Control method and control apparatus for turning walking

1. A control method, comprising:

instructing a driver to output, in different ones of a plurality of walking phases, a rotational torque to a support attached to a user to assist the user with straight walking, the plurality of walking phases including at least a swing phase, a stance phase, and a push-off-phase;

receiving sensor information while assisting the user with the straight walking;

recognizing, based on the sensor information, that the user is performing a turning operation in a turning direction while assisting the user with the straight walking through the plurality of walking phases; and

in response to the user performing the turning operation,

adjusting at least one control parameter to assist the turning operation by gradually reducing a gain of the rotational torque associated with at least one of the swing phase, the stance phase, and the push-off-phase from the gain of the rotational torque when walking straight to a value greater than zero to generate a reduced rotational torque that varies during the at least one of the swing phase, the stance phase, and the push-off-phase, and

instructing the driver to change from outputting the rotational torque to outputting the reduced rotational torque to the support in the at least one of the swing phase, the stance phase, and the push-off-phase to assist the user in performing the turning operation such that, while performing the turning operation, the rotational torque output by the driver varies during the at least one of the swing phase, the stance phase, and the push-off-phase and is reduced as compared to the straight walking.

2. The control method of claim 1 , wherein the recognizing comprises:

tracking a variable component based on the sensor information, the variable component varying in response to the walking; and

determining whether the user is performing the turning operation based on the variable component.

3. The control method of claim 2 , wherein the determining whether the user is performing the turning operation comprises:

extracting a representative component from the variable component;

determining whether a variance in the representative component is maintained within a set range; and

determining that the user is performing the turning operation, if the variance exceeds the set range.

4. The control method of claim 3 , wherein the variable component includes one or more of a direction that a body of the user faces during the walking and a direction that a pelvis of the user faces during the walking.

5. The control method of claim 2 , wherein the variable component includes a first variable component and a second variable component, the first variable component corresponding to a motion of a left hip joint of the user, and the second variable component corresponding to a motion of a right hip joint of the user, and wherein the determining whether the user is performing the turning operation comprises:

determining whether a variance in the first variable component and a variance in the second variable component are symmetric; and

determining that the user is performing the turning operation, if the variance in the first variable component and the variance in the second variable component are asymmetric.

6. The control method of claim 1 , wherein the adjusting the at least one control parameter comprises:

determining the gain of the rotational torque to assist the turning operation; and

applying the gain to the rotational torque to generate the reduced rotational torque.

7. The control method of claim 1 , wherein the at least one control parameter includes one or more of a hip joint torque for each walking phase, an ankle joint torque for each walking phase, a knee joint torque for each walking phase, and a foot sole torque for each walking phase.

8. The control method of claim 1 , further comprising:

recognizing the turning direction associated with the turning operation based on the sensor information, wherein

the adjusting the at least one control parameter comprises adjusting the at least one control parameter based on the turning direction.

9. The control method of claim 8 , wherein the recognizing the turning direction comprises:

recognizing the turning direction based on a z-axial rotation angle of a body part from which the sensor information is obtained.

10. The control method of claim 8 , wherein, when the recognizing the turning direction recognizes the turning direction as a left turn direction, the adjusting of the at least one control parameter based on the turning direction comprises:

reducing a swing phase torque of a left hip joint of the user; and

reducing a stance phase torque of a right hip joint of the user.

11. The control method of claim 8 , wherein, when the recognizing the turning direction recognizes the turning direction as a right turn direction, the adjusting of the at least one control parameter based on the turning direction comprises:

reducing a stance phase torque of a left hip joint of the user; and

reducing a swing phase torque of a right hip joint of the user.

12. The control method of claim 8 , wherein, when the recognizing the turning direction recognizes the turning direction as a left turn direction, the adjusting of the at least one control parameter based on the turning direction comprises:

reducing a push-off phase torque of a right ankle joint of the user.

13. The control method of claim 8 , wherein, when the recognizing the turning direction recognizes the turning direction as a right turn direction, the adjusting of the at least one control parameter based on the turning direction comprises:

reducing a push-off phase torque of a left ankle joint of the user.

14. The control method of claim 1 , further comprising:

recognizing a turning degree of the user based on the sensor information, wherein

the adjusting the at least one control parameter comprises adjusting the at least one control parameter based on the turning degree.

15. The control method of claim 14 , wherein the adjusting of the at least one control parameter comprises:

adjusting the gain of the rotational torque based on the turning degree such that the gain gradually decreases as the turning degree increases.

16. The control method of claim 1 , wherein the receiving of the sensor information comprises:

receiving the sensor information from one or more of an inertial sensor, an azimuth sensor, a geomagnetic sensor, and a foot sole contact sensor.

17. A non-transitory computer-readable medium comprising computer readable instructions to cause a computer to perform the control method of claim 1 .

