Method for controlling an orthopedic joint device

Abstract

The invention relates to a method for controlling an orthopedic knee joint device comprising: an upper part (10), a lower part (20) and a foot part (25) fastened thereto, at least the upper part (10) and the lower part (20) being mounted on one another so as to be pivotable about a pivot axis (15); an actuator (30) coupled to the upper portion (10) and the lower portion (20) and affecting the pivoting movement. The actuator (30) is coupled to a control device (40) that is coupled to at least one sensor (50) and activates, deactivates, or modulates the actuator (30) based on a sensor value of the at least one sensor (50). Displacement of the foot (25) is detected by detecting and analyzing linear accelerations and / or positional changes of the upper portion (10), the lower portion (20) and / or the foot (25), and the buckling resistance is modified relative to the initial state before displacement during the wobble period or during the load response of the foot.

Description

TECHNICAL FIELD

[0001] The invention relates to a method for controlling an orthopedic knee joint device having an upper part and a lower part and a foot fixed on the lower part, wherein the upper part and the lower part are pivotably supported on each other about a pivot axis, an actuator coupled with the upper part and the lower part and influencing a pivoting movement, wherein the actuator is coupled with a control device, which is coupled with at least one sensor and activates, deactivates or modulates the actuator based on a sensor value of the at least one sensor. BACKGROUND

[0002] Orthopedic joint devices, in particular orthoses, exoskeletons or prostheses, have an upper part and a lower part which is hingedly supported thereon. For orthoses and exoskeletons, the upper part and the lower part are fixed on a still present limb by means of, for example, a housing, a strap, a belt, a cuff or other fixation means. By means of orthoses and exoskeletons, movements can be guided, pivoting about a joint axis can be limited, pivoting movements can be prevented or relative positions between the limbs can be supported and fixed. For polyaxial joints, the pivot axis is the instantaneous center of rotation, which moves depending on the pivoting movement. Furthermore, orthoses can be equipped with damping devices to dampen the pivoting movement about the joint axis. These damping devices can be equipped with control devices, so that a varying damping in the flexion direction and / or in the extension direction can be provided depending on sensor data. It is also known to assign an energy store to the upper part and / or to the lower part, so that a movement support can be provided by releasing the energy stored in the energy store.

[0003] Prostheses replace missing or no longer present limbs and serve to provide a function as close as possible to the function of a natural limb. Furthermore, prostheses are intended to provide a prosthesis user with an appearance as natural as possible. For example, a prosthesis upper part is formed as a prosthesis socket or a component fixed on a prosthesis socket, wherein the prosthesis socket serves for fixation to a limb or a limb stump. Prosthesis joints, for example prosthesis knee joints, connect an upper part with a lower part, which in turn can have further prosthesis components, for example a lower leg tube or a prosthetic foot.

[0004] In particular in orthoses, exoskeletons and prostheses of the lower limbs, but also of the upper limbs, dampers, in particular hydraulic dampers or other resistance means, are arranged between the upper and lower part, which provide different resistances in different states or movement situations on the basis of sensor data. Such resistance means are usually formed as linear actuators, which provide a defined resistance to the flexion movement and / or the extension movement. The resistance is changed, for example, by changing the position of a valve. When the flow cross section is reduced, the corresponding resistance to the movement increases. Passive dampened, in particular passive hydraulic dampened, prostheses or orthoses are purely dissipative. Here, energy is extracted from the movement of the upper part relative to the lower part, so that very high torques or forces can be generated. At the same time, passive dampening has only a very small resistance in the open state, for example when there is no valve closure or throttle activation. The working range of such orthoses or prostheses is limited, since no energy can be input into the movement to support the movement or actively counteract the movement, or changes from a static state.

[0005] Furthermore, orthoses, exoskeletons and prostheses are known from the prior art which have a motor drive, so-called active orthoses or prostheses, in which the movement is initiated, supported or braked by activating, deactivating or modulating the drive.

[0006] For this purpose, the stored electrical energy from a battery or accumulator is converted into energy in the actuator. The motor drive is likewise used to influence the movement behavior between the orthosis or prosthesis parts, for example to brake the pivoting movement. The motor drive can be operated for this purpose in a braking mode or in a generator configuration.

[0007] Whether a pure passive means such as a damper, a semi-active means such as an accumulator, or a motor drive, influences the movement behavior of the upper and / or lower part and is an actuator which influences the movement state of the upper and / or lower part. The actuator can cause a movement, reverse a movement, support a movement or exert a resistance to a movement. There is also an influence on the movement state of the upper and / or lower part when counteracting a load, maintaining a static state or preventing or resisting a change in the movement state due to external forces. This can occur, for example, when it is intended to maintain a uniform pivoting movement and external forces act in the direction of movement or counter to the direction of movement.

[0008] EP2869792B1 discloses a method for controlling a joint device in lower limb orthotic techniques. The device has an upper portion and a lower portion hinged thereon, with an energy conversion and / or storage device arranged between them. This device converts and / or stores kinetic energy from the relative motion between the upper and lower portions during walking. This energy can be re-provided to the joint to support relative motion, wherein kinetic energy is converted and / or stored within one movement cycle of the joint device and is re-provided as kinetic energy in a controlled and time-delayed manner within the same movement cycle. The conversion rate and / or storage rate of the energy conversion or storage device are inversely proportional to the pivoting speed of the lower leg.

[0009] WO2016 / 169850A1 relates to a method for controlling damping variations in an artificial joint of an orthosis, exoskeleton, or lower limb prosthesis, the artificial joint having a resistance unit between an upper portion and a pivotally interconnected lower portion. The resistance is changed via the resistance unit when a sensor signal from a control device assigned to the adjustment unit activates the adjustment unit. The resistance is changed based on the location and / or length of a tendon or its time derivative.

