A knee joint three-point pressurization control method, system and knee joint protector

Abstract

The application discloses a knee joint three-point pressure control method, comprising the following steps: reading a pre-stored knee joint angle-target pressure mapping curve, the mapping curve containing the corresponding relationship between the flexion angle and a plurality of target point target pressure values; acquiring the current knee joint flexion angle value; querying the mapping curve according to the flexion angle value to obtain the first target pressure value corresponding to the tibial tuberosity target point, the second target pressure value corresponding to the patellar tip target point and the third target pressure value corresponding to the quadriceps tendon target point; acquiring the current pressure feedback value corresponding to the tibial tuberosity target point, the patellar tip target point and the quadriceps tendon target point respectively, and adopting a PID control algorithm to calculate the pressure control amount of each target point based on the target pressure value and the corresponding current pressure feedback value, and generating a digital control instruction output for adjusting the pressure of each target point respectively. The application realizes the pressure regulation and control of the three key target points of the knee joint, namely the tibial tuberosity, the patellar tip and the quadriceps tendon.

Description

Technical Field

[0001] This invention relates to the field of pressure control technology, specifically to a three-point pressure control method, system, and knee brace for the knee joint. Background Technology

[0002] With the increasing awareness of fitness among the general public and the continuous improvement of competitive sports, the number of people participating in sports is expanding, and the need for protection against joint sports injuries is becoming more and more urgent. As one of the most complex and weight-bearing joints in the human body, the knee joint is extremely prone to ligament damage and patellofemoral pain syndrome in sports scenarios such as running, jumping, and sudden stops and changes of direction due to excessive impact load or unstable movement posture. After a knee injury, a sharp pain and weakness in the leg may occur when straightening the knee joint at the moment of squatting, jumping, or climbing stairs.

[0003] Canadian invention patent CA3047880A1 proposes an active compression suit solution based on microfluidics and microfluidics technologies. This solution utilizes these technologies to achieve an active compression suit that is completely unrestrained, ultra-lightweight, extremely form-fitting, and aesthetically pleasing, providing some protection and adaptability for muscles and joints during exercise. However, this solution still has the following shortcomings: First, its pressurization method is overall pressurization, lacking precise differentiation of different stress areas. Since the knee joint force sensor Golgi apparatus is mainly concentrated at the tendon attachment point, overall pressurization cannot accurately adapt to the mechanical characteristics of the knee joint during extension movements, thus failing to effectively achieve assistance during knee extension and effort-saving effects for the quadriceps. Second, its pressure control strategy is based on the pressure sensor chip built into the airbag, relying on the equivalent fluid resistance principle of the microfluidics and microfluidics systems. That is, when the air pressure inside the airbag reaches a single peak, it switches to the next airbag for continuous pressurization, and this cycle repeats. This method does not establish a quantitative mapping relationship between the knee flexion angle and the target pressure at each target point, which limits the accuracy of pressure regulation and response speed.

[0004] Chinese invention patent CN117563209A proposes an air pump control method, system, and inflatable joint brace. This solution, through the setup of an air pump device, multiple micro-adjustable airbags, and a sensing module, obtains the corresponding pressure adjustment threshold based on the user's selected exercise scenario. It then dynamically adjusts the airbag inflation pressure by comparing the perceived pressure with the pressure adjustment threshold, achieving a certain degree of adjustability in the brace's support stiffness and adaptability to different exercise scenarios. However, this technical solution still has the following shortcomings: First, its pressure adjustment is based on a comparison of overall perceived pressure with a preset threshold, lacking a refined distinction of the force differences at different anatomical locations of the knee joint, making it difficult to achieve multi-point precise control of the local load distribution of the knee joint; second, its control strategy relies on scenario matching and threshold comparison as its core logic, failing to establish a quantitative mapping relationship between the knee flexion angle and the target pressure at each target point, thus limiting adjustment accuracy and response speed; third, its airbag structure is an integral or array-type micro-airbag, without differentiated design for the biomechanical characteristics of different soft tissue target points of the knee joint, requiring improvement in the targeting and effectiveness of local support.

[0005] Currently, the field of knee braces lacks a technology that precisely controls the pressure at three key target points—the tibial tuberosity, the patellar apex, and the quadriceps tendon—to achieve effortless assistance during squatting and standing. Addressing this technological gap, Dr. Fu, specializing in sports biomechanics at the Education University of Hong Kong, has developed this three-point pressure control method for the knee joint. This method establishes a precise mapping curve between the knee flexion angle and the target pressure at key points such as the tibial tuberosity, patellar apex, and quadriceps tendon. Combined with real-time monitoring of the flexion angle using an inertial measurement unit, a PID control algorithm is employed to independently control the closed-loop pressure of the airbags corresponding to each target point. This aims to achieve precise assistance for knee extension movements and effortless muscle control, overcoming the shortcomings of existing technologies in quantitative angle-pressure mapping and multi-point independent control. Summary of the Invention

[0006] To overcome the above-mentioned technical defects, the present invention provides a method, system and knee joint brace for three-point pressure control of the knee joint.

