Spacing-adjustable wrist four-channel flexible sensor of T-shaped groove structure

Abstract

The utility model provides a distance-adjustable wrist four-channel flexible sensor with a T-shaped groove structure. The distance-adjustable wrist four-channel flexible sensor comprises a T-shaped groove base and a sliding block part, the T-shaped groove base is formed by integrally cutting silica gel or rubber, and the surface of the T-shaped groove base is subjected to hard anodic oxidation treatment; a flexible sensing unit is arranged at the top of the sliding block part and is made of a piezoelectric elastomer material; a hard substrate is arranged below the flexible sensing unit, an inverted-T-shaped sliding block is arranged below the hard substrate, and the inverted-T-shaped sliding block is in clearance fit with the T-shaped groove base. Longitudinal pressure is controlled by adjusting screws at the bottoms of the sliding blocks, continuous adjustment of the four-channel sensor within the stroke range of 350 mm is achieved, and the four-channel sensor meets the wearing requirements of people with the wrist girth ranging from 150 mm to 250 mm. The solid lubricant is sprayed on the matching interface of the inverted-T-shaped sliding block and the T-shaped groove, the dynamic friction coefficient of the interface is obviously influenced by the longitudinal pressure change, and the self-locking thread angle is matched, so that the spontaneous displacement of the sliding block is smaller and the locking state is kept better under the working conditions of small-frequency and small-range random vibration.

Description

Technical Field

[0001] This utility model relates to the field of wearable sensing technology, and in particular to an adjustable-spacing four-channel flexible wrist sensor with a T-groove structure. It is especially suitable for scenarios that require dynamic adaptation to the size of the human wrist and high-precision synchronous acquisition of multi-channel biosignals (such as electromyography, pressure, and vibration), including medical rehabilitation monitoring, motion posture analysis, and human-computer interaction control. Background Technology

[0002] Currently, wearable wrist sensors are widely used in medical monitoring, motion analysis, and other fields, but there is still a significant gap between their design and actual needs. Traditional fixed wristband sensors mostly use a pre-embedded array design, and the sensor spacing cannot be adjusted, resulting in limited adaptability. For example, electrodes or piezoelectric films with fixed spacing are difficult to adapt to different wrist circumferences or specific detection targets (such as differences in tendon spacing), and dense arrangement can easily cause signal crosstalk between channels. More seriously, such devices often use rigid circuit boards, whose elastic modulus differs too much from that of human skin. During movement, mechanical mismatch causes shearing effects, resulting in a large signal distortion rate.

[0003] To improve compatibility, some solutions use elastic, stretchable wristbands, passively adjusting the sensor position through stretching. However, elastic deformation causes random sensor misalignment, resulting in significant repeatability errors, and the material's resilience decreases after thousands of stretching cycles. Furthermore, uneven pressure between the sensor and skin under stretching conditions leads to noticeable fluctuations in contact impedance, severely impacting signal stability. While these solutions alleviate compatibility issues, they sacrifice accuracy and reliability.

[0004] Another type of modular design attempts to achieve active adjustment through mechanical structures (such as slide rails and locking teeth). For example, while a solution using miniature aluminum alloy slide rails with locking screws allows for manual adjustment, it requires special tools for tightening, making the operation cumbersome and significantly increasing weight. While ratchet locking mechanisms support incrementing adjustments, the minimum adjustment precision is only 1mm, and frequent adjustments cause wear on the teeth. More importantly, rigid adjustment components are incompatible with flexible wrist movements, resulting in poor wearing comfort, and the non-sealed structure is prone to metal corrosion under sweat, failing to meet the needs of wearable devices.

[0005] In summary, existing solutions have failed to resolve the inherent conflict between the "flexible sensing requirements" and the "rigid adjustment structure." This invention therefore proposes a composite structure based on a T-slot, which overcomes the technical bottlenecks in adaptability, accuracy, and reliability through the synergistic design of a flexible substrate and a rigid adjustment unit. Utility Model Content

[0006] To address the issues of portability, adaptability to different groups, and cost in existing technologies, this invention proposes a T-groove structure adjustable spacing four-channel flexible wrist sensor, which has the advantages of adaptability to multiple groups, lightweight portability, and accurate recognition.

[0007] The technical solution adopted in this utility model is as follows:

[0008] An adjustable-spacing four-channel flexible wrist sensor with a T-slot structure, comprising a T-slot and a slider portion;

[0009] The T-groove section is integrally machined from human-contact silicone / rubber and its surface is hard anodized to improve wear resistance.

[0010] Cross-sectional dimensions: 200×40mm; pre-drilled screw holes at the bottom.

[0011] The slider portion consists of a flexible sensing unit at the top, which can be made of piezoelectric elastomer materials such as PVDF or LBPE. Below this is a rigid substrate made of aluminum alloy. Both components are the same size, 30×40mm. The bottom part is made of glass fiber reinforced material to form an inverted T-shaped structure, with a 0.2mm gap between the inverted T-shaped structure and the T-slot. (The inverted T-shaped structure is made of a material with higher hardness and strength than the T-slot, which reduces the interface damping coefficient between the T-slot and the inverted T-shaped structure, thus making the sliding smoother.)

