scholarly journals Design and DOF Analysis of a Novel Compliant Parallel Mechanism for Large Load

Sensors ◽  
2019 ◽  
Vol 19 (4) ◽  
pp. 828 ◽  
Author(s):  
Xiaochuan Wu ◽  
Yi Lu ◽  
Xuechao Duan ◽  
Dan Zhang ◽  
Wenyao Deng
Keyword(s):  
Finite Element ◽  
Parallel Mechanism ◽  
Screw Theory ◽  
Load Capacity ◽  
Spherical Joint ◽  
Analysis Model ◽  
Compliance Matrix ◽  
Large Load ◽  
Compliant Parallel Mechanism ◽  
Six Dof

The degree of freedom (DOF) and motion characteristics of a kind of compliant spherical joint were analyzed based on the screw theory, and a new design scheme for force-inversion of the compliant spherical joint was proposed in this paper. A novel type of six DOF compliant parallel mechanism (CPM) was designed based on this scheme to provide a large load capacity and achieve micrometer-level positioning accuracy. The compliance matrix of the new type of CPM was obtained through matrix transformation and was then decomposed into its generalized eigenvalues. Then, the DOF of the mechanism was numerically analyzed based on the symbolic formulation. The finite element analysis model of the compliant parallel mechanism was established. The static load analysis was used to verify the large load capacity of the mobile platform. By comparing the deformation obtained by the compliance matrix numerical method with the deformation obtained by the finite element method, the correctness of the compliance matrix and the number of the DOF of the CPM was verified.

A Quasi-Static Model for Planar Compliant Parallel Mechanisms

2009 ◽  
Vol 1 (2) ◽  
Author(s):  
Cyril Quennouelle ◽  
Clément Gosselin
Keyword(s):  
Parallel Mechanism ◽  
Applied Load ◽  
Jacobian Matrix ◽  
Static Model ◽  
Parallel Mechanisms ◽  
Compliance Matrix ◽  
End Effector ◽  
Kinematic Constraints ◽  
Compliant Parallel Mechanism ◽  
External Loads

In this paper, the mobility, the kinematic constraints, the pose of the end-effector, and the static constraints that lead to the kinematostatic model of a compliant parallel mechanism are introduced. A formulation is then provided for its instantaneous variation—the quasi-static model. This new model allows the calculation of the variation in the pose as a linear function of the motion of the actuators and the variation in the external loads through two new matrices: the compliant Jacobian matrix and the Cartesian compliance matrix that give a simple and meaningful formulation of the model of the mechanism. Finally, a simple application to a planar four-bar mechanism is presented to illustrate the use of this model and the new possibilities that it opens, notably the study of the kinematics for any range of applied load.

Six-Dimensional Compliance Analysis and Validation of Orthoplanar Springs

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Chen Qiu ◽  
Peng Qi ◽  
Hongbin Liu ◽  
Kaspar Althoefer ◽  
Jian S. Dai
Keyword(s):  
Finite Element ◽  
Parallel Mechanism ◽  
Fem Simulation ◽  
Analytical Models ◽  
Compliance Matrix ◽  
Out Of Plane ◽  
Continuum Manipulator ◽  
First Time ◽  
Good Agreement

This paper for the first time investigates the six-dimensional compliance characteristics of orthoplanar springs using a compliance-matrix based approach, and validates them with both finite element (FEM) simulation and experiments. The compliance matrix is developed by treating an orthoplanar spring as a parallel mechanism and is revealed to be diagonal. As a consequence, corresponding diagonal compliance elements are evaluated and analyzed in forms of their ratios, revealing that an orthoplanar spring not only has a large linear out-of-plane compliance but also has a large rotational bending compliance. Both FEM simulation and experiments were then conducted to validate the developed compliance matrix. In the FEM simulation, a total number of 30 types of planar-spring models were examined, followed by experiments that examined the typical side-type and radial-type planar springs, presenting a good agreement between the experiment results and analytical models. Further a planar-spring based continuum manipulator was developed to demonstrate the large-bending capability of its planar-spring modules.

