Journal of Mechatronics and Artificial Intelligence in Engineering
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In Memoriam. About the micro-rhinic dysplasia
Get PDFMicro-rhinic Dysplasia is a common finding in patients who seek for dentofacial correction have several degrees of facial growth commitment and can be associated with another growth syndromes like the Rotation Syndrome, for instance, which may increase the degree of difficulty in corrective treatment of malocclusion. The most challenging malocclusion treatment in an individual with Micro-rhinic Dysplasia is the anterior open bite, mostly when associated with prognathism. The aim of this manuscript is to show through patients records the clinical and cephalometric characteristics of Micro-rhinic Dysplasia alone or associated with other craniofacial growth alterations and their consequences in malocclusion treatment
Two-stroke engine with constant crank angular velocity
Get PDFThe work is devoted to the dynamics of a two-stroke engine. The engine used in sea vessels is considered. A new scheme of the crank mechanism of a two-stroke engine is proposed. An elastic hinge with a given angular characteristic (dependence of the restoring moment on the angle of rotation of the crank) is supposed to be installed between the strut and the crank. The work shows that with certain parameters of the hinge it is possible to obtain a constant angular velocity of the crank for any angle of rotation of the crank. Currently, flywheel inertia can account for up to 80 percent of all moving parts in an engine. Since the mass of engines is large, eliminating the flywheel from the engine design or reducing its mass may be a promising direction in the production of two-stroke engines. The proposed hinge is a structure in which an elastic element (spring or air spring) moves between circular guides of a calculated shape, resulting in a given hinge characteristic. In this work, an air spring was chosen as the elastic element of the hinge, since in this case it becomes possible to change the characteristics of the hinge by changing the pressure in the air spring. The shape of the guides is such that when adding the characteristic of an elastic hinge to the existing characteristic of the engine, an “ideal” characteristic of the considered engine with an elastic hinge is obtained, at which the angular velocity of the crank will be constant. When the angular velocity of the crank changes, a different characteristic of the hinge is required. In progress it is supposed to change the characteristics of the elastic hinge by changing the pressure in the air spring, which is the elastic element of the hinge. It turned out that by changing the initial excess pressure in the air spring it is possible to compensate for the change in the characteristics of the hinge required for the angular velocity of the crank to remain constant at any angle of rotation when its value changes. The results of these studies can be used both in the production of two-stroke engines and for any two-stroke engines
Automatic vibration control method for grasping end of flexible joint robot
Get PDFBecause flexible robots have flexible components such as reducers, there are problems of accuracy deviation and end vibration in the process of external interference and trajectory tracking. This leads to the proposal of a Sliding Mode Control Approach Based on RBF Neural Network (SMC-RBF) parameter optimization. This method is mainly applied to reduce the end vibration and running position error of flexible robot. Firstly, the Newton-Euler method is used to establish the dynamic model of robot considering joint flexibility. At the same time, the experiment optimizes the Sliding Mode Control (SMC) method through RBF neural network. The experiments verify the control methods of the two-joint flexible robot and the six-joint flexible robot respectively. In the control of two-joint robot, the maximum tracking curve error of SMC is only about 0.25 rad under the interference of pulse signal; And the recovery time is only about 1 s. In the control of 6-joint robot, the maximum error of RBF-sliding mode control method on XYZ axis is 0.7 mm, 0.25 mm and 1.25 mm respectively; The error on three axes is smaller than that of traditional PD control method. The results demonstrate that the tracking error of the improved mode control is small, the chattering phenomenon of the robot system is weakened as well
Production analysis of manufacturing industry in a single vacation policy under disaster
Get PDFThe disaster in queueing system with second optional service is considered. Arriving customer of this system will receive the essential service and optional second service if needed. When the system is interrupted by the disaster, the server initiates the repair period making all the customer leave the system immediately. The server, when idle, takes single vacation. The disaster cannot happen when server is under vacation or in repair period. The above queueing system is analysed using supplementary variable technique to obtain the probability generating function for various parameters and effects of parameters are explained graphically with numerical illustrations
Application of optimized CNN algorithm in landslide boundary detection
