Autonomous regulation type PPG detection device and control method thereof

Abstract

The invention relates to an autonomous regulation and control type PPG detection device and a control method thereof. The autonomous regulation and control type PPG detection device comprises a mechanical execution module, an optical detection module, a pressure sensing module and a controller, the mechanical execution module comprises a force actuator and a conduction assembly, the conduction assembly is of a three-layer rigid-flexible gradual change structure and comprises an outer layer, a middle layer and an inner layer, and the force actuator is fixed to the conduction assembly; the optical detection module comprises a light source assembly and a photoelectric receiver; the pressure sensing module comprises at least one pressure sensor which is arranged on the middle layer or the inner layer of the conduction assembly in a flat attaching mode or an embedded mode. The input end of the controller is connected with the output ends of the pressure sensor and the photoelectric receiver, and the output end of the controller is connected with the input ends of the force actuator and the light source assembly. According to the invention, a closed-loop cooperative working mechanism of autonomous pressure regulation and optical compensation is introduced, so that the coverage of all application scenes such as static / dynamic scenes, consumption wearing / medical detection and the like is realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of photoplethysmography (PPG) detection, and particularly relates to an autonomously regulated PPG detection device and its control method, which are applicable to application scenarios such as wearable devices and clinical monitors that require continuous monitoring of physiological parameters such as heart rate, blood oxygen, and blood pressure. Background Art

[0002] The photoplethysmography (PPG) technology is a non-invasive physiological signal detection method based on optical principles. By emitting light of a specific wavelength (such as red light or infrared light) to the skin tissue and detecting the periodic changes in the reflected or transmitted light intensity, key physiological parameters such as heart rate and blood oxygen saturation can be extracted. Due to its advantages such as non-invasiveness, low cost, and portability, this technology has been widely applied in the fields of clinical monitoring, wearable devices, and health management. Traditional PPG sensors mainly include core components such as a light source (LED or laser diode), a photoelectric receiver (such as a photodiode), and a signal processing module. Their structural forms cover various designs such as finger clip type, wrist-worn type, and patch type, but still face many challenges in practical applications.

[0003] Existing PPG sensors have significant technical limitations: First, the traditional rigid finger clip structure relies on mechanical structures (such as elastic materials or rigid structures) to provide passive pressure or static maintenance solutions, which can neither dynamically adjust according to individual differences of users or usage scenarios, nor is it easy to cause blood vessel compression and deformation and signal distortion due to excessive pressure, or poor optical path coupling and decreased signal-to-noise ratio due to insufficient pressure; Second, although wearable PPG (such as a flexible patch design) improves wearing comfort, due to the lack of an effective pressure feedback and adjustment mechanism, it is easily affected by skin sliding during user movement, resulting in serious motion artifacts (the signal-to-noise ratio decreases significantly during strenuous exercise), and existing solutions mostly rely on post-algorithm filtering and are difficult to solve the problem of optical path instability at the hardware level; In addition, the adaptability of the existing structure is poor, and it can neither be compatible with the finger diameter differences of special populations such as children and edematous patients, nor does the plastic deformation after long-term use of elastic materials (elastic materials such as silicone may experience pressure decay after repeated compression) lead to continuous deterioration of measurement accuracy; Problems such as environmental sensitivity (such as thermal expansion and contraction of materials caused by temperature changes) and insufficient light shielding performance further restrict the reliability of PPG technology. These defects severely limit its application value in medical-grade high-precision monitoring and dynamic motion scenarios, and there is an urgent need for an innovative solution that can synergistically optimize pressure control, motion suppression, and environmental adaptability. Summary of the Invention

[0004] The object of the present invention is to provide an autonomous regulation type PPG detection device and its control method. In the traditional method, the use of a fixed pressure or a passive elastic structure cannot adapt to complex usage scenarios. However, through an innovative closed-loop control mechanism that combines pressure sensing and adaptive active regulation, the present invention dynamically maintains the optimal contact pressure while synchronously optimizing light source compensation, thereby improving the signal quality and providing solutions for complex application scenarios and individual differences.