[0007] To solve the above problems, the present invention is implemented according to the following technical solution:

[0008] In a first aspect, the present invention provides a three-point compression control method for the knee joint, comprising:

[0009] S1: Read the pre-stored knee joint angle-target pressure mapping curve, which includes the correspondence between flexion angle and target pressure values ​​at multiple target points;

[0010] S2: Obtain the current knee flexion angle value input from the outside;

[0011] S3: Based on the flexion angle value, query the mapping curve to obtain the first target pressure value corresponding to the tibial tuberosity target point, the second target pressure value corresponding to the patellar tip target point, and the third target pressure value corresponding to the quadriceps tendon target point;

[0012] S4: Obtain the current pressure feedback values ​​corresponding to the tibial tuberosity target point, patellar tip target point and quadriceps tendon target point respectively from the external input, and use the PID control algorithm to calculate the pressure control quantity of each target point based on each target pressure value and the corresponding current pressure feedback value, and generate digital control command outputs for adjusting the pressure of each target point respectively.

[0013] In conjunction with the first aspect, the present invention provides a first specific implementation of the first aspect, specifically, when the knee joint is in the extended position at 0°, the target pressure value of each target point is maintained at a preset baseline pressure value;

[0014] As the knee flexion angle increases, the target pressure values ​​at each target point increase non-linearly.

[0015] When the knee flexion angle enters the preset functional angle range, the target pressure value of each target point reaches the preset peak value and is maintained.

[0016] In conjunction with the first aspect, the present invention provides a second specific embodiment of the first aspect, which specifically includes:

[0017] S5: Acquire the electromyographic signal of the quadriceps femoris muscle, and extract features from the electromyographic signal to obtain the root mean square value of electromyography and muscle contribution rate features of the rectus femoris, medial head of the femoris, and lateral head of the femoris.

[0018] If the electromyographic signal meets the preset high-efficiency mode conditions, then the target pressure values ​​corresponding to the current flexion angle are maintained.

[0019] If the electromyographic signal does not meet the preset high-efficiency mode conditions, the target pressure values ​​corresponding to the current flexion angle in the mapping curve are finely adjusted to achieve personalized pressure parameter optimization based on physiological feedback.

[0020] In conjunction with the first aspect, the present invention provides a third specific implementation of the first aspect, specifically, the fine-tuning of the target pressure values ​​corresponding to the current angle in the mapping curve includes:

[0021] Based on the root mean square values ​​of electromyography (EMG) and muscle contribution rates of the rectus femoris, medial head of the femoral head, and lateral head of the femoral head, the deviation from the reference EMG characteristics in the preset high-efficiency contraction mode is calculated to obtain the activation deviation of each muscle.

[0022] Based on the activation deviation and the preset adjustment gain coefficient, pressure adjustment increments corresponding to the tibial tuberosity target point, patellar tip target point and quadriceps tendon target point are generated respectively.

[0023] Each of the pressure adjustment increments is superimposed onto the corresponding target pressure value in the mapping curve at the current buckling angle to update the mapping curve.

[0024] In conjunction with the first aspect, the present invention provides a fourth embodiment of the first aspect, which specifically further includes:

[0025] S6: Obtain contact pressure distribution data within the pressure application area corresponding to each target point;

[0026] Calculate the pressure uniformity index for each pressure application area based on the contact pressure distribution data;

[0027] If the pressure uniformity index of any pressure application area is lower than the preset uniformity threshold, the target pressure distribution of different sub-regions within that area is adjusted, and / or the current target pressure value of that area is compensated and adjusted to improve local contact uniformity while maintaining the preset total pressurization effect.

[0028] In conjunction with the first aspect, the present invention provides a fifth specific implementation of the first aspect, specifically, the preset high-efficiency mode conditions include:

[0029] The root mean square values ​​of electromyography of the rectus femoris, medial head of the femoral head, and lateral head of the femoral head are all within their respective preset target activation ranges; and the ratio of the muscle contribution rates of the medial head of the femoral head to the lateral head of the femoral head is within a preset balance range.

[0030] If any condition is not met, the electromyographic signal is determined to not meet the high-efficiency mode condition.

