Journal of Mechanical Engineering, Automation and Control Systems
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A review on positioning techniques of mobile robots
Get PDFIn this article, we have reviewed the available positioning, localization and navigation techniques for mobile robots. Different localization techniques based on diverse technologies are compared with one another, along with diverse algorithms and techniques for analyzing this information. The article highlights algorithms based on odometry, triangulation, visual analysis, and marker detection. The analysis included global, local, and personal location. One acquires knowledge on which method is suitable for indoor use and which for outdoor use, as well as the appropriate environmental conditions for each. The accuracy of the individual methods was compared with that of integrated systems consisting of several methods. For practical knowledge, it is possible to determine whether a particular method is cost-effective for a particular solution and to compare the expenses involved
Checking the manufacturing of Simões Network 10 – SN10 through surface electromyography (sEMG) – case report study
Get PDFUse of functional orthopedic appliances (FOA) in the treatment of malocclusion and Temporomandibular Disorders (TMD) has been proved to be effective but there is still questions to be answered like the muscular action of the referred appliances. The aim of this study is checking through a proven protocol of surface electromyography (sEMG) to study muscular action of FOA to check to check if it is correctly manufactured. The appliance studied is a Simões Network 10 – SN10 to treat Class II malocclusion of retrognathia. The sEMG was collected 1 patients with class II malocclusion with retrognathia who belong to a 164 volunteers with malocclusion, in two times T1 before installation of the FOA in mouth, T2 15 minutes after the FOA installation in the mouth. sEMG data of bilateral masseter, bilateral temporal and bilateral suprahyoid muscles using conditioner signals module from Lynx Electronics Ltda with 8 channels, model EMG1000; software AqDAnalysis 4,18 from Lynx Electronics Ltda.; Software Lynx BioInspector 1,8r; passive surface electrodes (Ag/AgCl) from Noraxon Dual Electrodes (USA); dischargeable reference electrodes Kendall Meditrace (Ag/AgCl) – Canada were used for the sEMG measurements. Frequency calibration was 2000 Hz, with 2048 sample by channel and time 1,024 seconds, and filters regulation was 20 Hz and 1000 Hz. With the FOA in the mouth all measurements improved with a more simetrical sEMG in T2 in rest and isometric contraction measurements. The protocol used to check the manufacturing of functional orthopedic appliances using surface EMG proved to be a valid tool in this case report study. Further investigations are needed to confirm this protocol and check if the same happens with other types of functional orthopedics appliances
Use of fibre optic systems for detection of small leaks on trunk pipelines
Get PDFThis paper is devoted to the issue of efficiency of application of fibre optic leak detection systems for identification of small leaks on trunk pipelines. The main methods of leak detection currently in use have been considered, and parametric and fibre optic LDS have been selected for comparative analysis. In the course of the research a model of product leakage from an underground oil pipeline equipped with a fibre-optic LDS was built in the COMSOL Multiphysics software package. The result of the simulation was the estimated time of leak identification by the fibre-optic system, which turned out to be much shorter than that of the parametric LDS. Compensable environmental damage for each type of system was then calculated, confirming the effectiveness of fibre optic LDS for detecting small leaks on trunk pipelines due to the significant reduction in compensable damage
Preparation and properties of polyamide elastomers by a new synthesis route of Michael addition reaction
Get PDFAt present, the mainstream industrial synthesis method of polyamide is still bulk fusion polymerization, which is not in line with the concept of green synthesis because of the high threshold of reaction conditions and large energy consumption. Based on this, a new synthesis route of polyamide elastomer was studied in this paper. By synthesizing the end-functionalized long carbon chain diacrylamide (DDA) containing amide bonds, the synthesis mechanism was made by the thiol double bond Michael addition reaction. A series of polyamide elastomers with different ratios of hard and soft segments were synthesized by using dimercaptan chain extenders with different molecular weights. The results showed that the new synthesis route successfully prepared DDA and polyamide elastomers. The mechanical properties of the products were excellent, and the strain rate could reach 383 %. Tensile strength up to 23.08 MPa. The synthesis route has the characteristics of simple reaction process, mild reaction conditions and high reaction conversion rate. It provides theoretical guidance for the new synthesis route of polyamide elastomer
Vibration technology to produce highly active hydrated lime
Get PDFThis paper proposes a mechanical dispersion method of hydrated lime in a vibrating activator equipped with special blades that operate in a resonant mode. It has been found that during the vibro-activation process, hydrated lime consistently passes through proportionately increasing stages of dynamic viscosity, slowing its growth and ceasing dispersion. A new vibration method for determining the viscosity of the hydrated lime-water system has been developed. The effect of vibration treatment on changes in the dispersion of calcium hydroxide was studied. It has been found that vibration-treated lime, compared to conventional hydrated lime, has new properties: the ability to form durable coatings due to accelerated carbonization
