Volume 5: Dynamics, Vibration, and Control最新文献

{"title":"Design of a Low-Cost Autonomous Mobile Robot for Outdoor Applications","authors":"Cameron Morris, Vedang Chauhan","doi":"10.1115/imece2022-96093","DOIUrl":"https://doi.org/10.1115/imece2022-96093","url":null,"abstract":"\u0000 In today’s world, many companies are looking for low-cost automated alternatives to industrial processes that can save time and money. Autonomous Mobile Robots (AMR’s) are an appealing new alternative to complete tasks with base chassis and interchangeable tops that allow for standardization along with multifunctionality. With improvements in motors, motor controllers, location technology, vision, and IR sensors and a variety of other sensors, many complex tasks are attainable and simpler to complete. AMR’s can also be adapted to the operating environment whether it is on a manufacturing floor or in the field exposed to different elements. Using this equipment and implementing an odometry positioning method, an AMR can be designed to travel to pre-planned coordinates and perform desired tasks at each target point. Calculations to select hardware that satisfies requirements for this application are discussed. Strategies for motion control and positioning are also shown along with their advantages and disadvantages. Other subsystems are designed and attached to the robot to allow the robot to operate with awareness of its environment. To test the AMR’s abilities, a series of experiments are designed to analyze the robot’s strengths and identify sources of error. With these tests, data is collected to compare the position calculation accuracy and analyze the speed and orientation of the robot. Based on these results, there will be suggested adjustments for future work of AMRs in this field.","PeriodicalId":302047,"journal":{"name":"Volume 5: Dynamics, Vibration, and Control","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114614103","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Long Short-Term Memory Neural Networks for Predicting Dynamic Response of Structures of High Complexities","authors":"Yabin Liao, Biswas Poudel, Priyanshu Kumar, Mark Sensemier","doi":"10.1115/imece2022-97025","DOIUrl":"https://doi.org/10.1115/imece2022-97025","url":null,"abstract":"\u0000 This paper presents an initial investigation on the feasibility of modeling structural dynamics of complex structures using the Long Short-Time Memory (LSTM) deep learning neural networks, and predicting the structures’ vibration responses due to random excitation. LSTM networks are applied to the responses of various simulated systems subjected to random excitation loads, including mass-spring-damper systems with linear or nonlinear Duffing springs, a cantilever beam, and a tapered, cambered wing structure. Given a known force input, the dynamic response of the system is simulated in Matlab or ANSYS, which is used to train the LSTM model. In the case of mass-spring-damper and beam systems, the excellent agreement between the test and LSTM-predicted responses demonstrates the potential of the LSTM method for predicting vibration responses. In the case of cambered wing structure, the LSTM shows difficulties in dealing with responses consisting of multiple modes. Parametric studies are also performed to discover possible means for performance improvement. The studied learning parameters include the number of hidden units, the number of LSTM layers, and the size of train data. It is found that all these parameters have significant impact on the model accuracy. While it is always beneficial to have as much and there could be an optimal setting for the number of is not determined by the studies, they provide valuable directions to.","PeriodicalId":302047,"journal":{"name":"Volume 5: Dynamics, Vibration, and Control","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129657909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Neural Network-Augmented Bayesian Approach to Uncertain Parameter Estimation in Nonlinear Dynamic Systems","authors":"Roja Zakeri, P. Shankar","doi":"10.1115/imece2022-95563","DOIUrl":"https://doi.org/10.1115/imece2022-95563","url":null,"abstract":"\u0000 Many engineered and physical systems contain uncertain parameters and knowing their accurate value is essential to system analysis and design. In this paper, we propose a new approach that combines an artificial neural network with a Bayesian algorithm to achieve better computational efficiency in estimating an unknown parameter of a dynamic system. We utilize neural networks (NN) to start the Particle Markov Chain Monte Carlo (PMCMC) algorithm from a better initial guess of the unknown parameters which is closer to the target value of the parameter. The neural network that is trained on kinematic data are used to provide a rough initial estimate of the unknown parameter. This rough estimate is then used as the initial guess for the Particle Markov Chain Monte Carlo (PMCMC) method. The effectiveness of the new algorithm is first evaluated on a nonlinear benchmark problem — the Van der Pol oscillator. In estimating the damping factor using the NN estimate as the initial guess, the number of iterations