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Tarnita, Daniela, Ionut Daniel Geonea, Doina Pisla, Giuseppe Carbone, Bogdan Gherman, Nicoleta Tohanean, Paul Tucan, Cristian Abrudan e Danut Nicolae Tarnita. "Analysis of Dynamic Behavior of ParReEx Robot Used in Upper Limb Rehabilitation". Applied Sciences 12, n. 15 (7 agosto 2022): 7907. http://dx.doi.org/10.3390/app12157907.
Testo completoAbstract (sommario):
This paper presents a dynamic analysis of the ParReEx multibody mechanism, which has been designed for human wrist joint rehabilitation. The starting point of the research is a virtual prototype of the ParReEx multibody mechanism. This model is used to simulate the dynamics of the multibody mechanism using ADAMS in three simulation scenarios: (a) rigid kinematic elements without friction in joints, (b) rigid kinematic elements with friction in joints, and (c) kinematic elements as deformable solids with friction in joints. In all three cases, the robot is used by a virtual patient in the form of a mannequin. Results such as the connecting forces in the kinematic joints and the torques necessary to operate the ParReEx robot modules are obtained by dynamic simulation in MSC.ADAMS. The torques obtained by numerical simulation are compared with those obtained experimentally. Finite element structural optimization (FEA) of the flexion/extension multibody mechanism module is performed. The results demonstrate the operational safety of the ParReEx multibody mechanism, which is structurally capable of supporting the external loads to which it is subjected.
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Lefebvre, F., I. Rogowski, N. Long e Y. Blache. "Influence of marker weights optimization on scapular kinematics estimated with a multibody kinematic optimization". Journal of Biomechanics 159 (ottobre 2023): 111795. http://dx.doi.org/10.1016/j.jbiomech.2023.111795.
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Douadi, Lounis, Davide Spinello, Wail Gueaieb e Hassan Sarfraz. "Planar kinematics analysis of a snake-like robot". Robotica 32, n. 5 (4 novembre 2013): 659–75. http://dx.doi.org/10.1017/s026357471300091x.
Testo completoAbstract (sommario):
SUMMARYThis paper presents the kinematics of a planar multibody vehicle which is aimed at the exploration, data collection, non-destructive testing and general autonomous navigation and operations in confined environments such as pipelines. The robot is made of several identical modules hinged by passive revolute joints. Every module is actuated with four active revolute joints and can be regarded as a parallel mechanism on a mobile platform. The proposed kinematics allows to overcome the nonholonomic kinematic constraint, which characterizes typical wheeled robots, resulting into a higher number of degrees of freedom and therefore augmented actuation inputs. Singularities in the kinematics of the modules are analytically identified. We present the dimensional synthesis of the length of the arms obtained as the solution of an optimization problem with respect to a suitable dexterity index. Simulation results illustrate a kinematic control path following inside pipes. Critical scenarios such as 135° elbows and concentric restriction are explored. Path following shows the kinematic capability of deployment of the robot for autonomous operations in pipelines, with feedback implemented by on-board sensors.
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Hall, Andrew, Thomas Uchida, Francis Loh, Chad Schmitke e John Mcphee. "Reduction of a Vehicle Multibody Dynamic Model Using Homotopy Optimization". Archive of Mechanical Engineering 60, n. 1 (1 marzo 2013): 23–35. http://dx.doi.org/10.2478/meceng-2013-0002.
Testo completoAbstract (sommario):
Despite the ever-increasing computational power of modern processors, the reduction of complex multibody dynamic models remains an important topic of investigation, particularly for design optimization, sensitivity analysis, parameter identification, and controller tuning tasks, which can require hundreds or thousands of simulations. In this work, we first develop a high-fidelity model of a production sports utility vehicle in Adams/Car. Single-link equivalent kinematic quarter-car (SLEKQ, pronounced “sleek”) models for the front and rear suspensions are then developed in MapleSim. To avoid the computational complexity associated with introducing bushings or kinematic loops, all suspension linkages are lumped into a single unsprung mass at each corner of the vehicle. The SLEKQ models are designed to replicate the kinematic behaviour of a full suspension model using lookup tables or polynomial functions, which are obtained from the high-fidelity Adams model in this work. The predictive capability of each SLEKQ model relies on the use of appropriate parameters for the nonlinear spring and damper, which include the stiffness and damping contributions of the bushings, and the unsprung mass. Homotopy optimization is used to identify the parameters that minimize the difference between the responses of the Adams and MapleSim models. Finally, the SLEKQ models are assembled to construct a reduced 10-degree-of-freedom model of the full vehicle, the dynamic performance of which is validated against that of the high-fidelity Adams model using four-post heave and pitch tests.
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Delyová, Ingrid, Darina Hroncová, Peter Frankovský, Peter Sivák, Ján Kostka e Vojtech Neumann. "Application of direct and inverse kinematics and dynamics in motion planning of manipulator links". International Journal of Applied Mechanics and Engineering 28, n. 3 (29 settembre 2023): 53–64. http://dx.doi.org/10.59441/ijame/169515.
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For the synthesis of manipulators and robots, an accurate analysis of the movements of the individual links is essential. This thesis deals with motion planning of the effector of a multi-linked manipulator. An important topic in this area is the orientation and position of links and kinematic pairs in space. In particular, attention should be paid to the position of their endpoint as well as other significant points. Trajectory planning allows the manipulator to perform complex tasks, such as picking and placing objects or following a particular path in space. Overall, trajectory planning of a multibody manipulator involves a combination of direct and inverse kinematics calculations, as well as control theory and optimization techniques. It is an important process enabling manipulators to perform complex tasks such as assembly, handling and inspection. In the design of robot kinematic structures, simulation programs are currently used for their kinematic and dynamic analysis. The proposed manipulator was first solved by inverse kinematics problem in Matlab. Subsequently, the trajectories of the end-effector were determined in Matlab by a direct kinematics problem. In Simulink, using the SimMechanics library, the inverse problem of dynamics was used to determine the trajectories of the moments.
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Blache, Y., M. Degot, M. Begon, S. Duprey e I. Rogowski. "Does double calibration coupled with a closed loop multibody kinematic optimization improve scapular kinematic estimates?" Computer Methods in Biomechanics and Biomedical Engineering 23, sup1 (19 ottobre 2020): S35—S37. http://dx.doi.org/10.1080/10255842.2020.1811505.
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Manrique-Escobar, Camilo Andres, Carmine Maria Pappalardo e Domenico Guida. "A Multibody System Approach for the Systematic Development of a Closed-Chain Kinematic Model for Two-Wheeled Vehicles". Machines 9, n. 11 (20 ottobre 2021): 245. http://dx.doi.org/10.3390/machines9110245.
Testo completoAbstract (sommario):
In this investigation, a closed-chain kinematic model for two-wheeled vehicles is devised. The kinematic model developed in this work is general and, therefore, it is suitable for describing the complex geometry of the motion of both bicycles and motorcycles. Since the proposed kinematic model is systematically developed in the paper by employing a sound multibody system approach, which is grounded on the use of a straightforward closed-chain kinematic description, it allows for readily evaluating the effectiveness of two alternative methods to formulate the wheel-road contact constraints. The methods employed for this purpose are a technique based on the geometry of the vector cross-product and a strategy based on a simple surface parameterization of the front wheel. To this end, considering a kinematically driven vehicle system, a comparative analysis is performed to analyze the geometry of the contact between the front wheel of the vehicle and the ground, which represents a fundamental problem in the study of the motion of two-wheeled vehicles in general. Subsequently, an exhaustive and extensive numerical analysis, based on the systematic multibody approach mentioned before, is carried out in this work to study the system kinematics in detail. Furthermore, the orientation of the front assembly, which includes the frontal fork, the handlebars, and the front wheel in a seamless subsystem, is implicitly formulated through the definition of three successive rotations, and this approach is used to propose an explicit formulation of its inherent set of Euler angles. In general, the numerical results developed in the present work compare favorably with those found in the literature about vehicle kinematics and contact geometry.
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Blanco-Claraco, Jose-Luis, Antonio Leanza e Giulio Reina. "A general framework for modeling and dynamic simulation of multibody systems using factor graphs". Nonlinear Dynamics 105, n. 3 (28 luglio 2021): 2031–53. http://dx.doi.org/10.1007/s11071-021-06731-6.
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AbstractIn this paper, we present a novel general framework grounded in the factor graph theory to solve kinematic and dynamic problems for multibody systems. Although the motion of multibody systems is considered to be a well-studied problem and various methods have been proposed for its solution, a unified approach providing an intuitive interpretation is still pursued. We describe how to build factor graphs to model and simulate multibody systems using both, independent and dependent coordinates. Then, batch optimization or a fixed lag smoother can be applied to solve the underlying optimization problem that results in a highly sparse nonlinear minimization problem. The proposed framework has been tested in extensive simulations and validated against a commercial multibody software. We release a reference implementation as an open-source C++ library, based on the GTSAM framework, a well-known estimation library. Simulations of forward and inverse dynamics are presented, showing comparable accuracy with classical approaches. The proposed factor graph-based framework has the potential to be integrated into applications related with motion estimation and parameter identification of complex mechanical systems, ranging from mechanisms to vehicles, or robot manipulators.