[0031] Secondly, the present invention also provides a three-point compression control system for the knee joint, including a processor and a memory, wherein the memory stores a computer program, and the processor executes the computer program to implement the following modules:

[0032] The mapping curve reading module is used to read the pre-stored knee joint angle-target pressure mapping curve, which contains the correspondence between the flexion angle and the target pressure values ​​of multiple target points;

[0033] Angle acquisition module, used to obtain the current knee flexion angle value;

[0034] The target pressure query module is used to query the mapping curve based on the flexion angle value to obtain the first target pressure value corresponding to the tibial tuberosity target point, the second target pressure value corresponding to the patellar tip target point, and the third target pressure value corresponding to the quadriceps tendon target point.

[0035] The pressure control module is used to acquire the current pressure feedback values ​​corresponding to the tibial tuberosity target point, patellar tip target point and quadriceps tendon target point respectively, and to use a PID control algorithm to calculate the pressure control quantity of each target point based on each target pressure value and the corresponding current pressure feedback value, and generate digital control command outputs for adjusting the pressure of each target point respectively.

[0036] Thirdly, the present invention also provides a knee brace, comprising:

[0037] The main body of the protective gear is used to wrap around and fix it to the outside of the knee joint;

[0038] A six-axis inertial measurement unit is mounted on the main body of the protective gear and is used to collect the bending angle of the knee joint.

[0039] The first airbag, the second airbag, and the third airbag are respectively located on the inner side of the main body of the protective gear at three target points corresponding to the tibial tuberosity, the patellar tip, and the quadriceps tendon.

[0040] A miniature air pump and a miniature solenoid valve are fixed to the main body of the protective gear and connected to each airbag via air ducts.

[0041] Several pressure sensors are respectively installed in the air path of each airbag to detect the internal pressure of each airbag;

[0042] A microcontroller is fixed to the main body of the protective gear. The microcontroller is electrically connected to a six-axis inertial measurement unit, a micro air pump, a micro solenoid valve, and a pressure sensor. The microcontroller has a built-in nonlinear knee joint angle-target pressure mapping curve. Based on the real-time angle collected by the six-axis inertial measurement unit, the microcontroller queries the mapping curve and independently controls the pressure of the three airbags to reach the target pressure value corresponding to the real-time angle.

[0043] In conjunction with the third aspect, the present invention provides a second specific implementation of the third aspect. Specifically, the protective gear body is further provided with a power module and a status indicator light. The status indicator light is electrically connected to the microcontroller and is used to indicate the working status and power status of the device.

[0044] Compared with the prior art, the beneficial effects of the present invention are:

[0045] This invention targets three key biomechanical points: the tibial tuberosity, the patellar apex, and the quadriceps tendon. It establishes independent airbags and target pressure control channels for each point. Through multi-point independent closed-loop control, precise pressure can be applied based on the differences in soft tissue morphology and load-bearing capacity at each target point, effectively improving the local load distribution of the knee joint and avoiding insufficient support or excessive compression caused by overall pressure adapting to local conditions.

[0046] This invention employs a PID control algorithm to perform real-time closed-loop adjustment of the actual pressure of each airbag. The deviation between the target pressure value and the actual feedback value is used as input, and through the synergistic action of proportional, integral, and derivative components, inflation / deflation control commands are generated. This approach effectively suppresses air pressure fluctuations caused by muscle contraction or external impact during exercise, ensuring that the actual pressure at each target point quickly converges to the target value and remains stable. This significantly improves the protective reliability and wearing comfort of protective gear in dynamic, high-load exercise scenarios. Attached Figure Description

[0047] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings, wherein:

[0048] Figure 1 This is a flowchart of a three-point pressure control method for the knee joint according to the present invention.

[0049] Figure 2 This is a schematic diagram of the structure of a knee brace according to the present invention. Figure 1 .

[0050] Figure 3 This is a schematic diagram of the structure of a knee brace according to the present invention. Figure 2 .

[0051] In the diagram: 100 - main body of protective gear; 101 - first airbag; 102 - second airbag; 103 - third airbag. Detailed Implementation

[0052] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0053] It should be noted that when a component is said to be "fixed to" another component, it can be directly attached to the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0054] like Figures 1-2 As shown, this invention relates to a three-point pressure control method, system, and knee brace for the knee joint.

