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US 6,755,870 B1Granted
Leg prosthesis with an artificial knee joint and method for controlling a leg prosthesis
AssigneeBiedermann Motech GmbH
InventorsLutz Biedermann, Wilfried Matthis, Christian Schulz
Life of this patent
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Abstract
There is provided a leg prosthesis, comprising a thigh portion (1) and a lower leg portion (2) both being connected by a knee joint (3), said knee joint (3) comprising a damping element (6) for controlling the knee joint movement, and means (S1) for detecting the knee angle and means (S4-S7; S8, S8′, S9, S9′) for detecting the force acting on the prosthesis; and a control unit for controlling said damping element (6) as a function of the detected values of said knee angle and said force; and an adjustment device (10) adjusting the control of said damping element according to the type of gait and as a function of detected values of said knee angle and said force.
Claims19
A leg prosthesis comprising:
- a thigh portion;
- a lower leg portion;
- a knee joint connecting the thigh portion and the lower leg portion so that a knee angle is formed between the thigh portion and the lower leg portion;
- said knee joint comprising a damping element for controlling the knee joint movement, angle detection means for detecting the knee angle and force detection means for detecting a force acting on the prosthesis;
- a control unit for controlling said damping element as a function of the detected values of said knee angle and said force;
- and
- an adjusting device;
- wherein the control unit is structured and arranged to control said damping element as a function of control parameters (P) previously stored for different gait velocities;
- and
- the adjustment device is structured and arranged to select a control parameter (P) from said previously stored control parameters as a function of the type of gait and the detected values of said knee angle and said force, to change the selected control parameter (P) to a value (P′) equal to or different from the previously stored value as a function of the type of gait and the detected values of said knee angle and said force, to store the changed control parameter (P′) instead of the selected control parameter (P), and to use the changed control parameter (P′) as a starting point in a subsequent step.
7 more elements
A leg prosthesis comprising:
- a thigh portion;
- a lower leg portion;
- a knee joint connecting the thigh portion and the lower leg portion so that a knee angle is formed between the thigh portion and the lower leg portion;
- said knee joint comprising a damping element for controlling the knee joint movement, angle detection means for detecting the knee angle and force detection means for detecting a force acting on the prosthesis;
- a control unit for controlling said damping element as a function of the detected values of said knee angle and force;
- and
- an adjusting device;
- wherein the control unit is structured and arranged to control said damping element as a function of control parameters (P) previously determined for different gait velocities;
- the adjustment device is structured and arranged to readjust said control parameters as a function of the type of gait and the detected values of said knee angle and said force;
- said adjustment device is structured and arranged to readjust the parameters under the condition that actual step values that are determined from said detected values differ from set step values predetermined in advance that are set identically for each person wearing the prosthesis;
- said predetermined set step values comprise a maximum knee angle and a stretch lead time which is the time between an extension stop and the placing of the heel during a step;
- and
- the maximum knee angle is between 55° and 60°.
10 more elements
A leg prosthesis comprising:
- a thigh portion;
- a lower leg portion;
- a knee joint connecting the thigh portion and the lower leg portion so that a knee angle is formed between the thigh portion and the lower leg portion;
- said knee joint comprising a damping element for controlling the knee joint movement, angle detection means for detecting the knee angle and force detection means for detecting a force acting on the prosthesis;
- a control unit for controlling said damping element as a function of the detected values of said knee angle and said force;
- and
- an adjusting device;
- wherein the control unit is structured and arranged to control said damping element as a function of control parameters (P) previously determined for different gait velocities;
- the adjustment device is structured and arranged to readjust said control parameters as a function of the type of gait and the detected values of said knee angle and said force;
- said adjustment device is structured and arranged to readjust the parameters under the condition that actual step values that are determined from said detected values differ from set step values predetermined in advance that are set identically for each person wearing the prosthesis;
- said predetermined set step values comprise a maximum knee angle and a stretch lead time which is the time between an extension stop and the placing of the heel during a step;
- and
- the stretch lead time is between 0.06 and 0.1 seconds.
