Powered knee exoskeleton system

Abstract

The invention relates to an exoskeleton system to assist in the gait rehabilitation and assistance process of a patient. The system comprises a lower leg segment, a thigh segment, a pair of powered knee joints connecting the lower leg segment and the thigh segment for the left leg and the right leg, respectively. A pair of hip joints connects a waist segment with the thigh segment and a pair of foot segments connects the lower leg segment. A system controller is adapted to process angular velocity sensor readings and to control the operation of the powered knee joints based on the angular velocity sensor readings. The system controller is further adapted to detect a hip thrust gesture of the user by detecting an increase in forward velocity of the hip joints in the direction of walking, which hip thrust gesture indicates the intention of the user to initiate a forward step. The invention provides the user with an intuitive gait experience that is very similar to natural walking.

Description

Technical Field

[0001] This invention relates to an exoskeleton system for assisting patients with spinal cord injury (SCI) who still retain some motor function at the hip in the process of walking rehabilitation and support.

[0002] The purpose of this invention is to provide an exoskeleton system that provides users with an intuitive gait experience very similar to natural walking, without requiring the execution of unnatural postures.

[0003] Another object of the present invention is to provide an exoskeleton system that reduces undesirable hip joint movements (i.e., abduction-adduction and internal-external rotation), thereby increasing walking speed and stride length, reducing pelvic tilt, and improving upper body posture (i.e., reducing trunk tilt).

[0004] Another object of the present invention is to provide an exoskeleton system that is lightweight and can be easily attached to a patient and can be easily transported and stored. Background Technology

[0005] The World Health Organization estimates the global incidence of spinal cord injury (SCI) at 40 to 80 new cases per million people annually, which translates to 250,000 to 500,000 cases worldwide each year. Inability to stand and walk is one of the main consequences of SCI, leading to loss of independent mobility and limiting community participation and integration. Therefore, reports indicate that gait rehabilitation after SCI is a high priority for patients, regardless of their age, the time elapsed since the injury, or the severity of the injury.

[0006] Regain of walking has been identified as one of the highest priorities for patients with SCI; however, reports indicate that the possible level of recovery depends on the extent of the neurological damage and whether the injury is complete or incomplete. In recent years, technology has evolved into an important component of exercise therapy programs. One of the most significant technological advancements is the creation of robotic exoskeletons, designed to provide patients with the ability to perform repetitive motor tasks with minimal physical strain on therapists. Extensive repetition is one of the key principles supporting motor learning in individuals with incomplete SCI to restore walking function.

[0007] A robotic exoskeleton is a device placed on the human body to assist the user in performing specific movements. Typically, robotic exoskeletons are equipped with sensors to measure variables that will help them make decisions and perform tasks at specific moments. Then, based on the movements that the exoskeleton aims to reproduce, actuators placed in specific locations translate the decisions made into actual movements and forces.

[0008] In particular, wearable lower limb exoskeletons are emerging as a promising solution for restoring mobility after SCI, due to the active participation required to promote physical activity and their potential as assistive devices in the community.

[0009] A small number of exoskeletons have been produced in the past few years and are now certified for use in hospitals around the world, while many other exoskeletons are either in their early stages of development or have not yet been fully certified for large-scale use. These exoskeletons vary significantly in their weight, size, corrective design, and activation methods.

[0010] Typically, exoskeletons require users to perform weight transfers or unnatural posture cues to initiate a step. Furthermore, a lack of hip control leads to excessive hip external rotation, resulting in unbalanced and unwanted leg movements that can ultimately cause injury or falls.

[0011] Another significant limitation of commercially available solutions designed to support patients with severe paralysis is their weight and bulkiness, which limits independent donning / removal, user acceptance, usability, and transportability.

[0012] International PCT application WO2018 / 073252A1 discloses a system for assisting walking in spinal cord injury patients who retain hip flexion capability. The system includes a separate left orthosis and a separate right orthosis. Each orthosis includes an angle actuator for each knee, multiple sensors, and a control system that determines when to flex or extend the knee based on a walking cycle and sensor data readings. The system does not include a lumbar or hip segment connecting the left and right orthosis.

[0013] PCT Publication WO2013 / 188868A1 describes an exoskeleton for applying force to at least one lower limb of a user, comprising: a hip segment; a thigh segment connected to the hip segment via a power joint; a plurality of sensors associated with the lower limb; and a control system.

