The demand for innovative sensor technologies capable of measuring complex movements is rising. Traditional sensors struggle to accurately capture both linear and rotational displacements simultaneously, underscoring the need for advancements in this area. In a recent study published in the journal Scientific Reports, researchers have developed a novel simultaneous rotary and linear displacement sensor based on soft pneumatic sensing chambers (SPSCs).
Presented sensor and its test setup, including two degrees of freedom displacement mechanism and displacement measurement sensors. Image Credit: https://www.nature.com/articles/s41598-024-59168-3
The development of this sensor addresses this limitation by leveraging SPSCs, offering a unique solution for multi-dimensional displacement measurements. Its ability to accurately detect and quantify both linear and rotational movements makes it a highly effective and reliable tool for various applications.
With its innovative approach to displacement sensing, this sensor is set to enhance measurement techniques in industrial settings, research environments, and interactive body applications, offering significant improvements in both performance and adaptability.
Background
Traditional displacement sensors often struggle to accurately measure both linear and rotational movements simultaneously, highlighting a pressing need for more versatile and adaptable sensing capabilities across various applications.
Utilizing innovative SPSC technology is crucial to address this challenge, providing a unique solution that enhances sensor functionality. The development of a sensor capable of detecting and quantifying both types of displacements effectively is essential. Such advancements will enable the precise and reliable capture of complex movements, filling a critical gap in the field of sensor technology.
The Current Study
In this study, researchers developed a sensor capable of measuring both rotary and linear displacements simultaneously using SPSCs. They employed a systematic and detailed approach to design, ensuring the sensor's accuracy and reliability in capturing various types of movements.
The various stages of the workflow are described as follows:
Design and Fabrication: The chambers were constructed using soft and flexible materials such as acrylonitrile butadiene styrene (ABS), polyamide (PA), and polyurethane (PU). The design process involved optimizing the chamber's geometry and material properties to enhance sensitivity and responsiveness to different types of displacements.
Integration and Sensor System Setup: Once the chambers were fabricated, they were integrated into the sensor system along with pressure sensors for data collection. The sensor setup included BMP280 sensors to measure pressure and temperature in the SPSCs and ambient air. Additionally, the setup incorporated stepper motors to generate linear and rotary movements, which were measured after calibration.
Data Collection and Processing: The sensor's performance was evaluated through a series of tests involving linear position adjustments at 100 μm intervals and back-and-forth rotational movements in 1.8° steps. The sensor was subjected to longitudinal movements over multiple cycles to assess its stability and accuracy. Furthermore, the sensor's ability to compensate for temperature variations within the range of 17–28 °C was tested to ensure reliable operation under changing environmental conditions. Data collection involved recording pressure variations within the SPSCs as the sensor underwent linear and rotational movements.
Machine Learning Algorithms: Machine learning algorithms were employed to analyze the collected data and extract meaningful insights. Specifically, the random forest regressor algorithm from the Sklearn library was utilized to model the relationship between the pressure data and the corresponding linear and rotational displacements.
Laboratory Testing and Validation: Laboratory testing was conducted to validate the sensor's performance in measuring simultaneous rotary and linear displacements. The sensor was then subjected to controlled movements in different directions, and the pressure data was recorded to evaluate the sensor's accuracy and precision. The results were compared with the expected values to assess the sensor's reliability and consistency in measuring multi-dimensional movements.
Results & Discussion
The results of the laboratory testing demonstrated the sensor's ability to accurately measure both linear and rotational movements. The researchers show the sensor's response to varying linear speeds ranging from 0.1 mm/second to 3 mm/second and rotational speeds ranging from 1 rpm to 15 rpm to observe how changes in linear and rotational speeds impact the accuracy and precision of the measurements.
The data collected showed promising outcomes, indicating the sensor's effectiveness in capturing various types of movements. Furthermore, the sensor's stability and repeatability were found to be promising through multiple cycles of longitudinal movements over three days. The Abaqus software further validated the sensor's performance, highlighting its robustness and reliability in real-world applications.
Conclusion
In conclusion, the study successfully developed and tested a novel soft sensor for simultaneous linear and rotational displacement measurement. Utilizing SPSCs and advanced calibration methods, the sensor demonstrated high accuracy with 0.49 mm precision in linear movements and 5.4° in rotational movements within specified ranges.
The machine learning approach, particularly employing the random forest algorithm, outperformed traditional methods, showcasing the sensor's robustness and reliability. Additionally, its all-polymer composition and compatibility with electromagnetic environments position it as an ideal solution for applications that demand precise multi-dimensional displacement measurements in challenging conditions.
Journal Reference
Ghaffari, A., Hojjat, Y. Simultaneous rotary and linear displacement sensor based on soft pneumatic sensing chambers. Scientific Reports 14, 8317 (2024). https://doi.org/10.1038/s41598-024-59168-3, https://www.nature.com/articles/s41598-024-59168-3