Flexure Parallel Mechanism: Configuration and Performance Improvement of a Compact Acceleration Sensor

2012 ◽  
Vol 4 (3) ◽  
Author(s):  
Zhen Gao ◽  
Dan Zhang
Keyword(s):  
Parallel Mechanism ◽  
Structure Evolution ◽  
Cantilever Beams ◽  
Parallel Mechanisms ◽  
Acceleration Sensor ◽  
Element Analysis ◽  
Revolute Joints ◽  
Kinematics Modeling ◽  
And Performance ◽  
Monolithic Structure

This research presents a tridimensional acceleration sensor based on flexure parallel mechanism (FPM). Three perpendicular compliant limbs with compact monolithic structure are developed to serve as the elastic component for acquiring the inertial signals in each direction. With integrated flexure hinges, each chain containing multiple revolute joints and cantilever beams are designed to carry compressive and tensile loads. First, the structure evolution and kinematics modeling are introduced, followed by the multispring modeling of the directional compliance for the flexure limb. Then, the comprehensive finite-element analysis (FEA) including the strain of the sensitive limbs, modal analysis for total deformation under different frequency is conducted. The compliances calculated by FEA and multispring model are compared. Finally, the dimensional optimization is implemented based on multipopulation genetic algorithm to obtain the optimal flexure parameters. The proposed methods and algorithms are also useful for the analysis and development of other flexure parallel mechanisms.

Conceptual Design, Performance Evaluation and Dimensional Optimization of a Compact Acceleration Sensor Based on Flexure Parallel Mechanisms

2011 ◽  
Author(s):  
Dan Zhang ◽  
Zhen Gao
Keyword(s):  
Structure Evolution ◽  
Cantilever Beams ◽  
Parallel Mechanisms ◽  
Acceleration Sensor ◽  
Element Analysis ◽  
Revolute Joints ◽  
Kinematics Modeling ◽  
Population Genetic Algorithm ◽  
Monolithic Structure ◽  
Dimensional Optimization

In this paper, a tridimensional acceleration sensor based on flexure parallel mechanism (FPM) is presented. Three perpendicular compliant legs with compact monolithic structure are served as the elastic body for sensing the inertial signals in each direction. With integrated flexure hinges, each chain containing multiple revolute joints and cantilever beams are designed to carry compressive and tensile loads. Firstly, the structure evolution and kinematics modeling are introduced, followed by the multi-spring modeling of the directional compliance for the flexure leg. Then, the comprehensive finite-element analysis (FEA) including the strain of the sensitive legs, modal analysis for total deformation under different frequency is conducted. The compliances calculated by FEA and multi-spring model are compared. Finally, the dimensional optimization is implemented based on multi-population genetic algorithm to obtain the optimal flexure parameters. The proposed methods and algorithms are also useful for the analysis and development of other flexure parallel mechanisms.

scholarly journals The Effect of the Optimization Selection of Position Analysis Route on the Forward Position Solutions of Parallel Mechanisms

Robotics ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 93
Author(s):  
Huiping Shen ◽  
Qing Xu ◽  
Ju Li ◽  
Ting-li Yang
Keyword(s):  
Parallel Mechanism ◽  
Selection Criterion ◽  
Parallel Mechanisms ◽  
Position Analysis ◽  
Kinematics Modeling ◽  
Position Solution ◽  
Independent Loops ◽  
Selection Of

The forward position solution (FPS) of any complex parallel mechanism (PM) can be solved through solving in sequence all of the independent loops contained in the PM. Therefore, when solving the positions of a PM, all independent loops, especially the first loop, must be correctly selected. The optimization selection criterion of the position analysis route (PAR) proposed for the FPS is presented in this paper, which can not only make kinematics modeling and solving efficient but also make it easy to get its symbolic position solutions. Two three-translation PMs are used as the examples to illustrate the optimization selection of their PARs and obtain their symbolic position solutions.

scholarly journals Type synthesis and kinematics analysis of a family of three translational and one rotational pick-and-place parallel mechanisms with high rotational capability

2019 ◽  
Vol 11 (6) ◽  
pp. 168781401985307
Author(s):  
Xing Zhang ◽  
Dejun Mu ◽  
Yuze Liu ◽  
Jie Bi ◽  
Hongrui Wang
Keyword(s):  
Parallel Mechanism ◽  
Jacobian Matrix ◽  
Hessian Matrix ◽  
Parallel Mechanisms ◽  
Kinematics Analysis ◽  
Type Synthesis ◽  
Lie Group Theory ◽  
Revolute Joints ◽  
Pick And Place ◽  
Pick And Place Operation

