Method of controlling prosthetic limbs or orthotic devices

Abstract

The present invention relates to a method for controlling a prosthetic or orthotic lower limb having an upper part (10) and a lower part (20) connected to the upper part (10) via a knee joint (1) and pivotably supported relative to the upper part (10) about a joint axis (15), wherein an adjustable resistance device (40) is arranged between the upper part (10) and the lower part (20), and via this resistance device, the flexion resistance (Rf) is changed based on sensor data, and an axial force (FA) acting on the lower part is detected by at least one sensor (54) and used as a basis for changing the flexion resistance (Rf), wherein the flexion resistance (Rf) is reduced when the axial force (FA) of the leg chord (70) and / or the extended knee joint (1) decreases and / or when the position is approximately vertical, and the flexion resistance (Rf) is increased again when no knee flexion is detected within a timed interval and / or when the knee joint (1) and / or the leg chord (70) and / or the axial force (FA) falls below or exceeds a certain limit value.

Description

Technical Field

[0001] The present invention relates to a method for controlling a lower limb prosthesis or orthosis having an upper part and a lower part connected to the upper part via a knee joint and supported so as to be pivotable about a joint axis with respect to the upper part, wherein an adjustable resistance device is arranged between the upper part and the lower part, the flexion resistance is changed based on sensor data via the resistance device, the axial force acting on the lower part is detected by at least one sensor, and is used as a basis for changing the flexion resistance.

Background Art

[0002] Artificial knee joints are used in prostheses, orthoses, and exoskeletons as a special case of orthoses. An artificial knee joint has an upper part and a lower part that are pivotably supported relative to each other about a joint axis, i.e., a knee axis. In the simplest case, the knee joint is formed as a single-axis knee joint in which, for example, bolts or two bearing locations arranged on a pivot axis form individual knee axes. There are also known artificial knee joints that have sliding surfaces or revolving surfaces, or a plurality of links connected to each other in an articulated manner, rather than forming a fixed rotation axis between the upper part and the lower part. In order to be able to influence the movement characteristics of the knee joint and to obtain the movement behavior of an orthosis, prosthesis, or exoskeleton that is close to natural walking behavior, a resistance device capable of changing each resistance is provided between the upper part and the lower part. A completely passive resistance device is a passive damper such as a hydraulic damper, a pneumatic damper, or a damper that changes the movement resistance based on the magnetorheological effect. There are also active resistance devices such as motors or other drive devices that can operate as generators or energy storage devices by means of appropriate interconnections.

[0003] Each knee joint, i.e., a prosthetic or orthotic knee joint, is secured to the patient by its respective connecting means. In the case of a prosthetic knee joint, fixation is usually performed by a femoral socket that accommodates the stump of the limb. Alternative types of fixation are also possible, for example, by osseointegration connecting means, or via straps and other devices. In the case of orthoses and exoskeletons, the upper and lower parts are directly fixed to the thigh and lower leg. The attachment devices provided for this purpose are, for example, belts, cuffs, shells, or frame structures. The orthosis may also have a foot portion for supporting the foot or shoe. The foot portion can be articulated at the lower part.

[0004] DE10 2013 011 080A1 relates to a method for controlling an orthopedic articulated joint device of a lower limb having an upper part and a lower part articulatedly supported to the upper part, wherein a converter is placed between the upper and lower parts, and this converter converts the mechanical work from the relative motion during the rotation of the upper part relative to the lower part and stores it in at least one energy reservoir. The stored energy is supplied back to the joint device with a time delay to support the rotation of the upper and lower parts during the course of movement. The support for the relative motion is performed under control. In addition to the converter, a separate damper in the form of a hydraulic or pneumatic damper may be provided, and the damper is made adjustable so that during walking the damper device can influence resistance in both the flexion and extension directions.

[0005] Artificial knee joints have a knee angle of 180° at their structurally achievable maximum extension, and hyperextension, which corresponds to a posterior angle greater than 180°, is not typically intended. The rotation of the lower part of the knee posteriorly relative to the upper part is called knee flexion, and the rotation of the lower part, or in the direction of forward rotation, is called extension.

[0006] Passive control of the prosthetic knee joint through adjustable damping of flexion resistance is known from DE10 2006 021 802 A1. Stair climbing is adapted, detecting low-moment lifts of the prosthesis and reducing the flexion damping during the lifting phase to a level below that suitable for level walking. Flexion damping can be increased in response to changes in knee angle and axial forces acting on the lower leg.