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Blache, Y., M. Degot, S. Duprey, M. Begon e I. Rogowski. "Closed-loop multibody kinematic optimization coupled with double calibration improves scapular kinematic estimates in asymptomatic population". Journal of Biomechanics 126 (settembre 2021): 110653. http://dx.doi.org/10.1016/j.jbiomech.2021.110653.
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Kaidash, Mykhailo, e Serhii Selevych. "Dynamics and kinematics of complex mechanical systems harnessing multibody dynamic program". Bulletin of Electrical Engineering and Informatics 13, n. 6 (1 dicembre 2024): 3928–37. http://dx.doi.org/10.11591/eei.v13i6.7721.
Testo completoAbstract (sommario):
Understanding the behavior and performance of engineering applications like machines, transport machines, manipulators, and mechanisms like gears relies heavily on the study of the dynamics and kinematics of complex mechanical systems. This article provides a comprehensive overview of recent findings and advancements in this field. The purpose of this work is to provide an in-depth introduction to the theoretical and practical considerations involved in assessing the dynamic and kinematic properties of such complex systems. Understanding forces, torques, displacements, and velocities is highlighted as crucial to the design and study of complex mechanical systems, and the underlying mathematical models and concepts that control their motion are investigated. This paper also evaluates and critiques the most current developments in modeling and simulation approaches such as finite element analysis (FEA), computational dynamics, and optimization strategies. The multidisciplinary aspect of the topic and its potential to progress numerous engineering, robotics, and industrial applications constitute the topic's scientific uniqueness. The results include various advanced modeling and simulation techniques like FEA, computational dynamics, and multibody dynamics simulation. In conclusion, this article compiles a lot of information on the dynamics and kinematics of sophisticated mechanical systems, such as machines, transport machines, manipulators, and mechanisms.
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Sohl, Garett A., e James E. Bobrow. "A Recursive Multibody Dynamics and Sensitivity Algorithm for Branched Kinematic Chains". Journal of Dynamic Systems, Measurement, and Control 123, n. 3 (10 luglio 2000): 391–99. http://dx.doi.org/10.1115/1.1376121.
Testo completoAbstract (sommario):
In this work an efficient dynamics algorithm is developed, which is applicable to a wide range of multibody systems, including underactuated systems, branched or tree-topology systems, robots, and walking machines. The dynamics algorithm is differentiated with respect to the input parameters in order to form sensitivity equations. The algorithm makes use of techniques and notation from the theory of Lie groups and Lie algebras, which is reviewed briefly. One of the strengths of our formulation is the ability to easily differentiate the dynamics algorithm with respect to parameters of interest. We demonstrate one important use of our dynamics and sensitivity algorithms by using them to solve difficult optimal control problems for underactuated systems. The algorithms in this paper have been implemented in a software package named Cstorm (Computer simulation tool for the optimization of robot manipulators), which runs from within Matlab and Simulink. It can be downloaded from the website http://www.eng.uci.edu/∼bobrow/
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Ouyang, Tiancheng, Pan Wang e Haozhong Huang. "Cam profile optimization for the delivery system of an offset press". Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 231, n. 23 (17 agosto 2016): 4287–97. http://dx.doi.org/10.1177/0954406216665135.
Testo completoAbstract (sommario):
In this paper, a relatively new strategy known as unified optimization is applied to the cam profile optimization for the delivery system of an offset press by integrating the procedure of single objective optimization with ADAMS software. The proposed approach mainly consists of two parts that includes a single objective optimization procedure and a multibody dynamic model of cam–follower mechanism. For the procedure of single objective optimization, the design process starts from defining the follower acceleration profile by using a modified trapezoidal curve, then genetic algorithm is adopted to determine the evaluating indexes for the kinematic behavior of cam–follower mechanism in multiobjective optimization. Subsequently, sequential quadratic programming, which deals well with equality and inequality constrains, is selected as single objective optimized algorithm in this part. On the other hand, the dynamic simulation developed by ADAMS software is carried out to investigate the dynamic characteristics of cam–follower mechanism. Finally, an optimization cycle, also known as iterative process, is proposed to implement the procedure of single objective optimization and dynamic simulation alternately to improve the kinematic and dynamic characteristics of cam–follower mechanism fully. The cam profile optimization method presented in this paper provides a new tool for cam designers to avoid the undesirable impact and follower jump.
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Ondočko, Štefan, Jozef Svetlík, Rudolf Jánoš, Ján Semjon e Miroslav Dovica. "Calculation of Trusses System in MATLAB—Multibody". Applied Sciences 14, n. 20 (19 ottobre 2024): 9547. http://dx.doi.org/10.3390/app14209547.
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This article discusses the software tool (Simscape—Multibody program of MATLAB) primarily intended for dynamic and kinematic processes with practical applications in static calculations. Currently, there are few published scientific works utilizing this tool for tasks like basic static calculations of truss systems. We were interested in comparing the calculation using the tools we use in our work and research activities for theoretical calculation; the potential reliance on simulations in the future could help to avoid the necessity of complex theoretical calculations, which can be time-consuming and prone to errors. Despite the fact that the structure may appear simple, in practice, there may not always be time for a verification calculation in the theoretical field (proper model creation, inclusion of all conditions, etc.). The beam system is intentionally both externally and internally statically indeterminate. For this reason, it is logically necessary to also consider deformation conditions. The achieved results were interesting in terms of accuracy compared to SOLIDWORKS, which was used for computation verification. Through very simple optimization, we were able to further increase the calculation accuracy without complicating other parameters.
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D’Imperio, Simone, Teresa Maria Berruti, Chiara Gastaldi e Pietro Soccio. "Practical Design Guidelines for Topology Optimization of Flexible Mechanisms: A Comparison between Weakly Coupled Methods". Robotics 13, n. 4 (23 marzo 2024): 55. http://dx.doi.org/10.3390/robotics13040055.
Testo completoAbstract (sommario):
Industrial robots are complex systems, as they require the integration of several sub-assemblies to perform accurate operations. Moreover, they may experience remarkable dynamic actions due to high kinematic requirements, which are necessary to obtain reduced cycle times. The dynamic design of industrial robots can therefore be demanding, since the single structural component can induce an impact both in the design phase (development strategy and computational time) and at the machine level (global stiffness and natural frequencies). To this end, the present paper proposes first a topology optimization procedure based on the Equivalent Static Loads (ESL) method that integrates flexible multibody simulation outputs. The same procedure also foresees an intermediate static reduction to reduce and to precisely define the application points of the ESL. Secondly, an optimization procedure based on the Quasi-Static Loads (QSL) method integrating flexible multibody simulation outputs is proposed as well. The objective is to carry out a comparison between the two methods and consequently evaluate the benefits and drawbacks of the two. In the end, practical guidelines regarding the selection and application of the two methods are also provided to the reader.
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Bucchi, Francesco, e Basilio Lenzo. "Analytical Derivation and Analysis of Vertical and Lateral Installation Ratios for Swing Axle, McPherson and Double Wishbone Suspension Architectures". Actuators 11, n. 8 (9 agosto 2022): 229. http://dx.doi.org/10.3390/act11080229.
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In the context of suspension design, the installation ratio (or motion ratio) is a parameter that relates wheel movement with spring deflection, quite an important kinematic property of a suspension. Yet, no study in the literature provides a clear relationship between the installation ratio and the geometrical features of a suspension. This paper employs rigid body kinematics and appropriate geometrical schematics to fill such a gap. Analytical expressions of the installation ratio are derived for three suspension layouts: swing axle, McPherson, double wishbone. Key concepts such as instant center, roll center and camber gain are harnessed to provide insightful analyses for relevant case studies of suspension passenger cars. Among the key results, the typical assumption of a McPherson installation ratio close to 1 is supported by a formal demonstration, and the new concept of “lateral” installation ratio is introduced which, alongside the classical “vertical” installation ratio, further characterizes suspension motion. Numerical results obtained through a multibody software support the findings of this paper. In conclusion, this study provides valuable insights for suspension design engineers.
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Michaud, Benjamin, Sonia Duprey e Mickaël Begon. "Scapular kinematic reconstruction – segmental optimization, multibody optimization with open-loop or closed-loop chains: which one should be preferred?" International Biomechanics 4, n. 2 (3 novembre 2017): 86–94. http://dx.doi.org/10.1080/23335432.2017.1405741.
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Henriques, Diamantino, Ana P. Martins e Marta S. Carvalho. "Efficient 2D Neck Model for Simulation of the Whiplash Injury Mechanism". Bioengineering 11, n. 2 (29 gennaio 2024): 129. http://dx.doi.org/10.3390/bioengineering11020129.
