Search

CN-122008165-A - Tendon-like and driving-sensing integrated rope driving device based on composite knitting structure

CN122008165ACN 122008165 ACN122008165 ACN 122008165ACN-122008165-A

Abstract

The invention discloses a tendon-like and driving-sensing integrated rope driving device based on a composite knitting structure, and belongs to the technical field of high and new technology drivers. The tendon-like body takes the fiber Bragg grating as a sensing layer and comprises an optical fiber and an external braiding layer, wherein a grating section with a set period is carved on the fiber core of the optical fiber, the surface of the optical fiber is covered with a polymer coating layer, the braiding layer and the optical fiber are subjected to multi-strand cross braiding according to a preset braiding angle, and the axial tension can be linearly transferred to the fiber Bragg grating in proportion by controlling the braiding angle. The tendon-like component which is simple in structure and can stably work for a long time is designed, so that the rope driving device with integrated driving and sensing functions is realized, and the control performance of the rope driving exoskeleton or the flexible driving system is improved.

Inventors

  • DENG HAO
  • FANG PENG
  • LI GUANGLIN

Assignees

  • 中国科学院深圳先进技术研究院

Dates

Publication Date
20260512
Application Date
20260205

Claims (10)

  1. 1. The tendon-like body based on the composite braiding structure is characterized by taking an optical fiber Bragg grating as a sensing layer and comprising an optical fiber and an external braiding layer, wherein a grating section with a set period is carved on a fiber core of the optical fiber, a polymer coating layer is coated on the surface of the optical fiber, the braiding layer and the optical fiber are subjected to multi-strand cross braiding according to a preset braiding angle, and axial tension can be linearly transferred to the optical fiber Bragg grating in proportion by controlling the braiding angle.
  2. 2. Tendon-like according to claim 1, further comprising a load-bearing fiber coaxially arranged with the optical fiber and a protective layer for protecting the tendon-like.
  3. 3. Tendon-like structure according to claim 1, wherein the weaving method is to perform multi-strand cross-weaving with the axis of the grating core material using aramid fiber or ultra-high molecular weight polyethylene fiber according to a predetermined weaving angle.
  4. 4. A driving-perception integrated rope driving device comprises the tendon-like, optical demodulation unit, driving execution unit and controller according to any one of claims 1 to 3, wherein: one end of the tendon-like body is connected with a driving source, the other end is connected with the load side; The optical demodulation unit is used for emitting light beams to the tendon-like beams and detecting the wavelength offset reflected by the fiber Bragg grating; the driving execution unit is used as a driving source and comprises a servo motor and a rope winding wheel; And the controller calculates the real tension in the tendon-like according to the wavelength offset through a preset wavelength-tension mapping model, and determines and adjusts the output of the servo motor by taking the real tension as a feedback signal so as to drive the rope winding wheel to rotate to compensate the tension deviation.
  5. 5. The apparatus of claim 4, wherein the tension bias is obtained according to the steps of: the controller receives the instruction of the upper computer and sets a target tension value ; The optical demodulation unit acquires the wavelength signal of the fiber Bragg grating in the tendon-like body in real time and converts the wavelength signal into the current real tension according to the preset wavelength-tension mapping model And real-time deviation value ; Calculating PID control parameters including a proportional parameter P, an integral parameter I and a differential parameter D; And outputting a control quantity to the servo motor according to the calculated PID control parameter so as to drive the rope winding wheel to rotate and compensate the tension deviation.
  6. 6. The apparatus of claim 4, wherein the wavelength-tension mapping model is calibrated according to the steps of: Establishing a mapping relation between the optical signal and the physical quantity: Wherein, the Is the axial tension force of the spring, Is the amount of wavelength shift that is present, Is the center wavelength of the fiber bragg grating, Is the strain of the tendon-like material, In order for the light-sensitive coefficient to be effective, Is a linear scaling factor, B is an intercept; Determination of tendon-like tendons at different tension by experiment Center wavelength offset below Fitting to obtain linear scale factor 。
  7. 7. The device according to claim 4, wherein the optical demodulation unit is an optical demodulator, and the optical fiber lines of a plurality of tendon-like bones are connected into different channels of the same optical demodulator, and the optical demodulation unit is applied to synchronous monitoring of tension of a plurality of finger joints or exoskeletons of a smart hand by scoring gratings with different center wavelengths on a single optical fiber.
  8. 8. The device of claim 7, wherein in a smart hand application, a single finger employs a separate tendon of the class to drive the distal, middle and proximal knuckles, respectively, to achieve real-time acquisition of the true internal forces of the distal, middle and proximal knuckle tendons to sense trans-articular tension.
  9. 9. The device according to claim 7, wherein after obtaining the tension information of the single tendon, the controller calculates and distributes the target torque of each servo motor according to the feedback of each degree of freedom and by combining with a kinematic model, so as to realize multi-axis torque distribution, impedance control or admittance control.
  10. 10. The apparatus of claim 4, further comprising controlling the drive execution unit to trigger a scram when the wavelength shift amount is detected to exceed a set threshold or a reflectance spectrum abnormality.