[0007] Furthermore, there are control methods that allow for the adjustment of flexion resistance according to each walking situation, enabling alternating foot placement on flat ground. For example, special situations requiring knee flexion, such as starting to walk from a standing position, especially with prosthetics or orthoses, present challenges.

[0008] Therefore, the objective of the present invention is to provide a method that allows users to use an artificial knee joint more comfortably.

[0009] According to the present invention, the above problems are solved by a method having the features of the main claim. Advantageous embodiments and variations of the present invention are disclosed in the dependent claims, the following description, and the drawings.

[0010] A method for controlling a prosthesis or orthosis of a lower limb having an upper part and a lower part connected to the upper part via a knee joint and supported relative to the upper part so as to be rotatable about an articular axis, wherein an adjustable resistance device is placed between the upper and lower parts, thereby changing the flexion resistance based on sensor data, and the axial force acting on the lower part is detected by at least one sensor and used as the basis for changing the flexion resistance, the method intends that the flexion resistance decreases when the axial force of the gait chord and / or extended knee joint decreases and / or when the position is nearly vertical, and when no knee flexion is detected within a time-specified interval and / or when the knee joint and / or gait chord and / or axial force exceeds a certain limit value. The above conditions are not met, for example, when the knee joint is significantly or completely entlasted in the axial direction. The axial force is detected, for example, by an axial force sensor located on the prosthesis or orthosis, particularly the lower part, or a component attached to the lower part. For example, if forward rotation of the joint axis is detected, which can occur during a rolling motion by bending the lower leg around the ankle joint axis, flexion resistance is reduced. Forward rotation of the joint axis, and therefore the entire knee joint, means that the joint axis, and therefore the proximal end of the lower part, also rotates around a distal center of rotation, in which case the distal center of rotation may be the joint axis of the ankle joint or a moving point on the sole of the foot. Alternatively, or in addition to the above, flexion resistance is also reduced if the vertical position of the leg chord is detected. The leg chord is defined in particular as a connecting line between two defined points in the upper and lower or lower adjacent parts. A preferred embodiment intends that the leg chord is defined as a connecting line between a point proximal to the upper joint axis and a point distal to the lower joint axis, for example, between the hip joint center of rotation and a foot point. The hip joint center of rotation is determined by an orthopedic technician in any case when using a prosthetic knee joint, and determines the length of the thigh or upper segment, which is defined as the distance between the joint axis or knee axis and the hip joint center of rotation. The length of the lower segment is defined by the distance between the knee axis and the foot point.For a prosthetic leg, the foot point can be defined as the center of the foot, the instantaneous pole of the rolling motion, the foot at sole level or the endpoint of the vertical line of the lower leg on the ground, or the endpoint of the vertical line of the lower leg on the ground. Other points close to the ground are also suitable for defining the foot point. In the case of orthoses or exoskeletons, the distance between the ground and the joint axis can also be used, as there is no need for a foot to support the remaining natural foot (natuerlicher Fuss). The position and / or length of the gait chord provides reliable information about the orientation and progression of the leg's movement. The gait chord can be calculated or estimated by an absolute angle sensor in combination with a known segment length, an absolute angle sensor, and a knee angle sensor. A positive gait chord angle occurs when the gait chord is tilted posteriorly in the sagittal plane. This is, for example, when the foot or ankle joint axis is in front of the knee or knee joint axis when viewed in the direction of forward walking. A negative gait chord angle occurs when the gait chord is tilted forward, for example, when the knee and hip joints are in front of the knee joint axis. When the chord angle is positive, an increase in the distance of the chord relative to the vertical is considered positive as an increase or expansion. When the chord angle is negative, an increase in the distance of the chord relative to the vertical is considered negative as a decrease or contraction.

[0011] Alternatively, or in addition to, if knee extension is detected, the flexion resistance is also reduced. The reduction in flexion resistance is maintained only for a specified time range, then reversed, and the flexion resistance can be increased to the same or a different level. In particular, if no knee flexion is detected within a specified interval, the flexion resistance is increased.

