• SUMMARY

    Hi, my name is Ranjan Jha and I specialize in Robotics. Now I work as a scientist at CSIR- Central Scientific Instruments Organisation in the BioMedical Application division. I love working with passionate people and sharing what I've learned with them. This website is my window to the world where you can find more about me and then get in touch for a chat about potential projects.

     

    I was a postdoctoral fellow at Polytechnique Montreal, Canada in the Department of Mechanical engineering. I received my Ph.D. in robotics (as Erasmus Mundus fellow) at IRCCyN, Ecole Centrale de Nantes, France. My thesis focuses on the different aspects which are associated with the planning of a task for the parallel manipulators. Presently I am working to develop the different indigenous medical devices. My research involves Biomedical Instrumentation, mechanism design, Gröbner based computations and Cylindrical Algebraic Decomposition algorithm to compute and study the workspace, singularities, and joint space of the parallel robots, which further extended to check the feasibility of any given trajectories in the workspace.


    In the past, I worked as Research Scholar at Institut de Recherche en Communications et Cybernétique de Nantes (IRCCyN), UMR CNRS 6597, France. Also, I worked as a quick hire scientist with CSIRCentral Scientific Instruments Organisation. There I was working on the implementation of motion transfer and haptics for the surgical robots. I received my master’s degree in Advanced instrumentation Engineering from the Academy of Scientific and Innovative Research.

  • mantra

    Don’t count the days, make the days count.

  • CURRENT POSITION

    CSIR- Central Scientific Instruments Organisation

    Scientist March 2018 – Present

    Bio-Medical Instrumentation, Robotics, Mathematical modeling, Workspace, Jointspace and Singularity analysis of parallel manipulators, Trajectory Planning.

  • PROFESSIONAL QUALIFICATIONS

    Polytechnique Montreal

    Postdoctoral Fellow

    Department of Mechanical Engineering, Jan 2017 - Dec 2017

    •  CAE R.-Fraser Elliott Modelling and Simulation Laboratory.
    • École Polytechnique de Montréal, Canada.
    IRCCyN  Ecole Centrale de Nantes

    Doctor of Philosophy, Ph.D.

    Robotics, Sep 2013 - Sep 2016

    • Institut de Recherche en Communications et Cybernétique de Nantes (IRCCyN), UMR CNRS 6597.
    • Erasmus Mundus Fellow [2013-2016].
    • Ecole Centrale de Nantes, France.
    AcSIR

    Master of Technology, M.Tech

    Advanced Instrumentation Engineering, Aug 2011 – Aug 2013

    • Academy of Scientific and Innovative Research (AcSIR – CSIO), Chandigarh, India. 
    drmgr

    Bachelor of Technology, B.Tech

    Instrumentation & Control Engineering, 2007- 2011

    • Dr. MGR Educational and Research Institute,    Chennai, India.             
    Technocrat Automation

    Advance Training In Industrial Automation

    ATIA Diploma

    • Programmable Logic Controller PLC'S (AB, ABB, Siemens, GE-Fanuc, Omron)
    • Supervisory Control and Data Acquisition SCADA (Wonderware Intouch & Intellution Fix)
    • Variable-frequency drive VFD & Field Instruments
  • TECHNICAL  SKILLS

    Electronic Designing

    OrCAD, Keil uvision4, Rapid PCB Prototyping (PotoMat S62)

       

     

    Mechanical Designing

    AutoCAD, CATIA, DELMIA, 3-D Printing(FORTUS.2250mc)

