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A novel method in measuring the stiffness of sensed objects with applications for biomedical robotic systems
Author(s) -
Najarian Siamak,
Dargahi Javad,
Zheng Xiang Zhi
Publication year - 2006
Publication title -
the international journal of medical robotics and computer assisted surgery
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 53
eISSN - 1478-596X
pISSN - 1478-5951
DOI - 10.1002/rcs.75
Subject(s) - stiffness , computer science , measure (data warehouse) , finite element method , computer vision , acoustics , artificial intelligence , simulation , structural engineering , engineering , physics , data mining
Background In this research paper, a new method for determining the compliance of various objects with different mechanical properties is presented. The structure of the proposed tactile sensor assembly is discussed in detail and the performance of the sensor tested experimentally. Methods In order to measure the stiffness of various sensed objects, the sensor consists of two separate parts. The first part is a rigid cylindrical section while the other part is a deformable foam‐like section. As a practical application, the designed sensor is integrated with a typical endoscopic grasper used in minimally invasive surgeries. Two theoretical approaches are employed in our analysis. In the first approach, which is limited to flat surface objects, the stiffness of the object is obtained using a closed‐form formula. In the second approach, which can be applied to objects with complex irregular shapes, the same parameter is computed using finite element analysis. To evaluate the performance of the designed grasper tool, eight sensors were placed on top and bottom jaws of the tool and objects with known modulus of elasticity were placed between the jaws. Results Keeping the magnitude of the applied forces in the range of 0.1–1 N, we managed to measure the stiffness of the sensed objects with reasonable accuracy (an error of about 20%). Comparing the experimental data with the analytical and the numerical approaches proves that there is a good correspondence between the two methods. Conclusions The designed prototype can be used in various biomedical robotic procedures when performing minimally invasive surgeries. For the first time, we managed to make an endoscopic prototype suitable for measuring stiffness. Copyright © 2006 John Wiley & Sons, Ltd.