Needs for multi degrees of freedom motion measurements have been increased. The easiest way to measure multi degrees of freedom motion is to arrange several linear displacement sensors around the object. However, because of the kinematic coupling among each displacement, it demands complex signal processing algorithms, cost and time to extract displacements which users want to measure. In this paper, a new scheme to measure multi degrees of freedom motions is proposed. That is to combine sensors which are able to detect a displacement independently to displacements of other directions. To achieve that objective, the optical triangulation displacement sensor and the optical angular displacements sensor are combined. With this, the three degrees of freedom motion can be measured without kinematic couplings. The structure, model, and design scheme are suggested. To enhance a performance of the proposed system, a new signal processing algorithm based on a correlation method and a averaging method using a diffraction grating are devised and suggested. Finally, the specifications of developed prototype are as follows; the linear displacement part has 5 mm operating range and 0.5 ㎛ resolution with the signal processing algorithm, the angular displacement part has ±10° operating range, 0.1° resolution.