    Optical Designing

    Optics Software for Layout and Optimization, OSLO

    Material Designing & Simulation

    Material Studio 5.0, Characterization of nanoparticles

    Mathematical Modelling & Simulation

    Maple, Matlab

  • Research projects

    Accuracy Analysis of Parallel Robots

    <Read More>

    This contribution dealt with the error modeling of the Orthoglide 5-axis thanks to experimental data associated with the trajectory planning parameters. This work reports the influence of static and dynamic parameters on the computation of the error in the pose associated with the trajectory planning made and analyzed with the Orthoglide 5-axis. The accuracy of the path in the Cartesian workspace was studied for five circular trajectories with the same velocity and acceleration profiles. The proposed joint error model which is based on the dynamic properties i.e joint velocities and acceleration of the Orthoglide helps in estimating the error in the Cartesian workspace. We have found out that the trajectory closer to the singularity surface admitted the maximum error and is approximately twice than the trajectory closest to the isotropic posture. Further, from the experimental results it is observed that there is a significant change in the accuracy by changing the starting position of the manipulator. Finally, from the analysis, it can be concluded that by selecting the appropriate location and starting point, the accuracy of the manipulator can be enhanced significantly. For a given trajectory, we can search the optimal starting point and location for the trajectory so that error in the pose of end effector can be minimized.

    Singularity Free Trajectory Planning

    <Read More>

    This work reports the use of algebraic methods to check the feasibility of given trajectories in the workspace. The general method uses the projection of the solutions of the polynomial equations associated with the trajectories in the joint space using a Gröbner based elimination strategy. There is a significant change in the shape of workspace and in the singularity surfaces due to the joint constraints. The proposed method enables us to project the joint constraints in the workspace of the manipulator, which further helps to analyse the projection of the singularities in the workspace with the joint constraints. Such computations ensure the existence of a singular configuration between two poses of the end-effector unlike other numerical or discretization methods. This work highlights that the singularity analysis should be done in the cross product of the workspace and joint space for parallel robots with several assembly and working modes. The single analysis of the singularities in a projection space can introduce spurious singularities. In fact, the algebraic tools does not allow to distinguish the parallel singularities according to the working mode.

    Workspace, Joint Space and Singularities

    <Read More>

    The accurate calculation of the workspace and joint space for the parallel manipulators is a highly addressed research work across the world. One of the crucial steps in the trajectory planning is to check the singularity-free paths in the workspace, which requires the prior knowledge of the workspace for the parallel manipulators. The cylindrical algebraic decomposition method and Gröbner based computations are used to model the workspace in 3T & 2R1T projection spaces, where the orientation of the mobile platform is represented using quaternions. A certified three dimensional plotting is proposed to study the shape of the workspace for different parallel manipulators. The Gröbner based elimination method is used to compute the projection of the singularities in the Cartesian space and the joint space. The generalized notions of the uniqueness domains is also defined for the parallel robot with several operation modes.

    Motion Transfer and Haptics for Robotic Surgery

    <Read More>

    The work discuss about the techniques of motion transfer from master to slave and to implement force feedback from slave to master. Motion is transferred from master surgeon handle to the robotic arm depending on the encoder pulses from master configuration. The pulses from the encoder are processed and fed to the slave, which mimics the hand motion of master configuration. A two channel encoder with dc motor is used in master slave configuration. There is an efficient transfer of hand motion (master) to the end tool (slave) in 2-DoF, 3-DoF and 5-DoF. The scaling (up and down) feature has been implemented algorithmically. The analysis of the tremor data has been done using MATLAB to study the behavior so as to filter it out from the system. The scaling of the tools helps to filter the physiologic tremor that may arise because of the shake in the surgeon’s hand.

    Electrical and Optical Properties of Ferromagnetic Semiconductor- Co Doped TiO2 Nano particles

    <Read More>

    The ability to control spin states of highly mobile electrons at different locations in a semiconductor, and the ability to turn this collective state on and off at will, could lead to much more efficient spin transistors and other devices. In this work, the properties of cobalt (transition metal) doped with titanium dioxide semiconductor material is investigated. The addition of impurity atoms into semiconducting materials is the primary method for controlling the properties of the semiconductor, such as band gap, electrical conductivity & magnetic property. This is routinely performed with bulk semiconductors and, more recently, has been extended to nanoscale semiconductor particular, II-VI and III-V semiconductors. The properties like particle size, electrical conductivity & band gap has been explored with the help of XRD, SEM & UV. VSM is used to characterize the magnetic properties of transition metal doped material. The report from the UV shows a low band gap which appears to be a promising property for using the material in solar cell applications. The paramagnetic nature is observed from VSM, which is useful in low magnetic field application in agriculture.