[0005] An autonomous regulation type PPG detection device proposed by the present invention includes an optical detection module, a pressure sensing module, a mechanical execution module, and a controller; the mechanical execution module includes a force actuator and a conduction component; wherein: The conduction component is a rigid-flexible gradient structure, adopting a three-layer gradient structure, including an outer layer, a middle layer, and an inner layer; the inner wall of the outer layer is a black structure, the inner wall of the outer layer is connected to the outer wall of the middle layer, the inner wall of the middle layer is connected to the outer wall of the inner layer, and a cavity is provided inside the inner layer for accommodating the object to be measured; the outer layer, the middle layer, and the inner layer form a mechanical conduction path pointing to the object to be measured; the inner layer also serves as an optical coupling interface; the stiffness of the conduction component decreases along the contact direction of the object to be measured; the outer layer is a rigid frame, the middle layer is an elastic layer, and the inner layer is a flexible layer; the inner wall of the rigid outer layer adopts a black light-absorbing structure to form a black inner wall, and a cavity is provided inside for supporting the light source component, the photoelectric receiver, and the force actuator; the middle layer adopts a light-transmitting elastic buffer material, and its elastic modulus is between that of the outer layer and the inner layer; the inner layer adopts a light-transmitting and adhesive high-flexible material to form a contact interface with the object to be measured, which is both a mechanical conduction terminal and an optical coupling interface; the conduction component receives the force from the force actuator and transmits the pressure to the object to be measured. The optical detection module includes a light source component and a photoelectric receiver. The PPG detection device adopts a transmissive or reflective structure. When it is a transmissive structure, the light source component and the photoelectric receiver are located on both sides of the object to be measured, that is, the light source component is located on the outer layer of the conduction component, and the photoelectric receiver is located on the outer layer of the conduction component. The light source component emits light waves towards the object to be measured, and the photoelectric receiver receives the optical signal from the object to be measured; when it is a reflective structure, the light source component and the photoelectric receiver are located on the same side of the object to be measured, that is, both the light source component and the photoelectric receiver are located on the outer layer of the conduction component. The pressure sensing module includes at least one pressure sensor, which is arranged on the conduction component in a flat-attached or embedded manner. Each pressure sensor is connected to the controller, and the pressure sensing module transmits data to the controller as an adjustment reference. The mechanical execution module includes a force actuator and a conduction component; the force actuator is fixed to the outer layer or the inner layer of the conduction component; the conduction component receives the force from the force actuator and transmits the pressure to the object to be measured. The signal acquisition module includes a front-end conditioning circuit (AFE) and an analog-to-digital conversion circuit (ADC), which receive and preprocess the signals from the pressure sensing module and the optical detection module and convert them into digital signals; the processing module receives the digital signals from the signal acquisition module and executes the pressure-light intensity collaborative control method; the output module converts the instructions of the processing module into hardware-executable instructions, and drives the collaborative actions of the actuator, the outer layer, the middle layer, the inner layer, and the light source component to adjust / maintain the optimal detection state. The specific logic diagram is as shown in Figure 2 shown.

[0006] The controller includes a signal acquisition module, a processing module, and an output module; the signal acquisition module includes a pressure signal acquisition channel and an optical signal acquisition channel. The pressure signal acquisition channel includes a first front-end conditioning circuit connected to the output end of the pressure sensor and a first analog-to-digital conversion circuit connected thereto. The optical signal acquisition channel includes a second front-end conditioning circuit connected to the output end of the photoelectric receiver and a second analog-to-digital conversion circuit connected thereto. The two channels independently receive and preprocess the signals from the pressure sensor and the optical detector and convert them into digital signals; the processing module receives the digital signals from the signal acquisition module and executes the pressure-light intensity collaborative control method. The output end of the processing module is respectively connected to the input ends of the force actuator and the light source component. The processing module receives the pressure sensing data of the pressure sensor, calculates and generates a pressure adjustment instruction and outputs it to the output module. The processing module receives the PPG optical data, calculates and generates a corresponding light intensity compensation instruction and conveys it to the output module; the output module converts the instructions of the processing module into hardware-executable instructions, drives the collaborative actions of the force actuator, the outer layer, the middle layer, the outer layer, and the light source component, and adjusts / maintains the optimal detection state.

[0007] In the present invention, the force actuator is located in the mechanical transmission path and is a physical component that adjusts the contact pressure by changing at least one of the geometric configuration, spatial position, or material properties of the structure. Specifically, a scissor-type telescopic mechanism, a dielectric elastomer material, or a micro-pneumatic cavity array can be adopted to dynamically adjust the contact pressure by changing the spatial position or shape of the conduction component. The specific implementation manner of the controllable deformation is not limited to any technical means that can achieve controllable changes, such as mechanical adjustment or intelligent drive.