The design and kinetostatic modeling of 3PPR planar compliant parallel mechanism based on compliance matrix method

2019 ◽  
Vol 90 (4) ◽  
pp. 045102 ◽  
Author(s):  
Hongtao Yu ◽  
Chi Zhang ◽  
Bao Yang ◽  
Si-Lu Chen ◽  
Zaojun Fang ◽  
...  
Keyword(s):  
Matrix Method ◽  
Parallel Mechanism ◽  
Compliance Matrix ◽  
Compliant Parallel Mechanism ◽  
Compliance Matrix Method

Compliant Mechanism Reconfiguration Based on Position Space Concept for Reducing Parasitic Motion

2015 ◽  
Author(s):  
Haiyang Li ◽  
Guangbo Hao
Keyword(s):  
Finite Element Analysis ◽  
Parallel Mechanism ◽  
Screw Theory ◽  
Compliant Mechanism ◽  
Position Space ◽  
Element Analysis ◽  
Compact Structure ◽  
Parasitic Motion ◽  
Compliant Parallel Mechanism ◽  
Space Concept

This paper introduces a compliant mechanism reconfiguration approach that can be used to minimize the parasitic motions of a compliant mechanism. This reconfiguration approach is based on the position spaces, identified by the screw theory, of independent compliant modules in a compliant mechanism system. The parasitic motions (rotations) of a compliant mechanism are first modelled associated with the variables representing any positions of the compliant modules in the position spaces. The optimal positions of the compliant modules are then obtained where the parasitic motions are reduced to minimal values. A procedure of the compliant mechanism reconfiguration approach is summarized and demonstrated using a decoupled XYZ compliant parallel mechanism as an example. The analytical results show that the parasitic motions of the XYZ compliant parallel mechanism in the example can be dramatically reduced by the position/structure reconfiguration, which is also validated by finite element analysis. The position space of a compliant module contains a number of possible positions, thus a compliant mechanism can also be efficiently reconfigured to a variety of practical patterns such as the configuration with compact structure.

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.

Constraint-Based Design and Analysis of a Compliant Parallel Mechanism Using SMA-Spring Actuators

2014 ◽  
Author(s):  
C. Qiu ◽  
K. Zhang ◽  
Jian S. Dai
Keyword(s):  
Parallel Mechanism ◽  
Screw Theory ◽  
Parallel Mechanisms ◽  
Element Simulation ◽  
Compliant Parallel Mechanism ◽  
Physical Prototype ◽  
Simulation And Experiment ◽  
Parallel Platform ◽  
Sma Spring ◽  
Actuation Systems

This paper presents a novel compliant parallel mechanism that utilizes shape-memory-alloy (SMA) spring based actuators. By employing SMA coil springs, the traditional line constraint that resists translation along its axis but no other forms of motions is transformed into a linear actuator that can generate deflection along its axis, which leads to the design of SMA-spring linear actuators. In accordance with this SMA actuator, an constraint-based approach in the framework of screw theory is utilized to synthesize the constraint and actuation space of parallel mechanisms, and a novel 4 DOF parallel platform is developed based on this analytical approach. A physical prototype is manufactured by employing the SMA-spring actuators, and its mobility and workspace are verified with both finite element simulation and experiment observations. The results illustrate this parallel mechanism has a large workspace in all desired mobility configurations. The presented work on the parallel platform demonstrates the efficiency of the constraint-based approach in determining the layout of actuation systems, also the developed SMA actuators pave a new way for applying the SMA technique in the future development of compliant parallel mechanisms and robotics.

scholarly journals A novel 5-DOF high-precision compliant parallel mechanism for large-aperture grating tiling

2017 ◽  
Vol 8 (2) ◽  
pp. 349-358 ◽  
Author(s):  
Zhongxi Shao ◽  
Shilei Wu ◽  
Jinguo Wu ◽  
Hongya Fu
Keyword(s):  
High Precision ◽  
Parallel Mechanism ◽  
Closed Loop ◽  
Load Capacity ◽  
Performance Testing ◽  
Closed Loop Control ◽  
Parallel Mechanisms ◽  
Loop Control ◽  
Large Aperture ◽  
Compliant Parallel Mechanism

Abstract. In combination with the advantages of parallel mechanisms and compliant mechanisms, a 5-DOF compliant parallel mechanism is designed to meet the requirements, such as large stroke, large load capacity, high precision and high stability, for a large-aperture grating tiling device. The structure and characteristics of the 5-DOF compliant parallel mechanism are presented. The kinematics of the mechanism are derived based on a pseudo-rigid-body model as well. To increase the tiling position retention stability of the mechanism, a closed-loop control system with capacitive position sensors, which are employed to provide feedback signals, is realized. A position and orientation monitoring algorithm and a single neuron adaptive full closed-loop control algorithm are proposed. Performance testing is implemented to verify the accuracy and the tiling position retention stability of the grating tiling device. The experimental results indicate that the tiling accuracy reaches 0.2 µrad per step and 20 nm per step, and the tiling position retention stability can achieve 1.2 µrad per 30 min and 35 nm per 30 min in the rotational direction and the translational direction, respectively.

