| CPC A61H 1/0274 (2013.01) [A61H 1/0244 (2013.01); A61H 2201/1215 (2013.01); A61H 2201/1463 (2013.01); A61H 2201/164 (2013.01); A61H 2201/165 (2013.01); A61H 2201/1671 (2013.01); A61H 2201/5069 (2013.01); A61H 2201/5084 (2013.01); A61H 2230/625 (2013.01)] | 6 Claims |
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1. An assist device comprising:
a first body-worn unit that is worn on an upper body of a user;
right and left second body-worn units that are worn on right and left legs of the user;
an actuator configured to provide the user with an assist force through the first body-worn unit and the second body-worn units;
a detection part configured to detect a tilt angle of the upper body of the user; and
a controller configured to obtain an assist parameter for causing the actuator to generate a desired assist force, and perform control for causing the actuator to operate at an output corresponding to the assist parameter, wherein:
when the user performs a forward leaning action that is a forward leaning action in which the user leans his or her upper body forward, the controller obtains the assist parameter for providing the user with the assist force in a direction of bringing the user to an upright standing posture based on the tilt angle and a time-based change in the tilt angle; and
the controller is configured to further perform an assistance moderation process to reduce the assist force when the time-based change in the tilt angle increases,
the controller is configured to obtain the assist parameter for providing the user with the assist force in the direction of bringing the user to an upright standing posture by
obtaining an intensity level of assist operation from the user,
acquiring the tilt angle and calculate the time-based change in the tilt angle,
obtaining a first value by multiplying the tilt angle by a virtual spring constant,
obtaining a second value by multiplying the time-based change in the tilt angle by a damper constant, the virtual spring constant and the damper constant being predetermined and based on the intensity level of assist operation, and
obtaining the assist parameter based on the first value and the second value,
a sign of the damper constant is positive when the intensity level of assist operation is greater than or equal to the predetermined intensity level, and an absolute value of the damper constant increases as the intensity level of assist operation increases, and
the direction of bringing the user to the upright standing posture is defined as negative such that the assist force is increased when the tilt angle increases and the assist force is reduced when the time-based change in the tilt angle increases.
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