Lower extremity exoskeleton airbag control method
By analyzing gait information and controlling the inflation and deflation of the airbag assembly, the problem of poor rehabilitation effect of lower limb exoskeleton devices was solved, venous blood return and blood circulation were promoted, the risk of venous thrombosis was reduced, and the rehabilitation training effect was improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NANCHANG UNIV
- Filing Date
- 2022-12-29
- Publication Date
- 2026-05-29
Smart Images
Figure CN116270146B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of lower limb exoskeleton technology, and in particular to a method for controlling airbags in a lower limb exoskeleton. Background Technology
[0002] A lower limb exoskeleton is a power assist device worn on the user's body that helps the wearer perform functions such as protection, support, and walking assistance.
[0003] Lower limb muscle injuries are common in the elderly and those in high-intensity occupations. After a muscle injury, the patient cannot perform normal weight-bearing activities. Furthermore, patients who are bedridden for a long time cannot actively engage in rehabilitation training, which weakens the muscle elasticity that facilitates venous return and makes them more prone to venous thrombosis.
[0004] In existing technologies, general lower limb exoskeleton devices can help patients walk, thereby exercising their lower limbs, stimulating their motor nerves and muscles, and achieving the effect of rehabilitation training. However, due to the poor physical strength of this group of people, the exercise time is short, the training effect is limited, and they are still in a bedridden state most of the time, resulting in poor rehabilitation effects. Summary of the Invention
[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a lower limb exoskeleton airbag control method, which aims to solve the technical problem of poor rehabilitation effect in the prior art.
[0006] To achieve the above objectives, the present invention provides a method for controlling airbags in a lower limb exoskeleton, comprising the following steps:
[0007] Acquire the acceleration data of the feet in the X, Y, and Z directions to obtain the corresponding waveform output data;
[0008] Gait information is obtained by performing gait analysis on the waveform output data, wherein the gait information includes walking speed and walking cycle;
[0009] Knee joint angle data is acquired and combined with the gait information to obtain comprehensive gait information;
[0010] The movement state of the human body is determined based on the comprehensive gait information.
[0011] When the movement state is the bed rest braking state, the several airbag groups of the legs are controlled to inflate sequentially from the distal end to the proximal end until the air pressure in the airbag group reaches the preset range, and then the several airbag groups are controlled to deflate sequentially from the proximal end to the distal end.
[0012] Compared with existing technologies, the beneficial effects of this invention are as follows: By intelligently judging the human body's movement state through gait information, when the body is in a bed-restoring mode, several airbag groups in the legs are inflated sequentially from the distal to the proximal end until the air pressure within the airbag groups reaches a preset range. This achieves a wave-like inflation, expansion, and deflation of the limbs, with directionality, gradualness, and cumulative squeezing effect, promoting the return of stagnant venous blood and lymph, accelerating venous blood flow in the limbs, eliminating edema, and promoting blood circulation. Once the air pressure within the airbag groups reaches the preset range, the airbag groups are deflated sequentially from the proximal to the distal end, ensuring that the pressure at the distal end is higher than that at the proximal end, facilitating blood return. Simultaneously, the cyclic inflation and deflation of the airbags simulates a physical massage of the leg muscles, effectively increasing venous blood return, reducing the burden on the heart's return flow, and decreasing the possibility of leg venous valve abnormalities, thereby improving rehabilitation outcomes.
[0013] According to one aspect of the above technical solution, the step of determining the human body's motion state based on the comprehensive gait information specifically includes:
[0014] The walking speed is used to determine whether the human body is in a dynamic or static state.
[0015] Once the human body is determined to be in a static state, the motion state of the human body is determined based on the acceleration data and the angle data.
[0016] Once the motion state is determined to be dynamic, the motion state of the human body is determined based on the waveform output data, the walking cycle, the walking speed, and the acceleration data.
[0017] According to one aspect of the above technical solution, the step of determining the motion state of the human body based on the acceleration data and the angle data specifically includes:
[0018] When the magnitude of the acceleration data along the X-axis or Y-axis is within a first preset range, the motion state is determined to be a bed rest braking state.
[0019] When the magnitude of the acceleration data along the Z-axis is within the first preset range, the motion state is determined to be a standing state.
[0020] When the angle data is within the second preset range, the motion state is determined to be a sitting state.
[0021] According to one aspect of the above technical solution, the airbag group includes a first airbag group and a second airbag group respectively disposed on the front and back sides of the thigh, and a third airbag group and a fourth airbag group respectively disposed on the front and back sides of the calf. The first airbag group includes a first single-cavity airbag, a second single-cavity airbag and a third single-cavity airbag. The second airbag group includes a fourth single-cavity airbag, a fifth single-cavity airbag, a sixth single-cavity airbag and a seventh single-cavity airbag. The third airbag group includes an eighth single-cavity airbag and a ninth single-cavity airbag. The fourth airbag group includes a tenth single-cavity airbag and an eleventh single-cavity airbag.
[0022] When the movement state is the bed rest braking state, firstly, the third airbag group and the fourth airbag group of the lower leg are controlled to inflate several single-chamber airbags in a first preset order. Then, the first airbag group and the second airbag group of the thigh are controlled to inflate several single-chamber airbags in a second preset order. When the air pressure of all the single-chamber airbags reaches the preset value, the pressure is maintained for a preset time, and then all the single-chamber airbags are controlled to deflate simultaneously.
[0023] According to one aspect of the above technical solution, when the movement state is a standing mode, the second airbag group, the third airbag group and the fourth airbag group are controlled to maintain a low pressure and pressure holding state, and several single-chamber airbags of the first airbag group are controlled to inflate simultaneously, and then depressurize after reaching a preset value.
