Body force position sensing soft robotic arm driven by helical artificial muscle and manufacturing method

Abstract

The application discloses a body force position sensing soft robot arm driven by a spiral artificial muscle and a manufacturing method. The robot arm comprises a robot arm body, a driving module, a sensing module and an electronic device module. The driving module comprises a plurality of electric heating driving spiral artificial muscles arranged along the circumference of the robot arm body. Each spiral artificial muscle is arranged along the axial direction of the robot arm body. The sensing module comprises a stretching sensor for monitoring the position state of the soft robot arm in real time, a tactile sensor for monitoring the contact force of the end of the soft robot arm in real time and a temperature sensor for monitoring the temperature of the spiral artificial muscle in real time. The electronic device module is installed at the head end of the robot arm body and is electrically connected with the driving module and the sensing module. The application integrates temperature, posture and tactile sensing technologies, and significantly improves the intelligentization and self-adaptive capacity of the soft robot arm.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of soft robotic arms, and particularly relates to a body force and position sensing soft robotic arm driven by a spiral artificial muscle and a manufacturing method. BACKGROUND

[0002] Soft robots are inspired by flexible creatures and have significant advantages in safety and adaptability. These robots have the characteristics of interactive safety, compact size, body compliance and deformation, and can perform various complex tasks including handling fragile objects, exploring unknown environments and performing medical operations. In order to realize the unique motion of soft robots, actuators are key components. Various flexible driving methods such as pneumatic, cable, dielectric elastomer and shape memory alloy have been applied in soft robots.

[0003] Traditional pneumatic and tendon-driven methods have limitations in miniaturization and flexibility, while dielectric elastomer driving methods face harsh driving conditions and shorter service life. As a new type of artificial muscle, spiral artificial muscle actuators can provide high energy density driving by twisting polymer fibers into spiral spring shapes. These features make it possible to develop small, multi-sensing, cable-free and long-life soft robots.

[0004] However, existing spiral artificial muscle driven soft robots face many challenges in practical applications, especially in terms of body sensing and operation ability. Due to the lack of real-time sensing of its own posture, position and deformation, the robot cannot effectively adjust itself in a complex environment, resulting in limited ability to perform fine operations and multi-degree-of-freedom coordinated motion. In addition, the existing sensing system is independent of the driver, making it difficult to provide sufficient feedback for real-time adjustment. Although traditional sensors can sense the external environment, they cannot effectively reflect the internal state of the robot, thereby affecting its precise control ability in complex tasks.

[0005] The requirements of soft robots driven by spiral artificial muscles are particularly prominent in temperature, position and tactile perception. First, temperature perception is essential for the closed-loop control of spiral artificial muscles, as its driving relies on the thermal expansion of polymer fibers. However, the size of spiral artificial muscles is small, and traditional temperature sensors are difficult to make stable contact with their surface, resulting in inaccurate measurement results. Second, position perception is crucial for the motion control of soft robots. However, due to the nonlinear characteristics of spiral artificial muscles and their flexible structure, it is difficult to directly obtain position information. Current solutions mostly rely on external sensors, which not only increase system complexity, but also may reduce accuracy. Finally, in terms of tactile perception, due to the large and easily deformable contact area of soft robots, traditional tactile sensors often cannot be compatible with flexible actuators. This limitation affects the interaction ability of robots with the outside world, and thus restricts their wide application in complex environments. SUMMARY

[0006] In view of the defects of the prior art in the integration of position perception and contact perception of soft robotic arms, the present application provides a body force and position perception soft robotic arm driven by spiral artificial muscles and a manufacturing method. The present application not only realizes the integration of position perception and contact perception of soft robotic arms, but also adds temperature self-perception function to the driven artificial muscles to improve the intelligence and adaptive ability of the system.

[0007] The technical solution adopted by the present application is:

[0008] One, a body force and position perception soft robotic arm driven by spiral artificial muscles

[0009] The soft robotic arm comprises:

[0010] A robotic arm body;

[0011] A driving module comprising a plurality of electrothermal driving spiral artificial muscles arranged along the circumference of the robotic arm body, each spiral artificial muscle being arranged along the axial direction of the robotic arm body;

[0012] A perception module comprising a stretch sensor for real-time monitoring of the pose state of the soft robotic arm, a tactile sensor for real-time monitoring of the contact force at the end of the soft robotic arm, and a temperature sensor for real-time monitoring of the temperature of the spiral artificial muscle;

[0013] An electronic device module installed at the leading end of the robotic arm body and electrically connected to the driving module and the perception module.

[0014] Specifically, the driving module realizes the driving of the soft robotic arm to perform two-degree-of-freedom bending motion by independently controlling the electrothermal driving contraction of each spiral artificial muscle.

