Frequency-Split Steering Control for Smooth Path Tracking
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Solution Overview
Problem
Existing steering control systems in vehicles with autonomous driving functions face challenges in balancing path tracking precision with smooth steering wheel motion, often leading to nervous steering behavior and increased calibration efforts, which can cause driver anxiety.
Innovation Solution
A steering control system utilizing a frequency filter unit to separate steering requests into low-pass and high-pass filtered signals, processed by distinct control units (steering angle and torque vectoring controllers) to achieve precise and smooth steering actions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single control system is used for steering, then the device complexity is low, but the steering precision and smoothness deteriorate due to nervous steering behavior
Solution Approach 1:
The control system is segmented into two independent control units: a steering angle controller for low-frequency path tracking and a torque vectoring controller for high-frequency steering stabilization. This segmentation allows each controller to specialize in specific frequency ranges, improving overall steering precision while maintaining manageable system complexity through modular architecture
Solution Approach 2:
A frequency filter unit acts as an intermediary between the steering request input and the two control units. It separates the steering request into low-pass and high-pass filtered signals, directing appropriate frequency components to each controller. This intermediary enables precise frequency-based control distribution without requiring complex communication protocols between controllers
2Manufacturing precision
If path control functions are calibrated for precision, then the steering precision improves, but the calibration time and costs increase immensely
Solution Approach 1:
The control system separates path tracking and steering stabilization into distinct control units with dedicated frequency ranges. The steering angle controller handles low-frequency path tracking while the torque vectoring controller manages high-frequency corrections, allowing each to be calibrated independently for their specific function rather than requiring comprehensive system-wide calibration
Solution Approach 2:
The frequency filter unit applies partial filtering to the steering request, separating only the necessary frequency components before they reach each controller. This partial action approach allows calibration to focus on specific frequency ranges for each controller rather than requiring full-spectrum calibration, reducing overall calibration time and effort
Data Source
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AI summary
The present disclosure relates to a steering control system for a vehicle, a vehicle comprising such a steering control system and a method for operating such a steering control system for a vehicle. The steering control system comprises a frequency filter unit, a first control unit, and a second control unit. The frequency filter unit comprises a high pass filter and a low pass filter. The frequency filter unit is configured to receive a request for a steering angle and filter the request into a low-pass filtered request and a high-pass filtered request. The first control unit is configured to determine a first controlling torque based on the low-pass filtered request the second control unit is configured to determine a second controlling torque based on the high-pass filtered request. The first control unit is different of the second control unit.