Method for controlling an orthopaedic knee joint device

Abstract

The invention relates to a method for controlling an orthopaedic knee joint device having an upper part (10) and a lower part (20), which are mounted articulatedly against one another so as to be pivotable about a pivot axis (15), and having an actuator (30), which is coupled to the upper part (10) and the lower part (20) and influences the movement state of upper part (10) and / or lower part (20). The actuator (30) is coupled to a control device (40), which is coupled to at least one sensor (50) and activates, deactivates or modulates the actuator (30) on the basis of sensor values from the at least one sensor (50). The actuator (30) applies an extension moment (τK), which brings about or assists an extension movement with a decreasing knee angle (φK), the applied extension moment (τK) being reduced during the extension movement.

Description

[0001] Method for controlling an orthopaedic knee joint device

[0002] The invention relates to a method for controlling an orthopedic knee joint device having an upper part and a lower part, which are pivotably mounted to one another about a pivot axis. The method comprises an actuator coupled to the upper part and the lower part and influencing a movement state of the upper part and / or lower part. 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 ​​from the at least one sensor. The lower part is designed, in particular, as a lower leg component.

[0003] Orthopedic joint devices include, in particular, orthoses, exoskeletons, or prostheses that comprise an upper part and a lower part articulated to it. In orthoses and exoskeletons, the upper and lower parts are attached to a still-existing limb, for example, using shells, straps, belts, cuffs, or other fastening devices. Orthoses and exoskeletons can guide movements, limit pivoting around a joint axis, prevent pivoting movements, or support or fix the alignment of limbs relative to one another. In polycentric joints, the pivot axis is the instantaneous center of rotation, which shifts depending on the pivoting movement. In addition, orthoses can be equipped with damping devices to dampen pivoting movements around the joint axis.The damping devices can be provided with a control so that, depending on sensor data, a modified damping can be provided in the flexion direction and / or extension direction.

[0004] It is also known to assign mechanical energy storage devices to the upper or lower part, so that movement can be supported by releasing the stored energy from the energy storage device. Mechanical energy storage devices include, in particular, springs, elastomer elements, and pneumatic and hydraulic energy storage devices.

[0005] Prostheses replace a missing or no longer existing limb and serve to provide functionality that is as close as possible to that of the natural limb. Furthermore, prostheses serve to provide the most natural appearance possible for the prosthetic user. A prosthetic upper part is designed, for example, as an osseointegrable component, a prosthetic socket, or as a component attached to a prosthetic socket, where the prosthetic socket serves to secure it to a limb or limb stump. The prosthetic joint, for example a prosthetic knee joint or a prosthetic ankle joint, connects the upper part to a lower part, which in turn may have further prosthetic components, such as a lower leg tube or a prosthetic foot.

[0006] Particularly in orthoses, exoskeletons and prostheses of the lower extremities, but also of the upper extremities, dampers, in particular hydraulic dampers or other resistance devices are arranged between the upper and lower parts. These dampers provide different resistances in individual states or movement situations based on sensor data. Such resistance devices are often designed as linear actuators that provide a defined resistance to a flexion movement and / or extension movement. The resistance is changed, for example, by changing the position of valves. When the flow cross-section is reduced, the corresponding resistance to a movement increases. Passively damped, in particular passively hydraulically damped prostheses or orthoses work purely dissipatively. Energy is taken from the movement of the upper part relative to the lower part, whereby very high moments orForces can be generated. At the same time, passive damping in an open state, for example when no valves are closed or throttles are activated, has only very low resistance. The working range of such an orthosis or prosthesis is limited in that no energy can be fed into the movement in order to support it or actively counteract the movement or to make a change from a static state. In addition, orthoses, exoskeletons and prostheses with motor drives are known from the state of the art, so-called active orthoses or prostheses, in which a movement is initiated, supported or braked by activating, deactivating or modulating the drive. For this purpose, stored electrical energy from a battery or accumulator is converted in the actuator.Motor drives also serve to influence the movement behavior between the components of the orthosis or prosthesis, for example, to slow down a pivoting movement. Motor drives can be operated in braking mode or as part of a generator circuit; they can also be coupled with a mechanical energy storage device.

[0007] Both purely passive devices such as dampers and semi-active devices such as energy storage devices and motor drives influence the movement behavior of the upper and / or lower parts and are actuators that influence a state of motion of the upper and / or lower parts. The actuators can initiate a movement, reverse a movement, assist a movement, or resist a movement. The state of motion of the upper and / or lower parts is also influenced if a load is counteracted, a static state is maintained, or a change in a state of motion due to external forces is prevented or suppressed. This can happen, for example, if a uniform pivoting movement is to be maintained and external forces act in the direction of movement or against the direction of movement.

[0008] EP 2 869 792 B1 discloses a method for controlling an orthopedic joint device of a lower extremity comprising an upper part and a lower part articulated thereto, between which an energy conversion device and / or a storage device is arranged, via which kinetic energy from the relative movement between the upper part and the lower part is converted and / or stored during walking. This energy can be fed back to the joint to support the relative movement, wherein within a movement cycle of the joint device, kinetic energy is converted and / or stored and, within the same movement cycle, is fed back to the joint device in a controlled manner and with a time delay as kinetic energy. The conversion rate and / or storage rate of the energy conversion device or storage device is inversely proportional to the pivoting speed of the lower leg.

[0009] WO 2016 / 169 850 A1 relates to a method for controlling a damping change in an artificial joint of an orthosis, an exoskeleton, or a prosthesis of a lower extremity, comprising a resistance unit between an upper and a lower part, which are pivotally attached to each other. The resistance is changed via a resistance unit when a sensor signal from a control unit associated with the adjustment device activates the adjustment device. The resistance is changed depending on the position and / or length of the leg tendon or its temporal derivatives.

[0010] WO 2016 / 169 848 A1 also relates to a method for controlling a damping change of an artificial knee joint, in which the flexion resistance is reduced during the swing phase. During walking or standing, the course of at least one load characteristic acting on an orthosis or prosthesis to which the artificial knee joint is attached is recorded. If a maximum of the load characteristic course is determined during the stance phase or standing and a threshold value of the load characteristic below the maximum is subsequently detected, the flexion damping during the stance phase is reduced to a swing phase damping level.

[0011] In lower extremity orthopedic devices with an artificial knee joint and an actuator that supports an extension movement, the support of the extension movement can be disruptive in certain situations or even during movement phases. Active support for standing up, stance phase extension when climbing stairs, or lunges, for example, is controlled by detecting moments around the knee axis. A load-dependent change in the extension moment when standing up prevents the user of the orthosis or prosthesis from being lifted uncontrollably or in an unwanted movement sequence. Furthermore, the mechanical components of the artificial knee joint are subjected to considerable stress.

[0012] The object of the present invention is to provide a method for controlling an orthopaedic knee joint device which enables the user to use the orthopaedic device comfortably and safely.

[0013] This object is achieved by a method having the features of the main claim. Advantageous embodiments and further developments of the invention are disclosed in the subclaims, the description, and the figures.

[0014] The method for controlling an orthopedic joint device having an upper part and a lower part that are pivotably mounted to one another about a pivot axis, with an actuator that is coupled to the upper part and the lower part and influences a state of movement of the upper part and / or lower part, wherein the actuator is coupled to a control device that is coupled to at least one sensor and activates, deactivates, or modulates the actuator based on sensor values ​​from the at least one sensor, provides that an extension moment is applied by the actuator, which causes or supports an extension movement with a decreasing knee angle and that the applied extension moment is reduced with a decreasing knee angle. The decrease or reduction of the applied extension moment coincides with the knee extension movement.To reduce the extension moment caused by the actuator, it is not necessary to measure the knee angle; it is sufficient if a knee extension movement is inferred or if this movement is present. This method achieves harmonious support for the extension of an artificial knee joint, for example, during stance phase extension, such as when walking upstairs, standing up, or during similar movements in which an active extension or extension moment is applied. The application of an extension moment by the actuator is achieved, for example, by extending a hydraulic actuator by activating a pump, pumping hydraulic fluid into a hydraulic chamber, and extending a piston rod from a housing.An extension moment can also be applied via rotary hydraulics, in which an extension chamber is pressurised with hydraulic fluid in order to cause or support a twisting movement in the extension movement. Alternatively or additionally, other drives or energy storage devices can be activated in order to generate forces or moments with which an extension movement is initiated or at least supported. The actuator causes a corresponding load or force introduction into the upper and lower parts. If an extension movement is detected while an extension moment or a corresponding force that causes or supports an extension movement is applied - an extension movement occurs when the knee angle decreases - the extension moment or force is transmitted.the force applied by the actuator is reduced so that, at least in part or phase of the extension movement, with increasing extension of the knee joint, the assisting force from the actuator is reduced and the assisting force is reduced. The knee angle is assumed to be minimal or 0 when the knee joint has reached maximum extension. This is the case, for example, when a lower leg can no longer be moved in the direction of extension relative to the thigh. The limitation of the extension movement can be set by a mechanical extension stop and / or a hydraulic extension stop. By reducing the extension moment applied by the actuator, rapid stops and abrupt braking of the joint towards the end of the extension movement can be avoided.The knee joint is thus not supported or additionally supported towards the end of the extension movement, resulting in a harmonious movement and, in particular, a slow or delayed achievement of maximum extension. Towards the end of knee extension in a standing position, the continued extension movement no longer leads to a significant elevation of the body's center of gravity, but merely to a backward movement of the knee joint axis, which leads to excessively rapid extension of the knee until the extension strike. This procedure prevents this.

[0015] In one embodiment, the applied extension moment is only applied after a specified starting knee angle has been reached, or the applied extension moment is only reduced after a specified knee angle limit has been reached. This means, for example, that when standing up, the initially applied extension moment is maintained over an angular range in which extension and thus a reduction in the knee angle occurs. Only when a limit angle is reached, i.e., a position extended compared to the starting position, is the applied extension moment reduced as the knee angle continues to decrease. The limit knee angle can, for example, be between 60° and 15°. Alternatively or additionally, extension support only occurs above a specified starting knee angle.The respective knee angle from or up to which activation, deactivation or modulation takes place can be changed depending on the respective situation, so that a different starting angle or knee angle limit can be set for standing up than for climbing stairs.