[0015] Preferably, the spiral artificial muscle adopts an artificial muscle spirally formed by winding a nylon polymer fiber with a metal nickel wire through a winding device.

[0016] Specifically, the stretch sensor mainly consists of a plurality of macro-bent optical fibers arranged along the circumference of the mechanical arm body at intervals, each macro-bent optical fiber is arranged along the axial direction of the mechanical arm body, and the macro-bent optical fiber is connected with the mechanical arm body; the number of the macro-bent optical fibers is the same as that of the spiral artificial muscles and is arranged in a corresponding and symmetrical manner, the output light signal of each macro-bent optical fiber serves as a pose signal, by monitoring the light power loss of the pose signal in real time, the pose state of the soft robotic arm can be monitored in real time; the tactile sensor adopts a soft optical fiber, the soft optical fiber is coaxially arranged in the center of the mechanical arm body, the output light signal of the soft optical fiber serves as a contact force signal, by monitoring the real-time light intensity of the contact force signal in real time, the contact force of the end of the soft robotic arm can be monitored in real time; the macro-bent optical fiber and the soft optical fiber are electrically connected with the electronic device module.

[0017] Specifically, the number of the temperature sensors is the same as that of the spiral artificial muscles and corresponds to each other; the temperature sensor adopts a power monitoring chip, and the power monitoring chip is integrated in the electronic device module, the output voltage and current signals of each power monitoring chip serve as the temperature signals of the corresponding spiral artificial muscle.

[0018] Specifically, the electronic device module comprises:

[0019] The perception unit is configured to receive a plurality of real-time pose signals and a real-time contact force signal, convert each signal into a voltage signal through a transimpedance amplifier, and then convert the voltage signal into a digital signal through an analog-to-digital converter to obtain a plurality of real-time pose digital signals and a real-time contact force digital signal.

[0020] The driving unit comprises a plurality of driving circuits, the number of the driving circuits is the same as that of the spiral artificial muscles and corresponds to each other, the driving circuit adopts a power amplification circuit, and each driving circuit is integrated with a power monitoring chip as a temperature sensor, each driving circuit is electrically connected with the corresponding spiral artificial muscle.

[0021] The single-chip microcomputer is electrically connected with the output ends of the perception unit and the output ends of the temperature sensors at the input end, is communicatively connected with the upper computer at the communication end, and is electrically connected with the control ends of the driving circuits at the output end.

[0022] Further, the electronic device module further comprises a separated multi-layer PCB card mainly composed of five-layer PCB cards connected by board-to-board connectors; the five-layer PCB cards are respectively a wiring board, a sensing board, a driving board, a main control board and a power supply board, the sensing board, the driving board, the main control board and the power supply board are respectively integrated with a sensing unit, a driving unit and a single-chip microcomputer, the wiring board is used for switching signals, and the power supply board is used for power supply.

[0023] Preferably, the mechanical arm body comprises end caps, an arm body, fiber connectors and a snap-on ring; each end of the arm body is arranged with an end cap, the arm body is internally provided with a spiral artificial muscle array, each spiral artificial muscle is arranged along the axial direction of the arm body and embedded in the inside of the arm body; the outer side of the arm body is provided with a macro-bending fiber array, and a soft optical fiber is arranged at the center of the arm body; the end cap arranged at the end of the arm body is used for connecting external equipment; the outer side of the end cap arranged at the head of the arm body is sleeved with a snap-on ring, a plurality of through holes are formed in the snap-on ring, and a fiber connector is arranged in each through hole; the end of the macro-bending fiber passes through the fiber connector and is connected with an infrared emitter tube or a photodiode, and the infrared emitter tube and the photodiode are electrically connected with the electronic device module; the two ends of each spiral artificial muscle are connected with two end caps respectively; each macro-bending fiber is connected with the arm body; and the snap-on ring is connected with the electronic device module.

[0024] Preferably, the arm body is made of silica gel material, the arm body adopts a columnar structure with a clover-shaped cross section, the columnar structure has three independent lobe cavities arranged uniformly in the circumferential direction, and one spiral artificial muscle is arranged in each independent lobe cavity along the axial direction, and the three spiral artificial muscles form the spiral artificial muscle array.

[0025] Further, the driving module further comprises a connecting ring, and one connecting ring is connected to the two ends of each spiral artificial muscle; a through groove is formed in the end cap, the length of the through groove is less than the diameter of the connecting ring, the end of the spiral artificial muscle passes through the through groove and is connected with the connecting ring, and the connecting ring abuts against the end cap.

