A micro magnetic vector control active bionic whisker sensor and sensing method

Abstract

The application discloses a micro magnetic vector control active bionic tentacle sensor and a sensing method, and relates to the technical field of micro robot tactile sensing, and comprises a base, a spherical permanent magnet rotatably arranged in the base, a bionic tentacle fixed on the spherical permanent magnet and swinging with the rotation of the spherical permanent magnet, a plurality of electromagnetic coils each fixed on the base and surrounding the outer circumferential side of the spherical permanent magnet, each electromagnetic coil being used for generating a magnetic field when being electrified, the magnetic field vectors of the electromagnetic coils being superposed to synthesize a target magnetic field vector with an arbitrary spatial direction, and the target magnetic field vector being used for driving the spherical permanent magnet to deflect to a target direction; a magnetic field measuring unit fixed on the base; a control unit electrically connected with the electromagnetic coils and the magnetic field measuring unit; and active bionic tactile sensing can be realized in a small volume, and the accurate tracking of the tentacle posture is ensured.

Description

Technical Field

[0001] This invention relates to the field of tactile sensing technology for micro-robots, and in particular to a micro-magnetic vector controlled active biomimetic whisker sensor and sensing method. Background Technology

[0002] Bionic whisker sensors are biomimetic devices that mimic the tactile perception mechanism of mammalian whiskers. They acquire information such as the size, shape, orientation, and texture of external objects through whisker waving and contact deformation. They are core components for robots to achieve environmental perception in dim, complex, and confined environments, and are widely used in fields such as miniature detection robots and industrial endoscopic inspection. With the development of micro-miniature intelligent equipment, higher demands are placed on the miniaturization, active control capabilities, and sensing accuracy of whisker sensors.

[0003] Existing active bionic tentacle sensors, in some existing technologies, employ an electromagnet array to drive a pendulum-type permanent magnet, causing the tentacle to swing. This approach controls the on / off state of multiple discrete electromagnets to drive the pendulum's deflection, achieving active tentacle swinging, and determines the contact state by detecting deformation signals at the tentacle root. However, this approach requires multiple electromagnets to achieve active tentacle swinging, resulting in redundant drive structures and complex mechanical supports, leading to a large overall sensor size, typically exceeding 30mm in diameter. This makes it unsuitable for confined spaces such as micro-robots and minimally invasive instruments with dimensions under 10cm. Furthermore, the electromagnet array can only achieve point-to-point control, with cumbersome adjustment logic, unable to achieve three-dimensional omnidirectional continuous vector control, resulting in low tentacle movement accuracy and lag, only achieving fixed-angle swinging. Additionally, this approach incorporates a deformation detection module at the tentacle root, measuring the resistance or deformation signal at the root when the tentacle bends to determine if it has contacted an obstacle. This method only detects "contact," failing to accurately obtain the three-dimensional spatial position of the contact point, and is insensitive to weak contact at the tentacle tip.

[0004] Furthermore, existing tactile sensors mostly use rigid rods with uniform cross-sections, lacking biomimetic mechanical design and failing to replicate the core characteristics of biological tentacles, such as tapered gradients and stiffness gradients. The uniform cross-section straight rods exhibit a uniform linear stiffness change, making it impossible to accurately encode tactile signals, difficult to identify minute obstacles and fine textures, and thus limiting their sensing capabilities. Summary of the Invention

[0005] The purpose of this invention is to provide a miniature magnetic vector controlled active bionic tactile sensor and sensing method to solve the problems existing in the prior art, realize active bionic tactile sensing in a small volume, and ensure accurate tracking of tactile posture.

[0006] To achieve the above objectives, the present invention provides the following solution: The present invention provides a miniature magnetic vector controlled active biomimetic tentacle sensor, comprising: Base; A spherical permanent magnet is rotatably mounted inside the base; Bionic tentacles are fixed to the spherical permanent magnet and swing as the spherical permanent magnet rotates; Multiple electromagnetic coils are fixed on the base and surround the outer periphery of the spherical permanent magnet. Each electromagnetic coil generates a magnetic field when energized. The magnetic field vectors of each electromagnetic coil are superimposed to form a target magnetic field vector pointing in any space, which is used to drive the spherical permanent magnet to deflect toward the target. A magnetic field measurement unit, which is fixed on the base, is used to measure the measured magnetic moment vector of the spherical permanent magnet in real time. The control unit, which is electrically connected to the electromagnetic coil and the magnetic field measuring unit, is used to adjust the current of each electromagnetic coil according to the deviation between the measured magnetic moment vector and the target magnetic moment vector, thereby forming a closed-loop control.