[0016] In one embodiment, the extension moment is only applied up to a specified limit knee angle before reaching a stroke, to ensure that no supporting forces or moments are applied by the actuator for the final adjustment path before reaching the extension stop, i.e., the set end position of the upper part relative to the lower part. This prevents a situation where, instead of a lifting of the body's center of gravity, there is merely a displacement of the lower leg relative to the thigh in the extension direction, which, when walking in the stance phase, usually means a displacement of the pivot axis opposite to the walking direction. This prevents an unbraked or even accelerated impact into the extension stop. The limit knee angle can be adjusted depending on the situation.

[0017] In one embodiment, after a reduction in the extension moment before the extension stroke is reached, a resistance moment is applied which counteracts the extension movement. This not only prevents an accelerated movement into the extension stroke, but also reduces the assisted extension movement. The resistance moment can be applied either by converting kinetic energy into another form of energy, e.g. heat, or by a semi-active or active drive, so that a moment counteracting the extension movement is applied around the pivot axis. In one embodiment, the extension moment is changed depending on the position of the upper part, the position of the lower part and / or the position and / or length of a leg tendon or a change in one of the variables or parameters. The condition or conditions with regard to the position of the upper part or the lower part ora parameter that is characterized by a geometric relationship between known dimensions of the upper and lower parts, or changes to these, prevents support for an extension movement in situations that could be uncomfortable for the patient or user of the artificial knee joint. In a kneeling position, with the treated leg stretched backwards and the thigh approximately vertical, but the lower leg almost horizontal, an active extension movement could lead to the knee joint being extended from this position, which could possibly lead to the treated leg being fully extended and placed in a position that is uncomfortable for the user, or such a movement is supported. This is prevented by recording the position of the upper part, the lower part and / or the leg tendon or the length of the leg tendon. The spatial position of the upper part orof the lower part can be determined using at least one inertial sensor or several inertial sensors, spatial position sensors or an IMU (inertial measurement unit); the length of a leg tendon is determined via the position of the upper and lower parts in relation to each other, given known or estimated lengths of the upper and / or lower parts. The lengths can be estimated or derived from anthropometric proportions if one of the lengths is stored, measured or recorded or determined in some other way in the controller. The leg tendon is determined, for example, from a fixed point on the lower part, for example an ankle joint axis or a frequent contact point of a prosthetic foot or prosthetic footplate with the ground, and a reference point on the upper part, for example the proximal end point in the area of ​​the hip joint.The position of the leg tendon and the change in position of the leg tendon is determined, for example, from the position information about the lower part in conjunction with an angle sensor to determine the relative angle between the upper and lower parts or from the position information of the upper part and lower part via two position sensors.

[0018] In one embodiment, the extension moment is changed depending on the size, point of application and / or orientation of the ground reaction force. The point of force application on the foot, for example a prosthetic foot, a footplate or a natural foot, the orientation of the ground reaction force vector as well as lever arms around ankle joint axes, pivot axes in the knee joint or hip axes or even moments around the axes can be used for control. For this purpose, one or more moments or forces are measured, for example the ankle moment, the knee moment and / or an axial load, in order to determine the ground reaction force vector completely, when viewed in the sagittal plane. A change, in particular a reduction of the extension moment is necessary in particular when the external flexion moment around the pivot axis in the knee joint decreases, if this moment is already low or if an extension moment is applied externally.An extension moment applied by the actuator would then support an undesired movement. If the ground reaction force vector is located far behind the pivot axis, a high flexion moment is typically applied, especially in combination with a high load on the prosthesis, so that support from an extension moment of the actuator may be necessary. If the ground reaction force vector is positioned in front of the pivot axis in the walking direction, an external extension moment is present, which means that the actuator usually does not need to be activated further to apply an additional, internal extension moment. In such a case, the external extension moment is usually sufficient to cause an extension movement.

[0019] In one embodiment, the magnitude and orientation of the ground reaction force are determined from the axial force acting on the lower part, a knee moment acting around the knee joint, and a moment acting on the lower part, in particular a moment acting in the sagittal plane. The moment acting in the lower part or lower leg section is, for example, an ankle moment, in particular an ankle moment acting around an ankle joint axis, but can also be a moment acting in the distal third of the lower part. If a moment acting on the lower part, in particular in the sagittal plane, is detected which, in the event of an effective axial force in the direction of the pivot axis, i.e. with a planted foot, indicates dorsiflexion, for example because the body's center of gravity lies in front of the ankle joint axis, an increased extension moment is provided in a further development.Conversely, if an ankle moment acting in the plantar flexion direction or a moment acting on the lower part in the sagittal plane is detected, it may be useful to avoid or reduce extension support in order to initially facilitate or allow flexion until a lifting of the body's center of gravity and an extension moment are desired and necessary.

[0020] In one embodiment, the extension moment is varied depending on the position of the pivot axis and / or a joint axis relative to a foot section arranged on the lower part. If the pivot axis is located anterior or posterior to the foot section, higher or lower extension moments can be applied; the same applies to the hip joint axis.

[0021] In one embodiment, the extension moment is only applied if the spatial position of the upper part, the lower part, and / or the leg tendon is within specified limits. For example, no extension moment should be applied when kneeling, even if knee extension is detected. Therefore, the limit value, for example, must be the spatial position of the lower part or lower leg beyond the horizontal, for example, 45° to the horizontal. The spatial position of the leg tendon can also be crucial, for example, if a prosthesis or orthosis user is in a lying position or the orientation of the treated side is otherwise identified as not being upright.

[0022] In one embodiment, the actuator is designed as a drive, in particular as an electric motor, in particular in combination with a gear, e.g. a spindle gear, gear transmission or traction mechanism transmission, or as a drive connected to a mechanical energy storage device or has at least such a drive and a resistance device, which are each activated, deactivated or modulated by the control device in order to influence the extension behavior of the knee joint.

[0023] In one embodiment, the extension moment is varied depending on the speeds and / or accelerations of the upper part, the lower part, a foot part, and / or the leg tendon in order to account for dynamic processes in the change in the applied extension moment. From the individual speeds or accelerations, movement situations or conditions can be determined or inferences can be drawn about specific situations in which extension moments are applied or changed when knee extension is detected. If an increased forward speed is present, a higher extension moment can be applied, and if a lower forward speed is present, a lower extension moment can be applied.

[0024] In one embodiment, with the lower leg tilted forward in the walking direction, the extension moment is increased or not decreased until the knee angle reaches a predetermined limit. The extension moment can then be reduced and, if necessary, reversed. The forward inclination of the lower leg is positively correlated with the magnitude of the applied extension moment. The further the lower leg or lower leg is tilted forward, the greater the applied extension moment.

[0025] In one embodiment, the extension moment is reduced if the lower leg or lower leg exhibits insufficient forward tilt or rotates backward, counter to the walking direction. The backward rotation of the lower leg is detected via an angle sensor in the ankle joint and / or an IMU, possibly via the leg tendon. Conversely, the extension moment can be increased after initial contact during loading and a relative forward rotation of the lower leg.

[0026] A positive correlation of the extension moment can occur with an axial force acting on the lower leg or the lower part; the greater the axial force, the greater the extension moment, provided that a flexion moment around the pivot axis is generated due to the axial force.

[0027] In one embodiment, the extension moment is positively correlated with the position of the force application point of the ground reaction force and / or a moment about the ankle axis during forward rotation and / or changes therein. The further the force application point is shifted backward, the greater the flexion moment effective about the pivot axis, so that an increase in the extension moment applied by the actuator is sensible. The same applies to an ankle moment that counteracts forward rotation about an ankle joint axis. The force application point can be used as an indicator which, together with the characteristics of the prosthetic foot (active or passive), allows conclusions to be drawn as to whether and to what extent the external knee moment is flexing or extending. The characteristics of a prosthetic foot are determined, for example, by whether it is an active or passive prosthetic foot.In passive feet, the entire system of lower leg and foot typically rotates across the ground. As the force application point shifts from the middle of the foot to the forefoot, the extensor knee moment may initially increase, then decrease again and change to a flexor moment.

[0028] In one embodiment, the extension moment is varied depending on the relative position of the body's center of gravity, torso, hip joint, and / or knee joint to the foot and / or the foot section. In particular, the horizontal component of the relative positions can be used. The relative position of the knee joint and hip joint can be determined, for example, using one or more relative and / or absolute angle sensors. The relative position of the hip joint to the foot can be determined, for example, using a lower leg angle in space, a knee angle, and the length of the lower leg and thigh.

[0029] In one embodiment, the extension moment in at least one movement phase is positively correlated with the forward displacement and / or negatively correlated with the backward displacement of the knee joint axis. A greater forward displacement relative to the foot or foot section increases the extension moment. A forward displacement of the knee joint relative to the foot section indicates a higher external flexion moment. Accordingly, a supporting extension moment can be increased without causing the knee joint to snap.

[0030] In one embodiment, the extension moment is reduced during knee extension when standing up, climbing stairs and / or during the stance phase extension of walking on level ground or on different inclines. In these movement situations in particular, it is advantageous if snapping of the knee joint during knee extension is prevented and harmonious knee extension occurs instead. In one embodiment, the reduction in the extension moment depends on the movement situation, the movement phase and / or a mode of the orthopedic device. For example, the reduction in the extension moment can be controlled differently when standing up than when climbing stairs in order to optimally adapt the movement sequence and support to the respective movement situation. In other movement situations, it is advantageous not to reduce the extension moment during an extension movement.It is also possible that the type of reduction is controlled differently in an early movement phase, such as the landing phase, than in a later movement phase, for example, when the body weight has already been shifted to the treated side. In special modes, such as for performing specific activities or sports, but also when the functionality of the orthopedic device is limited, the reduction of the extension moment can be specifically adapted to the mode or not performed at all. The reduction can also be individually adapted to the user or permanently deactivated, for example, via a smartphone app that communicates with the orthopedic device.