[0008] In the present invention, the light source component includes at least one LED light source, preferably an integrated multi-wavelength LED light source array, and the light source is preferably green or infrared wavelength. The photodetector includes a silicon photodiode or a similar photosensitive element.

[0009] A control method for an autonomously regulated PPG detection device proposed by the present invention is as follows: After the PPG detection device is started, initial pressure calibration is first performed and basic light intensity parameters are established. Subsequently, during the detection process, the contact pressure change and the optical signal quality are monitored in real time. When the contact pressure detected by the pressure sensing module deviates from the preset range, the controller comprehensively judges the pressure state and the PPG optical signal characteristics, generates optimal adjustment parameters, and transmits the instructions to the force actuator. The force actuator responds to the drive, adjusts the contact pressure between the PPG detection device and the object to be measured by deformation, and cooperates with the inner layer viscous characteristics of the conduction component to maintain the best fitting state; the adjustment process adopts a progressive method, mainly adjusting the pressure first, and when the pressure enters the stable range, then fine-tuning the light intensity to optimize the signal quality. After each adjustment, the improvement of the PPG signal is evaluated until a stable detection state is reached; this active adjustment closed-loop control method can sense the change trend of the contact pressure in real time, respond quickly and maintain the best contact state, and can effectively solve the signal quality problems caused by individual differences, changes in motion state, and environmental factors.

[0010] In the present invention, the control method further includes an exception handling mechanism. When continuous exceptions are detected, a hierarchical protection program is started: in the initial stage, priority is given to restoring the safe contact state by gradually reducing the pressure; when the pressure adjustment cannot improve the signal quality, it automatically switches to the light intensity compensation mode and dynamically adjusts the light source output power; if the abnormal state persists, a safe sleep mechanism is triggered. The entire process maintains the coordinated operation of pressure adjustment and light compensation to ensure the safety of use and the effectiveness of measurement.

[0011] The beneficial effects of the present invention are as follows: The present invention proposes an actively adaptive PPG detection system, aiming to solve the following technical problems: (1) signal quality problems caused by passive pressure; (2) signal instability under dynamic conditions; (3) adaptability problems in different usage environments and individual differences; (4) technical limitations of traditional passive compensation. The present invention has achieved many beneficial effects as follows, specifically as follows: First of all, the closed-loop pressure self-adjustment device of the present invention solves the long-existing "pressure adaptation dilemma" in the industry. The device can dynamically solve two extreme situations - too small pressure (resulting in poor optical path coupling and decreased signal-to-noise ratio) and too large pressure (causing blood vessel compression and deformation and signal distortion), and by always maintaining the contact pressure in the best detection interval, thereby ensuring the accuracy of basic signal acquisition. This basic innovation provides a source guarantee for all subsequent technical effects.

[0012] Secondly, the pressure-light intensity coordinated control device solves the multiple interference problems of traditional PPG in dynamic scenes: (1) Macro-motion compensation: eliminates contact pressure fluctuations caused by running, fitness and other sports to ensure signal acquisition stability; (2) Micro-displacement suppression: reduces motion artifacts caused by sensor micro-displacement through a pressure maintenance mechanism, and maintains signal continuity in clinical turning, transfer and other scenarios; (3) Environmental adaptation: in response to interface changes such as sweating, the contact pressure and light source parameters are adjusted synchronously to form a guarantee in a dynamic environment.

[0013] Furthermore, the present invention achieves the adaptation of the same device to different groups of people through an innovative hierarchical control strategy: (1) Adaptation for the entire population: automatically matching the optimal pressure-light intensity combination for different groups such as children, the elderly, and hypertensive patients; (2) Scenario adaptation: automatically adjusting the pressure cycle during long-term monitoring, and compensating for the impact of material deformation in real time when the environment changes; (3) Safety upgrade: establishing a pressure safety threshold for sensitive groups to avoid medical risks.

