Design, Modeling, and Analysis of a Novel Microgripper Based on Flexure Hinges

A new 2-DOF microgripper, which can perform the processing of the objects assembly and biological cells injection, is designed and modeled in this paper. The clamping action of the microgripper with the x direction is completed, however, when anything is clamped by the end effector, which can be completely driven by an actuator generated in y direction, at lastclamping and pushing motion are realized. The flexure hinge, which takes place of the conventional joint, is used as the translational and rotational hinges in the new structure. Otherwise, the whole microgripper is monolithic processing, which can efficiently overcome the disadvantages of the conventional hinge with friction, backlash, anderrors caused by the hinge assembly. Firstly, a kind of novel microgripper is designed in this paper, which can accomplish two-dimensional independent motions including a separate grip and single track push without interfering with each other. The bridge type amplifying structure with two-end output is adopted in the gripper to increase the motion range and the capacity of the microgripper. The piezoelectric actuator with fast response and high resolution is used as the drive element. Secondly, the geometrical and kinematical models are established and the formulas of the amplifying ratio, stiffness, maximum stress, and the natural frequency of this model are calculated, respectively. Finally, the FEM (finite element modeling) based on ANSYS software is built up to validate the formulas.

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Multi-objective optimization of a type of ellipse-parabola shaped superelastic flexure hinge

Mechanical Sciences ◽

10.5194/ms-7-127-2016 ◽

2016 ◽

Vol 7 (1) ◽

pp. 127-134 ◽

Cited By ~ 4

Author(s):

Zhijiang Du ◽

Miao Yang ◽

Wei Dong

Keyword(s):

Compliant Mechanisms ◽

Pareto Frontier ◽

Flexure Hinge ◽

Multi Objective Optimization ◽

Nsga Ii ◽

Element Analysis ◽

Multi Objective ◽

Flexure Hinges ◽

Static Responses ◽

Motion Range

Abstract. Flexure hinges made of superelastic materials is a promising candidate to enhance the movability of compliant mechanisms. In this paper, we focus on the multi-objective optimization of a type of ellipse-parabola shaped superelastic flexure hinge. The objective is to determine a set of optimal geometric parameters that maximizes the motion range and the relative compliance of the flexure hinge and minimizes the relative rotation error during the deformation as well. Firstly, the paper presents a new type of ellipse-parabola shaped flexure hinge which is constructed by an ellipse arc and a parabola curve. Then, the static responses of superelastic flexure hinges are solved via non-prismatic beam elements derived by the co-rotational approach. Finite element analysis (FEA) and experiment tests are performed to verify the modeling method. Finally, a multi-objective optimization is performed and the Pareto frontier is found via the NSGA-II algorithm.

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Study on a Flexure Hinge-Based Micro-Displacement Platform

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.179-180.1368 ◽

2011 ◽

Vol 179-180 ◽

pp. 1368-1373 ◽

Cited By ~ 1

Author(s):

Hua Wei Ji ◽

Yong Qing Wen

Keyword(s):

Theoretical Analysis ◽

Piezoelectric Actuator ◽

Vibration Suppression ◽

Fast Response ◽

Flexure Hinge ◽

Positioning System ◽

Experimental Demonstration ◽

Static Behavior ◽

Long Time ◽

Motion Range

In recent years, a flexure hinged micro-displacement platform driven by piezoelectric actuator is being widely used in vibration suppression and micro positioning applications for its fast response, nanometer resolution, no backlash, no friction and bigger driving force. This kind of precision micro positioning system with a high displacement resolution and wide motion range has been required for industrialized applications for a long time. This paper discusses the design and the characteristics of a flexure hinge-based micro-displacement platform driven by piezoelectric actuator, a four-bar parallel mechanism and a monolithic symmetrical mechanism are adopted in the design. An analytical model is presented and a series of formulae for the static behavior of the platform are derived. Based on the theoretical analysis, the optimum design schema is put forward. The experimental demonstration to study the performance of the platform is described, and the method for reducing nonlinearity errors is proposed. The experimental results are in close agreement with those predicted by the theoretical analysis.