[0012] Alternatively, or in addition to this, flexion resistance increases when the knee joint and / or ligament is no longer in a nearly vertical position, and / or the knee joint is significantly or completely unloaded axially. When the ground reaction force no longer acts in the longitudinal direction of the joint axis in the lower part, flexion resistance increases again, even if the knee joint is completely unloaded, provided that at least one of the other criteria for increasing flexion resistance again is met. This method makes it possible to achieve easy flexion of the knee joint, for example, to start walking from a standing position. When the prosthesis or orthosis is unloaded, for example, when weight is shifted to the opposite side, flexion resistance is automatically reduced, and flexion can be performed without flexion resistance, and therefore with significantly reduced flexion resistance. This makes it possible to move the knee joint slightly forward even when in contact with the ground, without completely lifting the orthosis or prosthesis off the floor, due to compensatory movement between the hip (Huefte) and pelvis. The foot or prosthesis can be rotated forward until the effective length of the prosthesis or orthosis is reduced by knee flexion, allowing for forward rotation without contact with the ground. This method keeps the knee joint fixed under axial load during the stance phase, resulting in high patient stability and greater confidence in the prosthesis or orthosis. Simultaneously, sufficient dynamics are provided within the knee joint, enabling a comfortable initiation of the swing phase even in specific situations. [Prior art documents] [Patent Documents]

[0013] [Patent Document 1] German Patent Application Publication No. 102013011080 Specification [Patent Document 2] German Patent Application Publication No. 102006021802 Specification [Overview of the project]

[0014] One advanced form of the present invention aims to reduce flexion resistance when starting to walk from a standing position, and in particular, only when starting to walk from a standing position. The standing state can be recognized or detected, for example, by tracking axial force over time. If the axial force is constant or nearly constant over a defined period, it can be assumed that the user of the prosthesis or orthosis is standing without moving. Typically, when a user of an orthosis or prosthosis stands on both legs, they place about half their body weight, and sometimes somewhat less, on the prosthesis or orthosis. This weight range can be defined as a limit value. If the measured axial force is within this limit value range over a specific time horizon, this can be considered a prerequisite for the above process to begin. The same can be done by monitoring the flexion angle. If the knee joint remains in the extended position without flexion for a certain period, this can be used alone or in combination with axial force monitoring as an indicator that the user of the orthosis or prosthosis is standing. Standing can be distinguished from forward movement, walking, and / or one or a gait cycle using multiple IMUs.

[0015] Bending resistance can be reduced in accordance with the decrease in axial force, and it is particularly advantageous to gradually decrease the bending resistance toward a target value. When the axial force is initially reduced slightly, the bending resistance decreases relatively significantly, and therefore, for example, starting from a lock due to maximum hydraulic resistance, if the decrease in axial force is relatively small, it is basically possible to bend against the bending resistance. As the decrease in axial force progresses, the decrease becomes less significant.

[0016] Flexion resistance can be reduced to a level lower than the stance phase attenuation, especially to a level lower than the stance phase attenuation during walking on level ground.

[0017] The reduction of bending resistance can be dependent on axial force, chord angle, and / or lower spatial angle, in which case multiple or all characteristic quantities can be considered when calculating and determining how the reduction of bending resistance should occur. In addition to a pure switching of bending resistance when a determined limit is reached, exceeded, or fallen below, smooth transitions and resistance changes can also be regulated and induced depending on changes in characteristic quantities.

[0018] In one advanced form of the present invention, no reduction in flexion resistance occurs when the axial force decreases from a starting value, for example, the axial load while standing with both legs relaxed (entspanntes Stehen), to a level exceeding a limit value, for example, a level exceeding 10% of body weight, and when a straddle angle exceeding the limit value, particularly exceeding 5°, is detected. If the straddle moves backward, for example, rotates backward or to the rear at an angle of 5° or more, no reduction in flexion resistance occurs if a sufficient reduction in the magnitude of the axial force does not occur. The hip or hip joint moves behind the foot or distal reference point to determine the straddle. If the axial force decreases sufficiently and the straddle rotates backward in response, it can be concluded that the patient is attempting to sit down, for which high flexion resistance is advantageous to provide a high level of safety against knee joint collapse (Kollabieren). If a decrease in backward rotation of the straddle is detected, the flexion resistance decreases accordingly, and if there is no backward rotation of the straddle, a complete reduction in flexion resistance is possible.

[0019] In one variant of the present invention, no reduction in flexion resistance occurs when the axial force is reduced to a level below a limit value, for example, to less than 10% of body weight, and when the detected leg chord angle is outside a defined angular range around the vertical, for example, when the positive leg chord angle exceeds 30° or the negative leg chord angle is less than -10°. Such situations may occur, for example, when walking backward or when stepping over obstacles with large strides.

[0020] A complete decrease in flexion resistance can be achieved at positive chord angles up to 20°, and flexion resistance increases as the chord angle increases beyond that. Alternatively, a complete decrease in flexion resistance can be achieved at negative chord angles less than -10°. In contrast, flexion resistance increases as the chord angle decreases.