[0007] Optionally, each of the electromagnetic coils is arranged with an oblique upward orientation and is uniformly wrapped around the outer periphery of the spherical permanent magnet, and the intersection of the axes of each electromagnetic coil coincides with the center of the spherical permanent magnet.

[0008] Optionally, the base adopts a three-layer three-dimensional stacked structure, and includes a control layer, a sensing layer and a driving layer distributed from bottom to top; The control layer is provided with a PCB circuit board, and the control unit is disposed on the PCB circuit board; The sensing layer is equipped with the magnetic field measurement unit, which is located directly below the spherical permanent magnet and connected to the control layer. The driving layer is provided with the spherical permanent magnet and each of the electromagnetic coils.

[0009] Optionally, the base is a fully modular integrated packaging structure, and it has an internal electrical connection channel, which is used for signal transmission between the electromagnetic coil and the control unit.

[0010] Optionally, the control unit includes an MCU controller, and the magnetic field measurement unit includes a triaxial magnetic field measurement chip; the PCB circuit board integrates the MCU controller, the communication chip, the triaxial magnetic field measurement chip, and multiple coil drive chips; each coil drive chip is electrically connected to each electromagnetic coil in a one-to-one correspondence, the triaxial magnetic field measurement chip is electrically connected to the MCU controller, and the MCU controller communicates with a host computer through the communication chip; The MCU controller measures the three-dimensional magnetic moment of the spherical permanent magnet in real time through the triaxial magnetic field measurement chip to calculate the measured magnetic moment vector; The MCU controller interacts with the host computer through the communication chip, sending the measured magnetic moment vector and receiving control commands; The MCU controller controls each of the coil drive chips to drive the corresponding electromagnetic coil according to the control instructions of the host computer, thereby controlling the spherical permanent magnet to drive the bionic tendrils to swing.

[0011] Optionally, the MCU controller controls the current output of each coil driver chip to the corresponding electromagnetic coil via a PWM signal; the control unit uses time-division multiplexing to divide the control cycle into a control period and a measurement period. During the control period, the electromagnetic coil is energized to drive the spherical permanent magnet, and during the measurement period, the electromagnetic coil is de-energized and the measured magnetic moment vector is measured by the triaxial magnetic field measuring chip. A demagnetization pause time is provided between the control period and the measurement period.

[0012] Optionally, the bionic tentacle has a hollow structure, with its base diameter being larger than its tip diameter, and the internal hollow cavity of the bionic tentacle gradually closes from the base to the tip, so as to provide the bionic tentacle with a gradual stiffness gradient along its axial direction.

[0013] Optionally, the base is provided with an arc-shaped base, which is fixed on the spherical permanent magnet.

[0014] A perception method is also provided, comprising the following steps: The spherical permanent magnet is driven to make the bionic tendrils swing, and the measured magnetic moment vector measured by the magnetic field measurement unit is acquired in real time; When the bionic tentacles are not in contact with an obstacle, the measured magnetic moment vector tracks the target magnetic moment vector; When the bionic tendrils come into contact with an obstacle, the spherical permanent magnet is subjected to an external torque, and a deviation occurs between the measured magnetic moment vector and the target magnetic moment vector; Based on the spatial phase difference between the measured magnetic moment vector and the target magnetic moment vector, the azimuth angle of the obstacle contact point relative to the bionic tentacle is determined; Based on the response delay of the deviation between the measured magnetic moment vector and the target magnetic moment vector, and combined with the stiffness gradient characteristics of the bionic tentacle, the axial distance from the obstacle contact point to the root of the bionic tentacle is calculated.

[0015] Optionally, in the step of determining the azimuth angle and in the step of calculating the axial distance, the control unit performs the following operations: S1. Receive the active detection path instruction generated by the host computer, calculate and output the corresponding target magnetic moment vector sequence to provide a driving reference for the bionic tentacles; S2. Read the measured magnetic moment vector fed back by the magnetic field measurement unit in real time, compare it with the target magnetic moment vector at the same time, and adjust the current of each electromagnetic coil in real time through a closed-loop control algorithm to drive the spherical permanent magnet to drive the bionic tendrils to track the preset detection path. S3. When the bionic tentacles come into contact with an obstacle during the swinging process, the external contact force is transmitted to the spherical permanent magnet through the bionic tentacles and forms a disturbance torque, causing the attitude of the spherical permanent magnet to deviate, and the measured magnetic moment vector deviates from the target magnetic moment vector. S4. Analyze the spatial phase difference between the measured magnetic moment vector and the target magnetic moment vector to determine the azimuth angle corresponding to the contact point of the obstacle; at the same time, detect the response delay when the measured magnetic moment vector deviates significantly from the target magnetic moment vector, and calculate the axial distance from the contact point to the root of the bionic tentacle by combining the stiffness gradient model of the bionic tentacle. Finally, fuse the azimuth angle and the axial distance to calculate the three-dimensional position of the contact point.

