Type synthesis of 1T2R parallel mechanisms with parasitic motions

Sun, Tao; Huo, Xinming

doi:10.1016/j.mechmachtheory.2018.05.014

Cited by 62 publications

(20 citation statements)

References 31 publications

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“…Whereas for a PM, the finite screw of its moving platform can be obtained as the intersection of finite screws of all the limbs. Under the guidance of these principles, a synthesis method based on the finite screw has been proposed and applied to the type synthesis of 3T PMs [56], 3T1R PMs with a variable rotational axis [57], 2T3R PMs [58], and 1T2R PMs [59]. This method mainly has two features.…”

Section: Finite Screw Methodsmentioning

confidence: 99%

“…The investigation on systematic type synthesis approaches of lower mobility PMs dates back to the last century and has experienced a gold period with great progress at the beginning of this century. Based on various mathematical tools, a variety of approaches have been presented in the literature, including the Lie group theory-based method [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29], the method based on G F (generalized function) sets [30][31][32][33][34][35], linear transformation method [36][37][38][39][40][41][42][43][44][45][46], position and orientation characteristic (POC) set method [47][48][49][50][51][52], finite screw method [53][54][55][56][57][58][59], screw theory-based method …”

Section: Introductionmentioning

confidence: 99%

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Type Synthesis of Lower Mobility Parallel Mechanisms: A Review

2019

Chin. J. Mech. Eng.

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Type synthesis of mechanisms aims to systematically determine all possible structures for a specific mobility requirement. Numerous methods based on different theories were proposed for type synthesis of lower mobility parallel mechanisms in past decades. However, there does not exist a comprehensive review on these approaches. Therefore, the goal of this paper is to give such a review, classifying the approaches proposed in the literature into three groups, namely, motion-based methods, constraint-based methods, and other methods. The motion-based methods include the Lie group based method, the G F set method, the linear transformation method, the POC set method, and the finite screw method. The constraint-based methods involve the screw theory-based method, the virtual chain method, the method based on Grassmann line geometry and line graphs, and the motion constraint generator method. Other methods contain the enumeration approach based on the general CGK mobility formula and the graph theory method. Upon thoroughly analyzing the characteristics and/or limitations of each method, this review provides a well reference to help researchers find an effective synthesis method for innovative design and further scientific investigations for mechanisms.

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Section: Finite Screw Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Type Synthesis of Lower Mobility Parallel Mechanisms: A Review

2019

Chin. J. Mech. Eng.

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“…Among them, redundant actuated parallel mechanisms with symmetry are less. For 2R1T and 2T1R three-DOF parallel mechanisms, most scholars [24][25][26][27][28][29][30] are only aimed at the type synthesis of non-redundant drive parallel mechanisms.…”

Section: Introductionmentioning

confidence: 99%

A New Method for Type Synthesis of 2R1T and 2T1R 3-DOF Redundant Actuated Parallel Mechanisms with Closed Loop Units

Zhang

2020

Chin. J. Mech. Eng.

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The current type synthesis of the redundant actuated parallel mechanisms is adding active-actuated kinematic branches on the basis of the traditional parallel mechanisms, or using screw theory to perform multiple getting intersection and union to complete type synthesis. The number of redundant parallel mechanisms obtained by these two methods is limited. In this paper, based on Grassmann line geometry and Atlas method, a novel and effective method for type synthesis of redundant actuated parallel mechanisms (PMs) with closed-loop units is proposed. Firstly, the degree of freedom (DOF) and constraint line graph of the moving platform are determined successively, and redundant lines are added in constraint line graph to obtain the redundant constraint line graph and their equivalent line graph, and a branch constraint allocation scheme is formulated based on the allocation criteria. Secondly, a scheme is selected and redundant lines are added in the branch chains DOF graph to construct the redundant actuated branch chains with closed-loop units. Finally, the branch chains that meet the requirements of branch chains configuration criteria and F&C (degree of freedom & constraint) line graph are assembled. In this paper, two types of 2 rotational and 1 translational (2R1T) redundant actuated parallel mechanisms and one type of 2 translational and 1 rotational (2T1R) redundant actuated parallel mechanisms with few branches and closed-loop units were taken as examples, and 238, 92 and 15 new configurations were synthesized. All the mechanisms contain closed-loop units, and the mechanisms and the actuators both have good symmetry. Therefore, all the mechanisms have excellent comprehensive performance, in which the two rotational DOFs of the moving platform of 2R1T redundant actuated parallel mechanism can be independently controlled. The instantaneous analysis shows that all mechanisms are not instantaneous, which proves the feasibility and practicability of the method.

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“…The famous Z3 spindle head [17] and A3 spindle head [18] are classic architectures which are built by the 3-PRS (R: Revolute joint; P: Prismatic joint; S: Spherical joint) and 3-RPS parallel structures respectively and both output 2R1T motion type. Numerous 2R1T PMs with or without parasitic motions have also been proposed [19][20][21]. Besides, the control method and strategy of 3RPS have also been studied [22].…”

Section: Introductionmentioning

confidence: 99%

Design and analysis of a class of redundant collaborative manipulators with 2D large rotational angles

et al. 2019

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The parallel spindle heads with high rotational capability are demanded in the area of multi-axis machine tools and 3D printers. This paper focuses on designing a class of 2R1T (R: Rotation; T: Translation) parallel spindle heads and the corresponding collaborative 5-axis manipulators with 2-dimension (2D) large rotational angles. In order to construct 2D rotational degrees of freedom (DOFs), a platform with 2D revolute joints is proposed first. Based on the constraint screw theory, the feasible limbs that can be connected in the platform are synthesized. In order to provide constant rotational axis for the platform, a class of redundant limbs are designed. A class of redundant 2R1T parallel spindle heads is obtained by connecting the redundant limbs with the platform and the redundant characteristics are verified by the modified Grübler-Kutzbach criterion. The corresponding 5-axis collaborative manipulators are presented by constructing a 2-DOF series translational bottom moving platform. The inverse kinematics and the orientation workspace as well as the decoupling characteristics of this type of 2R1T parallel spindle heads are analyzed. The results show that these manipulators have large 2D rotational angles than the traditional A3/Z3 heads and can be potentially used in the application of multi-axis machine tools and the 3D printers.

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Type synthesis of 1T2R parallel mechanisms with parasitic motions

Cited by 62 publications

References 31 publications

Type Synthesis of Lower Mobility Parallel Mechanisms: A Review

Type Synthesis of Lower Mobility Parallel Mechanisms: A Review

A New Method for Type Synthesis of 2R1T and 2T1R 3-DOF Redundant Actuated Parallel Mechanisms with Closed Loop Units

Design and analysis of a class of redundant collaborative manipulators with 2D large rotational angles

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