Vertical Actuator Gravity Compensation Reluctance Spring

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing vertical actuators face challenges in achieving precise positioning with minimal force transmission and vibration isolation, particularly in small working areas requiring micrometer-level accuracy, while also seeking a simpler and more efficient design.

Innovation Solution

A gravity-compensated vertical actuator design featuring a cone-shaped magnet yoke with a coil and a stationary cup-shaped magnet yoke, utilizing reluctance forces and a mechanical spring for counteracting weight, allowing for force-free displacement and precise positioning with minimal energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a vertical actuator uses reluctance forces between magnetic yokes to compensate gravity, then positioning accuracy is improved, but electrical losses and heat input increase

Engineering Contradiction:
Improvepositioning accuracyVSAvoidelectrical losses
Core Design Contradiction:
Measurement precisionVSLoss of energy

Solution Approach 1:

The patent applies the anti-weight principle by using a mechanical spring to counterbalance the gravitational force on the movable structural unit. The spring is pre-loaded to exert an upward force that compensates for the weight, allowing the unit to be held in position without continuous electrical power. This eliminates the need for continuous reluctance force generation, thereby reducing electrical losses and heat input while maintaining positioning accuracy.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The patent implements periodic action by using pulse-width modulation (PWM) to control the coil current. Instead of continuous current flow, the coil is energized in periodic pulses to generate reluctance forces only when needed for positioning adjustments. This reduces average electrical losses and heat generation while maintaining the ability to achieve micrometer-level positioning accuracy through controlled periodic actuation.

Inventive Principle:
Principle #19Periodic action

2Object-affected harmful factors

If a vertical actuator uses a mechanical spring and magnetic spring combination, then vibration transmission is reduced, but device complexity increases

Engineering Contradiction:
Improvevibration transmissionVSAvoidstructure complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent merges the mechanical spring and magnetic spring functions into a unified gravity compensation system. The mechanical spring provides the primary counterbalance to gravity, while the magnetic field system provides fine adjustment and positioning control. This combination achieves vibration isolation by distributing the support function between elastic and magnetic elements, reducing the transmission of mechanical vibrations to the movable structural unit while maintaining a relatively simple overall structure through functional integration.

Inventive Principle:
Principle #5Merging (Combining)

3Area of stationary object

If the working area is reduced to a few millimeters, then space efficiency is improved, but positioning accuracy requirements increase to micrometer range

Engineering Contradiction:
Improveworking areaVSAvoidpositioning accuracy
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

The patent applies parameter changes by utilizing the non-linear relationship between the air gap distance and reluctance force. By carefully designing the magnetic circuit geometry and controlling the air gap variations within the small working area, the system achieves high positioning sensitivity. The reluctance force changes dramatically with small air gap changes, enabling micrometer-level positioning control within a millimeter-scale working area through precise parameter control rather than increased system complexity.

Inventive Principle:
Principle #35Parameter changes

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 precise positioning with reduced electrical losses and heat input, self-returning mechanism, and optimized vibration isolation, achieving linear dependency of reluctance force on Z-position with minimal current requirements.

Implementation Method 1

a reluctance force (R) acts between the first and second structural unit, which counteracts the weight (G) of the movable structural units

Methodology Applied
Scientific EffectMagnetic reluctance: Magnetic Reluctance

Implementation Method 2

the movable of the two structural units is connected to a stationary area via a mechanical spring, which exerts a spring force (F) on the movable of the two structural units

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 3

a reluctance force (R) acts between the first and second structural unit

Methodology Applied
Scientific EffectMagnetic attraction: Magnetism

Data Source

PatentEP2501023B1Vertical actuator with gravity compensation
Publication Date: 2021.01.27 ETEL SA
  • EP2501023B1 patent drawingFigure 1
  • EP2501023B1 patent drawingFigure 2
  • EP2501023B1 patent drawingFigure 3

AI summary

The drive has a fixed subassembly (2) and a movable subassembly (1) moved in a vertical direction (Z). The movable subassembly has a magnetic yoke (3) with a coil (4). The fixed subassembly has another magnetic yoke (5) with a magnet (6) aligned to the coil. A horizontal gap between the magnetic yokes in a region of the magnet is varied in the vertical direction such that reluctance force (R) between the subassemblies acts in a working area of the drive. The reluctance force counteracts weight force (G) of the subassemblies.