Gait motion assisting apparatus

A gait motion assisting apparatus applicable to a knee ankle foot orthosis, wherein the knee ankle foot orthosis comprises a thigh attachment to be attached to a user's thigh, a thigh frame extending substantially vertically while supporting the thigh attachment, a lower-leg attachment to be attached to the user's lower leg, and a lower-leg frame extending substantially vertically while supporting the lower-leg attachment, wherein the lower-leg frame is capable of swinging relative to the thigh frame around a brace-side pivot axis that is coaxial with a knee joint of the user, and a swinging position of the lower-leg frame around the brace-side pivot axis when the lower leg is fully extended is defined as a forward swinging end of the lower-leg frame around the brace-side pivot axis relative to the thigh frame,

• the gait motion assisting apparatus comprises:
• a casing having a first orientation that is a connectable orientation wherein an attachment surface faces the knee ankle foot orthosis, and a drive-side pivot axis is positioned coaxially with the brace-side pivot axis, when the knee ankle foot orthosis is attached to the user's left leg, and a second orientation that is a connectable orientation wherein the casing is rotated 180° around the user's trunk axis from the first orientation when the knee ankle foot orthosis is attached to the user's right leg;
• an electric motor accommodated in the casing and capable of outputting rotational power in both a first direction toward one side and a second direction toward the other side around an axis from an output shaft;
• a drive arm comprising a proximal end part and a distal end part, wherein:
• the proximal end part is operatively connected to the output shaft so as to swing in the first direction toward one side and the second direction toward the other side around the drive-side pivot axis in accordance with an output of the output shaft in the first and second directions, respectively, and
• the drive arm is configured so that when the casing is connected to the knee ankle foot orthosis, the distal end part is directly or indirectly connected to the lower-leg frame so as to press the lower-leg frame around the brace-side pivot axis in accordance with the swing around the drive-side pivot axis;
• a rotation sensor capable of detecting a swinging position of the drive arm around the drive-side pivot axis;
• a gait motion state detection sensor for detecting a gait motion state during a gait cycle;
• a notification means for notifying the user of presence of an error;
• and
• a control device having assisting force control data used when:
• calculating a direction and a size of assisting force to be imparted to the lower-leg frame wherein the assisting force control data includes left-leg assisting force control data and right-leg assisting force control data, the left-leg assisting force control data being distinct from the right-leg assisting force control data, and wherein the left-leg assisting force control data is configured to be used when the knee ankle foot orthosis is attached to the left leg and the right-leg assisting force control data is configured to be used when the knee ankle foot orthosis is attached to the right leg of the user,
• calculating a gait motion timing during a gait cycle based on a detection signal that is input from the gait motion state detection sensor at a sampling timing,
• applying the calculated gait motion timing to a manually selected one of either the left-leg assisting force control data or the right-leg assisting force control data to calculate the direction and the size of assisting force to be imparted to the lower-leg frame, and
• performing operational control for the electric motor such that assisting force having the calculated direction and size can be obtained,
• wherein the control device is configured so as to:
• recognize as a reference value a detection signal that is input from the rotation sensor when the lower leg is fully extended,
• determine one of either the left-leg assisting force control data or the right-leg assisting force control data to use based on a detection signal that is input from the rotation sensor and that is different from the reference value, and
• when the determined one of either the left-leg assisting force control data or the right-leg assisting force control data is different from the manually selected one of either the left-leg assisting force control data or the right-leg assisting force control data selected by manual operation, notify the user of an error via the notification means.