[0012] In one embodiment, the sensor is packaged using flexible TPU with an elastic modulus similar to that of human skin. This reduces the foreign body sensation when in contact with the skin and weakens the secondary shearing effect, which can make the data measurement more accurate and improve the signal quality.

[0013] In one embodiment, the bottom of the T-slot has a screw hole and a screw-carrying slide for locking and sliding the slider. The locking and sliding mechanism will be analyzed below. When the screw at the bottom of the slider is tightened using a handwheel or screwdriver, the T-slot deforms downwards, generating longitudinal pressure on the bottom of the slider. This increases the friction between the T-slot and the bottom of the slider, locking the slider in the corresponding position. By loosening the screw, the longitudinal pressure on the bottom of the slider is reduced, resulting in a decrease in friction between the T-slot and the bottom of the slider, allowing it to move and thus adjust the sensor spacing. Simultaneously, a limiting block is added to the bottom of the groove to restrict the slider's sliding within a certain area. The adjustable range of each slider is 350mm.

[0014] In one embodiment, a disc spring assembly is provided inside the slider. When the spring is compressed in the locked state, it generates axial damping, which attenuates the transmission of vibration.

[0015] In one implementation, threaded lubricant is sprayed (or a reinforcing bushing is used), in conjunction with a self-locking angle, to ensure that the slider has no spontaneous displacement in the locked state.

[0016] In one implementation, a flexible printed circuit (FPC) interface is used for the electrical connection between the sensor and the signal processing module, combined with conductive adhesive and through-hole electrodes to improve connection strength and signal integrity.

[0017] Taking PVDF as an example, the working principle of the flexible sensing unit is briefly described below: Under the action of external force, PVDF undergoes microscopic deformation (compression or stretching), changing the dipole spacing of the molecular chains and generating charge separation. Surface charges are collected by metal electrodes (such as silver nanowires or ITO coatings) attached to both sides of the PVDF, forming measurable voltage or current signals. The strength of the output electrical signal is proportional to the magnitude of the applied mechanical stress, achieving precise quantification of external force / deformation.

[0018] This application primarily relates to the structure and functional implementation of flexible piezoelectric sensors (such as polyvinylidene fluoride sensors). However, those skilled in the art should understand that, under the condition of meeting the preset sensing performance and adaptability requirements, other types of flexible sensors (including but not limited to piezoresistive, capacitive, or photoelectric sensors) can be applied to the described technical solution through equivalent substitutions, and such substitutions should be considered equivalent implementations within the scope of the claims of this patent. The above-mentioned technical features can be combined in various suitable ways or replaced by equivalent technical features, as long as the purpose of this utility model can be achieved.

[0019] The adjustable-spacing four-channel flexible wrist sensor with a T-groove structure provided by this utility model has at least the following advantages compared with the prior art:

[0020] 1. The adjustable spacing wrist sensor structure adopts a mechanical cooperation design of T-slot and inverted T-shaped slider. The longitudinal pressure is controlled by adjusting the screw at the bottom of the slider, so as to realize the continuous adjustment of the four-channel sensor within a stroke range of 350mm, which is suitable for the wearing needs of people with wrist circumference of 150-250mm.

[0021] 2. The base is integrally machined from contactable silicone / rubber (meeting biocompatibility standards), and the surface is treated with hard anodizing. Combined with glass fiber reinforced inverted T-shaped sliders, the overall weight is reduced by more than half compared with the traditional aluminum alloy base solution, and the elasticity is also significantly improved. At the same time, it has an effective small surface damping coefficient.

[0022] 3. The interface between the inverted T-shaped slider and the T-slot is coated with a solid lubricant. The dynamic friction coefficient of the interface is significantly affected by the longitudinal pressure change. With the matching self-locking thread angle, the spontaneous displacement of the slider is small under low frequency and small range random vibration conditions, and the locking state is well maintained. Attached Figure Description

[0023] The present invention will be described in more detail below based on embodiments and with reference to the accompanying drawings. Wherein:

[0024] Figure 1 Left view of the structural design;

[0025] Figure 2 Bottom diagram of the structural design;

[0026] Figure 3 A three-dimensional perspective view of the overall structure;

[0027] Explanation of reference numerals in the attached figures:

[0028] 100: T-slot base; 101: Flexible sensing unit; 102: Rigid substrate; 103: Inverted T-shaped slider; 104: Adjusting screw; 105: Screw protective layer; 106: Connecting layer; 107: Threaded mounting hole; 108: Flexible printed circuit (FPC). Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings.

[0030] This utility model provides an adjustable spacing wrist four-channel flexible sensor with a T-slot structure, including a T-slot base 100 and a slider part;

[0031] The T-slot base 100 is integrally machined from contact-grade silicone / rubber (meeting biocompatibility standards), with a cross-sectional dimension of 200×40mm. The surface is hard anodized. Threaded mounting holes 107 are evenly distributed at the bottom of the slot, with a hole spacing of 50mm±0.1mm. Extended threaded slideways are provided at both ends of the base, with built-in limit block assemblies limiting the slider's movement range to 0-350mm.

