Patent ID: 8544322

Claim:
A jaw motion measuring system comprising: an acceleration detector having at least an acceleration sensor that senses accelerations of three-axis directions, a flexible wire that is configured by a plurality of thin wires covered by insulating covering films being bundled together and that is light-weight and provided with flexibility to an extent of not causing accelerations sensed by the acceleration sensor to fluctuate and whose one end is connected to the acceleration sensor, an output terminal that is connected to another end of the flexible wire and outputs acceleration data of the three-axis directions, and an attachment portion that attaches the acceleration sensor to a chin portion of a lower jaw; and a jaw motion measuring device that acquires acceleration data corresponding to jaw motion from the acceleration detector, and carries out correction, with respect to the acquired acceleration data, of errors due to the acceleration sensor, and measures jaw motion expressed by acceleration waveforms, wherein, given that an X-axis direction of the acceleration sensor is made to correspond to a left-right direction of the chin portion of the lower jaw, a Y-axis direction is made to correspond to a front-back direction that is a tangent line direction of rotational motion around a rotation axis of a mandibular condyle, and a Z-axis direction is made to correspond to a vertical direction that is an extending direction of a straight line that connects the rotation axis and the acceleration sensor, the jaw motion measuring device has a position offset correcting unit that carries out a first correction, that rotates orthogonal coordinates of the acceleration sensor around a Z-axis such that acceleration data of the X-axis direction becomes a minimum, and a second correction, that rotates the orthogonal coordinates of the acceleration sensor around an X-axis such that acceleration data of the Z-axis direction becomes a minimum, and carries out correction, with respect to the acquired acceleration data, of errors due to attachment position offset of the acceleration sensor.