[0021] One variant of the present invention aims to ensure that no reduction in bending resistance occurs when the axial force is reduced to a level below a limit value, for example, to less than 10% of the user's weight of the orthosis or prosthesis, and when a lower inclination angle within a defined angular range around the vertical is detected, i.e., when the so-called roll angle is within a defined range near the vertical, and in particular when the positive roll angle is less than 15° and the negative roll angle is greater than -5°.

[0022] A complete reduction in bending resistance can be achieved when the positive inclination angle of the lower section is 20° or greater; if the inclination angle is smaller, the bending resistance increases. Alternatively, a complete reduction in bending resistance occurs from a negative inclination angle of -10°, and as the negative inclination angle increases, i.e., when the lower section is tilted in the direction of the vertical, the resistance either increases or does not decrease.

[0023] Flexion resistance can be increased when extension movement occurs at the knee joint, and this can be detected by a knee angle sensor. This can also be done by evaluating IMU data. For example, flexion resistance increases when a gait cycle is detected by a repetitive load loading pattern or movement pattern, such as a regular flexion angle of the knee or ankle joint. Flexion resistance can also be increased when axial force increases.

[0024] If a downward tilt is recognized, the flexion resistance cannot be reduced. In particular, this method is used to facilitate placing the foot or prosthesis immediately below the edge of the next step, or on the step, when sitting, walking backward, stepping over an obstacle, and descending stairs. In this case, in the above case, is the reduction of flexion resistance that should facilitate the start of walking from a standing position not performed, not performed to the same extent, or canceled? This not only facilitates the movement sequence in the above-described examples but also ensures the safety of the user in these examples.

[0025] In particular, a method for controlling a prosthetic limb or prosthesis for a lower limb having an upper part and a lower part connected to the upper part via a knee joint and pivotally supported about a joint axis with respect to the upper part, wherein an adjustable resistance device is arranged between the upper part and the lower part, the flexion resistance is changed based on sensor data via the resistance device, the axial force acting on the lower part is detected by at least one sensor, and the method used as a basis for changing the flexion resistance is such that when the axial force decreases, the flexion resistance decreases from the initial value, particularly when the flexion angle does not exceed a limit value, it is used for starting to walk from a standing position. In particular, the limit value can be specified as a value of 10° or less. This method is particularly used to adjust the flexion resistance when the user tries to make a movement different from flat walking rather than the walking cycle. When it is recognized that the user enters the walking cycle, knee extension is performed, or the axial load in the joint axis direction increases again, the reduction of damping or the decrease of resistance is not performed or is aborted.

[0026] Hereinafter, embodiments of the present invention will be described in detail based on the accompanying drawings.

Brief Description of the Drawings

[0027] [Figure 1] It is a schematic diagram of a prosthetic leg. [Figure 2] It is a diagram of the Achilles tendon. [Figure 3] It is a diagram of the profile of the axial force, resistance, and knee angle when descending stairs. [Figure 4]This diagram shows the profile of flexion resistance with respect to the chord angle and roll angle. [Figure 5] This diagram shows the profile of flexion resistance with respect to the chord angle and roll angle. [Figure 6] This diagram shows the profile of flexion resistance with respect to the chord angle and roll angle. [Figure 7] This is a diagram of an orthotic device. [Modes for carrying out the invention]

[0028] Figure 1 shows a schematic diagram of an artificial knee joint 1 used in a prosthetic leg. Instead of being used in a prosthetic leg, a suitably designed artificial knee joint 1 can also be used in an orthosis or exoskeleton. Next, instead of replacing the real joint, each artificial knee joint 1 is positioned medially and / or laterally to the real joint. In the illustrated embodiment, the artificial knee joint 1 is formed in the form of a prosthetic knee joint comprising an upper part 10 having an anterior side 11 located forward or in the direction of walking, and a posterior side 12 located opposite the anterior side 11. The lower part 20 is supported on the upper part 10 so as to be rotatable about a pivot axis 15. The lower part 20 also has an anterior side 21 or front side and a posterior side 22 or rear side. In the illustrated embodiment, the knee joint 1 is formed as a monocentric knee joint, although it is also possible to suitably control a multicentric knee joint. A foot portion 30 is positioned at the distal end of the lower portion 20, and the foot portion can be used as a fixed foot portion 30 with an immobile ankle joint, or it can be connected to the lower portion using a pivot axis 35 to enable a movement sequence that closely resembles a natural movement sequence.