Testo completoAbstract (sommario):
Whiplash injuries, mainly located in the neck, are one of the most common injuries resulting from road collisions. These injuries can be particularly challenging to detect, compromising the ability to monitor patients adequately. This work presents the development and validation of a computationally efficient model, called Efficient Neck Model—2D (ENM-2D), capable of simulating the whiplash injury mechanism. ENM-2D is a planar multibody model consisting of several bodies that model the head and neck with the same mass and inertia properties of a male occupant model in the 50th percentile. The damping and non-linear spring parameters of the kinematic joints were identified through a multiobjective optimization process, solved sequentially. The TNO-Human Body Model (TNO-HBM), a validated occupant model for rear impact, was simulated, and its responses were used as a reference for validation purposes. The root mean square (RMS) of the deviations of angular positions of the bodies were used as objective functions, starting from the bottom vertebra to the top, and ending in the head. The sequence was repeated until it converged, ending the optimization process. The identified ENM-2D model could simulate the whiplash injury mechanism kinematics and accurately determine the injury criteria associated with head and neck injuries. It had a relative deviation of 8.3% for the head injury criteria and was 12.5 times faster than the reference model.
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Geonea, Ionut, Cristian Copilusi, Sorin Dumitru, Alexandru Margine, Adrian Rosca e Daniela Tarnita. "A New Exoskeleton Prototype for Lower Limb Rehabilitation". Machines 11, n. 11 (30 ottobre 2023): 1000. http://dx.doi.org/10.3390/machines11111000.
Testo completoAbstract (sommario):
This paper presents a new solution for an exoskeleton robotic system that is used for locomotor assistance in people with locomotor disabilities. As novel features of the present research, a novel structural solution of a plane-parallel kinematic chain, intended to be used as the leg of an exoskeleton robot, is proposed. A virtual prototype is made, on the basis of which kinematic and dynamic studies are carried out using ADAMS software for the dynamic analysis of multibody systems. The dynamic simulation of the exoskeleton is performed in two simulation situations: walking on a horizontal plane, as well as the simulation of motion assistance when climbing stairs. Following this analysis, it is noted that the robotic system achieves angular variations in the hip and knee joints similar to that of a human subject. As a result, the constructive solution is feasible, and the next stage of the study is to realize an experimental prototype by the rapid prototyping technique. The kinematic elements of the exoskeleton are designed to provide structural strength, to be easily manufactured by 3D printing and to be easy to assemble. For this purpose, the structural optimization is performed with the finite element method to eliminate stress concentrators. Finally, an experimental prototype of the exoskeleton robot is manufactured and assembled, whose motion is analyzed using ultrafast-camera-based video analysis.
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Pan, Yongjun, Chao Zhang, Banghui Yin e Baohua Wang. "Fuzzy set based multi-objective optimization for eight-rod mechanism via sensitivity analysis". Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 233, n. 2 (8 dicembre 2017): 333–43. http://dx.doi.org/10.1177/0954407017743358.
Testo completoAbstract (sommario):
The wheel loader multi-rod mechanism working device, which can be considered as a rigid multibody system, is a crucial component for shoveling and loading material. The six-rod and eight-rod mechanisms are two popular working devices used in construction, mining and agriculture. However, the design of the eight-rod mechanism device has not received much more attention due to its emerging applications. In this paper, a fuzzy set based multi-objective optimization procedure for an eight-rod mechanism device is presented by taking advantage of design sensitivities. The sensitivity analysis is carried out to extract the several most relevant design variables so as to simplify the optimization problem. Furthermore, the fuzzy set theory is introduced to express each objective in terms of membership function, thus different objectives can be measured in the same dimension. As a result, the multi-objective optimization problem is converted into a single objective through the combined membership function. Finally, an eight-rod mechanism working device of a wheel loader is analyzed and optimized by using the proposed method. The results show that the optimal eight-rod mechanism can provide a better kinematic performance.
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Pan, Yongjun, e Liang Hou. "Lifting and parallel lifting optimization by using sensitivity and fuzzy set for an earthmoving mechanism". Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 231, n. 2 (11 agosto 2016): 192–203. http://dx.doi.org/10.1177/0954407016660454.
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Earthmoving equipment in motor graders, which can be considered to be complex multibody systems (MBSs), are critical components for earthwork, compaction and re-handling. They have not yet received much attention due to their unusual applications and complicated structures. In this paper, a comprehensive study of an earthmoving MBS, from the mechanism identification and sensitivity analysis to the multi-objective optimization, is presented. First, the earthmoving MBS is identified to be a six degrees-of-freedom spatial hybrid mechanism, where a three revolute-revolute-prismatic-spherical (RRPS) and one spherical subchain (so, RRPS-S) spatial parallel mechanism is the key subsystem, through the mechanism analysis and synthesis. An earthmoving virtual prototyping model is built according to the system topology and connectivity. The kinematic simulations are carried out by imposing corresponding driving functions. Afterwards, the sensitivity analysis is introduced to extract several most relevant design variables from the global ones. A multi-objective optimization process is carried out to improve working performance, where fuzzy sets are used to define different objectives. Results show that the optimal earthmoving mechanism provides better lifting and parallel lifting capabilities.
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Reddy, A. Sridhar, V. V. M. J. Satish Chembuly e V. V. S. Kesava Rao. "Modelling and Simulation of a Redundant Agricultural Manipulator with Virtual Prototyping". Journal of Robotics and Control (JRC) 4, n. 1 (8 marzo 2023): 83–94. http://dx.doi.org/10.18196/jrc.v4i1.17121.
Testo completoAbstract (sommario):
The development of autonomous robots for agricultural applications includes motion planning, fruit picking, and collision avoidance with surrounding environments, and these become challenging tasks. For harvesting applications, robust control of the manipulator is needed for the effective motion of the robot. Several combinations of Proportional(P)- Integrative(I)- Derivative(D) controllers are modelled and a simulation study was performed for trajectory tracking of a redundant manipulator in virtual agricultural environments. The article presents a comprehensive study on kinematic modelling and dynamic control of redundant manipulator for fruit-picking applications in virtual environments. The collisions with surrounding environment were eliminated using ‘bounding box technique’. The joint variables are obtained by constructing Inverse Kinematics (IK) problem and are determined using a classical optimization technique. Different controllers are modelled in the ‘Simulink’ environment and are tuned to generate error-free trajectory tracking during harvesting. The task space locations (TSLs) are considered as via-points, and joint variables at each TSLs are obtained by Sequential Quadratic Programming (SQP) technique. Joint-level trajectories are generated using Quintic and B-spline polynomials. For effective trajectory tracking, torque variations are controlled using the PID and Feedforward (FF) controller. The dynamic simulations of the robot manipulator are performed in Simscape Multibody software. Results show that the during the trajectory tracking of the manipulator, the Feed-forward controller performs best with Quintic polynomial trajectory.
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Saleh, Mohammed, Ayman Nada, Ahmed El-Betar e Ahmed El-Assal. "Computational Design Scheme for Wind Turbine Drive-Train Based on Lagrange Multipliers". Journal of Energy 2017 (2017): 1–16. http://dx.doi.org/10.1155/2017/4027834.
Testo completoAbstract (sommario):
The design optimization of wind turbines and their subsystems will make them competitive as an ideal alternative for energy. This paper proposed a design procedure for one of these subsystems, which is the Wind Turbine Drive-Train (WTDT). The design of the WTDT is based on the load assumptions and considered as the most significant parameter for increasing the efficiency of energy generation. In industry, these loads are supplemented by expert assumptions and manipulated to design the transmission elements. In contrary, in this work, the multibody system approach is used to estimate the static as well as dynamic loads based on the Lagrange multipliers. Lagrange multipliers are numerical parameters associated with the holonomic and nonholonomic constraints assigned in the drive-train model. The proposed scheme includes computational manipulations of kinematic constraints, mapping the generalized forces into Cartesian respective, and enactment of velocity-based constrains. Based on the dynamic model and the obtained forces, the design process of a planetary stage of WTDT is implemented with trade-off’s optimization in terms of gearing parameters. A wind turbine of 1.4 megawatts is introduced as an evaluation study of the proposed procedure, in which the main advantage is the systematic nature of designing complex systems in motion.
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Bourgain, Maxime, Christophe Sauret, Grégoire Prum, Laura Valdes-Tamayo, Olivier Rouillon, Patricia Thoreux e Philippe Rouch. "Effect of Horizontal Ground Reaction Forces during the Golf Swing: Implications for the Development of Technical Solutions of Golf Swing Analysis". Proceedings 49, n. 1 (15 giugno 2020): 45. http://dx.doi.org/10.3390/proceedings2020049045.
Testo completoAbstract (sommario):
The swing is a key movement for golf. Its in-field performance could be estimated by embedded technologies, but often only vertical ground reaction forces (VGRF) are estimated. However, as the swing plane is inclined, horizontal ground reaction forces (HGRF) are expected to contribute to the increase of the club angular velocity. Thus, this study aimed at investigating the role of the HGRF during the golf swing. Twenty-eight golf players were recruited and performed 10 swings with their own driver club, in a motion analysis laboratory, equipped with a full body marker set. Ground reaction forces (GRF) were measured with force-plates. A multibody kinematic optimization was performed with a full body model to estimate the instantaneous location of the golfer’s center of mass (CoM). Moments created by the GRF at the CoM were investigated. Results showed that horizontal forces should not be neglected regarding to VGRF because of their lever arm. Analyzing golf swing with only VGRF appeared not enough and further technological developments are still needed to ecologically measure other components.
