Body force position sensing soft mechanical arm driven by spiral artificial muscle and manufacturing method

Abstract

The invention discloses a body force position sensing soft mechanical arm driven by spiral artificial muscles and a manufacturing method. Comprising a robot arm body; the driving module comprises a plurality of electric heating driving type spiral artificial muscles which are arranged in the circumferential direction of the mechanical arm body at intervals, and each spiral artificial muscle is arranged in the axial direction of the mechanical arm body; the sensing module comprises a stretching sensor used for monitoring the posture state of the soft mechanical arm in real time, a touch sensor used for monitoring the contact force of the tail end of the soft mechanical arm in real time and a temperature sensor used for monitoring the temperature of the spiral artificial muscle in real time; the electronic device module is installed at the head end of the mechanical arm body and electrically connected with the driving module and the sensing module. By integrating the temperature, posture and touch sensing technology, the intelligence and self-adaptive capacity of the soft mechanical arm are remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of soft robotic arms, and particularly to a self-force and position sensing soft robotic arm driven by a helical artificial muscle and a manufacturing method thereof. Background Art

[0002] Soft robots have emerged inspired by flexible organisms and have significant advantages in terms of safety and adaptability. These robots have characteristics such as interactive safety, compact size, and compliant and deformable bodies, and can perform various complex tasks including manipulating fragile objects, exploring unknown environments, and performing medical operations. To achieve the unique movements of soft robots, actuators are key components. Multiple existing 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 short service lives. As an emerging artificial muscle, the helical artificial muscle actuator can provide high energy density driving by twisting polymer fibers into a helical spring shape. These characteristics make it possible to develop soft robots that are miniaturized, have multi-sensing capabilities, do not require cable connections, and have long service lives.

[0004] However, existing helical artificial muscle-driven soft robots face many challenges in practical applications, especially in terms of self-sensing and operation capabilities. Due to the lack of real-time sensing of their own postures, positions, and deformations, robots cannot effectively adjust themselves in complex environments, resulting in limited capabilities for fine operations and multi-degree-of-freedom coordinated movements. In addition, existing sensing systems are independent of the actuators and it is 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 capabilities in complex tasks.

[0005] The requirements for spiral artificial muscle-driven soft robots in terms of temperature, position, and tactile perception are particularly prominent. First, temperature perception is crucial for achieving closed-loop control of spiral artificial muscles because their actuation relies on the thermal expansion of polymer fibers. However, due to the small size of spiral artificial muscles, it is difficult for traditional temperature sensors to stably contact their surfaces, resulting in inaccurate measurement results. Second, position perception is essential for the motion control of soft robots. However, due to the non-linear characteristics of spiral artificial muscles and their flexible structures, it is difficult to directly obtain position information. Most current solutions rely on external sensors, which not only increases system complexity but also may reduce accuracy. Finally, in terms of tactile perception, since soft robots have large and deformable contact areas, traditional tactile sensors often cannot be compatible with flexible actuators. This limitation affects the robot's interaction ability with the outside world and thus restricts its wide application in complex environments. Summary of the Invention

[0006] Aiming at the defects in the integration of position perception and contact perception of soft robotic arms in the prior art, the present invention provides a self-force and position perception soft robotic arm driven by spiral artificial muscles and a manufacturing method thereof. The present invention not only realizes the integration of position perception and contact perception of the soft robotic arm but also adds a temperature self-perception function to the driving artificial muscles to improve the intelligence and adaptability of the system.

[0007] The technical solution adopted by the present invention is as follows:

[0008] I. A self-force and position perception soft robotic arm driven by spiral artificial muscles

[0009] The soft robotic arm includes:

[0010] A robotic arm body;

[0011] A driving module, including a plurality of electrothermal driving type spiral artificial muscles arranged at intervals along the circumferential direction of the robotic arm body, and each spiral artificial muscle is arranged along the axial direction of the robotic arm body;

[0012] A sensing module, including 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 spiral artificial muscle;

[0013] An electronic device module, installed at the head end of the robotic arm body and electrically connected to the driving module and the sensing module respectively.