[0031] The described embodiments can also be combined with others. This can involve the overlaying of different control methods. For example, the described control methods can be combined with control via a human-machine interface, which allows users to intentionally or involuntarily influence the control, for example, by reducing, increasing, or modulating the extent of the extension moment. One embodiment of a human-machine interface is a device for recording muscle activity, for example, via EMG sensors, which makes this information available to the orthopedic device.

[0032] In one embodiment, the extension moment is applied by generating or emulating system elasticity and / or damping. The elasticity and / or damping can be non-linear and / or variable over the course of the movement depending on the movement phase and / or determined variables. The elasticity and / or damping can be emulated by an actuator, e.g., by an electromechanical actuator such as an electric motor. The change in elasticity and / or damping can depend in particular on the position of the at least one lower and / or upper part, the relative position of components to one another, the ground reaction force or components thereof, moments, forces, and / or lever arms, as well as their change over time. A reduction in an extension moment during knee extension can be achieved by means of elasticity that positively correlates knee flexion and extension moment.Such elasticity can also be used to increase the extension moment during knee flexion. The elasticity can be designed so that only an extension moment is generated, and no flexion moment is applied when the moment zero point is reached or exceeded.

[0033] In one embodiment, the extension movement is stopped before reaching the extension stop, and thus at a knee angle greater than 0. This can be achieved, in particular, by locking a hydraulic damper or a magnetorheological damper as part of the actuator in the extension direction.

[0034] In one embodiment, for climbing stairs and / or standing up, a free flexion of the knee joint is set or a flexion resistance is reduced and then the extension movement is supported by the actuator.

[0035] Exemplary embodiments of the invention are explained in more detail below with reference to the figures. They show:

[0036] Figure 1 - a schematic representation of a prosthetic leg;

[0037] Figure 2 - a schematic representation of a leg orthosis;

[0038] Figure 3 - a first movement sequence when standing up;

[0039] Figure 4 - a schematic representation of the reduction of an extension moment;

[0040] Figure 5 - another movement sequence when standing up;

[0041] Figure 6 - a movement sequence when overcoming several steps; Figure 7 - a control of the extension moment as a function of the ground reaction force;

[0042] Figure 8 - different leg positions during a knee extension movement;

[0043] Figure 9 - different leg positions and body positions when climbing on a step

[0044] Figure 10 - Representations of lower leg inclination, leg tendon and foot position;

[0045] Figure 11 - a relationship between the lower leg inclination and force application point on the prosthetic foot during a rolling movement

[0046] Figure 12 - a curve of knee angle, lower leg angle and extension moment;

[0047] Figure 13 - another course of knee angle, lower leg angle and extension moment;

[0048] Figure 14 - Courses of knee angle and extension moment for different movement speeds;

[0049] Figure 15 - Courses of knee angle and extension moment for different controls via a biosignal;

[0050] Figure 16 - Courses of force and angle quantities as well as the extension moment;

[0051] Figure 17 - a relationship between several parameters and the extension moment;

[0052] Figure 18 - a kneeling position; and

[0053] Figure 19 - an extreme position.

[0054] Figure 1 shows a schematic representation of a prosthetic knee joint as part of a prosthesis, and Figure 2 shows an orthotic knee joint as part of an orthosis. The prosthetic knee joint has an upper part 10 and a lower part 20, which are pivotally mounted on one another about a pivot axis 15. In a design as a prosthesis, a prosthetic foot 60 is arranged at the distal end of the lower part 20. In the design of the artificial knee joint as an orthotic knee joint, as shown in Figure 2, the lower part 20 is designed as a lower leg splint on which no foot part is arranged, but on which an optional foot part 60 can be arranged, represented by a broken line. In the case of a KAFO (knee ankle foot orthosis), a foot part 60 is arranged on the lower part 20, on which a foot can be placed. However, this can also be omitted to create a pure knee orthosis.In the embodiment as a prosthetic leg according to Figure 1, a prosthetic socket or other device for receiving a femoral stump or for securing it to a person is arranged or formed on the upper part 10. In the embodiment according to Figure 2, the orthosis is secured to a leg via fastening means 101, 201, which are designed, for example, as straps, shells, or the like, in order to removably secure the orthosis to the leg.

[0055] An actuator 30 is arranged as a linearly acting hydraulic actuator between the upper part 10 and the lower part 20. In the illustrated embodiment, the hydraulic actuator 30 is designed with a hydraulic chamber or a cylinder that is arranged or formed in a housing or base body 31. A piston 32 is displaceably mounted in the cylinder. The piston 32 is displaceable along the longitudinal extent of the cylinder and is fastened to a piston rod 33 that protrudes from the housing or base body 31. The piston 32 divides the cylinder into chambers that are fluidly connected to one another via at least one hydraulic line. The base body 31 or the housing can be pivotally mounted on the lower part 20 at a fastening point 23 in order to prevent canting of the piston 32 during a pivoting movement of the upper part 10 relative to the lower part 20.The end of the piston rod 33 facing away from the piston 32 is attached to the upper part 10, in the illustrated embodiment to an extension arm to increase the distance from the pivot axis 15, at an upper attachment point 21. During flexion, the piston 32 is pressed downward, so that the volume of an extension chamber decreases. Correspondingly, the volume of a flexion chamber increases, reduced by the volume of the retracting piston rod 33. An electric motor 36 can be arranged in or on the housing 31 to generate pressure within one of the chambers. This electric motor drives a pump 37 to apply pressure to the hydraulic fluid within one of the two chambers and thereby move the piston 32 within the cylinder in one direction or the other. This causes a flexion movement or, in particular, an extension movement of the orthopedic device in the form of the prosthetic leg.The electric motor 36 for driving the pump 37 is an option that can be used in one embodiment in combination with the linear damper. An alternative design of the actuator provides a rotary hydraulic system or an electric motor, e.g., with a gear, instead of a linear hydraulic system. A combination of several of the aforementioned actuators in conjunction with passive resistance devices is also implemented in one embodiment.

[0056] Arranged within or on the housing 31 is an adjustment drive 34, which is coupled to at least one control valve 35, via which the hydraulic resistance in the linear hydraulic system 30 can be varied if the resistance is to be controlled during use via hydraulic damping. The adjustment drive 34, like the entire actuator 30 with the motor 36, is coupled to a control device 40, which, based on sensor values, activates, deactivates, or modulates the actuator 30, and in particular the motor 36 and the adjustment drive 34, in order to provide adapted resistance and hydraulic support for an extension movement and, if necessary, a flexion movement.If the resistance device is not designed as a hydraulic damper but as a magnetorheological resistance device, the change in the resistances is not achieved by adjusting valves 35, but by activating, deactivating or modulating a magnetic field, the adjustment drive 34 is then the electromagnet or the magnetic coil.

[0057] At least one sensor 50 for detecting the spatial orientation of the lower part 20 and the upper part 10, respectively, is arranged on both the upper part 10 and the lower part 20. In particular, the sensor 50 for detecting the spatial orientation is arranged only on the upper part 10. This sensor 50, which can be designed, for example, as an IMU (inertial measurement unit), is used to determine the solid angle or the absolute angle to a fixed spatial orientation, for example, the direction of gravity, during use of the prosthetic knee joint or the orthotic knee joint. Instead of being designed as an IMU for detecting spatial positions, the sensor 50 can also detect other status data, in particular status data relating to the artificial knee joint. Another sensor 50 is schematically shown as a hexagon and is designed as a human-machine interface (MMI) sensor for recording human biosignals.When used in a prosthesis, this is preferably attached to the upper part 10 in order to interact with the body. When designed as an orthosis, the MMI sensor can also be arranged on other components. In principle, an MMI sensor can also be attached separately to the body and wirelessly coupled to the control device 40, e.g., via a radio connection. The status data recorded includes, in particular, positions, angular positions, speeds, accelerations, forces, moments, as well as their progressions or changes. The determined solid angle of the upper part 10 and / or the lower part 20 or another status variable is compared with a threshold angle.When a threshold value stored in a controller 40 for the respective sensor value or a variable derived therefrom is reached or exceeded, the adjustment drive 34 and / or the motor 36 is modulated, activated or deactivated in order to change the flow resistance in the hydraulic system and the support force in the extension direction by the motor 36 and the pump 37 in the actuator 30 in the design as a hydraulic actuator, the viscosity in a magnetorheological design and the drive torque or the braking force in an electromechanical drive.

[0058] The actuator 30 in an artificial knee joint serves to modulate a flexion movement and an extension movement in order to generate or support an appropriate or desired movement sequence. An extension movement is supported if necessary and advantageously decelerated shortly before reaching maximum extension to avoid a hard stop. In order to be able to drive the actuator 30, in particular the motor 36 and, if applicable, the adjustment drive 34, an energy storage device, in particular in the form of an accumulator, is also assigned to the actuator 30. The energy storage device can be arranged directly next to the actuator 30 or at another location in the orthopedic device where more space is available or where this appears advantageous due to the weight distribution.

[0059] One difference between the embodiment according to Figure 1 and the embodiment according to Figure 2 is that, according to Figure 2, an electromechanical drive with a motor 36 is provided, in which the electric motor 36 can apply a torque between the upper and lower parts, if necessary via a gear, in particular a force-locking or form-locking traction mechanism. Depending on the direction of rotation of the motor 36, flexion or extension of the knee joint can then be effected or supported via, for example, a V-belt or toothed belt and pulleys. The embodiment with the drive with an electric motor 36 via a mechanical power transmission device and parallel damping via a hydraulic damper can also be used in a prosthetic knee joint. As already explained in relation to Figure 1, the resistance device in an orthosis can also be implemented as a motor, e.g. in generator mode.

[0060] The direct mechanical coupling of the electric motor 36 as part of the actuator 30 to the upper part 10 and the lower part 20 can be achieved via a power transmission device, for example via a spindle drive, so that instead of a piston rod 33, a spindle is retracted or extended from the housing 31 by turning a spindle nut driven by the electric motor. Alternatively, the spindle can be coupled to the motor and move the spindle nut translationally and support a bending and / or stretching movement. In another embodiment, the motor 36 is coupled to the upper part 10 and the lower part 20 via a gear device, for example via a planetary gear, in order to effect or decelerate a displacement of the upper part 10 relative to the lower part 20. The gear device can have a variable transmission ratio.

