Magnetic Sensor Position Correction for Moving-Mirror Luminaire

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Solution Overview

Problem

Automated moving-mirror luminaires face challenges in detecting and correcting disturbances to the mirror's position, as existing systems lack lightweight sensors to report the mirror's current position accurately, leading to potential misalignment during transportation and installation.

Innovation Solution

Incorporating magnetic rotational sensors on both pan and tilt axis motors, which produce output signals representing the absolute rotational position, allowing the control system to determine if the mirror has been moved and take corrective action to restore its expected position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If lightweight sensors are added to detect mirror position, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvemirror position detection accuracyVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical position sensing systems with magnetic field-based sensors. Magnets are mounted on the mirror assembly, and magnetic sensors mounted on the luminaire body detect the mirror's pan and tilt positions through magnetic field interactions, eliminating the need for complex mechanical encoders or potentiometers.

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

Solution Approach 2:

The position detection system is segmented into independent pan-axis and tilt-axis sensing components. Each axis has its own dedicated magnets and sensors, allowing independent detection and correction of disturbances in each rotational degree of freedom without interfering with the other axis.

Inventive Principle:
Principle #1Segmentation

2Reliability

If the mirror is protected during transportation, then reliability is improved, but the ability to detect position disturbances worsens

Engineering Contradiction:
Improvemirror protection during handlingVSAvoidposition disturbance detection
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The magnetic sensors continuously monitor the mirror's actual position and provide feedback to the control system. The control system compares the sensed position with the expected position and automatically commands the motor to correct any deviations, ensuring the mirror returns to its precise intended position after any disturbance during handling or installation.

Inventive Principle:
Principle #23Feedback

3Speed

If the mirror is made lightweight for rapid movement, then speed is improved, but strength worsens

Engineering Contradiction:
Improvemirror movement speedVSAvoidmirror fragility
Core Design Contradiction:
SpeedVSStrength

Solution Approach 1:

The mirror assembly serves its own positioning needs through the integrated magnetic sensors mounted on the luminaire body that continuously track the mirror's position. This self-monitoring capability allows the lightweight mirror to automatically compensate for its own fragility issues by detecting and correcting position deviations without requiring additional structural reinforcement.

Inventive Principle:
Principle #25Self-service

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 enables accurate detection and correction of mirror position disturbances, ensuring precise alignment and minimizing the risk of misalignment during handling and installation, while maintaining the lightweight and rapid movement advantages of moving-mirror luminaires.

Implementation Method 1

The motion sensor system is configured to produce an output signal representing an absolute rotational position of the magnet

Methodology Applied
Scientific EffectMagnetic field sensing: Magnetic Field

Data Source

PatentEP3770494B1Disturbance sensing system for an automated moving-mirror luminaire
Publication Date: 2023.01.18 ROBE LIGHTING SRO
  • EP3770494B1 patent drawingFigure 1
  • EP3770494B1 patent drawingFigure 2
  • EP3770494B1 patent drawingFigure 3

AI summary

A luminaire (100) includes a mirror (112), a motion assembly (200), and a control system (600). The mirror (112) controllably deflects a light beam emitted from the luminaire (100). The motion assembly (200) includes a motor (208), a magnet (206) mounted directly to a shaft of the motor, and a motion sensor system (202). The motor (208) rotates the mirror (112) about an axis of rotation (201). Rotation of the motor causes an equal change in rotation of the mirror. The magnet's center aligns with the shaft's axis of rotation and the magnet's magnetic pole is oriented orthogonally to the shaft's axis of rotation. The motion sensor system produces an output signal representing an absolute rotational position of the magnet. The control system stores an expected rotational position of the motor and determines whether the motion sensor system's output signal matches the stored position. When the output signal does not match the stored position, the control system rotates the motor position where the output signal matches the stored position.