CARRIER WAVE TYPE STRAIN MEASURING METHOD

• Main Author: OKANO HARUKI
• Format: Patent
• Language: English
• Published: 21.07.2005
• Edition: 7
• Subjects: MEASURING; MEASURING ANGLES; MEASURING AREAS; MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER,MECHANICAL EFFICIENCY, OR FLUID PRESSURE; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS; MEASURING LENGTH, THICKNESS OR SIMILAR LINEARDIMENSIONS; PHYSICS; TESTING

PROBLEM TO BE SOLVED: To precisely detect actual resistance components accompanying changes in resistance values corresponding to stains of a strain gage, by compensating influences of phase shifts due to stray capacitance between connection lines connecting a bridge circuit with a measuring device, while compensating initial unbalance of the bridge circuit including the strain gage which is a resistive type. SOLUTION: An initial unbalance compensating signal is input to an AC amplifier 11 so that an output voltage signal from the AC amplifier 11 inputting an output voltage signal eout from the bridge circuit 5 becomes zero in a non-strain state of the strain gage 1, and then a resistor 7 is connected to the bridge circuit 5. In above state, the amount of phase sift of the output voltage signal from the AC amplifier 11 in relation to AC supply voltage ein applied on the bridge circuit 5 is determined. When carrying out a strain measurement in such a state that the resistor 7 is disconnected from the bridge circuit 5, a signal component is detected as the resistance component, which has a phase difference from the AC supply voltage ein by the amount of phase sift being determined while inputting the initial unbalance compensating signal to the AC amplifier 11. COPYRIGHT: (C)2005,JPO&NCIPI