Vehicle Wheel Circumference Calibration via Optical Distance
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Solution Overview
Problem
Existing methods for determining the wheel circumference of a vehicle wheel are not accurate enough, leading to errors in calculating vehicle speed and distance traveled, especially when switching between summer and winter tires, and require costly and complex calibration processes.
Innovation Solution
A method involving positioning a vehicle in front of a stationary obstacle, using a distance measuring device to record a reference distance and measuring pulses from wheel revolution sensors to accurately calculate the wheel circumference, allowing for precise determination and storage for use in vehicle assistance systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the tire diameter is measured and directly programmed into the control device, then the calibration process is simple, but the accuracy of the wheel circumference determination is insufficient
Solution Approach 1:
The patent replaces manual mechanical measurement methods with an automated optical measurement system. The optical measuring device uses light-based technologies (such as laser or time-of-flight sensors) to automatically measure the distance traveled by the vehicle, eliminating the need for manual measurement and direct programming, thereby improving both accuracy and automation while simplifying the calibration process.
Solution Approach 2:
The patent introduces an intermediary computational process that correlates optical measurement data with wheel revolution sensor signals. Instead of directly programming measured values, the system uses a control device to calculate the wheel circumference by combining distance measurements from the optical device with rotation data from wheel sensors, achieving high accuracy through indirect computation rather than direct measurement.
2Measurement precision
If a reference distance is determined using complex and costly systems to achieve high accuracy, then the wheel circumference calculation becomes accurate, but the system complexity and cost increase
Solution Approach 1:
The patent makes the optical measuring device serve multiple functions: it is used both for determining the wheel circumference during calibration and for other vehicle functions such as parking assistance and distance measurement. This multi-functionality allows the system to achieve high measurement accuracy without requiring separate dedicated calibration equipment, thereby reducing overall system complexity and cost.
Solution Approach 2:
The patent enables the vehicle's existing optical measuring device to perform self-calibration by automatically determining the wheel circumference using its own measurement capabilities combined with wheel sensor data. The system calibrates itself without requiring external calibration equipment or complex procedures, achieving high accuracy through self-service operation.
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
This method provides high accuracy in determining the wheel circumference, enhancing the reliability of vehicle assistance systems like parking assistants by ensuring accurate tire parameters, such as pressure, and improving the quality of parking maneuvers.
Implementation Method 1
ascertaining the distance travelled as the reference distance with the distance measuring device
Data Source
AI summary
A method is provided for ascertaining a wheel circumference of a vehicle wheel attached to a vehicle with reference to the distance travelled by the vehicle and measuring signals of a wheel revolution sensor associated with a vehicle wheel. The method includes, but is not limited to positioning the vehicle in front of a stationary obstacle and registering the obstacle with a distance measuring device of the vehicle, moving the vehicle in direction of the obstacle, ascertaining the distance travelled as the reference distance with the distance measuring device, ascertaining the number of measuring pulses of the wheel sensor over the distance travelled, and determining the wheel circumference from the ascertained distance and the ascertained number of measuring pulses of the wheel sensor. A parking assistance system is also provided for a motor vehicle, a motor vehicle, a computer program product and a computer program.