[0014] In terms of technical approach, this invention proactively maintains optimal contact during the signal acquisition phase, ensuring signal quality control from the source. Compared to existing PPG technologies that rely on post-processing algorithmic compensation such as motion artifact elimination, auxiliary interference identification methods such as inertial sensors, or optical hardware upgrades, which rely on a "degrade first, repair later" passive response strategy, this invention's shift from "passive remediation" to "active prevention" not only simplifies the device architecture but also effectively reduces reliance on complex algorithms. By introducing a collaborative mechanism between a closed-loop autonomous pressure control device and optical compensation, this invention achieves coverage for a full range of application scenarios, including static / dynamic scenarios, consumer wearables, and medical testing. This creates a new development paradigm for PPG testing technology that is simpler, more reliable, and more efficient. This series of innovations not only addresses the pain points of existing technologies but also points the way for technological advancement in the industry.

[0015] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purposes and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of an adaptive PPG device according to Example 1 of the present invention; (A) is a left view, and (B) is a front view; Figure 2 This is a controller logic diagram shown in Example 1 of the present invention; Figure 3 Schematic diagram of device adjustment when pressure is insufficient and pressure is excessive in Example 1 of the present invention; Figure 4 Flow chart of the closed-loop control method for autonomous pressure regulation in Embodiment 1 of the present invention; Figure 5 Flow chart of the safety mechanism for autonomous pressure regulation in Embodiment 1 of the present invention; Figure 6 Self-adaptive PPG device diagram shown in Embodiment 2 of the present invention; wherein: (A) is the left view, and (B) is the front view; Figure 7 Self-adaptive PPG device diagram shown in Embodiment 3 of the present invention; wherein: (A) is the left view, and (B) is the front view; Figure 8 Self-adaptive PPG device diagram shown in Embodiment 4 of the present invention; wherein: (A) is the left view, and (B) is the front view; Figure 9 Self-adaptive PPG device diagram shown in Embodiment 5 of the present invention; wherein: (A) is the left view, and (B) is the front view; Reference numerals in the figure: 1 is the cavity, 2 is the light source assembly, 3 is the photoelectric receiver, 4 is the force actuator, 5 is the pressure sensor, 6 is the inner layer, 7 is the intermediate layer, 8 is the outer layer, 9 is the conduction assembly, and 10 is the black inner wall. Detailed implementation manners

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings introduced below are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can also be obtained based on these drawings.

[0018] It should be clear that the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0019] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms of "a", "the", and "said" used in the embodiments of the present invention and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0020] It should be understood that the term " / and / or" used herein is only a description of the associated relationship of the associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this text generally represents an "or" relationship between the associated objects before and after. Embodiment 1

