A wearable flexible knee joint assisting garment

Abstract

The present invention discloses a wearable flexible knee joint assist suit, comprising a portable control system, a left-leg assist suit wearing component, a right-leg assist suit wearing component, and an attitude reference system component (AHRS). The attitude reference system component can obtain the swing angle parameters of the human body's thigh and calf relative to the ground in real time and feed them back to the portable control system. The portable control system uses a sliding mode variable structure control method based on a double closed-loop mechanism according to the user's gait and movement pattern to control the air pressure of the left-leg assist suit wearing component and the right-leg assist suit wearing component in real time, providing an air pressure force consistent with the user's gait and movement pattern in the sagittal plane of the human body from the back of the thigh and calf of the left or right leg and the side of the knee pit during walking, and providing a torque for the knee joint to stretch within the range of 0°-180°, thereby achieving the purpose of assisting knee joint movement.

Description

Technical Field

[0001] The present invention relates to a wearable flexible knee joint power-assisting suit, belonging to the technical field of flexible exoskeletons, flexible power-assisting suits, and flexible wearable power-assisting equipment. Background Art

[0002] Wearable flexible knee-assistance suits are a product of the integration of flexible exoskeletons and medical engineering technologies. They primarily aim to assist the knee joint, using flexible components instead of rigid structures. Flexible airbags or Bowden ropes directly act on the knee joint, eliminating the rigid structural constraints and enabling the knee joint to flex and extend according to the wearer's intended movements. This reduces the wearer's burden, enhances limb strength, and promotes the recovery of normal motor function. These suits can also provide partial walking assistance to elderly individuals with limited walking ability, improving their ability to walk, thereby enhancing their quality of life and reducing social burdens. Typical flexible knee exoskeletons currently available include the knee-assistance pants developed by Sasaki et al. at Okayama University in Japan, which utilizes aluminum-film inflatable airbags; the knee-assistance suit developed by Mohri et al. at Chuo University in Japan, which utilizes straight-fiber pneumatic artificial muscles as drive units to enhance knee strength and reduce waist load when lifting objects; and the knee tendon-suit developed by Park et al. at Seoul National University in South Korea, which utilizes Bowden ropes.

[0003] The stiffness of the Bowden cable can be adjusted to adjust the overall drive system stiffness of a cable-driven flexible knee-assisted exosuit. Furthermore, the cable's remote transmission feature shifts the system's weight to the waist, reducing inertia and energy consumption. However, the stick-slip effect of cable transmission and the dynamic asymmetry of unidirectional cable transmission present challenges for subsequent position and tension control.

[0004] Pneumatic flexible knee joint assistance suits generally use pneumatic muscles as drivers, which have the characteristics of high power density, light weight and inherent softness. However, the high nonlinearity in the pneumatic muscle driving process makes it difficult to achieve high control accuracy, which also limits its in-depth application in the field of flexible exoskeletons. In addition, due to the high threshold of pneumatic muscles, lower limb exoskeletons driven by pneumatic muscles generally require an air source with a large flow rate and air pressure, which brings challenges to the miniaturization and portability of flexible lower limb exoskeletons.

[0005] In summary, how to select appropriate flexible structural materials and driving methods, and how to design the layout of flexible materials to improve the flexibility and power-assistance efficiency of the exoskeleton are the key to the research of flexible knee joint power-assistance suit systems, and are also the difficult problems that urgently need to be solved in the field of flexible lower limb exoskeletons. Summary of the Invention

[0006] The purpose of the present invention is to address the defects of the above-mentioned prior art and provide a wearable flexible knee joint assist suit, comprising the wearable flexible knee joint assist suit including a portable control system, a flexible assist suit left leg wear component, a flexible assist suit right leg wear component, a strap, a waist fixing belt, an air tube (A) and an air tube (B), etc. The portable control system controls the air pressure of the flexible assist suit left leg wear component and the flexible assist suit right leg wear component in real time according to the user's gait and movement pattern, and provides an auxiliary torque to assist the knee joint movement according to the user's gait and movement pattern during walking, thereby achieving the purpose of assisting the knee joint movement.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is:

[0008] A wearable flexible knee joint assist suit, comprising:

[0009] A portable control system capable of processing the acquired data and controlling the drive and air pressure output;

