Automatic Driving Control System Using Lateral Acceleration Thresholds
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Solution Overview
Problem
Current automatic driving systems struggle to accurately detect a driver's intention to take control of the vehicle from automatic driving mode, particularly due to subjective threshold values for torque signals, making it difficult to determine when the driver intends to manipulate the steering wheel.
Innovation Solution
The system utilizes a combination of speed sensors, yaw rate sensors, and calculating units to determine target and real-time target yaw rates and lateral accelerations, comparing these against predetermined threshold values to accurately assess the driver's intention for vehicle control, thereby enabling seamless transition from automatic to active driving mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If torque signal is used to detect driver's manipulation of steering wheel, then the system can detect driver intention, but the detection precision is insufficient because only considerable force creates sufficient torque signal
Solution Approach 1:
The patent changes the detection parameter from torque signal to lateral acceleration signal. By measuring lateral acceleration instead of torque, the system can detect driver intention through subtle steering movements without requiring considerable force, thus improving both detection precision and ease of operation.
Solution Approach 2:
The patent replaces the mechanical torque sensing system with an acceleration sensing system. Instead of using a torque sensor to detect mechanical force on the steering wheel, the system uses lateral acceleration sensors to detect the dynamic response of the vehicle when the driver manipulates the steering wheel, providing more sensitive and objective detection criteria.
2Ease of manufacture
If subjective threshold values are used for torque signals, then the system can be implemented, but the reliability is reduced due to difficulty in establishing clear objective criteria
Solution Approach 1:
By changing from torque signal to lateral acceleration signal, the patent enables the use of objective threshold values based on vehicle dynamics characteristics. Lateral acceleration has clear physical meaning and established threshold criteria, making the system both reliable and implementable without subjective judgment.
3Measurement precision
If considerable force is required to create sufficient torque signal, then the torque sensor can detect the signal, but the ease of operation deteriorates as subtle steering manipulations cannot be detected
Solution Approach 1:
The patent substitutes the mechanical torque measurement system with a dynamic acceleration measurement system. By measuring lateral acceleration, the system can detect subtle steering manipulations that generate minimal torque, as these manipulations still produce measurable lateral acceleration responses in the vehicle.
Data Source
AI summary
An automatic driving controlling system includes: a speed sensor; and a yaw rate sensor that detects a vehicle yaw rate. A controller is configured: to calculate a target yaw rate required to drive the vehicle to a target point and calculates a real-time target yaw rate by comparing a yaw rate detected in real time with the target yaw rate; to calculate a target lateral acceleration by using a vehicle speed and the target yaw rate, and calculates a real-time target lateral acceleration; and to determine whether the real-time target lateral acceleration-is out of a range between an upper limit threshold value and a lower limit threshold value of the target lateral acceleration while an automatic driving mode is in progress. The controller terminates the automatic driving mode so that the driver takes control of the vehicle to drive.