Real time parameter measurement cannot be carried out to dynamic ring parts during automation ring rolling processes so that rolling process parameters cannot be adjusted in time. Considering effects ...of shaping of ring rolling parts, a visual measurement platform was set up and a machine vision-based non-contact real -time measurement method was put forward. This article improves the subpixel level edge extraction algorithm to extract edge data information of circular rolling pieces. Based on the characteristics of circular rolling pieces, an RG-Hough transform method is proposed to fit the detected edge data information. The conversion relationship between pixel and actual sizes were determined in combination with the camera calibration to gain parameters of ring rolling parts. Measurements of ring parts (OD: 462.12mm; and ID: 315.53mm) were applied to verify the effectiveness of our method. Our measurement error is ±0.25mm and our average speed can be up to 104ms/frame. Our study can provide powerful technical supports for intelligent control of ring rolling pieces.
Trajectory tracking plays a notable role in unmanned surface vehicles (USV), especially for the emerging intelligent aquaculture, as the level of integration, high-efficiency, and low-labor-intensity ...of such USV is determined by trajectory tracking. Here, we report a generic trajectory tracking control system for a paddle boat by establishing a three-degree-of-freedom kinematics model, which could precisely characterize the relationship between velocities, forces and moments of the paddle boat. A Pixhawk 4 as the core controller of the hardware system could be integrated with the other hardware submodules and could complete the wireless data transmission, monitoring and remote control functions. Meanwhile, we establish a fuzzy rule table, consider the advantages of line-of-sight (LOS) guidance and fuzzy adaptive proportional-integral-differential (PID) algorithm, combine the two parts and apply them as the key algorithm in the trajectory tracking of the paddle boat. Demonstrations include trajectory tracking effect at different velocities, turning effect at left-turn moment, and trajectory tracking effect at different turning angles. The results show that the paddle boat is able to travel under the trajectory formed by following the planned waypoints within the error allowed, which is called effective trajectory tracking. And can offer an alternative pathway toward achieving effective trajectory tracking control in advanced intelligent aquaculture USV for smartly and wirelessly operated pond drug spraying.
This study proposes a constrained hot compression-molding (CHCM) technique for preparing Bi2Te3-based alloys. This method overcomes the problem of easy cleavage and destruction for the zone-melted ...Bi2Te3-based alloy, which is beneficial to improve the material utilization rate and thermoelectric devices yield in the commercial manufacturing process. The stress field distribution inside the CHCM specimen is explored via finite element analysis. The compressive strength of the CHCM sample is above 44 MPa, which is about 38% higher than that of the zone melting (ZM) material. Meanwhile, the CHCM sample shows a much lower electrical conductivity and thermal conductivity, but a higher Seebeck coefficient than that of the ZM sample, which is mainly due to the increase of the line defect concentration induced by the CHCM process. Finally, a maximum thermoelectric figure of merit (ZT) value of 0.6 was achieved for CHCM sample.
Thermal management of power lithium-ion battery modules is very important to avoid thermal problems such as overheating and out of control, the study of thermal behavior of battery modules can ...provide guidance for the design and optimization of modules and thermal management. In this paper, a 3d thermal model of the power lithium-ion battery module is established based on STARCCM+ by using computational fluid dynamics (CFD) method, and a grid independence simulation test is used to determine the number of grids, the temperature distribution is analyzed under the condition of 1C charge current. The research results show that the internal temperature rises gradually with the charge going on, the temperature distribution of the cells is basically symmetrical. When the heat transfer coefficient is 5W/(m
2
⋅K) and the natural convective air inlet temperature is 300K, the module temperature uniformity is good. But because of the maximum temperature slightly higher than the temperature of thermal runaway, additional cooling methods need to be considered to cool the battery.
TRIP effect is one of the important features for TRIP steel. A Nb-Mo microalloyed TRIP steel was developed by employing two different soaking time during annealing, and tensile tests at three ...different strain rate for specimens after annealing were performed. The microstructures and the volume fraction of retained martensite were examined and analyzed. The result indicated that TRIP steel showed significantly different behaviour at different strain rates. The ultimate tensile strength and total elongation decreased with the strain rate increasing. The dynamic strain aging effect might occur at low strain rate. With shorter soaking time during annealing, microstructure with ultra-refined grain size could be achieved. Fracture surfaces were different at different strain rate. As strain rate increases, the fraction of retained austenite to martensite transformation at failure point decreases which leads to the difference of mechanical properties.