This article proposes a family of spatial three translational and one rotational parallel mechanisms (PMs) for pick-and-place operation. Their features are one independent rotation of the mechanism with four identical limbs, which are provided by the four revolute joints on the moving platform. The rotational capability of the PMs has a range of at least 180°. This article focuses on the synthesis of the PMs and kinematics analysis of the 4- P(2-SS)R parallel mechanism. First, based on the Lie group theory, three parallelograms are used in designing the PMs. The limbs are listed and two types of three translational and one rotational PMs are synthesized. Then, a typical 4- P(2-SS)R PM is selected, the 6 × 6 Jacobian matrix and the 6 × 6 × 6 Hessian matrix of the mechanism are derived for solving the displacement, velocity, and acceleration of the mechanism. Finally, singularity configurations are disclosed from the 6 × 6 Jacobian matrix, and the workspace of the mechanism is provided to illustrate the high rotational capability.

Design of a 3-DOF Compliant Parallel Mechanism for Displacement Amplification

2013 ◽  
Author(s):  
Qiang Zeng ◽  
Kornel F. Ehmann
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Heat Balance ◽  
Parallel Mechanism ◽  
Compliant Mechanism ◽  
Element Analysis ◽  
Resonant Frequencies ◽  
Compact Size ◽  
Compliant Parallel Mechanism ◽  
Monolithic Structure

Prevalent general design methods and applications of compliant displacement amplifiers are focused on 1-DOF units composed into serial structures, which are limited by their output motions, stiffness, heat balance, repeatability and resonant frequencies. To improve the output properties of compliant displacement amplifiers, a monolithic structure is presented in the form of a compliant parallel mechanism. In the proposed moving structure, the compliant mechanism of the displacement amplifier is designed with 3-DOF to generate uniformly magnified output properties in all directions. High first resonant frequencies and amplification ratios are achieved in a compact size compared to existing compliant displacement amplifiers. The related kinematics, amplification ratios and resonant frequencies of the amplifier are analytically modeled, and the results are simulated by finite-element analysis. The proposed design is employable for micro/nano positioning stages operating within a prismatic output workspace.

scholarly journals Kinematic analysis of a novel 3-CRU translational parallel mechanism

2015 ◽  
Vol 6 (1) ◽  
pp. 57-64 ◽  
Author(s):  
B. Li ◽  
Y. M. Li ◽  
X. H. Zhao ◽  
W. M. Ge
Keyword(s):  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Jacobian Matrix ◽  
Screw Theory ◽  
Structural Characteristics ◽  
Parallel Mechanisms ◽  
Reachable Workspace ◽  
Potential Applications ◽  
Moving Platform ◽  
And Performance

Abstract. In this paper, a modified 3-DOF (degrees of freedom) translational parallel mechanism (TPM) three-CRU (C, R, and U represent the cylindrical, revolute, and universal joints, respectively) structure is proposed. The architecture of the TPM is comprised of a moving platform attached to a base through three CRU jointed serial linkages. The prismatic motions of the cylindrical joints are considered to be actively actuated. Kinematics and performance of the TPM are studied systematically. Firstly, the structural characteristics of the mechanism are described, and then some comparisons are made with the existing 3-CRU parallel mechanisms. Although these two 3-CRU parallel mechanisms are both composed of the same CRU limbs, the types of freedoms are completely different due to the different arrangements of limbs. The DOFs of this TPM are analyzed by means of screw theory. Secondly, both the inverse and forward displacements are derived in closed form, and then these two problems are calculated directly in explicit form. Thereafter, the Jacobian matrix of the mechanism is derived, the performances of the mechanism are evaluated based on the conditioning index, and the performance of a 3-CRU TPM changing with the actuator layout angle is investigated. Thirdly, the workspace of the mechanism is obtained based on the forward position analysis, and the reachable workspace volume is derived when the actuator layout angle is changed. Finally, some conclusions are given and the potential applications of the mechanism are pointed out.

scholarly journals Statics Analyses of a Riveting Robot based on 6-SPU Parallel Mechanism

2018 ◽  
Vol 232 ◽  
pp. 03048
Author(s):  
Zheng Liang ◽  
Yong Xu ◽  
Yeping Lv ◽  
Yong Xu
Keyword(s):  
Automotive Industry ◽  
Parallel Mechanism ◽  
High Efficiency ◽  
Structure Optimization ◽  
Aviation Industry ◽  
Analysis Software ◽  
Element Analysis ◽  
Thin Walled ◽  
And Performance ◽  
Optimization And Performance

A new walking riveting robot based on 6-SPU parallel mechanism is designed to meet the needs of high precision and high efficiency machining for large, thin-walled and complex curved surface workpieces in aviation industry and automotive industry. After modeling and solving the position inverse solution of the robot, the riveting trajectory planning is carried out, and the correct positions and orientations of riveting holes are determined. For the workpiece with large thin-walled cylindrical surface, the riveting hole process of the robot is simulated by finite element analysis software, the maximum deformations in all orientations and the maximum equivalent stresses of the moving platform corresponding to riveting points are obtained. The above results provide the necessary theoretical basis for the structure optimization and performance analyses of the automatic riveting robot.