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Hao, Tianyi, Zhixin Liu e Hai Liu. "Kinematics Bionic Concept Structure Design and Optimization of Vehicle Crash Dummy’s Knee Joint: Bionics and Biomechanics Applied in Collision Safety of Cars". Applied Bionics and Biomechanics 2023 (3 maggio 2023): 1–12. http://dx.doi.org/10.1155/2023/6621850.
Testo completoAbstract (sommario):
The structural bionicism of the knee joint of an automobile crash dummy is an important factor affecting the accuracy of the dummy’s knee displacement and knee flexion angle measurements in automobile crash tests. This study focused mainly on the optimization of the bionic structure of the knee joint of an automobile crash dummy to ensure that the dummy has a kinematic response closer to that of the knee joint of a real human. Forty sets of high-speed photographic images of the sphyrion were acquired by performing a trajectory-measurement test at the lower tibial point. Subsequently, the high-flexion motion trajectory of the knee joint was obtained by solving vector equations and by multicurve fitting. This trajectory, combined with the bionic structure design method, optimized the structure of the existing dummy’s knee joint. Thereby, its motion can be altered from a fixed-axis rotation to a non-fixed-axis curve motion close to how the human tibial plateau rotates around the femoral condyle. This increases the degrees of freedom of the dummy’s knee joint from two to three. The knee joint structures before and after the optimization were simulated kinematically using a multibody dynamics method. The results showed that the peak of the motion trajectory deviation of the optimized sphyrion decreased from 3.7% to 1.9%, and the average deviation decreased from 2.0% to 0.2%. This indicates that the structural optimization scheme improved the motion bionics of the crash dummy’s knee joint.
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Racz, Sever-Gabriel, Mihai Crenganiș, Radu-Eugen Breaz, Alexandru Bârsan, Claudia-Emilia Gîrjob, Cristina-Maria Biriș e Melania Tera. "Integrating Trajectory Planning with Kinematic Analysis and Joint Torques Estimation for an Industrial Robot Used in Incremental Forming Operations". Machines 10, n. 7 (30 giugno 2022): 531. http://dx.doi.org/10.3390/machines10070531.
Testo completoAbstract (sommario):
Robot manufacturing involves continuous path control, which is now available for both robotic controllers and CAM software packages. However, CAM solutions are focused on generating the code for the robotic structure to follow the toolpath, without taking into consideration the dynamics and energy consumption. In this study, robot incremental forming was considered as the manufacturing process, and a simulation model, based upon Matlab-Simulink Simscape Multibody technology, was developed. The proposed model was fed with the trajectory information generated by the CAM program, and using an inverse kinematics function, it was able to generate the commands to drive the robotic structure on the technological toolpaths. The model was also used to study the dynamic behavior of the robot; external experimental data from a 3D force sensor were fed to the model to include the influence of the technological forces which appeared during the incremental forming process. Thus, using the proposed model in conjunction with the external CAM software, the influence of the workpiece position upon the joint torques could be estimated, opening the way for future optimization. The shortcomings of the model, mainly involving inaccurate information with regard to the physical properties of the robotic structure, were addressed by subtracting the dry-run joint torques from those obtained from the technological process.
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Yao, Di, Philipp Ulbricht, Stefan Tonutti, Kay Büttner e Prokop Günther. "A novel approach for experimental identification of vehicle dynamic parameters". Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 234, n. 10-11 (21 aprile 2020): 2634–48. http://dx.doi.org/10.1177/0954407020908724.
Testo completoAbstract (sommario):
Pervasive applications of the vehicle simulation technology are a powerful motivation for the development of modern automobile industry. As basic parameters of road vehicle, vehicle dynamic parameters can significantly influence the ride comfort and dynamics of vehicle, and therefore have to be calculated accurately to obtain reliable vehicle simulation results. Aiming to develop a general solution, which is applicable to diverse test rigs with different mechanisms, a novel model-based parameter identification approach using optimized excitation trajectory is proposed in this paper to identify the vehicle dynamic parameters precisely and efficiently. The proposed approach is first verified against a virtual test rig using a universal mechanism. The simulation verification consists of four sections: (a) kinematic analysis, including the analysis of forward/inverse kinematic and singularity architecture; (b) dynamic modeling, in which three kinds of dynamic modeling method are used to derive the dynamic models for parameter identification; (c) trajectory optimization, which aims to search for the optimal trajectory to minimize the sensitivity of parameter identification to measurement noise; and (d) multibody simulation, by which vehicle dynamic parameters are identified based on the virtual test rig in the simulation environment. In addition to the simulation verification, the proposed parameter identification approach is applied to the real test rig (vehicle inertia measuring machine) in laboratory subsequently. Despite the mechanism difference between the virtual test rig and vehicle inertia measuring machine, this approach has shown an excellent portability. The experimental results indicate that the proposed parameter identification approach can effectively identify the vehicle dynamic parameters without a high requirement of movement accuracy.
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Géradin, Michel. "Dynamics of a flexible body: a two-field formulation". Multibody System Dynamics 54, n. 1 (18 ottobre 2021): 1–29. http://dx.doi.org/10.1007/s11044-021-09801-0.
Testo completoAbstract (sommario):
AbstractA two-field formulation of the nonlinear dynamics of an elastic body is presented in which positions/orientations and the resulting velocity field are treated as independent. Combining a nonclassical description of elastic velocity that includes the convection velocity due to elastic deformation with floating reference axes minimizing the relative kinetic energy due to elastic deformation provides a fully uncoupled expression of kinetic energy. A transformation inspired by the classical Legendre transformation concept is introduced to develop the motion equations in canonical form. Finite element discretization is achieved using the same shape function sets for elastic displacements and velocities. Specific attention is brought to the discretization of the gyroscopic forces induced by elastic deformation. A model reduction strategy to construct superelement models suitable for flexible multibody dynamics applications is proposed, which fulfills the essential condition of orthogonality between a rigid body and elastic motions. The problem of expressing kinematic connections at superelement boundaries is briefly addressed. Two academic examples have been developed to illustrate some of the concepts presented.
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Li, Zhang, e Yuegang Tan. "Trotting Motion of the Quadruped Model with Two Spinal Joints and Its Dynamics Features". Journal of Robotics 2020 (22 giugno 2020): 1–14. http://dx.doi.org/10.1155/2020/3156540.
Testo completoAbstract (sommario):
The spine plays important roles in the quadruped locomotion. To investigate the effects of the spine on the quadruped trotting motion, firstly, a sagittal passive model is proposed which contains four massless springy legs and two passive spinal joints. To generate the trotting gait of the model, the multibody hybrid dynamics model is established based on the defined events. The combination of optimization tools is used to find the suitable solution space in which the model can maintain a periodic motion. It reveals that the quadruped trotting motion results from the coordinated features of the spine and the legs. By comparing the model with the rigid body, it is proven that the spinal joints can reduce the effect of the ground reaction forces on the body in a special velocity range. Then, a hybrid controller whose objective is to maintain the kinematic coordination between the spinal joints is applied and it replaces the passive spinal joints, and the results prove that it can make the model achieve a stable periodic motion. Finally, the prototype of the quadruped robot with two spinal joints based on the model is established and its trotting motion is achieved successfully. The experiment results also indicate the compliant effect of the spine on the motion performance. Consequently, the effects of the spine at trotting gait are helpful to guide the development of the quadruped robots.
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Terzini, Mara, Luca Mossa, Cristina Bignardi, Piero Costa, Alberto Audenino, Aldo Vezzoni e Elisabetta Zanetti. "A structural numerical model for the optimization of double pelvic osteotomy in the early treatment of canine hip dysplasia". Veterinary and Comparative Orthopaedics and Traumatology 30, n. 04 (2017): 256–64. http://dx.doi.org/10.3415/vcot-16-05-0065.
Testo completoAbstract (sommario):
SummaryBackground: Double pelvic osteotomy (DPO) planning is usually performed by hip palpation, and on radiographic images which give a poor representation of the complex three-dimensional manoeuvre required during surgery. Furthermore, bone strains which play a crucial role cannot be foreseen.Objective: To support surgeons and designers with biomechanical guidelines through a virtual model that would provide bone stress and strain, required moments, and three-dimensional measurements.Methods: A multibody numerical model for kinematic analyses has been coupled to a finite element model for stress/strain analysis on deformable bodies. The model was parametrized by the fixation plate angle, the iliac osteotomy angle, and the plate offset in ventro-dorsal direction. Model outputs were: acetabular ventro-version (VV) and lateralization (L), Norberg (NA) and dorsal acetabular rim (DAR) angles, the percentage of acetabular coverage (PC), the peak bone stress, and moments required to deform the pelvis.Results: Over 150 combinations of cited parameters and their respective outcome were analysed. Curves reporting NA and PC versus VV were traced for the given patient. The optimal VV range in relation to NA and PC limits was established. The 25° DPO plate results were the most similar to 20° TPO. The output L grew for positive iliac osteotomy inclinations. The 15° DPO plate was critical in relation to DAR, while very large VV could lead to bone failure.Clinical significance: Structural models can be a support to the study and optimization of DPO as they allow for foreseeing geometrical and structural outcomes of surgical choices.ORCID iDALA: http://orcid.org/0000-0002-4877-3630AV: http://orcid.org/0000-0003-2837-7822CB: http://orcid.org/0000-0002-7065-2552EZ: http://orcid.org/0000-0003-4121-6126MT: http://orcid.org/0000-0002-5699-6009
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Llopis-Albert, Carlos, Francisco Rubio, Carlos Devece e Dayanis García-Hurtado. "Digital Twin-Based Approach for a Multi-Objective Optimal Design of Wind Turbine Gearboxes". Mathematics 12, n. 9 (1 maggio 2024): 1383. http://dx.doi.org/10.3390/math12091383.