[0014] Specifically, the driving module realizes driving 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 is an artificial muscle formed by spirally shaping a nylon polymer fiber and a nickel wire through a winding device.

[0016] Specifically, the stretching sensor mainly consists of a number of macro-bending optical fibers arranged at intervals in the circumferential direction of the main body of the robotic arm. Each macro-bending optical fiber is arranged along the axial direction of the main body of the robotic arm and is connected to the main body of the robotic arm; the number of macro-bending optical fibers is the same as that of the spiral artificial muscles and they are arranged symmetrically in correspondence. The output optical signal of each macro-bending optical fiber 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 tactile sensor uses a soft optical fiber, and the soft optical fiber is coaxially disposed at the center inside the main body of the robotic arm. The output optical 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 at the end of the soft robotic arm can be monitored in real time; both the macro-bending optical fibers and the soft optical fibers are electrically connected to the electronic device module.

[0017] Specifically, the number of temperature sensors is the same as that of the spiral artificial muscles and they are in correspondence; the temperature sensors use power monitoring chips, and the power monitoring chips are integrated in the electronic device module. The output voltage and current signals of each power monitoring chip serve as the temperature signal of the corresponding spiral artificial muscle.

[0018] Specifically, the electronic device module includes:

[0019] A sensing unit for receiving a plurality of real-time pose signals and a real-time contact force signal, converting each signal into a voltage signal through a transimpedance amplifier, and then converting it 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] A driving unit including a plurality of driving circuits. The number of driving circuits is the same as that of the spiral artificial muscles and they are in correspondence. The driving circuits use 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;

[0021] A single-chip microcomputer, whose input terminals are electrically connected to the output terminals of the sensing unit and the output terminals of each temperature sensor respectively, whose communication terminal is communicatively connected to the upper computer, and whose output terminals are electrically connected to the control terminals of each driving circuit respectively.

[0022] Further, the electronic device module further includes a separated multi-layer PCB board, which is mainly composed of a five-layer PCB board. The boards are connected by board-to-board connectors. The five-layer PCB boards 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 signal transfer, and the power supply board is used for power supply.

[0023] Preferably, the manipulator body includes an end cap, an arm body, an optical fiber connector, and a snap ring; an end cap is arranged at each end of the arm body. A spiral artificial muscle array is arranged inside the arm body. Each spiral artificial muscle is arranged along the axial direction of the arm body and embedded inside the arm body. A macro-bending optical fiber array is arranged outside the arm body, and a soft optical fiber passes through the center of the arm body. The end cap arranged at the end of the arm body is used to connect external devices; a snap ring is sleeved outside the end cap arranged at the head end of the arm body. A plurality of through holes are formed in the snap ring, and an optical fiber connector is installed in each through hole. The end of the macro-bending optical fiber passes through the optical fiber connector 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; both ends of each spiral artificial muscle are respectively connected to the two end caps; each macro-bending optical fiber is connected to the arm body; the snap ring is connected to the electronic device module.

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

[0025] Further, the driving module further includes a connecting ring. A connecting ring is connected to each end of each spiral artificial muscle; a through groove is formed in the end cap, and the length of the through groove is smaller than the diameter of the connecting ring. The end of the spiral artificial muscle passes through the through groove and is connected to the connecting ring, and the connecting ring abuts against the end cap.

[0026] II. A manufacturing method for the above-mentioned force-position sensing soft manipulator

[0027] The manufacturing method includes the following steps:

[0028] S1) Use a winding device to helically form a nylon polymer fiber and a metal nickel wire to obtain a spiral artificial muscle, and pour paraffin on the surface of each spiral artificial muscle to obtain a spiral artificial muscle with protective treatment;

[0029] S2) Place a plurality of spiral artificial muscles with protective treatment and two end caps inside a mold, inject silica gel, and after curing, take out the arm body installed with the driving module from the mold;

[0030] S3) Install multiple macro-bent optical fibers into the corresponding installation grooves on the surface of the arm body;

[0031] S4) Prepare a polyurethane waveguide. After coating a silicone rubber material on the surface of the polyurethane waveguide, a soft optical fiber is obtained; install the soft optical fiber on the central hole of the arm body;

[0032] S5) Electrically connect each helical artificial muscle to the electronic device module, and electrically connect the macro-bent optical fiber and the soft optical fiber to the electronic device module to obtain the soft robotic arm.