[0024] According to one aspect of the above technical solution, when the movement state is a sitting mode, the first airbag group and the seventh single-chamber airbag group are first controlled to inflate in a third preset order until the air pressure reaches the preset value. Then, the fourth airbag group is controlled to inflate in a fourth preset order until the preset value is reached. Finally, the first airbag group and the seventh single-chamber airbag group are controlled to deflate until the air pressure reaches the preset value.
[0025] According to one aspect of the above technical solution, the step of determining the human body's motion state based on the waveform output data, the walking cycle, the walking speed, and the acceleration data specifically includes:
[0026] When the walking cycle is within a third preset range, the movement state is determined to be a walking state;
[0027] When the path of the peak in the waveform output data is greater than the path of the peak behind it, the motion state is determined to be an upstairs state.
[0028] When the value of the acceleration data along the Z-axis is less than the first threshold, the motion state is determined to be a downstairs state.
[0029] According to one aspect of the above technical solution, when the movement state is walking, the first airbag group, the seventh single-chamber airbag, and the third airbag group are controlled to inflate simultaneously in a fifth preset order. When the pressure of the first airbag group, the seventh single-chamber airbag, and the third airbag group reaches a preset value, they begin to deflate. At this time, the fourth airbag group is controlled to inflate. When the pressure of the fourth airbag group reaches a preset value, it deflates, and the fourth single-chamber airbag, the fifth single-chamber airbag, and the sixth single-chamber airbag are controlled to inflate simultaneously.
[0030] According to one aspect of the above technical solution, when the movement state is the upstairs state, the first airbag group, the fifth single-chamber airbag, the seventh single-chamber airbag and the tenth single-chamber airbag at the leg in the supporting state are inflated and then deflated, and the seventh single-chamber airbag and the ninth single-chamber airbag at the leg in the swinging state are inflated and then deflated.
[0031] According to one aspect of the above technical solution, when the movement state is the downstairs state, the first airbag group and the ninth single-chamber airbag at the leg in the supporting state are controlled to inflate and then deflate, and the first airbag group, the seventh single-chamber airbag and the ninth single-chamber airbag at the leg in the swinging state are controlled to inflate and then deflate. Attached Figure Description
[0032] Figure 1 This is a flowchart of a lower limb exoskeleton airbag control method in one embodiment of the present invention;
[0033] Figure 2 This is a flowchart of a gait analysis algorithm in one embodiment of the present invention;
[0034] Figure 3 This is a flowchart of the airbag control process in one embodiment of the present invention;
[0035] Figure 4 This is a schematic diagram of the distribution of the airbag assembly in one embodiment of the present invention;
[0036] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation
[0037] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Several embodiments of the invention are illustrated in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
[0038] It should be noted that when a component is said to be "fixed to" another component, it can be directly on 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.
[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.
[0040] Please see Figure 1 The diagram shows a flowchart of a lower limb exoskeleton airbag control method according to an embodiment of the present invention, which includes the following steps:
[0041] Step S100: Obtain the acceleration data of the foot in the X, Y, and Z directions to obtain the corresponding waveform output data.
[0042] Currently, most step counting methods calculate distance using GPS signals and then reverse-engineer the step count. This method is quite effective, but it doesn't work indoors or on devices without GPS signals. Furthermore, GPS accuracy can significantly interfere with the results. To avoid these problems, in some application scenarios of this embodiment, gait information is primarily obtained using accelerometers on the lower limb exoskeleton.
[0043] Specifically, in some application scenarios of this embodiment, the above acceleration data is based on two H48C triaxial accelerometers respectively located at the feet. An MCP3204 analog-to-digital converter is installed on one side of each triaxial accelerometer. The analog-to-digital converter is used to convert the analog voltage output by the triaxial accelerometers into a digital signal output. The formula for converting the raw data collected by the triaxial accelerometers into acceleration data is as follows:
[0044] G = (axis - vRef) × 0.22;
[0045] In the formula, axis and vRef represent the count values obtained by conversion through the MCP3204 analog-to-digital converter;
[0046] G represents the acceleration in the X, Y, and Z directions. By performing waveform processing on this acceleration data based on time data, the corresponding waveform output data can be obtained.
[0047] Preferably, in this embodiment, before the step of obtaining the corresponding waveform output data, the control method further includes:
[0048] Step S101: Perform low-pass filtering and Kalman filtering on the acceleration data to remove noise interference and make the obtained waveform output data smoother.
[0049] Step S110 involves performing gait analysis on the waveform output data to obtain gait information, wherein the gait information includes walking speed and walking cycle. For ease of understanding, this gait information is primarily used for controlling the inflation and deflation of airbags when the human body is in motion. Specifically, in this embodiment, step S110 specifically includes:
[0050] Step S111: Cache multiple sampled values within the current waveform period from the waveform output data, and calculate the median amplitude of the waveform period based on the maximum and minimum values among the sampled values. Use this median amplitude as the dynamic judgment threshold for the signal. In this step, the waveform output data can be viewed as a waveform graph with time on the x-axis and acceleration data on the y-axis. The waveform period is the waveform graph within a preset time period. Typically, when a person is walking, the corresponding waveform graph can be viewed as a sine-like graph. However, due to different motion states, the waveform (waveform amplitude value) varies. Therefore, the judgment threshold needs to be a dynamic value. Using the current judgment threshold as the judgment threshold for the next group ensures that the signal judgment threshold is updated in real time, thereby guaranteeing data accuracy.