[0055] Example 1

[0056] According to an embodiment of the present invention, an embodiment of an air pump control method is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a system such as a handheld terminal. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0057] Please see Figure 1 , Figure 1 This is a flowchart of a three-point compression control method for the knee joint according to an embodiment of the present invention. The method includes the following steps:

[0058] S1: Read the pre-stored knee joint angle-target pressure mapping curve;

[0059] Specifically, the knee joint angle-target pressure mapping curve is pre-stored in the storage module. This mapping curve is obtained by fitting a large amount of sports biomechanics experimental data, establishing a quantitative correspondence between the knee joint flexion angle and the target pressure values ​​of the tibial tuberosity target point, patellar tip target point, and quadriceps tendon target point. In an optional scheme, this mapping curve can be used to create multiple sets of curves for different movement modes (such as jogging, squatting, jumping, etc.), and can be called up according to the movement mode selected by the user.

[0060] Furthermore, the microcontroller pre-stores the mapping relationship between the knee joint angle and the target pressure value at each target point, and the mapping relationship is configured to be a piecewise nonlinear distribution based on the knee joint bending angle.

[0061] Specifically:

[0062] (1) In the knee extension position, i.e., within the angle range of 0° to 10°, the target pressure value of each target point is maintained at the preset base pressure value. The base pressure value ranges from 5 to 10 kPa, which is used to provide basic fit support and avoid slippage of the protective gear body at the knee joint caused by the complete depressurization of the airbag;

[0063] (2) When the knee flexion angle increases from the straight position, the target pressure value of each target point increases non-linearly with the increase of the angle, so as to adapt to the physiological characteristics of increased soft tissue tension and increased joint stability requirements during knee flexion.

[0064] (3) When the knee flexion angle reaches the preset functional angle threshold, the target pressure value of each target point reaches the preset peak value and is maintained. The preset peak value is preset according to the application scenario of the protective gear, and is not lower than the target pressure value at any angle in step (2).

[0065] Preferably, the preset functional angle threshold can be calibrated according to different sports scenarios. As an example, and not a limitation: in walking or jogging scenarios, the functional angle threshold is set to 11°~30°; in climbing stairs or jumping scenarios, the functional angle threshold is set to 31°~60°; in squatting scenarios, the functional angle threshold is set to greater than 60°. Those skilled in the art will understand that the above angle range can be adaptively adjusted according to the joint mobility and exercise intensity of the specific user.

[0066] S2: Get the current knee flexion angle;

[0067] Specifically, a six-axis inertial measurement unit is fixed inside an electrical control box above the knee joint of the brace to detect the relative angle changes between the tibia and femur in real time.

[0068] S3: Based on the flexion angle value, query the mapping curve to obtain the first target pressure value corresponding to the tibial tuberosity target point, the second target pressure value corresponding to the patellar tip target point, and the third target pressure value corresponding to the quadriceps tendon target point;

[0069] Specifically, using the current flexion angle as a query index, target pressure values ​​corresponding to three anatomical target points are extracted from the mapping curve through linear interpolation or nearest neighbor interpolation. The tibial tuberosity target point mainly bears the quadriceps femoris pull transmitted by the patellar tendon; the patellar apex target point reflects the contact stress between the patella and the femoral synovial passage; and the quadriceps femoris tendon target point reflects the active contraction tension of the proximal muscle group. The target pressure values ​​of the three target points may differ at the same flexion angle to meet the biomechanical needs of each local tissue.

[0070] S4: Obtain the current pressure feedback values ​​corresponding to the tibial tuberosity target point, patellar tip target point and quadriceps tendon target point respectively, and use PID control algorithm to calculate the pressure control quantity of each target point based on each target pressure value and the corresponding current pressure feedback value, and generate digital control command output for adjusting the pressure of each target point respectively.

[0071] Specifically, a pressure sensor is installed in each airbag to monitor the current actual pressure in real time. That is, the pressure of each airbag is detected simultaneously to obtain the pressure of the target point of each airbag at the current moment. The deviation between the target pressure and the actual pressure is used as input, and after calculation, a pulse width modulation signal is output to drive the air pump or the exhaust valve to adjust the inflation rate or deflation rate.

[0072] S5: Acquire the electromyographic signal of the quadriceps femoris and extract features from the electromyographic signal to obtain the root mean square value of the electromyography of the rectus femoris, the medial head of the femoral head, and the lateral head of the femoral head, as well as the muscle contribution rate characteristics; if the electromyographic signal meets the preset high-efficiency mode conditions, maintain the target pressure values ​​corresponding to the current flexion angle; if the electromyographic signal does not meet the preset high-efficiency mode conditions, fine-tune the target pressure values ​​corresponding to the current flexion angle in the mapping curve to achieve personalized pressure parameter optimization based on physiological feedback.