[0033] The beneficial effects of the present invention are as follows:

[0034] By integrating temperature, attitude, and tactile sensing technologies, the present invention significantly improves the intelligence and adaptability of the soft robotic arm. The temperature sensing function ensures the stability of the drive system. The combination of the macro-bent optical fiber technology and neural networks realizes high-precision position and attitude sensing, while the soft optical fiber technology provides effective contact sensing, enhancing the flexible control and object manipulation capabilities of the robot. In addition, through the distributed electronic device design, the system decoupling is optimized, improving flexibility, stability, and reliability, making it more feasible for applications in extreme environments. The overall manufacturing process is simple and precise, providing higher precision and reliability, laying a foundation for the wide application of the soft robotic arm in the fields of medical treatment, automation, etc. Description of the Drawings

[0035] Figure 1 Schematic diagram of a soft robotic arm driven by helical artificial muscles and having the ability of proprioceptive force and position sensing according to the present invention;

[0036] Figure 2 Exploded view schematic diagram of a soft robotic arm driven by helical artificial muscles and having the ability of proprioceptive force and position sensing;

[0037] Figure 3 Schematic diagram of the mold for manufacturing the soft robotic arm;

[0038] Figure 4 Schematic diagram of the drive and temperature sensing hardware circuit of the second-layer PCBA board;

[0039] Figure 5 Schematic diagram of the hardware principle of the acquisition and processing system for the optical fiber sensing signal of the third-layer PCBA board.

[0040] In the figure, 100 is the drive module, 110 is the helical artificial muscle, and 120 is the connecting ring; 200 is the sensing module, 210 is the macro-bending optical fiber, and 220 is the soft optical fiber; 300 is the main body of the robotic arm, 310 is the end cap, 320 is the arm body, 330 is the optical fiber connector, and 340 is the snap-in retaining ring; 400 is the electronic device module, 410 is the housing, and 420 is the separated multi-layer PCB board; 500 is the mold, 510 is the locking cover, 520 is the lower mold, and 530 is the upper mold. Detailed implementation manners

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

[0042] In the first aspect of the present invention, a body force and position sensing soft robotic arm driven by a helical artificial muscle is provided. The soft robotic arm of the present invention is driven by multiple helical artificial muscles, provides power through the Joule heating principle, and can achieve high-precision two-degree-of-freedom bending motion. Through the integrated self-sensing technology, the soft robotic arm can not only sense the temperature change and posture change of its own actuator in real time, but also make immediate feedback on the modulus difference and pressure change of the external contact object, so as to achieve more accurate and stable operation and control. This integrated solution provides more possibilities for the application of the soft robotic arm in complex environments, especially in tasks that require high flexibility and high sensing ability, and can play a greater advantage.

[0043] As Figure 1 shown, the soft robotic arm of the present invention includes:

[0044] The main body 300 of the robotic arm;

[0045] The drive module 100 includes a number of electrothermal drive type helical artificial muscles arranged at equal intervals in the circumferential direction of the main body 300 of the robotic arm, and each helical artificial muscle is arranged along the axial direction of the main body 300 of the robotic arm; the drive module 100 provides power through the principle of heat contraction of the helical artificial muscle, and drives the soft robotic arm to achieve high-precision two-degree-of-freedom bending motion;

[0046] The sensing module 200 includes a tensile 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 during operation;

[0047] The electronic device module 400 is installed at the head end of the main body 300 of the robotic arm, and is electrically connected to the drive module 100 and the sensing module 200 respectively, and is used to drive and control the soft robotic arm.

