Steering Wheel Sensor Calibration for Small-Target Detection
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Solution Overview
Problem
Existing vehicle steering wheels with detection sensors struggle to reliably measure contact or proximity to small targets due to manufacturing variations, leading to compromised detection thresholds and accuracy.
Innovation Solution
A calibration method involving a reference environment measurement to adjust and record initial thresholds, ensuring reliable detection of small targets by accounting for manufacturing variations and storing reference signal levels in the electronic control unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If detection thresholds are set with tolerances to account for manufacturing variations, then reliability across mass-produced steering wheels is improved, but detection precision for small targets deteriorates
Solution Approach 1:
The patent applies preliminary action by performing calibration measurements during the manufacturing process to establish reference signal levels before the steering wheel is installed in the vehicle. This advance calibration allows the system to store compensation values that will be used during operation, enabling small target detection while accounting for manufacturing variations. The calibration is performed using a reference environment and reference target to establish baseline measurements for each individual steering wheel.
Solution Approach 2:
The patent changes the detection threshold parameter dynamically based on calibration measurements. Instead of using fixed thresholds, the system determines individual reference signal levels during manufacturing and adjusts thresholds accordingly. This parameter adaptation allows the system to maintain high detection precision for small targets while compensating for manufacturing variations in sensor sensitivity, target distance, and environmental conditions.
2Device complexity
If fixed detection thresholds are used to simplify the system, then device complexity is reduced, but measurement precision for small targets deteriorates
Solution Approach 1:
The system performs preliminary calibration during manufacturing to pre-determine optimal detection thresholds for each steering wheel. This advance preparation stores reference values that simplify operation during actual use, eliminating the need for complex real-time adjustments while maintaining high detection precision. The calibration data is stored in memory and automatically applied during vehicle operation.
3Measurement precision
If individual calibration measurements are performed for each steering wheel, then measurement precision is improved, but manufacturing time and complexity increase
Solution Approach 1:
The calibration process is integrated into the manufacturing workflow as a preliminary step, performing measurements and storing reference values before the steering wheel leaves the production line. This approach consolidates the calibration activity into a standardized pre-production process, enabling automated high-speed measurements and eliminating the need for manual calibration later, thereby maintaining manufacturing efficiency while achieving individualized precision calibration.
Data Source
AI summary
A method for calibrating a measuring device for a vehicle steering wheel, the measuring device comprising a detection sensor, and an acquisition unit, the calibrating method comprising the steps of: placing the vehicle steering wheel with the on-board detection sensor in a reference environment, carrying out a reference measurement, recording the level of the reference signal and/or adjusting and recording at least one initial threshold to be used by the electronic control unit to initiate a driver assistance action, depending on the level of the measured reference signal and/or recording a difference between the level of the reference signal and the initial threshold.