[0010] The left leg wearable component of the power-assist suit is used to be worn on the left knee joint. It can provide pressure from the back of the left thigh and calf, as well as the knee pit, in the sagittal plane of the human body, providing a torque for the left knee joint to extend within the range of 0°-180°, thereby assisting the extension of the left knee joint;

[0011] The right leg wearable component of the power-assist suit is used to be worn on the right knee joint. It can provide pressure from the back of the thigh and calf of the right leg, as well as the side of the knee pit in the human body's sagittal plane, providing a torque for the right knee joint to extend within the range of 0°-180°, thereby assisting the right knee joint to extend;

[0012] An attitude reference system component (AHRS) capable of acquiring the swing angle parameters of the left and right thighs relative to the ground in real time, providing the portable control system with the user's gait and movement pattern data;

[0013] The portable control system can control the air pressure of the left-leg wearable component and the right-leg wearable component of the power-assist suit in real time according to the user's gait and movement pattern, providing the user with a torque that is consistent with his or her gait and movement pattern and assists the knee joint to extend within the range of 0°-180°, thereby assisting the extension of the knee joints of the left and right legs.

[0014] Preferably, the wearable flexible knee joint assist suit further comprises:

[0015] A shoulder strap, used for a user to carry the portable control system on both shoulders;

[0016] A waist fixing belt, used for fixing the portable control system on the user's waist;

[0017] Air pipe A, which is used to deliver the air pressure of the portable control system to the left leg wearing component of the power-assisting suit;

[0018] Air pipe B is used to deliver the air pressure of the portable control system to the right leg wearing component of the power-assisting suit.

[0019] Preferably, the portable control system comprises: a control box body, a controller, an air pump driver, an air pump, a two-position three-way positive pressure air valve, an air pressure sensor, a battery pack, and an electrical connector;

[0020] The controller is used to receive, calculate, process data, and send instructions;

[0021] The air pump is used to provide positive pressure for the left leg wearing component of the flexible power-assisting suit and the right leg wearing component of the flexible power-assisting suit;

[0022] The two-position three-way positive pressure air valve can switch the positive pressure output of the air pump to different airflow delivery channels between the left leg wear component of the flexible power-assist suit and the right leg wear component of the flexible power-assist suit, and switch the positive pressure and negative pressure of the left leg wear component of the flexible power-assist suit and the right leg wear component of the flexible power-assist suit.

[0023] Preferably, the left leg wearing component of the power-assist suit and the right leg wearing component of the power-assist suit further include: an enveloping knee pad, a TPU positive pressure driver, a heading reference system component, Velcro A and Velcro B respectively.

[0024] Preferably, the wraparound kneepad includes a textured side and a smooth side;

[0025] The fur side is located on the outside of the left leg wearing component of the flexible power-assisting suit and the right leg wearing component of the flexible power-assisting suit;

[0026] The smooth side is located on the inner side of the left leg wearing component of the flexible power-assisting suit and the right leg wearing component of the flexible power-assisting suit.

[0027] Preferably, the attitude reference system component can detect the rotation angles of the left and right thighs and calves in the sagittal plane in real time, and can also calculate the knee joint angle by subtracting the rotation angles of the thigh and calf on the same side, and feed it back to the portable control system to provide the portable control system with user gait and movement pattern data.

[0028] Preferably, the TPU positive pressure driver is made of TPU fabric material, which can be rotated from a bent state at any angle to a straight state under the action of air pressure, generating rotational motion and also outputting torque externally;

[0029] The TPU positive pressure driver is sewn to the fleece side of the wraparound fleece lycra knee pad with the Y-axis of the wraparound knee pad as the axis of symmetry. It can accept positive pressure loading and unloading, and can provide pressure force from the back of the thigh and calf, as well as the side of the knee pit in the sagittal plane of the human body, providing the knee joint with a torque for extension within the range of 0°-180°, thereby assisting the extension of the knee joints of the left and right legs.

[0030] Preferably, the Velcro A is sewn on the wraparound knee pad to fix and adjust the position of the attitude reference system component, so that the attitude reference system component is located in the coronal plane of the human body when the left leg wearing component of the flexible power-assist suit and the right leg wearing component of the flexible power-assist suit are worn.

