Planar Coil Position Determination System for 6-DOF Movement

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Solution Overview

Problem

Existing position determination systems for movement devices with six spatial degrees of freedom face challenges in achieving high spatial resolution, accuracy, and simplicity in position calculation, especially when the distance between assemblies is large, and require complex iterative calculations or cable connections for grounding.

Innovation Solution

A position determination system with planar coils or capacitor plates arranged in a grid pattern on both assemblies, allowing for electromagnetic coupling without the need for cable connections, using an inductive principle to enable precise position calculation in six spatial degrees of freedom with high-frequency fields and iterative methods like the gradient method for position determination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the distance between the first and second assemblies is made large to avoid complex iterative position calculation, then the position calculation complexity is reduced, but the magnetic forces drop quickly and position determination accuracy deteriorates

Engineering Contradiction:
Improveposition calculation complexityVSAvoidposition determination accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent changes the configuration parameters of the field interaction means from conventional arrangements to planar coil arrangements with specific geometric relationships. By optimizing the spatial arrangement and electrical characteristics of the coils, the system achieves accurate position determination at larger distances without requiring complex iterative calculations, thus resolving the contradiction between measurement precision and device complexity.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If planar coils are arranged in a grid pattern on both assemblies to enable precise position calculation, then position determination accuracy is improved, but the device complexity increases

Engineering Contradiction:
Improveposition determination accuracyVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the field interaction means into multiple planar coils arranged in grid patterns on both assemblies. Each coil acts as an independent sensing element, and the collective arrangement enables precise position calculation through electromagnetic coupling. This segmentation allows the system to achieve high measurement precision while maintaining manageable device complexity through modular construction.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The planar coils serve multiple functions: they generate electromagnetic fields for position determination, detect positional information through mutual inductance, and can be integrated into the structural design of both assemblies. This multi-functionality reduces the need for separate positioning components, thereby improving measurement precision without proportionally increasing device complexity.

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

3Stability of the object's composition

If cable connections are used for grounding the movable assembly, then electrical stability is improved, but the ease of operation and freedom of movement deteriorate

Engineering Contradiction:
Improveelectrical stabilityVSAvoidfreedom of movement
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The patent replaces the mechanical cable connection system with an electromagnetic field-based coupling system. The planar coils establish electrical connection through electromagnetic induction rather than physical contact, eliminating the need for cables. This substitution maintains electrical stability through controlled electromagnetic coupling while providing complete freedom of movement to the second assembly, resolving the contradiction between electrical stability and ease of operation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 high spatial resolution and accuracy, with measurement repetition rates up to 100 kHz and low latency, allowing the movable assembly to float freely without cable connections, while simplifying the position calculation process and reducing structural complexity.

Implementation Method 1

A position determination system is known from US Pat. No. 6,615,155 B2, which has a static first assembly and a movable second assembly. A plurality of planar coils can be arranged in the first assembly, each forming a first field interaction means. In the second assembly, on the other hand, three cylindrical coils are arranged, which are arranged in pairs orthogonally to one another. These each form a second field interaction means.

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

If there are enough corresponding pairs with a strong coupling, the desired relative position between the first and second assemblies can be calculated from the measured couplings and the specified law for the individual coupling by solving the corresponding non-linear equation system. Iterative solution methods are preferably used here, such as the gradient method

Methodology Applied
Scientific EffectElectromagnetic coupling: Electromagnetic Induction

Data Source

PatentEP3874233B1Movement device having a position determination system
Publication Date: 2022.12.07 ROBERT BOSCH GMBH
  • EP3874233B1 patent drawingFigure 1
  • EP3874233B1 patent drawingFigure 2
  • EP3874233B1 patent drawingFigure 3a~3b

AI summary

The invention relates to a movement device (10) having a position determination system (11), comprising a first assembly (20) having a first movement surface (22), and a separate second assembly (40) having a second movement surface (42), which is arranged opposite the first movement surface (22), wherein the second assembly (40) is movable with respect to the first assembly (20). The first assembly (20) comprises a plurality of planar first field interaction means (23), which are arranged distributed over the first movement surface (22) and parallel thereto, each defining a first interaction surface (24). The second assembly (40) comprises a plurality of second field interaction means (43), wherein the first and the second field interaction means (23, 43) can be brought into electromagnetic interaction. In each case, a coupling mediated via the corresponding field can be measured, wherein said couplings are taken into account in the determination of the relative position between the first and second assembly (20, 40). According to the invention, the second field interaction means (43) are each designed to be planar, wherein the second field interaction means are arranged distributed over the second movement surface (42) and parallel thereto, and wherein the second field interaction means each define a second interaction surface (44).