[0061] Furthermore, the prosthesis or orthosis is provided with a control device 40 and at least one angle detection device in the form of a sensor 50. The angle detection device 50 detects the angle between the upper part 10 and the lower part 20 and is designed, for example, as a direct angle sensor that detects the angle directly. Alternatively, the angle between the upper part 10 and the lower part 20 can be determined by evaluating the sensor data from two spatial position sensors 50. Both methods can also be used simultaneously or in a complementary manner. All sensors arranged on the prosthesis or orthosis are coupled to a control device 40, and their sensor values ​​serve as the basis for controlling the actuator 30, in particular the motor 36 and the adjustment drive 34 of a resistance device if this is designed as a passive damper, or as input signals for a motor control system.In the case of magnetorheological damping, the sensor values ​​serve to control the magnetic field or its variation. Based on the sensor data, in particular the spatial and / or angular positions as well as position data and data on the load, orientation, acceleration, and / or deformation of other components, the actuator 30 is controlled, for example, to activate, deactivate, or modulate the electric motor 36, to generate or support a relative movement between the upper part 10 and the lower part 20, in particular to apply an extension moment in a controlled manner, but also to reduce or increase a pivoting resistance and / or to limit an end stop.

[0062] Figure 3 shows a first movement sequence for standing up from a sitting position in four states t0 to t3. In the exemplary embodiment, the user uses a prosthetic leg with an upper part 10 in the form of a femoral shaft, a lower part 20 which is pivotally mounted on the upper part 10 about the pivot axis 15, and a prosthetic foot 60 which is also pivotally mounted on the lower part 20 about a pivot axis, namely the ankle joint axis 65. At time t0, the user is in a sitting position. To stand up, particularly when there is no support from the arms, the torso is usually tilted forward in order to shift the body's center of gravity forward. In addition, hip extension and, if necessary, knee extension are effected by the non-supported leg, so that the body is lifted from the seat surface, which is shown at time t1.This results in a reduction in the knee angle cpK, which is measured between the longitudinal extension of the lower part 20 and the longitudinal extension of the upper part 10. The knee angle cpK decreases when the knee joint is extended and is 0 when the prosthetic leg is fully extended. The knee angle cpK is either the angle included between the longitudinal extension of the upper part 10 and the extension of the longitudinal extension of the lower part 20 that extends beyond the pivot axis 15, or the complementary angle, i.e. the angle included between the longitudinal extension of the lower part 20, which passes through the ankle joint axis 65 and the pivot axis 15, for example, and the extension that extends proximally from the pivot axis 15.The degree of support for lifting the body by the actuator 30, which is not shown in Figure 3 but is designed according to one of the variants described above, is controlled in particular via the knee joint angle cpK.

[0063] After the body is bent forward and the body weight is at least partially shifted to the prosthesis side, a concentric extension movement around the pivot axis 15 is generated. In the illustrated embodiment, this only occurs once a specified starting knee angle cpKs is reached, from which an extension moment is applied. The size of the starting knee angle cpKs can vary and be determined depending on the situation. The starting knee angle cpKs can be determined, for example, based on the detected movement and / or loading situation. After support begins through an extension moment applied by the actuator 30, the knee joint is further extended, so that the knee angle cpK decreases. The user's center of gravity is raised until a limit knee angle cpKe is reached, which is shown in Figure 3 at time t2.This limit knee angle cpKe is significantly smaller than the starting knee angle cpKs and occurs before reaching a point of extension, which is characterized by the fact that no further extension movement of the upper part 10 relative to the lower part 20 can occur. The limit knee angle cpKe can, for example, be set from 10° to 5° before reaching an extension stop. The size of the limit knee angle cpKe can vary and be set depending on the situation. The limit knee angle cpKe can, for example, be set based on the recognized movement situation and / or load situation and, for example, can be shifted towards a smaller limit knee angle cpKe at a high movement speed. After reaching the limit knee angle cpKe, a further reduction in the knee angle cpK reduces the applied extension moment to a very low level or interrupts support for an extension movement.To prevent the upper part 10 from hitting an extension stop during an extension movement, it is also possible to apply resistance counteracting extension after reaching the limit knee angle cpKe, either by braking using a passive resistance device, for example, a hydraulic damper, a magnetorheological damper, or a friction brake, or by reversing the direction of action of the actuator 30 and actively applying a moment acting in the direction of flexion. The terminal knee extension, from reaching the limit knee angle cpKe until reaching full extension at time t3, is thus braked harmoniously.The extension moment can also be reduced during knee extension before the limit knee angle cpKe is reached, for example between times t1 and t2 in Figure 2, in particular depending on the knee extension movement, determined via the knee angle, so that when the knee angle is reduced, the extension moment is also reduced.

[0064] Instead of controlling exclusively via the knee angle cpK, the application of an extension moment can also be initiated based on other parameters, or additional parameters must be met for the extension moment to be applied. The additional parameters can be, for example, the orientation of the upper part 10 and / or the lower part 20 in space or relative to each other, load parameters of the foot part 60, a spatial position of the leg tendon 70, and / or an orientation of the leg tendon 70.

[0065] Such a method makes it possible to harmoniously support the extension movement of a leg fitted with an orthopedic device, prevent the knee joint from snapping towards the end of the extension movement, and avoid extension in orientations of the fitted leg where the application of an extension moment is unfavorable or undesirable. During knee extension, particularly after reaching a limit knee angle, the extension moment is reduced and / or controlled via additional parameters such as ground reaction force vector, lower leg angle, leg tendon angle, and / or orientation of the individual components or the leg tendon in space so that the lower part 20 does not snap backward, but rather the extension moment is optimally used to raise the body's center of gravity.

[0066] Figure 4 shows two embodiments of a reduction in the extension moment TK as a function of the knee angle cpK over time. In the upper illustration, once a knee angle limit value cpKf is undershot, the extension moment TK is continuously reduced with knee extension until a specified limit knee angle cpKe is reached. The knee angle limit value cpKf is set, for example, between 60° and 30°, and the limit knee angle cpKe between 10° and 5° before the extension stop is reached. After the limit knee angle cpKe is reached at time t2, the supporting extension moment is reduced to a low level. In the lower illustration, an extension moment supporting the knee extension movement is only applied when a starting knee angle cpKs is undershot at time t1. The moment is preferably not applied suddenly, but rather with a harmonious transition.Once the knee angle falls below a certain threshold value cpKf, the extension moment is reduced with the knee extension movement. The reduction of the extension moment is designed such that, by the time t3 when the limit knee angle cpKe is reached, the extension moment has already been completely reduced. When the limit knee angle cpKe is fallen below, instead of a supporting extension moment TK, a moment counteracting the extension movement is applied. This moment is designed as a flexion moment and thus has a negative sign. Alternatively, the extension moment TK is not completely reduced, and accordingly, no resistance is applied to further extension movement at a small knee angle cpK. A combination of the described processes is also possible.

[0067] Figure 5 shows a further movement sequence for standing up from a sitting position in four states t0 to t3. At time t0, the person is in a sitting position and the prosthesis is not or only slightly loaded. To stand up, the body weight is transferred to both legs. In order to shift the body's center of gravity over the feet, the upper body is tilted forward. In the movement sequence shown, the pivot axis 15 is also moved forward from the starting position at time t0 in Figure 5, and thus the body's center of gravity is shifted towards the foot part 60, in particular the middle of the foot or the forefoot of the foot part 60, as shown at time t1.During this initial forward movement, knee extension movement via the hip or the contralateral knee is typically not initiated; instead, the prosthesis is essentially intended to assume the load and enable favorable positioning of the body for the subsequent knee extension. The forward displacement increases the external knee flexion moment, and the degree of support in knee extension can be increased without the knee joint snapping. This is achieved by initially applying an extension moment that does not yet initiate knee extension movement. The extension moment can be generated partially or completely by the motor drive of the actuator 30. For example, it is possible to control the extension moment generated by the drive such that the knee angle is initially kept constant or no knee flexion occurs.The extension moment can also be applied by a resistance device that is part of the actuator 30, for example, a hydraulic damper that has a high flexion resistance or is locked in the flexion direction. A force accumulator can also be used as part of the actuator 30 to apply an extension moment. A superposition of these elements is also possible, for example, hydraulic damping and a drive torque from a motor. Initially, knee flexion can also be permitted against an extension moment. Additionally, the extension moment can be increased, particularly with increasing knee flexion. This makes it possible to achieve a stable balance between external and internal knee moments and prevent excessive knee collapse.The extension moment can be applied, for example, when, starting from a sitting position, a load on the prosthetic side, a knee movement, a forward movement, and / or a corresponding position of the prosthetic components relative to one another is detected. In order to enable a particularly high degree of forward movement and to push the knee axis 15 as far as possible over the forefoot of the foot part 60, dorsal extension can be permitted in a movable ankle joint, for example a mechatronically controlled ankle joint, as shown at time t0 in Figure 5. Assistance for the knee extension movement can occur as soon as knee extension is detected, which is initiated by the person extending the hip or extending the knee on the contralateral side. The extension moment can then be adjusted so that harmonious knee extension is achieved.