[0031] Preferably, the Velcro B is sewn to one end of the wraparound knee pad and fastened with the fleece surface of the outer side of the wraparound knee pad, and is used to fix the left leg wearing component and the right leg wearing component of the flexible power-assisting suit at the corresponding positions of the user's knee joint and to adjust the tightness.

[0032] Preferably, the wearable flexible knee joint assist suit further comprises:

[0033] The air pressure sensor can collect the pressure information of the TPU positive pressure driver in real time and feed it back to the controller in real time;

[0034] The controller uses the attitude reference system component (AHRS), gait estimation model and knee joint torque model to identify the current walking gait of the human body and calculate the torque command and air pressure command; the air pump controller uses a sliding mode variable structure control method based on a double closed-loop mechanism to construct an air pressure-speed-valve command calculation model, and calculates in real time the air pump speed and air valve switching value required by the model; the micro air pump and the two-position three-way positive pressure air valve perform corresponding actions according to the instructions of the air pump controller, and provide the user's knee joint with an auxiliary torque that matches the gait cycle and knee joint torque requirements through a flexible power-assistance execution system.

[0035] Preferably, the sliding-mode variable structure control method based on a dual closed-loop mechanism builds an inner-loop speed closed-loop control module on top of the closed-loop pressure regulation to accelerate pressure regulation. To achieve real-time pressure regulation, the system incorporates a closed-loop control mechanism. When the actual pressure exceeds the set value, the air pump speed is primarily adjusted through closed-loop control to quickly bring the actual pressure to the set value. When the actual pressure is significantly lower than the set value, the air is inflated primarily by opening the air valve, allowing the actual pressure in the TPU positive pressure actuator to quickly reach the set value, ultimately achieving the desired torque output by the TPU positive pressure actuator. The assist torque curve required by the human body in this system changes dynamically. To ensure that the TPU positive pressure actuator provides real-time and accurate assist torque at different times, the system requires rapid dynamic response. Therefore, further optimization of the closed-loop control link, which determines system performance, is necessary. Based on the above considerations, an inner-loop speed closed-loop control module is built on top of the closed-loop pressure regulation to accelerate pressure regulation. To further enhance the system's dynamic characteristics, a sliding-mode controller with variable structure control is introduced, replacing the traditional PI controller. The essence of the sliding mode controller is to make the closed-loop control system have different structures by switching switches. Let S(t) be the switching function, and when S(t) = 0, it is the sliding mode surface. + (t) and u-(t) are the controllers on the left and right sides of the sliding surface, respectively. By switching different controllers, feedback can quickly reach the given target, ultimately achieving better dynamic response, which can be specifically expressed as:

[0036]

[0037] To implement a sliding mode controller, we first construct a sliding surface. The variable to be regulated is the speed, and ultimately the air pressure is regulated. Since air pressure is the integral of the speed, the sliding surface is constructed based on these two variables as follows:

[0038]

[0039]

[0040] S=X1+CX2 (4)

[0041] in, w r are the given speed and actual speed of the motor respectively, and S is the switching function

[0042] The motion equation of the known motor is:

[0043]

[0044] Set the air pressure error expression:

[0045] e=p * -p (6)

[0046] w r =ke (7)

[0047] Combined with the above formula, we can get the derivative of S:

[0048]

[0049] Among them, T e is the output torque, T l is the load torque, J is the moment of inertia, P * is the given air pressure, p is the actual air pressure, k and C are constants.

[0050] After selecting the sliding surface, you also need to select the sliding mode control rate. To speed up the convergence, select the exponential convergence rate. Therefore, the sliding mode control rate is set as:

[0051]

[0052] Among them: ξ, k2 are constants

[0053]

[0054] Combining the above equations, we can get the expression of output torque, that is, the output of the sliding mode controller is:

[0055]

[0056] By introducing a sliding mode controller, the dynamic response of the system is further improved, thereby better enhancing the system performance; on this basis, the drive module control unit calculates in real time the control instructions for the air pump and the switching instructions for the two-position three-way positive pressure air valve based on the given air pressure value and the detected air pressure and speed information; the two-position three-way positive pressure air valve and the air pump perform corresponding actions according to the controller instructions, providing a quantitative positive pressure for the TPU positive pressure driver.

