Steering Angle Detection Device Using Actuator Position Correction
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Solution Overview
Problem
Existing technologies fail to accurately calculate the turning angle of a vehicle when traveling straight due to errors in detecting rack end turning angles, which are not necessarily aligned with the median of left and right steering limits.
Innovation Solution
A turning angle detecting device is developed, including a position detecting unit, an actuator, storage units for correction values and initial positions, and calculating units to accurately determine the turning angle by using the median of rack end turning angles, actuator initial position, and actuator position to correct for errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the median of left and right rack end turning angles is used as the neutral point, then the calculation is simple, but the turning angle detection accuracy deteriorates because it does not coincide with the actual straight traveling turning angle
Solution Approach 1:
The system performs preliminary detection of rack end turning angles and storage of correction values before actual turning angle calculation. The correction value (difference between median and actual neutral point) is pre-calculated and stored in storage means, so that during normal operation, the accurate turning angle can be obtained by adding this pre-stored correction value to the calculated angle, without requiring complex real-time recalibration.
Solution Approach 2:
A correction value acts as an intermediary between the simple median calculation and the accurate neutral point. This correction value, stored in the storage means, mediates the relationship by being added to the calculated turning angle to compensate for the inherent inaccuracy of using the median as the neutral point, thus achieving accurate turning angle detection without changing the fundamental calculation method.
2Ease of operation
If rack end turning angles are detected to establish a reference, then a turning angle can be calculated, but detection errors occur that propagate to the final turning angle measurement
Solution Approach 1:
The system uses feedback by detecting the actual straight traveling turning angle (when steering wheel angle is zero), calculating the difference between this actual angle and the median of rack end turning angles, and storing this correction value. This feedback loop allows the system to identify and compensate for detection errors in future operations by applying the stored correction value to subsequent turning angle calculations.
Data Source
Figure 1
Figure 2
Figure 3A~3C
AI summary
To calculate a turning angle with respect to a turning angle when a vehicle is traveling straight with high accuracy. A turning angle detecting device includes: a first storage unit (34) configured to store a turning angle neutral point correction value being a difference between a median of the turning angles at respective limits in right steering and left steering and the turning angle when a vehicle is traveling straight; a second storage unit (34) configured to store an initial position of a movable portion of an actuator of a wheel turning mechanism when the vehicle is traveling straight; a first turning angle calculating unit (32) configured to calculate a first turning angle with respect to the median of the turning angles at the respective limits in the right steering and the left steering on a basis of a detection value of a position of the movable portion of the actuator; and a second turning angle calculating unit (35) configured to calculate a second turning angle when the vehicle is traveling straight on a basis of the detection value of the position of the movable portion of the actuator, the turning angle neutral point correction value, the initial position and the first turning angle.