18. A walking assistance apparatus, comprising:

a support configured to attach to a limb of a user;

a driver; and

a control apparatus including,

a communication interface configured to receive sensor information; and

a processor configured to,

instruct the driver to output, in different ones of a plurality of walking phases, a rotational torque to the support attached to the limb of the user to assist the user with straight walking, the plurality of walking phases including at least a swing phase, a stance phase, and a push-off-phase,

recognize, based on the sensor information, that the user is performing a turning operation in a turning direction while assisting the user with the straight walking through the plurality of walking phases, and

in response to the user performing the turning operation,

adjusting at least one control parameter to assist the turning operation by gradually reducing a gain of the rotational torque associated with at least one of the swing phase, the stance phase, and the push-off-phase from the gain of the rotational torque when walking straight to a value greater than zero to generate a reduced rotational torque that varies during the at least one of the swing phase, the stance phase, and the push-off-phase, and

instructing the driver to change from outputting the rotational torque to outputting the reduced rotational torque to the support in the at least one of the swing phase, the stance phase, and the push-off-phase to assist the user in performing the turning operation such that, while performing the turning operation, the rotational torque output by the driver varies during the at least one of the swing phase, the stance phase, and the push-off-phase and is reduced as compared to the straight walking.

19. The walking assistance apparatus of claim 18 , wherein the processor is configured to,

track a variable component based on the sensor information, the variable component varying in response to the walking, and

determine whether the user is performing the turning operation based on the variable component.

20. The walking assistance apparatus of claim 19 , wherein the processor is configured to,

extract a representative component from the variable component,

determine whether a variance in the representative component is maintained within a set range, and

determine that the user is performing the turning operation, if the variance exceeds the set range.

21. The walking assistance apparatus of claim 20 , wherein the variable component includes one or more of a direction that a body of the user faces during the walking and a direction that a pelvis of the user faces during the walking.

22. The walking assistance apparatus of claim 19 , wherein the variable component includes a first variable component and a second variable component, the first variable component corresponding to a motion of a left hip joint of the user, and the second variable component corresponding to a motion of a right hip joint of the user, and wherein the processor is configured to,

determine whether a variance in the first variable component and a variance in the second variable component are symmetric, and

determine that the user is performing the turning operation, if the variance in the first variable component and the variance in the second variable component are asymmetric.

23. The walking assistance apparatus of claim 18 , wherein the processor is configured to,

determine the gain of the rotational torque to assist the turning operation, and

apply the gain to the rotational torque to generate the reduced rotational torque.

24. The walking assistance apparatus of claim 18 , wherein the at least one control parameter includes one or more of a hip joint torque for each walking phase, an ankle joint torque for each walking phase, a knee joint torque for each walking phase, and a foot sole torque for each walking phase.

25. The walking assistance apparatus of claim 18 , wherein the processor is configured to,

recognize the turning direction associated with the turning operation based on the sensor information, and

adjust the at least one control parameter based on the turning direction.

26. The walking assistance apparatus of claim 25 , wherein the processor is configured to recognize the turning direction based on a z-axial rotation angle of a body part from which the sensor information is obtained.

27. The walking assistance apparatus of claim 25 , wherein the processor is configured to, when the turning direction is left,

reduce a swing phase torque of a left hip joint of the user, and

reduce a stance phase torque of a right hip joint of the user.

28. The walking assistance apparatus of claim 25 , wherein the processor is configured to, when the turning direction is right,

reduce a stance phase torque of a left hip joint of the user, and

reduce a swing phase torque of a right hip joint of the user.

29. The walking assistance apparatus of claim 25 , wherein the processor is configured to, when the turning direction is left, reduce a push-off phase torque of a right ankle joint of the user.

30. The walking assistance apparatus of claim 25 , wherein the processor is configured to, when the turning direction is right, reduce a push-off phase torque of a left ankle joint of the user.

31. The walking assistance apparatus of claim 18 , wherein the processor is configured to,

recognize a turning degree of the user based on the sensor information, and

adjust the at least one control parameter based on the turning degree.

32. The walking assistance apparatus of claim 31 , wherein the processor is configured to adjust the gain for the rotational torque based on the turning degree such that the gain gradually decreases as the turning degree increases.

33. The walking assistance apparatus of claim 18 , wherein the communication interface is configured to receive the sensor information from one or more of an inertial sensor, an azimuth sensor, a geomagnetic sensor, and a foot sole contact sensor.

34. The control method of claim 1 , wherein the adjusting of the at least one control parameter to assist the turning operation comprises:

gradually reducing a push-off phase torque associated with the push-off phase of an ankle joint of a leg opposite a turning direction of the user, in response to the user performing the turning operation in the turning direction.

35. The walking assistance apparatus of claim 18 , wherein the processor is configured to adjust the at least one control parameter to assist the turning operation by gradually reducing a push-off phase torque associated with the push-off phase of an ankle joint of a leg opposite a turning direction of the user, in response to the user performing the turning operation in the turning direction.