Piezoelectric Actuator Hysteresis Compensation via Segmented Voltage Control
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Solution Overview
Problem
Piezoelectric actuators suffer from hysteresis, which degrades their linearity characteristic, making it difficult to control displacement with high precision due to the lack of effective feedback control and the inability to independently control the piezoelectric plates used in bimorph actuators.
Innovation Solution
A piezoelectric driving device and method that includes a laminated body with a base, first and second piezoelectric bodies, a driving voltage generator, a compensating voltage generator, and a voltage applicator, allowing for independent voltage application to each piezoelectric body to compensate for hysteresis and improve linearity by generating compensating voltages based on displacement measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a bimorph actuator with one piezoelectric plate as sensor and one as driver is used, then hysteresis can be corrected through feedback control, but the displacement control precision is still limited due to the inability to independently control both piezoelectric plates
Solution Approach 1:
The actuator is divided into two independently controllable piezoelectric plates (first and second piezoelectric bodies) laminated on opposite faces of a base. This segmentation allows independent voltage application to each plate, enabling separate control of expansion and contraction forces to achieve higher displacement precision while compensating for hysteresis effects
Solution Approach 2:
The invention changes the control parameter from single-voltage feedback control to dual-voltage independent control. By applying different voltages to the first and second piezoelectric bodies based on their respective piezoelectric coefficients, the system can precisely control displacement while compensating for hysteresis without requiring complex feedback circuits
2Ease of operation
If voltage is applied to piezoelectric actuators to achieve displacement control, then the actuator can be driven, but hysteresis degrades linearity characteristic making precise control difficult
Solution Approach 1:
By segmenting the actuator into two independently controllable piezoelectric bodies with different piezoelectric coefficients, the system can apply tailored voltages to each segment to maintain linear displacement control while compensating for hysteresis effects that would otherwise degrade linearity
Solution Approach 2:
The invention uses a composite structure with two different piezoelectric bodies having different piezoelectric coefficients laminated on opposite faces of the base. This composite configuration enables the system to exploit the different material properties to achieve both ease of operation and high linearity by independently controlling the contribution of each material layer
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 solution enables precise control of displacement with reduced hysteresis, improving the linearity of the piezoelectric actuator by applying compensating voltages to the second piezoelectric body, allowing for accurate displacement control without complex feedback circuits.
Implementation Method 1
a first piezoelectric body 130 and a second piezoelectric body 140 which are different from each other in piezoelectric coefficients, are formed on first and second faces 122, 124 of the base 120
Implementation Method 2
A piezoelectric actuator has hysteresis between an applied voltage and a displacement amount in accordance with increase and decrease directions of the applied voltage
Data Source
AI summary
A piezoelectric driving device including a laminated body having a base that is capable of being deformed by applying force, a first piezoelectric body that is formed on a first face of the base directly or via another layer, and a second piezoelectric body that is formed on a second face of the base substantially parallel to the first face directly or via another layer, a driving voltage generating section that generates a driving voltage according to a displacement amount of the laminated body, a compensating voltage generating section that generates a compensating voltage compensating for hysteresis caused by the displacement of the laminated body by the driving voltage, and a voltage applying section that applies each of the driving voltage and the compensating voltage to each of the first piezoelectric body and the second piezoelectric body.