Vertical Stand

1 Description

CAD Geometry

The vertical stand represents a structural part of a machine tool. On one of its surfaces there are guide rails located. On these rails a tool slide is moving due to the machining process the slide has to perform by the machine tool on top. The machining process produces a certain amount of heat which is transported through the structure into the vertical stand. This heat source is considered to be a temperature input at the guide rails. This transfered heat amount leads to deformations within the device induced by the prevailed temperature field denoted by $x$. The evolution of this field is modeled by the heat equation

$c_p\rho\frac{\partial{x}}{\partial{t}}=\nabla.(\lambda\nabla x)=0$

with the boundary conditions

$\lambda\frac{\partial x}{\partial n}=q \qquad\qquad\qquad$ on $\Gamma_{slide}$ (surface where the tool slide is moving on the guide rails),

describing the heat transfer between the tool slide and the vertical stand and

$\lambda\frac{\partial x}{\partial n}=\kappa(x-x_{ext})$ on $\Gamma_{surf}$ (remaining boundaries),

which describes the heat transfer to the ambience.

The heat load $q$ induced by the slide and the external temperature $x_{ext}$ serve as the input $u$ of the corresponding state-space system.

The position of the moving slide has been included into the system as a parameter dependency $\mu$. Due to this motion the boundary $\Gamma_{Slide}$, where the input acts on the system is varying. Thus, the system matrix $A$ and the input matrix $B$ become parameter dependent.

Finally, the system describing the heat evolution induced by the moving heat source is given by:

$\begin{array}{lll} E\dot{x}&=A(\mu)x+B_{surf}x_{ext}+B_{slide}(\mu)q,\\ &=A(\mu)x+B(\mu)u,\\ \end{array}$

where

$\begin{array}{lll} B(\mu)&=[B_{surf}, B_{slide}(\mu)],\\ u&=[x_{ext}^T,q]^T.\\ \end{array}$

The quantity $x_{ext}$ can be assumed as a vector including different ambient temperatures corresponding to different locations of the geometry.

2 Acknowledgement & Origin

This model was developed and investigated

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