[0010] WO2016 / 169848A1 also relates to a method for controlling damping variations in an artificial knee joint, wherein flexion resistance is reduced during the swing phase. During walking or standing, a process is detected of at least one load characteristic acting on an orthosis or prosthesis with an artificial knee joint. If a maximum value of the load characteristic process is determined during the standing phase, and a threshold of the load characteristic below that maximum value is subsequently detected, then the flexion damping is reduced to the swing phase damping level during the standing phase.

[0011] Microprocessor-controlled prostheses or orthoses adapt to different activities, environmental conditions, or movement patterns during walking. For example, different control strategies or processes are used for walking on flat ground, descending stairs, and walking downhill. Furthermore, standing and activities involving movement are differentiated. To provide optimal support for the user in different situations, it is necessary, or at least advantageous, to provide appropriate behavior of the orthotic joint device upon initial contact with the limb equipped with the orthosis or prosthesis, such as desired movement resistance, stiffness, or desired joint angle. Summary of the Invention

[0012] Therefore, the objective of this invention is to provide a method for controlling orthopedic knee joint devices, so as to provide optimal settings even under different and varying motion conditions.

[0013] This task is accomplished by a method having the features of the independent claims. Advantageous embodiments and improvements are disclosed in the dependent claims, the specification, and the drawings.

[0014] This invention proposes a method for controlling an orthotic joint device comprising: an upper part, a lower part, and a foot fixed to the lower part, wherein at least the upper part and the lower part are pivotally supported on each other about a pivot axis; an actuator coupled to the upper part and the lower part and influencing pivotal movement, wherein the actuator is coupled to a control device coupled to at least one sensor and activating, deactivating, or modulating the actuator based on sensor values ​​of the at least one sensor. The method is characterized by detecting foot displacement by detecting and evaluating linear acceleration and / or positional changes of the upper part, linear acceleration and / or positional changes of the lower part, and / or linear acceleration and / or positional changes of the foot, and during the swing phase or load response of the foot, flexion resistance is altered relative to the initial state before displacement. The load response is a phase in the gait cycle or walking motion that includes heel strike or initial ground contact and subsequently continues for up to 12% of the gait cycle or motion. Therefore, the load response extends from the start of the standing phase to approximately 25% of the standing phase duration, assuming the standing and swing phases are roughly equal in duration. This method allows the swing phase to be detected via linear acceleration, without prior movement or a movement process released during a previous swing phase. This enables the detection not only of the swing phase itself but also the initiation of preparation for the subsequent standing phase. Preparation for changes in resistance or position can already occur during the swing phase, allowing for resistance alteration or position setting within the orthopedic device's artificial knee joint before foot contact and the load response. For this purpose, actuators are activated, deactivated, or modulated, for example, to reduce resistance against flexion or to adjust joint angles to improve or adapt to the load response.

[0015] In one configuration, the initial state is standing, or a situation different from walking, where the feet are in contact with the ground. This difference from walking includes, for example, sitting, initiating movement (e.g., starting), or withdrawing the feet. When the feet, especially the foot receiving part of a prosthesis or orthosis, are in contact with the ground, the actuator should be configured to recognize the next standing phase as early as possible and adapt to the expected load, regardless of any prior movement or state. Adapting to the expected load is particularly advantageous when standing, i.e., when both feet are on the ground and under load, during the swing phase or at the initial contact after the swing phase.

[0016] In one configuration, foot displacement includes lifting the foot, which is identified in particular by a decrease in the axial force component in the foot and / or lower body, or where a decrease in the axial force component in the foot and / or lower body is at least part of the criterion for lifting or the presence of a swing phase. Alternatively or additionally, the vertical acceleration of the foot and / or lower body can be determined and used as at least part or the sole criterion for lifting or the presence of a swing phase, thereby determining that the foot has been displaced.

[0017] In one configuration, during the shift, the resistance against flexion during the swing phase remains constant during the lifting phase of the foot and / or lower body, and decreases before foot contact with the ground, for example, during the descent phase of the foot. Alternatively or additionally, during the swing phase, the joint angle between the upper and lower body is set before foot contact with the ground to achieve the most favorable orientation of the lower body or foot relative to the upper body and possible ground.

[0018] In one configuration, at least one linear acceleration of the upper, lower, and / or foot portion is determined by at least one sensor. This linear acceleration can be specifically configured as vertical or horizontal acceleration. The corresponding sensor either enables direct acceleration measurement via an inertial sensor or allows determination via, for example, a conversion based on pivoting at known dimensions.

[0019] In one configuration, the linear acceleration of the foot in the walking direction is determined, where positive and / or negative accelerations in the walking direction are used as linear accelerations. Positive acceleration exists in the walking direction when the foot moves forward and accelerates; negative acceleration exists in the walking direction when the toes move forward and backward.

[0020] In one configuration, linear acceleration is measured at the foot, or calculated from the lower linear acceleration combined with the lower angular acceleration. Alternatively, linear acceleration can be calculated from the upper linear acceleration combined with the knee angle and the lower angular acceleration.