Testo completoAbstract (sommario):
Wind turbines (WT) are a clean renewable energy source that have gained popularity in recent years. Gearboxes are complex, expensive, and critical components of WT, which are subject to high maintenance costs and several stresses, including high loads and harsh environments, that can lead to failure with significant downtime and financial losses. This paper focuses on the development of a digital twin-based approach for the modelling and simulation of WT gearboxes with the aim to improve their design, diagnosis, operation, and maintenance by providing insights into their behavior under different operating conditions. Powerful commercial computer-aided design tools (CAD) and computer-aided engineering (CAE) software are embedded into a computationally efficient multi-objective optimization framework (modeFrontier) with the purpose of maximizing the power density, compactness, performance, and reliability of the WT gearbox. High-fidelity models are used to minimize the WT weight, volume, and maximum stresses and strains achieved without compromising its efficiency. The 3D CAD model of the WT gearbox is carried out using SolidWorks (version 2023 SP5.0), the Finite Element Analysis (FEA) is used to obtain the stresses and strains, fields are modelled using Ansys Workbench (version 2024R1), while the multibody kinematic and dynamic system is analyzed using Adams Machinery (version 2023.3, Hexagon). The method has been successfully applied to different case studies to find the optimal design and analyze the performance of the WT gearboxes. The simulation results can be used to determine safety factors, predict fatigue life, identify potential failure modes, and extend service life and reliability, thereby ensuring proper operation over its lifetime and reducing maintenance costs.
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Yu, Xinxin, Javier F. Aceituno, Emil Kurvinen, Marko K. Matikainen, Pasi Korkealaakso, Asko Rouvinen, Dezhi Jiang, José L. Escalona e Aki Mikkola. "Comparison of numerical and computational aspects between two constraint-based contact methods in the description of wheel/rail contacts". Multibody System Dynamics 54, n. 3 (24 gennaio 2022): 303–44. http://dx.doi.org/10.1007/s11044-022-09811-6.
Testo completoAbstract (sommario):
AbstractThe numerical and computation aspects of the Knife-edge Equivalent Contact (KEC) constraint and lookup table (LUT) methods are compared in this paper. The LUT method implementation uses a penetration-based elastic contact model for the flange and a constraint-based formulation at the wheel tread. For the KEC method, where an infinitely narrow rail contacts an equivalent wheel, regularization of the tread-flange transition is adopted to simultaneously account for tread and flange contacts using constraints. A comparison between the two methods is carried out using well-known numerical integrators to show the applicability and limitations of both methods.Two fixed-step-size integrators, the explicit Runge–Kutta (RK4) and the predictor–corrector Adam–Bashforth–Moulton (ABM) methods, and two variable-step-size Matlab built-in function integrators, the explicit $ode45$ o d e 45 and implicit $ode15s$ o d e 15 s , were applied to get the numerical solutions to the dynamic problems and study the relative numerical performance of the two contact description methods. To complete the railway vehicle model, both contact methods were implemented for the multibody model of a benchmark railway vehicle (the Manchester wagon 1). Numerical results were obtained for different railway tracks with and without irregularities. Profiles of the S1002 wheel and LB-140-Area rail, which demonstrate the two-point contact phenomenon, were considered. Both methods were implemented in Matlab and validated against commercial simulation software. The kinematic results for both approaches show good agreement, but the KEC method was up to 20% more efficient than the LUT method regardless of integrator used.
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Ebenbichler, Maximilian, Dieter Heinrich, Maurice Mohr, Ryo Ueno e Robert Eberle. "Coupling a finite element knee model with musculoskeletal multibody simulations. A case study of ACL force during a change-of-direction movement before and after injury prevention training". Current Issues in Sport Science (CISS) 9, n. 4 (23 settembre 2024): 004. http://dx.doi.org/10.36950/2024.4ciss004.
Testo completoAbstract (sommario):
Introduction & Purpose Change of direction (COD) movements are a common cause of injuries to the anterior cruciate ligament (ACL), especially in sports such as soccer, basketball, handball (Agel et al., 2016). In Mohr et al., (2024) an 8-week injury prevention training program including COD technique training was investigated. The movements during COD were recorded in an experimental setup with a marker-based system before and after the training program. While Mohr and colleagues observed training effects on the COD movement strategy, it remains unknown whether the ACL forces are actually reduced by the training program. The purpose of this project was to 1) develop a simulation-based approach to estimate ACL forces during COD movements using musculoskeletal simulations (OpenSim) and finite element (FE) knee simulations, and 2) use existing kinematics from a COD movement of one athlete before and after the 8-week injury prevention training program to investigate training effects on ACL force (Mohr et al., 2024). Methods The model OKS008 from the publicly-available collection of Open Knee(s) (OKS) FE models (2nd generation) of the Cleveland Clinic (Chokhandre et al., 2023) was implemented in the FE software Abaqus CAE. In the original OKS008 model (Chokhandre et al., 2023) material parameters and pre-strains were taken from literature. However, the pre-strain of the ligaments is very individual (Lahkar et al., 2021). Therefore, in this study, the pre-strain of the ligaments and four material parameters of the OKS008 model were fit to in vitro kinetic testing data, using an optimization algorithm (interior-point algorithm). The kinetic data from in-vitro tests is available alongside with the OKS knee models, for which all donor knees were mechanically tested during passive flexion experiments (Chokhandre et al., 2023). The optimization was solved based on about 550 FE simulations over the course of one month (AMD Ryzen threadripper 3960 x 24-core processor x 48, 35 cores were used). The effect of the knee kinematics from Mohr and colleagues (2024) on the loading of the anterior cruciate ligament (ACL) was then investigated with the optimized FE knee model in a post-processing step. Inverse kinematics in OpenSim was used to determine the 3D knee joint kinematics of one athlete during a maximum-speed 135° COD movement before and after the injury prevention training program. This athlete was selected because after the 8-week injury prevention training program, he showed a significant reduction in maximum knee adduction moment. The run-up velocity of the athlete on the COD was 3.97 m/s before the training program (baseline) and 4.09 m/s after the training program (follow-up). To simulate the COD movements in Abaqus, the FE knee model was driven by the measured knee kinematics of the COD, where the secondary kinematics (knee adduction and internal rotation) of the OpenSim model were added to the FE model’s secondary kinematics during passive flexion. The resulting force on the ACL was calculated by a free body cut in Abaqus CAE. Results The pre-strain optimized FE knee model closely reproduced the secondary kinematics (abduction, internal rotation) of the donor knee during passive flexion (mean error of 2.1687° before vs. 0.5799° after optimization). The athlete’s maximum ACL force during the COD before the training program was 457 N, while after the training program a reduction in ACL force during the COD to 246 N was observed (46% reduction). The ACL force during the COD before and after the injury prevention training program is shown in Figure 1. Discussion A publicly available FE knee model was successfully optimized based on cadaveric mechanical testing data and implemented into a simulation-based approach to estimate ACL force. The plausibility of the model was checked by a mesh study and comparison with cadaver studies done in Wascher et al. (1993) and Hosseini Nasab et al. (2016). The timing of peak ACL force during a simulated COD movement, between 50 ms and 100 ms after initial contact, is physiologically plausible given that ACL injuries during CODs typically occur around 50 ms after initial contact (Krosshaug et al., 2007). The pre-strain optimization showed that it is necessary to estimate material parameters, e.g. ligament pre-strain, individually for each model to obtain realistic mechanical behaviour. The case study demonstrated a reduction in ACL force during a COD by 46% following an injury prevention training program. The existing kinematic data from Mohr and colleagues (2024) show that the analyzed athlete performed the COD with decreased knee internal rotation and abduction after the 8-week injury prevention training. It is assumed that the ACL force was reduced due to the lower internal rotation and abduction. Figure 1 show further interesting observations that warrant investigation, e.g. the time-shifted peak ACL force following training. This will be done in future studies including more athletes. Importantly, ACL forces during change of direction (COD) were calculated by applying only rotational kinematics to the FE model. The next step will be to implement joint reaction forces (JRF) into the FE simulations because they would have an effect on the ACL force (Esrafilian et al., 2022). It is therefore advisable to include the JRF in the subsequent simulations in order to obtain more physiologically relevant results. Conclusion We developed a FE simulation model in Abaqus CAE of the OKS008 knee to estimate and compare ACL forces based on the existing kinematics of a COD movement. However, individual material parameter estimation is required for each model. The material parameter estimation increases the replicability of the specimen specific mechanical cadaver testing. This is an improvement to the original OKS008 model. For the one analyzed athlete, after the 8-week injury prevention exercise program (Mohr et al., 2024) the ACL force caused by rotational kinematics of a COD is less than before the exercise program. The maximum ACL force during COD is reduced by 46% after the exercise program. References Agel, J., Rockwood, T., & Klossner, D. (2016). Collegiate ACL injury rates across 15 sports: National collegiate athletic association injury surveillance system data update (2004-2005 through 2012-2013). Clinical Journal of Sport Medicine, 26(6), 518-523. https://doi.org/10.1097/JSM.0000000000000290 Chokhandre, S., Schwartz, A., Klonowski, E., Landis, B., & Erdemir, A. (2023). Open knee(s): A free and open source library of specimen-specific models and related digital assets for finite element analysis of the knee joint. Annals of Biomedical Engineering, 51, 10-23. https://doi.org/10.1007/s10439-022-03074-0 Esrafilian, A., Stenroth, L., Mononen, M. E., Vartiainen, P., Tanska, P., Karjalainen, P. A., Suomalainen, J.