[0029] The knee angle KA is measured between the posterior side 12 of the upper part 10 and the posterior side 22 of the lower part 20. The knee angle KA can be measured directly by a knee angle sensor 25 which can be positioned in the region of the pivot axis 15. The knee angle sensor 25 can be coupled to a moment sensor, or may have such a moment sensor, to detect the knee moment around the joint axis 15. An inertial angle sensor or IMU 51 is positioned in the upper part 10, and this sensor measures the spatial position of the upper part 10 in relation to a constant force direction, such as gravity G pointing vertically downward. An inertial angle sensor or IMU 53 is also positioned in the lower part 20 to detect the spatial position of the lower part during use of the prosthesis.

[0030] In addition to the inertial angle sensor 53, an acceleration sensor and / or a lateral force sensor 53 can be placed in the lower part 20 or the foot part 30. The axial force FA acting on the lower part 20 or the ankle moment acting around the ankle joint axis 35 can be detected by the force sensor or moment sensor 54 in the lower part 20 or the foot part 30.

[0031] A resistor 40 is positioned between the upper 10 and the lower 20 to influence the rotational motion of the lower 20 relative to the upper 10. The resistor 40 can be configured as a passive damper, a drive device, or a so-called semi-active actuator 40 capable of storing kinetic energy and releasing it again at a later time to brake or assist motion. The resistor 40 can be configured as a linear resistor or a rotational resistor. The resistor 40 is connected to a control device 60, for example, by wire or wireless connection, and the control device is also coupled to at least one of the sensors 25, 51, 52, 53, and 54. The control device 60 electronically processes signals transmitted from the sensors using a processor, computing unit, or computer. The control device has an electrical energy supply unit and at least one memory unit, the memory unit stores programs and data and is provided with an internal memory device for processing the data. After processing the sensor data, an operation or deactivation command is output to activate or deactivate the resistor 40. By operating the actuator within the resistor 40, for example, a valve can be opened or closed, or a magnetic field can be generated to change braking behavior.

[0032] The upper part 10 of the prosthetic knee joint 1 is fitted with a prosthetic socket used to accommodate the femoral stump. The prosthesis is connected to the hip joint 16 via the femoral stump, and the hip joint angle HA is measured on the anterior side of the upper part 10, which is provided anteriorly 11 between a vertical line passing through the longitudinal extension of the hip joint 16 and the upper part 10 and the line connecting the hip joint 16 and the knee joint axis 15. When the femoral stump is lifted and the hip joint 16 is flexed, the hip joint angle HA decreases, for example, when sitting. Conversely, the hip joint angle HA increases during extension, for example, when standing up or in a similar movement sequence.

[0033] During the gait cycle of walking on level ground, the foot 30 first makes contact with the ground on the heel, and this initial contact of the heel or the heel portion of the foot 30 is called the heel strike. Subsequently, plantarflexion occurs until the foot 30 is fully on the ground, at which point the longitudinal extension of the lower part 20 is usually behind the vertical line passing through the ankle joint axis 35. Then, during walking on level ground, the body's center of gravity moves forward, the lower part 20 rotates forward, the ankle angle AA decreases, and the load on the toes increases. The ground reaction force vector moves forward from the heel to the toes. At the end of the stance phase, toe-off occurs, followed by the swing phase, during which the foot 30 moves behind the center of gravity or the ipsilateral hip joint with a decreasing knee angle KA during walking on level ground, then rotates forward after reaching the minimum knee angle KA, and then usually reaches heel strike again with the knee joint 1 fully extended. Therefore, the force application point PF moves from the heel to the toes during the stance phase, as schematically shown in Figure 1.

[0034] In Figure 2, the definition of the leg chord 70 of the ipsilateral, mounted leg, and the definition of the leg chord of the contralateral, non-mounted leg are shown. The leg chord passes through the hip joint rotation center 16 and forms a line to the ankle joint 35. As can be seen from Figure 2, the length and direction φ of the leg chord 70 are shown. L This changes during motion, especially when the gradient varies considerably. The elevation difference ΔH that must be overcome can be estimated, predicted, or detected by the profile of the change in length and / or direction of the leg chord 70. From this, the respective control commands are derived. Gravity direction G and opposite leg chord φ Lk The opposite chord φ on the same side Li The orientation of each is described.

