Multi-Beam 3D Scanner Voice Coil Actuator Stability

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Solution Overview

Problem

Current 3D scanning technologies face challenges with directional accuracy and positional inaccuracy, particularly in rotary systems, leading to alignment errors and wobble issues, especially at high rotation speeds, which affect the precision of measured data.

Innovation Solution

A measuring device with a rotating member and a longitudinal member, featuring a transmission unit, a receiver unit, and an angle determining unit, utilizing angular contact ball bearings and a motor with magnetic elements for precise rotation, and an angular processing unit for accurate angle interpolation and extrapolation, ensuring high stiffness and low friction to minimize hysteresis and wobble errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If rotary axes are used for 3D scanning, then scanning coverage and measurement speed are improved, but directional accuracy and positional precision deteriorate due to wobble and hysteresis errors

Engineering Contradiction:

Improvescanning speedVSAvoiddirectional accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent replaces the traditional mechanical rotary axis with a voice coil actuator that uses electromagnetic force to position the transmission unit. This substitution eliminates mechanical friction, backlash, and wobble inherent in rotary bearings, achieving both high scanning speed and high directional accuracy through precise electromagnetic control of the transmission beam angles.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The transmission unit is designed to perform multiple functions: it acts as both the mounting structure for the laser transmitter and the positioning mechanism for the transmission beam. By integrating the beam directing function into the transmission unit itself, the system achieves high positional accuracy without requiring separate positioning mechanisms that would add complexity and potential error sources.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Productivity

If rotation speed is increased beyond 50 or 100 Hz, then measurement productivity is improved, but wobble and hysteresis errors increase, reducing measurement precision

Engineering Contradiction:

Improvemeasurement speedVSAvoidalignment accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The voice coil actuator provides contactless electromagnetic positioning, eliminating the mechanical friction and inertia that cause wobble and hysteresis in traditional rotary systems. This allows the system to achieve high measurement speeds with maintained precision, as the electromagnetic force can respond instantaneously without mechanical lag or vibration.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If conventional bearing arrangements are used, then device complexity is reduced, but directional accuracy deteriorates due to alignment errors in transmission beams

Engineering Contradiction:

Improvebearing arrangement simplicityVSAvoidbeam alignment accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent extracts the positioning function from the bearing arrangement and relocates it to the voice coil actuator. This separation allows the bearing to focus solely on supporting the rotating mass, while the voice coil provides precise angular positioning of the transmission unit, eliminating the compromise between bearing simplicity and alignment accuracy.

Inventive Principle:

Principle #2Taking out (Extraction)

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 achieves high directional accuracy and precise 3D scanning with reduced hysteresis and wobble errors, enabling repeated measurements with high precision and accuracy, even at high rotation speeds, and supports applications in navigational and mapping purposes on mobile platforms.

Implementation Method 1

a voice coil actuator for generating an electromagnetic force for positioning the transmission unit

Methodology Applied

Scientific EffectElectromagnetic force: Lorentz Force

Implementation Method 2

featuring a transmission unit, a receiver unit, and an angle determining unit, utilizing angular contact ball bearings

Methodology Applied

Scientific EffectBall bearing: Ball Bearing

Data Source

PatentEP3822657B1Multi-beam measuring device with high directional stability for 3D scanning of an environment

Publication Date: 2024.02.21 HEXAGON TECH CENT GMBH

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AI summary

The inventive measuring device (1) comprises a base (4), a case (5) and a rotating member (6) rotatable about the axis of rotation (3). The rotating member (6) comprises a transmission unit (7) configured to emit transmission beams (2) to different beam directions. The rotating member (6) further comprises a receiver unit (9) configured to receive returning transmission beams (2). A longitudinal member (11) is fixed to the base (4) and extends in a central area of the rotating member (6) along the axis of rotation (3) over a range including the transmission unit (7) and the receiver unit (9). Two bearing members (12) are arranged on the longitudinal member (11) and on the rotating member (6). In the direction of the axis of rotation (3), the transmission unit (7) and the receiver unit (9) are located in a range between the two bearing members (12). The measuring device (1) has a high aiming accuracy and low hysteresis of the turning transmission beams (2).