Quartz Force Sensor Thermal Noise Reduction
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Solution Overview
Problem
Force detecting devices in industrial robots using quartz piezoelectric elements are prone to noise due to heat-generated deformation, which affects the accuracy of force measurements during machining processes.
Innovation Solution
A force detecting device with charge output elements, including piezoelectric sensors arranged in a configuration that allows for the detection of forces along three orthogonal axes, where the sensors are inclined to minimize the impact of temperature-induced noise, and a circuit system that converts charges into voltages to accurately detect external forces without relying on temperature-sensitive measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If quartz piezoelectric elements are used for force detection during machining, then force measurement capability is achieved, but temperature-induced deformation causes noise that reduces measurement accuracy
Solution Approach 1:
The patent converts the harmful temperature-induced deformation into a beneficial signal by strategically placing piezoelectric elements on both the hot and cold sides of the heat source. The deformation from temperature changes is transformed into useful charge signals that can be processed to extract accurate force measurement information, thereby converting the harmful thermal effect into a useful measurement mechanism.
Solution Approach 2:
The patent transitions from single-sided force detection to multi-dimensional detection by placing piezoelectric elements on both the hot side and cold side of the heat source. This spatial arrangement in multiple dimensions allows the system to distinguish between thermal deformation effects and actual force signals, enabling accurate force measurement despite temperature fluctuations.
2Adaptability or versatility
If multiple piezoelectric elements are arranged to detect forces along three orthogonal axes, then comprehensive force detection capability is achieved, but device complexity increases
Solution Approach 1:
The patent achieves multi-functionality by having piezoelectric elements serve dual purposes: they detect both thermal deformation effects and mechanical force signals. The same elements that would normally require separate thermal compensation mechanisms instead directly contribute to force measurement by capturing signals from both temperature-induced deformation and applied forces along three orthogonal axes.
Solution Approach 2:
The patent merges the thermal compensation function with the force detection function into a unified system. Instead of using separate sensors for thermal monitoring and force measurement, the piezoelectric elements perform both functions simultaneously, reducing device complexity while maintaining comprehensive detection capability along three axes.
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 device provides stable and accurate force detection, reducing temperature-induced noise to 1/20 of previous levels, enabling precise force measurement even in environments with significant temperature fluctuations, and reducing the overall weight and size of the force detecting system.
Implementation Method 1
a first sensor device (6A) including a charge output element (10) which outputs a signal according to an applied external force
Implementation Method 2
the quartz is deformed by heat generated during the machining. As a result, a noise component with respect to a true value in an output of the piezoelectric element tends to occur
Data Source
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AI summary
A force detecting device (1) includes a first base section (2), a second base section, and a charge output element arranged between the first base section (2) and the second base section. The charge output element includes a first board formed by a Y-cut quartz plate and a second board formed by a Y-cut quartz plate. The boards are laminated in a direction orthogonal to the normal an attachment surface of the second base section. The force detecting device (1) detects an external force on the basis of a first output corresponding to a shearing force in a first detection direction orthogonal to the laminating direction of the first board and a second output corresponding to a shearing force in a second detection direction orthogonal to the laminating direction of the second board and crossing the first detection direction.