[0048] Specifically, the helical artificial muscle adopts an artificial muscle formed by helically shaping a nylon polymer fiber and a nickel wire through a winding device. The driving module 100 realizes the two-degree-of-freedom bending motion of the driven soft robotic arm by independently controlling the electrothermal driving contraction of each helical artificial muscle. The helical artificial muscle deforms under the action of an electrical signal, providing a flexible and efficient driving force and responding to the requirements of different loads. Among them, electrothermal driving contraction means that an electric current causes the helical artificial muscle to heat up, thereby causing thermal contraction.

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

[0050] Specifically, as Figure 2 shown, the stretch sensor mainly consists of a number of macro-bending optical fibers 210 evenly arranged at intervals along the circumference of the robotic arm body 300. Each macro-bending optical fiber 210 is arranged along the axis of the robotic arm body 300, and the macro-bending optical fiber 210 is connected to the robotic arm body 300; the number of macro-bending optical fibers 210 is the same as that of the helical artificial muscles and they are arranged symmetrically in a one-to-one correspondence. The output optical signal of each macro-bending optical fiber 210 is used as a pose signal. By real-time monitoring of the optical power loss of the pose signal, the pose state of the soft robotic arm can be monitored in real time, and the pose state includes displacement and / or bending state.

[0051] Specifically, the fact that the number of macro-bending optical fibers 210 is the same as that of the helical artificial muscles and they are arranged symmetrically in a one-to-one correspondence means that the corresponding macro-bending optical fiber 210 and helical artificial muscle are symmetrically arranged on both sides of the axis of the robotic arm body 300.

[0052] Specifically, the tactile sensor adopts a soft optical fiber 220. The soft optical fiber 220 is coaxially arranged inside the center of the robotic arm body 300. The output optical signal of the soft optical fiber 220 is used as a contact force signal. By real-time monitoring of the real-time optical intensity of the contact force signal, the contact force at the end of the soft robotic arm can be monitored in real time; both 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 the helical artificial muscles and they are in one-to-one correspondence. The temperature sensor detects the temperature of its corresponding helical artificial muscle based on the thermoresistance effect.

[0054] Specifically, as Figure 4As shown, the temperature sensor uses a power monitoring chip, which is integrated into the drive circuit corresponding to the 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 based on the output voltage and current. Since the resistance of the spiral artificial muscle is related to temperature, the temperature can be calculated according to its resistance. By using the temperature sensor to monitor the resistance change of the nickel wire closely combined with the artificial muscle drive unit in real time, the real-time change of the drive temperature can be accurately obtained, thus ensuring the stability and precise control of the drive system.

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

[0056] The sensing unit is used to receive multiple 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 it into a digital signal through an analog-to-digital converter to obtain multiple real-time pose digital signals and a real-time contact force digital signal.

[0057] The drive unit includes multiple drive circuits, the number of drive circuits is the same as and corresponds one-to-one to the number of spiral artificial muscles. The drive circuit uses a power amplifier circuit, and each drive circuit integrates a power monitoring chip as a temperature sensor. Each drive circuit is electrically connected to the corresponding spiral artificial muscle. The drive circuit can control the input voltage of the corresponding spiral artificial muscle according to the real-time pulse control signal it receives.

[0058] The single-chip microcomputer has its input end electrically connected to the output ends of the sensing unit and the output ends of each temperature sensor respectively, its communication end is communicatively connected to the host computer, and its output end is electrically connected to the control ends of each drive circuit respectively. The single-chip microcomputer is used to receive the real-time pose digital signal and the real-time contact force digital signal from the sensing unit, and receive the real-time temperature signal of the corresponding spiral artificial muscle from each temperature sensor. The real-time pose digital signal, the real-time contact force digital signal, and the real-time temperature signal form a real-time sensing signal. The single-chip microcomputer sends all the real-time sensing signals to the host computer, receives the real-time feedback information from the host computer, and generates multiple real-time pulse control signals according to the real-time feedback information. The number of real-time pulse control signals is the same as and corresponds one-to-one to the number of drive circuits of the spiral artificial muscle. Finally, the single-chip microcomputer sends each real-time pulse control signal to the drive circuit of the corresponding spiral artificial muscle respectively. The single-chip microcomputer part can ensure that the soft robotic arm can make adaptive adjustments according to the real-time sensing data to meet the requirements of various complex tasks.

