Gait assistance apparatus and operating method thereof

1. A method of operating a gait assistance apparatus, the method comprising:

sensing, using a sensor, step motion information during at least a prior gait cycle of a user;

determining, by at least one processor, a first assistance force and a second assistance force to be applied by the gait assistance apparatus to the user for assisting respective ones of a right step of a right leg of the user and a left step of a left leg of the user in a current gait cycle based on the step motion information, the current gait cycle being subsequent to the prior gait cycle;

determining, by the at least one processor, a variable ratio based on the step motion information of the user, the variable ratio being a ratio of a first variable to a second variable, the first variable indicating an amount the second assistance force for assisting the left step of the user during the prior gait cycle influences the first assistance force for assisting the right step of the user during the current gait cycle, and the second variable indicating an amount the first assistance force for assisting the right step of the user during the prior gait cycle influences the second assistance force for assisting the left step of the user during the current gait cycle;

adjusting, by the at least one processor, the first assistance force and the second assistance force based on the variable ratio to generate an adjusted first assistance force and an adjusted second assistance force for assisting respective ones of the right step and the left step of the user in the current gait cycle; and

instructing, by the at least one processor, a driver to transmit the adjusted first assistance force to the right leg of the user during the current gait cycle and the adjusted second assistance force to the left leg of the user during the current gait cycle.

2. The method of claim 1 , wherein the determining the variable ratio comprises:

determining a gait variability of the user based on the step motion information of the user; and

determining the variable ratio based on the gait variability and a reference value.

3. The method of claim 2 , wherein the determining of the gait variability comprises:

identifying the current gait cycle of the user, based on the step motion information of the user; and

determining the gait variability based on a similarity between the step motion information obtained during the current gait cycle and the step motion information obtained during the prior gait cycle.

4. The method of claim 3 , further comprising:

determining the similarity between the step motion information obtained during the current gait cycle and the step motion information obtained during the prior gait cycle by comparing (i) one or more of a step time, a joint motion range, a stride, a gait speed and a bilateral symmetry associated with the current gait cycle and (ii) one or more of the step time, the joint motion range, the stride, the gait speed and the bilateral symmetry associated with the prior gait cycle.

5. The method of claim 2 , wherein the determining the variable ratio based on the gait variability and the reference value comprises:

increasing, by the at least one processor, the variable ratio in response to the gait variability being less than the reference value such that the amount the second assistance force for assisting the left step of the user during the prior gait cycle influences the first assistance force for assisting the right step of the user during the current gait cycle increases and the amount the first assistance force for assisting the right step of the user during the prior gait cycle influences the second assistance force for assisting the left step of the user during the current gait cycle increases; and

decreasing, by the at least one processor, the variable ratio in response to the gait variability being greater than or equal to the reference value such that the amount the second assistance force for assisting the left step of the user during the prior gait cycle influences the first assistance force for assisting the right step of the user during the current gait cycle decreases and the amount the first assistance force for assisting the right step of the user during the prior gait cycle influences the second assistance force for assisting the left step of the user during the current gait cycle decreases.

6. The method of claim 1 , wherein the determining, by at least one processor, the first assistance force and the second assistance force comprises:

determining the first assistance force sufficient to swing the right leg of the user while the left leg of the user acts as a pivot, and

determining the second assistance force sufficient to swing the left leg of the user while the right leg of the user acts as the pivot.

7. A gait assistance apparatus comprising:

at least one sensor configured to sense step motion information during at least a prior gait cycle of a user; and

a processor configured to:

determine a first assistance force and a second assistance force to be applied by the gait assistance apparatus to the user for assisting respective ones of a right step of a right leg of the user and a left step of a left leg of the user in a current gait cycle based on the step motion information, the current gait cycle being subsequent to the prior gait cycle,

determine a variable ratio based on the step motion information of the user, the variable ratio being a ratio of a first variable to a second variable, the first variable indicating an amount the second assistance force for assisting the left step of the user during the prior gait cycle influences the first assistance force for assisting the right step of the user during the current gait cycle, and the second variable indicating an amount the first assistance force for assisting the right step of the user during the prior gait cycle influences the second assistance force for assisting the left step of the user during the current gait cycle

adjust the first assistance force and the second assistance force based on the variable ratio to generate an adjusted first assistance force and an adjusted second assistance force for assisting respective ones of the right step and the left step of the user in the current gait cycle, and

instructing a driver to transmit the adjusted first assistance force to the right leg of the user during the current gait cycle and the adjusted second assistance force to the left leg of the user during the current gait cycle.

8. The gait assistance apparatus of claim 7 , wherein the processor is configured to:

determine a gait variability of the user based on the step motion information of the user, and

determine the variable ratio based on the gait variability and a reference value.

9. The gait assistance apparatus of claim 8 , wherein the processor is configured to:

identify the current gait cycle of the user, based on the step motion information of the user, and

determine the gait variability based on a similarity between the step motion information obtained during the current gait cycle and the step motion information obtained during the prior gait cycle.

10. The gait assistance apparatus of claim 9 , wherein the processor is configured to,

determine the similarity between the step motion information obtained during the current gait cycle and the step motion information obtained during the prior gait cycle by comparing (i) one or more of a step time, a joint motion range, a stride, a gait speed and a bilateral symmetry associated with the current gait cycle and (ii) one or more of the step time, the joint motion range, the stride, the gait speed and the bilateral symmetry associated with the prior gait cycle.

11. The gait assistance apparatus of claim 8 , wherein the processor is configured to determine the variable ratio by,

increasing the variable ratio in response to the gait variability being less than the reference value such that the amount the second assistance force for assisting the left step of the user during the prior gait cycle influences the first assistance force for assisting the right step of the user during the current gait cycle increases and the amount the first assistance force for assisting the right step of the user during the prior gait cycle influences the second assistance force for assisting the left step of the user during the current gait cycle increases, and

decreasing the variable ratio in response to the gait variability being greater than or equal to the reference value such that the amount the second assistance force for assisting the left step of the user during the prior gait cycle influences the first assistance force for assisting the right step of the user during the current gait cycle decreases and the amount the first assistance force for assisting the right step of the user during the prior gait cycle influences the second assistance force for assisting the left step of the user during the current gait cycle decreases.

12. The gait assistance apparatus of claim 7 , wherein the processor is configured to:

determine the first assistance force sufficient to swing the right leg of the user while the left leg of the user acts as a pivot, and

determine the second assistance force sufficient to swing the left leg of the user while the right leg of the user acts as the pivot.