In this paper a 2-DOF parallel mechanism used for orientation is presented. This mechanism could be applied for orientation of the TV satellite antennas, sun trackers etc. Based on the kinematic scheme of the mechanis...
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ISBN:
(纸本)9789048196883
In this paper a 2-DOF parallel mechanism used for orientation is presented. This mechanism could be applied for orientation of the TV satellite antennas, sun trackers etc. Based on the kinematic scheme of the mechanism, the algorithms for the kinematic models are solved, the workspace and singularities are described and analyzed. An optimal design of the mechanism is performed. Finally, the design of the mechanism is also described.
This paper focuses on the study of static and dynamic stiffness (normal modes and natural frequencies) by a method which enables to evaluate the vibration behaviour of low mobility parallel manipulators, i.e., less th...
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ISBN:
(纸本)9789048196883
This paper focuses on the study of static and dynamic stiffness (normal modes and natural frequencies) by a method which enables to evaluate the vibration behaviour of low mobility parallel manipulators, i.e., less than 6 degrees-of-freedom. The purpose of this study is to improve the structural behaviour of this type of manipulators under the effect of static and dynamic external loads. As a starting point, we use a previously developed methodology for static rigidity obtaining for the aforementioned manipulators characteristics, using as case study DAEDALUS I parallel robot. The method is applied to a simplified model to analyze the evolution of the static stiffness, the frequencies and normal modes in the whole workspace. The method involves the use of one analytical model, other numerical, based on finite elements and a comparison with an experimental campaign on a prototype. From this study, the results of the natural frequencies trends of the manipulator are represented in tridimensional maps.
The paper presents an analytical and computer-aided procedure for the prediction of the dynamic transmission error of helical gear pairs by using variable mesh stiffness. An improved model of the mesh stiffness is dev...
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ISBN:
(纸本)9789048196883
The paper presents an analytical and computer-aided procedure for the prediction of the dynamic transmission error of helical gear pairs by using variable mesh stiffness. An improved model of the mesh stiffness is developed by including specific meshing characteristics of helical gear pairs. The effects of addendum modification coefficients and face-width of gear pairs on the time varying mesh stiffness are investigated. A comparative study has been performed to analyze the effect of the total contact ratio and its components on the dynamic transmission error of helical gear pairs.
Considering the latest results in robotic assisted surgery it is obvious that robots became useful tools in minimally invasive surgery (MIS), providing benefits such as reduction in hand tremor, the possibility of rea...
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ISBN:
(纸本)9789048196883
Considering the latest results in robotic assisted surgery it is obvious that robots became useful tools in minimally invasive surgery (MIS), providing benefits such as reduction in hand tremor, the possibility of reaching positions and places that could prove difficulty in reaching using classical instruments, navigation and workspace scaling. In this paper the inverse dynamic model for a parallel robot conceived for MIS using virtual work principle is presented. The results of the analytic dynamic model have been validated by means of a Multi-Body simulation.
The paper presents a calculation method of the forces and the moments that operate in the rotation and translation couplings from the serial industrial robots structure. Through using some methods and calculation prog...
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ISBN:
(纸本)9789048196883
The paper presents a calculation method of the forces and the moments that operate in the rotation and translation couplings from the serial industrial robots structure. Through using some methods and calculation programs, the forces and moments, used for dimensioning the mechanisms and driving motors from couplings, can be accurately determined. The theoretical relations and the calculations programs also take into consideration the friction forces acting in couplings and the working cyclogram.
science and engineering teaching are a challenge in the modern world, and in particular in Romania. We present the steps we have taken in the last decade and in particular in the last five years, to improve mechanisms...
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ISBN:
(纸本)9789048196883
science and engineering teaching are a challenge in the modern world, and in particular in Romania. We present the steps we have taken in the last decade and in particular in the last five years, to improve mechanisms teaching. We have gradually passed in this process from classical to hands-on-experiments and to research-oriented activities, in order to provide the proper background for each student to find personal motivation and to develop both as a specialist and as a more fulfilled person. Several student projects we have coordinated are pointed out, and our vision on a modern school of engineering is compared to and confirmed by some of the realities of the American academic system.
In order to improve the absolute positioning abilities of the 3-PRR planar parallel robot MICABO(es), its kinematic model is adapted to take the predictable motion of flexure hinges into consideration. This is accompl...
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ISBN:
(纸本)9789048196883
In order to improve the absolute positioning abilities of the 3-PRR planar parallel robot MICABO(es), its kinematic model is adapted to take the predictable motion of flexure hinges into consideration. This is accomplished by replacing the idealized rotations within the kinematic model with a complexer rotational model. A set of kinematic equations is derived for the robot which is solved using an iterative method. A method for calibrating these equations is then explained and a simulation is used to show its success implementation.
The dynamic modeling and simulation of spatial multibody systems with lubricated spherical joints is the main purpose of the present work. When the spherical clearance joint is modeled as dry contact;i.e., when there ...
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ISBN:
(纸本)9789048196883
The dynamic modeling and simulation of spatial multibody systems with lubricated spherical joints is the main purpose of the present work. When the spherical clearance joint is modeled as dry contact;i.e., when there is no lubricant between the mechanical elements which constitute the joint, a body-to-body (typically metal-to-metal) occurs. The joint reaction forces in this case are evaluated through a Hertzian-based contact law. The presence of a fluid lubricant avoids the direct metal-to-metal contact. In this situation, the squeeze film action, due to the relative approaching motion between the mechanical joint elements, is considered utilizing the lubrication theory associated with the spherical bearings. In both cases, the intra-joint reaction forces are evaluated as functions of the geometrical, kinematical and physical characteristics of the spherical joint. These forces are then incorporated into a standard formulation of the system's governing equations of motion as generalized external forces. A spatial four bar mechanism that includes a spherical clearance joint is considered here as example.
In the paper the first developed voice-controlled parallel robot PARAMIS (PARAllel robot for Minimally Invasive Surgery) in Romania, used for laparoscope. camera positioning in the minimally invasive surgery, is prese...
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ISBN:
(纸本)9789048196883
In the paper the first developed voice-controlled parallel robot PARAMIS (PARAllel robot for Minimally Invasive Surgery) in Romania, used for laparoscope. camera positioning in the minimally invasive surgery, is presented. The development of the structure focused on the achievement of a simple, lightweight, cheap solution, able to work alone or as part of a multi arm robotic system. The adopted solution for the voice commands interface is presented. Some experimental results are illustrated pointing out the behavior of the robot in a surgical procedure.
This paper deals with the optimal dimensional design of Delta robot. The aim is to obtain a manipulator with maximum dexterity and minimum projected area of the occupied volume on the base plane. Two different optimiz...
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ISBN:
(纸本)9789048196883
This paper deals with the optimal dimensional design of Delta robot. The aim is to obtain a manipulator with maximum dexterity and minimum projected area of the occupied volume on the base plane. Two different optimization strategies, which cope with assembly difficulties, have been applied to solve this problem. Comparing optimized Delta robot with and without area reduction, results show an important reduction of area maintaining an acceptable dexterity.
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