Steering Holding Determination Device for Vehicles
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Solution Overview
Problem
Conventional electric power steering systems face challenges in accurately judging the steering holding state due to noise in motor rotational angle signals, leading to erroneous judgments and unnecessary power consumption, especially when transitioning from steer-forward to steering holding state, and struggle to detect transitions quickly enough to release current limiting.
Innovation Solution
The system employs at least two steering angle sensors to detect the steering angle and a steering state judging section that calculates a hysteresis central value from the steering signals, allowing for immediate and accurate detection of steering states without filter processing, even with noisy signals, and adjusts current limiting accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If filter processing is applied to remove noise from steering angle signals, then measurement precision is improved, but response time deteriorates
Solution Approach 1:
The patent extracts only the essential features needed for steering state judgment (steering angle magnitude and change rate) while discarding noisy components. By using multiple sensors and hysteresis comparison, the system obtains clean state information without applying traditional filter processing that would delay response.
Solution Approach 2:
The system performs preliminary judgment of steering state transitions by comparing current sensor readings against previously determined states and hysteresis thresholds. This preliminary action allows immediate state identification upon transition occurrence, eliminating the need for post-transition filter processing and achieving both speed and accuracy.
2Use of energy by moving object
If current limiting is applied during steering holding state, then power consumption is reduced, but steering responsiveness deteriorates
Solution Approach 1:
The patent dynamically adjusts current limiting based on real-time steering state detection. When transitioning from steer-forward to steering holding state, the system detects the state change immediately and applies current limiting. When transitioning back to steer-forward, current limiting is released immediately. This dynamic adaptation ensures power savings during holding while maintaining responsiveness during active steering.
Solution Approach 2:
The system uses feedback from multiple steering angle sensors to continuously monitor steering state and adjust current limiting accordingly. The feedback loop detects state transitions and modifies current command values in real-time, ensuring that current limiting is applied only when appropriate (during holding state) and released immediately when steering action is detected, thus balancing power consumption and responsiveness.
3Device complexity
If single steering angle sensor is used, then device complexity is reduced, but reliability deteriorates due to noise-induced erroneous judgments
Solution Approach 1:
The patent segments the sensing function by using multiple steering angle sensors instead of relying on a single sensor. Each sensor provides independent measurements, and the system integrates these measurements to make robust state judgments. This segmentation reduces the impact of individual sensor noise and prevents erroneous judgments, improving reliability without significantly increasing overall system complexity.
Solution Approach 2:
The system implements feedback mechanisms that compare readings from multiple sensors and use hysteresis comparison to determine steering state. This feedback approach cross-validates sensor data, ensuring that transient noise from any single sensor does not trigger false state transitions. The redundant sensing combined with feedback processing significantly improves judgment reliability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach prevents unnecessary power consumption and heat generation by accurately limiting current during steering holding states and quickly releasing current limiting when transitioning from steering holding to steer-forward, enhancing the system's responsiveness and accuracy.
Implementation Method 1
a column input-side angle signal θs1 and a column output-side angle signal θr1 from angle sensors which are provided with a column shaft
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
[Problem] An object of the present invention is to provide a steering holding judging apparatus for a vehicle that detects or does not erroneously judge a steering holding state under various circumstances, can accurately and immediately detect a steering holding state even though a noise is superimposed to a signal which uses to a detection, and can appropriately perform the current limiting of the motor, and an electric power steering apparatus equipped with the steering holding judging apparatus for the vehicle. [Means for solving the problem] The present invention is the steering holding judging apparatus for the vehicle comprising: at least two steering angle sensors to detect a steering angle; and a steering state judging section to calculate a hysteresis central value by using a hysteresis signal that sets a hysteresis width to the two steering angle sensor, judge a steering state using the hysteresis central value, and output provisional steering information, wherein a steering holding state is detected based on the provisional steering information, and the electric power steering apparatus equipped with the steering holding judging apparatus for the vehicle.