Simulation, Design, and Testing of a High Performance Multi-Axis Hexapod for Vibration Isolation

2007 ◽  
Author(s):  
Bernie R. Jahn
Keyword(s):  
High Performance ◽  
Vibration Isolation ◽  
Low Frequency ◽  
Modal Testing ◽  
Simulation Design ◽  
Frequency Spread ◽  
Optimum Geometry ◽  
Six Degree Of Freedom ◽  
Design And Testing ◽  
Base Structure

This paper describes the simulation, design, and testing of a high-performance six degree-of-freedom hexapod for the purpose of isolating sensitive payloads from low-frequency vibrations. Design criteria required the hexapod to support a generic payload up to 500 lb with an isolation plunge frequency of approximately 1 Hz. Simulations were performed using Matlab in order to determine the optimum geometry of the base and platform structures in order to provide the best combination of translation-rotation uncoupling, frequency spread, plunge frequency, and jitter. Based on these simulation results, hexapod base and platform structures were designed and fabricated based on a 50 inch-diameter platform size. All of the accumulators and pneumatic hardware were embedded into the base structure to allow for a totally contained system. Modal testing of the hexapod was performed in order to verify the modes predicted by the model.

scholarly journals Design and Characteristics of a Novel QZS Vibration Isolation System with Origami-inspired Corrector

2021 ◽  
Author(s):  
Shiwei Liu ◽  
Gaoliang Peng ◽  
Kang Jin
Keyword(s):  
High Performance ◽  
Vibration Isolation ◽  
Vibration Suppression ◽  
Virtual Work ◽  
Structural Parameters ◽  
Low Frequency ◽  
Harmonic Balance Method ◽  
Equivalent Transformation ◽  
Isolation System ◽  
Vibration Isolation System

Abstract A new class of quasi-zero-stiffness (QZS) vibration isolation systems, inspired by the origami metamaterial, is proposed to achieve high-performance vibration suppression in this paper. According to the mechanical characteristics of Tachi-Miura origami (TMO) with single degree-of-freedom, the nonlinear geometric relationship is developed with the folding angle as the master variable. By utilizing equivalent transformation and virtual work principle, the static model is established, the influence of structural parameters on stiffness is investigated, and the negative stiffness mechanism of origami mechanism is revealed. By adding a linear spring with positive stiffness to the origami in parallel, the Tachi-Miura origami vibration isolator (TMOriVi) is obtained. Subsequently, the governing equation is presented by means of the harmonic balance method. Two types of instability situations, jump phenomenon and unbounded response, are studied, and their analytic criteria and relationship are derived. Finally, through the parametric influence analysis and a series of comparative studies, the effectiveness and superiority of the proposed isolator are verified. The proposed vibration isolation system with great design flexibility exhibits a significant potential in the field of low-frequency vibration isolation.

scholarly journals A six degree of freedom passive vibration isolator with quasi-zero-stiffness-based supporting

2018 ◽  
Vol 37 (2) ◽  
pp. 279-294 ◽  
Author(s):  
Jiying Tuo ◽  
Zhaoxiang Deng ◽  
Wei Huang ◽  
Heshan Zhang
Keyword(s):  
High Performance ◽  
Vibration Isolation ◽  
Structural Parameters ◽  
Dynamic Stiffness ◽  
Stability Boundary ◽  
Random Excitation ◽  
Degree Of Freedom ◽  
Vibration Isolator ◽  
Vibration Attenuation Performance ◽  
Six Degree Of Freedom

A six degree of freedom nonlinear passive vibration isolator is proposed based on Stewart platform configuration with the quasi-zero-stiffness structure as its legs. Due to the high static stiffness and low dynamic stiffness of each leg, the proposed six degree of freedom system can realize very good vibration isolation performance in all six directions while keeping high static load-bearing capacity in a pure passive manner. The mechanic model of the proposed six degree of freedom isolator and the dynamic equation of the isolator are established successively. Theoretical analysis on cross coupling stiffness reveals that the system can demonstrate quasi-zero-stiffness property in all six degree of freedom. Moreover, an analysis on stability shows that the condition of structural parameters for the isolator to realize quasi-zero-stiffness is also the stability boundary of the system. A series of numerical simulations on displacement transmissibilities in coupled degree of freedoms, the coupling effects of transmissibility, and a dynamic response in random excitation are carried out to show the effectiveness of the proposed six degree of freedom isolator, as well as the influence of structural parameters on vibration attenuation performance. Considering its high performance in a simple passive manner, it can be foreseen that the proposed six degree of freedom isolator will be applied in various engineering practices with multi-degree of freedom vibration isolation.