[0026] II. A manufacturing method for the body force position sensing soft robotic arm

[0027] The manufacturing method comprises the following steps:

[0028] S1) using a winding device to spiral form nylon polymer fibers and metal nickel wires to obtain spiral artificial muscles, and pouring paraffin on the surface of each spiral artificial muscle to obtain spiral artificial muscles subjected to protection treatment;

[0029] S2) placing a plurality of spiral artificial muscles subjected to protection treatment and two end caps in a mold, injecting silica gel, and taking out the arm body installed with the driving module from the mold after solidification;

[0030] S3) installing a plurality of macro-bent optical fibers in corresponding installation grooves on the surface of the arm body;

[0031] S4) preparing a polyurethane waveguide, after coating a silicone rubber material on the surface of the polyurethane waveguide, obtaining a soft optical fiber; installing the soft optical fiber on the central hole of the arm body;

[0032] S5) electrically connecting each spiral artificial muscle with an electronic device module, and electrically connecting the macro-bent optical fiber and the soft optical fiber with the electronic device module, to obtain the soft robotic arm.

[0033] The beneficial effects of the present application are:

[0034] The present application significantly improves the intelligence and self-adaptive ability of the soft robotic arm by integrating temperature, attitude and tactile perception technologies. The temperature perception function ensures the stability of the driving system, the macro-bent optical fiber technology combined with neural networks realizes high-precision position and attitude perception, and the soft optical fiber technology provides effective contact perception, enhancing the flexibility control and object manipulation ability of the robot. In addition, through the distributed electronic device design, the system decoupling is optimized, the flexibility, stability and reliability are improved, making it more feasible to apply in extreme environments. The overall manufacturing process is simple and accurate, providing higher precision and reliability, laying a foundation for the wide application of soft robotic arms in medical, automation and other fields. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 It is a schematic diagram of a soft robotic arm driven by spiral artificial muscles and having body force and position perception ability;

[0036] Figure 2 It is an exploded view schematic diagram of a soft robotic arm driven by spiral artificial muscles and having body force and position perception ability;

[0037] Figure 3 It is a schematic diagram of a soft robotic arm manufacturing mold;

[0038] Figure 4 It is a driving and temperature perception hardware circuit schematic diagram of the second layer PCBA board;

[0039] Figure 5 It is a hardware schematic diagram of the optical fiber perception signal acquisition and processing system of the third layer PCBA board.

[0040] In the figure, 100, drive module, 110, spiral artificial muscle, 120, connecting ring; 200, perception module, 210, macro-bending optical fiber, 220, soft optical fiber; 300, mechanical arm body, 310, end cover, 320, arm body, 330, optical fiber connector, 340, buckling snap ring; 400, electronic device module, 410, shell, 420, separate multi-layer PCB card; 500, mold, 510, locking cover, 520, lower mold, 530, upper mold. DETAILED DESCRIPTION

[0041] The application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0042] The first aspect of the application provides a body force position perception soft robot arm driven by a spiral artificial muscle. The soft robot arm of the application is driven by a plurality of spiral artificial muscles, provides power through the Joule heating principle, and can realize high-precision two-degree-of-freedom bending motion. Through the integration of self-perception technology, the soft robot arm can not only perceive the temperature change and attitude change of the driver in real time, but also can make instant feedback to the modulus difference and pressure change of the external contact object, so as to realize more accurate and stable operation and control. This integrated scheme provides more possibilities for the application of soft robot arms in complex environments, especially in tasks requiring high flexibility and high perception capability, and can play a greater advantage.

[0043] As shown in Figure 1 The soft robot arm of the application comprises:

[0044] A mechanical arm body 300;

[0045] A drive module 100 comprising a plurality of electrothermal drive type spiral artificial muscles arranged uniformly along the circumference of the mechanical arm body 300, each spiral artificial muscle being arranged along the axial direction of the mechanical arm body 300; the drive module 100 provides power through the heating shrinkage principle of the spiral artificial muscle, and drives the soft robot arm to realize high-precision two-degree-of-freedom bending motion;

[0046] A perception module 200 comprising a stretch sensor for monitoring the pose state of the soft robot arm in real time, a tactile sensor for monitoring the contact force at the end of the soft robot arm in real time, and a temperature sensor for monitoring the temperature of the spiral artificial muscle during work in real time;

[0047] An electronic device module 400 installed at the head end of the mechanical arm body 300, electrically connected with the drive module 100 and the perception module 200 respectively, for driving and controlling the soft robot arm.

[0048] Specifically, the spiral artificial muscle adopts an artificial muscle spirally formed by winding a nylon polymer fiber and a metal nickel wire through a winding device, and the driving module 100 realizes the two-degree-of-freedom bending motion of the soft robotic arm by independently controlling the electro-thermal driving contraction of each spiral artificial muscle. The spiral artificial muscle deforms under the action of an electric signal, provides flexible and efficient driving force and responds to the needs of different loads. Among them, the electro-thermal driving contraction refers to the fact that the current causes the spiral artificial muscle to heat up, thereby causing thermal contraction.