[0051] Step S112: Select a first sample value from the plurality of sample values as the first feature point;
[0052] Step S113: Within the waveform period, a second sample value identical to the first sample value is selected as the second feature point, wherein the first sample value and the second sample value are simultaneously within an ascending or descending interval. For ease of understanding, within the waveform period, a first sample value is arbitrarily selected above the current signal determination threshold as the first feature point. Then, after the waveform reaches a peak, it descends to a trough and then passes through the signal determination threshold again. By continuing to select a second sample value identical to the first sample value above the signal determination threshold as the second feature point, the two feature points include two ascending intervals and one descending interval. Because a third sample value identical to the first or second feature point exists within the descending interval, both the first and second sample values need to be simultaneously within an ascending or descending interval.
[0053] Step S114: Calculate the time difference between the second feature point and the first feature point as the walking cycle. Specifically, in this step, the time difference should be within a preset range. Since a person's step time is at least 0.2 seconds and at most 2 seconds, otherwise it is invalid data. Therefore, the walking frequency is 0.5-5 Hz, meaning the walking cycle is 0.2-2 seconds. Based on this gait cycle, gait segmentation facilitates the calculation of other gait information. For ease of understanding, the gait analysis algorithm flowchart is as follows: Figure 2 As shown.
[0054] Step S115: Calculate the average value of the peak and trough of the waveform output data between the first feature point and the second feature point, and use this average value as the signal dynamic determination threshold for the next waveform cycle. Specifically, in this step, the maximum value between the first feature point and the second feature point is the peak, and the minimum value is the trough. The average value of the peak and trough can be used as the signal dynamic determination threshold for the next waveform cycle.
[0055] Step S116: Calculate the real-time step speed based on the acceleration data in the waveform output data using the following formula:
[0056] V = (S n -S n-1 ) / T;
[0057] In the formula, V is the real-time walking speed, T is the real-time walking cycle, and S is the walking speed. n-1 For the distance traveled in the previous moment, S n This represents the distance traveled at the current sampling time.
[0058] To facilitate understanding, in this embodiment, the distance traveled and the speed at the next moment are predicted in order to control the inflation and deflation of the airbag at the next moment.
[0059] The velocity at the current sampling time and the velocity at the next sampling time satisfy the following formula:
[0060]
[0061] In the formula, V n α represents the velocity at the current sampling time. n V is the acceleration at the current sampling moment. n+1 For the velocity at the next sampling time, α n-1 The acceleration is the value at the previous sampling time, and Δt is the time interval between samplings of the acceleration data.
[0062] The distance traveled at the current sampling time and the distance traveled at the next sampling time satisfy the following formula:
[0063]
[0064] In the formula, V n-1 S represents the velocity at the previous sampling time. n+1 The distance at the next sampling time;
[0065] The time interval between the previous sampling time and the next sampling time is the duration of one sampling.
[0066] Furthermore, in some application scenarios of this embodiment, the main control board, based on the current motion state, preset air pressure parameters, delay time parameters, inflation / deflation cycle parameters, and overall inflation / deflation sequence parameters, sequentially opens the corresponding solenoid valves to start the micro-adjustable air pump inflating. The air pressure sensor returns the air pressure parameters of the corresponding cavity in real time until the air pressure parameters reach the preset air pressure range. According to the delay time parameter, when the duration of the air pressure in the corresponding cavity reaches the delay time, the corresponding valve of the corresponding airbag is controlled to open, so that the micro-adjustable air pump begins to deflate. For ease of understanding, the airbag control flowchart is as follows: Figure 3 As shown.
[0067] Step S120: Acquire knee joint angle data and combine it with the gait information to obtain comprehensive gait information. Specifically, in this step, the knee joint angle data is acquired based on rotation angle sensors located on both sides of the mechanical exoskeleton's knee joint. These rotation angle sensors are MPU-103 rotation angle sensors. The MCU-103 rotation angle sensor is a potentiometer-type sensor with an internal ring potentiometer. Its total resistance is 10kΩ, and rotation changes its resistance. For ease of understanding, when the mechanical angle is 333°, the analog voltage output by the angle sensor is converted into a digital signal output, and the output data is:
[0068] D = 333.3° × R / 10kΩ
[0069] Step S130: Determine the human body's motion state based on the comprehensive gait information. Specifically, in this embodiment, step S130 includes:
[0070] Step S131: Determine whether the human body is in a dynamic or static state based on the walking speed;
[0071] Step S132: After determining that the human body is in a static state, determine the human body's motion state based on the acceleration data and the angle data;
[0072] Specifically, in this step, since the magnitude of the acceleration along the X-axis or Y-axis is close to g when the patient is lying supine, on their side, or prone, the magnitude of the acceleration along the X-axis or Y-axis is determined. When the magnitude of the acceleration along the X-axis or Y-axis is close to g, it can be determined that the patient is in a bed rest braking state. That is, when the magnitude of the acceleration data along the X-axis or Y-axis is within the first preset range, the motion state is determined to be a bed rest braking state.
[0073] When the patient is standing, the Z-axis acceleration is close to g. That is, when the value of the Z-axis acceleration data is within the first preset range, the motion state is determined to be a standing state.
[0074] When the angle of the knee joints of the left and right legs is between 45° and 135°, it can be determined that the state is sitting. That is, when the angle data is within the second preset range, the movement state is determined to be sitting.
[0075] Step S133: After determining that the motion state is dynamic, the motion state of the human body is determined based on the waveform output data, the walking cycle, the walking speed and the acceleration data.
[0076] Specifically, in this step, when the walking speed and walking cycle are within a reasonable range (the waveforms of the above waveform output data are symmetrical), that is, when the walking cycle is within the third preset range (see step S114 for details), the movement state is determined to be a walking state.