  • PARALLEL MANIPULATORS

    Analysis of Different Parallel Manipulators using Algebraic Tools [SIROPA]

    3RPS Parallel Manipulator

    3RPS PM

    Manipulator Creation and Analysis

    The robot is the 3-RPS parallel robot with three degrees of freedom. It is the assembly of two equilateral triangles (the base, moving platform) by three identical RPS legs where R is a revolute passive joint, P an actuated prismatic joint and S a passive spherical joint. The revolute joint is connected to the fixed base and the spherical joint to the mobile platform.

    Orthoglide

    OrthoGlide

    Manipulator Creation and Analysis

    The Orthoglide mechanism is driven by three actuated orthogonal prismatic joints. A simpler virtual model can be defined for the Orthoglide, which consists of three bar links connected by the revolute joints to the tool center point on one side and to the corresponding prismatic joint at another side.

    Hybridglide

    HybridGlide

    Manipulator Creation and Analysis

    The Hybridglide mechanism consists of three actuated prismatic joints, in which two actuators are placed parallel and third one perpendicular to others two. Also the three bar links connected by spherical joints to the tool center point on one side and to the corresponding prismatic joint at another side.

    Triaglide

    TriaGlide

    Manipulator Creation and Analysis

    The Triaglide manipulator is driven by three actuated prismatic joints, in which all the three actuators parallel to each other and placed in the same plane. 

    UraneSX

    UraneSX

    Manipulator Creation and Analysis

    The UraneSX is similar to triaglide, but instead of three actuators in the same plane, they are placed in different planes.

    3RRR

    3RRR : NAVaRo

    Manipulator Creation and Analysis

  • PEER-REVIEWED PUBLICATIONS

    The 3-PPPS Parallel Robot with U-Shape Base, a 6-DOF Parallel Robot with Simple Kinematics​

    Abstract : One of the main problems associated with the use of 6 DOF parallel robots remains the solving of their kinematic models. This is rarely possible to analytically solve their models thereby justifying the application of numerical methods. These methods are difficult to implement in an industrial controller and can cause solution bifurcations close to singularities resulting in following an unplanned trajectory. Recently, a 3-PPPS robot with U-shaped base was introduced where an analytical kinematic model can be derived. Previously, quaternion parameters were used to represent the orientation of the mobile platform. To allow for simpler model handling, this article introduces the use of Euler angles which have a physical meaning for the users. Compact writing of the direct and inverse kinematic model is thus obtained. Using algebraic and cylindrical decomposition for the workspace, this provides a simpler representation of the largest domain without singularity around the “home” configuration.

     

    Damien Chablat, Luc Baron, Ranjan Jha, Luc Rolland. The 3-PPPS Parallel Robot with U-Shape Base, a 6-DOF Parallel Robot with simple Kinematics . Advances in Robot Kinematics 2018, Springer Proceedings in Advanced Robotics, Vol. 8, pp. 195-201, 2018. <Web Link>

    Workspace, joint space and singularities of a family of delta-like robot

    Abstract : This paper presents the workspace, the joint space and the singularities of a family of delta-like parallel robots by using algebraic tools. The different functions of SIROPA library are introduced, which is used to induce an estimation about the complexity in representing the singularities in the workspace and the joint space. A Gröbner based elimination is used to compute the singularities of the manipulator and a Cylindrical Algebraic Decomposition algorithm is used to study the workspace and the joint space. From these algebraic objects, we propose some certified three-dimensional plotting describing the shape of workspace and of the joint space which will help the engineers or researchers to decide the most suited configuration of the manipulator they should use for a given task. Also, the different parameters associated with the complexity of the serial and parallel singularities are tabulated, which further enhance the selection of the different configuration of the manipulator by comparing the complexity of the singularity equations.

