Wearable robot and method for controlling the same

1. A wearable robot comprising:

an assistance device having an exoskeleton structure configured to be worn on legs of a user;

sensors including,

a pair of first electromyogram (EMG) sensors and a pair of second EMG sensors, the pair of first EMG sensors configured to attach at a first location on respective legs of the user and to detect first EMG signals, the pair of second EMG sensors configured to attach at a second location on the respective legs and to detect second EMG signals, and

an acceleration sensor configured to detect walking acceleration of the user; and

a controller configured to,

detect a start of a walking cycle in response to a rapid increase in the walking acceleration of the user,

detect a first point when, after the rapid increase in the walking acceleration of the user, one of the first EMG signals associated with a first one of the legs is in an offset state and one of the second EMG signals associated with the first one of the legs is in an onset state, the onset state being a state when a muscle corresponding to one of the sensors on the legs of the user is activated and the offset state being a state when the muscle on the legs of the user is deactivated,

set the first point as a walking assist starting point for the first one of the legs, the walking assist starting point being a point in the walking cycle in which the assistance device begins assisting the user with walking using the first one of the legs, and

apply torque to a driver for a walking assistance duration of the first one of the legs by,

instructing the driver to apply torque associated with the assistance device beginning at the walking assistance starting point,

detecting a second point when one of the first EMG signals associated with a second one of the legs is in the onset state, the onset state being a state when the muscle on the second one of the legs of the user is activated, and

instructing the driver to assist muscular power of the user for the walking assistance duration from the walking assist starting point until the second one of the legs of the user contact a ground.

2. The wearable robot according to claim 1 , wherein

the pair of first EMG sensors are configured to attach at the first location on the respective legs of the user corresponding to a location of a tibialis anterior muscle of the user, and

the pair of second EMG sensors are configured to attach at the second location on the respective legs of the user corresponding to a location of a triceps surae muscle of the user.

3. The wearable robot according to claim 1 , wherein the pair of second EMG sensors are configured to attach at the second location on the respective legs of the user corresponding to a location of a soleus muscle of the user.

4. The wearable robot according to claim 1 , wherein the controller is configured to determine if an amplitude of each of the first and second EMG signals are above or below a boundary before determining the walking assist starting point.

5. The wearable robot according to claim 1 , wherein the controller includes,

a first filter configured to filter each of the first and second EMG signals before determining the walking assist starting point; and

a second filter configured to filter each of the first and second EMG signals before determining the walking assist starting point, the second filter having a cutoff frequency different from a cutoff frequency associated with the first filter.

6. The wearable robot according to claim 5 , wherein

the first filter is a low pass filter (LPF), and

the second filter has a cutoff frequency associated therewith that is lower than the cutoff frequency associated with the first filter.

7. The wearable robot according to claim 1 , wherein the sensors further comprise: a gyro sensor configured to detect inclination of an upper body of the user.

8. The wearable robot according to claim 1 , wherein the controller is configured to calculate the torque such that the torque is proportional to inclination of a body of the user or walking speed of the user.

9. The wearable robot according to claim 1 , wherein the driver is a first driver associated with a first hip joint, and the wearable robot further comprises: a second driver associated with a second hip joint.

10. The wearable robot according to claim 9 , wherein the controller is configured to,

apply the torque to the first driver associated with the first one of the legs in a direction opposite to a walking direction of the user, and

apply the torque to the second driver associated with the second one of the legs in the walking direction of the user.

11. A method for controlling a wearable robot, the wearable robot including an assistance device having an exoskeleton structure configured to be worn on legs of a user, the method comprising:

receiving first electromyogram (EMG) signals and second EMG signals from a pair of first EMG sensors and a pair of second EMG sensors, respectively, the pair of first EMG sensors configured to attach at a first location of respective legs of the user, the pair of second EMG sensors configured to attach at a second location of the respective legs;

receiving, from an acceleration sensor, acceleration information indicating a walking acceleration of the user;

detecting a start of a walking cycle in response to a rapid increase in the walking acceleration of the user;

detecting, a first point when, after the rapid increase in the walking acceleration of the user, one of the first EMG signals associated with a first one of the legs is in an offset state and one of the second EMG signals associated with the first one of the legs is in an onset state, the onset state being a state when a muscle on the legs of the user is activated and the offset state being a state when the muscle on the legs of the user is deactivated;

setting the first point as a walking assist starting point, the walking assist starting point being a point in the walking cycle in which the assistance device begins assisting the user with walking using the first one of the legs; and

applying torque to a driver for a walking assistance duration of the first one of the legs by,

instructing the driver to apply torque associated with the assistance device beginning at the walking assistance starting point,

detecting a second point when one of the first EMG signals associated with a second one of the legs is in the onset state, the onset state being a state when the muscle on the second one of the legs of the user is activated, and

instructing the driver to assist muscular power of the user for the walking assist duration from the walking assist starting point until the second one of the legs of the user contact a ground.

12. The method according to claim 11 , wherein

the first pair of EMG sensors are configured to attach at the first location on the respective legs of the user corresponding to a location of a tibialis anterior muscle of the user, and

the second pair of EMG sensors are configured to attach at the second location on the respective legs of the user corresponding to a location of a soleus muscle of the user.

13. The method according to claim 11 , wherein the driver is a first driver associated with a first hip joint, and the wearable robot further comprises: a second driver associated with a second hip joint.

14. The method according to claim 13 , wherein the applying the torque comprises:

applying the torque to the first driver associated with the first one of the legs in a direction opposite to a walking direction of the user; and

applying the torque to the second driver associated with the second one of the legs in the walking direction of the user.