scholarly journals Structural-Parametric Synthesis of the RoboMech Class Parallel Mechanism with Two Sliders

2021 ◽  
Vol 11 (21) ◽  
pp. 9831
Author(s):  
Zhumadil Baigunchekov ◽  
Med Amine Laribi ◽  
Giuseppe Carbone ◽  
Azamat Mustafa ◽  
Bekzat Amanov ◽  
...  

This paper addresses the structural-parametric synthesis and kinematic analysis of the RoboMech class of parallel mechanisms (PM) having two sliders. The proposed methods allow the synthesis of a PM with its structure and geometric parameters of the links to obtain the given laws of motions of the input and output links (sliders). The paper outlines a possible application of the proposed approach to design a PM for a cold stamping technological line. The proposed PM is formed by connecting two sliders (input and output objects) using one passive and one negative closing kinematic chain (CKC). The passive CKC does not impose a geometric constraint on the movements of the sliders and the geometric parameters of its links are varied to satisfy the geometric constraint of the negative CKC. The negative CKC imposes one geometric constraint on the movements of the sliders and its geometric parameters are determined on the basis of the Chebyshev and least-square approximations. Problems of positions and analogues of velocities and accelerations of the considered PM are solved to demonstrate the feasibility and effectiveness of the proposed formulations and case of study.

Author(s):  
Duanling Li ◽  
Pu Jia ◽  
Jiazhou Li ◽  
Dan Zhang ◽  
Xianwen Kong

Abstract The current research of reconfigurable parallel mechanism mainly focuses on the construction of reconfigurable joints. Compared with the method of changing the mobility by physical locking joints, the geometric constraint has good controllability, and the constructed parallel mechanism has more configurations and wider application range. This paper presents a reconfigurable axis (rA) joint inspired and evolved from Rubik's Cubes, which have a unique feature of geometric and physical constraint of axes of joint. The effectiveness of the rA joint in the construction of the limb is analyzed, resulting in a change in mobility and topology of the parallel mechanism. The rA joint makes the angle among the three axes inside the groove changed arbitrarily. This change in mobility is completed by the case illustrated by a 3(rA)P(rA) reconfigurable parallel mechanism having variable mobility from 1 to 6 and having various special configurations including pure translations, pure rotations. The underlying principle of the metamorphosis of this rA joint is shown by investigating the dependence of the corresponding screw system comprising of line vectors, leading to evolution of the rA joint from two types of spherical joints to three types of variable Hooke joints and one revolute joint. The reconfigurable parallel mechanism alters its topology by rotating or locking the axis of rA joint to turn all limbs into different phases. The prototype of reconfigurable parallel mechanism is manufactured and all configurations are enumerated to verify the validity of the theoretical method by physical experiments.


Robotics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 99
Author(s):  
Zhumadil Baigunchekov ◽  
Med Amine Laribi ◽  
Azamat Mustafa ◽  
Abzal Kassinov

In this paper, methods of kinematic synthesis and analysis of the RoboMech class parallel manipulator (PM) with two grippers (end effectors) are presented. This PM is formed by connecting two output objects (grippers) with a base using two passive and one negative closing kinematic chains (CKCs). A PM with two end effectors can be used for reloading operations of stamped products between two adjacent main technologies in a cold stamping line. Passive CKCs represent two serial manipulators with two degrees of freedom, and negative CKC is a three-joined link with three negative degrees of freedom. A negative CKC imposes three geometric constraints on the movements of the two output objects. Geometric parameters of the negative CKC are determined on the basis of the problems of the Chebyshev and least-square approximations. Problems of positions and analogues of velocities and accelerations of the PM with two end effectors have been solved.


1999 ◽  
Author(s):  
Luc H. Rolland

Abstract Two novel 4-DOF very fast parallel robots were designed. This paper introduces the new parallel mechanism designs which are named the Manta and the Kanuk. In order to reduce manipulator overall costs, the actuator and encoder numbers are minimized to the exact effective degrees-of-freedoms (DOF) which is usually not the case in most parallel robot designs. The robots allow end-effector displacements along the three Cartesian translations and one platform transversal rotation. The two remaining rotations are blocked by the intrinsic mechanical structure including the rotation along the platform normal which is always limited in range. The main advantages are high stiffness through the multiple kinematic chain structure which allow for low mass designs. Moreover, they feature simple mechanical construction. Thus, it shall be possible to achieve very high throughput since high accelerations are feasible. To circumvent the known workspace limitations, the actuators were selected to be prismatic along linear axes. The applications are automated warehouse manipulation, mediatheque manipulation, machine tool tool changers, loading and unloading.


2012 ◽  
Vol 135 (1) ◽  
Author(s):  
Ketao Zhang ◽  
Jian S. Dai ◽  
Yuefa Fang

This paper presents a unique feature of geometric constraint of adjacent axes of the variable-axis (vA) joint and analyses the effectiveness in the constructed limb, resulting in variation of mobility configuration of two 3SvPSv metamorphic parallel mechanisms. The underlying principle of the metamorphosis of this vA joint is unravelled by investigating the dependence of the corresponding screw system comprising of line vectors, leading to evolution of the vA joint from the source phase Sv to the variable Hooke’s joint phase Uv and the variable revolute-joint phase Rv. The kinematic chain installed with the vA joint forms a reconfigurable limb and is then used to construct two 3SvPSv metamorphic parallel mechanisms proposed in this paper. The phase change of the vA joints incurs the constraint change of the SvPSv limb and subsequently results in the change of mobility configuration of the metamorphic parallel mechanisms. The paper further addresses the geometrical condition for constructing 3SvPSv metamorphic parallel mechanisms following the constraints delivered by the reconfigurable limbs, leading to the analysis of mobility change of the mechanisms induced by the phase change of the limbs.