[0059] Furthermore, after processing the real-time sensing signal through a control algorithm, the host computer obtains the real-time feedback information.

[0060] In specific implementation, the communication connection mode between the communication terminal of the single-chip microcomputer and the host computer can be: real-time data transmission and control instruction issuance with the MicroROS Agent of the host computer through the serial port.

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

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

[0063] Optionally, as Figure 5 shown, 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 after passing through an optical fiber, and then the transimpedance amplifier converts the photocurrent signal of the photodiode into a voltage signal. The analog-to-digital conversion chip converts the voltage signal into a digital signal and transmits it to the subsequent system for analysis.

[0064] Specifically, the electronic device module 400 further includes a separated multi-layer PCB board 420. The separated multi-layer PCB board 420 is mainly composed of five-layer PCB boards, and the boards are connected through board-to-board connectors; the five-layer PCB boards 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 signal transfer, and the power supply board is used for power supply.

[0065] Furthermore, the power supply board can convert the 12V DC voltage into 3.3V and 5V for all boards to use.

[0066] The five-layer boards are separated from each other and connected through board-to-board connectors to ensure function 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 distributed inside the soft arm in a distributed manner, thereby realizing the decoupling of each sub-unit. 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, data transmission between the boards can be achieved through the I 2 C protocol to ensure the efficient and stable operation of the system, while ensuring data real-time performance and system robustness.

[0068] In specific implementation, the board-to-board connector can be pins. That is, the physical connection and electrical connection between the boards are achieved through pins.

[0069] Specifically, the robotic arm body 300 includes an end cap 310, an arm body 320, an optical fiber connector 330, and a snap ring 340; an end cap 310 is arranged at each end of the arm body 320, and a helical artificial muscle array is arranged inside the arm body 320. Each helical artificial muscle is arranged along the axial direction of the arm body 320 and is embedded inside the arm body 320; a macro-bending optical fiber array is arranged on the radial outer side of the arm body 320, and a flexible optical fiber 220 passes through the center of the arm body 320; the end cap 310 arranged at the end of the arm body 320 is used to connect to external devices; a snap ring 340 is sleeved outside the end cap 310 arranged at the head end of the arm body 320. A number of through holes are provided on the snap ring 340, and an optical fiber connector 330 is installed in each through hole. The end of the macro-bending optical fiber 210 passes through the optical fiber connector 330 and is connected to an infrared emitter or a photodiode, and both the infrared emitter and the photodiode are electrically connected to the wiring board in the electronic device module 400; both ends of each helical artificial muscle are respectively connected to the two end caps 310; each macro-bending optical fiber 210 is connected to the arm body 320; the snap ring 340 is connected to the electronic device housing 410 in the electronic device module 400.

[0070] Preferably, the implementation manner of arranging the helical artificial muscle array inside the arm body 320 is as follows: The arm body 320 is made of silica gel material, and the arm body 320 has a columnar structure with a clover-shaped cross-section. The columnar structure has three independent lobe cavities arranged circumferentially and evenly. A helical artificial muscle is arranged along the axial direction in each independent lobe cavity, and the three helical artificial muscles form a helical artificial muscle array. The clover-shaped cross-section design of the arm body 320 enables the soft robotic arm to better couple the driving module 100 and the sensing module 200, and the robotic arm body 300 has good flexibility and operability to adapt to complex working environments.

[0071] Preferably, the implementation manner of connecting both ends of each helical artificial muscle to the two end caps 310 respectively is as follows: The driving module 100 further includes a connecting ring 120, and a connecting ring 120 is connected to each end of each helical artificial muscle; through slots are provided on the end cap 310, and the length of the through slot is smaller than the diameter of the connecting ring 120. The end of the helical artificial muscle passes through the through slot and is connected to the connecting ring 120.

[0072] Preferably, the implementation manner of connecting each macro-bending optical fiber 210 to the arm body 320 is as follows: A number of mounting grooves are provided on the surface of the arm body 320, which are arranged circumferentially and evenly spaced along the arm body 320. Each mounting groove is arranged along the axial direction of the arm body 320. The number of mounting grooves is the same as that of the macro-bending optical fibers 210 and they correspond 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 bonding or other means.