[0049] Preferably, the spiral artificial muscle is made by a composite twisting process.

[0050] Specifically, as shown in Figure 2 The stretching sensor mainly consists of a plurality of macro-bending optical fibers 210 uniformly arranged along the circumference of the mechanical arm body 300. Each macro-bending optical fiber 210 is arranged along the axial direction of the mechanical arm body 300, and the macro-bending optical fiber 210 is connected to the mechanical arm body 300. The number of macro-bending optical fibers 210 is the same as that of spiral artificial muscles and is arranged symmetrically one-to-one. The output light signal of each macro-bending optical fiber 210 serves as a pose signal. By monitoring the optical power loss of the pose signal in real time, the pose state of the soft robotic arm can be monitored in real time. The pose state includes displacement and / or bending state.

[0051] Specifically, the number of macro-bending optical fibers 210 is the same as that of spiral artificial muscles and is arranged symmetrically one-to-one, which means that the corresponding macro-bending optical fiber 210 and spiral artificial muscle are symmetrically arranged on both sides of the axis of the mechanical arm body 300.

[0052] Specifically, the tactile sensor adopts a soft optical fiber 220, which is coaxially arranged in the center of the mechanical arm body 300. The output light signal of the soft optical fiber 220 serves as a contact force signal. By monitoring the real-time light intensity of the contact force signal in real time, the contact force of the end of the soft robotic arm can be monitored in real time. The macro-bending optical fiber 210 and the soft optical fiber 220 are electrically connected to the electronic device module 400.

[0053] Specifically, the number of temperature sensors is the same as that of spiral artificial muscles and one-to-one correspondence. The temperature sensor detects the temperature of its corresponding spiral artificial muscle based on the thermistor effect.

[0054] Specifically, as shown in Figure 4As shown, the temperature sensor adopts a power monitoring chip, which is integrated in the driving circuit of the corresponding spiral artificial muscle in the electronic device module 400. The output voltage and current signals of each power monitoring chip serve as the temperature signals of the corresponding spiral artificial muscle. The resistance of the spiral artificial muscle can be obtained according to the output voltage and current, and since the resistance of the spiral artificial muscle is related to the temperature, the temperature can be calculated according to the resistance. By using the temperature sensor to monitor the resistance change of the metal nickel wire closely combined with the artificial muscle driving unit in real time, the real-time change of the driving temperature can be accurately obtained, thereby ensuring the stability and accurate control of the driving system.

[0055] Specifically, the electronic device module 400 includes a sensing unit, a driving unit, and a single-chip microcomputer.

[0056] The sensing unit is configured to receive a plurality of real-time pose signals and a real-time contact force signal, convert each signal into a voltage signal through a transimpedance amplifier, and then convert the voltage signal into a digital signal through an analog-to-digital converter to obtain a plurality of real-time pose digital signals and a real-time contact force digital signal.

[0057] The driving unit includes a plurality of driving circuits, the number of the driving circuits is the same as the number of the spiral artificial muscles and each driving circuit corresponds to one spiral artificial muscle. Each driving circuit adopts a power amplifier circuit, and a power monitoring chip is integrated in each driving circuit as a temperature sensor. Each driving circuit is electrically connected to the corresponding spiral artificial muscle. The driving circuit can control the input voltage of the corresponding spiral artificial muscle according to the real-time pulse control signal received by itself.

[0058] The single-chip microcomputer is electrically connected to the output end of the sensing unit and the output end of each temperature sensor, and is in communication connection with the upper computer. The output end of the single-chip microcomputer is electrically connected to the control end of each driving circuit. The single-chip microcomputer is configured to receive the real-time pose digital signals and the real-time contact force digital signals from the sensing unit, receive the real-time temperature signals of the corresponding spiral artificial muscles from each temperature sensor, and generate a plurality of real-time pulse control signals according to the real-time feedback information received from the upper computer. The number of the real-time pulse control signals is the same as the number of the driving circuits of the spiral artificial muscles and each real-time pulse control signal corresponds to one driving circuit of the spiral artificial muscle. Finally, each real-time pulse control signal is sent to the corresponding driving circuit of the spiral artificial muscle. The single-chip microcomputer part can ensure that the soft robot arm can be adaptively adjusted according to the real-time sensing data to meet various complex task requirements.

[0059] Further, the upper computer obtains the real-time feedback information by processing the real-time sensing signals through a control algorithm.

[0060] In specific implementation, the communication end of the single-chip microcomputer can be connected with the upper computer in a manner of real-time data transmission and control instruction issuing through a serial port and the MicroROS Agent of the upper computer.

[0061] Further, each power amplification circuit controls the input voltage of the corresponding spiral artificial muscle through two parallel NMOS tubes.

