Flexible Hinge Ring Compensates Friction Dead Zones in Galvo Motors
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Solution Overview
Problem
Galvo scanning motors face limitations in positioning precision due to frictional resistance changes during starting, stopping, and micro-rotation, causing 'crawling' and 'jitter' phenomena, which existing solutions like accurate friction force models and high-cost low-friction motion pairs fail to adequately address.
Innovation Solution
A rigid-flexible coupling high-accuracy galvo scanning motor design incorporating a rotating flexible hinge and friction bearing motion pair, with a flexible hinge ring made of aluminum alloy, compensates for friction dead zones through elastic deformation, and a closed-loop control system using encoders and an extended state observer for precise control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If friction bearing motion pair is used, then manufacturing cost is reduced, but positioning precision deteriorates due to frictional resistance changes
Solution Approach 1:
The patent introduces a flexible hinge ring that dynamically adapts to friction changes during motion. The flexible hinge allows the system to transition from a static rigid structure to a dynamic one that can compensate for frictional resistance variations, thereby maintaining positioning precision while using cost-effective friction bearings.
Solution Approach 2:
The patent changes the physical state of the hinge from rigid to flexible, allowing elastic deformation. This parameter change enables the hinge to absorb and compensate for friction-induced positioning errors, resolving the contradiction between using inexpensive friction bearings and maintaining high positioning precision.
2Manufacturing precision
If accurate friction force model is established, then positioning precision is improved through compensation control, but control complexity increases
Solution Approach 1:
The patent replaces the complex control system (software/algorithms for friction compensation) with a simple mechanical structure (flexible hinge ring). The flexible hinge passively compensates for friction effects through elastic deformation, eliminating the need for complex friction force modeling and compensation control algorithms.
Solution Approach 2:
The flexible hinge ring automatically compensates for positioning errors caused by friction without requiring external control intervention. The system self-adjusts through the elastic deformation of the hinge, making the control system simpler while maintaining high positioning precision.
3Manufacturing precision
If low-friction motion pair such as air bearing is used, then positioning precision is improved, but manufacturing cost increases significantly
Solution Approach 1:
The flexible hinge ring acts as an intermediary element between the friction bearing and the rotating shaft. It transmits motion while compensating for friction effects, enabling the system to achieve positioning precision comparable to low-friction bearings while using cost-effective friction bearings.
Solution Approach 2:
By changing the hinge from rigid to flexible, the system achieves low-friction performance characteristics without actually using low-friction motion pairs like air bearings. The elastic deformation of the flexible hinge creates a compliance that mimics the low-friction behavior, reducing manufacturing cost while maintaining precision.
4Manufacturing precision
If flexible hinge is used for continuous high-accuracy rotation, then positioning precision is improved, but elastic deformation range is limited causing nonlinearity and fatigue
Solution Approach 1:
The flexible hinge ring is designed to operate within a limited elastic deformation range, using only the necessary portion of its flexibility to compensate for friction effects. This partial action approach maintains positioning precision while avoiding excessive deformation that would cause nonlinearity and fatigue, thereby improving reliability.
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
This design achieves high-accuracy rotation and positioning precision by avoiding friction dead zones and estimating disturbing forces, reducing control complexity and enabling high-speed, frictionless motion without state switching, while being cost-effective and structurally simple.
Implementation Method 1
a flexible hinge ring which is elastically deformable
Data Source
AI summary
A rigid-flexible coupling high-accuracy galvo scanning motor comprises: a stator, a rotor rotating relative to the stator, bearing seats and at least two groups of encoders. The rigid-flexible coupling bearings are installed on the rotating shaft of the rotor; each of the rigid-flexible coupling bearings comprises: a rigid bearing and a flexible hinge ring which is elastically deformable, and the flexible hinge ring is fixed in an inner ring of the rigid bearing; the at least two groups of encoders comprise: a first group of encoders and a second group of encoders; the first group of encoders is used to measure a rotation angle of the rotating shaft; and the second group of encoders is used to measure a rotation angle of the inner ring of the rigid bearing. A friction dead zone is avoided through the elastic deformation of the flexible hinge ring, thereby reducing a disturbance bandwidth.