2012.03.21, CLIC Test Module Meeting

Concept of ‘hexapod type’ DB Quad

adjustable support

Mateusz Sosin

Mateusz Sosin Concept of ‘hexapod type’ DB Quad adjustable support

Alignment requirements

Mateusz Sosin Concept of ‘hexapod type’ DB Quad adjustable support

Alignment requirements

Ergonomy of alignment (according to low access space)!!! Easy acces to all regulation components Easy acces to all blocking components (if not self-blocked) Predictable kinematics of support during regulation

Mechanical requirements All regulation components have to be fitted into accesible space Amount of „friction” components reduced to minimum Locknig after adjustment shall not modify the adjustment performed (self-locking

solution preffered) Alignment support need isotropic stiffness with value according to requirements (?)

What stiffness is required? Min. eigenfrequency of DBQ support? As small amount of components as possible Machining price as low as possible

Mateusz Sosin Concept of ‘hexapod type’ DB Quad adjustable support

Idea of modified ‚hexapod type’ mechanism

According to reduced space for alignment support Standard hexapod solution was changed to configuration with 3 support in vertical and 3

support in horizontal (that solution make kinematics much simple for manual regulation purposes)

Due to 5DOF regulations needed – one support has non adjustable length and is rigid longitudinally (according to Z – slide 2), rest of supports has adjustable lengths (l j)

Mateusz Sosin Concept of ‘hexapod type’ DB Quad adjustable support

Reverse kinematics of regulation for DBQ supporting platform

Platform - reverse kinematics: length (scalar): r - needed translation, R – rotation

matrix for support according to CS[0], lj-wectors of each support, sj – support coordinate in CS[1], dj – support coordinate in CS[0]

Iterational regulation in closed-loop-control: Supports A,B,C ~parallel to CS[0].y0,

supports D,E (red) ~parallel to CS[0].x0 We are looking reg.error only for

adequate vector components (here y):

We perform regulation with found values

At required regulation ranges - method shall be convergent up to 4 iterations

Mateusz Sosin Concept of ‘hexapod type’ DB Quad adjustable support

Adjustable support components Frame (girder interface) Supp. plate – DBQ interface Joints (stiff in supporting

direction, flexible transversally to supporting direction), threaded at end to perform regulation

Regulation screws Example of worm gear motion

transmission Using worm gear for driving

regulation screws make support self-locking. Also ergonomy of access to regulation components increase. Resolution of regulation step is multiplied by gear ratio.

Mechanical approach to realization of DBQ adjustable support

Schema shows only operating principle – don’t be sugested by used dimensions and schapes!!!

Longitudal blocade

Mateusz Sosin Concept of ‘hexapod type’ DB Quad adjustable support

Mechanical approach to realization of DBQ adjustable support – stiffness and shape of supports

Tasks to do: Perform simulations to find best shape

of flexible support with longitudinal stiffness as big as possible and transversal stiffness as low as possible capable to take requested deformation within spring deformation characteristics part of material

Joint characteristics: Support stiff longitudinally Prefered joint lenght: as short as possible Material has to work in spring part of

characteristics Possible material 34CrNiMo6 -> Rm up to 1200MPa

Mateusz Sosin Concept of ‘hexapod type’ DB Quad adjustable support

Mechanical approach to realization of DBQ adjustable support – regulation screws

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Manual regulations – differential thread mechanism

Using pair of different pitches and rotations threads gives us differential relativepith which can drastically increase resolution of regulations

Additional blocking clamp needed Eg.below – diff.pitch – 0,5mm->res=~1,5µm

Worm gear + transmission shaft Using worm gears & transmission shafts for driving

positioning screws we can increase resolution (nuts have to be fastened in bearings, ball screw prefered)

Worm gear mechanism can be self locking Ergonomy of using adjustable support increase –

all regulation components accesible at one side of DBQ

Easy to integrate motorization of support

Mateusz Sosin Concept of ‘hexapod type’ DB Quad adjustable support

Summary

After first analysis of ‚hexapod type’ DB Quad support design looks feasible to realize

Amount of regulation components and „friction” connections are reduced to minimum

In configuration with worm gear – structure is self locking and easy to integrate with external motorization components

Ergonomy of use and resolution meet the requirements

Mateusz Sosin Concept of ‘hexapod type’ DB Quad adjustable support

Thank you!