[0062] Optionally, as shown in Figure 4 , the output current and voltage of the artificial muscle are obtained through the power monitoring chip, and are transmitted to the subsequent single-chip microcomputer to obtain the temperature information of the artificial muscle, so as to ensure stable driving.

[0063] Optionally, as shown in Figure 5 , the sensing unit uses a light-emitting diode to generate infrared light with a wavelength of 875 nm, the infrared light is received by a photodiode via an optical fiber, and the photodiode photocurrent signal is converted into a voltage signal by a transimpedance amplifier, and the voltage signal is converted into a digital signal by an analog-to-digital conversion chip and transmitted to the subsequent system for analysis.

[0064] Specifically, the electronic device module 400 further includes a separated multi-layer PCB card 420, which is mainly composed of five layers of PCB cards connected by board-to-board connectors; the five layers of PCB cards are respectively a wiring board, a sensing board, a driving board, a main control board and a power supply board, and the sensing board, the driving board, the main control board and the power supply board are respectively integrated with a sensing unit, a driving unit and a single-chip microcomputer; the wiring board is used for adapting signals, and the power supply board is used for power supply.

[0065] Further, the power supply board can convert 12V DC voltage into 3.3V and 5V for use by all the cards.

[0066] The five layers of cards are separated from each other and connected by board-to-board connectors to ensure functional separation and improve the reliability of the overall hardware system. In the electronic device module 400, the electronic devices are distributed on different PCB boards according to functions, and are distributedly arranged inside the soft arm, so as to realize decoupling of each subunit. This design not only improves the flexibility and stability of the system, but also provides feasibility for its application in extreme environments.

[0067] In specific implementation, the board-to-board connectors can be pins. That is, the board cards are physically and electrically connected through pins. 2 C protocol to ensure efficient and stable operation of the system, while ensuring real-time data and system robustness.

[0068] In specific implementation, the board-to-board connectors can be pins. That is, the board cards are physically and electrically connected through pins.

[0069] Specifically, the mechanical arm body 300 comprises an end cover 310, an arm body 320, a fiber connector 330 and a snap ring 340; the arm body 320 is provided with an end cover 310 at each end, the arm body 320 is internally provided with an array of spiral artificial muscles, each spiral artificial muscle is arranged along the axial direction of the arm body 320 and embedded in the arm body 320; the radial outer side of the arm body 320 is provided with an array of macro-bending optical fibers, and a soft optical fiber 220 is arranged at the center of the arm body 320; the end cover 310 arranged at the end of the arm body 320 is used for connecting external equipment; the end cover 310 arranged at the head of the arm body 320 is sleeved with a snap ring 340, a plurality of through holes are formed in the snap ring 340, and one fiber connector 330 is arranged in each through hole; the end of the macro-bending optical fiber 210 is connected with an infrared emitter tube or a photodiode through the fiber connector 330, and the infrared emitter tube and the photodiode are electrically connected with the wiring board in the electronic device module 400; the two ends of each spiral artificial muscle are connected with two end covers 310 respectively; each macro-bending optical fiber 210 is connected with the arm body 320; and the snap ring 340 is connected with the electronic device shell 410 in the electronic device module 400.

[0070] Preferably, the array of spiral artificial muscles arranged in the arm body 320 is implemented as follows: the arm body 320 is made of silica gel material, the arm body 320 adopts a three-leaf clover-shaped cross-section columnar structure, the columnar structure has three independent lobe cavities arranged uniformly in the circumferential direction, and one spiral artificial muscle is arranged in each independent lobe cavity in the axial direction, and the three spiral artificial muscles form the array of spiral artificial muscles. The three-leaf clover-shaped cross-section design of the arm body 320 enables the soft robot arm to better couple the driving module 100 and the sensing module 200, and the mechanical arm body 300 has good flexibility and operability to adapt to complex working environments.

[0071] Preferably, the two ends of each spiral artificial muscle are connected with two end covers 310 respectively, and the implementation is as follows: the driving module 100 further comprises a connecting ring 120, and the two ends of each spiral artificial muscle are connected with one connecting ring 120 respectively; a through slot is formed in the end cover 310, the length of the through slot is less than the diameter of the connecting ring 120, and the end of the spiral artificial muscle is connected with the connecting ring 120 after penetrating through the through slot.

[0072] Preferably, each macro-bending optical fiber 210 is connected with the arm body 320, and the implementation is as follows: a plurality of mounting grooves are formed on the surface of the arm body 320 and arranged uniformly in the circumferential direction of the arm body 320, each mounting groove is arranged in the axial direction of the arm body 320, the number of the mounting grooves is the same as that of the macro-bending optical fibers 210 and corresponds to the macro-bending optical fibers 210 one by one, the macro-bending optical fibers 210 are arranged in the corresponding mounting grooves, and the macro-bending optical fibers 210 can be fixed by adhesion or the like.

