Patent ID: 9289345
Filing Date: 2016-03-22
CPC Classification: A61H,G05B

Claim Text:
1. A walking assist device, comprising: a first attachment adapted to be installed to an upper body of a human being; a pair of second attachments adapted to be installed, one to a right leg and the other to a left leg of the human being; a pair of actuators; a pair of joint angle sensors configured to output signals based on the right and left hip joint angles, respectively, of the human being; and a controller configured to control an operation of each of the pair of actuators on the basis of at least output signals of the pair of joint angle sensors, wherein each of the pair of the second attachments is moved with respect to the first attachment by operating each of the pair of actuators thereby to assist relative periodic motions of the right and left legs with respect to the upper body, and the controller comprises: a first phase oscillator output element configured to measure a phase of a period motion of each thigh relative to the upper body of the human being as each of right and left components of a first phase oscillator on the basis of an output of each of the pair of joint angle sensors; a second phase oscillator output element configured to calculate, as a second phase oscillator, a phase having right and left components that change at velocities based on a difference relative to the right and left components of the first phase oscillator and right and left components of an intrinsic angular velocity; an intrinsic angular velocity setting element configured to set the right and left components of a current intrinsic angular velocity by correcting the right and left components of a previous intrinsic angular velocity by an amount based on a previous difference between each of the right and left components of the first phase oscillator and each of the right and left components of the second phase oscillator such that the previous difference approaches a desired difference; and a control signal generating element configured to generate a control signal that changes the phase of the periodic operation of each of the pair of actuators according to a change in each of the right and left components of the second phase oscillator, wherein the control signal generating element is configured to generate a control signal that defines an operational amplitude of each of the pair of actuators on the basis of a ratio of a desired stride length to a length of a leg of the human being according to an increasing function that uses the ratio as a variable thereof.