Steering Angle Sensor Alignment Segmentation for Industrial Trucks

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Solution Overview

Problem

The existing alignment methods for steering angle sensors in electric steering systems of industrial trucks require excessive movement of the steered wheel, leading to stress and prolonged alignment times, especially when the system is restarted after being turned off.

Innovation Solution

A method that uses a setpoint sensor to detect the steering angle sensor position and an actual value sensor to detect the steered wheel orientation, with a transmission ratio defining the angle change of the steered wheel relative to the steering angle sensor, allowing alignment within specific segments to minimize wheel movement and reduce alignment time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the steering angle sensor is aligned by reproducing the entire angular change beyond segment limits, then the alignment accuracy is improved, but the steered wheel undergoes excessive movement and stress

Engineering Contradiction:
Improvealignment accuracyVSAvoidstress on steered wheel
Core Design Contradiction:
Measurement precisionVSStress or pressure

Solution Approach 1:

The patent divides the angular range of the steered wheel into segments, where each segment corresponds to a full rotation of the steering angle sensor (360°). During alignment, the system only needs to reproduce the angular change within the current segment rather than the entire angular range. This segmentation allows accurate alignment while limiting steered wheel movement to a manageable range, thereby reducing stress on the wheel mechanism.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If the steering angle sensor undergoes multiple full rotations during alignment, then the alignment accuracy is improved, but the alignment time is prolonged

Engineering Contradiction:
Improvealignment accuracyVSAvoidalignment time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

By dividing the alignment process into segments corresponding to 360° rotations of the steering angle sensor, the system can efficiently determine the current segment and only reproduce the necessary angular change within that segment. This avoids unnecessary full rotations and significantly reduces alignment time while maintaining accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system determines the current segment of the steered wheel before performing the alignment reproduction. This preliminary identification of the segment allows the system to calculate the exact angular change needed within that segment, avoiding unnecessary rotations and enabling faster alignment.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If the transmission ratio is increased to cover the entire angular range with fewer sensor rotations, then the alignment speed is improved, but the steering precision is reduced

Engineering Contradiction:
Improvealignment speedVSAvoidsteering precision
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent maintains a transmission ratio that requires multiple full rotations of the steering angle sensor to cover the entire angular range of the steered wheel. However, by implementing segment-based alignment, the system only needs to reproduce the angular change within the current segment (typically less than one full rotation), thereby achieving both high precision and fast alignment speed.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP1964752B1Method for adjusting the steering angle transmitter of the electrical steering for an industrial truck and an industrial truck
Publication Date: 2010.02.24 JUNGHEINRICH AG
  • EP1964752B1 patent drawingFigure 1~4

AI summary

The method involves detecting the orientation of steering wheels (20) using actual value sensors (22), and detecting position of steering angle sensors (10) with a reference value sensor (12). A steering control (14) is utilized to specify a speed ratio between steering angle sensors and the steering wheels and divide angular range of the wheels into angular segments. The steering wheels are rotated within the angular segment in an angular orientation corresponding to the position of the steering angle sensor, where the position is detected by the reference value sensor. An independent claim is also included for an industrial truck with an electrical steering and a steering angle sensor.