Dynamic Override Threshold for Vehicle Steering Angle
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Solution Overview
Problem
Existing override determination methods for driving assist devices do not consider the steering angle, leading to potential erroneous determinations of occupant intervention during autonomous driving.
Innovation Solution
The method involves acquiring a motor current to cancel self-aligning torque and setting a threshold value that increases with detected steering angle, determining an override when a motor current for controlling the turning angle exceeds this threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed threshold value is used for override determination, then the determination process is simple, but erroneous determination occurs when steering angle varies
Solution Approach 1:
The threshold value is changed from a fixed constant to a dynamic value that varies with steering angle. The determination unit calculates a threshold value specific to each steering angle, allowing the override determination to adapt to different steering conditions and prevent erroneous determinations.
Solution Approach 2:
The threshold parameter is modified based on the steering angle parameter. Instead of using a single fixed threshold, the system adjusts the threshold value according to the detected steering angle, ensuring accurate override determination across different steering conditions.
2Reliability
If the threshold value increases with steering angle, then erroneous determination is prevented, but the determination process becomes more complex
Solution Approach 1:
The determination unit automatically calculates the appropriate threshold value based on the detected steering angle without requiring external intervention or complex configuration. The system uses the steering angle information already available from normal operation to self-determine the threshold.
Solution Approach 2:
The determination unit performs multiple functions: it detects the steering angle, calculates the corresponding threshold value, and performs the override determination. This multi-functionality is achieved within a single control unit, avoiding the need for separate complex subsystems.
Data Source
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AI summary
A driving assist device comprises a sensor that detects the steering angle of the steering wheel 2 installed in a vehicle and a controller that determines an occupant's override with respect to driving assist control that is being executed in the vehicle based on the steering angle detected by the sensor. A controller determines a first motor current for canceling out a self-aligning torque generated in tires mounted on a vehicle while executing driving assist control, uses the first motor current to set a first threshold value that is greater than the first motor current, and determines that an override has occurred when a second motor current for controlling a turning angle of the tires in accordance with a steering angle is greater than the first threshold value.