[0014] PCT Publication WO2016 / 089466A2 relates to systems and methods for providing assistance for human movement, including hip and ankle movements, wherein sensor feedback is used to determine an appropriate profile for actuating a wearable robotic system to deliver desired joint movement assistance. Summary of the Invention

[0015] The present invention is defined in the appended independent claims and satisfactorily addresses the shortcomings of the prior art by providing a bilateral robotic exoskeleton system for assisting patients with spinal cord injury (SCI) in the process of walking rehabilitation and assistance, provided that the patient retains some motor function in the hip, so that the system assists the patient in performing common movements that the patient may find difficult to perform, thereby providing an intuitive gait experience very similar to natural walking.

[0016] More specifically, one aspect of the invention relates to an exoskeleton system comprising: a lumbar segment, a pair of lower leg segments, and a pair of thigh segments, adapted for a patient to wear on the lumbar region, the lower leg portion of the leg, and the thigh portion, respectively.

[0017] The lumbar segment, which connects to the thigh segment, reduces unwanted hip rotation and improves walking performance in patients with SCI.

[0018] The system also includes a pair of powered knee joints or joints connecting the lower leg segment and the thigh segment respectively, to generate flexion and extension movements between the lower leg segment and the thigh segment. Preferably, the powered knee joints are adapted to obtain readings of the flexion angle between the lower leg segment and the thigh segment to which they are connected.

[0019] Additionally, the system includes a pair of hip joints connecting the lumbar segment and the thigh segment. These hip joints can be passive or active joints. In a preferred embodiment of the invention, the pair of hip joints are passive joints, allowing free flexion and extension relative movement between the thigh and lumbar segments while restricting other hip degrees of freedom.

[0020] The system also includes a pair of plantar segments that are connected to the lower leg segments via passive or fixed joints that constrain the ankle joint to keep it fixed in its anatomical configuration.

[0021] The aforementioned structure of the exoskeleton system allows for hip flexion and extension but restricts hip abduction-adduction and internal-external rotation, thereby improving gait performance, walking speed, and stride length, reducing pelvic tilt, and improving upper body posture (i.e., reducing trunk tilt), while also promoting neuroplastic processes.

[0022] The system also includes a pair of sensors arranged to measure the angular velocity of each thigh segment, and a system controller adapted to process the angular velocity sensor readings and to control the operation of the powered knee joint based on the angular velocity sensor readings.

[0023] According to the invention, the system controller is also adapted to detect the hip thrust posture that indicates the user's intention to initiate a forward step by detecting an increase in the forward velocity of the hip joint in the walking direction.

[0024] The system controller is also adapted to operate the corresponding dynamic knee joint to execute a knee flexion-extension trajectory when an increase in the velocity of the corresponding hip joint is detected, so as to swing the user's leg forward to perform a step.

[0025] In addition, the system controller is adapted to operate the powered knee joint to keep the user's leg straight when it detects that the foot is in contact with the ground.

[0026] Preferably, the system controller is adapted to detect when the difference between the compared values ​​exceeds a predefined threshold by detecting a local minimum of the thigh segment angular velocity and comparing the detected local minimum with a subsequently measured angular velocity value, in order to determine an increase in hip joint velocity.

[0027] Therefore, the technical effect and advantage of this invention is that it can predict the user's intention to initiate walking steps without requiring the user to perform unnatural postures. This detection of the user's intention to initiate steps independently and seamlessly at each step allows the user to feel that he / she has complete control over the exoskeleton while walking.

[0028] Furthermore, the system can assist patients in movements such as sitting to standing, standing, walking, and standing to sitting. The exoskeleton system of this invention is intended for use in rehabilitation facilities as a walking aid and for performing walking functions under the supervision of a trained therapist.

[0029] Preferably, the system includes a right button and a left button for the therapist to manually instruct the system when to initiate the right knee flexion-extension trajectory and the left knee flexion-extension trajectory, thereby allowing the user's leg to swing forward to perform a step. The system is also adapted to store the moments when the therapist instructs the initiation of the right knee extension trajectory and the left knee extension trajectory.

