Swaminath Venkateswaran

@article{venkateswaran_2256,

title = {Mapping the Tilt & Torsion angles for a 3-SPS-U parallel mechanism},

author = {Swaminath Venkateswaran and Damien Charles Chablat},

url = {https://www.mdpi.com/2218-6581/12/2/50},

year  = {2023},

date = {2023-03-01},

journal = {Robotics},

volume = {12},

number = {2},

pages = {50},

abstract = {This article presents the analysis of a parallel mechanism of type 3-SPS-U. The usual singularity approach is carried out with respect to the Euler angles of the universal joint. However, this approach is computationally expensive especially when stacked structures are analyzed. Thus, the positioning of the mobile platform for the mechanism is analyzed using the theory of Tilt & Torsion (T&T). The singularity-free workspace and the tilt limits of the mechanism are disclosed through this method. These workspaces can then be mapped to the Euler angles of the universal joint and the relation between the T & T space and the Euler space is demonstrated and validated in this study. Initially, simulations are performed using the results of singularity analysis to have a comparison between the T&T space and the Euler space. Experimental validation is then carried out on the prototype of the mechanism to perform a circular trajectory, in line with the simulations. The outcome of this study will be helpful for the integration of the mechanism for a piping inspection robot and also for the analysis of stacked architectures.},

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tppubtype = {article}

}

@article{venkateswaran_2384,

title = {Stability analysis of tensegrity mechanism coupled with a bio-inspired piping inspection robot},

author = {Swaminath Venkateswaran and Damien Charles Chablat},

url = {https://www.tandfonline.com/doi/abs/10.1080/10255842.2022.2116885},

year  = {2022},

date = {2022-10-01},

journal = {Computer Methods In Biomechanics And Biomedical Engineering},

volume = {25},

number = {1},

pages = {300-302},

abstract = {Piping inspection robots play an essential role for industries as they can reduce the human effort and pose lesser risker to their lives. Generally, the locomotion techniques of these robots can be classified into mechanical and bioinspired. By using slot-follower leg mechanisms, DC-motors and control units, a rigid caterpillar type inspection robot was  designed  and  developed  at  LS2N,  France. This rigid prototype helped in identifying the static forces required to accomplish good contact forces with the pipeline walls. In order to work inside curvatures, a tensegrity mechanism that uses three tension springs and a passive  universal  joint  was  introduced  between  each module of this robot. The optimal parameters of the robot assembly were identified by considering a preloading along the cables, which ensured the stability of the entire robot. However, under static conditions, there exists some forces on the robot,especially on the tensegrity mechanism when one end of the leg mechanisms is clamped with the pipeline walls. These forces are dominant when the orientation of the pipeline is horizontal. The objective of this article is to understand the effect of stiffness of thespring on the static stability of the tensegrity mechanism under the self-weight of the robot assembly.},

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pubstate = {published},

tppubtype = {article}

}

@article{venkateswaran_1788,

title = {An optimal design of a flexible piping inspection robot},

author = {Swaminath Venkateswaran and Damien Charles Chablat and Pol Hamon},

url = {https://asmedigitalcollection.asme.org/mechanismsrobotics/article-abstract/13/3/035002/1096922/An-Optimal-Design-of-a-Flexible-Piping-Inspection},

year  = {2021},

date = {2021-06-01},

journal = {Journal Of Mechanisms And Robotics-Transactions Of The Asme},

volume = {13},

number = {3},

pages = {035002},

abstract = {This study presents an optimization approach for the design of a piping inspection robot. A rigid bio-inspired piping inspection robot that moves like a caterpillar was designed and developed at LS2N, France. By the addition of tensegrity mechanisms between the motor modules, the mobile robot becomes flexible to pass through the bends. However, the existing motor units prove to be oversized for passing through pipe bends at 90 deg. Thus, three cascading optimization problems are presented in this article to determine the sizing of robot assembly that can overcome such pipe bends. The first problem deals with the identification of design parameters of the tensegrity mechanism based on static stability. Followed by that, in the second problem, the optimum design parameters of the robot modules are determined for the robot assembly without the presence of leg mechanisms. The third problem deals with the determination of the size of the leg mechanism for the results of the two previous optimization problems. A digital model of the optimized robot assembly is then realized using cad software.},