[0035] In Figure 3, the change in flexion resistance Rf is shown along with the flexion angle Af profile and the axial force FA profile. This walking scenario corresponds to starting to walk on the prosthetic leg at the beginning of a staircase, placing the prosthesis on the step immediately below, and performing knee flexion without any reduction in flexion resistance. At the start of the movement at the left end of the flexion angle profile, the knee joint is maximally extended, the knee angle KA is approximately 180°, and therefore the flexion angle AF is 0 or nearly 0. The maximum axial force FA is applied to the prosthetic knee joint, and the prosthesis user attempts to descend the stairs starting with the prosthetic leg or the ipsilateral leg. For this reason, the axial force FA decreases first, and with a slight time delay, the flexion resistance Rf also decreases, thereby making flexion easier and allowing the flexion angle Af to increase. The flexion resistance Rf decreases to approximately 25% of its initial value. Braking or complete elimination of flexion resistance Rf is not planned. Even if the artificial knee joint is completely unloaded and the axial force FA is eliminated, no further reduction in flexion resistance RF will occur. The knee joint flexes, increasing the flexion angle Af, which in turn causes the hip joint to flex, moving the knee joint and joint axis forward. The foot or prosthesis rotates over the edge of the stairs, resulting in extension, and thus a reversal of the motion profile of the flexion angle AF. After reaching the maximum flexion angle and reversing the motion, the flexion resistance Rf increases very rapidly again back to its initial value and remains at the starting level.

[0036] The flexion resistance Rf remains at a high level until movement continues and the prosthesis makes contact with the step immediately below, which can be recognized by a significant increase in axial force FA, thereby ensuring proper stance phase decay after the prosthetic leg makes contact with the ground. The flexion resistance Rf decreases again only when the axial force FA decreases, i.e., when the prosthetic knee joint is newly released from load for the purpose of walking on level ground or descending further stairs.

[0037] In Figure 4, the axial force Af and the chord angle α are shown. LCA profile of the resistance Rf change depending on the direction is shown. The chord angle αLC of the chord is positive when the chord 70 is tilted posteriorly relative to the vertical line or gravity line G, starting from the distal reference point or foot point. A schematic diagram of the direction is shown in the left part of Figure 4. The more the chord 70 is tilted posteriorly, i.e., the more the hip joint 16 is behind the foot point or ankle joint in the sagittal plane, the larger the positive tilt angle of the chord 70. When the axial load on the prosthesis is reduced to, for example, more than 10% of the total body weight, or to a force equivalent to 40% to 15% of body weight, the resistance Rf is reduced to its maximum, in the illustrated embodiment, to 25% of the initial resistance, in the nearly vertical direction. As the posterior tilt of the chord 70 increases and the positive chord angle αLC increases, the flexion resistance Rf does not decrease much, in the illustrated embodiment, until it reaches a limit specified as 5% for posterior tilt, and there is no reduction in flexion resistance Rf; the flexion resistance Rf is 100%.

[0038] Figure 5 shows another variation of the reduction in flexion resistance Rf depending on the axial load and the chord angle αLC. When the axial load is less than 10% of body weight, for example, 0% to 10% of body weight, i.e., when the axial load continues to decrease compared to standing with both legs in a relaxed state, the flexion damping or flexion resistance Rf is adapted differently from the case of slight load release shown in Figure 4. When the chord 70 is tilted significantly backward at an angle of 20° to 30°, such as when climbing over an obstacle, the reduction in flexion resistance Rf is either nonexistent or limited. From a chord angle αLC of 20°, the resistance can be reduced to the target value as the axial force decreases, but not from an angle of 30°. When the direction of the chord is negative, i.e., when the chord 70 moves forward, the reduction only occurs at 10°, reaching the target value, up to 40% of the maximum resistance in the illustrated embodiment, and as the forward tilt increases, only a slight reduction is possible, or even no reduction at all, even if the axial load decreases. A negative leg chord angle αLC is observed, for example, when walking backward. As shown in Figure 5, the flexion resistance Rf can decrease and increase over a specific angular range, or alternatively, it can transition in the form of abrupt decreases and increases. This type of adaptation has been found to be particularly advantageous, especially in the negative angular range, i.e., when the lower 20 is tilted forward.