-S., Arokoski, J. P. A., Saxby, D. J., Lloyd, D. G., & Korhonen, R. K. (2022). Toward tailored rehabilitation by implementation of a novel musculoskeletal finite element analysis pipeline. IEEE Transactions on Neural Systems and Rehabilitation Engineering, 30, 789-802. https://doi.org/10.1109/TNSRE.2022.3159685 Hosseini Nasab, S. H., List, R., Oberhofer, K., Fucentese, S. F., Snedeker, J. G., & Taylor, W. R. (2016). Loading patterns of the posterior cruciate ligament in the healthy knee: A systematic review. PLoS One, 11(11), Article e0167106. https://doi.org/10.1371/journal.pone.0167106 Krosshaug, T., Nakamae, A., Boden, B. P., Engebretsen, L., Smith, G., Slauterbeck, J. R., Hewett, T. E., & Bahr, R. (2007). Mechanisms of anterior cruciate ligament injury in basketball: Video analysis of 39 cases. The American Journal of Sports Medicine, 35(3), 359-67. https://doi.org/10.1177/0363546506293899 Lahkar, B. K., Rohan, P.-Y., Pillet, H., Thoreux, P., & Skalli, W. (2021). Development and evaluation of a new procedure for subject-specific tensioning of finite element knee ligaments. Computer Methods in Biomechanics and Biomedical Engineering, 24(11), 1195-1205. https://doi.org/10.1080/10255842.2020.1870220 Mohr, M., Federolf, P., Heinrich, D., Nitschke, M., Raschner, C., Scharbert, J., & Koelewijn, A. D. (2024). An 8-week injury prevention exercise program combined with change-of-direction technique training limits movement patterns associated with anterior cruciate ligament injury risk. Scientific Reports, 14, Article 3115. https://doi.org/10.1038/s41598-024-53640-w Wascher, D. C., Markolf, K. L., Shapiro, M. S., & Finerman, G. A. (1993). Direct in vitro measurement of forces in the cruciate ligaments. Part I: The effect of multiplane loading in the intact knee. The Journal of Bone and Joint Surgery, 75(3), 377-386. https://doi.org/10.2106/00004623-199303000-00009
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Ruggiero, Alessandro, e Alessandro Sicilia. "A Novel Explicit Analytical Multibody Approach for the Analysis of Upper Limb Dynamics and Joint Reactions Calculation Considering Muscle Wrapping". Applied Sciences 10, n. 21 (2 novembre 2020): 7760. http://dx.doi.org/10.3390/app10217760.
Testo completoAbstract (sommario):
The aim of this paper is to present an explicit analytical biomechanical multibody procedure able to be implemented in the solution of the musculoskeletal systems inverse dynamics problems. The model is proposed in formal multibody analysis and implemented in the Matlab numerical environment. It is based on the constraint kinematical behaviour analysis and considers both linear muscle actuators and curved ones, by calculating the geodesic muscle path over wrapping surfaces fixed to the bodies. The model includes the Hill muscle approach in order to evaluate both the contractile elements’ actions and the passive ones. With the aim to have a first validation, the model was applied to the dynamical analysis of the “arm26” OpenSim model, an upper limb subjected to external forces of gravity and to known kinematics. The comparison of results shows interesting matching in terms of kinematical analysis, driving forces, muscles’ activations and joint reactions, proving the reliability of the proposed approach in all cases in which it is necessary to achieve in-silico explicit determinations of the upper limb dynamics and joint reactions (i.e., in joint tribological optimization).
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Esposito, Daniele, Jessica Centracchio, Emilio Andreozzi, Sergio Savino, Gaetano D. Gargiulo, Ganesh R. Naik e Paolo Bifulco. "Design of a 3D-Printed Hand Exoskeleton Based on Force-Myography Control for Assistance and Rehabilitation". Machines 10, n. 1 (13 gennaio 2022): 57. http://dx.doi.org/10.3390/machines10010057.
Testo completoAbstract (sommario):
Voluntary hand movements are usually impaired after a cerebral stroke, affecting millions of people per year worldwide. Recently, the use of hand exoskeletons for assistance and motor rehabilitation has become increasingly widespread. This study presents a novel hand exoskeleton, designed to be low cost, wearable, easily adaptable and suitable for home use. Most of the components of the exoskeleton are 3D printed, allowing for easy replication, customization and maintenance at a low cost. A strongly underactuated mechanical system allows one to synergically move the four fingers by means of a single actuator through a rigid transmission, while the thumb is kept in an adduction or abduction position. The exoskeleton’s ability to extend a typical hypertonic paretic hand of stroke patients was firstly tested using the SimScape Multibody simulation environment; this helped in the choice of a proper electric actuator. Force-myography was used instead of the standard electromyography to voluntarily control the exoskeleton with more simplicity. The user can activate the flexion/extension of the exoskeleton by a weak contraction of two antagonist muscles. A symmetrical master–slave motion strategy (i.e., the paretic hand motion is activated by the healthy hand) is also available for patients with severe muscle atrophy. An inexpensive microcontroller board was used to implement the electronic control of the exoskeleton and provide feedback to the user. The entire exoskeleton including batteries can be worn on the patient’s arm. The ability to provide a fluid and safe grip, like that of a healthy hand, was verified through kinematic analyses obtained by processing high-framerate videos. The trajectories described by the phalanges of the natural and the exoskeleton finger were compared by means of cross-correlation coefficients; a similarity of about 80% was found. The time required for both closing and opening of the hand exoskeleton was about 0.9 s. A rigid cylindric handlebar containing a load cell measured an average power grasp force of 94.61 N, enough to assist the user in performing most of the activities of daily living. The exoskeleton can be used as an aid and to promote motor function recovery during patient’s neurorehabilitation therapy.
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Begon, Mickaël, Colombe Bélaise, Alexandre Naaim, Arne Lundberg e Laurence Chèze. "Multibody kinematics optimization with marker projection improves the accuracy of the humerus rotational kinematics". Journal of Biomechanics 62 (settembre 2017): 117–23. http://dx.doi.org/10.1016/j.jbiomech.2016.09.046.
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Burkhalter, Drew. "Simulation-Driven Design of a Portable Basketball Hoop System". Proceedings 49, n. 1 (15 giugno 2020): 131. http://dx.doi.org/10.3390/proceedings2020049131.
Testo completoAbstract (sommario):
A simulation-driven design process is proven to generate improved, more robust, and cost-effective designs within a shorter design cycle. Incorporating simulation and optimization early in the design cycle helps shape the concept designs so fewer iterations and rework are necessary as the design matures. For this case study, a portable basketball hoop system is chosen for several reasons. This is a product that is common in everyday life, easily understood, and has several design challenges. To achieve the various design goals for this product, several optimization tools and simulation disciplines are coupled: multibody simulation to determine the kinematics and dynamics; finite element analysis to find displacements and stresses caused by external loads; topology optimization to define the essential structure to efficiently support the loads the product endures throughout its life cycle; and finally, multimodel optimization to consider all the loads when the structure is in several configurations during the optimization process.
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Wojtusch, Janis, Jurgen Kunz e Oskar von Stryk. "MBSlib–An Efficient Multibody Systems Library for Kinematics and Dynamics Simulation, Optimization and Sensitivity Analysis". IEEE Robotics and Automation Letters 1, n. 2 (luglio 2016): 954–60. http://dx.doi.org/10.1109/lra.2016.2527830.
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Pacher, Léonie, Nicolas Vignais, Christian Chatellier, Rodolphe Vauzelle e Laetitia Fradet. "The contribution of multibody optimization when using inertial measurement units to compute lower-body kinematics". Medical Engineering & Physics 111 (gennaio 2023): 103927. http://dx.doi.org/10.1016/j.medengphy.2022.103927.
