Workspace Analysis of a Three DOF Cable-Driven Mechanism

2009 ◽  
Vol 1 (4) ◽  
Author(s):  
Alireza Alikhani ◽  
Saeed Behzadipour ◽  
S. Ali Sadough Vanini ◽  
Aria Alasty
Keyword(s):  
Degrees Of Freedom ◽  
Large Scale ◽  
Parallel Robot ◽  
External Loading ◽  
Geometrical Shape ◽  
Geometrical Approach ◽  
Workspace Analysis ◽  
Tensile Forces ◽  
Rotational Motions ◽  
Three Degrees Of Freedom

A cable-driven mechanism based on the idea of BetaBot (2005, “A New Cable-Based Parallel Robot With Three Degrees of Freedom,” Multibody Syst. Dyn., 13, pp. 371–383) is analyzed and geometrical description of its workspace boundary is found. In this mechanism, the cable arrangement eliminates the rotational motions leaving the moving platform with three translational motions. The mechanism has potentials for large scale manipulation and robotics in harsh environments. A detailed analysis of the tensionable workspace of the mechanism is presented. The mechanism, in a tensionable position, can develop tensile forces in all cables to maintain its rigidity under arbitrary external loading. A set of conditions on the geometry of the mechanism is proposed for which the tensionable workspace becomes a well defined convex polyhedron. The geometrical shape of the workspace is then described and the tensionability of the mechanism inside the workspace is proved. The proof is quite general and based on a geometrical approach.

scholarly journals Automated Quality Assessment of Interferometric Ring Laser Data

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3425
Author(s):  
Andreas Brotzer ◽  
Felix Bernauer ◽  
Karl Ulrich Schreiber ◽  
Joachim Wassermann ◽  
Heiner Igel
Keyword(s):  
Quality Assessment ◽  
Ground Motion ◽  
Ring Laser ◽  
Degrees Of Freedom ◽  
Large Scale ◽  
Scientific Field ◽  
Optical Frequency ◽  
Laser Array ◽  
Laser Data ◽  
Rotational Motions

In seismology, an increased effort to observe all 12 degrees of freedom of seismic ground motion by complementing translational ground motion observations with measurements of strain and rotational motions could be witnessed in recent decades, aiming at an enhanced probing and understanding of Earth and other planetary bodies. The evolution of optical instrumentation, in particular large-scale ring laser installations, such as G-ring and ROMY (ROtational Motion in seismologY), and their geoscientific application have contributed significantly to the emergence of this scientific field. The currently most advanced, large-scale ring laser array is ROMY, which is unprecedented in scale and design. As a heterolithic structure, ROMY’s ring laser components are subject to optical frequency drifts. Such Sagnac interferometers require new considerations and approaches concerning data acquisition, processing and quality assessment, compared to conventional, mechanical instrumentation. We present an automated approach to assess the data quality and the performance of a ring laser, based on characteristics of the interferometric Sagnac signal. The developed scheme is applied to ROMY data to detect compromised operation states and assign quality flags. When ROMY’s database becomes publicly accessible, this assessment will be employed to provide a quality control feature for data requests.

Analysis and Optimization of a New Differentially Driven Cable Parallel Robot

2015 ◽  
Vol 7 (3) ◽  
Author(s):  
Hamed Khakpour ◽  
Lionel Birglen ◽  
Souheil-Antoine Tahan
Keyword(s):  
Kinematic Analysis ◽  
Design Methodology ◽  
Degrees Of Freedom ◽  
Parallel Robot ◽  
Cable Robot ◽  
Proper Design ◽  
Two Indices ◽  
Three Degrees Of Freedom ◽  
Cable Robots

In this paper, a new three degrees of freedom (DOF) differentially actuated cable parallel robot is proposed. This mechanism is driven by a prismatic actuator and three cable differentials. Through this design, the idea of using differentials in the structure of a spatial cable robot is investigated. Considering their particular properties, the kinematic analysis of the robot is presented. Then, two indices are defined to evaluate the workspaces of the robot. Using these indices, the robot is subsequently optimized. Finally, the performance of the optimized differentially driven robot is compared with fully actuated mechanisms. The results show that through a proper design methodology, the robot can have a larger workspace and better performance using differentials than the fully driven cable robots using the same number of actuators.