[0021] One configuration specifies the detection of ankle torque in the foot and / or lower segment, with a decrease in ankle torque serving as a criterion for the presence of a lift or swing phase. Ankle torque is the resistance to displacement of the foot relative to the lower segment about an axis substantially orthogonal to the sagittal plane, or the resistance that causes pivoting about that axis. A decrease in ankle torque can serve as a criterion, or at least a partial criterion, for the presence of a swing phase, because this decrease occurs at the end of the standing phase, for example, when the unfit side of the patient bears the full body weight and the fitted side is lifted. This occurs at the end of each walk or, for example, when lifting the foot while walking up stairs. If a swing phase is present, it can be assumed that the foot is displaced, and the flexion resistance can or must change relative to the initial state before the displacement. In particular, the lift and manner of foot lifting can be detected by combining vertical acceleration. Foot lifting can also be detected solely by determining the vertical acceleration of the foot, i.e., acceleration opposite to the direction of gravity, and served as a criterion for foot lifting or the presence of a swing phase. Since the foot is typically permanently coupled to the lower body, the standard for reducing axial force on the foot or vertical acceleration of the foot also applies to the lower body accordingly.

[0022] In one configuration of this method, during foot displacement, the resistance against flexion during the swing phase remains constant during the lift phase, i.e., as the foot and / or lower body move upwards against gravity. Before the foot contacts the ground, the resistance against flexion is then reduced, and this reduction still occurs during the swing phase. Alternatively or supplementarily, joint angles are set, where the joint angles can be either the knee joint angles or the foot joint angles relative to the lower body. The foot joint angles can also be set independently of the knee joint angles. Changes in joint angles are independent of changes in flexion resistance during the swing phase or during the foot's load response.

[0023] One configuration specifies that at least one linear acceleration of the upper, lower, and / or foot is determined by at least one sensor. The respective linear accelerations can be determined directly by sensors designed for this purpose; vertical acceleration is measured by a vertical acceleration sensor, and horizontal acceleration by a horizontal acceleration sensor. Alternatively, they can be determined indirectly, for example, by detecting joint angles or changes in joint angles and knowledge of the distance from the relevant point to the rotation axis, combined with, for example, spatial orientation sensors, to determine whether and to what extent the foot is moving horizontally or accelerating in a certain direction. Specifically, the linear acceleration of the foot in the walking direction is determined. If linear acceleration occurs in the walking direction, the foot or foot moves forward, thereby altering the flexion resistance.

[0024] In one configuration, linear acceleration is measured at the foot, or calculated based on the lower linear acceleration combined with the lower angular acceleration, or the upper linear acceleration combined with the knee angle and the lower angular acceleration.

[0025] An extension of this method specifies the detection of ankle joint torque in the foot and / or lower part of the ankle, and uses a decrease in ankle joint torque as a criterion, or partial criterion, for the presence of a lift or swing phase. If the foot is in the air, which may be characteristic of a swing phase, no associated external forces are acting on the foot that could cause pivoting around the ankle joint axis. Therefore, no ankle joint torque is generated relative to the lower part of the foot, and thus a decrease in ankle joint torque can be used as a criterion for the end of the standing phase or the presence of a lift or swing phase.

[0026] One configuration specifies that the knee joint torque of the lower part relative to the upper part about the pivot axis is detected, and the knee joint torque, especially the knee joint torque in the flexion direction, is used as a criterion or partial criterion for the presence of a lift or swing phase.

[0027] Furthermore, the spatial orientation of the upper, lower, and / or foot can be used as a criterion, or partially, for the presence of a lift or swing phase. When the lower part has a backward tilt in space when viewed from the distal end, this state can be used as a criterion, or partially, for the presence of a lift or swing phase. For example, a backward tilt exists at the end of the swing phase and before the foot touches the ground during flat walking. After toe lift and the initial swing phase, the forward tilt of the lower part in space increases. As extension increases after reaching the maximum knee flexion angle, the forward tilt decreases until a vertical orientation in space, and then becomes backward tilted as extension increases. If the lower part is in a backward tilted state, especially in conjunction with the absence of ankle torque, it can be inferred that the swing phase has ended during flat walking, and therefore this can be used as a criterion for the swing phase.

[0028] Conversely, the orientation of the upper, lower, and / or foot in space exceeding a threshold can be used as a criterion for the absence of a lift or swing phase, at least not a swing phase or a situation requiring a change in flexion resistance. Advantageously, sensor values ​​are determined and evaluated in real time to allow for adjustments to individual resistances or factors affecting the movement process during the use of orthotic devices.

[0029] The duration of sensor values ​​exceeding the time window can be used as a criterion for the absence of a lift or swing phase. If the upper, lower, and / or foot remain in the same position for an extended period, it can be assumed that there is no need to change flexion resistance, joint angles, and / or affect upper-to-lower pivotability, and therefore changes only occur, for example, during movements with sufficient speed.

[0030] Flexion resistance can be set during the swing phase or load response to correspond to the flexion resistance at initial contact during flat walking, thus serving as a standard resistance for the load response. A resistance is set after initial heel contact that allows flexion during the stance phase without knee collapse. Attached Figure Description

[0031] Embodiments of the present invention will now be explained in more detail with reference to the accompanying drawings. The same reference numerals denote the same parts. Not all parts are labeled with reference numerals in all figures to avoid affecting clarity. The drawings are as follows.

[0032] Figure 1 A schematic diagram of a prosthetic knee joint is shown.

[0033] Figure 2 The diagram shows the starting step from a standing position.

[0034] Figure 3 This shows the starting stride when walking downhill.

[0035] Figure 4 This indicates the identification of the step initiation.

[0036] Figure 5The process of load, foot position, and lower leg angle is shown.

[0037] Figure 6 This indicates a state change.

[0038] Figure 7 This demonstrates the step initiation process incorporating contextual recognition.

[0039] Figure 8 This shows the adjustment of buckling resistance at start-up.

[0040] Figure 9 Show Figure 8 A variant of .

