Piezoelectric Displacement Sensor Voltage Reset Control
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Solution Overview
Problem
Piezoelectric sensors fail to accurately detect displacement as they reset to initial voltage when bent, leading to inaccurate voltage readings for subsequent displacements.
Innovation Solution
A displacement detection device with a piezoelectric sensor and control means that short-circuits or opens detection electrodes to measure and integrate voltage changes, allowing for accurate calculation of displacement by resetting the voltage at predetermined intervals and using a capacitor to extend output voltage measurement time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a piezoelectric sensor is used to detect displacement, then voltage is generated in accordance with bending amount, but the voltage turns back to the original state when the bending state is held constant, leading to inaccurate displacement detection
Solution Approach 1:
The control means performs preliminary action by resetting the piezoelectric sensor's voltage to the reference state at predetermined intervals using the switch, before the voltage naturally decays. This proactive resetting ensures that each subsequent displacement measurement starts from a known baseline, preventing accumulation errors and maintaining measurement accuracy over time.
Solution Approach 2:
The control means implements periodic action by repeatedly resetting the piezoelectric sensor's voltage at predetermined time intervals. This periodic resetting creates a cyclical pattern where the sensor is consistently returned to its reference state, enabling accurate detection of displacement changes from a known baseline in each measurement cycle.
2Measurement precision
If the piezoelectric sensor voltage is continuously measured, then displacement can be detected, but power consumption increases
Solution Approach 1:
The control means applies periodic action by measuring and resetting the piezoelectric sensor's voltage only at predetermined intervals rather than continuously. This time-discretized approach maintains displacement detection capability while significantly reducing power consumption by keeping the measurement and control circuits inactive during intervals between measurements.
Solution Approach 2:
The control means extracts only the essential measurement moments by selectively activating the voltage measurement and reset operations at predetermined intervals. Instead of maintaining continuous measurement functionality, the system extracts and processes only the necessary data points, reducing energy consumption while preserving displacement detection accuracy.
3Measurement precision
If the piezoelectric sensor output voltage measurement time is extended, then more accurate integration can be performed, but the voltage naturally decays over time
Solution Approach 1:
The control means performs preliminary action by resetting the piezoelectric sensor's voltage to the reference state at predetermined intervals, before the voltage decay significantly affects measurement accuracy. This proactive intervention extends the effective measurement window by continuously replenishing the voltage, allowing for more accurate integration over longer periods.
Solution Approach 2:
The control means maintains continuity of useful action by repeatedly resetting the piezoelectric sensor's voltage at predetermined intervals. This continuous replenishment of voltage ensures that the sensor maintains its output capability throughout extended measurement periods, enabling accurate integration without being limited by natural voltage decay.
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 detection of displacement by ensuring measured voltage changes reflect actual displacement amounts, reducing power consumption and improving sensitivity through the use of polylactic acid and specific electrode configurations.
Implementation Method 1
The piezoelectric substance used in such a piezoelectric sensor generates a voltage in accordance with an amount of bending at the moment of application of bending stress
Implementation Method 2
a capacitor connected in parallel to the piezoelectric sensor... by providing the capacitor, an attenuation time constant of the output voltage of the piezoelectric sensor decreases, and time for holding the output voltage becomes longer
Data Source
AI summary
A displacement detection device includes a piezoelectric sensor. The piezoelectric sensor is provided with a piezoelectric sheet on both principal surfaces of which detection electrodes are formed. When stress is applied to the piezoelectric sensor, charge is generated, and an output voltage in accordance with this generated charge is detected in a DC voltage detector. A controller measures this output voltage at a predetermined time interval. Every time the controller measures the output voltage, the controller makes a short-circuit control of a switch, and causes the charge generated in the piezoelectric sensor to be released. The controller can thereby detect an amount of change in output voltage generated at the predetermined time interval in accordance with an amount of displacement of the piezoelectric sensor. By sequentially integrating this, the controller can accurately detect the amount of displacement of the piezoelectric sensor which changes across measurement timings.