[0068] Furthermore, the control of the extension movement, the extension moment, or a modulation of the extension movement or the extension moment can be carried out depending on the position of the lower part 20, the upper part 10, the relative position of the foot part 60 to the body or parts of the orthopedic device, the relative position of the knee axis 15 to the body or parts of the orthopedic device, or even the position and orientation of a leg tendon 70, as well as the temporal change of these variables. The leg tendon 70 is shown in the third illustration from the left in Figure 5 and is the connecting line between a reference point on the foot part 60 or the lower part 20 and a reference point on the upper part 10, for example, the hip joint axis 25. The reference point on the lower part 20 or the foot part 60 can, for example, be the ankle joint axis 65 or a force application point of a ground reaction force on the foot part.The position of the lower part 20 as an inclination angle <pS kann beispielsweise die Orientierung des Unterschenkels im Raum, insbesondere in Bezug auf das Schwerkraftfeld, wie in der Figur 5 in der zweiten Darstellung von links dargestellt, oder in Relation zur Umgebung, wie in der dritten Darstellung von links dargestellt, sein. Letztere kann beispielsweise über einen Knöchelwinkelsensor ermittelt werden. Auch die Lage des Oberteils 10 oder der Beinsehne 70 kann im Raum oder gegenüber der Umgebung ermittelt werden. Die Lage kann beispielsweise über eine oder mehrere IMUs, gegebenenfalls in Kombination mit einer oder mehrere Relativwinkelsensoren, bestimmt werden. Insbesondere die Lage in der Sagittalebene kann für die Steuerung herangezogen werden.

[0069] The extension moment can be changed depending on the lower leg angle. For example, an extension moment can be increased with increasing forward inclination or forward rotation of the lower leg. In a first forward movement, the lower leg is rotated forward from the starting position, shown at time t0 in Figure 5, for example to a position as shown at time t1. The extension moment can initially be controlled in such a way that flexion of the knee joint is prevented or a controlled flexion against a resistance occurs so that the treated side can be loaded. With forward rotation and / or increasing forward inclination, the extension moment is increased. By increasing the extension moment, an extension movement can be initiated depending on the lower leg inclination and / or rotation speed, if necessary in combination with a hip extension movement by the user.With a greater forward inclination of the lower leg, there is typically a higher external, knee flexion moment, which allows for greater support of the knee extension movement without the knee joint snapping. Even with a faster forward movement or forward rotation, the knee extension moment can be increased due to the dynamics and inertia of the body and the components of the orthopedic device. For example, the extension moment provided by a motor drive can be increased once a first threshold value of the forward inclination of the lower leg is exceeded, in particular it can be correlated with the forward inclination of the lower leg. The threshold value of the forward inclination of the lower leg and thus also the extent of the correlation can depend on the situation and / or other parameters, e.g. the initial situation, the load or the speed of movement.

[0070] During the extension movement from the slightly raised position, as shown in Figure 5 at time t1, to full extension as shown in Figure 5 at time t3, the extension moment can be controlled depending on the position information of one or more components. The extension movement is controlled in particular in such a way that the lower leg does not rotate backward quickly and the knee axis does not move quickly posteriorly. The extension moment can, for example, be positively correlated with the lower leg inclination, so that the extension moment is reduced as the forward inclination decreases. Figure 5 shows an intermediate position at time t2 in which the knee joint is already partially extended, but the lower leg is still strongly bent forward and the knee axis is above the forefoot.By positioning the treated leg in this way, actuator-assisted knee extension can raise the body's center of gravity. Furthermore, the extension moment can be reduced by decreasing the forward speed and / or forward rotation speed of the lower leg. For example, during the forward movement from time t0 to t1, during which rotation around the foot section occurs, a certain forward speed exists, which slows down or even reverses during extension between time t1 and t2. Accordingly, the extension moment can be reduced during this phase.In particular, when the forward tilt and / or forward rotation of the lower leg falls below a threshold value and / or when reverse rotation of the lower leg begins, the extension moment can be completely reduced or a flexion moment can be applied to counteract knee extension. Such a reverse rotation is shown in Figure 5 between the times t2 and t3 shown. In such a late phase of knee extension, a harmonious attainment of the extension position is achieved and rapid snapping through is prevented. The extension moment and / or the extension resistance can also be adjusted so that a defined position and / or a certain temporal change in the position is achieved or not exceeded.Alternatively or in addition to the lower leg inclination and rotation, the position and change in position of the upper part, the leg tendon and / or one or more components of the orthopedic device in relation to the body or to one another can also be used for control in a similar way. For example, the extension moment can be changed depending on the position or change in position of the leg tendon. The position of the leg tendon provides information about the relative position of the hip or torso above the foot. For example, an extension moment can be reduced once the leg tendon exceeds a certain forward or backward inclination, or increased once a certain forward or backward inclination is exceeded. This can prevent a high degree of extension support from occurring even though the foot part is not underneath the body, which typically creates a tipping moment around the body forwards or backwards.pushes the body forward or backward and can lead to loss of balance. Such a control, for example, applies a particularly high extension moment in the position shown in Figure 5 at time t2, where the leg tendon is approximately vertical. In addition, other parameters can also be used for control, such as relative angle, force, and / or moment information.

[0071] Figure 6 depicts a movement sequence when negotiating one or more steps, with the basic movement sequence being analogous to standing up as shown in Figure 5. The prosthetic foot of the supported leg is placed on a step. From the maximally bent position, which is shown in the left-hand illustration in Figure 6, the supported leg or the prosthetic knee joint or the knee joint axis 15 is pushed forward against resistance via the ankle joint towards the forefoot. This state, which is shown in the second illustration from the left in Figure 6, is recorded step by step via a spatial position sensor 50 on the lower part or via an angle sensor that detects the position of the lower part 20 relative to the prosthetic foot 60.In a first phase in which the body weight is transferred to the prosthetic side, flexion is to be prevented by applying an extension moment or a controlled flexion against an extension moment is to be permitted. Figure 6 shows a position at time t1 in which the knee joint was flexed from the starting position at time t0. The knee joint axis 15 and the body were pushed in a forward movement over the foot section or in the direction of the foot section. In the embodiment shown, the foot section allows a certain degree of dorsiflexion against resistance, for example via a pivot axis and a resistance device and / or elastically deformable structures. From such a position, the body can be lifted particularly effectively.The extension moment of the actuator is controlled accordingly so that such a position can be reached and assumed before an extension movement is initiated. The control principle as explained in Figure 3 is applied. If the conditions for supporting an extension movement are met, the actuator is activated or modulated and an extension moment is applied to support the extension of the knee joint and raise the body's center of gravity. Alternatively or additionally, a supporting extension moment already applied by the actuator, in combination with hip extension by the person using it, can lead to knee extension. This phase is shown in Figure 6 at times t1 and t2. With a decreasing knee angle, an extension moment can then be reduced.The change can occur continuously with the decreasing knee angle cpK or only from a limit knee angle cpKe. Since the horizontal distance between the pivot axis 15 and the body's center of gravity is reduced with the decreasing knee angle cpK, the flexion moment due to the body weight also decreases, resulting in a changed application of the supporting extension moment by the actuator 30. The reduction in the extension moment takes into account the fact of the reduction in the external flexion moment and is intended to prevent an uncontrolled snapping of the knee joint. The maximum extended position in which the upper part 10 is brought into the extension stop and in which no forward rotation of the upper part 10 about the pivot axis 15 can occur with a stationary lower part 20 is shown in Figure 6 at time t3.The upper part 10 and the lower part 20 are aligned in a straight line, whereby the alignment of the upper and lower parts in the extension position can be individually adjusted for each patient by adjusting the components accordingly. A dynamic configuration provides for a forward displacement of the knee axis; a very secure configuration provides for a backward displacement of the knee axis relative to the hip or foot, in which the longitudinal extension of the upper part 10 in the walking direction lies ahead of the extension of the longitudinal extension of the lower part 20 in the proximal direction.

[0072] The extension moment can be completely reduced with a decreasing knee angle cpK. Even before reaching a limiting knee angle, a change in the applied extension moment can occur, depending on changing angular positions, force ratios, moment ratios, or movement ratios, for example, a reduction in the pivoting speed in the extension direction or the like. With an actuator and a passive resistance device arranged parallel to each other, the resulting overall behavior is crucial. To achieve continuous transitions in movement, the active actuators and the passive resistance device can work against each other in the transition region.Particularly when using a passive prosthetic foot 60 that does not have an active drive, an extension resistance in the knee joint may be advantageous or necessary before reaching the extension stop if the prosthetic foot does not allow sufficient dorsiflexion and thus a forward shift of the body's center of gravity over the prosthetic foot. In such a situation, it may happen that the hip extension moment applied by the user, at a comparatively small knee angle cpK, causes an external extension moment to be applied to the knee joint. An additional internal extension moment added to the knee joint by the actuator 30 would cause the knee to strike the extension stop and snap into its maximum extension position.However, it is more pleasant for both the mechanical components and the user if an extension resistance is generated in such a situation, allowing the user to move smoothly into the extension position and into the extension stop. A simple solution for this is control solely via the knee angle cpK, based on the curve of which the extension support is stored in the control device via an extension moment by the actuator or a moment counteracting the extension via the knee angle. The respective support curves or curves of the extension moment or extension resistance can vary depending on the existing situation. The control with regard to the extent or size of the extension moment as well as the times for activating or deactivating the actuator can be set differently for standing up from a sitting position than for climbing stairs or other activities.It may be useful to reduce the extension moment in a knee angle range of 60° to 10°; in the last 10° to 5° of the knee angle (pK) before reaching the extension stop, a resistance moment against further extension can be applied.

