Piezo Ceramic Planar Motor with Levitation for High-Speed Nano-Positioning
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Solution Overview
Problem
Conventional nano-positioning platforms face limitations in movement range and speed, with electromagnetic motors requiring complex control, ultrasonic motors needing expensive materials, piezo walking platforms being slow, and piezo stick-slip platforms experiencing abrasion and low driving force.
Innovation Solution
A piezo-actuated planar motor with piezo ceramic driving legs, levitation devices, and preload mechanisms, enabling omnidirectional movement and multiple motion control modes (sliding, walking, and fine tuning) for high accuracy and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If electromagnetic planar motor is used, then driving force is sufficient, but motion control becomes complex
Solution Approach 1:
The patent replaces the electromagnetic driving system with a piezoelectric ceramic driving system. The piezoelectric ceramic driving leg converts electrical signals directly into mechanical displacement through the piezoelectric effect, eliminating the need for complex electromagnetic motion control while providing sufficient driving force for the nano-positioning platform.
Solution Approach 2:
The patent divides the driving function into multiple piezoelectric ceramic driving legs (typically three or more) arranged around the mover. Each driving leg independently provides driving force in a specific direction, and their coordinated operation achieves omnidirectional motion control with simpler individual control logic compared to electromagnetic systems.
2Measurement precision
If ultrasonic motor is used, then positioning accuracy is high, but friction materials become expensive
Solution Approach 1:
The patent replaces the ultrasonic motor's friction-based drive mechanism with a piezoelectric ceramic driving mechanism. The piezoelectric ceramic driving leg directly converts electrical energy to mechanical displacement without relying on friction materials, thereby maintaining high positioning accuracy while eliminating the need for expensive friction materials.
3Measurement precision
If piezo walking platform is used, then positioning accuracy is high, but movement speed becomes slow
Solution Approach 1:
The patent employs periodic driving signals applied to the piezoelectric ceramic driving leg to generate controlled oscillatory motion. By adjusting the frequency and amplitude of these periodic signals, the system achieves both high positioning accuracy through precise control and improved movement speed through optimized oscillation parameters, overcoming the speed limitation of conventional piezo walking platforms.
Solution Approach 2:
The patent introduces dynamic control mechanisms where the driving parameters of the piezoelectric ceramic driving leg are continuously adjusted based on real-time positioning requirements. This dynamic adjustment allows the system to switch between high-precision slow positioning and faster movement modes, resolving the contradiction between positioning accuracy and movement speed.
4Length of moving object
If piezo stick-slip platform is used, then movement range is small, but driving force is insufficient and abrasion occurs
Solution Approach 1:
The patent extracts the mover from direct contact with the planar substrate by introducing a levitation device. This separation eliminates the sliding friction and associated abrasion problems of stick-slip platforms while allowing the piezoelectric ceramic driving leg to generate sufficient driving force without being constrained by friction limitations, thereby enabling both larger travel range and adequate driving force.
Solution Approach 2:
The patent introduces a levitation device as an intermediary between the piezoelectric ceramic driving leg and the planar substrate. This intermediary eliminates direct mechanical contact and friction, allowing the driving leg to operate with sufficient driving force over an extended travel range without experiencing the abrasion and force limitations of direct contact stick-slip mechanisms.
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 piezo-actuated planar motor achieves high positioning accuracy, large travel range, and fast motion speeds with reduced abrasion, offering a stable and precise nano-positioning solution suitable for semiconductor manufacturing and micro/nano processing.
Implementation Method 1
at least one piezo ceramic driving leg which is disposed on said mover so as to drive said mover to move on said planar substrate omnidirectionally in the plane
Implementation Method 2
said levitation device is a magnetic levitation device or an air levitation device
Implementation Method 3
said air levitation device is at least one air bearing
Implementation Method 4
said preload mechanism is a vacuum preload mechanism
Implementation Method 5
said preload mechanism is a vacuum preload mechanism or a magnetic-force preload mechanism
Data Source
AI summary
Provided is a piezo-actuated planar motor, comprising a planar substrate and a mover installed on the planar substrate, the piezo-actuated planar motor further comprising: at least one piezo driving leg which is disposed on said mover so as to drive said mover to move on said planar substrate omnidirectionally in the plane. Further provided is a method of driving a planar motor by using piezo driving legs, which implements three movement modes, i.e., a sliding mode, a walking mode, and a fine tuning mode. The sliding mode has the fastest speed of motion, the walking mode has a relatively slow speed of motion but has a high positioning accuracy and a high-accuracy tracking capability, and the fine tuning mode is used for the adjustment of the planar motor at a final position and has the highest positioning accuracy. The piezo-actuated planar motor of the present invention can effectively overcome the defects of a small movement range and a low speed in a conventional nano-positioning platform.