Mathematical modeling of the possibility of creating interresonance discrete-continuous vibration technological equipment without a spring
Get PDFIn the article is implemented interresonance mechanical oscillating system vibrational technological equipment, which provides using two continuous of connected area successively to working body vibrational machines. Disturbance of the structure is carried out by applying a variable-sign power supply voltage to the reactive continuous section, where in interaction with the magnetic field from the permanent magnets, a variable-sign disturbance force occurs. Inertial forces from the reactive continuous section are transferred to the intermediate continuous section, which resonates with the working body. In fact, an interresonance discrete-continuous oscillating system is obtained in which there are no springs. The function of springs is performed by bodies with distributed parameters that have elastic properties. Based on the Krylov-Duncan functions, a system of equations was formed that establishes the amplitude of oscillations of the working body. The amplitude-frequency characteristic of the discrete-continuous system was studied, which confirms the possibility of creating interresonance oscillating systems of vibrating technological equipment without springs
Investigation of the propagation characteristics of train-induced vibration at Guangzhou Baiyun railway station
Get PDFIn densely populated cities, the increasing popularity of railways and urban rail transit interchange hubs has led to the extensive use of land resources and raised concerns about the environment, especially the inevitable noise and vibration impact. This study aims to identify the propagation patterns of roof structure vibrations in railway complexes through experimental research, with the premise of maintaining normal train operation and safety, in order to lay a foundation for developing vibration mitigation strategies and optimizing functional layout. The results found that the train-induced vibrations are strongest at track level, but decrease as they move vertically and horizontally. Vibrations from passing trains are most noticeable within a single floor slab and beams, with minimal transmission at the base of columns
Demagnetization optimization of hybrid excitation eddy current damper under intensive impact load
No full textThe hybrid excitation eddy current damper is a novel principle damper characterized by high reliability, simple structure, and controllable magnetic field. Under intensive impact loads, hybrid excitation electromagnetic damping can induce demagnetization effects, resulting in significant fluctuations of the electromagnetic damping force at 6-8 ms. To mitigate this phenomenon, this study established a finite element model of the hybrid excitation damper using COMSOL and developed a control module based on a BP neural network in Simulink. Through co-simulation of COMSOL and Simulink, the difference between the maximum and minimum electromagnetic damping force at 6-8ms is reduced from 45 kN to 5 kN. This research provides valuable technical references for the optimization and practical application of eddy current dampers
Detection method for underwater dock joints: underwater sonar imaging based on 3D technology
Get PDFIn the detection of surface defects in underwater structures, traditional methods using manual diving are inefficient. Equipment such as underwater high-definition cameras and underwater laser imaging face significant signal attenuation in deep and turbid environments, and the information contained in two-dimensional sonar images is limited, making it difficult to meet accuracy requirements. To address these shortcomings, a detection method based on sonar imaging for underwater docks using three-dimensional (3D) reconstruction is proposed. This method first reduces environmental interference through preprocessing. Then, emit sound waves towards the underwater target and receive the returning signals, which are converted into digital signals. Next, perform 3D modeling and visualization. Finally, a detailed analysis of the 3D images is conducted to identify, analyze, and assess the severity and distribution patterns of defects. The experimental results show that the 3D scanning sonar imaging detection technology can effectively detect targets and accurately identify misalignment in caisson joints, meeting practical application requirements
Method of experimental determination of the effective area of a pneumatic spring of high-speed rolling stock
Get PDFThe object of research is a pneumatic spring of high-speed rolling stock of the railway. The method of experimental static testing of a pneumatic spring of high-speed rolling stock is presented. Based on experimental tests, the “force-strain” dependences of a pneumatic spring are obtained when the pressure gauge in the pneumatic spring changes from 2.5 atm up to 5.0 atm. Using a thermodynamic model, a quadratic equation is found to determine the effective area of a pneumatic spring. It is established that when the pressure gauge in the pneumatic spring changes from 2.5 atm up to 5.0 atm the effective area of the pneumatic spring varies from 0.231 m2 to 0.306 m2. The scientific novelty lies in the fact that for the first time, on the basis of static experiments, the change in the effective area of the pneumatic spring of high-speed rolling stock depending on the value of the gauge pressure in the spring was established. This will make it possible to determine the forces acting on the pneumatic spring in different operating conditions, ensuring the required level of safety of rolling stock