[0073] Another influencing factor for the control of the extension moment TK via the actuator 30 is, for example, the ground reaction force GRF. In Figure 7, the left-hand illustration shows three different ground reaction force vectors, each with different force application points (COP) on the foot part, one in the toe area (F3), one in the midfoot area (F2) and one in the heel area (F1). When the COP is moved, the external moments about the pivot axis 15 change, as do the axis 25 and the body's center of gravity 5. The further forward the COP moves, the greater the external flexion moment about the hip joint axis and the greater the external extension moment about the pivot axis 15. If the COP moves backward towards the heel with the same orientation and amplitude of the ground reaction force GRF, the flexion moment about the hip joint axis 25 decreases and a flexion moment about the pivot axis 15 is generated.Accordingly, it is advantageous to also control the applied extension moment TK via the position of the force application point of the COP. The COP can be determined, for example, by measuring a pressure distribution on the sole of the foot part. In a design with a movable ankle joint, in which a movement in the ankle joint can be influenced by an actuator, such as a motor, an adjustable resistance device, or the like, the position of the COP can be actively influenced. For example, dorsal extension can be performed or permitted in order to shift the COP from the forefoot towards the center of the foot while maintaining the same position of the lower leg. Different orientations of the ground reaction force GRF are shown in the right-hand illustration of Figure 7. Depending on the orientation of the ground reaction force vector, the moment ratios around the pivot axis 15 and / or around the hip joint also change.If the ground reaction force vector F6 is oriented in the opposite direction in front of the pivot axis 15, this results in an externally acting extension moment about the pivot axis 15. If the ground reaction force vector F4 or F5 is located behind the pivot axis 15, this results in a flexion moment, each of a different magnitude, so that different extension moments TK by the actuator 30 are advantageous for lifting the body to overcome a step. The orientation of the ground reaction force can be influenced, for example, by the user via the applied hip moment or by force introduction via the arms, for example when holding on to or pulling up on a handrail. If the user pushes forward into the prosthesis and applies only a very low hip extension moment or pulls themselves forward with their arms (F4), a high external flexion moment about the knee axis results.The actuator can therefore apply a high extension moment, which performs work during knee extension and lifts the body without the knee joint snapping. If, on the other hand, the user applies a very high hip extension moment, particularly without using a handrail (F6), an external extension moment is present around the knee axis. The extension moment in the knee is reduced accordingly to prevent the knee joint from snapping. Thus, the orientation of the ground reaction force vector can also be used to control the extension moment TK. The extension moment can also be controlled as a function of the amplitude of the ground reaction force or one of its components, such as the vertical and horizontal components. In particular, with a high amplitude of the ground reaction force, i.e. a high load on the treated side or an increase in the load, the extension moment is increased.

[0074] Control of the extension moment TK and, in the further course, possibly a flexion moment against further extension movement or even the generation of flexion, can additionally be carried out on the basis of measurements of forces and / or moments. The measurement can be carried out using force sensors arranged on the appropriate prosthetic or orthotic component. Force sensors can be used to calculate the ground reaction force vectors and their individual components, for example, in the sagittal plane. The force application point COP on the foot, the orientation of the ground reaction force vector GRF, the lever arms around the ankle joint axis 65, the pivot axis 15, the hip axis 25 and / or the body's center of gravity 5 as well as the moments around this axis can be used for control.To determine these variables, one or more moments and / or forces can be measured, for example, an ankle moment, knee moment, and an axial load to determine the ground reaction force GRF in the sagittal plane. Reducing the extension moment TK applied by the actuator 30 is particularly useful when an external flexion moment about the pivot axis 15 in the knee joint is decreasing, is already low, or an external, extending moment is already being applied by the user. In addition, to determine the external forces and moments acting on the components, which influence their movement and can be used to control the extension moment, it is also possible to consider the inertial effects of the components via the accelerations and mass distributions.

[0075] In a passive prosthetic foot not equipped with a driving actuator, the external moment about the pivot axis 15 of the knee joint is influenced by the user, in particular by the hip extension moment, the load on the treated side, and by forces introduced via the arms or torso. Influence by the actuator 30 can be influenced in particular by the timing of the support of the extension movement, for example by initiating, permitting, or supporting an extension movement earlier or later. This is controlled in particular via the ground reaction force. For example, support of the extension movement can only be initiated when the force application point COP on the foot 60 is located far enough anterior, i.e., in the area of ​​the forefoot, or when a sufficiently large external flexion moment about the pivot axis 15 of the knee joint is detected.This is the case in the situations shown in Figures 5 and 6, each shown second from the left. Up to this point, an extension movement cannot be supported. The horizontal component of the ground reaction force or the orientation of the ground reaction force vector can be used to determine, among other things, how the user is moving forward or whether such a forward movement is being initiated. If this is the case, an extension moment TK can be applied by the actuator without the user running the risk of the knee joint snapping and being moved unbraked or even accelerated into the extension stop. The knee moment effective around the pivot axis can also be determined and used for control, for example to apply a higher extension moment TK with a correspondingly high external flexion moment.This is also possible without measuring an external moment, for example, by increasing the extension moment TK by the actuator until an extension movement actually begins and the knee angle decreases. As soon as an extension movement begins with a decrease in the knee angle cpK, the internal extension moment applied by the actuator 30 exceeds the external flexion moment.

[0076] In addition to control via threshold values, for example, the time at which an extension movement begins or when a certain knee angle is reached, the extension moment can be adjusted based on the position of the COP force application point at a specific time during a movement sequence, or it can be continuously adjusted if other, predefined criteria are met. For example, the extension moment TK can also be reduced if the force application point is located more anteriorly or if there is a particularly high external flexion moment on the knee joint, especially if this situation lasts for a longer period and it can be concluded that the user does not want to raise their body or that this is not possible due to the conditions in the orthopedic joint device.In addition or alternatively, such a situation can be recognized if the lower leg and / or the leg tendon are tilted particularly far forward or cover a particularly high pivoting range.

[0077] Figure 8 shows different body positions during a knee extension movement, such as standing up, in which an extension moment is applied depending on the inclination of the lower leg, the inclination of the lower part 20 or the inclination of the leg tendon 70. The inclination of the lower leg in particular allows conclusions to be drawn about the effective force relationships and the movement behavior. With a strong forward inclination of the lower leg, as shown in the left illustration a of Figure 8, a high external flexion moment around the knee axis can be inferred under load and a high extension moment is applied. The knee axis is located above the forefoot of the foot part. In particular, in the shown position of the lower and upper parts in space and in relation to one another, which can additionally be determined via sensors, an extension moment around the knee axis leads to an efficient lifting of the body.The middle image b of Figure 8 shows a position in which the foot is placed slightly forward and the lower leg has only a slight forward inclination. The hip and thigh angles are unchanged. The extension moment is reduced in this position compared to the left image a. Based on the lower leg angle, it can be concluded that there is a smaller external flexion moment around the knee axis and that an extension moment around the knee axis only leads to a lifting of the body to a lesser extent. The right image c of Figure 8 shows a position in which the lower leg is tilted backward. In such a position, the extension moment is, for example, completely reduced or resistance to extension is applied.In this position, it can be concluded that applying an extension moment around the knee axis causes the knee joint to snap and does not raise the body's center of gravity. In this way, the extension moment can be scaled depending on the lower leg inclination, particularly continuously. Alternatively or additionally, an extension moment supporting knee extension is only applied when a certain degree of forward inclination is exceeded or when there is no significant backward inclination of the lower leg.

[0078] The inclination of the lower leg or the inclination of the longitudinal extent of the lower part 20 allows conclusions to be drawn about the respective movement behavior and the respective movement situations. For example, an extension movement in the knee joint can be initiated depending on the forward inclination of the lower leg or the lower part 20 when a loaded prosthesis or orthosis is used. The loading of a prosthesis or orthosis is detected by corresponding sensors, either in the foot part 60 or in the lower part 20 or by transmitting a moment about the pivot axis 15. An extension movement is only supported by an extension moment TK when a sufficiently large forward inclination, i.e. a tilting of the longitudinal extent of the lower part 20 in the forward direction around a pivot point on the floor or around the ankle joint axis 65, is detected.This ensures that the foot 60 initially rolls forward and the body weight is pushed over the foot 60 before an extension movement or extension support occurs. This situation corresponds to the first two images in Figures 5 and 6. The rolling movement or forward tilt can be accompanied by knee flexion or bending around the pivot axis 15, with the knee joint resisting flexion. The further the pivot axis 15 or the body's center of gravity is located above or in front of the foot, the more efficient the lifting of the body by an extension moment TK. The extension moment can therefore also be increased or scaled with the forward tilt of the lower part 20, so that higher extension moments are applied when the lower leg is rotated further forward.At the same time, if the backward tilt is too strong, as shown in the right-hand illustration of Figure 8, the support of the extension movement by the actuator 30 can be reduced or completely eliminated. Both an absolute and a relative forward tilt, for example, measured from the initial contact when climbing stairs, or from the beginning of loading or knee extension when standing up, can be used for control.

[0079] It is also possible to have high extension resistance at the beginning of an extension movement. If a decrease in forward tilt, insufficient absolute forward tilt, and / or backward tilt is detected as the movement progresses, the extension moment can be reduced or kept at a low level, or extension can be prevented or hindered by increased extension resistance. This prevents the knee joint from snapping into extension, and the extension moment TK makes no contribution to raising the body's center of gravity.

[0080] Analogous to the control via the ground reaction force GRF, a scaling or continuous adjustment of the support can be carried out by an extension moment TK via the actuator based on the angular position of the lower part 20. In one embodiment, it is provided to control the applied extension moment or an extension movement in a closed control loop via the lower part 20, for example, to keep the lower part 20 mounted in a certain position or to achieve a desired angular profile or angular velocity profile.During a standing-up movement, as shown in different variants in Figure 5, a high extension moment is applied in the left position, a lower extension moment is applied when the lower part 20 is inclined forwards or at a lower level, and a backward inclination, i.e. when the lower part is inclined behind the vertical, an extension moment is reduced by the actuator, is not applied, or an extension resistance is introduced.

[0081] A variation of the control via the orientation of the lower part 20 is shown in Figure 9, in which, instead of standing up, overcoming an obstacle or climbing stairs is shown. While the ground reaction force is identical in all variants, the treated side is in different positions. The greatest forward inclination of the lower part 20 is shown in the middle illustration b, at which a very high extension moment can be applied. In the case of a backward inclination, as in the right illustration c of Figure 9, an extension resistance can be useful to prevent snapping or a rapid stop in the extension stop. In the position of the lower part 20 in the left illustration a of Figure 9, an average extension moment TK is applied by the actuator 30. In addition to the lower leg inclination, the ground reaction force vector and / or components thereof can also be recorded.This allows the position and orientation of the ground reaction force in relation to the lower leg, especially in relation to the knee axis, as well as the amplitude to be determined and the extension moment to be controlled depending on the forces and moments acting on the lower part.

