Vehicle Steering Hysteresis Compensation via Feedback Control
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Solution Overview
Problem
Conventional vehicle steering systems fail to accurately account for hysteresis in steering angle sensors, leading to discontinuous steering and deviations from the target route, especially during turn-back steering, due to uncorrected hysteresis in detected steering angles.
Innovation Solution
A vehicle steering system that includes a steering mechanism, a motor, a steering angle sensor, a hysteresis estimation unit, and a control unit, which estimates and compensates for hysteresis by calculating a hysteresis estimation value and adjusting the motor control to align the detected steering angle with the target steering angle, thereby reducing hysteresis effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a steering angle sensor is used to detect steering angle, then steering angle detection is achieved, but hysteresis occurs in the detected steering angle output
Solution Approach 1:
The control unit receives feedback from the steering angle sensor and compares the detected steering angle with the target steering angle. Based on this feedback loop, the control unit calculates the hysteresis value and adjusts the motor output to compensate for the hysteresis, thereby improving the reliability of steering angle detection and control.
Solution Approach 2:
The system changes the parameter of steering angle by calculating a hysteresis value based on the difference between target and detected steering angles. This parameter adjustment compensates for the hysteresis effect in the sensor output, allowing accurate steering control despite the sensor's inherent hysteresis characteristics.
2Device complexity
If hysteresis is not corrected in detected steering angle, then steering angle detection is simple, but discontinuous steering occurs during turn-back steering
Solution Approach 1:
The control unit continuously monitors the detected steering angle and compares it with the target steering angle, creating a feedback mechanism that automatically compensates for hysteresis. This feedback approach maintains steering smoothness during turn-back operations without significantly increasing system complexity.
Solution Approach 2:
The control unit calculates the hysteresis value in advance based on the difference between target and detected steering angles, and applies compensation before the steering action is executed. This preliminary compensation prevents discontinuous steering behavior during turn-back maneuvers.
3Device complexity
If hysteresis is not corrected, then the system operates simply, but the traveling route deviates from the target route
Solution Approach 1:
The control unit uses feedback from the steering angle sensor to continuously adjust the motor output, comparing the detected steering angle with the target steering angle. This feedback mechanism ensures the vehicle follows the target route accurately by compensating for hysteresis effects.
Solution Approach 2:
The system adjusts the steering angle parameter by calculating and compensating for hysteresis values. This parameter modification ensures that the actual steering angle matches the target steering angle, thereby maintaining accurate route following without requiring complex hardware modifications.
4Measurement precision
If a small-amplitude filtration filter is used to extract vibration components, then vibration extraction is improved, but hysteresis correction is not provided
Solution Approach 1:
The system merges the vibration extraction function with the hysteresis correction function in the control unit. By combining these functions, the system achieves both accurate vibration component extraction and hysteresis correction, improving overall steering angle accuracy without requiring separate systems.
Solution Approach 2:
The control unit is designed to perform multiple functions: extracting vibration components using the small-amplitude filtration filter and simultaneously correcting hysteresis by calculating the difference between target and detected steering angles. This multi-functional approach enhances both vibration extraction accuracy and steering angle 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
The system achieves accurate and smooth steering by compensating for hysteresis, ensuring the vehicle stays on the target route without sudden changes in steering angle, thus improving steering precision and route adherence.
Implementation Method 1
a steering angle sensor that detects a steering angle, which is a rotation angle of the steering mechanism, and outputs a detected steering angle having a hysteresis with respect to the steering angle
Data Source
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AI summary
There is provided a vehicle steering system including a steering mechanism (1) that drives a vehicle, a motor (2) that makes the steering mechanism (1) rotate, a steering angle sensor (4) that detects a steering angle, which is a rotation angle of the steering mechanism (1), and outputs a detected steering angle having a hysteresis with respect to the steering angle, a hysteresis estimation unit (6) that estimates a hysteresis estimation value corresponding to a difference between the steering angle and the detected steering angle, and a control unit (7) that controls the motor (2) in such a way as to be equal to a difference between the steering angle and a target steering angle, which is a target value of the steering angle, based on the target steering angle, the detected steering angle, and the hysteresis estimation value.