Get PDFLandslide, as a natural geological phenomenon with great harm, seriously threatens human social activities and life safety. It has a variety of latent and immeasurable destructiveness, which has a significant impact on the economic losses in rural areas. Therefore, it is urgent to take measures to accurately identify landslides to reduce their negative impacts. However, traditional manual visual interpretation has been unable to meet the current needs for emergency rescue of landslides, so computer intelligent methods have been paid attention to. This study proposes a new recognition network to address the problem of low accuracy of intelligent landslide boundary recognition methods. Firstly, the experiment incorporated boundary structure information into the Full Convolutional Network (FCN) for optimization, and constructed an Improved Full Convolutional Network (IFCN) model to better achieve image reconstruction. After that, Attention Mechanism (AM) is further introduced to achieve accurate detection of landslide boundaries in images, namely the IFCN-AM model. The attention mechanism introduced include spatial attention mechanism and multi-channel attention mechanism. Both are responsible for enhancing the language representation ability of the model and aggregating the interrelated features between different channels. The experimental results show that IFCN-AM has a 3 % to 7 % improvement in accuracy, recall, F1 value, and MIoU value
Gabor wavelet transform combined with area CNN in appearance intelligent detection of stayed cables
Get PDFThe major structure for transmitting forces in a cable-stayed bridge is the stay cable. If the stay cable system fails, the whole bridge will collapse. At present, there is no very mature technical means for the detection of bridge cables. The most common method is for workers to perform regular manual inspection and replacement of cables. Although the defect condition of the cable can be detected to a certain extent, the real-time monitoring of its health cannot be realized. Therefore, the research used the median filter, mean standardization method and Retinex algorithm to preprocess the image data. And after extracting the stay cable picture’s macroscopic characteristics using the Gabor wavelet transform, it implemented image segmentation using the OTSU approach. The obtained feature images were applied to the Faster Regional Convolution Neural Network (RCNN) recognition model to detect microscopic defects. During the research, the training efficiency of traditional Convolution Neural Network (CNN) was not high. Therefore, Faster RCNN built a cable defect recognition model. Based on this, the research built an intelligent detection model for apparent defects of stay cables based on Gabor wavelet transform and improved RCNN. Through the experimental analysis, the model built for the study has a recognition accuracy rate of 94.14 %, which can achieve dynamic bridge health monitoring and instantly identify the condition of the stay cables, and maintain the safety of the bridge
Six-DOF modular robotic arm bearing chatter suppression algorithm
Get PDFRobotic arms are frequently utilized in contemporary industrial production since they offer great qualities like high precision and low mass. How to minimize robotic arm tremors in order to maximize their control effect has emerged as one of the most critical issues to be resolved with the continued development of industrial intelligence. The study uses a combination of PID control and an artificial fish swarm technique to optimize the parameters and confirm the simulation control effect based on the kinematic analysis of a six-degree-of-freedom (Six-DOF) modular robotic arm. The findings demonstrated that the suggested fusion approach converges to zero in 80 iterations and has a recall of 0.893 and 0.785 at an accuracy of 0.8 and 0.9, respectively. The robotic arm control system’s average control effect is 42.96 %, which is a respectable control performance. In the second and third studies, the fusion approach stabilized actuator end tremor suppression after 0.01 s and 0.0001 s, respectively. It shows that the technique can effectively suppress robotic arm bearing tremor and has high flexibility for robotic arm tremor suppression, which offers trustworthy technological support for improving the motion control system of industrial robots
Decarbonisation options of existing thermal power plant burning natural gas
Get PDFNowadays power industry faces deepest crises ever with unprecedented prices shocks and climate challenges at the same time. From one hand we realise the need of energy transformation of power industry towards more sustainable future with climate neutral technologies. From the other hand it become obvious that this change could not happen immediately and transition period is needed with some fossil fuel technology still playing an important role as a back-up for renewable energy sources. The biggest question what is the best and cost-efficient way to decarbonise existing thermal power generation. We try to address it on the example of existing combined cycle gas turbine (CCGT) power plant fuelled by natural gas. Clearly the following possible options were identified: 1) replacement of natural gas with alternative gases, such as green hydrogen, bio or synthetic