[0016] The present invention achieves the following technical effects compared to the prior art: This invention discloses a miniature magnetic vector controlled active bionic tentacle sensor. A spherical permanent magnet serves as the driving element, and the entire sensor primarily drives the rotation of the spherical permanent magnet, while simultaneously integrating the bionic tentacle with it. Four electromagnetic coils synthesize a magnetic field vector pointing in arbitrary space, driving the spherical permanent magnet to move the bionic tentacle in three-dimensional omnidirectional oscillations, enabling active bionic tactile sensing within a small volume. Simultaneously, a magnetic field measurement unit provides real-time feedback of the actual magnetic moment vector of the spherical permanent magnet, forming a closed-loop control with the control unit to ensure precise tracking of the tentacle's posture. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of a miniature magnetic vector controlled active biomimetic tentacle sensor, as disclosed in an example of the present invention. Among them, 1-bionic tentacles, 2-spherical permanent magnet, 3-electromagnetic coil, 4-coil fixing base, 5-PCB circuit board, and 6-magnetic ball fixing base. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] The purpose of this invention is to provide a miniature magnetic vector controlled active bionic tactile sensor and sensing method to solve the problems existing in the prior art, realize active bionic tactile sensing in a small volume, and ensure accurate tracking of tactile posture.

[0021] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] like Figure 1 As shown, the present invention provides a miniature magnetic vector controlled active bionic tentacle sensor, including a base, a spherical permanent magnet 2, a bionic tentacle 1, multiple electromagnetic coils 3, a magnetic field measurement unit and a control unit.

[0023] A spherical permanent magnet 2 is rotatably mounted within the base, and a bionic tentacle 1 is fixed to the spherical permanent magnet 2 and swings as the spherical permanent magnet 2 rotates. Preferably, the bionic tentacle 1 is directly fixed to the spherical permanent magnet 2, which is installed in a magnetic ball holder 6 within the base. The magnetic ball holder 6 is coated with lubricating oil to ensure low-friction rotation of the spherical permanent magnet 2. In some specific examples, the spherical permanent magnet 2 has a diameter of 3mm and a small moment of inertia. Combined with high-frequency closed-loop control, the tentacle command response time can reach the millisecond level, enabling high-speed active sweeping detection and meeting the real-time sensing needs of high-speed mobile micro-robots.

[0024] Multiple electromagnetic coils 3 are fixed to the base and surround the outer periphery of the spherical permanent magnet 2. Each electromagnetic coil 3 generates a magnetic field when energized. The magnetic field vectors of each electromagnetic coil 3 are superimposed to form a target magnetic field vector pointing in any spatial direction, which drives the spherical permanent magnet 2 to deflect towards the target. The electromagnetic coil 3 contains a magnetic core and is directly fixed to the coil fixing base 4. While generating a horizontal magnetic field component, the electromagnetic coil 3 can simultaneously generate a vertical magnetic field component. By independently adjusting the magnitude and direction of the current in each electromagnetic coil 3, the magnetic fields can be vector-superimposed to form a target magnetic field vector pointing in any spatial direction. Under the action of the combined magnetic field, the spherical permanent magnet 2 is driven by a magnetic torque and can deflect towards the target, thus realizing the omnidirectional active driving of the bionic tentacle 1 in three-dimensional space. The spherical permanent magnet 2 is constrained within the magnetic ball fixing base 6 and can only rotate freely without translation.

[0025] The magnetic field measurement unit is fixed on the base and is used to measure the measured magnetic moment vector of the spherical permanent magnet 2 in real time. Preferably, the magnetic field measurement unit adopts a triaxial magnetic field sensor, and preferably a miniature triaxial magnetic field sensor, which is arranged directly below the spherical permanent magnet 2.