Six-DOF micro-manipulator based on compliant parallel mechanism with integrated force sensor

2011 ◽  
Vol 27 (1) ◽  
pp. 124-134 ◽  
Author(s):  
Qiaokang Liang ◽  
Dan Zhang ◽  
Zhongzhe Chi ◽  
Quanjun Song ◽  
Yunjian Ge ◽  
...  
Keyword(s):  
Parallel Mechanism ◽  
Force Sensor ◽  
Compliant Parallel Mechanism ◽  
Micro Manipulator ◽  
Six Dof

scholarly journals A Decoupled 6-DOF Compliant Parallel Mechanism with Optimized Dynamic Characteristics Using Cellular Structure

Machines ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 5
Author(s):  
Minh Tuan Pham ◽  
Song Huat Yeo ◽  
Tat Joo Teo ◽  
Pan Wang ◽  
Mui Ling Sharon Nai
Keyword(s):  
Parallel Mechanism ◽  
Cellular Structure ◽  
Degrees Of Freedom ◽  
Dynamic Properties ◽  
Dynamic Performance ◽  
Three Dimensional ◽  
Optimization Method ◽  
End Effector ◽  
Compliant Parallel Mechanism ◽  
Six Dof

This paper presents a novel six degrees-of-freedom (DOF) compliant parallel mechanism (CPM) with decoupled output motions, large workspace of ≥6 mm for translations and ≥12° for rotations, optimized stiffness, and dynamic properties. The working range and the motion decoupling capability of the six-DOF CPM are experimentally verified, and the mechanical properties are shown to be predictable. The proposed CPM is synthesized by applying the beam-based structural optimization method together with the criteria for achieving motion decoupling capability. In order to improve the dynamic behaviors for the CPM, cellular structure is used to design its end effector. The obtained results show that the dynamic performance of the CPM with cellular end effector is significantly enhanced with the increase of 33% of the first resonance frequency as compared to the initial design. Performances of the three-dimensional (3D)-printed prototype are experimentally evaluated in terms of mechanical characteristics and decoupled motions. The obtained results show that the actual stiffness and dynamic properties agree with the predictions with the highest deviation of ~10.5%. The motion decoupling capability of the CPM is also demonstrated since almost input energy (>99.5%) generates the desired output motions while the energy causes parasitic motions is only minor (<0.5%).

Load Testing to Collapse Limit State of Barr Creek Bridge

2000 ◽  
Vol 1696 (1) ◽  
pp. 92-102 ◽  
Author(s):  
Nicholas Haritos ◽  
Anil Hira ◽  
Priyan Mendis ◽  
Rob Heywood ◽  
Armando Giufre
Keyword(s):  
Finite Element ◽  
Failure Modes ◽  
Flexural Rigidity ◽  
Load Capacity ◽  
Limit State ◽  
Dynamic Test ◽  
Service Condition ◽  
Flat Slab ◽  
Testing Program ◽  
Static Testing

VicRoads, the road authority for the state of Victoria, Australia, has been undertaking extensive research into the load capacity and performance of cast-in-place reinforced concrete flat slab bridges. One of the key objectives of this research is the development of analytical tools that can be used to better determine the performance of these bridges under loadings to the elastic limit and subsequently to failure. The 59-year-old Barr Creek Bridge, a flat slab bridge of four short continuous spans over column piers, was made available to VicRoads in aid of this research. The static testing program executed on this bridge was therefore aimed at providing a comprehensive set of measurements of its response to serviceability level loadings and beyond. This test program was preceded by the performance of a dynamic test (a simplified experimental modal analysis using vehicular excitation) to establish basic structural properties of the bridge (effective flexural rigidity, EI) and the influence of the abutment supports from identification of its dynamic modal characteristics. The dynamic test results enabled a reliably tuned finite element model of the bridge in its in-service condition to be produced for use in conjunction with the static testing program. The results of the static testing program compared well with finite element modeling predictions in both the elastic range (serviceability loadings) and the nonlinear range (load levels taken to incipient collapse). Observed collapse failure modes and corresponding collapse load levels were also found to be predicted well using yield line theory.

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