Design and Development of a Novel 2-Degree-of-Freedom Parallel Robot

Robotica ◽  
2019 ◽  
Vol 38 (1) ◽  
pp. 1-14
Author(s):  
Changxi Cheng ◽  
Wenkai Huang ◽  
Chunliang Zhang

SummaryParallel robots are widely used in the fields of manufacturing, medical science, education, scientific research, etc. Many studies have been conducted on the topic already. However, shortcomings still exist, especially in certain situations. To meet the demand of good speed and load performances at the same time, this work presents a novel 2-degree-of-freedom parallel robot. The structural design, static, stiffness, and reachable workspace analysis of the robot are given in the manuscript. Experiment regarding the accuracy and speed performance is conducted, and the results are provided. In the end, potential applications of the proposed robot are suggested.

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Wen-ao Cao ◽  
Donghao Yang ◽  
Huafeng Ding

The umbrella linkage is one of the most classical deployable mechanisms. This paper concentrates on topological structural design of a family of umbrella-shaped deployable mechanisms based on new two-layer and two-loop spatial linkage units. First, deployable units are developed systematically from two-layer and two-loop linkage with four revolute pair (4R) coupling chains. Then, mobile connection modes of the deployable units are established based on the conditions of one degree-of-freedom (DOF) and structural symmetry. Finally, umbrella-shaped deployable mechanisms are constructed based on the developed deployable units and the established mobile connection modes. Like umbrellas, the designed deployable mechanisms can be actuated in a simple and reliable way, and those mechanisms have good potential applications in the fields of architecture, manufacturing, space exploration, and recreation.


Author(s):  
Jun-Mu Heo ◽  
Sung-hyun Choi ◽  
Kyoung-Su Park

Cable driven parallel robots (CDPRs) are a class of parallel robots in which the rigid links are replaced by cables. It consists of a moving end-effector and a number of active cables connected to the end-effector.


Author(s):  
Tahir Rasheed ◽  
Philip Long ◽  
David Marquez-Gamez ◽  
Stéphane Caro

Mobile Cable-Driven Parallel Robots (MCDPRs) are special type of Reconfigurable Cable Driven Parallel Robots (RCDPRs) with the ability of undergoing an autonomous change in their geometric architecture. MCDPRs consists of a classical Cable-Driven Parallel Robot (CDPR) carried by multiple Mobile Bases (MBs). Generally MCDPRs are kinematically redundant due to the additional mobilities generated by the motion of the MBs. As a consequence, this paper introduces a methodology that aims to determine the best kinematic redundancy scheme of Planar MCDPRs (PMCDPRs) with one degree of kinematic redundancy for pick-and-place operations. This paper also discusses the Static Equilibrium (SE) constraints of the PMCDPR MBs that are needed to be respected during the task. A case study of a PMCDPR with two MBs, four cables and a three degree-of-freedom (DoF) Moving Platform (MP) is considered.


Author(s):  
Saman Lessanibahri ◽  
Philippe Cardou ◽  
Stéphane Caro

Abstract This paper addresses the optimum design, configuration and workspace analysis of a Cable-Driven Parallel Robot with an embedded tilt-roll wrist. The manipulator is a hybrid robot consisting in an under-constrained moving-platform accommodating a tilt-roll wrist. The embedded wrist provides large amplitudes of tilt and roll rotations and a large translational workspace obtained by the moving-platform. This manipulator is suitable for tasks requiring large rotation and translation workspaces like tomography scanning, camera-orienting devices and visual surveillance. The moving-platform is an eight-degree-of-freedom articulated mechanism with large translational and rotational workspaces and it is suspended from a fixed frame by six cables. The manipulator employs two bi-actuated cables, i.e., cable loops to transmit the power from motors fixed on the ground to the tilt-roll wrist. Therefore, the manipulator achieves better dynamic performances due to a lower inertia of its moving-platform.