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pubstate = {published},

tppubtype = {article}

}

@article{chablat_1789,

title = {Workspace analysis in the design parameter space of a 2-dof spherical parallel mechanism for a prescribed workspace: Application to the otologic surgery},

author = {Damien Charles Chablat and Guillaume Michel and Philippe Bordure and Swaminath Venkateswaran and Ranjhan Jha},

url = {https://www.sciencedirect.com/science/article/pii/S0094114X20304419},

year  = {2021},

date = {2021-03-01},

journal = {Mechanism And Machine Theory},

volume = {157},

number = {3},

pages = {104224},

abstract = {During Otologic surgery, and more broadly during microsurgery, the surgeon encounters several difficulties due to the confined spaces and micro-manipulations. The purpose of the paper is to design a robot with a prescribed regular workspace shape to handle an endoscope to assist the Otologic surgery. A spherical parallel mechanism with two degrees of freedom is analysed in its design parameter space. This mechanism is composed of three legs (2USP-U) to connect the base to a moving platform connected to a double parallelogram to create a remote center of motion (RCM). Its kinematic properties, i.e. the singularity locus and the number of direct kinematic solutions, are investigated. For some design parameters, non-singular assembly modes changing trajectories may exist and have to be investigated inside the prescribed regular workspace shape. Two sets of design parameters are presented with their advantages and disadvantages.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{chablat_1791,

title = {Self-motion conditions for a 3-PPPS parallel robot with delta-shaped base},

author = {Damien Charles Chablat and Erika Ottaviano and Swaminath Venkateswaran},

url = {https://www.sciencedirect.com/science/article/pii/S0094114X18320834},

year  = {2019},

date = {2019-05-01},

journal = {Mechanism And Machine Theory},

volume = {135},

number = {5},

pages = {109-114},

abstract = {This paper presents the self-motion conditions of the 3-PPPS parallel robot with an equilateral mobile platform and an equilateral-shaped base. The study of the direct kinematic model shows that this robot admits self-motion of the Cardanic type as the 3-RPR planar parallel robot where the first revolute joint of each leg is actuated or the PamINSA parallel robot. This property explains why the direct kinematic model admits an infinite number of solutions in the center of the workspace but has never been studied until now. The condition of this singularity is described and the location of the self-motion in the workspace with respect to all the singularities is then presented. The quaternion parameters are used to represent the singularity surfaces and the self-motion conditions in the workspace.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{venkateswaran_1790,

title = {Numerical and Experimental Validation of the Prototype of a Bio-Inspired Piping Inspection Robot},

author = {Swaminath Venkateswaran and Damien Charles Chablat and Frédéric Boyer},

url = {https://www.mdpi.com/2218-6581/8/2/32},

year  = {2019},

date = {2019-04-01},

journal = {Robotics},

volume = {8},

number = {2},

pages = {32},

abstract = {Piping inspection robots are of greater importance for industries such as nuclear, chemical and sewage. Mechanisms having closed loop or tree-like structures can be employed in such pipelines owing to their adaptable structures. A bio-inspired caterpillar type piping inspection robot was developed at Laboratoire des Sciences du Numérique de Nantes (LS2N), France. Using DC motors and leg mechanisms, the robot accomplishes the locomotion of a caterpillar in six-steps. With the help of Coulomb's law of dry friction, a static force model was written and the contact forces between legs of robot and pipeline walls were determined. The actuator forces of the DC motors were then estimated under static phases for horizontal and vertical orientations of the pipeline. Experiments were then conducted on the prototype where the peak results of static force analysis for a given pipe diameter were set as threshold limits to attain static phases inside a test pipeline. The real-time actuator forces were estimated in experiments for similar orientations of the pipeline of static force models and they were found to be higher when compared to the numerical model.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{chablat_1793,

title = {Mechanical Design Optimization of a Piping Inspection Robot},

author = {Damien Charles Chablat and Swaminath Venkateswaran and Frédéric Boyer},

url = {https://www.sciencedirect.com/science/article/pii/S2212827118300799},

year  = {2018},

date = {2018-05-01},

journal = {Procedia CIRP},

volume = {70},

number = {5},

pages = {307-312},

abstract = {The piping inspection for security or sealing checking is an important challenge when the internal diameter of the pipe is small with respect to its length. Some mechanisms using closed loops are able to generate contact forces and deployable structures. By using bio-inspired design, we present a mechanism which is able to move inside pipes by mimicking the motion of a caterpillar. The mechanism is composed of three sections, one for the motion and two with legs that are attached with the inner part of the pipe. A compliant mechanism is proposed to add mobility between the three sections of the robot in order to cross the singularity of the pipe. The results coming from a multi-objective optimization process is used to set the geometric and kinematic parameters of the mechanism taking into account the environmental and design constraints. A mechatronic system is proposed that uses industrial components namely DC motors, ball-screws and servo controllers which can be inserted in the pipe. For horizontal and vertical motions, the contact forces and the motor torques are computed to check the feasibility of the clamping. A prototype made at Laboratoire des Sciences du Numérique de Nantes (LS2N) is used to show the behavior of this concept for slow motions.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}