[0021] A finger clip type PPG detection device with an autonomous pressure regulation function, the schematic structural diagram of which is as Figure 1 shown; the device includes: an optical detection module, a mechanical execution module, a pressure sensing module and a controller; the optical detection module includes a light source assembly 2 and a photoelectric receiver 3, the light source assembly 2 emits light waves to the object to be measured, and the photoelectric receiver 3 receives the optical signal from the object to be measured; The mechanical execution module includes a conduction assembly 9 and a force actuator 4; The conduction assembly 9 is a rigid-flexible gradient structure, and its stiffness continuously decreases along the skin contact direction; preferably, a 3-layer gradient structure is adopted, including a rigid outer layer 8, an elastic intermediate layer 7 and a flexible inner layer 6; the rigid outer layer 8 is a stability frame and is provided with a black light-absorbing structure for supporting the light source assembly 2, the photoelectric receiver 3, the force actuator 4, etc.; the intermediate layer 7 includes a light-transmitting elastic buffer material, and its elastic modulus is between the outer layer 8 and the inner layer 6; the inner layer 6 includes a highly flexible light-transmitting adhesive material, which constitutes the contact interface with the skin, and it is both the mechanical conduction terminal and the optical coupling interface; the conduction assembly 9 receives the force from the force actuator 4 and transmits the pressure to the part to be measured; The force actuator 4 is integrated into the mechanical transmission path of the device and is a physical component that realizes contact pressure adjustment by changing at least one of the geometric configuration, spatial position or material properties of the structure; a scissor-type telescopic mechanism is adopted to realize the dynamic adjustment of the contact pressure by changing the spatial position or shape of the conduction assembly; the specific implementation method of the controllable deformation is not limited to any technical means that can realize controllable changes such as mechanical adjustment or intelligent drive; The inside of the housing of the device is a cavity 1 for accommodating the finger to be detected; The optical detection module includes a light source assembly 2 and a photoelectric receiver 3; wherein, the light source assembly 2 includes at least one LED light source, preferably an integrated multi-wavelength LED light source array, and the light source is preferably green light or infrared wavelength; the photodetector 3 includes a silicon photodiode coupled with a narrow-band optical filter; according to the relative positions of the light source assembly 2 and the photoelectric receiver 3, PPG can be divided into transmissive and reflective types; in this specific embodiment, a transmissive PPG structure is preferably adopted. When the finger is placed in the cavity 1, the light source assembly 2 and the photoelectric receiver 3 are respectively located above and below the finger; The force actuator 4 works in cooperation with the controller to realize the autonomous dynamic adjustment of the contact pressure between the detection device and the skin; The conduction assembly 9 is a rigid-flexible gradient structure, and its stiffness continuously decreases along the skin contact direction to realize stress buffering; The force actuator 4 adopts a micro scissor mechanism, which generates a planar displacement through the expansion of a rhombic unit; The conduction component 9 is preferably a three-layer composite structure with gradient stiffness. Through the synergistic effects of the rigid support of the outer layer 8, the flexible transition of the middle layer 7, and the ultra-flexible contact of the inner layer 6, the pressure adaptation problem is solved synchronously and the optical coupling efficiency is improved; The outer layer 8 uses a rigid frame to provide overall structural stability. Positioning grooves are respectively provided on the upper and lower sides of its inner wall to fix the light source component 2 and the photoelectric receiver 3; the side inner wall is rigidly connected to the force actuator 4; the inner wall of the outer layer 8 adopts a black inner wall cabinet structure to shield environmental light noise; The middle layer 7 selects a light-transmitting material as the mechanical buffer medium. Its elastic modulus is between the rigid frame of the outer layer and the flexible interface of the inner layer, so as to reduce the pressure wave energy dissipation and the risk of structural failure caused by the sudden change of interface stiffness; As the functional interface in direct contact with the skin, the inner layer adopts a light-transmitting flexible adhesion surface to achieve dual synergistic effects: in the mechanical dimension, the external rigid load is buffered by the material flexibility, and the pressure is evenly distributed by combining the surface adhesion characteristics; in the optical dimension: the air gap is eliminated by the intimate fit of the interface, reducing the optical path transmission loss; The conduction component 9 is used to convert the mechanical displacement of the scissor mechanism into a pressure distribution suitable for soft tissue contact; The basic structure of the scissor mechanism is composed of two or more groups of cross-hinged connecting rods connected in series through a common rotating shaft. The telescopic movement and direction conversion are realized by changing the angle between the connecting rods; In this embodiment, the scissor mechanism is located on the inner side of the rigid outer layer, and the movement direction is restricted by the vertical guiding constraint component; The bottom of the scissor mechanism is fixed to the outer rigid frame, and this frame and the fixed component on the dorsal side of the finger jointly constitute the reaction force bearing skeleton; the top is coupled to the rigid outer layer through the elastic middle layer, which is used to absorb the high-frequency mechanical vibrations transmitted from the system interior and the random micro-vibrations generated by finger joint activities; During operation, the scissor mechanism, under the action of electric drive, pushes the rigid outer layer to generate a vertical displacement, and then adjusts the contact pressure between the inner layer and the skin through the deformation conduction of the middle elastic layer; The pressure sensing module includes at least one pressure sensor, which is located inside the conduction component; In this embodiment, the pressure sensor adopts a capacitive pressure sensor array, preferably arranged on the inner wall surface of the rigid outer layer, and its sensing surface is flush with the inner surface of the outer layer; The signal transmission line of the pressure sensor is routed through the preset routing channel on the inner wall of the rigid layer, and anti-reflection treatment is performed on the components that may interfere with optical detection; To avoid the optical detection paths above and below, the pressure sensors are arranged on the left and right sides of the finger, and multiple sensor units are arranged in a symmetric array form; The pressure data collected by the pressure sensor can be used for: monitoring the pressure range and evaluating the contact quality of the optical window; the specific application method will be described in detail in the control method section; The controller includes a signal acquisition module, a processing module, and an output module; The signal acquisition channel consists of a first front-end conditioning circuit (AFE) connected to the output end of the pressure sensor and a first analog-to-digital conversion circuit (ADC) connected thereto. The optical signal acquisition channel consists of a second front-end conditioning circuit connected to the output end of the optical receiver and a second analog-to-digital conversion circuit connected thereto. The two channels independently receive and preprocess the signals of the pressure sensor and the optical detector, and convert them into digital signals; The processing module receives the digital signals from the signal acquisition module and executes the pressure-light intensity collaborative control method. The output end of the processing module is respectively connected to the input ends of the force actuator and the light source assembly. The processing module receives the pressure sensing data of the pressure sensor, calculates and generates a pressure adjustment instruction and outputs it to the output module. The processing module receives the PPG optical data, calculates and generates a corresponding light intensity compensation instruction and outputs it to the output module; The output module converts the instructions of the processing module into instructions executable by the hardware, and drives the collaborative action of the force actuator, the outer layer, the middle layer, the outer layer of the conduction component, and the light source assembly to adjust to / maintain the optimal detection state. The specific logic diagram is as Figure 2 shown.