[0032] Adjustment Mechanism: The slider part has a split structure. The upper flexible sensing unit 101 is made of PVDF piezoelectric film or LBPE elastomer, and the surface is covered with a flexible TPU encapsulation layer. The lower rigid base 102 is formed by processing aluminum alloy (size 40mm×30mm×5mm). The bottom is bonded with epoxy resin to a glass fiber reinforced inverted T-shaped slider 103 (cross-sectional size 38mm×28mm), and the fit clearance between it and the T-slot is 0.2mm. An adjusting screw 104 is embedded at the bottom of the slider. By applying torque to drive the screw to press down, the inverted T-shaped slider 103 and the side wall of the T-slot base 100 generate a longitudinal locking force, and the coefficient of friction changes from 0.05 in the sliding state to 0.9 in the locked state, thereby fixing the position.

[0033] In one embodiment, there is a screw protection layer 105 below the screw hole, which covers the screw hole when fixed, improving wearing comfort.

[0034] Figure 2 The connecting layer 106 is used to connect the end of the overall structure into a ring, so that it can be worn on the wrist for functional application.

[0035] Damping and protection design: Solid lubricant is sprayed on the contact surface between the inverted T-shaped slider and the T-slot, and with the self-locking thread design, the spontaneous displacement of the slider is almost zero during random vibration at low frequency and small amplitude.

[0036] Electrical connection and signal processing: Each sensing unit is connected to the processing module through a flexible printed circuit 108. The FPC interface uses conductive silver paste and through-hole electrodes to achieve low impedance transmission.

[0037] Operating procedures:

[0038] Adjustment stage: First open the screw protective layer 105, loosen the adjusting screw 104 at the bottom of the slider. At this time, the interface friction coefficient is reduced. Slide the slider to the target position.

[0039] Locking stage: Use a torque screwdriver to tighten the adjusting screw 104. The screw generates interference pressure in the radial direction, while the disc spring contracts to form axial damping, increasing the surface damping coefficient of the slider and the base, thereby locking the slider in the current position.

[0040] Signal acquisition: The four-channel piezoelectric signals are transmitted to the processing module via the flexible printed circuit 108 for further processing.

[0041] This invention achieves synergistic optimization of wearability, signal accuracy, and environmental tolerance through a precise matching mechanism between a T-shaped groove and an inverted T-shaped slider, combined with a flexible biocompatible design of the silicone base. Specifically, the structure supports continuous adjustment of 350mm stroke, adapting to individuals with wrist circumferences of 150-250mm; the combination of the biocompatible silicone base and the lightweight glass fiber reinforced slider significantly reduces weight; regarding signal quality, the synergistic damping design of the TPU encapsulation layer and the disc spring assembly greatly suppresses crosstalk in the four-channel signal and minimizes signal fluctuations under low-frequency, low-amplitude random vibrations. This provides an innovative flexible sensing solution with both high precision and high adaptability for fields such as medical rehabilitation monitoring and sports biomechanical analysis.

[0042] While specific embodiments of the present invention have been described herein with reference to them, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.

Claims

1. A T-slot structure adjustable pitch wrist four-channel flexible sensor, characterized in that, It comprises a T-shaped groove base (100) and a slider part; The T-shaped groove base (100) is integrally cut and formed by silica gel or rubber, and the surface is treated by hard anodizing; The top of the slider part is a flexible sensing unit (101) made of piezoelectric elastomer material; below the flexible sensing unit (101) is a hard base (102), and below the hard base (102) is an inverted T-shaped slider (103) which is in clearance fit with the T-shaped groove base (100).

2. The adjustable pitch T-slot structured four-channel flexible sensor wrist according to claim 1, wherein, The bottom of the T-shaped groove base (100) is uniformly distributed with threaded mounting holes (107).

3. The adjustable pitch T-slot structured four-channel flexible sensor wrist according to claim 1, wherein, The flexible sensing unit (101) is made of PVDF piezoelectric film or LBPE elastomer, and the surface is covered with a flexible TPU packaging layer.

4. The adjustable pitch T-slot structured four-channel flexible sensor wrist according to claim 1, wherein, The hard base (102) is processed by aluminum alloy.

5. The adjustable pitch T-slot structured four-channel flexible sensor wrist according to claim 4, wherein, The hard base (102) is bonded with the inverted T-shaped slider (103) by epoxy resin.

6. The adjustable pitch T-slot structured four-channel flexible sensor wrist according to claim 1, wherein, The bottom of the inverted T-shaped slider (103) is embedded with an adjusting screw (104), which can adjust the longitudinal locking force of the inverted T-shaped slider (103) and the T-shaped groove base (100).

7. The adjustable pitch T-slot structured four-channel flexible sensor wrist according to claim 6, wherein, Below the adjusting screw (104) is a screw protection layer (105).

8. The adjustable pitch T-slot structured four-channel flexible sensor wrist according to claim 1, wherein, The contact surface of the inverted T-shaped slider (103) and the T-shaped groove base (100) is sprayed with a solid lubricant, which cooperates with the self-locking thread of the adjusting screw (104) to reduce the spontaneous displacement of the slider.

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