1,720,997 research outputs found
Design and implementation of an ERLS-based 3-D dynamic formulation for flexible-link robots
No full textModeling and dynamic analysis of robots with flexible-links are still an open field of research. Indeed, to design and control effective light robot manipulators and high-performance flexible mechanisms for efficient manufacturing systems, an accurate dynamic model representing the system behavior is necessary. In this work, a novel method for dynamic modeling of 3-D robots with large displacements and small elastic deformations is developed by means of an Equivalent Rigid Link System (ERLS) approach. Thanks to this, the kinematic equations of the Equivalent Rigid Link System and the compatibility equations of the displacements at the joints are always decoupled. After the theoretical development, the kinematic and dynamic models have been implemented ona MatlabTM software simulator and validated
A method for modeling three-dimensional flexible mechanisms based on an equivalent rigid-link system
No full textAccurate modeling of flexible mechanisms is an open research topic, and different models have been presented since the 1970s. In this work, a novel approach for modeling of three-dimensional flexible mechanisms is presented, based on an equivalent rigid-link system, with respect to which elastic deformations are defined and computed. Concepts of three-dimensional kinematics are used in order to define an effective relationship between the rigid body and the elastic motion. The model is based on a compact kinematic formulation and, for a specific mechanism, there is no need for customizing the formulation. By using the principle of virtual work, a coupled dynamic formulation is found. A crucial advantage of this method is that it is not necessary to explicitly formulate the compatibility equations expressing the link connections, since they are included in the matrices of the system dynamics. The model was applied to a specific three-dimensional flexible mechanism. The results, compared with the Adams-FlexTM software, show a good agreement, thus proving the effectiveness of the methodology
DFORCE: Delayed FOrce ReferenCE control for master–slave robotic systems
No full textThe acceptance of master–slave robotic teleoperated applications in the medical field is related not only
to the accuracy and precision of the robotic systems but also to the haptic features. Indeed, the capability
to render a good haptic feeling, hence the sensation to drive the real surgical tool, is necessary for reaching
an effective interaction between surgeon and robotic system.
In this paper an innovative controller for master–slave haptic systems for neurosurgery has been developed
by getting inspiration from force reflecting controllers and non-time based control schemes. This
new DFORCE (Delayed FOrce ReferenCE) controller is founded on the basic idea to control the position
of the device through a system that can generate forces on the master side only when the surgeon is
grasping the haptic handle. Thus, when the surgeon is not grasping the haptic handle and external forces
are present, the system remains stable.
The haptic sensation, the stability and the readiness of the system have been studied and a tuning procedure
proposed. Moreover, simulated and experimental tests on a test-bed master system and a haptic
master–slave interface for neurosurgical operations have been carried out in order to demonstrate the
effectiveness of the controller
A new kinematic performance index for surgical robots design
No full textIn the last years a large number of new surgical devices has been developed so to improve the operation outcomes and reduce the patient's trauma. Nevertheless the dexterity and accuracy required in positioning the surgical devices are often unreachable if the surgeons are not assisted by a suitable system. Since a medical robot works in an operating room, close to the patient and the medical staff, it has to satisfy much stricter requirements with respect to an industrial one. From a kinematic point of view, the robot must reach any target position in the patient's body being less invasive as possible for the surgeon's workspace. In order to meet such requirements a suitable performance index to optimal kinematic design is needed. This paper proposes an optimal index which maximizes the robot workspace and minimizes the invasiveness with respect to the surgeon's workspace. The index is used to evaluate the performances of a commercial medical robot and will be very useful in the future design of a new special robot for neurosurgery
An intelligent framework to manage robotic autonomous agents
No full textIn this paper a joint application of Artificial Intelligence (AI), robotics and Web services is described. The aim of the work presented here was to create a new integrated framework that keeps advantage on one side of the sensing and exploring capabilities of the robotic systems that work in the real world and, on the other side, of the information available via Web. Robots are conceived like (semi-)autonomous systems able to explore and manipulate a portion of their environment in order to find and collect information and data. On the other hand, theWeb, that in a robotic domain is usually considered like a channel of communication (e.g. tele-operation, tele-manipulation), here is conceived also like a source of knowledge. This allows to define a new framework able to manage robotic agents in order to get precise, real-time information from the real world. Besides, software agents may search for and get additional information from the Web logical world. The intelligent administration of these services can be applied in different environments and leads to optimize procedures and solve practical problems. To this end a traffic control application has been defined and a simplified test-case implemented
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