Steering Rod Sensor Patterning for Absolute Position Recovery
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Solution Overview
Problem
Determining the exact position of the steering rod or individual wheel adjusters in a steer-by-wire system after vehicle restart is challenging due to ambiguity in sensor readings, especially when the vehicle is moved during shutdown.
Innovation Solution
A steering rod with parallel target lanes of conductive segments and gaps forming unique patterns, combined with a sensor system using alternating magnetic fields and multiple receiver coils, allows for unambiguous position determination by analyzing the angles of these patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a counting system is used to determine steering rod position, then the position can be ascertained during operation, but the system becomes ambiguous when the vehicle is turned off and the steering rod moves
Solution Approach 1:
The target lane is segmented into multiple conductive segments with gaps between them, forming a periodic pattern. This segmentation allows the sensor system to detect the steering rod position by measuring the angle of the alternating magnetic field signal, providing unambiguous position determination even when the steering rod moves during vehicle shutdown.
Solution Approach 2:
The patent transitions from a single-dimensional counting system to a two-dimensional measurement approach by using multiple receiver coils arranged in different spatial orientations. This allows the system to determine both the magnitude and angle of the magnetic field signal, creating a unique signature for each position of the steering rod and eliminating ambiguity.
2Extent of automation
If sensors and control units are used in a steer-by-wire system, then electronic control is enabled, but the position of the steering rod cannot be determined after vehicle restart without external reference
Solution Approach 1:
The steering rod itself serves as the reference object for position measurement. The conductive segments are rigidly connected to the steering rod, so the pattern moves with the rod. This self-referencing approach eliminates the need for external sensors or reference systems, allowing the steering rod position to be determined autonomously after vehicle restart.
Solution Approach 2:
The patent replaces mechanical position reference systems with an electromagnetic field-based measurement system. The alternating magnetic field generated by the transmitter coil interacts with the conductive segments to produce an electrical signal whose angle corresponds to the steering rod position, substituting mechanical coupling with electromagnetic sensing.
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
Enables precise, power-on determination of the steering rod's absolute or relative position without external sensors, enhancing the accuracy and robustness of steer-by-wire systems.
Implementation Method 1
a transmitter coil (30), which is set up to be energized by an alternating electric field signal
Implementation Method 2
The first receiver coil system (32, 34) comprises at least two first receiver coils, each of which is set up to receive a first alternating magnetic field signal emanating from the first target lane (12)
Implementation Method 3
each of which is set up to receive a first alternating magnetic field signal emanating from the first target lane (12)
Data Source
AI summary
A steering rod for a steer-by-wire steering system is disclosed. The steering rod is designed to move in the axial direction over a distance S. The steering rod includes a first target lane with first conductive segments. Gaps exist between the first segments such that the first segments and gaps form a first pattern along the first target lane which repeats itself with a first period length p1. The steering rod includes a second target lane with second conductive segments. Gaps exist between the second segments such that the second segments and gaps along the second target lane form a second pattern that repeats with a second period length p2. The period lengths p1 and p2 are selected such that the least common multiple of the period lengths p1 and p2 is greater than or equal to the distance S.