[0077] The peak of the acceleration curve corresponds to the highest point of the leg during the swing. When walking on flat ground, the sides should show a symmetrical trend. However, when climbing stairs, compared to walking, the height of the single leg is raised higher in the first half of the movement and lower in the second half. That is, in each walking cycle, the distance before the peak is greater than the distance after the peak. When the above condition is met, that is, when the distance before the peak in the waveform output data is greater than the distance after the peak, the motion state is determined to be the climbing state.
[0078] When stationary or moving upwards, the Z-axis axial acceleration is greater than or equal to g due to gravity; when moving downwards, the Z-axis axial acceleration is less than g. When the above conditions are met, i.e., when the value of the Z-axis acceleration is less than a first threshold, the motion state is determined to be a downward movement.
[0079] In this embodiment, after determining the motion state of the current cycle, it is necessary to determine whether the state is a true motion state and not interference. By continuously judging the data and querying whether the motion states of two adjacent cycles are the same, when the motion states of two adjacent cycles are the same, it can be considered a true motion state.
[0080] Furthermore, in this embodiment, after step S130, the method further includes:
[0081] Step S140: When the movement state is a bed rest braking state, control the several airbag groups of the legs to inflate sequentially from the distal end to the proximal end until the air pressure in the airbag group reaches the preset range.
[0082] Step S141: Control the several airbag groups to deflate sequentially from the proximal end to the distal end. Repeat the above inflation and deflation steps until the bed rest immobilization state is exited.
[0083] Specifically, by inflating the airbags fitted around the legs with an appropriate amount of gas, the airbags tightly encase the legs while applying a certain amount of pressure that can be withstood. This pressure penetrates into the blood vessels of the legs. The airbags sequentially inflate, expand, and deflate in a wave-like motion, with a directional, gradual, and cumulative squeezing effect, promoting the return of stagnant venous blood and lymph, accelerating venous blood flow in the limbs, eliminating edema, and promoting blood circulation. By controlling several groups of airbags to deflate sequentially from the proximal end to the distal end, the pressure at the distal end can be ensured to be higher than that at the proximal end. Simultaneously, the cyclical inflation and deflation of the airbags can simulate a physical massage of the leg muscles. This effectively increases the amount of venous blood returning, reduces the burden on the heart's return flow, and decreases the possibility of abnormalities in the leg's venous valves.
[0084] Understandably, in this embodiment, when the above-mentioned motion state is confirmed to be a bed rest braking state, a comprehensive command is issued based on the overall inflation and deflation sequence parameters, the corresponding airbag solenoid valve opens, the micro air pump starts to inflate, the corresponding air pressure sensor provides real-time feedback on the corresponding cavity air pressure, and the solenoid valve closes when the preset range is reached.
[0085] Furthermore, in some application scenarios of this embodiment, the above-mentioned airbag group includes a first airbag group and a second airbag group respectively located on the front and back sides of the thigh, and a third airbag group and a fourth airbag group respectively located on the front and back sides of the calf. The first airbag group includes a first single-cavity airbag, a second single-cavity airbag, and a third single-cavity airbag; the second airbag group includes a fourth single-cavity airbag, a fifth single-cavity airbag, a sixth single-cavity airbag, and a seventh single-cavity airbag; the third airbag group includes an eighth single-cavity airbag and a ninth single-cavity airbag; and the fourth airbag group includes a tenth single-cavity airbag and an eleventh single-cavity airbag. For ease of understanding, as... Figure 4 As shown, the first airbag group (Group A airbag) has 3 sub-airbag cavities, corresponding to the vastus lateralis, rectus femoris, and vastus medialis muscles, respectively; the second airbag group (Group B airbag) has 4 sub-airbag cavities, corresponding to the gracilis, semimembranosus, semitendinosus, and biceps femoris muscles, respectively; the third airbag group (Group C airbag) has 2 sub-airbag cavities, corresponding to the peroneus longus and tibialis anterior muscles, respectively; and the fourth airbag group (Group D airbag) has 2 sub-airbag cavities, which together simulate the gastrocnemius muscle.
[0086] In some application scenarios of this embodiment, prolonged bed rest can easily lead to muscle atrophy, relative insufficient blood volume, increased blood viscosity, and slowed blood flow, resulting in blood stasis and potentially causing deep vein thrombosis in the lower extremities. The reciprocating massage with an airbag accelerates the return of venous blood from the lower extremities, preventing venous thrombosis and muscle atrophy.
[0087] Based on this, when the movement state is a bed rest and immobilization state, firstly, several single-chamber airbags of the third airbag group and the fourth airbag group in the lower leg (distal end) are inflated in a first preset order. Then, several single-chamber airbags of the first airbag group and the second airbag group in the thigh (proximal end) are inflated in a second preset order. When the air pressure of all the single-chamber airbags reaches the preset value, they enter a pressure-holding state and remain there for a preset time. Then, all the single-chamber airbags are deflated simultaneously.
[0088] Specifically, the implementation steps of the above-mentioned bed rest braking mode are as follows:
[0089] 1. Receive mode instructions and determine the corresponding static massage working mode for the airbag;
[0090] 2. Upon receiving the inflation command, open the solenoid valve to inflate and deflate, ensuring that the preset values of each chamber of the airbag are the same;
[0091] 3. Upon receiving the sequential instructions, at the lower leg end, the two sub-airbag cavities within airbag group C are inflated and then deflated counterclockwise. Airbag group D then inflates and deflates its two internal airbag cavities counterclockwise. At the thigh end, starting with airbag group A, the three internal airbag cavities surrounding the thigh are inflated and deflated counterclockwise from the proximal layer. Airbag group B then inflates and deflates its four internal annular airbag cavities counterclockwise from the proximal layer.
