Guide Wire Signal Control for Accurate Floor Vehicle Positioning

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Solution Overview

Problem

Self-propelled vehicles used for ground or floor maintenance face inaccuracies in positioning due to alterations in the electromagnetic field generated by guide wires, leading to potential failure in reaching charging bases, and are susceptible to electromagnetic disturbances and resistance changes in the guide wire.

Innovation Solution

A control unit and method that adjust the voltage and current of the driving signal based on measured resistance to maintain a constant electromagnetic field intensity, using a Buck converter and H-bridge configuration, and include auxiliary signals for precise positioning and charging, ensuring robust signal transmission and accurate vehicle positioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the guide wire resistance is used directly for positioning, then the system is simple, but positioning accuracy deteriorates due to resistance alterations

Engineering Contradiction:
Improvepositioning accuracyVSAvoidcontrol unit complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The control unit continuously measures the guide wire resistance and uses this feedback to dynamically adjust the driving signal characteristics. The measured resistance value is fed back to the control unit, which then modifies the driving signal voltage or current to compensate for resistance changes, thereby maintaining constant electromagnetic field intensity and ensuring accurate positioning throughout the guide wire's operational life.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system changes the parameters of the driving signal (voltage or current) based on the measured guide wire resistance. By adjusting these electrical parameters in real-time, the system compensates for resistance alterations in the guide wire, maintaining constant electromagnetic field intensity and positioning accuracy without requiring a completely new positioning methodology.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the driving signal voltage is increased to compensate for resistance changes, then electromagnetic field intensity is maintained, but energy consumption increases

Engineering Contradiction:
Improveelectromagnetic field stabilityVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system dynamically adjusts the driving signal characteristics based on real-time resistance measurements rather than using a fixed high voltage. The control unit continuously adapts the voltage or current level to match the actual guide wire resistance, maintaining constant electromagnetic field intensity only when necessary and reducing energy consumption when resistance is low or stable.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The feedback mechanism allows the system to respond only when resistance changes actually occur. The control unit monitors resistance continuously and adjusts the driving signal only when compensation is needed, avoiding unnecessary energy consumption during periods when the guide wire resistance is within acceptable ranges or changes are minimal.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If electromagnetic field intensity is kept constant by adjusting driving signal, then positioning accuracy is maintained, but system complexity increases

Engineering Contradiction:
Improvepositioning accuracyVSAvoidsignal adjustment mechanism
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The control unit performs multiple functions: it measures guide wire resistance, processes the resistance data, determines appropriate compensation levels, generates adjusted driving signals, and monitors system performance. By consolidating these functions into a single multi-functional control unit, the system achieves constant electromagnetic field intensity without proportionally increasing overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses the guide wire's own resistance characteristic as the basis for its own compensation mechanism. The control unit measures the resistance of the guide wire it is already using for positioning and automatically adjusts the driving signal based on this self-diagnosis, eliminating the need for external calibration equipment or additional reference systems.

Inventive Principle:
Principle #25Self-service

4Measurement precision

If the control unit continuously monitors resistance, then positioning accuracy is maintained, but processing requirements increase

Engineering Contradiction:
Improvepositioning accuracyVSAvoidprocessing energy
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The control unit performs resistance measurements and signal adjustments at periodic intervals rather than continuously. This periodic operation maintains positioning accuracy by detecting resistance changes when they occur, while significantly reducing processing energy consumption by allowing the system to operate in lower-power states between measurement cycles.

Inventive Principle:
Principle #19Periodic action

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

The solution ensures precise and safe positioning of self-propelled vehicles, maintaining accurate navigation and charging efficiency despite changes in guide wire resistance and electromagnetic interference, enhancing operational reliability and accuracy.

Implementation Method 1

a given electrical signal is transmitted as a result of an electromagnetic field diffusion that can be received by receivers on board the self-propelled vehicle

Methodology Applied
Scientific EffectElectromagnetic field diffusion: Electromagnetic Induction

Implementation Method 2

a resistance measurement stage (303), connected to the output (301), configured to measure an electrical resistance (R) of the wire (201) when connected with the output (301)

Methodology Applied
Scientific EffectElectrical resistance measurement: Ohm's Law

Data Source

PatentEP4079132B1Unit for controlling a self-propelled vehicle for maintenance operations of a ground or a floor and associated controlling method
Publication Date: 2023.08.16 STIGA S P A IN BREVE ANCHE ST SPA
  • EP4079132B1 patent drawingFigure 1
  • EP4079132B1 patent drawingFigure 2
  • EP4079132B1 patent drawingFigure 3~4

AI summary

The present invention relates to a control unit (300) for controlling a self-propelled vehicle (10), electrically connectable with at least one wire (201) delimiting a ground or floor (100) on which the self-propelled vehicle (10), when in use, carries out maintenance. The control unit (300) comprises at least one output (301) configured to be connected to the wire (201) and on which, when in use, a driving signal (30) is fed for the self-propelled vehicle (10), a power stage (302) connected to the output (301) and configured to feed the driving signal (30) on the output (301), and a resistance measurement stage (303), connected to the output (301), configured to measure an electrical resistance (R) of the wire (201) when connected to the output (301). According to the invention, the control unit (300) envisages an operational measurement configuration and an operational power supply configuration. In the operational measurement configuration, the control unit (300) varies, through the power stage (302), the voltage and/or the current of the driving signal (30) according to the electrical resistance (R) measured by the resistance measurement stage (303). In the operational power supply configuration, the control unit (300) performs, through the power stage (302), at least one generation step of a driving signal (30) for the self-propelled vehicle (10).