[0082] Figure 10 shows the relationship between the lower leg inclination <pS bzw. Neigung des Unterteils 20 und der Orientierung der Beinsehne 70 oder die relative Position des Fußes im Verhältnis zu der Hüfte sowie der Knieachse, insbesondere in der Horizontalen, dargestellt. Die Neigung des Unterteils 20 bzw. des Unterschenkels beinhaltet implizit die relative Lage des Fußes 60 gegenüber dem Knie und insbesondere der Schwenkachse 15. Über die Länge des Unterschenkels, die in der Steuerungseinrichtung hinterlegt sein kann, und über den Unterschenkelwinkel kann die relative Position der Knieachse 15 zum Fußteil 60 ermittelt werden. Analog kann die relative Lage der Hüfte zum Fußteil 60 ermittelt werden, wobei zusätzlich die Länge und Orientierung des Oberschenkels berücksichtigt werden. Dies ist in der linken Darstellung a der Figur 10 gezeigt.Alternatively or additionally, the orientation of the leg tendon 70, which is shown in Figure 10 in the third illustration from the left c, or the position of the foot 60 under the body relative to the hip axis 25 can be used to control or initiate the extension movement. The distance AXH of the foot 60 from the hip axis 25 and / or the leg tendon orientation must not exceed a certain, predetermined value in a specific movement situation in order to support an extension movement. If the lower leg 20 or the leg tendon 70 is tilted too far backwards or if the distance between the foot 60 and the pivot axis 25 of the joint in the sagittal plane is too great, especially if the hip joint is located behind the foot, an extension moment can be significantly reduced or no flexion resistance can be applied at all.The extension movement or the application of an extension moment can also be scaled or continuously changed depending on the orientation of the leg tendon 70, its length or its displacement or the relative foot position to the hip joint.

[0083] Figure 11 shows a typical relationship between the position of the force application point (COP) on the foot XCOP and the external knee moment MK with the orientation of the lower leg cpS, as expected, for example, for a passive prosthetic foot when rolling over a flat surface. The orientation and amplitude of the ground reaction force, shown in the right-hand figure of Figure 11 , remain constant. The right-hand figure shows a position a in which the lower leg is rotated backward, which in this figure corresponds to a negative lower leg angle. <pS entspricht. Der COP liegt im Fersenbereich. Bei vertikaler Belastung ergibt sich ein externes kniebeugendes Moment, was in der Figur 11 als positiver Wert in der linken Darstellung dargestellt ist. Mit der Verringerung der Rückwärtsneigung des Unterschenkels und im Weiteren der Vorwärtsneigung wandert der COP nach vorne und das externe kniebeugende Moment nimmt ab.Once a certain lower leg inclination is reached, the external knee moment changes sign and an external knee extension moment is created. If the lower leg is tilted even further forward, the external knee moment initially increases and then decreases again, as the COP can no longer move forward beyond the forefoot, while the knee axis moves further forward with increasing forward inclination. Once a certain forward inclination is reached, an external knee flexion moment is created again. The right-hand illustration shows such a position b, in which the COP is in the forefoot area and the ground reaction force generates an external knee flexion moment. In an ankle joint with variable mobility around the ankle, which is controlled by an actuator, the relationship between the COP curve, the knee moment curve and the lower leg angle can be influenced, for example by allowing dorsiflexion.It is particularly effective to support a knee extension movement when an external knee flexion moment is present, while in the case of an external knee extension moment, resistance to the extension movement can prevent snapping. Based on these relationships, a knee extension movement can be controlled depending on the COP and / or lower leg angle, and possibly depending on the ankle angle, so that a knee extension movement is initiated or supported when it can be concluded that an external knee flexion moment is present, for example, when the COP is in the forefoot area and / or the lower leg is tilted forward.Alternatively or in addition, the extension moment can be reduced or resistance can be applied to an extension movement if it can be concluded that a knee flexion moment is decreasing or a knee extensor moment is increasing, for example if the COP moves from the forefoot towards the heel, particularly in combination with a reduction in the forward inclination of the lower leg. It is possible to use the ankle moment as an alternative or in addition to the COP, as this also provides information about whether the foot part is loaded at the forefoot or in the heel area. Characteristic parameters of the orthopedic device, such as the nature of the foot part, the rolling characteristics of the foot part or the geometric arrangement of the components in relation to one another, can be stored in the control system and used for this purpose.Furthermore, additional determined variables, in particular kinematic and kinetic variables and the like, can also be used for control purposes.

[0084] In the representations of Figure 12, the curves of the knee angle cpK and a lower leg angle <pS für das Aufstehen bzw. Treppenaufwärts Gehen gezeigt. Zunächst wird eine Kniebeugung gegen einen Widerstand zugelassen, sodass sich der Kniewinkel cpK erhöht, anschließend wird eine Extension bewirkt, sodass sich der Kniewinkel cpK verringert, bis eine Streckung erreicht wird. Gleichzeitig verringert sich der Unterschenkelwinkel cpS, der zwischen der Längserstreckung des Unterteils 20 und der Horizontalen in Gehrichtung gemessen wird. Es erfolgt somit zunächst eine Dorsalflexion bei einem zunehmenden Kniewinkel cpK und einem abnehmenden Unterschenkelwinkel cpS, bei einer Extension erfolgt gleichzeitig eine Plantarflexion und damit wieder eine Vergrößerung des Unterschenkelwinkels.

[0085] Figure 13 shows a variant of a movement sequence similar to Figure 12, in which the knee angle cpK is initially kept constant, for example by locking the knee joint against flexion, while a forward rolling movement takes place, represented by the increasing lower leg angle cpS, which corresponds to a forward rotation. With increasing forward rotation, the extension moment TK applied by the actuator increases around the knee axis. At the same time, plantar flexion occurs. Subsequently, after maximum dorsiflexion has been reached, extension assistance occurs during extension in the knee joint. The knee extension movement is initiated when the extension moment applied by the actuator increases more sharply, for example based on the lower leg angle, the ankle moment or other determined sensor information, than the external knee moment and exceeds it, which is the case at time t1.A mechatronic foot, for example, can allow plantar flexion to facilitate or increase the extent of knee flexion or rolling over. Knee extension or straightening only occurs when a certain forward inclination of the lower leg is reached, with the extension movement being controlled or regulated in such a way that the lower leg or lower part 20 does not snap back quickly. This is achieved, for example, by reducing the extension moment during knee extension, which is illustrated in Figure 13 between times t2 and t3 by a decrease in the extension moment TK. Before full extension is reached, resistance to an extension movement is also applied, which is illustrated as a negative moment TK.

[0086] Figure 14 shows a control of the extension moment TK as a function of the movement speed v. The movement speed can be, for example, the walking speed, the rotational speed of the upper or lower part or the leg tendon, or the horizontal or vertical translational speed of the knee axis or the torso. The movement speed can be determined using absolute and relative angular velocities as well as the segment length stored in the control system, particularly during rolling over the foot part. Alternatively or additionally, accelerations can be measured and velocities determined from this by integration, particularly in the swing phase when the foot part is not in contact with the ground. Furthermore, the impulse and movement speed can be determined from the rates of change of forces and moments, for example, via the rate of increase of the axial force or the ankle moment.Relative angular velocities, such as knee angular velocity, can also be used as a measure of movement speed. Particularly rapid knee flexion in the load response suggests that a high movement speed is present. The current movement speed can be used, but also an average movement speed or the movement speed of a previous movement phase. In a first curve in Figure 14 at a movement speed v1, represented by dashed lines, knee flexion initially occurs, represented by the increasing knee angle cpK and an increase in the knee extension moment TK.A knee extension movement is then supported, whereby the knee extension moment TK is reduced during knee extension and towards the end of the extension movement, for example in the last 10° before the extended position is reached, the extension is resisted, represented by the negative moment TK. In the second course with a higher movement speed v2, represented by solid lines, for example a higher forward speed of the torso or a higher rolling speed of the lower leg forwards, a rapid knee flexion takes place, whereby the extent of knee flexion in the example shown is as great as at a lower movement speed, which does not necessarily have to be the case. A greater extent of knee flexion can also be permitted. Based on the determined, higher movement speed v2, the knee extension moment TK is increased more than at the lower movement speed v1.After an initial knee flexion, knee extension is assisted by the actuator, with the knee extension moment TK being controlled to prevent the knee joint from snapping or a rapid backward rotation of the lower part. The increased movement speed allows for greater support for an initial knee extension movement. At a higher movement speed, the body has greater momentum. A change in momentum requires the application of forces and moments.If, during a standing-up movement or at the beginning of the standing phase when climbing stairs, the user initially builds up a forward momentum which corresponds to an increased speed of movement, this movement can be counteracted by a higher knee extension moment compared to a static movement sequence, which not only reduces the forward momentum but also creates a change in momentum upwards or effectively lifts the body.

