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
Nice id
ea o
f N.C
hritin
!
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!