[0041] Figure 10 This shows the adjustment of effective spring stiffness and damping during start-up.

[0042] Figure 11 Show Figure 10 A variant of .

[0043] Figure 12 This demonstrates the control of degrees of freedom.

[0044] Figure 13 This demonstrates the continuous adaptation of features to the context. Detailed Implementation

[0045] exist Figure 1 The image shows a prosthetic knee joint as part of a prosthesis. This prosthetic knee joint has an upper part 10 and a lower part 20, which are pivotally supported on each other about a pivot axis 15. A prosthetic foot 25 is arranged on the lower part 20 at the distal end 21. Figure 1In the illustrated prosthetic leg embodiment, the upper part 10 is provided or formed with a device for accommodating or securing the prosthetic tube or other means for receiving or fixing the thigh stump to the person. A resistance device 30, acting as a linear hydraulic actuator, is arranged between the upper part 10 and the lower part 20. In the illustrated embodiment, the hydraulic actuator 30 is formed with a hydraulic chamber or cylinder arranged or formed within a housing or body 31. A piston 32 is displaceably mounted in the cylinder. The piston 32 is longitudinally movable along the cylinder and is fixed to a piston rod 33 protruding from the housing or body 31. The piston 32 divides the cylinder into two chambers fluidly connected by hydraulic lines. The body 31 or housing can be pivotally mounted at a fixing point 23 on the lower part 20 to prevent the piston 32 from jamming during pivoting of the upper part 10 relative to the lower part 20. One end of the piston rod 33 opposite to the piston 32 is fixed to the body 31, and in the illustrated embodiment, to an upper fixing point 210 on a cantilever of the upper part 10 for increasing the distance to the pivot axis 15. During flexion, piston 32 is pressed downward, reducing the volume of the flexion chamber and correspondingly increasing the volume of the extension chamber, minus the volume of the retracted piston rod 33. An electric motor, driving a pump (not shown), can be arranged within housing 31 to generate pressure in one of the chambers, thereby pressurizing the fluid in one of the two chambers and causing piston 32 to move within the cylinder in one or the other direction. This results in flexion or extension movements of the orthotic device, in the form of a prosthetic leg. The electric motor driving the pump is an option, and in one embodiment, it can be used in conjunction with a hydraulic actuator 30.

[0046] In principle, passive prosthetic knee joints do not require a drive device or motor. Actuator 30, as an alternative to a passive linear damper, particularly linear hydraulic, is a rotary damper, particularly rotary hydraulic, magnetorheological resistance device, or electric motor, especially in combination with gear or screw drives. Here, the electric motor can operate in generator mode. In one embodiment, a combination of various resistance devices can also be implemented as the actuator.

[0047] A drive unit 34 is arranged inside or on the housing 31, coupled to at least one regulating valve 35, through which the hydraulic resistance in the actuator 30 can be changed. The actuator 30, and particularly the drive unit 34, is coupled to a control unit 40, which activates, deactivates, or modulates the drive unit 34 based on sensor values, thereby enabling the actuator 30, configured as a passive actuator, to provide adaptive resistance. In embodiments where the actuator 30 is configured as a magnetorheological resistance device, the resistance is changed by activating, deactivating, or modulating the magnetic field, and the drive unit 34 is an electromagnet or magnetic coil. In embodiments where the actuator 30 is configured as an active drive device with an electric motor, the resistance is changed by activating, deactivating, or modulating the voltage affecting the torque generated by the electric motor.

[0048] At least one sensor 50 is arranged on both the upper part 10 and the lower part 20 for detecting the spatial orientation of the lower part 20 or the upper part 10. Specifically, the sensor 50 for detecting spatial orientation is arranged only on the upper part 10. This sensor 50, for example, can be configured as an IMU (Inertial Measurement Unit) to determine spatial angles or absolute angles relative to a fixed spatial orientation (e.g., the direction of gravity) during the use of a prosthetic knee joint. Instead of being configured as an IMU for detecting spatial orientation, the corresponding sensor 50 can also detect other state data, particularly state data relating to the artificial knee joint. These state data include, in particular, position, angle, velocity, acceleration, force, and their processes or changes. The determined spatial angles or other state quantities of the upper part 10 and / or the lower part 20 are compared with threshold angles or threshold values. When a threshold value stored in the control device 40 for the corresponding sensor value or the quantity derived therefrom is reached or exceeded, the drive device 34 is modulated, activated or deactivated to change the flow resistance, viscosity, braking force, torque, stiffness or force against buckling motion in the actuator 30, which is formed as a hydraulic damper.

[0049] The actuator 30 in an artificial knee joint is typically used to modulate flexion and extension movements to generate or support an appropriate or desired motion. Extension is supported where necessary and is advantageously braked shortly before reaching maximum extension to avoid hard impact. Flexion is braked or blocked during the standing and swinging phases to ensure flexion limitation. To enable the drive 34 for actuating the regulating valve 35, the drive 34 is also equipped with an energy storage device, particularly in the form of a battery. The energy storage device can be arranged directly next to the drive 34 or in another location on the orthopedic device where more space is available or where weight distribution is more advantageous.