[0087] Figure 15 shows a control of the extension moment TK as a function of at least one biosignal B, which is made available to the control system via a human-machine interface. The control is not carried out exclusively on the basis of the biosignal, but one or more other variables are used for the control, such as kinematic and kinetic variables and the like, which are determined via sensors. In particular, based on these variables, a basic characteristic is provided which is modulated by the at least one biosignal. For example, the activation of muscles or muscle groups can be recorded via electrodes, and this information, or variables derived from it, can be forwarded to the control device. A stronger activation of the muscles corresponds, for example, to a stronger biosignal B.The human-machine interface makes it possible to intentionally and / or intuitively influence the function of the orthopedic device, in particular to modulate the extension moment TK ZU applied by the actuator in at least one movement phase, for example to increase or decrease it and / or to change the time or the rate of change of an increase or decrease. In a first curve, shown as dashed lines, a low biosignal B1 is present, for example, little or no muscle tension. As in Figure 14, knee flexion initially occurs against an increasing extension moment TK, for example based on the knee angle or the ankle moment, and subsequently a knee extension movement is supported by the extension moment.During knee extension, the extension moment TK is reduced again and, before full knee extension is reached, resistance to extension is applied, particularly in a way that prevents the knee joint from snapping. In the second curve, shown as solid lines, a higher biosignal B2 is present, for example, stronger muscle tension. Based on the biosignal B2, a higher extension moment TK is applied compared to the first curve. Due to the higher extension moment in the knee flexion movement in combination with the load applied by the user, the flexion movement is stopped earlier in the example shown in Figure 15, the knee extension movement is initiated earlier, and the extension movement occurs more quickly. To prevent the knee joint from snapping or a rapid backward rotation of the lower part, the extension moment is reduced earlier during the extension movement.The resistance to a knee extension movement before the extension stop is reached is also increased in the case of the higher biosignal B2. The extent of modulation of the extension moment via the biosignal can depend on other determined variables, in particular kinematic and kinetic variables determined via sensors and the like. This can prevent, for example, an extension moment from being applied by the actuator due to strong muscle tension in an unfavorable situation, which leads to the knee joint snapping quickly. In a position a as shown in Figure 8 on the left, which can be determined, for example, via the lower leg angle and the knee angle, a greater degree of modulation can be permitted than in the right-hand illustration c of Figure 8. Furthermore, it is possible to modulate the time at which the knee extension movement is initiated via the biosignal B.For example, a user can initially generate a low biosignal B1 in order to achieve a high degree of initial knee flexion. The control system can keep the extension moment low when the biosignal B1 is low. Alternatively, if the flexion movement is blocked, a pronounced rolling movement forward can occur, whereby the knee axis and / or the body can be pushed towards and over the foot section. Increasing the biosignal to a higher level B2, for example by tensing muscles, can increase the knee extension moment, thereby initiating the extension movement. Through such control, the user is able to influence the behavior of the orthopedic device, in particular the time at which the extension movement begins and / or the degree of support.In addition to influencing the control of the knee joint, the control of a movable ankle joint, whose movement can be controlled via an actuator, can also be modulated via a human-machine interface and at least one biosignal, for example, a resistance against dorsal extension or a supporting plantar flexion moment can be increased or reduced.

[0088] Figure 16 shows the course of the extension moment TK as a function of axial load (Fz) and the position of the COP (xCOP) during a knee extension movement. Shortly after initial contact, at time t0, the body weight is transferred to the treated side, which is represented by the increase in the axial force Fz. The foot part rolls forward from the heel over the middle of the foot, causing the COP to move forward, represented by the increase in the COP position xCOP. At the same time, dorsiflexion occurs in the ankle. Knee flexion is prevented by the knee moment applied by the actuator. In a first variant, shown as a dashed line in the middle and lower illustrations, the COP moves only slightly beyond the middle of the foot. The extension moment applied by the actuator is increased depending on the position of the COP and subsequently a knee extension movement is initiated from time t1.In the control system shown, the extension moment TK is positively correlated with the COP position. In the example shown, knee extension is initiated by the user's hip extension at an approximately constant extension moment TK. Hip extension tilts the ground reaction force vector and reduces the external flexion moment around the knee axis.

[0089] In the initial phase of knee extension, the COP moves slightly backward, and the extension moment is reduced depending on the COP position. Starting at time t2, the extension moment TK is reduced as the knee angle decreases to achieve a harmonious knee extension movement. Before full knee extension is reached at time t3, resistance to knee extension is applied, preventing a harsh impact against the extension stop.

[0090] In a second variant, shown by the solid lines in the middle and bottom images of Figure 16, the COP moves down to the forefoot. This is the case, for example, if the user pushes forward particularly vigorously during the stance phase, rolls forward with particular momentum, or pulls themselves forward on a handrail. With an elastic foot section, this is accompanied by greater dorsal flexion. In an ankle joint whose ankle movement can be influenced by a control system, a greater forward movement of the COP can be achieved by increasing resistance to dorsal extension or by a greater degree of plantar flexion. The ankle joint can also be controlled so that a certain position of the COP is reached, or so that the COP position does not move too far forward or backward.The COP being positioned further forward indicates that a higher extension moment can be applied without causing an uncontrolled snapping of the knee joint or an uncontrolled backward rotation of the lower leg. Based on the COP position, the extension moment in the knee TK is increased more than in the first course. The knee extension movement is only initiated after the COP has moved from the heel towards the forefoot, or is located sufficiently far forward. The initial knee extension movement is also more strongly supported based on the COP position, with the extension moment being reduced again with the backward movement of the COP between times t1 and t2. The extension moment in the knee extension movement can also be controlled so that the COP does not move too far backward, in particular does not move as far as the heel. In Figure 16, for example, the COP only moves as far as the middle of the foot.

[0091] Alternatively or in addition to control via the COP, control via the ankle moment can also be used, which allows conclusions to be drawn about the loading conditions on the treated side and thus the extent of the extension moment, especially in combination with other determined kinematic and / or kinetic variables.

[0092] Figure 17 shows the functional relationships between an extension moment TK applied by the actuator versus a lower leg angle cpS, the position of the force application point COP, and an external knee moment MK. The resulting or actually applied extension moment TK is any non-linear function with multiple input variables, which, for example, can be completely reduced in the case of a particularly strong inclination of the lower leg in the anterior or posterior direction, in order to have a maximum in an area around the vertical. With a changing COP, the knee extension moment TK to be applied increases as the COP moves forward. Only when the COP is shifted towards the toes or into the front ball area is the extension moment TK reduced again. The applied internal extension moment TK is changed depending on the magnitude of the external knee moment MK in the flexion direction.As the flexion moment increases, the applied extension moment is increased up to a maximum value of the external flexion moment, at which the forces and moments are so great that extension support is no longer appropriate. The relationships between the extension moment TK to be applied and the parameters such as the lower leg angle cpS, force application points COP or external flexion moment MK can be superimposed on one another using fuzzy logic, for example via “AND” operations. Figure 18 shows a patient in a kneeling position with the treated side resting on the proximal end of the lower part 20. In a natural leg, this corresponds to a load on the patella with a lower leg stretched backwards.In such a position, even with an initiated extension movement and a reduction in the knee angle cpK, support from an applied extension moment TK may be undesirable. The same applies to a position shown in Figure 19, in which the angular relationship between the upper part 10 and the lower part 20 is the same as that shown in Figure 18, but with a different orientation. Based on the two positions, in particular the orientation of the upper part 10 and the lower part 20 in space or the orientation of the leg tendon 70 in space, it can be concluded that no extension is to be supported or initiated.

[0093] In addition to segment angles, relative positions, and ground reaction force components, the time derivatives of these variables can also be used for control. For example, if a rolling movement or loading is particularly dynamic, involving high speed or rapid load transfer, an extension moment (TK) can be increased or an extension movement can be performed more quickly. Due to the more dynamic movements, it can be assumed that the body has a lot of forward momentum and a faster extension movement is required. Any resistance moments required before reaching the extension limit are also adjusted accordingly.

Claims

Patent claims 1. A method for controlling an orthopaedic knee joint device having an upper part (10) and a lower part (20) which are pivotably mounted to one another about a pivot axis (15), having an actuator (30) which is coupled to the upper part (10) and the lower part (20) and influences a state of movement of the upper part (10) and / or the lower part (20), wherein the actuator (30) is coupled to a control device (40) which is coupled to at least one sensor (50) and activates, deactivates or modulates the actuator (30) on the basis of sensor values ​​of the at least one sensor (50), characterized in that an extension moment (TK) is applied by the actuator (30), which causes an extension movement with a decreasing knee angle ( <PK) bewirkt oder unterstützt und dass während der Extensionsbewegung das aufgebrachte Extensionsmoment (TK) verringert wird.

2. Method according to claim 1 , that the extension moment with decreasing knee angle ( <PK) verringert wird und / oder bei zunehmenden Kniewinkel (<PK) erhöht wird.

3. Method according to claim 1 or 2, characterized in that the extension moment (TK) is only applied after reaching a specified starting knee angle (PKS) and / or the applied extension moment (TK) is only reduced after reaching a specified knee angle limit value (cpKf).

4. Method according to one of the preceding claims, characterized in that the extension moment (TK) is applied only up to a specified limit knee angle (cpKi) before reaching an extension stop.

5. Method according to one of the preceding claims, characterized in that after a reduction of the extension moment (TK) before reaching the extension stop, a resistance counteracting the extension movement is applied.

6. Method according to one of the preceding claims, characterized in that the extension moment (TK) is changed depending on the position of the upper part (10), the position of the lower part (20) and / or the position and / or length of a leg tendon (70).

7. Method according to one of the preceding claims, characterized in that the extension moment (TK) is changed depending on the size, the point of application (COP) and / or the orientation of the ground reaction force (GRF).

8. Method according to claim 7, characterized in that the magnitude and orientation of the ground reaction force (GRF) is determined from the axial force acting on the lower part (20), a knee moment acting around the knee joint and a moment acting in the lower part.

9. Method according to one of the preceding claims, characterized in that the extension moment (TK) is changed as a function of the position of the pivot axis (15) and / or a hip joint axis (25) and / or the torso relative to a foot part (60) arranged on the lower part (10).

10. Method according to one of the preceding claims, characterized in that the extension moment (TK) is only applied when the position of the upper part (10), the lower part (20) and / or the leg tendon (70) in space is within predetermined limit values.

11. Method according to one of the preceding claims, characterized in that the actuator (30) is designed as a drive or has a drive and a resistance device which are activated, deactivated or modulated by the control device (40).

12. Method according to one of the preceding claims, characterized in that the extension moment (TK) is determined as a function of speeds and / or accelerations of the upper part (10), the lower part (20), a foot part (60) and / or the leg tendon (70) are changed.

13. Method according to one of the preceding claims, characterized in that the extension moment (TK) is positively correlated with a forward rotation and / or forward inclination of the lower part (20).

14. Method according to one of the preceding claims, characterized in that the extension moment (TK) is reduced when the lower part (20) performs a reverse rotation or falls below a predetermined angle of inclination (cps).

15. Method according to one of the preceding claims, characterized in that the extension moment (TK) is increased during a forward rotation of the lower part (20).

16. Method according to one of the preceding claims, characterized in that the extension moment (TK) is positively correlated with the position of a force application point (COP) and / or an ankle moment and / or changes thereof.

17. Method according to one of the preceding claims, characterized in that for climbing stairs and / or standing up, a free flexion of the knee joint is set or a flexion resistance is reduced and then the extension movement is supported by the actuator (30).

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