Movable robot comprising at least three wheel units

A movable robot (1) includes a main body unit (2), and at least three wheel units (4a,4b,4c) connected with the main body unit (2). The wheel units (4a,4b,4c) have respective contact portions (6a,6b,6c) for contact with a floor surface (8). The contact portions (6a,6b,6c) are rotatable about respective axes (3a,3b,3c). The main body unit (2) moves along the floor surface (8) as the contact portions (6a,6b,6c) rotate. Lines projected onto the floor surface and originating from the axes of rotation (3a,3b,3c) of the contact portions (6a,6b,6c) are spaced at substantially equal angular intervals &thetas;ab,&thetas;bc,&thetas;ca). At most two of the axes (3a,3b,3c) are on a common plane. Each of the wheel units (4a,4b,4c) includes a motor base, a rotation drive motor (10a,10b,10c) supported on the motor base, a casing being rotatable relative to the motor base about related one of the axes and having related one of the contact portions, and a device for transmitting a rotational force generated by the rotation drive motor to the casing.