Vibration Characteristics of Disks-Spindle System in Hard Disk Drives

Luo

Fang

et al. 2011

AMR

Ultra-precision mechanism lies in the core of ultra-precision electromechanical equipment, and is characterized by direct electromagnetic driving, air bearing supporting and ultra-precise vibration-isolation, putting a great challenge on design methodology and tools. This paper presents a model template design method which can provide effective computer aided design and engineering tools for new system design by encapsulating the design methods and design experience of ultra-precision mechanism into series of design templates. The model template contains toolkits both for forward structural design applied to new systems, and for the analysis and optimization of existing systems, as well as mathematical model and visualization tool in physical domain. The model templates are encapsulated and assembled according to the dynamical parameters and specific design parameters. Using planar electromagnetic drive structure in ultra-precision positioning system as an example, this paper discusses the design scheme of structure’s model template in detail, and introduces fast calculation method for magnetic field and visualization program, as well as forward design method for electromagnetic coil structure. Fast scheme design and analysis for ultra-precision mechanism can be achieved by using design templates.

Section: 1system Dynamic Modeling and Optimization Processmentioning

confidence: 99%

Structural Feature-Based Model Templates Design for Ultra-Precision Positioning System

Luo

Fang

et al. 2011

AMR

“…The aerostatic bearing can be modeled as a set of distributed springs, and each one of them has only nonzero stiffness along the normal axis which represents the effect of finite area of pressurized air. Finite element method can be used to resolve problems in many applications such as structural dynamics [17,18] and fluid dynamics [8] , it is particular suitable for solving the pressure distribution of the aerostatic bearing with complex structures. The pressure distribution of the aerostatic bearing in the region S is denoted by p. Denote ds the finite area at position ( , )…”

Section: Modeling Of Aerostatic Bearing With Distributed Springsmentioning

confidence: 99%

Roll Vibration Analysis of Planar Aerostatic Bearings through a Distributed Spring Model

Jiang

Liu

et al. 2011

AMR

The aerostatic bearings used in guide ways in ultra precision motion stages can provide both normal stiffness and roll stiffness, which are critical to the dynamic characteristics and control of systems. The normal stiffness has been widely investigated so far, but the roll one has seldom been studied. A new method for analyzing the roll stiffness is proposed, in which the aerostatic bearing is modeled as a set of distributed springs. The stiffness distribution is obtained by using the derivate of the pressure distribution with respect to the air gap. All the distributed springs are then integrated by using the presented transformation and it leads to an equivalent spatial spring which contains both the normal stiffness and the roll stiffness. A planar aerostatic bearing is taken as an example to illustrate the procedure of the calculation. The proposed method can be used to predict the vibration characteristics of various kinds of aerostatic bearings under working conditions.

“…Calculation of the DOFs of complex mechanisms is fundamental to design, dynamic analysis and control of mechanisms such as robots, industrial manipulators, parallel machines, and precision motion stage [1][2][3][4] . The DOFs of a complex mechanism depends on not only the number and type but also the position and orientation of joints in the system [5] .…”

Section: Introductionmentioning

confidence: 99%

A New Algorithm for Calculating the Degrees of Freedom of Complex Mechanisms

Jiang

Luo

et al. 2011

AMR

A new algorithm is presented to calculate the degrees of freedom (DOFs) of spatial complex mechanisms by using the coefficient matrix of the linear constraint equations. A joint constraint matrix is firstly put forward for each kind of joint to formulate linear constraint equations in terms of spatial fine displacements of joint acting point with respect to joint frame. Two kinds of transformation are then proposed to rewrite all the constraint equations in terms of a set of fine displacements of all bodies and it leads to a set of homogeneous linear equations. The rank of the resulting coefficient matrix stands for the number of effective constraints and therefore the DOFs of the mechanism can be easily figured out. The proposed method can be widely used to solve the problem of DOFs for many spatial complex mechanisms, which may not be correctly solved with traditional approaches. Besides, the proposed method is very easy for implementation.