[0057] Compared with the existing technology, the wearable flexible knee joint assist suit of the present invention adopts a TPU positive pressure driver as the extension torque execution component of the knee joint. The TPU positive pressure driver can provide pressure force from the posterior side of the thigh and calf, as well as the side of the knee pit in the sagittal plane of the human body, providing the knee joint with a torque for extension within the range of 0°-180°, assisting the extension of the knee joints of the left and right legs. This structural form is more direct and effective than the flexible knee joint driver structure in which the driver is installed on the outside of the thigh and calf, is less likely to produce deflection, and has higher driving efficiency.

[0058] Compared with the existing technology, the present invention adopts a TPU positive pressure driver as the extension torque execution component of the knee joint, overcoming the shortcomings of rigid mechanisms such as general leg-assisting equipment or exoskeleton robots, such as large inertia, easy to cause mechanical inertia damage to the human lower limb joints, poor safety and comfort, and significantly improving the safety and comfort of the equipment.

[0059] Compared with the existing technology, the wearable flexible knee joint assist suit described in the present invention overcomes the shortcomings of conventional rigid exoskeleton robots, such as being heavy, unable to be put on and taken off quickly, and users' lack of psychological recognition of its appearance. It has fewer parts, less human-machine interference, a simple structure, and is easy to use. It effectively reduces the mass and inertia of the assist device, and has the advantages of being easy to wear and having a high degree of psychological recognition among users. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 This is a front view of the wearable flexible knee joint assist garment of the present invention;

[0061] Figure 2 This is a right side view of the wearable flexible knee joint assist garment of the present invention;

[0062] Figure 3 2. It is a rear view of the wearable flexible knee joint assist suit of the present invention;

[0063] Figure 4 yes Figure 1 Expanded structural diagram of the left leg wearing component of the medium-assisted suit (fur side);

[0064] Figure 5 yes Figure 1 Expanded structural diagram of the inner side (glossy side) of the left leg wearing component of the medium-assisted suit;

[0065] Figure 6 yes Figure 1 Expanded structural diagram of the outer side (fur side) of the right leg wearing component of the medium-assisted suit;

[0066] Figure 7 yes Figure 1 Expanded structural diagram of the inside (glossy side) of the right leg wearing component of the medium-assisted suit;

[0067] Figure 8 This is a diagram of the overall control scheme of the wearable flexible knee joint assist suit of the present invention;

[0068] Figure 9 This is a control block diagram of the air pressure regulation module of the wearable flexible knee joint power-assisting suit of the present invention.

[0069] The meanings of the reference numerals are as follows:

[0070] 1. Portable control system; 2. Flexible power suit left leg wearing component; 3. Flexible power suit right leg wearing component; 4. Strap; 5. Waist fixing belt; 6. Trachea A; 7. Trachea B.

[0071] 101. Wraparound fleece-faced Lycra (OK fabric) knee pads; 102. TPU positive pressure actuator; 103. Attitude and Heading Reference System (AHRS) assembly; 104. Electrical connector (male); 105. Velcro A (female, fleece side); 106. Velcro B (male, hook side). DETAILED DESCRIPTION

[0072] The present invention will be further described below with reference to the accompanying drawings and specific implementation examples, but this does not limit the present invention.

[0073] The invention provides a wearable flexible knee joint power-assisting garment. Figure 1 、 2 3 are the front view (front view), left view and back view of the wearable flexible knee joint assist suit. Figure 1 , as shown in Figures 2 and 3, the wearable flexible knee joint power-assist suit includes a portable control system 1, a flexible power-assist suit left leg wear component 2, a flexible power-assist suit right leg wear component 3, a shoulder strap 4, a waist fixing belt 5, a trachea (A) 6, and a trachea (B) 7. The user can carry the portable control system 1 on his shoulders through the shoulder strap 4 and the waist fixing belt 5, and fix it at the waist. The flexible power-assist suit left leg wear component 2 and the flexible power-assist suit right leg wear component 3 are worn on the corresponding parts of the thigh, calf and knee joint of the left and right legs respectively. The portable control system 1 is connected to the flexible power-assist suit left leg wear component 2 and the flexible power-assist suit right leg wear component 3 through the trachea A 6 and the trachea B 7, respectively, to form an air pressure transmission channel.

