Rotary axes and direction of rotation

The following figure shows the positive direction of rotation of rotary axes. The base is a right-handed coordinate system. If the rotation is counter-clockwise with look at the arrowhead of the coordinate system axes, the rotation is called positive. If the rotary axis is rotating around the X axis, then it is called "A axis", with rotating around the Y axis "B axis" and so on. If not separately stated, these directions of rotation are used in the kinematic transformations with rotary axes involved.