Multi-function speed sensor
A smart sensor system and method for a vehicle are described. The smart sensor includes at least one sensing element installed on a suspension of the vehicle and coupled with a wheel of the vehicle, and a digital signal processing circuitry configured to receive signal from the at least one sensing element in the form of a digital signal, correlate the digital signal to an air gap data, and determine a vehicle speed, a vehicle acceleration, a suspension condition, a tire condition, a brake condition, a wheel condition, and a road condition.
1. A smart sensor for a vehicle, comprising:
a rotating component coupled to a wheel of the vehicle, the rotating component having a plane of rotation;
at least one magnetic sensing element installed on a suspension of the vehicle and separated by an air gap from the plane of rotation such that the air gap changes over time as the suspension flexes, the at least one magnetic sensing element outputting a signal corresponding to the air gap and the sensing element; and
circuitry configured to
receive the signal from the at least one magnetic sensing element,
determine air gap data based on the signal,
perform frequency analysis of the air gap data, and
determine whether the vehicle has at least one of a wheel wobble and a brake wobble based on the air gap data and the frequency analysis of the air gap data.
2. The smart sensor for a vehicle according to claim 1 , wherein the air gap data includes at least one of
an amplitude of the signal from the at least one magnetic sensing element over a period of time, and
a frequency of the signal from the at least one magnetic sensing element over a period of time.
3. The smart sensor for a vehicle according to claim 2 , wherein
the at least one magnetic sensing element is a differential hall effect sensor, and
the amplitude over a period of time is a differential amplitude from the differential hall effect sensor.
4. The smart sensor for a vehicle according to claim 1 , wherein the circuitry includes:
at least one amplifier;
at least one automatic gain controller configured to control a gain of the at least one amplifier;
at least one automatic offset adjustment;
at least one signal filter configured to filter out signals with high frequency; and
at least one analog-to-digital converter.
5. The smart sensor for a vehicle according to claim 4 , wherein the circuitry determines the air gap data from the gain of at least one amplifier.
6. The smart sensor for a vehicle according to claim 1 , wherein the frequency analysis is a fast Fourier transform or a discrete Fourier transform of the air gap data.
7. The smart sensor for a vehicle according to claim 1 , wherein the at least one magnetic sensing element is a two channel differential sensor with a first sensing element and a second sensing element.
8. The smart sensor for a vehicle according to claim 7 , wherein a signal from the second sensing element is time delayed relative to a signal from the first sensing element.
9. The smart sensor for a vehicle according to claim 2 ,
wherein the amplitude of the signal is inversely proportional to the air gap.
10. The smart sensor for a vehicle according to claim 1 ,
wherein the air gap is a linear distance between the rotating component and the at least one magnetic sensing element.