required by the PMCMC is shown to reduce by 40% as compared to initializing the algorithm with a random guess. The new methodology was then applied to determine the unknown joint torques of a 7-DOF research robot based on the known joint position and velocities. Multiple neural networks based on different combinations of join position and velocities were trained and used to estimate the initial guess for the PMCMC algorithm. In each of the cases, there was a reduction in the number of iterations required for the PMCMC algorithm to converge as compared to a random initial guess with an average reduction around 30%.","PeriodicalId":302047,"journal":{"name":"Volume 5: Dynamics, Vibration, and Control","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130575779","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Low-Cost Portable High-Speed Data Logging","authors":"Colton Kerr, J. Rogers","doi":"10.1115/imece2022-94016","DOIUrl":"https://doi.org/10.1115/imece2022-94016","url":null,"abstract":"\u0000 This research describes a low-cost design for high-speed, portable, and configurable data acquisition and logging. Drone launch from in-flight aircraft produces short-duration, impactlike peak stresses in aircraft structure. Testing environments such as on aircraft require portable data acquisition hardware systems. Commercially available data acquisition systems typically have at least one drawback of being expensive, not portable, not high speed, or not configurable. These drawbacks make it difficult to use commercial systems in field experiments such as on aircraft in flight. This research describes a data logging system that is low-cost (materials < $200), portable (< 1kg), has one single-ended high-speed analog input channel (20k samples/second), and a resolution of 12 bits. The microcontroller used is a Digilent WiFire board with a microchip PIC32MZ2048EFG100 microcontroller. This microcontroller is programmed using Simulink and is configurable in its sample rate, data type, number of channels, and resolution. Data are logged locally on an SD card using an open-source OpenLager device that was developed by drone racing company dRonin for high-speed data. Data logging is in binary format, and the 12-bit value is logged as two 8-bit (upper and lower) bytes due to limitations of the OpenLager. A MATLAB script reassembles the bytes in a postprocessing step. Performance of the prototype is compared to commercial data logging systems by simultaneous logging of one event. A hammer strike force-impulse experiment is used as a proxy for the stresses in aircraft structure during impact-like events. Conclusions and recommendations on the use of the new system and existing commercial systems are made based on the results of the experiments. The experiment was designed to log signals from a strain gage-Wheatstone bridge-amplifier system, but the prototype is configurable and may be used in any applications that require portable logging of voltage signals with sample rates in the 20 kHz range.","PeriodicalId":302047,"journal":{"name":"Volume 5: Dynamics, Vibration, and Control","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130490614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of Inequality Constraints Without Using Lagrange Multipliers With Applications to Classical Dynamical Systems","authors":"Brennan McCann, Morad Nazari, F. Udwadia","doi":"10.1115/imece2022-94362","DOIUrl":"https://doi.org/10.1115/imece2022-94362","url":null,"abstract":"\u0000 The fundamental equation of mechanics (FEM) for constrained motion analysis provides a way to obtain control accelerations necessary to satisfy some set of holonomic or non-holonomic constraints. The methodology provides the control necessary to either perfectly satisfy or minimize the error in all the constraints and does not require computation of Lagrange multipliers. Furthermore, this framework is capable of addressing various types of constraints, and can treat systems that are under-, fully-, or over-constrained, conveniently. The FEM formulation has most commonly been applied to a variety of classes of equality constraints. Some attempts at extending this approach to inequality constraints have been presented in the literature, including applying slack variables to provide freedom in the constraint and diffeomorphisms to map equality constraints to bounded spaces. However, these approaches have different associated advantages and drawbacks. In order to bridge the benefits of both methodologies and mitigate their issues, this work proposes a treatment of holonomic inequality constraints within the framework of the FEM wherea class of functions built on the error and Gaussian distribution functions is leveraged to treat inequality constraints on several classical dynamical case studies. The proposed technique is applied to several classes of holonomic, solitary or one-sided inequalities, and bounding inequalities for a spring-mass-damper, an inverted pendulum, and an inverted pendulum on a cart, illustrating this approach’s broad applicability to mechanical systems.","PeriodicalId":302047,"journal":{"name":"Volume 5: Dynamics, Vibration, and