Description

Tendon-like and driving-sensing integrated rope driving device based on composite knitting structure Technical Field The invention relates to the technical field of high and new technology drivers, in particular to a tendon-like and driving-sensing integrated rope driving device based on a composite knitting structure. Background In a rope drive system, a flexible rope is usually drawn by a driving mechanism using high-strength fibers (such as aramid fibers, ultra-high molecular weight polyethylene fibers) or metals (such as carbon steel wires, stainless steel wires, galvanized steel wires, etc.) as a tension transmission medium. In order to realize force control and man-machine safety interaction of a rope drive system, such as an exoskeleton or a bionic drive system, a control system needs to acquire tension information in real time. Referring to fig. 1, the existing mainstream schemes include three types of methods of driving force measurement of fig. 1 (a), tension indirect measurement of fig. 1 (b), and tip contact force measurement of fig. 1 (c). In the driving force measuring method, the dragging force measurement of the driving mechanism depends on the motor driving current to estimate the output torque, but the method only calculates the equivalent force of the driving side and cannot reflect the real tension of the load side, namely calculation errors exist. Tension indirect measurement typically converts double sided rope tension changes to idler shaft forces or displacements through an idler mechanism, but this approach inevitably adds to the complexity of the structure, which is a challenge for internal control tight rope driven dexterous hand systems. The end contact force measurement relies on the force/touch sensor of the contact surface, but the method is only used for measuring the final operation result, and the real tension of a single-section driving rope cannot be obtained, which is important for a multi-rope driving system. The existing direct tension measurement is based on rigid deformation measurement of a resistance strain bridge, and the realization principle is that a resistance strain gauge is stuck on the surface of a stressed structural member (such as aluminum alloy and steel). After the structure is stressed, the member can generate trace strain and the strain gauge is deformed due to the adhesion and the fixation, the deformation of the strain gauge can bring resistance change, and finally the trace resistance change is converted into a voltage signal through a peripheral Wheatstone bridge circuit (full bridge, half bridge or quarter bridge). The limitation of the resistance strain bridge scheme is that the strain gauge is generally difficult to be applied to flexible objects such as tendon ropes (which cannot be adhered), and even if the strain gauge is small in size, the measurement accuracy is affected by easy falling off, creep and the like of an adhesive layer between the strain gauge and a base material under long-term cyclic load. In addition, strain gages are typically only capable of measuring single point stresses, and signal transmission lines are complex and unsuitable for long-distance, multi-node flexible rope drive systems. According to analysis, the existing method generally depends on a driving current estimation or a force/touch sensor with an external end, and has the following problems that the real internal force transmitted by a rope along a path cannot be obtained, the driving current is easily influenced by contact caused by friction, a guide wheel, cladding and the like, the driving perception is separated, the size is large, and the integration level is low. In the existing rope-driven exoskeleton or flexible driving device/system, the real tension in tendons (ropes) is difficult to directly, stably and accurately obtain, so that the application of high-efficiency control and man-machine safety interaction is blocked. In summary, the prominent disadvantage of the prior art is that the tension measurement is separated from the actual bearing path, and the integration degree of the sensing structure and the tendon is low. Thus, there is a need for a bulk drive-aware tendon-like material/assembly that can bear forces (enable driving), is sensitive to axial forces (enable sensing), and is suitable for closed-loop tension control. Disclosure of Invention The invention aims to overcome the defects of the prior art and provide a tendon-like and driving-sensing integrated rope driving device based on a composite knitting structure. According to a first aspect of the invention, there is provided a tendon-like body based on a composite braiding structure, the tendon-like body comprises an optical fiber and an external braiding layer, wherein the optical fiber uses an optical fiber Bragg grating as a sensing layer, a grating section with a set period is carved on the fiber core of the optical fiber, the surface of the optical fiber is covered with a polymer