[0074] The portable control system 1 includes a control box body, a controller, a micro air pump, a two-position three-way positive pressure air valve, an air pressure sensor, a lithium battery pack, and an electrical connector (female connector). The controller is the main command unit for data reception, calculation, processing, and instruction transmission of the wearable flexible knee joint assist suit. The micro air pump is the power source of the wearable flexible knee joint assist suit, providing positive pressure for the flexible assist suit left leg wear component 2 and the flexible assist suit right leg wear component 3; the two-position three-way positive pressure air valve is a three-way solenoid valve that can realize the switching of the micro air pump positive pressure output to different air flow delivery channels between the flexible assist suit left leg wear component 2 and the flexible assist suit right leg wear component 3, as well as the positive and negative pressure switching of the flexible assist suit left leg wear component 2 and the flexible assist suit right leg wear component 3.

[0075] Figure 4 and Figure 5They are respectively the outer side (fur side) and the inner side (smooth side) structural diagram of the left leg wearing component 2 of the flexible power-assisting suit, Figure 6 and Figure 7 The diagrams are respectively the outer side (fur side) and the inner side (smooth side) of the flexible power-assist suit's right leg wear component 3. The flexible power-assist suit's left leg wear component 2 and the flexible power-assist suit's right leg wear component 3 each include an enclosed fleece-surface Lycra (OK cloth) knee pad 101, a TPU positive pressure driver 102, an attitude reference system component (AHRS) 103, an electrical connector (male) 104, Velcro A (female) 105, and Velcro B (male) 106.

[0076] The wraparound fleece lycra (OK cloth) knee pad 101 is divided into a fleece side and a smooth side, the fleece side being the outer side of the flexible power-assisting suit left leg wearing component 2 and the flexible power-assisting suit right leg wearing component 3; the smooth side being the inner side of the flexible power-assisting suit left leg wearing component 2 and the flexible power-assisting suit right leg wearing component 3.

[0077] The TPU positive pressure driver 102 is made of TPU fabric material and is the driving element of the left leg wear component 2 and the right leg wear component 3 of the power-assisted suit. Under the action of air pressure, it can be rotated from a bent state at any angle to a straight state, generating rotational motion and also outputting torque to the outside. The TPU positive pressure driver 102 is sewn to the fleece side of the enclosed fleece lycra (OK cloth) knee pad 101 with the Y axis of the enclosed fleece lycra knee pad 101 as the axis of symmetry. It can accept positive pressure loading and unloading, and can provide pressure force from the back of the thigh and calf, as well as the knee pit side in the sagittal plane of the human body, providing a torque for the knee joint to extend within the range of 0°-180°, thereby assisting the extension of the knee joints of the left and right legs.

[0078] The Velcro A (female surface) 105 is sewn onto the surrounding fleece lycra (OK cloth) knee pad 101 to fix the attitude reference system assembly (AHRS) 103. Figure 5 and Figure 7As shown, the difference between the position of the Velcro A (female surface) 105 in the flexible power-assist suit left leg wearing component 2 and the flexible power-assist suit right leg wearing component 3 is that: the two Velcro A (female surface) 105 in the flexible power-assist suit left leg wearing component 2 are located on the right side of the smooth side of the enclosed fleece lycra (OK cloth) knee pad 101; while the two Velcro A (female surface) 105 on the flexible power-assist suit right leg wearing component 3 are located on the left side of the smooth side of the enclosed fleece lycra (OK cloth) knee pad 101. The attitude reference system assembly (AHRS) 103 is attached to the Velcro A (fleece surface) 105 and the Velcro B (female surface) 106 by means of adhesive-backed Velcro (hook surface). The position of the attitude reference system assembly (AHRS) 103 on the Velcro A (female surface) 105 and the Velcro B (female surface) 106 can be adjusted. The attitude and heading reference system assembly (AHRS) 103 is connected to the electrical connector (female) of the portable control system 1 via the electrical connector (male) 104. The attitude and heading reference system assembly (AHRS) 103 can obtain the motion parameters of the left and right calves and thighs relative to the ground in real time and feed them back to the controller.

