Research Projects

Kinematic and Dynamic Modeling of Parallel Mechanisms

Parallel Kinematic Mechanisms or Parallel robots are closed-loop mechanisms which offer several advantages in terms of better rigidity, higher precision and better dynamic performances compared to their serial counterpart. Due to the existence of multiple closed-loop chains, modeling parallel mechanisms are more complicated than serial mechanisms. During my master's studies, most of my research was dedicated to kinematic and dynamic modeling of parallel mechanisms.

Highlights:

  • We have modeled and analysed numerous parallel mechanisms with different motion patterns and architectures including: 2-DOF spherical parallel mechanism, Tripteron and Quadrupteron, Hexarot and Gantry-Tau.
  • By using a new geometric approach, inverse and forward kinematic problems were transformed to the problem of determining the intersection of basic geometric shapes. Compared to other proposed methods, this approach yields more compact and closed-form solutions.
  • The instantaneous kinematic problems were solved via employing the screw theory.
  • Different approaches such as Virtual Work and Newton–Euler were used for obtaining the inverse dynamic models.
  • By determining the base inertial parameters of the mechanisms a reduced dynamic model were obtained . As a result, while maintaining the accuracy, the computational time was reduced.
  • The mechanisms were also modeled and simulated in Simscape Multibody™ (formerly SimMechanics™) to verify the correctness of the derived models.


Related publications:

[1] Danaei, B., Arian, A., Masouleh, M.T. and Kalhor, A., 2017. "Dynamic modeling and base inertial parameters determination of a 2-DOF spherical parallel mechanism." Multibody System Dynamics, 41(4), pp.367-390. [PDF]

[2] Arian, A., Danaei, B. and Masouleh, M.T., 2016, October. "Kinematics and dynamics analysis of a 2-DOF spherical parallel robot." In Robotics and Mechatronics (ICROM), 2016 4th International Conference on (pp. 154-159). IEEE. [PDF]

[3] Danaei, B., Arian, A., Masouleh, M.T. and Kalhor, A., 2018. Kinematic and Dynamic Modeling and Base Inertial Parameters Determination of the Quadrupteron Parallel Manipulator. In Computational Kinematics (pp. 249-256). Springer, Cham. [PDF]

[4] Arian, A., Danaei, B. and Tale Masouleh, M., 2018. Kinematic and Dynamic Analyses of Tripteron, an Over-Constrained 3-DOF Translational Parallel Manipulator, through Newton-Euler Approach. AUT Journal of Modeling and Simulation, 50(1), pp.61-70. [PDF]

[5] Arian, A., Danaei, B., Abdi, H. and Nahavandi, S., 2017. Kinematic and dynamic analysis of the Gantry-Tau, a 3-DoF translational parallel manipulator. Applied Mathematical Modelling, 51, pp.217-231. [PDF]

[6] Pedrammehr, S., Danaei, B., Abdi, H., Masouleh, M.T. and Nahavandi, S., 2018. Dynamic analysis of Hexarot: axis-symmetric parallel manipulator. Robotica, 36(2), pp.225-240. [PDF]

[7] Arian, A., Danaei, B., Masouleh, M.T. and Kalhor, A., 2017, October. Dynamic Modeling and Base Inertial Parameters Determination of 3-DoF Planar Parallel Manipulator. In 2017 5th RSI International Conference on Robotics and Mechatronics (ICRoM) (pp. 546-551). IEEE. [PDF]

[8] Qazani, M.R.C., Pedrammehr, S., Rahmani, A., Danaei, B., Ettefagh, M.M., Rajab, A.K.S. and Abdi, H., 2015. Kinematic analysis and workspace determination of hexarot-a novel 6-DOF parallel manipulator with a rotation-symmetric arm system. Robotica, 33(8), pp.1686-1703. [PDF]

The designed 2-DOF spherical parallel mechanism at Human and Robot Interaction Laboratory (TaarLab), University of Tehran.

Two studied members of multipteron parallel mechanism family.

Gantry-Tau: 3-DoF parallel mechanism.

Hexarot: 6-DoF axis-symmetric parallel manipulator.

Model-based control of robotic systems

2-DoF Stabilizing Platform

The application of stabilization platform is to stabilize pointing direction of equipments, such as cameras, toward a specific object or direction by isolating the device from the mechanical disturbances made by the environment. In this project we have presented a 2-DoF gimbal system with parallel kinematic chain for the first time. Based on the derived kinematic model, three control algorithms of exponentially decay, full state feedback control, and sliding mode control are developed and validated by using simulation and experimental on board implementation.

Related publications:

[1] Danaei, B., Alipour, M., Arian, A., Masouleh, M.T. and Kalhor, A., 2017, October. Control of a two degree-of-freedom parallel robot as a stabilization platform. In 2017 5th RSI International Conference on Robotics and Mechatronics (ICRoM) (pp. 232-238). IEEE. [PDF]

Delta Robot

A Delta robot is a type of parallel mechanism that consists of three parallelogram arms which restrict the movement of the end-effector to pure translation. In this project, we designed and constructed a Delta robot and based on the kinematic model, a PID controller was developed and implemented on a PLC to control the robot.

Development of robotic hand SIMULATOR toolbox in simulink matlab

The Robotic Hand Simulator toolbox is developed for modeling and analyzing under-actuated robotic hands in Simulink Matlab.

This toolbox allows users to define hands with arbitrary structures and configurations. Also, physical contact between the robotic hand and external objects is modeled which could be used to evaluate the performance of the designed robotic hand and control algorithms for different tasks such as grasping and in-hand manipulation.

Development of a general approach for collision-free workspace determination

Obtaining collision-free workspace of robotic mechanical systems has been for a long time a challenging problem in designing a well- conditioned mechanism. In this research we developed a new general systematic approach using the so-called triangle-to-triangle intersection test in order to obtain the collision-free workspace of robotic mechanical systems.

In the proposed approach, a collision test is performed, based on the STL file, for all possible configurations of the robot which leads to obtain the collision-free workspace. This method provides a statistical data about the percentage of collision for each constituting part of the mechanism. By resorting to the latter statistical data, an index for collision-free workspace is introduced which provides some insights into designing a well-conditioned workspace in terms of mechanical interference. The approach is implemented on several mechanisms. This method could also be applied for collision-free motion planning purposes.


Related publications:

[1] Danaei, B., Karbasizadeh, N. and Masouleh, M.T., 2017. A general approach on collision-free workspace determination via triangle-to-triangle intersection test. Robotics and Computer-Integrated Manufacturing, 44, pp.230-241. [PDF]

An application of the proposed approach for collision-free motion planning a 3-RRR mechanism.