Steering Column Tilt Estimation from Cardan Joint Bending Angles
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Solution Overview
Problem
Steering control devices without a tilt angle sensor cannot execute desired control, as they lack the necessary information to account for changes in tilt angles that affect bending angles and steering torque.
Innovation Solution
A steering computing device calculates tilt angles using mapping data and equations based on first and second bending angles between Cardan joints, allowing it to determine the axial direction of the input shaft and adjust steering operations accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If no tilt angle sensor is provided, then device complexity is reduced, but steering control precision deteriorates
Solution Approach 1:
The patent creates a virtual copy of the tilt angle sensor function by calculating the tilt angle from bending angle measurements. Instead of using a physical tilt angle sensor, the system computes the tilt angle θtl based on the relationship between bending angles and tilt angle, thereby replicating the sensor's functionality through mathematical modeling and existing sensors.
2Device complexity
If tilt angle is not measured, then device complexity is reduced, but steering control accuracy deteriorates
Solution Approach 1:
The patent replaces the mechanical tilt angle sensor with a computational system that uses bending angle sensors and mathematical relationships. The tilt angle measurement function is substituted from a direct mechanical sensing approach to an indirect computational approach based on the relationship between bending angles and tilt angle.
3Device complexity
If tilt angle changes are not accounted for, then device complexity is reduced, but actuator operation accuracy deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where the calculated tilt angle information is continuously fed back to the steering control device. This feedback allows the control system to adjust actuator operations based on tilt angle changes, ensuring accurate steering control even as the steering column tilt angle varies during vehicle operation.
Data Source
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AI summary
A steering computing device that calculates a value of a state variable about a steering apparatus (10) includes a storage device and an execution device. The execution device is configured to execute a bending angle acquisition process and a tilt angle calculation process, and the bending angle acquisition process is a process of acquiring a first bending angle and a second bending angle. The tilt angle calculation process is a process of calculating a tilt angle. The first bending angle is an angle formed between an input shaft of the steering apparatus (10) and an intermediate shaft (18) of the steering apparatus (10). The second bending angle is an angle formed between an output shaft of the steering apparatus (10) and the intermediate shaft (18), and the tilt angle is a variable indicative of an angle formed between an axial direction of the input shaft and a reference direction.