2018 ◽  
Vol 10 (3) ◽  
Author(s):  
Xinsheng Zhang ◽  
Pablo López-Custodio ◽  
Jian S. Dai

The kinematic chains that generate the planar motion group in which the prismatic-joint direction is always perpendicular to the revolute-joint axis have shown their effectiveness in type synthesis and mechanism analysis in parallel mechanisms. This paper extends the standard prismatic–revolute–prismatic (PRP) kinematic chain generating the planar motion group to a relatively generic case, in which one of the prismatic joint-directions is not necessarily perpendicular to the revolute-joint axis, leading to the discovery of a pseudo-helical motion with a variable pitch in a kinematic chain. The displacement of such a PRP chain generates a submanifold of the Schoenflies motion subgroup. This paper investigates for the first time this type of motion that is the variable-pitched pseudo-planar motion described by the above submanifold. Following the extraction of a helical motion from this skewed PRP kinematic chain, this paper investigates the bifurcated motion in a 3-prismatic–universal–prismatic (PUP) parallel mechanism by changing the active geometrical constraint in its configuration space. The method used in this contribution simplifies the analysis of such a parallel mechanism without resorting to an in-depth geometrical analysis and screw theory. Further, a parallel platform which can generate this skewed PRP type of motion is presented. An experimental test setup is based on a three-dimensional (3D) printed prototype of the 3-PUP parallel mechanism to detect the variable-pitched translation of the helical motion.


2004 ◽  
Vol 126 (1) ◽  
pp. 79-82 ◽  
Author(s):  
Q. C. Li ◽  
Z. Huang

Mobility analysis of a novel 3-5R parallel mechanism family whose limb consists of a 2R and a 3R parallel subchain is performed by the aid of screw theory. A mobility criterion applicable to such 3-leg parallel mechanisms in which each kinematic chain contains five kinematic pairs is proposed. It is shown that under different structural conditions, the 3-5R parallel mechanism can have 3, 4, or 5 DOF (degrees of freedom). The structural conditions that guarantee the full-cycle mobility are analyzed. The analysis and the method presented in this paper will be helpful in using such a 3-5R parallel mechanism family and introduce new insights into the mobility analysis of parallel mechanisms.


2013 ◽  
Vol 135 (10) ◽  
Author(s):  
Mats Isaksson ◽  
Matthew Watson

Parallel manipulators possess several advantages compared to serial robots, including the possibilities for high acceleration and high accuracy positioning of the manipulated platform. However, the majority of all proposed parallel mechanisms suffer from the combined drawbacks of a small positional workspace in relation to the manipulator footprint and a limited range of rotations of the manipulated platform. This paper analyses a recently proposed six-degrees-of-freedom parallel mechanism that aims to address both these issues while maintaining the traditional advantages of a parallel mechanism. The investigated manipulator consists of six actuated coaxial upper arms that are allowed to rotate indefinitely around a central cylindrical base column and a manipulated platform where five of the six joint positions are collinear. The axis-symmetric arm system leads to an extensive positional workspace while the proposed link arrangement increases the range of achievable platform rotations. The manipulator workspace is analyzed in detail and two methods to further increase the rotational workspace are presented. It is shown that the proposed manipulator has the possibility of a nonsingular transition of assembly modes, which extends the usable workspace. Furthermore, it is demonstrated how an additional kinematic chain can be utilized to achieve infinite platform rotation around one platform axis. By introducing additional mobility in the manipulated platform, a redundantly actuated mechanism is avoided.


2010 ◽  
Vol 33 ◽  
pp. 513-517
Author(s):  
Xiu Qin Huang ◽  
Hui Ping Shen ◽  
Xiu Mei Xin

The two novel 1-translation and 2-rotation parallel mechanisms are investigated. An analytic solutions corresponding to the forward and inverse position are obtained. The influences by the three input variables on the three output variables are analyzed carefully and the valid working ranges of input and output variables are given. The pros and cons are addressed by comparing with the two parallel mechanisms, and the optimal one of the two mechanisms is produced.The work of the paper provided a solid foundation for mechanical structural design and real-time controlling of the novel parallel mechanism.


2011 ◽  
Vol 320 ◽  
pp. 228-231 ◽  
Author(s):  
Xiu Qin Huang ◽  
Hui Ping Shen ◽  
Xiu Mei Xin

A novel 3 degree of freedom(1-Translation and 2-Rotation) parallel mechanisms is investigated. The forward and inverse position of the mechanism are studied. The influences by the three input variables on the three output variables are analyzed carefully and the valid working ranges of input and output variables are given by discussing structural parameter. These provide a solid foundation for selecting structural designs and kinematics parameters accurately and for realizing the control and industrial application of the mechanism.


Author(s):  
Huiping Shen ◽  
Yinan Zhao ◽  
Guanglei Wu ◽  
Ju Li ◽  
Damien Chablat

This paper presents the kinematic design of a translational parallel mechanism (PM) named Vari-Orthoglide by means of the workspace superposition, according to the sub-kinematic chain (SKC) based PM composition principle. The main topological characteristics of the manipulator with two SKCs under study, such as the position and orientation (POC) characteristics, degree of freedom (DOF) and coupling degree are analyzed, which turns out that the coupling degree equals to 1, implying the partially decoupled motion. With the topological characteristics based kinematic modeling principle, a symbolic model of the kinematics is established to derive its symbolic direct and inverse kinematic solutions. Based upon the direct kinematic solution, the workspaces for the two SKCs can be efficiently found. Moreover, the singularity loci are identified for finding the singularity-free workspace, where a regular workspace is fitted as the task workspace as expected. The presented work shows an approach to design translational parallel mechanisms considering motion decoupling and regular workspace, applicable to other types of parallel mechanisms.


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