Wheel device and mobile robot device comprising same

A mobile robot device comprising:

• a base;
• and
• a plurality of wheel devices installed on a lower portion of the base,
• wherein each wheel device of the plurality of wheel devices comprises:
• a plurality of wing members configured to rotate around a central axis, wherein each wing member of the plurality of wing members comprises an outer circumferential surface and each wing member of the plurality of wing members is configured to be movable to a first position in which the respective outer circumferential surfaces combine to form a circle, and in a second position in which each outer circumferential surface is rotated away from the central axis of the wheel device;
• a deforming device configured to move each wing member of the plurality of wing members to the first position or the second position;
• a plurality of rollers provided on the respective outer circumferential surfaces of the plurality of wing members, wherein each roller of the plurality of rollers has a rotation axis that is not parallel to the central axis;
• and
• a braking device comprising a brake pad configured to contact one or more rollers of the plurality of rollers when the plurality of wing members are in the second position and to separate from the plurality of rollers when the plurality of wing members are in the first position.