Piezoelectric Driving Device Intermittent Signal Control
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Solution Overview
Problem
In piezoelectric driving devices, intermittent driving signals lead to inaccuracies in feedback control due to unintended voltage amplitudes generated during the OFF period, affecting the accuracy of the driving signal and the target driving performance.
Innovation Solution
A control method that detects only the output period voltage amplitude in the driving signal and generates a target pulse duty ratio based on this, while ignoring the suspension period voltage amplitude, to prevent inaccuracies and maintain stable driving performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If intermittent driving signal is used to reduce driving speed, then driving speed is reduced, but measurement precision of voltage amplitude deteriorates due to detection of unintended voltage during OFF time
Solution Approach 1:
The invention extracts only the useful voltage amplitude information from the intermittent driving signal by detecting voltage amplitude exclusively during the ON time periods and excluding voltage amplitudes detected during OFF time periods. This separation allows accurate measurement of driving signal characteristics while maintaining the speed-reducing benefit of intermittent operation.
Solution Approach 2:
The invention performs preliminary classification of detection timing by establishing that voltage amplitude detection occurs only during predetermined ON time periods before feedback control is executed. This preliminary action prevents contamination of measurement data with unintended voltage amplitudes that would otherwise be detected during OFF periods.
2Reliability
If feedback control is performed on intermittent driving signal, then driving signal accuracy can be improved, but unintended voltage amplitude is detected during OFF time causing deterioration of control accuracy
Solution Approach 1:
The invention extracts only the relevant voltage amplitude data for feedback control by detecting and utilizing exclusively the voltage amplitude during ON time periods. This extraction process eliminates the harmful influence of unintended voltage amplitudes detected during OFF periods, thereby maintaining both reliability and measurement precision in the feedback control system.
Solution Approach 2:
The invention implements feedback control using only the voltage amplitude detected during ON time periods as the feedback parameter. By restricting feedback to this specific time window, the system achieves accurate control while avoiding the degradation caused by OFF-time voltage amplitudes that do not reflect actual driving signal characteristics.
3Loss of information
If voltage amplitude is detected during both ON and OFF periods, then complete voltage information is obtained, but accuracy of driving signal control deteriorates due to inclusion of unintended voltage amplitude
Solution Approach 1:
The invention applies local quality by treating voltage detection differently depending on the time period: during ON periods, voltage amplitude is detected and used for control, while during OFF periods, voltage amplitude is not detected and excluded from control. This localized approach ensures that only meaningful voltage information contributes to driving signal accuracy.
Solution Approach 2:
The invention extracts and utilizes only the useful portion of voltage information (during ON periods) while deliberately excluding the harmful portion (during OFF periods). This selective extraction maintains driving signal accuracy by ensuring that feedback control is based solely on voltage amplitudes that reflect actual driving conditions.
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 approach reduces the apparent amplitude of the driving signal, allowing for stable operation at low speeds and accurate control of the piezoelectric elements, thereby enhancing the driving characteristics of the piezoelectric motor.
Implementation Method 1
an ultrasonic motor including a piezoelectric element that extends and contracts according to application of a voltage
Implementation Method 2
electric charges involved in a piezoelectric effect are generated in the piezoelectric element
Data Source
AI summary
There is provided a control method for a piezoelectric driving device including a vibrating body configured to vibrate when a driving signal including a periodic signal is applied to a piezoelectric element for driving, a section to be driven that is driven by the vibration of the vibrating body, and a driving-signal generating section configured to generate the driving signal using a pulse signal generated based on a target pulse duty ratio. The driving-signal generating section detects voltage amplitude generated in the piezoelectric element for driving and generates the target pulse duty ratio based on the voltage amplitude. The driving signal includes an intermittent signal formed by an output period in which the periodic signal is output and a suspension period in which the output of the periodic signal is suspended. The driving-signal generating section detects the output-period voltage amplitude and does not detect the suspension-period voltage amplitude.