Prosthetic knee joint and control method thereof

Patent metadata

Field	Value
Publication number	US-2016367385-A1
Application number	US-201615183338-A
Country	US
Kind code	A1
Filing date	Jun 15, 2016
Priority date	Jun 19, 2015
Publication date	Dec 22, 2016
Grant date	—

Abstract

A prosthetic knee joint includes a knee portion coupled to the socket, a cylinder that is coupled to the knee portion and limits or aids operation of the knee portion, a knee angle sensor that directly or indirectly detects a knee angle value, and a control unit that controls driving of the cylinder. The control unit may calculate a knee angular velocity value based on the knee angle value detected by the knee angle sensor. The control unit determines whether the knee portion is in a knee still state based on the knee angular velocity value and automatically restricts contraction of the cylinder based on a time duration in which the knee portion is in the knee still state.

First claim

What is claimed is:

1 . A prosthetic knee joint that couples a foot portion and a socket that corresponds to a thigh of a prosthesis user, comprising:
a knee portion coupled to the socket; a cylinder coupled to the knee portion, the cylinder limiting or aiding operation of the knee portion; a knee angle sensor directly or indirectly detecting a knee angle value which is an angle of the knee portion; and a control unit coupled to the knee angle sensor, the control unit controlling driving of the cylinder, wherein the control unit calculates a knee angular velocity value based on the knee angle value detected by the knee angle sensor, and the control unit determines whether the knee portion is in a knee still state based on the knee angular velocity value and automatically restricts contraction of the cylinder based on a time duration in which the knee portion is in the knee still state.

2 . The prosthetic knee joint of claim 1 , wherein
the control unit restricts contraction of the cylinder when the knee angle value is on a knee flexion side with reference to a predetermined value.

3 . The prosthetic knee joint of claim 1 , further comprising:
a load sensor directly or indirectly detecting a load value of the prosthetic knee joint on the foot portion, wherein the control unit restricts contraction of the cylinder when the load value provided from the load sensor is larger than a predetermined value.

4 . The prosthetic knee joint of claim 3 , wherein
the control unit lifts the restriction on contraction of the cylinder when the load value exceeds an upper-limit load threshold value that is larger than the predetermined value.

5 . The prosthetic knee joint of claim 1 , wherein
the control unit automatically restricts contraction of the cylinder when the knee still state continues for a predetermined time duration T 1 .

6 . The prosthetic knee joint of claim 1 , wherein
after contraction of the cylinder is restricted, the control unit automatically lifts the restriction on contraction of the cylinder when the load value is below a predetermined value or when the knee angle value shifts to a knee extension side and the knee angle value continues to be below a predetermined threshold value for a predetermined time duration T 2 or longer.

7 . The prosthetic knee joint of claim 5 , wherein
after contraction of the cylinder is restricted, the control unit automatically lifts the restriction on contraction of the cylinder when the load value is below a predetermined value or when the knee angle shifts to a knee extension side and the knee angle value continues to be below a predetermined threshold value for a predetermined time duration T 2 or longer, and wherein relationship between the time duration T 1 and the time duration T 2 is represented as T 1 >T 2 .

8 . The prosthetic knee joint of claim 1 , wherein
after contraction of the cylinder is restricted, the control unit automatically lifts the restriction on contraction of the cylinder when a rotational moment of the prosthetic knee joint on the socket in an extension direction exceeds a predetermined moment threshold value.

9 . The prosthetic knee joint of claim 1 , wherein
the control unit automatically restricts contraction of the cylinder when the prosthetic knee joint has experienced two states: one is that the knee angle value exceeds a predetermined knee angle change upper-limit threshold value and the other is that the knee angle value falls below a predetermined knee-angle change lower-limit threshold value.

10 . A prosthetic knee joint that couples a foot portion and a socket that corresponds to a thigh of a prosthesis user, comprising:
a knee portion coupled to the socket; a cylinder coupled to the knee portion, the cylinder limiting or aiding operation of the knee portion; a knee angular velocity sensor directly or indirectly detecting a knee angular velocity value which is a change of angle of the knee portion per unit time; and a control unit coupled to the knee angle sensor, the control unit controlling driving of the cylinder, wherein the control unit determines whether the knee portion is in a knee still state based on the knee angular velocity value detected by the knee angular velocity sensor and automatically restricts contraction of the cylinder based on a time duration in which the knee portion is in the knee still state.

11 . A prosthetic knee joint that couples a foot portion and a socket that corresponds to a thigh of a prosthesis user, comprising:
a knee portion coupled to the socket; a cylinder coupled to the knee portion, the cylinder limiting or aiding operation of the knee portion; a knee angle sensor directly or indirectly detecting a knee angle value which is an angle of the knee portion; a control unit coupled to the knee angle sensor, the control unit controlling driving of the cylinder; and a load sensor directly or indirectly detecting a load value of the prosthetic knee joint on the foot portion, wherein after contraction of the cylinder is restricted, the control unit automatically lifts the restriction on contraction of the cylinder when the load value obtained from the load sensor is below a predetermined value or when the knee angle value shifts to a knee extension side and the shifting of the knee angle value continues for a predetermined time duration or longer.

12 . A method of controlling a prosthetic knee joint that couples a foot portion and a socket that corresponds to a thigh of a prosthesis user, wherein the prosthetic knee joint includes:
a knee portion coupled to the socket; a cylinder coupled to the knee portion, the cylinder limiting or aiding operation of the knee portion; and a knee angle sensor directly or indirectly detecting a knee angle value which is an angle of the knee portion, the method comprising: calculating a knee angular velocity value based on the knee angle value detected by the knee angle sensor, and determining whether the knee portion is in a knee still state based on the knee angular velocity value and automatically restricting contraction of the cylinder based on a time duration in which the knee portion is in the knee still state.

Assignees

• Nabtesco Corp

Inventors

• Hashimoto Hiroaki
• Nakaya Yoshiaki
• Saito Masakazu
• Tada Yoshihiro
• MISAO Taishiro
• Okuda Masahiko

Classifications

• A61F2/642 Primary

  Polycentric joints, without longitudinal rotation · CPC title

• A61F2/70

  electrical · CPC title

• A61F2/64 Primary

  Knee joints · CPC title

• A61F2002/7625

  for measuring angular position · CPC title

• A61F2002/7635

  for measuring force, pressure or mechanical tension · CPC title