TO STUDY AND DEVELOP A PROTOTYPE MODEL OF
PARALLEL MANIPULATORS
M.Muralidhar

Outline:
• Abstract
• Introduction
• Literature Review
• Advantages
• Applications
• References

ABSTRACT:
Parallel manipulators increase quality because of their large payload
carrying capacity, high stiffness, high accuracy and good precision in
positioning. Several parallel manipulators with 6-degree of freedom were
developed. But 6 dof manipulators have complicated analysis and moreover
distinct applications requires less then 6 -dof such as surgical manipulators,
3 -dof are flight simulations, etc. Parallel manipulators like 3-dof, 4-dof or
may be 5-dof.
A intended position analysis of spatial parallel manipulator consists
of 3-6 identical limbs , Base platform, Mobile platform, revolute joints,
prismatic joints and spherical joints. In the present task intended to carry
out, the positional analysis of spatial parallel manipulators have to be
analyzed. All the possible solutions of this initial analysis are calculated by
changing the limb lengths through linear actuators. modeling and
simulation done in Catia.

• INTRODUCTION:
* Spatial multi-degree of freedom mechanisms
*The motion characteristics may be planar, spherical [or] special type .
*The kinematic structure is made up of a closed loop mechanism.
* Each joint must be revolute [R] or prismatic[P] and mobility of each joint
must be one.
* 6 Dof parallel manipulators such as Stewart – Gough platform type and
Stewart universal type test machines

•
Stewart platform is six degree of freedom parallel mechanisms that consists of rigid
body moving plate, connected to fixed base plate through six independent kinematic
legs.
• Each leg contain precision ball-screw assembly and a DC-motor. Thus, length of the legs
is variable and they can be controlled separately to perform the motion of the moving
platform

• Positional analysis
o Kinematic analysis
a) forward kinematics
• b) inverse kinematics
Dynamic analysis
a) forward Dynamics
b) inverse Dynamics

:literature review
• Nalluri Mohan Rao and Mallikarjuna Rao R F (2006) “ Multi Dimensional
Synthesis of spatial 3-RPS Parallel Manipulators “, In this work the inverse
kinematics solutions are derived from the closed form . All possible solutions of
this initial analysis are calculated by change in limb lengths through linear
actuators, and also position and orientation equations of mobile platform with
respect to fixed base platform are analyzed.
• Stewart D ‘ A Platform with six Degree of Freedom ‘ says that describes a
mechanism which has six degrees of freedom, controlled in any combination by
six motors, each having a ground abutment. It is considered that by its
particular arrangement, this mechanism may form an elegant design for
simulating flight conditions in the training of pilots. Unlike most simulators, it
has no fixed axes relative to the ground, and therefore within the limits of
amplitude of the design it can truly simulate the conditions of banking by
carrying the simulation of control surfaces into the axes of the new attitude.

• Khalid ali Abdelaziz and Yung liu studied to find the limb
lengths of 3 Dof parallel manipulators can be found by using
Matlab coding to solve the non linear equations using inverse
kinematics and position analysis of also donethe 3 dof parallel
manipulator.

• Lee Kand shah D K , “Kinematic Analysis of a Three Degree of
Freedom In – parallel Activated Manipulator “, this work
studied forward and inverse kinematics of parallel
manipulators .
• Lee Kand shah D K , “Dynamic Analysis of a Three Degree of
Freedom In – parallel Activated Manipulator “, this work
studied dynamic analysis of parallel manipulators to control
the movement of the limbs.

• Xiaoyong Wu , Zhijiang Xie jorgen Asboll Kepler work presents model 3PPR Plane
parallel mipulators, aiming to optimize the shape design of the base and moving
platform. A case study included to demonstrate the dynamic performance with an
optimal performance shape design.
• Selcuk Kizir and zafer Bingul study indicates a high precision 6 DOF Stewart platform
is controlled by a PID and sliding mode controller . These controllers are embeded in a
Dspace DS1103 real time controller which is programmable in the Simulink
environment this study can be an example shows that how a real time controller can be
developed by using Matlab / Simulink and Dspace DS1103.if non linear extenal forces
applied to moving platform, control performance of the SMC will be better then PID.

ADVANTAGES
• Parallel manipulators are high stiffness
• high accuracy
• High speed
• Low inertia
• Large payload carrying capacity
• Good precision in positioning

APPLICATIONS:
• Parallel manipulators are such as airplane simulators
• Mining machines
• Walking machines
• Adjustable articulated trusses
• Pointing devices
• Robot manipulators
• Micro manipulators
• Tunnel borer
• Barbette of warship

• Satellite surveillance platform
• Parallel machine tools surgical manipulators
• Three degree of freedom sensors
• Medical applications
• Industrial applications

REFERENCES
• Lee K and Shah D K (1987) “Kinematic Analysis of a Three Degree Freedom In – Parallel Manipulators
“,in proceedings of the IEEE International Conference on Robotics and Automation, Vol.1,pp.345-350
• Lee K and Shah D K (1987) “Dynamic Analysis of a Three Degree Freedom In – Parallel Manipulators “,
IEEE Trans. Rob. Autom., Vol.4,pp.361-367
• Nalluri Mohan Rao K and Mallikarjuna rao RF (2006) “ Dimensional Synthesis of Spacial 3-RPS Parallel
manipulator for a Prescribed range of motion of Spherical joints “, J.nof Mechanisms of Machne
theory, vol.125,pp.447-486.
• Nalluri Mohan Rao K and Mallikarjuna rao RF (2006) “Multi – position Dimensional Synthesis of
Spacial 3-RPS Parallel manipulator for a Prescribed range of motion of Spherical joints “, J.nof
Mechanisms of Machne theory, vol.128,pp.815-819
• Stewart D (1965) .”A Platform with Six Degree of freedom”, Proc.inst.mech . Engg
,vol.180,NO.15,pp.371-386
• Younong Gong “ Design Analysis of a Stewart Platform for Vehicle Emulator Systems”
Massachusetts Institute of technology

• Xiaoyong Wu , Zhijiang Xie , Jorgen Asbol Kepler Shoping Bai work A Parametric model of 3 PPR
planar parallel manipulators for optimum shape design of platform
• Yangmin li and Qingsong Xu R F (2006), “Kinematic Analysis and Design of a New 3-Dof Translational
Parallel Manipulator”.J.of ASME,vol128,pp.729-737.
• Yuefa Fang and Lung –Wen Tsai R F (2004) , “structural synthesis of a class of 3-dof Rotational Parallel
Manipulaters”,J.OF IEEE,vol.20,pp.117-121.

Thank You