[0073] Specifically, the electromyographic sensing electrodes are attached to the muscle bellies of the rectus femoris, vastus medialis, and vastus lateralis, and surface electromyographic signals are acquired using a differential method. The raw electromyographic signals are sequentially subjected to bandpass filtering, full-wave rectification, and smoothing from 20 to 450 Hz, and the root mean square (RMS) value is extracted. Using the RMS value of each muscle during maximum voluntary isometric contraction as a reference, the measured RMS value is converted into a normalized activation level (%MVC), and the contribution rate of each muscle to the overall activation of the quadriceps femoris is calculated accordingly. The conditions for the high-efficiency mode are: the activation levels of the rectus femoris, vastus medialis, and vastus lateralis all fall within their respective preset target activation ranges, and when performing squatting movements at knee flexion angles of 30°, 60°, and 90°, the overall RMS value (or overall activation level) of the quadriceps femoris is significantly lower than when not wearing a knee brace or wearing other existing pure textile knee braces, thus demonstrating that the method of this invention achieves an assistive effect. If any condition is not met, the system is deemed not to be in high-efficiency mode, indicating that the current pressure application is not providing significant assistance and requires fine-tuning of the pressure parameters. The theoretical basis for these conditions is that the knee joint experiences different loads at different flexion angles. The deeper the squat, the greater the joint load and the required assistance, thus necessitating a greater degree of pressure. For example, the knee joint load during large-amplitude movements such as deep squats and sudden stops is approximately 8 times the body weight; during activities like going down stairs and running, it is approximately 5-8 times the body weight; during brisk walking and climbing stairs, it is approximately 3-6 times the body weight; and during slow walking and standing, it is approximately 1-3 times the body weight.

[0074] Furthermore, the fine-tuning of the target pressure values ​​corresponding to the current angle in the mapping curve specifically includes: calculating the deviation between the root mean square electromyographic values ​​and muscle contribution rates of the rectus femoris, medial head, and lateral head of the femoral head and a preset reference electromyographic characteristic under a high-efficiency contraction mode to obtain the activation deviation of each muscle; generating pressure adjustment increments corresponding to the tibial tuberosity target point, patellar apex target point, and quadriceps tendon target point respectively, based on the activation deviation and a preset adjustment gain coefficient; and superimposing each pressure adjustment increment onto the corresponding target pressure value in the mapping curve at the current flexion angle to update the mapping curve. In an optional embodiment, the adjustment gain coefficient can be set according to the physiological cross-sectional area and lever arm length of the muscle to ensure the safety and effectiveness of incremental adjustment.

[0075] S6: Obtain contact pressure distribution data within the pressure application area corresponding to each target point;

[0076] Calculate the pressure uniformity index for each pressure application area based on the contact pressure distribution data;

[0077] If the pressure uniformity index of any pressure application area is lower than the preset uniformity threshold, the target pressure distribution of different sub-regions within that area is adjusted, and / or the current target pressure value of that area is compensated and adjusted to improve local contact uniformity while maintaining the preset total pressurization effect.

[0078] Specifically, the multi-point pressure sensor array is distributed at the interface between each airbag and the skin, and consists of multiple piezoresistive or capacitive sensing units, which can acquire the two-dimensional pressure distribution within the airbag coverage area. The pressure uniformity index is defined as the ratio of the standard deviation to the average value of the pressure distribution within the contact surface, or it can be characterized by the ratio of peak pressure to average pressure. When the index is lower than the uniformity threshold (e.g., less than 0.7), it indicates the existence of local pressure concentration or gap areas, which can easily lead to skin discomfort or uneven support. In an optional scheme, if the airbag has multiple independently controllable sub-chambers, the uniformity is improved by adjusting the target pressure distribution of each sub-chamber; if the airbag is a single-chamber structure, the current overall target pressure value is slightly compensated and adjusted, and iterative optimization is performed in combination with real-time distribution feedback until the uniformity index recovers to above the threshold.

[0079] Example 2

[0080] A three-point knee joint compression control system includes a processor and a memory. The memory stores a computer program, and the processor, when executing the computer program, implements the following modules: a mapping curve reading module, used to read a pre-stored knee joint angle-target pressure mapping curve, the mapping curve containing the correspondence between flexion angle and target pressure values ​​at multiple target points; an angle acquisition module, used to acquire the current knee joint flexion angle value; a target pressure query module, used to query the mapping curve based on the flexion angle value to obtain a first target pressure value corresponding to the tibial tuberosity target point, a second target pressure value corresponding to the patellar apex target point, and a third target pressure value corresponding to the quadriceps tendon target point; and a pressure control module, used to acquire the current pressure feedback values ​​corresponding to the tibial tuberosity target point, patellar apex target point, and quadriceps tendon target point respectively, and use a PID control algorithm to calculate the pressure control quantity of each target point based on each target pressure value and the corresponding current pressure feedback value, generating digital control command outputs for adjusting the pressure of each target point respectively.