[0022] The controller monitors the contact pressure and the optical signal quality in real time, and dynamically adjusts the force actuator, the conduction component, and the light source based on a predefined collaborative control strategy, and this multi-modal collaborative mechanism realizes the dynamic balance between optical detection and contact pressure; In the initialization stage, a pressure-optical parameter correlation model is constructed, and this model defines the adjustment strategies of the actuator corresponding to different pressure intervals; In the operation stage, the detection device synchronously processes the optical detection signal and the pressure sensing data in real time, and dynamically adjusts the mechanical output and the light source driving intensity through a closed-loop control method; the pressure sensing module continuously monitors the pressure distribution state of the contact interface, and the system adjusts the force actuator accordingly to maintain the optimal working pressure range; synchronously, the detection device analyzes the characteristic changes of the output signal in real time. When the signal quality deterioration is detected, it automatically judges the current pressure state and triggers the corresponding adjustment strategy, such as Figure 3 and Figure 4 shown; When the detected contact pressure is lower than the set threshold, the detection device adopts a progressive pressurization method to improve the optical coupling efficiency, and evaluates the improvement degree of the signal quality after each pressure adjustment; during this process, the optical signal amplitude and waveform characteristics are monitored synchronously. When the signal amplitude is detected to be close to the saturation threshold, the light source driving current is automatically adjusted downwards to avoid signal distortion; When the pressure enters the stable working range, the detection device maintains the stable state of the basic control parameters and only makes compensatory adjustments for minor deviations caused by environmental fluctuations; When the contact pressure is detected to be higher than the set threshold, the detection device initiates a step-by-step pressure reduction process to gradually reduce the force applied by the force actuator. This process simultaneously monitors the trend of changes in the optical signal. If the signal quality does not improve, the light source drive intensity is gradually increased according to a predetermined rule. All parameter adjustments adopt a gradual change strategy to avoid system instability caused by sudden changes.

[0023] The system has set up a hierarchical safety protection mechanism. When the pressure value exceeds 40kPa for 5 seconds continuously, or the PPG signal quality fails to meet the standard for 3 consecutive times (PPG signal failure may indicate blood flow restriction), the basic protection layer is triggered; if it does not recover within 15 seconds, it will be upgraded to the advanced protection layer. The flow chart is as follows Figure 5 As shown: Basic protection layer: When it is detected that the pressure parameters deviate from the safe working range, the forced voltage reduction program is immediately triggered and the maximum output power of the light source is limited; this protection layer continuously monitors the parameter recovery status and automatically releases the protection state when it detects that the indicators return to the normal range; Advanced Protection Layer: When basic protection fails to effectively correct an abnormal state or detects a signal failure, the system initiates deep protection, logging and archiving all parameter anomalies while adjusting the pressure to the minimum level required to maintain basic detection functions. If the abnormal state persists for longer than a preset judgment period, a safe sleep mode is activated while maintaining power to key modules. After the operating environment returns to normal, the system performs an automatic calibration process and gradually transitions back to standard detection mode. The entire controller adopts a dual-monitoring architecture, with the pressure sensing channel and optical detection module operating in parallel. The controller coordinates the operating status of each subsystem. The transition thresholds for each stage can be flexibly configured according to the needs of different application scenarios. Through this design, the system achieves coordinated optimization of pressure control and optical detection, ensuring measurement reliability while also taking into account operational safety. In the specific implementation of the present invention, full population adaptation and environmental self-adaptation are achieved through the following methods: (1) Crowd adaptation control strategy: General population mode: adopts standard pressure-light intensity adjustment to achieve dual-parameter linear compensation; Child mode: coordinated reduction of pressure and light intensity; Elderly mode: uses progressive pressure loading and stable time adjustment; Hypertension model: establish dynamic safety monitoring intervals; High-risk population mode: triggering the pressure-light intensity linkage compensation mechanism; (2) Special scenario control strategy Long-term monitoring mode: Adopt the coordinated control of periodic pressure release and light intensity compensation; Environmental adaptation mode: Compensate for the deformation effect of materials through the dual-channel feedback of pressure-light intensity; The force actuator can also use other small driving devices, such as gear sets, micro motors or shape memory alloy springs; Those skilled in the art should understand that the specific implementation methods of the above-mentioned parts can be adjusted and combined according to actual needs, including the type of light source, the method of pressure regulation, the arrangement of sensors, etc.; the control parameters of the system, such as the magnitude of pressure, the adjustment speed, the signal compensation method, etc., can also be optimized according to actual usage requirements; The closed-loop control method of the present invention is also applicable to other PPG device forms (such as wristband type, patch type, ear clip type, forehead wear, etc.), only need to adjust the mechanical structure of the force actuator according to the physical characteristics of the device to be measured, without changing the pressure-light intensity coordinated control logic. Embodiment 2