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Dai, Wei, Yongjun Pan, Chuan Min, Sheng-Peng Zhang e Jian Zhao. "Real-Time Modeling of Vehicle’s Longitudinal-Vertical Dynamics in ADAS Applications". Actuators 11, n. 12 (16 dicembre 2022): 378. http://dx.doi.org/10.3390/act11120378.
Testo completoAbstract (sommario):
The selection of an appropriate method for modeling vehicle dynamics heavily depends on the application. Due to the absence of human intervention, the demand for an accurate and real-time model of vehicle dynamics for intelligent control increases for autonomous vehicles. This paper develops a multibody vehicle model for longitudinal-vertical dynamics applicable to advanced driver assistance (ADAS) applications. The dynamic properties of the chassis, suspension, and tires are considered and modeled, which results in accurate vehicle dynamics and states. Unlike the vehicle dynamics models built into commercial software packages, such as ADAMS and CarSim, the proposed nonlinear dynamics model poses the equations of motion using a subset of relative coordinates. Therefore, the real-time simulation is conducted to improve riding performance and transportation safety. First, a vehicle system is modeled using a semi-recursive multibody dynamics formulation, and the vehicle kinematics and dynamics are accurately calculated using the system tree-topology. Second, a fork-arm removal technique based on the rod-removal technique is proposed to reduce the number of bodies, relative coordinates, and equations constrained by loop-closure. This increase the computational efficiency even further. Third, the dynamic simulations of the vehicle are performed on bumpy and sloping roads. The accuracy and efficiency of the numerical results are compared to the reference data. The comparative results demonstrate that the proposed vehicle model is effective. This efficient model can be utilized for the intelligent control of vehicle ADAS applications, such as forward collision avoidance, adaptive cruise control, and platooning.
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Hybois, S., A. Lombart, P. Puchaud, J. Bascou, F. Lavaste, H. Pillet e C. Sauret. "Effects of ellipsoid parameters on scapula motion during manual wheelchair propulsion based on multibody kinematics optimization. A preliminary study". Computer Methods in Biomechanics and Biomedical Engineering 20, sup1 (27 ottobre 2017): S107—S108. http://dx.doi.org/10.1080/10255842.2017.1382884.
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Pappalardo, Carmine Maria, Marco Del Giudice, Emanuele Baldassarre Oliva, Littorino Stieven e Alessandro Naddeo. "Computer-Aided Design, Multibody Dynamic Modeling, and Motion Control Analysis of a Quadcopter System for Delivery Applications". Machines 11, n. 4 (8 aprile 2023): 464. http://dx.doi.org/10.3390/machines11040464.
Testo completoAbstract (sommario):
This paper elaborates on the modeling and control of an Unmanned Aerial Vehicle (UAV) for delivery purposes, thereby integrating computer-aided design, multibody dynamic modeling, and motion control analysis in a unified framework. The UAV system designed in this study and utilized for item delivery has a quadcopter structure composed of four arms connected to a central trunk. In this investigation, the proposed design of the delivery drone is systematically modeled employing the multibody approach, while SIMSCAPE MULTIBODY is the software used for performing the dynamic analysis and for devising the final design of the control system. To this end, starting from the CAD model designed using SOLIDWORKS, the control system of the quadcopter is developed by performing dynamic simulations in the MATLAB/SIMULINK environment. Additionally, another fundamental contribution of this paper is the analytical derivation of the nonlinear set of algebraic constraint equations peculiar to the present multibody system, which characterizes the kinematics of the delivery drone and describes the relative angular velocity imposed between two rigid bodies as nonholonomic constraints. Furthermore, as discussed in detail in this paper, the choice of the propulsion system and the design of the individual components heavily depends on the structural and functional needs of the UAV under study. On the other hand, the control system devised in this work is based on cascaded Proportional-Integral-Derivative (PID) controllers, which are suitable for achieving different maneuvers that are fundamental for the motion control of the delivery drone. Therefore, the final performance of the UAV system is a consequence of the regulation of the feedback parameters that characterize the PID controllers. In this respect, the paper presents the refining of the parameters characterizing the PID controllers by using both an internal MATLAB tool, which automatically tunes the controller gains of single-input single-output systems, and by observing the resulting transient behavior of the UAV system, which is obtained through extensive dynamical simulations. The set of numerical results found in this investigation demonstrates the high performance of the dynamical behavior of the UAV system designed in this work.
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Pawar, Prathmesh, e Prof Gayatri S. Patil. "Design and Analysis of Driver Seat Suspension System". International Journal for Research in Applied Science and Engineering Technology 11, n. 6 (30 giugno 2023): 1470–76. http://dx.doi.org/10.22214/ijraset.2023.53849.
Testo completoAbstract (sommario):
Abstract: Over the years, the vehicle driver has endured a great deal of agony and anguish as a result of poor road conditions or lengthier travel lengths that they must complete within a certain time limit. It is a misery to them that the standard or budget vehicles do not feature a good suspension system for their wellbeing. This research article demonstrates a unique design of scissor seat suspension for vehicles, as well as models for manufacturing and testing the system to eliminate low-frequency and high-amplitude vibrations that might cause health problems for vehicle drivers or passengers. Although scissor seat suspension is frequently utilized in commercial vehicles to reduce interior vibrations, a common optimization difficulty emerges because designs often involve a compromise between seat acceleration and suspension travel. The stiffness and damping characteristics of the scissor seat suspension are also investigated, and a simplified model of the scissor seat suspension is presented. The effect of damping force and mass on a human is investigated in preparation for future design and testing. The ideal vertical stiffness damping response is then cascaded into a performance-oriented model, and the design parameters are optimized with a multibody kinematics model focused on the scissor seat suspension structure.
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Feng, Yinnan, Juan Wu, Chenhao Guo e Baoguo Lin. "Numerical Simulation and Experiment on Excavating Resistance of an Electric Cable Shovel Based on EDEM-RecurDyn Bidirectional Coupling". Machines 10, n. 12 (12 dicembre 2022): 1203. http://dx.doi.org/10.3390/machines10121203.
Testo completoAbstract (sommario):
The electric cable shovel (ECS) is one of the core pieces of equipment used in open-pit mining, and the prediction of its excavating resistance is the basis and focus of optimization design, such as excavation trajectory planning and structure optimization of the ECS. Aiming to predict the excavating resistance of an ECS, a computer simulation method for the excavating resistance based on EDEM-RecurDyn bidirectional coupling simulation is proposed herein. Taking the China-made WK series ECS as the research object, a 1/30 scale model of the ECS was set up, a prototype model test bench of the ECS was built, and the kinematics solution and force analysis of the excavating process were carried out. According to the actual excavation conditions and excavating process of the ECS, a discrete element model of the material stack and a multibody dynamics model of the ECS prototype were established. The EDEM-RecurDyn bidirectional coupling simulation of the excavating process were realized using interface technology, and the excavating resistance levels under different speed combinations and different material repose angles were simulated and analyzed. In order to verify the accuracy of the simulation results, the feasibility and reliability of the EDEM-RecurDyn bidirectional coupling simulation were verified by physical experiments. The results show that the simulated excavating resistance is basically consistent with the excavating resistance measured in the experiment in terms of peak value and change trend, which verifies the feasibility and reliability of the EDEM-RecurDyn bidirectional coupling simulation to study the excavating resistance of an ECS.
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Racz, Sever-Gabriel, Mihai Crenganiș, Radu-Eugen Breaz, Adrian Maroșan, Alexandru Bârsan, Claudia-Emilia Gîrjob, Cristina-Maria Biriș e Melania Tera. "Mobile Robots—AHP-Based Actuation Solution Selection and Comparison between Mecanum Wheel Drive and Differential Drive with Regard to Dynamic Loads". Machines 10, n. 10 (1 ottobre 2022): 886. http://dx.doi.org/10.3390/machines10100886.
Testo completoAbstract (sommario):
Mobile robots are increasingly used in industrial applications. There are many constructive solutions for mobile robots using various variants of actuation and control. The proposed work presents a low-cost variant of a mobile robot equipped with Mecanum wheels, which uses brushed DC motors, controlled by the PWM method as the actuation solution. In the first part, a multicriteria analysis based on the AHP method was performed for the selection of the actuation solution. Then, using the software tools Simscape Multibody, Matlab, and Simulink, models were developed that allowed the simulation of the operation of the proposed robot, based both on its kinematics and dynamics. Using these models, both the Mecanum wheel drive version and the differential drive version were studied by means of simulation. The simulations mainly aimed at identifying the way the currents vary through the wheel drive motors, in order to find methods to reduce them. The values obtained by the simulation were later compared with those obtained experimentally, and the corresponding conclusions with regard to the accuracy of the models were drawn.
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Remus, Robin, Andreas Lipphaus, Marc Neumann e Beate Bender. "Calibration and validation of a novel hybrid model of the lumbosacral spine in ArtiSynth–The passive structures". PLOS ONE 16, n. 4 (26 aprile 2021): e0250456. http://dx.doi.org/10.1371/journal.pone.0250456.