Kinematics and Workspace Analysis of 3-RPP Parallel Mechanism

2013 ◽  
Vol 456 ◽  
pp. 146-150
Author(s):  
Zhi Jiang Xie ◽  
Jun Zhang ◽  
Xiao Bo Liu
Keyword(s):  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Parallel Mechanisms ◽  
Vector Method ◽  
Workspace Analysis ◽  
Inverse Solutions ◽  
Three Degrees Of Freedom

This paper designed a kind of parallel mechanism with three degrees of freedom, the freedom and movement types of the robot are analyzed in detail, the parallel mechanisms Kinematics positive and inverse solutions are derived through using the vector method. And at last its workspace is analyzed and studied systematically.

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.

A novel 3-DOF translational parallel robot and its fuzzy controller design

2021 ◽  
pp. 1-14
Author(s):  
Tianxu Li ◽  
Mingde Gong ◽  
Kongming Hu ◽  
Lijuan Zhao ◽  
Baoqiang Zhao
Keyword(s):  
Pid Controller ◽  
Degrees Of Freedom ◽  
Fuzzy Controller ◽  
Controller Design ◽  
Screw Theory ◽  
Parallel Robot ◽  
Servo Control ◽  
Control Performance ◽  
Three Degrees Of Freedom ◽  
Better Than

In this paper, a novel three-degrees-of-freedom (3-DOF) parallel robot is designed, which can only move in three translational directions. It avoids the difficulty in the solution for forward kinematics of the parallel robot. The robot containing only lower pairs (P and R) has a simple mechanism. The characteristic that the parallel robot has only three translational degrees of freedom can be proved by the screw theory and the DOF can be got by the formula of calculating the DOF of space mechanism. The kinematics and workspace of the parallel robot is analyzed through calculation and simulation. In order to obtain better servo control performance, the PMSM fuzzy controller is designed. The analysis and simulation results show that the mechanism design of the parallel robot is reasonable, and the effect of fuzzy controller is better than the ordinary PID controller.

scholarly journals A Six Degree-of-Freedom Haptic Device Based on the Orthoglide and a Hybrid Agile Eye

2006 ◽  
Author(s):  
Damien Chablat ◽  
Philippe Wenger
Keyword(s):  
Degrees Of Freedom ◽  
Degree Of Freedom ◽  
Haptic Device ◽  
Parallel Mechanisms ◽  
Real Time Control ◽  
Time Control ◽  
Rotational Motions ◽  
Six Degree Of Freedom ◽  
Rotary Motor ◽  
Three Degrees Of Freedom

This paper is devoted to the kinematic design of a new six degree-of-freedom haptic device using two parallel mechanisms. The first one, called orthoglide, provides the translation motions and the second one, called agile eye, produces the rotational motions. These two motions are decoupled to simplify the direct and inverse kinematics, as it is needed for real-time control. To reduce the inertial load, the motors are fixed on the base and a transmission with two universal joints is used to transmit the rotational motions from the base to the end-effector. Two alternative wrists are proposed (i), the agile eye with three degrees of freedom or (ii) a hybrid wrist made by the assembly of a two-dof agile eye with a rotary motor. The last one is optimized to increase its stiffness and to decrease the number of moving parts.

Workspace Analysis of the 6 Degrees of Freedom PARTNER Parallel Robot

2010 ◽  
Vol 166-167 ◽  
pp. 155-160 ◽  
Author(s):  
Akos Csiszar ◽  
Cornel Brisan
Keyword(s):  
Degrees Of Freedom ◽  
Parallel Robot ◽  
Workspace Analysis ◽  
Modular Method ◽  
6 Degrees Of Freedom

This paper presents a modular method to compute the workspace of parallel robot with 6 degrees of freedom. For the generation of the workspace also the mechanical constrains of both the active and passive joints are taken into consideration.

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.

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