     

    Ranjan Jha, Damien Chablat, Luc Baron, Fabrice Rouillier. Workspace, joint space and singularities of a family of delta-like robot. Mechanism and Machine Theory, Vol. 127, pp. 73-95, 2018. <Web Link>

    Influence of design parameters on the singularities and workspace of a 3-RPS Parallel Robot

    Abstract : This paper presents variations in the workspace, singularities, and joint space with respect to design parameter k, which is the ratio of the dimensions of the mobile platform to the dimensions of the base of a 3-RPS parallel manipulator. The influence of the design parameters on parasitic motion, which is important when selecting a manipulator for the desired task, is also studied. The cylindrical algebraic decomposition method and Gröbner-based computations are used to model the workspace and joint space with parallel singularities in 2R1T (two rotational and one translational) and 3T (three translational) projection spaces, where the orientation of the mobile platform is represented using quaternions. These computations are useful in selecting the optimum value for the design parameter k such that the parasitic motions can be limited to specific values. Three designs of the 3-RPS parallel robot, based on different values of k, are analyzed.

     

    Ranjan Jha, Damien Chablat, Luc Baron. Influence of design parameters on the singularities and workspace of a 3-RPS Parallel Robot. Transactions of the Canadian Society for Mechanical Engineering, 2018, 42(1): 30-37. <hal-01519620 Web Link>

    Kinematics and Workspace analysis of a 3PPPS Parallel Robot with U-Shaped Base

    Abstract : This paper presents the kinematic analysis of the 3-PPPS parallel robot with an equilateral mobile platform and a U-shape base. The proposed design and appropriate selection of parameters allow formulating simpler direct and inverse kinematics for the manipulator under study. The parallel singularities associated with the manipulator depend only on the orientation of the end-effector, and thus depend only on the orientation of the end effector. The quaternion parameters are used to represent the aspects, i.e. the singularity-free regions of the workspace. A cylindrical algebraic decomposition is used to characterize the workspace and joint space with a low number of cells. The discriminant variety is obtained to describe the boundaries of each cell. With these simplifications, the 3-PPPS parallel robot with proposed design can be claimed as the simplest 6 DOF robot, which further makes it useful for the industrial applications.

     

    Damien Chablat, Luc Baron, Ranjan Jha. Kinematics and Workspace analysis of a 3PPPS Parallel Robot with U-Shaped Base. International Design Engineering Technical Conferences & Computers and Information in Engineering Conference, Aug 2017, Cleveland, United States. 2017. <hal-01521850 Web Link>

    Influence of the trajectory planning on the accuracy of the Orthoglide 5-axis

    Abstract : Usually, the accuracy of parallel manipulators depends on the architecture of the robot, the design parameters, the trajec-tory planning and the location of the path in the workspace. This paper reports the influence of static and dynamic parameters in computing the error in the pose associated with the trajectory planning made and analyzed with the Orthoglide 5-axis. An error model is proposed based on the joint parameters (velocity and acceleration) and experimental data coming from the Orthoglide 5-axis. Newton and Gröbner based elimination methods are used to project the joint error in the workspace to check the accuracy/error in the Cartesian space. For the analysis, five similar trajectories with different locations inside the workspace are defined using fifth order polynomial equation for the trajectory planning. It is shown that the accuracy of the robot depends on the location of the path as well as the starting and the ending posture of the manipulator due to the acceleration parameters.

