Type synthesis of spatial mechanisms on the basis of spatial single loop structural groups

To discover single-degree-of-freedom (DOF) single-loop overconstrained mechanisms is still an open problem. This paper deals with the type synthesis of single DOF single-loop overconstrained 6RMCTs (6R spatial mechanisms for circular translation). These mechanisms provide alternatives to planar parallelograms and are also associated with self-motion of several translational parallel mechanisms. 6RMCTs are to be obtained using a construction approach in combination with the approaches to the type synthesis of parallel mechanisms. By imposing certain conditions on the hybrid overconstrained 6R (plano-spherical, plano-Bennett, double-spherical, and spherico-Bennett) mechanisms, Bricard plane symmetric mechanism, and Bricard line symmetric mechanism, six special cases of 6RMCTs are obtained. By combining planar parallelograms with these special mechanisms, the general cases of 6RMCTs are then constructed. Finally, 4R2H, 2R4H, and 6H mechanisms for circular translation are obtained from the above 6RMCTs by replacing one or more pairs of R (revolute) joints with parallel axes each with a pair of H (helical) joints with parallel axes and the same pitch. This work contributes to the research on overconstrained six-bar mechanisms and further reveals that the research areas of parallel mechanisms and single-loop overconstrained mechanisms are closely related.

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A Method for Type Synthesis of Mechanisms Using Phase Diagrams

23rd Biennial Mechanisms Conference: Mechanism Synthesis and Analysis ◽

10.1115/detc1994-0177 ◽

1994 ◽

Author(s):

Sio-Hou Lei ◽

Ying-Chien Tsai

Keyword(s):

Phase Diagram ◽

Degrees Of Freedom ◽

Practical Application ◽

Type Synthesis ◽

Planar Mechanisms ◽

Simple Loop ◽

Single Degree Of Freedom ◽

Single Degree ◽

Spatial Mechanisms ◽

Synthesis Of Mechanisms

Abstract A method for synthesizing the types of spatial as well as planar mechanisms is expressed in this paper by using the concept of phase diagram in metallurgy. The concept represented as a type synthesis technique is applied to (a) planar mechanisms with n degrees of freedom and simple loop, (b) spatial mechanisms with single degree of freedom and simple loop, to enumerate all the possible mechanisms with physically realizable kinematic pairs. Based on the technique described, a set of new reciprocating mechanisms is generated as a practical application.

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Type synthesis of 2R2T parallel mechanisms based on motion equivalent chain method

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/0954406214527271 ◽

2014 ◽

Vol 228 (17) ◽

pp. 3209-3217 ◽

Cited By ~ 8

Author(s):

Wei Ye ◽

Yuefa Fang ◽

Sheng Guo ◽

Haibo Qu

Keyword(s):

Parallel Mechanism ◽

Screw Theory ◽

Parallel Mechanisms ◽

Motion Pattern ◽

Type Synthesis ◽

Constraint Force ◽

Single Loop ◽

Loop Chain ◽

Serial Chains

In this paper, the motion equivalent chain method is proposed and then applied to the type synthesis of a class of 2R2T parallel mechanism. The equivalent serial chains are synthesized for a specific 2R2T motion pattern based on screw theory. Feasible limb structures that provide a constraint couple and a constraint force are enumerated according to the reciprocity of the twist and wrench systems. Several motion equivalent single loop chains are constructed with the equivalent serial chains. Using motion equivalent single loop chains to replace the equivalent serial chains, a class of 2R2T parallel mechanisms is obtained based on the foundation of motion equivalent single loop chain structures.

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A Transmissibility for Single-Loop Spatial Mechanisms

Transactions of the Japan Society of Mechanical Engineers ◽

10.1299/kikai1938.44.2497 ◽

1978 ◽

Vol 44 (383) ◽

pp. 2497-2504

Author(s):

Hiroshi SHIMOJIMA ◽

Kiyoshi OGAWA ◽

Toru KAWANO

Keyword(s):

Single Loop ◽

Spatial Mechanisms

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Assembly Configurations of Spatial Single-Loop Mechanisms With Revolute, Cylindric, and Prismatic Joints

Volume 1B: 25th Biennial Mechanisms Conference ◽

10.1115/detc98/mech-5897 ◽

1998 ◽

Author(s):

David E. Foster ◽

Raymond J. Cipra

Keyword(s):

Single Loop ◽

Spatial Mechanisms ◽

Prismatic Joints ◽

Spherical Mechanism

Abstract This paper examines the problem of identifying the assembly configurations (ACs), also called circuits, of certain spatial single-loop mechanisms. First, the spherical mechanism is considered; it is believed that such a mechanism has one AC if every pair of adjacent links can line up; otherwise, it has 2 ACs. Next, general spatial mechanisms with revolute, cylindric, and prismatic points are considered. If the mechanism has three or more sliding (cylindric or prismatic) joints, it is possible to find an equivalent spherical mechanism which has the same angular motions. However, it is also possible that at certain positions, some of the links may have to slide an infinite distance, which is not possible. Therefore, the mechanism may have more ACs than the equivalent spherical mechanism. Several examples are given, and some general conclusions are drawn.

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Type synthesis of single-loop deployable mechanisms based on improved atlas method for single-DOF grasping manipulators

Mechanism and Machine Theory ◽

10.1016/j.mechmachtheory.2021.104656 ◽

2022 ◽

Vol 169 ◽

pp. 104656

Author(s):

Yang Zhang ◽

Hailin Huang ◽

Tao Mei ◽

Bing Li

Keyword(s):

Type Synthesis ◽

Single Loop ◽

Atlas Method

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Type Synthesis of Spatial Mechanisms with Consideration of General Constraint.

TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series C ◽

10.1299/kikaic.62.1182 ◽

1996 ◽

Vol 62 (595) ◽

pp. 1182-1190

Author(s):

Yoshihiro SAKAMOTO ◽

Kiyoshi OGAWA ◽

Yoshihiko HAGIWARA ◽

Mikio HORIE ◽

Takayuki ARISHIMA

Keyword(s):

Type Synthesis ◽

General Constraint ◽

Spatial Mechanisms

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Closed Form Displacement Relationships of Single and Multi-Loop Six-Link Spatial Mechanisms

Journal of Engineering for Industry ◽

10.1115/1.3438214 ◽

1973 ◽

Vol 95 (3) ◽

pp. 709-716 ◽

Cited By ~ 2

Author(s):

A. H. Soni ◽

R. V. Dukkipati ◽

M. Huang

Keyword(s):

Closed Form ◽

Single Loop ◽

Spatial Mechanisms

Using (3 × 3) matrices with dual elements, two loop Watt and Stephenson type six-link spatial mechanisms with one revolute and six cylinder pairs and single loop R-C-R-R-P-R, R-C-R-R-R-R six-link mechanisms are examined to obtain closed form displacement relationships between independent and dependent displacement parameters. Displacement analyses are performed to illustrate the use of these displacement relationships.

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