Piezo Drive Pulse Control for Nonlinear Positioning Accuracy
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Solution Overview
Problem
Existing piezoelectric driving devices face challenges in controlling the position of passive elements relative to active elements due to nonlinear characteristics, necessitating improved positional control methods and controllers.
Innovation Solution
A driving-unit operation method and controller that modify drive signals based on position error signals, adjusting pulse shape or excitation frequency and pulse block duty cycle to achieve precise positional control, using a controller connected to excitation sections and sensors for position judgment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional drive signals are used to drive piezoelectric elements, then the driving device can operate, but positional control precision deteriorates due to nonlinear characteristics
Solution Approach 1:
The drive signal is made dynamic by repeatedly omitting drive pulses to create pulse blocks with variable duty cycles. This dynamic signal adaptation allows the system to compensate for nonlinear characteristics of the piezoelectric elements, achieving precise positional control that conventional static drive signals cannot provide
Solution Approach 2:
The invention changes key parameters of the drive signal including pulse width, pulse block duty cycle, and excitation frequency. By modifying these parameters based on position error feedback, the system adapts to nonlinear characteristics and achieves accurate positional control of the passive element
2Measurement precision
If drive pulses are continuously applied, then the passive element moves continuously, but positional control accuracy deteriorates due to nonlinear vibration characteristics
Solution Approach 1:
The invention applies periodic action by creating pulse blocks with repeated omitted drive pulses. This periodic modulation of the drive signal allows the system to control the average movement speed while maintaining positional accuracy, overcoming the limitations of continuous drive pulses that cause nonlinear vibration effects
3Measurement precision
If simple drive signals are used, then the device complexity is low, but the ability to control position under nonlinear conditions deteriorates
Solution Approach 1:
The system employs feedback by measuring the actual position of the passive element and comparing it with the target position. Based on the position error signal, the controller dynamically adjusts the pulse block duty cycle and drive pulse characteristics, enabling accurate positional control without requiring complex hardware modifications
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 accurate and efficient positional control of passive elements relative to active elements, enhancing the performance of devices like camera modules by reducing image blurring and vibration, particularly in smartphone cameras with AF and OIS functions.
Implementation Method 1
at least one excitation section configured to excite a vibration of the resonator
Implementation Method 2
the resonator including at least one arm extending from a coupling portion of the resonator, the at least one arm including a contact portion at an outer end of the at least one arm, the contact portion being movable by vibrational motion
Data Source
AI summary
A driving-unit operation method includes: generating pulse blocks on the basis of driving pulses; and modifying a driving signal in accordance with a position error signal. In the modifying the driving signal, when the position error signal is in a first range, the shape of the driving pulses is modified so as to form a first driving-pulse shape, and the pulse-block duty cycle is set to a first pulse-block duty cycle value, whereas when the position error signal is in a second range, the shape of the driving pulses is modified so as to form a second driving-pulse shape, and the pulse-block duty cycle is set to a second pulse-block duty cycle value.