10 more elements
A leg prosthesis comprising:
- a thigh portion;
- a lower leg portion;
- a knee joint connecting the thigh portion and the lower leg portion so that a knee angle is formed between the thigh portion and the lower leg portion;
- said knee joint comprising a damping element for controlling the knee joint movement, angle detection means for detecting the knee angle and force detection means for detecting a force acting on the prosthesis;
- a control unit for controlling said damping element as a function of the detected values of said knee angle and said force;
- and
- an adjusting device;
- wherein the control unit is structured and arranged to control said damping element as a function of control parameters (P) previously determined for different gait velocities;
- the adjustment device is structured and arranged to readjust said control parameters as a function of the type of gait and the detected values of said knee angle and said force;
- and
- the control parameters (P) includes an extension damping gain factor (Ed) and a flexion damping gain factor (Fd), and wherein the damping element is adjusted to a predetermined damping value for the cases of extension or flexion as a function thereof, respectively.
8 more elements
A leg prosthesis comprising:
- a thigh portion;
- a lower leg portion;
- a knee joint connecting the thigh portion and the lower leg portion so that a knee angle is formed between the thigh portion and the lower leg portion;
- said knee joint comprising a damping element for controlling the knee joint movement, angle detection means for detecting the knee angle and force detection means for detecting a force acting on the prosthesis;
- a control unit for controlling said damping element as a function of the detected values of said knee angle and said force;
- and
- an adjusting device;
- wherein the control unit is structured and arranged to control said damping element as a function of control parameters (P) previously determined for different gait velocities;
- the adjustment device is structured and arranged to readjust said control parameters as a function of the type of gait and the detected values of said knee angle and said force;
- and
- said force detection means comprises total force detection means for detecting the total force acting on the prosthesis and lateral force detection means for detecting the lateral force on the prosthesis.
8 more elements
A method for controlling a leg prosthesis comprising a thigh portion;
- a lower leg portion;
- a knee joint connecting the thigh portion and the lower leg portion so that a knee angle is formed between the thigh portion and the lower leg portion, said knee joint comprising a damping element for controlling the knee joint movement, angle detection means for detecting the knee angle and force detection means for detecting a force acting on the prosthesis;
- a control unit for controlling said damping element as a function of the detected values of said knee angle and said force;
- and an adjustment device;
- wherein the control unit is structured and arranged to control said damping element as a function of control parameters (P) previously stored for different gait velocities and the adjustment device is structured and arranged to readjust the parameters as a function of the type of gait;
- said method comprising:
- repeatedly detecting values of said knee angle and said force,
- selecting a control parameter (P) from said previously stored control parameters as a function of the type of gait and the detected values of said knee angle and said force,
- controlling said damping element as a function of the selected control parameter (P),
- changing the selected control parameter (P) to a value (P′) equal to or different from the previously determined value as a function of the type of gait and the detected values of said knee angle and said force;
- and
- storing the changed control parameter (P′) instead of the selected control parameter (P).
9 more elements
A method for controlling a leg prosthesis comprising a thigh portion;
- a lower leg portion;
- a knee joint connecting the thigh portion and the lower leg portion so that a knee angle is formed between the thigh portion and the lower leg portion, said knee joint comprising a damping element for controlling the knee joint movement, angle detection means for detecting the knee angle and force detection means for detecting a force acting on the prosthesis;
- a control unit for controlling said damping element as a function of the detected values of said knee angle and said force;
- and an adjustment device;
- wherein the control unit is structured and arranged to control said damping element as a function of control parameters (P) previously determined for different gait velocities and the adjustment device is structured and arranged to readjust the parameters as a function of the type of gait;
- said method comprising detecting values of said knee angle and said force and controlling said damping element as a function of the detected values of said knee angle and said force;
- said method further comprising during each step with the prosthesis:
- determining an expected step velocity;
- determining actual step values characterizing the instantaneous type of gait from said detected values;
- comparing the actual step values with set step values predetermined in advance;
- and
- changing the control parameters as a function of the result of comparing said actual step values with said predetermined set step values;
- wherein said predetermined set step values comprise a maximum knee angle and a stretch lead time, which is the time between an extension stop and the placing of the heel during a step, and wherein the ranges for the set step values are the same for every person wearing the prosthesis;
- and
- wherein the maximum knee angle is between 55° and 60° and the stretch lead time is between 0.06 and 0.1 seconds.
12 more elements
Dependencies are inferred from the claim text.