[0050] Furthermore, a control device 40 and at least one angle detection device as a sensor 50 are arranged on the prosthesis or orthosis. The angle detection device 50 detects the angle between the upper part 10 and the lower part 20, and is configured, for example, as a direct angle sensor for directly detecting the angle. Alternatively, the angle between the upper part 10 and the lower part 20 can be determined by evaluating sensor data from two spatial orientation sensors 50. Both methods can also be used simultaneously or complementaryly. Additionally, a sensor 50 for detecting at least one linear acceleration is arranged on the foot 25 to enable direct detection of the horizontal and / or vertical acceleration of the foot 25. All sensors arranged on the prosthesis or orthosis are coupled to the control device 40, and their sensor values ​​serve as the basis for controlling the drive mechanism 34 of the actuator 30 if the actuator is configured as a damper; or as input signals for motor control if the actuator 30 is configured as a motor. In the case of magnetorheological damping, the sensor values ​​are used to control the magnetic field or its changes. Based on sensor data, particularly spatial orientation and / or angular position, and data on the position, orientation, acceleration, and / or deformation of other components, the drive unit 34 is controlled to reduce or increase the pivoting resistance provided by the actuator 30. Not all sensors 50 must be arranged on the orthopedic device to perform this method.

[0051] exist Figure 2 The image schematically illustrates the initiation of a step or start from a standing position. At time t0 (in... Figure 2 (As shown in the left-hand diagram), the user is in a standing position. The feet do not necessarily have to be at the same height, as shown; other positions such as slightly apart, separated, leaning, bent, or squatting are also starting positions for walking. The supporting (or cared for) side is usually partially or fully loaded, but this is not necessary; for example, it can hang freely under the body or cross over the opposite leg. In this case, the orthotic joint device has typical basic characteristics that are advantageous for standing or other starting positions. For example, high flexion resistance in the extension position, or spring characteristics that increase with the flexion angle. The basic characteristics do not have to be constant, such as constant damping; instead, the system is in a state with specific controls for the starting situation.

[0052] The gait can now be initiated using the equipped side. For this, the equipped side is unloaded and steps forward, as shown at time t2. Typically, the body's center of gravity also shifts forward via the contralateral leg. At initial contact (occurring at time tIC), the prosthesis or orthosis should exhibit the typical characteristics of initial contact in walking, differing from those in the base position (here, standing). To provide these characteristics at initial contact, especially when the actuator speed is not infinitely fast, gait initiation is already identified during unloading and stepping forward with the equipped side, for example, by altering the characteristics during the forward step of the foot. This is achieved by adjusting the actuator. Ideally, the characteristics at the first initial contact should have little or no difference from the characteristics at the initial contact of each subsequent repetitive, cyclical gait sequence. Gait parameters such as speed and stride length can be taken into account in the characteristics.

[0053] Figure 3 This illustrates the initiation of a step or start while walking downhill (on an inclined surface). Similarly, the initial condition at time t0 is more or less static standing. When initiating a step downhill, the correct characteristics of the initial contact and subsequent early standing phase are more important than when walking on flat ground, as this primarily determines the user's descent speed. Excessive extension torque will cause a forward jerk, while insufficient extension torque will cause excessively rapid flexion. Furthermore, inappropriate characteristics are more difficult for the user to compensate for than when walking on flat ground. Now, when initiating a step—i.e., unloading the equipped side, stepping forward (t2), and then reloading (tIC)—characteristics optimized for downhill walking should be activated at initial contact. To this end, the equipped side stepping forward is identified, and characteristics are modified before initial contact; for example, by adjusting or changing the actuator control. Similarly, the characteristics at the initial contact of the first step should have little or no difference from the characteristics of each subsequent step in the gait cycle.

[0054] exist Figure 4 The figure illustrates the identification of step initiation. This initiation can be identified by various parameters determined by sensor 50. Typical characteristics of step initiation include unloading and stepping forward on the equipped side, the body propelling forward through the opposite side, the rearward rotation of the equipped side relative to the starting position, and the position of the foot relative to the hip, particularly when the foot is in front of the hip in the walking direction. Lateral shift of the body's center of gravity to the opposite side and unloading the equipped side are also indicators of step initiation. One or more of these indicators can be used to identify step initiation. Sensor data is the basis for identification. The figure shows the equipped side in a standing position at the same height as the unequipped side, and during the forward step, when the foot is in front of the unequipped side in the walking direction. The unequipped opposite foot remains unchanged during the forward step.

[0055] Figure 4The left figure shows the trajectories of the foot, knee, and hip in the sagittal plane. Step initiation can be identified through one or more trajectories. The trajectory s(t), or at least one of its components (e.g., horizontal or vertical), can be determined by distance measurements to the surrounding environment or the opposite side, positional changes using a positioning system, or integration of velocity and / or acceleration measures. Step initiation can be identified based on the trajectory. Movement of the equipped side relative to the opposite side or environment can be identified by relative velocity measurements, and step initiation can be inferred from this. Acceleration can also be considered, for example, step initiation can be identified when accelerating forward and / or subsequently accelerating backward. In addition to parameters and possible thresholds, processes involving one or more of these parameters can also be used for identification.

[0056] Alternatively or additionally, the tilt of one or more components can be used to identify step initiation, whether in the sagittal plane or other planes. The right figure shows the position of the segments in the sagittal plane and the leg cord as a line connecting the hip and ankle joints. The thigh and leg cord rotate backward as the foot steps forward. There is usually a slight backward tilt before the foot touches the ground because the foot is typically positioned in front of the body. These features can be used to identify step initiation.

[0057] Loading and unloading of orthotics or prostheses can be determined using force sensors and used to identify gait initiation, such as detecting the moment or state of unloading. Forces and torques can be measured to infer the loading state. The loading process can also be referenced, such as rapid unloading.