[0079] like Figure 5 and Figure 7 As shown, the Velcro B (hook surface) 106 is sewn to one end of the enclosed fleece lycra knee pad 101, and the difference between its position in the flexible power-assist suit left leg wearing component 2 and the flexible power-assist suit right leg wearing component 3 is that: the Velcro B (hook surface) 106 in the flexible power-assist suit left leg wearing component 2 is located at the right end of the fleece side of the enclosed fleece lycra (OK cloth) knee pad 101; and the Velcro B (hook surface) 106 in the flexible power-assist suit right leg wearing component 3 is located at the left end of the fleece side of the enclosed fleece lycra (OK cloth) knee pad 101. The position of the Velcro B (hook surface) 106 in the flexible power-assist suit left leg wearing component 2 and the flexible power-assist suit right leg wearing component 3 is mainly designed based on the habit of right-handed people wearing enclosed knee pads. After the flexible power-assist suit left leg wearing component 2 and the flexible power-assist suit right leg wearing component 3 are worn on the user's left leg, right leg and corresponding knee joint positions, the Velcro B (hook surface) 106 can be fastened with the fleece surface of the outer side of the surrounding fleece Lycra knee pad 101 to complete the position fixation and tightness adjustment of the flexible power-assist suit left leg wearing component 2 and the flexible power-assist suit right leg wearing component 3. Figure 1, 3 and 5, when the flexible power-assist suit left-leg wearing component 2 and the flexible power-assist suit right-leg wearing component 3 are worn, the attitude reference system component (AHRS) 103 is located on the outside of the thighs and calves of both legs, and its position can be adjusted by adjusting the fitting position of the attitude reference system component (AHRS) 103 on the Velcro A (mother surface) 105 in the X-axis direction so that the attitude reference system component (AHRS) 103 is located in the coronal plane of the human body.

[0080] Figure 8 This is a diagram of the overall control scheme of the wearable flexible knee joint power-assist suit of the present invention. As shown in the figure, the controller adopts the attitude reference system component (AHRS) 103, the gait estimation model and the knee joint torque model to identify the current walking gait of the human body and calculate the torque instruction and the air pressure instruction; the air pump controller uses the sliding mode variable structure control method based on the double closed-loop mechanism to construct an air pressure-speed-valve instruction calculation model, and calculates the air pump speed and air valve switching value required by the model in real time; the micro air pump and the positive pressure air valve perform corresponding actions according to the instructions of the air pump controller, and provide the user's knee joint with an auxiliary torque that matches the gait cycle and knee joint torque requirements through the flexible power-assist execution system.

[0081] The sliding mode variable structure control method based on a dual closed-loop mechanism builds an inner-loop speed closed-loop control module on top of the closed-loop pressure regulation to accelerate pressure regulation. To achieve real-time pressure regulation, the system incorporates a closed-loop control mechanism. When the actual pressure exceeds the set value, the air pump speed is adjusted primarily through closed-loop control to quickly bring the actual pressure to the set value. When the actual pressure is significantly lower than the set value, the air valve is opened to inflate the air, rapidly bringing the actual pressure of the TPU positive pressure actuator 102 to the set value, ultimately achieving the desired torque output from the TPU positive pressure actuator 102. The assist torque curve required by the human body in this system changes dynamically. To ensure that the TPU positive pressure actuator 102 provides real-time and accurate assist torque at different times, the system requires rapid dynamic response. Therefore, further optimization of the closed-loop control link, which determines system performance, is necessary. Based on these considerations, an inner-loop speed closed-loop control module is built on top of the closed-loop pressure regulation to accelerate pressure regulation. In order to further improve the dynamic characteristics of the system, based on the above, a sliding mode controller with variable structure control is introduced to replace the traditional PI controller. The system control block diagram is as follows: Figure 9 As shown. The essence of the sliding mode controller is to make the closed-loop control system have different structures by switching switches. Let S(t) be the switching function, and when S(t) = 0, it is the sliding mode surface. + (t) and u -(t) are the controllers on the left and right sides of the sliding surface. By switching different controllers, feedback can quickly reach the given target, ultimately achieving better dynamic response, which can be specifically expressed as:

[0082]

