Steering Neutral Point Calibration for Straight-Travel Lane Control
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Solution Overview
Problem
Conventional lane-following driving control techniques struggle to accurately determine steering torque when the detected steering angle is zero, leading to vehicles deviating from a straight path despite assumptions of no yaw motion, making it difficult to follow lanes accurately.
Innovation Solution
A steering control apparatus that includes a steering actuator control section, a storage section for threshold steering angle information, and a calculation section to determine the neutral point of the steering angle, which is adjusted based on detected changes in loading weight to ensure accurate steering angle determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the steering angle detected by the steering sensor is assumed to be accurate when the value is zero, then the control system can determine steering torque based on this detected value, but the vehicle may actually deviate from a straight path due to neutral point deviation, reducing lane-following accuracy
Solution Approach 1:
The system performs preliminary identification of the neutral point by cyclically varying the target steering angle and detecting corresponding steering torques before actual lane-following operation. This preliminary calibration stored in the storage section enables accurate steering angle calculation during operation without requiring continuous complex measurements.
Solution Approach 2:
The system replaces direct mechanical steering angle measurement with a calculation-based approach. By substituting the detected steering angle with a calculated steering angle that compensates for neutral point deviation, the system achieves higher accuracy without adding complex mechanical sensing mechanisms.
2Device complexity
If the neutral point is not accurately identified, then the steering angle calculation can be simplified using only the detected steering angle, but the vehicle cannot travel straight and lane-following control becomes difficult
Solution Approach 1:
The neutral point identification is performed in advance through cyclic variation of target steering angle and measurement of corresponding steering torques. This preliminary action stores calibration data that simplifies subsequent steering angle calculations while ensuring reliable straight travel capability.
Solution Approach 2:
The neutral point acts as an intermediary parameter that bridges the relationship between detected steering angle and actual steering angle. By introducing this intermediate calibration value, the system achieves accurate steering control without requiring complex real-time measurement systems.
3Measurement precision
If the target steering angle is varied cyclically to identify the neutral point, then the neutral point can be accurately obtained, but this requires additional control operations and time
Solution Approach 1:
The cyclic variation of target steering angle for neutral point identification is performed as a preliminary calibration operation before normal lane-following control begins. This one-time preliminary action achieves precise neutral point identification without causing time loss during actual operation.
Solution Approach 2:
The system uses periodic cyclic variation of the target steering angle to identify the neutral point through detection of corresponding steering torques. This periodic action enables accurate identification by exploiting the periodic relationship between steering angle input and torque response.
Data Source
AI summary
A steering control apparatus and a vehicle capable of accurately obtaining a steering angle with which the vehicle will travel straight are provided. The steering control apparatus includes a steering actuator control section that controls a steering actuator for changing the steering angle such that the steering angle achieves a target steering angle, a storage section that stores threshold steering angle information regarding a threshold steering angle, which is a steering angle with which steering torque becomes a certain threshold when the target steering angle is varied cyclically and continuously, and a calculation section that obtains a neutral point of the steering angle based on the threshold steering angle information.