[0030] In addition, the system controller is also adapted to perform the calibration process by changing the predefined angular velocity threshold based on manual activation of the left and right buttons and readings of the angular velocity of the thigh or calf segments, so as to personalize the detection of hip thrust posture for each user, and make the timing used to initiate the knee flexion-extension trajectory substantially match the timing indicated by the therapist.

[0031] Furthermore, the system controller is further adapted to perform safety controls to initiate or prohibit the operation of the powered knee joint used to swing the user's leg, and wherein the system controller is further adapted to calculate the difference between the angles of the two thigh segments relative to the vertical, such that when the difference is below a predefined safety threshold, the system controller prohibits the operation of the powered knee joint used to swing the user's leg forward.

[0032] The system controller is further adapted to calculate the difference between the angular orientation of the right lower leg segment and the left lower leg segment as the sum of the angular orientation of each thigh segment and the flexion of the knee.

[0033] In addition, the system controller is adapted to disable the operation of the powered knee joint used to swing the user's leg forward when either of the powered knee joints is performing a stepping motion.

[0034] In addition, the system controller is also adapted to initiate the operation of the powered knee joint to swing the user's leg forward when the difference between the angular orientations of the lower leg segments exceeds a predefined safety threshold and exceeds a predefined time.

[0035] In addition to the angular velocity sensor, the system also includes an orientation sensor that is arranged to measure the angle of each thigh segment relative to the vertical direction perpendicular to the ground.

[0036] The system includes at least one inertial measurement unit (IMU) enclosed within the thigh segment and oriented longitudinally (i.e., in the femoral direction of the thigh segment) for measuring the acceleration, angular velocity, and absolute orientation angle of the thigh segment.

[0037] Each IMU unit has nine degrees of freedom motion sensors, each with a 3-axis gyroscope, a 3-axis accelerometer, and a 3-axis magnetometer, used to measure the orientation and acceleration of each leg, generating absolute orientation, angular velocity, and linear acceleration readings.

[0038] In a preferred embodiment, the exoskeleton is embodied as a modular device. Specifically, the system includes five connectable modules: a lumbar module comprising a lumbar segment and passive free joints connecting to both ends of the lumbar segment; left and right foot segments; and left and right leg modules, each comprising a lower leg segment, a thigh module, and a powered knee joint. It also exhibits a modular design to facilitate transport, storage in a carrying case, and the processes of donning and doffing.

[0039] Therefore, unlike existing exoskeletons that use four or six motors for operation, according to the present invention, only two motors are located at the knee and other movements are preferably passively restricted, enabling patients with complete paraplegia (no motor function below the hip) to walk again.

[0040] Using only two actuators in the knee, the system of this invention helps paraplegic patients stand and walk by maximizing user participation in walking through promoting preserved motor function and actuation only in the knee joint, without aiding unnecessary movement. Knee flexion allows for hip reduction during the swing phase, which reduces oscillations of the center of mass and improves the energy efficiency of the gait. Attached Figure Description

[0041] Preferred embodiments of the present invention are described below with reference to the accompanying drawings, in which:

[0042] Figure 1A preferred embodiment of the exoskeleton system of the present invention in a standing posture is shown in perspective view.

[0043] Figure 2 shows two perspective views of the exoskeleton in two different walking postures, as shown in Figures A and B.

[0044] Figure 3 shows two front views of the exoskeleton: Figure A is the front view and Figure B is the rear view.

[0045] Figure 4 Another perspective view of the exoskeleton used to assist patients in walking is shown.

[0046] Figure 5 The modular structure of the exoskeleton is shown in perspective.

[0047] Figure 6 shows two perspective views of the waist module.

[0048] Figure 7 shows two graphs corresponding to a healthy gait during the three-step time period, where Figure A shows lower leg segment flexion during walking, and Figure B shows the corresponding lower leg segment velocity. Lower leg flexion refers to the angle of the lower leg segment relative to the vertical. The units are irrelevant, but in the context, a positive value is equivalent to the heel pointing backward. Toe-off events are labeled for each step.

[0049] Figure 8 shows two graphs corresponding to the SCI gait using the exoskeleton of the present invention during the three-step time period and corresponding to the graphs in Figure 7. Similar to Figure 7, Figure A shows lower leg segment flexion during walking, while Figure B shows the corresponding lower leg segment velocity. Lower leg flexion refers to the angle that the lower leg segment has relative to the vertical. The unit is irrelevant; in the context, positive corresponds to heel pointing backward. Toe-off events are marked for each step.

