Magnetic Alignment System Using Force Sensor for Planar Motor

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing magnetic alignment systems for moving-coil magnetic-levitation planar motors face inaccuracies in determining the initial angle of magnetic alignment, leading to crosstalk between horizontal and vertical directions, which degrades servo performance due to non-linear factors and limited sensor resolution.

Innovation Solution

A magnetic alignment system utilizing a magnet array, a motor rotor with four coil assemblies arranged in a matrix, and a force sensor unit to measure forces in multiple directions, allowing for precise determination and servo-correction of magnetic alignment angles, thereby improving accuracy and decoupling between directions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a capacitive or inductive distance sensor is used to measure deformation of a compressible material, then the magnetic alignment angle can be determined, but the measurement precision is insufficient due to limited sensor resolution and non-linear deformation

Engineering Contradiction:

Improvemagnetic alignment angle accuracyVSAvoidlinearity between force and deformation

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent replaces the mechanical compression measurement system (compressible material + distance sensor) with a force sensor that directly measures force. This substitution eliminates the non-linear mechanical deformation chain and provides direct, linear force measurement with higher precision, resolving the contradiction between measurement precision and reliability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The force sensor acts as an intermediary that directly couples the motor rotor to the measurement system, providing accurate force data without relying on the non-linear compression characteristics of elastic materials. This intermediary measurement approach improves both precision and reliability.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the vertical force is too large or too small, then the linearity between force and deformation becomes insufficient, but the measurement system still attempts to measure

Engineering Contradiction:

Improvelinearity of measurementVSAvoidmagnetic alignment angle accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

By replacing the compressible material-based measurement system with a direct force sensor measurement system, the patent eliminates the non-linear force-deformation relationship entirely. The force sensor provides linear measurement across the full operating range, resolving the contradiction between reliability and precision that arises at extreme force levels.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If additional sensors are added to improve measurement accuracy, then the magnetic alignment precision can be improved, but the device complexity increases

Engineering Contradiction:

Improvemagnetic alignment angle accuracyVSAvoidnumber of sensors

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces multiple sensors (compressible material layer + capacitive/inductive distance sensor) with a single force sensor that provides equivalent or superior measurement capability. This substitution reduces device complexity while maintaining or improving measurement precision.

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

The system enhances magnetic alignment accuracy by using a force sensor with a reliable linear operating range, measuring both horizontal and vertical forces, and preventing positional deviations, resulting in improved servo performance without additional sensors.

Implementation Method 1

measure a force generated by the one of the four coil assemblies under an effect of the magnetic field

Methodology Applied

Scientific EffectElectromagnetic force: Lorentz Force

Data Source

PatentEP2950441B1Magnetic alignment system and alignment method therefor

Publication Date: 2018.03.14 SHANGHAI MICRO ELECTRONICS EQUIP (GRP) CO LTD

Figure 1~2
Figure 3~4
Figure 5

AI summary

A magnetic alignment system is disclosed, including a magnet array (10), a motor rotor (20), a fixed tooling (30) and a force sensor (40). The motor rotor (20) is disposed over the magnet array (10) and is connected via the force sensor (40) to the fixed tooling (30) that is positionally fixed relative to the magnet array (10). By varying an angle of a three-phase current supplied to a specific one of three-phase coil assemblies in the motor rotor (20) within an angular range for magnetic alignment and measuring a force generated by the specific one of three-phase coil assemblies using the force sensor (40), an angle of magnetic alignment for the specific one of three-phase coil assemblies is determinable based on the angle of three-phase current that causes the specific one of three-phase coil assemblies to generate a maximum force.