[0026] The control unit is electrically connected to the electromagnetic coil 3 and the magnetic field measurement unit. It adjusts the current of each electromagnetic coil 3 based on the deviation between the measured magnetic moment vector and the target magnetic moment vector, forming a closed-loop control. Preferably, the control unit includes, but is not limited to, an MCU controller. To eliminate attitude deviations caused by the inertia, structural friction, and magnetic field disturbances of the spherical permanent magnet 2, the control unit acquires the current magnetic moment direction of the spherical permanent magnet 2 in real time through the magnetic field measurement unit and inputs it to the MCU controller. The MCU controller compares the target magnetic moment vector with the measured magnetic moment vector in real time and dynamically adjusts the output current of the four coils through a closed-loop control algorithm, continuously correcting the spatial synthetic magnetic field. This enables the spherical permanent magnet 2 to quickly and accurately track the target command, ultimately forming a stable and reliable three-dimensional omnidirectional vector closed-loop drive.

[0027] This invention discloses a miniature magnetic vector controlled active bionic tentacle sensor 1, using a spherical permanent magnet 2 as the driving element. The entire sensor primarily drives the rotation of the spherical permanent magnet 2, while simultaneously integrating the bionic tentacle 1 with the spherical permanent magnet 2. Four electromagnetic coils 3 synthesize a magnetic field vector pointing in arbitrary space, driving the spherical permanent magnet 2 to cause the bionic tentacle 1 to oscillate in three dimensions, achieving active bionic tactile sensing within a small volume. Simultaneously, a magnetic field measurement unit provides real-time feedback of the actual magnetic moment vector of the spherical permanent magnet 2, forming a closed-loop control with the control unit to ensure accurate tracking of the tentacle's posture.

[0028] In one embodiment, each electromagnetic coil 3 is arranged with an upward oblique orientation and uniformly surrounds the outer periphery of the spherical permanent magnet 2, with the intersection of the axes of each electromagnetic coil 3 coinciding with the center of the spherical permanent magnet 2. By arranging the electromagnetic coils 3 with an upward oblique orientation, the electromagnetic coils 3 can simultaneously generate a vertical magnetic field component while generating a horizontal magnetic field component. This allows for the vector superposition of the various magnetic fields to synthesize a target magnetic field vector pointing in any spatial direction. The coincidence of the intersection of the axes of each electromagnetic coil 3 with the center of the spherical permanent magnet 2 ensures the uniformity and pointing accuracy of the synthesized magnetic field at the spherical position of the spherical permanent magnet 2, aligning the direction of the magnetic torque on the spherical permanent magnet 2 with the target direction, thus improving driving accuracy.

[0029] Based on this implementation, in some specific examples, the number of electromagnetic coils 3 is four, which can be arranged circumferentially and defined as four driving units: X+, X-, Y+, and Y-. This allows the four electromagnetic coils 3 to be installed in four different locations, with the intersection of their axes coinciding with the center of the spherical permanent magnet 2. Furthermore, the electromagnetic coils 3 are preferably oriented at a 45-degree angle upwards, which facilitates the simultaneous generation of a vertical magnetic field component while simultaneously generating a horizontal magnetic field component.

[0030] In one embodiment, the base adopts a three-layer stacked structure, including a control layer, a sensing layer, and a driving layer distributed sequentially from bottom to top. In some specific examples, the overall dimensions of the base are no more than 20mm in diameter and no more than 10mm in height, forming a hemispherical base. The control layer has a PCB circuit board 5, and the control unit is mounted on the PCB circuit board 5. Preferably, the PCB circuit board 5 uses SMT technology to mount the components, resulting in a compact layout and no redundant traces. The sensing layer has a magnetic field measurement unit, which is located directly below the spherical permanent magnet 2 and connected to the control layer, for example, by direct soldering, achieving stable signal transmission without additional leads. The driving layer has the spherical permanent magnet 2 and various electromagnetic coils 3. The driving layer has built-in magnetic ball fixing seats 6 and coil fixing seats 4 to respectively mount the spherical permanent magnet 2 and electromagnetic coils 3. The coils are evenly arranged in an upward-sloping manner, forming a symmetrical driving structure around the spherical permanent magnet 2.

[0031] The entire base integrates driving, sensing, and control functions into a very small space through a vertically layered stacked layout, no external lead connections, miniaturized component selection, and integrated structural molding. This structural, technological, and connection-based approach ensures high-density integration. It is understandable that existing technologies have long been limited by the inherent design concepts of traditional tactile sensors, generally employing the design inertia of directly driving tactile structures, resulting in complex control and large size. This invention uses a spherical permanent magnet 2 as the driving element. The entire sensor primarily drives the rotation of the spherical permanent magnet 2, while simultaneously incorporating a biomimetic tactile sensory element 1. Finally, the two are combined to achieve active biomimetic tactile sensing within a small volume.

