Piezoelectric Actuator Drive Device Discharge Control
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Solution Overview
Problem
Conventional piezoelectric actuator drive devices struggle to control the discharging energy rate at a constant value, especially when the capacitance of the piezoelectric actuators changes due to temperature variations, leading to fluctuations in energy discharging rates.
Innovation Solution
A piezoelectric actuator drive device with a threshold value setting mechanism that adjusts the peak threshold value in proportion to time, using detected electric charge values to set a gradient and intercept, allowing for precise control of the discharging energy rate by dynamically changing the discharging energy and period, ensuring a constant discharging energy rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the peak threshold value is increased to maintain discharging energy, then the discharging energy can be maintained, but the discharging period becomes unstable and fluctuates
Solution Approach 1:
The patent applies dynamics by making the peak threshold value dynamic rather than static. The control device adjusts the peak threshold value in real-time based on the actual discharging period measurement. When the discharging period deviates from the target value, the control device modifies the peak threshold value to compensate, thereby maintaining both stable discharging energy and consistent discharging period.
Solution Approach 2:
The patent implements feedback control by continuously measuring the actual discharging period and using this information to adjust the peak threshold value. The control device compares the measured discharging period against the target period and modifies the threshold accordingly, creating a closed-loop control system that stabilizes both energy discharge and timing.
2Use of energy by moving object
If the peak threshold value is increased to compensate for capacitance changes, then the discharging energy can be maintained, but the control precision deteriorates
Solution Approach 1:
The patent uses feedback control to maintain precision by continuously measuring the actual discharging period and adjusting the peak threshold value accordingly. This closed-loop approach allows the system to compensate for capacitance changes while maintaining accurate control, as adjustments are made based on actual measurements rather than rough estimations.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the peak threshold value based on measured discharging period and detected capacitance values. Rather than using a fixed threshold, the system modifies this critical parameter in real-time to maintain both energy levels and control precision despite varying operating conditions.
3Device complexity
If a fixed peak threshold value is used, then the device complexity is reduced, but the adaptability to capacitance changes deteriorates
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed threshold system to a dynamic adjustment system. The control device automatically modifies the peak threshold value based on real-time measurements of discharging period and capacitance detection, enabling the system to adapt to capacitance changes without requiring complex manual intervention or overly complicated control mechanisms.
Solution Approach 2:
The patent implements self-service by enabling the control device to automatically adjust its own operating parameters. The system detects capacitance changes and discharging period variations, then autonomously modifies the peak threshold value to maintain optimal performance, eliminating the need for external calibration or complex adaptive 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
This approach enables efficient adjustment of the discharging energy rate to a target constant value, even with changes in capacitance, stabilizing the energy discharge and allowing for accurate control of the remaining energy in the piezoelectric actuators.
Implementation Method 1
Piezoelectric actuators are well known and widely used in various types of devices. In general, a piezoelectric actuator expands and contracts by electrical charging and discharging in order to control a linear motion of a piston.
Implementation Method 2
A DC power source supplies an electric power to a series circuit composed of an inductor and the piezoelectric actuator through the charging path and a charging switch. After this, by turning the charging switch OFF, a charging current (namely, a fly wheel current), which flows by the electrical energy charged in the inductor, is supplied to the piezoelectric actuator
Data Source
AI summary
In a piezoelectric actuator control device for controlling operation of one or more piezoelectric actuators, when receiving a drive signal of a low level, a discharging switch is repeatedly turned on and off in order to discharge electric charge accumulated in the piezoelectric actuator. That is, the discharging switch is kept ON until a discharging current from a piezoelectric actuator reaches a peak threshold value Ip. When the discharging current reaches the peak threshold value Ip, the discharging switch is turned OFF and kept OFF until a discharging current from a piezoelectric actuator reaches a peak threshold value Ip. The device has a threshold value setting circuit for increasing the peak threshold value according to a discharging period of time.