Soil Evaluation Sensor Impedance Phase Reconstruction

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Solution Overview

Problem

Existing soil evaluation systems are affected by measurement accuracy issues in determining soil impedance, which impacts the accuracy of water content and electrical conductivity calculations.

Innovation Solution

A soil evaluation system with multiple sensor units and a control unit that provides AC input signals to the soil, allowing for independent and cooperative operations to calculate impedance characteristics, reducing measurement errors by deriving phase from absolute value measurements and using time division processing to cover wide target regions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If both absolute value and phase of impedance are measured directly, then complete impedance information is obtained, but measurement accuracy is affected by errors in both measurement channels

Engineering Contradiction:
Improveimpedance measurement accuracyVSAvoidmeasurement system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts only the absolute value measurement channel and removes the phase measurement channel. The phase information is then reconstructed mathematically from the absolute value measurements taken at different frequencies, thereby eliminating phase measurement errors while maintaining complete impedance characterization capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the measurement parameter from direct phase measurement to frequency-dependent absolute value measurement. By measuring impedance magnitude at multiple frequencies and using mathematical relationships, the phase information is derived indirectly, transforming a direct measurement problem into a calculation-based solution that avoids measurement errors.

Inventive Principle:
Principle #35Parameter changes

2Area of stationary object

If multiple sensor units operate independently, then measurement coverage is limited to individual sensor ranges, but system complexity and synchronization requirements increase

Engineering Contradiction:
Improvemeasurement coverage areaVSAvoidsynchronization system complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent divides the measurement system into multiple independent sensor units, each capable of autonomous operation. Each sensor unit measures impedance characteristics in its local region independently, and the results are integrated to form a complete picture of the entire measurement area, avoiding the need for complex synchronization between units.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each sensor unit is designed with universal functionality to operate both independently and in coordination with other units. The same hardware and measurement protocol can be used whether a single sensor or multiple sensors are deployed, providing flexibility in system configuration without requiring different synchronization mechanisms.

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

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 system achieves accurate soil evaluation with reduced measurement errors and expanded measurement ranges without gaps, enabling effective water content and total ion concentration assessments in two- and three-dimensional regions.

Implementation Method 1

a first electrode portion that includes a pair of electrode ends disposed in the soil and that provides an AC input electrical signal to the soil and receives an output electrical signal from the soil

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP3872483B1Soil evaluation sensor, soil evaluation system, electrode for soil evaluation sensor, and device for obtaining impedance characteristic of soil
Publication Date: 2023.10.18 NAT UNIV CORP SHIZUOKA UNIV
  • EP3872483B1 patent drawingFigure 1
  • EP3872483B1 patent drawingFigure 2(a)~2(c)
  • EP3872483B1 patent drawingFigure 3

AI summary

A soil evaluation sensor 1 includes: a voltage generation unit 4 for generating an AC voltage; an electrode end 2 for providing the AC voltage to soil 100a; an electrode end 3 for receiving an AC current due to the AC voltage; a current measurement unit 6 for measuring the magnitude of the AC current; and a processing unit 7 for obtaining an evaluation value indicating the characteristics of the soil 100a by using the AC current obtained by the current measurement unit 6. The processing unit 7 includes: a first calculation unit 11 for obtaining first information, which indicates a relationship between the frequency of the AC voltage and the absolute value (|Z|) of impedance of the soil 100a, by using the AC voltage and the AC current; a second calculation unit 12 for calculating second information, which indicates a relationship between the frequency of the AC voltage and the phase (θ) of the impedance of the soil 100a, by using the first information; and a third calculation unit 13 for obtaining an evaluation value of the soil by using the first information and the second information.