[0032] Based on the above implementation method, the overall size of the sensor, excluding the tentacles, is controlled within the range of diameter not exceeding 20mm and height not exceeding 10mm. It can be embedded in platforms such as micro-drones, minimally invasive interventional instruments, and endoscopic detection probes, breaking through the bottleneck of existing technologies being unable to adapt to narrow spaces, and is suitable for scenarios such as micro-robot pipeline inspection.

[0033] In one embodiment, the base is a fully modular integrated package structure, and it has an internal electrical connection channel for signal transmission between the electromagnetic coil 3 and the control unit. Specifically, there are no external wires between the layers inside the base; signal transmission between the electromagnetic coil 3 and the control unit is achieved through the internal electrical connection channel of the base. The fully modular integrated package reduces external wires and interfaces, significantly improving anti-interference capabilities and mechanical reliability.

[0034] In one embodiment, the control unit includes an MCU controller, and the magnetic field measurement unit includes a triaxial magnetic field measurement chip. The PCB circuit board 5 integrates the MCU controller, communication chip, triaxial magnetic field measurement chip, and multiple coil drive chips. Each coil drive chip is electrically connected to each electromagnetic coil 3 in a one-to-one correspondence. The triaxial magnetic field measurement chip is electrically connected to the MCU controller, and the MCU controller communicates with a host computer via the communication chip. The MCU controller is used to measure the three-dimensional magnetic moment of the spherical permanent magnet 2 in real time using the triaxial magnetic field measurement chip to calculate the measured magnetic moment vector. The MCU controller interacts with the host computer via the communication chip, sending the measured magnetic moment vector and receiving control commands. Based on the control commands from the host computer, the MCU controller controls each coil drive chip to drive its corresponding electromagnetic coil 3, thereby controlling the spherical permanent magnet 2 to move the bionic tendril 1.

[0035] The PCB circuit board 5 integrates an MCU controller, a communication chip, a triaxial magnetic field measurement chip, and multiple coil driver chips, achieving a high degree of integration of control, sensing, and communication functions. The MCU controller, as the core of the control unit, is responsible for magnetic field data acquisition and analysis, data transmission, and control of the electromagnetic coil 3. All components are soldered using SMT (Surface Mount Technology) technology, reducing the size and thickness of the PCB circuit board 5 and meeting the requirements of miniaturization design. As a preferred example, the communication chip is an I2C / SPI communication chip used for communication with the host computer. To reduce the size of the PCB board 5, all components are soldered onto the board using SMT (Surface Mount Technology).

[0036] As a preferred example, the electromagnetic coil 3 is a miniature coil and the MCU controller is a low-power type, so that the peak power consumption of the system is controlled at the milliwatt level, making it suitable for battery-powered portable micro-sized devices.

[0037] In one embodiment, the MCU controller controls the current output from each coil drive chip to the corresponding electromagnetic coil 3 via a PWM signal, thereby controlling the output magnetic field of the coil. To control the rotation of the spherical permanent magnet 2, the magnetic fields of all electromagnetic coils 3 are calculated and combined into a single coupled magnetic vector by the MCU controller. Since the magnetic field generated when the coil is energized interferes with the measurement results of the triaxial magnetic field measurement chip, the MCU controller uses time-division multiplexing to divide the control cycle into a control period and a measurement period. During the control period, the electromagnetic coil 3 is energized to drive the spherical permanent magnet 2; during the measurement period, the electromagnetic coil 3 is de-energized, and the measured magnetic moment vector is measured by the triaxial magnetic field measurement chip. A demagnetization pause time is provided between the control and measurement periods, mainly for demagnetizing the magnetic field after it is de-energized. This separates the magnetic field measurement and control, ensuring the accuracy of the magnetic moment measurement of the spherical permanent magnet 2. The time-division multiplexing method effectively solves the problem of mutual interference between coil drive and magnetic field measurement. The control period is used for driving, and the measurement period is used for sensing. The two are separated in time, which ensures that the triaxial magnetic field measurement chip is not disturbed by the coil magnetic field during measurement, thereby obtaining accurate magnetic moment data of the spherical permanent magnet 2.

[0038] In one embodiment, the biomimetic tentacle 1 has a hollow structure, with its base diameter larger than its tip diameter. The internal hollow cavity of the tentacle 1 gradually closes from the base to the tip, providing a gradual stiffness gradient along its axial direction. Based on biomimetic principles, the tentacle is designed as a hollow structure with a large diameter at the bottom and a small diameter at the top, thereby creating a stiffness gradient along the axis and achieving variable stiffness. As a preferred example, the base of the biomimetic tentacle 1 is provided with an arc-shaped base, which is directly fixed to the spherical permanent magnet 2.