[0050] Figure 9 shows the corresponding steps in Figure A. Figure 7B A magnified view of a portion of the image. Figure 9B The difference between the "depth" value and the "significance" value is shown.

[0051] Figure 10 A flowchart of the safety control process is shown. Detailed Implementation

[0052] Figures 1 to 4 An exemplary embodiment of the exoskeleton system (1) of the present invention is shown, comprising a pair of lower leg segments (2, 2′), a pair of thigh segments (3, 3′), and a pair of powered knee joints (4, 4′) connecting the lower leg segments (2, 2′) and the thigh segments (3, 3′) respectively, to generate controlled flexion and extension movements between the lower leg segments (2, 2′) and the thigh segments (3, 3′) for the patient's left and right legs.

[0053] Each powered knee joint (4, 4') includes an electric motor (not shown), which is associated with a gear mechanism (not shown) to increase the motor's torque. The electric motor and gear mechanism are enclosed within a cylindrical housing (8, 8').

[0054] The lower leg segment (2, 2′) and the thigh segment (3, 3′) are constructed as straight and flat rigid bodies, made of lightweight materials such as aluminum, carbon fiber, and / or hard plastics. Figure 3A , Figure 3B As shown, the exoskeleton has a very thin and lightweight construction, which contributes to its portability and usability, while also making it easy to transfer patients from wheelchairs. Specifically, as... Figure 3A , Figure 3B As shown, the lower leg segment and the thigh segment are coplanar, meaning they move relative to each other on the same plane. The exoskeleton has no backpack or upper body components, and its compact design allows it to be worn while seated in a standard wheelchair.

[0055] System (1) also includes a lumbar segment (5) with a generally U-shaped structure, and is anatomically adapted to connect at the hip and lumbar regions of the patient, as shown in Figure 3 and Figure 4 As shown. Figure 4 As shown in more detail, the waist segment (5) is also constructed as a flat body made of lightweight material and includes a strap (17) or belt for securely attaching it to the user's waist area.

[0056] Similarly, each thigh segment (3, 3′) is equipped with a thigh support (18, 18′) with a thigh strap (21, 21′), and each calf segment (2, 2′) is equipped with a calf support (19, 19′) with a calf strap (2, 2′), for supporting and attaching the thigh segment and calf segment to the corresponding parts of the user's left and right legs, respectively.

[0057] The system also includes a pair of hip joints (6, 6′) that connect the ends of the lumbar segment (5) to the thigh segment (3, 3′). In this exemplary embodiment, the pair of hip joints (6, 6′) are passive joints that allow free flexion and extension relative movement between the thigh segment (3, 3′) and the lumbar segment (5). However, in other practical embodiments, the hip joints (6, 6′) are embodied as active joints.

[0058] In addition, in this preferred embodiment, a pair of plantar segments (7, 7′) are connected to the lower leg segments (2, 2′) by corresponding fixation joints (9, 9′), which constrain the ankle joint to keep it fixed in its anatomical structure, thereby preventing the user's ankle movement.

[0059] The position of the plantar segments (7, 7′) relative to the lower leg segments (2, 2′) is longitudinally adjustable. To this end, each plantar segment (7, 7′) includes a rod (10, 10′) that is telescopically connected to the corresponding lower leg segment (2, 2′) and is provided with a quick-release locking pin to secure the plantar segment to the corresponding lower leg segment in the desired position.

[0060] The hip width, thigh length and depth, calf length and depth, and heel stop depth can be easily adjusted without any external tools using quick-release locking pins, and the exoskeleton is designed to be used by people weighing up to 100kg and between 150cm and 190cm in height.

[0061] like Figure 2B , Figure 6A and Figure 6B As more clearly shown, the lumbar segment (5) has a housing (15) that encloses the battery components and the electronic control unit (ECU), and preferably also encloses the Wi-Fi and Bluetooth communication modules. Additionally, the housing (15) is configured to function as a therapist's hand holder to help the user maintain balance, such as... Figure 6B As shown.