[0039] Figure 6 shows another example of the dependence of resistance reduction on other sensor signals depending on the load application. The reduction in axial force Af follows the level shown in Figure 5, not the level shown in Figure 4, so the reduced axial force Af is less than 10% of body weight. The axial force can be reduced to, for example, 0% or 5% of body weight on the mounted leg. Figure 6 shows the roll angle αS measured between the lower part 2 and the vertical line G as another criterion for reducing flexion resistance. In this case, the vertical line G extends to the ground through the pivot axis 35 of the ankle joint between the foot 30 and the lower part 20, or through the center of rotation if the foot 30 is fixedly connected to the lower part 20. A backward displacement results in a positive roll angle αS. A forward displacement, where the knee joint is positioned in front of the vertical line G at the joint axis 15, results in a negative roll angle αS. For example, if the negative roll angle exceeds -10° relative to the vertical line G, the flexion resistance Rf is reduced completely, in this case also to 40% of the initial resistance. As the forward tilt decreases, i.e., as the negative roll angle αS decreases, the bending resistance Rf increases, and therefore the decrease decreases. For a positive roll angle αS, the complete decrease in bending resistance Rf to the target value occurs at an angle of 20°, and no decrease occurs until an angle of 15°.

[0040] Figure 7 schematically shows one embodiment of an orthosis having an upper part 10 and a lower part 20 pivotably supported thereon around a pivot axis 15, and the present invention can also be carried out with this orthosis. In this embodiment, an artificial knee joint 1 is formed between the upper part 10 and the lower part 20, positioned laterally to the real knee joint. In addition to positioning the upper part 10 and the lower part 20 on one side of the leg, two upper and lower parts can also be positioned medially and laterally to the real leg. The lower part 20 has a foot portion 30 at its distal end, pivotably supported to the lower part 20 around an ankle joint axis 35. The foot portion 30 has a footplate on which a foot or shoe can be placed. Fixing devices for fixing to the lower leg or thigh are provided on both the lower part 20 and the upper part 30. The foot portion 30 may also have a device for fixing the foot to the foot portion 30. The fixing devices can be formed as clasps, belts, fasteners, or similar to allow the orthosis to be detachably attached to the user's leg and removed again without damage. A resistance device 40 is attached to the upper part 10, which is supported by the lower part 20 and the upper part 10, and provides adjustable resistance to rotation around the pivot axis 15. Thus, the sensors and control devices previously described in relation to the prosthetic limb embodiment are also present in the orthosis. The original claims are included below. [1] A method for controlling a prosthesis or orthosis of a lower limb having an upper part (10) and a lower part (20) connected to the upper part (10) via a knee joint (1) and pivotably supported relative to the upper part (10) about a joint axis (15), wherein an adjustable resistance device (40) is positioned between the upper part (10) and the lower part (20), the flexion resistance (Rf) is changed via the resistance device based on sensor data, and an axial force (FA) acting on the lower part is detected by at least one sensor (54) and used as a basis for changing the flexion resistance (Rf), a. When the axial force (FA) of the leg chord (70) and / or the extended knee joint (1) decreases, and / or when the position is nearly vertical, the flexion resistance (Rf) is reduced. b. A method characterized in that if knee flexion is not detected within a specified interval, and / or if the knee joint (1) and / or the leg chord (70) and / or the axial force (FA) falls below or exceeds a specific limit value, the flexion resistance (Rf) increases again. [2] The method according to [1], characterized in that the bending resistance (Rf) is reduced when walking from a standing position. [3] The method according to [1] or [2], characterized in that the bending resistance (Rf) is reduced in a manner dependent on a decrease in the axial force (FA). [4] The method according to [1] or [2], characterized in that the bending resistance (Rf) is reduced to a level lower than the stance phase resistance. [5] The method according to any one of [1] to [4], characterized in that the reduction of the bending resistance (Rf) is performed depending on the axial force (FA), the chord angle (αLC) and / or the spatial angle (αS) of the lower part (20). [6] The method according to any one of [1] to [5], characterized in that when the axial force (FA) decreases to a level exceeding a limit value, and when a positive chord angle (αLC) exceeding a limit value, particularly exceeding 5°, is detected, the bending resistance (Rf) does not decrease. [7] The method according to any one of [1] to [6], characterized in that when the axial force (FA) decreases to a level below a limit value, and when a chord angle (αLC) outside a defined angular range around the vertical line (G) is detected, in particular when the positive chord angle (αLC) is greater than 30° and the negative chord angle (αLC) is less than -10°, there is no decrease in the bending resistance (Rf). [8] The method according to [7], characterized in that a complete decrease in the bending resistance (Rf) occurs at positive chord angles (αLC) up to 20°, and the bending resistance (Rf) increases at chord angles (αLC) greater than that, or a complete decrease in the bending resistance (Rf) occurs from a negative chord angle (αLC) of -10°, and the bending resistance (Rf) increases at chord angles (αLC) smaller than that. [9] The method according to any one of [1] to [8], characterized in that no reduction in the bending resistance (Rf) occurs when the axial force (FA) decreases to a limit value, particularly to a level of less than 10% of the patient's body weight, and when an inclination angle (αS) of the lower part (20) with respect to the vertical line (G) is detected within an angular range defined around the vertical line (G), particularly within the range between a positive inclination angle (αS) less than 15° and a negative inclination angle (αS) greater than -5°.