[0073] Preferably, the implementation method of passing the 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 passed through the central through hole. The soft optical fiber 220 can be fixed by means of interference fit or the like.

[0074] Optionally, the implementation method of connecting the end cap 310 to the arm body 320 is: The end cap 310 is embedded in the annular groove at the end of the arm body 320 and is in interference fit with the annular groove.

[0075] Furthermore, a number of cable installation holes are also provided on the arm body 320 for installing and connecting cables. For example, the cables for electrically connecting the ends of each spiral artificial muscle to the wiring board, the cables for electrically connecting the infrared emitting tube at the end of the soft optical fiber 220 to the wiring board, etc.

[0076] The second aspect of the present invention provides a manufacturing method for the above-mentioned body force and position sensing soft robotic arm

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

[0078] S1) Use a winding device to helically form a nylon polymer fiber and a nickel wire to obtain a spiral artificial muscle. Protect the spiral artificial muscle by pouring paraffin on the surface of each spiral artificial muscle to obtain a protected spiral artificial muscle;

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

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

[0081] S3) Install multiple macro-bending optical fibers 210 in the corresponding installation grooves on the surface of the arm body 320;

[0082] S4) Prepare a polyurethane waveguide. After coating the surface of the polyurethane waveguide with a silicone rubber material, obtain the soft optical fiber 220; Install the soft optical fiber 220 on the central hole of the arm body 320;

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

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

[0085] Embodiment

[0086] This embodiment provides a soft robotic arm with a columnar silicone structure having a clover-shaped cross-section for the robotic arm body 300, with three helical artificial muscles embedded inside. On one side of each helical artificial muscle, there is a cable installation hole for arranging the connection cables corresponding to the helical artificial muscle. In the center of the robotic arm body 300, there is a central hole for arranging a tactile sensor, and on one side of the central hole, there is a cable installation hole for arranging the connection cables 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 connects each sensor and the helical artificial muscle. The sensing board is responsible for processing sensor data and transmitting it to the main control board. The driving board receives the control signal from the main control board and transmits it to the driver part. The main control board generates a driving signal through the control algorithm in the upper computer according to the real-time data fed back by the sensors, and precisely adjusts the output force of the driver part to achieve efficient and precise motion control of the soft robotic arm. The main control circuit part ensures that the soft robotic arm can make adaptive adjustments according to the real-time sensing data to meet the requirements of various complex tasks.

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

[0089] S1) Use a winding device to helically form a nylon polymer fiber and a nickel wire to obtain a helical artificial muscle. Protect the helical artificial muscle by pouring paraffin on the surface of each helical artificial muscle to obtain a protected helical artificial muscle; during the protection process, a protective shell is formed after the paraffin solidifies on the surface of the helical artificial muscle, which can effectively prevent the silicone from curing in the helical gap of the helical artificial muscle and affecting the driving effect.

[0090] S2) Place multiple protected helical artificial muscles inside the mold. Mix the Ecoflex 00-50 two-component silicone and remove the air bubbles with a vacuum pump, and then inject it into the mold by the dispensing casting method to obtain an arm body 320 equipped with a driving module 100.

[0091] As Figure 5 shown, the casting mold is divided into upper and lower parts, and two end caps 310 with through holes in the center are respectively arranged at both ends. After closing and locking the mold, pass a steel rod through the end caps 310 and the central through hole of the mold, and then pour through the pouring hole.

[0092] The dispensing casting method is to slowly inject the mixed silicone into the mold until it overflows. Then place the mold in an oven at 50 °C until the silicone is completely cured. After curing, disassemble the mold, remove the steel rod and complete the cable welding, and then a flexible robotic arm body composed of a driving module 100, an arm body 320, and an end cap 310 can be obtained.