     

    Ranjan Jha, Damien Chablat, Fabrice Rouillier, Guillaume Moroz. Influence of the trajectory planning on the accuracy of theorthoglide 5-axis. ASME International Design Engineering Technical Conference and the Computer and Information in Engineering Conference (IDETC/CIE), Aug 2016, Charlotte, NC, United States. Proceedings of the ASME 2016 International Design Engineering Technical Conference and the Computer and Information in Engineering Conference (IDETC/CIE), 2016. <hal-01309190 Web Link>

    A Framework for the Control of a Parallel Manipulator with Several Actuation Modes

    Abstract : There have been several research works on reconfig-urable parallel manipulators in the last few years. Some robots are reconfigurable in the sense that the position of the anchor points on the moving platform or the actuated joints can be changed. Some problems may arise when one intends to make a prototype and develop its control scheme. A reconfigurable planar parallel robot, named NaVARo, is a 3-DOF planar parallel manipulator with eight actuation modes. The subject of this paper is about a control scheme of NaVARo while taking advantage of multiple sensors such as motor encoders, additional absolute encoders and magnetic sensors used to determine the current assembly mode of the manipulator. Finally, a methodology is presented to determine the home configuration of NaVARo.

     

    Damien Chablat, Ranjan Jha, Stéphane Caro. A Framework for the Control of a Parallel Manipulator with Several Actuation Modes. 14th International Conference on Industrial Informatics , Jul 2016, Poitiers, France. IEEE, 2016. <hal-01313376 Web Link>

    An algebraic method to check the singularity-free paths for parallel robots

    Abstract : Trajectory planning is a critical step while programming the parallel manipulators in a robotic cell. The main problem arises when there exists a singular configuration between the two poses of the end-effectors while discretizing the path with a classical approach. This paper presents an algebraic method to check the feasibility of any given trajectories in the workspace. The solutions of the polynomial equations associated with the tra-jectories are projected in the joint space using Gröbner based elimination methods and the remaining equations are expressed in a parametric form where the articular variables are functions of time t unlike any numerical or discretization method. These formal computations allow to write the Jacobian of the manip-ulator as a function of time and to check if its determinant can vanish between two poses. Another benefit of this approach is to use a largest workspace with a more complex shape than a cube, cylinder or sphere. For the Orthoglide, a three degrees of freedom parallel robot, three different trajectories are used to illustrate this method.

     

    Ranjan Jha, Damien Chablat, Fabrice Rouillier, Guillaume Moroz. An algebraic method to check the singularity-free paths for parallel robots. International Design Engineering Technical Conferences & Computers and Information in Engineering Conference, Aug 2015, Boston, United States. 2015. <hal-01142989 Web Link>

    Workspace and Singularity analysis of a Delta like family robot​

    Abstract : Workspace and joint space analysis are essential steps in describing the task and designing the control loop of the robot, respectively. This paper presents the descriptive analysis of a family of delta-like parallel robots by using algebraic tools to induce an estimation about the complexity in representing the singularities in the workspace and the joint space. A Gröbner based elimination is used to compute the singularities of the manipulator and a Cylindrical Algebraic Decomposition algorithm is used to study the workspace and the joint space. From these algebraic objects, we propose some certified three dimensional plotting describing the the shape of workspace and of the joint space which will help the engineers or researchers to decide the most suited configuration of the manipulator they should use for a given task. Also, the different parameters associated with the complexity of the serial and parallel singularities are tabulated, which further enhance the selection of the different configuration of the manipulator by comparing the complexity of the singularity equations.

     

    Ranjan Jha, Damien Chablat, Fabrice Rouillier, Guillaume Moroz. Workspace and Singularity analysis of a Delta like family robot. Robotics and Mechatronics, Springer, Vol. 37, Pp. 121 - 130, 2016. <hal-01142465 Web Link>

    Workspace and joint space analysis of the 3-RPS parallel robot​

    Abstract : The Accurate calculation of the workspace and joint space for 3 RPS parallel robotic manipulator is a highly addressed research work across the world. Researchers have proposed a variety of methods to calculate these parameters. In the present context a cylindrical algebraic decomposition based method is proposed to model the workspace and joint space. It is a well know feature that this robot admits two operation modes. We are able to find out the set in the joint space with a constant number of solutions for the direct kinematic problem and the locus of the cusp points for the both operation mode. The characteristic surfaces are also computed to define the uniqueness domains in the workspace. A simple 3-RPS parallel with similar base and mobile platform is used to illustrate this method.

