Steering Wheel Hands-On Detection with Grip and Torque Sensing
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Solution Overview
Problem
Existing systems for detecting whether a driver's hands are on or off a steering wheel face inaccuracies due to increased friction from steering column tilts, torque variations from road grooves, and difficulties in distinguishing between the driver's hand and objects with a dielectric constant, leading to incorrect hands-off state determinations and increased manufacturing costs.
Innovation Solution
A system that combines a direct sensor detecting grip area changes on the steering wheel with an indirect torque sensor to determine the hands-on or off state, using a controller to set and combine sense regions for accurate grip state determination and warning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a torque sensor is used to indirectly detect hands-on or off state, then the detection can be performed without additional sensors on the steering wheel, but friction variations from steering column tilts and road grooves cause measurement errors leading to incorrect hands-off state determination
Solution Approach 1:
The patent combines a direct sensor (capacitive or contactless) that detects hands-on state directly on the steering wheel with an indirect torque sensor that measures steering torque. By merging the detection results of both sensors, the system achieves accurate hands-on or off state determination while eliminating the measurement errors caused by friction variations from steering column tilts and road grooves that affect the torque sensor alone.
2Measurement precision
If a direct sensor is used to detect hands-on state on the steering wheel, then accurate grip detection can be achieved, but the sensor may incorrectly detect objects with dielectric constant as hands-on state and cannot detect grip on sensor-less regions
Solution Approach 1:
The system uses feedback by continuously monitoring both direct sensor output (detecting dielectric constant changes) and indirect torque sensor output (measuring steering torque). When the direct sensor detects a potential hands-on state, the torque sensor provides feedback to verify whether actual gripping force is applied. This cross-verification feedback mechanism eliminates false positives from objects with dielectric constant while maintaining reliable detection of actual grip events.
3Device complexity
If only a torque sensor is used for hands-on or off detection, then the system structure remains simple, but the detection rate and accuracy deteriorate due to torque variations from various sources
Solution Approach 1:
The patent merges a direct sensor capable of detecting hands-on state through dielectric constant or contactless methods with an indirect torque sensor measuring steering torque. This combination of sensors increases the detection rate by providing multiple detection pathways: the direct sensor detects grip intent while the torque sensor confirms actual gripping force, ensuring high detection rate without significantly increasing system complexity.
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
Enhances the accuracy and rate of hands-on or off detection, reducing false positives and negatives, and maintaining system performance by complementing the limitations of direct and indirect sensors.
Implementation Method 1
a direct sensor and an indirect sensor to detect a hands-on or off state of the steering wheel... a sensor that detects a hands-on or off state directly by being disposed in the steering wheel... variation in the dielectric constant is small
Implementation Method 2
an indirect sensor configured for detecting a hands-on sense value depending on a magnitude of a torque for rotating the steering wheel... torque sensor detects steering torque... torque variation when the driver grips the steering wheel is detected differently from the torque variation when the driver hands off from the steering wheel
Data Source
AI summary
A system for detecting hands-on or off of a steering wheel and a method thereof in which hands-on or off detecting rate and accuracy are improved by determining a hands-on or off state by interlocking a direct sensor and an indirect sensor, may include a direct sensor configured for detecting a hands-on sense value depending on a grip area of the steering wheel; an indirect sensor configured for detecting a hands-on sense value depending on a magnitude of a torque for rotating the steering wheel; and a controller connected to the first sensor and the second sensor and combining a direct hands-on sense value detected by the direct sensor and an indirect hands-on sense value detected by the indirect sensor to each other to determine a grip state of the steering wheel depending on a combined hands-on sense condition, and then to display and warn a result of determining the grip state of the steering wheel through an output unit.