[0073] Preferably, the implementation of the method of inserting a soft optical fiber 220 through the center of the arm body 320 is as follows: a central hole is provided inside the arm body 320, and the soft optical fiber 220 is inserted into the central through hole. The soft optical fiber 220 can be fixed by means of interference fit or other methods.

[0074] Optionally, the end cap 310 is connected to the arm body 320 in the following manner: the end cap 310 is embedded in the annular groove at the end of the arm body 320 and is interference-fitted with the annular groove.

[0075] Furthermore, the arm body 320 is also provided with several cable mounting holes for installing connecting cables. For example, cables for electrically connecting the end of each spiral artificial muscle to the terminal block, and cables for electrically connecting the infrared emitter at the end of the flexible optical fiber 220 to the terminal block, etc.

[0076] A second aspect of the present invention provides a method for manufacturing the above-described body force-sensing soft robotic arm.

[0077] The manufacturing method of this invention includes the following steps:

[0078] S1) Using a winding device, nylon polymer fibers and nickel wires are spirally formed to obtain spiral artificial muscles. Paraffin wax is poured onto the surface of each spiral artificial muscle to protect the spiral artificial muscles, thus obtaining protected spiral artificial muscles.

[0079] S2) Place multiple protected spiral artificial muscles and two end caps 310 inside the mold 500, inject silicone, and after curing, remove the arm body 320 with the drive module 100 installed from the mold 500.

[0080] like Figure 3 As shown, mold 500 includes upper mold 530, lower mold 520 and locking cover 510;

[0081] S3) Install multiple macro-bend optical fibers 210 into the corresponding mounting slots on the surface of the arm body 320;

[0082] S4) Fabricate a polyurethane waveguide, coat the surface of the polyurethane waveguide with silicone rubber material to obtain a soft optical fiber 220; install the soft optical fiber 220 on the center hole of the arm body 320.

[0083] S5) Connect each spiral artificial muscle to the electronic device module 400 via a cable, and connect the macro-bending optical fiber 210 and the soft optical fiber 220 to the electronic device module 400 via a cable to obtain a soft robotic arm.

[0084] Specific embodiments of the present invention are as follows:

[0085] Example

[0086] The embodiment provides a soft robot arm with a columnar silica gel structure in the shape of a three-leaf clover, and three spiral artificial muscles embedded in the soft robot arm. Each spiral artificial muscle is provided with a cable mounting hole on one side, which is used for arranging a connecting cable corresponding to the spiral artificial muscle. The center of the robot arm body 300 is provided with a center hole for arranging a tactile sensor, and one side of the center hole is provided with a cable mounting hole for arranging a connecting cable corresponding to the tactile sensor.

[0087] The main control circuit part includes a wiring board, a sensing board, a driving board, a main control board and a power supply board. The wiring board is connected with various sensors and spiral artificial muscles, the sensing board is responsible for processing sensor data and transmitting to the main control board, and the driving board receives the control signal of the main control board and transmits it to the driver part. According to the real-time data fed back by the sensor, the main control board generates a driving signal through the control algorithm in the upper computer, accurately adjusts the output force of the driver part, and realizes the efficient and accurate motion control of the soft robot arm. The main control circuit part ensures that the soft robot arm can be adaptively adjusted according to the real-time sensing data to meet various complex task requirements.

[0088] In the embodiment, the preparation method of the soft robot arm is specifically as follows:

[0089] S1) using a winding device to spiral form nylon polymer fibers and metal nickel wires to obtain spiral artificial muscles, and protecting the spiral artificial muscles by casting paraffin on the surface of each spiral artificial muscle to obtain spiral artificial muscles after protection; during the protection process, the paraffin forms a protective shell after solidifying on the surface of the spiral artificial muscle, which can effectively prevent the silica gel from solidifying in the spiral gap of the spiral artificial muscle and affecting the driving effect;

[0090] S2) placing a plurality of spiral artificial muscles after protection in a mold, mixing Ecoflex 00-50 two-component silica gel and removing bubbles with a vacuum pump, and then injecting the mold by means of point gluing casting to obtain an arm body 320 provided with a driving module 100;

[0091] As shown in Figure 5 The pouring mold is divided into two parts, and the two ends are respectively provided with two end covers 310 with through holes in the center. After clamping and locking, the steel rod is inserted through the center through holes of the end covers 310 and the mold, and then poured through the pouring hole.

[0092] The point gluing casting mode is to slowly inject the mixed silica gel into the mold until it overflows. Then the mold is placed in a 50℃ oven, and the silica gel is completely cured. After curing, the mold is disassembled, the steel rod is removed and the cable welding is completed, and the flexible robot arm body composed of the driving module 100, the arm body 320 and the end cover 310 is obtained.