scholarly journals High-Performance Ultra-Thin Spectrometer Optical Design Based on Coddington’s Equations

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 323
Author(s):  
Zhiwei Feng ◽  
Guo Xia ◽  
Rongsheng Lu ◽  
Xiaobo Cai ◽  
Hao Cui ◽  
...  
Keyword(s):  
High Resolution ◽  
Spectral Resolution ◽  
High Performance ◽  
Optical Design ◽  
Pixel Size ◽  
Simulation Design ◽  
Central Wavelength ◽  
Spot Radius ◽  
Unique Method ◽  
Almost All

A unique method to design a high-throughput and high-resolution ultrathin Czerny–Turner (UTCT) spectrometer is proposed. This paper reveals an infrequent design process of spectrometers based on Coddington’s equations, which will lead us to develop a high-performance spectrometer from scratch. The spectrometer is composed of cylindrical elements except a planar grating. In the simulation design, spot radius is sub-pixel size, which means that almost all of the energy is collected by the detector. The spectral resolution is 0.4 nm at central wavelength and 0.75 nm at edge wavelength when the width of slit is chosen to be 25 μm and the groove density is 900 lines/mm.

Engine Mount Optimization for Vibration Isolation in Motorcycles

2006 ◽  
Author(s):  
Sudhir Kaul ◽  
Anoop K. Dhingra ◽  
Timothy G. Hunter
Keyword(s):  
Optimization Problem ◽  
Vibration Isolation ◽  
Total Force ◽  
Engine Mounts ◽  
The Road ◽  
Design Variables ◽  
Swing Arm ◽  
Engine Mount ◽  
Six Degree Of Freedom

This paper presents a comprehensive model to capture the dynamics of a motorcycle system in order to evaluate the quality of vibration isolation. The two main structural components in the motorcycle assembly - the frame and the swing-arm - are modeled using reduced order finite element models; the power-train assembly is modeled as a six degree-of-freedom (DOF) rigid body connected to the frame through the engine mounts and to the swing-arm through a shaft assembly. The engine mounts are modeled as tri-axial spring-damper systems. Models of the front-end assembly as well as front and rear tires are also included in the overall model. The complete vehicle model is used to solve the engine mount optimization problem so as to minimize the total force transmitted to the frame while meeting packaging and other side constraints. The mount system parameters - stiffness, position and orientation vectors - are used as design variables for the optimization problem. The imposed loads include forces and moments due to engine imbalance as well as loads transmitted due to irregularities in the road surface through the tire patch.

Design of an effective vibration isolation system for measurements sensitive to low-frequency vibrations

2012 ◽  
Vol 30 (6) ◽  
pp. 063201 ◽  
Author(s):  
Katsuya Iwaya ◽  
Ryota Shimizu ◽  
Akira Teramura ◽  
Seiji Sasaki ◽  
Toru Itagaki ◽  
...  
Keyword(s):  
Vibration Isolation ◽  
Low Frequency ◽  
Isolation System ◽  
Vibration Isolation System

Research on Vibration Isolation Parameters of Double-Deck Isolation System of Heat Water Pump

2013 ◽  
Vol 694-697 ◽  
pp. 316-320
Author(s):  
Xiang Jun Kong ◽  
Er Ming Song ◽  
Chang Zheng Chen
Keyword(s):  
Power Flow ◽  
Vibration Isolation ◽  
Low Frequency ◽  
Mass Effect ◽  
Transmitted Power ◽  
Intermediate Mass ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Upper Deck ◽  
Vibration Power Flow

Isolation system of the heat water pumps can be simplified as a double sources exciting and double output double-deck vibration isolation system model, expressions of transmitted power flow and vibration speed to the basement are deduced based on the double sources exciting and double output double-deck vibration isolation system electric-force(E-F) analog picture, the curves of power flow and vibration speed transmitted to basement how the upper deck vibration isolation and intermediate mass effect are drawn by using mat lab program. The results show that the adjusting the upper deck vibration isolation stiffness parameters has little effect on the amplitude of vibration power flow, increasing intermediate mass can move first peak to the low frequency, increasing intermediate mass can obviously reduce t transmitted power flow and transmitted vibration speed amplitude to the basement.

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