Piezoelectric Transmission Systems for Precision Motion Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing transmission systems for piezoelectric motors face challenges in accurately and rapidly controlling the motion and positioning of small, delicate components in mechanical, opto-mechanical, and electromechanical systems, particularly in constrained spaces such as those found in modern cell phones, where size and precision requirements are increasingly stringent.
Innovation Solution
The development of coupled double-pendulum, rail-rider, and pendulum transmission systems that utilize piezoelectric motors to transmit kinetic energy efficiently, with mechanisms such as resiliently coupled motion bars, drive-rails, and rotatable pendulums to enable precise and directional movement of moveable bodies, while minimizing perpendicular motion and ensuring low friction connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional piezoelectric motors are used to move and position components, then kinetic energy can be transmitted to the moveable body, but the system size becomes large and precision requirements become difficult to meet in constrained spaces
Solution Approach 1:
The transmission system is divided into multiple functional segments: piezoelectric motor, resilient element, motion bar, and moveable body. This segmentation allows each component to be optimized independently for precision while keeping individual component sizes small, resolving the contradiction between positioning accuracy and system size.
Solution Approach 2:
The piezoelectric motor is mounted within a housing that contains the resilient element, which in turn connects to the motion bar and moveable body. This nested arrangement consolidates multiple components into a compact configuration, achieving high positioning precision without increasing overall system volume.
2Productivity
If the piezoelectric motor is directly coupled to the moveable body, then kinetic energy transmission is direct, but friction and mechanical binding increase reducing accuracy and speed
Solution Approach 1:
A resilient element is introduced as an intermediary between the piezoelectric motor and the motion bar. This mediator transmits kinetic energy while accommodating minor misalignments and reducing friction, thereby improving both movement speed and positioning accuracy simultaneously.
Solution Approach 2:
The resilient element provides dynamic coupling that allows the system to adapt to varying load conditions and motion requirements. This dynamic connection maintains low friction during movement while preserving positioning accuracy, resolving the contradiction between productivity and reliability.
3Measurement precision
If transmission mechanisms are added to improve positioning accuracy, then motion control precision increases, but device complexity increases
Solution Approach 1:
Complex multi-stage gear transmissions are extracted and replaced with a simplified direct-drive configuration using a motion bar and resilient element. This extraction maintains high motion control precision while significantly reducing device complexity.
Solution Approach 2:
Traditional mechanical transmission components (gears, belts, linkages) are replaced with a piezoelectric motor that directly generates motion through vibrational modes. This substitution achieves high precision motion control with minimal mechanical complexity.
4Productivity
If the system is designed for rapid movement, then productivity increases, but positioning accuracy and control precision deteriorate
Solution Approach 1:
The piezoelectric motor operates in periodic vibrational modes to generate motion. By controlling the frequency and amplitude of these periodic vibrations, the system achieves rapid movement while maintaining precise positioning control through feedback on the vibrational characteristics.
Solution Approach 2:
The system dynamically adjusts operational parameters (vibration frequency, amplitude, and duration) to optimize both movement speed and positioning accuracy. By changing these parameters based on the specific task requirements, the system resolves the contradiction between productivity and measurement precision.
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
These transmission systems effectively enable precise, rapid, and accurate movement and positioning of components by leveraging piezoelectric motors to generate controlled vibrations, thereby addressing the size and precision constraints in modern applications like cell phone cameras, with reduced backlash and improved accuracy.
Implementation Method 1
A piezoelectric motor, optionally similar to a motor described in U.S. Pat. No. 5,616,980 referenced above, is coupled to the motion bar. Vibrations generated in the piezoelectric motor apply force to the motion bar to move the bar selectively along either direction parallel to the bar's length.
Data Source
AI summary
Apparatus for transmitting motion to a moveable body comprising: a first bar having ends; two articulated arms, each comprising first and second arms connected at a joint having an axis about which the first and second arms rotate, wherein the first arms are of equal length, the second arms are of equal length and the second arm of each articulated arm is connected to a different end of the bar at a joint having an axis about which second arm and bar rotate; a mount connected to the first arm of each articulated arm at a joint having an axis about which first arm rotates; a second bar coupled to each articulated arm at a joint having an axis about which the second bar rotates; and a piezoelectric motor coupled to the first bar controllable to apply a force selectively in either direction along the bar's length; wherein, the joints are configured so that all the axes are substantially parallel and the first arms are parallel and the second arms are parallel for all rotations about the axes.