[0083] To implement a sliding mode controller, we first construct a sliding surface. The variable to be regulated is the speed, and the ultimate target is the air pressure, which is the integral of the speed. Therefore, we construct a sliding surface based on these two variables as follows:

[0084]

[0085]

[0086] S=X1+CX2 (4)

[0087] in, w r are the given speed and actual speed of the motor respectively, and S is the switching function

[0088] The motion equation of the known motor is:

[0089]

[0090] Set the air pressure error expression:

[0091] e=p * -p (6)

[0092] w r =ke (7)

[0093] Combined with the above formula, we can get the derivative of S:

[0094]

[0095] Among them, T e is the output torque, T l is the load torque, J is the moment of inertia, P * is the given air pressure, p is the actual air pressure, k and C are constants.

[0096] After selecting the sliding surface, you also need to select the sliding mode control rate. To speed up the convergence, select the exponential convergence rate. Therefore, the sliding mode control rate is set as:

[0097]

[0098] in:

[0099]

[0100] ξ and k2 are constants.

[0101] Combining the above equations, we can get the expression of output torque, that is, the output of the sliding mode controller is:

[0102]

[0103] By introducing the sliding mode controller, the dynamic response of the system is further improved, thereby better improving the system performance; on this basis, the drive module control unit calculates the control instructions of the air pump and the switching instructions of the two-position three-way positive pressure air valve in real time according to the given air pressure value and the detected air pressure and speed information; the two-position three-way positive pressure air valve and the air pump perform corresponding actions according to the controller instructions to provide a quantitative positive pressure for the TPU positive pressure driver 102.

[0104] The embodiment described above is only one of the preferred specific implementation methods of the present invention. Common changes and substitutions made by those skilled in the art within the scope of the technical solution of the present invention should be included in the protection scope of the present invention.

Claims

1. A wearable flexible knee joint assist suit, comprising: A portable control system capable of processing the acquired data and controlling the drive and air pressure output; The left leg wearable component of the power-assist suit is used to be worn on the left knee joint. It can provide pressure from the back of the left thigh and calf, as well as the knee pit, in the sagittal plane of the human body, providing a torque for the left knee joint to extend within the range of 0°-180°, thereby assisting the extension of the left knee joint; The right leg wearable component of the power-assist suit is used to be worn on the right knee joint. It can provide pressure from the back of the thigh and calf of the right leg, as well as the side of the knee pit in the human body's sagittal plane, providing a torque for the right knee joint to extend within the range of 0°-180°, thereby assisting the right knee joint to extend; An attitude reference system component (AHRS) capable of acquiring the swing angle parameters of the left and right thighs relative to the ground in real time, providing the portable control system with the user's gait and movement pattern data; The portable control system can control the air pressure of the left and right leg wear components of the power-assist suit in real time according to the user's gait and movement pattern, providing the user with a torque that assists the knee joint to extend within the range of 0°-180° consistent with their gait and movement pattern, thereby assisting the extension of the knee joints of both legs; The portable control system includes: a control box body, a controller, an air pump driver, an air pump, a two-position three-way positive pressure air valve, an air pressure sensor, a speed detection unit, a battery pack, and an electrical connector; The controller is used to receive, calculate, process data, and send instructions; The air pump is used to provide positive pressure for the left leg wearing component of the power-assist suit and the right leg wearing component of the power-assist suit; The two-position three-way positive pressure valve can switch the positive pressure output of the air pump to different air flow delivery channels between the left leg wearing component and the right leg wearing component of the power-assist suit, and switch the positive pressure and negative pressure of the left leg wearing component and the right leg wearing component of the power-assist suit; The left leg wearing component and the right leg wearing component of the power-assist suit further include: a wrap-around knee pad, a TPU positive pressure driver, a heading reference system component, a Velcro A and a Velcro B; The wearable flexible knee joint assist suit further comprises: The air pressure sensor can collect the pressure information of the TPU positive pressure driver in real time and feed it back to the controller in real time; The controller uses the attitude reference system component (AHRS), gait estimation model, and knee joint torque model to identify the current walking gait of the human body and calculate torque instructions and air pressure instructions. The air pump controller uses a sliding mode variable structure control method based on a double closed-loop mechanism to construct an air pressure-speed-valve instruction calculation model, and calculates the air pump speed and air valve switching amount required by the model in real time. The micro air pump and the two-position three-way positive pressure air valve perform corresponding actions according to the instructions of the air pump controller, and provide the user's knee joint with an auxiliary torque that matches the gait cycle and knee joint torque requirements through the flexible power-assistance execution system. The sliding mode variable structure control method based on the dual closed-loop mechanism is to build an inner-loop speed closed-loop control module on the basis of the air pressure closed-loop control to speed up the air pressure control. The sliding mode variable structure control method based on the double closed-loop mechanism sets u(t) as the sliding mode controller, S(t) as the switching function, and when S(t)=0, it is the sliding mode surface; u + (t) and u - (t) are the controllers on the left and right sides of the sliding surface respectively. By switching different controllers, feedback can quickly reach the given target, and ultimately achieve better dynamic response, which can be specifically expressed as: To implement the sliding mode controller, we first construct a sliding surface. The variable to be regulated is the speed, and the final variable to be regulated is the air pressure, which is the integral of the speed. Therefore, the sliding surface is constructed based on these two quantities as follows: S=X1+CX2 (4) in, w r are the given speed and actual speed of the motor respectively, and S is the switching function; The motion equation of the known motor is: Set the air pressure error expression: e=P * -p (6) w r =k e (7) Combined with the above formula, we can get the derivative of S: Among them, T e is the output torque, T l is the load torque, J is the moment of inertia, P * is the given air pressure, p is the actual air pressure, k and C are constants, and e is the difference between the given air pressure and the actual air pressure; Set the sliding mode control rate to: Where: S is the switching function, ξ and k2 are constants, Combining the above equations, we can get the expression of output torque, that is, the output of the sliding mode controller is:

