Mecánica aplicada

312 p.Índice: 1. Sistemas de fuerzas. 2. Centroides. 3. Equilibrio estático. 4. Rozamiento. 5. Cables. 6. Cinemática del sólido rígido. 7. Cinemática del movimiento plano. 8. Propiedades de inercia de sólido. 9. Dinámica del sólido rígido. 10. Dinámica del sólido con eje fijo. 11. Dinámica plana. 12. Propiedades de inercia de área. 13. Esfuerzos internos. 14. Tensiones normales

Design of an active reconfigurable 2R joint

Ponencia presentada en 15th IFToMM World Congress on Mechanism and Machine ScienceThe increasing flexibility requirements in the manufacturing processes has led to the development of novel reconfigurable mechanisms to be implemented in ma-chine heads and tables. This is the case of the reconfigurable parallel manipulators which are also used in a wide variety of applications. These mechanisms include often in their kinematic chains active or reconfigurable joints. In this paper, a 2R active reconfigurable joint is presented. As well as carrying out the kinematic characterization of the joint, a demonstrative prototype has been also built.The authors wish to acknowledge the financial support received from the Spanish Government through the Ministerio de Economía y Competitividad (Project DPI2015-67626-P (MINECO/FEDER, UE)) and the financial support given to the research group through the pro-ject with Ref. IT949-16, given by the Departamento de Educación, Política Lingüística y Cultura of the Regional Government of the Basque Country

Parallel manipulators: practical applications and kinematic design criteria. Towards the modular reconfigurable robots

Post-PrintModern robotic manipulators play an essential role in industry, developing several tasks in an easy way, enhancing the accuracy of the final product and reducing the executing time. Also they can be found in other fields as aerospace industry, several medical applications, gaming industry, and so on. In particular, the parallel manipulators have acquired a great relevance in the last years. Indeed, many research activities and projects deal with the study and develop-ment of this type of robots. Nevertheless, usually, a bilateral communication between industry and research does not exist, even among the different existing research areas. This causes a lack of knowledge regarding works that have been carried out, the ones that are under devel-opment and the possible future investigations. Hence, once a specific field of knowledge has acquired a certain level of maturity, it is convenient to reflect its current state of the art. In this sense, the authors of this paper present a review of the different fields in which parallel ma-nipulators have a significant participation, and also the most active research topics in the anal-ysis and design of these robots. Besides, several contributions of the authors to this field are cited.The authors wish to acknowledge the financial support received from the Spanish Government through the "Ministerio de Economía y Competitividad" (Project DPI2015-67626-P (MINECO/FEDER, UE)), the financial support from the Uni-versity of the Basque Country (UPV/EHU) under the program UFI 11/29 and the support to the research group, through the project with ref. IT949-16, given by the "Departamento de Educación, Política Lingüística y Cultura" of the Regional Government of the Basque Country

Improving Skills in Mechanism and Machine Science Using GIM Software

The field of education has evolved significantly in recent years as it has incorporated new pedagogical methodologies. Many of these methodologies are designed to encourage students’ participation in the learning process. The traditional role of the student as a passive receiver of content is no longer considered valid. Teaching in mechanical engineering is no stranger to these changes either, where new learning activities have been designed to complement theory-heavy lectures. These activities take place in both physical and virtual laboratories. In case of the latter, the use of the GIM software (developed at the Department of Mechanical Engineering of the University of the Basque Country UPV/EHU, Spain) is a promising option. In this paper, features of the GIM that are most frequently used to support and exemplify the theoretical concepts taught in lectures are described using a case study. In addition, GIM is integrated into different learning activities to show its potential as a tool for learning and self-evaluation.This research was funded by Ministerio de Economía y Competitividad, Spanish Government Project, MINECO/FEDER, UE (grant number DPI2015-67626-P), Departamento de Educación, Política Lingüística y Cultura, Regional Government of the Basque Country (grant number IT949-16) and University of the Basque Country UPV/EHU (grant number PIE2012/14)

Translational parallel manipulator with Pa2 kinematic joints

The kinematic pair Pa2 is composed of two interlinked parallelograms. It has two degrees of freedom that generate a translational plane variable with position. It has a structure different from the PaPa pair, which is composed also by two parallelograms but generates a constant translational plane. Currently, the Pa2 pair is used at conceptual level but it is not used in al-most any practical application. There are advantages and drawbacks in using it. The main drawback is the high number of redundant constraints that this pair possesses. However, sub-stituting carefully the revolute joints by spherical joints can eliminate these redundant con-straints. Also, this pair constitutes a more rigid structure that replaces adequately the problem-atic passive prismatic joints. In this paper, will be presented a preliminary study of a translational parallel manipulator (PM) based on the use of the Pa2 pair: the 3-PPa2 that contains redundant constraints in its global structure. To study the potentiality of the PM presented in this paper, the following analyses will be done: position and velocity (direct and inverse kinematics), workspace and singularity analysis. Also the potentiality to be optimised will be studied.This work was supoorted by the Spanish Government through the Ministerio de Economía y Competitividad (Project DPI2015-67626-P (MINECO/FEDER, UE)), the financial support from the University of the Basque Country (UPV/EHU) under the program UFI 11/29 and the support to the research group, through the project with ref. IT949-16, given by the Departamento de Educación, Política Lingüística y Cultura of the Regional Government of the Basque Country