[0058] In particular, combinations of identified translational and rotational parameters can be used for identification, such as forward foot movement with backward leg rotation. Variations or parameters can involve position / orientation, velocity, and acceleration. Identification of stride initiation and characteristic changes may also occur only when a certain minimum stride length exists, which can be determined from the relative forward movement or rotation of the foot relative to the starting position and / or the position of the foot relative to the body. In addition to identification via thresholding and rule-based criteria, classification can also be performed using AI algorithms. Individual features and / or parameters can also be determined or estimated using AI algorithms.

[0059] exist Figure 5 The diagram illustrates the typical process of load, foot position, and lower leg angle over time t during standing, stepping forward, loading, and starting forward rolling. The annotations are as follows: t-time S - Initial state / Standing I-Step Start Status IC - Initial Contact B - The standing phase of the first stage of the cycle xF - The position of the feet below the body φ s - Absolute inclination of the lower leg f - Load / Axial force.

[0060] In the diagram on the left, the user is in the initial position at time t0, which is standing. In the diagram shown, the assistive device is fully loaded, supporting approximately half of the user's weight. Between t0 and t1, the assistive device unloads. Between t1 and t2, the foot steps forward, the lower leg rotates backward, with a noticeable backward tilt at initial contact tIC. Typical characteristics of the foot stepping forward also include a slight retraction of the foot and / or a counter-rotation of the thigh shortly before initial contact. At time t2, the foot stepping forward is identified, and the characteristics of the assistive device adjust accordingly. From the initial contact time tIC, the assistive device reloads, and the user rolls forward using the equipped leg. The foot position xF remains constant after the initial contact.

[0061] The diagram on the right illustrates a fundamentally similar process, but the assistive device here allows knee flexion during the unloading phase from standing. This applies, for example, to passive joints in the default release swing phase, which reduce flexion resistance upon unloading from standing. However, this could also be a special function, reducing flexion resistance only under specific conditions of unloading from standing. Flexion torque, resulting in knee flexion, is generated through hip flexion and foot contact with the ground. It is also possible for active joints to provide flexion torque upon unloading from standing, which can be considered negative flexion resistance. Knee extension can be caused by gravity and inertia, or by an internally applied extension torque.

[0062] For simplicity, we will assume the left-hand variant to be the standard method for future considerations. However, this should not be a limitation.

[0063] Figure 6 This illustrates the state changes of the system during gait initiation. The states shown relate to the system's state, particularly its characteristics, actuator control, and states identified by the control device, and do not necessarily refer to control via a state machine. Within the cyclical motion of the gait cycle, there is a cyclic sequence A→IC→B→...→A, such as walking on flat ground. The system is in state A before initial contact with IC, for example, the swing-phase extension with corresponding characteristics and actuator control. For example, extension stops at 4° flexion, and the optimal flexion resistance is set for walking with stance flexion. After initial contact with IC, the system passes through state B, for example, corresponding to stance flexion, and other states indicated only by "...", until the system is again in state A in the cyclic sequence. This process is applicable not only to... Figure 6 Also applicable Figure 7 .

[0064] To ensure the assistive device has optimal characteristics for the subsequent standing phase during the initial contact at the start, i.e., when the foot steps forward and loads itself, it is necessary to identify the forward step and modify the characteristics accordingly. The starting point is state S, which corresponds to standing in the diagram. The assistive device here, for example, has the knee angle at maximum extension and high flexion resistance. Now, when the equipped foot steps forward from the starting position, the control device recognizes this, and then the assistive device accordingly modifies its characteristics to prepare for the upcoming initial contact. For example, similar to the characteristics of state A in cyclic motion, the knee is slightly flexed (4°), and the flexion resistance is slightly reduced relative to standing to allow for a smooth transition into the standing flexion phase. Since the initially identified forward step of the foot does not necessarily correspond to the start, it is also possible to switch back to the characteristics of the starting situation, i.e., transitioning from I to S. Figure 6 As shown in Figure a). This can happen, for example, when the forward step is too long or the foot simply swings forward and then retracts and lands under the body.

[0065] The characteristics at the initial contact from states I and A need not be the same. For example, the knee flexion angle can be set to 2° when stepping forward, while it can be set to 4° during the swing-out extension phase of cyclic walking. However, if the control device controls the same characteristics regardless of whether it is a forward step from a standing position or a swing-out extension phase of cyclic walking, the result is as follows: Figure 6 The state diagram shown in Figure b) is as follows.

[0066] If the initial contact is not clearly identified, for example because there is no corresponding sensor to identify it, then processes c) and d) are obtained, in which the initial contact is between state A and B.

[0067] Figure 7 This illustrates the initiation of a gait based on contextual recognition. Walking control is typically context-dependent. That is, the assistive device exhibits different characteristics when walking in different contexts, such as walking on flat ground, going downhill on a slope, going downhill on a staircase, going uphill on a slope, or climbing stairs. Context also relates to the initiation of a gait starting from a standing position. When standing on flat ground, the initiation begins with walking on flat ground; when standing on a downhill slope, the initiation begins with walking downhill, and so on.

[0068] In control devices, this can be considered by also performing context recognition during the forward stepping of the foot while standing, and adjusting the characteristics to context-specific standing characteristics. For example, in Figure 7In the diagram, the cyclic sequence A1→IC1→B1→...→A1 represents walking on flat ground, and the cyclic sequence A2→IC2→B2→...→A2 represents walking downhill on a slope. ICi represents other cyclic sequences. Now, not only is the forward step of the foot identified, but the algorithm also identifies or estimates the context from the control device input data and adjusts the characteristics to be optimal for the standing period in the corresponding context. The adjustment of characteristics to the context can be discrete, thus selecting one from multiple context-specific characteristics. Alternatively, the adjustment to the context can also be continuous or smooth, which will... Figure 13 The explanation is as follows. Of course, any adaptation of the feature to other parameters (such as walking speed or stride length) can also be considered.