Control","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126087908","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nonlinear Vibration Analysis of High-Speed Rotating Pre-Twisted FGM Blades Considering Initial Large Deformations","authors":"Yukun Chen, G. Jin, Tiangui Ye, Shanjun Li","doi":"10.1115/imece2022-94254","DOIUrl":"https://doi.org/10.1115/imece2022-94254","url":null,"abstract":"\u0000 Rotating pre-twisted blades made of functionally graded materials (FGMs) have broad application prospects in engineering owing to their superior properties. With a high-velocity rotational motion, the blades would exhibit large-amplitude deformations due to the severe centrifugal forces and their vibration behaviors might be affected. This paper presents a nonlinear vibration analysis of rotating pre-twisted FGM blades considering the large-amplitude deformations caused by centrifugal forces. Based on the Carrera unified formulation and 3-D nonlinear elasticity shell theory, a prior large deformation analysis of the FGM blades under centrifugal forces is performed considering the geometrical nonlinear characteristics. The nonlinear vibration analysis of the system about the equilibrium position is then performed taking into consideration the deformed configuration and rotational motion. A systematic comparison of the present results with the 3D FEM solutions is performed to verify the correctness of the present method in determining the large deformation and vibration characteristics of the high-speed rotating pre-twisted FGM blades. The comparative performances of the linear and nonlinear models are assessed in the vibration analysis of the pre-twisted FGM blades with different rotating speeds and material parameters.","PeriodicalId":302047,"journal":{"name":"Volume 5: Dynamics, Vibration, and Control","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122913388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Aerial Vehicle Rapid 3D Map Generation for Safe Landing Area Detection","authors":"Akin Tatoglu, Cheng Chun Yin, Brianna Cervello, Antonio Corrado, Bernard Balko, Kiwon Sohn","doi":"10.1115/imece2022-95849","DOIUrl":"https://doi.org/10.1115/imece2022-95849","url":null,"abstract":"\u0000 This project assists in building a robust control LiDAR scanning unit that helps aerial vehicles land autonomously. The LiDAR scans the terrain, detects static or dynamic obstacles, and helps target safe landing areas. The whole terrain scanning system uses a robust control system to control the LiDAR position to collect point clouds around the environment and use ICP (Iterative Closest Point) to create a 3D point cloud map. In the robust control system, IMU (Inertial Measurement Unit) is used to control the servo to ensure the control system had an accurate target angle for the LiDAR scanning. MSAC algorithm is used in the 3D mapping to help the system detect flat areas for an aerial vehicle to land. This project also shows the different voxelization levels (1 × 1 and 5 × 5) of the flat surfaces and the maximum point to plane distance changed (0.05, 0.25, 1, and 10). Also, an exaggerated voxelization level (10 × 10) was investigated to get a rapid first-level estimation of flat surfaces. The results of the different values and comparisons are also noted and shared. This study is the variable resolution mapping and perception portion of our full-scale heterogeneous localization and mapping research project of Autonomous Mobile Robotics Research Group.","PeriodicalId":302047,"journal":{"name":"Volume 5: Dynamics, Vibration, and Control","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128134491","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multichannel Electromechanical Impedance Structural Diagnostics in Plate Specimens","authors":"Funmilola Nwokocha, Andrei N. Zagrai, David Hunter","doi":"10.1115/imece2022-95937","DOIUrl":"https://doi.org/10.1115/imece2022-95937","url":null,"abstract":"\u0000 Structural health monitoring has become increasingly important in order to save costs and improve the safety of structures. One of the methods of monitoring the health of structures is the use of thin piezoelectric wafer active sensors to measure the electromechanical impedance of the integrated structure/sensor system. These wafers have proved to be efficient in structural diagnostics as they serve as both actuator and sensor for the structures they are attached to. In this contribution, a multichannel unit, which is an arrangement of single miniaturized electro-mechanical impedance units, is utilized to measure the electromechanical impedance of a complex plate structure. The multi-channel unit was validated by measuring the impedance signature of a cantilevered beam and comparing the results with those obtained using a desktop impedance analyzer, the HP4192A.