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CA-2983646-C - METHOD FOR CONTROLLING A CHANGE OF DAMPING IN AN ARTIFICIAL JOINT

CA2983646CCA 2983646 CCA2983646 CCA 2983646CCA-2983646-C

Abstract

A method for controlling a change of resistance in an artificial joint of an orthosis, an exoskeleton or prosthesis of a lower extremity. The artificial joint has an upper part and a lower part which are secured on each other so as to be pivotable about a pivot axis, a damper unit is secured between the upper part and the lower part in order to provide a resistance to flexion or extension of the artificial joint, and the damper unit is assigned an adjusting mechanism via which the resistance is changed when a sensor signal of a control unit assigned to the adjusting mechanism activates the adjusting mechanism. The resistance is changed as a function of the position and/or length of the measured or calculated leg tendon and/or the time derivatives thereof.

Inventors

  • Dirk Seifert

Assignees

  • OTTO BOCK HEALTHCARE PRODUCTS GMBH

Dates

Publication Date
20260505
Application Date
20160415
Priority Date
20150424

Claims (10)

  1. 16 Claims: 1. A method for controlling a change in resistance in an artificial joint of an orthosis, of an exoskeleton or prosthesis of a lower extremity, wherein the artificial joint has an upper part and a lower part which are fastened to one another pivotably about a pivot axis, wherein a resistance unit is fastened between the upper part and the lower part in order to provide a resistance to flexion or extension of the artificial joint, and the resistance unit is assigned an adjustment device by means of which the resistance is changed if a sensor signal of a control unit assigned to the adjustment device activates the adjustment device, wherein the resistance is changed in a manner dependent on the position and/or length of the measured or calculated leg chord and/or the derivatives thereof with respect to time, and wherein the connecting line between a hip center of rotation and a foot point is used as leg chord.
  2. 2. The method as claimed in claim 1, wherein the position of the leg chord is estimated as a sum of a lower leg angle and a fraction of a knee angle, or is calculated using the lower leg angle, the knee angle and the thigh segment length and the lower leg segment length.
  3. 3. The method as claimed in claim 1 or 2, wherein the lower leg angle or thigh angle is directly measured by means of an inertial angle sensor, or is determined by means of an position sensor on a thigh or lower leg and a knee angle sensor.
  4. 4. The method as claimed in any one of claims 1-3, wherein the length of the leg chord is determined from the knee angle and the segment lengths of thigh and lower leg.
  5. 5. The method as claimed in any one of claims 1-4, wherein the resistance is changed in a manner dependent on the direction of the change in the position and/or length of the leg chord. Date Rec;ue/Date Received 2024-02-06 17
  6. 6. The method as claimed in any one of claims 1-5, wherein a quotient is determined from the change in the position of the leg chord and the change in the thigh angle or lower leg angle and is used for the assessment of the walking situation.
  7. 7. The method as claimed in any one of claims 1-5, wherein a quotient is determined from the change in the leg chord speed and the change in the thigh speed or a lower leg speed and is used for the assessment of the walking situation.
  8. 8. The method as claimed in any one of claims 1-7, wherein a force sensor for detecting forces in the lower part is used for the detection of a stance phase or of standing.
  9. 9. The method as claimed in any one of claims 1-8, wherein the resistance is changed additionally in a manner dependent on the position or change in position of the upper part and/or of the lower part.
  10. 10. The method as claimed in any one of claims 1-9, wherein the resistance is changed if the position and/or the change in position of the leg chord overshoots or undershoots a predetermined threshold value. Date Rec;ue/Date Received 2024-02-06

Description

1 Method for controlling a change of damping in an artificial joint The invention relates to a method for controlling a change in resistance in an artificial joint of an orthosis, of an exoskeleton or prosthesis of a lower extremity, 5 wherein the artificial joint has an upper part and a lower part which are fastened to one another pivotably about a pivot axis, wherein a resistance unit is fastened between the upper part and the lower part in order to provide a resistance to flexion or extension of the artificial joint, and the resistance unit is assigned an adjustment device by means of which the resistance is changed if a sensor sig- 10 nal of a control unit assigned to the adjustment device activates the adjustment device. The method is used in particular for the control of the movement or damping behavior of artificial knee joints, but is not restricted to this, and may also be used for hip or ankle joints. 15 Artificial joints for orthoses, exoskeletons or prostheses have an upper part with an upper connection part and a lower part with a lower connection part, which are articulatedly connected to one another. In general, in the case of artificial knee joints, receptacles for a thigh stump or a thigh rail are arranged on the upper connection part, whereas a lower leg tube or a lower leg rail with a prosthetic 20 foot or a foot part are arranged on the lower connection part. In the case of a lower leg still being present, the upper part of a prosthesis is arranged on a lower leg socket, the prosthetic foot is fastened to the lower part, and in the case of orthoses, the respective components are fastened to the associated limbs. In the simplest case, the upper part and the lower part are connected pivotably 25 to one another by means of a uniaxial joint. To be able to satisfy or support different requirements during the different phases of a step or during other movements or actions in a way that is as natural as possible, a resistance device is often provided which provides flexion re- 30 sistance and extension resistance. The flexion resistance is used for setting how easily the lower part can be pivoted in relation to the upper part when a force is applied. In the case of a knee joint, the extension resistance brakes the forward Date Rec;ue/Date Received 2024-02-06 movement of the lower part and forms, inter alia, an extension limit stop, and the flexion resistance prevents undesired flexion and limits the maximum flexion in the swing phase. 5 DE 10 2008 008 284 A 1 has disclosed an orthopedic knee joint with an upper part and with a lower part arranged pivotably thereon, which lower part is assigned multiple sensors, for example a flexion angle sensor, an acceleration sensor, an inclination sensor and/or a force sensor. The position of the extension stop is determined in a manner dependent on the sensor data. DE 10 2006 021 802 A 1 describes control of a passive prosthetic knee joint with adjustable damping in a flexion direction for adaptation of a prosthesis device with top-side connection means and with a connecting element to an artificial foot. The adaptation is made to climbing stairs, wherein a low-moment lifting of 15 the prosthetic foot is detected, and the flexion damping is, in a lifting phase, lowered to below a level suitable for walking on a level surface. The flexion damping may be increased in a manner dependent on the change in the knee angle and in a manner dependent on the axial force acting on the lower leg. 20 DE 10 2009 052 887 A1 describes, inter alia, a method for controlling an orthotic or prosthetic joint with a resistance device and with sensors, wherein items of state information are provided by means of sensors during the use of the joint. The sensors detect moments or forces, wherein the sensor data of at least two of the determined variables are linked to one another by means of a mathemat- 25 ical operation, and in this way an auxiliary variable is calculated which is used as a basis for the control of the flexion and/or extension resistance. According to the prior art, for the control of the change in the damping behavior, the sensor data are evaluated quantitatively, that is to say, in general, certain 30 threshold values are predefined, in the case of the attainment or non-attainment of which the actuator is activated or deactivated, such that the resistance device provides an increased or reduced flexion or extension resistance. Date Rec;ue/Date Received 2024-02-06 Patients may use prostheses, exoskeletons or orthoses in various environments. They may walk down stairs, walk down ramps or walk on a level surface at various speeds. Furthermore, loads may be carried, which likewise has an effect on the behavior of the prosthesis or orthosis. In particular after the end of the swing 5 phase, that is to say after the setting-down of the aided leg, when the body weight is shifted onto the aided leg, there is often a requirement for increased safety for the patient. Exces