[0069] Figure 8 as well as Figure 9 Two examples of buckling resistance adjustment during initiation are shown. States S, I, IC, and B are labeled, along with control A for at least one actuator, where R is the resistance against bending. The description and names of the motion processes are the same as previously presented. Figure 1 In this embodiment, the auxiliary device exhibits load-related buckling resistance characteristics during standing. Under sufficient load, an optimal resistance R0 for standing is set. As the load decreases below a threshold, the buckling resistance continuously decreases from R0. This decrease can also enter the negative region, corresponding to the internally applied buckling moment. Accordingly, the buckling resistance R decreases with unloading from t1 to t2. The characteristics during standing do not necessarily correspond to constant resistance, but can generally be considered fixed.

[0070] At time t2, a forward step is detected. Subsequently, the flexion resistance increases to level R1, which is higher than the standing level and particularly advantageous for subsequent initial contact during the start-up. This is the case, for example, when a user can control the movement of the assistive device well at the existing resistance level R0 while standing, but at the initial contact of the start-up and subsequent initial contact of the subsequent steps within the gait cycle, the external flexion torque acting on the knee joint at level R0 is no longer or can no longer be reliably controlled. Accordingly, a higher level R1 ensures sufficient standing stability even at the first initial contact of the start-up. Level R1 may also be high enough to practically prevent knee flexion. The resistance process shown from t2 to tIC is the sum of the actuator settling time, desired temporal smoothing, and / or the dependence of the resistance level on other parameters (such as stride length or leg lean), both of which increase during the forward step of the foot.

[0071] exist Figure 9 The middle shows Figure 8 A variant. In this embodiment, the characteristics during standing (t0) and unloading are constant buckling resistance at the horizontal R0, but with... Figure 8The resistance levels differ. At time t2, the forward step of the foot is detected, and the flexion resistance is subsequently reduced to level R1. For example, this facilitates a smooth transition into stance flexion at the initial contact during initiation and at each subsequent initial contact within the gait cycle. Flexion resistance at stance would be too high for this purpose and would make stance flexion difficult or uncomfortable. Later in the stance phase, the flexion resistance can be increased again to limit knee flexion speed or achieve flexion cessation. Such control can be advantageous in different contexts, where the detailed implementation (e.g., initial resistance level or resistance increase) depends on the context. The resistance at initial contact should be as close as possible to the behavior at initial contact within the gait cycle. Similarly, the resistance progression from t2 to tIC is the sum of the actuator's maximum adjustment speed, desired temporal smoothness, and / or dependence on other parameters.

[0072] exist Figure 10 The diagram illustrates the adjustment of the effective spring stiffness and damping during start-up. In this embodiment, the actuator exhibits the characteristics of a parallel spring-damper system with adjustable spring stiffness c (μ) and damping d (η). This can be achieved, for example, by a motor drive that simulates damping and spring stiffness through corresponding control. Alternatively, it could be a hydraulic damper with a spring accumulator, whose stiffness and damping behavior can be altered. This combination is one of many implementations and should not be considered limiting; rather, combinations of parallel and series dampers, springs, etc., are all possible.

[0073] At time t0, when standing, the characteristics are essentially damped, with a constant damping level d0; the spring stiffness is low. This is reasonable to allow unrestricted knee flexion for sitting or kneeling while standing. High spring stiffness would prevent this. At time t2, the forward step of the foot is now recognized, and damping is subsequently reduced while spring stiffness is increased to prepare for increased initial contact during subsequent starts. Low damping and high spring stiffness allow for particularly comfortable standing flexion. Furthermore, when using a spring accumulator, energy can be stored during standing flexion instead of dissipated through the damper.

[0074] exist Figure 11 middle Figure 10 A variant of this. In this embodiment, the actuator has at least one switching element, or the actuator is a switching element, for example, capable of engaging and disengaging a spring, which is... Figure 11 The left side shows the diagram. Alternatively, the spring accumulator in the hydraulic system can be activated or deactivated by selectively connecting port P2 to P0 or P1 via a switching valve. In this embodiment, only a small amount of resistance exists when the spring is disengaged or the spring accumulator is disconnected. When the spring is engaged or the spring accumulator is activated, the corresponding spring force comes into play.

[0075] The initial position here is position σ=0, corresponding to a disengaged spring or a disconnected spring accumulator. Lower motion resistance can be useful for assistive devices that allow the user good control while standing, even without stability during the standing phase, and provide them with maximum freedom of movement. This is true, for example, for orthotics for individuals with high residual function or exoskeletons for unrestricted individuals. In contrast, the spring element or spring accumulator should stabilize during the standing phase at the initial contact of walking. To ensure this stability at the initial contact of initiation, the forward step of the foot is detected (time point t2), and subsequently, in preparation for enhanced initial contact, the switching element is switched to position σ=1, thereby engaging the spring or connecting the spring accumulator to a hydraulic piston.

[0076] In this case, the diagram shows the desired switching position, which in this specific example does not change with other parameters or undergo time smoothing. The actual switching position will, of course, be reached with a certain time delay due to system inertia; this is why it is desirable to switch before recognizing the initial contact.

[0077] Alternatively, the switching element can activate or deactivate locks, couple or decouple degrees of freedom, switch characteristics (e.g., damping, stiffness, friction, transmission ratio, etc.) between two discrete values, or switch between other discrete states. The switching element can also be part of an actuator that can adjust other characteristics. For example, in parallel with a switchable spring or a switchable spring accumulator, a passive or active resistance device can be arranged that functions even when the spring is decoupled or the spring accumulator is disconnected.

