1,721,127 research outputs found
Two Different Numerical Approaches for Supporting Vibration-Based Structural Health Monitoring of Gear Train Systems
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On the improvement of the combination of Power and Force Limiting and Speed and Separation Monitoring for an effective Human Robot Collaboration
Full text linkIn industrial human-robot collaborative tasks it is of paramount importance to guarantee safety, productivity and fluency. To this scope, beyond the two collaborative modalities introduced by the ISO/TS 15066 (Speed and Separation Monitoring - SSM and Power and Force Limiting - PFL), a modality that combines SSM and PFL to further enhance productivity of a collaborative task has been proposed in literature. However, such method, while guaranteeing an improvement with respect to the two modalities foreseen by the ISO/TS 15066, relies on some conservative assumptions that limit its potentialities. In this work, a method to overcome these limitations is presented and its effectiveness is validated through numerical simulations. Results show that the novelty introduced in this paper leads to an improvement in terms of productivity, fluency of the operation and in usage of the robot, without affecting the safety of the collaborative tasks
Safe and Fluent Industrial Human Robot Collaboration Via Combination of PFL, SSM and Escape Trajectories
No full textOn the Methodologies to Compute Minimum Jerk Trajectories and Their Application in Collaborative Robotics
No full textEnergy-saving optimization method for point-to-point trajectories planned via standard primitives in 1-DoF mechatronic systems
Full text linkIn this work, an analytical methodology to minimize the energy expenditure of mechatronic systems performing point-to-point (PTP) trajectories based on well-known motion primitives is developed and validated. Both PTP trajectory profiles commonly used in industrial motor drives and more complex ones are investigated. Focusing on generic 1-DoF mechatronic systems moving a constant inertia load (e.g., elevators, cranes, CNC machines, Cartesian axis) and possibly equipped or retrofitted with regenerative devices, the consumed energy formulation is firstly derived. Then, the analytical optimization considering all the selected PTP trajectory profiles is computed and a generic closed-form solution is determined. Finally, numerical and experimental evaluations are done showing the effectiveness of the theoretical results and proposed methodology. In addition, all the different trajectories are compared with respect to energy consumption
Flexible-link multibody system eigenvalue analysis parameterized with respect to rigid-body motion
Full text linkThe dynamics of flexible multibody systems (FMBSs) is governed by ordinary differential equations or differential-algebraic equations, depending on the modeling approach chosen. In both the cases, the resulting models are highly nonlinear. Thus, they are not directly suitable for the application of the modal analysis and the development of modal models, which are very useful for several advanced engineering techniques (e.g., motion planning, control, and stability analysis of flexible multibody systems). To define and solve an eigenvalue problem for FMBSs, the system dynamics has to be linearized about a selected configuration. However, as modal parameters vary nonlinearly with the system configuration, they should be recomputed for each change of the operating point. This procedure is computationally demanding. Additionally, it does not provide any numerical or analytical correlation between the eigenpairs computed in the different operating points. This paper discusses a parametric modal analysis approach for FMBSs, which allows to derive an analytical polynomial expression for the eigenpairs as function of the system configuration, by solving a single eigenvalue problem and using only matrix operations. The availability of a similar modal model, which explicitly depends on the system configuration, can be very helpful for, e.g., model-based motion planning and control strategies towards to zero residual vibration employing the system modal characteristics. Moreover, it allows for an easy sensitivity analysis of modal characteristics to parameter uncertainties. After the theoretical development, the method is applied and validated on a flexible multibody system, specifically using the Equivalent Rigid Link System dynamic formulation. Finally, numerical results are presented and discussed
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