Author(s):  
Hamoon Hadian ◽  
Abbas Fattah

In this paper, the authors study the kinematic isotropic configuration of spatial cable-driven parallel robots by means of four different methods, namely, (i) symbolic method, (ii) geometric workspace, (iii) numerical workspace and global tension index (GTI), and (iv) numerical approach. The authors apply the mentioned techniques to two types of spatial cable-driven parallel manipulators to obtain their isotropic postures. These are a 6-6 cable-suspended parallel robot and a novel restricted three-degree-of-freedom cable-driven parallel robot. Eventually, the results of isotropic conditions of both cable robots are compared to show their applications.


Author(s):  
Hamoon Hadian ◽  
Abbas Fattah

In this paper, the authors study the kinematic isotropic configuration of spatial cable-driven parallel robots by means of four different methods, namely, (i) symbolic method, (ii) geometric workspace, (iii) numerical workspace and global tension index (GTI), and (iv) numerical approach. The authors apply the mentioned techniques to two types of spatial cable-driven parallel manipulators to obtain their isotropic postures. These are a 6-6 cable-suspended parallel robot and a novel restricted three-degree-of-freedom cable-driven parallel robot. Eventually, the results of isotropic conditions of both cable robots are compared to show their applications.


2018 ◽  
Vol 140 (9) ◽  
Author(s):  
Jokin Aginaga ◽  
Xabier Iriarte ◽  
Aitor Plaza ◽  
Vicente Mata

Rehabilitation robots are increasingly being developed in order to be used by injured people to perform exercise and training. As these exercises do not need wide range movements, some parallel robots with lower mobility architecture can be an ideal solution for this purpose. This paper presents the design of a new four degree-of-freedom (DOF) parallel robot for knee rehabilitation. The required four DOFs are two translations in a vertical plane and two rotations, one of them around an axis perpendicular to the vertical plane and the other one with respect to a vector normal to the instantaneous orientation of the mobile platform. These four DOFs are reached by means of two RPRR limbs and two UPS limbs linked to an articulated mobile platform with an internal DOF. Kinematics of the new mechanism are solved and the direct Jacobian is calculated. A singularity analysis is carried out and the gained DOFs of the direct singularities are calculated. Some of the singularities can be avoided by selecting suitable values of the geometric parameters of the robot. Moreover, among the found singularities, one of them can be used in order to fold up the mechanism for its transportation. It is concluded that the proposed mechanism reaches the desired output movements in order to carry out rehabilitation maneuvers in a singularity-free portion of its workspace.


2020 ◽  
Vol 12 (5) ◽  
Author(s):  
Zhaokun Zhang ◽  
Zhufeng Shao ◽  
Fazhong Peng ◽  
Haisheng Li ◽  
Liping Wang

Abstract Cable-driven parallel robots (CDPRs) have great prospects for high-speed applications because of their nature of low inertia and good dynamics. Existing high-speed CDPRs mainly adopt redundant cables to keep positive cable tensions. Redundant cables lead to complex and costly structure, and are likely to cause interference. In this study, a non-redundant CDPR for high-speed translational motions is designed with passive springs and parallel cables. First, the configuration of the CDPR is illustrated, and its kinematics and dynamics are studied. Then, the workspace of the CDPR is discussed in detail. The condition of positive cable tensions is proved. The influence of the springs’ layout on the workspace is analyzed. A method for determining the regular cylindrical operation workspace is proposed. Furthermore, the optimal design method for high-speed CDPRs with passive springs is developed. Performance indices for evaluating the force transmission are defined based on the matrix orthogonal degree. The geometric parameters are optimized based on the workspace and force transmission indices. The stiffness coefficient of the spring is determined based on the acceleration and cable tension requirements. Finally, the proposed CDPR and the traditional CDPR with redundant cables are compared through simulation. The results show that the designed CDPR possesses advantages in energy consumption and simple structure compared to CDPR with redundant cables.


2010 ◽  
Vol 166-167 ◽  
pp. 333-338
Author(s):  
Ciprian Rad ◽  
Calin Rusu ◽  
Radu Balan

This paper discusses the inverse and forward kinematics problem for a 2-dof parallel robot with actuator redundancy. The reachable workspace of the robot is generated for a set of parameters and a solution for the actuators is proposed in the final.


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