scholarly journals Performance Evaluation of a Sensor Concept for Solving the Direct Kinematics Problem of General Planar 3-RPR Parallel Mechanisms by Using Solely the Linear Actuators’ Orientations

Robotics ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 72 ◽  
Author(s):  
Stefan Schulz
Keyword(s):  
Lower Bound ◽  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Parallel Robot ◽  
Parallel Mechanisms ◽  
Revolute Joints ◽  
Prismatic Joints ◽  
Measurement Units ◽  
Linear Actuators ◽  
Direct Kinematics

In this paper, we experimentally evaluate the performance of a sensor concept for solving the direct kinematics problem of a general planar 3-RPR parallel mechanism by using solely the linear actuators’ orientations. At first, we review classical methods for solving the direct kinematics problem of parallel mechanisms and discuss their disadvantages on the example of the general planar 3-RPR parallel mechanism, a planar parallel robot with two translational and one rotational degrees of freedom, where P denotes active prismatic joints and R denotes passive revolute joints. In order to avoid these disadvantages, we present a sensor concept together with an analytical formulation for solving the direct kinematics problem of a general planar 3-RPR parallel mechanism where the number of possible assembly modes can be significantly reduced when the linear actuators’ orientations are used instead of their lengths. By measuring the orientations of the linear actuators, provided, for example, by inertial measurement units, only two assembly modes exist. Finally, we investigate the accuracy of our direct kinematics solution under static as well as dynamic conditions by performing experiments on a specially designed prototype. We also investigate the solution formulation’s amplification of measurement noise on the calculated pose and show that the Cramér-Rao lower bound can be used to estimate the lower bound of the expected variances for a specific pose based exclusively on the variances of the linear actuators’ orientations.

scholarly journals Higher-Order Kinematics Modeling of 3-RRS Parallel Mechanism Based on CGA

2020 ◽  
Author(s):  
Chang Wang ◽  
Tieshi Zhao ◽  
Erwei Li ◽  
Yanzhi Zhao ◽  
Hui Bian ◽  
...  
Keyword(s):  
Clifford Algebra ◽  
Parallel Mechanism ◽  
Robot Vision ◽  
Higher Order ◽  
Rigid Bodies ◽  
Human Robot Interaction ◽  
Parallel Mechanisms ◽  
Kinematics Modeling ◽  
The Matrix ◽  
Mathematical Relationships

Abstract Higher-order kinematics of mechanisms has been applied in servo motor control, human-robot interaction and machinery life design fields, etc. The representations of acceleration and jerk by screws have been fully developed by researchers with the methods of the differential of the matrix representation of SE(3) group. Clifford algebra, which is tighter and with higher computational efficiency than the matrix method, is another representation of the motions of rigid bodies. It has been used in position kinematics, grub task motion planning, and robot vision for its convenience of geometric representations and calculations. As far as we know, the work of higher-order kinematics of mechanisms based on Clifford algebra is rare. First, after recalling the based theory of motion representation in conformal geometric algebra (CGA), the mathematical relationships between flag and motor are built. Second, a method for the higher-order kinematics modeling of serial chain mechanisms is proposed. Finally, the higher-order kinematics of the 3-RRS parallel mechanism is built to prove the correctness of the algorithm. This work further enriches the application of CGA for the higher-order kinematics modeling of parallel mechanisms.

Design, implementation, and performance evaluation of a 4-DOF parallel robot

Robotica ◽  
2009 ◽  
Vol 28 (1) ◽  
pp. 107-118 ◽  
Author(s):  
Hee-Byoung Choi ◽  
Atsushi Konno ◽  
Masaru Uchiyama
Keyword(s):  
Performance Evaluation ◽  
Parallel Mechanism ◽  
High Speed ◽  
Parallel Robot ◽  
Necessary Condition ◽  
Parallel Mechanisms ◽  
System Configuration ◽  
Tracking Accuracy ◽  
New Type ◽  
And Performance

SUMMARYThis paper deals with the design, implementation, and performance evaluation of a new type of 4-DOF parallel mechanism providing three translations and one rotation for high-speed handling and machining. This parallel mechanism is named H4. A necessary condition and system configuration of the H4 are also described. Hardware and kinematics of the H4 is addressed and the manipulability ellipsoid which is one of the widely used methods to examine the design of parallel mechanisms is addressed. The performance evaluation is carried out to demonstrate the H4 robot. The simulation and experimental results show that three different controllers, the PD, PD + velocity feed-forward, and dynamic compensation controller, dramatically improve the trajectory tracking accuracy.

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