     

    Damien Chablat, Ranjan Jha, Fabrice Rouillier, Guillaume Moroz. Workspace and joint space analysis of the 3-RPS parallel robot. ASME 2013 International Design Engineering Technical Conferences & Computers and Information in Engineering Conference, Aug 2014, Buffalo, United States. Volume 5A, pp.1-10, 2014. <hal-01006614 Web Link>

    Non-singular assembly mode changing trajectories in the workspace for the 3-RPS parallel robot​

    Abstract : Having non-singular assembly modes changing trajectories for the 3-RPS parallel robot is a well-known feature. The only known solution for defining such trajectory is to encircle a cusp point in the joint space. In this paper, the aspects and the characteristic surfaces are computed for each operation mode to define the uniqueness of the domains. Thus, we can easily see in the workspace that at least three assembly modes can be reached for each operation mode. To validate this property, the mathematical analysis of the determinant of the Jacobian is done. The image of these trajectories in the joint space is depicted with the curves associated with the cusp points.

     

    Damien Chablat, Ranjan Jha, Fabrice Rouillier, Guillaume Moroz. Non-singular assembly mode changing trajectories in the workspace for the 3-RPS parallel robot. Advances in Robot Kinematics, Springer, Pp. 149 - 159, 2014. <hal-00956325 Web Link>

    Implementation of motion transfer in robotic surgery

    Abstract : Minimally invasive surgery is a modern surgical technique in which the operating tools are inserted into the patient through small incisions. Robotic applications in general surgery have evolved from simple surgical assist devices, to more sophisticated systems capable of enhancing surgical performance. The primary class of robots used in general surgery today, are ‘master-slave’ machines, where the robot mimics the movement of the surgeon. A major drawback with the master-slave robotic systems is the motion coordination between the two. The paper discusses the techniques of motion transfer from master to slave and to implement force feedback from slave to master. Motion is transferred from master surgeon handle to the robotic arm depending on the encoder pulses from master configuration. The pulses from the encoder are processed and fed to the slave, which mimics the hand motion of master configuration. A two channel encoder with DC motor is used in master-slave configuration. The proposed configuration with force feedback capability enables the exact motion coordination between surgeon and robotic surgical system. This technique has a wide application, with accuracy, efficiency, safety and overall user experience that provide superior performance and reliability in master-slave robot-assisted interventions.

     

    Ranjan Jha, Varun Dhiman, Sanjeev Kumar, Amod Kumar. Implementation of motion transfer in robotic Surgery. Int. J. Medical Engineering and Informatics, Vol. 6, No. 4, pp. 289-296, 2014. [Web Link]

    Workspace analysis in the design parameter space of a 2-DOF spherical parallel mechanism for a prescribed workspace: Application to the otologic surgery

    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.

     

    Damien Chablat, Guillaume Michel, Philippe Bordure, Swaminath Venkateswaran, Ranjan Jha. Workspace analysis in the design parameter space of a 2-DOF spherical parallel mechanism for a prescribed workspace: Application to the otologic surgery. Mechanism and Machine Theory, Volume 157, 2021, 104224, ISSN 0094-114X, [Web Link]

    Stiffness Distribution of 3-RPS Parallel Manipulator Based on the Base-and-platform Configuration

