Non-invasive thickness measurement using capacitance measurement

A method of determining a thickness of a vehicle tire between first and second generally oppositely disposed surfaces, the method comprising:

• applying a time-varying signal to a first electrically conductive pad;
• wherein the first pad is disposed in spaced relation to a second electrically conductive pad and electrically isolated therefrom;
• wherein the second pad is grounded;
• wherein the first pad, the second pad, and the vehicle tire jointly form a capacitor;
• wherein the second surface of the vehicle tire comprises a plurality of recesses therein;
• wherein the vehicle tire is a heterogeneous material comprising a first metallic component embedded in a second dielectric component, wherein the first and second components are distinct from each other;
• determining a capacitance of the capacitor based on an electrical response of the capacitor to the application of the time-varying signal to the first pad;
• determining the thickness of the vehicle tire based on the determined capacitance;
• wherein the time-varying signal is an oscillating signal;
• wherein the first and second pads are permanently affixed to the first surface;
• wherein the first surface is an inner surface of the vehicle tire;
• wherein the determined thickness includes the thickness of the combined first metallic component and the second dielectric material;
• wherein the determining the capacitance comprises controlling a timing circuit based on the electrical response of the capacitor, and counting an output of the timing circuit to determine a frequency, and determining the capacitance based on the frequency.

A tire assembly, comprising:

• a tire comprising a dielectric material and a metal material embedded therein;
• the tire having an inner surface and an exterior surface disposed generally opposite to the inner surface;
• a first electrically conductive pad;
• a second electrically conductive pad;
• wherein the second pad is grounded;
• wherein the first and second pads are permanently affixed to the interior surface of the material;
• wherein the first pad is disposed in spaced relation to a second pad and electrically isolated therefrom;
• wherein the first pad, the second pad, and the material jointly form a capacitor;
• a processing circuit communicatively connected to the first and second pads and configured to:
• apply a time-varying signal to a first pad;
• determine a capacitance of the capacitor based on an electrical response of the capacitor to the application of the time-varying signal to the first pad;
• determine a thickness of the material based on the determined capacitance;
• wherein the determining the capacitance comprises controlling a timing circuit based on the electrical response of the capacitor, and counting an output of the timing circuit to determine a frequency, and determining the capacitance based on the frequency.