[0093] S3) Bend an optical fiber into a number of rings with equal perimeters to obtain a macro-bent optical fiber 210; install multiple macro-bent optical fibers 210 in corresponding installation grooves on the surface of the arm body 320 by means of bonding, and electrically connect the input end and output end of each macro-bent optical fiber 210 to an infrared emitting tube and a photodiode respectively. Both the infrared emitting tube and the photodiode are installed on the buckling snap ring 340;

[0094] In an embodiment of the present invention, an optical fiber CK30 with a diameter of 1 mm is bent into 7 rings with a perimeter of 60 mm to obtain a macro-bent optical fiber 210.

[0095] In an embodiment of the present invention, the models of the devices connected to the macro-bent optical fiber 210 are specifically: infrared emitting tube IR204-A and photodiode PD204-6B / L3.

[0096] S4) Use silicone to make a soft optical fiber mold with a hollow of 3 mm, fix a photodiode at one end of the soft optical fiber mold, mix polyurethane raw materials and perform vacuum treatment, and then slowly inject the vacuum-treated mixture into the soft optical fiber mold through a dispensing machine until the polyurethane overflows. Then insert an infrared emitting tube at the other end of the soft optical fiber mold and fix it; after the polyurethane cures, take out the polyurethane waveguide from the soft optical fiber mold, coat a low-refractive-index silicone rubber material on the surface of the polyurethane waveguide as the outer shell layer, and after the outer shell layer cures, obtain a soft optical fiber 220; install the soft optical fiber 220 through the following process:

[0097] Take the end of the soft optical fiber 220 where the infrared emitting tube is installed as the end, pass the soft optical fiber 220 through the central hole of the arm body 320, connect the infrared emitting tube at the end of the soft optical fiber 220 to one end of the cable, and after the other end of the cable passes through the cable installation hole arranged on one side of the central hole, connect it to the wiring board in the electronic device module 400. Electrically connect the photodiode at the first end of the soft optical fiber 22 to the wiring board in the electronic device module 400 through a cable;

[0098] In this embodiment, the polyurethane uses polyurethane VytaFlex 20 raw materials mixed in a ratio of 1:1.

[0099] In an embodiment of the present invention, the models of the devices connected to the soft optical fiber 220 are specifically: using an infrared emitting tube TSHA6203 and a photodiode SFH 213FA.

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

[0101] The foregoing has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and the descriptions in the above embodiments and the specification are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and all these changes and improvements fall within the scope of the present invention claimed.

Claims

1. A body force and position sensing soft robotic arm driven by a helical artificial muscle, characterized in that, Comprising: A robotic arm main body (300); A driving module (100), including a plurality of electrothermal driving type spiral artificial muscles arranged at intervals in the circumferential direction of the robotic arm main body (300), and each spiral artificial muscle is arranged along the axial direction of the robotic arm main body (300); A sensing module (200), including 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 spiral artificial muscle; An electronic device module (400), installed at the head end of the robotic arm main body (300), and electrically connected to the driving module (100) and the sensing module (200) respectively.

2. The body force-position sensing soft robotic arm according to claim 1, wherein: The spiral artificial muscle adopts an artificial muscle formed by helically shaping nylon polymer fibers and metal nickel wires. The driving module (100) realizes driving the soft robotic arm to perform two-degree-of-freedom bending motion by independently controlling the electrothermal driving contraction of each spiral artificial muscle.

3. The body force and position sensing soft robotic arm according to claim 1, wherein: The stretching sensor is mainly composed of a plurality of macro-bending optical fibers (210) arranged at intervals in the circumferential direction of the robotic arm main body (300), and each macro-bending optical fiber (210) is arranged along the axial direction of the robotic arm main body (300). The macro-bending optical fiber (210) is connected to the robotic arm main body (300); the number of macro-bending optical fibers (210) is the same as that of the spiral artificial muscles and is arranged symmetrically correspondingly. The output optical signal of each macro-bending optical fiber (210) serves as a pose signal. By real-time monitoring of the optical power loss of the pose signal, the pose state of the soft robotic arm can be monitored in real time; the tactile sensor adopts a soft optical fiber (220), and the soft optical fiber (220) is coaxially arranged through the center of the robotic arm main body (300). The output optical signal of the soft optical fiber (220) serves as a contact force signal. By real-time monitoring of the real-time light intensity of the contact force signal, the contact force at 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 both electrically connected to the electronic device module (400).

