Soft robotic manipulators have been created and investigated for a number of applications due to their advantages over rigid robots. In minimally invasive surgery, for instance, soft robots have successfully demonstrated a number of benefits due to the compliant and flexible nature of the material they are made of. However, these type of robots struggle with performing tasks that require on-demand stiffness i.e. exerting higher forces to the surrounding environment. A number of semi-active and active mechanisms have been investigated to change and control the stiffness of soft robotic manipulators. Embedding these mechanisms in soft manipulators for spacerestricted applications can be challenging though.To better understand the inherent passive stiffness properties of soft manipulators, we propose a screw theory-based stiffness analysis for fluidic-driven continuum soft robotic manipulators. First, we derive the forward kinematics based on a parameterbased piece-wise constant curvature model. It is worth noting, our stiffness analysis can be conducted based on any freespace forward kinematic model. Then our stiffness analysis and mapping methodology is conducted based on screw theory. Initial results of our approach demonstrate the feasibility comparing computational and experimental data.
Recently, industrial robots are being more and more widely used in a variety of machining applications, such as drilling, milling and grinding because of their flexibility in performing tasks in a relatively small space, and furthermore, at a lower cost. In many cases, the wrench capability of industrial robots is lower than the required, causing in some tasks the saturation of the actuators. The possibility of using two or more robots to perform a given task increases the wrench capability, allowing us to work out in applications which are impossible to solve using only one manipulator. A Cooperative Robotic System (CRS) increases the flexibility in the performance of tasks allowing a more homogeneous distribution of the forces generated during the interaction between the end-effector and the environment. In some cases, the CRS can be composed by robots with different capabilities, and a strategy for wrench distribution must be used. Recent works presented the force capability analysis using a scaling factor method for single serial robots. This paper proposes the use of this scaling factor method in CRS, seeking to obtain a balance of forces between the robots. The proposed method is discussed and graphical results are presented.
RESUMOA Engenharia de Tecidos pode ser definida como um conjunto de competências pela união das Engenharias, Biologia e Medicina, cujo principal objetivo é o desenvolvimento de novos materiais com o intuito de substituir ou restaurar órgãos já lesionados. Um dos grandes desafios na regeneração de defeitos ósseos localizados em regiões sob carga é o desenvolvimento de scaffolds, a elaboração da arquitetura, associando o tamanho de poros com a geometria ideal para fornecer uma resistência à compressão comparável ao osso cortical (100-150 MPa). O objetivo deste trabalho é desenvolver geometrias para os scaffolds, com aplicações em regeneração óssea, afim de comparar a resistência à compressão entre os modelos e o comportamento morfológico resultante da manufatura aditiva. Para isso, como metodologia do trabalho, utilizando bases científicas, definiu-se parâmetros para o desenvolvimento de scaffolds, utilizou-se ácido poliláctico (PLA) como biomaterial manufaturado através do processo Fused Deposition Modeling (FDM) de manufatura aditiva, desenvolveu-se três modelos de geometrias para a realização dos ensaios de compressão e análise morfológica utilizando-se a tecnologia de Microscopia Eletrônica por Varredura (MEV). O modelo de geometria Squarebar, dentre os três modelos analisados, apresentou melhores resultados, permitiu que o scaffold suporte uma resistência à compressão de 20,19 MPa, tendo os poros com tamanho de aproximadamente 870 μm de altura e 700 μm de largura. De modo geral, pode-se afirmar que a utilização de scaffolds de PLA para a aplicação na região de ossos esponjosos tornam-se adequados com o objetivo de regeneração celular e óssea.
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