[0062] A pair of buttons (16) are located in the housing (15) and associated with the electronic control unit (ECU), allowing the therapist to manually instruct the system when to swing the user's left and right legs forward to perform a step, enabling the system controller to perform the previously explained calibration procedure. In addition to manually triggering the step, the buttons (16) can also be used to trigger other transitions, such as standing and sitting.

[0063] While standing, the actuators of the powered knee joint apply the necessary torque to keep the user's leg straight. To detect the user's intention to move forward, the built-in ECU in the lumbar segment (5) receives motion data caused by hip movement from IMU sensors placed in the thigh segment (3, 3'), analyzes the data, and identifies the moment when the knee flexion-extension cycle must be triggered to swing the leg forward, thus mimicking the trajectory of a natural gait. Auditory feedback and visual cues from LEDs on the lumbar segment notify the therapist and user of the system status and operational status.

[0064] like Figure 2A , Figure 2B As shown, the IMU unit (20, 20′) is preferably integrated within the thigh segment (3, 3′), directly above the dynamic knee joint (4, 4′). Alternatively, the IMU unit (20, 20′) is placed at the lower leg segment (2, 2′), directly below the dynamic knee joint (4, 4′).

[0065] like Figure 4As shown, the exoskeleton is used in conjunction with a cane, crutch, or walking aid for stability, and if needed, the therapist can help the user maintain balance by holding the shell (15) with both hands, such as Figure 6B As shown, a pair of buttons (16) are positioned such that the therapist's fingers can reach the buttons without having to hold the housing (15) while moving his hand.

[0066] like Figure 5 As shown, the exoskeleton system (1) is constructed as a modular device comprising five connectable modules: a lumbar module (11) formed by a lumbar segment (5) and passive free joints (6, 6′), each of which is connected to the end of the lumbar segment (5); a left leg module and a right leg module (12, 12′), each of which includes a thigh segment (3, 3′), a lower leg segment (2, 2′) and a corresponding powered knee joint (4, 4′); and finally, a foot module (13, 13′), which includes a foot segment (7, 7′) and a bar (10, 10′).

[0067] In order to connect the waist module (11) with the left leg module and the right leg module (12, 12'), the system (1) is equipped with quick-connect devices (14, 14') for mechanically and electrically connecting the modules together to connect the battery and ECU to the IMU unit located in the thigh segment (3, 3') and the electric motor in the knee joint (4, 4').

[0068] To use the exoskeleton, modules are first individually attached to the corresponding body parts, and then they are connected together. This modularity provides unique usability by significantly reducing the time spent putting on and taking off the device. This feature, along with the compact and slim structure positioned closest to the user's body, allows the exoskeleton to be put on and taken off directly from the wheelchair, avoiding an unnecessary transition to the chair. It also provides ease of handling, transporting, and storing in a small carrying case.

[0069] Preferably, the housing (15) also encloses a Wi-Fi and Bluetooth communication module, which allows the therapist to configure (appropriately adapt to the user, display system status), operate (transition between operating states, change gait parameters (e.g., knee flexion or swing phase time)) and monitor (use in real time, track user progress, record treatment data) the exoskeleton during the treatment process via a mobile phone application.

[0070] The system includes an add-on for advanced users: a remote control (not shown) that can be attached to a cane, crutch, or walker to allow users to independently switch between operating modes. The remote control communicates wirelessly with the exoskeleton via Bluetooth and provides status feedback for the visual and auditory systems. Therefore, users can always stand, walk, and sit independently under the supervision of a therapist.

[0071] Figures 7 and 8 illustrate the control process executed by the system controller. As these figures show, around the toe-off event in each step, i.e., when the user lifts their foot off the ground, the angular velocity of the lower leg rises from a local minimum considered to be “depth” to a maximum considered to be “significance”.

[0072] In this invention, it has been found that detecting the two key points “depth” and “salience” is equivalent to detecting a forward “hip thrust” when an SCI patient uses a bilateral exoskeleton, and that the detected “hip thrust” is considered to be the posture in which the patient initiates each step.

[0073] When a user (especially a patient with SCI) takes a step forward using a walking aid, it is achieved by first pushing the hip forward before lifting the foot off the ground. Therefore, detecting “hip thrust” is equivalent to detecting the patient’s intention to initiate a step. “Hip thrust” can be defined as a sudden increase in the forward velocity of the hip joint (in the direction of walking) during the double-stance phase of walking.

