Multi-articulated link knee joint

Abstract

A multi-articulated link knee joint includes: a knee unit in which an upper link unit rotates relative to a lower link unit by a multi-articulated link mechanism including a plurality of link units including the upper link unit and the lower link unit; a relative position detector for detecting a relative position of the upper link unit relative to the lower link unit; and an angle detector for obtaining a bending angle of the knee unit from the detected relative position.

What is claimed is: 
     
         1 . A multi-articulated link knee joint comprising:
 a knee unit in which an upper link unit is structured to rotate relative to a lower link unit by a multi-articulated link mechanism including a plurality of link units including the upper link unit and the lower link unit;   a relative position detector structured to detect a relative position, relative to a certain link unit among the plurality of link units, of another link unit; and   an angle detector structured to obtain a bending angle of the knee unit from the detected relative position.   
     
     
         2 . The multi-articulated link knee joint according to  claim 1 ,
 wherein the relative position detector detects a distance from the certain link unit to the other link unit as the relative position, and   the angle detector obtains a bending angle of the knee unit from the detected distance.   
     
     
         3 . The multi-articulated link knee joint according to  claim 2 ,
 wherein the relative position detector includes:   a magnet provided at the certain link unit; and   a magnetic sensor provided at the other link unit, the magnetic sensor structured to detect an intensity of a magnetic field generated by the magnet.   
     
     
         4 . The multi-articulated link knee joint according to  claim 3 ,
 wherein the magnet is provided at the upper link unit, and   the magnetic sensor is provided at the lower link unit.   
     
     
         5 . The multi-articulated link knee joint according to  claim 4 ,
 wherein the magnet has an arc shape extending in a rotation direction of the upper link unit, and   a center of the arc shape is eccentric with respect to a rotation axis of the upper link unit.   
     
     
         6 . The multi-articulated link knee joint according to  claim 5 , wherein the magnet includes a first magnet and a second magnet of an arc shape arranged so as to face each other. 
     
     
         7 . The multi-articulated link knee joint according to  claim 1 ,
 wherein the relative position detector detects a rotation angle of the other link unit with respect to the certain link unit as the relative position, and   the angle detector obtains a bending angle of the knee unit from the detected rotation angle.   
     
     
         8 . The multi-articulated link knee joint according to  claim 1 ,
 wherein the multi-articulated link mechanism comprises an anterior link unit and a posterior link unit rotatably supporting the upper link unit with respect to the lower link unit,   the relative position detector detects a rotation angle of each of the anterior link unit and the posterior link unit with respect to the lower link unit as the relative position, and   the angle detector obtains a bending angle of the knee unit from the detected rotation angles of the anterior link unit and the posterior link unit.   
     
     
         9 . The multi-articulated link knee joint according to  claim 1 ,
 wherein the relative position detector comprises:   a first acceleration sensor provided at the upper link unit; and   a second acceleration sensor provided at the lower link unit,   wherein the angle detector obtains a bending angle of the knee unit on the basis of detection results of the first acceleration sensor and the second acceleration sensor.