    Abstract : Rehabilitation of ankle injuries must be under supervision of a therapist to prevent severe injuries. However, relying on a therapist is not consistent and accurate. In the present days, parallel manipulators play a key role as an ankle rehabilitation device to overcome the problem imposed by a therapist. The ankle rehabilitation device should be able to sustain the external forces and moments exerted from the patient’s feet. The external forces and moments applied to the platform can cause deflections, either translation or rotational deflections. These deflections depend mostly upon the stiffness properties of the device. The stiffness property is one of crucial factors to be considered in designing the ankle rehabilitation device. Therefore, this paper aims to analyse and establish the static and stiffness model of the 3-RPS parallel manipulator which is employed as an ankle rehabilitation device. Each RPS leg applies one constraint force and one actuation force intersecting the centre of spherical joint. By collecting all constraint forces and actuation forces, the Jacobian matrix can be formulated according to the Screw theory and Quaternion parameters. Influences of actuators and base-and-platform configuration are identified by using stiffness index, namely eigenvalues of the stiffness matrix. The base-and-platform configuration is described by the distance of each joint to the origin of coordinate frame and the angle among three legs. For given external wrenches, numerical simulations have been performed to determine the optimal distributions of actuators and base-and-platform configuration by taking into account the stiffness.

     

    Latifah Nurahmi, Rath Kautsar, Ranjan Jha. Stiffness Distribution of 3-RPS Parallel Manipulator Based on the Base-and-platform Configuration. In: Sen D., Mohan S., Ananthasuresh G. (eds) Mechanism and Machine Science. Lecture Notes in Mechanical Engineering. pp 57-68, Springer, Singapore. [Web Link]

    Real time implementation of motion transfer mechanism for master slave robotic configuration

    Abstract : Rehabilitation of ankle injuries must be under supervision of a therapist to prevent severe injuries. However, relying on a therapist is not consistent and accurate. In the present days, parallel manipulators play a key role as an ankle rehabilitation device to overcome the problem imposed by a therapist. The ankle rehabilitation device should be able to sustain the external forces and moments exerted from the patient’s feet. The external forces and moments applied to the platform can cause deflections, either translation or rotational deflections. These deflections depend mostly upon the stiffness properties of the device. The stiffness property is one of the crucial factors to be considered in designing the ankle rehabilitation device. Therefore, this paper aims to analyse and establish the static and stiffness model of the 3-RPS parallel manipulator which is employed as an ankle rehabilitation device. Each RPS leg applies one constraint force and one actuation force intersecting the center of spherical joint. By collecting all constraint forces and actuation forces, the Jacobian matrix can be formulated according to the Screw theory and Quaternion parameters. Influences of actuators and base-and-platform configuration are identified by using the stiffness index, namely eigenvalues of the stiffness matrix. The base-and-platform configuration is described by the distance of each joint to the origin of coordinate frame and the angle among three legs. Forgiven external wrenches, numerical simulations have been performed to determine the optimal distributions of actuators and base-and-platform configuration by taking into account the stiffness.

     

    Vikash Shaw, Parul Rani, Yogesh Kumar, Ranjan Jha, Dinesh Pankaj and Sanjeev Kumar. Real time implementation of motion transfer mechanism for master slave robotic configuration. 2019 3rd International Conference on Recent Developments in Control, Automation & Power Engineering (RDCAPE), 2019, pp. 390-394. [Web Link]

    Design and Development of finger probe for diagnosis of Anemia non-invasively

    Abstract : This present study describes the design of the finger probe to be working with near-infrared (NIR) and infrared (IR) light sources for the diagnosis of common blood disorder called as anemia non-invasively. The probe has been designed in 3D CAD system and fabricated with ABS plastic using Fortus 250mc 3D printer. In the probe the cushion has been used to provide comfort for the subject and flexibility to be used for all age groups of subjects (excluding children). The probe has been tested on multiple volunteers (male/female to record the neat and clean noise free photoplethysmographic (PPG) waveform. The output of the probe has been recorded using LabVIEW. The developed probe can be helpful to detect anemic conditions of the patient non-invasively which is a big concern now a days in society.

