Journal of Mechanical Engineering, Automation and Control Systems
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Simões Network 2 (SN2): A special model for special needing
Get PDFFunctional Orthopedics appliances must follow strict rules of construction and respect the correct indications, to achieve the proposed goals. The approach must be individualized for each patient according to each needing. Dr Wilma Alexandre Simões created a network of appliances, with no similarity with other appliances created by other authors. Her appliances respect rigid scientific fundamentals and provide for the clinician special tools for solving different types of occlusopathies. Here we present some rules, developed, and scientifically supported by the authors, in order to optimize the use of one of Simões Network called SN2
Modelling and experimental investigation of the vibratory conveyor operating conditions
Get PDFThe paper’s objective is to study the dynamic parameters and operating conditions of the vibratory conveyor, which is based on the double-mass oscillatory system and equipped with the pull-type (single-cycle) electromagnetic exciter. The scientific novelty consists in substantiating the conveying capacity of various standard sizes of bolts at different operating conditions defined by the input parameters, particularly supplied voltage. In order to describe the conveying tray vibrations, the simplified mathematical model of the conveyor’s double-mass oscillatory system is developed using the Euler-Lagrange equations and is numerically solved in the Mathematica software with the help of the Runge-Kutta methods. The experimental investigations are carried out at the Vibroengineering Laboratory of Lviv Polytechnic National University and are focused on testing the conveying speed of various bolts at different motion conditions: detachable (bouncing, hopping, jumping over the conveying surface) and non-detachable (sliding along the conveying surface). The obtained results show the basic kinematic parameters of the conveying tray motion at different voltages supplied to the actuating electromagnet and the dependencies of the conveying speeds of various bolts at different motion conditions mentioned above. The paper may be useful for designers and researchers while improving and implementing similar vibratory equipment in various industries
Construction and benchmark of an autonomous tracked mobile robot system
Get PDFRobots require a certain set of skills to perceive and analyse the environment and act accordingly. For tracked mobile robots getting good odometry data from sensory information is a challenging key prerequisite to perform in an unstructured dynamic environment, thus an essential issue in the tracked mobile robotics domain. In this article, we construct a ROS-based tracked mobile robot system taking the Jaguar V4 mobile robot as the base platform. On which several visual odometry solutions based on different cameras and methods (Intel RealSense T265, Zed camera, RTAB-Map RGBD) are integrated and benchmark comparison is performed. Analysis of new challenges faced by different methods while applied on a tracked vehicle as well as recommendations and conclusions are presented. Intel RealSense T265 solution proved to perform well in uncertain conditions which involves bounded vibrations and low lighting conditions with low latency, which result in good map generation. Further evaluations with a path planning algorithm and Intel RealSense T265 were conducted to test the effect of the robot’s motion profiles on odometry data accuracy
Effect of the geometrical parameters on the vehicle's moving stability
Get PDFTo enhance the moving stability and safety of vehicles, kinematics and dynamics model of the vehicle consisting of a guided front wheel and a free rear wheel is established based on the model of a four-wheeled vehicle when the vehicle moves on the curve-road. The effect of the geometrical parameters and dynamics parameters including the factor of the moving stability, vehicle moving speed, lateral stiffness parameters of the front and rear wheels, vehicle mass, vehicle length on the vehicle moving stability and safety is then simulated and analyzed, respectively. The research results indicate that the operating parameters of the vehicle greatly affect the vehicle moving stability. The lateral stiffness parameters of the front and rear wheels should be increased while the vehicle mass needs to be reduced in the operating condition of the vehicle to enhance the vehicle moving stability. Besides, the vehicle length L should be reduced and the longitudinal distance of a needs to be distributed by 0.95×a to further improve the vehicle moving stability
Experimental study on influencing factors of anchorage performance of concrete bonded rebars
Get PDFHilti re-100 structural adhesive is used to plant reinforcement in concrete, and the factors affecting the anchorage performance of planted reinforcement are analyzed. The Planting reinforcement of the concrete specimen and the specimen with reinforcement anchored in concrete in advance are compared. A total of 36 groups of tests were carried out, including 27 groups of embedded reinforcement tests and 9 groups of embedded reinforcement tests. The test mainly analyzes the influence of concrete strength, reinforcement diameter and planting depth on the anchorage performance of planting reinforcement. There are three failure modes in the test, which are the separation failure of reinforcement and structural adhesive, the tensile failure of reinforcement and the separation failure of reinforcement and concrete. Through the analysis of the test data, the bond slip data curve is obtained
Occlusal plane parallel to camper plane: reality or fallacy? A tomographic study on human Sambaqui skeletal remains