[0024] In another embodiment of the present invention, the light source assembly 2 and the photodetector 3 are located on the same side of the object to be measured, as shown in the schematic diagram Figure 6 shown, and the rest will not be elaborated. Embodiment 3

[0025] In another embodiment of the present invention, the pressure sensor 4 is placed on the inner layer of the conduction assembly 9, as shown in the schematic diagram Figure 7 shown. The pressure sensor 4 adopts a flexible transparent film type sensor, and its flexible characteristics are compatible with the characteristics of the inner layer, and the transparency reduces the interference with optical detection. The rest will not be elaborated. Embodiment 4

[0026] In another embodiment of the present invention, the force actuator 4 adopts a dielectric elastomer material, such as a carbon nanotube (CNT) / silicone rubber composite material; the flexible inner layer of the conduction assembly 9 used also adopts a flexible silicone rubber material to be integrally fused with the carbon nanotube (CNT) / silicone rubber composite material. This material can undergo controllable deformation under the action of an electric field to adapt to the skin surface. As shown in the schematic diagram Figure 8 shown, and the rest will not be elaborated. Embodiment 5

[0027] In another embodiment of the present invention, the force actuator 4 is arranged on the rigid outer layer and is located below the object to be measured; the force actuator 4 adopts a micro pneumatic cavity array, and the overall thickness is changed by adjusting the internal air pressure, so as to achieve the purpose of adjusting the contact pressure. The light source assembly 2 and the photodetector 3 are located on the same side of the object to be measured. As shown in the schematic diagram Figure 9 shown, and the rest will not be elaborated.