[0092] 4. Receive time instructions and determine the duration of the current work cycle and the time interval between the current work cycle and the next work cycle.
[0093] The specific workflow is as follows: the lower leg airbag groups C and D start inflating first, and enter the pressure holding state when the airbag pressure reaches the preset value MaxC / D. At this time, the thigh airbag groups A and B start inflating, and enter the pressure holding state when the airbag pressure reaches the preset value MaxA / B, which lasts for 1 second. Then, the A, B, C, and D airbag groups deflate simultaneously, and enter the pressure holding state when the preset minimum pressure values MinA / B and MinC / D are reached. This is one cycle, and the airbag groups will repeat this cycle in this mode.
[0094] The preset airbag pressure values are: MaxC\D>MaxA\B>MinC\D>MinA\B.
[0095] Furthermore, in this embodiment, after step S130, the method further includes:
[0096] Step S150: When the movement state is standing mode, control the second airbag group, the third airbag group and the fourth airbag group to maintain a low pressure and pressure holding state, and control several single-chamber airbags of the first airbag group to inflate simultaneously, and then deflate after reaching a preset value.
[0097] In some application scenarios of this embodiment, patients with lower limb muscle injuries experience reduced lower limb muscle strength. Compression of blood return from the lower limbs and loss of active muscle contraction can lead to blood stasis in the deep veins, easily forming thrombi. Inflating and deflating an airbag simulates lower limb muscle contraction, passively compressing the lower limb veins, promoting blood return, and preventing blood stasis in the deep veins that could lead to thrombosis. This mode primarily engages the rectus femoris, vastus lateralis, and vastus medialis muscles in the anterior thigh.
[0098] For ease of understanding, the specific implementation steps of the above standing mode are as follows:
[0099] 1. Receive mode instructions and determine the corresponding working mode of the airbag;
[0100] 2. Upon receiving the inflation command, open the solenoid valve to inflate and deflate, ensuring that the preset values of each chamber of the airbag are the same;
[0101] 3. Upon receiving the sequential command, the A airbag group at the front of the thigh will inflate simultaneously around the three airbag chambers No. 1, No. 2, and No. 3 inside the thigh. Once the preset pressure value is reached, the airbags will begin to deflate. This completes one cycle. The C and D airbag groups at the calf end and the B airbag group at the back of the thigh will always maintain a low-pressure state.
[0102] 4. Accept the mode command and de-stand.
[0103] Furthermore, in this embodiment, after step S130, the method further includes:
[0104] Step S160: When the movement state is the sitting mode, firstly control the first airbag group and the seventh single-chamber airbag group to inflate in a third preset order until the air pressure reaches the preset value. Then, control the fourth airbag group to inflate in a fourth preset order until the preset value is reached. Finally, control the first airbag group and the seventh single-chamber airbag group to deflate until the air pressure reaches the preset value.
[0105] In some application scenarios of this embodiment, patients with lower limb muscle injuries experience weakened muscle strength. We use airbag inflation and deflation to simulate muscle contraction. When sitting, the thigh muscles primarily exert force, with the calf muscles playing a secondary role. The thigh airbag provides a wrapping and compressive function, while the calf airbag simulates the operation of a muscle pump, gradually increasing pressure from the proximal to the distal end to promote blood return. In this state, the thigh muscles primarily exert force, with the calf muscles providing auxiliary force.
[0106] For ease of understanding, the specific implementation steps of the above standing mode are as follows:
[0107] 1. Receive mode instructions and determine the corresponding working mode of the airbag;
[0108] 2. Upon receiving the inflation command, open the solenoid valve to inflate and deflate, ensuring that the preset values of each chamber of the airbag are the same;
[0109] 3. Upon receiving sequential instructions, starting with the A group of airbags proximal to the thigh, inflate the No. 1, 2, and 3 airbags in a ring around the thigh counterclockwise from the proximal end. Simultaneously, the B group inflates its No. 4 airbag counterclockwise from the proximal end. The inflation speed is calculated from the acceleration data in the X, Y, and Z directions collected by the program. While maintaining a seated position, the calf muscles engage in force exertion. The C group does not participate in inflation. The D group inflates its No. 1 and 2 sub-airbags counterclockwise to the predetermined value. At the same time, the No. 1, 2, and 3 airbags in the A group and the No. 4 airbag in the B group are appropriately deflated until the air pressure matches the appropriate value determined by the program. Once each airbag group reaches the predetermined inflation value, the inflation state is maintained.
[0110] 4. Accept the mode command and de-sit. The user stands up. At this time, all the airbags in groups A and B of the thighs are inflated, and the airbags in group D are deflated until the user is fully standing.
[0111] Taking one leg as an example, the process is the same for the other leg. The specific workflow is as follows:
[0112] a. The three airbags in the thigh-end A airbag group and the B4 airbag begin to inflate simultaneously, in a counter-clockwise direction; b. When each airbag in a reaches the preset value, the D airbag group begins to inflate, in a counter-clockwise direction; at the same time, each airbag in a is appropriately deflated until the air pressure matches the appropriate value determined by the program.
[0113] c. Once the D airbag group at the lower leg reaches the preset pressure value, airbags A, B, and D maintain their respective inflation levels until the mode changes.
[0114] The steps a, b, and c above form a continuous process, corresponding to the three steps of squatting, sitting down, and maintaining a seated position in the sitting mode.
