Load Frame Assembly with Capacitive Displacement Sensor
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing load frame systems face challenges in accurately controlling micro and nano movements and small loads during materials testing, especially when analyzing small samples under a microscope, due to minor losses and equipment tolerances affecting test results.
Innovation Solution
A load frame assembly comprising a servomotor, actuator assembly, crosshead assemblies, and displacement sensors, with a control system that includes a ball screw assembly and capacitive sensors for precise linear movement and displacement measurement, minimizing equipment effects and enhancing control over micro and nano movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional load frame systems are used for materials testing, then basic testing functionality is provided, but control accuracy over micro and nano movements and measurement precision deteriorate due to equipment tolerances and minor losses
Solution Approach 1:
The patent replaces conventional mechanical measurement systems with capacitive sensors that use electrical fields to measure displacement. This substitution eliminates mechanical contact and associated tolerances, achieving sub-pixel resolution (0.1 pixel) in displacement measurements while maintaining control accuracy over micro and nano movements.
Solution Approach 2:
The patent changes the measurement parameter from mechanical position to electrical capacitance. By measuring changes in capacitance between fixed and movable electrodes, the system achieves high precision displacement measurement without the limitations of mechanical systems, directly addressing the contradiction between measurement precision and control accuracy.
2Reliability
If standard equipment tolerances are accepted in load frame systems, then device complexity is reduced, but test result accuracy deteriorates due to the amplification of minor losses at small sample scales
Solution Approach 1:
The patent replaces mechanical measurement and control systems with capacitive sensing technology. This eliminates the accumulation of mechanical tolerances and minor losses that plague conventional systems, particularly when testing small samples where such losses are magnified. The electrical field-based measurement provides superior reliability without proportionally increasing device complexity.
Solution Approach 2:
The patent uses capacitive fields as a non-contact copy or representation of the mechanical displacement. Instead of directly measuring physical position with mechanical sensors, the system creates an electrical field model of the displacement, which can be measured with much higher precision and without the mechanical losses that affect test result accuracy.
3Manufacturing precision
If high precision control over micro and nano movements is implemented, then measurement precision improves, but device complexity increases due to the need for specialized actuators and sensors
Solution Approach 1:
The patent designs the capacitive sensor system to serve multiple functions: it measures displacement, provides feedback for closed-loop control, and characterizes the mechanical properties of the test specimen. This multi-functionality reduces the need for separate specialized components, achieving high precision control over micro and nano movements without proportionally increasing device complexity.
Solution Approach 2:
The patent implements closed-loop feedback control using capacitive sensors that continuously monitor displacement and feed this information back to the actuator control system. This feedback mechanism enables high precision control of micro and nano movements by continuously correcting for deviations, achieving the desired manufacturing precision while managing device complexity through intelligent control rather than purely mechanical means.
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 system achieves high resolution (up to 0.1 pixel displacement) and accuracy in materials testing, effectively controlling micro and nano movements and loads, thereby improving data quality and reducing the impact of equipment tolerances.
Implementation Method 1
The actuator assembly has a ball screw assembly, with a ball screw and a ball screw nut rotatably coupled to the ball screw
Implementation Method 2
The displacement sensor is configured to measure displacement of at least one of the first and second crossheads
Data Source
AI summary
A load frame assembly including a frame assembly, a servomotor, an actuator, a first crosshead assembly, a second crosshead assembly, a load frame and a displacement sensor. The servomotor is coupled to the frame and includes a control system. The actuator is coupled to the first crosshead assembly and provides for moving the first crosshead assembly relative to the frame assembly. The actuator comprises a ball screw assembly having a ball screw and a ball screw nut. The load frame is coupled to one of the crosshead assemblies. The displacement sensor is associated with the frame assembly and is configured to measure displacement by the crossheads relative to the frame assembly.