DEFORMATION STATE SENSING METHOD OF IN-TIRE SENSOR, TIRE TOUCH-DOWN STATE ESTIMATION METHOD, AND TIRE TOUCH-DOWN STATE ESTIMATION APPARATUS

摘要

PROBLEM TO BE SOLVED: To provide a method for stably sensing a deformation state of a sensor arranged in a tire on the car body side without using wireless communication, a method for estimating a touch-down state of a tire, and an apparatus of the same.SOLUTION: One element electrode of a piezoelectric sensor 11 arranged in a tire 3 is electrically coupled with a wheel to make the other element electrode float, and the car body side is provided with a sensing electrode 12a and a reference electrode 12b to sense charge potentials distributed over the car body, so that a charging waveform consisting of the charge potentials distributed over the car body the generation source of which is the charge charged on a tread due to the contact of the tire 3 with a road surface and the charge potentials due to a deformation state of the piezoelectric sensor 11 superposed on these charge potentials is sensed on the car body side. Further, a touch-down state of the tire is estimated from a sensed charging waveform.