[0039] The conical hollow design of the biomimetic tentacle 1 gives it a gradually changing stiffness gradient along its axis. The large diameter and thick wall at the base ensure high stiffness, guaranteeing efficient transmission of the driving torque from the spherical permanent magnet 2 and maintaining the tentacle's motion stability during active oscillation. The smooth, gradual change in stiffness in the middle section ensures that the mechanical signals generated by contact are transmitted to the root without distortion or loss. The small diameter and thin wall at the tip result in low stiffness, making the tentacle highly sensitive to weak contact forces and enabling precise identification of textures and minute obstacles. The arc-shaped base facilitates the fixed connection between the tentacle and the spherical permanent magnet 2, ensuring reliable force transmission.

[0040] In one embodiment, the biomimetic tentacle 1 is fabricated using MEMS micro-nano processing. The tentacle has an elliptical cross-section and an overall tapered, gradually changing structure. Through a hollow interior that closes towards the tip, a nonlinear stiffness gradient is achieved from the base to the tip, conforming to the mechanical properties of biological tentacles. The tentacle's combination of external tapering and internal hollow cavities from base to tip creates a nonlinear change in the moment of inertia along its length. The base has a thicker wall and a larger effective load-bearing cross-section, resulting in higher stiffness. The closer to the tip, the thinner the wall and the greater the proportion of hollow sections, leading to a faster decrease in stiffness. This ultimately results in a nonlinear stiffness distribution: high stiffness at the root, a smooth transition in the middle, and extreme softness at the tip, unlike the uniform linear stiffness variation of a straight rod with a uniform cross-section. It is understood that biological tentacles such as mouse whiskers and seal whiskers possess this type of stiffness distribution characteristic.

[0041] Furthermore, a sensing method is also provided, comprising the following steps: A spherical permanent magnet 2 drives the bionic tentacle 1 to swing, and the measured magnetic moment vector obtained by the magnetic field measurement unit is acquired in real time. When the bionic tentacle 1 is not in contact with an obstacle, the measured magnetic moment vector tracks the target magnetic moment vector, and the deviation between the two is kept within a very small range. When the bionic tentacle 1 comes into contact with an obstacle, the spherical permanent magnet 2 is subjected to an external torque, and a deviation occurs between the measured magnetic moment vector and the target magnetic moment vector. This deviation is not eliminated by closed-loop compensation, but is instead stably extracted by the closed-loop system as the core signal for tactile perception. Based on the spatial phase difference between the measured magnetic moment vector and the target magnetic moment vector, the azimuth angle of the obstacle contact point relative to the bionic tentacle 1 is determined. Based on the response delay of the deviation between the measured magnetic moment vector and the target magnetic moment vector, combined with the stiffness gradient characteristics of the bionic tentacle 1, the axial distance from the obstacle contact point to the root of the bionic tentacle 1 is calculated.

[0042] This method uses a magnetic moment vector tracking closed loop instead of a position rigid servo closed loop. The purpose of the closed loop is to respond quickly to magnetic moment commands and maintain dynamic tracking, rather than to completely cancel out external contact disturbances.

[0043] This method reuses the drive system itself as a sensing system, eliminating the need for an additional deformation detection module. When the tentacle is not in contact with an obstacle, the measured magnetic moment vector can stably track the target magnetic moment vector. When the tentacle contacts an obstacle and generates an external torque, the magnetic ball's attitude is constrained and cannot fully track the command, resulting in an observable phase difference and response delay between the measured and target magnetic moment vectors. This deviation serves as the core signal for tactile perception. This drive-as-a-sensor approach achieves high-precision drive and high-precision perception simultaneously within a very small volume. By analyzing the spatial phase difference to determine the azimuth angle, and by analyzing the response delay and combining it with the stiffness gradient to calculate the axial distance, the three-dimensional precise positioning of the contact point is ultimately achieved. The sensor can be programmed to perform complex contour scanning and real-time deviation analysis, and can construct a local three-dimensional tactile map, realizing a leap from passive contact detection to active environmental cognition and improving the autonomous perception capability of micro-robots.

[0044] In one embodiment, the control unit performs the following operations in the steps of determining the azimuth angle and calculating the axial distance: S1. Receive the active detection path command generated by the host computer, calculate and output the corresponding target magnetic moment vector sequence, providing a driving reference for the bionic tentacle 1. The purpose of this step is to clarify the active detection trajectory of the tentacle and establish a unified target reference for subsequent closed-loop control and deviation detection.