Get PDFIntroduction: Since long time ago, dentists had used parallelism with Camper plane as a reference to establish a correct occlusal plane. However, in the literature, there are several different landmarks used to trace the occlusal plane and there are also many researchers questioning this parallelism. To evaluate it, we used ancient skulls from Human Sambaqui skeletal remains. The authors choose an ancient population because they were submitted to same environmental conditions, avoiding bias in craniofacial growth epigenetic stimuli. Methodology: For this work we analyzed tomographies of 27 well preserved adult skulls. The program used was Vista Dent Pro 2.1. Camper plane was determined according to the original points described by Peter Camper. We used the four occlusal planes more cited in the literature. Results: None of the occlusal planes evaluated on this study, showed parallelism with Camper plane. The occlusal plane determined by posterior teeth was the one that showed less divergence but still with a high SD and mediana. Conclusion: In Sambaqui ancient population, Camper plane was not a reliable reference to trace occlusal plane. It is necessary further investigations to find a better reference for prosthetic, orthodontic, functional orthopedics or orthognathic surgery purpose
Recent advancements of signal processing and artificial intelligence in the fault detection of rolling element bearings: a review
Get PDFA rolling element bearing is a common component in household and industrial machines. Even a minor fault in this section has a negative impact on the machinery's overall operation. As a result, the industry suffers significant financial losses, and this damage can potentially result in catastrophic failures. Therefore, even a little fault in the rolling element bearings must be recognized and remedied as soon as possible. Many ways for detecting REB defects have been created in recent years, and new methods are being introduced on a daily basis. This article will provide a summary of such methods, with a focus on vibration analysis techniques. The newest advancements in this field will be recognizable to readers of this article. Anyone interested in defect diagnostics of rolling element bearings can utilize this material
Experimental study on dynamic bending rigidity of aluminium cable steel reinforced
Get PDFThe dynamic bending rigidity of aluminium cable steel reinforced (ACSR) is a key parameter for analyzing the breeze vibration, galloping and de-icing vibration response of overhead transmission lines. In this paper, the calculation formula of the dynamic bending rigidity under axial force is derived based on the theory of Bernoulli-Euler beam. The dynamic response of one typical ACSR with different spans and different axial forces are studied by white-noise excitation and hammer excitation. The variation rules of dynamic bending rigidity of ACSR are presented. The comparison between the experimental results of the static and dynamic bending rigidity shows that the dynamic bending rigidity of the ACSR is much larger than the static bending rigidity
Experimental study of the lap motion trajectory of vibratory finishing machine
Get PDFVibratory equipment is widely used for performing various finishing processes, machining and forcing of different parts and materials. Numerous researchers and technologists pay specific attention to the possibilities of implementing vibration-driven machinery for conducting the lapping and polishing operations on flat surfaces. The present paper is dedicated to studying the laps kinematic parameters of the vibratory finishing machine actuated by six electromagnets. The paper’s scientific novelty consists in the experimental verification of the previously modelled and simulated circular trajectories of the laps under different operational conditions. The methodology of research contains two basic stages: changing the excitation frequency at the constant traction force and changing the traction force at the constant excitation frequency. The improved 3D-design of the vibratory finishing machine was developed in the SolidWorks software. The experimental prototype was implemented in practice, and full-scale tests were carried out using the WitMotion sensors and software. Based on the obtained experimental data, the trajectories of the machine’s laps were constructed and analyzed in the MathCad software. The research results substantiate the possibilities of providing circular oscillations of the laps at different operational conditions. The results can be used by technologists and engineers while choosing the appropriate design and control parameters for similar vibratory equipment intended for lapping and polishing of flat surfaces
Multi-axis vibration test technology of satellite based on vector-fixture’s design and applications
Get PDFAiming at the problems that the three-direction uniaxial sequential vibration test cannot effectively simulate the real launch environment of the satellite, and the high cost of the multi-axis shaker and the limitation of engineering application, the multi-axis vibration test scheme based on vector-fixture is proposed. Taking the vibration magnitude of uniaxial vibration test on the satellite mounting surface as equivalent reference, the appropriate vector direction is determined to carry out vector-fixture design. By analyzing the multi-axial vibration test data of the real structure of a satellite, it can be seen that: The “satellite-fixture” mounting surface can reach the set vibration magnitude at low frequencies, and undertest occurs at high frequency due to structural resonance and other factors; By optimizing the control strategy, the degree of over-test and under-test in the three directions can be balanced. According to the mission characteristics and development cycle of micro-nano satellites, this paper provides an efficient vibration test scheme