signal conversion:

[0069] The hydrogel resistance is measured by a resistor, analog-to-digital conversion is achieved through RS485, and the bending degree corresponding to the resistance value is obtained after program processing, thereby realizing the perception of the bending angle.

[0070] In summary, this embodiment applies the new material PAM / PEDOT:PSS hydrogel to the dual-segment soft robot, designs the internal structure of the soft robot, makes hydrogel sensors to assemble the soft robot, and performs posture calibration on it. Through A / D conversion, RS485 transmission and controller communication, it truly realizes the ability of autonomous perception. It is not only more flexible and versatile than rigid robots, but also has increased autonomous perception capabilities and can respond sensitively to external stimuli, providing important guarantees for the realization of closed-loop control.

[0071] In addition, it should be noted that, in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. The terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or terminal device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or terminal device. In the absence of further restrictions, the elements defined by the sentence "comprise one..." do not exclude the existence of other identical elements in the process, method, article or terminal device including the elements.

[0072] Finally, it should be noted that the above is a preferred embodiment of the present invention. It should be pointed out that although the preferred embodiment of the present invention has been described, for those skilled in the art, once the basic creative concept of the present invention is known, several improvements and modifications can be made without departing from the principles of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention. Therefore, the attached claims are intended to be interpreted as including the preferred embodiment and all changes and modifications that fall within the scope of the embodiments of the present invention.

Claims

1. A self-sensing soft robot, characterized in that: The self-sensing soft robot includes a deformable soft structure, a digital resistance meter, a controller, a driver and a motor; The software structure comprises an upper structure and a lower structure; wherein the upper structure and the lower structure are connected together through an intermediate transition structure, a hydrogel sensor is embedded in the upper structure and the lower structure, and a fishing line for controlling the extension and bending of the software structure is passed through the upper structure and the lower structure; the hydrogel sensor is connected to the digital resistance meter, the digital resistance meter is used for an A / D module, the A / D module is used to convert the resistance value of the hydrogel sensor into a digital value transmitted to the controller through the RS485 protocol, the controller is connected to the driver, the driver is connected to the motor, and the driver controls the movement of the software structure by driving the motor to operate; The preparation process of the hydrogel sensor comprises: The acrylamide powder was dissolved in distilled water, and dissolved under ultrasonic oscillation at 25°C for 5 minutes to form an aqueous solution, and then 0.2 g of PEDOT:PSS was added to the aqueous solution. After the solution was evenly mixed, a crosslinker, an initiator and a catalyst were added, and then ultrasonically dissolved in an ice bath for ten minutes to obtain an AM / PEDOT:PSS precursor solution; the prepared precursor solution was poured into a customized polytetrafluoroethylene plate mold, and reacted in an oven at 60°C for 1 hour to obtain a PAM / PEDOT:PSS hydrogel; The PAM / PEDOT:PSS hydrogel was cut into a preset shape using a polytetrafluoroethylene plate mold; Connecting the cut hydrogel to a lead wire to obtain the hydrogel sensor; The cross-linking agent is 2-mercaptobenzoic acid, the initiator is ammonium sulfate, and the catalyst is tetramethylethylenediamine; An upper disc is arranged at one end of the upper structure away from the lower structure, a middle disc is arranged in the intermediate transition structure, and a lower disc is arranged at one end of the lower structure away from the upper structure; wherein, The upper structure is provided with a first accommodating cavity and a first hollow cylinder penetrating the upper structure in the longitudinal direction thereof, a first hydrogel sensor is embedded in the first accommodating cavity, a first fishing line for controlling the extension and bending of the upper structure is passed through the first hollow cylinder, a second accommodating cavity and a second hollow cylinder penetrating the lower structure in the longitudinal direction thereof is provided inside the lower structure, a second hydrogel sensor is embedded in the second accommodating cavity, and a second fishing line for controlling the extension and bending of the lower structure is provided inside the second hollow cylinder; The lead wire of the first hydrogel sensor passes through the upper disk and is led out from the upper disk; one end of the first fishing line is led out from the upper disk, and the other end passes through the middle disk and is tied, and then sealed with glue; one end of the second fishing line passes through the middle disk and the upper structure, and passes through the upper disk, and is led out from the upper disk; the other end passes through the lower disk and is tied, and then sealed with glue; the lead wire of the second hydrogel sensor is led out from the middle disk; The data calibration process of the hydrogel sensor includes: After the hydrogel sensor is integrated into the soft robot, a digital resistance meter is used to measure the resistance change of the hydrogel sensor, and the resistance change data is recorded and the fitting data is analyzed through a python program. At the same time, the state of the soft robot is captured in real time, and the angle change of the soft robot is measured; While the soft robot is being driven by a motor, the bending angle of the soft structure and the resistance value of the hydrogel sensor are measured synchronously to perform data analysis and obtain the corresponding relationship between the resistance value and the bending angle.

2. The self-sensing soft robot according to claim 1, characterized in that: There are three first accommodating cavities and three second accommodating cavities, each of which is respectively embedded with a first hydrogel sensor, and each of which is respectively embedded with a second hydrogel sensor; there are three first hollow cylinders and three second hollow cylinders, each of which is respectively penetrated with a first fishing line, and each of which is respectively penetrated with a second fishing line.

3. The self-sensing soft robot according to claim 1, characterized in that: The length of the first accommodating cavity is 2 mm longer than the length of the first hydrogel sensor, so that after the first hydrogel sensor is installed, the first accommodating cavity is sealed by a cover to seal the first hydrogel sensor, and each cover is provided with a hole for the sensor lead to pass through; The length of the second accommodating cavity is 2 mm longer than the length of the second hydrogel sensor, so that after the second hydrogel sensor is installed, the second accommodating cavity is sealed by a cover to seal the second hydrogel sensor, and each cover is provided with a hole for the sensor lead to pass through.

4. The self-sensing soft robot according to claim 1, characterized in that: When the software robot performs data communication, the RS485 protocol is used to transmit communication data.

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