[0081] Specifically, through the coordinated operation of the mapping curve reading module, target pressure query module, and pressure control module, independent target pressure query channels and PID closed-loop control channels are set for three key biomechanical target points: the tibial tuberosity, the patellar apex, and the quadriceps tendon. The actual pressure of each airbag can independently and accurately converge to its corresponding target value, realizing a technological leap from the overall coarse adjustment of air pressure in knee braces to anatomical target pressure application. This effectively improves the local load distribution of the knee joint and avoids problems such as insufficient support or excessive pressure on soft tissues caused by the overall pressure not adapting to the differences in local anatomical structures.

[0082] Example 3

[0083] A knee brace includes a brace body 100 for wrapping around and fixing to the outside of the knee joint.

[0084] Specifically, the main body 100 of the protective gear has a cylindrical or sleeve-like structure, employing a design that combines a flexible fabric matrix with elastic straps. It can be fixed to the lower thigh and upper calf using Velcro or buckle straps to cover the area around the knee joint. The material of the main body 100 of the protective gear includes, but is not limited to, nylon elastic fabric, spandex blended fabric, or ACF biomimetic cartilage metamaterial. Preferably, it is a composite structure of ACF material and breathable Lycra fabric, wherein the ACF material layer is located in the area corresponding to the pressure of the target point, providing extreme cushioning protection.

[0085] A six-axis inertial measurement unit is fixedly installed on the main body 100 of the protective gear. The six-axis inertial measurement unit is used to collect the bending angle of the knee joint in real time.

[0086] In one alternative, two six-axis inertial measurement units can be installed on the thigh and lower leg sections of the protective gear body 100, respectively. The knee flexion angle is obtained by calculating the relative attitude angle difference between the two sections, thereby improving the measurement accuracy.

[0087] The first airbag 101, the second airbag 102, and the third airbag 103 are respectively located on the inner side of the protective gear body 100 at three target points corresponding to the tibial tuberosity, the patellar tip, and the quadriceps tendon.

[0088] Specifically, the first airbag 101 corresponds to the tibial tuberosity target point and is positioned on the inner anteroinferior side of the brace body 100, directly facing the tibial tuberosity region when worn; the second airbag 102 corresponds to the patellar apex target point and is positioned on the inner anterior side of the brace body 100, directly facing the inferior pole region of the patella when worn; the third airbag 103 corresponds to the quadriceps tendon target point and is positioned on the inner anterosuperior side of the brace body 100, directly facing the quadriceps tendon attachment area at the upper edge of the patella when worn. Each airbag is independent and surrounds the knee joint, meaning each airbag has an arc-shaped or ring-shaped structure with a coverage width sufficient to encompass the peri-knee region corresponding to the anatomical location of the target point. Each airbag is made of latex tubing.

[0089] A miniature air pump and a miniature solenoid valve are fixed to the protective gear body 100 and connected to each airbag via air guide tubes. Specifically, the miniature air pump is installed on the outside of the protective gear body 100. The miniature solenoid valve is a three-way miniature solenoid valve, with one independent solenoid valve for each airbag, used to control the inflation and deflation of each airbag respectively. The air guide tube is a silicone tube, laid along the fabric interlayer of the protective gear body 100, with one end connected to the air inlet of the miniature air pump and the miniature solenoid valve, and the other end connected to the air inlet of each airbag.

[0090] Several pressure sensors are installed in the air path of each airbag to detect the internal pressure of each airbag.

[0091] Specifically, a miniature pressure sensor is installed on the air duct of each airbag or inside the airbag body. The pressure sensor adopts MEMS piezoresistive or capacitive pressure sensor with a range of 0~100 kPa and an accuracy of ±0.5% FS. It is used to collect the current actual pressure value of each airbag in real time and feed it back to the microcontroller.

[0092] The microcontroller is fixed on the protective gear body 100 and is electrically connected to the six-axis inertial measurement unit, the micro air pump, the micro solenoid valve and the air pressure sensor.

[0093] The microcontroller has a built-in nonlinear knee joint angle-target pressure mapping curve, and queries the mapping curve based on the real-time angle collected by the six-axis inertial measurement unit, and independently controls the pressure of the three airbags to reach the target pressure value corresponding to the real-time angle.