\u0000 A numerical modelling of 2D structures was performed using finite element analysis on COMSOL multiphysics software. This was validated by comparing the electromechanical impedance data obtained from the numerical modelling with analytical and experimental data. The specimen was numerically modelled for each sensor bonded to its surface and the results were analyzed. Furthermore, all the sensors on the specimen were simultaneously excited within the same frequency band and the electromechanical impedance data from each sensor was compared with those from same sensor when only one sensor was excited. The results were analyzed and discussed. A numerical modelling of the specimen with all the sensors simultaneously excited was also carried out and the results were compared with experimental data.\u0000 The multi-channel unit was also used for damage detection in plate specimens. Structural damage was introduced in the specimen and the electromechanical impedance signatures of the damaged specimen was measured. The result was analyzed and compared with results obtained from the pristine specimen in the same frequency band. The data from each sensor was analyzed and discussed. The efficiency of piezoelectric sensors for detecting damages in structures was highlighted and the effect of sensor location on the accuracy of detecting damages in structures was presented. This suggests optimum sensor location for damage detection in structures.\u0000 Finally, the multichannel unit was used to measure damage detection in the specimen at different frequencies when excited simultaneously by all sensors. The electromechanical impedance data obtained was analyzed and compared with data from the pristine specimen and in the single frequency band. The ability of piezoelectric sensor to detect damages in simultaneously varying frequency bands was explored. Recommendations for the application of the multichannel electro-mechanical impedance approach in structural health monitoring were given.","PeriodicalId":302047,"journal":{"name":"Volume 5: Dynamics, Vibration, and Control","volume":"172 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133991798","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Comparative Study of Feasible Trajectories for an Under-Actuated Two-Link Bipedal Walking Robot With Hybrid Zero Dynamics Based Motion Planning","authors":"Shri Ishwaryaa S. V., Akshay Kumar, V. Sangwan","doi":"10.1115/imece2022-95603","DOIUrl":"https://doi.org/10.1115/imece2022-95603","url":null,"abstract":"\u0000 Control of under-actuated bipedal walking robots has been an active area of research for many decades. Hybrid zero dynamics based motion planning is a technique very commonly used to plan trajectories for these robots. Exploring the solution space of optimal trajectories obtained through this method can potentially increase our understanding of bipedal walking by observing possible speeds, energy consumption etc. Very few studies are available with detailed solution space explorations of walking trajectories obtained through this method. This paper attempts to fill this gap by performing a hybrid zero dynamics based solution space exploration for an under-actuated two-link biped with a point mass at the hip as a proxy for the torso. The parameters of the biped chosen are similar to that of an average human. In addition, a comparison of the solutions obtained for different objective functions is carried out. Lastly, a non-dimensional analysis is done to identify if there are any dominant terms in the dynamics of the walking trajectories.","PeriodicalId":302047,"journal":{"name":"Volume 5: Dynamics, Vibration, and Control","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115575027","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of Rotor-Stator Rub-Impact on Post-Resonance Backward Whirl Excitation","authors":"Rafath Abdul Nasar, Mohammad A. AL-Shudeifat","doi":"10.1115/imece2022-95354","DOIUrl":"https://doi.org/10.1115/imece2022-95354","url":null,"abstract":"\u0000 It has been indicated in the literature to many factors that contribute to faults in rotor dynamical systems such as rubbing impact at stator-rotor contact. Accordingly, the appearance of rubbing impact is investigated here as one of the major factors that could excite the post-resonance backward whirl (Po-BW) phenomena in rotors. Therefore, the effect of rotor-stator rub impact on Po-BW excitation is numerically studied here with a Jeffcott rotor model. Accordingly, vertical and horizontal rotor configurations are considered here with rub-impact. The rubbing between the stator and the rotor is modeled by using both Heaviside function and the exact time calculation during the numerical simulation for comparison and to guarantee whirl results convergence. It is found that at a time step of order 10−6 in the numerical integration both Heaviside function and exact contact time calculations produce similar convergent results. In addition, the obtained numerical simulation results show that the stator-rotor rub-impact is found to excite the Po-BW and affects their recurrence and intensity. Accordingly, the current study provides a more insight to the impact of rotor-stator rubbing on Po-BW excitation. Therefore, the rotor-stator rub-impact is found to be one of the main factors that lead to excite the Po-BW during the rotor transient operation.","PeriodicalId":302047,"journal":{"name":"Volume 5: Dynamics, Vibration, and Control","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123606177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}