Multioperation capacity of parallel manipulators basing on generic kinematic chain approach

The idea of designing multioperation mechanisms capable of performing different tasks has gained prominence in the last years. These mechanisms, commonly called reconfig- urable mechanisms, have the ability to change their configuration. At present, this type of mechanisms is capturing the attention of design engineers because of their great po- tential in many industrial applications. In this paper, the basis for the development of a methodology intended for the analysis and design of multioperational parallel manipu- lators is presented. First, the structural synthesis of 6 degree-of-freedom (dof) kinematic chains that can form a 6 dof manipulator is established. Next, a general purpose approach for non-redundant parallel manipulators (PM) will be presented. This procedure enables obtaining the Jacobian matrices of any 6 dof or low-mobility PM whose kinematic chains belong to the library of chains derived from the structural synthesis. To demonstrate the versatility of the procedure, it will be applied to three PM: the first one, a 6 dof PM, the second one, a reconfigurable 6 dof PM, and finally, a low-mobility PM.This work was supoorted by the Spanish Government through the Ministerio de Economía y Competitividad (Project DPI2015-67626-P (MINECO/FEDER, UE)), the financial support from the University of the Basque Country (UPV/EHU) un- der the program UFI 11/29 and the support to the research group, through the project with ref. IT949-16 , given by the Departamento de Educación , Política Lingüística y Cultura of the Regional Government of the Basque Country

Dynamics and mechanical vibrations. Complementing the theory with virtual simulation and experimental analysis

Conference paper presented at The second International Symposium on the Education in Mechanism and Machine Science (ISEMMS 2017)The purpose of the present work is to show how the complex theory in subjects related to Mechanism and Machine Theory can be reinforced with some practicals in which the students can perform virtual simulation of the mechanisms under study, and they can even interact with real prototypes to validate by means of experimental analysis the theoretical results. This works deals with Dynamics and Mechanical Vibrations, and presents the capacities of the Dynamics module implemented in GIM software related to the obtaining of free solid diagrams, internal forces maps and diagrams, motion simulation, and so on. In addition to this, interacting with prototypes to carry out experimental measures is also proposed, so that the students can acquire a deeper understanding of some phenomena related to mechanical vibrationsThis work was supported by the Spanish Government through the Ministerio de Economía y Competitividad (Project DPI2015-67626-P (MINECO/FEDER, UE)), the financial support from the University of the Basque Country (UPV/EHU) under the program UFI 11/29 and the support to the research group, through the project with ref. IT949-16, given by the Departamento de Edu-cación, Política Lingüística y Cultura of the Regional Government of the Basque Country

Devices for gait and balance rehabilitation: General classification and a narrative review of end effector-based manipulators

Gait and balance have a direct impact on patients’ independence and quality of life. Due to a higher life expectancy, the number of patients suffering neurological disorders has increased exponentially, with gait and balance impairments being the main side effects. In this context, the use of rehabilitation robotic devices arises as an effective and complementary tool to recover gait and balance functions. Among rehabilitation devices, end effectors present some advantages and have shown encouraging outcomes. The objective of this study is twofold: to propose a general classification of devices for gait and balance rehabilitation and to provide a review of the existing end effectors for such purposes. We classified the devices into five groups: treadmills, exoskeletons, patient-guided systems, perturbation platforms, and end effectors. Overall, 55 end effectors were identified in the literature, of which 16 were commercialized. We found a disproportionate number of end effectors capable of providing both types of rehabilitation (2/55) and those focused on either balance (21/55) or gait (32/55). The analysis of their features from a mechanical standpoint (degrees of freedom, topology, and training mode) allowed us to identify the potential of parallel manipulators as driving mechanisms of end effector devices and to suggest several future research directions.This research received financial support for the project PID2019-105262RB-I00 funded by MCIN/AEI/10.13039/501100011033 and for the project PDC2022-133787-I00 funded by MCIN/AEI/10.13039/501100011033 and by the European Union Next Generation EU/PRTR. This research was also funded by the Basque Government for the project 2018222013 and PhD grant PRE_2023_2_0168