[0115] Preferably, in this embodiment, after step S130, the method further includes:
[0116] Step S170: When the movement state is walking, control the first airbag group, the seventh single-chamber airbag and the third airbag group to inflate simultaneously in a fifth preset order. When the pressure of the first airbag group, the seventh single-chamber airbag and the third airbag group reaches a preset value, they start to deflate. At this time, control the fourth airbag group to inflate. When the pressure of the fourth airbag group reaches a preset value, it deflates, and control the fourth single-chamber airbag, the fifth single-chamber airbag and the sixth single-chamber airbag to inflate simultaneously.
[0117] In some application scenarios of this embodiment, patients with lower limb muscle injuries are prone to abnormal gait when walking due to muscle weakness. Based on the contraction and relaxation of muscle groups during normal walking, we control the inflation and deflation of the airbag. When the muscles contract, it provides assistance, and when the muscles relax, it wraps and wraps the airbag to reduce the burden on the muscle groups, thus helping the patient walk.
[0118] To make it easy to understand, in this mode, the corresponding muscles of the calf and thigh alternately exert force. The specific implementation steps are as follows:
[0119] 1. Receive mode instructions and determine the corresponding working mode of the airbag;
[0120] 2. Upon receiving the inflation command, open the solenoid valve to inflate and deflate, ensuring that the preset values of each chamber of the airbag are the same;
[0121] 3. Upon receiving sequential instructions, and based on the contraction and relaxation states of muscle groups during normal human walking, the sub-airbags of each airbag group are divided to simulate corresponding muscle groups. The inflation and deflation are controlled to mimic the muscle states during walking. This process uses the collected acceleration data in the X, Y, and Z directions to calculate the inflation speed. The cycle period between the support and swing phases during running is shortened.
[0122] 4. Receive time instructions and determine the time interval between the current work cycle and the next work cycle. Taking one leg as an example, the other leg follows the same process. The specific workflow is as follows:
[0123] a. The A and B4 airbags at the thigh end and the C airbag group at the calf end begin to inflate simultaneously, with the inflation sequence being counterclockwise.
[0124] b. When each airbag in a reaches the preset value, it begins to deflate. At this time, airbag groups 1 and 2 at the lower leg D start to inflate simultaneously.
[0125] c. When the D airbag group at the lower leg reaches the preset pressure value, it immediately begins to deflate. At this time, the three sub-airbags of the B airbag group at the lower leg, namely 1, 2, and 3, begin to inflate simultaneously. The A airbag group, the B airbag group 4, and the C airbag group follow suit and begin to inflate.
[0126] The steps a, b, and c above form a cycle, corresponding to the three processes of lifting the leg, pushing off the leg, and landing the foot in the walking mode.
[0127] Understandably, in some application scenarios of this embodiment, when a person is in a dynamic walking state, the support phase and swing phase of the two legs alternate. When one leg is in the support phase, the other is in the swing phase. During the support phase, the leg bends first and then straightens, playing a major supporting role. During the swing phase, the leg bends first and then straightens, playing a stepping role. When the miniature air pump inflates, the inflation rate is determined by the walking speed. The walking speed and inflation rate are directly proportional, and the inflation rate can be adjusted in real time to match the optimal inflation rate. Because the air bladder cavity has a small volume, the miniature air pump can fill the cavity in a short time.
[0128] Based on the above gait information calculation, different commands are issued. When the acceleration is at its peak, which is the middle of the swing phase, the two airbag groups in the thigh area deflate in the order from the proximal end to the distal end, while the two airbag groups in the lower leg area deflate in the order from the proximal end to the distal end. At the same time, one airbag group in the knee joint deflates. The air pressure sensor provides real-time feedback on the air pressure of the corresponding single-chamber airbag. After reaching the preset range, it waits for the next command.
[0129] Based on the gait information calculations, different commands are issued. When the acceleration (sampled value) is at a trough, which corresponds to the mid-stability phase, the two airbag groups in the thigh inflate sequentially from distal to proximal, while the two airbag groups in the lower leg inflate sequentially from distal to proximal. Simultaneously, one airbag group in the knee joint inflates to a half-saturated state. The air pressure sensor provides real-time feedback on the corresponding single-chamber airbag pressure, and waits for the next command after reaching a preset range.
[0130] Preferably, in this embodiment, after step S130, the method further includes:
[0131] Step S180: When the movement state is the upstairs state, control the first airbag group, the fifth single-chamber airbag, the seventh single-chamber airbag and the tenth single-chamber airbag at the leg in the supporting state to inflate and then deflate, and control the seventh single-chamber airbag and the ninth single-chamber airbag at the leg in the swinging state to inflate and then deflate.
[0132] In some application scenarios of this embodiment, patients with lower limb muscle injuries may find it difficult to climb stairs. Furthermore, due to weak muscle strength, pressure is easily transmitted to the knee joint, potentially causing knee damage. We use an airbag to inflate and deflate, simulating muscle contraction. The airbag tightens when the corresponding muscle contracts and relaxes when it relaxes, providing assistance to patients climbing stairs and reducing knee pressure.
[0133] To put it simply, in this state, the thigh muscles primarily exert force, while the calf muscles exert force secondarily, with the two legs alternating in a cycle. This mainly involves the rectus femoris, vastus lateralis, and vastus medialis in the front of the thigh; the semimembranosus and biceps femoris in the back of the thigh; the medial gastrocnemius in the back of the calf; and the tibialis anterior in the front of the calf.