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Design and Characterization of a Flexible Micro-Displacement Manipulator

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.221.449 ◽

2011 ◽

Vol 221 ◽

pp. 449-454

Author(s):

Hua Wei Ji ◽

Xiao Ping Hu

Keyword(s):

Theoretical Analysis ◽

Vibration Suppression ◽

Fast Response ◽

Flexure Hinge ◽

Experimental Demonstration ◽

The Finite Element Method ◽

Mechanical Joints ◽

Flexure Hinges ◽

Two Degree Of Freedom

For its fast response, nanometer resolution, no backlash, no friction and bigger driving force, flexure hinge has been commonly used as a substitute for mechanical joints in the design of micro-displacement mechanisms used in vibration suppression and micro-positioning applications. However, inaccurate modeling of flexure hinges deteriorates the positioning accuracy. In this paper, a planar two-degree-of-freedom (DOF) parallel four-bar manipulator is designed with the intention of accurate flexure hinge modeling. A 1-DOF flexure hinge is considered, a static analysis and a dynamic analytical model of parallel four-bar manipulator is presented. Simulation result based on the finite element method is coincident to the analytic result. Based on the theoretical analysis, the experimental demonstration to study the performance of the manipulator is described, and experimental results are in close agreement with those predicted by the theoretical analysis.

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Nonlinear modeling and analysis of compliant mechanisms with circular flexure hinges based on quadrature beam elements

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

10.1177/0954406218802945 ◽

2018 ◽

Vol 233 (9) ◽

pp. 3277-3285 ◽

Cited By ~ 1

Author(s):

SiQiang Xu ◽

XiaoBo Zhu ◽

ZeGuang Dong ◽

PinKuan Liu

Keyword(s):

Compliant Mechanisms ◽

Compliant Mechanism ◽

Beam Element ◽

System Level ◽

Weighting Coefficient ◽

Flexure Hinge ◽

Tangent Stiffness Matrix ◽

Flexure Hinges ◽

Geometrically Exact Beam ◽

Bridge Type

Linear modeling approaches for compliant mechanisms attract significant attention. However, geometrical nonlinearities require consideration generally because they may result in the modeling error. This paper presents a nonlinear quadrature beam element modeling approach for compliant mechanisms. The geometrically exact beam theory is employed as the basis for the element. Meanwhile, the element tangent stiffness matrix is obtained by using the weak form quadrature element method, which does not need shape functions any more and only performs simple algebraic operations of weighting coefficient matrices. One quadrature beam element is needed to model a flexure hinge. For validating the effectiveness of the proposed approach, typical circular flexure hinges are employed. Moreover, a typical bridge-type compliant mechanism is studied by the proposed approach. Finally, the efficiency and accuracy of the proposed approach are verified by comparing with the finite element results. Meanwhile, the results show that the shear effect can be ignored, when a single flexure hinge is investigated. Nevertheless, the nonlinear behavior of compliant mechanisms is affected at the system level. In addition, the magnification ratio of a bridge-type compliant mechanism is related to the width and material of the structure when nonlinearity is considered.

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Force tracking control of grinding end effector based on backstepping + PID

Industrial Robot the international journal of robotics research and application ◽

10.1108/ir-10-2020-0229 ◽

2021 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Shijie Dai ◽

Shining Li ◽

Wenbin Ji ◽

Zhenlin Sun ◽

Yufeng Zhao

Keyword(s):