[0078] exist Figure 12The diagram illustrates how an actuator alters a degree of freedom during initiation. For example, the knee joint can be extended or flexed via a motor or a pre-loaded energy storage device. A degree of freedom can be restricted by a resistance device. Similarly, the derivative of a degree of freedom can be altered and / or restricted. The diagram shows the degree of freedom φ altered by the actuator. In the exemplary embodiment below, this is the knee joint angle. In the initial standing position (t0), the assistive device is in a fully extended position. The knee joint is in position φ0. The arrangement and characteristics of the assistive device elements, along with the positioning of the knee joint axis, generate a knee joint torque of extension or minimal flexion during standing. This is advantageous for stable standing. However, it is advantageous for the knee joint to have a slightly flexed position at the initial contact of walking. In particular, this reduces the impact on the user and facilitates flexion during the initiation of standing. This can now be identified (t2) when the assistive device is unloaded from standing and the foot steps forward, and the knee joint can be flexed by the actuator. Thus, at the first contact with the ground after initiation, the equipped side already has a slightly flexed position φ1. If knee flexion is allowed or actively supported during unloading and stepping forward, the subsequent extension can be stopped when the desired slight pre-flexion angle of the knee is reached.

[0079] Figure 13 The continuous adaptation of features to context is illustrated, which in the illustrated implementation is performed continuously, meaning there is a smooth transition between different contexts, expressed by a continuous parameter λ. Context recognition can be performed, for example, by fuzzy logic or an AI algorithm with context-continuous probabilities (which may be interpolated or weighted accordingly). Alternatively, context recognition is performed by parameterization that smoothly transitions to other contexts, such as calculating or estimating the ground slope during a downhill slope, which smoothly transitions from a 0° slope to walking on flat ground. Planar sections where λ = constant correspond to one of the preceding figures respectively. The features of the assistive device are correspondingly continuously adapted with respect to the parameter λ. This can be done not only during initiation or the forward step of the foot, but also within different cyclic movements. For example, during initiation and the standing phase of a downhill slope, features can be continuously adapted according to the slope. However, discrete branches may also occur after continuous adaptation, and vice versa.

Claims

1. A method for controlling an orthopedic knee joint device comprising: an upper portion (10), a lower portion (20), and a foot portion (25) fixed to the lower portion, wherein at least the upper portion (10) and the lower portion (20) are pivotally hinged to each other about a pivot axis (15); an actuator (30) coupled to and influencing pivotal movement of the upper portion (10) and the lower portion (20), wherein the actuator (30) is coupled to a control device (40) coupled to at least one sensor (50) and activating, deactivating, or modulating the actuator (30) based on a sensor value of the at least one sensor (50), characterized in that, Displacement of the foot (25) is detected by detecting and evaluating linear acceleration and / or positional changes of the upper part (10), the lower part (20) and / or the foot (25), and the flexion resistance is altered relative to the initial state before displacement during the swing period or the load response of the foot (25).

2. The method according to claim 1, characterized in that, The initial state is standing or a situation different from walking, in which the foot (25) is in contact with the ground.

3. The method according to claim 1 or 2, characterized in that, The displacement includes lifting the foot (25), which is determined by the decrease of the axial force component in the foot (25) and / or the lower part (20) and / or the vertical acceleration of the foot (25) and / or the lower part (20) and is used as a criterion for lifting or the presence of a swing period.

4. The method according to any one of the preceding claims, characterized in that, During the displacement, the resistance against flexion during the swing phase remains constant during the lift phase, and the resistance against flexion during the swing phase decreases and / or sets the joint angle before the foot (25) touches the ground.

5. The method according to any one of the preceding claims, characterized in that, At least one linear acceleration of the upper part (10), the lower part (20) and / or the foot (25) is determined by at least one sensor (50).

6. The method according to any one of the preceding claims, characterized in that, Determine the linear acceleration of the foot (25) in the walking direction.

7. The method according to any one of the preceding claims, characterized in that, The linear acceleration is measured at the foot (25) or calculated based on the linear acceleration of the lower part (20) combined with the angular acceleration of the lower part (20) or the linear acceleration of the upper part (10) combined with the knee angle and the angular acceleration of the lower part (20).

8. The method according to any one of the preceding claims, characterized in that, Detect the ankle joint torque at the foot (25) and / or the lower part (20), and use the decrease in ankle joint torque as a criterion for the presence of a lift or swing phase.

9. The method according to any one of the preceding claims, characterized in that, The knee joint torque around the pivot axis (15) is detected and used as a criterion for the presence of a lifting or swinging phase.

10. The method according to any one of the preceding claims, characterized in that, Additionally, the spatial orientation of the upper part (10), the lower part (20) and / or the foot (25) is used as a criterion for the presence of a lifting or swinging period.

11. The method according to claim 10, characterized in that, The backward tilt of the lower part (20) in space, observed from the distal end (21) of the lower part (20), is used as a criterion for the presence of a lifting or swinging period.

12. The method according to any one of the preceding claims, characterized in that, The orientation of the upper part (10), the lower part (20) and / or the foot (25) in space outside the threshold is used as a criterion for the absence of a lifting or swinging period.

13. The method according to any one of the preceding claims, characterized in that, Real-time determination and evaluation of sensor values.

14. The method according to any one of the preceding claims, characterized in that, The duration for which the sensor value is outside the time window is used as a criterion for the absence of a lift or swing period.

15. The method according to any one of the preceding claims, characterized in that, The buckling resistance during load response corresponds to the buckling resistance during initial contact during travel in a plane.

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