[0134] The specific implementation steps are as follows:
[0135] 1. Receive status commands and determine the corresponding working mode of the airbag;
[0136] 2. Upon receiving the inflation command, open the solenoid valve to inflate and deflate, ensuring that the preset values of each chamber of the airbag are the same;
[0137] 3. Receiving sequential instructions. During the support phase, the thigh end, starting with the front A airbag group, inflates and deflates the three internal airbag chambers (No. 1, 2, and 3) that encircle the thigh in a ring, as well as the No. 2 and 4 sub-airbags in the rear B airbag group. The lower leg D airbag group inflates and deflates its No. 1 sub-airbag. Transitioning to the swing phase, the No. 4 sub-airbag in the rear B airbag group and the No. 2 airbag in the front C airbag group of the lower leg inflate and deflate. The inflation times of the thigh and lower leg airbag chambers are synchronized. This completes one swing cycle.
[0138] 4. Receive time instructions and determine the time interval between the current work cycle and the next work cycle.
[0139] Preferably, in this embodiment, after step S130, the method further includes:
[0140] Step S190: When the movement state is the downstairs state, control the first airbag group and the ninth single-chamber airbag at the leg in the supporting state to inflate and then deflate, and control the first airbag group, the seventh single-chamber airbag and the ninth single-chamber airbag at the leg in the swinging state to inflate and then deflate.
[0141] In some application scenarios of this embodiment, patients with lower limb muscle injuries, due to weak muscle strength, muscle relaxation and weakness, and poor muscle control, are prone to transmitting pressure to the knee joint during the process of going downstairs, which can cause knee joint damage in severe cases. We use the inflation and deflation of an airbag to simulate muscle contraction, tightening when the corresponding muscle contracts and relaxing when the corresponding muscle relaxes, providing assistance to patients going downstairs and reducing knee pressure.
[0142] To make it easier to understand, this mode is similar to the upstairs mode, but the sub-airbags involved and their inflation sequence are different. The specific implementation steps are as follows:
[0143] 1. Receive status commands and determine the corresponding working mode of the airbag;
[0144] 2. Upon receiving the inflation command, open the solenoid valve to inflate and deflate, ensuring that the preset values of each chamber of the airbag are the same;
[0145] 3. Receiving sequential instructions. During the support phase, the three air bladders (numbers 1, 2, and 3) in the front A air bladder group, which wrap around the thigh in a ring, are inflated and then deflated, along with the second sub-air bladder in the C air bladder group of the calf. Transitioning to the swing phase, the three air bladders in the front A air bladder group (numbers 1, 2, and 3), the fourth sub-air bladder in the rear B air bladder group, and the second sub-air bladder in the front C air bladder group of the calf are inflated and then deflated. The inflation times of the air bladders in the thigh and calf are synchronized. This completes one swing cycle.
[0146] 4. Receive time instructions and determine the time interval between the current work cycle and the next work cycle.
[0147] It should be noted that when the user is in a dynamic state, the inflation and deflation of the airbags are periodically controlled through a pre-programmed sequence, or adaptive inflation and deflation is used to simulate the muscle contraction and relaxation patterns during normal lower limb walking. Simultaneously, the airbags tighten during muscle contraction to promote venous return and blood flow, providing walking assistance to the patient. This mode can be further divided into three states: walking, going upstairs, and going downstairs. In traditional rigid lower limb exoskeletons, the actuator acts on the rigid leg bar, creating a torque at the exoskeleton joints. This torque is transmitted to the legs through the exoskeleton's bindings. The transmitted force is perpendicular to the legs, therefore slippage is not as severe (although slippage of the binding mechanism can still occur due to misalignment between the exoskeleton joints and the human joints). Our optimized anchor point biomimetic muscle design, under full coverage, uses a flexible pneumatic compression design to create a clear force transmission path for the entire device. This path is exactly the same as the force transmission path of a normal human body during walking. It can perfectly transmit the driving force of the entire exoskeleton device to the corresponding force-bearing position of the device, achieving almost zero joint damage while transmitting the corresponding limb assist torque with the highest efficiency. This helps patients obtain the corresponding lower limb support force to the greatest extent to complete their walking needs.
[0148] Understandably, in the prior art, airbags are placed in the legs and joints for wearing comfort, and an inflation system with airbags is configured to ensure the fit between the lower limb exoskeleton and the human body and to adapt to users of different body types. The control method in this application, by adding some components to the existing inflation system, controls the inflation and deflation of the airbags, achieving low cost, compatibility with most lower limb exoskeleton robots, and thereby improving rehabilitation effects.
[0149] In summary, the lower limb exoskeleton airbag control method in the above embodiments of the present invention, by inflating the airbags installed on the lower limb exoskeleton, allows the airbags to tightly wrap around the legs while further applying a certain tolerable pressure to the legs. This pressure penetrates into the blood vessels of the legs. Furthermore, based on gait information, the method intelligently judges the body's movement state. When the body is in a bed-restoring mode, by controlling several airbag groups in the legs to inflate sequentially from the distal to the proximal end until the air pressure within the airbag group reaches a preset range, the method achieves a wave-like inflation, expansion, and deflation of the limbs. This method is directional, gradual, and has a cumulative squeezing effect, promoting the return of stagnant venous blood and lymph, accelerating venous blood flow in the limbs, eliminating edema, and promoting overall health. Blood circulation is improved by controlling the air pressure within the airbag group to reach a preset range. This involves sequentially deflating the airbags from the proximal end to the distal end, ensuring higher pressure at the distal end to facilitate blood return. Simultaneously, the airbag circulation and inflation simulates a physical massage of the leg muscles, effectively increasing venous blood return, reducing the burden on the heart, and decreasing the likelihood of venous valve abnormalities in the legs, thus improving rehabilitation outcomes. Different airbag operation modes are implemented based on different movement states. In dynamic situations, the inflation and deflation of the airbags are dynamically controlled to simulate the muscle expansion and contraction during normal walking. The airbags tighten during muscle contraction, providing power and offering support, fit, and protection during walking.
