Papers by Keyword: Flexure Hinge

Abstract: The paper presents the model and design of a flexure-based precise 4 DOF degree of freedom positioning system for micro-positioning uses. The positioning system is featured with monolithic architecture, flexure-based joints and ultra-fine adjustment screws. The mathematical model for the output displacements of the positioning system has been verified by finite element analysis (FEA).

Abstract: In this paper, an ultra-precision positioning stage is introduced. The finite element method is used to establish the theoretical model, and the strain test system of experiment is established. The system includes the static strain test and the dynamic strain test. The test system contains the software and hardware system. The software system includes the static strain measurement software of DH3816, the programmable constant temperature and humidity chamber control software TEMI300, and the dynamic strain test system developed from NI Labview. The hardware system contains industrial personal computer (IPC), piezoelectric (PZT) actuator, static strain gauge of DH3816, strain amplifier of YE1817, NI USB-6009 multifunction data acquisition card, strain gauge, programmable temperature and humidity chamber, and precision positioning stage. The experimental test is carried out to examine the theoretical analysis considering thermal effect. Experimental results and analytical results indicate that whether the stresses increase or decrease linearly or nonlinearly depend on the function of the temperature to the time during the transient response same as the stresses increase or decrease linearly during the steady response under uniform temperature change. The dynamic responses of platform are affected by the temperature change, and it is essential to consider thermal effect when analyzing compliant mechanisms.

Abstract: In this paper, a flexure hinge micro-displacement magnifying mechanism was designed, which was based on the principles of triangle amplification, and the amplifier was driven by piezoelectric stack. The displacement of piezoelectric stack was amplified by the flexure hinges micro-displacement magnifying mechanism. In order to test the static and dynamic carried on it. Not only the characteristics of good linearity, magnification, high positioning resolution and high frequency response achieved but also the design theory approved its correctness in the experiment.

Abstract: Unlike rigid-body mechanisms, compliant mechanisms (CMs) gain some or all of their motion from relative flexibility of their joints. This paper presents a pseudo-rigid-body model (PRBM) method and virtual work to design and analyze kinematics and dynamics for compliant rotary joints or flexure hinges in the processing of compliant mechanisms. The stress at flexible pivot, the nonlinear-large deflection of flexure hinge, the relationship between displacement and force and/or torque, stress were taken into account in this work based on PRBM. A numerical software package, ANSYS, was exploited to illustrate schematic diagram of the stress versus to horizontal displacement of free end AB of flexure hinge. A mechanism with the desired structure is that one of the most popular aspects, which is needed to take into account in the design phase in advance. The results revealed that the proposed effective approach can be further easily applied in compliant mechanism structures. Future work will focus on multi-objective structural optimization of the flexure hinge.

Abstract: This paper presents the design of a new compact three-axis in-plane motion stage which work directions are X, Y, θz. The proposed stage consists of four amplification flexure structures and four piezoelectric actuators. The amplification structure uses bridge type amplification mechanism and notch type flexure guide hinge. The size of the stage is 150×150×30mm³ and has 50×50mm² hollow in the center of the stage.

Abstract: In this paper we present a parallel robot with flexure hinges for target alignment system of a high power laser facility. The robot contains a parallel mechanism with 6 DOF which has nanometer positioning accuracy and is driven by six linear actuators. We design a new flexure hinge which has higher accuracy, strong environmental suitability and simple structure compared with conventional flexure hinge which has backlash and friction issues. The kinematics analysis of the parallel mechanism is also discussed. The simulation analysis of the mechanism is done by ADAMS. The mechanism is proved meeting the design requirements by comparing the results of the theory analysis and the simulations.

Abstract: In order to design a large aperture primary mirror with the diameter of 1150 mm, the parameters impacting on gravity deformation of the mirror were analyzed and discussed in detail, including material selection, diameter-thickness ratio, the number of the support points, location selection and lightweight structure, etc. A novel space mirror structure system was put forward, and its back was opened and supported by six points on back. The dynamic and static and thermal characteristics were analyzed based on the finite element method. Analysis results showed the surface figure accuracy reached to RMS 14.5nm under the action of gravity load along the optical axis direction and the first-order natural frequency was 214Hz which met to the designed indexes requirements.

Abstract: Structural design of large aperture mirror is one of the key technologies for space telescope development. To meet the requirements of high stiffness, strength and thermal dimensional stability, some factors such as support scheme, materials selection, lightweight design and flexible support design were taken into account. The three supports location of the mirror was determined according to the modal analytical solution. By adjusting the parameters of flexure hinge, influences of gravity, assembly stress and thermal stress on the mirror were reduced obviously. Finite element analysis (FEA) results indicate that the surface accuracy reach to rms10.2nm and 10.8nm under the gravity along optical axis direction and 5°C uniform temperature rise respectively, the fundamental frequency of the mirror component is 268Hz. Dynamics test shows that the first order natural frequency is 256Hz, which shows an error less than 5% compared to FEA results.

Abstract: Flexure hinge has been widely used in high precision micro-positioning mechanism and the most common type is right circular flexure hinge. Firstly, asymmetrical right circular flexure hinge is presented and the structure factor is introduced in the paper according to the size of the cutting arc radius of both sides of right circular flexure hinge. Then, asymmetrical right circular flexure hinge is classified by the value of structure factor. Finally, the analytical expression of rotation stiffness for asymmetrical right circular flexure hinge is deduced, and the relationships between the structure factor and rotation stiffness are calculated with Matlab software. The analytic result has an important significance to design flexure hinge.

Abstract: The construction and the operating principle of the novel micro-angular vibration testbed (MAVT) are presented, the MAVT is designed to complete the angular performance testing for the micro sensor and parts such as MEMS-gyro, angular accelerometer. A systemic design procedure of the optimized flexure hinge and general voice coil actuator (VCA) to fine single-axis MAVT actuator are introduced for fast and precision actuation. A method for measuring frequency response function by means of a displacement sensor electric eddy current sensor is designed. To verify the performance of the designed MAVT, frequency response of the system are performed, the differential equation of the pull-tilting motion is established according to the Lagranges equation, the formula of the natural frequency is derived, and the model analysis of the MAVT is also carried out with the help of limited element analysis. The static stiffness experiments show that the angular stroke of the MAVT is 1° and preliminary tests performed on the closed-loop control system indicate that angular resolution of 1 can be achieved. Model experiments performed on the prototype of MAVT are presented and the theoretic result fits with the result of experiment (250Hz). For fast and precision actuation performances, design parameters are selected based on the dynamic model of VCA and flexure hinge, and design process is completed. The model results can be provided for the construction design of the MAVT. Conventional platforms of angular performance testing are bulky and costly. Analysis and experiments results indicate that the novel MAVT is an efficient platform to complete the angular performance testing for micro sensor and parts.