methane, 2) carbon capture and underground storage (CCS) in geological formations, 3) carbon capture, liquefaction and export, 4) carbon capture and utilisation (CCU). US giant General Electric in its publication “Decarbonizing gas turbines through carbon capture” is considering similar options for decarbonising of gas turbines. They divide it into two approaches: 1) pre-combustion by using a zero or carbon neutral fuels, such as hydrogen, synthetic methane, biofuels or ammonia and 2) post-combustion by removing carbon from the plant exhaust, using liquid or solid sorbents or oxy-fuel cycles. In this publication we try to compare these different options, despite they are not clearly comparable. For the analysis we take natural gas fired CCGT plant Riga TPP-2 in Latvia with installed capacity of 881 MW (in condensing mode)
Public perceptions of CCUS in Central and Eastern Europe – implications for community engagement
Get PDFCarbon capture, utilization, and storage (CCUS) is emerging as a subject of major interest for EU climate policy due to their potential role in avoiding hard-to-abate CO2 emissions, as well as to lead to “negative emissions” through direct air capture or bioenergy with carbon capture and storage. Despite CCUS technologies being deployed since the 1970s, their widespread implementation is still challenged by a range of factors, including policy inertia, high costs, and relative novelty in the public discourse. In particular, as CCUS emerges slowly into the realm of public and political debate, opinions on these technologies and associated projects are easily changeable and affected by a range of factors, which make concerted public and community engagement extremely important for deploying them where they matter most. The Central and Eastern Europe (CEE) region is characterized by a higher-than-average economic dependence on heavy industry, old assets and infrastructure, and a high occurrence of regions where the transition to climate neutrality will have a significant impact on local economies, employment, and social welfare [1]. CCUS could play an important role in decarbonizing the heavy industry sectors of the region, particularly given the potentially significant storage capabilities of countries such as Romania and Poland, as well as emerging storage potential in the Black Sea and Eastern Mediterranean Sea. However, climate policy in these jurisdictions is sluggish, and there is a general failure to approach CCUS in a systematic way, with targeted application to sectors where it can have the highest impact, such as cement and oil refining. As a result, the public debate around CCUS is practically non-existent, and where public opinions do emerge, they may be significantly influenced by the context of a particular project and generate significant resistance based on the relationship with project developers, the amplification of perceived risks, and the lack of appropriate explanations of costs, benefits and risks. This in turn can lead to a reticence of political stakeholders to commit to deploying CCUS, causing the public debate to further stagnate and creating a vicious circle whereby opportunities to familiarize the public with these technologies (well in advance of their deployment) are missed. In order to deploy CCUS at pace and scale, as part of the catching-up climate policies of CEE countries, public perception of CCUS must be thoroughly researched and developed into appropriate guidelines for community engagement by project developers. There is experience in the region – the feasibility study for Romania’s planned Getica CCS demonstrator (subsequently abandoned) included comprehensive research into the perceptions of local communities, and a toolkit for communications around CCUS by project developers. Similarly, learnings from Poland’s failed Belchatow CCS project can serve to re-assess the state of public opinion on CCS, and how the local and national-level contexts for CCUS perceptions interact. The CEE region has significant potential for deploying CCUS, and public perception must be an integral part of planning as the region moves into the key decade of 2030-2040 for implementing large-scale projects
CO2 geological storage prospects of Lithuania – update
Get PDFThe CO2 geological storage assessment in the Cambrian saline aquifers in west Lithuania is considerably improved by 3D seismic survey of the Gargždai Elevation and Syderiai Uplift. The CO2 storage capacity of the Syderiai site is assessed as large as 56.7 Mt (area 62 km2) owing to the high reservoir properties (average porosity 17 % and permeability 400 mD) of the Middle Cambrian saline aquifer of 50 m thick and 1458-1508 m deep. The tectonic uplift is controlled by the large-scale Telšiai strike-slip fault. The Syderiai site was initially considered as the potential UGS site. The acreage of the Gargždai Elevation, comprising six depleting oil fields, is assessed 133 km2 and the storage volume is evaluated 31.3 Mt. The main challenging parameter is a poor average porosity (7 %) and fractured type of reservoir (permeability about 10 mD) about 70 m thick and 2200 m deep. A residual oil zone (ROZ) assessment suggests are very high protentional for CO2 combination in west Lithuania which is the only prospective site known in the Baltic region of this kind