Claims

1. An autonomous regulation type PPG detection device, comprising a mechanical execution module, an optical detection module, a pressure sensing module and a controller; characterized in that: The mechanical execution module includes a force actuator and a conduction component; The conduction component is a three-layer rigid-flexible gradient structure, including an outer layer, a middle layer and an inner layer; the inner wall of the outer layer is a black structure, the inner wall of the outer layer is connected to the outer wall of the middle layer, the inner wall of the middle layer is connected to the outer wall of the inner layer, and a cavity is provided inside the inner layer for accommodating the object to be measured; the outer layer, the middle layer and the inner layer form a mechanical conduction path pointing to the object to be measured; the inner layer also serves as an optical coupling interface; the stiffness of the conduction component decreases along the contact direction of the object to be measured; the outer layer is a rigid frame, the middle layer is an elastic layer, and the inner layer is a flexible layer; the inner wall of the rigid outer layer adopts a black light-absorbing structure to form a black inner wall, and a cavity is provided inside for supporting the light source component, the photoelectric receiver and the force actuator; the middle layer adopts a light-transmitting elastic buffer material, and its elastic modulus is between that of the outer layer and the inner layer; the inner layer adopts a light-transmitting and adhesive high-flexible material to form a contact interface with the object to be measured, which is both the mechanical conduction terminal and the optical coupling interface; The force actuator is fixed to the outer layer or the inner layer of the conduction component; the conduction component receives the force from the force actuator and transmits the pressure to the object to be measured; The optical detection module includes a light source component and a photoelectric receiver. The PPG detection device adopts a transmissive or reflective structure. When it is a transmissive structure, the light source component and the photoelectric receiver are located on both sides of the object to be measured, that is, the light source component is located on the outer layer of the conduction component, and the photoelectric receiver is located on the outer layer of the conduction component. The light source component emits light waves to the object to be measured, and the photoelectric receiver receives the optical signal from the object to be measured; when it is a reflective structure, the light source component and the photoelectric receiver are located on the same side of the object to be measured, that is, the light source component and the photoelectric receiver are both located on the outer layer of the conduction component; The pressure sensing module includes at least one pressure sensor, which is arranged on the conduction component in a flat or embedded manner. Each pressure sensor is connected to the controller, and the pressure sensing module transmits data to the controller as an adjustment reference; The controller includes a signal acquisition module, a processing module, and an output module; the signal acquisition module includes a pressure signal acquisition channel and an optical signal acquisition channel. The pressure signal acquisition channel includes a first front-end conditioning circuit connected to the output end of a pressure sensor and a first analog-to-digital conversion circuit connected thereto. The optical signal acquisition channel includes a second front-end conditioning circuit connected to the output end of a photoelectric receiver and a second analog-to-digital conversion circuit connected thereto. The two channels independently receive and preprocess the signals of the pressure sensor and the optical detector, and convert them into digital signals; the processing module receives the digital signals from the signal acquisition module and executes the pressure-light intensity collaborative control method. The output end of the processing module is respectively connected to the input ends of a force actuator and a light source assembly. The processing module receives the pressure sensing data of the pressure sensor, calculates and generates a pressure adjustment instruction and outputs it to the output module. The processing module receives the PPG optical data, calculates and generates a corresponding light intensity compensation instruction and outputs it to the output module; the output module converts the instructions of the processing module into hardware-executable instructions, drives the collaborative action of the force actuator, the outer layer, the middle layer, the outer layer of the conduction assembly, and the light source assembly, and adjusts to / maintains the optimal detection state.

2. The self-regulating PPG detection device according to claim 1, characterized in that The force actuator is located in the mechanical transmission path and is a physical component that adjusts the contact pressure by changing at least one of the geometric configuration, spatial position, or material properties of the structure; specifically, a scissor-type telescopic mechanism, a dielectric elastomer material, or a micro-pneumatic cavity array is used to dynamically adjust the contact pressure by changing the spatial position or shape of the conduction assembly.

3. The self-regulating PPG detection device according to claim 1, wherein The light source assembly includes at least one LED light source, integrating a multi-wavelength LED light source array. The light source uses green light or an infrared wavelength. The photoelectric detector includes a silicon photodiode or a similar photosensitive element.

4. A control method for an autonomous regulation type PPG detection device as described in claim 1, characterized in that The specific steps are as follows: After the PPG detection device is started, first perform initial pressure calibration and establish basic light intensity parameters. Subsequently, during the detection process, the contact pressure change and the optical signal quality are monitored in real time. When the contact pressure detected by the pressure sensing module deviates from the preset range, the controller comprehensively judges the pressure state and the PPG optical signal characteristics, generates the optimal adjustment parameters, and transmits the instructions to the force actuator of the mechanical execution module; The force actuator responds to the drive, adjusts the contact pressure between the PPG detection device and the object to be measured by deformation, and cooperates with the viscous characteristics of the inner layer of the conduction assembly to maintain the best fitting state; the adjustment process of the conduction assembly adopts a progressive method, mainly based on pressure adjustment first. When the pressure enters the stable range, then fine-tune the light intensity to optimize the signal quality. Evaluate the improvement of the PPG signal after each adjustment until the stable detection state is reached; This active adjustment closed-loop control method can sense the change trend of the contact pressure in real time, quickly respond and maintain the best contact state, and can effectively solve the signal quality problems caused by individual differences, changes in motion state, and environmental factors.

5. The control method of the self-regulating PPG detection device according to claim 4, wherein The control method further includes an exception handling mechanism. When continuous abnormal pressure is detected, a hierarchical protection program is started: in the initial stage, priority is given to gradually reducing the pressure to restore the safe contact state; when the pressure adjustment cannot improve the signal quality, it automatically switches to the light intensity compensation mode to dynamically adjust the light source output power; if the abnormal state persists, the safe sleep mechanism is triggered. The entire process maintains the coordinated operation of pressure regulation and light compensation to ensure use safety and measurement effectiveness.

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