Steering Wheel Inertia Detection for Stable Autonomous Steering
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Solution Overview
Problem
In autonomous driving systems, the varying moments of inertia in the steering wheel arrangement due to different driver interactions and the absence of driver input lead to unstable steering behavior and overshooting, as conventional position control arrangements assume a fixed moment of inertia, which is not accurate.
Innovation Solution
A method to determine the natural frequency and moment of inertia of the steering wheel arrangement using electromotive steering interventions, allowing for dynamic adjustment of the steering position control to account for the actual moment of inertia, thereby preventing oscillations and ensuring stable steering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed moment of inertia is assumed in the position control arrangement, then the control system is simple to implement, but the steering behavior becomes unstable and overshooting occurs due to varying actual moments of inertia
Solution Approach 1:
The patent applies the dynamics principle by transitioning from a static, fixed moment of inertia assumption to a dynamic approach where the moment of inertia is continuously determined during operation. The system uses electromotive steering interventions and measures the resulting angular acceleration to calculate the actual moment of inertia in real-time, allowing the control arrangement to adapt to varying driver interactions and steering conditions, thereby preventing instability and overshooting while maintaining reasonable system complexity
Solution Approach 2:
The patent implements feedback by measuring the angular acceleration of the steering wheel arrangement during electromotive steering interventions and using this information to determine the actual moment of inertia. This feedback loop allows the position control arrangement to continuously update its understanding of the system's inertial properties and adjust control parameters accordingly, ensuring stable steering behavior despite varying driver inputs
2Extent of automation
If electromechanical steering intervention is used to implement desired steering movement, then autonomous driving functions can be achieved, but vibrations occur at the steering wheel leading to unstable driving behavior
Solution Approach 1:
The patent applies dynamics by using the actual, dynamically determined moment of inertia in the position control arrangement to predict and compensate for vibrations caused by electromechanical steering interventions. By calculating the expected angular acceleration based on the intervention torque and actual moment of inertia, the system can adjust the steering command to minimize oscillations and vibrations, enabling stable autonomous driving operation
Solution Approach 2:
The patent implements preliminary anti-action by using the determined moment of inertia to predict vibration-prone steering interventions before they occur. The position control arrangement uses this information to pre-adjust the steering command, applying counteracting torque to prevent oscillations and vibrations before they manifest, thereby eliminating harmful vibrations while maintaining autonomous driving functionality
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 enables precise control of the steering system, preventing overshooting and maintaining stability during autonomous driving by accurately determining and accounting for the moment of inertia, thus enhancing the control quality and dynamics of the steering position control operation.
Implementation Method 1
a steering intervention force or a steering intervention torque is prespecified to act on the steering system by a steering drive
Implementation Method 2
a moment of inertia of the steering wheel arrangement comprising the steering wheel and the steering shaft is determined on the basis of the electromotive steering intervention
Implementation Method 3
a moment of inertia of the steering wheel arrangement comprising the steering wheel and the steering shaft is determined on the basis of the electromotive steering intervention
Data Source
AI summary
A method for operating a transportation vehicle function based on a natural frequency and/or a moment of inertia of a steering wheel arrangement in a steering system including prespecifying an electromotive steering intervention to move the steering system by providing a steering intervention force or a steering intervention torque; ascertaining a natural frequency and/or a moment of inertia of the steering wheel arrangement depending on the response of the steering wheel arrangement based on the electromotive steering intervention; and operating the transportation vehicle function based on the ascertained natural frequency and/or the ascertained moment of inertia of the steering wheel arrangement.