Patent ID: 8303524
Filing Date: 2012-11-06
Classification: A61H,B25J

Abstract:
1. A control device for a walking assist device, the walking assist device having: a lifting force transmitting portion adapted to be put in contact with a trunk of a user so as to allow an upward lifting force to act on the trunk of the user; a pair of left and right foot attachment portions adapted to be fitted to feet of legs of the user; a pair of left and right leg links which connect the foot attachment portions to the lifting force transmitting portion, respectively, each of the leg links including a thigh frame extending from the lifting force transmitting portion via a first joint, a crus frame extending from each foot attachment portion via a second joint, and a third joint interconnecting the thigh frame and the crus frame so as to freely bend and stretch the thigh and crus frames; and actuators, each of which drives the third joint of the corresponding leg link, wherein the control device has a treading force measuring means which measures treading forces of the legs of the user based on outputs of treading force measurement force sensors mounted on the foot attachment portions of the walking assist device, respectively, such that each of the treading force measurement force sensors is opposed to a base of the foot of the corresponding leg of the user, and the control device controls driving forces of the actuators of the walking assist device so that a proportion between supporting forces respectively acting on the leg links of the walking assist device from the floor side coincides with a predetermined ratio determined according to the measured values of the treading forces of the legs obtained by the treading force measuring means while applying a preset desired lifting force to the trunk of the user from the lifting force transmitting portion of the walking assist device; and wherein the control device comprises: a treading force total sum decision means which decides whether or not a total sum of the measured values of the treading forces of the legs obtained by the treading force measuring means is greater than a predetermined value; and a predetermined ratio determining means which determines the predetermined ratio, according to observed values of reference parameters which have been observed based on outputs of sensors mounted on the leg links of the walking assist device other than the treading force measurement force sensors or desired values of the reference parameters which have been used for control processing of the driving forces of the actuators of the walking assist device immediately before a negative determination result of the treading force total sum decision means, by using the supporting forces acting on each of the leg links of the walking assist device from the floor side, driving torques of the third joints of each of the leg links of the walking assist device, or physical quantities having correlation with the supporting forces or the driving torques as reference parameters for determining the predetermined ratio, instead of determining the predetermined ratio according to the measured values of the treading forces of the legs of the user, in the case where the determination result of the treading force total sum decision means is negative.