[0094] Specifically, the microcontroller employs a low-power embedded microprocessor with an ARM Cortex-M4 core, integrating an ADC acquisition interface, a PWM output interface, and a serial communication interface. The microcontroller's internal non-volatile memory stores a preset mapping curve data table. This curve is a non-linear function fitted through biomechanical experiments, defining the optimal support pressure values ​​for each of the three target points—the tibial tuberosity, patellar apex, and quadriceps tendon—within a flexion angle range of 0° to 90°. The microcontroller performs the following operations with a control cycle of at least 50 Hz: reading angle data from the six-axis inertial measurement unit → querying the mapping curve to obtain the three target pressure values ​​→ reading the current actual pressure values ​​from the three air pressure sensors → outputting a PWM signal after PID calculation to drive a micro-pump and a micro-solenoid valve, ensuring that the actual pressure of the three airbags independently and accurately converges to their respective target values. To verify the functionality of the above control scheme, an electromyography (EMG) comparative experiment was conducted. Three healthy adult male volunteers were selected, and three test conditions were used: wearing the protective gear of this invention, not wearing any protective gear, and wearing commercially available Mamba protective gear. During the experiment, electrodes from an electromyography (EMG) device were attached to the rectus femoris, vastus medialis, and vastus lateralis muscles of the volunteers. Volunteers were instructed to perform a single-leg squat with their left leg at a constant speed at three typical flexion angles of 30°, 60°, and 90°, with each angle repeated three times. The root mean square amplitude (RMS) of the EMG during the squatting motion and the peak EMG value after stabilization by PID closed-loop control were recorded. Repeated measures ANOVA was performed on the data from multiple participants using SPSS software. The results showed that all indicators were statistically significant. The experimental data are summarized in Table 1 in three-line table format.

[0095] Table 1

[0096]

[0097] Furthermore, the protective gear body 100 is also equipped with a power module and a status indicator light, which is electrically connected to the microcontroller and is used to indicate the working status and power status of the device.

[0098] Specifically, the power module includes a rechargeable lithium-ion battery and a charge / discharge management circuit, fixed in the battery compartment on the outside of the protective gear body 100. It provides a stable power supply to components such as the microcontroller, micro air pump, six-axis inertial measurement unit, and barometric pressure sensor. The status indicator lights include multi-color LEDs: solid green indicates normal operation, slow flashing green indicates standby, fast flashing red indicates low battery and the need for charging, and flashing blue indicates the system is performing mapping curve self-calibration or electromyography feedback adjustment. These status indicator lights allow users to intuitively understand the protective gear's working status, preventing support failure during movement due to insufficient power or system malfunctions, thus improving safety and convenience.

[0099] In actual exercise, as the knee flexion angle changes, the patellar tendon tension in the tibial tuberosity region, the patellofemoral joint contact force in the patellar apex region, and the muscle tension in the quadriceps tendon region each exhibit different changing patterns. This invention, through a microcontroller-embedded nonlinear mapping curve and independent air pressure control loop, allows the pressure of each airbag to independently track its optimal target value, contributing to improved accuracy of support control and biomechanical adaptability. Even if one airbag malfunctions, the other two airbags can continue to function, ensuring the basic support function of the protective gear is not lost, thus guaranteeing the system's fault tolerance and reliability.

[0100] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for controlling three-point pressure on the knee joint, characterized in that, The method is used to regulate pressure at three key target points of the knee joint—the tibial tuberosity, the patellar apex, and the quadriceps tendon—at different squatting angles, in order to activate knee joint force sensation and make squatting movements more effortless; the method includes: S1: Read the pre-stored knee joint angle-target pressure mapping curve, which includes the correspondence between flexion angle and target pressure values ​​at multiple target points; S2: Get the current knee flexion angle value; S3: Based on the flexion angle value, query the mapping curve to obtain the first target pressure value corresponding to the tibial tuberosity target point, the second target pressure value corresponding to the patellar tip target point, and the third target pressure value corresponding to the quadriceps tendon target point; S4: Obtain the current pressure feedback values ​​corresponding to the tibial tuberosity target point, patellar tip target point and quadriceps tendon target point respectively, and use PID control algorithm to calculate the pressure control quantity of each target point based on each target pressure value and the corresponding current pressure feedback value, and generate digital control command output for adjusting the pressure of each target point respectively.

2. The method for controlling three-point pressure on the knee joint according to claim 1, characterized in that, The mapping curve is configured as follows: With the knee extended at 0°, the target pressure value at each target point remains at the preset baseline pressure value. As the knee flexion angle increases, the target pressure values ​​at each target point increase non-linearly. When the knee flexion angle enters the preset functional angle range, the target pressure value of each target point reaches the preset peak value and is maintained.

