scholarly journals Modeling and Control of a Cable-Suspended Sling-Like Parallel Robot for Throwing Operations

2020 ◽  
Vol 10 (24) ◽  
pp. 9067
Author(s):  
Deng Lin ◽  
Giovanni Mottola ◽  
Marco Carricato ◽  
Xiaoling Jiang
Keyword(s):  
Mathematical Models ◽  
Degrees Of Freedom ◽  
Parallel Robot ◽  
Parallel Robots ◽  
Target Point ◽  
Inertial Effects ◽  
End Effector ◽  
Modeling And Control ◽  
And Control ◽  
Three Degrees Of Freedom

Cable-driven parallel robots can provide interesting advantages over conventional robots with rigid links; in particular, robots with a cable-suspended architecture can have very large workspaces. Recent research has shown that dynamic trajectories allow the robot to further increase its workspace by taking advantage of inertial effects. In our work, we consider a three-degrees-of-freedom parallel robot suspended by three cables, with a point-mass end-effector. This model was considered in previous works to analyze the conditions for dynamical feasibility of a trajectory. Here, we enhance the robot’s capabilities by using it as a sling, that is, by throwing a mass at a suitable time. The mass is carried at the end-effector by a gripper, which releases the mass so that it can reach a given target point. Mathematical models are presented that provide guidelines for planning the trajectory. Moreover, results are shown from simulations that include the effect of cable elasticity. Finally, suggestions are offered regarding how such a trajectory can be optimized.

scholarly journals Rotational Workspace Expansion of a Planar CDPR with a Circular End-Effector Mechanism Allowing Passive Reconfiguration

Robotics ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 57 ◽  
Author(s):  
Marco Carpio Alemán ◽  
Roque Saltaren ◽  
Alejandro Rodriguez ◽  
Gerardo Portilla ◽  
Juan Placencia
Keyword(s):  
Degrees Of Freedom ◽  
Parallel Robot ◽  
Parallel Robots ◽  
End Effector ◽  
Effector Mechanism ◽  
Circular Structure ◽  
Adams Software ◽  
Anchor Points ◽  
Orientation Workspace ◽  
Three Degrees Of Freedom

Cable-Driven Parallel Robots (CDPR) operate over a large positional workspace and a relatively large orientation workspace. In the present work, the expansion of the orientation Wrench Feasible Workspace (WFW) in a planar four-cable passive reconfigurable parallel robot with three degrees of freedom was determined. To this end, we proposed a circular-geometry effector mechanism, whose structure allows automatic mobility of the two anchor points of the cables supporting the End Effector (EE). The WFW of the proposed circular structure robot was compared with that of a traditional robot with a rectangular geometry and fixed anchor points. Considering the feasible geometric and tension forces on the cables, the generated workspace volume of the robot was demonstrated in an analysis-by-intervals. The results were validated by simulating the orientation movements of the robot in ADAMS software and a real experimental test was developed for a hypothetical case. The proposed design significantly expanded the orientation workspace of the robot. The remaining limitation is the segment of the travel space in which the mobile connection points can slide. Overcoming this limitation would enable the maximum rotation of the EE.

Modelling and Simulation of a Isoglide T3R1 Parallel Robot

2010 ◽  
Vol 166-167 ◽  
pp. 457-462
Author(s):  
Dan Verdes ◽  
Radu Balan ◽  
Máthé Koppány
Keyword(s):  
High Speed ◽  
Degrees Of Freedom ◽  
Parallel Robot ◽  
Parallel Robots ◽  
Practical Implementation ◽  
Medical Robots ◽  
The Past ◽  
And Control ◽  
Workspace Design ◽  
Human Systems

Parallel robots find many applications in human-systems interaction, medical robots, rehabilitation, exoskeletons, to name a few. These applications are characterized by many imperatives, with robust precision and dynamic workspace computation as the two ultimate ones. This paper presents kinematic analysis, workspace, design and control to 3 degrees of freedom (DOF) parallel robots. Parallel robots have received considerable attention from both researchers and manufacturers over the past years because of their potential for high stiffness, low inertia and high speed capability. Therefore, the 3 DOF translation parallel robots provide high potential and good prospects for their practical implementation in human-systems interaction.

Experimental results for the flexible joint cable-suspended manipulator of ICaSbot

Robotica ◽  
2013 ◽  
Vol 31 (6) ◽  
pp. 887-904 ◽  
Author(s):  
M. H. Korayem ◽  
M. Bamdad ◽  
H. Tourajizadeh ◽  
A. H. Korayem ◽  
R. M. Zehtab ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Experimental Tests ◽  
Parallel Robot ◽  
Joint Space ◽  
End Effector ◽  
Flexible Joint ◽  
Cable Robot ◽  
Six Dof ◽  
And Control ◽  
Computed Torque

