Steering Rack Offset Compensation During Straight-Line Driving
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Solution Overview
Problem
In steer-by-wire systems, incorrect rack position settings can lead to deteriorated steering feeling and steering pull phenomena, necessitating a method for real-time determination and compensation of rack position offset.
Innovation Solution
A steering control device and method that includes a receiver for vehicle information, a straight-driving determiner, short-term and long-term storages, and a determiner to calculate standard error and offset based on average values, using short-term and long-term storage periods to enhance accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rack position is set incorrectly in steer-by-wire system, then steering control can still be performed, but steering feeling deteriorates and steering pull phenomenon occurs
Solution Approach 1:
The patent implements a feedback mechanism where the rack position is continuously monitored during straight driving conditions. The system calculates the average rack position over multiple straight driving episodes and compares it against the expected neutral position. When a deviation is detected, the system automatically compensates by adjusting the rack position offset, thereby restoring proper steering feeling without requiring manual intervention or recalibration.
Solution Approach 2:
The system performs self-diagnosis and self-correction of rack position offset automatically during normal straight driving operations. By utilizing the straight driving condition as a natural calibration opportunity, the system eliminates the need for separate calibration procedures or external intervention, maintaining optimal steering feeling through autonomous adjustment.
2Measurement precision
If rack position offset is not compensated in real-time, then system complexity remains low, but steering precision deteriorates
Solution Approach 1:
The patent implements a dynamic compensation strategy where the rack position offset is continuously updated based on real-time driving conditions. The system activates calibration only during straight driving episodes, dynamically adjusting the compensation level based on the detected rack position deviation. This dynamic approach ensures high measurement precision while avoiding unnecessary computational overhead during non-calibration conditions.
Solution Approach 2:
The system changes the rack position parameter dynamically based on detected deviations. By calculating the average rack position during straight driving and comparing it to the neutral position, the system determines the required offset compensation. This parameter adjustment is performed automatically and continuously, maintaining high positioning accuracy without requiring complex control algorithms.
3Reliability
If standard error calculation is performed to filter erroneous data, then measurement reliability improves, but computational complexity increases
Solution Approach 1:
The patent applies a selective calibration approach by performing standard error calculation and offset compensation only during straight driving conditions, rather than continuously during all driving modes. This partial action approach filters out erroneous data from turning or maneuvering conditions where rack position naturally deviates, thereby improving measurement reliability while minimizing unnecessary computational complexity during non-calibration periods.
Data Source
AI summary
The embodiments relate to a steering control device and method. Specifically, a steering control device according to an embodiment may include a receiver configured to receive vehicle driving information of a host vehicle from a plurality of sensors, a straight-driving determiner configured to determine whether the host vehicle travels in a straight line based on the vehicle driving information, and determine a straight travel time, a short-term storage configured to store a first summation value obtained by summing rack positions received every predetermined period, a long-term storage configured to store a first average value of the first summation values stored in the short-team storage, and a determiner configured to determine a standard error of a rack position based on the first average value, and determine a rack position offset of the host vehicle if the standard error is less than a reference value.