[0074] Figure 9A A magnified view corresponding to one step of lower leg flexion is shown, indicating the "depth" and "salience" values, and Figure 9B The difference between the "depth" and "significance" values ​​is shown. The core calculation process performed by the system controller is as follows: First, the minimum angular velocity is measured and stored as the "depth" value. Second, the stored "depth" value is compared with the actual measured angular velocity. When the angular velocity decreases, the two will be equal, but once a local minimum is found, the actual velocity will increase. Once the difference between the actual velocity and depth exceeds a predefined threshold (significance), "hip thrust" has been detected, and a stepping motion should be triggered to operate the corresponding dynamic knee joint to swing the user's leg forward.

[0075] Therefore, the function to be minimized in the core computation process needs to be:

[0076] - A variable that stores the depth;

[0077] - An adjustable parameter, significance;

[0078] - Readings from the angular velocity sensor.

[0079] Above this core computing process, the system controller is adapted to implement safety controls to enable or disable the execution of the core computing process, thereby enabling or disabling the operation of the powered knee joint.

[0080] In this safety control, the system controller calculates the difference between the angles of the two thigh segments relative to the vertical, such that when the difference is below a predefined safety threshold, the system controller prohibits the operation of the powered knee joint used to swing the user's leg forward.

[0081] The core calculation is reset whenever a step is completed or when the thigh angle becomes negative. This ensures that the swing portion of the step is ignored and increases robustness at the start of walking.

[0082] Unless the longitudinal leg separation exceeds a predefined threshold, safety controls use the thigh angle to prevent the algorithm from being executed. This is calculated as the difference in thigh angle relative to the vertical distance. Any angular difference between legs below a given threshold disables the trigger for safety. It also controls when a core reset is required.

[0083] The minimum safety control parameters are as follows:

[0084] - Measure the vertical thigh angle relative to the two supports;

[0085] - One parameter that controls the minimum interval of the starter core;

[0086] - One parameter that controls straight-leg knee flexion.

[0087] This is set up as a series of IF statements preceding the core functionality, which disables the core under the following conditions:

[0088] - If the spacing between legs is less than a predefined threshold, then disable the core;

[0089] - If the thigh angle becomes negative (heel pointing forward), the core is reset, clearing its memory;

[0090] - If the knee flexion angle is different from the predefined straight-leg knee flexion, the core is disabled.

[0091] The entire process requires:

[0092] - Measure the angular velocity of each thigh;

[0093] - Measure the vertical angle relative to each thigh;

[0094] - A variable used to store depth.

[0095] And adjust as follows:

[0096] -1 primary parameter, significance;

[0097] -2 minor parameters:

[0098] - Minimum leg spacing

[0099] - Straight leg with knee bent.

[0100] Secondary parameters are defined so that they can be set at the start of the session and do not require much change. However, core parameters typically need to be adjusted to the patient's current state and will change as the user becomes comfortable with the device and recovery progresses.

[0101] At a higher level, the algorithm executes and runs at each time interval. Figure 10 The test in the flowchart. Each box in the flowchart represents a function that is called and modifies the state or returns a condition indicating success or failure.

[0102] The exoskeleton system automatically adapts to each user, running a calibration process that monitors the measured data and adjusts parameters to appropriate values ​​for functionality. Calibration can run in parallel with or serially with data acquisition. Parallel or "real-time calibration" is performed alongside the core process, adjusting parameters after each step.

[0103] In a preferred embodiment, the calibration process is performed serially, with the calibration optimizing parameters after a set of steps to avoid interfering with the user of the exoskeleton when used directly.

[0104] In order to initiate the calibration process, a second user (usually a therapist) manually triggers the step using the button (16) on the housing (15).

[0105] The workflow is as follows:

[0106] -Activate calibration;

[0107] - The exoskeleton begins storing data;

[0108] - Users and therapists use manual mode to execute the maximum possible steps;

[0109] - Exoskeleton processing data;

[0110] - Adjust parameters.

[0111] This workflow allows for independent measurement of data. It assumes the therapist knows the correct timing to trigger the step, and therefore the walking algorithm does not affect the data used for calibration. This information can then be used to recommend parameters that will result in a gait pattern similar to the therapist's recommended pattern.

