Tire Circumference Classification for Automated Parking Accuracy
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Solution Overview
Problem
Automatic parking systems face inaccuracies due to deviations in tire circumference measurements, which can lead to poor parking results, especially after tire changes, as existing methods suffer from relative errors of up to 3% compared to the required 1% accuracy.
Innovation Solution
A method and device that classify tires into classes with non-overlapping circumferential intervals, allowing for precise determination of tire circumference by assigning tires to classes based on estimated size, reducing systematic errors and improving accuracy to within the tolerance range of the class deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If tire circumference is measured using yaw rate and rotational speed, then tire circumference can be determined, but measurement precision deteriorates with relative errors of up to 3%
Solution Approach 1:
The patent divides the continuous range of possible tire circumferences into discrete classes with non-overlapping intervals. Each class represents a specific tire size category (e.g., standard, winter, performance tires). The system determines which class the installed tires belong to by comparing measured circumference against class boundaries, rather than attempting to measure the exact continuous value. This segmentation approach resolves the contradiction by transforming an imprecise continuous measurement problem into a discrete classification problem where 3% error tolerance is sufficient to identify the correct class.
Solution Approach 2:
The patent changes the measurement parameter from exact continuous circumference value to discrete class membership. Instead of requiring precise measurement of the actual circumference (which suffers from 3% error), the system measures circumference and maps it to discrete tire size classes. This parameter transformation allows the system to work within the 3% error tolerance while achieving sufficient precision for parking trajectory calculation.
2Adaptability or versatility
If medium tire size is assumed for all vehicles, then device complexity is reduced, but adaptability deteriorates when different tire sizes are installed
Solution Approach 1:
The patent performs preliminary classification of tires into discrete size classes based on manufacturer specifications and typical tire options for each vehicle model. This classification information is stored in advance, and the system only needs to determine which pre-defined class the installed tires belong to. This preliminary action resolves the contradiction by preparing the classification framework beforehand, so that during operation the system only needs to identify the correct class rather than handle all possible continuous variations in tire size.
Solution Approach 2:
The patent creates a universal tire classification system that can accommodate multiple tire sizes and types (standard, winter, performance) within a single framework. The discrete class structure serves as a universal categorization that works for all tire variants on a given vehicle model, eliminating the need for separate measurement and compensation systems for each tire type. This universal classification resolves the contradiction by providing adaptability across different tire sizes without proportionally increasing system complexity.
3Manufacturing precision
If exact tire circumference is required for parking accuracy, then parking precision is improved, but measurement reliability worsens due to systematic errors from tire changes
Solution Approach 1:
The patent implements a feedback mechanism where the system continuously monitors tire circumference measurements and compares them against the expected values for the identified tire class. When a tire change is detected (indicated by circumference values falling outside the expected range for the current class), the system updates the tire class assignment and recalibrates the parking trajectory calculations. This feedback loop resolves the contradiction by allowing the system to adapt to tire changes while maintaining parking accuracy, rather than requiring perfect initial measurement.
Solution Approach 2:
The patent makes the tire circumference parameter dynamic rather than static. Instead of assuming a fixed tire size, the system continuously updates the effective tire circumference based on the identified tire class and adjusts parking trajectory calculations in real-time. This dynamic adaptation resolves the contradiction by allowing the system to maintain high parking precision even when tire changes occur, as long as the tire class identification remains accurate within the 3% error tolerance.
Data Source
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AI summary
The present invention relates to a method for determining the circumference of the tyres fitted on a vehicle, in which the circumference of the fitted tyres is estimated within a predetermined tolerance band (TB11, TB21, TB31). In so doing, the tyres which can be fitted on the vehicle are divided into at least two defined classes (K1, K2), each with predetermined circumferential intervals (UK1, UK2), such that the circumferential intervals (UK1, UK2) of the two classes (K1, K2) do not overlap and in each case have an interval variable smaller than the tolerance band (TB11, TB21, TB31) of the estimated circumference of the fitted tyres. Furthermore, the fitted tyres are assigned to one of the two classes (K1, K2) with the aid of their estimated circumference. The circumference of the fitted tyre is thus determined with the aid of the specific class allocation of the fitted tyre.