3. The method for three-point pressure control of the knee joint according to claim 1, characterized in that, Also includes: S5: Acquire the electromyographic signal of the quadriceps femoris muscle, and extract features from the electromyographic signal to obtain the root mean square value of electromyography and muscle contribution rate features of the rectus femoris, medial head of the femoris, and lateral head of the femoris. If the electromyographic signal meets the preset high-efficiency mode conditions, then the target pressure values ​​corresponding to the current flexion angle are maintained. If the electromyographic signal does not meet the preset high-efficiency mode conditions, the target pressure values ​​corresponding to the current flexion angle in the mapping curve are finely adjusted to achieve personalized pressure parameter optimization based on physiological feedback.

4. The method for three-point pressure control of the knee joint according to claim 3, characterized in that, The fine-tuning of the target pressure values ​​corresponding to the current angle in the mapping curve specifically includes: Based on the root mean square values ​​of electromyography (EMG) and muscle contribution rates of the rectus femoris, medial head of the femoral head, and lateral head of the femoral head, the deviation from the reference EMG characteristics in the preset high-efficiency contraction mode is calculated to obtain the activation deviation of each muscle. Based on the activation deviation and the preset adjustment gain coefficient, pressure adjustment increments corresponding to the tibial tuberosity target point, patellar tip target point and quadriceps tendon target point are generated respectively. Each of the pressure adjustment increments is superimposed onto the corresponding target pressure value in the mapping curve at the current buckling angle to update the mapping curve.

5. A method for controlling three-point pressure on the knee joint according to any one of claims 1 to 4, characterized in that, Also includes: S6: Obtain contact pressure distribution data within the pressure application area corresponding to each target point; Calculate the pressure uniformity index for each pressure application area based on the contact pressure distribution data; If the pressure uniformity index of any pressure application area is lower than the preset uniformity threshold, the target pressure distribution of different sub-regions within that area is adjusted, and / or the current target pressure value of that area is compensated and adjusted to improve local contact uniformity while maintaining the preset total pressurization effect.

6. The method for three-point pressure control of the knee joint according to claim 3, characterized in that, The preset high-efficiency mode conditions include: The root mean square values ​​of electromyography of the rectus femoris, medial head of the femoral head, and lateral head of the femoral head are all within their respective preset target activation ranges; and the ratio of the muscle contribution rates of the medial head of the femoral head to the lateral head of the femoral head is within a preset balance range. If any condition is not met, the electromyographic signal is determined to not meet the high-efficiency mode condition.

7. A three-point compression control system for the knee joint, characterized in that, It includes a processor and a memory, wherein the memory stores a computer program, and the processor executes the computer program to implement the following modules: The mapping curve reading module is used to read the pre-stored knee joint angle-target pressure mapping curve, which contains the correspondence between the flexion angle and the target pressure values ​​of multiple target points; Angle acquisition module, used to obtain the current knee flexion angle value; The target pressure query module is used to query the mapping curve based on the flexion angle value to obtain the first target pressure value corresponding to the tibial tuberosity target point, the second target pressure value corresponding to the patellar tip target point, and the third target pressure value corresponding to the quadriceps tendon target point. The pressure control module is used to acquire the current pressure feedback values ​​corresponding to the tibial tuberosity target point, patellar tip target point and quadriceps tendon target point respectively, and to use a PID control algorithm to calculate the pressure control quantity of each target point based on each target pressure value and the corresponding current pressure feedback value, and generate digital control command outputs for adjusting the pressure of each target point respectively.

8. A knee brace, applied to the knee joint three-point compression control system of claim 7, characterized in that, include: The main body of the protective gear is used to wrap around and fix it to the outside of the knee joint; A six-axis inertial measurement unit is mounted on the main body of the protective gear and is used to collect the bending angle of the knee joint. The first airbag, the second airbag, and the third airbag are respectively positioned on the inner side of the protective gear body at three target points corresponding to the tibial tuberosity, the patellar tip, and the quadriceps tendon. A miniature air pump and a miniature solenoid valve are fixed to the main body of the protective gear and connected to each airbag via air ducts. Several pressure sensors are respectively installed in the air path of each airbag to detect the internal pressure of each airbag; A microcontroller is fixed to the main body of the protective gear. The microcontroller is electrically connected to a six-axis inertial measurement unit, a micro air pump, a micro solenoid valve, and a pressure sensor. The microcontroller has a built-in mapping curve and queries the mapping curve based on the real-time angle collected by the six-axis inertial measurement unit to control the pressure of the three airbags to reach the target pressure value corresponding to the real-time angle.

9. A knee brace according to claim 8, characterized in that, The protective gear body is also equipped with a power module and a status indicator light. The status indicator light is electrically connected to the microcontroller and is used to indicate the working status and power status of the device.

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