4. The body force-position sensing soft robotic arm according to claim 3, wherein: The number of the temperature sensors is the same as and corresponds to that of the spiral artificial muscles; the temperature sensor adopts a power monitoring chip, and the power monitoring chip is integrated in the electronic device module (400). The output signal of each power monitoring chip serves as the temperature signal of the corresponding spiral artificial muscle.

5. The body force-position sensing soft robotic arm according to claim 3, characterized in that: The electronic device module (400) includes: A sensing unit, 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 it 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; A driving unit, including a plurality of driving circuits, the number of the driving circuits is the same as and corresponds to that of the spiral artificial muscles. The driving circuit adopts a power amplification circuit, 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 single-chip microcomputer has its input ends electrically connected to the output ends of the sensing unit and the output ends of each temperature sensor respectively, its communication end communicatively connected to the host computer, and its output ends electrically connected to the control ends of each driving circuit respectively.

6. The body force and position sensing soft robotic arm according to claim 5, wherein: The electronic device module (400) further includes a separated multi-layer PCB board (420), which is mainly composed of five-layer PCB boards, and the boards are connected by board-to-board connectors; the five-layer PCB boards are a wiring board, a sensing board, a driving board, a main control board, and a power supply board respectively. 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 signal transfer, and the power supply board is used for power supply.

7. The body force-position sensing soft robotic arm according to claim 3, characterized in that: The robotic arm main body (300) includes an end cover (310), an arm body (320), an optical fiber connector (330), and a buckling snap ring (340); an end cover (310) is arranged at each end of the arm body (320). A spiral artificial muscle array is arranged inside the arm body (320). Each spiral artificial muscle is arranged along the axial direction of the arm body (320) and embedded inside the arm body (320); a macro-bending optical fiber array is arranged outside the arm body (320), and a soft optical fiber (220) passes through the center of the arm body (320); the end cover (310) arranged at the end of the arm body (320) is used to connect external devices; a buckling snap ring (340) is sleeved outside the end cover (310) arranged at the head end of the arm body (320). A plurality of through holes are formed in the buckling snap ring (340), and an optical fiber connector (330) is installed in each through hole. The end of the macro-bending 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); both ends of each spiral artificial muscle are respectively connected to the two end covers (310); each macro-bending optical fiber (210) is connected to the arm body (320); the buckling snap ring (340) is connected to the electronic device module (400).

8. The body force and position sensing soft robotic arm according to claim 7, wherein: The arm body (320) is made of silicone material. The arm body (320) has a columnar structure with a clover-shaped cross-section. The columnar structure has three independent lobe cavities arranged circumferentially and evenly. A spiral artificial muscle is arranged along the axial direction in each independent lobe cavity, and the three spiral artificial muscles form the spiral artificial muscle array.

9. The body force and position sensing soft robotic arm according to claim 7, wherein: The driving module (100) further includes a connecting ring (120). A connecting ring (120) is connected to each end of each spiral artificial muscle; a through groove is formed in the end cover (310), and the end of the spiral artificial muscle passes through the through groove and is connected to the connecting ring (120).

10. A manufacturing method for the body force and position sensing soft robotic arm according to any one of claims 1 to 9, characterized in that, It includes the following steps: S1) Use a winding device to helically form a nylon polymer fiber and a nickel wire to obtain a spiral artificial muscle, and pour paraffin on the surface of each spiral artificial muscle to obtain a spiral artificial muscle with protective treatment. S2) Place multiple protected spiral artificial muscles and two end caps (310) inside a mold (500), inject silicone, and after curing, take out the arm body (320) with the drive module (100) installed from the mold (500); S3) Install multiple macro-bending optical fibers (210) in the corresponding installation grooves on the surface of the arm body (320); S4) Prepare a polyurethane waveguide, and after coating the surface of the polyurethane waveguide with a silicone rubber material, obtain a soft optical fiber (220); install the soft optical fiber (220) on the central 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.

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