Mihir Kumar Sutar

A geometric approach for inverse kinematics of a 4-link redundant In-Vivo robot for biopsy

The presence of a large number of degrees of freedom enables redundant manipulators to have some desirable features like reaching difficult areas and avoiding obstacles. These manipulators in the form of In-Vivo robots will enhance the dexterity and capacity of a surgeon to explore the internal cavity when inserted in the existing tool channel of the endoscope to take a biopsy from the stomach. This paper presents a simple geometric approach, to solve the problem of multiple inverse kinematic solutions of redundant manipulators, to find a single optimum solution and to easily switch from one solution to another depending upon the path and the environment. A simulation model of this approach has been developed and experiments have been conducted on the In-Vivo robot to judge its effectiveness.

Design and Development of In Vivo Robot for Biopsy

In vivo robot is an emerging medical technology that could greatly help biopsy and surgery. This paper proposes to design and develop a miniature in vivo robot for biopsy as an add-on to the current endoscope. To allow more dexterity and flexibility, a four degree of freedom (DOF) robot manipulator is proposed. Accordingly, a wire actuated robot with articulated links like in a snake robot has been conceptualized. The robot was mathematically modeled and designed. To test the design, a 4-scaled aluminum model was manufactured. The kinematics of the model is verified experimentally. The four degree of freedom of the miniature robot are: a linear motion of the flexible shaft (first DOF); an axial rotation of the flexible shaft (second DOF); planar through differential wire movement (third DOF); and a combined wire motion for clipper action to take biopsy (fourth DOF). The proposed robot manipulator was modeled in SolidWorks and the kinematic and dynamic analysis was performed using the Robotics Toolbox in MATLAB.

Forward kinematic analysis of in-vivo robot for stomach biopsy

The introduction of robotic medical assistance in biopsy and stomach cavity exploration is one of the most important milestones in the field of medical science. The research is still in its infancy and many issues like limitations in dexterity, control, and abdominal cavity vision are the main concerns of many researchers around the globe. This paper presents the design aspects and the kinematic analysis of a 4 degrees of freedom (DOF) hyper-redundant in-vivo robot for stomach biopsy. The proposed robot will be inserted through the tool channel of a conventional 4-DOF endoscope and this will increase the dexterity and ease in reaching the furthest parts of the stomach beyond the duodenum. Unlike the traditional biopsy tool, the present design will enhance dexterity due to its 4 DOF in addition to the endoscope’s DOF. The endoscope will be positioned at the entrance to the stomach in the esophagus and the robot will move to the desired position inside the stomach for biopsy and exploration. The current robot is wire-actuated and possesses better maneuverability. The forward kinematic analysis of the proposed robot is presented in this paper.

Vibration Characteristics of a Cracked Cantilever Beam under Free Vibration

The objective of this paper is to perform free vibration analysis of a cracked cantilever and to analyze the relation between the modal natural frequency with crack depth, modal natural frequency with crack location. Also the relation among the crack depth, crack location and natural frequency has been analyzed. Only single cracks at different depths and at different locations are evaluated. And the analysis reveals a relationship between crack depth and modal natural frequency. As we know when a structure suffers from damage its dynamic property can change and it was observed that cracks caused a stiffness reduction with an inherent reduction in modal natural frequencies. Consequently it leads to the change in the dynamic response of the beam. The analysis was performed using ALGOR software. Modal natural frequency was found to be decreasing with increases in crack depth. And the same was found to be increasing with increases in crack location from the fixed end.

Inverse kinematics and control of 4-degree-of-freedom wire-actuated in vivo robot

Endoscopes have been in use for many clinical procedures including biopsy and limited surgery. A biopsy is one of its most common applications. For more than a decade, research is in continuation on various limitations encountered by surgeons in this area like dexterity, manoeuverability and controlling of the scope tip to bring it to an exact point of interest. Existing endoscopes have limitations in number of degrees of freedom. To counter this problem, a 4-degree-of-freedom in vivo robot has been proposed by the authors earlier. This article presents an inverse kinematic solution of the wire-actuated in vivo robot for trajectory control. For this, a kinematic analysis has been performed and the tip positions were obtained analytically. For a known tip position, the length of the wire to be wrapped and un-wrapped is decided from the relational approach and accordingly the desired pulley rotation is performed using the proportional–derivative controller. Simulations have been carried out for three different cases and satisfying results were obtained.

Kinematic Analysis of In-Vivo Robot for Stomach Biopsy

Biopsy and abdominal cavity exploration are performed by endoscopes. Traditional endoscopes are having 4 degrees of freedom (DOF) which creates a deficiency in viewing during the cavity exploration. In order to tackle this deficiency a 4 DOF hyper redudant In-Vivo robot has been designed. The robot can be inserted to one of the existing tool channel of the endoscope and can play a vital role for abdominal cavity exploartion and for taking biopsy. Unlike the traditional biopsy tool the present design will enhance the dexeterity due to its 4 DOFs in addition to the enodoscope’s degrees of freedom. The design minimizes the constraining effects of the trocar due to the insertion through esophagus. Main body of the robot arm consists of three links attached with the coupler at the end and then to the flexible shaft. The endoscope tube will be stationed at the entry to the stomach in the esophagus and the robotic arm will be moved to the desired position in stomach for biopsy and exploration. The current robotic arm posses better maneuverability. The kinematic analysis of the proposed robotic arm is being presented in this paper.

Bond Graph Modelling and Control of Hyper-Redundant Miniature Robot for In-Vivo Biopsy

The introduction of robot-assisted minimally invasive techniques to general surgery for performing biopsy and abdominal cavity exploration is a significant development in medical science. The inclusion of in-vivo robot for abdominal biopsy is an achievement in this area and required a constant persuasion for the improvisation of the design and various controlling aspects in it as there is a need of a miniature in-vivo robot as an exploration tool which can be easily controlled, and has high mobility. Development of such devices needs careful modelling and simulation before manufacturing the product for better results. This chapter describes the modelling and control aspects of the miniature hyper-redundant robot for stomach biopsy.

Bond graph modelling of in vivo robot for biopsy

Abstract Endoscopes have been in use for many procedures including limited surgery. And biopsy is one of its very common applications. Existing endoscopes have limitations in number of degrees of freedom. This paper presents a new design of In- Vivo robot. The work presents bond graph model of a robot for taking a biopsy sample inside the stomach. To develop the bond graph model a kinematic analysis is carried out and various transformer modulli required for drawing of bond graph model are evaluated. The developed bond graph model can be used for trajectory or force control of in vivo robots.

Smart detection of damage in a cracked cantilever beam using artificial intelligence

Increasing attention is being given to the detection of damage in structures. For this purpose different newer techniques are being used. In this paper a defect in a cantilever beam in the form of a transverse crack, is investigated using smart techniques such as Fuzzy Logic Controller. The input parameters to the fuzzy controller are relative divergence of first three natural frequencies, and the output parameters of the fuzzy controller are relative crack depth and relative crack location in dimensionless forms. For deriving the fuzzy rules for the controller, theoretical expressions have been developed considering three parameters such as; natural frequencies, crack depths and crack locations. Strain energy release rate has been used for calculating the local stiffnesses of the beam. The local stiffnesses of the beam are dependent on the crack depth. Different boundary conditions are outlined which take into account the crack location. Several fuzzy rules are derived and the Fuzzy controller has been designed accordingly. The experimental setup has been developed for verifying the robustness of the developed fuzzy controller. The developed fuzzy controller can predict the location and depth of the crack in close proximity to actual results.