[0112] The measured data is as follows:

[0113] -time;

[0114] -L / R thigh angular velocity;

[0115] - Differences in leg angles;

[0116] -L / R stepping state (1 when the knee is flexed or extended, 0 otherwise).

[0117] The calibration process mainly depends on the data processing pipeline, which consists of several steps to extract relevant points from the data to calculate parameters.

[0118] 1. Filter: Filters the L / R angular velocity to smooth out noise and unexpected peaks;

[0119] 2. Pruning: Shorten the data to include only cycles with consistent pace;

[0120] 3. Minimum leg spacing estimation;

[0121] 4. Significance estimation.

[0122] In step 3, the minimum leg interval estimate recommends a minimum leg interval value that ensures that steps triggered by the therapist are allowed. It achieves this by storing the leg interval at each trigger.

[0123] The recommended value will be the mean minus two standard deviations. This ensures that the trigger step follows 95% of the theoretical distribution. This value is then clamped to a default minimum to exclude extremely small values ​​that should not be allowed for safety reasons.

[0124] In step 4, the significance estimation recommends significance values ​​that will trigger most steps in the data distribution. It does this by first detecting when a step is triggered, and then measuring the absolute significance and absolute depth backward.

[0125] Successful steps are determined by classifying the minimum values ​​of thigh angular velocity. A step is considered successful if it produces a minimum value below 100 degrees per second (the three lowest minimum values ​​in Figure 8).

[0126] For each peak, an iteration is performed to find significance (Figure 8). If significance is found, the iteration continues to find the next minimum, i.e., the depth. When both values ​​are found, the recommended significance is stored. Figure 9B ).

[0127] The recommended value is the average significance minus two standard deviations. This ensures 95% of the theoretical distribution of the trigger step. This value is then clamped to a default minimum to exclude extremely small values ​​that should not be allowed for safety reasons.

[0128] These recommended values ​​are stored in each individual user's walking profile. This process allows the gait triggering algorithm to be personalized for each individual, seamlessly detecting the user's intention to initiate each step by interpreting the minimum movements generated by the user. This allows users to skip trial and error and focus on therapy, concentrating their efforts on generating healthy gait patterns.

[0129] Other preferred embodiments of the invention are described in the appended dependent claims and in various combinations thereof.

Claims

1. A powered knee exoskeleton system (1), comprising: A pair of lower leg segments (2, 2'); A pair of thigh segments (3, 3'); A pair of dynamic knee joints (4, 4′) connect the lower leg segment (2, 2′) and the thigh segment (3, 3′) respectively to produce flexion and extension movements between the lower leg segment (2, 2′) and the thigh segment (3, 3′); Lumbar segment (5); A pair of hip joints (6, 6′) connect the lumbar segment (5) to the thigh segment (3, 3′); A pair of plantar segments (7, 7′) are respectively connected to the lower leg segments (2, 2′); At least one pair of sensors adapted to measure or calculate the angular velocity of each of the thigh segments (3, 3′) or the lower leg segments (2, 2′); A system controller adapted to process angular velocity sensor readings and to control the operation of the powered knee joint (4, 4') based on the angular velocity of the sensor readings. The system controller is further adapted to detect the user's hip thrust posture by detecting an increase in the forward velocity of the hip joint in the walking direction, the hip thrust posture indicating the user's intention to initiate a forward step. The system controller is adapted to determine the increase in the forward velocity of the hip joint in the walking direction (6, 6′) by detecting a local minimum of the angular velocity of the thigh segment or the lower leg segment, comparing the detected local minimum with a subsequently measured angular velocity value to detect when the difference between the compared values ​​is higher than a predefined threshold, wherein the core calculation used to determine the increase in the forward velocity is reset each time the thigh or lower leg angle becomes negative.

2. The system according to claim 1, wherein, The system controller is also adapted to operate the corresponding dynamic knee joints (4, 4') to execute a knee flexion-extension trajectory when an increase in the speed of the hip joints (6, 6') has been detected, thereby allowing the user's leg to swing forward to perform a step.

3. The system of claim 1, comprising a right button and a left button (16) for the therapist to manually instruct the system when to initiate a right knee flexion-extension trajectory and a left knee flexion-extension trajectory, thereby allowing the user's leg to swing forward to perform a step, and wherein, The system is also adapted to store the moments when the therapist instructs the initiation of the right knee extension trajectory and the left knee extension trajectory.

