Tire Radius Diagnosis Using Wheel Angular Speeds
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Solution Overview
Problem
Current tire pressure monitoring systems (TPMS) face challenges in detecting under-inflation of multiple tires with different deflation levels, as existing methods either require costly pressure sensors or complex indirect methods that are difficult to tune and are not effective in multiple deflation scenarios.
Innovation Solution
A method that determines the real radius of each tire by comparing angular speeds using three criteria and calculates relative radii to diagnose under-inflation, allowing for the detection of multiple tires with varying deflation levels without the need for direct pressure sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If indirect SSPP methods are used to avoid pressure sensors, then manufacturing and maintenance costs are reduced, but the system complexity and difficulty of tuning increase
Solution Approach 1:
The patent segments the tire monitoring function into two parts: using existing angular velocity sensors (from stability control systems) for continuous monitoring, and supplementing with periodic direct pressure measurements only when needed. This segmentation allows the system to benefit from indirect monitoring most of the time while using direct measurement only for calibration and verification, reducing overall system complexity while maintaining accuracy
Solution Approach 2:
The patent makes the angular velocity sensors serve multiple functions: they are used both for vehicle stability control and for tire pressure monitoring. By making the monitoring system universal and multi-functional, no additional dedicated sensors are needed, reducing system complexity while maintaining the ability to detect under-inflation
2Ease of repair
If indirect SSPP methods are used to avoid pressure sensors, then maintenance costs are reduced, but the difficulty of detecting and measuring under-inflation increases
Solution Approach 1:
The patent implements feedback by using direct pressure sensor measurements to verify and calibrate the indirect angular velocity-based detection algorithm. The system continuously compares indirect measurements with periodic direct measurements, using the direct measurements to refine the indirect detection accuracy, thereby maintaining high detection capability while reducing maintenance needs
Solution Approach 2:
The system performs preliminary calibration using direct pressure sensors during tire installation or maintenance events. This preliminary action establishes baseline values that improve the accuracy of subsequent indirect monitoring, reducing the need for frequent maintenance while ensuring detection accuracy
3Ease of manufacture
If existing indirect methods are used, then pressure sensors are eliminated, but the ability to detect multiple tires with different deflation levels is insufficient
Solution Approach 1:
The patent adds a temporal dimension to the detection by analyzing angular velocity variations over time and across different driving conditions. By examining how angular velocities change during acceleration, deceleration, and steering maneuvers, the system can distinguish between multiple tires with different deflation levels, improving detection precision without adding sensors
Data Source
AI summary
The invention concerns a method for diagnosing the inflation condition of each tyre of a vehicle comprising a front pair of right and left tyres and a rear pair of right and left tyres. The main feature of a method according to the invention is that it comprises the following steps: - a first step of determining the actual radius R FL , R FR , R RL and R RR from a comparison of the angular speeds of the wheels, and from an arbitrary equation linking the four actual radii R FL , R FR , R RL , R RR together, in which R FL , R FR , R RL and R RR are respectively the radius of the front left wheel, the radius of the front right wheel, the radius of the rear left wheel and the radius of the rear right wheel; - a second step of determining the relative radius of each of the four wheels from the determination of the actual radii carried out in the previous step and from a maximum actual radius determined during the previous step; and - a step of diagnosing the inflation condition of each of the wheels from the values of the relative radii determined in the previous step.