[0150] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0151] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.
Claims
1. A lower limb exoskeleton, comprising a plurality of air sacs, and executing a method for controlling the air sacs of a lower limb exoskeleton, characterized in that, Includes the following steps: Acquire the acceleration data of the feet in the X, Y, and Z directions to obtain the corresponding waveform output data; Gait information is obtained by performing gait analysis on the waveform output data, wherein the gait information includes walking speed and walking cycle; Knee joint angle data is acquired and combined with the gait information to obtain comprehensive gait information; The movement state of the human body is determined based on the comprehensive gait information. When the movement state is the bed rest braking state, the several airbag groups of the legs are controlled to inflate sequentially from the distal end to the proximal end until the air pressure in the airbag group reaches the preset range, and then the several airbag groups are controlled to deflate sequentially from the proximal end to the distal end.
2. The lower limb exoskeleton according to claim 1, characterized in that, The steps for determining the human body's motion state based on the comprehensive gait information specifically include: The walking speed is used to determine whether the human body is in a dynamic or static state. Once the human body is determined to be in a static state, the motion state of the human body is determined based on the acceleration data and the angle data. Once the motion state is determined to be dynamic, the motion state of the human body is determined based on the waveform output data, the walking cycle, the walking speed, and the acceleration data.
3. The lower limb exoskeleton according to claim 2, characterized in that, The step of determining the motion state of the human body based on the acceleration data and the angle data specifically includes: When the magnitude of the acceleration data along the X-axis or Y-axis is within a first preset range, the motion state is determined to be a bed rest braking state. When the magnitude of the acceleration data along the Z-axis is within the first preset range, the motion state is determined to be a standing state. When the angle data is within the second preset range, the motion state is determined to be a sitting state.
4. The lower limb exoskeleton according to claim 1, characterized in that, The airbag group includes a first airbag group and a second airbag group respectively located on the front and back sides of the thigh, and a third airbag group and a fourth airbag group respectively located on the front and back sides of the calf. The first airbag group includes a first single-cavity airbag, a second single-cavity airbag and a third single-cavity airbag. The second airbag group includes a fourth single-cavity airbag, a fifth single-cavity airbag, a sixth single-cavity airbag and a seventh single-cavity airbag. The third airbag group includes an eighth single-cavity airbag and a ninth single-cavity airbag. The fourth airbag group includes a tenth single-cavity airbag and an eleventh single-cavity airbag. When the movement state is the bed rest braking state, firstly, the third airbag group and the fourth airbag group of the lower leg are controlled to inflate several single-chamber airbags in a first preset order. Then, the first airbag group and the second airbag group of the thigh are controlled to inflate several single-chamber airbags in a second preset order. When the air pressure of all the single-chamber airbags reaches the preset value, the pressure is maintained for a preset time, and then all the single-chamber airbags are controlled to deflate simultaneously.
5. A lower limb exoskeleton according to claim 4, characterized in that, When the movement state is standing mode, the second airbag group, the third airbag group and the fourth airbag group are controlled to maintain a low pressure and pressure holding state, and several single-chamber airbags of the first airbag group are controlled to inflate simultaneously, and then deflating after reaching the preset value.
6. A lower limb exoskeleton according to claim 4, characterized in that, When the movement state is the sitting mode, firstly, the first airbag group and the seventh single-chamber airbag group are controlled to inflate in a third preset order until the air pressure reaches the preset value. Then, the fourth airbag group is controlled to inflate in a fourth preset order until the preset value is reached. Finally, the first airbag group and the seventh single-chamber airbag group are controlled to deflate until the air pressure reaches the preset value.
7. A lower limb exoskeleton according to claim 2, characterized in that, The step of determining the human body's motion state based on the waveform output data, the walking cycle, the walking speed, and the acceleration data specifically includes: When the walking cycle is within a third preset range, the movement state is determined to be a walking state; When the path of the peak in the waveform output data is greater than the path of the peak behind it, the motion state is determined to be an upstairs state. When the value of the acceleration data along the Z-axis is less than the first threshold, the motion state is determined to be a downstairs state.
8. A lower limb exoskeleton according to claim 4, characterized in that, When the movement state is walking, the first airbag group, the seventh single-chamber airbag and the third airbag group are controlled to inflate simultaneously in a fifth preset order. When the pressure of the first airbag group, the seventh single-chamber airbag and the third airbag group reaches a preset value, they start to deflate. At this time, the fourth airbag group is controlled to inflate. When the pressure of the fourth airbag group reaches a preset value, it deflates, and the fourth single-chamber airbag, the fifth single-chamber airbag and the sixth single-chamber airbag are controlled to inflate simultaneously.
9. A lower limb exoskeleton according to claim 4, characterized in that, When the movement state is the upstairs state, the first airbag group, the fifth single-chamber airbag, the seventh single-chamber airbag and the tenth single-chamber airbag at the leg in the supporting state are inflated and then deflated, and the seventh single-chamber airbag and the ninth single-chamber airbag at the leg in the swinging state are inflated and then deflated.
10. A lower limb exoskeleton according to claim 4, characterized in that, When the movement state is the downstairs state, the first airbag group and the ninth single-chamber airbag at the leg in the supporting state are inflated and then deflated, and the first airbag group, the seventh single-chamber airbag and the ninth single-chamber airbag at the leg in the swinging state are inflated and then deflated.