[0093] S3) bending one optical fiber into several rings with the same circumference to obtain a macro-bent optical fiber 210; installing the plurality of macro-bent optical fibers 210 in the corresponding installation slots on the surface of the arm body 320 by adhesion, and electrically connecting the input end and the output end of each macro-bent optical fiber 210 with the infrared emitter tube and the photodiode, respectively; and mounting the infrared emitter tube and the photodiode on the snap ring 340;

[0094] In the embodiment of the application, the optical fiber CK30 with a diameter of 1 mm is bent into seven rings with a circumference of 60 mm to obtain a macro-bent optical fiber 210.

[0095] In the embodiment of the application, the model of the device connected with the macro-bent optical fiber 210 is specifically: an infrared emitter tube IR204-A and a photodiode PD204-6B / L3.

[0096] S4) using silica gel to make a soft optical fiber mold with a hollow of 3 mm, fixing a photodiode at one end of the soft optical fiber mold, mixing polyurethane raw materials and performing vacuum treatment, then slowly injecting the mixture treated by vacuum into the soft optical fiber mold through a dispensing machine until the polyurethane overflows, inserting an infrared emitter tube at the other end of the soft optical fiber mold and fixing it; after the polyurethane is cured, taking out the polyurethane waveguide from the soft optical fiber mold, and coating a low-refractive silica rubber material as an outer shell layer on the surface of the polyurethane waveguide; after the outer shell layer is cured, a soft optical fiber 220 is obtained; and the soft optical fiber 220 is installed through the following process:

[0097] The end of the soft optical fiber 220 provided with the infrared emitter tube is taken as the terminal end, the soft optical fiber 220 is passed through the center hole of the arm body 320, the infrared emitter tube at the terminal end of the soft optical fiber 220 is connected with one end of the cable, the other end of the cable is passed through the cable installation hole arranged on one side of the center hole and connected with the wiring board in the electronic device module 400, and the photodiode at the head end of the soft optical fiber 220 is electrically connected with the wiring board in the electronic device module 400 through the cable.

[0098] In the embodiment, the polyurethane is mixed with polyurethane VytaFlex 20 raw materials at a ratio of 1:1.

[0099] In the embodiment of the application, the model of the device connected with the soft optical fiber 220 is specifically: an infrared emitter tube TSHA6203 and a photodiode SFH 213FA.

[0100] S5) connecting the two ends of each spiral artificial muscle with the wiring board in the electronic device module 400 through a cable, and connecting the corresponding infrared emitter tube and photodiode of each macro-bent optical fiber 210 with the wiring board in the electronic device module 400 through a cable, to obtain an assembled body force position sensing soft robotic arm.

[0101] The above shows and describes the basic principles, main features and advantages of the present application. It should be understood by those skilled in the art that the present application is not limited to the above embodiments, and the above embodiments and descriptions in the specification are only to illustrate the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application.

Claims

1. A proprioceptive force-sensing soft robotic arm driven by helical artificial muscles, characterized in that, include: Robotic arm body (300); The drive module (100) includes several electrothermal driven spiral artificial muscles arranged circumferentially along the main body of the robotic arm (300), and each spiral artificial muscle is arranged along the axial direction of the main body of the robotic arm (300). The sensing module (200) includes a stretching sensor for real-time monitoring of the pose state of the soft robotic arm, a tactile sensor for real-time monitoring of the contact force at the end of the soft robotic arm, and a temperature sensor for real-time monitoring of the temperature of the helical artificial muscle. The stretch sensor mainly consists of several macro-bent optical fibers (210) arranged circumferentially along the main body of the robotic arm (300). Each macro-bent optical fiber (210) is arranged along the axial direction of the main body of the robotic arm (300) and is connected to the main body of the robotic arm (300). The number of macro-bent optical fibers (210) is the same as that of the spiral artificial muscles and they are arranged symmetrically. The output light signal of each macro-bent optical fiber (210) serves as a pose signal. By monitoring the light power loss of the pose signal in real time, the pose state of the soft robotic arm can be monitored in real time. The tactile sensor uses a soft optical fiber (220). The soft optical fiber (220) is coaxially inserted through the center of the main body of the robotic arm (300). The output light signal of the soft optical fiber (220) serves as a contact force signal. By monitoring the real-time light intensity of the contact force signal in real time, the contact force at the end of the soft robotic arm can be monitored in real time. Both the macro-bent optical fiber (210) and the soft optical fiber (220) are electrically connected to the electronic device module (400). An electronic device module (400) is installed at the head end of the robotic arm body (300) and is electrically connected to the drive module (100) and the sensing module (200) respectively.

2. The body force-sensing soft robotic arm according to claim 1, characterized in that: The spiral artificial muscle is an artificial muscle formed by spiraling nylon polymer fibers and nickel wire. The drive module (100) drives the soft robotic arm to perform two-degree-of-freedom bending motion by independently controlling the electrothermal drive contraction of each spiral artificial muscle.