Testo completoAbstract (sommario):
In computational biomechanics, two separate types of models have been used predominantly to enhance the understanding of the mechanisms of action of the lumbosacral spine (LSS): Finite element (FE) and musculoskeletal multibody (MB) models. To combine advantages of both models, hybrid FE-MB models are an increasingly used alternative. The aim of this paper is to develop, calibrate, and validate a novel passive hybrid FE-MB open-access simulation model of a ligamentous LSS using ArtiSynth. Based on anatomical data from the Male Visible Human Project, the LSS model is constructed from the L1-S1 rigid vertebrae interconnected with hyperelastic fiber-reinforced FE intervertebral discs, ligaments, and facet joints. A mesh convergence study, sensitivity analyses, and systematic calibration were conducted with the hybrid functional spinal unit (FSU) L4/5. The predicted mechanical responses of the FSU L4/5, the lumbar spine (L1-L5), and the LSS were validated against literature data from in vivo and in vitro measurements and in silico models. Spinal mechanical responses considered when loaded with pure moments and combined loading modes were total and intervertebral range of motions, instantaneous axes and centers of rotation, facet joint contact forces, intradiscal pressures, disc bulges, and stiffnesses. Undesirable correlations with the FE mesh were minimized, the number of crisscrossed collagen fiber rings was reduced to five, and the individual influences of specific anatomical structures were adjusted to in vitro range of motions. Including intervertebral motion couplings for axial rotation and nonlinear stiffening under increasing axial compression, the predicted kinematic and structural mechanics responses were consistent with the comparative data. The results demonstrate that the hybrid simulation model is robust and efficient in reproducing valid mechanical responses to provide a starting point for upcoming optimizations and extensions, such as with active skeletal muscles.
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Lee, Jenchieh, Henryk Flashner e Jill L. McNitt-Gray. "Estimation of Multibody Kinematics Using Position Measurements". Journal of Computational and Nonlinear Dynamics 6, n. 3 (15 dicembre 2010). http://dx.doi.org/10.1115/1.4002507.
Testo completoAbstract (sommario):
A method for the estimation of kinematics of a system of rigid bodies connected by three degrees of freedom rotational joints using position measurements is introduced. In the proposed approach, system kinematics are computed from experimental measurements while preserving important physical and kinematic properties. These properties include system integrity, i.e., preserving interconnections between the bodies, and the entire system dynamic properties, namely, center of mass kinematics and its angular momentum. The computational procedure consists in solving a sequence of optimizations of appropriately formulated objective functions that incorporate the preservation of physical and kinematic properties by employing the penalty function approach. The configuration of the segment kinematics of the system is computed via a quaternion parametrization of orientation that leads to an efficient computation procedure. The sequence of optimization problems is solved using an embedded iteration process. Two studies are presented to demonstrate the performance of the proposed approach: estimations of the kinematics of a simulated three-link model and of an experimentally measured 3D motion of human body during flight phase of a jump. The results of the two studies indicate fast convergence of the algorithm to an optimal solution while accurately satisfying the imposed the constraints.
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Zhakatayev, Altay, Yuriy Rogovchenko e Matthias Pätzold. "Recursive inverse dynamics sensitivity analysis of open-tree-type multibody systems". Nonlinear Dynamics, 13 aprile 2023. http://dx.doi.org/10.1007/s11071-023-08433-7.
Testo completoAbstract (sommario):
AbstractWe present a first-order recursive approach to sensitivity analysis based on the application of the direct differentiation method to the inverse Lagrangian dynamics of rigid multibody systems. Our method is simple and efficient and is characterized by the following features. Firstly, it describes the kinematics of multibody systems using branch connectivity graphs and joint-branch connectivity matrices. For most mechanical systems with an open-tree kinematic structure, this method turns out to be more efficient compared to other kinematic descriptions employing joint or link connectivity graphs. Secondly, a recursive sensitivity analysis is presented for a dynamic system with an open-tree kinematic structure and inverse dynamic equations described in terms of the Lagrangian formalism. Thirdly, known approaches to recursive inverse dynamic and sensitivity analyses are modified to include dynamic systems with external forces and torques acting simultaneously at all joints. Finally, the proposed method for sensitivity analysis is easy to implement and computationally efficient. It can be utilized to evaluate the derivatives of the dynamic equations of multibody systems in gradient-based optimization algorithms. It also allows less experienced users to perform sensitivity analyses using the power of high-level programming languages such as MATLAB. To illustrate the method, simulation results for a human body model are discussed. The shortcomings of the method and possible directions for future work are outlined.
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Puchaud, Pierre, Samuel Hybois, Antoine Lombart, Joseph Bascou, Hélène Pillet, Pascale Fodé e Christophe Sauret. "On the Influence of the Shoulder Kinematic Chain on Joint Kinematics and Musculotendon Lengths During Wheelchair Propulsion Estimated From Multibody Kinematics Optimization". Journal of Biomechanical Engineering 141, n. 10 (15 luglio 2019). http://dx.doi.org/10.1115/1.4043441.
Testo completoAbstract (sommario):
Multibody kinematic optimization is frequently used to assess shoulder kinematics during manual wheelchair (MWC) propulsion, but multiple kinematics chains are available. It is hypothesized that these different kinematic chains affect marker tracking, shoulder kinematics, and resulting musculotendon (MT) lengths. In this study, shoulder kinematics and MT lengths obtained from four shoulder kinematic chains (open-loop thorax-clavicle-scapula-humerus (M1), closed-loop with contact ellipsoid (M2), scapula rhythm from regression equations (M3), and a single ball-and- socket joint between the thorax and the humerus (M4) were compared. Right-side shoulder kinematics from seven subjects were obtained with 34 reflective markers and a scapula locator using an optoelectronic motion capture system while propelling on a MWC simulator. Data were processed based on the four models. The results showed the impact of shoulder kinematic chains on all studied variables. Marker reconstruction errors were found to be similar between M1 and M2 and lower than for M3 and M4. Few degrees-of-freedom (DoF) were noticeably different between M1 and M2, but all shoulder DoFs were significantly affected between M1 and M4. As a consequence of differences in joint kinematics, MT lengths were affected by the kinematic chain definition. The contact ellipsoid (M2) was found as a good trade-off between marker tracking and penetration avoidance of the scapula. The regression-based model (M3) was less efficient due to limited humerus elevation during MWC propulsion, as well as the ball-and-socket model (M4) which appeared not suitable for upper limbs activities, including MWC propulsion.
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Sun, Guangzhen, e Ye Ding. "An Analytical Method For Sensitivity Analysis Of Rigid Multibody System Dynamics Using Projective Geometric Algebra". Journal of Computational and Nonlinear Dynamics, 24 agosto 2023, 1–15. http://dx.doi.org/10.1115/1.4063225.
Testo completoAbstract (sommario):
Abstract The analytical sensitivity analysis, i.e., the analytical first-order partial derivatives of dynamical equations, is one key to improving descent-based optimization methods for motion planning and control of robots. This paper proposes an efficient algorithm that recursively evaluates the analytic gradient of the dynamical equations of a multibody system. The theory of projective geometric algebra (PGA) is used to generate the algorithm. It provides a systemic and geometrically intuitive interpretation for the multibody system dynamics, and the resulting algorithm is highly efficient, with concise formula. The algorithm is first applied to the open-chain system and extended for the cases when kinematic loops are contained. The runtime varying with respect to the degree of freedom (DOF) of the system is analyzed. The results are compared with that obtained from the algorithm based on spatial vector algebra (SVA) using open-source MATLAB codes. A 2-DOF serial robot, a 3-DOF robot with a kinematic loop and the PUMA560 robot are used for the validation of the minimum-effort motion planning, and it is verified that the proposed algorithm improves the efficiency.
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Nasr, Ali, Spencer Ferguson e John McPhee. "Model-Based Design and Optimization of Passive Shoulder Exoskeletons". Journal of Computational and Nonlinear Dynamics 17, n. 5 (14 marzo 2022). http://dx.doi.org/10.1115/1.4053405.
Testo completoAbstract (sommario):
Abstract To physically assist workers in reducing musculoskeletal strain or to develop motor skills for patients with neuromuscular disabilities, recent research has focused on exoskeletons. Designing exoskeletons is challenging due to the complex human geometric structure, the human-exoskeleton wrench interaction, the kinematic constraints, and the selection of power source characteristics. This study concentrates on modeling a 3D multibody upper-limb human-exoskeleton, developing a procedure of analyzing optimal assistive torque profiles, and optimizing the passive mechanism features for desired tasks. The optimization objective is minimizing the human joint torques. Differential-algebraic equations (DAEs) of motion have been generated and solved to simulate the complex closed-loop multibody dynamics. Three different tasks have been considered, which are common in industrial environments: object manipulation, over-head work, and static pointing. The resulting assistive exoskeleton's elevation joint torque profile decreases the specific task's human shoulder torque in computer simulations. The exoskeleton is not versatile or optimal for different dynamic tasks since the passive mechanism produces a specific torque for a given elevation angle. We concluded that designing a fully passive exoskeleton for a wide range of dynamic applications is impossible.