SUMMARYIn this paper, design, dynamic, and control of the motors of a spatial cable robot are presented considering flexibility of the joints. End-effector control in order to control all six spatial degrees of freedom (DOFs) of the system and motor control in order to control the joints flexibility are proposed here. Corresponding programing of its operation is done by formulating the kinematics and dynamics and also control of the robot. Considering the existence of gearboxes, flexibility of the joints is modeled in the feed-forward term of its controller to achieve better accuracy. A two sequential closed-loop strategy consisting of proportional derivative (PD) for linear actuators in joint space and computed torque method for nonlinear end-effector in Cartesian space is presented for further accuracy. Flexibility is estimated using modeling and simulation by MATLAB and SimDesigner. A prototype has been built and experimental tests have been done to verify the efficiency of the proposed modeling and controller as well as the effect of flexibility of the joints. The ICaSbot (IUST Cable-Suspended robot) is an under-constrained six-DOF parallel robot actuated by the aid of six suspended cables. An experimental test is conducted for the manufactured flexible joint cable robot of ICaSbot and the outputs of sensors are compared with simulation. The efficiency of the proposed schemes is demonstrated.

Dynamic Trajectory Planning for a Three Degrees-of-Freedom Cable-Driven Parallel Robot Using Quintic B-Splines

2020 ◽  
Vol 142 (7) ◽  
Author(s):  
Sen Qian ◽  
Kunlong Bao ◽  
Bin Zi ◽  
W. D. Zhu
Keyword(s):  
Trajectory Planning ◽  
Degrees Of Freedom ◽  
Parallel Robot ◽  
Planning Method ◽  
End Effector ◽  
B Spline ◽  
B Splines ◽  
Pick And Place ◽  
Two Factors ◽  
Three Degrees Of Freedom

Abstract This paper presents a new trajectory planning method based on the improved quintic B-splines curves for a three degrees-of-freedom (3-DOF) cable-driven parallel robot (CDPR). First, the conditions of positive cables’ tension are expressed in terms of the position and acceleration constraints of the end-effector. Then, an improved B-spline curve is introduced, which is employed for generating a pick-and-place path by interpolating a set of given via-points. Meanwhile, by expressing the position and acceleration of the end-effector in terms of the first and second derivatives of the improved B-spline, the cable tension constraints are described in the form of B-spline parameters. According to the properties of the defined pick-and-place path, the proposed motion profile is dominated by two factors: the time taken for the end-effector to pass through all the via-points and the ratio between the nodes of B-spline. The two factors are determined through multi-objective optimization based on the efficiency coefficient method. Finally, experimental results on a 3-DOF CDPR show that the improved B-spline exhibits overall superior behavior in terms of velocity, acceleration, and cables force compared with the traditional B-spline. The validity of the proposed trajectory planning method is proved through the experiments.

DeltaBot: A New Cable-Based Ultra High Speed Robot

2003 ◽  
Author(s):  
Saeed Behzadipour ◽  
Robert Dekker ◽  
Amir Khajepour ◽  
Edmon Chan
Keyword(s):  
High Speed ◽  
Degrees Of Freedom ◽  
Manufacturing Industry ◽  
Design Procedure ◽  
Parallel Manipulators ◽  
Parallel Robot ◽  
Parallel Robots ◽  
Manufacturing Cost ◽  
End Effector ◽  
Serial Manipulators

The growing needs for high speed positioning devices in the automated manufacturing industry have been challenged by robotic science for more than two decades. Parallel manipulators have been widely used for this purpose due to their advantage of lower moving inertia over the conventional serial manipulators. Cable actuated parallel robots were introduced in 1980’s to reduce the moving inertia even further. In this work, a new cable-based parallel robot is introduced. For this robot, the cables are used not only to actuate the end-effector but also to apply the necessary kinematic constraints to provide three pure translational degrees of freedom. In order to maintain tension in the cables, a passive air cylinder is used to push the end-effector against the stationary platform. In addition to low moving inertia, the new design benefits from simplicity and low manufacturing cost by eliminating joints from the robot’s mechanism. The design procedure and the results of experiments will be discussed in the following.

Fuzzy Control of a Pneumatic Muscle Driven Parallel Robot for Ankle Rehabilitation

2009 ◽  
Author(s):  
Prashant K. Jamwal ◽  
Shane Xie ◽  
Jack Farrant
Keyword(s):  
Fuzzy Control ◽  
Degrees Of Freedom ◽  
Fuzzy Controller ◽  
Parallel Robot ◽  
Modeling And Control ◽  
Pneumatic Muscle ◽  
Linear Behavior ◽  
Improved Performance ◽  
Unpredictable Environment ◽  
And Control

A new wearable parallel robot has been designed and constructed for ankle joint rehabilitation treatments. The robot employs four pneumatic muscle actuators (PMA) together with cables to achieve three rotational degrees of freedom (dof) of its end platform. Parallel topology of the robot, unpredictable environment along with the time varying and non-linear behavior of actuators impose modeling and control challenges which are difficult to comprehend. In this paper an optimal fuzzy dynamic model of the pneumatic muscle has been developed to accurately predict the muscle behavior. The model is capable of mapping the complex relationship in length, force and pressure of the PMA with higher accuracy. This model has been further used to develop a fuzzy control scheme for the ankle robot. Experimental results are obtained to study and model the simultaneous actuation of all the actuators. Comparison with the previous dynamic modeling and control schemes demonstrates an improved performance of the proposed fuzzy controller.

