Steering Wheel Hands-On Detection Under Road Torque Disturbance
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Solution Overview
Problem
Existing driver's hands on/off detection systems using torque sensors in vehicles suffer from noise interference from road conditions, leading to erroneous detections and customer complaints due to misclassification of hands on or off situations.
Innovation Solution
A method and system that utilize frequency filtering and representative value ratios from torque and vehicle-mounted sensors like longitudinal acceleration and wheel speed sensors to differentiate between disturbance and normal driving conditions, applying distinct detection logic to reduce errors and improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single torque sensor is used to detect driver's hands on/off, then the device complexity is reduced, but the measurement precision deteriorates due to noise from road conditions
Solution Approach 1:
The patent divides the detection process into two separate detection areas: a disturbance driving area and a normal driving area. By segmenting the detection based on noise conditions, the system can apply different thresholds and logic for each area, thereby improving measurement precision without significantly increasing device complexity.
Solution Approach 2:
The patent introduces a noise detection sensor as an intermediary element to detect road surface conditions. This mediator sensor provides information about the current driving environment, allowing the system to adjust its hands on/off detection thresholds dynamically based on the detected noise level, thus improving accuracy while maintaining relatively simple device architecture.
2Reliability
If the threshold for determining hands off is set low, then false hands off warnings are reduced, but true hands off situations may be erroneously detected as hands on
Solution Approach 1:
The patent implements dynamic threshold adjustment based on the detected driving area. The threshold for determining hands off is not fixed but changes dynamically according to whether the vehicle is in a disturbance driving area or a normal driving area. This dynamic adaptation allows the system to maintain high reliability while preserving measurement precision across different operating conditions.
Solution Approach 2:
The patent changes the detection parameters (thresholds) based on the driving conditions. By adjusting the torque threshold and detection logic according to the detected noise level and driving area, the system optimizes both reliability and precision for each specific operating scenario.
3Measurement precision
If the threshold for determining hands off is set high, then detection sensitivity is improved, but false hands off warnings increase due to noise
Solution Approach 1:
The system dynamically adjusts the detection threshold based on the current driving area. In disturbance driving areas with high noise, a lower threshold is applied to avoid false warnings, while in normal driving areas, a higher threshold maintains detection sensitivity. This dynamic adjustment resolves the contradiction between sensitivity and reliability.
Solution Approach 2:
The detection parameters are changed according to the driving conditions. The system monitors road surface conditions and adjusts the torque threshold accordingly, allowing high sensitivity when conditions are good and maintaining reliability when noise is present.
4Measurement precision
If a capacitive sensor is used for hands on/off detection, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent makes the existing torque sensor perform multiple functions: it detects both the driver's hands on/off status and the road surface noise conditions. By utilizing the torque sensor's measurements in a multi-functional manner with appropriate signal processing and threshold adjustment, the system achieves capacitive-sensor-level precision without adding capacitive sensors, thus maintaining device simplicity.
Solution Approach 2:
The system uses the torque sensor's own measurements to detect both steering input and road noise characteristics. The torque sensor essentially serves itself by providing data for both hands on/off detection and disturbance detection, eliminating the need for additional dedicated sensors.
Data Source
AI summary
A driver's hands on/off detection system for detecting whether a driver's hands are on/off a steering wheel during driving is applied to a vehicle. When a driving assistance system is operated by a controller during driving, the driver's hands on/off detection system calculates an electronic motor driven power steering system (MDPS) torque representative value and a vehicle measurement data representative value as a representative value ratio between sensors, and divides a disturbance driving area and a normal driving area by a magnitude of the representative value ratio between sensors to perform sensor detection correction control of a hands on/off check using a disturbance torque threshold to the torque filtering value or torque-based sensing control of a hands on/off check using an upper/lower torque limit value to the torque filtering value, thereby reducing the hands on/off detection errors during driving with only a vehicle-mounted sensor without using a capacitive sensor.