Modeling and stabilization of a cable-driven parallel platform suspended by an airship

2017 ◽  
Author(s):  
Fida Ben Abdallah ◽  
Naoufel Azouz ◽  
Lotfi Beji ◽  
Azgal Abichou
Keyword(s):  
Parallel Platform

A Low-Cost Hexa Platform for Efficient Force Control Systems Using Industrial Manipulators

2009 ◽  
Vol 147-149 ◽  
pp. 1-6 ◽  
Author(s):  
Rafal Osypiuk ◽  
Torsten Kröger
Keyword(s):  
Control Systems ◽  
Force Control ◽  
Execution Time ◽  
Low Cost ◽  
Degree Of Freedom ◽  
Industrial Manipulators ◽  
Control Concept ◽  
Six Dof ◽  
Parallel Platform ◽  
Six Degree Of Freedom

This contribution presents a new force control concept for industrial six-degree of freedom (DOF) manipulators, which uses a Hexa platform that provides an active environmental stiffness for all six DOFs. The paper focuses on the Hexa platform and is split into two essential parts: (i) parallel platform construction, and (ii) application of force control with industrial manipulators using a six-DOF environmental stiffness. This mechatronic solution almost gives one hundred percent robustness for stiffness changes in the environment, what guaranties a significant shortening of execution time.

Development of a Master-Slave Robotic System for MRI-Guided Intracardiac Interventions

2013 ◽  
Author(s):  
Amirhossein Salimi ◽  
Amin Ramezanifar ◽  
Javad Mohammadpour ◽  
Karolos M. Grogoriadis
Keyword(s):  
Magnetic Resonance Imaging ◽  
Pid Control ◽  
Control Design ◽  
Robotic System ◽  
Experimental Setup ◽  
Resonance Imaging ◽  
Parallel Platform ◽  
Mri Guided ◽  
Magnetic Resonance Imaging Mri ◽  
Reference Trajectories

Restricted space inside the magnetic resonance imaging (MRI) scanner bore prevents surgeons to directly interact with the patient during MRI-guided procedures. This motivates the development of a robotic system that can act as an interface during those interventions. In this paper, we present a master-slave robotic system as a solution to the aforedescribed issue. The proposed system consists of a commercial PHANTOM device (product of The Sensable Technologies) as the master robot and an MRI-compatible patient-mounted parallel platform (that we name ROBOCATH) designed to serve as the slave mechanism inside the scanner bore. We present in this paper the design principles for the platform, as well as the PID control design for the system. We use our experimental setup to evaluate the performance of the system by examining the effectiveness of the slave platform in tracking the reference trajectories generated by the master robot.

The Optimum Quality Index for the Stability of In-Parallel Planar Platform Devices

1999 ◽  
Vol 121 (1) ◽  
pp. 15-20 ◽  
Author(s):  
J. Lee ◽  
J. Duffy ◽  
M. Keler
Keyword(s):  
Optimal Design ◽  
Equilateral Triangle ◽  
Quality Index ◽  
Optimal Shape ◽  
Geometrical Meaning ◽  
Moving Platforms ◽  
Maximum Value ◽  
Dimensionless Ratio ◽  
Parallel Platform ◽  
The Stability

The paper investigates primarily the geometrical meaning of the determinant of the Jacobian (det j) of the three connector lines of a planar in-parallel platform device using reciprocity. A remarkably simple result is deduced: The maximum value of det j namely, det jm is simply one-half of the sum of the lengths of the sides of the moving triangular platform. Further, this result is shown to be independent of the location of the fixed pivots in the base. A dimensionless ratio λ = |det j|/det jm is defined as the quality index (0 ≤ λ ≤ 1) and it is proposed here to use it to measure “closeness” to a singularity. An example which determines the optimal design by comparing different shaped moving platforms having the same det jm is given and demonstrates that the optimal shape is in fact an equilateral triangle

Geometric Design of Symmetric 3-RRS Constrained Parallel Platforms

2004 ◽  
Author(s):  
Eric Wolbrecht ◽  
Hai-Jun Su ◽  
Alba Perez ◽  
J. Michael McCarthy
Keyword(s):  
Geometric Design ◽  
Homotopy Continuation ◽  
Total Degree ◽  
Polynomial Equations ◽  
Dimensional Synthesis ◽  
Kinematic Synthesis ◽  
Real Solutions ◽  
Parallel Platform ◽  
Three Degree Of Freedom ◽  
Serial Chains

The paper presents the kinematic synthesis of a symmetric parallel platform supported by three RRS serial chains. The dimensional synthesis of this three degree-of-freedom system is obtained using design equations for each of three RRS chains obtained by requiring that they reach a specified set of task positions. The result is 10 polynomial equations in 10 unknowns, which is solved using polynomial homotopy continuation. An example is provided in which the direction of the first revolute joint (2 parameters) and the z component of the base and platform are specified as well as the two task positions. The system of polynomials has a total degree of 4096 which means that in theory it can have as many solutions. Our example has 70 real solutions that define 70 different symmetric platforms that can reach the specified positions.

A New Approach to Type Synthesis of Spatial Robotic Mechanisms

1992 ◽  
Author(s):  
Akhtar N. Malik ◽  
D. R. Kerr
Keyword(s):  
Robot Manipulators ◽  
Sufficient Conditions ◽  
Necessary And Sufficient Conditions ◽  
Type Synthesis ◽  
End Effector ◽  
New Approach ◽  
Parallel Platform ◽  
Necessary And Sufficient

Abstract This paper presents a new approach for carrying out the type synthesis of spatial parallel platform-type mechanisms, used as robot manipulators. It takes into account the total mobility of the system and the partial mobility of its sub-mechanisms. The paper also provides the necessary and sufficient conditions for the mechanisms to function with specified end-effector freedoms, which are described in two theorems. The total number of possible mechanisms with given mobility and structure are tabulated. The work is based on a modified Grübler mobility criterion and also on the consideration of kinematic restraints.

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