Two different types of dual phase steels DP780 were manufactured and investigated. Steel A contained higher carbon, the other one B had lower carbon with Nb added. The mechanical properties and ...microstructures were analyzed and compared. The hole expansion test were conducted to evaluate stretch-flangeability. An Ultra Micro-Indentation System (UMIS) were employed to carry out the nano-hardness test to check the nano-hardness of ferrite and martensite. The result showed that for DP steel A, higher over-aging temperature during manufacturing would result in lower ultimate tensile strength with martensite partly resolved, which would lead to higher stretch-flangeability. In comparison with A, steel B with lower carbon and Nb added exhibited higher stretch-flangeability, which was related to the refined grain size of ferrite. It could be concluded that for dual phase steel stretch-flangeability was mainly affected by the strength difference between ferrite and martensite. Generally the bigger the strength difference is, the lower the stretch-flangeability is. Either decreasing martensite strength by increasing over-aging temperature or increasing ferrite strength by adding Nb could improve the stretch-flangeability. The same parts formed from the two different dual phase steel were compared. There was crack in some edge area during forming for steel A, while the part formed from Steel B showed good quality without crack, which verified the stretch-flangeability improvement was very effective. However, increasing over-aging temperature during manufacturing is not easy to be implemented and it could result in lower ultimate tensile strength, which may not meet the strength requirement. Adding Nb is considered to be a more feasible and effective way to improve ferrite strength and stretch-flangeability for dual phase steel DP780.
Tomato picking robots can save labor and improve production efficiency, which is of great significance for facility tomato planting. The picking mode of the Tomato Picking Robot has an important ...impact on fruit picking quality and efficiency. At present, in the process of fruit picking, the rough recognition of fruit positioning needs compensation accuracy. The picking mode is usually to capture the fruit in a large range and then separate the fruit peduncles in a specific position. In the process of grasping and pulling the fruit, it may cause damage to the fruit and plant, which will reduce the fruit quality. Moreover, The retention length of peduncles is also difficult to control, resulting in difficulties in transportation and storage. Therefore, the prediction, location and segmentation of separation points on tomato images are an important guarantee for efficient and lossless harvest. In this study considering the changeable conditions such as light change and branches and leaves interference, YOLO V5 is used to confirm the position relationship between tomatoes and peduncles. The region of interest for peduncles picking is reduced according to the growth characteristics of the fruit. Then, taking the boundary boxes center of the peduncles as the picking points, the corresponding depth information is obtained and the robot is controlled to complete the picking task. The experimental results show that this method can recognize and locate tomato picking points under complex near-color backgrounds. The average recognition time of a single frame image is 104 ms, which meets the real-time requirements of automatic picking. Compared with the SSD algorithm, it has obvious advantages.
An effective battery thermal management system (BTMS) of power battery module for electric vehicles (EVs) plays a decisive role in battery life, cost, and safety in use. A BTMS method for a ...lithium-ion battery module, which is consisting of 12 prismatic cells, is proposed based on liquid cooling in the present work. Three circuitous channels embedded with a cooling plate are studied. In addition, the reliability and scientificity of the numerical model are verified by cooling performance tests. The simulation and test for this BTMS under a 3C discharging and charging rate were performed. Meanwhile, the performance evaluations of the battery module by considering different cooling conditions and battery arrangement are investigated numerically. With the help of the numerical model and test, the effects of flow area, mass flow rate, and cell gap on the battery temperature are examined and discussed. Simulation results illustrate that the larger flow area is experienced with a lower maximum temperature. BTMS with five channels design exhibits better heat dissipation behavior, and the maximum temperature and temperature difference under 80 g/s mass flow rate is about 45°C. Then, increases of maximum temperature and temperature difference are shown under lower mass flow rate, and the peak temperature at the lowest flow rate of 2 g/s is equal to 79.89°C, while it increases to 80 g/s, the peak temperature drops down to 47.43°C. Moreover, the lower the cell gap is, the worse the cooling performance is. Consequently, this study of this paper will provide a theoretical and an experimental basis for improving the battery module thermal behavior and BTMS strategy.
In the process of ring rolling, the rolling process parameters of the equipment have an important influence on the forming process and forming quality of the ring. The ring rolling process has the ...characteristics of non-linearity, easy interference, rapid growth and asymmetric shape. These factors have resulted in the inability to measure the dimensions of the ring directly. In this work, we established a vision measurement system, and performed a series of operations on the image, such as threshold segmentation, hot ring contour extraction, oxide scale filtering, inner and outer ring extraction, inner and outer ring sampling, data visualization, etc. Moreover, we measured the dynamic dimension characteristics of small and medium size hot ring in the rolling process. The circularity, dimensional difference, center swing and vibration characteristics of the ring in the rolling process are obtained through the algorithm design, which characterizing the size change of the hot ring. The study provides practical methods and theoretical guidance for the subsequent measurement of large-size rings and feedback control of the rolling ring.
Due to the instability of stamping and welding process, there will be missing welding in the production process of auto parts, and multiple welding spots appear on the multi angle joint surface of ...the workpiece. However, the manual detection is inefficient and the accuracy is poor, and the leakage often occurs in the above situations. In view of the above problems, an intelligent detection algorithm of solder joints based on deep learning YOLOv3 framework is proposed. The machine vision equipment for inspecting solder joint is built, and the welding spot inspection experiment is carried out on the platform. A large number of welding spot images are collected and samples are enhanced to obtain different sample data. By comparing this method with the Hough circle transform for circle fitting of solder joints in the image, the experimental results show that the proposed deep learning-based YOLOv3 framework solder joint detection effect is better.
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