3. The body force-sensing soft robotic arm according to claim 1, characterized in that: The number of temperature sensors is the same as and corresponds to the number of spiral artificial muscles; the temperature sensors are power monitoring chips, which are integrated into the electronic device module (400), and the output signal of each power monitoring chip is used as the temperature signal of the corresponding spiral artificial muscle.

4. The body force-sensing soft robotic arm according to claim 1, characterized in that: The electronic device module (400) includes: The sensing unit is used to receive multiple real-time pose signals and one real-time contact force signal, and convert each signal into a voltage signal through a transimpedance amplifier, and then convert it into a digital signal through an analog-to-digital converter to obtain multiple real-time pose digital signals and one real-time contact force digital signal. The driving unit includes multiple driving circuits, the number of which is the same as and corresponds to the number of spiral artificial muscles. The driving circuits adopt power amplifier circuits, and each driving circuit integrates a power monitoring chip as a temperature sensor. Each driving circuit is electrically connected to the corresponding spiral artificial muscle. The microcontroller's input terminals are electrically connected to the output terminals of the sensing unit and each temperature sensor, respectively. Its communication terminal is connected to the host computer, and its output terminals are electrically connected to the control terminals of each drive circuit.

5. The body force-sensing soft robotic arm according to claim 4, characterized in that: The electronic device module (400) also includes a separate multilayer PCB board (420), which is mainly composed of five layers of PCB boards connected to each other via board-to-board connectors. The five layers of PCB boards are a wiring board, a sensing board, a driving board, a main control board, and a power board. The sensing board, driving board, main control board, and power board integrate a sensing unit, a driving unit, and a microcontroller, respectively. The wiring board is used to transfer signals, and the power board is used to supply power.

6. The body force-sensing soft robotic arm according to claim 1, characterized in that: The robotic arm body (300) includes an end cap (310), an arm body (320), an optical fiber connector (330), and a snap-fit ​​ring (340). An end cap (310) is arranged at each end of the arm body (320). A spiral artificial muscle array is disposed inside the arm body (320), with each spiral artificial muscle arranged along the axial direction of the arm body (320) and embedded inside. A macro-bent optical fiber array is disposed on the outside of the arm body (320), and a soft optical fiber (220) passes through the center of the arm body (320). The end cap (310) at the end of the arm body (320) is used to connect to external devices. 320) The end cap (310) at the head end is fitted with a snap ring (340) on the outside. The snap ring (340) has several through holes, and each through hole is fitted with an optical fiber connector (330). The end of the macro-bent optical fiber (210) passes through the optical fiber connector (330) and is connected to an infrared emitting tube or a photodiode. Both the infrared emitting tube and the photodiode are electrically connected to the electronic device module (400). The two ends of each spiral artificial muscle are connected to the two end caps (310) respectively. Each macro-bent optical fiber (210) is connected to the arm body (320). The snap ring (340) is connected to the electronic device module (400).

7. The body force-sensing soft robotic arm according to claim 6, characterized in that: The arm body (320) is made of silicone material and adopts a columnar structure with a clover-shaped cross section. The columnar structure has three independent leaf-shaped cavities evenly arranged along the circumference. Each independent leaf-shaped cavity has a spiral artificial muscle arranged along the axial direction. The three spiral artificial muscles form the spiral artificial muscle array.

8. The body force-sensing soft robotic arm according to claim 6, characterized in that: The drive module (100) also includes a connecting ring (120), with one connecting ring (120) connected to each end of each spiral artificial muscle; the end cap (310) has a through groove, and the end of the spiral artificial muscle passes through the through groove and connects to the connecting ring (120).

9. A method for manufacturing a body force-sensing soft robotic arm as described in any one of claims 1 to 8, characterized in that, Includes the following steps: S1) Using a winding device, nylon polymer fibers and nickel wires are spirally formed to obtain spiral artificial muscles. Paraffin wax is poured onto the surface of each spiral artificial muscle to obtain spiral artificial muscles with protective treatment. S2) Place multiple protected spiral artificial muscles and two end caps (310) inside the mold (500), inject silicone, and after curing, remove the arm body (320) with the drive module (100) installed from the mold (500). S3) Install multiple macro-bend optical fibers (210) in the corresponding mounting slots on the surface of the arm body (320); S4) Prepare a polyurethane waveguide, coat the surface of the polyurethane waveguide with silicone rubber material to obtain a soft optical fiber (220); install the soft optical fiber (220) on the center hole of the arm body (320); S5) Electrically connect each spiral artificial muscle to the electronic device module (400), and electrically connect the macro-bending optical fiber (210) and the soft optical fiber (220) to the electronic device module (400) to obtain the soft robotic arm.

Images