     

    Yogesh Kumar, Vikash Shaw, Parul Rani, Varun Dhiman, Ranjan Jha and Sanjeev Kumar. Design and Development of finger probe for diagnosis of Anemia non-invasively. 2019 3rd International Conference on Recent Developments in Control, Automation & Power Engineering (RDCAPE), 2019, pp. 384-389. [Web Link]

    Design and Development of finger probe for diagnosis of Anemia non-invasively

    Abstract : This present study describes the design of the finger probe to be working with near-infrared (NIR) and infrared (IR) light sources for the diagnosis of common blood disorder called as anemia non-invasively. The probe has been designed in 3D CAD system and fabricated with ABS plastic using Fortus 250mc 3D printer. In the probe the cushion has been used to provide comfort for the subject and flexibility to be used for all age groups of subjects (excluding children). The probe has been tested on multiple volunteers (male/female to record the neat and clean noise free photoplethysmographic (PPG) waveform. The output of the probe has been recorded using LabVIEW. The developed probe can be helpful to detect anemic conditions of the patient non-invasively which is a big concern now a days in society.

     

    Yogesh Kumar, Vikash Shaw, Parul Rani, Varun Dhiman, Ranjan Jha and Sanjeev Kumar. Design and Development of finger probe for diagnosis of Anemia non-invasively. 2019 3rd International Conference on Recent Developments in Control, Automation & Power Engineering (RDCAPE), 2019, pp. 384-389. [Web Link]

  • POSTERS

    A partition of the workspace and jointspace of parallel robots using algebraic tools

    Jha R., Chablat D., Rouillier F., Moroz G., “A partition of the workspace and jointspace of parallel robots using algebraic tools”, Applications of Parallel and Cable-driven Robots, INNOROBO, 2014. [WEB LINK]

     

    Force Feedback Approach In Implementation Of Haptics

    Jha R., Dhiman V., Kumar S. and Kumar A., “Force Feedback Approach In Implementation Of Haptics”, National Symposium on Instrumentation (NSI-37), CSIR-CSIO, India, 2012. [POSTER]

     

  • POSTDOC SUPERVISOR

    Prof. Luc Baron

    Professor and Director, Department of Mechanical Engineering

    École Polytechnique de Montréal
    Departement of Mechanical Engineering

    P.O. box 6079, station Centre-Ville

    Montréal, QC, CANADA H3C 3A7

    Phone: +1-514-340-4711 poste 4757 or 4744

    E-mail: Luc.Baron@polymtl.ca

    Web: www.professeurs.polymtl.ca/luc.baron

  • PHD THESIS SUPERVISORS

    cnrs

    Prof. Damien Chablat

    Research Director, CNRS, IRCCyN Nantes

    Institut de Recherche en Communications et Cybernétique de Nantes

    Ecole Centrale de Nantes  

    1 rue de la Noë, 44321 Nantes

    Phone: +33 2 40 37 69 48

    E-maildamien.chablat@cnrs.fr

    Web: www.irccyn.ec-nantes.fr/~chablat 

    inria

    Prof. Fabrice Rouillier

    Research Director, INRIA Paris

    Institut de Mathématiques de Jussieu
    Université Pierre et Marie Curie Paris VI
    4, place Jussieu, F-75005 Paris.

    Phone: +33 6 73 19 35 15

    E-mail: Fabrice.Rouillier@inria.fr

    Web: who.rocq.inria.fr/Fabrice.Rouillier/

    inria

    Dr. Guillaume Moroz

    INRIA Nancy-Grand Est

    615, rue du Jardin botanique

    54600, Nancy France

    Phone: +33 3 83 59 30 35

    E-mail: guillaume.moroz@inria.fr

    Web: www.loria.fr/~moroz/

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  • LOCATION

  • Contributions to the Performance Analysis of Parallel Robots

    Ph.D. Thesis : Ranjan JHA....... More details and Text Link

  • Motion Transfer and Haptics for Robotic Surgery

    Master Thesis : Ranjan JHA....... More details and Text Link

  • Influence of Design Parameters on the Singularities and Workspace of a 3-RPS Parallel Robot

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