[0045] S2. The measured magnetic moment vector fed back by the magnetic field measurement unit is read in real time and compared with the target magnetic moment vector at the same moment. The current of each electromagnetic coil 3 is adjusted in real time through a closed-loop control algorithm to drive the spherical permanent magnet 2 to move the bionic tentacles 1 to track the preset detection path. The purpose of this step is to achieve high-precision and high-stability active oscillation of the tentacles, ensuring that the tentacles complete the sweeping action according to the planned path, and at the same time establish a stable and reliable reference state for subsequent contact disturbance detection.

[0046] S3. When the bionic tentacle 1 comes into contact with an obstacle during its swing, the external contact force is transmitted to the spherical permanent magnet 2 through the bionic tentacle 1, forming a disturbance torque. This causes the attitude of the spherical permanent magnet 2 to deviate, and the measured magnetic moment vector deviates from the target magnetic moment vector. The purpose of this step is to capture the magnetic ball attitude disturbance caused by the obstacle contact, convert the physical contact signal into a detectable magnetic moment vector deviation signal, and provide effective data for subsequent contact position calculation.

[0047] S4. Analyze the spatial phase difference between the measured magnetic moment vector and the target magnetic moment vector to determine the azimuth angle corresponding to the obstacle contact point; simultaneously detect the response delay when the measured magnetic moment vector deviates significantly from the target magnetic moment vector, and calculate the axial distance from the contact point to the root of bionic tentacle 1 using the stiffness gradient model of bionic tentacle 1. Finally, fuse the azimuth angle and axial distance to calculate the three-dimensional position of the contact point. The purpose of this step is to achieve accurate calculation of the contact position, realize the synchronous measurement of obstacle orientation and distance, and complete the entire active bionic tactile perception process.

[0048] The four steps described above constitute a complete active bionic tactile perception process. Steps one and two establish the driving benchmark and stable tracking state; step three captures the occurrence of contact disturbances; and step four completes the accurate calculation of the contact position. The entire process achieves closed-loop perception from active detection and contact detection to position calculation, enabling the sensor to have the ability to actively recognize the environment from passive contact detection. Abandoning the traditional passive tactile switch mode, the sensor can be programmed to perform complex contour scanning and construct a local three-dimensional tactile map through real-time deviation analysis, thereby improving the autonomous perception capability of micro-robots.

[0049] Any adaptive changes made according to actual needs are within the scope of protection of this invention.

[0050] It should be noted that, for those skilled in the art, it is obvious that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0051] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A miniature magnetic vector controlled active biomimetic tentacle sensor, characterized in that, include: Base; A spherical permanent magnet is rotatably mounted inside the base; Bionic tentacles are fixed to the spherical permanent magnet and swing as the spherical permanent magnet rotates; Multiple electromagnetic coils are fixed on the base and surround the outer periphery of the spherical permanent magnet. Each electromagnetic coil generates a magnetic field when energized. The magnetic field vectors of each electromagnetic coil are superimposed to form a target magnetic field vector pointing in any space, which is used to drive the spherical permanent magnet to deflect toward the target. A magnetic field measurement unit, which is fixed on the base, is used to measure the measured magnetic moment vector of the spherical permanent magnet in real time. The control unit, which is electrically connected to the electromagnetic coil and the magnetic field measuring unit, is used to adjust the current of each electromagnetic coil according to the deviation between the measured magnetic moment vector and the target magnetic moment vector, thereby forming a closed-loop control.

2. The miniature magnetic vector controlled active bionic tentacle sensor according to claim 1, characterized in that, Each of the electromagnetic coils is arranged with an oblique upward orientation and is uniformly wrapped around the outer periphery of the spherical permanent magnet, and the intersection of the axes of each electromagnetic coil coincides with the center of the spherical permanent magnet.

3. The miniature magnetic vector controlled active bionic tentacle sensor according to claim 1, characterized in that, The base adopts a three-layer three-dimensional stacked structure, and includes a control layer, a sensing layer and a driving layer distributed from bottom to top; The control layer is provided with a PCB circuit board, and the control unit is disposed on the PCB circuit board; The sensing layer is equipped with the magnetic field measurement unit, which is located directly below the spherical permanent magnet and connected to the control layer. The driving layer is provided with the spherical permanent magnet and each of the electromagnetic coils.

4. The miniature magnetic vector controlled active bionic tentacle sensor according to claim 3, characterized in that, The base is a fully modular integrated packaging structure, and it has an internal electrical connection channel. The electromagnetic connection channel is used for signal transmission between the electromagnetic coil and the control unit.

