Wheel Speed Calculation Using Pulse Clock Timing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current wheel speed measurement devices fail to provide reliable speed measurements at low speeds, leading to inadequate detection of tire punctures or under-inflation, as they cannot position clock values correctly when the number of electrical pulses is less than the clock increments within the buffer memory period.
Innovation Solution
A method and device for calculating wheel speed using a formula that accounts for the number of electrical pulses and clock increments, allowing for speed calculation even when pulses are fewer than increments, by using the formula V(n) = 2 * πR * N * Δt / (N * T_H), where V(n) is the calculated speed, R is the wheel radius, N is the number of teeth, and Δt is the time difference between pulses, with n determined based on the number of pulses received.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the buffer memory records clock values for a fixed period (100ms) with a high-frequency clock (4MHz), then the measurement resolution is improved, but the device cannot provide speed measurements at very low speeds when the number of electrical pulses is less than the number of clock zero crossings
Solution Approach 1:
The invention changes the calculation parameters by introducing a new formula that uses the actual time difference between consecutive electrical pulses (Δt) rather than relying on fixed buffer period assumptions. The formula V(n) = 2 × πR × N × Δt / (N × T_H) dynamically adapts to low-speed conditions by calculating the actual pulse interval, allowing reliable speed measurement even when pulse count is less than clock zero crossings during the buffer period
Solution Approach 2:
The invention performs preliminary calculation of the time difference Δt between consecutive electrical pulses and uses this pre-calculated value in the speed formula. By preparing the time interval data beforehand and incorporating it into the velocity calculation, the system can accurately determine speed at low velocities without requiring a minimum threshold of pulses within the buffer period
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables reliable wheel speed measurement at very low speeds, allowing for timely detection of tire issues like punctures or under-inflation, improving the accuracy and reliability of tire pressure monitoring systems.
Implementation Method 1
a magnetic sensor comprising a toothed wheel (AD) driven in rotation at the same speed as the wheel, and a fixed detection part connected to a computer
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a wheel speed calculation method comprising the steps of: recording (E1), during a predefined period, values taken by a clock, encoded on a bit number Nb, when electrical pulses are received, and calculating (E2) a wheel speed, wherein the wheel speed is calculated when the number of received electrical pulses is less than the number of returns to the zero value of the clock, with R being the pre-recorded wheel radius, N being the number of teeth of the wheel speed sensor used, and Δt(n) = [top k - top k _ 1 + (2Nb - 1)n] * T, where topk is the kth electrical pulse clock value, and T is the period of said clock, n being such that j is the number of received electrical pulses.