ゴニオメータによる書字動作の解析法

Abstract

Recently, the results of research on the brain have been looked at with fresh interest. The major reason for this is that the reference techniques for the brain have made remarkable progress. Besides, this interest has been stirred up by the fact that the abilities of future intelligent robots may approach those of the human brain. We are concerned primarily with the question of what sort of space is prepared for writing motor imagery in the brain. Thus, this paper infers the motor imagery space on the basis of motion analysis of writing. In this paper, the relation of the upper limb posture and the pen stroke in writing is analyzed. The measurement of the upper limb posture in the writing motion is carried out using an exoskeletal-type goniometer. This goniometer has ten degrees of freedom to cope with the redundancy of the natural upper limb motion. The writing goniograms indicate that the bladebone rotation is negligible and that elbow extension and flexion and shoulder rotation specify the rough letter forms. The pen stroke is shown by velocity and acceleration in the direction of the writing progression or the writing force. The writing force is obtained by taking the gauge of the strain of a phosphor bronze plate pushed up with ball-point penholder fitted into a stylus pen. According to our observation, variations of writing force are related to the motions of wrist dorsal flexion and palmar flexion, and also shoulder adduction and abduction. Further, as the result of principal component analysis, factors peculiar to the motor imagery space are extracted from the combinations of the writing goniograms. Hence, we suppose that the motor imagery space in the writing will be formed in consideration of the writing sphere relative to the shoulder position.