The QuadroG Robot, a Parallel Robot With a Configurable Platform for Haptic Applications

2015 ◽  
Author(s):  
Salua Hamaza ◽  
Patrice Lambert ◽  
Marco Carricato ◽  
Just Herder
Keyword(s):  
Kinematic Analysis ◽  
Degrees Of Freedom ◽  
Closed Loop ◽  
Parallel Robot ◽  
Parallel Robots ◽  
End Effector ◽  
Contact Points ◽  
Loop Chain ◽  
End Effectors ◽  
4 Degrees Of Freedom

This paper explores the fundamentals of parallel robots with configurable platforms (PRCP), as well as the design and the kinematic analysis of those. The concept behind PRCP is that the rigid (non-configurable) end-effector is replaced by a closed-loop chain, the configurable platform. The use of a closed-loop chain allows the robot to interact with the environment from multiple contact points on the platform, which reflects the presence of multiple end-effectors. This results in a robot that successfully combines motion and grasping capabilities into a structure that provides an inherent high stiffness. This paper aims to introduce the QuadroG robot, a 4 degrees of freedom PRCP which finely merges planar motion together with grasping capabilities.

scholarly journals Modal Control for Active Vibration Damping of Cable-Driven Parallel Robots

2020 ◽  
Vol 12 (5) ◽  
Author(s):  
Loïc Cuvillon ◽  
Xavier Weber ◽  
Jacques Gangloff
Keyword(s):  
Degrees Of Freedom ◽  
Transfer Functions ◽  
Parallel Robot ◽  
Vibration Damping ◽  
Parallel Robots ◽  
Robot Dynamics ◽  
End Effector ◽  
Active Vibration Damping ◽  
Active Vibration ◽  
High Dynamics

Abstract Cable-driven parallel robots are well suited for applications that require a very large workspace. Thanks to their lightweight moving parts, they can achieve high dynamics while remaining pretty safe for nearby human workers. Furthermore, their size depends only on the length of the cables; thus, their scale is almost totally decoupled from their cost. However, due to the cables, the stiffness is very low with respect to rigid link robots, inducing slowly damped oscillations of the end effector. Previous works have shown that those vibrations can be effectively damped by the winch actuators thanks to active vibration damping techniques. In this paper, a gain scheduling approach is proposed based on a linearized model of the robot dynamics. This model is projected in the modal space yielding six decoupled transfer functions for six degrees-of-freedom (DoFs) of a cable-driven parallel robot using thin cables. The stability of the proposed control law is analyzed for a static and a moving end effector. The proposed control algorithm is validated experimentally on an eight-cable suspended robot prototype.

scholarly journals Design and implementation of a multi-degrees-of-freedom cable-driven parallel robot with gripper

2018 ◽  
Vol 15 (5) ◽  
pp. 172988141880384 ◽  
Author(s):  
Jonqlan Lin ◽  
Chi Ying Wu ◽  
Julian Chang
Keyword(s):  
Degrees Of Freedom ◽  
Load Capacity ◽  
Kinematic Model ◽  
Weight Ratio ◽  
Parallel Robot ◽  
Parallel Robots ◽  
Control Mode ◽  
Level Control ◽  
End Effector ◽  
Upper Level

Cable-driven parallel robots comprise driven actuators that allow controlled cables to act in parallel on an end-effector. Such a robotic system has a potentially large reachable workspace, large load capacity, high payload-to-weight ratio, high reconfigurability, and low inertia, relative to rigid link serial and parallel robots. In this work, a multi-degrees-of-freedom cable-suspended robot that can carry out pick-and-place tasks in large workspaces with heavy loads is designed. The proposed cable-driven parallel robot is composed of a rigid frame and an end-effector that is suspended from eight cables—four upper cables and four lower cables. The lengths of the cables are computed from the given positions of the suspended end-effector using a kinematic model. However, most multi-cable-driven robots suffer from interference among the cables, requiring a complex control methodology to find a target goal. Owing to this issue with cable-driven parallel robots, the whole control structure decomposes positioning control missions and allocates them into upper level and lower level. The upper level control is responsible for tracking the suspended end-effector to the target region. The lower level control makes fine positional modifications. Experimental results reveal that the hybrid control mode notably improves positioning performance. The wide variety of issues that are considered in this work apply to aerostats, towing cranes, locomotion interfaces, and large-scale manufacturing that require cable-driven parallel robots.

scholarly journals An Algebraic Method to Check the Singularity-Free Paths for Parallel Robots

2015 ◽  
Author(s):  
R. Jha ◽  
D. Chablat ◽  
F. Rouillier ◽  
G. Moroz
Keyword(s):  
Degrees Of Freedom ◽  
Complex Shape ◽  
Algebraic Method ◽  
Parallel Manipulators ◽  
Parallel Robot ◽  
Joint Space ◽  
Parallel Robots ◽  
Singular Configuration ◽  
End Effectors ◽  
Three Degrees Of Freedom

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 trajectories 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 manipulator 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.

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