Mathematical Model ◽

Linear System ◽

Control Strategy ◽

Grinding Force ◽

Constant Force ◽

End Effector ◽

Content Type ◽

Modeling And Analysis ◽

The Mathematical Model ◽

Automobile Wheel

Purpose This study aims to realize the constant force grinding of automobile wheel hub. Design/methodology/approach A force control strategy of backstepping + proportion integration differentiation (PID) is proposed. The grinding end effector is installed on the flange of the robot. The robot controls the position and posture of the grinding end actuator and the grinding end actuator controls the grinding force output. First, the modeling and analysis of the grinding end effector are carried out, and then the backstepping + PID method is adopted to control the grinding end effector to track the expected grinding force. Finally, the feasibility of the proposed method is verified by simulation and experiment. Findings The simulation and experimental results show that the backstepping + PID strategy can track the expected force quickly, and improve the dynamic response performance of the system and the quality of grinding and polishing of automobile wheel hub. Research limitations/implications The mathematical model is based on the pneumatic system and ideal gas, and ignores the influence of friction in the working process of the cylinder, so the mathematical model proposed in this study has certain limitations. A new control strategy is proposed, which is not only used to control the grinding force of automobile wheels, but also promotes the development of industrial control. Social implications The automatic constant force grinding of automobile wheel hub is realized, and the manpower is liberated. Originality/value First, the modeling and analysis of the grinding end effector are carried out, and then the backstepping + PID method is adopted to control the grinding end effector to track the expected grinding force. The nonlinear model of the system is controlled by backstepping method, and in the process, the linear system composed of errors is obtained, and then the linear system is controlled by PID to realize the combination of backstepping and PID control.

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Design, modeling, and analysis of wedge-based actuator with application to clutch-to-clutch shift

Proceedings of the Institution of Mechanical Engineers Part D Journal of Automobile Engineering ◽

10.1177/0954407017727178 ◽

2017 ◽

Vol 232 (9) ◽

pp. 1149-1166

Author(s):

Fengyu Liu ◽

Li Chen ◽

Jian Yao ◽

Chunhao Lee ◽

Chi-kuan Kao ◽

...

Keyword(s):

Dynamic Models ◽

Fast Response ◽

Physical Structure ◽

Modeling And Analysis ◽

Shift Quality ◽

Actuation System ◽

Automatic Transmissions ◽

Potential Alternative ◽

Low Efficiency ◽

Actuation Systems

Clutch-to-clutch shift technology is a key enabler for fast and smooth gear shift process for multi gear transmissions. However, conventional hydraulic actuation systems for clutches have drawbacks of low efficiency, oil leakage and inadequate robustness. Electromechanical devices offer potential alternative actuators. In this paper, a novel motor driven wedge-based clutch actuator, featuring self-reinforcement, is proposed. The design concept and physical structure are thoroughly described. Dynamic models for the actuation system and vehicle powertrain are validated by experiments. Upshift and downshift processes at different engine throttle openings, clutch clearances and friction coefficients are discussed. The results show that, the self-reinforcement ratio is tested as 9.6; at the same time, the shift quality is comparable to that of the conventional hydraulic actuated clutch in automatic transmissions in terms of the shift duration (about 1 s) and vehicle jerk (<10 m/s3). Taking advantage of fast response of the actuation DC motor, the wedge-based actuator is robust dealing with uncertain clutch clearance and friction coefficient. Therefore, the wedge-based clutch actuator has potential to provide acceptable performance for clutch-to-clutch shift.

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Finite Element Analysis of the Chassis for Sugarcane Leaf Cutting Off Returning to Field Machinery

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.915-916.305 ◽

2014 ◽

Vol 915-916 ◽

pp. 305-308

Author(s):

Jing Wang ◽

Yu Xing Wang ◽

Yan Qin Tang ◽

Dian Wu Zhang ◽

Zhen Hua Xu ◽

...

Keyword(s):

Finite Element ◽

Working Conditions ◽

Maximum Stress ◽

Excitation Frequency ◽

Allowable Stress ◽

Ansys Software ◽

Element Analysis ◽

Stress Contour ◽

Leaf Cutting ◽

Design Requirements

By modeling of sugarcane leaf cutting off returning to field machinery chassis and loading, this paper simplifies reasonably several different conditions of the chassis to the two forms. The finite element is used for the solution of the problem by using ANSYS software, solving the node stress contour of the chassis. Compared the maximum stress in the most dangerous working conditions to the allowable stress of the material, the result verifies the chassis strength to meet the design requirements. According to the vibration of the chassis at work, analyzing the first sixth modal of the chassis, and comparing with excitation frequency shows that the design of the chassis avoids the excitation frequency, which does not cause resonance at work. The results show that the chassis meets the design requirements.

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