US 7,320,253 B2
Stress detection method for sensor device with multiple axis sensor and sensor device employing this method
Toshio Hanazawa, Kanagawa (Japan); Masaaki Ono, Kanagawa (Japan); Tsutomu Miyashita, Kanagawa (Japan); Hiroshi Tokunaga, Kanagawa (Japan); and Hiroshi Ishikawa, Kawasaki (Japan)
Assigned to Fujitsu Media Devices Limited, Yokohama (Japan); and Fujitsu Limited, Kawasaki (Japan)
Filed on Mar. 08, 2005, as Appl. No. 11/73,944.
Claims priority of application No. 2004-109344 (JP), filed on Apr. 01, 2004; and application No. 2004-206434 (JP), filed on Jul. 13, 2004.
Prior Publication US 2005/0229720 A1, Oct. 20, 2005
Int. Cl. G01P 15/125 (2006.01)
U.S. Cl. 73—862.042  [73/1.37; 73/1.38; 73/1.77; 73/1.78; 73/493; 73/504.02; 73/862.043] 11 Claims
OG exemplary drawing
 
1. A stress detection method for a sensor device with a multiple axis sensor comprising, as the multiple axis sensor, first and second sensors having detection axes of which are orthogonal to one other,
wherein, when the detection axis of the first sensor forms an angle θ with the axis direction in which detected stress Ax is delivered, and the stress component of an axis direction that is perpendicular to the axis in which the detected stress Ax is delivered as Az,
an output Apx of the axis direction of the first sensor is found as Apx=αx (Ax ×cos θ+Az×sin θ), and
an output Apz of the axis direction of the second sensor is found as Apz=αz (Ax×sin θ+Az×cos θ), and, when αx and αz are detection sensitivity coefficients of the first and second sensors respectively, the detection sensitivitycoefficient αz of the second sensor is set as αzx tan θ,the difference Apx−Apz between the output Apx and output Apz is found, and the detected stress Ax is found from the difference as Ax=(Apx−Apz)/αx(cos θ−tan θ×sin θ).