Vehicle Steering Torque Correction for Hands-Off Detection
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Solution Overview
Problem
Existing lane keeping assistance systems (LKAS) face inaccuracies in estimating the steering state of a driver due to noise factors beyond vehicle pitching, such as torque noise from electric power steering and self-aligning torque, which affect the accuracy of hands-off state determination.
Innovation Solution
A vehicle control apparatus that includes a sensor to detect steering torque, a steering assistance unit, and a processor to correct the torque by removing noise components, including torque noise and offset torques, to accurately determine the driver's hands-off state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the steering state is estimated by detecting steering torque and removing noise related to vehicle pitching, then the estimation accuracy is improved, but other noise factors such as torque noise from electric power steering and self-aligning torque are not sufficiently removed, resulting in insufficient estimation accuracy
Solution Approach 1:
The patent segments the steering torque into multiple distinct components: driver's torque, torque noise from electric power steering, self-aligning torque, and torque due to vehicle pitching. By identifying and separating each component, the system can selectively remove specific noise factors while preserving the driver's actual steering input, thereby improving estimation accuracy without oversimplifying the torque analysis.
Solution Approach 2:
The patent introduces an intermediary processing step that uses vehicle state information (such as acceleration, steering angle, and speed) to dynamically estimate and subtract noise components from the detected steering torque. This intermediary calculation layer acts as a mediator between the raw torque sensor data and the final hands-off determination, enabling more precise noise removal adapted to real-time driving conditions.
2Reliability
If the lane keeping assistance system stops when the driver is not operating the steering wheel, then safety is improved, but false stopping due to inaccurate hands-off detection may occur, reducing system reliability
Solution Approach 1:
The patent implements a feedback mechanism where the estimated noise components are continuously updated based on vehicle state changes and fed back into the torque correction process. This feedback loop allows the system to adapt to varying driving conditions and maintain accurate hands-off detection despite changes in vehicle dynamics, thereby improving reliability while compensating for noise interference.
Solution Approach 2:
The patent dynamically adjusts the noise removal parameters based on vehicle operating conditions such as speed, acceleration, and steering angle. By changing the parameters according to the current driving state, the system optimizes the noise removal process for different scenarios, improving hands-off detection accuracy and preventing false stopping of the lane keeping assistance system.
Data Source
AI summary
A vehicle control apparatus is provided. The apparatus comprises a sensor to detect a steering torque applied to a steering shaft that rotates in accordance with a steering wheel operation; a steering assistance unit configured to assist steering by a lane keeping assistance function; a correcting unit configured to obtain a corrected torque by removing a torque caused due to the steering assistance unit from the steering torque detected by the sensor; and a determining unit configured to determine whether or not a driver is in a hands-off state based on the corrected torque.