4. The system according to claim 3, wherein, The system controller is also adapted to perform a calibration process by changing a predefined angular velocity threshold based on manual activation of the left and right buttons (16) and readings of the angular velocities of the thigh segment or the lower leg segment, in order to personalize the detection of the hip thrust posture for each user, such that the timing used to initiate the knee flexion-extension trajectory substantially matches the timing indicated by the therapist.

5. The system of claim 1 further includes an orientation sensor arranged to measure the angle of each thigh segment or calf segment relative to a vertical axis perpendicular to the ground.

6. The system according to claim 5, further comprising at least one inertial measurement unit (IMU) enclosed within the thigh segment (3, 3') for measuring the acceleration, angular velocity and absolute orientation angle of the thigh segment (3, 3').

7. The system according to claim 5, wherein, The system controller is also adapted to perform safety controls to initiate or disable the operation of the powered knee joint (4, 4′) used to swing the user's leg, and wherein the system controller is also adapted to calculate the difference between the angles of the two thigh segments (3, 3′) or lower leg segments (2, 2′) relative to the vertical, such that the system controller initiates the operation of the powered knee joint (4, 4′) to swing the user's leg forward only when the difference is higher than a predefined safety threshold and exceeds a predefined time.

8. The system according to claim 7, wherein, The predefined time can be zero.

9. The system according to claim 1, wherein, The dynamic knee joint (4, 4') is adapted to obtain readings of the flexion angle between the connected lower leg segment and the thigh segment.

10. The system according to claim 9, wherein, The system controller is also adapted to calculate the difference between the angular orientations of the two lower leg segments (2, 2′) as the sum of the angular orientation of each thigh segment and the flexion of the powered knee joint.

11. The system according to claim 9, wherein, The system controller is also adapted to disable the operation of the powered knee joints (4, 4') used to swing the user's leg forward when any of the powered knee joints (4, 4') is performing a stepping motion.

12. The system according to claim 1, wherein, The pair of hip joints (6, 6') are either passive or active joints.

13. The system according to claim 12, wherein, The pair of hip joints (6, 6') are passive joints that allow free flexion and extension relative movement between the thigh segment (3, 3') and the lumbar segment (5), and restrict hip abduction-adduction and hip internal and external rotation.

14. The system according to claim 1, wherein, The pair of plantar segments (7, 7′) are connected to the lower leg segments (2, 2′) via passive joints or fixed joints, respectively, the fixed joints constraining the ankle joint to remain fixed in its anatomical structure to prevent ankle movement by the user.

15. The system according to claim 1, wherein, The position of the plantar segments (7, 7′) relative to the lower leg segments (2, 2′) is longitudinally adjustable, the lengths of the thigh segments (3, 3′) and the lower leg segments (2, 2′) and the width of the lumbar segment are telescopically adjustable, and / or wherein, The position can be manually changed each time by quickly releasing the locking pin.

16. The system according to claim 1, wherein, The system controller is adapted to operate the powered knee joint (4, 4') to keep the user's leg straight when contact with the ground is detected.

17. The system according to any one of claims 1 to 12 further comprises five connectable modules: a lumbar module (11) formed by the lumbar segment (5) and passive free joints (6, 6′), each passive free joint being connected to an end of the lumbar segment (5); a left leg module and a right leg module (12, 12′), each of the left leg module and the right leg module comprising a thigh segment (3, 3′), a lower leg segment (2, 2′) and a powered knee joint (4, 4′); and a left foot module and a right foot module (13, 13′), each of the left foot module and the right foot module comprising a foot segment (7, 7′) and a bar (10, 10′).

18. The system according to claim 17, wherein, The system also includes a quick-connect device for connecting the modules together, wherein the quick-connect device for connecting the waist module to the left and right modules includes an electrical connection.

19. The system according to claim 17, wherein, The waist segment has a housing (15) containing a battery component and an electronic control unit (ECU), both of which are enclosed within the housing (15).

20. The system according to claim 19, wherein, The housing (15) has a pair of hand holders for the therapist to help the user maintain balance, and a button (16) associated with the electronic control unit (ECU).

21. The system according to claim 19, wherein, The waist module (11) includes a belt or strap (17) for attaching the waist module (11) to the user's waist area.

Images