2. The wearable flexible knee joint assist suit according to claim 1, characterized in that: The wearable flexible knee joint assist suit further comprises: A shoulder strap, used for a user to carry the portable control system on both shoulders; A waist fixing belt, used for fixing the portable control system on the user's waist; Air pipe A, which is used to deliver the air pressure of the portable control system to the left leg wearing component of the power-assisting suit; Air pipe B is used to deliver the air pressure of the portable control system to the right leg wearing component of the power-assisting suit.

3. The wearable flexible knee joint assist suit according to claim 1, characterized in that: The wraparound kneepad includes a textured side and a smooth side; The fur side is located on the outside of the left leg wearing component of the power-assist suit and the right leg wearing component of the power-assist suit; The smooth side is located on the inner side of the left leg wearing component of the power-assisting suit and the right leg wearing component of the power-assisting suit.

4. The wearable flexible knee joint assist suit according to claim 1, characterized in that: The attitude reference system component can detect the rotation angles of the left and right thighs and calves in the sagittal plane in real time, and can also calculate the knee joint angle by taking the difference between the rotation angles of the thigh and calf on the same side, and feed it back to the controller to provide the portable control system with the user's gait and movement pattern data.

5. The wearable flexible knee joint assist suit according to claim 1, characterized in that: The TPU positive pressure actuator is made of TPU fabric material. Under the action of air pressure, it can rotate from a bent state at any angle to a straight state, generating rotational motion and also outputting torque to the outside. The TPU positive pressure driver is sewn to the fleece side of the wraparound kneepad with the Y-axis of the wraparound kneepad as the axis of symmetry. It can accept positive pressure loading and unloading, and can provide pressure force from the back of the thigh and calf, as well as the knee pit side in the sagittal plane of the human body, providing the knee joint with a torque for extension within the range of 0°-180°, thereby assisting the extension of the knee joints of the left and right legs.

6. The wearable flexible knee joint assist suit according to claim 1, characterized in that: The Velcro A is sewn on the wraparound kneepad to fix and adjust the position of the heading reference system component, so that the heading reference system component is located in the coronal plane of the human body when the left leg wearing component of the power-assist suit and the right leg wearing component of the power-assist suit are worn; The Velcro B is sewn to one end of the wraparound knee pad and fastened with the fleece surface on the outer side of the wraparound knee pad, and is used to fix the left leg wearing component and the right leg wearing component of the power-assist suit at the corresponding positions of the user's knee joint and to adjust the tightness.

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