[10] The method according to any one of [1] to [9], characterized in that a complete decrease in the bending resistance (Rf) occurs at a positive inclination angle (αS) of the lower part (20) of 20° or more, and an increase in the bending resistance (Rf) at a smaller inclination angle (αS), or a complete decrease in the bending resistance (Rf) occurs from a negative inclination angle (αS) of the lower part (20) of -10°, and an increase in the bending resistance (Rf) at a larger negative inclination angle (αS).

[11] The method according to any one of [1] to

[10] , characterized in that the flexion resistance (Rf) is increased when an extension movement is performed, a gait cycle is detected, and / or an increase in axial force (FA) is detected.

[12] The method according to any one of [1] to

[11] , characterized in that the bending resistance is not reduced when the backward tilt of the lower part (20) is detected.

Claims

1. A method for controlling a prosthesis or orthosis of a lower limb having an upper part (10) and a lower part (20) connected to the upper part (10) via a knee joint (1) and pivotably supported relative to the upper part (10) about a joint axis (15), wherein an adjustable resistor device (40) is positioned between the upper part (10) and the lower part (20), the flexion resistance (Rf) is changed via the resistor device based on sensor data, and an axial force (FA) acting on the lower part is detected by at least one sensor (54) and used as a basis for changing the flexion resistance (Rf), a. When the axial force (FA) decreases, the bending resistance (Rf) is reduced. b. A method characterized in that if knee flexion is not detected within a specified interval, and / or if the flexion resistance (Rf) increases again, the parameters determined by the position of the knee joint (1) and / or the parameters determined by the position and / or length of the leg chord (70), which is a line connecting an upper point proximal to the joint axis and a lower point distal to the joint axis, and / or the axial force (FA) fall below or exceed a specific limit value.

2. The method according to claim 1, characterized in that the bending resistance (Rf) is reduced when walking from a standing position.

3. The method according to claim 1 or claim 2, characterized in that the bending resistance (Rf) is reduced in a manner dependent on the decrease in the axial force (FA).

4. The method according to any one of claims 1 to 3, characterized in that the reduction of the bending resistance (Rf) is performed depending on the axial force (FA), the chord angle (αLC), and / or the spatial angle (αS) of the lower part (20).

5. The method according to any one of claims 1 to 4, characterized in that when the axial force (FA) decreases to a level exceeding a limit value, and when a positive chord angle (αLC) exceeding a limit value is detected, the bending resistance (Rf) does not decrease.

6. The method according to any one of claims 1 to 5, characterized in that no reduction in the bending resistance (Rf) occurs when the axial force (FA) decreases to a level below a limit value, and when a chord angle (αLC) outside a defined angular range around the vertical line (G) is detected.

7. The method according to claim 6, characterized in that, for positive chord angles (αLC) up to 20°, a complete decrease in the bending resistance (Rf) to a target value occurs, and for chord angles (αLC) greater than that, the bending resistance (Rf) increases, or, from a negative chord angle (αLC) of -10°, a complete decrease in the bending resistance (Rf) to a target value occurs, and for chord angles (αLC) smaller than that, the bending resistance (Rf) increases.

8. The method according to any one of claims 1 to 7, characterized in that when the axial force (FA) decreases to a level below a limit value, and when the inclination angle (αS) of the lower part (20) with respect to the vertical line (G) is detected within an angular range defined around the vertical line (G), the bending resistance (Rf) does not decrease.

9. The method according to any one of claims 1 to 8, characterized in that, at a positive inclination angle (αS) of the lower part (20) of 20° or more, a complete decrease in the bending resistance (Rf) to a target value occurs, and at a smaller inclination angle (αS), the bending resistance (Rf) increases, or, from a negative inclination angle (αS) of the lower part (20) of -10°, a complete decrease in the bending resistance (Rf) to a target value occurs, and at a larger negative inclination angle (αS), the bending resistance (Rf) increases.

10. The method according to any one of claims 1 to 9, characterized in that the flexion resistance (Rf) is increased when an extension movement is performed, a gait cycle is detected, and / or an increase in axial force (FA) is detected.

11. The method according to any one of claims 1 to 10, characterized in that the bending resistance is not reduced when the backward tilt of the lower part (20) is detected.

Images