In sensor systems, most sensors are single-point detection, and it is challenging to develop a multi-point sensor where multiple points can be sensed. This work reports a low-cost relative humidity (RH) sensor relying on intensity-variation based on the side coupling technique using polymer optical fiber, where three sensors are integrated into a single illuminating fiber. The sensor structure contains the twisting of two fiber three times and is coated with agarose-gel, while a rise in humidity causes change in refractive index (RI) between two twisted fibers. The experimental results reveal that the sensors provide a linear relationship between 20% to 80% RH with a sensitivity of 0.4636 μW/%, 0.4402 μW/%, and 0.4153 μW/%. Detection limits are 1.57%, 1.79%, and 2.02% for sensor-1, sensor-2, and sensor-3, respectively, while the bend radius of the sensor probe is 10 mm. When RH is increased from 80%, resulting in more sensitive as well as sensor’s sensitivity rises when the bend radius reduces. A lower detection limit and increased sensitivity are obtained with a coating of agarose-gel. In addition, the novel RH sensor is a cost-effective solution that offers the benefits of decent reversibility, rapid reaction time (about 1 sec), and temperature dependency.

Silica fiber under high pressure increases the risk of fiber breakage or permanent deformation, which may cause sensor failure due to mechanical strength limitations. High pressure can also induce birefringence in optical fiber. In this study, we present a simple design and low-cost high pressure sensor using polymer optical fiber (POF) based on the intensity-variation technique. A side-coupling mechanism in the sensor structure is adopted, which varies the intensity with applied pressure. Two POFs are twisted together to create a sensing region where the light is launched in the first fiber and measurement is taken from the second fiber. In sensing phenomena, cladding mode frustrated total internal reflection occurs when pressure increases. Silicone gel is used in the pressure chamber for sealing and preventing leakage. The sensor structure is able to detect high pressure in the MPa range, where we tested up to 4 MPa. For higher sensitivity, twisted and bend structure is analyzed, and sensitivity is achieved at about 432.21 nW/MPa. However, twisted helical structure is adopted to enhance sensing range which is about 50 cm. The proposed high-pressure sensor structure is easier to fabricate and has high stability because it doesn’t require any destructive method as compared to other conventional methods.

Traditional product design evaluation processes are resource-intensive and time-consuming, resulting in unsustainably higher costs and longer lead times. Therefore, sustainable product design evaluation has become an increasingly crucial aspect of product design, focusing on creating a high-efficiency, high-reliability, and low-carbon-emission approach. In this study, we proposed an integrated approach that combines manual design evaluation based on the analytic hierarchy process (AHP) with an automatic design evaluation based on a ResNet-50 network in order to develop a sustainable design evaluation method. First, the evaluation level and indicators for the shape design of a tail-light were defined using the AHP. We followed this by establishing a determination matrix and weight coefficients for the design indicators to create a manual design evaluation model. Second, tail-light shape image datasets were manually annotated based on the evaluation indicators, and design datasets were constructed. The ResNet-50 algorithm was introduced to train the datasets, and the automatic evaluation model for product design was constructed through training and tuning. Finally, we validated the feasibility and effectiveness of the product design evaluation method, which was based on AHP and ResNet-50, by comparing the results obtained using both manual design and automatic design evaluations. The results showed that the proposed sustainable product design evaluation model provides an efficient and reliable method for evaluating product design, improves the decision-making process, and empowers the design and development process. The model enhances resource efficiency and economic sustainability.

Fully reconfigurable tactile information sensing is indispensable of intelligent robotics intended for varieties of human-machine interactive applications. Current focus of the existing tactile sensors is still mostly on determining contact forces with high sensitivity or large measuring range, yet other tactile information especially the occurrence of incipient slip is equally noteworthy for stable grasping. Herein this paper, a tactile sensing array consisted of four separate sensing units of similar pattern is proposed, which allows different areas of the gripper-object interface to change individually. A seesaw-like prototype based on floating electrode structure is introduced into the design of each sensing unit, drastically reducing unexpected coupling induced by the coupled response between in-plane stretch and out-of-plane pressure. The fabricated prototype of the tactile sensing array is of great flexibility, and has displayed excellent multi-dimensional force sensing capability in terms of high sensitivity (2.38 kPa ^-1 in normal direction and 0.199 kPa ^-1 for tangential directions) and large measuring range (265 kPa in normal direction and 90 kPa for tangential directions). A feasible scheme based on empirical mode decomposition (EMD) was applied for validation of incipient slippage. Detected vibration component of first intrinsic mode function (IMF1) signals as well as real-time variation of stationary tangential force to normal force ratio were both taken into consideration to further divide actual incipient slip from possible re-grasping. During extensive in-hand experiments, distinguished features were all successfully confirmed of incipient slippage than possible re-grasping circumstances, implying full capability of detecting multi-dimensional contact forces and dividing incipient slippage simultaneously of this presented sensing array.