5. The miniature magnetic vector controlled active bionic tentacle sensor according to claim 3, characterized in that, The control unit includes an MCU controller, and the magnetic field measurement unit includes a triaxial magnetic field measurement chip. The PCB circuit board integrates the MCU controller, the communication chip, the triaxial magnetic field measurement chip, and multiple coil drive chips. Each coil drive chip is electrically connected to each electromagnetic coil in a one-to-one correspondence. The triaxial magnetic field measurement chip is electrically connected to the MCU controller, and the MCU controller communicates with a host computer through the communication chip. The MCU controller measures the three-dimensional magnetic moment of the spherical permanent magnet in real time through the triaxial magnetic field measurement chip to calculate the measured magnetic moment vector; The MCU controller interacts with the host computer through the communication chip, sending the measured magnetic moment vector and receiving control commands; The MCU controller controls each of the coil drive chips to drive the corresponding electromagnetic coil according to the control instructions of the host computer, thereby controlling the spherical permanent magnet to drive the bionic tendrils to swing.

6. The miniature magnetic vector controlled active bionic tentacle sensor according to claim 5, characterized in that, The MCU controller controls the current output of each coil driver chip to the corresponding electromagnetic coil through a PWM signal; the control unit adopts a time-division multiplexing method to divide the control cycle into a control period and a measurement period. During the control period, the electromagnetic coil is energized to drive the spherical permanent magnet, and during the measurement period, the electromagnetic coil is de-energized and the measured magnetic moment vector is measured by the triaxial magnetic field measuring chip. A demagnetization pause time is provided between the control period and the measurement period.

7. The miniature magnetic vector controlled active bionic tentacle sensor according to claim 1, characterized in that, The bionic tentacles are hollow structures with a base diameter larger than a tip diameter, and the internal hollow cavities of the bionic tentacles gradually close from the base to the tip, providing the bionic tentacles with a gradual stiffness gradient along their axial direction.

8. The miniature magnetic vector controlled active bionic tentacle sensor according to claim 8, characterized in that, The base is provided with an arc-shaped base, which is fixed on the spherical permanent magnet.

9. A sensing method using an active biomimetic tentacle sensor with micro-magnetic vector control as described in any one of claims 1 to 8, characterized in that, Includes the following steps: The spherical permanent magnet is driven to make the bionic tendrils swing, and the measured magnetic moment vector measured by the magnetic field measurement unit is acquired in real time; When the bionic tentacles are not in contact with an obstacle, the measured magnetic moment vector tracks the target magnetic moment vector; When the bionic tendrils come into contact with an obstacle, the spherical permanent magnet is subjected to an external torque, and a deviation occurs between the measured magnetic moment vector and the target magnetic moment vector; Based on the spatial phase difference between the measured magnetic moment vector and the target magnetic moment vector, the azimuth angle of the obstacle contact point relative to the bionic tentacle is determined; Based on the response delay of the deviation between the measured magnetic moment vector and the target magnetic moment vector, and combined with the stiffness gradient characteristics of the bionic tentacle, the axial distance from the obstacle contact point to the root of the bionic tentacle is calculated.

10. The sensing method according to claim 9, characterized in that, In the steps of determining the azimuth angle and calculating the axial distance, the control unit performs the following operations: S1. Receive the active detection path instruction generated by the host computer, calculate and output the corresponding target magnetic moment vector sequence to provide a driving reference for the bionic tentacles; S2. Read the measured magnetic moment vector fed back by the magnetic field measurement unit in real time, compare it with the target magnetic moment vector at the same time, and adjust the current of each electromagnetic coil in real time through a closed-loop control algorithm to drive the spherical permanent magnet to drive the bionic tendrils to track the preset detection path. S3. When the bionic tentacles come into contact with an obstacle during the swinging process, the external contact force is transmitted to the spherical permanent magnet through the bionic tentacles and forms a disturbance torque, causing the attitude of the spherical permanent magnet to deviate, and the measured magnetic moment vector deviates from the target magnetic moment vector. S4. Analyze the spatial phase difference between the measured magnetic moment vector and the target magnetic moment vector to determine the azimuth angle corresponding to the contact point of the obstacle; at the same time, detect the response delay when the measured magnetic moment vector deviates significantly from the target magnetic moment vector, and calculate the axial distance from the contact point to the root of the bionic tentacle by combining the stiffness gradient model of the bionic tentacle. Finally, fuse the azimuth angle and the axial distance to calculate the three-dimensional position of the contact point.

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